Note: Descriptions are shown in the official language in which they were submitted.
WO 2022/008018 PCT/D1(2021/050227
1
Multi-stage Compressor
The present invention concerns a multi-stage compressor for com-
pressing a fluid, the compressor comprising:
5 two or
more cylinders each having a compression chamber and a pis-
ton, so that a fluid in each of the compression chambers can be compressed
by the associated piston;
the cylinders being connected in series such that a fluid entering an
inlet of the compressor can be compressed to a first pressure in the compres-
10 sion
chamber of a first cylinder and, then, enter into the compression chamber
of a second cylinder where the compressed fluid is compressed to a second
higher pressure before the fluid exits from an outlet of the compressor.
Multi-stage compressors are known for example from US2151825 with
multiple cylinders in line driven by a standard crankshaft shaft.
15
Compressors for generating pressure are known for example from
W007036972A1 which discloses a hydraulic machine with radial cylinders hav-
ing an improved bearing in the crankshaft, i.e. a machine with radial
cylinders
fixed to its crankcase, advantageously for pressurised hydraulic liquids, in
which the respective connecting rod is coupled with the crankshaft through an
20
improved bearing with rolling friction, so as to reduce the parts worked, to
sim-
plify the processing and assembly processes, increasing the mechanical per-
formance of the machine and improving its lifetime.
A first aspect of the present invention concerns a multi-stage compres-
sor according to the introduction, wherein each piston is driven by one and
the
25 same crankpin of the compressor.
In this way, as the pistons are driven by one and the same crankpin,
and therefore each piston does not require its own crankpin, the multi-stage
compressor may be made more compact in the axial direction of the compres-
sor i.e. in the direction the crankpin extends.
30 A
multi-stage compressor may be understood as a compressor in
which a fluid is compressed to a first pressure in a compression chamber of a
first cylinder and this compressed fluid is then at least passed into a
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
2
compression chamber of a second cylinder where the compressed fluid is com-
pressed even further to a second, higher pressure. The compression chamber
of each cylinder may define a stage of compression of the multi-stage com-
pressor. The multi-stage compressor may comprise more than two stages
5 and/or
cylinders with compression chambers. The fluid entering the inlet of the
compressor may be pre-compressed i.e. the fluid entering the inlet may already
be compressed. That is, the fluid entering the inlet of the compressor may be
at a pressure above atmospheric pressure. For example, the fluid entering the
inlet may be at a pressure of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16,
10 17,
18, 19, 20, 21, 22, 23, 24, 25 bar or more above atmospheric pressure. This
can facilitate the generation of fluid compressed to even higher pressures by
the compressor.
The fluid may be any suitable fluid, liquid, and/or gas. The fluid may
be a compressible fluid.
15 The
crankpin may extend in an axial direction and/or a radial direction
of the compressor. The crankpin may rotate about a rotation axis to drive the
pistons. The crankpin may be positioned with a distance to the rotation axis.
The crankpin may be positioned with a distance to the rotation axis in the
radial
direction. There may be a distance from a center axis of the crankpin to the
20 rotation axis. The rotation axis may be located outside of a periphery of
the
crankpin. The rotation axis and the axial direction may be parallel. The
crankpin
may be attached to a rotatable crankshaft. The crankshaft may extend exter-
nally of the compressor housing. The crankshaft may extend in the axial direc-
tion of the compressor. The crankshaft may extend beyond the housing of the
25
compressor. The crankshaft of the compressor may be configured such that a
drive unit and/or a crankshaft of another compressor may be coupled to it. The
rotation axis may be concentric with the crankshaft. A radial direction may ex-
tend perpendicularly from the axis of rotation. The crankpin may be
cylindrical
with a length extending in the axial direction and a crankpin diameter
extending
30 perpendicularly to the axial direction. The crankpin may be positioned with
a
distance "D" from the rotation axis to the center axis and/or periphery of the
crankpin of at least 0.1, 0.25, 0,5, 1, 2, 3, 4, 5, or more crankpin radii.
The
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
3
periphery of the crankpin may overlap the rotation axis when looking in a
direc-
tion parallel to the rotation axis. The crankpin may have an outer diameter
that
is equal to or larger than a largest outer diameter of at least one and/or
two,
and/or three, and/or four, and/or five, and/or six or more pistons of the com-
pressor. The crankpin may have an outer diameter that is equal to or larger
than a largest diameter of all pistons of the compressor. The crankpin may
have
a diameter that is equal to or more than 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7,
1.8, 1.9,
2 times the largest outer diameter of the pistons of the compressor. This may
allow shorter pistons to be used and/or may reduce the lever arm acting on the
crankpin and potentially thereby on the axis of rotation and/or crankshaft. Re-
ducing the lever arm may reduce the amount of torque required to drive the
compressor, whereby the power consumption of the compressor may be re-
duced and the efficiency increased. At least one, two, three, four, five, six
or
more pistons may have a substantially constant outer diameter and/or a con-
stant outer diameter. A substantially constant outer diameter and/or constant
outer diameter may be understood as the outer diameter being substantially
the same and/or the same along the entire length of the piston(s).
At least one, two, three, four, five, six or more pistons may have differ-
ent piston lengths "L". The sliding shoes may be substantially identical or
iden-
tical to each other. The holding rings may be substantially identical or
identical
to each other. Identical sliding shoes and/or identical holding rings may
facili-
tate the stroke length being defined by the piston length of the associated
pis-
ton, particularly as the pistons are driven by the same crankpin and/or
crankpin
bearings. The length "L" of a piston may be a length extending in the radial
direction. The length of a piston may extend from a top surface of a top end
to
a bottom surface of a bottom end of the piston. The diameter of a piston may
extend orthogonally to its length. The length of a piston may alternatively be
denoted piston length. A stroke length of a piston may be defined as the dis-
tance a piston travels in the associated cylinder and/or compression chamber
in operation of the compressor. Additionally or alternatively, a stroke length
may
be a distance a top end and/or a bottom end of a piston travels between the
bottom most point of a stroke and the upper most point of a stroke.
Additionally
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
4
or alternatively, a stroke length may be a distance a top end and/or a bottom
end of a piston travels between bottom dead center and top dead center.
The term "associated" may be understood as being linked to or directly
working together with, potentially in contact with. For example a cylinder may
have an associated piston and an associated compression chamber, the asso-
ciated piston working inside the associated compression chamber. Similarly, a
cylinder and/or piston may have an associated seal such as a rod seal for seal-
ing between said piston and said cylinder.
The cylinders may be located about the axis of rotation. The cylinders
may extend in the radial direction away from the axis of rotation. The compres-
sion chambers may be located within the associated cylinders. The compres-
sion chambers may be a hollow spacing within a cylinder in which the fluid is
compressed. The hollow spacing may take up a fraction of a total volume of a
cylinder. The hollow spacing may be cylindrical. The compressor may comprise
at least 3, 4, 5, or 6 or more cylinders. The compressor may comprise 2, 3, 4,
5, or 6 cylinders. If more than two cylinders are present, the fluid may
succes-
sively enter into and be compressed to a successively higher pressure in the
compression chamber(s) of the additional cylinder(s).
The pistons may be cylindrical and/or disc-shaped. The pistons may,
in operation, move up and down and/or substantially, substantially only, or
only
in the radial direction of the compressor and/or in an axial direction of the
re-
spective piston or only or substantially only in an axial direction of the
respec-
tive piston in the combustion chambers and/or cylinders. The pistons may, in
operation, oscillate up and down in the combustion chambers and/or cylinders.
The pistons may have a diameter or outer diameter, or largest outer diameter
"d", that is smaller than or equal to a diameter or inner diameter of the
associ-
ated combustion chambers. There may, potentially in operation and/or at stand-
still of the compressor, be a gap between an inner wall of a compression cham-
ber and a periphery of the associated piston. The piston may, potentially in
operation and/or at standstill of the compressor, be distanced by a gap from
an
inner wall of the compression chamber. The gap may surround an entire pe-
riphery of the associated piston. The pistons may extend in the radial
direction.
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
The pistons may comprise and/or consist of a solid material. The pistons may
comprise and/or consist of a hollow material. A hollow material may be lighter
than a solid material whereby efficiency of the compressor may be improved
as the inertia of the piston may be reduced and less mass has to be moved to
5 compress a fluid. The pistons may be made of metals, metal alloys, e.g.
brass,
steel, aluminium or aluminium alloys, bronze, and/or combinations thereof. The
pistons may be made of steel with an aluminium core.
An inlet of the compressor may be understood as an entry duct for fluid
to enter the compressor. The inlet may enter into the compression chamber of
10 a first cylinder of the compressor i.e. into the first stage of the
compressor. The
inlet may be understood as a point of entry for fluid into the compressor.
Fluid
may enter the compression chamber of a first cylinder of the compressor i.e.
the first stage of compression of the compressor through the inlet. The inlet
may comprise a non-return valve as described herein for preventing fluid from
15 flowing from a compression chamber and outside of the chamber through
the
inlet. The inlet and outlet of the compressor may be positioned on the same
side of the compressor. This may provide easy access to the inlet and outlet.
An outlet of the compressor may be understood as an exit duct for fluid
to exit the compressor. The outlet may exit out of the compression chamber of
20 a final cylinder of the compressor i.e. the final stage of compressor.
The outlet
may be understood as a point of exit for fluid out of the compressor. Fluid
may
exit the compression chamber of a final cylinder of the compressor i.e. the
final
stage of compression of the compressor through the outlet. The outlet may
comprise a non-return valve as described herein for preventing fluid from flow-
25 ing from outside of the compression chamber and into the chamber through
the
outlet.
The crankpin may be located with a distance to the crankshaft i.e. such
that there is a distance between a periphery of the crankpin and a periphery
of
the crankshaft. The crankpin may be located at a point located radially from
the
30 axis of rotation of the crankshaft. The crankpin may extend in parallel
with the
crankshaft. One or more bearings such as e.g. a roller bearing and/or plain
bearing may be attached and/or mounted on the crankpin. Two roller bearings
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
6
may be mounted on the crankpin. The crankpin may be a part separate of the
crankshaft. The crankpin may comprise, consist of, and/or be coated with a
plain bearing material such as e.g. metals, metal alloys, or polymers e.g.
brass,
steel, aluminium or aluminium alloys, bronze, PTFE, and/or combinations
thereof.
The crankpin and/or one or more bearing(s) positioned on the crankpin
may be positioned with a distance from the rotation axis of the crankshaft to
a
center axis and/or a periphery of the crankpin, this distance potentially
being at
least 0.1, 0.25, 0,5, 1, 2, 3, 4, 5, or more of a radius of the crankpin. A
periphery
of the crankpin and/or bearing(s) positioned on the crankpin may overlap the
rotation axis. This may reduce the length of a lever arm acting on the
crankpin
and/or the rotation axis of the crankshaft. Additionally or alternatively, the
crankpin and/or bearing(s) may have an outer diameter that is equal to or
larger
than a largest outer diameter of at least one and/or two and/or three and/or
four
and/or five and/or six or more pistons of the compressor. Additionally or
alter-
natively, the crankpin and/or bearing(s) may have an outer diameter that is
equal to or larger than a largest diameter of all pistons of the compressor.
Ad-
ditionally or alternatively, the crankpin and/or bearing(s) may have an outer
di-
ameter that is equal to or more than 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8,
1.9, 2
times the largest outer diameter of the pistons of the compressor. This may
allow shorter pistons to be used and/or may reduce the length of the lever arm
acting on the crankpin and potentially thereby on the axis of rotation and/or
crankshaft. Reducing the length of the lever arm may reduce the torque re-
quired to drive the compressor, whereby the power consumption of the corn-
pressor may be reduced and/or the efficiency thereof increased. The one or
more bearings positioned on the crankpin may alternatively be denoted crank-
pin bearing(s). The crankpin bearing(s) may drive the pistons of the compres-
sor. The crankpin bearings may be axial-radial bearings such as axial-radial
roller bearings.
A lever arm may also be denoted a moment arm. The length of the
lever arm acting on the crankpin and/or the rotation axis may be equal to or
less than 200%, 190%, 180%, 170%, 160%, 150%, 140%, 130%, 120%, 110%,
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
7
100%, 90%, 80%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%,
20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%,
6%, or 5% of smallest and/or largest stroke length of the pistons of the com-
pressor. Additionally or alternatively, the length of the lever arm acting on
the
5 crankpin and/or the rotation axis may be equal to or less than 90%, 80%,
70%,
60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 19%, 18%, 17%, 16%,
15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, or 5% of a piston length
of the shortest and/or longest piston of the compressor. The crankpin and/or
crankpin bearing(s) may have an outer diameter that is equal to or more than
10 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5,
2.6, 2.7, 2.8,
2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4,
4.5, 4.6, 4.7,
4.8, 4.9, or 5 times a smallest and/or largest stroke length of each piston of
the
compressor. The crankpin and/or crankpin bearing(s) may have an outer diam-
eter that is equal to or more than 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8,
0.9, 1, 1.1,
15 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 times a piston length of the
shortest and/or
longest piston of the compressor. The technical features in this paragraph may
provide a shorter lever arm with the advantages as described above.
The crankshaft may be supported in the compressor housing by one
or more crankshaft bearings e.g. plain and/or roller bearings such as
described
20 herein. The crankshaft may comprise at least two interconnected shafts.
Each
shaft may be supported in the compressor housing by one or more crankshaft
bearings e.g. plain and/or roller bearings such as described herein. The at
least
two shafts may be concentric with each other and/or the rotation axis. The at
least two shafts may be of equal length and/or diameter. The at least two
shafts
25 may be of different lengths. At least one of the at least two shafts may
be con-
figured for engaging with a drive unit for driving the compressor. At least
one
of the at least two shafts may be a driveshaft for driving the compressor. The
crankpin may be located between two of the at least two shafts. The crankpin
may be mounted eccentrically to the at least two shafts. The crankpin may in-
30 terconnect two of the at least two shafts. The crankpin may interconnect
two
shafts by being clamped to the two shafts. The crankpin may interconnect two
of the at least two interconnected shafts by being clamped and secured to a
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
8
respective end of each of the two shafts by a bolt clamp mechanism. The crank-
pin may be clamped and secured to a respective end of each of the two shafts
at respective ends of the crankpin. The crankpin and the at least two shafts
may be in one piece. The crankpin and the at least two shafts may be machined
5 from one piece to form a continuous unit.
The compressor may be electrically driven by for example an electric
drive unit powered by e.g. battery, solar, wind, wave, nuclear, thermal energy
sources, preferably sustainable energy sources. Additionally and/or alterna-
tively, the compressor may be driven by a fossil fuel powered drive unit.
10 A piston may extend beyond its associated compression chamber
and/or cylinder towards the axis of rotation. A total length of a piston in a
radial
direction may be longer than a total length of the associated compression
chamber in the radial direction. A piston at top dead center (TDC) i.e. at the
top
point of its stroke may extend beyond its associated cylinder towards the axis
15 of rotation. A piston may extend away from and beyond its associated com-
pression chamber and/or cylinder in a direction facing towards the crankpin. A
piston at top dead center may extend away from and beyond its associated
compression chamber and/or cylinder in a direction facing towards the crank-
pin. Each cylinder and/or piston may comprise a linear seal such as a piston
20 seal and/or rod seal for sealing between the associated piston and
cylinder.
The, or one or more, cylinder(s) may comprise one or more rod seals for
sealing
against the piston. The piston may be the associated piston of the cylinder.
For
example, the first cylinder and/or a cylinder base of the first cylinder may
com-
prise one or more rod seals for sealing against the associated piston of the
first
25 cylinder, and/or the second cylinder and/or a cylinder base of the
second cylin-
der may comprise one or more rod seals for sealing against the associated
piston of the second cylinder, and/or a third cylinder and/or a cylinder base
of
the third cylinder may comprise one or more rod seals for sealing against the
associated piston of the third cylinder, and/or a fourth cylinder and/or a
cylinder
30 base of the fourth cylinder may comprise one or more rod seals for sealing
against the associated piston of the fourth cylinder, and/or a fifth cylinder
and/or
a cylinder base of the fifth cylinder may comprise one or more rod seals for
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
9
sealing against the associated piston of the fifth cylinder, and/or a sixth
cylinder
and/or a cylinder base of the sixth cylinder may comprise one or more rod
seals
for sealing against the associated piston of the sixth cylinder, and so forth.
The
piston may comprise one or more linear seals such as a piston ring and/or
shaft
5 seal. The seals may be hydraulic and/or pneumatic seals. The cylinder
and/or
piston may comprise a combination of hydraulic and/or pneumatic seals. A lin-
ear seal may be positioned circumferentially in a cylinder or on a piston. A
linear
seal may be positioned in the circumference of a cylinder and/or compression
chamber and/or on the circumference of a piston. The linear seal may be posi-
10 tioned in the cylinder and/or compression chamber adjacent to a tip of a
piston
at bottom dead center. A tip of a piston at bottom dead center may be located
in a cylinder and/or compression chamber with a distance to a cylinder base
and/or bottom of an associated compression chamber. A linear seal may be
installed circumferentially on a part of a piston positioned within a cylinder
15 and/or compression chamber.
One or more, or all, of the pistons may not comprise any seal such as
for example a piston ring or a piston seal, potentially attached to and/or
mounted on the piston. In an embodiment no seal is attached or mounted on
one or more, or all, of the pistons. Such a seal is typically positioned
between
20 an outer diameter of a piston and the inner wall of the associated
compression
chamber acting to seal therebetween. The movement of a piston being config-
ured such that it does not touch the inner wall of the associated compression
chamber in operation and/or during standstill and the provision of a seal such
as a rod seal and/or shaft seal which is positioned in the cylinder housing
for
25 sealing between the piston and the associated compression chamber may
pre-
vent the piston from contacting and/or wearing on and/or damaging the inner
wall of the compression chamber and ensure adequate sealing of the compres-
sion chamber, particularly towards the crank housing, which may allow the
omission of a seal on the piston such as a piston seal and/or piston ring(s).
30 Additionally or alternatively, the compressor and/or one or more pistons
and/or
one or more cylinders and/or one or more compression chambers and/or one
or more sliding shoes and/or the crankpin and/or one or more bearings
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
positioned on the crankpin and/or one or more guide grooves and/or one or
more guide elements, and/or one or more rod seal(s) included in the cylinder
base may be configured such that, in operation and/or at standstill, at least
one
or each piston do(es) not or substantially not touch or is/are configured to
not
5 or substantially not touch, an inner wall of the associated compression
cham-
ber. Additionally or alternatively, the compressor and/or one or more pistons
and/or one or more cylinders and/or one or more compression chambers and/or
one or more sliding shoes and/or the crankpin and/or one or more bearings
positioned on the crankpin and/or one or more guide grooves and/or one or
10 more guide elements, and/or one or more rod seal(s) included in the
cylinder
base may be configured such that, in operation, at least one or each piston
only
or substantially only move(s) or is/are configured to only or substantially
only
move in the radial direction of the compressor. Hereby, frictional losses from
the piston(s) moving in the compression chamber(s) may be reduced and/or
prevented, which may increase efficiency of the compressor. This may also
reduce wear on the inner wall(s) of the compression chamber(s) and/or a pe-
riphery, potentially a peripheral surface, of the piston(s), thereby extending
ser-
vice intervals and/or lifetime of the compressor.
A "periphery" may be understood as the outer limits and/or edge of an
object. Similarly, a "peripheral surface" may be understood as an outer
and/outermost surface of an object. The periphery of an object may substan-
tially coincide or coincide with a diameter and/or outer diameter and/or outer-
most diameter of the object.
The two or more cylinders may be positioned radially about the rotation
axis. The two or more cylinders may be radial cylinders. The two or more cyl-
inders may be equidistantly spaced around the axis of rotation. The two or
more
cylinders may be equidistantly spaced in the radial direction from the axis of
rotation.
The compressor may comprise cooling channels for cooling the cyl in-
30 ders and/or compression chambers. Each cylinder may comprise one or more
cooling channels for cooling the cylinder and/or compression chamber. The one
or more cooling channels may be interconnected through one or more cooling
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
11
pipes extending between the cylinders. The one or more cooling pipes may
extend externally of the cylinders. The one or more cooling channels and the
one or more cooling pipes may form a cooling circuit for cooling the
cylinders.
Each cylinder may comprise at least one cooling channel with a first direction
5 of
flow and at least one cooling channel with a second direction of flow. The
second direction of flow may be opposite to the first direction of flow. In
this
way a circulating flow of a cooling medium may be provided. The two cooling
channels of each cylinder may be interconnected with two cooling channels of
a preceding and/or a successive cylinder, wherein each cooling channel of
each cylinder is interconnected to a respective cooling channel of a directly
preceding and/or directly following cylinder through a respective cooling
pipe.
In a cylinder defining the first or final compression stage, the at least one
cool-
ing channel with a flow in a first direction and the at least one cooling
channel
with a flow in a second direction may be interconnected to form a loop such
that a cooling medium flow may circulate through the respective cylinder and
to a preceding cylinder.
In an embodiment the multi-stage compressor further comprises at
least one supply compressor for supplying compressed fluid at a pressure
above atmospheric pressure to the compression chamber of the first cylinder
20 and/or
inlet of the multi-stage compressor, wherein the supply compressor and
the pistons is driven by one and the same crankshaft as the pistons of the
multi-
stage compressor. In a development of the previous embodiment the at least
one supply compressor is driven by the one and same crankpin as the pistons
of the multi-stage compressor.
25 The
supply compressor may be a reciprocating compressor and/or a
membrane compressor, and/or a piston compressor. The multi-stage compres-
sor may comprise two, three, four, five, or more supply compressors each sup-
plying compressed fluid at a pressure above atmospheric pressure to the com-
pression chamber of the first cylinder. One or more of the supply compressors
30 may be mounted and/or installed on and/or in and/or inside the multi-stage
compressor. The one or more supply compressors may be positioned and/or
mounted and/or installed at least partly inside the compressor housing. The
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
12
one or more supply compressors may operate in parallel. One or more supply
compressors may be positioned externally of the multi-stage compressor hous-
ing. One or more supply compressors may be positioned circumferentially
around the one and the same crankshaft driving the pistons. One or more sup-
ply compressors may be positioned outside of the multi-stage compressor
housing circumferentially around the one and same crankshaft. Each of the one
or more supply compressors may be driven by one and the same second crank-
pin. The second crankpin may be positioned externally of the multi-stage com-
pressor housing, potentially on the one and same crankshaft driving each pis-
ton.
One or more supply compressors may be positioned within an outer
periphery of the multi-stage compressor. One or more of the supply compres-
sors may be positioned at least partly within or within the multi-stage
compres-
sor housing. One or more of the supply compressors may be attached to re-
spective valve pipe and/or cooling pipes. One or more of the supply compres-
sors may be positioned between, potentially in a spacing between, adjacent
cylinders of the multi-stage compressor. One or more, or each, of the supply
compressor(s), potentially a respective outlet of each of the supply compres-
sors, may be connected to the compression chamber of the first cylinder, p0-
tentially through a respective supply pipe. Each of the supply compressors may
be connected to the inlet of the compression chamber of the first cylinder, po-
tentially through an associated respective supply pipe. One or more of the sup-
ply pipes may flow into one common pipe and/or manifold before entering the
compression chamber of the first cylinder.
Tests show that inclusion of such a supply compressor for corn press-
ing air provides an adequate amount of compressed air to the compression
chamber of the first cylinder with minimal noise from the supply compressor
and minimal impact on the drive unit driving the multi-stage compressor. Equal
results are expected for other gases as well as fluids. In an embodiment a sep-
arate and individual sliding shoe for engaging with the crankpin is attached
to
a bottom end of each piston.
In this way the compressor may be quick to assemble as a connecting
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
13
rod is not required. This may improve efficiency of the compressor as less en-
ergy may be lost to overcome inertia of moving parts and/or friction between
moving parts. Further, the movement of each piston may be kept independent
which may improve design choice and adaptability of the compressor. The bot-
5 tom end of a piston may be an end opposite a top end of the piston. A top
end
of the piston may be positioned within an associated compression chamber. A
top surface of a top end of a piston may compress a fluid in the associated
compression chamber. The bottom end of a piston may be an end of the piston
closest to and/or facing the crankpin and/or the axis of rotation. Each
sliding
10 shoe may be mounted on the bottom end of an associated piston. Each
sliding
shoe may be mounted at the bottom end of an associated piston. Each sliding
shoe may be attached to an associated piston via a connecting shaft extending
through the bottom end of the associated piston and at least one portion of
the
associated sliding shoe. Each sliding shoe may be detachable from their asso-
15 ciated piston. The sliding shoes may be separate parts i.e. individual
parts that
are not connected to each other. Each sliding shoe may engage with the crank-
pin and/or a crankpin bearing attached on the crankpin. The sliding shoes
and/or a sliding surface of the sliding shoes engaging, or for engaging, with
the
crankpin and/or crankpin bearing may comprise and/or be coated with and/or
20 consist of a plain bearing material such as metals, metal alloys, or
polymers
e.g. brass, steel, aluminium or aluminium alloys, bronze, PTFE, and/or combi-
nations thereof. The sliding surface may be shaped form-fittingly to the crank-
pin and/or a crankpin bearing mounted on the crankpin. The sliding surface
may be arc-shaped and/or shaped as part of a circumference of a circle. A
25 sliding surface of a sliding shoe may be a lower and/or bottom surface of a
sliding shoe and/or a surface for facing the crankpin and/or a crankpin
bearing.
A sliding surface of a sliding shoe may be a surface of the sliding shoe for
sliding on the crankpin and/or a crankpin bearing. One or more, or each
sliding
shoe(s) may comprise a sliding surface for engaging with the crankpin and/or
30 a crankpin bearing attached on the crank pin. Said sliding shoe sliding
surface
may be a part for engaging with the crankpin and/or a crankpin bearing at-
tached on the crank pin of a sliding shoe.
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
14
At least one crankpin bearing for engaging with the sliding shoes may
be mounted on the crankpin. The crankpin bearing may be circular. The crank-
pin bearing may be located between the crankpin and the sliding shoes. The
crankpin bearing may be a plain bearing, also known as a sliding bearing or
slide bearing, or may be a roller bearing, or any other suitable bearing. The
sliding shoe may engage with an outer surface of the crankpin bearing. A
roller
bearing may be understood as a bearing with an inner race and an outer race
with rolling elements between the inner race and the outer race. In the case
of
a roller bearing, the outer surface of the bearing may be an outer surface of
an
outer race of the bearing. In the case of a roller bearing a surface of an
inner
race of the bearing may be attached on the crankpin. One sliding shoe may be
attached to and associated with one piston.
In a development of the previous embodiment, each sliding shoe is
rotatably attached to the bottom end of the associated piston.
Each piston having a separate rotating sliding shoe may provide a high
freedom of choice of design as the engagement of each sliding shoe with the
crankpin, and thereby the movement of each piston, may be tailored for each
piston. The sliding shoes may be rotatably attached to the bottom ends of as-
sociated pistons via a bearing such as a plain bearing, roller bearing, or any
other suitable bearing. The sliding shoes and/or the pistons may comprise at
least one bearing and/or bearing surface for supporting the connecting shaft
and allowing a relative rotating motion of the associated sliding shoe and pis-
ton. The bearing surface may be a plain bearing surface. The bearing may be
a plain bearing (also known as a sliding bearing), roller bearing, or the
like.
Each piston may comprise a plain bearing or roller bearing in the bottom end
of the piston for supporting the associated connecting shaft. Each sliding
shoe
may comprise at least one plain bearing and/or roller bearing through which
the
associated connecting shaft extends. The at least one portion of the sliding
shoe through which the associated connecting shaft extends may comprise of
and/or consist of and/or be coated with a plain bearing material such as
metals,
metal alloys, or polymers e.g. brass, steel, aluminium or aluminium alloys,
bronze, PTFE, and/or combinations thereof such that the sliding shoe itself
may
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
constitute a plain bearing for supporting the associated connecting shaft. The
connecting shaft may extend through two such portions of the associated slid-
ing shoe. The connecting shaft may extend in the axial direction. The connect-
ing shaft may be secured to the associated piston and sliding shoe through one
5 or
more circlips, pins, bolts, or the like. The circlips, pins, bolts, or the
like may
be positioned at in the axial direction opposite ends of the connecting shaft.
In an embodiment, a housing of the multi-stage compressor comprises
at least one guide groove, the at least one guide groove being configured for
guiding the movement of at least one guide element attached to a piston.
10 This
may provide freedom of choice of design of compression cham-
ber and associated piston diameters as the walls of the compression chambers
need not be configured to guide the pistons. The compressor may comprise at
least one guide groove per piston for guiding the movement of at least one
guide element attached to the associated piston and/or sliding shoe. The guide
15 groove may be offset in the axial direction from the pistons. The at least
one
guide groove may extend in the radial direction. The at least one guide groove
may extend a length equal to a length of a stroke length of an associated
piston.
The at least one guide element may be attached to a connecting shaft. The
housing of the compressor may comprise at least two guide grooves per piston,
the at least two grooves being offset in the axial direction either side of
the
piston and/or sliding shoe. Each piston and/or sliding shoe may comprise one
or more guide elements for being guided in a guide groove. Each guide element
may be guided in a separate guide groove. Two guide elements may be at-
tached to a piston and/or sliding shoe, wherein the two guide elements are
offset in the axial direction either side of the piston and/or sliding shoe.
Two
guide elements may be attached to in the axial direction opposite ends of a
connecting shaft. Thereby the movement of each piston may be guided. The
guide elements may comprise and/or consist of metal or a plain bearing mate-
rial such as described herein. The guide elements may be secured to the con-
necting shaft via clips such as circlips. The pistons may be guided such that
the one or more pistons do not touch an inner wall of the associated compres-
sion chamber and/or such that the one or more pistons only move in the radial
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
16
direction. This may have the advantages as explained above.
The at least one guide groove and/or the at least one guide element
attached to a piston may be configured such that, in operation, the associated
piston does not touch an inner wall of the associated compression chamber
5 and/or such that, in operation, the piston only or substantially only
move(s) in
the radial direction of the compressor.
In an embodiment, the multi-stage compressor comprises one or more
linear bearing(s) configured for guiding the movement of an associated piston
of the pistons of the multi-stage compressor and/or at least one guide element
attached to the associated piston.
The linear bearing may be a slide bushing, a plain bearing, a ball bear-
ing, or the like. The multi-stage compressor may comprise 1, 2, 3, 4, 5, 6, or
more linear bearings per piston for guiding the movement of an associated pis-
ton and/or at least one guide element attached to the associated piston. Each
linear bearing may guide one guide element attached to the associated piston.
Additionally or alternatively, the guide element attached to the associated
pis-
ton may comprise one or more linear bearings. Each linear bearing may slide
on a journal and/or a shaft attached in or to the compressor housing. The jour-
nal and/or shaft may extend parallel to the associated piston and/or the move-
ment direction of the associated piston. The at least one guide element may
comprise two linear bearings each sliding on a journal and/or shaft attached
in
and/or to the multi-stage compressor housing.
Additionally or alternatively, the multi-stage compressor may comprise
1,2, 3, 4, 5, 6, or more bushing guide bars per piston configured for guiding
the
25 movement of an associated piston. The bushing guide bar(s) may be
positioned
and/or attached in the compressor housing and/or cylinder housing and/or com-
pression chamber, potentially to form an innermost surface of the compression
chamber. The innermost surface of the compression chamber may face the
associated piston and potentially provide a surface for a piston to slide
against.
The bushing guide bar(s) may be made of a bushing material. The bushing
guide bar(s) may extend parallel to the associated piston and/or the movement
direction of the associated piston. The bushing guide bar(s) may alternatively
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
17
be denoted bushing guide rod(s). The bushing guide bar(s) may extend in the
axial direction of the associated piston and may be positioned around the cir-
cumference of the associated piston.
Additionally or alternatively, the multi-stage compressor may comprise
5 1,2, 3, 4, 5, 6, or more guide rollers configured for guiding the
movement of an
associated piston. The guide rollers may be positioned and/or attached and/or
installed and/or mounted in the multi-stage compressor housing and/or cylinder
housing. A guide rollers may rollingly guide the movement of the associated
piston. The guide roller(s) may be positioned along the axial direction of the
associated piston and may be positioned around the circumference of the as-
sociated piston.
In an embodiment, the compression chamber of at least a first cylin-
der of the two or more cylinders is connected to the compression chamber of a
second cylinder through at least one non-return valve for preventing flow of
15 fluid from the compression chamber of the second cylinder to the
compression
chamber of the first cylinder.
In this way, fluid may flow from the compression chamber of a given
cylinder to the compression chamber of a directly following cylinder i.e. from
a
first compression stage to the next compression stage of the multi-stage com-
20 pressor and at flow from a given compression chamber to a compression
cham-
ber of a cylinder of a preceding compression stage may be prevented. This
may reduce complexity of construction of the compressor as just a single flow
channel with a non-return valve between compression chambers of two cylin-
ders may be needed. A compression chamber of a cylinder may be connected
25 to a compression chamber of a directly following and/or directly
preceding cyl-
inder through at least one non-return valve. The compression chambers of the
cylinders may be connected by non-return valves preventing flow of fluid from
a compression chamber of a given cylinder to a compression chamber of a
directly preceding cylinder. The at least one non-return valve may prevent
fluid
30 from flowing from a given cylinder to a directly preceding cylinder_ A
non-return
valve may be provided between each compression chamber and the compres-
sion chamber of the directly following cylinder and/or directly preceding
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
18
cylinder. The at least one non-return valve may also be denoted a check valve.
The at least one non-return valve may be spring loaded. The at least one non-
return valve may be a ball check valve, diaphragm check valve, swing check
valve, or any other suitable valve. The compression chamber of a final
cylinder
5 i.e. the final stage of compression may be connected to the outlet of the
com-
pressor. The compression chamber of a final cylinder may be connected to the
outlet of the compressor through at least one non-return valve. The inlet of
the
compressor may be connected to the compression chamber of a first cylinder
i.e. the first compression stage of the compressor through at least one non-
return valve. In this way a compressed fluid may pass from the inlet and suc-
cessively through the compression chambers of the successive cylinders to,
and out of, the outlet, and flow of fluid from the outlet through preceding
com-
pression chambers of preceding cylinders may be prevented. The non-return
valve may be located externally of the two or more cylinders. The non-return
valve may be located in a valve housing that is attachable to and detachable
from a cylinder and/or cylinder housing and/or compressor and/or compressor
housing.
In an embodiment, the at least one non-return valve is located exter-
nally of the two or more cylinders inside a valve pipe such that a fluid
flowing
from the compression chamber of at least a first cylinder to the compression
chamber of a second cylinder flows through the valve pipe and the at least one
non-return valve.
The term "located externally of the two or more cylinders" throughout
this disclosure may be understood as not being located in or within a cylinder
25 and/or cylinder housing of the two or more cylinders.
In this way there may be a high freedom of choice of design of the
compressor, particularly the cylinders and cylinder housings as the connection
of the compression chambers as well as the non-return valves may be provided
separately and/or externally of the cylinders or a housing thereof. A valve
pipe
30 may constitute a part of a compression chamber. A compression chamber
may
comprise at least a part of a valve pipe. The valve pipe may comprise a pipe
volume for the fluid to flow through either side of the non-return valve. The
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
19
compression chamber may comprise a pipe volume of a valve pipe. The com-
pression chamber may be directly connected to a pipe volume. The valve pipe
may be a cylindrical pipe. The, or a, valve pipe may extend between a given
cylinder and a directly following cylinder or a preceding cylinder. A valve
pipe
may be provided between each compression chamber and the compression
chamber of a directly following cylinder and/or directly preceding cylinder. A
or
one or more, potentially all valve pipe(s) may be positioned within an outer
cir-
cumferential periphery of the compressor and/or cylinder(s) and/or cylinder
housing(s). A or one or more, potentially all valve pipe(s) may be positioned
closer to a center and/or the rotation axis of the compressor than an
outermost
part of a or the cylinder(s) and/or cylinder housing(s). Said outermost part
of
the cylinder(s) and/or cylinder housing(s) potentially being a part of the
cylin-
der(s) and/or cylinder housing(s) positioned farthest away from the center
and/or the rotation axis of the compressor. The at least one non-return valve
may be positioned inside the valve pipe halfway along a length the valve pipe
extends between a given cylinder and a directly following cylinder. The valve
pipe may comprise an inlet end and an outlet end. The valve pipe may have a
valve pipe length extending between the inlet end of the valve pipe and the
outlet end of the valve pipe. One or more, potentially all, valve pipe(s) may
be
substantially straight or straight. The term "straight" may be understood as
the
pipe extending substantially only or only in one direction. One or more, or
all,
valve pipe(s) may substantially extend or extend between an outer side wall of
a given cylinder and/or cylinder housing and an outer side wall of directly
fol-
lowing or preceding cylinder and or cylinder housing. A valve pipe may extend
substantially straight and/or straight between said respective outer side
walls.
A, or one or more, or each, or all valve pipe(s) may extend substantially
straight
and/or straight between outer side walls of directly following and/or directly
pre-
ceding cylinders and/or cylinder housing(s). The at least one non-return valve
may prevent flow of fluid in a direction from the outlet end to the inlet end
of the
valve pipe. A first pipe volume may be a pipe volume extending from an inlet
end of the valve pipe to the non-return valve. A second pipe volume may be a
pipe volume extending from the non-return valve to the outlet end of the valve
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
pipe. At least one compression chamber may comprise a first pipe volume. The
non-return valve may be positioned nearer the inlet end of the valve pipe than
the outlet end of the valve pipe. The non-return valve may be positioned less
than 1/100, 1/75, 1/50, 1/40, 1/30, 1/25, 1/20, 1/15, 1/10, 1/9, 1/8, 1/7,
1/6, 1/5,
5 1/4, 1/3 of a valve pipe length from the inlet end of the valve pipe. The
at least
one non-return valve may be positioned inside the valve pipe equidistantly
from
the inlet end and the outlet end. The valve pipe may comprise a sealing
element
at its inlet end and/or outlet end for sealing against a housing of a
cylinder. The
inlet end and/or outlet end of the valve pipe may be rounded and/or spherical.
10 The cylinder housing may comprise openings corresponding to the shape of
the inlet end and/or outlet end of the valve pipe to receive the inlet end
and/or
outlet end. In this way the valve pipe may be conveniently attached to or re-
moved from a housing of a cylinder of the compressor. The valve pipe may
comprise a first and a second valve pipe part. The first and second valve pipe
15 parts may be detachable from each other such that the valve pipe may be
dis-
assembled into a disassembled state where the first and second valve pipe
parts are disconnected. The first and second valve parts may be attachable to
each other into an assembled state where the first and second valve pipe parts
are connected. The first and second valve pipe parts may be attached to each
20 other via a thread. The first valve pipe part may comprise a thread
matching a
thread on the second valve pipe part for assembly and disassembly of the first
and second valve pipe parts. The first and second valve pipe parts may each
constitute one half of the valve pipe. A sealing element may be disposed be-
tween the first and second valve pipe parts in the assembled state. The valve
25 pipes may be cooled by a cooling device. A cooling device such as a
cooling
jacket for cooling the valve pipe may attached to the valve pipe. The cooling
device may be disposed around the valve pipe. The cooling jacket may be con-
nected to one or more cooling pipes. The cooling pipes may be connected to
one or more cooling channels. The cooling jacket may be connected to one or
30 more cooling channels. In this way the cooling jacket may be part of the
cooling
circuit of the compressor and both the two or more cylinders and the valve
pipes
may be cooled. The cooling jacket and connected valve pipes and/or connected
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
21
cooling channels may form a cooling circuit that is separate of the cooling
circuit
for cooling the cylinders. In the disassembled state of the valve pipe the at
least
one non-return valve may be exposed. The at least one non-return valve may
be seated in the first and/or second valve pipe part. The at least one non-
return
valve may be detachably attached to the first and/or second valve pipe part.
The at least one non-return valve may be threaded into the first or second
valve
pipe part. A non-return valve may be positioned at an inlet end of the valve
pipe(s) and an outlet end of the valve pipe(s). The volume between the non-
return valves at the inlet end and the outlet end of the valve pipe(s) may be
considered a pipe volume. This may provide a buffer for compressed fluid be-
tween compression chambers.
The one or more cooling pipes may extend between the cylinders in
parallel with the valve pipes.
In a development of the previous embodiment, the valve pipe(s) is/are
removably attached between two cylinders.
This may provide a compressor that is easy to maintain and/or adapt
to different use cases, as the valve pipes may be quickly and easily replaced
or swapped for a different version e.g. with a higher rated non-return valve
for
higher pressure applications.
The valve pipe(s) may be removably attached to a cylinder by press
fit, clip in, snap lock and/or threading. The valve pipe(s) may be removably
attached such that the valve pipe(s) may be removed by hand i.e. without use
of a tool. An inlet end and/or outlet end of a valve pipe may be removably at-
tached in a cylinder.
In an embodiment, at least one compression chamber comprises a
first pipe volume of a valve pipe.
In an embodiment, the valve pipe(s) extend between a given cylinder
and a directly following cylinder.
In an embodiment, the valve pipe(s) is/are provided between each
compression chamber and the compression chamber of a directly following cyl-
inder and/or directly preceding cylinder.
In an embodiment, one or more, potentially all, valve pipe(s) is/are
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
22
substantially straight.
In an embodiment, one or more, potentially all valve pipe(s) is/are po-
sitioned within an outer circumferential periphery of the compressor and/or
cyl-
inder(s) and/or cylinder housing(s).
5 In an embodiment, one or more, potentially all valve pipe(s) are
posi-
tioned closer to a center and/or a rotation axis about which the crankpin
rotates
than an outermost part of a or the cylinder(s) and/or cylinder housing(s).
In an embodiment, one or more of the valve pipe(s) extend(s) substan-
tially straight and/or straight between outer side walls of directly following
10 and/or directly preceding cylinders and/or cylinder housing(s).
In an embodiment, one or more of the pistons are of different diame-
ters.
In this way the compressor may be tailored to specific use cases as
piston and/or cylinder diameters may be chosen for the compressor to deliver
15 the required pressure output from a given pressure input.
In an embodiment, for at least one cylinder a cylinder housing com-
prising the associated compression chamber of the given cylinder is detachable
from and attachable to the compressor.
In this way the compressor may be simple to maintain and/or adapt to
20 a specific use case as cylinder housings may be quickly swapped or replaced
with a different cylinder housing with e.g. a different diameter compression
chamber in order for compressor to deliver a desired pressure output.
The cylinder housing may be detachable from and attachable to a cyl-
inder base. The cylinder base may include a linear seal such as a piston seal
25 and/or rod seal for sealing between the associated piston and cylinder. At
least
one, two, three, four, five, six, or more cylinder bases may include a linear
seal
such as a rod seal for sealing between the associated piston and cylinder. The
rod seal may have a height extending in the radial direction of the compressor
equal to or less than 1/2, 9/20, 2/5, 7/20, 3/10, 1/4, 1/5, 3/20, 1/10, 1/20
of the
30 stroke length of the associated piston The height of the rod seal may
extend
in parallel to the length of the associated piston. A rod seal may
alternatively
be denoted shaft seal. One or more, potentially all, cylinder base(s) may be
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
23
attached, potentially detachably attached to the compressor housing.
At standstill and/or in operation of the compressor, one or more of the
pistons may substantially only or only contact the associated linear seal such
as a rod seal. The associated linear seal may be included in the associated
cylinder base and/or comprised by the associated cylinder. At standstill
and/or
in operation of the compressor, two or more of the pistons may substantially
only contact or only contact the associated linear seal included in the
cylinder
base and/or comprised by the cylinder. At standstill and/or in operation of
the
compressor, all pistons may substantially only contact or only contact the as-
sociated linear seal such as a rod seal. Said associated linear seal
potentially
being included in the cylinder base and/or comprised by the cylinder.
Experiments have shown that a rod and/or shaft seal located in the
cylinder housing perform better at higher pressures than seals located on the
piston. This may be due to the larger amount of space available for rod and/or
shaft sealings located in the cylinder housing in both the radial and axial
direc-
tion of the piston compared to seals such as piston rings located on the
piston.
This may provide a greater choice of size, material, and/or shape of the seal.
This may facilitate reduced friction and/or an improved seal during operation
of
the compressor.
In an embodiment, the compression chambers of one or more of the
cylinders are of different diameters.
In this way the compressor may be tailored and/or configured for a
particular use case as compression chamber diameters may be chosen for the
compressor to deliver the required pressure output from a given pressure
input.
Each compression chamber of the two more cylinders may be of a
different diameter. The pistons may be of a diameter corresponding to the di-
ameter of the respective compression chamber.
In an embodiment, each sliding shoe is secured to the crankpin by an
associated separate annular holding ring which encloses a circumference of
the crankpin.
In this way engagement of the sliding shoes and crankpin may be se-
cured as the sliding shoe may be held to the crankpin. Furthermore, it may
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
24
improve the freedom of choice of design of the compressor including cylinders,
compressions chambers, pistons, sliding shoes etc. as holding rings may be
individually configured and designed.
The term "separate" may be understood as not forming part of other
components i.e. being a distinct part in itself.
Additionally or alternatively, the holding rings may enclose a circum-
ference of a holding ring bearing mounted on the crankpin. The holding rings
may grip the circumference of the crankpin and/or circumference of a holding
ring bearing mounted on the crankpin. The holding rings may directly contact
the circumference of the crankpin. The holding rings may be located on a hold-
ing ring bearing mounted on the crankpin. The holding ring bearing may be a
plain bearing or a roller bearing such as described herein. The holding rings
may be secured to the crankpin between two bearings mounted on the crank-
pin. Each, or one or more, sliding shoe(s) may comprise a recess or opening
for receiving a holding ring. The recess or opening for receiving the holding
ring
may be located in and/or extend through the sliding surface. The holding rings
may be attached in an opening of the associated sliding shoe. The holding
rings
may extend through an opening of the associated sliding shoe. The holding
rings may be detachable from the associated sliding shoe. The holding rings
may be attached to the associated sliding shoe via one or more bolts, screws,
clips, pins, and/or clasps. The holding rings may be rigidly attached to the
slid-
ing shoes i.e. such that relative movement of the associated holding ring and
sliding shoe is prevented. The holding rings may comprise, consist of, and/or
be coated with the same material as the crankpin and/or sliding shoes. Each
sliding shoe may comprise a threaded hole for receiving a bolt or screw for
securing an associated holding ring to the sliding shoe. Each holding ring may
comprise a through hole for receiving a bolt or screw. Each holding ring may
comprise a threaded through hole for receiving a bolt or screw. The holding
rings may comprise, consist of, and/or be coated with a plain bearing material
such as e.g metals, metal alloys, or polymers e.g brass, steel, aluminium or
aluminium alloys, bronze, PTFE, and/or combinations thereof. Additionally or
alternatively, the holding ring bearing may be two or more holding ring
bearings.
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
The holding ring bearing(s) may be separate from the one or more crankpin
bearings. The holding ring bearing(s) may be located between two bearings
mounted on the crankpin i.e. crankpin bearings. The holding ring bearing(s)
may have a smaller outer diameter than the one or more crankpin bearings.
5 The holding rings may abut each other. In this way the compressor may be
made more compact. By making the holding rings out of a bearing material the
frictional force between them may be reduced, thereby improving the efficiency
of the compressor. Furthermore, the holding rings abutting each other may en-
sure that the holding rings do not move axially on the holding ring bearing(s)
10 and/or crankpin and may further improve stability of the movement of
the pis-
tons. The holding rings may be positioned between two crankpin bearings two
abut the two bearings. In other words, the holding rings may be sandwiched
between two crank bearings. This may help to further ensure that the holding
rings to do not move axially on the crankpin and/or holding ring bearing(s)
and
15 further improve the stability of the movement of the pistons. Using
axial-radial
bearings as the crankpin bearings may reduce the friction against movement
of the holding rings sandwiched between the crankpin bearings.
In a development of the previous embodiment, the holding rings are
located on a bearing mounted on the crankpin.
20 In this way energy lost to friction between moving parts may be re-
duced as the bearing may lower the friction between the holding rings and the
crankpin.
In an embodiment, the holding ring(s) enclose a circumference of a
holding ring bearing mounted on the crankpin.
25
In an embodiment, the holding rings grip the circumference of the hold-
ing ring bearing.
In an embodiment, the holding rings are secured to the crankpin be-
tween two bearings mounted on the crankpin.
In an embodiment, one or more sliding shoe(s) comprise(s) a recess
or opening for receiving a holding ring.
In development of the previous embodiment, the recess or opening for
receiving the holding ring is located in and/or extends through a sliding
surface
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
26
of the one or more sliding shoe(s) for engaging with the crankpin and/or a
crankpin bearing.
In an embodiment, the compressor is configured such that, in opera-
tion and/or at standstill, at least one or each piston do(es) substantially
not
5 touch an inner wall of the associated compression chamber.
In an embodiment, the compressor is configured such that, in opera-
tion, at least one or each piston only or substantially only move(s) in the
radial
direction of the compressor.
In an embodiment, the at least one guide groove and/or the at least
10 one guide element attached to a piston is/are configured such that, in
operation,
the associated piston does not touch an inner wall of the associated compres-
sion chamber and/or such that, in operation, the piston only or substantially
only move(s) in the radial direction of the compressor.
In an embodiment, the first cylinder comprises one or more associated
15 rod seals for sealing against an associated piston of the first
cylinder.
In an embodiment, a cylinder base of the first cylinder comprises an
associated rod seal for sealing between the first cylinder and its associated
piston.
In an embodiment, the rod seal has a height extending in the radial
20 direction of the compressor, said height being equal to or less than 1/2 of
a
stroke length of the associated piston.
In an embodiment, at standstill and/or in operation of the compressor,
the associated piston of the first cylinder substantially only contacts the
asso-
ciated rod seal of the first cylinder.
25 In an embodiment, the pistons do not comprise any seal, such as for
example a piston ring or a piston seal, potentially attached to and/or mounted
on the piston.
In an embodiment, the crankpin and/or a crankpin bearing(s) provided
on the crankpin has/have an outer diameter that is at least 1.1 times a
smallest
30 and/or largest stroke length of each of the pistons.
In an embodiment, a length of a lever arm acting on a rotation axis
about which the crankpin rotates is equal to or less than 200% of a smallest
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
27
and/or largest stroke length of each of the pistons.
In an embodiment the compressor comprises a rotatable crankshaft
comprising at least two interconnected separate shafts extending in parallel
with the crankpin, wherein the crankpin interconnects the two of the at least
two
5
interconnected shafts by being clamped to a respective end of each of the two
shafts by a detachable clamp mechanism.
In this way the compressor may be easy to disassemble as the crank-
pin and crankshaft may be disassembled from each other. This may improve
serviceability. Further still, it may allow the compressor to be adapted to
differ-
ent use cases, by interchanging parts.
In an additional or alternative embodiment, at least one sliding shoe is
rotatably attached to an associated piston via a connecting shaft extending
through the sliding shoe and the associated piston, wherein at least one guide
element configured for being guided in the at least one guide groove is
attached
to the connecting shaft.
In this way the drive and movement of the piston may be guided and
secured by the at least one guide element in the at least one guide groove.
The compressor may have a largest dimension equal to or less than
5, 4.5, 4, 3.5, 3, 2.5,2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1,0.9,
0.8, 0.7,
0.6, 0.5, 0.4, 0.3. 0.2, or 0.1 meter. The largest dimension may be a largest
dimension of the compressor extending in the radial direction of the
compressor
or the axial direction of the compressor.
A second aspect of the invention concerns a method for compressing
a fluid in a multi-stage compressor, the compressor comprising:
25 two or
more cylinders, each cylinder having a compression chamber
and a piston, so that a fluid in each of the compression chambers is com-
pressed by the associated piston;
the cylinders being connected in series such that a fluid entering an
inlet of the compressor is compressed to a first pressure in the compression
30
chamber of a first cylinder and, then, enters into the compression chamber of
a second cylinder where the compressed fluid is compressed to a second
higher pressure; and
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
28
wherein each piston is driven by one and the same crankpin of the
corn pressor.
If more than two cylinders are present, the fluid successively enters
into and is compressed to a successively higher pressure in the compression
5
chamber(s) of the additional cylinder(s), before the fluid exits from an
outlet of
the compressor.
In an embodiment, the multi-stage compressor further comprises at
least one supply compressor supplying compressed fluid at a pressure above
atmospheric pressure to the compression chamber of the first cylinder, wherein
the supply compressor and the pistons is driven by one and the same crank-
shaft, potentially the one and same crankpin, as the pistons of the multi-
stage
corn pressor.
In a third aspect, the invention concerns a system for compressing a
fluid, the system comprising:
15 - a
multi-stage compressor according to the first aspect of the invention
and
- a second compressor configured to provide fluid at a pressure above
atmospheric pressure to the inlet of the multi-stage compressor and/or the com-
pression chamber of the first cylinder.
20 In an
embodiment, the second compressor is a stationary or fixed com-
pressor.
A stationary or fixed compressor may be understood as a compressor
that is installed and/or mounted and/or fixed to a location, and which has to
be
uninstalled and/or unmounted to be moved from said location. The second
25
compressor may be a compressor supplying a compressed air system and/or
air line and/or air piping system such as may be used in a workshop, factory,
and/or industrial plant.
In an embodiment, the second compressor is comprised by and/or part
of the multi-stage compressor.
30 In an
embodiment the system further comprises one or more compo-
nents selected from the following list: a gas filter and/or a fluid filter
and/or a
cooling device and/or a cooling fluid tank and/or a power supply and/or a
power
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
29
generator, and/or a drive unit for driving the multi-stage compressor, and/or
a
compressed fluid tank, wherein, in the given case, the multi-stage compressor
is connected the fluid tank for supplying compressed fluid to the compressed
fluid tank.
5 The compressed fluid tank may be a compressed liquid tank or a com-
pressed gas tank, such as an air tank. The gas filter may be carbon filtering
device (clean air)
The cooling device may be a cryogenic cooling device also known as
a cryocooler. The power generator may be for supplying power to a given ap-
plication such as the drive unit for driving the multi-stage compressor and/or
other external applications. The power generator may be driven by a sustaina-
ble energy source such as solar, wind, hydro, and/or surplus energy, or the
like.
This may contribute to sustainability and reduction of CO2 emissions (CO2
neutrality), especially when the power generator is driven by energy from
15 sources in the above. The system may optionally furthermore comprise a
con-
tainer in which one or more of the components of the system are placed. In an
embodiment the power generator is a compressed air driven power generator.
The power generator may be driven by compressed air from the compressed
air tank supplied by the multi-stage compressor and/or directly from the multi-
stage compressor.
In an embodiment, the multi-stage compressor is a portable compres-
sor. In an embodiment, the second compressor is a multi-stage compressor
according to according to the first aspect of the invention.
In an embodiment, the second compressor is a supply compressor for
supplying compressed fluid at a pressure above atmospheric pressure to the
compression chamber of the first cylinder, wherein the supply compressor and
the pistons is driven by one and the same crankshaft, potentially the one and
same crankpin, as the pistons of the multi-stage compressor.
In an embodiment, the multi-stage compressor and the second corn-
30 pressor are powered by the same drive unit.
The crankshafts of the multi-stage compressor and the second com-
pressor may be coupled together to transmit drive between the compressors.
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
Two, three, four, five or more compressors may be powered by the same drive
unit. The crankshafts of the two, three, four, five or more compressors may be
coupled together. Additionally or alternatively, the multi-stage and second,
third, fourth, fifth or more compressors may share a common crankshaft. Two,
5 three, four, five or more compressors according to the present invention may
be connected in series or parallel. An additional compressor, potentially a
multi-
stage compressor according to the first aspect of this invention, may be con-
nected to each of compressors connected in parallel or to a first of the com-
pressors connected in series. The single additional compressor may provide a
10 fluid at a pressure above atmospheric pressure to the inlet of the
associated
corn pressor(s).
In a fourth aspect, the invention concerns use of a multi-stage com-
pressor according to the first aspect of the invention and/or a system
according
to the third aspect of the invention for energy storage.
15 In an embodiment, the energy storage is compressed-fluid energy
storage
The fluid may be air, water, fossil fuels such as fossil fuel gasses
and/or liquids. The compressor may be used for filling compressed air tanks
with compressed air for use in pumping tires, powering air rifles, filling gas
tanks
20 e.g. oxygen or other gas tanks, powering generators for
production of electric-
ity, powering machinery, powering air motors in applications such as vehicles,
workshops, factories, industrial plants and the like. Additionally or
alternatively,
the compressor may be used for providing compressed liquid e.g. water for
industrial applications such as cutting of different materials with the com-
25 pressed liquid, powering generators for production of electricity, driving
ma-
chinery.
In an embodiment, the invention concerns use of a multi-stage com-
pressor according to the first aspect of the invention and/or a system
according
to the third aspect of the invention for energy storage for storing compressed
30 fluid for driving a power generator.
In an embodiment, the invention concerns use of a multi-stage com-
pressor according to the first aspect of the invention and/or a system
according
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
31
to the third aspect of the invention for energy storage compressed gas, poten-
tially compressed air, storage.
In an embodiment, the invention concerns use of a multi-stage com-
pressor according to the first aspect of the invention and/or a system
according
5 to the third aspect of the invention for compressing a fluid.
In an embodiment, the invention concerns use of a multi-stage com-
pressor according to the first aspect of the invention, wherein the multi-
stage
compressor is connected to a second compressor.
In an embodiment the second compressor provides fluid at a pressure
10 above atmospheric pressure to the inlet of the multi-stage compressor.
In an embodiment the second compressor is a stationary or fixed com-
pressor installation.
In a development of the previous embodiment, the stationary or fixed
compressor installation is installed in a gas station, workshop, garage, or
build-
15 ing.
In an embodiment, the invention concerns use of a multi-stage com-
pressor according to the first aspect of the invention and/or a system
according
to the third aspect of the invention for charging an air-driven gun, rifle,
bow or
the like.
20 In an embodiment, the invention concerns use of a multi-stage com-
pressor according to the first aspect of the invention and/or a system
according
to the third aspect of the invention for charging a hydraulic or pneumatic
damper, spring, suspension system or the like.
In an embodiment, the invention concerns use of a multi-stage corn-
25 pressor according to the first aspect of the invention and/or a system
according
to the third aspect of the invention for filling a fluid tank or air tank,
tire, an
inflatable, inflatable device, or the like.
A person skilled in the art will appreciate that any one or more of the
above aspects of this disclosure and embodiments thereof may be combined
30 with any one or more of the other aspects and embodiments thereof
In the following, non-limiting exemplary embodiments will be de-
scribed in greater detail with reference to the drawings, in which:
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
32
Fig. 1 shows a perspective view of the front side of the assembled
multi-stage compressor,
Fig. 2 shows a perspective view of the rear side of the compressor in
F ig. 1,
5 Fig. 3 shows a side view of the compressor in Fig. 2,
Fig. 4 shows a section view along line A-A of the compressor in Fig. 3,
Fig. 5 shows a partially exploded view of the compressor in Fig. 1,
Fig. 6 shows an enlarged detail view of the crankpin, piston, and sliding
shoe assembly of the compressor in Fig. 5, and
10 Fig. 7 shows an exploded view of the crankpin and piston assembly
seen in Fig. 6,
Fig. 8 shows the multi-stage compressor with an alternative embodi-
ment of the cooling pipes and cooling jacket,
Fig. 9 shows an embodiment of the multi-stage compressor compris-
15 ing supply compressors,
Fig. 10 shows a cross-section through the multi-stage compressor in
Fig. 10 corresponding to the cross-section shown in Fig. 4,
Fig. 11 shows a close up of the cross-section of a supply compressor
from Fig. 10,
20 Fig. 12 shows an alternative piston movement guide,
Fig. 13 shows a second alternative piston movement guide, and
Fig. 14 shows a third alternative piston movement guide.
Starting with Fig. 1 a multi-stage compressor 1 according to the pre-
sent invention is seen from the front. The compressor 1 comprises three cylin-
25 ders 2a, 2b, 2c each with a cylinder housing 22. The cylinders are intercon-
nected by valve pipes 7 which in this embodiment have cooling jackets 71 for
cooling the valve pipes 7 attached to them. Extending in parallel to the valve
pipes 7 are cooling pipes 26 for cooling the cylinders 2a, 2b, 2c. The cooling
pipes 26 connect cooling channels (not shown) in the cylinder housings 22 to
30 allow a flow of cooling medium for cooling the cylinders 2a, 2b, 2c to flow
through the compressor 1. The compressor 1 further comprises an inlet 12 for
fluid to enter a first cylinder of the compressor 1 and an outlet 13 for
exiting a
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
33
final cylinder of the compressor 1. The fluid supplied to the inlet 12 of the
com-
pressor 1 may be pressurized or pre-compressed such that the fluid being com-
pressed in the first cylinder 2a is already pressurized before being
compressed
in the cylinder. For example the fluid supplied to the inlet may be
pressurized
to 8 bar as in the present example. The compressor further has a crankshaft 6
which comprises two interconnected separate shafts 61. One of the shafts 61
is configured for being connected to a drive unit for driving the compressor
61
i.e. rotating the crankpin 5 and the other shaft 61 exiting the rear side of
the
compressor is optionally configured for being connected to and drive a second
compressor.
Moving to Fig. 2 where the compressor 1 is seen from the rear side,
the guide elements 33 for guiding the movement of pistons 3 are seen guided
in guide grooves 15. As can be seen in Fig. 1 and 2, the majority of
components
of the compressor 1 are connected to each other via bolts 16 e.g. the compres-
sor housing 11, cylinder housings 22, inlet 12, outlet 13, and shield plate
17.
This allows easy assembly/disassembly as well as maintenance and swapping
of components to suit different use cases. In Fig. 3 the compressor 1 is seen
from a side, where it can be seen that the two interconnected shafts 61 of the
crankshaft 6 are concentric and extend an equal length from the compressor
housing 11.
Moving to Fig. 4 a section view of the compressor 1 along line A-A in
Fig. 3, where the sliding shoes have been removed, is shown. Here the com-
pression chambers 21 in the cylinders 2a, 2b, 2c and the associated
cylindrical
pistons 3 can be seen. The cylinders 2a, 2b, 2c are located about the rotation
axis RA and extend in a radial direction away from rotation axis RA. The com-
pression chambers 21 which are located within the cylinders are of different
diameters with the associated pistons 3 having a corresponding diameter d i.e.
the pistons 3 are of diameters corresponding to the diameter of the associated
compression chambers 21. In this way the compressor 1 is tailored to deliver a
fluid at a certain output pressure at the outlet 13 of Fig 1 from a fluid
entering
the inlet 12 of Fig. 1 at a given input pressure.
When the crankshaft 6 is driven and thereby rotated, the crankpin 5 is
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
34
rotated about the rotation axis RA whereby the pistons 3 are driven in and out
of the associated compression chamber 21 to compress a fluid therein. As is
more clearly seen in Fig. 6, the driving in and out of the pistons 3 is
achieved
by the sliding shoes 4 engaging with crankpin bearings 51 mounted on the
5 crankpin 5 and the holding rings 42 enclosing a circumference of a
holding ring
bearing 44 on the crankpin 5. As the crankpin 5 then rotates about the
rotational
axis RA, dependent on its relative position to the pistons, it either pushes
the
pistons 3 into the associated compression chamber by means of the sliding
shoes 4, which engage with the crankpin bearings 51 and which are connected
10 to the pistons 3 via connecting shafts 43, or pulls the pistons 3 out of
the asso-
ciated compression chambers 21 by means of the separate holding rings 42,
which are attached to an associated sliding shoe 4 and secured to the crankpin
by enclosing a circumference of the crankpin 5 and the holding ring bearing
44 mounted on the crankpin 5. It can also be seen how the compression cham-
15 bers 21 of the cylinders 2a, 2b, 2c are connected through non-return
valves 72
to the compression chamber of the directly following cylinder. The respective
chambers are connected through one non-return valve 72 for preventing flow
of fluid from the compression chamber 21 of the given cylinder 2a, 2b, 2c to
the
compression chamber of the directly preceding cylinder. In the shown embod-
20 iment, the non-return valves 72 are located in cylindrical valve pipes 7
which
comprise a pipe volume for fluid to flow through either side of the non-return
valve 72. Thereby, in the embodiment shown, a fluid may enter the compres-
sion chamber 21 of the first cylinder 2a where it is compressed by the associ-
ated piston 3, and, then flows through the flow channel 28 and through the non-
25 return valve 72 in the valve pipe 7 and into the compression chamber 21
of the
second cylinder 2b where the fluid is further compressed by the associated
piston 3 and flows through the next flow channel 28 and through the non-return
valve 72 in the valve pipe 7 into the compression chamber 21 of the third
cylin-
der 2c, where the fluid is even further compressed by the associated piston 3
30 and flows through the outlet 13 of the compressor 1. The spherical inlet
ends
73 and outlet ends 74 of the valve pipes each comprise a sealing element and
are press fit into the cylinder housings 22 of the cylinders 2a, 2b, 2c.
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
The compressor and its components are configured such that in oper-
ation, the pistons 3 move substantially only in the radial direction of the
com-
pressor 1 and in an axial direction of the respective piston 3 in the
compression
chambers 21.
5 In Fig. 4, it can also be seen that the separate annular holding
rings
42 enclose a circumference of a holding ring bearing 44 mounted on the crank-
pin 5. The holding rings 42 are attached to the associated sliding shoes 4 via
a
bolt 16 that extends through the sliding shoe 4 (best seen in Fig. 7) and into
the bolt hole 45 of the associated holding ring 42. For demonstration
purposes,
10 the rotation axis RA is shown in Fig. 4 and Fig. 6, whereby it can be seen
that
the crankpin 5 is positioned with a distance of 0.3 crankpin radii from the pe-
riphery of the crankpin 5 to the rotation axis RA. Furthermore, it can be seen
that cylinders 2a, 2b, 2c comprise rod seals 24 for sealing against their
associ-
ated piston. At standstill and in operation of the compressor, the associated
15 piston 3 each cylinder 2a, 2b, 2c substantially only contacts the
associated rod
seal 24 of each cylinder. The pistons 3 also do not comprise any seal, such as
for example a piston ring or a piston seal attached to and/or mounted on the
piston 3.
Turning to Fig. 5 which shows a partially exploded view of the corn-
20 pressor 1, the manner in which the compressor 1 may be assembled and dis-
assembled, and how components may be swapped out or replaced becomes
apparent. The valve pipes 7 comprise a first and second valve pipe part 7a, 7b
which can be disassembled from each other as shown. The valve pipe parts
7a,7b are attached to each other via a thread, where the non-return valve 72
is
25 seated and threaded into the first valve pipe part 7a. The crankshaft
bearings
62 for supporting the crankshaft 6 in the compressor housing 11 are seen po-
sitioned on shaft 61 of the crankshaft 6. As can also be seen, the cylinder
hous-
ings 22 comprising the associated compression chamber 21 of the given cylin-
der 2a, 2b, 2c is detachable from and attachable to the compressor 1, more
30 specifically from a cylinder base 27.
Fig. 6 shows an enlarged detail view of the crankpin, piston, and sliding
shoe assembly. Each sliding shoe 4 is rotatably attached to an associated
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
36
piston 3 via a connecting shaft 43 extending through the bottom end of the
associated piston 3 and two portions of the associated sliding shoe 4. Each
piston 3 comprises a plain bearing 46 positioned in the bottom end of the
piston
3 for supporting the associated connecting shaft. Each piston 3 has a length
5 "L" extending in the radial direction from a top surface of a top end to
a bottom
surface of a bottom end of the piston. The sliding shoes 4 are made of bronze,
whereby the sliding shoe 4 itself may constitute a plain bearing for
supporting
the associated connecting shaft 46. The connecting shafts 43 extend in the
axial direction and are secured to the associated piston 3 and sliding shoe 4
10 through two circlips 45 positioned at in the axial direction opposite
ends of the
connecting shaft 43. Two guide elements 33 are also attached to in the axial
direction opposite ends of the connecting shaft 43 and secured to the connect-
ing shaft by the circlips 45. A distance D from the center axis CA (Fig. 6) of
the
crankpin 5 to the rotational axis RA is about 1 crankpin radii. Two crankpin
15 bearings 51 for engaging with the sliding shoes 4 are mounted on the
crankpin
5.
As is best seen in Fig. 7, the sliding shoes 4 comprise a sliding surface
41 which is shaped form-fittingly to the crankpin bearings 51 for engaging
with
the crankpin bearings 51. The sliding surface 41 further has an opening 47 for
20 receiving the holding rings 42 which are secured therein by a bolt 16
extending
through the associated sliding shoe 4 and into bolt hole 48.
Fig. 8 shows an alternative embodiment of the cooling pipes 26 and
cooling jacket 71. In this embodiment some of the cooling pipes 26 which are
connected to the cooling channels (not shown) in the cylinders 2a, 2b, 2c con-
25 nect to the cooling jackets 71 and enter into the cooling jacket 71 such
that the
valve pipes 7 and the fluid therein can be cooled. In this way the cooling
jackets
71 form a part of the cooling circuit for the cylinders 2a, 2b, 2c, whereby
both
the valve pipes and the cylinders 2a, 2b, 2c can be cooled.
In the shown embodiment, the compressor housing 11, cylinder hous-
30 ing 22, valve pipes 7, cooling jacket 71, cooling pipes 26, and shield
plate 17
are made of aluminium. The cylinder base 27, connecting shafts 43, crankpin
5, crankshaft 6, and clamp mechanism 63 are made of steel, with the pistons
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
37
3 being made of steel with an aluminium core. The sliding shoes 4 are made of
bronze, with the holding rings 42 and guide elements 45 being made of a com-
bination of bronze and steel.
Turning now to Figs. 9 and 10, an embodiment of the multi-stage corn-
pressor 1 further comprising three supply compressors 8 for supplying com-
pressed fluid at a pressure above atmospheric pressure to the compression
chamber 21 of the first cylinder 2a via inlet 12 is shown. Identical or
similar
components have been giving the same references signs as in Figs. 1 to 8. The
supply compressors 8, positioned within an outer periphery of the multi-stage
compressor 1, and the pistons 3 are driven by one and the same crankshaft 6
and crankpin 5. As the crank pin 5 rotates it actuates the supply compressor
arm 81 which in turn actuates a spring loaded piston assembly 82 inside the
supply compressor 8, whereby fluid is compressed to about 8 bar and out of
the outlet 83 and into the inlet of the compressor 1 and the compression cham-
ber 21 of the first cylinder 2a through respective supply pipes (not shown).
The
multi-stage compressor 1 then compresses this fluid as described in the above.
The supply compressors 8 positioned circumferentially around the crankshaft
6 and crankpin 5 and partly inside the multi-stage compressor housing 2 oper-
ate in parallel. Additionally or alternatively, one or more supply compressor
8
may be positioned outside of the multi-stage compressor housing 2 circumfer-
entially around the one and same crankshaft 6, 61 extending externally out of
the compressor housing 2. Each of the one or more supply compressors may
here potentially be driven by one and the same second crankpin. An enlarged
cross-section through a supply compressor 8 is shown in Fig. 11
In the examples shown in Figs. 1 to 11, the movement of the pistons
3 is guided by the guide grooves 15 and the guide elements 3 attached to the
pistons 4 configured such that, in operation and at standstill, the associated
pistons 3 do not touch an inner wall of the associated compression chamber
21 and such that, in operation, the pistons 3 only or substantially only move
in
the radial direction of the compressor 1. The movement of the pistons 3 may
however be guided in other ways such as for example shown in Figs. 12 to 14.
Fig. 12 shows a piston 3 and a guide element 33 comprising two linear
CA 03183200 2022- 12- 16
WO 2022/008018 PCT/D1(2021/050227
38
bearings 9 in the form of slide bushings each sliding along a journal 91 in
the
form of a shaft. The journal 91 can be attached in or to the multi-stage com-
pressor housing 2.
Additionally or alternatively, the multi-stage compressor 1 may corn-
5 prise
a number of bushing guide bars 92 per piston 3 as seen in Fig. 13, in this
case three, configured for guiding the movement of the associated piston 3.
The bushing guide bars 92 can be positioned and attached in the cylinder hous-
ing 22 and the compression chamber 21, to form an innermost surface of the
compression chamber 21 facing the associated piston 3 and potentially provid-
10 ing a
surface for the piston 3 to slide against. The bushing guide bars 92 extend
parallel to the associated piston 3 and the movement direction of the piston
3.
Additionally or alternatively, as shown in Fig. 13 the multi-stage com-
pressor 1 may a number of guide rollers 93, six in this shown case, configured
for guiding the movement of the associated piston 3. The guide rollers 93 are
15 positioned and attached in the multi-stage compressor housing 2 and the cyl-
inder housing 2 to such that they can rollingly guide the movement of the as-
sociated piston 3. The guide rollers 93 are positioned along the axial
direction
of the associated piston 3 and around the circumference of the associated pis-
ton 3.
20 The
multi-stage compressor may further form part of a system com-
prising a gas filter, a fluid filter, a cooling device such as a cryocooler, a
cooling
fluid tank, a power supply, a power generator, a drive unit for driving the
multi-
stage compressor, a compressed fluid tank, wherein, in the given case, the
multi-stage compressor is connected the compressed fluid tank for supplying
25
compressed fluid to the compressed fluid tank. The power generator may sup-
ply power to a given application such as the drive unit for driving the multi-
stage
compressor and other external applications. The power generator may be
driven by a sustainable energy source such as solar, wind, hydro, and/or sur-
plus energy, or the like. The system may furthermore comprise a container in
30 which one or more of the components of the system are placed. The power
generator for example may be a compressed air driven power generator driven
by compressed air from the compressed fluid or air tank supplied by the multi-
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
39
stage compressor and/or may be driven directly from the multi-stage compres-
sor when power for other external applications are needed.
List of Reference Numerals
1 Multi-stage compressor
11 Compressor housing
12 Inlet
13 Outlet
14 Cooling pipes
Guide groove
16 Bolt
17 Shield plate
2a, 2b, 2c Cylinder
21 Compression chamber
22 Cylinder housing
24 Rod seal
Cooling channel
26 Cooling pipe
27 Cylinder base
28 Flow channel
3 Piston
31 Piston top end
32 Piston bottom end
33 Guide element
4 Sliding shoe
41 Sliding surface
42 Holding ring
43 Connecting shaft
44 Holding ring bearing
45 Circlip
46 Bearing
CA 03183200 2022- 12- 16
WO 2022/008018
PCT/D1(2021/050227
47 Opening
48 Bolt hole
5 Crankpin
51 Crankpin bearing
6 Crankshaft
61 Separate shaft
62 Crankshaft bearing
63 Clamp mechanism
7 Valve pipe
7a First valve pipe part
7b Second valve pipe part
71 Cooling jacket
72 Non-return valve
73 Valve pipe inlet end
74 Valve pipe outlet end
8 Supply compressor
81 Actuator arm of supply
compressor
82 Piston assembly of supply
compres-
sor
83 Outlet of supply
compressor
9 Linear bearing
91 Journal
92 Bushing guide bar
93 Guide rollers
RA Rotation axis
CA Center axis of crankpin
Distance from crankpin to rotation
axis
Piston diameter
Piston length
CA 03183200 2022- 12- 16
