Note: Descriptions are shown in the official language in which they were submitted.
CA 02938434 2016-08-08
DOUBLE DIAPHRAGM PUMPS WITH AN ELECTROMAGNETIC DRIVE
BACKGROUND
Field of the Invention:
[0001] This invention relates to a double diaphragm pump for pumping liquids,
the pump being
driven by a combination of electromagnetic coils and permanent magnets or,
alternatively, a
combination of electromagnetic coils, some of which function as permanent
magnets.
Description of the Prior Art:
[0002] Double diaphragm pumps are known and these pumps can have a single
manifold or
dual manifold porting. The drive mechanism of previous double diaphragm pumps
is
pneumatic, mechanical or electromechanical.
Summary of Invention
[0003] A double diaphragm pump comprises a shaft assembly located in a
housing, the shaft
assembly having a shaft with two ends and two diaphragms, there being one
diaphragm at each
end. A pumping chamber is located outside of each diaphragm, there being two
pumping
chambers. The pumping chambers are fluidly connected to one another and each
pumping
chamber has at least one opening to receive and discharge pumpage. The shaft
assembly is
slidable from side to side of the pump from one pumping chamber to the other.
A first
electromagnetic coil is fixedly mounted within the housing and is located
within a piston
assembly between two additional magnets. During operation, the additional
magnets are
oriented with like polarity facing the first electromagnetic coil is the
additional magnets being
affixed to the piston assembly. One of the additional magnets is always spaced-
apart from the
first electromagnetic coil. Buffer fluid fills a void in the housing between
the shaft assembly and
the piston assembly, the piston assembly being sealed to prevent buffer fluid
from contacting
the first electromagnetic coil and the additional magnets. The first
electromagnetic coil is
connected to repeatedly reverse polarity to alternately attract one additional
magnet and repel
the other additional magnet to cause the piston assembly to reciprocate with
the additional
magnets as the first electromagnetic coil remains fixed. The reciprocation of
the piston
assembly exerts pressure on the buffer fluid to cause the shaft assembly to
reciprocate, the
shaft assembly alternately exerting pressure on one pumping chamber while
releasing pressure
on the other pumping chamber, with check valves, seals and inlet/discharge
ports to facilitate
pumping action.
CA 02938434 2016-08-08
¨ 2 ¨
[0004] A double diaphragm pump for pumping liquids, the pump comprising a
shaft assembly
mounted in a housing. The shaft assembly has a shaft with two ends and two
diaphragms,
there being one diaphragm mounted at each end of the two ends of the shaft.
Two pumping
chambers are located within the housing outside of each diaphragm and a piston
assembly
surrounds the shaft, the shaft assembly being slidable between the two pumping
chambers and
the piston assembly being slidable in the same direction as the shaft
assembly. Two rows of a
plurality of electromagnetic coils surround the shaft, the two rows being
spaced apart from one
another and being parallel to one another with each electromagnetic coil in
one row being
adjacent to an electromagnetic coil in the other row. The adjacent
electromagnetic coils in the
two rows each form a pair of electromagnetic coils; the electromagnetic coils
located within each
row being spaced-apart from one another. A plurality of sets of permanent
magnets
surrounding said shaft, each set having a plurality of permanent magnets that
are slightly
spaced apart from one another. Each permanent magnet of the plurality of
permanent magnets
of each set being arranged so that adjacent permanent magnets within each set
have opposing
polarity and the plurality of permanent magnets in alternating sets have
opposing polarity to
each adjacent set. There is one set of permanent magnets located between each
pair of
electromagnetic coils. The two rows of electromagnetic coils are fixedly
mounted on one of the
housing and the piston assembly and the plurality of sets of permanent magnets
are fixedly
mounted on another of the piston assembly and the housing respectively. A void
between the
shaft assembly and the piston assembly is filled with buffer fluid, the
electromagnetic coils being
connected to alternate polarity. The alternating polarity of the
electromagnetic coils causes the
sets to simultaneously move longitudinally relative to the electromagnetic
coils in one direction
for one stroke and in an opposite direction for one stroke, thereby causing
the piston assembly
to reciprocate within the housing between the two pumping chambers. The
reciprocating piston
assembly is located to exert pressure on the buffer fluid, which in turn
causes the shaft
assembly to reciprocate between the pumping chambers and there are
inlet/discharge ports and
check valves to facilitate pumping action.
[0005] A double diaphragm pump for pumping liquids, the pump comprising a
shaft assembly
mounted in a housing, the shaft assembly having a shaft with two ends and two
diaphragms,
there being one diaphragm mounted at each end of the two ends of the shaft.
Two pumping
chambers are located within the housing outside of each diaphragm. A piston
assembly
surrounds the shaft, the shaft assembly being slidable between the two pumping
chambers and
the piston assembly being slidable in the same direction as the shaft
assembly. A void between
the shaft assembly and the piston assembly is filled with buffer fluid. A
combination of
CA 02938434 2016-08-08
¨ 3 ¨
electromagnetic coils and permanent magnets are arranged to form a tubular
linear motor that is
connected to a power source to cause the electromagnetic coils to repeatedly
alternate polarity
to cause the piston assembly to reciprocate within the housing between the two
pumping
chambers. The reciprocating piston assembly exerts pressure on the buffer
fluid, which in turn
causes the shaft assembly to reciprocate; there are inlet/discharge ports and
check valves to
facilitate pumping action.
[0006] A double diaphragm pump for pumping liquids, the pump comprising:
(a) a shaft assembly mounted in a housing, the shaft assembly having a
shaft with two ends
and two diaphragms, there being one diaphragm mounted at each end of the two
ends of the
shaft;
(b) two pumping chambers located within the housing outside of each
diaphragm;
(c) a piston assembly surrounding the shaft, the shaft assembly being
slidable between the
two pumping chambers and the piston assembly being slidable in the same
direction as the
shaft assembly;
(d) two rows of a plurality of electromagnetic coils surrounding the shaft,
the two rows being
spaced apart from one another and being parallel to one another with each
electromagnetic coil
in one row being adjacent to an electromagnetic coil in the other row, the
adjacent
electromagnetic coils in the two rows forming a pair of electromagnetic coils;
(e) a plurality of sets of permanent magnets surrounding said shaft, each
set having a
plurality of permanent magnets that are slightly spaced apart from one
another;
(f) each permanent magnet of the plurality of permanent magnets of each set
being
arranged so that adjacent permanent magnets within each set have opposing
polarity and the
plurality of permanent magnets in alternating sets have opposing polarity to
each adjacent set,
there being one set of permanent magnets located between each pair of
electromagnetic coils;
(g) the two rows of electromagnetic coils being fixedly mounted on one of
the housing and
the piston assembly and the plurality of sets of permanent magnets being
fixedly mounted on
another of the piston assembly and the housing respectively;
(h) a void between the shaft assembly and the piston assembly being filled
with buffer fluid;
(i) the electromagnetic coils being connected to alternating polarity
voltage, the alternating
polarity voltage of the electromagnetic coils causing the sets to
simultaneously move
longitudinally relative to the electromagnetic coils in one direction for one
stroke and in an
opposite direction for one stroke, thereby causing the shaft assembly to
reciprocate;
(i) the reciprocating piston assembly being located to exert pressure on
the buffer fluid,
CA 02938434 2016-08-08
¨ 4 ¨
which in turn causes the shaft assembly to reciprocate between the pumping
chambers; and
(k) inlet/discharge ports and check valves to facilitate pumping action.
[0007] A double diaphragm pump for pumping liquids, the pump comprising:
(a) a shaft assembly mounted in a housing, the shaft assembly having a
shaft with two ends
and two diaphragms, there being one diaphragm mounted at each end of the two
ends of the
shaft;
(b) two pumping chambers located within the housing outside of each
diaphragm;
(c) a piston assembly surrounding the shaft, the shaft assembly being
slidable between the
two pumping chambers and the piston assembly being slidable in the same
direction as the
shaft assembly;
(d) two rows of a plurality of first electromagnetic coils surrounding the
shaft, the two rows
being spaced apart from one another and being parallel to one another with
each
electromagnetic coil in one row being adjacent to an electromagnetic coil in
the other row, the
adjacent electromagnetic coils in the two rows forming a pair of
electromagnetic coils;
(e) a plurality of sets of second electromagnetic coils surrounding said
shaft, each set
having a plurality of second electromagnetic coils that are slightly spaced
apart from one
another;
(f) each permanent magnet of the plurality of second electromagnetic coils
of each set
being arranged so that adjacent second electromagnetic coils within each set
have opposing
polarity and the plurality of second electromagnetic coils in alternating sets
have opposing
polarity to each adjacent set, there being one set of second electromagnetic
coils located
between each pair of first electromagnetic coils;
(g) the two rows of first electromagnetic coils being fixedly mounted on
one of the housing
and the piston assembly and the plurality of sets of second electromagnetic
coils being fixedly
mounted on another of the piston assembly and the housing respectively;
(h) a void between the shaft assembly and the piston assembly being filled
with buffer fluid;
(i) the first electromagnetic coils being connected to alternating polarity
voltage, the
alternating polarity voltage of the first electromagnetic coils causing the
sets to simultaneously
move longitudinally relative to the first electromagnetic coils in one
direction for one stroke and
in an opposite direction for one stroke, thereby causing the piston assembly
to reciprocate
within the housing between the two pumping chambers;
(i) the reciprocating piston assembly being located to exert pressure on
the buffer fluid,
which in turn causes the shaft assembly to reciprocate between the pumping
chambers; and
(k) inlet/discharge ports and check valves to facilitate pumping action.
CA 02938434 2016-08-08
¨ 5 ¨
[0008] A method of operating a double diaphragm pump for pumping liquids, the
pump having:
(a) a shaft assembly mounted in a housing, the shaft assembly having a
shaft with two ends
and two diaphragms, there being one diaphragm mounted at each end of the two
ends of the
shaft;
(b) two pumping chambers located within the housing outside of each
diaphragm;
(c) a piston assembly surrounding the shaft, the shaft assembly being
slidable between the
two pumping chambers and the piston assembly being slidable in the same
direction as the
shaft assembly;
(d) a void between the shaft assembly and the piston assembly being filled
with buffer fluid;
(e) a combination of electromagnetic coils and permanent magnets arranged
to form a
tubular linear motor that is connected to a power source to cause the
electromagnetic coils to
repeatedly alternate polarity to cause the piston assembly to reciprocate
within the housing
between the two pumping chambers;
(f) the reciprocating piston assembly exerting pressure on the buffer
fluid, which in turn
causes the shaft assembly to reciprocate;
(9) inlet/discharge ports and check valves to facilitate pumping action;
(h) the method comprising connecting the tubular linear motor to a power
source to cause
the electromagnetic coils to repeatedly alternate polarity, thereby causing
some of the
permanent magnetics to be alternately attracted and repelled by the
electromagnetic coils and
causing the piston assembly to reciprocate within the housing between the two
pumping
chambers, the piston assembly in turn causing the buffer fluid to cause the
shaft assembly to
reciprocate.
Brief Description of the Drawings
[0009] Figure 1 is a schematic cross-sectional view of a first embodiment of a
double diaphragm
pump having an electromagnetic coil affixed to a housing and permanent magnets
on either
side of the electromagnetic coil mounted to a piston assembly, with a drive
mechanism shifted
to the left;
[0010] Figure 2 is a schematic sectional view of the first embodiment of a
double diaphragm
pump as shown in Figure 1 with the drive mechanism shifted to the right;
[0011] Figure 3 is a schematic sectional side view of a second embodiment of a
double
diaphragm pump having a tubular linear motor drive, a drive portion, excluding
suction and
discharge manifolds, along the Section A-A of Figure 4;
CA 02938434 2016-08-08
¨ 6 ¨
[0012] Figure 4 is a schematic sectional view of the drive portion of the
second embodiment of
the pump; and
[0013] Figure 5 is a schematic top view of sets of a plurality of permanent
magnets located
between electromagnetic coils of a tubular linear motor drive system of the
second embodiment;
Detailed Description of the Preferred Embodiment
[0014] In Figure 1, there is shown a first embodiment of a double diaphragm
pump 2 having a
housing 4 with an electromagnetic coil 6 that is located between two permanent
magnets 8.
The electromagnetic coil 6 is preferably affixed to an interior of the housing
4 and the permanent
magnets are preferably affixed to a piston assembly 10. The piston assembly 10
is movable
relative to the housing 4. 0-rings 11 are located between the piston assembly
10 and the
housing 4 to prevent buffer fluid from contacting the electromagnetic coil 6.
[0015] A shaft assembly 12 has a shaft 14 with two ends 16,18. There are two
diaphragms
20,22, one diaphragm 20 being mounted at the end 16 of the shaft 14 and the
other diaphragm
22 being mounted at the end 18 of shaft 14.
[0016] Preferably, there is a double disk 24 mounted at the end 16 and a
double disk 26
mounted at the end 18. The two diaphragms 20,22 are held in place at the ends
16,18,
respectively, by the double discs 24,26, respectively. An outer edge 28 of
each of the
diaphragms 20,22 is affixed to the housing 4. There are two pumping chambers
30,32 that are
located immediately outside of the two diaphragms 20,22, respectively.
Diaphragm covers
34,36 of the housing 4 are located outside the pumping chambers 30,32,
respectively. The
shaft 14 is slidably mounted in a shaft support 38 which is affixed to the
housing 4. Preferably,
the shaft support 38 is a sleeve 39 that surrounds the shaft 14. A void
between the shaft
support 38, the shaft assembly 12, the diaphragms 20,22, the piston assembly
10, and that part
of the housing 4 between the diaphragms is filled with buffer fluid 40. The
pumping chambers
30,32 have four check valve assemblies with balls 42 and seats 44. The check
valves, seals
and inlets/outlets of the pumps of the present invention may vary. The piston
assemblies must
be sealed so that the buffer fluid does not contact the electromagnetic coil.
The electrical
connections for the electromagnetic coil 6 are conventional and are not shown.
The
electromagnetic coil 6 can be connected to an alternating polarity voltage to
cause the polarity
of the coil to alternate. The permanent magnets 8 have like polarity facing
the coil and are
spaced apart from one another and at least one of the permanent magnets is
always spaced
apart from the electromagnetic coil. At the end of each stroke of the pump,
one of the two
CA 02938434 2016-08-08
¨ 7 ¨
permanent magnets is in contact with the electromagnetic coil. The
electromagnet 6 and the
two permanent magnets 8 along with the piston assembly 10 preferably extend
around the
sleeve 39 of the shaft support 38.
[0017] In operation, as the polarity of the electromagnetic coil alternates,
one of the permanent
magnets is attracted to the electromagnetic coil, while the other permanent
magnet is repelled.
When the polarity of the electromagnetic coil changes, the opposite occurs
causing the piston
chamber to reciprocate between the two diaphragms. The reciprocation of the
piston assembly
in turn exerts alternating pressure on the buffer fluid, which in turn causes
the shaft assembly
and diaphragms to reciprocate, thereby alternately exerting pressure on one
pumping chamber
and then the other.
[0018] In Figure 1, the piston assembly and the shaft assembly is shown to be
closer to the
pumping chamber 30 (i.e. the left side of the drawing) and further from the
pumping chamber
32. In Figure 2, the piston assembly and the shaft assembly are shown to be
closer to the
pumping chamber 32 (i.e. the right side of the drawing) and further from the
pumping chamber
30. As the drive mechanism reciprocates, the piston assembly will move from
side-to-side from
first compressing one pumping chamber and then the other, as shown in Figures
1 and 2,
respectively. The same reference numerals are used in Figure 2 for those
components that are
identical to the components in Figure 1. The electromagnetic coils of the
first embodiment are
preferably powered by DC voltage and DC current. The polarity of the
electromagnetic coils is
reversed at the end of each stroke. The pumping chambers 30, 32 are fluidly
connected
through passage 37, which contains pump inlet 41 and passage 43, which
contains pump outlet
45.
[0019] In Figures 3 and 4, there is shown a second embodiment of the double
diaphragm pump
of the present invention. The same reference numerals are used in Figures 3
and 4 for those
components that are identical, or very similar, to the components of the
double diaphragm pump
2. A double diaphragm pump 46 has a housing 48 with a piston assembly 50
surrounding the
shaft 12.
[0020] The shaft support 38 is preferably a sleeve 39 that is anchored to the
housing 4, 48 at
one end, as shown in Figures 1, 2 and 3. The passage 37 extends through a
suction manifold
portion of the housing and the passage 43 extends through the discharge
manifold portion of
the housing. The suction manifold extends between the two check valves at a
lower end of the
housing and the discharge manifold extends between the two check valves at an
upper end of
the housing of each embodiment.
CA 02938434 2016-08-08
- 8 ¨
[0021] The piston assembly 50 has two substantially parallel rows 52,54 of a
plurality of spaced-
apart first electromagnetic coils 56,58, respectively, that are fixedly
mounted in the housing 48.
The rows 52,54 extend around the shaft 14 and the first electromagnetic coils
56, in row 52, are
immediately adjacent to and form a pair 60 with the first electromagnetic
coils 58 in row 54.
Sets 62 of a plurality of permanent magnets 64 extend around the shaft, the
sets being affixed
to the piston assembly 50. Each set 62 contains a plurality of permanent
magnets 64 and one
set 62 is located between adjacent pairs 60. The number of sets 62 is equal to
the number of
pairs 60. Each set 62 contains a plurality of permanent magnets and the
permanent magnets
within each set are oriented to have an opposite polarity to immediately
adjacent permanent
magnets within the set and are spaced slightly apart from immediately adjacent
permanent
magnets. The shaft assembly 12 is centrally located in Figure 3 with
diaphragms 20, 22 and
disks 24, 26 being equidistant from the adjacent outer wall of the housing 48.
When the pump
46 is operating, one of the pumping chambers 30 or 32 is always under
compression and the
other pumping chamber 32 or 30 respectively is always under suction, as the
piston assembly
12 is reciprocating toward one side and then other.
[0022] The electromagnetic coils 56,58 are electrically connected to
alternating polarity voltage,
thereby causing the sets 62 to simultaneously move longitudinally relative to
the
electromagnetic coils in one direction for one stroke and in an opposite
direction for another
stroke, thereby causing the piston assembly to reciprocate within the housing
between the two
pumping chambers 30,32. As with the first embodiment, the reciprocating piston
assembly 50
of the second embodiment exerts pressure on the buffer fluid 40, which in turn
causes the shaft
assembly 12 to reciprocate between the pumping chambers. There are
inlet/discharge ports
42,44, seals and check valves to facilitate pumping action. As shown in
Figures 3 and 4, the
electromagnetic coils 56,58 are arranged in two substantially parallel rows
52,54, respectively.
Both the electromagnetic coils 56,58 and the sets 62 of permanent magnets 64
extend around
the shaft 14.
[0023] In Figure 5, there is shown a schematic top view of the sets 62 of
permanent magnets
64.The curvature in the spacial relationship between the sets 62 and the
electromagnetic coils
56,58 shown in Figure 4, is not captured in Figure 5. Figure 5 is drawn as
though the sets 62
and coils 56,58 were located substantially in the same plane. The same
reference numerals are
used in Figure 5 as those used in Figures 3 and 4, to identify those
components that are
identical. The sets move longitudinally in one direction and then in the
opposite direction
relative to the magnetic coils, with each direction of movement representing
one stroke of the
pump. Preferably, the power source for the second embodiment is an AC voltage
that provides
CA 02938434 2016-08-08
¨ 9 ¨
an AC current to the electromagnetic coils 56,58 causing the sets 62 and the
piston assembly
50 to move in one direction for one stroke. When the sequence of polarity
changes at the end
of each stroke, the sets 62 and the piston assembly 50 move in an opposite
direction for one
stroke. The piston assembly 50 reciprocates, causing pressure to be placed on
the buffer fluid
40, which in turn causes the shaft assembly 12 to reciprocate.
[0024] While it is preferable to have the electromagnetic coils affixed to the
housing and the
permanent magnets affixed to the piston assembly, as a variation, the
electromagnetic coils can
be affixed to the piston assembly and the permanent magnets can be affixed to
the housing.
Further, while it is preferable to use electromagnetic coils and permanent
magnets as described
above for the first and second embodiments, as a further variation, the
permanent magnets can
be replaced by additional electromagnetic coils that are electrically
connected to function as
permanent magnets.
[0025] Preferably, the double diaphragm pumps of the present invention are
used for pumping
liquids 66. The liquids can contain some solids or particulates. The pumping
chambers of the
double diaphragm pump are preferably fluidly connected to one another.
[0026] The drive of the second embodiment is a tubular/linear motor. The
buffer fluid
hydraulically reciprocates the diaphragms in a manner that is gentler than it
would be if the shaft
and diaphragm assemblies were caused to reciprocate directly by
electromagnetic force.
[0027] The permanent magnets of each set of the second embodiment are spaced-
apart slightly
from one another.
[0028] Some of the advantages of the pumps of the present invention are as
follows. The
double diaphragm pumps can run dry, are self-priming, and can be operated with
variable flow
and with variable pressure. No seals are required except for seals to ensure
that the buffer fluid
does not enter the interior of the piston assembly. The pumps can be used to
handle viscous
liquids, liquids containing solids and/or chemicals. The pumps of the present
invention are not
dependent on compressed air, which can be very expensive. Metering can be
provided by the
use of spring check valves and the pumps can be designed for submersible use.
Pumps can
also be used for batching, pH balance or blending and can be controlled
remotely, for example,
by a Smart Phone. Also, data collection or tracking can be utilized with the
pumps for inventory
control, quality control, production reports and monitoring. The pumps can
handle many
industry-specific process functions which can be automated and monitored
remotely. For
example, the voltage level at which the pump operates, the cycle rate, or
turning the power
CA 02938434 2016-08-08
- 10 ¨
on/off can be automated and monitored remotely. The pumps can be used in waste
water
treatment involving the dosing of chemicals such as chlorine, flocculents,
acids or caustics using
pH, free chlorine or ORP controllers and/or a flow meter. The pumps are
positive displacement
in that a given volume of pumpage is discharged with each stroke or fraction
of a stroke.
Accurate control of the dispensed volume can therefore be obtained for
batching or metering.
Batching can normally be achieved with the standard ball checks and a cycle
monitor that can
be pre-set and countdown to shutoff. Metering requires a higher degree of
accuracy than
batching and can be better attained with spring-loaded poppet style or
polymeric dihedral style
valving. The linear motor design can be controlled down to 1/5 of a stroke,
since each change
in polarity moves the piston 1/5 of a full stroke. A cycle or stroke monitor
as used for batching
or a cycle rate controller which provides accurate dosing. The linear motor
design shown in
Figure 3 is particularly useful for metering because of the stroke control
capability.
[0029] The double diaphragm pumps shown in the drawings have dual manifolds.
[0030] Fasteners to fasten the components together have not been shown in the
drawings and
will be readily apparent to those skilled in the art. The components described
as the housing
will be fastened together, preferably by volting as volting enables the
components to be
separated for repair purposes. All of the seals are not shown in the drawings
and will be readily
apparent to those skilled in the art.
[0031] The positive displacement feature, with optional weighted check valves,
allows the
pumps to handle high viscosity and/or specific gravity fluids efficiently.
Changing to flap style
check valves allows the pumps to handle slurries with solids up to the size of
the inlet port. A
two phase AC voltage that is 90 out of phase can be used to provide the
alternating polarity
voltage.
[0032] The pump drive section can be bolted in place with existing
manufacturer's components.
These components can be made from a range of various metals, plastics and
elastomers.
Components to meet the FDA and/or dairy standards for the food industry are
also available.
[0033] Powdered solids can sometimes be handled with custom modifications to
the pumping
chamber and valve housings to keep the powder fluidized. Electronic and
computer processing
can also be used to provide remote control and monitoring.
[0034] Variations with the scope of the claims will be readily apparent to
those skilled in the art.
