DOUBLE ACTING FLUID ACTUATED TELESCOPIC CYLINDER

CYLINDRE TELESCOPIQUE A FLUIDE A DOUBLE ACTION

English Abstract

A double acting fluid actuated telescopic cylinder, includes an outer barrel,
and inner
barrel and a tubular member. The inner barrel is positioned within the outer
barrel. The
tubular member is positioned in an annular chamber formed between the inner
barrel and the
outer barrel. An annular piston is positioned at a second end of the tubular
member. The
annular piston has outer seals means adapted to seal against an interior
surface of the outer
barrel, while accommodating relative reciprocating movement between the
annular piston and
the outer barrel. The annular piston has inner seals adapted to seal against
the exterior surface
of the inner barrel, while accommodating relative reciprocating movement
between the
annular piston and the inner barrel. Fluid is pumped into the annular chamber
to selectively
initiate relative movement of the annular piston in a first direction or a
second direction.

French Abstract

Un vérin télescopique à double effet actionné par un liquide comprend un tube externe, un tube interne et une membrane tubulaire. Le tube interne se trouve dans le tube externe. La membrane tubulaire est placée dans une chambre annulaire entre le tube interne et le tube externe. Situé à une extrémité de la membrane tubulaire, le piston annulaire comporte des joints extérieurs adaptés de façon hermétique à la surface intérieure du tube externe, tout en assurant un mouvement de va-et-vient relatif entre le piston annulaire et le tube externe. Le piston annulaire comporte également des joints internes adaptés de façon hermétique à la surface extérieure du tube intérieur, tout en assurant un mouvement de va-et-vient relatif entre le piston annulaire et le tube interne. Le liquide est pompé dans la chambre annulaire pour activer de manière sélective le mouvement relatif du piston annulaire dans une première direction ou une deuxième direction.

Claims

7
What is Claimed is:
1. An apparatus, comprising:
an outer barrel having a first end, a second end, an exterior surface and an
interior
surface defining a primary interior bore;
a first end cap being positioned at the first end of the outer barrel, the
first end cap
having a central opening;
a second end cap being positioned at the second end of the outer barrel, the
second
end cap having a central opening;
an inner barrel having a first end, a second end, an exterior surface and an
interior
surface defining a secondary interior bore, the inner barrel being positioned
in the central
opening of the second end cap affixed to the second end cap and extending into
the primary
interior bore, such that an annular chamber is formed between the interior
surface of the outer
barrel and the exterior surface of the inner barrel;
a tubular member having a first end, a second end, an exterior surface and an
interior
surface, the tubular member being positioned in the annular chamber with the
first end of the
tubular member extending through the central opening in the first end cap;
means for forming a seal between the exterior surface of the tubular member
and the
first end cap, while accommodating relative reciprocating movement between the
tubular
member and the first end cap;
an annular piston being positioned at the second end of the tubular member,
the
annular piston having outer sealing means adapted to seal against the interior
surface of the
outer barrel, while accommodating relative reciprocating movement between the
annular
piston and the outer barrel and inner sealing means adapted to seal against
the exterior surface
of the inner barrel, while accommodating relative reciprocating movement
between the
annular piston and the inner barrel;
a first fluid port in communication with the annular chamber at the first end
of the
outer barrel, whereby fluid is pumped into the annular chamber to initiate
relative movement
of the annular piston and the outer barrel in a first direction; and
a second fluid port in communication with the annular chamber at the second
end of
the outer barrel, whereby fluid is pumped into the annular chamber to initiate
relative

8
movement of the annular piston and the outer barrel in a second direction.
2. The apparatus as defined in Claim 1, wherein the first end of the tubular
member is closed
and means are provided for forming a seal between the exterior surface of the
inner barrel and
the interior surface of the tubular member, such that the interior surface of
the tubular member
defines an extension of the secondary interior bore, a secondary fluid having
ingress and
egress to the secondary interior bore at the second end of the inner barrel
during reciprocating
movement of the tubular member with such secondary fluid being influenced by
expansion
and contraction of the secondary interior bore.
3. A method comprising the steps of
providing an apparatus, comprising:
an outer barrel having a first end, a second end, an exterior surface and an
interior surface defining a primary interior bore;
a first end cap being positioned at the first end of the outer barrel, the
first end
cap having a central opening;
a second end cap being positioned at the second end of the outer barrel, the
second end cap having a central opening;
an inner barrel having a first end, a second end, an exterior surface and an
interior surface defining a secondary interior bore, the inner barrel being
positioned in the
central opening of the second end cap affixed to the second end cap and
extending into the
primary interior bore, such that an annular chamber is formed between the
interior surface of
the outer barrel and the exterior surface of the inner barrel;
a tubular member having a first end, a second end, an exterior surface and an
interior surface, the tubular member being positioned in the annular chamber
with the first
end of the tubular member extending through the central opening in the first
end cap;
means for forming a seal between the exterior surface of the tubular member
and the first end cap, while accommodating relative reciprocating movement
between the
tubular member and the first end cap;
an annular piston being positioned at the second end of the tubular member,

9
the annular piston having outer sealing means adapted to seal against the
interior surface of
the outer barrel, while accommodating relative reciprocating movement between
the annular
piston and the outer barrel and inner sealing means adapted to seal against
the exterior surface
of the inner barrel, while accommodating relative reciprocating movement
between the
annular piston and the inner barrel;
a first fluid port in communication with the annular chamber at the first end
of
the outer barrel, whereby fluid is pumped into the annular chamber to initiate
relative
movement of the annular piston and the outer barrel in a first direction; and
a second fluid port in communication with the annular chamber at the second
end of the outer barrel, whereby fluid is pumped into the annular chamber to
initiate relative
movement of the annular piston and the outer barrel in a second direction; and
passing fluids through the secondary interior bore while alternately pumping
fluids
into the first fluid port and the second fluid port to reciprocally move the
annular piston along
the annular chamber.

Description

CA 02486507 2004-11-26
1
TITLE OF THE INVENTION:
Double Acting Fluid Actuated Telescopic Cylinder
FIELD OF THE INVENTION
The present invention relates to a fluid actuated telescopic cylinder, which
is can be
activated in two directions for use in lifting, pressing or pumping
applications.
BACKGROUND OF THE INVENTION
Double acting fluid actuated telescopic cylinders come in a variety of
configurations.
United States Patent 4,462,763 (MacLeod 1984) is an example of a double acting
fluid
actuated telescopic cylinder, which was developed for use in an oilfleld
pumping application.
SUMMARY OF THE INVENTION
According to the present invention there is provided a double acting fluid
actuated
telescopic cylinder, which includes an outer barrel, an inner barrel and a
tubular member. The
outer barrel has a first end, a second end, an exterior surface and an
interior surface defining a
primary interior bore. A first end cap is positioned at the first end of the
outer barrel. The
first end cap has a central opening. A second end cap is positioned at the
second end of the
outer barrel. The second end cap has a central opening. The inner barrel has a
first end, a
2 0 second end, an exterior surface and an interior surface defining a
secondary interior bore. The
inner barrel is positioned in the central opening of the second end cap
affixed to the second
end cap and extending into the primary interior bore. This forms an annular
chamber between
the interior surface of the outer barrel and the exterior surface of the inner
barrel. The tubular
member has a first end, a second end, an exterior surface and an interior
surface. The tubular
2 5 member is positioned in the annular chamber with the first end of the
tubular member
extending through the central opening in the first end cap. Means are provided
for forming a
seal between the exterior surface of the tubular member and the first end cap,
while
accommodating relative reciprocating movement between the tubular member and
the first
end cap. An annular piston is positioned at the second end of the tubular
member. The
3 0 annular piston has outer sealing means adapted to seal against the
interior surface of the outer
barrel, while accommodating relative reciprocating movement between the
annular piston and
the outer barrel. The annular piston also has inner sealing means adapted to
seal against the

CA 02486507 2004-11-26
2
exterior surface of the inner barrel, while accommodating relative
reciprocating movement
between the annular piston and the inner barrel. A first fluid port is in
communication with
the annular chamber at the first end of the outer barrel, whereby fluid is
pumped into the
annular chamber to initiate relative movement of the annular piston and the
outer barrel in a
first direction. A second fluid port is in communication with the annular
chamber at the
second end of the outer barrel, whereby fluid is pumped into the annular
chamber to initiate
relative movement of the annular piston and the outer barrel in a second
direction.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the
following description in which reference is made to the appended drawings, the
drawings are
for the purpose of illustration only and are not intended to in any way limit
the scope of the
invention to the particular embodiment or embodiments shown, wherein:
FIG. 1 is a perspective view, in section, of a double acting fluid actuated
telescopic
cylinder constructed in accordance with the teachings of the present
invention.
FIG. 2 is a side elevation view, in section, of the double acting fluid
actuated
telescopic cylinder illustrated in FIG.1.
2 0 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment, a double acting fluid actuated telescopic cylinder
generally identified by reference numeral 10, will now be described with
reference to
FIGURES 1 and 2.
2 5 Structure and Relationship of Parts:
Referring to FIG.1 and FIG. 2 telescopic cylinder 10 includes an outer barrel
12,
inner barrel 14 and an intermediate tubular member 16. Outer barrel 12 has a
first end 18, a
second end 20, an exterior surface 22 and an interior surface 24 defining a
primary interior
bore 26. A first end cap 28 is positioned at first end 18 of outer barrel 12.
First end cap 28
3 0 has a central opening 30. A second end cap 32 is positioned at second end
20 of outer barrel
12. Second end cap 32 has a central opening 34.
Inner barrel 14 has a first end 36, a second end 38, an exterior surface 40
and an

CA 02486507 2004-11-26
3
interior surface 42 defining a secondary interior bore 44. Inner barrel 14 is
positioned in
central opening 34 of second end cap 32 and is affixed to second end cap 32,
so there is not
relative movement between inner barrel 14 and outer barrel 12. Inner barrel 14
extends into
primary interior bore 26. The extent to which inner barrel 14 extends into
primary interior
bore 26, determines the reciprocating stroke length of tubular member 16, as
will hereinafter
be further described. It is, therefore, preferred that inner barrel 14 extend
for substantially the
entire length of primary interior bore 26. An annular chamber 46 is formed
between interior
surface 24 of outer barrel 12 and exterior surface 40 of inner barrel 14.
Tubular member 16 has a first end 48, a second end 50, an exterior surface 52
and an
interior surface 54. Tubular member 16 is positioned in annular chamber 46
with first end 48
of tubular member 16 extending through central opening 30 in first end cap 28.
A seal ring
56 is positioned in first end cap 28 encircling central opening 30, forming a
seal between
exterior surface 52 of tubular member 16 and first end cap 28, while
accommodating relative
reciprocating movement between tubular member 16 and first end cap 28. An
annular piston
58 is positioned at second end 50 of tubular member 16. Annular piston 58 has
a number of
outer sealing rings 60 (three are illustrated) adapted to seal against
interior surface 24 of outer
barrel 12, while accommodating relative reciprocating movement between annular
piston 58
and outer barrel 12. Annular piston 58 also has a number of inner sealing
rings 62 (two are
2 0 illustrated) adapted to seal against exterior surface 40 of inner barrel
14, while
accommodating relative reciprocating movement between annular piston 58 and
inner barrel
14.
A first fluid port 64 is in communication with annular chamber 46 at first end
18 of
2 5 outer barrel 12, whereby fluid is pumped into annular chamber 46 to
initiate relative
movement of annular piston 58 and outer barrel 12 in a first direction. The
term relative
movement is used, between outer barrel 12 may be fixed in position with
annular piston and
tubular member 16 being movable, or tubular member 16 may be fixed in position
with outer
barrel 12 being movable, or they could be supported so that there is some
movement of both
3 0 outer barrel 12 and tubular member 16. A second fluid port 66 is in
communication with
annular chamber 46 at second end 20 of outer barrel 12, whereby fluid is
pumped into annular
chamber 46 to initiate relative movement of annular piston 58 and outer barrel
12 in a second

CA 02486507 2004-11-26
4
direction.
Operation:
The operation of telescopic cylinder 10 will now be described with reference
to
FIGURES 1 and 2. Telescopic cylinder 10 was originally developed for use in an
oilfield
application known as "snubbing". For snubbing an upward lifting force must be
provided to
lift pipe out of an oil well and a downward pushing force must be provided to
overcome
resisting pressure and force pipe into an oil well. For this application,
outer barrel 12 is fixed
in position. In order to facilitated the fixing of outer barrel 12 at a well
installation,
attachment brackets 68 are provided on exterior surface 22 of outer barrel 12.
In such a
snubbing operation, telescopic cylinder 10 would normally be operated in pairs
straddling the
well bore, in order to provide central access to the well bore. As hydraulic
fluid is pumped
through first fluid port 64 into annular chamber 46 and is drawn from annular
chamber 46
through second fluid port 66, annular piston 58 moves along annular chamber 46
in a first
direction toward second end 20 of outer barrel 12 as indicated by first arrow
70. As hydraulic
fluid is pumped through second fluid port 66 into annular chamber 46 and is
drawn from
annular chamber 46 through first fluid port 64, annular piston 58 moves along
annular
chamber 46 in a second direction towaxd first end 18 of outer barrel 12 as
indicated by second
arrow 72. In this snubbing application, it is desirable for the upward force
to roughly equal
2 0 the downward force. When the upward force is excessive, there is a danger
of the well string
of numbers joined sections of pipe separating. For this application, a lower
face 74 of annular
piston 58 has a cut away portion 76. The purpose of cut away portion 76 is to
make the
surface area of annular piston 58 against which the hydraulic fluid acts
roughly the same. It
will be understood that the movement of annular piston 58 in second direction
72 causes
2 5 tubular member 16 to telescopically extend past first end 18 of outer
barrel 12 and movement
of annular piston 58 in first direction 70 causes tubular member 16 to
telescopically retract
back into outer barrel 12. It is this movement of tubular member 16, which
provides an
upward lifting force or a downward pushing force.
3 0 During the operation of telescopic cylinder 10, fluids, such as high
pressure gas or
liquids, may be transported through secondary interior bore 44 without
affecting the
movement and operation of telescopic cylinder 10.

CA 02486507 2004-11-26
Variations:
Refernng to FIG. 2, although telescopic cylinder 10 was originally developed
for a
lifting and pushing application, it can readily be adapted for a pumping
application. This is
5 accomplished by closing first end 48 of tubular member 16. In the
illustration first end 48 has
been closed by a plug 78, depending upon the nature of the intended
application plug can be
permanent or made removable. A sealing ring 80 is positioned on exterior
surface 40 of
inner barrel 14 at first end 36 to form a seal between exterior surface 40 of
inner barrel 14 and
interior surface 54 of tubular member 16. It will be understood that interior
surface 54 of
tubular member 16 defines an extension of secondary interior bore 44.
In a pumping application, a secondary fluid having ingress and egress to
secondary
interior bore 44 at second end 38 of inner barrel 14 during reciprocating
movement of tubular
member 16 is influenced by expansion and contraction of secondary interior
bore 44. Upon
movement of tubular piston 58 and tubular member 16 in second direction 72,
secondary
interior bore 44 expands the secondary fluid is drawn into secondary interior
bore 44. Upon
movement of tubular piston 58 and tubular member 16 in first direction 70,
secondary interior
bore 44 contracts and the secondary fluid is expelled from secondary interior
bore 44.
2 0 In a snubbing application, the secondary fluid which is drawn into
secondary interior
bore 44 upon movement in second direction 72 and is expelled from secondary
interior bore
44 upon movement in first direction 70 is air. It will be appreciated, that
this can readily be
adapted for a pumping application involving liquids.
2 5 In this patent document, the word "comprising" is used in its non-limiting
sense to
mean that items following the word are included, but items not specifically
mentioned are not
excluded. A reference to an element by the indefinite article "a" does not
exclude the
possibility that more than one of the element is present, unless the context
clearly requires that
there be one and only one of the elements.
It will be apparent to one skilled in the art that modifications may be made
to the
illustrated embodiment without departing from the spirit and scope of the
invention as

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Representative Drawing