GB2409709A - Cylinder liner retention system - Google Patents

Abstract

Apparatus and method for aligning and securing a cylinder liner 3 to a reciprocating pump. The apparatus typically comprises four arrangements 20 positioned around the liner. Each arrangement comprises a housing 7 and a clamping lug 13. The housing includes a piston 8 having a stem 11 which extends through a bore in the lug and terminates in a bolt 12. The lug is rotatable about the stem to selectively engage the cylinder liner. The piston is hydraulically operated to move away from the pumping module 2 to allow rotation of the lug to engage the liner, removal of the hydraulic pressure on the piston allows the piston to be biased towards the pumping module by elastic member 10 causing the lug to forcibly compel the cylinder liner towards the pumping module.

Description

1 240910 1 Improved Liner Retention System

_

3 This present invention relates to apparatus for aligning 4 and securing cylinder liners to pumps and in particular, though not exclusively, to apparatus for aligning and 6 securing cylinder liners of reciprocating pumps to their 7 respective pumping modules. . . 8.... :.

9 In the past, there have been several different types of ways to attach cylinder liners to their respective..

11 pumping modules and these may vary according to make of. .

12 pump in which they are used. One embodiment presently....

13 known employs a tapered concentric clamp, while another.

14 uses a concentric screw clamping arrangement. .

16 It is important that the means for aligning and securing 17 the cylinder liners may be implemented without undue 18 effort and down-time. Cylinder liners are required to be 19 changed frequently and this causes considerable inconvenience if the means and method for releasing the 21 old cylinder liners and fitting the replacement cylinder 22 liners are slow or difficult to operate. It has been 23 found that original pump manufacturers' systems or means 1 for securing cylinder liners to respective pumping 2 modules have been difficult to operate for a plurality of 3 reasons, including the involvement of heavy components, 4 the handling of which may be dangerous for operators.

These systems also require considerable strength, skill 6 and reliability of operators, together with the use of 7 heavy tools in confined spaces. Yet further, the securing 8 force is dependent on the extent of wear and the general 9 condition of a plurality of the securing components.

11 US RE37,483 has overcome some of these problems in 12 providing an apparatus for securing a cylinder liner to a 13 pumping module in a reciprocating pump which has a set of 14 arrangements each with a hydraulically activated piston, a rod attached to the piston which is adapted to receive 16 a nut, the retraction of which forcibly compels in 17 attraction against a spring, the cylinder liner and the. . . 18 pumping module. In particular, this apparatus provides a...

19 tool which can be operated by hand. A further advantage is that the tool uses components which are considerably:.

21 lighter than those of the prior art to ease handling. ...

23 However, disadvantages are found in this design as the . :.

24 operator must first assemble the apparatus, excepting the .

nuts and clamping ring. They must then lift and position 26 this on the pumping module. Although the individual 27 components of the apparatus may be comparatively light, 28 the combined weight of the assembled apparatus makes it 29 difficult to handle. Additionally the operator must lift the clamping ring into position also. This places an 31 additional weight lifting requirement on the operator.

1 Further, if any part of the assembly becomes damaged. The 2 entire apparatus must be temporarily replaced until a 3 skilled repair can be undertaken. For example, damage 4 can easily occur on the exposed threaded ends of the rods during liner changes. Yet further, the requirement to 6 have loose nuts which are threaded on the rods after 7 insertion through the clamping ring offer the risk of 8 being lost or misplaced.

It is an object of at least one embodiment of the present 11 invention to provide a liner retention tool which is 12 modular in construction so the tool is easily assembled 13 in-situ and parts can be replaced if damage occurs.

It is a further object of at least one embodiment of the 16 present invention to provide a liner retention tool which 17 does not require a clamping ring nor any loose nuts. A. - ..

19 According to a first aspect of the present invention, there is provided apparatus for securing a cylinder liner . - .

21 to a pumping module, the apparatus comprising one or more: . 22 arrangements, each arrangement comprising a housing....

23 including a piston, the piston having a stem extending.

24 therefrom through the housing at an end distal to the pumping module, a clamping lug, the stem extending 26 through a bore in the lug and terminating in a bolt, 27 wherein the lug is rotatable about the stem to 28 selectively engage the cylinder liner and wherein 29 retraction of said piston and bolt, when the lug is engaged to the liner, cause the lug to forcibly compel 31 the cylinder liner towards the pumping module.

1 By having a clamping lug associated with each 2 arrangement, the arrangements are interchangeable and 3 thus any number can be used and easily replaced if 4 damaged. Further each arrangement can be assembled separately on the liner to reduce the weight carried by 6 an operator. Yet further by incorporating a bolt with 7 each lug, there are no detachable components and thus no 8 loose parts, such as nuts, are required.

Preferably each arrangement includes a support member.

11 The support member may be located between a base of the 12 housing and the lug, lying parallel to the liner. The 13 support member removes the bending moment out of the 14 stem. Such bending could cause the lug to break across its narrowest portion if not supported. Further each 16 bore is preferably tapered. By tapering the bore, the 17 lug can pivot about the stem which, in combination with.. .

18 the support member, allows the arrangement to be self..

19 aligning and thereby remove stress on the stem and lug. 20:.

21 Preferably each arrangement includes a locking mechanism, . .

22 the locking mechanism comprising a part circular groove...

23 and a pin for locating in the groove. The groove may be 24 located around the stem and adjacent the cylinder and the .

pin may be located on the lug. Thus movement of the lug 26 in relation to the cylinder is controlled. Advantageously 27 the groove has a first and a second end, wherein when the 28 pin is located at the first end the lug engages the 29 cylinder and when the pin is located at the second end the lug is disengaged from the cylinder.

32 Preferably the one or more arrangements are fastened to a 33 base plate. More preferably the base plate is fastened to 1 said pumping module.

3 Preferably each arrangement includes at least one spring 4 located in the cylinder to act upon the piston.

6 Preferably the piston and the cylinder base define a 7 space for accommodating hydraulic fluid.

9 Preferably said one or more arrangements comprise at least four arrangements spaced at intervals about and 11 externally of the circumference of the cylinder liner.

12 Optionally a stiffening ring may be located around the 13 apparatus, parallel to the cylinder liner.

According to a second aspect of the present invention 16 there is provided a method of securing a cylinder liner 17 to a pumping module of a pump, the method comprising the. . . 18 steps: .... :.

(a) locating apparatus according to the first aspect. ..

21 onto the pumping module, around a cylinder liner; : . 22 (b) applying pressure to the piston to move it away from....

23 the pumping module; . 24 (c) rotating each clamping lug around the stem to locate .

over the cylinder liner; 26 (d) at full compression, tightening the bolt against 27 the stem; and 28 (e) releasing the pressure on the piston and forcibly 29 compelling the cylinder liner to the pumping module.

31 Step (c) may include the step of rotating a pin of the 32 lug from a first unlocked position to a second, locked, 33 position to engage the cylinder liner. (

2 Step (d) may include the step of supporting the lug on 3 tightening, while allowing the lug to pivot about the 4 stem.

6 The method may include the step of pumping hydraulic 7 fluid to the piston to apply pressure to the piston.

9 Step (e) may include the feature of a spring force to forcibly compel the cylinder liner to the pumping module.

12 The method may further include the step of applying a 13 stiffening ring around the apparatus to secure the 14 arrangements in place.

16 Example embodiments of the invention will now be 17 described by way example only, with reference to the. . 18 accompanying Figures, in which: .... :.

Figure 1 is a cross-sectional view of an arrangement of I. 21 an apparatus according to a first embodiment of the. .

22 present invention mounted on a pumping module with a...

23 cylinder liner; 24.. :.

Figure 2 is an end view of the apparatus of Figure 1; 27 Figure 3 is a cross-sectional view through a locking ring 28 of the arrangement of Figure 1; Figures 4(a)-(d) are cross-sectional views of an 31 arrangement of an apparatus illustrating various 32 embodiments which include a stiffening ring; and 1 Figure 5 is a cross-sectional view of an arrangement of 2 an apparatus according to a further embodiment of the 3 present invention.

A reciprocating pump generally described at 1 comprises a 6 module 2 and cylinder liner 3. It is desirable that the 7 cylinder liner 3 is securely held up against the face 4 8 of the module 2. Between the cylinder liner 3 and the 9 module 2 there is-provided a seal 5 which, in its unenergized (i.e., uncompressed) state, must be 11 compressed by the cylinder liner 3 to close a gap created 12 between the adjacent faces of the module 2 and cylinder 13 liner 3.

In order to prevent the existence of this gap, it is 16 necessary to forcibly push the cylinder liner 3 against 17 the module 2 and this is achieved by securing means, . . 18 generally described at 6. The effect of compressing the.

ma.. . 19 cylinder liner 3 against the face 4 of the module 2 is to energise or compress the seal 5. This compression is of.... :.

21 course desirable to increase the effectiveness and A. . 22 efficiency of the seal 5. The securing means 6 comprises 23 one or more assemblies or arrangements 20. Only one 24 arrangement 20 is shown in Figure 1, although it will be . . understood that more than one arrangement 20 may be 26 located around the cylinder 3. Each assembly comprises a 27 housing 7 which houses a piston 8 which is hydraulically 28 operated by the insertion of hydraulic fluid into a space 29 23 between the base of the piston and the rear face of the housing. In this way piston 8 may travel away from 31 the pumping module 2.

1 Extending from the piston 8 is a piston stem 11. The stem 2 11 extends from the housing 7. Located around the stem 3 11, within the housing 7 is an elastic member 10. The 4 elastic member 10 may comprise one or more metal springs arranged in parallel to the stem to act against a face of 6 the piston 8. The elastomeric member 10 may have a 7 cylindrical body and a bore passing therethrough and be 8 made up of layers of a flexible material e.g. rubber and 9 a strengthening material e.g. metal arranged perpendicular to the bore.

12 Located at the end of the housing 7, to seal the housing, 13 is a cylinder cap 9. Cap 9 is screwed onto the housing 7 14 to provide a fixed distance over which the elastic member 10 may be compressed. Cap 9 includes a bore through which 16 the stem 11 passes. Arranged between an inner surface of 17 the cap 9 and the stem 11 is a locking ring 14. Ring 14.

. 18 includes a groove 15, facing away from the pumping module.

- - .. . 19 2. A grease nipple 16 is provided through the cap 9 to the ring 14. I. . 21.'. . 22 On exiting the housing 7 the stem 11 passes through a .. . 23 clamping lug 13. There is a separate lug 13 associated . -

24 with each housing 7. Lug 13 is rotatable about stem 11. . A shoulder 19 is provided on the lug which can contact 26 the liner 3 when the lug 13 is rotated. Rotation of the 27 lug 13 about the stem 11 is controlled from a dowel or 28 pin 17. Pin 17 is located in the lug 13 at a fixed 29 position. The other end of the pin 17 locates in the groove 15 on the ring 14. Movement of the lug 13 is thus 31 dependent on the size of the groove 15 around the ring 32 14.

1 The end of the stem 11 includes an internal threaded 2 bore. A bolt 12 is threaded within this bore. Bolt 12 3 faces the pumping module 2 and its head abuts the 4 clamping lug 13. Stem 11 never extends beyond the clamping lug 13. Bolt 12 is a high strength bolt 6 providing a friction grip. Preferably the bolt is of a 7 size around M30.

9 In the embodiment shown, the securing means 6 includes one or more of arrangements 20 having the aforementioned 11 components 7 through 17. Reference is now made to Figure 12 2 of the drawings which illustrates an end view of the 13 securing means 6, facing the module 2. Four arrangements 14 2Oa-d are shown equidistantly spaced around the cylinder liner 3. Each arrangement 20a-d is connected to a base 16 plate 18. Base plate 18 is in turn bolted to the module 17 2. Although the base plate 18 is illustrated as being 18 square in shape, it will be understood that any.

19 convenient shape of base plate may be used. i.:.

21 In use, arrangements 20 are placed on the base plate 18, . . . 22 if desired. Base plate 18 is then mounted on the pumping 23 module 2. With the lugs 13 rotated clear of the liner . 24 position, the liner 3 is located on the seal 5. Referring to Figure 3, the rotational position which the lug 13 can 26 adopt is controlled from the ring 14. Groove 15 in ring 27 14 is part circular. This provides two end stops at faces 28 21,22 respectively. Rotating the lug 13 around the stem 29 11 in a first direction will cause the pin 17 to abut a first face 21. This can cause the shoulder 19 to move 31 away from the cylinder 3 and may be referred to as the 32 'open' position. When the lug 13 is rotated in the 33 opposite direction, the pin 17 will meet the second face 1 22. At this position the shoulder 19 is ideally located 2 over the cylinder 3. This may be referred to as the 3 'closed' or 'locked' position.

Hydraulic fluid is then fed to space 23. This applies a 6 pressure to the piston 8 and forces the piston away from 7 the module 2. As it is forced away the elastic member 10 8 will be compressed, the stem 11 will extend from the 9 housing 7 via the cap 9 and the bolt 12 will become slack against the screw thread in the stem 11. In this position 11 each lug 13 is rotated into the closed position with the 12 shoulder 19 located over the cylinder 3. The bolts 12 can 13 then be tightened by hand. The hydraulic fluid is then 14 released from the space 23 so that the piston 8 retracts towards the module 2 and the elastomeric member 10 16 expands. The cylinder 3 is then secured against the 17 module 2. ë e.: 18. . - - - 19 Reference is now made to Figures 4(a)-(d) which illustrate a further feature of more embodiments of the ë..

21 apparatus of the present invention. Like parts to those. . . 22 of Figure 1 have been given the same reference numeral to 23 aid clarity. Each of these figures illustrates a - 24 stiffening ring, generally indicated by reference numeral .

25. Stiffening ring 25 is located around the cylinder 26 liner 3, in contact with the apparatus 6. While the ring 27 is only shown in cross-section at a single arrangement 28 20, it will be appreciated that the ring 25 extends 29 circumferentially around the liner 3 and is in contact with all arrangements 20. Each figure, 4(a)-(d) 31 illustrates a possible location for the ring 25, though 32 it will be understood that other positions may be 33 selected. Ring 25 is designed to provide a radial 1 compression force against the liner 3 via the arrangement 2 20.

4 In Figure 4(a) the ring 25a is a band located on an inner surface of the housing 7, toward the cap 9. Any suitable 6 attachment means may be used to hold the ring 25a to the 7 housing 7. Alternatively the ring 25b can be arranged 8 around the lug 13, as illustrated in Figure 4(b). In this 9 arrangement it is optional to us an affixing means between he ring 25b and the lug 13. The converse 11 arrangement to Figure 4(a) is shown in Figure 4(c). In 12 Figure 49c) the ring 25c is located at the housing 7, but 13 is now on the outer surface. This configuration requires 14 no affixing means between the ring 25c and the housing 7.

Finally, Figure 4(d) provides an alternative ring 25d 16 design. The band of ring 25d is thinner than those 17 illustrated in the earlier Figures. This ring 25d has a. . 18 plurality of apertures 26 through which the lugs 13, as....

19 illustrated, or the cap 9 or housing 7 may be located.

This design may assist in positioning the arrangements 20 .

21 if the base plate 18 is first mounted to the module 2. .

22 before the arrangements are attached. ... 23 A :--.

24 Reference is now made to Figure 5 of the drawings which .

illustrates an arrangement, generally indicated by 26 reference numeral 120, as found in apparatus 101, 27 according to a further embodiment of the present 28 invention. Like parts to those of Figure 1 have been 29 given the same reference numeral with the addition of 100.

32 Apparatus 101 operates in an identical manner to 33 apparatus 1 except for the additional support given to 1 the lug 113 by virtue of the support 130. Support 130 is 2 a rod or other member which rests between the base 131 of 3 the housing 107 and a surface 132 of the lug 113. Lug 4 113 now incorporates downwardly extending portions 133a,b. This change in shape provides an angled lip 137 6 to the lug 113, adjacent to the cylinder cap 109. The lip 7 137 in combination with the tapered bore 135 in the lug 8 113, allows the lug to pivot about the stem 111. In this 9 way the stem 111 and lug 113 are self aligning to prevent unwanted bending stress being applied to the stem 111 11 and/or lug 113 when tension is applied. A spherical 12 washer 140 is also incorporated between the bolt 112 and 13 the lug 113 to allow for the self aligning feature.

14 Further a grease nipple 142 is incorporated to ensure the lug 113 can rotate and pivot easily about the stem 111.

16 While this embodiment will require a greater hydraulic 17 pressure to operate than the apparatus 1 described 18 earlier, the additional features remove the bending.

19 moment out of the stem 111, providing a stronger arrangement. I. 21 I. . 22 The principal advantage of the present invention is that 23 by having a separate clamping lug associated with each .

24 arrangement, the apparatus becomes modular making it .

easier to assemble, easier to replace worn or broken 26 parts and reduces the weight of the apparatus.

28 A range of these and other advantages are realised in the 29 embodiments of the present invention as: 31 1) Modular design allows almost 50% weight saving as 32 compared with present liner retention systems. This is 33 very important on land-rigs because of lack of 1 availability of lifting devices and for on offshore 2 rigs because of a requirement to minimise "deck 3 weight".

2) Modular design allows easy manual lifting into place of 6 use when required without risking back injuries, etc. 8 3) Modular design allows quick and easy replacement of 9 individual liner-clamping arrangements in event of accidental damage, etc. 12 4) No heavy clamping ring is required to be lifted in and 13 out for liner changes, providing less risk to 14 operators.

16 5) Because "open" and "closed positions of the liner 17 clamps are pre-set and there is no requirement for a.

18 clamping ring, clamping and unclamping operations are :--- 19 extremely quick.

20.....

21 6) There are no loose nuts to be located and fitted when.. . 22 performing the clamping operation after a liner change.

24 7) There are no exposed threads on studs to be damaged .

during liner changes.

27 8) There is a pumped grease sealing system on piston stem 28 at the grease nipple to ensure a good water / dirt seal 29 This avoids the use of O-rings which tend to jam, wear flat or tear.

32 Further modifications and improvements may be 33 incorporated without departing from the spirit or scope 1 of the invention. For example, though the invention has 2 particular relevance to reciprocating pumps such as oil 3 field mud pumps, the invention is not, however, limited 4 to mud pumps but finds application in a variety of reciprocating or positive displacement pumps. Further the 6 arrangements can be made more modular as the cylinder 7 base may be unscrewed from the housing, the cap may be 8 unscrewed from the housing and the piston can be removed 9 from the housing. ..e -a-:. . :. . . e ... A.. A.. - 's

Claims (1)

1 CLAIMS 3 1. Apparatus for securing a cylinder liner to a pumping 4

module, the apparatus comprising one or more arrangements, each arrangement comprising a housing 6 including a piston, the piston having a stem 7 extending therefrom through the housing at an end 8 distal to the pumping module, a clamping lug, the 9 stem extending through a bore in the lug and terminating in a bolt, wherein the lug is rotatable 11 about the stem to selectively engage the cylinder 12 liner and wherein retraction of said piston and bolt, 13 when the lug is engaged to the liner, cause the lug 14 to forcibly compel the cylinder liner towards the pumping module.

17 2. Apparatus as claimed in Claim 1 wherein each.

18 arrangement includes a support member, located 19 between a base of the housing and the lug, lying parallel to the liner. :.

21,.. . 22 3. Apparatus as claimed in Claim 1 or Claim 2 wherein 23 each bore is tapered so the lug can pivot with.

24 respect to the stem. .. :.

26 4. Apparatus as claimed in any preceding Claim wherein 27 each arrangement includes a locking mechanism, the 28 locking mechanism comprising a part circular groove 29 and a pin for locating in the groove.

31 5. Apparatus as claimed in Claim 4 wherein the groove 32 has a first and a second end, wherein when the pin is 33 located at the first end the lug engages the cylinder 1 and when the pin is located at the second end the lug 2 is disengaged from the cylinder.

4 6. Apparatus as claimed in any preceding Claim wherein the one or more arrangements are fastened to a base 6 plate adapted for fastening to said pumping module.

8 7. Apparatus as claimed in any preceding Claim wherein 9 each arrangement includes at least one spring located in the cylinder to act upon the piston.

12 8. Apparatus as claimed in any preceding Claim wherein 13 the piston and a base of the cylinder define a space 14 for accommodating hydraulic fluid.

16 9. Apparatus as claimed in any preceding Claim wherein 17 said one or more arrangements comprise at least four 18 arrangements spaced at intervals about and externally. ; 19 of the circumference of the cylinder liner. I.'.

21 10. Apparatus as claimed in any preceding Claim wherein a, '.

22 stiffening ring is located around the apparatus, 23 parallel to the cylinder liner. . : '. 24.

11. A method of securing a cylinder liner to a pumping 26 module of a pump, the method comprising the steps: 28 (a) locating apparatus according to any one of Claims 29 1 to 10 onto the pumping module, around a cylinder liner; 31 (b) applying pressure to the piston to move it away 32 from the pumping module; 1 (c) rotating each clamping lug around the stem to 2 locate over the cylinder liner; 3 (d) at full compression, tightening the bolt against 4 the stem; and (e) releasing the pressure on the piston and forcibly 6 compelling the cylinder liner to the pumping 7 module.

9 12. A method as claimed in Claim 11 wherein step (c) includes the step of rotating a pin of the lug from a 11 first unlocked position to a second, locked, position 12 to engage the cylinder liner.

14 13. A method as claimed in Claim 11 or Claim 12 wherein step (d) includes the step of supporting the lug on 16 tightening, while allowing the lug to pivot about the 17 stem. . . 18 e eeee 19 14. A method as claimed in any one of Claims 11 to 13 wherein the method includes the step of pumping * 21 hydraulic fluid to the piston to apply pressure to. . . 22 the piston. . ee.

23 . :e'.

24 15. A method as claimed in any one of Claims 11 to 14 .

wherein step (e) includes the feature of a spring 26 force to forcibly compel the cylinder liner to the 27 pumping module.

29 16. A method as claimed in any one of Claims 11 to 15 wherein the method further includes the step of 31 applying a stiffening ring around the apparatus to 32 secure the arrangements in place.