WO2013143108A1

WO2013143108A1 - Assembly for mounting cylinder liners in drilling pump

Info

Publication number: WO2013143108A1
Application number: PCT/CN2012/073278
Authority: WO
Inventors: Shunjun HUANG
Original assignee: Sichuan Honghua Petroleum Equipment Co., Ltd.
Priority date: 2012-03-30
Filing date: 2012-03-30
Publication date: 2013-10-03
Also published as: CN103946550B; CN103946550A

Abstract

An assembly for mounting cylinder liners is provided, the assembly comprising a mounting structure comprising a base plate defining a hole and an internally threaded locating collar extending from the base plate around the hole, the base plate providing flange portions on opposite sides of the collar by which the mounting structure can be secured to a cylinder block; and a locating ring configured to be located around a cylinder liner and having an externally threaded end portion, whereby when the locating ring is positioned around an end portion of a cylinder liner and engaged with the threaded locating collar, the cylinder liner is secured to the mounting structure.

Description

AN ASSEMBLY FOR MOUNTING CYLINDER LINERS IN A DRILLING PUMP

Technical Field

The disclosure relates to thefieldofoil and gasdrilling equipment. In particular, it discloses an assembly for mounting cylinder liners in a drilling pump.

Background

The developmentofoil and gas exploration has resulted in deeper drilling depths. This requires a corresponding increase in performance from the drilling pump, which is typically the centerpiece of a rig equipment. For example, drilling pumps are expected to have greater drilling power, less weight, and longer operational lifespans.

Drilling power is related to the theoretical volume displacement of a drilling pump, which is dependent on the size of the piston, the cross-section area of the cylinder liner, number of pistons and cylinder liners, average reciprocating speed of the piston, etc.Greater drilling power can be achieved using different combinations of the above factors to displace a larger volume of drilling fluid per stroke.

Drilling fluid is also known as 'mud,' and is commonly used as the working medium in a drilling pump to bring excavated rocks and soil to the ground surface. Higher reciprocating speeds of the piston can result in a larger displacement of drilling fluid over a same time interval. However, the reciprocating speed of the piston has a direct impact on the operational lifespan of the drilling pump. For example, when the pistons operate at high reciprocating speeds, the drilling fluid can have an abrasive effect on moving parts of the drilling pump, and result in quicker wear and tear of the moving parts.

In order to fulfill volume displacement requirements, alternatives to increasing the reciprocating speed of the pistons include increasing the size of the piston, the cross-section area of the cylinder liner, or the number of pistons and cylinders. Larger pistons have larger diameter piston rods, which require larger diameter cylinder liners to hold the piston rods. Conventionally, using larger pistons results in larger and heavier drilling pumps because adjacent pistons and cylinder liners have to be spaced farther apart. The increase in the center-to-center spacing between cylinders can also lead to a greater load on the crankshaft and crankcase as a result of a larger moment arm. This requires the strength of the crankshaft and crankcase to increase in order to bear the greater load during operation of the drilling pump. The strength of the crankshaft and crankcase can be increased by either reinforcing its stiffness with more material, or by changing to a material with higher yield strength. Thus, an increase in center-to-center spacing between cylinders can culminate in numerous design and material changes in the drilling pump, which increase cost.

In a previous mounting assembly, a cylindrical mounting structure serves to mount the cylinder liner and provide connection to the cylinder block, comprising a peripheral circular array of holes, through which connectors such as bolts and screws are used to secure the structure onto the cylinder block. As a result, the center-to-center spacing between cylinders is constrained by the size of the cylinder liner and the cylindrical mounting structure with peripheral circular array of holes for mounting to the cylinder block.

Summary of the Invention

One aspect of the invention comprises an assembly for mounting cylinder liners, comprising a mounting structure comprising a base plate defining a hole and an internally threaded locating collar extending from the base plate around the hole, the base plate providing flange portions on opposite sides of the collar by which the mounting structure can be secured to a cylinder block; and a locating ring configured to be located around a cylinder liner and having an externally threaded end portion , whereby when the locating ring is positioned around an end portion of a cylinder liner and engaged with the threaded locating collar, the cylinder liner is secured to the mounting structure.

Another aspect of the invention comprises a pump, comprising a cylinder liner; a piston located within the cylinder liner; a piston rod connected to the piston and projecting from an open end of the cylinder liner; and an assembly for mounting cylinder liners, comprising: a mounting structure comprising a base plate defining a hole and an internally threaded locating collar extending from the base plate around the hole, the base plate providing flange portions on opposite sides of the collar by which the mounting structure can be secured to a cylinder block; and a locating ring configured to be located around the cylinder liner and having an externally threaded end portion , whereby when the locating ring is positioned around an end portion of a cylinder liner and engaged with the threaded locating collar, the cylinder liner is secured to the mounting structure.

A discharge hole can be located in a rim of the threaded locating collar, the discharge hole extending in an axial direction from a surface of the rim of the threaded locating collar to a surface of the base plate.

In one embodiment, the mounting plate has a width substantially similar to an external diameter of the locating collar.

One embodiment of the invention provides a method of mounting a cylinder liner in an opening formed in cylinder block . The method comprises installing a gasket around the opening in the cylinder block; locating an end portion of the cylinder liner in an internally threaded locating collar of a mounting structure; positioning a locating ring around another end portion of the cylinder liner; engaging an externally threaded end portion of the locating ring with the internally threaded locating collar of the mounting structure so as to secure the cylinder liner to the mounting structure; positioning the mounting structure having the cylinder liner secured thereto over the gasket installed around the opening in the cylinder block; and securing the mounting structure to the cylinder block by means of flange portions located on the mounting structure.

The assembly allows an existing pump configuration with fixed crankshaft and cylinder block dimensions to be upgraded to have larger pistons for displacing a greater volume per stroke, without increasing the center-to-center spacing between cylinders in the drilling pump.

In this disclosure, the functions of securing the cylinder liner and connecting to the cylinder block are decoupled into different parts of a mounting structure. Flange extensions are provided on a base plate of the mounting structure for connection to the cylinder block, while a locating collar extending off the base plate holds the cylinder liner. This reduces the space required between the cylinders and allows larger diameter cylinder liner to be used without increasing the center-to-center cylinder spacing. The larger diameter cylinder liner can further accommodate a larger piston rod, which increases the volume displacement per stroke of the drilling pump.

Further aspects will be apparent from the description.

Description of the Drawings

Fig. 1 shows a section of a drilling pump comprising a cylinder block and a plurality of cylinder liners mounted onto the cylinder block according to one embodiment of the assembly.

Fig. 2 illustrates an exploded view of the components in a subsection of the drilling pump of Fig. 1.

Figs. 3A-D show different views of the mounting structure according to one embodiment.

Figs. 4A and 4B show different views comparing exemplary embodiments of the assembly with a prior art pump.

Detailed Description

The aforementioned and other aspects, solutions, and advantages of the present invention will become apparent from the following descriptions and corresponding drawings. The embodiments further clarify the present invention and shall not be construed to limit the scope of the present invention.

Fig. 1 shows a section of a drilling pump comprising a cylinder block and a plurality of cylinder liners mounted onto the cylinder block according to one embodiment of the assembly. Fig. 1 also shows cross-section views A-A and B-B of a subsection of the drilling pump comprising a cylinder liner mounted onto the cylinder block.

Fig. 2 illustrates an exploded view of the components in the subsection of the drilling pump of Fig. 1. As shown in Fig. 2, the components include a locating ring 17, a cylinder liner 19, an anti-abrasion gasket 22, a cylinder block 14, and a mounting structure 1 for mounting the cylinder liner 19 and the anti-abrasion gasket 22 onto the cylinder block 14. The mounting structure 1 comprises a base plate 2. The base plate 2 comprises

flange portions

3 and 4 by which the mounting structure 1 can be mounted onto a face portion 16 of the cylinder block 14. The

flange portions

3 and 4 of the mounting structure 1 include a plurality of holes 5 that can be aligned with a corresponding set of holes 15 on the face portion 16 of the cylinder block 14 such that the mounting structure 1 can be mounted on the cylinder block using connectors such as bolts, screws, etc. The mounting structure 1 further comprises an internally threaded locating collar 8. The locating ring 17 comprises an externally threaded portion 18, and the locating ring 17 is configured to be located around the cylinder liner 19. When the externally threaded portion 18 of the locating ring 17 is positioned around an end portion 20 of the cylinder liner 19 and engaged with the internally threaded locating collar 8 of the mounting structure 1, the cylinder liner 19 is secured to the mounting structure 1.

In one embodiment of the invention, the cylinder liner 19 can be mounted. First, the anti-abrasion gasket 22 is positioned onto the face portion 16 around an opening of the cylinder block 14 and attached onto the cylinder block 14. The anti-abrasion gasket 22 includes a plurality of holes 23 that can be aligned with a corresponding set of holes 24 on the face portion 16 of the cylinder block 14 such that the anti-abrasion gasket 22 can be attached onto the cylinder block 14 using connectors such as screws. Second, an end portion 21 of the cylinder liner 19 is located within the internally threaded locating collar 8, and the locating ring 17 is positioned around an end portion 20 of the cylinder liner 19. Third, the externally threaded portion 18 of the locating ring 17 is engaged with the internally threaded collar 8 so as to secure the cylinder liner 19 to the mounting structure 1. Lastly, the mounting structure 1 having the cylinder liner 19 secured thereto is positioned on the anti-abrasion gasket 22 installed around the opening in the cylinder block 14, and secured to the cylinder block 14 by means of the

flange portions

3 and 4, through the plurality of holes 5 on the

flange portions

3 and 4 using connectors such as bolts or screws.

Figs. 3A-D show different views of the mounting structure according to one embodiment. Fig. 3A is another 3-dimensional view of the mounting structure 1 of Fig. 2. Fig. 3B shows a view of a side of the mounting structure 1 that contacts a face portion 16 of the cylinder block 14 when mounted onto the cylinder block 14. Figs. 3C and 3D further show views of the cross-sections G-G and H-H of Fig. 3B.

In the embodiment of Fig. 3B, the mounting structure 1 comprises a base plate 2 having a substantially circular hole 7 located substantially at the center of the base plate 2. The base plate 2 comprises

flange portions

3 and 4 located on opposite sides of the circular hole 7.

The base plate 2 further comprises a plurality of holes 5 located on

flange portions

3 and 4 of the base plate 2. The plurality of holes 5 are aligned to a corresponding set of holes 15 located on the face portion 16 of the cylinder block 14. The mounting structure 1 is mounted on the cylinder block 14 using connectors such as bolts, screws, etc. located through the holes 5 on the

flange portions

3 and 4, and the holes 15 on the face portion 16 of the cylinder block 14. When the mounting structure 1 is attached on the cylinder block 14, a face portion 6 of the base plate 2 contacts the face portion 16 of the cylinder block 14 on which the mounting structure 1 is mounted.

Fig. 3B also shows a discharge hole 12 adjoining a slight recess 13 on the face portion 6 of the base plate 2. The discharge hole 12 and the slight recess 13 allow materials to be discharged from the interior of the mounting structure 1 during operation of the drilling pump.

Fig. 3C shows a view of the cross-section G-G in Fig. 3B. As shown in Fig. 3C, the mounting structure 1 comprises a locating collar 8 extending from the base plate 2 around the hole 7. The locating collar 8 is internally threaded to provide an annular threaded portion 9 in the hole 7. There is also an unthreaded hole portion 10 between the hole 7 and the annular threaded portion 9. In the embodiment shown in Fig. 3C, a diameter of the unthreaded hole portion 10 is greater than a diameter of the hole 7. In this embodiment, the centers of the locating collar 8, hole 7, annular threaded portion 9, and unthreaded hole portion 10 may lie along a common axis.

The annular threaded portion 9 and unthreaded hole portion 10 allow the locating collar 8 to be engaged with the externally threaded portion 18 of the locating ring 17 around the end portion 20 of the cylinder liner 19, shown in Fig. 2.

As shown in Fig. 3C, the base plate 2 provides

flange portions

3 and 4 on opposite sides of the locating collar 8 by which the mounting structure 1 can be attached to the cylinder block 14 of Fig. 2. The

flange portions

3 and 4 comprise a plurality of holes 5 for attaching the mounting structure 1 via a corresponding set of holes 15 located on the face portion 16 of the cylinder block 14 shown in Fig. 2, using connectors such as bolts, screws, etc.

The plurality of holes 5, together with a plurality of holes 25 on the

flange portions

3 and 4, may be used as tooling holes during the fabrication of the mounting structure 1. For instance, the mounting structure 1 may be machined from a workpiece. The workpiece can be mounted onto spacer blocks using the plurality of holes on the flange portions, instead of being held in place using a fixturing clamp. Avoiding the use of a fixturing clamp during machining can help prevent part deformation, and improve machining tolerances of the workpiece relating to flatness, parallelism, etc. For example, a cylindricity of the hole 7 is approximately 0.01mm; a concentricity between the hole 7 and an external surface of the locating collar 8 is approximately 0.03mm; a gap between an inner surface of the hole 7 and an outer surface of the cylinder liner 19 located within the hole 7 is approximately 0.02-0.08mm; a flatness of the face of the base plate 2 in contact with the face of the cylinder block 14 is approximately 0.015mm; a flatness of the face of the base plate 2 located on the side of the locating collar 8 is approximately 0.015mm; a parallelism between opposite faces of the base plate 2 is approximately 0.02mm; a thickness tolerance of the base plate 2 is approximately 0.03mm; a concentricity between the hole 7 and an external surface of the locating collar 8 is approximately 0.04mm; a cylindricity of an outer surface of the locating collar 8 is approximately 0.01mm; and a perpendicularity offset between an axis of the outer surface of the locating collar 8 and a face of the base plate 2 is approximately 0.03mm.

Fig. 3D shows a view of the cross-section H-H in Fig. 3B. As illustrated in Figs. 3B and 3D, the mounting structure 1 comprises a discharge hole 12 extending in an axial direction from the rim of the locating collar 8 to the face portion 6 of the base plate 2. An end portion of the discharge hole 12 adjoins a slight recess 13 located on the face portion 6 of the base plate 2. The discharge hole 12 and slight recess 13 allow materials to be discharged from an interior cavity of the mounting structure 1 during operation of the drilling pump. The materials may comprise waste and impurities generated during operation of the drilling pump.

Fig. 4A shows different views comparing an embodiment of the assembly with a prior art pump. The center-to-center spacing between adjacent cylinders is typically defined by the dimensions of the crankshaft used to drive the pump and the cylinder block. In the example of Fig. 4A, both the embodiment of the assembly and the prior art pump have a same center-to-center cylinder spacing, a fixed gap between cylinders at the cylinder block, and a same cylinder liner thickness. In this exemplary embodiment of the assembly, by reducing the amount of space needed to accommodate the mounting flange along the axis connecting the cylinder centers, cylinder liners with a larger inner diameter can be accommodated using the mounting structure disclosed. In contrast, the cylindrical mounting structure in the prior art can only accommodate cylinder liners with a smaller inner diameter, assuming the same center-to-center cylinder spacing, fixed gap between cylinders, and same cylinder liner thickness.

Fig. 4B shows different views comparing another embodiment of the assembly with a prior art pump. As shown in Fig. 4B, if the cylindrical mounting structure in the prior art were to accommodate cylinder liners with a larger inner diameter, this will require the center-to-center cylinder spacing in the prior art pump to increase, assuming a fixed gap between the cylinders. Thus, in comparison to the prior art, the assembly in this exemplary embodiment allows larger diameter cylinder liners and cylinders to be used while maintaining a same center-to-center cylinder spacing.

In the preceding specification, the invention has been described with reference to specific exemplary embodiments. It will, however, be evident that various modifications and changes may be made without departing from the broader spirit and scope of the invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded as illustrative rather than restrictive. Other embodiments of the invention may be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein.

Claims

An assembly for mounting cylinder liners, comprising:

a mounting structure comprising a base plate defining a hole and an internally threaded locating collar extending from the base plate around the hole, the base plate providing flange portions on opposite sides of the collar by which the mounting structure can be secured to a cylinder block; and

a locating ring configured to be located around a cylinder liner and having an externally threaded end portion, whereby when the locating ring is positioned around an end portion of a cylinder liner and engaged with the threaded locating collar, the cylinder liner is secured to the mounting structure.
The assembly of claim 1, further comprising a discharge hole located in a rim of the threaded locating collar, the discharge hole extending in an axial direction from a surface of the rim of the threaded locating collar to a surface of the base plate.
The assembly of claim 1, wherein the mounting plate has a width substantially similar to an external diameter of the locating collar.
The assembly of claim 1, wherein the assembly further comprises a gasket.
A method of mounting a cylinder liner in an opening formed in a cylinder block, the method comprising:

installing a gasket around the opening in the cylinder block;

locating an end portion of the cylinder liner in an internally threaded locating collar of a mounting structure;

positioning a locating ring around another end portion of the cylinder liner;

engaging an externally threaded end portion of the locating ring with the internally threaded locating collar of the mounting structure so as to secure the cylinder liner to the mounting structure;

positioning the mounting structure having the cylinder liner secured thereto on the gasket installed around the opening in the cylinder block; and

securing the mounting structure to the cylinder block by means of flange portions located on the mounting structure.
A pump, comprising:

a cylinder liner;

a piston located within the cylinder liner;

a piston rod connected to the piston and projecting from an open end of the cylinder liner; and

an assembly for mounting cylinder liners, comprising:

a mounting structure comprising a base plate defining a hole and an internally threaded locating collar extending from the base plate around the hole, the base plate providing flange portions on opposite sides of the collar by which the mounting structure can be secured to a cylinder block; and

a locating ring configured to be located around the cylinder liner and having an externally threaded end portion, whereby when the locating ring is positioned around an end portion of a cylinder liner and engaged with the threaded locating collar, the cylinder liner is secured to the mounting structure.