Cylinder liner securing apparatus

A device for securing a cylinder liner (3) to a respective pumping module (2) in a reciprocating pump has a set of arrangements each with a hydraulically activated piston (8), a rod (11) of which is adapted to receive a nut (12), the retraction of which forcibly compels in attraction the cylinder liner (3) and the pumping module (2).

This invention is in the field of reciprocating pumps and particularly 
relates to a means for aligning and securing the cylinder liners of such 
pumps to their respective pumping modules. The means is also adapted to 
energise the seals of such liners. 
Reciprocating pumps are well-known and a particular example discussed in 
the present specification is oil-field mud pumps. The invention is not, 
however, limited to mud pumps but finds application in a variety of 
reciprocating or positive displacement pumps. 
In the past, there have been several different types of ways to attach 
cylinder liners to their respective pumping modules and these may vary 
according to make of pump in which they are used. One embodiment presently 
known employs a tapered concentric clamp, whale another uses a concentric 
screw clamping arrangement. 
It is important that the means for aligning and securing the cylinder 
liners may be implemented without undue effort and down-time. Cylinder 
liners are required to be changed frequently and this causes considerable 
inconvenience if the means and method for releasing the old cylinder 
liners and fitting the replacement cylinder liners are slow or difficult 
to operate. It has been found that existing systems or means for securing 
cylinder liners to respective pumping modules have been difficult to 
operate for a plurality of reasons, including the involvement of heavy 
components, the handling of which may be dangerous for operators. These 
systems also require considerable strength, skill and reliability of 
operators, together with the use of heavy tools in confined spaces. Yet 
further, the securing force is dependent on the extent of wear and the 
general condition of a plurality of the securing components. 
According to the invention, there is provided a means for securing cylinder 
liners to pumping modules in reciprocating pumps, wherein said means 
includes a plurality of arrangements having a piston slidable within an 
hydraulic cylinder, said pistons having a rod adapted to receive a nut, 
said rods extending outwith their respective cylinders and being passed 
through respective apertures in a member adapted to grip said cylinder 
liner, wherein retraction of said piston and nut causes said member to 
forcibly compel said cylinder liner towards said pumping module. 
Preferably, said arrangements are fastened to said pumping module. 
Preferably, said arrangements also include a spring or springs for 
location between the top of said cylinder and the piston. Hydraulic fluid 
can be inserted between the piston and the cylinder base by an external 
pressure source. 
Preferably, there are four or more said arrangements spaced at intervals 
about and externally of the circumference of the cylinder liner. 
Preferably, said means further includes non-rotational apparatus for 
preventing rotation of said pistons within said cylinders, wherein said 
non-rotational apparatus preferably includes one or more dowel rods which 
extend between said pistons and said cylinder base. 
Preferably said member comprises a clamping ring having corresponding 
apertures for receiving said piston rods.

A reciprocating pump generally described at 1 comprises a module 2 and 
cylinder liner 3. It is desirable that the cylinder liner 3 is securely 
held up against the face 4 of the module 2. Between the cylinder liner 3 
and the module 2 there is-provided a seal 5 which, in its unenergized 
(i.e., uncompressed) state, usually requires to be compressed by the 
cylinder liner 3, thereby a gap is created between the adjacent faces of 
the module 2 and cylinder liner 3. 
In order to prevent the existence of this gap, it is necessary to forcibly 
push the cylinder liner 3 against the module 2 and this is achieved by 
securing means, generally described at 6. The effect of compressing the 
cylinder liner 3 against the face 4 of the module 2 is to energise or 
compress the seal 5. This compression is of course desirable to increase 
the effectiveness and efficiency of the seal 5. The securing means 6 
comprises a plurality of assemblies 20, wherein each assembly includes a 
cylinder 7 adapted to house a slidable piston 8, a plug 9 and clamping 
springs 10. The piston 8 is further provided with a rod 11 which extends 
outwith the cylinder 7. The rod 11 is provided with a threaded portion 21 
adapted to receive the nut 12. Furthermore, the rod 11 passes through the 
shoulder or clamping ring 13 which circumnavigates the cylinder liner 3 
and is pressed up against the lug 14 on the cylinder liner 3. In a 
preferable embodiment of the invention, there is provided one or more 
dowels 15 which engage both piston end plug in each arrangement for the 
purpose of preventing rotation of the piston. 
In the embodiment shown, the securing means 6 includes four or more 
arrangements 20 having the aforesaid components 7, 8, 9, 10, 11, 12. These 
arrangements 20 are permanently bolted by the bolts 22 to the module 2, 
although the nuts 12 are detachable, thereby allowing removal of the 
cylinder liner 3. 
In use, when a cylinder liner 3 is positioned against or nearly against the 
module 2, the shoulder or clamping ring 13 is then fitted over each of the 
piston rods 11. The nuts 12 are then threadably applied to the rods 11. 
The method of forcibly securing the cylinder liner 3 to the pumping module 
2 is then implemented. This involves inserting hydraulic fluid 25 between 
the piston head 8 and the cylinder base, such that the piston is extended 
to a greater extent outwith the cylinder 7 and the nut 12 is given freedom 
to be tightened by further rotation along the piston rod 11 towards the 
clamping ring 13. Preferably, this process is performed with all of the 
securing arrangements 20 simultaneously. It should be noted that the 
apparatus and method described herein allows the nuts 12 to be tightened 
by hand. It will be appreciated that this is a considerable advantage over 
the requirement of using heavy tools which has been the practice in the 
past. 
The invention thus provides components which are considerably lighter than 
comparative components used heretobefore. In view of it negating the 
requirement of heavy tooling or handling, the components are less likely 
to be damaged during the removal or securing of cylinder liners and thus 
the invention permits greater repeatability and reliability. Furthermore, 
the need for intensive manual or skilled labour by operators is also 
mitigated. Similarly, there is a reduced danger of injury to operators or 
by-standers during such operational and maintenance functions. 
A further advantage of the invention is that the clamping pressure may be 
predetermined by the springs and it is possible to achieve uniform 
pressure around the periphery of the liner, which enables perfect liner 
alignment. 
Other advantages of the invention will become apparent to operators and 
associated personnel involved in the implementation and operation of the 
invention, including the fact that reduced time is required to affect the 
replacement of a cylinder liner. 
Further modifications and improvements may be incorporated without 
departing from the spirit or scope of the invention.