GB2306607A

GB2306607A - Securing an access cover to a reciprocating pump module

Info

Publication number: GB2306607A
Application number: GB9616606A
Authority: GB
Inventors: George Kennedy
Original assignee: Kennedy T M & Co Ltd
Current assignee: Kennedy T M & Co Ltd
Priority date: 1995-10-28
Filing date: 1996-08-08
Publication date: 1997-05-07
Also published as: GB9616606D0; GB9522117D0

Abstract

The access cover (3) is securely held on the pumping module (2) in a reciprocating pump by a set of arrangements (20) each with a piston (8) having a rod (11) coupled to a nut (12) seating in a locking plug (13) acting on the cover. The pistons (8) are hydraulically actuated against springs, to allow the nuts (12) to be screwed down on the rods (11), and then released to provide the force for securement. Dowels (15) prevent piston rotation.

Description

APPARATUS FOR RECIPROCATING PUMP5 This invention is in the field of reciprocating pumps and particularly relates to a means for securing the access covers of such pumps to their respective pumping modules. The means is also adapted to energise the seals of such covers.

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 vays to attach access covers to their respective pumping modules and these may vary according to the make of pump in which they are used. One embodiment presently known employs a concentric screw clamping arrangement, while another has a wedge device to lock the screw.

It is important that the means for securing the access covers may be implemented without undue effort and down-time. Pump internals are required to be accessed frequently and this causes considerable inconvenience if the means and method for releasing the access covers are slow or difficult to operate.

It has been found that existing systems or means for securing access covers 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 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 vear and the general condition of e plurality of the securing components.

According to the invention, there is provided a means for securing access covers 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 loed said access cover, wherein retraction of said piston and nut causes said member to forcibly compel said access cover 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 trapped between the piston and the cylinder base.

Preferably, there are three or more said arrangements spaced at intervals about and externally of the circumference of the access cover.

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 locking plug having corresponding apertures for receiving said piston rods An example embodiment of the invention vill nov be described by way example only, with reference to the accompanying Figure, in which Fig. 1 is a sectional view of an access cover and pump module incorporating the invention.

A reciprocating pump generally described at 9 Pg. 1 comprises a module 2 and access cover 3. It is desirable that the access cover 3 is securely held up against the face 4 of the module 2. Between the access cover 3 and the module 2 there is provided a seal 5 which, in its unenergized state, usually stands proud of the end of the access cover 3, thereby creating a gap between the adjacent faces of the module 2 and access cover 3.

In order to prevent the existence of this gap, it is necessary to forcibly push the access cover 3 against the module 2 and this is achieved by securing means, generally described at 4 Pug. 2. The effect of compressing the access cover 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 vith a rod 11 which extends outvith 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 locking plug 13 which is placed outwith the access cover 3 and is pressed up against the access cover 3. In a preferable embodiment of the invention, there is provided one or more dowels 15 which engage both piston and cylinder base in each arrangement for the purpose of preventing rotation of the piston.

In the embodiment shown, the securing means includes three or more arrangements 20 having the aforesaid components 7, 8, 9, 10, 11, 12, 15, 21. These arrangements 20 are permanently bolted to the module 2, although the nuts 12 are detachable, thereby allowing removal of the locking plug 13 and hence the access cover 3.

In use, when an access cover 3 is positioned against or nearly against the module 2, the locking plug 13 is then fitted over all of the piston rods 11. The nuts 12 are then threadably applied to the rods 11. The method of forcibly securing the access cover 3 to the pumping module 2 is then implemented. This involves inserting hydraulic fluid 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 locking plug 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 allovs the nuts 12 to be tightened by hend. 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 its negating the requirement of heavy tooling or handling, the components are less likely to be damaged during the removal or securing of access covers and thus the invention permits greater repeatability and reliability.

Furthermore, the need for intensive manual or skilled labour by operators is also negated. 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 selection of the springs and it is therefore possible to achieve predetermined pressure on the access cover which enables perfect sealing.

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 effect the replacement of pump internals.

Further modifications and improvements may be incorporated without departing from the spirit or scope of the invention.

Claims

WE CLAIM:

1. A means for securing access covers 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 pressurise the access cover, wherein retraction of said piston and nut causes said member to forcibly compel said access cover towards said pumping module.

2. A means as claimed in Claim 1 wherein the said arrangements are fastened to said pumping module.

3. A means as claimed in Claim 1 wherein said arrangements also include a spring or springs for location between the top of said cylinder and the piston.

4. A means as claimed in Claim 1 wherein hydraulic fluid can be trapped between the piston and the cylinder base.

5. A means as claimed in Claim 1 wherein there are four or more said arrangements spaced at intervals about and externally of the circumference of the access cover.

6. A means as claimed in Claim 1 further including 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 piston and said cylinder base.

7. A means as claimed in Claim 1 wherein said member comprises a locking plug having corresponding apertures for receiving said piston rods.