US2404835A - Crosshead - Google Patents

Description

July 3@, 1946.. i R FREUND 2,404,835

CROSSHEAD Fil-ed Jan. 22, 1945 INVENTOR c R.R. FREUND ATTORN S Patented July 30, 1946 UNITED STATES PATENT OFFICE CROSSHEAD,

Robert R. Freund, Phillips, Tex, assignor to Phillips Petroleum Company, a corporation of Delaware Application January 22, 1945, Serial No. 574,015

10 Claims. (01. 103-1) This invention relates to crossheads. In one of its more specific aspects its relates to a pump crosshead carrying a plunger in which the plunger is removable without disturbing the alignment of the crosshead bearings, or causing the bearing surfaces of the bearing shoe on the crosshead and on the slide therefor to touch any surface not touched in normal operation of the pump during the pumping stroke. In another specific aspect it relates to a crosshead assembly in a duplex plunger pump which allows removal of the plungers without breaking down the crosshead assembly.

Much difficulty has been experienced in prior art in repairing pumps because the removal of the plungers is impossible without disaligning the crosshead or crosshead assembly. In moving the crosshead out of its usual pumping position, it is easy for an unskilled worker to scar the bearings with resulting wear. The reassembly of the crosshead in proper position requires the skill of a millwright. Even a skilled worker finds the reassembly and adjustment of the crossheads to be a time consuming operation.

The present invention avoids moving the crossheads from their bearing surfaces and reduces the number of operations necessary to take out a plunger. In relation to a 3" x 10" Worthington duplex plunger pump, as an example, the saving in time amounts to five man-hours per plunger which is more than 65% of the time needed.

One object of the present invention is to facilitate the repair of a pump.

Another object is to avoidscarring'the bearing surfaces. to save time, to allow the employment of unskilled workers, and to avoid having to align the crossheads after replacing a plunger.

Another object is to make the plunger readily removable through the crosshead.

A further object is to provide a novel and useful construction of parts of a pump as shown, described, and claimed.

Numerous other objects and advantages will be apparent to those skilled in the art upon reading the accompanying specification and looking at the accompanying drawing.

In the drawing:

Figure 1 is a cross-sectional elevation taken through a plunger pump crosshead embodying the present invention, taken along the line l-l of Figure 2.

Figure 2 is an elevational view with parts in cross section of the crosshead and plunger assembly of Figure 1;

Figure 3 is an elevational view of the cover plate used in the structure of Figure 1.

Figure 4 is a plan view with parts broken away of a crosshead and plunger assembly for a duplex plunger pump embodying same crosshead construction as shown in Figures 1 to 3 inclusive.

In Figure 1 a pump frame 6 may be provided with a bushin l which is generally made of brass or bronze. for guiding a crosshead operating means which may comprise a driving rod 8. Mounted on frame 6 is a pump cylinder 9 in which it is customary to reciprocate a pump plunger 1 l.

While a pump plunger I l is shown, it is obvious that a piston could be employed instead of plunger I l and that this piston could have piston rings sealing to cylinder 9 without changing the principle of the present invention and, therefore, the word plunger as used in the claims is intended to cover all usual types of pistons and plungers.

When the invention is applied to a plunger type pump, as shown, it is customary to have a stufiing box l2 with the usual gland I 3 sealing between the plunger I I and the cylinder 9. a

In order to align and guide the plunger II it is customary to provide a crosshead. In the present invention this crosshead I4 is provided with a bearing shoe l6 having a bearing surface I! which slides in reciprocation on slide I8, as shown in Figure 2.

Crosshead I4 i connected to crosshead operating rod 8 by means of crosshead end plate It, studs 2|, nuts 22, screw thread 23 on the end of rod 8 and lock nut 26.

In order to carry out the objects of the present invention, crosshead M is provided with a hole 26 which hole has the same axis as the axis of plunger ll. Hole 26 has a diameter greater than any diameter of plunger ll so that plunger ll may pass through hole 26 without any difiicult manipulation.

A cover plate 21 is provided having a boss 28. The boss has a sliding fit in hole 26 and cover plate 21 is provided with a recess 29 on its surface for the reception of the butt end 3| of plunger I I.

As shown in Figure 3, recess 29 and butt end 3| which has a sliding fit therein are both smaller than boss 28 which has a sliding fit in hole 2'6.

Easily disengageable means is provided for holding parts I4, 21 and H in assembled relation as shown in Figure l, and this disengageable means may consist of studs 32, nuts 33, and retaining ring 34. However, many other forms of disengageable clamping means exist in the prior art and any of these old disengageable means, or

similarly devised disengageable means, may be employed to hold parts l4, 2'1, nd I l assembled without departing from the present invention.

While not essential in all pumps, it is common practice to cool the plunger internally with a cooling fluid such as water and, therefore, in Figure 1 a means has been invented to allow for such cooling.

The cooling fluid enters through an inlet pipe 35 which is brought around to connect to an inlet passage 36 formed in'plate 21. The manner in which the inlet pipe 35 is supplied with fluid is not part of the present invention but the end of inlet pipe 35 is commonly either connected to a flexible rubber tubing which allows for movement of the crosshead, or pipe 35 may have its end tele-v scopingly arranged in a stationary pipe, in which case a usual stuffing box may be employed. (These arrangements are not shown.)

Plunger H contains an axial hollow cavity 3?. Plate 21 is provided with an outlet passage 38 into which a fluid distributing pipe 39 may be screwed or otherwise fastened for the purpose of forcing the cooling fluid to circulate down to the far end 4! of plunger H. The disposal of the cooling fluid after leaving outlet 38 is immaterial to the invention but may be done by means of pipe 42 which may be of similar construction as that described in relation'to pipe 35, The discharge cooling fluid may be thrown away or may be cooled and recirculated in a manner well-known to the art. I

In Figure 2 side rods '43 are shown in cross section but it should be understood that when only one crosshead I4 is employed that side rods 43 may, in some instances, be dispensed with as unnecessary.

In Figure 4 is shown a crosshead assembly gen erally designated as 44. This crosshead assembly is for a duplex plunger pump in which the two plungers H, ll are oppositely disposed and fit into oppositely directed cylinders, which cylinders are not shown. The advantage of this construction is to give a double action in that while one plunger l l is advancing and doing work the other plunger is being withdrawn, and on pulling the crosshead assembly 44 in the other direction the other plunger will then do the work.

In Figure 4 the two crossheads l4, M are connected together by side rods 43 and are held to the side rods by means of shoulders on the side rods and nuts .15. The other parts being similarly numbered and similar to those in Figure 1 will not be discussed further. 7

Operation The operation of the pump is similar to all other plunger pumps during the pumping cycle. Shoe it travels back and forth on bearing surface It in normal pumping operation from one extreme position to another extreme position and the distance between these extreme positions is of limited extent and isa distance shorter than the length of plunger H.

In order to remove plunger ll without moving surface i7 away from any position on bearing it beyond the two extreme positions it takes .in

normal pumping operation, the following sequence of operations may be employed.

Nuts 22 are unscrewed from studs 21 and plate 59 is pushed toward the left-hand side of the drawing. Nuts 33 and studs 32 are removed and plunger H and ring 34 are pushed to'the right side of the drawing as far as possible. If tube 39 is present it may be easily unscrewed with a wrench inserted between the butt end 3| and plate 21. When tube 39 is unscrewed it is moved to the right side of the drawing inside plunger II as far as possible.

Crosshead I4 is then carefully moved to its extreme pumping position, care being taken not to move it past the place that it has worn for itself in bearing surface l8 during normal pumping operation.

Pipes 35,and 42 are disconnected from plate 21 and end plate 21 is moved to the right until boss 28 has come out of hole 26. Plate 21 is then lifted upwardly and removed.

Crosshead I4 is then carefully moved on its shoe l6 along the bearing surface l8 to the extreme right-hand position that the crosshead takes in normal pumping operation as can easily be seen by the place it has worn for itself in surface 18. Plunger II is then removed to the left through hole 26 in crosshead l4 and upwardly out of the structure shown in Figure 1.

Plunger ll'and stufling box l2 may then be removed without having disturbed the alignment of the crosshead l4.

The installation of a new plunger or the return of plunger II obviously proceeds in an opposite manner from the above steps of disassembly and, therefore, it is not regarded asnece-ssary to describe such further operations.

In Figure 4 where there are two crossheads I4, 3

M connected by side rods 43 and nuts l5, the operations are performed first on one plunger II and then on the other plunger I l and at notime is it necessary to spoil the alignment of crossheads' l4, l4 andside rods 43 nor to otherwise disassemble the crosshead assembly 44.

It is obvious that I have provided apparatus for carrying out the above mentioned objects of the of cylinders; a crosshead assembly comprising a first crosshead, a second crosshead, and side members securing said crossheads together; a plunger operated by each said crosshead in cooperativerelationship with one of said cylinders;

and means for reciprocating said crosshead assembly in pumping; the improvern'entin which eachsaid crosshead has a hole of'a. diameter larger than anycross section of the plunger operated therebypa plate disposed in a position to cover said hole, and disengageable means securing said plate to said crosshead in said position and securing the plunger operated by said crosshead a in s d p t and to said crosshead, whereby said disengageable means may be' disengaged to allow removal of said plate and withdrawal of said plunger through said hole thereby avoiding disassembly of said crosshead assembly when removing a plunger. a I

2. The improvement of claim 1 in which the plunger is hollow and fluid cooled internally, said .plate having an inlet passage and an outlet passage for the cooling fluid, means to supply cooling fluid to said inlet passage, said inlet and outletpassages communicating with the hollow interior of said plunger, and a fluid distributing tube detachably secured to said cover plate and forming a continuation of one of said passages whereby circulation of said fluid inside said plunger is improved at the end of said plunger farthest from said cover plate.

3. The improvement of claim 1 in which the plunger is hollow and fluid cooled internally, said plate having an inlet passage and an outlet passage for the cooling fluid and means to supply cooling fluid to said inlet passage, said inlet and outlet passages communicating with the hollow interior of said plunger.

4. In a plunger pump having a cylinder; a crosshead, a plunger operated by said crosshead in cooperative relationship with said cylinder; and means for reciprocating said crosshead in pumping; the improvement in which said crosshead has a hole of a diameter larger than any cross section of the plunger operated thereby, a plate disposed in a position to cover said hole, and d sengageable means securing said plate to said crosshead in said position and securing the plunger operated by said crosshead against said plate and to said crosshead, whereby said disengageable means may be disengaged to allow removal of said late and withdrawal of said plunger through said hole thereby avoiding movement of said crosshead beyond the normal extreme positions of said crosshead due to said reciprocation in pumping.

5. The improvement of claim 4 in which the plunger is hollow and fluid cooled internally, said plate having an inlet passage and an outlet passage for the cooling fluid, means to supply cooling fluid to said inlet passage, said inlet and outlet passages communicating with the hollow interior of said plunger, and a fluid distributing tube detachably secured to said cover plate and forming a continuation of one of said passages whereby circulation of said fluid inside said plunger is improved at the end of said plunger farthest from said cover plate.

6. The improvement of claim 4 in which the plunger is hollow and fluid cooled internally, said plate having an inlet passage and an outlet passage for the cooling fluid and means to supply cooling fluid to said inlet passage, said inlet and outlet passages communicating with the hollow interior of said plunger.

'7. In a pump the combination comprising a crosshead, a cylinder, a plunger in cooperative relationship with the crosshead and the cylinder,

the crosshead having an opening larger than the cross sectional area of the plunger, a plate blocking passage of said plunger through said opening, and disengageable means securing said plate to said crosshead and said plunger to said plate and said crosshead in said cooperative relationship and disengageable to allow removal of said plate and passage of said plunger through said opening.

8. The improvement of claim 7 in which the plunger is hollow and fluid cooled internally, said plate having an inlet passage and an outlet passage for the cooling fluid, means to supply cooling fluid to said inlet passage, said inlet and outlet passages communicating with the hollow interior of said plunger, and a fluid distributing tube detachably secured to said cover late and forming a continuation of one of said passages whereby circulation of said fluid inside said plunger is improved at the end of said plunger farthest from said cover plate.

9. The improvement of claim 7 in which the plunger is hollow and fluid cooled internally, said plate having an inlet passage and an outlet passage for the cooling fluid and means to supply cooling fluid to said inlet passage, said inlet and 7 outlet passages communicating with the hollow interior of said plunger.

10. In a pump the combination comprising a crosshead, a cylinder, a plunger in cooperative relationship with the crosshead and the cylinder, a bearing having a bearing surface of limited extent secured to said cylinder, said crosshead having a bearing shoe slidable on said bearing surface between two extreme positions in normal operation of said pump while said cooperative relationship is maintained, the crosshead having an opening larger than the cross sectional area of the plunger, a plate blocking passage of said plunger through said opening, and disengageable means securing said plate to said crosshead and said plunger to said plate and said crosshead in said cooperative relationship and disengageable to allow removal of said plate and passage of said plunger through said opening without separating said shoe from said bearing surface nor moving said crosshead beyond either of said two extreme positions.

ROBERT R. FREUND.

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