US2981575A - Reciprocating pump cylinder head and liner retainer - Google Patents

Description

2 Sheets-Sheet 1 A. L. LEMAN III I I 1 l RECIPROCATING PUMP CYLINDER HEAD AND LINER RETAINER April 25, 1961 7 Original Filed May 2, 1956 April 1961 A. L. LEMAN 2,981,575

RECIPROCATING PUMP CYLINDER HEAD AND LINER RETAINER Original Filed May 2, 1956 2 Sheets-Sheet 2 N) a 1 55 5a 3 i: Q} LL x m I INVENTOR. ARTHUR L. LEMAN 6 BY QM, PLIJAQM ATTORNEYS United States RECIPROCATING PUMP CYLINDER HEAD AND LINER RETAINER Substituted for abandoned application Ser. No. 582,288, May 2, 1956. This application Apr. 24, 1959, Ser. No.

3 Claims. (Cl. 309-3) This invention relates to reciprocating pumps having cylinder liners such for example as those employed in the oil field and wherein alternating opposite pressures of substantial value are experienced. More particularly the invention aims to provide new and improved cylinder head structure and associated means whereby full positive steel-to-steel liner retainment is effected for such pumps, while relieving any elastic packing of axial stresses of the pumping operation and in a fashion such that the liner retainment need not be disturbed for piston inspection or replacement.

This application is a substitute for abandoned application Serial No. 582,288, filed May 2, 1956.1

In the drawings illustrating one embodiment of the invention:

Fig. l is a longitudinal central section through th head end of a reciprocating pump;

Fig. 2 is a corresponding partial end view of the cylinder head;

Fig. 3 corresponds'to a portion of Fig. 1, upon a larger scale; and

Fig. 4 is a fragmentary view upon a still and corresponding to a portion of Fig. 3.

In Fig. 1 the pump housing is designated generally at 5 and includes a cylinder 6 in which the piston (not shown) reciprocates. The cylinder liner assembly or unit, with the retainment of which the present invention is especially concerned. is indicated as a whole at 7.

This removable unit, whether a two-element assembly as illustrated by way of example or otherwise, is herein referred to as the cylinder liner or the liner. It is received in axially spaced cylindrical seats such as 8 in the cylinder opening. In the present example the liner 7 comprises an outer cylindrical shell 10 and a separable inner sleeve 12 within which the piston functions.

Suitable packing is provided between the liner 7 and the cylinder proper 6. With a liner arranged for backing off at the cylinder head end, as in the illustrated example, such packing is supplied at least adjacent said head end of the cylinder, and is herein designated generally at 15. It is shown asof the limited-pressure construction such as disclosed and claimed in my application Serial No. 481,082, filed January 11, 1955, now Patent No. 2,856,249, dated October 14, 1958. A collar 16 on the radially outer wall of the radially outer member or shell 10 of the liner unit 7 is received in and has opposed radial walls 21, 21, the inner of which longitudinally abuts a shoulder 17 of an annular recess in the cylinder 6. Such collar 16 presents oppositely in, clined longitudinal wall means as at 18, 18 defining with the cylinder wall cavities for conformant sealing annuli 19, 19. Consistent with the important feature of the invention whereby metal-to-metal liner retainment is bad with the single set of cylinder head studs and nuts 60,

larger scale 61, as hereinafter more fully explained, such limiteda pressure packing cireumferentially between the liner 7 ICC and the cylinder proper 6 may be variously located and arranged.

The illustrated liner shell 10 terminates somewhat short of the inner sleeve 12 and the latter receives upon the projecting portion a retainer ring 20 having endwise engagement with both parts 10 and 12 of the liner as at the proximate one of the radial walls or shoulders 21 on the collar 16 of the liner shell 10 and at a shoulder 13 on the liner sleeve 12. As more fully disclosed in said copending application the collar 16 of the liner presents inclined longitudinal wall means coactive with the packing such as 19, 19 to place it under radial compression, the parts being relatively dimensioned to afford axial expansion space for the packing while the wall means presents a longitudinal strut affording a positive stop as between the liner 7 and retainer ring 20 on the one hand and the cylinder 6 on the other hand, relieving the packing of excessive axial thrust.

Outwardly beyond the liner 7 the outer portion of the cylinder 6 defines an inlet-outlet chamber 9 within which is installed a liner cage 25 of outer diameter conformed to the cylinder and inner diameter adapted for passage of the piston and rod through it in the course of initial assembly or for changing worn pistons. The cage 25 has a series of radial ports 9a, 9a communicating with the flow passage 65:. This liner cage 25 is dimensioned to present in effect an axial extension of the retainer ring 20 with wall thickness adequate to transmit abuttive retaining thrust to and from said ring 20 and through the latter in solid metal-to-metal positive engagement with the cylinder liner 7.

The outer end or head of the cylinder comprises further novel structure completing full solid metal-to-metal, generally steel-to-steel, retainment of the liner. Such means at the same time eliminates the customary axial set screw used for. liner retention, instances of which are seen in my mentioned application and in. my prior Patent No, 2,640,434.

The liner retaining means herein comprises a flanged annular expander or sleeve designated generally at 30, including a cylindrical annular body 31 having an extension at the inner end presenting an abutment portion 32 with a radial inner end face 33 for directly abutting the adjacent radial end wall of the liner cage 25, in immediate metal-to-metal contact therewith. Said abutment 32 is circumferentially reduced as at 34 at an inclination to the cylinder axis to define with the surrounding wall of the cylinder a recess for an annular packing 35. The expander 30 with the liner cage 25 constitute a conjoint cylinder head element or pair in axial extension of the liner 7 and the retainer means 20 thereof. Said inclination of the peripheral wall 34 of the cage-abutting cylinder head extension 32 as illustrated is along a relatively fiat or low-angle taper toward the cage, illustrated as markedly less than 45 to the cylinder axis. Consequently said packing recess as defined by and between said fiat-taper wall 34, the radially opposite cylindrical wall of the cylinder bore and the adjacent outer end wall 33 of the cage 25 is of axially elongate wedge-shape tapering outwardly toward the opening head end of the cylinder. The annular packing 35 is cross-sectioned generally conformantly to said recess and similarly as the described packing 19 is relatively dimensioned to-afford axial expansion space, the packing having a free axial length less than that of the recess, as indicated by the dotted lining on Figs. 1, 3 and 4. In said figures. showing the parts locked up, some axial expansion of the packing 35 has taken place, but cavity space beyond the smaller .end of the packing remains as indicated at 34'.

Received concentrically within the cylinder 6 and the Patented Apr. 25,1961

head element 25-30 is a cylinder-closing plugor'hub 40. It is enterable through the expander 30 and has a tapered inner portion 41 forming with the enclosing wall of said element 2530, herein at the inner portion of the expander 30, a further recess for an annular packing or seal 42. Said packing-receiving space is further defined bytransverse means on said head element, illustrated as a radial shoulder 36 outwardly facingon the expander abutment portion 32, see particularly Fig. 4 and an oppositely facing lesser shoulder 43 on the cylinder-head closing hub 40. The latter is provided with a grip 44 by which it may be engaged for insertion and removal with respect to the cylinder.

Similarly as shown and described with reference to packing 35 and the receiving cavity therefor the annular wedge-Sectionpacking 42 is of lesser free axial length than the cavity therefor as above described, again as indicated by the dotted lining on Figs. 1, 3 and 4. While in said figures the packing 42 has been radially compressed and axially extended under locking up of the parts, it remains of lesser length than the cavity therefor, there being axial expansion space still available at the reduced end of the cavity as indicatedat 41 in said views.

The expander 30 is independently but demountably anchored on and with respect to the cylinder 6 and pump housing by means of a circurnfrential series of longitudinally projecting studs 60 set into the adjacent cylinder wall around the cylinder axis, similar to those of the conventional type of cylinder head. The expander 30 further comprises a relatively heavy radial flange 37 apertured for passage of the plurality of studs 60 and adapted to be generally secured in liner lock-up position by the corresponding plurality of nuts 61.

It will be particularly noted that the full thrusting force from these cylinder head studs and nuts 60, 61 is positively transmitted by continuous direct metal-to-metal extension through the expander 30, the liner cage 25 and the retainer ring 20 to the liner 7 itself. The retainer ring 20 is in effect an incorporated part of the liner and in some instances may be an integral portion thereof, particularly in the mentioned instance of a single-element liner, but with composite liners or with plural-recess pressure-limited packing between liner and cylinder as at a separate retainer ring is a distinct advantage and practical requisite. Thus in the pump operation forces tending to displace the liner in the cylinder are opposed by the described line of metal-to-metal retainment, while simultaneously affording limited compression of the elastic packing at the cylinder head, said limitation herein again had by reason of the free length of said packing ring 35 being less than that of the tapered .recess at 34 therefor similarly as detailed for packing 18.

The plug, hub or cylinder head proper 40 is held in the cylinder with capacity for separate removal independently of and without disturbing the expander 30 or having to remove the cylinder head nuts 61. For this purpose the thrust-transmitting expander 30 is provided with internal threading 33 of substantial longitudinal extent and preferably of rather steep pitch, for reception of the similarly threaded cylindrical outer face of a gland-like lock-up sleeve 50. The inner end of this head-securing sleeve 50 is adapted to abut and thrust against the outer face of the head plug 40 when the screwed gland 50 is turned in tight, simultaneously compressing the elastic packing 42 in both the radial and axial directions by reason of the described taper formation as at 41. The inner end portion of the hub or plug 40 is shown somewhat larger in diameter than the adjacent in-flanged end 32 of the expander ring 36 as seen at 46; see Fig. 1, also Figs. 3, 4. Thus the hub 40 has positive longitudinal abuttive engagement of said end portion 46 thereof with the cage and expander head element -30, herein directly with the expander member 34 thereof, at a position axially opposite the outfacing radial wall 36 of said expander inner end 32, as appropriate to relieve the packing of excessive compression and pressure; Desirably the outer end portion of the independent threaded gland or lock-up element 59 is provided with engaging formations for application of a tool to turn it for installation and removal, such for example as the pairs of radially opposite apertures 51, 51 adapted to receive a turning bar.

From the description in connection with the drawings it will be understood that the disclosed construction, relative proportioning and arrangement of the annular packings such as 35 and 42 and the receiving cavities there for represent an important aspect of the invention whether considered independently or in conjunction with the particular cylinder head and liner illustrated and wherein the cylinder 7 is rigidly held against endwise movement in the operation of the pump even under the relative high alternating pressures experienced with deep well pumping. The liner may be thus securely locked in position under full steel-to-steel retainment which retention need not be disturbed save for the relatively infrequent liner replacement as compared with the requirement for piston inspection or replacement. For the latter purpose the threaded gland 50 may be separately removed by backing it out from the expander and extracting the plug hub 40 as by engagement of the grip 44, affording access to the packing 42 and enabling the piston and rod to be removed and reinserted through the cage 25 and the cylinder head opening, with corresponding saving of time and effort as compared with having to remove the cylinder head stud nuts.

My invention is not limited to the particular embodiment thereof illustrated and described herein, and I set forth its scope in my following claims.

1 claim: g

1. For a reciprocating slush pump, a cylinder and head assembly comprising a piston cylinder with a cylindrical bore having an opening head end and adjacent thereto an internal annular shoulder presenting a radial outfacing Wall, removable liner means in the cylinder bore having adjacent the head end an integral radial projection for oppositely abutting said cylinder radial wall, a liner cage in the cylinder bore outwardly of and in longitudinal alignment at the inner end with the outer end of the liner means, one of said cage and liner ends carrying concentric annular means providing continuous metal-to-metal abuttive thrusting relation for the liner means and cage with each other at the adjoined ends thereof and also directly with the cylinder through said directly abutting liner and cylinder radial walls, and a cylinder head comprising a tubular cylindrical body entering the cylinder bore and centrally carrying head-end closure means for the cylinder, said head body having an inner extension in direct longitudinally abuttive metalto-metal contact with the cage and having an external flange carrying a single circumferential set of studs for securing the head to the cylinder end wall, the outer peripheral wall of said inner extension of the cylinder head body being inclined along a low-angle axially elongate taper toward the cage such that the radially opposite wall of the cylinder bore together with said inclined wall and the cage outer end wall define between them an axially elongate wedge-shape packing recess tapering outwardly toward the cylinder head end, said recess containing a resilient packing annulus of conformant wedge-shaped cross-section and of lesser free length axially than the length of the recess. Y

2. A cylinder and head assembly for a reciprocating slush pump according to claim 1 wherein the inner extension of the cylinder head body has at the cage-abutting end a radially inwardly extending shoulder presentingran axially outfacing radial wall, and the closure means of the cylinder head body comprises a cylinderclosing hub coaxially received in the head body with the hub inner portion in direct metal-to-metal longitudinal abuttive contact with said outfacing wall thereof together with a gland-like sleeve threaded into the head body and locking up the hub in said abuttive contact.

3. A cylinder and head assembly for a reciprocating slush pump according to claim 2 wherein the peripheral wall of the inner portion of said cylinder-closing hub is itself inclined along a low-angle axially elongate inward taper so terminating inwardly at the inner end of said hub as to provide for said hub end a larger diameter than the inner diameter of the radial shoulder of the inner extension of the cylinder head body thereby to effect said, longitudinal abuttive contact therewith, said inclined wall of the closure hub together with the radially opposite longitudinal wall of the cylinder head body and with the radial shoulder of the inner extension thereof defining between them an axially elongate wedgeshape packing recess, and there being in said recess a resilient packing annulus of conformant wedge-shaped 6 cross-section and of lesser free length axially than the length of the recess.

References Cited in the file ofthis patent UNITED STATES PATENTS 2,384,386 Malmberg Sept. 4, 1945 2,537,249 Walton Jan. 9, 1951 2,584,100 Vecker Jan. 29, 1952 2,584,518 Walton Feb. 5, 1952 2,717,186 Campbell Sept. 6, 1955 2,732,809 Mattingly et al. Jan. 31, 1956 2,757,056 Head July 31, 1956 2,856,249 Leman Oct. 14, 1958

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