US2204626A - Pump liner - Google Patents

Description

June 18, 1940. p L SCOTT y 2,204,626

PUMY` LINER Filed Nov. 12, 1936 @w www@ M//Y/ f m n N (nl 4vum'rao STATES PATENT OFFICE rumana@ secu. calmo, nl., saigner u su Dielel Tractor Corporation, La Porte, 1nd.. acorporation o! New York Application November iz, 193e, semina. 110.4114 s calm. (ci. :cs-4) This invention relates tothe construction/and the method of constructing a` barrel in which a member is Vto reciprocate and in which tight nts are essential. e l

l l The invention may be embodied in many constructions: One for which it is particularly well suited comprises a pump. When embodied in a pump the invention includes thepump barrel which is formed of a liner and a jacket or outer 0 member. 'I'he liner is perforated to receive a piston which may reciprocate within it. The

i invention is not limited in its application to a pump and where applied to a pump it is not limited to any particular forni or Aconstruction i5 of pump. Therefore, inthe present drawing,

which illustrates two forms of a pump barrel construction, only so much of the pump is shown as to indicate the general arrangement of the parts.

An object of `the invention is to provide means i whereby the pump liner is put under initial compressior, that is to say, vwhereby it is compressed initially before use.V Another object of the invention is to provide a pump barrel in which the tendency to distortion of the liner is overcome and in which any growth of the metal of the liner which occurs will be largely inwardly, tending thus to close the bore against. the. piston or plungerso that during the lift of the pump the bore does not growlarger and leakage is thus B0 avoided.

Another object is to provide a method of. manufacturing 4 a pump or other barrel having the properties described.

j Other objects will appear from time to time 85 in the specication and claims.

The invention is illustrated more or less diagrammatically in the accompanying drawing, whereinl Figure 1 is a longitudinal section through a 40 portion of a pump and pump barrel, illustrating one form of the barrel construction; and

Figure 2 is a similar sectional detail illustrating a modiiied form of barrel construction.

Like parts are designated by like characters 45 throughout the specification and drawing.

l is a portion of a pump housing which is prov vided with a cavity 2. 'I'he housing may have ears or other lateral projections 3, perforated as at to receive fastening means by which the 60 pump `may be secured to any desired base. Adjacent its upper end the pump housing i is provided with an inwardly extending part which partially closes the cavity 2 at that end. The portion B-may be shouldered as at 6. 55 Ihe barrel construction includes in general a plunger enclosing and guiding assembly including two parts, the first being a jacket or surrounding member 1 which is preferably provided with an inner tapered bore l and may have a laterally extending shoulder or iiange 9 of such I size as to be seated in the perforation or opening in the housing portion!` and being -seated also against the shoulder t. The jacket or surrounding portion may be of any suitable material but is preferably of one strongly resistant to .deforl0 mation, that is to s'ay, more resistant to deformation thanv the liner. Frequently in practice the jacket member may be of steel.

In the form of the inventionl illustrated in Figure 1 a liner i0 is provided. This liner ll has a cylindrical bore Il and its exterior is tapered as at i2, the taper corresponding to the taper I of the jacket 1. IWhile'the liner need not be ofthe same length as the jacket 1 it frequently is. The linery may also be ilared adjacent one end as at I3 to receive a sealing or joint-making member in a mannerv which4 will shortly be described.

In the form illustrated in Figure 1, i4 is a second housing portion' co-operating with` the 26- housing portion i in the formation of a com-A plete pump housing. A sealing member I5 is positioned partly in the flared portion I3 of the liner I! and partly in a ared portion ii made. at one end of the cavity or bore i1 within the 80 housing section I4. The details of the pump housing need not further be described and no description of the passages to and from the pump is necessary because the barrel of the present lnvention may be applied to almost any type of pump, or in fact to almost any construction in which a member reciprocates within a barrel.

In the form shown in Figure 1 a piston i8 is provided which iits tightly within the bore Il of the liner I0. This piston or plunger may be oi' 0 any desired shape but in thel form shown has a.

generally conical point i9. The plunger may be reciprocated by any desired means. vAs shown. however, the end of the plunger opposite the tapered end is rounded and adjacent this end there is formed an annular groove 20 into which is received a spring-retaining plate 2i. Asprlng 22 surrounds the barrel, bears at one end against the portion .t of the pump housing section i and L bears at the other end against the plate 2l. A 6o cross head 22a is mounted within the cavity 2 ofthe housing section i for reciprocation. It surrounds the plunger, barrel and spring assembly above described., 4It may carry a contact member 23 which fits within a perforation 24 in 55 in Figure 1 is ilanged as at 2 5 to.it-`again`st a corresponding shoulder formed in the bottom oi thev cross hea'd-.-Aspring 26 is sprung into a corresponding groove in the exposed end of the' member 23 to hold` it in place.

head of the plunger Il contacts the opposing sur:

face of'themember y23'. It will beunderstood that the cross head may be reciprocated by any mechanism. Itv moves upward in the form` shown in Figure i to compress the spring 22 .and yto force the plunger inwardly. When the spring is free for reverse movement vit forces the cross head and plunger downwardly. i f v Y.

In manufacture the materials chosen 'iriaaf'be for the liner a relatively soft material such as cast iron and for the jacket or sleeve .surrounds ingit a relatively harder material suchas steel. However, a liner. and sleeve assemb1y"can"be made satisfactorily .where both materialsare lof the same hardness. Thejclosing up which occurs when the sleeve is compressed on theiliner either by being drivenon in the tapered form or by being shrunk or pressed or otherwise tightened about the liner, may occur where both materials are oi the same hardness or have the same modulusof elasticity. InnormalV practice it is preferableto make the liner of a material having a greater modulus of elasticity thanv that of the sleeve but where it is desired the' sleeve and liner may have similar or identicalfmoduli of elasticity. y f

Cast iron has been spoken of as a suitable liner. Experience in the art of pumps has shown it to be a suitable material for many reasons. Experience has also shown that cast iron changes both its shape and size in the course of time.

This eiect is sometimes called growth or vwarpage and forms a serious objection tothe use oi' the material `as a liner for the barrel of a pump crother analogous device, and`it is particularly objectionable where cast iron is to be used as a pump barrel for fuel pumps where relatively high pressures prevail. In those vforms Iof the present device in which cast ironia used it is selected for its many advantageous qualities. among which are goodbearing qualities, good wearingqualities andgood machining qualities.

The liner, whether it be of cast iron or of other suitable material is made to approximately suitable shape and is then inserted in a sleeve or Jacket of a material of high tensile strength. The

two partsmay beassembled by .means of the taper iit shown in the form of Figure l, the liner being forced into the tapered jacket or sleeve. producing a press iit and the liner is actually driven into the taper farther than it would readilygo. This press t produces a tension in the sleeve or jacket 1 and a corresponding compression in the liner i0 and preferably this compression will be made greater than the hydrostatic or other load which may be` applied in use internally to the liner.

Inthe form of the'device shown in Figure 2, a retaining sleeve or jacket 21 isl used. 'Its outer shape and contour are essentially the same as .that of the sleeve 1. Internally it is not tapered,

however, and it is. provided with a cylindrical bore. l The liner 28, which fits within it, also is not tapered on its exterior.l Interiorly it has a bore 29 which is preferably flared outwardly as at lll for the reason above `described in ccnnecf.

tion. with the flare Il in the liner lil. In' the manufacture ofthe form of the device shown The. roundedand required excessive amounts of time.

is because no way has previously been known 2.204,0@ y l its bottom. This member in the form shown in lligure'ittiielier; which maybe of cast iron or other suitable material, is iltted and positioned within the sleeve 21 which may be of, steel or other material of 'high tensile strength with a shrink fit or a press fit or otherwise, so that tenlsion is produced in the sleeve `and-compression in the ylinen'llhe'restuts'i'f'- this form of con'- struction' are generally the same, therefor-aas those of the form of Figure 1 and the eiIect of each is to produce a compression ofthe liner before use and to vproduce a construction in which growthf or other change in the shape or size of the liner cannot occur to as great an" extentoutwardly and cannot result, therefore.

in an enlargement of the bore, and any such 'growth which may occur will be largely inward away from the plunger and thus to produce leakage. I

Heretoiore an accurate mating between a plunger and barrel in a packingless pump, that is too say, in which the main sealing eiiect is obtained .by the.' nicety of fit between a plunger and barrel of relatively hard materials rather than by soft and easily compressible materials, has proved a very, serious problem. General practice has involved hand lapping operations to extreme accuracies which has proved both costly This to handle these hard materials except by some form of cutting or abrasion. My invention overcomes this diillculty in that even though the materials are hard they do have slight elasticity and I am taking advantage of this slight elas-` ticity to change the size a minute amount which, however, is suflicient to produce the desired fit.

l. In combination in a pump having a barrel and a piston, a multi-part barrel having a cy- Alindrical bore, adapted to receive a piston, one of said parts comprising a unitary, ferrous liner, a second part situated outside of said liner and acting thereupon, said second part being fixed .with relation to said liner during pump operation and exerting a predetermined degree vof initial compression upon said liner said compression reducing the diameter of the bore of said liner -in minute amount and causing it tio fit and mate with the plunger to microscopic accuracy and producing stresses within the mav terial of said liner which stresses are well within the elastic limit of the material used;

2. In combination in a pump having a barrel and a piston, a multi-part barrel having a cylin-` drical bore, adapted to receive a piston, one of said parts comprising a unitary liner formed oi.' hard metal, a second part situated outside of said liner and\acting thereupon, said second part being ilxed with relation to said liner during pump operation and exerting initial compression'upon said liner and producing stresses within the material of said liner, said compression causingl 1 within the material of said liner stress greater than that produced therein by internal 'loading during normal operatonof the pump.

3. In combination in a pump having a barrel and a piston, a multi-part barrel having a cylindrical bore, adapted to receive a piston, one of said parts comprising a unitary liner, and being formed of a relatively hard material having a tendency to grow, a second part situated out-n annessa side of said liner and acting thereupon.. said second part being xed with relation to said liner during pump operation and exerting initial coml pression upon said liner and producing stress acting thereupon to compel said "growth to occur largely inwardly, said second part exerting initial compression upon said liner and producing stress within the material oiIv said liner.

5. In combination in a pump having a barrel and a piston, a multipart` barrel having a cylindrical bore, adapted to receive a piston, one of said parts comprising a unitary liner formed of relatively hard metal and being exteriorly tapered, a second part correspondingly interiorly tapered situated outside of said liner and acting thereupon., said second part being fixed with relation to said liner during pump operation and exertingy initial compression upon said liner and producing stress within the material of Vsaid liner. 4

6. In combina-tion in a pump having a barrel and a piston, a multi-part barrel having a cylindrical bore, adapted to receive a piston, one of said parts comprising a unitary liner formed of relatively hard metal and beingexteriorly tapered, a second part correspondingly interiorly tapered situated outside of and in contact with said liner and acting thereupon. said second part being iixed with relation to said liner during pump operation and exerting compression initially upon said liner and producing stress within the material of said liner.

7. In combination in a pump having a barrel anda piston, a multi-'part barrel' having a cylin-J drical bore, adapted to receive a piston. one ot said parts comprising a liner of one modulus oi elasticity, a second part situated outside of said liner and acting thereupon, said second. part being fixed with relation to said liner during pump operation and having a lower modulus of elasticity than said liner and exerting compression upon `said liner and producing stress within the material of said liner.

8. In combination in. a pump having a and a piston, a multi-part barrel. one of said parts comprising a liner, a second part situated outside ot said liner and acting thereupon. said second part exerting compression upon saidliner and producing strass within the'materiai of said liner, said liner being of a material having a greater modulus ot elasticity than that of the outer member of the barrel.

9. In combination in a pump having a barrel and a piston. a multi-part barrel. one of said parts comprising unitary a liner formed of relatively hard iron, a second part formed of relatively harder steel situated outside of said liner and acting thereupon, said second part exerting A compression initially upon said liner; and prducing stress withinl the material of said liner.

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