US1746733A - Pump piston - Google Patents

Description

C. LAMB PUMP PISTON Feb. 11, 1930.

Filed Feb. 26, 1927 2 Sheets-Sheet l C. LAMB PUMP PISTON Pub. 11, i930.

Filed Feb. 26, 1927 2 Sheets-Sheet 2 7 2 P 3 i fi 5 6 j \6 I 7 {J 7 {w r /w J fi a #6 5 fifi w a J F N if m 1 W B a y M P. p m 2 w flj r z Patented Feb. 11, 1930 UNITED STATES PATENT OFFICE CHARLES LAMB, OF LOS ANGELES, CALIFORNIA, ASSIGNOR F ONE-HALF TO M. G. BRUMBLY, OF WALNUT PARK, CALIFORNIA PUMP PISTON Application filed February 26, 1927. Serial No. 171,204.

Myinvention relates to pump pistons and particularly to a unique pump piston which is particularly adapted for use in pumpshandling fluid containing abrasives. My invention is suitable for use in slush umps such as are used in the oil producing in ustry.

In this industry a slush pump is utilized to pump rotary mud into the well during drilling and at other times. The rotary mud carries abrasive particles which rapidly wear away the packing of the ordinary piston.

There are slush pump pistons on the market today which are designed so that they may be mechanically expanded when the contacting wall thereof wears away. This arrangement is not entirely satisfactory, however, since adjustments must be frequently made to keep up the efficiency of the pumps. Furthermore, the cost of such a slush pump piston is exor bitant. 1 g

It is an object of this invention to provide a piston adapted for use in a slush pump which is simple in construction and economical to produce, and which is designed so that it will be automatically maintained in fluidtight relationship with the walls of thecylinder in which it operates, compensating for any wear thereon as it occurs.

Other objects and advantages of the invention will be made evident hereinafter.

Referring to the drawing in which I illustrate a preferred embodiment of the inven tion:

Fi 1 is a view of a slush pump utilizing a preferred embodiment of the piston of my 1nvention. I

Fig. 2 is a vertical cross-section through the preferred embodiment of my piston before it is installed in the pump.

Fig. 3 is a cross-section of the preferred embodiment of my piston as installed in a. pump.

Fig. 4 is an end view taken as indicated by the arrow 4 of Fig. 3.

Fig. 5 is a vertical cross-section through a. modified form of the piston of my invention before it is installed in a pump.

Fig. 6 is a vertical sectional view of the piston shown in Fig. 5, showing this piston installed in a pump cylinder.

Fig. 7 is an end view of the piston as indicated by the arrow 7 in Fig. 3.

Referring in detail to the drawing and particularly F ig. 1, the slush pump has a slush or driven end 11 and a steam or drive end 12. The slush end 11 has a cylinder 13 in which a piston 14 embodying the features of this invention is adapted to reciprocate. The piston 14 is attached to a piston rod 16 which extends outward from the cylinder 13 through a suitable gland 17. Referring to Figs. 2 to 4 inclusive, the details of the packer of the invention are as follows:

I provide a packer body 20 which is an integral structure and is preferably rubber or rubber composition which is first molded into the proper shape and then vulcanized. The body 20 has a cylindrical hub 21 through which a concentric tapered opening 23 is formed. The opening 23 is adapted to receive a tapered end 24 of the piston rod 16. Ex-

tending radially outward from the hub 21 at the central part thereof is a radial web 25. Formed at the outer end of the radial web 25 is a peripheral wall 26. The peripheral wall 26 has a central cylindrical portion 27 which is substantially the same diameter as the cylinder 13 in which it operates. The-opposite ends of the peripheral wall 26 are provided in the form of end lips 29. The end lips 29, as shown clearly in Fig. 2, are flared outward so that cylindrical edges 30, formed where outer faces 31 and end faces 32 meet, are of larger diameter than the cylinder 13. Formed between the ends of the hub 21 and the end lips 29 are annular channels 34. Formed in the inner part of the web 25 adjacent to the annular channels 34 are annular grooves 35. For the purpose of reinforcing and rigidifying the body 20 a central part thereof is made of firm, tough rubbeuas indicated at 37.

Adapted to enclose the ends of the hub 21 are metal caps 39. The metal caps 39 have perimetric walls 40 which surround and engage the ends of the hub 21 and which extend into the annular grooves 35. End walls 41 are adjacent to the end faces 42 of the hub 21 before the piston 14 is mountedon the piston rod 16. The caps 39 have tapered openings 43 through which the tapered portion 24 of the shaft 16 may extend.

In Fig. 3 the piston 14 is shown mounted on the end of the piston rod 16. The outer face of the left metal cap 39 engages a shoulder 44 of the rod 16. Screwed onto the end of the piston rod 16 isv a nut 45 which is adapted to force the right metal cap to the left so that the inner part of the body 20 is compressed and rigidly secured in place. The metal caps 39 forcibly engage the bottoms of the annular grooves and engage the end faces 42 of the hub 21 so that a fluidtight joint is provided which absolutely precludes any leakage 'through the piston 14.

When the piston 14 is placed in the cylinder 13, as illustrated in Figs. 1 and 3, the end lips 29 are compressed inward so that outer faces 31 thereof rest on the same circumferential line as the innerface of the cylinder. For this reason the end lips 29 will at all times exert a pressure against the cylinder which tends to maintain a tight seal between the piston 14-and the cylinder 13. During the operation of the slush pump the piston 14 is moved back and forth. When it is moved in either direction a pressure is built up on the sideof the piston in the direction in which it is moving and a pressure is built up in the annular channel 34 on the pressure side. It will be seen that the pres- I sure of the rotary mud or other fluid exerts a force outward against the adjacent end lip 29 of the peripheral wall 26 and thusassures that it will be maintained in very tight contact with the cylinder 13. When the piston 14 moves in an opposite direction a pressure is built up on the opposite side of it and the same thing occurs as just described.

The important feature of this invention is its simplicity. It is composed of three parts, each of which is simple in design and ma be produced at a very small cost. The vu canized body 20 may be ver cheaply and the metal caps 39 may ikewise e produced at a very small cost. The )arts may be formed separately and assembled afterwards, or the metal caps 39 may be first made and then placed in the mold with the body 20 vulcanized thereto.

The design of the vulcanized body 20 is such that a seal is automatically maintained between the peripheral wall 26 and the cylinder 13. This is very important to the inven tion since any leakage cuts down the efficiency of the pump a great deal. WVhen the body 20 becomes worn to such an extent that it will not serve its purpose'efliciently, it may be replaced at a very small cost. The fea: ture of providing the flared end lips 29 which are larger in diameter than the cylinder 13, and the feature of providing the annular channel 34 in which a pressure may be built up, are both conducive to a long-lived pump plston.

made

Another point in the construction of the invention, which is worthy of mention, is that the metal caps 39 are forced toward each other when the nut is screwed into place so that the vulcanized body 20 is clamped in place, this resulting in a tight seal which prevents a leakage of fluid through the piston 14. i

In some pumps the inner surface of the strain and hard wear that the modified formof piston shown in Figs. 5 to 7 has been produced. The piston 50 includes a piston body 51 which is preferably formed of a resilient material, such as rubber, in the same manner as the body 20 of the piston 14'and metallic end caps 52 and 53. The body 51 has a hub 55 and a web 56 extending radially therefrom. The peripheral surface 57 of the web 56 is substantially cylindricalin form and of the same diameter as the inner surface of the pump cylinder 13. Annular extensions 58 and 59 are provided on the web 56 so as to'extend longitudinally from the opposite edges of the peripheral portion of the web 56. The extensions 58 and 59 when unconstrained project outward to a diameter slightly greater than that of the web 56.

The packer body 51 has a reinforced core 60 which is formed of an especially firm,

tough rubber so as to minimize the displace- 52 and 53 in which it is shown in Fig. 5. The' caps 52 and 53 are thus retained in the relation shown by the inward rejection of the extensions 58 and 59 so that hese contact the radial outer faces of the flanges 62 and 63. as well as the peripheral faces of the hub engaging portions of the caps 52 and 5.3. The end faces 65 of the annular extensions 58 and 59 are concave in form for a purpose to be de-' scribed later.

A centralopening 66 is formed through the piston 50 so that it will fit the tapered end 24 of the piston rod 16 and be assembled thereon in the same manner as the piston 14. When the piston 50 is inserted into the cylin der 13, as clearly shown in Fig. 6, and recip rocated in the pumping operation, the liquid acts against one of the concave surfaces 65 on each stroke of the piston so as to force the corresponding annular extensions 58 and 59 outwardly into tight contact with the inner surface of the cylinder 13. In this action it is to be noted that as the piston 50 moves in the direction of the arrow 7, the annular extension 58 is expanded against the cylinder 13, thus causing a considerable increase in the friction between the cylinder 13 and the packer body 51. Also the pressure of the liquid against the surface 65 of the extension 58 forces this extension against the flange 62 of the cap 52. The flange 62 thus takes a large portion of the strain of the friction set up between the extension 58 and the cylinder 13. It is also to be noted that the longitudinal forces in the opposite direction of the arrow 7 which are set up by friction between the web 56 and the cylinder 13 are taken by the flange 63. Thus the flanges 62 and 63 cooperate to support the peripheral portion of the packer body 51 so that upon a stroke of the piston 50 in either direction of the cylinder 13 it is practically impossible to tear off or separate any peripheral portion of the packer body 51 due to the peculiarly hard working conditions imposed 011 the pump.

Under the hard working conditions referred to above the contact of the inward projection of the extensions 58 and 59 with the peripheral surface of the hubs 52 and 53 is of considerable importance. This contact prevents liquid exerting a pressure radially outward upon the annular extensions 58 and 59. It can readily be seen that where the friction between the piston 50 and the cylinder 13 is excessive. it is desirable that the extensions 58 and 59 should not be forced outward under too great a. pressure. This contact of the extensions 58 and 59 with the hubs 52 and 53 prevents the setting up of an excessive friction between the body 51 and the cylinder 13 which might cause a rupture of the packer body 51. Moreover, as pointed out above, the flanges 62 and 63 cooperate in such a manner as to support the peripheral portion of the packer bod 51 so that this will operate under extremely liard working conditions with no danger of rupture and with a minimum of wear.

I claim as my invention:

1. In a pump piston adapted for slush pumps, the combination of: an integral resilient piston body consisting of a hub having an opening therethrough. a web extended outward from said hub, and a peripheral wall at the outer part of said web, said peripheral wall having lips which are normally larger in diameter than the cylinder in which the piston operates, there being an annular channel formed between each of said lips and said hub; and metal caps on the ends of said hub.

2. In a pump piston adapted for slush pumps,

which are normally larger in diameter than the cylinder in which the piston operates, there being an annular channel formed between each of said lips and said hub; and metal caps on the ends of said hub.

3. In a pump piston adapted for slush pumps, the combination of: an integral resilient piston body consisting of a hub having an opening therethrough, a web extended outward from said hub, and a peripheral wall at the outer part of said web, said peripheral wall having lips which are normally larger in diameter than the cylinder in which the piston operates, there being an annular channel formed between each of said lips and said hub, said body having a middle reinforcing portion; and metal caps on the ends of said hub.

4. In a pump piston adapted for slush pumps, the combination of: an integral resilient piston body consisting of a hub having an opening therethrough, a web extended outward from said hub, and a peripheral wall at the outer part of said web, said peripheral wall having lips which are normally larger in diameter than the cylinder in which the piston operates; and metal caps on the ends of said hub.

5. In a pump piston adapted for slush pumps, the combination of on integral resilient piston body consisting of a hub having an opening therethrough, a web extended outward from said hub, and a peripheral wall at the outer part of said web, said peripheral wall having lips which are normally larger in diameter than the cylinder in which the piston operates, said body having a middle reinforcing portion; and metal caps on the ends of said hub.

6. In a pump piston adapted for slush pumps, the combination of: an integral resilient piston body including a hub having a central opening therethrough, a web extending outward from said hub, annular extensions formed longitudinally in opposite directions from the periphery of said web, said extensions. when unconstrained, being larger piston operates metal caps on the ends of said hub, said caps having substantiall radial flanges bearing against said opposite faces of said web, the annular extensions of said web extending inward into contact with the substantially radial outer faces of said flanges; and means for gripping said piston body between said caps.

8. In a pump piston adapted for slush pumps, the combination of: an integral resilient piston bod including a hub having a central opening t erethrough, a web extending outward from said hub, annular extensions formed longitudinally in opposite directions from the periphery of said web, said extensions, when unconstrained, being larger in diameter than the cylinder in which the piston operates; metal caps on the ends of said hub, said caps having substantially radial flanges bearing against said opposite faces of said web, the annular extensions of said web extending inward into contact with the substantially peripheral faces of hub engaging portions of said caps; and means for gripping said piston body between said caps. 9. In a pump piston adapted for slush pumps, the combination of: an integral resilient piston body including a hub having a central opening therethrough, a web extending outward from said hub, annular extensions formed longitudinally in opposite directions from the periphery of said web, said extensions, when unconstrained, being larger in diameter than the cylinder in which the piston operates; metal caps'on the ends of said hub, said caps having substantially radial flanges bearin against said 0 posite faces of said web, sai web extensions aving concave end faces; and means for gripping said piston body between said caps.

10. In a pump piston adapted for slush 7 pumps, the combination of: an integral resilient piston bod includin a hub having a central opening t erethro a web extending outward from said hu annular extensions formed longitudinally in opposite directions from the periphery of said web, said extensions, when unconstrained, being larger in diameter than the cylinder in which the piston operates; metal caps on theends of said hub, said caps having substantially radial flanges bearing against said opposite faces of sai web, the annular extensions of said web extending inward into contact with the substantially radial outer faces of said flanges, said web extensions 1 ha concave end faces; and means for gripping said piston body between said caps.

- 11. In a pum piston adapted for slush pumps, the com ination. of: an integral resilient piston bod includin ahub ha a central opening tlierethroug ii, a webez tz ding outward from said hub, annular extensions formed longitudinally in opposite directions from the periphery of said web, said extensions, when unconstrained, being larger in diameter than the cylinder in which the piston operates; metal caps on the ends of said hub, said caps having substantially radial flanges bearing against said opposite faces of said web, the annular extensions of said web extending inward into contact with the substantially peripheral faces of hub engaging portions of said caps, said web extensions having concave end faces; and means for gripping said piston body between said caps.

12. In a pump piston adapted for slush pumps, the combination of: an integral resilient piston body including a hub having a central opening therethrough, a web extending outward from said hub, annular extensions formed longitudinally in opposite directions from the periphery of said web, said extensions, when unconstrained, being larger in diameter than the cylinder in which the piston operates; metal caps on the ends of said hub, said caps having substantially radial flanges bearing against said opposite,

faces of said web, said piston body having a central semi-rigid reinforcing portion extending radially substantially from said opening to the periphery of said web; and

means for gripping said piston body between said caps.

13. In a pump piston adapted for slush pumps, the combination of: a resilient body; metal caps for the ends of said body; and radially disposed reinforcing members embedded in said body and connected to said caps.

14. In a pump piston adapted for slush pumps, the combination of: a resilient body, a central radial portion of which is formed of a materially tougher substance than end portions thereof; metal caps for the ends of said body; and radially disposed reinforcing members embedded in said body and connected to said caps.

15. In a pump piston adapted for slush pumps, the combination of: a resilient integral body, a central radial portion of which is formed of a materially tougher substance than end portions thereof, said body end portions, when unconstrained, being larger 1n diameter than the cylinder in which the piston operates; and means for mounting said body on a piston rod.

16. In a pump piston adapted for slushpumps, the combination of: a resilient integral body, a central radial portion of which is formed of a materially tougher substance than end portions thereof; radially disposed reinforcing members embedded in said body end portions; and caps for the ends of said ya 17. In a pump piston adapted for slush pumps, the combination of: a resilient integral body, a central radial portion of which is formed of a materially tougher substance than end portions thereof; radially disposed reinforcing members embedded in said body 6 end portions; and caps for the ends of said body, said caps being connected to said reinforcing members.

18. In a pump piston adapted for slush pumps, the combination of: a resilient in- 10 tegral body, a central radial portion of which is formed of a materially tougher substance than end portions thereof, said body end por-' tions, when unconstrained, being larger in diameter than the cylinder in which the piston operates; radially disposed reinforcing members embedded in said body end portions; and caps for the ends of said body.

19. In a pump piston adapted for slush pumps, the combination of: a resilient integral body, a central radial portion of which is formed of a materially tougher substance than end portions thereof, said body end portions, when unconstrained, being larger in diameter than the cylinder in which the piston operates; radially disposed reinforclng members embedded in said body end portions; and caps for the ends of said body, said caps being connected to said reinforcing members.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 21st day of February, 1927.

CHARLES LAMB.

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