US2321927A - Packing device - Google Patents

Description

June 15,1943. c. J. MCCOY mL 2,321,927

PACKING DEVICE Filed Sept. 9, 1941 a I &\\\\\\\\\\ 26 imimumm\mm fl r1 g1 INVENTORS GAEL d- M? COY BY W/LL/AM 0. BUTLER THEIR ATTORNEY Patented June 15, 1943 UNlTED STATESPATENT OFFICE PACKING DEVICE Carl J. McCoy, Orcutt, and William 0. Butler, Santa Maria, Calif.

Applicaticn September 9, 1941, Serial No. 410,176 6 Claims. (Cl. 286-437) Our invention relates to packings for the piston rods of mud pumps, and the cleaning and lubricating thereof.

Reciprocating pumps of the character commonly used for circulating mud in oil wells during drilling operations are subject to excessive Wear due to contamination of the mud with sand and cuttings of a highly abrasive character. Particles of such sand and cuttings cling to the piston rods, and are carried into the packing; and rapidly destroy both the rod and the packing. Rubber packing is commonly used in an effort to exclude such abrasive matter from the packing, as much as possible. However, gland pressure necessary to effect a seal, under the high pressures which prevail during drilling, results in excessive friction. Such friction, in itself, is destructive to the packing and rod, be cause of inadequate means for lubricating the rods within the packing. In ordinary service, the useful life of the piston rods is about three weeks; and more frequent replacement of the packing is necessary. The cost of replacing the rods and packings is an item of considerable expense; and delays are sometimes caused, which are even more costly.

It is among the objects of our invention to provide a packing device for the piston rods of mud pumps which will effectually clean and lubricate the rods and packings, and prolong the useful life thereof.

Another object is to provide a device for supplying water or other lubricant to the pump rods at points intermediate the ends of the packing; and for utilizing pressure resulting from movement of the rods through the packing, for forc ing the liquid onto the rods at desired points.

A further object is to provide a packing and lubricating device which is simple and effective; and which may be readily installed upon pumps of ordinary construction,

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of our invention. It is to be understood that we do not limit ourselves to this disclosure of species of our invention, as we may adopt variant embodiments thereof within the scope of the claims.

In the drawing:

Figure l is a sectional view of our packing device, taken upon the line I-I of Figure 2, parts being shown in elevation.

Figure 2 is an end view of the packing box "I,

the gland 23 and fastening studs being omitted and parts being shown in section.

Figure 3 is an enlarged sectional detail of a portion of the packing device illustrating the condition that obtains during a pressure stroke of the piston. I

In terms of broad inclusion, the packing device of our invention comprises a resilient packing encircling a piston rod and provided with at least one chamber arranged to be alternately opened and collapsed in response to movement of the piston rod therethrough. Means are provided for feeding water or other-lubricant to the packing, for distribution onto the rod and into the chambers. During suction strokes of a rod, the water flows through the packing chambers and flushes out the packing. During pressure strokes, water trapped in the chambers is forced onto the rod at points intermediate the ends of the packing, under relatively high pressure produced by a collapsing of the chamber, due to the movement of the rod through the packing,

Our invention contemplates a structure comprising a rigid distributor ring having suitable channels and passages, and cooperating with resilient packing material encircling the rod contiguous with the ring for forming one or more collapsible chambers. Water is supplied to the distributor ring from any available source, at ordinary source pressure, through a connection provided with a check valve to prevent return flow. A check valve may be provided in the distributor ring to insure one way flow of water with respect to some of the chambers and passages. Means are provided for adjusting the degree to which the packing may be compressed by a packing gland, so as to allow an adequate range of movement of the packing in response to movements of the piston rod.

In terms of greater detail, the packing device of our invention, in its preferred embodiment, comprises a pair of resilient packing members or gaskets I and 2 encircling a piston rod 3 of a mud pump 4. The gaskets I and 2 abut against opposite ends of a distributor ring 6, which encircles the rod I between the packing members I and 2.

The distributor ring 8, which may be of metal or other suitable rigid material, fits relatively loosely over the rod 3 within a packing box I through which the rod extends. The ring 6 and gaskets I and 2 cooperate to provide one or more chambers 8, formed by recessing one or both of the contiguous ends of the distributor ring 6 and gaskets I and 2. The distributor ring 6 is re-.

cessed on its outer face, to form an annular passage 9; and upon the inner face of the ring to form an annular passage Ill. One or more passages II are formed in the distributor ring 6 to provide communication between the inner and outer passages 9 and I0. One or more passages I2 provide communication between the passages 9 and Ii] and the chamber 8 remote from the cylinder I3 into which the rod 3 extends.

A passage I4 in the packing box I provides communication between the passage 9 and a conduit [6 connected to any convenient source of supply for feeding water, or other lubricant, to the distributor ring 6. Preferably the conduit I6 is connected to any available source of water supply for delivering substantially clean Water under any ordinary degree of pressure. A check valve I1 is provided for preventing return flow of water from the ring 6 to the source.

The gasket 2 remote from the cylinder I3 is provided with an annular passage I8, alined with the adjacent ends of the passages I2. One or more passages I9 are arranged to conduct liquid from the passage I8 onto the rod 3 at points relatively remote from the cylinder I3. Where two chambers 8 are provided, as illustrated in the drawings, a passage 2| provides direct communication betweenthem. A check valve 22 is preferably provided in the passage 2i to prevent direct flow of water from the outer to the inner chamber.

The packing is compressed within the packing box 1 by means of a gland 23. The gland pressure is applied by nuts 26 engaging studs 2%. Nuts 27, engaging the studs 26, serve to hold the packing box I in engagement with the cylinder head of the pump 4. Nuts 28 are adjustable along the studs 26 to provide stops, limiting the inward movement of the gland 23; and providing means for adjusting the maximum pressure which may be applied for compressing the packing within the packing box.

The gaskets I and 2 are made of any suitable material resiliently deformable under high pressure, such as rubber. Under normal gland pressure, such as required to prevent leakage from the pump cylinder it along the rod 3, the gaskets i and 2 are compressed to give a tight fit on the rod 3, withoutcausing the gaskets to be compressed sufficiently to fillthe chambers 8.

In operation, water issupplied to the ring 8 under normal supply pressure, such as tap pressure from the ordinary water main. Water passing the check valve I! fills the passages 9, Ill and II, of the ringv 6. From the ring 6, the water flows to fill the chambers 8 and passages I9. The ring 6 fits fairly loosely in the packing box I, so that Water may flow around the ring to fill the chamber 8 nearest the cylinder I3.

At the beginning of a suction stroke of the piston rod 3, the packing members occupy a. position such as illustrated in Figure 1 of the drawing, with the chambers 8 open and filled with water delivered thereto through or past the ring 6.

As the piston is moved along its suction stroke, the friction between the rod and gaskets causes the gaskets to be crowded inwardly toward the cylinder end of the packing box. The partial vacuum produced in the cylinder causes the water to be drawn through the ring 6. and chambers 8 onto the rod. A substantial volume of water passes the ring 6 and enters the chamber 8 nearest the cylinder I3; and flows through the packing along the rod 3, as it is moved into the cylinder. Additional water is fed onto the rod through the passage I B, and also through the passages I9. Some water may also flow onto the rod at the juncture of the outer gasket 2 and ring 6. The combined flow of water thus directed onto the rod serves to flush out the packing and clean the rod of abrasive sand or cuttings; and to lubricate the rod during its suction stroke. The water so admitted enters the cylinder and is mixed with the mud which is being pumped.

During the return or pressure stroke of the rod 3, the frictional engagement of the rod and gasket I, coupled with the pressure developed within the cylinder and applied to the gasket I through th clearance 3| between the rod and the inner end of the packing box, serves to compress the gasket I against the ring 6. At the same time, and. by the same forces, the ring 6 is forced against the outer gasket 2. Due to such forces, the gaskets I and 2 are compressed sumciently to cause the ends of the gaskets to substantially collapse the chambers 8, as indicated in Figure 3 of the drawing.

Water trapped in the chambers 8 is displaced therefrom, and is forced under relatively high pressure onto the rod 3, as indicated by the arrows in Figure 3. The initial compression of the gaskets I and 2 against the ring 6 causes the edges of the gaskets contiguous to the ring to act as a valve, sealing in the water trapped in the chambers 8. Further compression of the gaskets I and 2, such as to collapse the chambers 5, causes the water to be displaced through the passages IQ onto the rod near the outer end of the packing. Water from the chamber 8 nearest the cylinder I3 is displaced through the passage 2|, past the check valve 22. The bulk of the water trapped {in the chamber 8 is thereby forced through the passages I9 onto the rod at the end remote from the cylinder, where the frictional wear is the greatest. The water so forced onto the rod serves as a lubricant, and materially reduces wear on both the rod and the packing.

As the rod 3 reaches the end of its pressure stroke, and begins its succeeding suction stroke, the resilient character of the gaskets I and 2 causes them to resume their normal shape, and to reopen the chambers 8 to receive water from the supply conduit IS. The flow of water onto the rod during the ensuing suction stroke of the rod causes any sand or cuttings to be flushed out of the packing. In this manner, the alternate opening and collapsing of the chambers 8, in response to movement of the rod 3, causes water to be directed onto the rod for flushing the packing during suction strokes; and for lubricating the rod during pressure strokes of the rod;

The packing device of our invention may be readily applied to pumps of more or less standard construction commonly used in drilling operations. Thus, the packing box and gland of the ordinary pump will accommodate. the packing of our invention; and all that is necessary to adapt such a pump to our invention, is to drill the passage I l and tap it to receive the connection IS. The normal range of adjustment of the gland 23 will permit the threading of the nuts 28 on the stud 26, to limit the movement of the glands, and thereby prevent the application of a gland pressure so great as to interfere with the opening and collapsing of the chambers 8 in response to movement of the rod 3'.

We claim:

1. A packing device for a piston rod, comprising a resilient packing encircling the rod and normally having a chamber therein collapsible upon movement of the rod therethrough, means for supplying a liquid to the chamber, a passage in the packing for conducting liquid from the chamber onto the rod under pressure produced when the chamber i collapsed, and means for preventing return of the liquid to the source of supply.

2. A packing device for a piston rod, comprising a resilient packing encircling the rod and normally having a chamber therein collapsible upon movement of the rod therethrough, means for supplying a liquid to the chamber from an external source, means for preventing return of the liquid to the source, a passage in the packing for conducting liquid from the chamber onto the rod under pressure produced when the chamber is collapsed, a gland engaging the packing, and means for adjusting the pressure exerted by the gland against the packing.

3. A packing device for a piston rod comprising a resilient packing encircling the rod and having a chamber the walls of which are movable to alternately open and collapse the chamber by movement of the packing in response to reciprocating movement of the rod therethrough, means for supplying water into the chamber from an external source, means for preventing return of the water to the source, and means for directing the water from the chamber onto the rod under pressure exceeding the pressure of the water supply and resulting from a collapsing of the chamber by force applied by the rod.

4. A packing device for a piston rod comprising a resilient packing encircling the rod and yieldable axially of the rod in response to movement of the rod through the packing, a distributor ring cooperating with the packing to provide a collapsible chamber within the packing, means for supplying liquid into the chamber through the distributor ring, means for preventing return of the liquid from the chamber to the source of supply, and a passage for directing liquid from the chamber upon the rod under pressure resulting from movement of the rod through the pack ing.

5. A packing device for a piston rod comprising a liquid distributing ring encircling the rod and having passages therein, a pair of resilient packing rings engaging opposite ends of the distributor ring and cooperating therewith to form chambers communicating with passages of the distributor ring, means for supplying liquid from an external source to the distributor ring and chambers, means for preventing return of liquid to the source of supply and passages in the packing for conducting liquid from the chambers onto the rod in response to pressure produced by movement of the rod through the packing.

6. A packing device for a piston rod comprising a liquid distributing ring encircling the rod and having passages therein, a pair of resilient packing rings engaging opposite ends of the distributor ring and cooperating therewith to form chambers communicating with passages of the distributor ring, means for supplying liquid from an external source to the distributor ring and chambers, means for preventing return of liquid to the source of supply, passages in the packing for conducting liquid from the chambers onto the rod in response to pressure produced by movement of the rod.- through the packing, a packing gland engaging the packing, and means for adjusting pressure applied by the gland to the packmg.

CARL J. MCCOY. WILLIAM O. BUTLER.

Images