US1498610A - Packing for valves and pistons - Google Patents

Description

PACKING FOR VALVES AND PISTONS Filed June 17. 1922 2 Sheets-Shet 1 HARKY s. camaszonl, gnvcnfoz,

Marlena PACKING FOR VALVES AND PISTONS Filed June 17. 1922 2 Sheets-Sheet 2 5 N) i I l l HARRY acnmuzml 3MP Patented June 24 1924.

UNHTEE STATEfi HARRY S. CAMERON,

ean

OF HOUSTON, TEXAS.

PACKING FOR VALVES AND PISTONS.

Application filed June 17, 1922. Serial No. 568,986.

To all whom it may concern:

Be it known that I, HARRY S. CAMERON, a citizen of the United States, residing at Houston, Harris County, Texas, have inv vented a certain new and useful Improve-- ment in Packings for -Valves and Pistons,

of which the following-is a full, clear, and

exact description, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to piston packing. It is particularly adapted to furnish a packing for pistons in pumps or in 'piston valves where excessively high liquid or gas pressure must be controlled without appreciable leakage.

An object of my invention is to provide a construction of packing ring which will be automatically expanded by the pressure of the fluid being handled.

Another object is to provide a form of packing which may readily be fixed in position and which will withstand high pressures without leakage.

In the drawings, herewith, constituting a part of this specification, Fig. 1 is a view partly in section showing my packing applied to a piston valve in a blowout preventer. Fig. 2 is aside elevation of the said piston valve, Fig. 3 is a top plan section thereof; Fig. 4 is a front elevation of said piston; Fig. 5 is broken sectional detail showing my packing in use, and Fig. 6 is a perspective view of a short length of packing material embodying my invention.

I have illustrated in the drawing the application of my improved packing to a blowout preventer such as is illustrated in my copending joint application, Serial No.

552,522 filed April 14th, 1922. In such a device, it is necessary to prevent the leakage of fluids under excessively high pressures. Ordinary metallic or composition packing is entirely ineffective for this purto pose as pressures in excess of 2000 pounds to the square inch are sometimes encountered. I wish'it understood, however, that this packing may be employed in various other devices, without departing from the spirit of the invention.

The blowout preventer shown is merely a type of valve designed to fit about the drill stem used in well drilling and to prevent the passage of gas or liquid upwardly from the casing outside the drill stem to the atmosphere. It is designed to prevent the premature blowing in of a well as it is being finished.

In the drawing I have shown the blowout preventer as attached to the upper end of a casing 1. This casing is devised to retain the walls of the well being drilled; and the drill stem with the drill thereon is adapted to rotate down through the open casin in the drilling of the well. The upper end of the said casing is secured to the blowout preventer by means of a threaded connection at 7. The device comprises a housing for a two-part piston valve adapted to close the. space around the drill stem. There are two laterally extending. chambers 6, each of which houses a piston valve 8. The upper end of the housing is extended upwardly at 3. This upward extension may be provided with a short flaring length of pipe 4 to guide the drill into the casing and to pro-- vent mutilation of the threaded upper end. The pistons 8 are slidable to and from the center of the passage 5 through the casing and the housing so as to fit together about the periphery of the drill stem. To accomplish the forward and backward movement of the piston valve 8 the center of the said piston is hollowed out at 9 and is threaded) to the forward end 10 of a valve stem 11" which is provided with a squared outer end 12 by means of which it may be rotated.

There is a radial flange 13 on the said valvej stem fitting within an annular groove in the housing 6 and retained in position by means of a threaded washer or nut 14. To further provide against the leakage of liquid outwardly past the drill stem a stulfing box 15 of ordinary construction is formed about the valve stem in the outer end of the housing. This construction is all described and shown in my previous application above referred to.

It will be noted in this type of blowout preventer that when the valve is closed about, the drill stem so as to prevent the escape of gas or oil from the casing upwardly around the drill stem a particularly tight closure must be maintained to prevent the leakage about the valve. The two pistons 8 constituting the valve are formed with a semi-cylindrical forward face 16 shaped to exactly fit about the drill stem. There are on the, forward face of each of the pistons horizontally extending strips of packing 17 fitted within grooves 18 in the forward face. This is shown particularly in Fig. 4. By forcing these pistons under extremely high pressure against the drill stem the packing may be made to closely engage the pipe and prevent leakage along the outer surface of the pipe.

It is found tobe important, however, to extend the packing so as to make an abso lutely fluid-tight connection around the lower side of the pistons. The upward pressure of the gas and fluid against the lower portion of the valve will tend to force the valve upwardly in the cylinder or housing 6 in which it fits and tend to allow leakage around the lower half of the said piston. It is obvious that an ordinary packing such as is employed at 18 across the forward face of each of the pistons will be entirely inadequate. T have therefore devised the type of packing shown at 19 in Fig. 6. .This packing is formed of some wear-resisting material which is compressible and somewhat elastic. Tt is preferably made approximately square in cross section. On one of the flat faces thereof. and closely adjacent one edge, ll form a V-shaped groove 20. By forming this groove closely adjacent one edge as there shown I provide an outwardly tapering lip 21 along one margin which, may be forced laterally by fluid pressure exerted within the said groove.

In using this type of packing in connection with the piston valve shown in the drawing T form a channel or groove in the outer periphery of the piston. This groove .extends horizontally from the forward edge of the piston midway thereof backwardly to a point spaced somewhat from the rear edge thereof and from there the groove extends circumferentially around the lower side of the piston approximately 180 degrees to a point diametrically opposite the horizontal groove 22 and then again directly forward to the edge of the piston. This groove is shaped approximately rectangular when viewed transversely so as to tightly receive the packing 19. As the fluid pressure is exerted upwardly and rearwardly from the lower face of the piston it will be noted that the horizontal portion 22 and the circumferential portion 23 of this packing will effectively close off fluid pressure coming upwardly within the well between the dull stem and easing. Tn placing this pack ing within the channels in the piston the notch or groove 20 must be inserted so as to be presented toward the direction of 1 the.

' fluid pressure. Therefore, as shown in Fig.

4, the outer lip 21 will be presented down wardly adjacent the outer'edge of the hori-- raeaeio 1 zontal groove 22 and, as shown in Fig. 2, will be presented downwardly and forwardly adjacent the outer edge in the groove 23.

In the operation of my device the valves may be tightened about the drill stem in the usual manner so as to firmly compress the forward packing 18 about the pipe. The packing 19 which is driven into the channels 22 in one continuous piece along the sides and around the lower face of the pistonvwill tend to prevent the escape of fluid under pressure around the lower side of the piston. In Fig. 5 T have shown about the manner in which the fluid pressure will tend to automatically expand the packing and close the space between the piston and the inner walls of the cylinder. The fluid pressure will be exerted upwardly from below and will enter within the notch or groove 20 and will force the lip 21 outwardly against the inner wall of the cylinder and thereby tend to seal the space between the piston and cylinder so as to allow no escape of the fluid. It has been found by experiment that when the packing is thus grooved so as to allow the fluid pressure to expand the outer lip 21 and seal this space, in some instances pressure fifteen to one hundred times as great may be held back by the valve as can be done in the use of ordinary types of packing in which the groove is not formed.

I do not wish to confuse my inventive idea with the ordinary types of metallic or other packing having grooves therein to contain oil or other fluid tending to lubricate and seal the space between the piston and the cylinder. This invention has nothing whatever to do with that type of packing. The material of which this packing is made must necessarily be compressible and the slot or groove 20 must be presented forwardly toward the fluid pressure as shown in the drawing, so that the said pressure may enter the groove and expand the same as above set forth. This idea is therefore believed to be a very Valuable improvement in packing,

Having thus described my invention, what I claim is new and desire to protect by Letters Patent is: n

1. A packing means to close off fluid pressure between a piston and cylinder, com-' prisinga strip of compressible wear-resisting material adapted to fit within a longitudinal channel in the outer surface of said piston, saidpa cking having a groove cut on one face ad acent one side thereof so that fluid pressure will enter said groove from below and serve to expand the packing outwardly against the said cylinder.

2. packing means to prevent the as sage of fluid between tw o hormally stationary smooth surfaces, comprising a rectangulllltii lar strip of flexible packing material extending longitudinally of said surface and having a longitudinal shallow V -shaped groove-cut in one face near the edge thereof 5 'soas to form a sharp lip, said groove being presented in the direction of the fluid pressure whereby said lip will be forced outwardly against the adjacent wall in manner described.

In testimony whereof, I hereunto aflix my to signature this the 13th day of June, A. D. 1922.

the I HARRY s. CAMERON.

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