US2760749A

US2760749A - Composite block for shut-off mechanism

Info

Publication number: US2760749A
Application number: US205539A
Authority: US
Inventors: James P Ratigan
Original assignee: J P RATIGAN Inc
Current assignee: J P RATIGAN Inc
Priority date: 1951-01-11
Filing date: 1951-01-11
Publication date: 1956-08-28
Anticipated expiration: 1973-08-28

Description

COMlPOSITE BLOCK FORSHUT-OFF MECHANISM James P. Ratigan, Los Angeles, Calif., assignor to J. P. Ratigan, Inc., Los Angeles, Calif., a corporation of California Application January 11, 1951, Serial No. 205,539 1 Claim. (Cl. 251-.-2)

This invention relates :to improvements over the shutoff mechanism disclosed in my copending application, Serial No. 672,352, filed May 27, 1946, now abandoned of which the present application is a continuation-in-part. The present invention concerns an improved form of sealing block for eifecting a shut-01f in the casing head of an oil well.

In the operation of oil wells it is the common practice to employ a pump located near the bottom of the well bore, the moving part of the pump being actuated by a string of sucker rods extending from the ground surface. The uppermost of these rods, called the polish rod, extends through the tubing and stuffing box, which permits the reciprocation of the polish rod relative to the tubing but prevents escape of oil around the polish rod.

It is frequently desirable to shut off the gas and oil pressure below the stufiing box, as for example, when it is desired to renew the packing in the stufiing box, and for that purpose a shut-01f mechanism is either associated with the stuffing box or is provided as a separate element disposed immediately below the stuffing box with valve members adapted to close about the polish rod to seal the space between the tubing and the polish rod and prevent the escape of gas and oil, even through the stufiing box may be removed or opened for repair.

It is an object of this invention to provide an improved form of sealing block for a shut-01f mechanism which may be employed in combination with a stuffing box connected to the flow tubing of oil wells.

Another object is to provide a sealing block of this type which employs a resilient sealing material attached and bonded in a novel fashion to a metal backing element.

Other objects and advantages will appear hereinafter.

In the drawings:

Figure l is a sectional plan view showing a shut-01f mechanism employing my improved form of sealing blocks.

Figure 2 is a sectional elevation taken substantially on the line 22 of Figure 1.

Figure 3 is a perspective view showing a preferred embodiment of my invention.

Figure 4 is a plan view having a portion taken sub stantially on the line 4-4 of-Figure 3.

Referring to the drawings, the shut-01f mechanism includes a body having a central vertical opening 11 and a transverse passageway 12 intersecting the opening. The transverse passageway 12 is preferably rectangular in cross-section. The lower portion of the body may be provided with threads 13 for connection to a well head. The upper portion of the body 10 may be threaded internally as shown at 14 for connection to a stufiing box. The polish rod 15 extends axially through the vertical opening 11. Means are provided for sealing off around the polish rod 15, and as shown in the drawings this means includes a pair of sealing blocks 16 mounted for sliding movement in the transverse passageportion.

way 12. These blocks are preferably identical, and as clearly shown in Figure 3 each comprises a rectangular block element 17 shaped to fit the rectangular crosssection of the passageway 12. A semi-circular groove 18 is provided in the forward face 19 of the block :element 17 for sealing contact with the polish rod 15. The groove 18 may be omitted if desired, particularly when the device is to be used for sealing off abouta wire line of relatively small lateral dimensions. Theelement 17 is preferably formed of yieldable rubber-like resilient mate-' rial. A metallic plate 20 having the same rectangular shape as the element 17 is secured to the rear face of the element 17.

In accordance with my invention, the rectangularplate,

20 is provided with a plurality of apertures'21 extending therethrough. Preferably the cross-sectional area of the apertures is not uniform throughout the length thereof, but on the contrary each aperture is necked in near the midpoint 22 of its length so that the outer ends of the apertures are of larger size than the necked down mid- The resilient block element 17 is molded on the plate 20 so that integral projections 23 of resilient material fill the apertures 21 from end to end. These projections 23 preferably terminate in a plane coincident with the end surface 24 on the metallic plate 20. The molding process also establishes a bond between the face 31 of the metallic plate and the face 32 of the resilien block 17.

Means are provided for moving the sealing block 16 from the inoperative position shown in Figures 1 and 2 to an operative sealing position in which the semicircular grooves 18 engage and encompass the polish rod 15. As shown in the drawings, this means includes jack screws 25 threaded into end caps 26. The end caps 26 are connected to the body 10 by means of tapered threads 27, which form a seal. A packing ring 29 may be mounted in the end caps 26 encircling the jack screws 25, and a gland 30 is threaded into each end cap for compressing the packing 29.

The jack screws 25 are each provided with a head 33 at the inner end and a groove 34 adjacent the head. The head 33 on each jack screw is received within a slot 35 provided in the face 24 of the metallic plate 20. The slot extends vertically to the upper end of the collar but terminates short of the lower end thereof. Parallel flanges 36 of relatively narrow width engage within the groove 34 on the jack screw 25. These flanges 36 extend to the bottom of the slot 35, but terminate short of the upper end of the slot. From this description it will be understood that when the jack screws 25 are turned in one direction the sealing blocks 16 are caused to move inward toward the polish rod 15, and when the jack screws are turned in the other direction the sealing blocks 16 are retracted away from the polish rod 15.

The resilient block elements 17 fit within the transverse passageway 12 rather closely, and after being compressed about the polish rod 15 to form a seal it may take considerable force to retract them into operative position. Accordingly, a rigid connection of high strength between the yieldable block element 17 and the metallic plate 20 is necessary. The projections 23 within the tapered apertures 21 in the plate 20 provide the necessary strength.

To assemble the block 16 into position within the transverse passageway 12, the end caps 26 are first removed by unthreading them from the body 10. The blocks 16 are then inserted into the ends of the passageway 12. The jack screws are advanced within the end caps 26 and the heads 33 placed in position within the slots 35 before the end caps 26 are re-engaged with the body 10. The end caps 26 may be screwed into the threads on the body without danger of disconnecting the Patented Aug. 28, 1956 heads 33 from-the slots 35 because the flanges 36 enter the grooves 34.

While in the foregoing I have illustrated and described the shut-off mechanism as applied around the polish rod, it will be apparent that ifthe polish rod or sucker rods aren'ot present or have been removed, a further tightening of the jack screws 25 will squeeze the resilient elements 17 together against each other to completely seal ed the vertical opening in the body 10. This seal can be effected whether the resilient blocks 16 are grooved at 18 or whether the groove 18 is omitted.

Having fully described my invention, it is to be understood that I do not Wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claim.

I claim:

In a shut-off mechanism for use on a well head, the combination comprising: a body member having walls defining a fluid passage extending therethrough, the body member also having walls forming a transverse bore of noncircular internal cross-section intersecting said fluid passage, a pair of noncircular rubber blocks mounted in said transverse bore on opposite sides of said fluid passage, each rubber block being shaped complementary to said bore and completely filling the bore, each rubber block having side faces slidably contacting the walls of the bore, each rubber block having a front face provided with a groove so that the confronting front faces of the rubber blocks are adapted to fit around a rod extending through the fluid passage, each rubber block having a rear face, a noncircular metallic plate fixed to the rear face of each block and completely filling the bore, the plate having edges flush with the side faces of its respective rubber block, a rotatable screw element threadedly engaging a threaded bore in a member fixed relative to said body, said screw element being connected with each metallic plate within the body member for sliding the rubber blocks toward each other along the transverse bore across said fluid passage into front face abutting relation, the rubber blocks being sufficiently deformable so that, in the absence of the rod, the rubber blocks may be advanced by the screw elements to deform the abutting front faces and bring the surfaces of the grooves into complete mutual sealing contact.

References Cited in the file of this patent UNITED STATES PATENTS 1,713,364 Arbon May 14, 1929 1,989,429 Segelhorst Jan. 29, 1935 2,144,403 Davidson Jan. 17, 1939 2,218,093 Penick Oct. 15, 1940 2,240,252 Bernstein Apr. 29, 1941 2,480,055 Seaton Aug. 23, 1949