US2491599A - Seal assembly - Google Patents

Description

Dec. 20, 1949 H. ALLEN 2,491,599 SEAL ASSEMBLY Filed Aug. 18, 1947 /6 252/ /5 I I /z3\ M I A? l/J m; a 'lfl/ FIG. 2 4 m J ,/27

I -33 2 F F FIG. 5.

f 5 T ats 21% FIG. 3 5 2 ATTORNEYS Patented Dec. 20, 1949 UNITED STATES PATENT OFFICE 2,491,599 SEAL ASSEMBLY Herbert Allen,

of Texas Houston, eron Iron Works, Housto Tex.. asslgnor to Cam-.

n, Tex a corporation Application August 18, 1947, Serial No. 769,148 Claims. (Cl. 285-22) ing fluid under pressure between them.

Another object of this invention is to provide such a structure in which it will be possible to determine visually the distribution of pressure applied to various portions of the circumference of the device in forming such seals.

Another object of this invention isv to provide structure of the type referred to with means for applying at spaced points the seal forming pressure for forming the spaced seals between the well casing or the like and the casing head.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein are set forth by way of illustration and example and not by way of limitation two embodiments of the invention.

In the drawings:

Fig. 1 is a fragmentary view showing in vertical cross section a seal assembly constructed in accordance with this invention locatedin the upper portion of a casing head or the like;

Fig. 2 is a view similar to Fig. 1 but illustrating a modified form of the invention;

Fig. 3 is an enlarged view showing a portion of the structure illustrated inFig. 1 and illustrating in vertical cross section the means for indicating the pressure being applied to form a seal;

Fig. 4 is a view on an enlarged scale showing the pressure applying and pressure indicating means employed in the form of the invention shown in Fig. 2; and

Fig. 5 is a fragmentary plan view of a portion of the structure shown in Fig. 1, illustrating the disposition of the pressure applying and pressure indicating means forming a part thereof.

With more particular reference to the drawing, the numeral l designates the upper portion of the usual casing head having a flange 2 or other tapered surface forming a bowl 3 for the reception of slips 4 which are shown gripping a. casing 5 extending upwardly through the casing head and terminating at 6 a short distance above the casing head.

[0 and H may be provided on the upper surfaces of the flange 2 or the annular body 9 or both.

At one point of provided pose of this passage and a threaded opening leading thereto will be presently described.

The annular body 9 may if desired be provided with an upstanding purpose of which will be presently set forth.

The annular body 9 is illustrated as being provided on its inner surface with two spaced grooves it and iii respectively and on its outer surface with two correspondingly positioned spaced grooves 20 and M, respectively. The grooves i8 and it have located in them a pair of flexible sealing rings 22 and 221?, respectively, and the outer grooves it and ill have disposed within them likewise flexible sealing rings M and it respectively. In each case, however, these sealing rings are of such radial extent that they will be spaced slightly from the bottoms of their respective grooves.

At circumferentially spaced positions the grooves it, W, W and it are all interconnected by suitable passages in the annular member 9 as indicated at 26, thereby providing intercommunication between all of the grooves. Also, at circumferentially spaced points the annular body downwardly eating passageways tapped openings alternate between those such as indicated at 21 which extend only to the level of the uppermost of the grooves, and those such as 28 which extend on downwardly into communication with the passages in the annular body 9 at a level substantially that of the lowermost of the grooves. In each of the tapped openings 21 there is provided a screw type ram or plug 29 by which it is possible upon removal of the plug to fill the opening with a stiff plastic material fiowable under pressure and then to force such material into the grooves l8, I9, 29 and 21 by re-inserting the plug 29 and screwing it down into the tapped opening 21. In this manner all of the grooves and the passages communicating between them may be filled with a fiowable material under any desired pressure and this material will serve to urge the flexible sealing rings 22, 23, 24 and 25, respectively, into sealing engagement with the casing and with the inner surface of the casing head 1. Thus, there will be provided two vertically spaced seals between the annular body and casing and likewise two vertically spaced seals between the annular body and the casing head.

In order to prevent the possibility'of applying too little or too great a pressure upon the flowable material supplied through the tapped openings 21, each of the tapped openings 28 is provided with a pressure indicator in the form of a housing or body 30 having the interior construction shown in Fig. 3. It will be seen that the lower end of the housing or body 39 is provided with a partition 3| having a central opening therein which receives the lower end of a plunger 32, the lower end of the plunger 32 being thus exposed to the pressure within the passage that communicates between the respective grooves. In this instance it willbe seen that the housing 39 extends downwardly past the level of the uppermost sealing rings so that the pressure which it indicates'or to which it is subject will be that substantially at the level of the lower sealing rings. Other pressure indicators may if desired be provided which extend only to the level of the upper sealing rings as indicated in Fig. 4 and as will be presently described.

The plunger 32 of each indicator is provided with an enlargement 33 forming a stop limiting the downward movement of the plunger. The plunger is constantly urged downwardly by means of a spring 34 which surrounds it and bears against the upper surface of the enlargement 33, this spring at its upper end bearing against the lower surface of a nut 35 which in effect forms a part of the housing 39. The upper end of the plunger extends through an opening in the nut 35 and the area of the lower end of the plunger, the strength of the spring 34, and the length of the plunger are so proportioned with respect to the body 9 and the position which they are to occupy in the body 9 that when the desired predetermined pressure exists within the passages in the body 9 the upper end of the plunger will be substantially flush with the upper surface of the body 9.

Thus, it will be seen that the indicators such as just described provide an accurate means for determining the pressures existing at various points within the body 9 but these indicators are of such a nature that at no time when the pressures are not greater than they should be will any portion of the indicators project beyond the regular contour of the exterior of the body 9.

With reference to Fig. 5, it is contemplated by this invention that a number of theindicators such as just described will be located at various points about the circumference of the body 9 so as to provide visual indication to the operator of the pressures existing within the various portions of the body 9. Also, at alternate positions between the indicators referred to the body 9 will be provided with the tapped openings and rams 21 and 29. Thus, there will be a means of applying additional pressure to the fiowable material within the body 9 at a point or points adjacent each of the indicators and there will be an indicator adjacent each of the pressure applying means. If the material within the body 9 were a readily fiowable material such an arrangement would perhaps be superfluousbut in order to prevent extrusion of this material past the sealing rings 22, 23, 24 and 25 it is desirable that the material be of a very stiff fibrous nature presenting many of the characteristics H of a solid when not under pressure, and since such material fiows only very slowly when under pressure it would be possible without the arrangement just referred to or its equivalent to create a highly excessive pressure at one point in the system while at another point in the system the pressure would not be great enough to provide the necessary sealing force behind the sealing rings.

It is to be appreciated that while the invention is illustrated in connection with two spaced sealing rings both on the exterior and on the interior of the body 9, the use of the plurality of indicators and pressure applying means is not limited to this number or arrangement of sealing rings but may be applied to any arrangement in which one or more seals are to be provided by a fiowable material, whether sealing rings separate from the material itself are employed or not.

Referring back to the passageway I2 in the flange 2 and the tapped entrance thereto, it will be seen that this passage is so located as to lie between the levels of the upper and lower sealing rings carried by the body 9. Furthermore, the body 9 is provided at about the same level with one or more passageways 39 extending radially therethrough independently of the passages interconnecting the grooves. By means of this arrangement it is possible to inject through the passageway l2 and into the zones between the body 9 and the casing head'and between the rings 22 and 23 a testing fluid under pressure. This testing fluid is preferably liquid and will apply a pressure against each of the four seals formed by the four sealing rings, and b noting any leakage once this pressure has been fully applied it can be determined whether or not the seal provided by any of these rings is leaking. If a leak is noted, the pressure against the rings may be increased by tightening up on the respective plugs 29 in the manner hereinbefore discussed, and the seals provided by these rings may thereby be rendered more perfect for the purpose of eliminating any such leak.

Likewise, if it be desired to provide a welded connection between the body 9 and the casing at the point It, such a welded connection may be tested by the injection of a testing fiuid under pressure through the port l1.

As an alternate to the construction just described, the casing head may be in the form of that indicated in Fig. 2 at 10!. The slips 4 and the casing 5 in this figure are identical with the 7 corresponding elements shown in Fig. 1, but instead of being provided with a smooth cylindrical bore or zone adjacent its upper end the casing head MI is provided with a coarse threaded zone I01 terminating in a shoulder I08 at its lower end. The annular body the body 9 of Fig. 1, is likewise provided with threads on its outer surface for engagement with those formed in the casing head.

The casing head and the body I09 may be provided on their upper surfaces with sealing ring grooves H and III in the same manner as shown in Fig. 1 and the body I09 may be provided with an upstanding neck portion H terminating in a welding bevel I I6. This neck portion may likewise be provided with a plugged tapped opening II"! for the same purpose as the opening I! in Fig. 1.

As in the form shown in Fig. 1, the casing head is preferably provided with a passage II 2 terminating in a threaded opening H3 in which may be inserted a plug II 4, all these being for the purpose of the injection of a testing fluid under pressure in the manner hereinafter set forth.

As in the case of the annular member 9, the annular member I09 is provided with four grooves, two in its inner surface as indicated by the numerals H8 and H9, and two in its outer surface indicated by the numerals I20 and MI. The inner grooves are illustrated as having disposed therein sealing rings I22 and I23 respectively, but the outer grooves are not shown as having any sealing rings therein, it being contemplated that since these grooves open into a threaded joint, the fiowable plastic material will resist extrusion sufficiently without the necessity for the sealing rings such as employed in Fig. 1.

Referring to Fig. 4, it will be seen that in this form the flowable material under pressure will be injected through registering openings in the flange of the casin head and in the annular member I09. In this instance, the casing head is provided with a tapped opening I 21 adapted to receive a threaded ram or plug I29 which may be removed to insert the material to be used in forcing the sealing rings I22 and I23 into sealing position, and then replaced and tightened to force such material past the ball valve I31 and into the passages within the annular member I09. The outer end of the threaded opening I21 may if desired be closed by means of a suitable plug I38.

The pressures within the passages in the an nular member I09 may be indicated by means of pressure indicators such as that illustrated in Fig. 3 and heretofore described or by similar indicators such as shown in Fig. 4 which are in substance identical with those shown in Fig. 3 except that they are made of shorter dimensions so that they may indicate pressures substantially at the level of the upper sealing rings instead of at the level of the lower rings. Otherwise. they are substantially the same in structure and function. It is to be noted that in the case of the pressure indicator shown in Fig. 4 just as in the case of that shown in Fig. 3, the parts are so propor- I09, corresponding to r an apparatus has been shown and described which is fully capable of carrying out and accomplishing all of the objects and advantages sought by this invention.

Having described my invention, I claim:

1. In a seal assembly for sealing off an annular "space, an annular body having a pair of annular grooves in its inner and in its outer surfaces. flexible sealing rings in said grooves respectively, said grooves being all interconnected, and means for supplying a nowable material under pressure to said grooves behind said rings.

2. in a seal assembly lor sealing 011 an annular space, an annular bony having an annular groove in its inner suriace, a IlEXlble sealing ring in said groove, means Ior forcing a viscous Iiowable material under pressure into said groove behind said ring, and pressure indicators at spaced points about said body and connected with said groove for indicating the pressures existing in such nowable material at points in said groove ad acent to such indicators respectively.

3. In a seal assembly lor sealing off an annular space, an annular body having a pair of annular grooves in its inner suriace and a pair of an nular grooves in its outer surlace, said grooves being all inter-connected, and means for supplying a .fiowable sealing material under pressure to the interiors of said grooves.

41. In a seal assembly for sealing oif an annular space, an annular body having a pair of annular grooves in its inner surface and a pair of annular grooves in its outer suriace, a pair of flexible sealing rings in said grooves in the inner surface respectively, all of said grooves being inter-connected, and means lor supplying a nowable sealing material under pressure to said grooves.

5. In combination with a well head, a seal assembly for sealing off an annular space within the well head comprising an annular body having a pair of annular grooves in its inner and in its outer surfaces, a pair of flexible sealing rings in the grooves in said inner surface respectively, all of said grooves being inter-connected, and means for supplying a riowable material under pressure to all of said grooves, said body and said well head having radial passages interconnecting the exterior of said well head with the inner and outer surfaces of said body between said grooves whereby a test fluid under pressure may be applied from the exterior of said well head simultaneously to the zones between the seal rings on the inner surface and between the grooves on the outer surface of said body, said body being threaded into the interior of said well head.

HERBERT ALIEN.

REFERENCES CITED The following references are of record in the tioned that the plunger will be substantiall flush with the outer contour of the ring I09 when the pressure within this ring is at the desired predetermined value.

From the foregoing it will be apparent that file of this patent:

UNITED STATES PATENTS Number Name Date 872,358 Liddell Dec. 3, 1907 1,047,719 Tyler Dec. 17, 1912 1,151,136 Taylor et al Aug. 24, 1915 1,872,498 Rasmussen et a1. Aug. 16, 1932 2,011,264 Wagner Aug. 13, 1.935 2,313,169 Penick et al. Mar. 9, 1:943 2,357,411 Leman et ai. Sept. 5, 1944

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