US3066823A

US3066823A - Sealing constructions

Info

Publication number: US3066823A
Application number: US855760A
Authority: US
Inventors: Mellon National Bank And Tr Co
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1959-11-27
Filing date: 1959-11-27
Publication date: 1962-12-04
Anticipated expiration: 1979-12-04
Also published as: CH393853A

Description

2 Sheets-Sheet 1 Filed NOV. 27, 1959 Dec. 4, 1962 B. P. BAKER SEALING CONSTRUCTIONS 2 Sheets-Sheet 2 Filed NOV. 27, 1959 \iW/ 36 mm E & a

Fig. 3.

Q SW

United States Patent Ofice Patented Dec. 4, 1962 3,066,823 SEALING CONSTRUCTIGNS Benjamin P. Baker, deceased, late of Monroeville, Pa.,

by Mellon National Bank and Trust Co., executor,

assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Nov. 27, 1955 Ser. No. 855,760 2 Claims. (Cl. 220-46) This invention relates to sealing constructions in general, and, more particularly, to scaling constructions for insuring the containment of a fluid within an enclosing vessel.

A general object of the present invention is to provide an improved sealing construction for containers containing 21 fluid. The term fluid as employed herein includes gases, liquids, vapors and sprays.

The present invention has particular applicability in the case of large devices, such as sulfur-hexafluoride sealed power circuit breakers of the type set forth and claimed in United States patent application, filed January 23, 1959, Serial No. 788,668, by Russel N. Yeckley, Joseph Sucha and Benjamin P. Baker, and assigned to the assignee of the instant application. In the aforesaid patent application there is illustrated and described a power circuit interrupter of considerable rating, namely, 15,000 mva., and employing pressure vessels containing sulfur-hexafluoride gas under pressure, say 60 p.s.i.

It is an object of the present invention to provide an improved sealing arrangement for pressure vessels of the type described in the aforesaid application.

Another object of the present invention is to provide improved means for detecting leaks at the gaskets employed in sealing constructions for containers containing a fluid.

Another object of the present invention is to provide an improved sealing construction involving a pair of spaced concentric annular gaskets, the space between which may communicate with a detecting bore, which is adaptable for receiving the detecting end of a leak detector.

Still a further object of the present invention is to provide an improved sealing construction involving a pair of concentric gaskets, the space between which communicates with a detecting bore, in which provision is made for injecting, under pressure, a semi-plastic caulking compound into the annular space between said annular gaskets for assisting in preventing leaks at the seal.

Further objects and advantages will readily become apparent upon reading the following specification taken in conjunction with the drawings, in which:

FIG. 1 is a perspective view of a three-pole power circuit interrupter of the type employing pressure vessels, which contain a sealed gas under pressure; FIG. 2 is a considerably enlarged, vertical sectional view taken through the upwardly extending terminal-bushing supportof FIG. 1, illustrating the improved sealing construction of the present invention; and,

FIG. 3 is an enlarged sectional view taken through the rotatable operating shaft-seal for the circuit interrupter of FIG. 1, showing an application of the present invention to the shaft-seal.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 1 generally designates a high-voltage, high-power, fluid-blast circuit interrupter, adaptable for the control of a three-phase transmission circuit, whose lines are indicated by the reference numerals L L L L L L As noted in FIG. 1, there is provided an elongated tank structure 2 for each poleunit of the circuit interrupter 1. The pole-units may generally be designated by the letters A, B and C. The poleunits are identical in construction; consequently, a description of the operation of one pole-unit, for instance, pole unit A, will suflice for an understanding of the operation of pole-units B and C, which are identical. As illustrated in FIG. 1, a weatherproof enclosing tube 3 encloses an axially movable operating rod, which mechanically interconnects the three pole-units A, B and C for simultaneous operation, so that there is no relaying difficulty. An accelerating spring housing 3a is disposed at the end of the stationary weatherproof tube 3, within which is disposed an opening accelerating spring, not shown, which biases the enclosed operating rod axially to the right, as viewed in FIG. 1.

A mechanism and gas-control housing 4 is disposed adjacent to the tank structure 2 of front pole-unit A, and not only houses a rather conventional pneumatic mechanism for effecting the axial motion of the enclosed operating shaft within tube 3, but also the housing 4 encloses the equipment for maintaining the dual-pressure, gas-supply system at the desired pressures.

Each of the tank structures 2 includes a generally horizontally extending cylindrical tank portion 5, which has a pair of hinged closure caps 6 at its opposite ends. The hinged closure caps, or heads 6, may be swung to an open position about their hinges, to permit the lateral Withdrawal of an arc-extinguishing assemblage, not shown, from the tank structure 2 during maintenance operations.

Reference may be had to the aforesaid patent application for a detailed description of the manner of operation of the arc-extinguishing assemblage, which is positioned within each of the three tank structures 2, and is supported at the lower ends of the terminal bushings 12, 13, which extend downwardly through cylindrical bushing supports 11, the latter being welded to the upper sides of the tank structures 2.

The present invention is, in part, particularly concerned with sealing constructions for providing a sealed mounting connection between each of the terminal bushings 12, 13 and the upper end of the cylindrical terminalbushing support 11. In addition, the present invention is particularly concerned with a sealing construction for each of the end closure caps 6, which must be opened during service operations performed upon the interrupters.

The present invention is also concerned with a shaftsealing construction for transmitting power externally of the tank structure 2 interiorly thereinto.

-In the manufacture of sulfur-hexafluoride (SP circuit breakers, where the gas must be contained at pressures varying from 30 p.s.i.g. to 1,000 p.s.i.g., it is necessary to be able to detect very small leaks. This can be done by adding a very small trace of CCl, or Freon to the SP and then snifling with the halogen leak detector, or some other suitable means.

This is a rather slow operation and difficult to perform when not shielded from wind and weather. Some of these seals involve doors, such as the end caps 6, for the interrupter 1 of FIG. 1, 36 inches or more in diameter, which must be removed in the field for inspection and maintenance.

To overcome these difficulties, it is proposed to use two gaskets, or O-rings placed in separate grooves with the space between them communicating with the outside, such as shown in FIGS. 2 and 3 of the drawings. With such constructions, three very desirable eifects have been obt-ained.

First, the sniffing element of the leak detector, not shown, can be inserted into the opening 7 and any leaks past the inner ring, or gasket 9, regardless of its size, can be immediately detected. Such an operation is not affected by wind, weather or contaminating atmosphere.

If the inner gasket 9 shows a small leak, and it is not convenient to make repairs, detecting bore 17 can be sealed, employing a sealed plug 18, and the outer, second gasket 19 used as a back-stop.

A third advantage is that if both gaskets '9, 19 leak, and it is impractical to take the circuit interrupter 1 out of service immediately, some semi-plastic caulking compound, such as an elastomeric silicone compound, can be pumped into the space 20 between the inner and

outer gaskets

9, 19, respectively.

Elastomeric polyester may also be used. Polyurethane foam, which has the characteristics of expanding after it is pumped into position, could be used to seal small cracks between the inner and

outer gaskets

9, 19, and likewise pumped under pressure into the detecting bore 17 and into the space 20.

It will be noted that the sealing construction employed in the present invention is very simple in application. It is only necessary to provide a pair of sealing grooves 21 in a sealing member 22. This sealing member 22, as shown in FIG. 2, may constitute the upper flanged extremity of the terminal-bushing cylindrical support 11. Or, as shown in FIG. 3, the sealing member 22 may constitute a flanged mounting support 23, constituting a part of a shaft-mounting assembly 24, which is employed to provide a shaft-seal in transmitting power through the wall of a sealed tank 2.

The rotatable shaft 25 may have an internal lever 26 fixedly secured to the inner end of the shaft 25. Secured to the outer end of the rotatable shaft 25 is an external lever 27, which is employed to effect rotation of the shaft 25. One end of the shaft 25 may be rotatably guided by

roller bearings

28, 29, as shown in FIG. 3.

The inner end of the rotatable shaft 25 may have associated therewith a plurality of abutting polytetrafluoroethylene V-rings 30, which may be maintained under pressure by a washer 31 and a compression spring 32. One end of the compression spring 32 is advantageously maintained into position by an annular support cap 33, secured by bolts 34 to the flanged mounting support 23 of the shaft mounting assembly 24.

Fixe-dly securing the shaft-mounting assembly 24 into position through the wall 5 of the power circuit-interrupter tank 2 are bolts 36. With reference to FIG. 1, the longitudinally movable operating rod, disposed within the surrounding weatherproof tube 3, is employed to effect rotation of the external operating lever 27, and hence effect corresponding rotation of the internal operating lever 26. The rotation of the internal operating lever 26 is effective to open the contact structure and the blast valve associated with each of the arc-extinguishing assemblages, not shown, disposed longitudinally interiorly within each of the tank structures 2, and supported therein by the lower interior ends of the terminal bushings 12, 13, in a manner set forth in detail in the aforesaid patent applica tion.

With reference to FIG. 2, it will be noted that the grounded flangedsupport plate 37 of the terminal bushing 12 is suitably secured, as by a plurality of bolts 38 to the flange member, or sealing member 22, which is welded, as at 39, to the upper extremity of the cylindrical bushing support'll. Thus, the lower surface 40 of the flange plate 37 makes abutting engagement with the O-

rings

9, 19 for a fluid-tight engagement. Similarly, the mounting support 41 (FIG. 3), which is welded, as at 42, to the cylindrical wall 5 of the tank structure 2, makes abutting contact with the first and second gasket means, 9-, 19, respectively, associated with the shaft-mounting assembly 24; As before, the resilient first and second gasket means 9, 19 are mounted inconcentric grooves-21 provided in the flanged mounting support 23.

It will be obvious, from the foregoing description of the invention, that either the end flange 43 (FIG. 1) welded to the end of the cylindrical section 5, or the flange portion 44 of the end closure cap 6 may be provided with spaced concentric sealing grooves 21, as in FIGS. 2. and 3,

l and may have associated therewith similar ring-shaped

annular gaskets

9, 19.

'From the foregoing description, it will be apparent that there is illustrated and described an improved sealing construction, which may be either asociated with a shaftseal or with static closure members associated with a fluid-tight container containing any suitable fluid, which it is desired to retain in a sealed manner. Such a sealing construction may be employed in connection with each of the pole-units A, B, C illustrated in FIG. 1, it being noted that in the case of each pole-unit there are employed five sealing locations. This is apparent when it is realized that there are two end caps 6, each of which has a sealing construction of the type set forth in FIGS. 2 and 3 associated therewith. In addition, each pole-unit has two upwardly extending cylindrical bushing supports 11, each of which has a sealing construction, such as illustrated in FIG. 2 of the drawings. Moreover, the longitudinally movable shaft, disposed within enclosing tube 3, has to be connected to the external lever 27 and have power therefrom transmitted through the wall 5 of the tank structure 2. This shaft-seal is of the type set forth in FIG. 3 of the drawings. As a result, there are fifteen sealing locations associated with the entire threepole power circuit interrupter illustrated in FIG. 1. Since the gas, such as sulfur-hexafiuoride gas, is retained under pressure within each of the sealed tank structures 2, it is readily apparent that a highly effective seal is desirable, which, in addition, it is desired to associate with the possible use of a leak-detector device.

By removing the pipe plug 18, associated with the detecting passage 17, and inserting the detecting end of a leak detector into the opening 7, as mentioned, the accumulation of gas within the detecting passage 17 may readily be detected without hindrance from the atmospheric elements.

There are many choices of sealing caulking compounds available for use in injecting them under pressure within the detecting passage 17, and into the space 20 between the first and second gasket means, 9, 19, respectively. The above examples were given only by way of illustration. Others will be readily apparent to those skilled in the art.

Although there have been illustrated and described various types of sealing constructions, it is to be clearly understood that the same were merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the invention.

Accordingly, what is claimed as new is:

1. In a sealing construction between two sealing members having substantially fiat abutting surfaces, one of said members being generally annular and having passage means therethrough containing fluid which it is desired to seal, a pair of spaced annular concentric gasket grooves in the contacting surface of one of said sealing members, the other sealing member being flat at the point of contact, an annular resilient gasket disposed in each of said gasket grooves, the depth of the two gasket grooves being less than the uncompressed thickness of the gaskets, the outer of the two gasket grooves having a width which is greater than the width of the resilient gasket disposed therein when compressed to define an annular sealing passage whereby the annular sealing passage may serve as a reception space for a sealing fluid, means defining a detecting passage communicating at one end with said annular sealing passage and at the other end with a point external to said one sealing member, and a single removable closure means for closing the external end of said detecting passage.

2. In a sealing construction between two sealing members having substantially flat abutting surfaces, one of said members being generally annular and having passage means therethrough containing fluid which it is desired to seal, a pair of spaced annular concentric gasket grooves in the contacting surface of one of said sealing members, the other sealing member being flat at the point of contact, an annular resilient gasket disposed in each of said gasket grooves, the depth of the two gasket grooves being less than the uncompressed thickness of the gaskets, the outer of the two gasket grooves having a width which is greater than the width of the resilient gasket disposed therein when compressed to define an annular sealing passage whereby the annular sealing passage may serve as a reception space for a sealing fluid, means defining a detecting passage communicating at one end with said annular sealing passage and at the other end with a point external to said one sealing member, a semi-plastic sealing compound forced through said detecting passage and into said annular sealing passage, and a single removable closure means for closing the external end of said detecting passage.

References Cited in the file of this patent UNITED STATES PATENTS 2,208,778 Stuart July 23, 1940 2,460,054 Wiggins Jan. 25, 1949 2,492,409 Worn et a1. Dec. 27, 1949 2,510,417 Rehklau June 6, 1950 2,590,803 Unger et al Mar, 25, 1952 2,727,286 Moore Dec. 20, 1955 2,750,069 Gross June 12, 1956 2,760,673 Laurent Aug. 28, 1956 2,840,262 Learmonth et al June 24, 1958 2,921,608 Crawford et a1 Ian. 19, 1960