US3349793A

US3349793A - Evacuator assembly

Info

Publication number: US3349793A
Authority: US
Inventors: Balch William
Original assignee: QUINT MACHINE CORP
Current assignee: QUINT MACHINE CORP
Priority date: 1964-10-15
Filing date: 1964-10-15
Publication date: 1967-10-31
Anticipated expiration: 1984-10-31

Description

w. BALCH w .L mA TB N M WA WU Lu W EVACUATOR ASSEMBLY Filed 0G13. l5, 1964 Oct. 31, 1967 ATTORNEY United States Patent O Quint Conn., a corpora- This invention relates to an evacuator assembly and, more particularly, to a device especially useful in evacuating a space or container which performs an insulating function by thermally isolating a cryogenic line from its surrounding medium.

In the application of cryogenic techniques, pipes and lines are often used to carry liquid nitrogen or liquid hydrogen for instance, at extremely low temperatures of the order of approximately 250 C. below zero. In order to increase eiciency and minimize losses in a cryogenic system, all or part of the connecting lines in such a system may be enclosed within a chamber which is evacuated to provide an insulating medium in the form of a thermally non-conductive space within the chamber and surrounding the cryogenic system elements. The present invention is particularly useful and desirable in its application of effecting and maintaining the evacuation of such a vacuum chamber surrounding a cryogenic line or portions of a cryogenic system.

Accordingly, it is an object of the present invention to provide means for effectively evacuating a space or container, which vacuum provides an insulating medium around a pressurized pipe, line, or element enclosed within the container.

Another object of the present invention is to seal the exhaust port ofsuch an evacuated container or chamber with a means thereafter held in sealing relationship by the pressure outside the evacuated chamber.

Yet another object of the present invention is to provide a safety feature for the fail-safe relief of pressure should a leak develop in the cryogenic line or other pressurized element within the evacuated chamber.

A further object of the present invention is to provide a protective cover to prevent accidental unseating of the sealed port of the vacuum chamber after evacuation and also to permit free flow of relief pressure through the protective cover, if such should be necessary.

These and other features and advantages of the present ,invention will be more fully appreciated from a reading of the specitication which follows, when taken together with the drawings wherein:

FIGURE 1 is a side elevation, partially cross-sectional View of an evacuator assembly of the present invention.

FIGURE 2 is a top View of the protective cover employed as conceived by the present invention, and

FIGURE 3 is a cross-sectional view of the protective cover of FIGURE 2 taken through section 3-3.

The concept of the present invention includes the steps of connecting an exhaust conduit to the chamber which is'to be evacuated, evacuating both the chamber and exhaust conduit, then positioning a sealing disc in mechanical pressure engagement over the exhaust port, admitting air or similar gas to the exhaust conduit and removing the exhaust conduit assembly from connection with the exhaust port whereupon the sealing disc remains positioned over theexhaust port and held in sealing engagement by reason of the greater outside pressure as contrasted to the highly evacuated space on the inside of the container. Finally, a protective cover is placed over the sealing disc to prevent its accidental dislodgement and loss of the vacuum within. The cover may be secured to the exhaust port of the evacuating chamber by a suitable means such as a piece of wire threaded through holes in the outer wall of the exhaust port which are aligned with matching ICC holes in the protective cover. Such a wire arranged in this manner will secure the protective cover in place but yet allow the cover and sealing disc to be unseated should extraordinary pressures be built up within the evacuating chamber.

The operative members of the assembly of the present invention include an exhaust conduit which is adapted to be removably sealed over the exhaust port of the chamber to be evacuated, a sealing disc fitted to seal the exhaust port and means detachably connected to the sealing disc and adjustably supported within theV exhaust conduit for positioning and seating the disc under mechanical pressure on the exhaust port.

The manner in which the operation and concept of the present invention are applied and carry out its objectives will be better understood by referring to FIGURE 1 which shows an evacuation chamber generally at 10, an exhaust port for the chamber at 11, and an exhaust conduit 12. The exhaust conduit indicated generally at 12, may be connected to a suitable vacuum pump or other evacuating means at the outlet 22. A vacuum gauge 23 is operatively connected to respond to the vacuum Within the exhaust conduit and to continuously indicate the degree of vacuum in both the chamber to be evacuated 1d and the exhaust conduit 12. A purge valve 24 is connected with the exhaust conduit 12 to admit air at atmospheric pressure or other suitable gas such as dry nitrogen to lill the space within the exhaust conduit 12 in a manner which will be more fully explained hereinafter. The exhaust conduit 12 also includes a portion indicated generally at 13 which is of a size and configuration adaptable to be removably sealed over and about the exhaust port 11. In this particular embodiment of the present invention, an O-ring 14 of resiliently deformable material such as butyl or other suitable material is positioned within an annular recess 15 of the exhaust conduit 12 so as to slidingly engage the outside diameter of the exhaust port 11. A sealing disc 16, which has an O-ring 17 positioned under its sealing face, is shown in place over the exhaust port 11. It will be noted that the sealing disc 16 is threaded to a rod 18 so that the rod may be removed from engagement with the sealing disc 16 when desired by unscrewing the two elements. A clamp 19 is supported in the connecting portion 13 of the exhaust conduit 12 and the upper portion of the rod 18 passes through a clamp 19, an O-ring 2t) sealing the aperture by which the rod 18 passes through the connecting portion 13 and the exhaust conduit 12. A ball valve 21 or other suitable means is posi- ,tioned in the exhaust conduit 12 between its connecting portion 13 and its outlet 22 so that evacuating means connected to the outlet 22 may be operatively disconnected from the exhaust conduit 12 without loss of vacuum within the conduit.

The steps by which the concept of the present invention are carried out through the use of apparatus as shown in FIGURE 1 are as follows: The connecting portion 13 of exhaust conduit 12 is placed over the exhaust port 11 with the O-ring 14 engaging the outer diameter of exhaust port 11 to form a seal between the exhaust conduit 12 and the exhaust port 11. The rod 18, screwed into engagement with the sealing disc 16, is lifted to raise the sealing disc 16 from engagement with the exhaust port 11. Suitable evacuating means, connected to the exhaust port 12 through its outlet 22, is actuated and the chamber to be evacuated 10 is exhausted to the desired degree as indicated by the vacuum gauge 23. The rod 18, together with the sealing disc 16, is lowered to position the sealing disc 16 over the exhaust port 11, sealing the opening. The sealing disc 16 and its O-ring 17 are placed in mechanical pressure over the opening of the exhaust port 11, the rod 18 and the sealing disc 16 being held under mechanical pressure by the clamp 19. The

valve 21 is closed and air, dry nitrogen, or other suitable gas is then admitted to the exhaust conduit 12 through the purge valve 24, and the changing pressure within the exhaust conduit 12 is indicated by the vacuum gauge 23. The pressure within the exhaust conduit 12 is allowed to reach a sufficient level so that the sealing disc 16 will be held in pressure-tight contact with the exhaust port 11 without the aid of the mechanical pressure applied through the clamped rod 18.

The clamp 19 is then loosened, rod 18 is unscrewed from the sealing disc 16 and the exhaust conduit 12 removed from connection with the exhaust port 11 of the evacuated chamber 10.

A protective cover 25 shown somewhat enlarged in FIGURES 2 and 3 having an inside diameter slightly larger than the outside diameter of the exhaust port 11, is then placed over both the exhaust port 11 and the sealing disc 16 which is seated thereon. The holes 26 drilled through the protective cover 25 are positioned to align with the holes 26a drilled laterally through the outside wall of the exhaust port 11. A piece of wire may then be passed through both sets of holes 26 and 26a in a generally U-shaped fashion to secure the protective cover 25 against accidental dislodgement. With or without such a securing wire the protective cover 25, of course, has the function of preventing the accidental displacement of the sealing disc 16 from the exhaust port 11 and consequent loss of vacuum within the evacuated chamber 10. Additionally, the protective cover 25 has a plurality of holes 27 drilled in its top and side which have a particular function within the concept and objects of the present invention. The holes 27 are so dimensioned as to have an aggregate total area which is at least equal to the area of the exhaust port 11 connecting the evacuated chamber with its outside. Thus, in the event that an element such as a cryogenic line contained within the evacuated chamber 10 should develop a leak and permit liquid nitrogen, for instance, to escape and expand within the evacuated chamber, the sealing disc 16 would be unseated from its sealing position as the pressure within the evacuated chamber 10 became equal to or greater than the outside atmospheric or surrounding pressure. When the sealing disc 16 is seated and held over the exhaust port 11 by the outside pressure, it performs not only its sealing function but is also in effect a fail-safe relief valve requiring no adjustment whatever. The protective cover 25, having a plurality of holes or apertures 27 of an aggregate area equal to the area of the exhaust port 11, will allow the pressure to escape without sudden dislodgement of the protective cover and possible resulting injury or damage, since the gas under pressure will seek and nd the same aggregate area of outlet in the protective cover 22 as is present in the exhaust port 11.

Those skilled in the art will recognize that sealing elernents other than O-rings of butyl rubber `may be used and where necessary or desirable a vacuum grease or other suitable sealing medium may be employed in the practice of the present invention.

The concept of the present invention has the advantages of being simple and effective to provide a convenient means of evacuating a chamber while affording a number of safety features. For example, the sealing disc which is designed and conceived to be positioned in a sealing relationship over the exhaust port is held in such sealing position entirely by the atmospheric or surrounding outside pressure after the exhaust conduit has performed its function of evacuating the chamber and has been removed from connection with the chamber. This arrangement prevents the accidental and unintentional build up of undesired pressures within the evacuated chamber. The sealing disc effectively performs the function of a failsafe relief valve in that it will automatically be unseated upon the build up of such pressures, relieving the pressures and preventing damage to the equipment or injury to personnel.

The protective cover of the present invention insures that the sealing disc, while being held under atmospheric pressure or the outside pressure surrounding the evacuated vessel, will not be accidentally dislodged and thereby lose the vacuum within the evacuated chamber which may provide the desired thermal insulation for a cryogenic line or element, for instance. Further, the operative features of the protective cover co-acting with the other elements of the present invention are such that it will not only perform its function of preventing accidental dislodgement of the sealing disc but is also designed to avoid sudden and dangerous dislodgement of the protective cover itself as a result of a rapid build up of pressure within the evacuated vessel.

Since many changes could be made in the above construction and many apparently widely different embodiments of the invention could be made without departing from the scope or spirit thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described the invention, I claim:

1. An evacuator assembly for sealing the exhaust port of a chamber comprising an exhaust conduit having one end adapted to be removably seated around the exhaust port and an exhaust outlet connection at the other end thereof; first deformable sealing means adjacent said one end of said exhaust conduit for sealing between the exhaust conduit and the exhaust port received therein; a disc movable within said exhaust conduit adjacent said one end thereof and dimensioned to seat on the exhaust port within said exhaust conduit; disc operating means detachably connected to said disc and adjustably supported in said exhaust conduit, said operating means being extensible in alignment with the exhaust port to seat said disc thereon; second deformable sealing means on the face of said disc opposite said operating means to seal against the face of the exhaust port cooperating therewith; valve means to selectively shut off said exhaust outlet connection from said exhaust conduit; and a valved connection between said valve means and said disc for admitting a gas under pressure into said exhaust conduit to apply pressure to the face of said disc adjacent said operating means whereby, -upon evacuation of the chamber through the exhaust port, the disc may be moved into sealing engagement with the exhaust port by said operating means and pressure applied thereto through said valved conduit to maintain said disc in engagement therewith and thereafter said operating means may be disengaged from said disc and the evacuator assembly removed `from the exhaust port.

2. The evacuator assembly of claim 1 wherein said exhaust conduit includes pressure responsive indicating means.

3. The evacuator assembly of claim 1 wherein said first and second sealing means are O-rings of resiliently deformable material disengageably seated in cooperating annular recesses in said conduit and disc respectively.

4. The evacuator assembly of claim 1 wherein there is included clamp means outwardly of said exhaust conduit slidably adjustable on said disc operating means to position said disc within said conduit.

5. In the method of evacuating and sealing the exhaust port of a vacuum chamber, the steps comprising: connecting an exhaust conduit from an exhausting means to said exhaust port, evacuating said chamber and said exhaust conduit, positioning a sealing disc over said exhaust port, closing said exhausting means from said conduit, admitting gas to said exhaust conduit downstream `of said disc to apply pressure to said sealing disc to maintain it in sealing engagement with said exhaust port, and thereafter removing said exhaust conduit from connection with said exhaust port and with said `disc remaining in sealing engagement therewith through atmospheric pressure applied thereon.

6. The method of claim 5 wherein said exhaust port References Cited UNITED STATES PATENTS Darling et al. 220-39 Abramovitz 137-319 Wolf 137-317 X Donovan et al 141-66 6 3/.1949 Petry 141-( 10/ 1952 May 62-299 9/ 1956 Sieling 251-148 4/1959 Johnson 137-32 2/1962 Ipsen et al. 137---34 7/ 1965 Wiersholm 137-37 FOREIGN PATENTS 5/ 1928 France.

10 M. CARY NELSON, Primary Examiner. HENRY T. KLINKSIEK, Examiniem

Claims

1. AN EVACUATOR ASSEMBLY FOR SEALING THE EXHAUST PORT OF A CHAMBER COMPRISING AN EXHAUST CONDUIT HAVING ONE END ADAPTED TO BE REMOVABLY SEATED AROUND THE EXHAUST PORT AND AN EXHAUST OUTLET CONNECTION AT THE OTHER END THEREOF; FIRST DEFORMABLE SEALING MEANS ADJACENT SAID ONE END OF SAID EXHAUST CONDUIT FOR SEALING BETWEEN THE EXHAUST CONDUIT AND THE EXHAUST PORT RECEIVED THEREIN; A DISC MOVABLE WITHIN SAID EXHAUST CONDUIT ADJACENT SAID ONE END THEREOF AND DIMENSIONED TO SEAT ON THE EXHAUST PORT WITHIN SAID EXHAUST CONDUIT; DISC OPERATING MEANS DETACHABLY CONNECTED TO SAID DISC AND ADJUSTABLY SUPPORTED IN SAID EXHAUST CONDUIT, SAID OPERATING MEANS BEING EXTENSIBLE IN ALIGNMENT WITH THE EXHAUST PORT TO SEAT SAID DISC THEREON; SECOND DEFORMABLE SEALING MEANS ON THE FACE OF SAID DISC OPPOSITE SAID OPERATING MEANS TO SEAL AGAINST THE FACE OF THE EXHAUST PORT COOPERATING THEREWITH; VALVE MEANS TO SELECTIVELY SHUT OFF SAID EXHAUST OUTLET CONNECTION FROM SAID EXHAUST CONDUIT; AND A VALVED CONNECTION BETWEEN SAID VALVE MEANS AND SAID DISC FOR ADMITTING A GAS UNDER PRESSURE INTO SAID EXHAUST CONDUIT TO APPLY PRESSURE TO THE FACE OF SAID DISC ADJACENT SAID OPERATING MEANS WHEREBY, UPON EVACUATION OF THE CHAMBER THROUGH THE EXHAUST PORT, THE DISC MAY BE MOVED INTO SEALING ENGAGEMENT WITH THE EXHAUST PORT BY SAID OPERATING MEANS AND PRESSURE APPLIED THERETO THROUGH SAID VALVED CONDUIT TO MAINTAIN SAID DISC IN ENGAGEMENT THEREWITH AND THEREAFTER SAID OPERATING MEANS MAY BE DISENGAGED FROM SAID DISC AND THE EVACUATOR ASSEMBLY REMOVED FROM THE EXHAUST PORT.