US3357446A

US3357446A - Method and apparatus for evacuating sealed chambers

Info

Publication number: US3357446A
Authority: US
Inventors: Ira W Simons
Original assignee: CRYO VAC Inc
Current assignee: CVI Inc; CRYO VAC Inc
Priority date: 1966-12-29
Filing date: 1966-12-29
Publication date: 1967-12-12
Anticipated expiration: 1984-12-12

Description

Dec. 12, 1967 l. w. SIMONS A 3, 5 ,446

METHOD AND APPARATUS FOR EVACUATING SEALED CHAMBERS Filed Dec. 29, 1966 5 Sheets-Sheet l FIG.1

INVENTOR IRA W. SIMONS ATTORNEYS Dec. 12, 1967 w. SIMONS 3,357,446

METHOD AND APPARATUS FOR EVACUATING SEALED CHAMBERS Filed Dec. 29, 1966 5 Sheets-Sheet INVENTOR IRA w. SIMONS ATTORNEYS FIG.4

Dec. 12, 1967 w. SIMONS METHOD AND APPARATUS FOR EVACUATIN Filed Dec. 29, 1966 G SEALED CHAMBERS I 5 Sheets-Sheet 5 FIG.5

INVENTOR.

IRA W. SIMONS ATTORNEYS I. W. SIMONS METHOD AND APPARATUS FOR EVACUATING SEALED CHAMBERS Dec. 12, 1967 5 Sheets-Sheet 4 Filed Dec. 29, 1966 R m we V M mm 0 H W A m I l 6 H4 FIGS ATTORNEYS I. W. SIMONS Dec. 12, 1967 METHOD AND APPARATUS FOR EVACUATING SEALED CHAMBERS Filed Dec. 29, 1966 5 Sheets-Sheet 5 FIG. 10

INVENTOR.

IRA W. SIMONS UM Miami ATTORNEYS United States Patent 3,357,446 METHOD AND APPARATUS FOR EVACUATING SEALED CHAMBERS Ira W. Simons, Columbus, Ohio, assignor to Cryo-Vac,

Inc., Columbus, Ohio, a corporation of Ohio Filed Dec. 29, 1966, Ser. No. 605,904 11 Claims. (Cl. 137322) The present invention relates to method and apparatus for use in evacuating sealed chambers such as the evacuated insulating spaces provided around conduits or vessels for containing cryogenic gases such as liquid nitrogen and the like.

This application is a continuation-in-part of my c0- pending applications Ser. No. 402,300, Ser. No. 402,299, and Ser. No. 402,298, all filed on Oct. 7, 1964 and all now abandoned.

In general, the valve mechanism of the present invention comprises a fixed housing portion for parmanent attachment to the wall of the chamber to be evacuated and a valve means removably mounted in the fixed housing portion which provides means for releasing air from the sealed chamber to a pump apparatus.

The valve means includes a valve element that is normally biased closed against a valve seat and the only time it is open is when subjected to suction from a vacuum pump during the actual evacuation of the chamber. The valve element is also self-closing after evacuation to seal out air from the environment.

The valve means also includes a removable cover which is mountable on a shoulder of the fixed housing portion after evacuation of the chamber which cover includes a Warning device to provide visual detection of the leakage of cryogenic gas from the conduit or vessel through the evacuated chamber to the environment.

As another aspect of the present invention the same shoulder of the fixed housing portion upon which the valve cover is mounted can also be adapted to function as a mount for a pump attaching apparatus in the form of an outer removable housing when evacuation of the sealed chamber is desired. It will be understood that the valve cover is replaced by mounting it on the same shoulder when the pump attaching apparatus is removed after evacuation.

When the outer housing portion is afiixed to the inner housing portion for the evacuation period it provides a sealed chamber around the above mentioned valve assembly which sealed chamber forms a passage that connects the valve assembly and outlet port for the chamber with the vacuum pump.

In accordance with the present invention the above mentioned pump attaching means or outer housing portion includes a valve assembly lifting mechanism which provides means for the operator to lift the above mentioned valve assembly outwardly but within the sealed housing portion to an evacuating position wherein the valve assembly is not interposed in the flow of air between the outlet port of the sealed chamber and the inlet of the conduit leading to the vacuum pump.

The valve assembly may be locked in this evacuation position during actual evacuation by means of a positive locking device provided in the handle portion of the lifting mechanism.

It will now be understood that with the valve assembly moved to the outer no-restricting position the apparatus is adapted to effect What may be termed high conductance pumping, that is to say the valve components are actually removed from the air flow path while the sealed chamber is being evacuated. This results in highly efficient pumping of air at low pressure under which conditions the air molecules are particularly impeded in their 3,357,446 Patented Dec. 12, 1967 "ice flow by passage restrictions normally present in the form of valve components.

After evacuation of the chamber, the lifting mechanism is unlocked by the operator and used to return the valve assembly to its normal inner shut-off position wherein it prevents the ingress of environmental air to the evacuated chamber. Then the lifting mechanism may be removed completely.

It is, therefore, an object of the present invention to provide an novel valve apparatus for use in evacuating sealed chambers and is adapted for straight through high conductance pumping during the evacuation cycle wherein the valve assembly may be positively locked in the evacuation position.

It is another object of the present invention to provide a novel valve apparatus, for use in evacuating sealed chambers, having a handle portion which functions not only as a handle, but further as a positive locking means to hold the valve assembly in the evacuation position.

It is another object of the present invention to provide a valve mechanism for use in evacuating sealed chambers and is adapted to provide a visual warning for rapid detection of leakage of cryogenic gases through the valve means.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

FIG. 1 is a partial side elevational view, partially in section, showing an inner housing and valve means constructed in accordance with the present invention;

FIG. 2 is a top elevational view of the housing and valve means of FIG. 1;

FIG. 3 is a side sectional view of the housing and valve means of FIG. 1, the section being taken along the line 3 3 of FIG. 2;

FIG. 4 is a side elevational view, partially in section, of a cover and blow-out disk assembly comprising a portion of the valve apparatus of FIG. 1;

FIG. 5 is a side sectional view of a pump attaching means and valve means lift mechanism for use with the valve means of the preceding figures, the section being taken along the lines 5-5 of FIG. .6;

FIG. 6 is a top elevational view of the outer housing portion and valve means lift mechanism of FIG. 5;

FIG. 7 is a partial side view, partially in section, illustrating the pump attaching mechanism of FIGS. 5 and 6 in mounted relationship on the inner housing portion of FIGS. 14, the section being taken along the line 5-5 of FIG. 6;

FIGS. 8 and 9 are sectional views showing a lug and groove construction comprising a portion of the valve means lift mechanism of the present invention, the sections being taken along the line 8, 9-8, 9;

FIG. 10 is a side view, partially in section, showing the valve means of the preceding figures after it has been lifted by the valve means lift mechanism to a non-restricting evacuating position;

Referring in detail to the drawings, FIG. 1 through 4 illustrate a preferred embodiment of a valve apparatus for use in evacuating sealed chambers.

As an example, the valve apparatus indicated generally at 20 includes an inner housing portion 22 that is permanently secured to an outer wall or vacuum jacket 24 that forms an evacuated insulating space 26 around a conduit 28 which is used for conducting a flow of cryogenic gas such as liquid hydrogen, liquid nitrogen, or the like. It should be pointed out that inner housing portion 22 is extended through an opening 30 and securely '2 a mounted on jacket 24 at a scaled junction formed by a weld 32.

As seen in FIGS. 1 and 4, valve apparatus 20 further includes a removable cover 34 that comprises an annular inner wall surface 36 which is adapted to slip snuggl over an outer annular shoulder means 38 on inner housing portion 22, the latter being illustrated in FIG. 3.

Continuing to refer to FIGS. 3 and 4, an annular resilient seal 40 is mounted in an annular groove 42 in shoulder means 38 and the inner surface 36, FIG. 4, of valve cover 34 is provided with an annular groove 44 that receives resilient seal 40 when the cover is slipped down over inner housing portion 22.

Referring particularly to FIGS. 3, 7 and 10, it should next be explained that inner housing portion 22 supports a removable valve means indicated generally at 46 which means is joined to the inner housing portion at a threaded junction 48.

As best seen in FIG. 3, valve means 46 comprises an annular valve housing wall 50 in which is mounted a movable valve element 52 that is biased downwardly against a seat portion 54 formed on the upper end of the lower housing portion 22.

Movable valve element 52 is biased downwardly by a compression spring 56 interposed between the upper surface 58 of the valve element and a snap ring 60 removably disposed in a groove 62 formed in the inner surface of housing wall 50.

it should be pointed out that when valve means 46 is unscrewed and lifted away from lower housing portion 22 from the position of FIG. 7 to the position of FIG. 10, movable valve element 52 is retained within the valve housing wall 59 by the inwardly extending annular projection 64 which underlies an outwardly extending projection 66 on valve element 52.

Reference is next made to FIGS. through which illustrate a vacuum pump connecting means and valve means lift apparatus indicated generally at 7 0.

At the outset it should be mentioned that the apparatus 70 is mounted on inner housing portion 22, as seen in FIGS. 7 and 10, only while insulating space 26, FIG. 1, is being evacuated by a vacuum pump. After the evacuation cycle, apparatus 70, FIGS. 5, 7, and 10, is removed from the inner housing portion and cover 34 of FIGS. 1 and 4 is replaced over the valve means. The same pump attaching means is then attached to other valve assemblies for use in evacuating other chambers.

Referring particularly to FIGS. 5 through 7, the pump connecting means includes an outer housing portion 72 provided with an inner annular mounting surface 74 adapted to slip snuggly over shoulder means 38 and resilient seal 40 on the previously described inner housing portion 22.

Referring next to FIGS. 5 through 10 pump attaching means 70 includes an outlet conduit 76 that communicates with the inlet of a vacuum pump, not illustrated, and an inner sealed chamber 78 that forms an outer passage portion that communicates with an inner passage portion through inner housing portion 22, FIG. 3.

In general, it should now be explained that with the pump attaching means 70 in place on inner housing portion 22, as seen in FIG. 7, when the vacuum pump is operated air from within the insulating space 26, FIG. 1, is drawn through inner passage portion 8%, FIG. 3, and the annular space around movable valve element 52 when the latter is raised from its seat 54 by the suction of the pump. The air then passes through valve housing outlet ports 82, FIG. 7, and thence outwardly through conduit 76 to the vacuum pump.

When valve means 46 is lifted to the outer non-restricting position of FIG. 10 then air is exhausted from insulating space 26, PEG. 1, via the inner passage portion 80 of inner housing portion 22, FIG. 3, thence, directly through outer passage portion 78 of outer housing portion 72 and exhaust conduit 76 to the vacuum pump without passing through the relatively restricted path formed by the lifted and open movable valve element 52 and the relatively restricted outlet ports 82.

The apparatus for lifting valve means 46 from the seated shut-off position of FIG. 7 to the lifted non-restricting position of FIG. 10 will next be described in detail. Such lift mechanism comprises a lift rod 86 slideably extended through a bore 88 through the top of outer casing 72 and also through sealing

elements

90 and 92 and a seal retaining and compressing nut 94.

The lower end of lift rod 86 includes a first latching meansin the form of a latch member 96 secured against rotation on the lower end of rod 86 by a pin 98 extended through a hole 100 in the end of the rod and the holes 102 in the latch member 96. The first latching means in the form of latch element 96, just described, is adapted to detachably engage a second latching means formed by two arcuate grooves 104, FIGS. 3, 8, and 9, formed in the upper inner surface of valve housing 50.

With continued reference to FIGS. 5, 8, and 9, the latch member 96 on the lower end of lift rod 86 includes radially outwardly extending projections 106 that can be inserted into the open ends 108 of arcuate slots 104 by lowering lift rod 86 when rotated to the position of FIG. 8 wherein projections 106 can move downwardly into slots 110.

With the projections 106 in slots 110, and in confronting relationship with the open ends 108 of arcuate grooves 104, a handle 112 on the upper end of lift rod 86 is rotated in a clockwise direction as indicated by the arrow in FIG. 8 to thereby rotate latch element 96 to a position wherein projections 106 engage the closed ends 114 of the arcuate grooves 104.

With the two latching mechanisms engaged as shown in FIG. 9 rotation of handle 112 Serves to unscrew valve assembly 46 from inner housing portion 22 at the previously mentioned threaded junction 48.

When the threads are disengaged the operator lifts rod 86 and valve assembly 46 from the normal shut-off position of FIG. 7 to the non-restricting evacuating position of FIG. 10, the vacuum pump is then started whereby the air is exhausted from insulating space 26 in the manner previously described.

It should be pointed out that while valve apparatus 46 is in the non-restricting position during the evacuation period handle 112 is pivoted about a central pivot pin 113, in the direction of arrow in FIG. 10, to cause a groove 122, FIG. 5, in the bottom of handle 112 to align with rod 86. It will be understood that the right end 124 of handle 112 will then overlie packing retaining nut 94 and prevent lift rod 86 and valve means 46 from moving into the lower position where it would restrict flow through outer housing passage portion 78.

After the insulating space 26 of FIG. 1 has been evacuated handle 112 is manipulated to lower valve means 46 back into mounted engagement with housing portion 22 at threaded junction .48 and the handle is then rotated to screw valve means 46 back into mounted engagement with outer housing portion 22 as seen in FIG. 3.

Rod 86 is next lifted to remove projections 106 out of slots 110 and pump connecting means 70 is next removed from its seat on shoulder means 38 of the inner housing portion.

Cover 34, FIG. 4, is next replaced on shoulder means 38 with the annular resilient seal 40 on housing portion 22 disposed in annular groove 44 in the cover.

With particular reference to FIG. 4, the top of cover 34 is provided with a blow-out disk which may be formed of mylar plastic sheet having a ten thousandths of an inch thickness or other suitable material. Disk 130 is mounted between an inturned flange 132 and a snap ring 134 mounted in a groove 136 formed in the inner surface of a side wall 138 of cover 34.

The purpose of blow-out disk 130 is to provide a visual indicator in the event there is leakage from liquified gas conduit'28, FIG. 1, into insulating space 26. If this occurs there is a rapid build up in pressure in insulating space 26, due to heating of the cryogenic gas with a resulting rapid build up in preessure which will blow movable valve element 52 off its seat and blow-out disk 130 outwardly from its mounted position on cover 34. With disk 130 blown out, an inspector could readily visually determine that leakage has occured in the system.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follows.

1. A mechanism for use in evacuating sealed chambers comprising, in combination, a housing portion attached to i a wall of said sealed chamber to be evacuated and including a passage communicating With the interior of said sealed chamber; valve means for said passage and removably mounted on said housing portion; a cover portion for said valve means and removably mounted to said housing portion; and valve means lift apparatus removably attachable to said housing portion and including interengaging means for connection with said valve means, said portion having sealing means for engagement with said cover and apparatus.

2. The steps in the method of evacuating sealed chambers which method comprises attaching a housing portion to the wall of a sealed chamber with a passage in said housing portion including a passage and a removable valve means for said passage; temporarily attaching a valve means lift apparatus to said housing portion, providing a seal on said housing portion in sealed relationship with said apparatus said lift apparatus including an outlet and interengaging means for connection with said valve means; attaching the inlet of a diffusion pump to said outlet; actuating said interengaging means to move said valve means and thereby clear a portion of said passage; operating said diffusion pump to evacuate said sealed chamber; and actuating said interengaging means to move said valve means to a closed position.

3. The steps in the method of evacuating sealed chambers which method comprises attaching a housing portion to the wall of a sealed chamber with a passage in said housing portion including a passage and a removable valve means for said passage; temporarily attaching a valve means lift apparatus to said housing portion, providing a seal on said housing portions in sealed relationship with said apparatus, said lift apparatus including an outlet and interengaging means for connection with said valve means; attaching the inlet of a diflusion pump to said outlet; actuating said interengaging means to move said valve means and thereby clear a portion of said passage; operating said diffusion pump to evacuate said sealed chamber; actuating said interengaging means to move said valve means to a closed position; and attaching a valve means cover to said housing portion.

4. A mechanism for use in evacuating sealed chambers comprising, in combination, a housing portion for attachment to a wall of a sealed chamber and including a passage communicating with the interior of said sealed chamber and a shoulder means; valve means for said passage and removably mounted on said housing portion; a valve cover removably attached to said shoulder means; and valve means lift apparatus removably attachable to said shoulder means and including interengaging means for connection with said vaive means.

5. A mechanism for use in evacuating sealed chambers comprising a housing portion for attachment to a wall of a sealed chamber, said housing portion including a passage communicating with the interior of said sealed chamber; valve means removably mounted in said housing portion; and means forming a mounting shoulder on said housing portion for removably sealably receiving a valve means lift apparatus that includes an outlet for sealed connection with a vacuum pump, whereby the passage portion communicates With said outlet.

6. An apparatus for. use in evacuating sealed chambers comprising, in combination, a fixed housing portion for permanent attachment to a wall of a sealed chamber and including an inner passage portion communicating with the interior of said sealed chamber; a valve assembly removably mounted on an outer end of said fixed housing portion and including a movable valve element, spring means biasing said valve element inwardly towards a valve seat, and a first latch means; a removable housing portion including an inner end mountable in sealed relationship on said fixed housing portion and having an inlet communicating with said inner passage portion and an outlet for connection with a vacuum pump; and a lift rod extended through a hole in the wall of said removable portion and including an inner rod end provided with a second latch means detachably engageable with said first means and an outer rod end provided with a handle portion having a position lock means for holding said lift rod in a fixed position. i

7. An apparatus for evacuating sealed chambers comprising in combination, a fixed housing portion for permanent attachment to a wall of a sealed chamber and including an inner passage portion communicating with the interior of said sealed chamber; a valve assembly removably mounted on an outer end of said fixed housing portion and including a movable valve element, spring means biasing said valve element inwardly towards a valve seat, and an inner wall surface provided with arcuate circumferentially extending grooves; a removable housing portion including an inner end mountable in sealed relation ship on said fixed housing portion and an outer passage portion having an inlet communicating with said inner passage and an outlet for connection with a vacuum pump; and a lift rod extended through a hole in the wall of said removable housing portion and including an inner rod end provided with radially extending projections detachably engageable with said arcuate grooves and an outer rod end provided with a handle portion having a position lock means for holding said lift rod in a fixed position.

8. An apparatus for use in evacuating sealed chambers comprising, in combination, a fixed housing portion for permanent attachment to a Wall of a sealed chamber and including an inner passage portion communicating with the interior of said sealed chamber; a valve assembly removably mounted on an outer end of said fixed housing portion and including a movable valve element, spring means biasing said valve element inwardly towards a valve seat, and a first latch means; a removable housing portion including an inner end mountable in sealed relationship on said fixed housing portion and having an inlet communicating with said inner passage portion and an outlet for connection with a vacuum pump; and a lift rod extended through a hole in the Wall of said removable portion and including an inner rod end provided with a second latch means detachably engageable with said first latch means and an outer rod end provided with a handle portion pivotable from a transverse position to an aligned position with said outer rod end for positive locking of said lift rod.

9. An apparatus for evacuating sealed chambers comprising in combination, a fixed housing portion for per manent attachment to a wall of a sealed chamber and including an inner passage portion communicating with the interior of said sealed chamber; a valve assembly removably mounted on an outer end of said fixed housing portion and including a movable valve element, spring means biasing said valve element inwardly towards a valve seat, and an inner wall surface provided with arcuate circumferentially extending grooves; a removable housing portion including an inner end mountable in sealed relationship on said fixed housing portion and an outer passage portion having an inlet communicating with said inner passage. portion and an outlet for connect with a vacuum pump; and a. lift rod extended through a hole in the wall of said removable portion and including an inner rod end provided with radially extending projections detachably engageable with said, arcuate grooves and an outer rod end provided with a handle portion pivotable from a. transverse position to an aligned position with said outer rod end for positive. locking of said lift rod.

10. An apparatus for evacuating sealed chambers comprising, in combination, a fixed housing portion for permanent attachment to a wall of. a, sealed chamber and including an inner passage portion communicating with the interior of said sealed chamber; a valve assembly removably mounted on an outer end of said fixed housing portion-v and including a movable valve element, spring means biasing said valve element inwardly towards a valve seat, and a first latch means; a removable housing portion including an inner end. mountable in. sealed relationship on said fixer housing portion and an outer passage portion having an. inlet communicating with said inner passage portion and an outlet for connection with a vacuum pump; and a lift rod extended through a hole in the wall of said removable housing portion and including an inner rod end provided with a second latch means detachably engageable with said first latch means and an outer rod end provided with a handle portion.

11. An apparatus for evacuating sealed chambers comprising, in combination, a fixed housing portion for permanent attachment to a wall of a sealed chamber and including an inner passage portion communicating with the interior of said sealed, chamber; a valve assembly removably mounted on an outer end of said fixed housing portion and including a movable valve element, spring means biasing said valve element inwardly towards a valve seat, and an inner wall surface provided with arcuate circumferentially extending grooves; a removable housing portion including an inner end mountable in sealed relationship on said fixed housing portion and an outer passage portion having an inlet communicating with said inner passage portion and an outlet for connection with a vacuum pump; and a lift rod extended through a hole in the wall of said removable housing portion, and including an inner rod end provided with radially extending projections detachably engageable with said arcuate grooves and an outer rod end provided with a handle portion.

References Cited I UNITED STATES PATENTS 1,422,342 7/1922 Darling et al. 220-39 1,483,964 2/1924 Abramovitz- 137-319 2,463,052 3/1949 Petry l4l.65 2,881,788 4/1959 Johnson l3732l 3,019,809 2/1962 Ipsen et al. l37-340 3,146,005 8/1964 Peyton 138l48 HENRY T. KLINKIEK, Primary Examiner.

Claims

1. A MECHANISM FOR USE IN EVACUATING SEALED CHAMBERS COMPRISING, IN COMBINATION, A HOUSING PORTION ATTACHED TO A WALL OF SAID SEALED CHAMBER TO BE EVACUATED AND INCLUDING A PASSAGE COMMUNICATING WITH THE INTERIOR OF SAID SEALED CHAMBER; VALVE MEANS FOR SAID PASSAGE AND REMOVABLY MOUNTED ON SAID HOUSING PORTION; A COVER PORTION FOR SAID VALVE MEANS AND REMOVABLY MOUNTED TO SAID HOUSING PORTION; AND VALVE MEANS LIFT APPARATUS REMOVABLY AT