US2032862A - Device for sealing-off metal tanks - Google Patents

Description

March 3, '@36., W. A, wiLKiNs DEVICE FOR SEALING-OFF METAL TANKS Filed July 29, 1952 Inventor: William Awilkins,

by Mx His Attorney.

Patented Mar. 3, 1936 y I, n l 2,032,862

DEVICE FOR SEALING-OFF METAL TANKS William A. Wilkins, Schenectady, N. Y., assignor to General Electric C New York ompany, a corporation oi' Application July 29, 1932,. Serial No. 626,053 i 2 claims. (c1. :ats-Q82)V The present invention relates to electric discharge apparatus and more particularly to devices for sealing evacuated envelopes which contain said apparatus.

devices, such as mercury-arc rectifier It is customary to use large metal tanks as envelopes for certain types of power-translating s, etc. and

these tanks are evacuated and sealed off from the pump.

the metal tank which is drawn down haust tube and sealed off when the evacuation.

This blown glass seal is process is complete.

In order to facilitate sealing, it is customary to provide a blown glass portion on to an exvery fragile and presents a structural weakness in an otherwise rugged apparatus.

entirely by a metal member.

In brief, my in- 'vention contemplates the use of a sealing device which is temporarily secured to the metal tank or container and which forces a copper or other metal plug into an exhaust opening in the tank when the evacuation is complete.

The invention will be better understood when reference is made to the following descriptionv and the accompanying drawing in which Fig. 1 shows a longitudinal section of the improved sealing device and Fig. 2 illustrates an elevational view of the device.

Numeral I designates a portion of a metal tank, the interior of which is to be evacuated.

An opening, preferably circular in form, is provided in the tank and to this opening, covering the same, there is secured, preferably by welding, a circular steel flange member 2 provided with a threaded upstanding projection 3 which contains an exhaust opening 4.

This opening is preferably chamfered as indicated at 5 on the interior of the tank and is slightly tapered, with the opening of smaller diameter nearer the tank.

The improved sealing device is constituted of a metal member 6, the exterior surface of which may be cut to a hexagonal shape in order to permit the application of a wrench for purposes as will appear hereinafter. a longitudinal opening consisting of The member 6 has two central bores of different diameter, the larger bore being of the same diameter as the opening in the flange member 3. The member 6 is provided at one end with an extension 1, threaded on the interior and adapted to be screwe threaded steel flange. tending transversely of the member 6 municating with the central bore.

d ontoy the There is an opening exand com- Into this opening is driven a'steel tubing 8, slightly chamfered at the inner end and tapering at the other end to make a close contact with a rubber hose (not shown) ,`aswill be explained presently. The upper end of the hexagonal member 6, as shown, 5 is turned downto form a seat 9 for a piece of extensible metal tubing I0 such as sylphon or the like, while'the interior of the metal member 6 at this end is chamfered, as indicated by reference character II. The member I0 at the top, 10 carries a metal cap I2 which is provided with a threaded bore' I3. This cap is fitted tightly to the'tubing I0 by means of a turned-down seat I4 and is chamfered on the interior as indicated by reference character I5. There is secured in 15 the threaded bore I3, a centrally disposed metal ram I6 which 'extends downwardly, as shown, through the bore of smaller diameter in the metal piece 6 and terminates slightly beyond the annular. shoulder formed between the two bores 20 of the member 6. The lower end of the ram I6 carries a. spring wire holder I1 in any convient manner, as for example by a hinge and over ythis holder there is forced a round sealing plug I8 of a relatively soft metal, such as chro- 25 lilium-plated copper. The plug is drilled at the surface which, contacts with the ram I6, the hole being of a size sufficiently small to permit the plug to be pressed tightly over the holder Il and to be securely attached thereto.

When it is desired to operate the device and the sealing plug I8 has been secured to the end of the ram, the sylphon tube I8 is stretched upwardly and held in that position until it is time to force the sealing plug into the opening of the 35 steel flange. In order to maintain the tubing in this position, there is provided a pair of metal arms I9 positioned on opposite sides of the metal member 6 and pivoted at their lower ends to this member about the screws 20. The upper 40 ends of these arms are cut ilat and horizontal, as shown, and are adapted to bear against or engage the lower surface of a circular flange provided on the cap member I2. The length of these arms I9 should be such as to hold the sylphon tubing in the extended position carrying with it, the ram I6 and the attached plug I8. It is apparent that when the device is in this position, the plug I8 is held away from the 50 opening 4 and the preferable arrangement is such that the plug I8, in its upper position, completely uncovers the opening in the horizontallyextending tube 8. The arms I9 are preferably connected together in any suitable manner, for 55 example, by an arcuate strip or yoke 2| of metal which serves as a combined support and handle. In order to operate the device, after a sealing plug has been placed on the spring Wire holder, the device is screwed down firmly onto the threaded portion of the flange 3, a copper gasket 22 being used to provide a more intimate contact. A'rubber hose (not shown) is then forced on the tapered tubing or nipple 8 and the tank l evacuated in the usual manner. vacuum has been obtained, and in the case o f gas or vapor devices, after the gas or vapor has been introduced, the double-armed lever I9 is released by moving the yoke 2| to the left as shown in Fig. 2, and the atmospheric pressure operating on the cap I2 causes the sylphon to collapse and to force the sealing plug into the opening of the steel nange. In order to prevent the lever from moving a distance more than is necessary, i. e. so that it will just simply clear the cap l2, stop pins 23 may be provided on opposite sides of the member .6. There is also a pair of pins 24 located near the pins 23 to limit the movementof the arms I9 in the other direction. Y Y

Whenthe plug I8 has been rmly seated in Vthe openings, the cap l2 is preferably struck several blows with a hammer in order to complete the seal'between the plug andthe opening. These hammer blows are communicated to the plug through the ram I6. The sealing device may then be unscrewed from the tank. As an added precaution, the top of the sealing plusr and iiange may besoldered.

From the foregoing, it isY evident that I have disclosedV a sealing device which employs allmetal parts and necessitates in its use, simply a metal flange member welded to the Ytank and provided with threads. The improved arrangement eliminates the need for any glass seals and consequently, permits the manufacture of highly evacuated all-metal tanks which contain electrical apparatus, electrodes, etc. .Y

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A device for sealing off an evacuated metal tank provided with an opening, said device com- After the properV prising means for holding a sealing plug at a position remote from said opening but in line therewith, said means comprising a hollow metal member which iits over the tank opening, and a collapsible air-tight member which closes the opening in said metal member and which carries the sealing plug, the interior of said member being subjected to the rareed conditions in the tank and the exterior of said member being eX- posed to the atmosphere and means for releasing the holding means whereby the sealing plug is permitted to move toward the tank and to be forced into the opening by atmospheric pressure, said releasing means comprising aY pair of interconnected arms rotatably mounted on opposite sides of said hollow metal member and adapted to be moved from a position in which they engage the collapsible member toV a position entirely free of said member.

2. Apparatus for forcinga sealing plug into an opening in an evacuated metal tank, said apparatus comprising in combination, a metal member having a central aperture and adapted to be secured to the tank in line4 with said opening, a collapsible metal tubing secured to said member and closed at the end remote from the tank by a cap whereby the interior of said tubing is subjected to the rareed conditions of the tank and the exterior of said tubing is exposed to the atmosphere, a rod secured to said capV and extending through the aperture in said member, said rod being adapted to receive a sealing plug which is temporarily positioned Within the interior of said metal member in line with the opening in said tank, an evacuating conduit secured to said member and communicating with the interior of the tank, a pair of interconnected arms mounted on opposite sides of said member, saidarms being of a length suicient to engage said cap and to hold the collapsible tubing in an extended position, said arms being adapt- Y

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