US2672266A - Vacuum leak check valve - Google Patents

Description

March 16. 1954 J. R. MORIN ET AL VACUUM LEAK CHECK VALVE 2 Sheets-Sheet 1 Filed Dec. 19, 1950 INVENTORS JOSEPH R.MORH \I ERIC L. MIDGLEY AK AYMOND P. CROWLEY We. 4% ATTORN -Y March 16, 1954 J. R. MORlN ET AL 2,672,266

VACUUM LEAK CHECK VALVE Filed Dec. 19, 1950 2 Sheets-Sheet 2 INVENTORS F Q C L MISGL Q ERAYMO'ND g CROWLEY ATTORN Y Patented Mar. 16, 1954 UNITED STATES ATENT OFFICE VACUUM LEAK CHECK VALVE Joseph R. Morin, Ipswich, Eric L. Midgley, Salem,

and Raymond P. Crowley, Danvers, Mass, as-

ors to Sylvania Electric Products Inc.,

2 Claims.

This invention relates to vacuum systems for electric lamps, radio tubes, gaseous discharge devices and the like, and more particularly to a leak check valve therefor.

In the manufacture of electric lamps, radio tubes, gaseous discharge devices and the like, these articles are usually evacuated on high speed machinery where several of them are connected through a manifold to a common vacuum pump. Usually two or morevacuum pumps are employed, one being termed a rough vacuum and the other a fine vacuum. The former is employed. at the start of the evacuation process and then the latter is used. In some cases depending on the nature of the article and the degree of evacuation desired, more than one rough vacuum pump and/or morethan' one fine vacuum pump are employed.

One of the problems involved in the simultancous evacuation of several articles by one pump is that of isolating a leaky article from the others to prevent their contamination. One of the mechanisms commonly employed to effect isolation of a leaky article hasbeen a mechanical pinching device disposed in the resilient vacuum line near the exhaust head to which each article is connected. This mechanical pinching device is usually actuated electrically by a relay which is, in turn, energized by a leaky article. Since it is not practical to have a complete pinching device assembly for each machine head, usually only one is employed since most leaky articles are discoverable on rough exhaust. Thus the pinching device assembly is usually located at the last rough exhaust station, immediately preceding the fine exhaust, and the leaky article is thereby prevented from contaminating the other articles on fine exhaust.

Although most of the leaky articles are discoverable on the roughexh austin some cases the leak does not develop or is so small that it is not discoverable until later in theexhaust operation. In order to protect the system 'fromicontamination in cases of this type, one or moreupinching devices should be employed in the fine vacuum system as well as in the rough vacuum system. Even when this is .done'hoWev-er, the time lag hetween the development of "a. leak and isolation-of the leaky article is usually too great to: prevent contamination of the system and the other article connected thereto; In some-cases, the

leak is so small that it goes undetected, yet it is large enough to cause' contamination. oi the system.

It is, therefore aniobject-oii this invention-to 2 detect the development of a leak in an article during the evacuation thereof.

Another object of this invention is to provide a vacuum leak check valve which will immediately isolate a leaky article.

A further object of this invention is to provide a vacuum leak check valve which is fully automatic in its operation.

A further object is to provide a vacuum leak check valve which resets automatically.

The foregoing objects and others are attained, in accordance with the principles of our invention, by providing a chamber in the exhaust line of a vacuum system, the chamber containing a ball which normally rests out of a seat in the exhaust line. When actuated by an excessive inrush of air from an exhaust head, the ball moves oil" of the shelf and drops into this seat in the exhaust line and tightly seals off the exhaust line from the exhaust head. Re-setting of the ball in its normal position on the shelf is effected by a magnet which moves the ball thereto from the ball seat.

A specific embodiment of our invention is described in the following specification and illustrated in the accompanying drawings in which:

Figure 1 is a fragmentary plan view of a flucrescent lamp exhaust machine.

Figure 2 is a fragmentary side elevational view of a fluorescent lamp exhaust machine taken along the line 2-2 of Figure 1.

Figure 3 is a plan view of the vacuum leak check valve of our invention.

Figure 4 is a side elevational view of the valve in section taken along the line 4-5 of Figure 3.

Figure 5 is a view partly in section of a modified part of the embodiment of the invention.

In Figures 1- and 2, that portion of a fluorescent lamp exhaust machine shown therein comprises a rotatable turret i supported on a vertical column 2. The turret I comprises a hub 3, a plurality of supporting arms 4 extendin radially therefrom, and a ring plate 5 mounted on the outer ends of the arms 4. A plurality of lamp exhaust heads 6 are mounted on the top face of the ring plate 5. As may be seen in Figure 2, the ring plate 5 is provided with an aperture '1 therein in register with each exhaust head 3, through which an exhaust tube 8 of 'a fluorescent lamp 9 extends. The lamp 9 is supported in position on the exhaust machine by fingers it. A leak check valve ll is mounted on the top face of the ring plateS adjacent to each exhaust head 6, the valve H and the headt being connected toone another by acoupling l2. The leak check valve ii is also connected to a vacuum pump (not shown) through an exhaust line I3 and a manifold I4.

Referring now to Figures 3 and the leak check valve I I comprises a body member I5 having a chamber I6 therein. One end of the body member I5 has an aperture I'I therein, through which the chamber I6 is connected to the exhaust head 6 through the coupling I2. The body member I5 has a shelf I8 formed therein in the chamber IS on which a metal ball I9 is normally disposed. The shelf is tilted back slightly so as to tend to hold the ball in position. The base of the body member I5 is provided with a plug 20, one end of which is provided with a flange 2I on which a ring 22 of resilient material, circular in cross-section, is seated. A sleeve 23 encircles the plug 20, one end thereof engaging the ring 22. A second ring 24 of resilient material, circular in cross-section, encircles the plug and engages the other end of the sleeve 23. A thimble 25 is disposed on the plug 20 beneath ring 24. Ring 22, sleeve 23, ring 24 and thimble 25 are retained in position by a knurled nut 26 on the bottom of the plug 20.

The wall of the body member I5 is provided with an aperture 21 in which an exhaust line coupling 28 is threaded. The top of the plug 29 is counter-bored to provide a hole 29 therein. Communication between hole 29 in plug 29 and the coupling 28 is established by providing the wall of the plug 20 and the wall of the sleeve 23 with a hole or a plurality of holes in register with one another and in register with the bore of coupling 28. The top of plug 20 is dished about the periphery of hole 29 and a ring 3'1 of resilient material, circular in cross-section, is disposed therein, thus providing a seat for the metal ball I9 when the ball is located in this portion of chamber I6.

Referring now to Figures 1 and 2, a pair of arms 3I, one of which is shown, are attached to the vertical column 2 above the manifold I4. A plate 32 is mounted on the outer end of the arms 3I. A pair of arms 33 are attached to the plate 32, their outer ends being disposed above the ring plate 5 of turret I. Magnets 34 and 49, held in yokes 35, mounted in ball-and-socket joints 36 depend from the outer end of arms 33. The magnets 34 and 40 are disposed immediately above the leak check valves II mounted on the ring plate 5 of the turret I. The use of ball-and-socket joints 36 permits considerable adjustment of the disposition of the magnets 34 and 39.

In Figure 4, the ball I9 is shown as a hollow metal sphere which seats on the ring 37 when actuated by a leaky lamp. In Figure 5 an alternative modification of the ball is shown. The ball of Figure 5 is a hollow rubber sphere 38 with a filling of metal filings 39. When this modification is employed, the ring 31 is not necessary, the rubber ball 38 seating directly in the dished portion on the top face of the plug 29, thereby effecting the desired sealing off of the exhaust head from the vacuum line.

The operation of the leak check valve of our invention will now be described. The fluorescent lamp 9 is positioned on the exhaust machine at station A (Fig. 1), with the exhaust tube 8 thereof in communication with the exhaust head 6 (Fig. 2). It will be assumed, for the purpose of describing this particular cycle of operation, that, at station A, the metal ball I9 is disposed on shelf I8 as shown in Figure 4. The exhaust machine turret I is then indexed, causing the lamp 9 to move to stationB. At station B, the leak check valve I I is disposed beneath the magnet 34 which is of sufficient strength to draw the ball (Fig. 4) upwardly and hold it against the top wall of the chamber I6. With the ball I9 in this position, an unobstructed path is provided from the bore of exhaust head coupling I2 into chamber I6. At station B, the lamp 9 is connected, through exhaust head 6, leak check valve II, and exhaust line I3 to a rough vacuum pump. As the lamp 9 moves from station B to station C, the adjacent legs of the two magnets 34 and 40 retain the ball I9 against the top wall of the chamber I6, and keep it there while the lamp is subjected to a further rough exhaust at station C. At station D, where further rough exhaust is effected, the ball I9 is under the influence of the magnet 40 and is therefore still retained in the elevated position just described.

As the lamp 9 moves from station D to station E, the ball I9 moves outside the magnetic field and therefore drops down to the position shown in Figure 4, on the shelf I9. At station E and at several succeeding stations, the lamp 9 is subjected to a fine exhaust. Since most of the air was pumped out of the lamp at stations B, C, and D, normally the force exerted by the gases being drawn off at station E and subsequent stations is not great enough to blow the ball I9 off of its shelf I9. However, as soon as a leak develops, an abnormally high flow of gas from the exhaust head 9 will occur and blow the ball I9 off of the shelf I9 and cause it to seat on the ring 37. The pressure applied by this abnormal flow of gas into the chamber I6 against the ball I9 (shown in phantom, Fig. 4) will cause the ball i9, in cooperation with the ring 31, to seal off the chamber I6 from the exhaust line I3. In this way, the leaky lamp is automatically and instantaneously isolated from the exhaust line I3 and hence from the rest of the evacuating system. Thus the rest of the system is protected.

from contamination by the leaky lamp.

The ball I9 remains in the position shown in; phantom in Figure 4 throughout the remainder of the rotational cycle of the turret I. The leaky lamp is finally removed by an operator at a station immediately preceding station A. At station A a new lamp is inserted. When this new lamp is moved to station B, the ball I9, under the influence of the magnet 34, will be unseated and drawn upwardly thereby, thus providing an unobstructed path from the chamber I6, through the hole 29 in plug 20 to the bore of the vacuum line coupling 29. Thus the rough pumping at station B is unimpeded. As the lamp moves from station B to station C, the ball I9 is drawn by the magnet 34 across the top wall of chamber I6 until it reaches a position immediately above the opening I! in the wall of the body member I5. The magnet 34 is angularly disposed as shown in Figure 1 in order to make possible this movement of ball I 9 across the top wall of chamber IS. The magnets retain the ball I9 in this position until the lamp moves from station D to station E. At this point, the ball I9 drops down to the position shown in Figure 4, as described above. The ball I9 remains on the shelf I8 for the remainder of the exhaust cycle provided the lamp is not a leaker. If the lamp is leaky, the ball I9 will be dislodged as described above.

The metal of which the several parts of the valve II is made is a non-magnetic material, except that the ball I9 is, of course, made of a magnetic material so that its position may be controlled by the magnets 34 and 40.. Similarly,

5 in the modification shown in Figure 5, the metal filings 39 are made of a magnetic material.

What we claim is:

1. The combination, with a rotatable turret having a pulurality of exhaust heads mounted about the periphery thereof and a plurality of vacuum lines extending radially from the center of the turret to the exhaust heads, of a vacuum leak check valve disposed in each of the vacuum lines between the exhaust heads and the center of the turret, the body of said valve being of non-magnetic material and having a chamber therein normally in communication with the exhaust head and the vacuum line; a ball of magnetic material disposed in said chamber and actuatable by an abnormal flow of gas from an exhaust head to seal off said chamber from the vacuum line; and a magnet disposed above and in register with at least one of said vacuum leak check valves for automatically breaking said seal.

2. The combination, with a rotatable turret having a plurality of exhaust heads mounted about the periphery thereof and a plurality of vacuum lines extending radially from the center of the turret to the exhaust heads, of a vacuum leak check valve disposed in each of the vacuum lines between the exhaust heads and the center of the turret, the body of said valve being of non-magnetic material and having a chamber therein normally in communication with the exhaust head and the vacuum line; a shelf in said chamber, said shelf being inclined upwardly from the horizontal; a ball of magnetic material normally disposed on said shelf and actuatable by an abnormal flow of gas from an exhaust head to seal ofi said chamber from the vacuum line; and a magnet disposed above and in register with at least one of said vacuum leak check valves for automatically breaking said seal and returning said ball to said shelf.

JOSEPH. R. MORIN.

ERIC L. MIDGLEY. RAYMOND P. CROWLEY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,518,461 Smith Dec. 9, 1924 1,933,322 Fagan Oct. 31, 1933 2,254,905 Mullan Sept. 2, 1941 2,565,298 Groat Aug. 21, 1951

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