The invention relates to a gas cabinet with a housing in which at least one gas bottle is arranged that is connected to a conduit system that is located in the housing and is positioned within a scavenging air flow that enters through at least one intake opening the housing and exits from the housing through at least one exit opening.
In particular in the semiconductor industry gas cabinets are used in which gas bottles containing gases are present which gases are supplied by means of a conduit system to consumers. The gases can be poisonous, corrosive or combustible. For this reason, it is necessary that scavenging air flows through the gas cabinet in order to remove gases that have leaked without the gases reaching the environment in an uncontrolled fashion. Since it is required to provide a minimum air flow rate in the open cross-section of the gas cabinet for a safe removal of gases escaping through leaks at the connectors and pipe conduits above the gas bottle, large amounts of air are required in known configurations of gas cabinets; this leads to significant operating costs.
It is an object of the invention to configure a gas cabinet of the aforementioned kind such that the installation and operating costs are reduced.
This object is solved for a gas cabinet of the aforementioned kind in accordance with the present invention in that the gas cabinet is designed such that the open flow cross-section of the scavenging air passage for the scavenging air in the housing is limited to the amount necessary for a reliable scavenging action.
In the gas cabinet according to the present invention the required volume flow of the scavenging air is reduced by reducing the cross-section. In this way, the flow cross-section for the scavenging air can be minimized such that a reliable scavenging action is just about still possible. In this way, the scavenging air quantity to be removed is reduced to a minimum without this having disadvantageous effects on the safety of the gas cabinet according to the invention.
Advantageously, for limiting the flow cross-section at least one displacement body is used which is arranged within the housing. The displacement body is gas-tight or air-tight so that the gases cannot penetrate into the displacement body but are reliably removed by the scavenging air.
Instead of the displacement body, a reduced housing volume can also be provided. The housing in this case can be provided with reduced width and/or depth in the appropriate areas.
Further features of the invention result from the further claims, the description, and the drawings.
The invention will be explained in more detail with the aid of embodiments illustrated in the drawings. It is shown in:
The gas cabinet has a housing 1 with a back wall 2, sidewalls 3, 4, a front wall 5, a bottom 6, and a ceiling 7. In the housing 1, two gas bottles 8 and 9 are provided that stand on the bottom 6 and are secured in the housing 1 in a way known in the art. The two gas bottles 8, 9 are positioned at a minimal spacing relative to one another and contain gas that is supplied in a known manner to a consumer (not illustrated). Different substances are conceivable as a gas, for example, NH3 or BCl3. The gas bottles 8, 9 each have a gas valve 10, 11 with which they are connected to a gas conduit system 12. The gas conduit system 12 has two conduit branches 13, 14 that are connected to a common exit line 15. The two conduit branches 13, 14 can be closed off, for example, by a valve 16, 17, respectively, relative to the exit line 15. During operation of the gas cabinet, advantageously only one of the two gas bottles 8, 9 is in use. The conduit branches 13 or 14 of the other gas bottle is closed off, for example, by the valve 16, 17 relative to the exit line 15.
In deviation from the illustrated preferred embodiment, the gas cabinet can also have only one gas bottle or more than two gas bottles.
In the area between the gas conduit system 12 and the back wall 2 of the housing a gas-tight displacement body 18 is provided that is embodied as a hollow body. As shown in
Since the wall surface 24 extends between the gas bottles 8, 9 and the back wall 2 of the housing, the displacement body 18 at the level of the gas bottles 8, 9 is provided with a recess 27, 28 (
The front wall 5 of the housing 1 can have a further gas-tight displacement body 18′ that at its exterior side is provided with an operating panel 29 having, for example, a touch-sensitive screen. Moreover, the operating panel 29 is provided at its rear with electronics for the gas cabinet. The front wall 5 of the housing is provided in the area of the operating panel 29 with an opening. It is also possible to arrange the operating panel 29 in the front wall 5 of the housing 1. As shown in
The rear area of the front wall 5 can be somewhat less wide in order to ensure that opening is possible even for housings that are positioned tightly adjacent to one another (opening radius).
The displacement body 18′ that is attached to the inner side of the front wall 5 is positioned at a spacing opposite the lower part of the displacement body 18. The displacement body 18′ extends approximately from the level of the bottom 26 to approximately half the height of the slanted surface 23 of the displacement body 18. Between the displacement body 18′ and the oppositely positioned area of the displacement body 18 a flow chamber 33 is formed that is delimited transversely to the flow direction by the wall surfaces 23, 24 of the displacement body 18 and the inner side 30 of the displacement body 18′. Laterally, the flow chamber 33 is delimited by the housing sidewalls 3, 4. In the area of the slanted wall surface 23 of the displacement body 18 the flow cross-section is reduced, for example, continuously. In the area above the displacement body 18′, the flow cross-section of the flow chamber 39 increases again and, in this area, is delimited by the front wall 22 of the displacement body 18, the front wall 5 of the housing and a part of the housing sidewalls 3, 4.
The flow chamber 33 adjoins in the downward direction a flow chamber 34 that downwardly is delimited by the housing bottom 6 and, circumferentially, by a part of the housing sidewalls 3, 4, the back wall 2, and the front wall 5. Near the bottom end of the flow chamber 34, a closable intake opening 35, 36 is provided, respectively, in the front wall 5 and in an intermediate wall 44 of the housing 1. They are formed advantageously by slides which can be moved into an open position and into a closed position. Further intake openings 37, 38 are located at the upper end of the flow chamber 39 that is in communication via flow chamber 33 with the lower flow chamber 34. The two intake openings 37, 38 are also advantageously formed by slides that are moveable from a closed position into an open position. The intake opening 37 is located in the front wall 5 of the housing. The intake opening 38 positioned at a spacing there behind separates the flow chamber 39 from the flow chamber 40 that is located between the top 25 of the displacement body 18 and the housing ceiling 7. The intake opening 38 is provided in a partition 47 which extends at the level of the front wall 22 of the displacement body 18 from its top 25 to the housing ceiling 7 and extends between the housing sidewalls 3, 4.
By means of the two displacement bodies 18, 18′ the open flow cross-section of the scavenging air passage for the scavenging air within the housing 1 is reduced. The open flow cross-section is only so large that with the scavenging air 41 gases possibly exiting from the gas bottles 8, 9 and/or the conduit system 12 are reliably removed by suction. The critical area of the gas bottles 8, 9, i.e., the area about the gas bottle valves 10, 11, is positioned within the flow chamber 33 whose cross-section is selected to be optimally small. As indicated by the flow arrows in
The displacement body 18 can be flushed or filled with an inert gas, for example, nitrogen, so that it is prevented that combustible gases contained in the displacement body 18 will ignite or dangerous gases will collect. In an exemplary fashion, in the bottom 26 and at the front wall 22 of the displacement body 18 a scavenging valve 45, 46 (
The displacement body 18′ can also be provided with two scavenging valves so that it can be flushed with inert gas.
Above the housing bottom 6 a height-adjustable bottle support surface can be mounted additionally.
In the embodiment according to
In case that in accordance with
The displacement body 18′ has a plane back wall 30 that extends parallel to its front side. In other respects, the displacement body 18′ is identical to that of the preceding embodiment. Advantageously, the displacement body 18′ is formed by an appropriate shaping of the housing front wall 5. For this reason, the displacement body 18′ is open at the front.
The scavenging air 41 passes through the lower intake opening 36 in the housing front wall 5 into the lower flow chamber 34 and flows into the flow chamber 33 between the two displacement bodies 18, 18′. In contrast to the preceding embodiment, the flow cross-section of the chamber 33 decreases continuously in the flow direction. The scavenging air 41 reaches subsequently the upper flow chamber 39 located above the displacement body 18′ and in front of the displacement body 18. The intake opening 37 is closed in accordance with the preceding embodiment and the intake opening 38 is open. The scavenging air 41 reaches thus the flow chamber 40 above the top 25 of the displacement body 18 and exits through the exit 42.
The embodiment according to
The displacement body 18 is provided at the back wall 2 of the housing and can be attached to it as a separate body. Advantageously, it is however also possible to configure the displacement body 18 and the back wall 2 of the housing as a unitary part.
In the described embodiments, the valves 10, 11 of the gas bottles 8, 9 are located in the flow chamber 33. Since the gas valves 10, 11 are the first possible leakage area, leaked gas is reliably entrained by the scavenging air 41 and removed in the described way through the exit 42.
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10 2006 013 942 | Mar 2006 | DE | national |
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Number | Date | Country | |
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20080012458 A1 | Jan 2008 | US |