Abstract:
A mixing chamber receives pyrophoric gas for mixing with oxygen prior to discharge into an upright housing of the apparatus. Tubular members within the housing define annular passageways through which the mixed gas and oxygen flow in a serpentine manner with reversal of flow direction promoting the precipitation of matter. A receptacle is removably attached to the housing for collection of matter with mounting means enabling periodic receptacle removal for cleaning. An enclosure about a housing end includes a door for access to the receptacle. Provision is made for ventilating of the enclosure to an exhaust conduit during door opening to prevent escape of gas and particulate to the atmosphere. A modified form of apparatus includes a filter and chemical bed for further treatment of the flow.

Description:
BACKGROUND OF THE INVENTION 
     The present invention is concerned with the removal of matter from gases including the separation of particulate therefrom. 
     In the manufacture of computer chips hazardous gases are generated which must be reduced to an inert state prior to being vented to the atmosphere. Silane gas, for example, occurs in the manufacture of semiconductors, photovoltaic and flat panels and cannot be vented to the atmosphere in view of its toxicity. The gas is pyrophoric and when oxidized results in the precipitation of particulate. Subsequent to such treatment the gas may be subjected to further processing, as by a scrubber, prior to release to the atmosphere. A co-pending patent application, Ser. No. 09/050,173, is currently pending and is directed toward the treatment of such hazardous gases, and is incorporated herein by reference. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention is embodied in an apparatus which mixes oxygen with a hazardous gas with provision made for convenient removal of particulate collected from the oxidized gas flow. 
     In the apparatus a mixing chamber receives air and a flow of a pyrophoric gas and discharges the combined flows into a separator having a series of radially spaced conduits arranged to direct the combined flow along reversed paths to separate particulate formed from the mixed and burned gases. The separator includes concentric tubular members constraining the mixed flow for travel in those areas defined by adjacent tubular members. A lowermost portion of the separator is located in an enclosure and constitutes a receptacle. Mounting means permits removal of the receptacle from the separator for cleaning purposes without interruption of related manufacturing operations. During cleaning the separator housing is ventilated to prevent the escape of hazardous gas and particulate from the housing interior. Automatic venting of the housing prevents escape of hazardous gas and particulate into the atmosphere during receptacle removal and reinstallation. A modified form of the separator includes added filtering and adsorbent features. 
     Important objectives of the present apparatus include the provision of a separator with concentric tubular members producing a reverse flow of a gas and air mixture with particulate from the mixture gravitating into a detachable receptacle enabling periodic removal of collected matter, the provision of a reverse flow separator including a detachable collector or receptacle located in an enclosure which at all times has a negative atmospheric pressure to preclude the release of hazardous gas to the atmosphere; the provision of a separator having a portion located within an enclosure with opening of the enclosure automatically providing a bypass in communication with a negative pressure source, such as a scrubber of an industrial plant, to prevent escape of hazardous gas to the atmosphere; the provision of a separator which subjects a pyrophoric gas to oxidation, filtration and chemical treatments. These and other objects will become clear upon an understanding of the following described structure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings: 
     FIG. 1 is an elevational view of the present apparatus with fragments broken away to disclose internal structure; 
     FIG. 2 is a fragmentary view of a detachably mounted receptacle of the separator. 
     FIG. 3 is a view similar to FIG. 1 showing a modified form of the separator of the present apparatus. 
     FIG. 4 is a horizontal section taken along line  4 — 4  of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With continuing attention to the drawings, wherein reference numerals indicate parts similarly hereinafter identified, the reference numeral  1  indicates an apparatus for treating pyrophoric gas delivered through a conduit  2 . Indicated at  3  is a structure defining a mixing chamber  4  in which the hazardous gas flow is received. A conduit  5  terminates at-conduit  3  and provides an oxygen flow for mixing with the hazardous gas as later described. 
     An upright housing is indicated generally at  7  and receives the discharge from chamber  4 . Arrows  8  indicate the discharge of the products of combustion to the interior of a cylindrical component  10  of housing  7 . A top plate  11  closes the upper end of cylinder  10  which terminates downwardly in a flanged end  12  to support a receptacle  13  having a bottom wall  13 A. With continuing attention to housing  7 , internal cylinder  14  depends from top plate  11  and terminates downwardly in receptacle  13  offset from bottom wall  13 A. A third cylinder  15  depends from top plate  11 , by means of hangers at  16 , and is concentric with outer cylinder  14  but spaced therefrom to provide an annular passageway  17 . Other passageways are at  18  and  19 . An exhaust conduit  20  extends substantially the length of cylinder  15  and is offset from receptacle bottom  13 A at its lowermost end  21  to receive an upward flow for discharge into an outlet  22  in communication with a below atmospheric pressure source which may be embodied in a scrubber apparatus. Cylinder  15  is in endwise abutment with receptacle bottom  13 A to constrain the flow to upward passage in outlet  22 . 
     Housing  7  is closed at its lower end by receptacle  13  having the general shape of a pan flanged at  25 . With attention to FIG. 2, it will be seen that mounting means for receptacle  13  are provided by a ring  26  having lugs  27  spaced about the ring inner perimeter to provide circumferentially spaced openings through which receptacle lugs  28  may pass during receptacle installation and removal. Ring  26  is mounted to cylinder flange  12  as by fasteners  29  located at intervals about the flange. The foregoing mounting means is similar to that utilized, as for example, in pressure cookers utilized in food preparation. A seal  31  extends about ring  26  for seating abutment with receptacle flange  25 . 
     From the foregoing it will be seen that the mixed oxygen and pyrophoric gas products enter housing  7  and pass downwardly intermediate housing outer wall  10  and internal cylinder  14  for entry into receptacle  13  whereat the flow is reversed for upward passage through passageway  17  intermediate second cylinder  14  and cylinder  15 . A subsequent travel of the flow is downwardly in passageway  19  defined by cylinder  15  and exhaust conduit  20 . A final reversal of the mixed oxygen and gas flow occurs adjacent bottom wall  13 A of the receptacle for upward discharge via conduit  20  into outlet  22 . 
     With attention still to FIG. 1, an enclosure at  30  is in place about the lower portion of housing  7  and is vented at  30 A to the atmosphere to admit ambient air for entry into conduit  5  serving mixing chamber  4 . Conduit  5  is apertured at  5 A. 
     Housing  30  is periodically ventilated by a conduit  33  terminating in communication with outlet  22 . A solenoid  34  serves to position a baffle  35  to close conduit  33  upon housing  30  being momentarily opened to the atmosphere when a door  36  is opened by an operator of the apparatus. Latches  38  normally retain door  36 , hinged at  37 , closed. Opening of door  36  actuates a switch at  40  to energize solenoid  34  to open baffle  35  for ventilation of the enclosure  30  as induced by the below atmospheric pressure source acting on outlet  22 . Accordingly matter is prevented from escaping enclosure  30 . 
     Operation of the apparatus is believed to be apparent from the foregoing. During operation receptacle  13  will collect precipitating matter resulting from the burning of a pyrophoric gas mixed with oxygen in chamber  3  and the tortuous serpentine flow through housing  7 . Receptacle  13  is periodically detached by means of mounting means  26  from outer wall  10  of the housing to permit removal for discharge of collected particulate at P. Receptacle removal is achieved by arcuate rotation of same to disengage lugs  27  and  28  subsequent to which the receptacle may be moved downwardly in housing  30  and thereafter extracted outwardly through door opening  39 . Openings  31  in housing  30  admit an ambient air flow into the housing for passage across the housing and into conduit  5  to purge any fumes that may collect in the housing during operation of the apparatus. 
     In FIG. 3, a modified form of the apparatus, generally at  51 , is disclosed which additionally provides filtering and chemical treatment of the products from the burned pyrophoric gas. The modified apparatus at  51  is served by an inlet conduit  52  providing a hazardous gas flow into enclosure  53  defining a mixing chamber  54 . An air flow is admitted to mixing chamber  54  by a conduit  55 . A housing is indicated generally at  57  including an outer cylindrical component  60  terminating upwardly in a flange to receive a top plate  61 . Component  60  is equipped with a bottom flange at  62  to which is attached, as later described, a receptacle  63 . Interiorly of component  60  is a cylinder  64  to define a passageway  68  there-between through which flows, in a downwardly direction, the products of burned pyrophoric gas. A second cylinder  65  defines, with cylinder  64 , still another passageway at  67  for the upward travel of the combustion products. Hangers at  66  support cylinder  65  in a manner providing an inlet upper end for the products which subsequently flow downwardly in a passageway  69  intermediate cylinder  65  and an exhaust conduit  70 . Cylinder  65  terminates in abutment with receptacle  63 . Accordingly the gas flow through housing  57  will be similar to the gas flow through the first described form of the separator apparatus. 
     With attention again to receptacle  63 , the same includes a side wall  73  and a bottom wall  74  with the side wall terminating upwardly in a flange  75 . Suitable mounting means includes ring  76  secured to flange  62  of cylinder  60  by fasteners  79 . Ring  76  and flange  75  of receptacle  63  are provided with mounting means including interengageable lugs similar to that earlier described with the first described form of the invention to enable receptacle removal upon arcuate positioning of same. 
     An enclosure  80  is in place about the lower end segment of a separator housing  57 . A conduit  83  serves to ventilate enclosure  80  upon opening of a housing door  86  as earlier described in the description of the first form of the invention. A door opening is at  89 . Djwr latches are at  88 . A solenoid is at  84  to position a baffle  85  as earlier described wherein a door activated switch (of the type shown in FIG. 1) closes a circuit, when opened, to solenoid  84 . 
     With further attention to receptacle  63 , the same is provided with radially spaced circular walls at  90  and. 91  which are perforate to allow the passage of the flow being treated. A circular filter  92  occupies the annular space between wall  90  and side wall  73  of the receptacle to initially filter the incoming gas flow prior to initial reversal of flow direction upwardly through passageway  67 . Circular wall  91  serves to confine a chemical bed  93  through which the gas from passageway  69  must flow prior to entry into exhaust conduit  70 . The space defined by circular wall  91  is filled with a chemical agent such as a silical jell or a carbon bed for adsorption of toxic matter. Circular wall  91  is also perforate to admit gas flow about its perimeter with the flow ultimately passing upwardly through outlet conduit  70  in communication with a source of below atmospheric pressure. 
     In operation of the modified form of separator the flow from mixing chamber  54  passes downwardly about the exterior of cylinder  64 , through filter  92  which may be of stainless steel composition, thence through passageways  67 ,  69  and into chemical bed  93  and ultimately drawn upwardly through the outlet  70  toward the low pressure source. 
     Toxic gases such as arsine AsH 3  and global warming gases such as hexafluoroethane C 2 F 6  are abated by chemical bed  93  in receptacle  63 . 
     It will be noted that the cylinders  64  and  65  and outlet conduit  70  are concentric about a vertical axis  8  which is preferably offset from the axis at A of housing  60  thereby avoiding restriction of the flow outward from mixing chamber  64 . 
     While I have shown but a few embodiments of the invention, it will be apparent to those skilled in the art that the invention may be embodied still otherwise without departing from the spirit and scope of the invention. Having thus described the invention, what is desired to be secured by a Letters Patent is: