Apparatus for Inhibiting the Propagation of a Flame Front

Abstract

Apparatus is described for inhibiting the propagation of a flame front ignited by a pumping mechanism drawing a waste stream from a process chamber. A combustion chamber comprises an inlet for receiving the waste stream exhaust from the pumping mechanism and means for generating a flame for burning a flammable component of the waste stream. A pressure detector detects a pressure at a location through which the waste stream is drawn by the pumping mechanism, and a flame detector detects the presence of a flame in th combustion chamber. A controller regulates the delivery of at least one process fluid to the process chamber if the detected pressure is greater than a pressure above which the flame front can be sustained by the waste stream, or if there is no flame present in the combustion chamber.

1 . Apparatus for inhibiting the propagation of a flame front ignited by a pumping mechanism of a vacuum pumping arrangement drawing a waste stream from a process chamber, the apparatus comprising:
 means for detecting a pressure at a location through which the waste stream is drawn by the pumping mechanism; and   means for regulating the delivery of at least one process fluid to the process chamber when the detected pressure is greater than a pressure above which the flame front can be sustained by the waste stream.   
   
   
       2 . The apparatus according to  claim 1  comprising a foreline for conveying the waste stream from the process chamber to the pumping mechanism, wherein the detection means is arranged to detect the pressure within the foreline. 
   
   
       3 . The apparatus according to  claim 1  wherein the regulating means comprises at least one shut off valve for preventing delivery of at least one process fluid to the process chamber. 
   
   
       4 . The apparatus according to  claim 1  wherein the regulating means comprises a controller for receiving a signal indicative of the detected pressure. 
   
   
       5 . The apparatus according to  claim 4  wherein the shut off valve is controlled by the controller. 
   
   
       6 . The apparatus according to  claim 1  wherein the vacuum pumping arrangement comprises a further pumping mechanism located upstream of the pumping mechanism. 
   
   
       7 . The apparatus according to  claim 1  comprising a booster pump located upstream from the pumping mechanism. 
   
   
       8 . The apparatus according to  claim 1  wherein means for cooling the waste stream is provided between the process chamber and the pumping mechanism. 
   
   
       9 . The apparatus according to  claim 8  wherein the cooling means comprises a booster pump. 
   
   
       10 . The apparatus according to  claim 8  wherein the cooling means comprises an internal cooling mechanism located within the foreline. 
   
   
       11 . The apparatus according to  claim 10  wherein the internal cooling mechanism is one or more of the group of one or more cooling baffles, one or more cooling fingers and one or more cooling coils. 
   
   
       12 . The apparatus according to  claims 8  wherein the cooling means comprises an external cooling mechanism located adjacent the outer surface of the foreline. 
   
   
       13 . The apparatus according to  claim 12  wherein the external cooling mechanism is one or more of the group of a Peltier device and a cooling coil. 
   
   
       14 . The apparatus according to  claim 1  comprising an exhaust pipe connected to an exhaust of the vacuum pumping arrangement, wherein the pipe is configured to inhibit escalation to detonation of a deflagration occurring therein. 
   
   
       15 . The apparatus according to  claim 14  wherein the exhaust pipe comprises at least one of the group of one or more detonation barriers, one or more purge ports, one or more sections of varying diameter and one or more sections of varying orientation. 
   
   
       16 . The apparatus according to  claim 1  comprising means for delivering inert gas into the waste stream in dependence on the detected pressure. 
   
   
       17 . The apparatus according to  claim 16  wherein the inert gas delivering means comprises at least one purge port located within a stator of the pumping mechanism. 
   
   
       18 . The apparatus according to  claim 16  wherein the inert gas delivering means comprises at least one purge port for introducing inert gas to the waste stream exhaust from the pumping mechanism. 
   
   
       19 . The apparatus according to  claim 16 , wherein the inert gas delivery means comprises heating means configured to heat purge gas prior to delivery thereof. 
   
   
       20 . The apparatus according to  claim 1  comprising abatement apparatus for receiving the waste stream exhaust from the pumping mechanism. 
   
   
       21 . The apparatus according to  claim 20  wherein the abatement apparatus comprises a combustion chamber having an inlet for receiving the waste stream exhaust from the pumping mechanism, and means for generating a flame for burning a flammable component of the waste stream within the combustion chamber. 
   
   
       22 . The apparatus according to  claim 21  comprising means for detecting the presence of a flame in the combustion chamber. 
   
   
       23 . The apparatus according to  claim 22  wherein the regulating means is configured to regulate the delivery of at least one process fluid to the process chamber when no flame is detected within the combustion chamber. 
   
   
       24 . The apparatus according to  claim 22  comprising means for delivering inert gas into the waste stream exhaust from the pumping mechanism when there is no flame is detected within the combustion chamber. 
   
   
       25 . The apparatus according to  claim 20  wherein the inlet of the combustion chamber is configured to prevent a flame from the combustion chamber from propagating into the waste stream upstream from the combustion chamber. 
   
   
       26 . An apparatus for inhibiting the propagation of a flame front ignited by a pumping mechanism drawing a waste stream from a process chamber, the apparatus comprising:
 a combustion chamber comprising an inlet for receiving the waste stream exhaust from the pumping mechanism and means for generating a flame for burning a flammable component of the waste stream;   means for detecting a pressure at a location through which the waste stream is drawn by the pumping mechanism;   means for detecting the presence of a flame in the combustion chamber; and   means for regulating the delivery of at least one process fluid to the process chamber either when the detected pressure is greater than a pressure above which the flame front can be sustained by the waste stream or when there is no flame present in the combustion chamber.   
   
   
       27 . An apparatus for inhibiting the propagation of a flame front ignited by a pumping mechanism drawing a waste stream from a process chamber, the apparatus comprising:
 a combustion chamber comprising an inlet for receiving the waste stream from the pumping mechanism and means for generating a flame for burning a flammable component of the waste stream;   a flame detector for detecting the presence of a flame within the combustion chamber; and   means for regulating the delivery of at least one process fluid to the process chamber when there is no flame present in the combustion chamber.   
   
   
       28 . The apparatus according to  claim 27  comprising means for delivering inert gas into the waste stream exhaust from the process chamber when there is no flame is detected within the combustion chamber. 
   
   
       29 . The apparatus according to  claim 27 , wherein the inlet of the combustion chamber is configured to prevent a flame from the combustion chamber from propagating into the waste stream upstream from the combustion chamber. 
   
   
       30 . A method of inhibiting the propagation of a flame front ignited by a pumping mechanism drawing a waste stream from a process chamber, the method comprising the steps of:
 detecting a pressure at a location through which the waste stream is drawn by the pumping mechanism; and   regulating the delivery of at least one process fluid to the process chamber when the detected pressure is greater than a pressure above which the flame front can be sustained by the waste stream.   
   
   
       31 . A method of inhibiting the propagation of a flame front ignited by a pumping mechanism drawing a waste stream from a process chamber, the method comprising the steps of:
 detecting the presence of a flame in a combustion chamber for receiving the waste stream exhaust from the pumping mechanism; and   regulating the delivery of at least one process fluid to the process chamber when there is no flame present in the combustion chamber.   
   
   
       32 . A method of inhibiting the propagation of a flame front ignited by a pumping mechanism of a vacuum pump drawing a waste stream from a process chamber, the method comprising the steps of:
 detecting the presence of a flow of purge gas into the vacuum pump; and   regulating the delivery of at least one process fluid to the process chamber when there is no purge gas being delivered.