Apparatus for mixing hazardous gas with an airflow

A housing receives ambient air through an inlet located so as to direct the airflow against blades of a rotor which disperses the airflow. A gas inlet conduit discharges hazardous gas into a chamber of the housing. The dispersed airflow acts on the hazardous gas entering the chamber to disperse and mix with the gas. The mixed air and hazardous gas flow impinges against a wall surface of the housing prior to discharge from the housing via an outlet conduit. A source such as the intake side of a blower induces the flow of air and hazardous gas through the housing and the outlet conduit. The rotor is located near an air inlet of the housing for rotor operation by airflow drawn into the housing. A flow sensor and damper control system are provided.

BACKGROUND OF THE INVENTION 
The present invention concerns the rendering of hazardous gases inert by 
dilution of same with an airflow. 
The disposal of hazardous gases, which may include toxic, corrosive and 
explosive gases is of great concern in view of their dangerous nature and 
possible harm to the environment. Such gases result from various 
manufacturing processes including those utilizing chemical vapor 
deposition. Flammable gases also constitute a disposal problem. 
A problem exists in the rendering of some explosive gases inert in view of 
their high volatility which precludes the use of electrical components in 
view of the risk of ignition. Further, the utilization of blowers, fans, 
filters in the treating of corrosive gases renders such components of 
costly manufacture and of limited life. 
One process for reducing such gases to an inert state is that of combustion 
disposal. A degree of risk is still encountered in the conveying of 
hazardous gases from their source, such as a manufacturing process, to the 
combusion site. The formation of gas pockets during conveyance has been 
the cause of injury and death to workers as well as property damage from 
explosion. The conveyance of hazardous gases to a disposal apparatus or 
burner entails the construction of costly ducting not susceptible to the 
formation of pockets of gas or the escape of gas. Such ducting must be of 
non-corrosive materials to further add to the cost of same. 
Governmental restrictions concerning the disposal of hazardous gases are 
being established and it is anticipated that a criteria for disposal will 
be on a parts per million (PPM) basis. 
SUMMARY OF THE PRESENT INVENTION 
The present invention concerns an apparatus for mixing a flow of hazardous 
gas with an airflow within a chamber subjected to below atmospheric 
pressure. 
In a housing defined chamber, both the hazardous gas and an airflow are 
induced by a remote source of negative pressure such as the blower of a 
scrubber unit. A rotor in the housing chamber is disposed so as to be in 
the path of an incoming airflow and serves to disrupt the airflow into 
multiple and diverse currents which act on and mix with the hazardous gas 
delivered into the chamber by an inlet conduit. A discharge end of the 
conduit is disposed downstream from a housing air inlet resulting in the 
induced flow of air currents continuously moving past the discharge end of 
the conduit along diverse and changing paths. 
The mixture of incoming air and hazardous gas continues along a housing in 
a turbulent manner with at least a portion of the mixture impinging 
against a wall of the housing as drawn by a negative pressure in an outlet 
duct. The below atmospheric pressure in the inlet conduit, housing and 
outlet duct avoids the risk of hazardous gas escaping from the present 
apparatus. 
Important objectives of the present apparatus include the provision of a 
housing defining a chamber into which air is drawn and mixed in the 
chamber, with hazardous gas also drawn into the chamber by a source of 
below atmospheric pressure; the provision of the housing including a rotor 
powered by an airflow drawn into the housing with rotor blades imparting 
diverse currents to the flow which disperse and mix with hazardous gas 
prior to entry into an outlet duct; the provision of an apparatus for 
treating hazardous gases which relies on a flow of air induced into the 
housing by a remote source to avoid the risk which otherwise would be 
present if electrically energized components were utilized.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With continuing attention to the drawings, wherein applied reference 
numerals indicate parts similarly hereinafter identified, the reference 
numeral 1 indicates generally a housing defining a chamber 2 receiving a 
flow of hazardous gas via an inlet conduit 3. 
The housing 1 comprises a pair of sidewalls at 4, a top wall 5 and a bottom 
wall 6. An upright end portion 2A of the chamber is defined by the housing 
sidewalls 4, an end wall 7, an intermediate wall 8 and a second top wall 
9. An outlet duct is at 10. Housing 1 is preferably of stainless steel 
construction to handle a range of hazardous gases entering via inlet 
conduit 3. 
Ambient air inlet means at 12 is located in an end wall 13 of the housing 
to receive air for subsequent mixing with the hazardous gas entering via 
inlet conduit 3. Conduit 3 extends internally of the housing and is 
provided with a curved end portion 3A terminating internally of the 
housing in an outlet end 3B. 
In housing 1 is a rotor assembly including a shaft 21 journalled in 
bearings in sidewall mounted collars 22. Said shaft carries multiple 
blades as at 24 each shaped so as to move in response to incoming air 
entering via housing ambient air inlet 12. Blade apertures 24A contribute 
to dispensing the air. 
Air inlet 12 is located so as to direct air drawn into housing toward a 
blade 24 on shaft 21 to drive the rotor assembly and more specifically 
impart turbulence to the incoming flow of ambient air which is induced 
into chamber 2 by a fan or scrubber at 25. Preferably the blades 24 are 
backward curved relative their direction of rotation about an axis A. Such 
blade imparted turbulance is shown by dashed arrows at 26. The turbulent 
air flows past outlet 3B of hazardous gas inlet 3 results in the hazardous 
gas being dispersed per the dashed arrows at 27 as it mixes with turbulent 
air 26. Such mixing continues as the mixture moves along chamber 2. 
Further mixing occurs at 28 when the mixed gas flow encounters wall 7 of 
the housing. The flow is drawn upwardly toward outlet duct 10 in 
communication with a reduced pressure source area such as the inlet of a 
fan or scrubber unit 25. 
A damper 30 in duct 10 is preferably of the locking type and regulates 
mixed gas flow through housing 1 and duct 10. Air flow through outlet duct 
10 is monitored by a flow sensor unit 33 in circuit with an inlet valve 34 
to terminate hazardous gas flow in inlet 3 upon detection of a reduced 
mixed flow in outlet duct 10. The ratio of airflow through outlet duct 10 
to the flow in inlet 3 should be within 100 CFM to 250 CFM to 1 CFM and 
may vary to best treat the hazardous gas being processed. Additional 
sensors and control elements, if so desired, will be readily apparent to 
those skilled in the art. A valve control circuit includes leads 35-36 
from sensor unit 33. 
Inlet means 12 has a medial plane P which is offset from rotor shaft axis A 
to ensure inlet air impinging against rotor blades 24 in a successive 
manner. The blades, preferably apertured, disperse the airflow into 
diverse currents which act on the hazardous gas flow discharged from 
conduit end 3B and mix with same to the extent noted above to render same 
inert. 
The following gases are some of the hazardous gases that may be treated 
with the present apparatus: 
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Hydrogen (flamamble) 
Monosilane (flamamble) 
Butene (flamamble) 
Phosphene (toxic) 
Germane (toxic) 
Chlorine (toxic) 
Dichlorosilane (corrosive) 
Chlorine trifluoride (corrosive) 
Hydrogen chloride (corrosive) 
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While I have shown but one embodiment 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.