Static pressure stabilizer for local exhaust

Abstract

An exhaust system is provided for a plurality of machines, each machine having an exhaust stream connected to a local branch of the system. The system includes a stabilizer connected to an exhaust line in parallel to the exhaust stream of a machine. The stabilizer controls an exhaust pressure in the exhaust stream by opening and closing in response to variations in the exhaust pressure; the stabilizer opens to admit gas flow into the exhaust line when the exhaust pressure is less than a predetermined value, and closes when the exhaust pressure is greater than that predetermined value. The stabilizer unit thus provides a constant static exhaust pressure. The stabilizer provides relief flow in the exhaust stream, causing the gas flow into the exhaust line to increase when an exhaust flow in the exhaust stream decreases.

1 . An exhaust system for providing exhaust to a plurality of machines, each machine having an exhaust stream connected to a local branch of the system, comprising: 
 a stabilizer connected to an exhaust line in parallel to the exhaust stream of a machine, wherein said stabilizer controls an exhaust pressure in said exhaust stream by opening and closing in response to variations in said exhaust pressure, the stabilizer opening to admit gas flow into the exhaust line when said exhaust pressure is less than a predetermined value, and closing when said exhaust pressure is greater than said predetermined value.    
   
   
       2 . An exhaust system according to  claim 1 , wherein the gas flow is a flow of ambient air.  
   
   
       3 . A system according to  claim 1 , comprising a plurality of stabilizers, wherein each machine connected to the local branch has a stabilizer connected in parallel thereto.  
   
   
       4 . A system according to  claim 1 , wherein said exhaust pressure is characterized as a static exhaust pressure for the machine, and the stabilizer associated with the machine maintains a constant static exhaust pressure for that machine.  
   
   
       5 . A system according to  claim 3 , wherein said exhaust pressure is characterized as a static exhaust pressure for each machine, and the stabilizer associated with a given machine maintains a constant static exhaust pressure for that machine.  
   
   
       6 . A system according to  claim 1 , wherein said stabilizer causes the gas flow into the exhaust line to increase when an exhaust flow in the exhaust stream decreases.  
   
   
       7 . A static pressure stabilizer for a local exhaust stream of a machine connected to an exhaust system, the static pressure stabilizer comprising: 
 a first pipe having a first end and a second end, the first end connected to the exhaust system and the second end having a first opening therein to admit gas flow;    a second pipe set in the first opening and having a wall with a second opening therein; and    a float inside said second pipe and capable of movement along an axis thereof, so that in a first position of said float the first opening is closed, thereby preventing gas flow into said first pipe, and in a second position of said float the second opening communicates with the first opening, thereby permitting gas flow into said first pipe.    
   
   
       8 . A static pressure stabilizer according to  claim 7 , wherein the gas flow is a flow of ambient air.  
   
   
       9 . A static pressure stabilizer according to  claim 7 , wherein said stabilizer is connected to the exhaust system in parallel to the local exhaust stream, so that said stabilizer is effective to maintain a constant static exhaust pressure for the machine.  
   
   
       10 . A static pressure stabilizer according to  claim 9 , wherein a weight of said float is adjusted in accordance with a desired value of the static exhaust pressure.  
   
   
       11 . A static pressure stabilizer according to  claim 9 , wherein the constant static exhaust pressure has a predetermined value, and said float is given a force in a direction from the first position toward the second position when the static exhaust pressure is less than said value.  
   
   
       12 . A static pressure stabilizer according to  claim 9 , wherein the constant static exhaust pressure has a predetermined value, and said float is given a force in a direction from the second position toward the first position when the static exhaust pressure is greater than said value.  
   
   
       13 . A static pressure stabilizer according to  claim 7 , wherein said float has an end surface, the first opening defines a plane, and an angle of the end surface with respect to said plane remains constant during movement of said float.  
   
   
       14 . A static pressure stabilizer according to  claim 8 , wherein flow of ambient air is permitted into the first pipe in response to a decrease in exhaust flow in the local exhaust stream.