Method of controlling a plurality of compressors

Abstract

Compressed gases are gathered from a plurality of compressors and employed if required. A pressure of compressed gas thus gathered is measured by a pressure sensor to generate a pressure signal, which is transmitted to a control. The signal is transmitted from the control to electromagnetic switches to control motors for the compressors to determine which of the compressors run.

What is claimed is:  
     
         1 . A method of controlling a plurality of compressors, comprising the steps of: 
 gathering compressed gases outputted from said plurality of compressors which have approximately the same capability;    measuring pressure of a compressed gas thus gathered to transmit a pressure signal to control said plurality of compressors;    dividing the pressure of the compressed gas between upper and lower limits into a plurality of pressure levels which are equal in number to said compressors; and    determining which of the compressors run when the pressure signal reaches the boundary of said pressure levels.    
     
     
         2 . A method as claimed in  claim 1  wherein the compressed gases are gathered into a pressure tank from said plurality of compressors.  
     
     
         3 . A method as claimed in  claim 1  wherein the pressure of the gathered compressed gas is measured by a pressure sensor to generate a pressure signal.  
     
     
         4 . A method as claimed in  claim 1  wherein the compressed gas is air.  
     
     
         5 . A method as claimed in  claim 1  wherein the pressure signal is transmitted to a control which has a determining portion for determining the number of operating compressors and a selecting portion for starting and stopping any of the compressors.  
     
     
         6 . A method as claimed in  claim 5  wherein the pressure signal is transmitted from the control to electromagnetic switches via an operating portion, said electromagnetic switches being connected to motors for said compressors to turn on and off said compressors.  
     
     
         7 . A method as claimed in  claim 1  wherein the pressure rises to an upper pressure level to decrease the number of operating compressors, while the pressure falls to a lower pressure level to increase the number of operating compressors.  
     
     
         8 . A method as claimed in  claim 1  wherein continuous numbers are allotted to said plurality of compressors, any of the compressors being started and stopped in order of the numbers to change the number of operating compressors.