Method and control system for controlling multiple compressors

A method of operating a compressor system having a plurality of compressors, wherein each of the compressors is capable of compressing a fluid at a predetermined volumetric flow rate capacity, said method comprising the steps of:

• establishing a set-point pressure;
• measuring the pressure of the fluid in the compressor system;
• measuring the volumetric flow rate capacity of the fluid within the compressor system;
• determining which of the compressors are operating;
• determining the online volumetric flow rate capacity, wherein the online volumetric flow rate capacity is equal to the sum of corresponding predetermined volumetric flow rates for each of the operating compressors;
• loading one of the plurality of compressors upon sensing that the pressure of the fluid in the compressor system is less than the set-point pressure and that the volumetric flow rate capacity is equal to or greater than the online volumetric flow rate capacity.

A control system for controlling a compressor system, comprising:

• a plurality of compressors, each of said compressors being capable of compressing a fluid at a predetermined volumetric flow rate capacity and predetermined pressure, each of said compressors emitting an operational signal indicative of whether said corresponding compressor is operating;
• a pressure sensor for measuring the pressure of the fluid within the compressor system;
• a flow meter for measuring the volumetric flow rate capacity of the fluid within the compressor system;
• a controller having a programmed set-point pressure, said controller having programmed values representing said predetermined volumetric flow rate capacity and pressure for each of said compressors, said controller receiving said operational signals from said plurality of compressors, said controller determining an online volumetric flow rate capacity, wherein the online volumetric flow rate capacity is equal to the sum of said corresponding predetermined volumetric flow rates for each of said operating compressors, said controller determining an excess volumetric flow rate capacity of the compressor system, wherein the excess volumetric flow rate capacity is equal to the online volumetric flow rate capacity minus the measured volumetric flow rate capacity, said controller producing an unloading signal for one of said plurality of compressors upon sensing that the pressure of the fluid in the compressor system is greater than the set-point pressure and the corresponding volumetric flow rate capacity for said compressor is less than the excess volumetric flow rate capacity.

A control system for controlling a compressor system, comprising:

• a plurality of compressors, each of said compressors being capable of compressing a fluid at a predetermined volumetric flow rate capacity and predetermined pressure, each of said compressors emitting an operational signal indicative of whether said corresponding compressor is operating;
• a pressure sensor for measuring the pressure of the fluid within the compressor system;
• a flow meter for measuring the volumetric flow rate capacity of the fluid within the compressor system;
• a controller having a programmed set-point pressure, said controller having programmed values representing said predetermined volumetric flow rate capacity and pressure for each of said compressors, said controller receiving said operational signals from said plurality of compressors, said controller determining an online volumetric flow rate capacity, wherein the online volumetric flow rate capacity is equal to the sum of said corresponding predetermined volumetric flow rates for each of said operating compressors, said controller producing a loading signal for one of said plurality of compressors upon sensing that the pressure of the fluid in the compressor system is less than the set-point pressure and the volumetric flow rate capacity is equal to or greater than the online volumetric flow rate capacity.