Pulsed pneumatic control of liquid color pumps

Abstract

A liquid color pump and method for operation thereof includes a diaphragm displaceable into a chamber to displace liquid color therefrom; a pair of solenoid valves, each having an inlet port, an exhaust port, and first and second output ports; a potentiometer sensing displacement position of the diaphragm and a processor actuating the solenoid valves responsively to a diaphragm position sensed by the potentiometer.

The following is claimed: 
     
         1 . A liquid color pump comprising:
 a. a diaphragm displaceable into a chamber to displace liquid color therefrom;   b. a pair of solenoid valves, each having an inlet port, an exhaust port, a first output port connecting to the inlet port when the valve is energized, and a second output port connecting to the inlet port when the valve is not energized;
 i. a first one of the valves having its inlet port connected to a compressed air supply, its first output port connected to the diaphragm, its second output port blocked, and its exhaust port connected to the inlet port of the second valve; 
 ii. the second valve having its first output port connected to atmosphere; 
   c. a potentiometer sensing displacement position of the diaphragm; and   d. a processor actuating the solenoid valves responsively to diaphragm position sensed by the potentiometer.   
     
     
         2 . A liquid color pump comprising:
 a. a diaphragm displaceable into a chamber for displacing liquid color therefrom;   b. a pair of solenoid valves, each valve having an inlet port, an exhaust port, and an output port connected to the inlet port when the valve is energized, and connected to the exhaust port when the valve is not energized;
 i. a first one of the valves having its inlet port connected to a compressed air supply, its output port connected to the diaphragm, and its exhaust port connected to the inlet port of the second valve; and 
 ii. the second valve having its output port connected to atmosphere 
   c. a potentiometer sensing displacement position of the diaphragm;   d. a processor actuating the solenoid valves responsively to diaphragm position sensed by the potentiometer.   
     
     
         3 . A liquid color pump comprising:
 a. a diaphragm displaceable into a chamber to displace liquid color therefrom;   b. a solenoid valve for releasing repeated burst of air to displace the diaphragm into the chamber;   c. a potentiometer for sensing displacement position of the diaphragm; and   d. a processor for repeatedly actuating the solenoid valve to provide the repeated bursts of air responsively to diaphragm position sensed by the potentiometer.   
     
     
         4 . The liquid color pump of  claim 3  wherein the solenoid valve has an inlet port connected to a supply of compressed air and an outlet port that upon valve energization is connected to the diaphragm for flow of air therethrough from the supply to the diaphragm. 
     
     
         5 . The liquid color pump of  claim 4  wherein upon de-energization of the solenoid valve the outlet port connecting to the diaphragm is connected to an exhaust port. 
     
     
         6 . A liquid color pump comprising:
 a. a diaphragm displaceable into a chamber to displace liquid color therefrom;   b. a first solenoid valve when energized supplying compressed air from a supply to the diaphragm and when de-energized, connecting the diaphragm to an exhaust port;   c. a second solenoid valve when energized connecting the exhaust port of the first solenoid valve to atmosphere;   d. a potentiometer for sensing displacement position of the diaphragm; and   e. a processor for actuating the solenoid valve responsively to diaphragm position sensed by the potentiometer.   
     
     
         7 . A method for pumping liquid color comprising:
 a. positioning a diaphragm in a pump housing to displace liquid color out of the pump upon displacement of the diaphragm; and   b. applying compressed air in a series of pulses to the diaphragm by:
 i. opening a valve in a pressurized air supply line leading to the diaphragm thereby permitting air from a pressurized supply to contact the diaphragm; 
 ii. closing an exhaust line valve leading from the diaphragm thereby maintain the air applied to the diaphragm to remain in contact therewith; 
 iii. repeatedly opening the supply line valve thereby applying additional air to the diaphragm until displacement of liquid color is complete; 
 iv. opening the exhaust line valve to allow pressurized air to escape from contact with the diaphragm. 
   
     
     
         8 . The method of  claim 7  further comprising:
 a. sensing position of the diaphragm; 
 b. regulating the opening of the supply line valve in response to sensed position of the diaphragm. 
 
     
     
         9 . The method of  claim 8  wherein the sensing is performed continuously. 
     
     
         10 . The method of  claim 8  wherein the sensing is performed by contacting the diaphragm with a riding member and detecting movement of the member. 
     
     
         11 . The method of  claim 8  wherein sensing is performed by a potentiometer. 
     
     
         12 . The method of  claim 10  wherein the member connects to the potentiometer. 
     
     
         13 . The method of  claim 7  wherein regulating opening of the supply line valve comprises regulating the valve open time. 
     
     
         14 . The method of  claim 7  wherein regulating opening of the supply line valve comprises regulating the valve closed time. 
     
     
         15 . The method of  claim 7  wherein regulating opening of the supply line valve comprises regulating the time between valve openings. 
     
     
         16 . A method for operating a diaphragm pump to pump liquid color, comprising:
 a. providing first and second solenoid valves, each having inlet and exhaust ports and each having two supply ports, a first supply port being connected to the inlet port and a second supply port being connected to the exhaust when the valve is energized, with the first supply port being connected to the exhaust port and the second supply port being connected to the inlet port when the vale is not energized;   b. connecting the inlet port of the first valve to a supply of compressed air;   c. connecting the first supply port of the first valve to the pump diaphragm;   d. connecting the exhaust port of the first valve to the inlet port of the second valve;   e. applying compressed air in a series of pulses to the diaphragm by energizing the first valve thereby permitting air from a pressurized supply to contact the diaphragm while closing the second supply port of the second valve and de-energizing it thereby forcing the compressed air applied to the diaphragm to remain in contact therewith.   
     
     
         17 . The method of  claim 16  further comprising sensing positional displacement of the diaphragm and adjusting the duration of the pulses in response thereto. 
     
     
         18 . The method of  claim 17  further comprising sensing positional displacement of the diaphragm with a potentiometer. 
     
     
         19 . The method of  claim 17  further comprising sensing positional displacement of the diaphragm and using a microprocessor to adjust the duration of the pulses in response thereto. 
     
     
         20 . The method of  claim 16  further comprising adjusting interval timing of the pulses. 
     
     
         21 . The method of  claim 16  further comprising adjusting “on” time of the pulses. 
     
     
         22 . The method of  claim 16  further comprising adjusting “off” time of the pulses. 
     
     
         23 . A method for pumping liquid color, comprising:
 a. providing first and second valves, each having inlet and exhaust ports and each a supply port, the supply port being connected to the inlet port when the valve is energized and being connected to the exhaust port when the valve is not energized;   b. connecting the inlet port of one valve to a supply of pumping fluid;   c. connecting the first supply port of the first valve to a pumping diaphragm;   d. connecting the exhaust port of the first valve to the inlet port of a second valve;   e. applying pressurized fluid in a series of pulses to the diaphragm by energizing the one valve thereby permitting the pressurized fluid to contact the diaphragm while de-energizing the second valve thereby forcing the pressurized fluid applied to the diaphragm to remain in contact therewith.   
     
     
         24 . The method of  claim 23  further comprising sensing positional displacement of the diaphragm and adjusting the duration of the fluid pulses in response thereto. 
     
     
         25 . The method of  claim 24  further comprising sensing positional displacement of the diaphragm with a potentiometer. 
     
     
         26 . The method of  claim 23  further comprising sensing positional displacement of the diaphragm and using a microprocessor to adjust the duration of the pulses in response thereto. 
     
     
         27 . The method of  claim 26  further comprising adjusting interval timing of the pulses. 
     
     
         28 . The method of  claim 26  further comprising adjusting “on” time of the pulses. 
     
     
         29 . The method of  claim 26  further comprising adjusting “off” time of the pulses.