Fluid dispensing system

摘要

An apparatus and method for controlling the opening of a solenoid actuated valve in a sealant dispensing gun are disclosed. A proximity sensor is provided adjacent a portion of the needle valve stem in order to sense when the needle valve has reached its open position. A dispense timer is initiated when the proximity sensor indicates that the needle valve has reached its open position. In this manner, the needle valve may be maintained in its open position for the desired dispense time only without regard to the response time of the solenoid device. Also disclosed is an apparatus and method for adjusting the valve open limit of a sealant dispensing device which incorporates a solenoid or motor actuated valve open limit device. A flow sensor is located in-line with the sealant supply path of a dispensing gun in order to monitor the dispense weight during each valve open cycle. A moving average of the dispense rates may then be calculated and compared to predetermined limits. If the limits are exceeded, the processor the processor automatically adjusts the solenoid or motor actuated valve open limit device in the proper direction in order to bring the dispense rate back into the proper dispense rate range.