Flow rate control for a variable stroke pump
First Claim
1. A system for controlling the throughput of a metering pump, the pump including a pumping member driven by a transmission member for converting rotary motion of a reversible drive motor into reciprocating motion of the pumping member, the system comprising means for adjusting the amplitude of the reciprocating motion and means for adjusting the period of said motion, wherein the means for adjusting the amplitude of said reciprocating motion comprise:
- an optical encoder constrained to rotate with a rotary component of the transmission member driven by the motor for emitting a plurality of pulses with the number of emitted pulses being converted into an analog value which is a function of the value of the amplitude of the displacement;
a comparator for comparing said analog value with an adjustable reference value and for emitting an output signal when the compared values are equal; and
an electronic control circuit for receiving the signal emitted by the comparator at an input, and responding to said signal firstly by switching over the power supply to the motor in order to reverse its direction of rotation, and secondly by activating a counter for counting pulses of the A.C. power supply to the motor, said counter being reset to zero each time a pulse is emitted by the optical encoder, said encoder including an inactive range in the vicinity of the origin position during which no pulses are emitted, the counter sending a signal to the electronic circuit when its pulse count is equal to a reference value, with the electronic circuit responding thereto by switching off the power supply to the motor;
and wherein the means for adjusting the period of the motion are constituted by a pulse generator for sending pulses to the electronic circuit which responds thereto by powering the motor so as to move the transmission member away from said origin position.
1 Assignment
0 Petitions
Accused Products
Abstract
A system for controlling the throughput of a metering pump, the pump including a pumping member (8) driven by a transmission member (4) for converting rotary motion of a reversible drive motor (1) into reciprocating motion of the pumping member, the system comprising means for adjusting the amplitude of the reciprocating motion and means for adjusting the period of said motion. The means for adjusting the amplitude of said reciprocating motion comprise: a sensor (23) for sensing the displacement of the transmission member (4) and for emitting a value which is a function of the value of the amplitude of the displacement; a comparator (21) for comparing said value with an adjustable reference value (20) and for emitting an output signal when the compared values are equal; and an electronic control circuit (24) receiving the signal emitted by the comparator (21) at an input, and responding to said signal firstly by switching over the power supply to the motor (1) in order to reverse its direction of rotation, and secondly by activating detection means (22) for detecting that the transmission member has returned to an origin position; said detection means (22) sending a signal to the electronic circuit when the origin position is reached, with the electronic circuit (24) responding thereto by switching off the power supply to the motor (1); and the means for adjusting the period of the motion are constituted by a pulse generator (28) for sending pulses to the electronic circuit (24) which responds thereto by powering the motor (1) so as to move the transmission member (4) away from said origin position.
-
Citations
9 Claims
-
1. A system for controlling the throughput of a metering pump, the pump including a pumping member driven by a transmission member for converting rotary motion of a reversible drive motor into reciprocating motion of the pumping member, the system comprising means for adjusting the amplitude of the reciprocating motion and means for adjusting the period of said motion, wherein the means for adjusting the amplitude of said reciprocating motion comprise:
-
an optical encoder constrained to rotate with a rotary component of the transmission member driven by the motor for emitting a plurality of pulses with the number of emitted pulses being converted into an analog value which is a function of the value of the amplitude of the displacement; a comparator for comparing said analog value with an adjustable reference value and for emitting an output signal when the compared values are equal; and an electronic control circuit for receiving the signal emitted by the comparator at an input, and responding to said signal firstly by switching over the power supply to the motor in order to reverse its direction of rotation, and secondly by activating a counter for counting pulses of the A.C. power supply to the motor, said counter being reset to zero each time a pulse is emitted by the optical encoder, said encoder including an inactive range in the vicinity of the origin position during which no pulses are emitted, the counter sending a signal to the electronic circuit when its pulse count is equal to a reference value, with the electronic circuit responding thereto by switching off the power supply to the motor; and wherein the means for adjusting the period of the motion are constituted by a pulse generator for sending pulses to the electronic circuit which responds thereto by powering the motor so as to move the transmission member away from said origin position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
Specification