Automatic control device for the regeneration of ion-exchange resins

Claim 1

An automatic control device for the regeneration of an ionexchange resin, said device comprising two pairs of electrodes positioned within a bed of said resin, a first of said pairs being positioned upstream of the other of said pairs; a Wheatstone bridge detection circuit, the four legs of which respectively comprise said first pair of electrodes, said second pair of electrodes, a rheostat and an auxiliary resistance, said detection circuit adapted to produce a voltage when the electrical properties of said resin at the levels of said pairs of electrodes differ; a threshold amplifier connected to amplify said voltage; a relay operable in response to said amplified voltage; a motor for operating said regeneration and selectively actuated by said relay; a diode and capacitor means associated with said amplifier and relay for retarding the operation of said relay and thereby selectively delaying the commencement of said regeneration, said capacitor being charged by the low inverse current of said diode and thus having a low charge, and said diode being conductive when the discharge of said capacitor takes place, said diode further adapted to avoid accumulation of false information; a cam mounted on said motor and movable when said motor operates; a first microswitch adapted to be closed by said cam when said motor rotates, a second microswitch and a rotating timing device, said first microswitch when closed adapted to break current to said detection circuit and thereby stop the operation of said motor, but also adapted to send current through said second microswitch by means of said rotating timing device whereby said motor is again operated.