Dental treatment waste water separator - has servo valve opening control to prevent build=up on intermediate store wall

摘要

The system to separate solid particles from the waste water, at a dental treatment station, has a switched separation (12,14) to pass the solids to a collection container and the water to a clean water outlet (40) with a control system (124). At the end of the activating signal for the separation unit (12,14), the control circuitry (134,142,144) holds the servo valve (22) open for a given time span independently of the signal to show the level in the intermediate store in front of the inlet to the separator (12,14). Pref. the separator (12,14) has an air separation cyclone (14) which is connected to an underpressure source (130) by a circuit (124) which prepares a valve opening signal only if no other activating signal is in force. The servo valve (22) has a single action setting cylinder, operated by compressed air, with a cover over the piston head end with an outflow opening, closed at a tongue value of an elastic material with a beading towards the piston end side, working together with the piston. ADVANTAGE - The operation prevents build-up of deposits on the walls of the intermediate store at the level which trips the level switch sensor.