Vacuum type sewage collecting system and vacuum valve controller for the

Abstract

A vacuum type sewage collecting system, for collecting sewage from a plurality of houses or the like, stores sewage in a sewage reservoir and then delivers the sewage to a sewage treatment station through a vacuum valve and a vacuum sewage pipe. A controller is provided for properly controlling opening/closing operations of the vacuum valve. The controller includes a first vacuum chamber connected to the vacuum sewage pipe via a fluid flow resisting device, a second vacuum chamber likewise connected to the vacuum sewage pipe, an atmospheric pressure introducing unit for introducing an atmospheric pressure into the first vacuum chamber when a detected quantity of sewage stored in the sewage reservoir exceeds a predetermined value, and a shifting unit for selectively introducing negative pressure to the vacuum valve to open or close the latter depending on the present differential pressure between the first vacuum chamber and the second vacuum chamber. A first opening/closing valve is disposed in a parallel relationship relative to the fluid flow resisting device such that the first opening/closing valve is closed when the negative pressure in the vacuum sewage pipe is lower than a preset value. Alternatively, a closed type air tank is connected to the first vacuum chamber via a second opening/closing valve such that the second opening/closing valve is opened when the negative pressure in the vacuum sewage pipe is lower than the preset value.