| 摘要 |
<p>The valve comprises a discharge pipe with open end facing upwards beneath the water surface and spaced from the tank wall. A vertical, cylindrical, valve support, rigidly fixed to the tank, is suspended coaxially to extend partly into the open end of the pipe, leaving an annular valve passage between cylinder and pipe. A flexible diaphragm sleeve is end-clamped around the cylinder so that it can be inflated to plug the valve passage and deflated to reopen the passage. Below the upper section of the pipe, which accepts the sleeved cylinder, the pipe dia. is pref. stepped down to less than the outside dia. of the cylinder. This means that vertical adjustment of the cylinder alters the effective cross-section of the valve passage to preset a max. flow-rate. The sleeve inflation is pref. remote controlled by supply pneumatic or hydraulic fluid via a tube passing down the inside of the cylinder. Used partic in tanks in which waste water is purified first by activated sludge treatment and then sedimentation. The valve can be remote controlled to be fully sealed during treatment and settlement and then fully open for discharge. No sludge is retained in the pipe entry during value closure. The valve passage cross-section is adjustable. The valve creates no upflow which might disturb and entrain sludge.</p> |
