| 摘要 |
927.667. Filters. UNION TANK CAR CO. Feb. 13, 1962 [Aug. 30, 1961], No. 5534/62. Class 46. A filter of the self-backwashing type comprises a filter tank 1, at least one filter chamber 2 containing a filter bed 5, e.g. sand, a backwash storage compartment 11 in communication with the outlet side 2b of the chamber through at least one connecting duct 10, an inlet pipe 22, a filtered liquid outlet 12, a backwash outlet pipe 23, and a transfer conduit 6 in communication at its one end with the inlet side 2a of the chamber and in common communication at its other end with the inlet pipe and the backwash outlet pipe. Means for automatically controlling the backwash cycle comprises a butterfly valve 18 for controlling the flow of liquid through the backwash outlet pipe, an electrical actuating means 17 for opening and closing the valve, a high level control pipe 14 in communication with the inlet side of the chamber and incorporating a high level sensing switch 15 electrically connected to the actuating means 17, whereby lqiuid rising to a predetermined height in the pipe, due to clogging of the filter bed 5, and contacting the switch, causes the valve to open thereby initiating the backwash cycle, and a low level sensing switch 19, having a probe 20 disposed in the compartment 11, which is electrically connected to the actuating means 17, whereby liquid in the compartment falling below a predetermined level excites the switch 19 thereby causing the valve to close and end the backwash cycle. Scrubbing of the backwashing storage compartment may be assisted by the introduction of compressed air into the compartment. An underdrain compartment 9 is situated below a false bottom 3 of the tank which is fitted with strainers 4. Reference is made to a filter tank having two or more filter chambers, such that one filter bed can be backwashed while the other chambers are being used for filtering in which event the continuing flow of filtered water from the latter chambers assists in the backwashing of the chamber being cleaned. The invention is applicable to water filtration. |
