| 摘要 |
PURPOSE:To control automatically and appropriately the backwashing cycle by increasing and decreasing the backwashing cycle on the basis of the signals from a differential pressure detector and a flow rate detector, and setting the backwashing cycle in the backwashing cycle controlling mechanism for a bag filter. CONSTITUTION:Although the backwashing cycle of a bag filter 10 is controlled by the output signal from a control unit 30 during the stationary operation, the pressure drop before the backwashing and after the backwashing 1 cycle is sent out from a differential pressure detector 22 into an arithmetic unit, and the difference DELTAdP(n) between both differential pressures is calculated and stored in a storage 24. The DELTAdP(n+1) of the succeeding backwashing cycle is likewise obtained, and the difference between the two pressure drops are compared to increase and decrease the backwashing cycle T. The output signal of a flow rate detector 18 is inputted to a backwashing cycle setting unit 26 wherein the signal is coupled with the signal obtained by the comparison of DELTAdP(n) with DELTAdP(n+1). The coupled signal is inputted to the control unit 30 to automatically control the backwashing cycle T.
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