Gas-cleaning apparatus

Claim 2

A gas-cleaning system which comprises a venturi scrubber means; a powered, variable speed fan means flow connected in series with said venturi scrubber means and operable to induce a flow of gases therethrough for cleansing thereby, said fan means having an inlet, and an outlet disposed for communication with a gas-receiving means to deliver cleansed gases thereto; a power sensor connected to said fan means to sense the operating power level thereof and establish a signal representing such power level; a pressure sensor disposed to sense the gas pressure at the inlet of said fan means and establish a signal representing such gas pressure; an adjustable damper disposed in the outlet of said fan means to regulate the resistance to the flow of gases therethrough; and means for maintaining a constant pressure drop across said venturi scrubber means including control means connected to said damper and fan means, and connected to said pressure and power sensors for operation in response to the signals thereof to adjust the speed of said fan means and the position of said damper in accordance with said signals to maintain a constant static gas pressure at the inlet of said fan means and to concurrently maintain a constant fan means operating power level.

Claim 3

The gas-cleaning apparatus according to claim 1 wherein said control means includes means defining two closed-loop feedback control systems, one of said control systems including the pressure sensor being operable to maintain a constant static gas pressure at the fan means inlet, and the other of said control systems, including the power sensor being operable to maintain a constant fan means operating power level.

Claim 4

The gas-cleaning apparatus according to claim 2 wherein the fan means inlet pressure control system receives the gas pressure signal of said pressure sensor and operates to vary the position of said damper in accordance with said gas pressure signal, and the fan means power control system receives the power level signal of said power sensor and operates to vary the speed of the fan means in accordance with said power level signal.

Claim 5

The gas cleaning apparatus according to claim 2 wherein the fan means inlet pressure control system receives the gas pressure signal of said pressure sensor and operates to vary the speed of the fan means in accordance with said gas pressure signal, and the fan means power control system receives the power level signal of said power sensor and operates to vary the position of said damper in accordance with said power level signal.

Claim 6

The gas-cleaning apparatus according to claim 2 wherein said fan means includes a rotary fan, a motor, and a variable speed ratio transmission coupled to said motor and to said fan for driving same by said motor, said transmission having speed ratio adjustment means disposed to receive an external input for seLectively varying the ratio between the speed of said motor and the speed of said fan; and wherein said fan means inlet pressure control system includes a pressure error detector connected to said pressure sensor to receive the gas pressure signal thereof and disposed to receive an input representing a reference constant static gas pressure to be maintained at the fan means inlet, said pressure error detector being responsive to said gas pressure signal and to said reference pressure input to establish a pressure error signal representing the difference between said reference static gas pressure and the static gas pressure existing at said inlet as indicated by the signal of said pressure sensor, and a pressure error signal processor connected to said pressure error detector to receive the pressure error signal thereof, and responsive to said pressure error signal to establish an output signal representing a predetermined function of the pressure error as indicated by said pressure error signal; and wherein said fan means power control system includes a power error detector connected to said power sensor to receive the fan means power level signal thereof and disposed to receive an input representing a reference constant fan means power level to be maintained, said power error detector being responsive to said power level signal and to said reference power level input to establish a power error signal representing the difference between said reference power level and the existing power level of the fan means as indicated by the signal of said power sensor, and a power error signal processor connected to said power error detector to receive the power error signal thereof and responsive to said power error signal to establish an output signal representing a predetermined function of the power error as indicated by said power error signal.

Claim 7

The gas-cleaning apparatus according to claim 5 wherein said fan means inlet pressure control system includes an actuator connected to said pressure error signal processor to receive the output signal thereof and connected to said damper to adjust the position thereof in accordance with said output signal to null the pressure error, and said fan means power control system includes a speed ratio changer means connected to said power error signal processor to receive the output signal thereof and connected to the speed ratio adjustment means of said transmission to adjust the speed ratio thereof in accordance with said output signal and thereby regulate the speed of the fan means to null the power error.

Claim 8

The gas-cleaning apparatus according to claim 5 wherein said fan means inlet pressure control system includes a speed ratio changer means connected to said pressure error signal processor to receive the output signal thereof and connected to the speed ratio adjustment means of said transmission to adjust the speed ratio thereof in accordance with said output signal and thereby regulate the speed of the fan means to null the pressure error, and said fan means power control system includes an actuator connected to said power error signal processor to receive the output signal thereof and connected to said damper to adjust the position thereof in accordance with said output signal to null the power error.

Claim 9

The gas-cleaning apparatus according to claim 5 wherein said pressure error signal processor produces an output signal which corresponds to a proportional plus integral function of the pressure error.

Claim 10

The gas-cleaning apparatus according to claim 5 wherein said power error signal processor produces an output signal which corresponds to a proportional plus integral function of the power error.

Claim 11

The gas-cleaning apparatus according to claim 5 wherein said pressure error signal processor produces an output signal which corresponds to a proportional plus integral function of the pressure error, and said power error signal processor produces an output signal which corresponds to a proportional plus integral function of the poweR error.