for this purpose a conventional electric actuator 72 is connected to control valve 68 actuator 72 is connected by electrical line 76 to an amp controller 78 which is electrically connected by electrical line 82 to motor 24 this system could be pneumatically or otherwise operated instead of electrically in operation fig1 shows the system 20 at the time of start up when a new felt is introduced to the system to travel in the direction of the arrows at start up with the new felt control valve 68 is closed thereby closing the conduit pathway between suction pipe 50 and centrifugal exhauster 22 alternatively the valve 68 can be slightly open without materially affecting the operation of the system thus there is no air flow or virtually no air flow through the system as shown by the absence of arrows along conduit 66 on the other hand throttling valve 70 is fully open and air flow is drawn through slot 34 of suction pipe 30 into the hollow interior 32 of the pipe along with water removed from the felt passing over the slot this combination of air and water than passes through conduit 36 into separator 38 where the water is removed in conventional fashion and passes through drop leg 40 into reservoir 44 the air continues its travel through conduit 46 and conduit 48 into the centrifugal exhauster 22 and is exhausted therefrom to atmosphere this is shown by the arrows in fig1 as time passes in use of the felt and the felt permeability decreases the air flow to the exhauster 22 also decreases this results in lower drive horsepower since horsepower is.