Multistage power saving vacuum device with root vacuum pump in first stage

Abstract

A multistage power saving vacuum device with a root vacuum pump in a first stage comprises a vacuum inlet gas-driving shut-off valve for receiving non-condensing gas pumping from a power plant condenser; a first root vacuum pump connected to the vacuum inlet gas-driving shut-off valve for receiving and compressing the gas outputted from the vacuum inlet gas-driving shut-off valve; a second vacuum pump serially connected to the first root vacuum pump for further compressing the gas from the first root vacuum pump. A last stage vacuum pump connected to the second vacuum pump for further compressing the gas outputted from the second vacuum pump; and a vapor separator connected to the last stage vacuum pump for separating vapor and air; wherein the gas is vented out and the vapor is returned to the last stage vacuum pump.

What is claimed is: 
     
         1 . A multistage power saving vacuum device with a root vacuum pump in a first stage, comprising:
 a vacuum inlet gas-driving shut-off valve ( 13 ) for receiving non-condensing gas pumping from a power plant condenser;   a first root vacuum pump ( 1 ) connected to the vacuum inlet gas-driving shut-off valve for receiving and compressing the gas outputted from the vacuum inlet gas-driving shut-off valve;   a second vacuum pump ( 2 ) serially connected to the first root vacuum pump for further compressing the gas from the first root vacuum pump ( 1 ); and when there are more than one second vacuum pumps ( 50 ), all the second vacuum pumps being serially connected.   
     
     
         2 . The vacuum device of  claim 1 , further comprising:
 a last stage vacuum pump ( 3 ) connected to the second vacuum pump ( 2 ) for further compressing the gas outputted from the second vacuum pump ( 2 ); and   a vapor separator ( 10 ) connected to the last stage vacuum pump ( 3 ) for separating vapor and air; wherein the gas is vented out and the vapor is returned to the last stage vacuum pump ( 3 ).   
     
     
         3 . The vacuum device of  claim 1 , wherein the second vacuum pump is a root vacuum pump. 
     
     
         4 . The vacuum device of  claim 1 , wherein a gas valve of each vacuum pump is automatically and intellectually controlled. 
     
     
         5 . The vacuum device of  claim 1 , wherein a second gas-driving device ( 19 ) serves for driving gas within the second vacuum tube ( 200 ); the second gas-driving device ( 19 ) includes a second frequency adjustable motor ( 191 ); the second frequency adjustable motor ( 191 ) is at an outer side of the second vacuum tube ( 200 ). 
     
     
         6 . The multistage power saving vacuum device of  claim 1 , wherein pressures measured by a pressure sensor ( 11 ) at the inlet of the first root vacuum pump ( 1 ), pressures of the input end of the pre driving two-stage circulated pump ( 3 ) which are measured by a pressure sensor ( 12 ) at the output end of the at least one second vacuum pump, temperatures measured by a temperature sensor ( 15 ) in the first root vacuum pump ( 1 ) and a temperature sensor ( 16 ) in the at least one second vacuum pump ( 2 ) are analyzed; and then signals from the analysis are transferred to a first frequency adjustable motor ( 181 ) of the first root vacuum pump ( 1 ) and a second frequency adjustable motor ( 191 ) of the first one second vacuum pump ( 2 ) so as to adjust rotation speeds of the first frequency adjustable motor ( 181 ) and the second frequency adjustable motor ( 191 ) so that the whole system has an optimum and safe operation. 
     
     
         7 . The vacuum device of  claim 1 , wherein the second vacuum pump ( 50 ) further comprises a second vacuum tube ( 200 ); the system can open or close an gas-driving valve ( 171 ) of the bypass pressure difference adjusting tube ( 17 ) of the second root vacuum pump ( 2 ) so as to adjust the pressure difference within the vacuum tube ( 200 ).