Vacuum management system

Abstract

The invention provides a flywheel system comprising a flywheel mounted for rotation within a chamber, a vacuum pump system and a valve for selectively closing a passage, wherein the chamber is coupled to an inlet of the vacuum pump system via the passage. The invention also provides a method of controlling the starting and stopping of the flywheel system.

We claim: 
     
         1 . A flywheel system comprising:
 a flywheel;   a chamber within which said flywheel is provided;   a passage for connecting the chamber to an inlet of a vacuum pump; and   a valve arranged to selectively open or close said passage, wherein the flywheel and the vacuum pump are mechanically coupled.   
     
     
         2 . A flywheel system according to  claim 1 , wherein the valve is adapted to open or close said passage based at least partially upon a chamber pressure value corresponding to the pressure in the chamber. 
     
     
         3 . A flywheel system according to  claim 2 , wherein the valve is arranged to open the passage when said chamber pressure value exceeds a first pressure value. 
     
     
         4 . A flywheel system according to  claim 3  wherein the first pressure value is between 4 and 8 mbar. 
     
     
         5 . A flywheel system according to  claim 2  further comprising a pressure sensor for determining said chamber pressure value. 
     
     
         6 . A flywheel system according to  claim 1  wherein the valve includes a sealing means for sealing the flow path through the passage and wherein the sealing means includes a face seal. 
     
     
         7 . A flywheel system according to  claim 1  further comprising a controller adapted to maintain the valve in a closed state until the flywheel is rotating, and open the valve after the flywheel begins rotating. 
     
     
         8 . A flywheel system according to  claim 1  further comprising a controller adapted to start the flywheel system, wherein the controller is further adapted to open the valve following start-up of the flywheel system, when the vacuum pump is rotating at a speed in excess of a speed threshold value. 
     
     
         9 . A flywheel system according to  claim 1  further comprising a controller adapted to determine when the rotating flywheel is to be shut down, and close the valve before controlling said flywheel to come to rest. 
     
     
         10 . A flywheel system according to  claim 1  further comprising a controller adapted to monitor the pump speed of said flywheel system, wherein the controller opens the valve when the pump speed is above a threshold value. 
     
     
         11 . A flywheel system according to  claim 1  further comprising a controller adapted to open the valve when a chamber pressure value corresponding to the pressure in the chamber is above a threshold value which is between 4 and 8 mbar. 
     
     
         12 . A flywheel system comprising:
 a flywheel;   a chamber within which said flywheel is provided;   a passage for connecting the chamber to an inlet of a vacuum pump   a valve arranged to selectively open or close said passage; and   a controller adapted to determine a chamber pressure value corresponding to the pressure in the chamber; determine a maximum allowable flywheel speed based on the determined chamber pressure value; and limit the speed of the flywheel based on the determined maximum allowable flywheel speed.   
     
     
         13 . A flywheel system according to  claim 12 , wherein the controller is further adapted to decrease the value of the determined maximum allowable flywheel speed with increasing pressure in the chamber. 
     
     
         14 . A method of controlling a flywheel system according to  claim 12 , wherein the determined maximum allowable flywheel speed value is less than 10,000 rpm when the chamber pressure value is above 10 mbar. 
     
     
         15 . A flywheel system comprising:
 a flywheel;   a chamber within which said flywheel is provided;   a passage for connecting the chamber to an inlet of a vacuum pump; and   a valve arranged to selectively open or close said passage, at least partially based upon a chamber pressure value corresponding to the pressure in the chamber, and wherein the valve is arranged to open the passage when said chamber pressure value exceeds a value that is between 4 and 8 mbar.   
     
     
         16 . A flywheel system according to  claim 15  further comprising a pressure sensor for determining said chamber pressure value. 
     
     
         17 . A flywheel system according to  claim 15  wherein the valve includes a seal for sealing the flow path through the passage and wherein the seal includes a face seal. 
     
     
         18 . A flywheel system according to  claim 15  further comprising a controller arranged to start the flywheel system, the controller adapted to maintain the valve in a closed state until the pump is rotating; and open the valve after the pump begins rotating. 
     
     
         19 . A flywheel system according to  claim 18  wherein the controller is further arranged to open the valve when the vacuum pump is rotating at a speed in excess of a speed threshold value. 
     
     
         20 . A flywheel system according to  claim 15  further comprising a controller arranged to shut down the flywheel system, the controller adapted to determine when the flywheel system is to be shut down, and close the valve before controlling the vacuum pump to come to rest.