Fluid control apparatus and method

Abstract

The invention provides control apparatus for use with a fluid displacement device, for example a compressor, the control apparatus comprising means ( 24 ) to detect the temperature of fluid being displaced by the device and means ( 11 ) to control the device independence upon the sensor temperature. Preferably there is also means ( 22 ) to sense the pressure of the fluid being displaced by the device, a combination of temperature signals and pressure signals being utilised to control the device. The invention enables very sophisticated monitoring and control to be carried out, for example utilising pre-selected temperature and pressure bands.

1 . Control apparatus for use with a fluid displacement device, the control apparatus comprising means to detect the temperature of fluid being displaced by the device, and means to control the device in dependence upon the sensed temperature.  
     
     
         2 . Control apparatus as claimed in  claim 1 , in which there is also means to sense the pressure of the fluid being displaced by the device, a combination of temperature signals and pressure signals being utilised to control the device.  
     
     
         3 . Control apparatus as claimed in  claim 2 , having means to preset at least one temperature control limit such that if fluid temperature rises above this limit, the apparatus operates to lower the working pressure.  
     
     
         4 . Control apparatus as claimed in  claim 3 , in which there is a temperature control band extending between preset limits.  
     
     
         5 . Control apparatus as claimed in  claim 4 , in which the control apparatus is such that, once the temperature has dropped below a preset limit, the control apparatus continues to monitor the temperature for a predetermined period before increasing the working pressure again.  
     
     
         6 . Control apparatus as claimed in any one of  claims 2  to  5 , having means to preset at least one pressure limit, the control apparatus being arranged to drop the pressure if the pressure rises above this limit.  
     
     
         7 . Control apparatus as claimed in  claim 7 , in which there is a pressure control band extending between preset limits.  
     
     
         8 . Control apparatus as claimed in any one of  claims 2  to  7 , arranged to monitor pressure for a predetermined period.  
     
     
         9 . Control apparatus as claimed in any one of the preceding claims, arranged to monitor the torque associated with a device being controlled by the apparatus.  
     
     
         10 . Control apparatus as claimed in any one of the preceding claims, also arranged to monitor the speed associated with a device being controlled by the apparatus.  
     
     
         11 . Control apparatus as claimed in any one of the preceding claims, in which the fluid displacement device is a compressor.  
     
     
         12 . Control apparatus as claimed in any one of  claims 1  to  10 , in which the fluid displacement device is a pump.  
     
     
         13 . Control apparatus as claimed in any one of  claims 1  to  10 , in which the fluid displacement device is a blower.  
     
     
         14 . Control apparatus as claimed in any one of the preceding claims, having a pressure relief valve movable between a closed position in which pressure is contained, and a relief position in which fluid can vent to reduce pressure.  
     
     
         15 . Control apparatus as claimed in  claim 14 , in which the pressure relief valve is solenoid operated.  
     
     
         16 . Control apparatus as claimed in any one of the preceding claims, having means to receive an electric power supply, for example from a tanker vehicle.  
     
     
         17 . Control apparatus as claimed in  claim 16 , in which the power supply is from 24 to 30 V DC.  
     
     
         18 . Control apparatus as claimed in any one of the preceding claims, having means to receive an air supply, for example from a tanker vehicle.  
     
     
         19 . Control apparatus as claimed in  claim 18 , in which the air is supplied at from 6 to 8 bar.  
     
     
         20 . Control apparatus as claimed in any one of the preceding claims, having means to receive a temperature signal and a pressure signal.  
     
     
         21 . Control apparatus as claimed in any one of the preceding claims, having a conduit to supply control air from an air supply to a pressure relief valve, under the control of a solenoid.  
     
     
         22 . Control apparatus constructed and arranged substantially as herein described, with reference to the accompanying drawings.  
     
     
         23 . A displacement device having control apparatus as claimed in any one of the preceding claims.  
     
     
         24 . A tanker vehicle having control apparatus as claimed in any one of  claims 1  to  22 .  
     
     
         25 . A method of controlling the pressure of a fluid comprising detecting the temperature of the fluid and controlling the pressure of the fluid in dependence upon a sensed temperature.  
     
     
         26 . A method as claimed in  claim 25 , in which the pressure of the fluid is also sensed, a combination of temperature signals and pressure signals being utilised for control purposes.  
     
     
         27 . A method of controlling the pressure of a fluid, substantially as herein described with reference to the accompanying drawings.