Pump control system

Abstract

A pump controller is disclosed for controlling a pump for a fluid medium such as water. The pump controller includes a metal substrate ( 11 ) adapted to have a first side thereof exposed to the fluid medium and an insulating medium applied to a second side of the substrate. A pressure sensing means ( 12 ) including at least one pressure responsive element (R 9 , R 10 ) is implemented on the insulating medium closely adjacent the substrate such that the pressure element is responsive to pressure of the fluid medium when the first side is exposed to the fluid medium. A flow sensing means ( 13 ) including at least one source of heat ( 15 ) and at least one temperature responsive element ( 16 ) is implemented on the insulating medium closely adjacent the substrate, such that the temperature responsive element is responsive to flow of the fluid medium when the first side is exposed to the flow, with the fluid medium providing a sink for the source of heat in a manner that is related to the flow. The pump controller includes switching means ( 17 ) for switching the pump on or off and a processing means ( 14 ) for receiving data from the pressure sensing means and the flow sensing means. The data is communicated via conductive tracks implemented on the insulating medium. The processing means is adapted to process the data and to produce an output for driving the switching means. A housing for a sensor substrate having a wet side and a dry side and adapted to promote contact of the wet side with the pumped fluid medium and to substantially prevent contact of the dry side with the fluid medium is also disclosed.

1 . A pump controller for controlling a pump for a fluid medium such as water, said pump controller including: 
 a metal substrate adapted to have a first side thereof exposed to said fluid medium;    an insulating medium applied to a second side of said substrate;    pressure sensing means including at least one pressure responsive element implemented on said insulating medium closely adjacent said substrate such that said pressure element is responsive to pressure of said fluid medium when said first side is exposed to said fluid medium;    flow sensing means including at least one source of heat and at least one temperature responsive element implemented on said insulating medium closely adjacent said substrate, such that said temperature responsive element is responsive to flow of said fluid medium when said first side is exposed to said flow, said fluid medium providing a sink for said source of heat in a manner that is related to said flow;    switching means for switching said pump on or off; and    processing means for receiving data from said pressure sensing means and said flow sensing means, said data being communicated via conductive tracks implemented on said insulating medium, said processing means being adapted for processing said data and for producing an output for driving said switching means.    
     
     
         2 . A pump controller according to  claim 1  wherein said metal substrate includes titanium.  
     
     
         3 . A pump controller according to  claim 1  wherein said metal substrate includes low carbon stainless steel.  
     
     
         4 . A pump controller according to  claim 1 , wherein said insulating medium includes a ceramic.  
     
     
         5 . A pump controller according to  claim 1  wherein said pressure responsive element includes a plurality of resistors formed by conductive tracks on said insulating medium, said resistors being arranged such that pressure on said substrate is measured by a change in value due to tension on said resistors.  
     
     
         6 . A pump controller according to  claim 1  wherein said temperature responsive element includes an operational amplifier and a bridge circuit containing a plurality of thermisters.  
     
     
         7 . A pump controller according to  claim 1  wherein said switching means includes a triac.  
     
     
         8 . A pump controller according to  claim 7  wherein said triac is mounted on said substrate to provide said source of heat.  
     
     
         9 . A pump controller according to  claim 1  wherein said at least one temperature responsive element includes a temperature sensor on each side of said metal substrate for detecting a temperature difference between said first and second sides.  
     
     
         10 . A pump controller according to  claim 9  wherein said processing means is adapted to compensate for anomalies caused by said temperature difference.  
     
     
         11 . A pump controller according to  claim 1  wherein said processing means includes a microprocessor or microcontroller.  
     
     
         12 . A housing for a sensor substrate having a wet side and a dry side and adapted to promote contact of said wet side with a fluid medium and to substantially prevent contact of said dry side with said fluid medium, said housing including: 
 a main body having an opening for said fluid medium and for receiving said sensor substrate with its wet side exposed to said opening;    a first chamber maintained substantially at atmospheric pressure;    first sealing means arranged between said opening and said sensor substrate such that a leak path is provided to said first chamber;    a closure for said housing including a second chamber exposed to said dry side of said sensor substrate; and    second sealing means arranged between said closure and said first chamber to substantially prevent ingress of said fluid medium to said second chamber.    
     
     
         13 . A housing according to  claim 12  wherein said first sealing means includes a peripheral bead interposed between said wet side of said sensor substrate and an inner edge of said opening.  
     
     
         14 . A housing according to  claim 12  wherein said second sealing means includes a peripheral bead interposed between an edge associated with said first chamber and said closure.  
     
     
         15 . A housing according to  claim 12  wherein said first and second sealing means are connected by a membrane, said membrane providing an additional barrier to moisture reaching said dry side of said sensor substrate.  
     
     
         16 . A housing according to  claim 15  wherein said membrane includes a recess for receiving a peripheral edge of said sensor substrate.  
     
     
         17 . A housing according to  claim 12  wherein said first and second sealing means are formed from an elastomeric material.  
     
     
         18 . A housing according to  claim 12  wherein said membrane is formed from an elastomeric material.  
     
     
         19 . A housing according to  claim 12  including a venturi device adapted to accelerate flow of pumped fluid in the vicinity of said opening.  
     
     
         20 . A pump controller adapted for controlling a pump for a fluid medium substantially as herein described with reference to FIGS.  1  to  3  of the accompanying drawings.  
     
     
         21 . A housing for a sensor substrate substantially as herein described with reference to FIGS.  4  to  12  of the accompanying drawings.