Apparatus for sensing fluid flow and associated load control circuit

Abstract

A circuit and apparatus for magnetically sensing fluid flow and applying voltage to a load has a spring loaded check valve disposed within a conduit and provided with a magnetic shield. A magnet is located on one side of the magnetic shield while a sensor, associated with the valve, is located on the opposite side of the magnetic shield. The check valve, and hence the magnetic shield, moves to permit fluid flow. When the magnetic shield moves due to fluid flow, the magnet activates the sensor. A load control circuit includes a supply terminal for receiving a supply voltage and a detector which detects a condition requiring the operation of a load. The detector causes a threshold voltage to be generated from the supply voltage, and a time delay controller controls the time required to generate the threshold voltage. A DIAC or equivalent element conducts to generate a first trigger signal once the threshold voltage is achieved, and a silicon-controlled rectifier (SCR) generates a second trigger signal in response to the first trigger signal. The circuit includes an opto-TRIAC and triac which are rendered conductive by the second trigger signal to cause a voltage to be provided to the load.

What is cladmed is:  
     
         1 . A spring loaded check valve comprising: 
 an inlet;    an outlet;    spring loaded valve member means which prevents passage of fluid from the inlet to the outlet in a closed position, and which allows passage of fluid from the inlet to the outlet in an open position; and    magnetic switch means associated with the spring loaded valve member means for sensing a position of the spring loaded valve member means.    
     
     
         2 . The spring loaded check valve of    claim 1   , wherein said magnetic switch means further comprises: 
 magnetic shield means attached to the spring loaded valve member means for movement therewith between the open position and closed position; and    circuit means to sense the magnetic shield means, whereby the position of the spring loaded valve member means may be determined.    
     
     
         3 . The spring loaded check valve of    claim 2   , wherein the circuit means includes a Hall Effect sensor located in close proximity to a magnet.  
     
     
         4 . The spring loaded check valve of    claim 3   , wherein the Hall Effect sensor is activated by the magnet, and wherein the magnetic shield means blocks the Hall Effect sensor from being activated when the spring loaded valve member means is in the closed position.  
     
     
         5 . The spring loaded check valve of    claim 1   , further comprising a valve seat and wherein the spring loaded valve member means includes a member which is positioned against the valve seat when said spring loaded valve member means is in said closed position.  
     
     
         6 . The spring loaded check valve of    claim 2   , wherein the circuit means further comprises a reed switch located in close proximity to a magnet.  
     
     
         7 . The spring loaded check valve of    claim 6   , wherein the reed switch is activated by the magnet, wherein the magnetic shield means prevents the reed switch from being activated when the spring loaded valve member means is in the closed position, and wherein the magnetic shield means does not prevent the reed switch from activating when the spring loaded check valve member means is in the open position.  
     
     
         8 . The spring loaded check valve of    claim 3   , wherein the Hall Effect sensor is provided in a casing located within the spring loaded check valve.  
     
     
         9 . The spring loaded check valve of    claim 8   , wherein the casing is provided with -threads to cooperate with a threaded hole in a wall of the spring loaded check valve.  
     
     
         10 . The spring loaded check valve of    claim 4   , further comprising alarm means for sounding an alarm in response to current provided by the Hall Effect sensor, when activated.  
     
     
         11 . The spring loaded check valve of    claim 4   , wherein the circuit means includes a time delay circuit for delaying the supply of current to a load.  
     
     
         12 . The spring loaded check valve of    claim 6   , wherein the reed switch is provided in a casing located within the spring loaded check valve.  
     
     
         13 . The spring loaded check valve of    claim 12   , wherein the casing is provided with threads to cooperate with a threaded hole in a wall of the spring loaded check valve.  
     
     
         14 . A fluid flow alarm system, comprising: 
 a spring loaded check valve comprising an inlet and an outlet, spring loaded valve member means which prevents passage of fluid from the inlet to the outlet of the spring loaded check valve in a closed position, and which allows passage of fluid from the inlet to the outlet of the spring loaded check valve in an open position, magnetic switch means associated with the spring loaded valve member means for sensing the position of the spring loaded valve member means, said magnetic switch means further comprising:    magnetic shield means attached to the spring loaded valve member means for movement therewith between the open position and closed position; and    circuit means to sense the position of the magnetic shield means, whereby the position of the spring loaded valve member means may be determined, the circuit means further including:    first voltage supply means;    first trigger means that detects activation of a sensor when the spring loaded valve member means is in an open position and generates a first trigger signal;    time controller means for adjustably controlling the time required to generate the first trigger signal;    second trigger means that generates a second trigger signal in response to said first trigger signal; and    switch means for providing a load voltage to an alarm in response to said second trigger signal.    
     
     
         15 . The system of    claim 14   , wherein said spring loaded check valve member means can be manually placed into the closed position and wherein the spring loaded check valve member means is situated against a valve seat when the spring loaded check valve member is in the closed position.  
     
     
         16 . The fluid flow alarm system of    claim 14   , wherein said time controller means comprises a dip switch.  
     
     
         17 . The fluid flow alarm system of    claim 16   , wherein the time required to generate the first trigger signal is adjustable from 0 to 90 seconds.  
     
     
         18 . The fluid flow alarm system of    claim 14   , wherein the circuit means comprises an A.C. power source and back-up battery.  
     
     
         19 . The fluid flow alarm system of    claim 14   , wherein the circuit means comprises a battery.