Metering Check Valve for Fluid Injection

Abstract

A flow meter check valve is described. The flow meter check valve can be connected to the discharge side of a reciprocating action fluid pump to monitor, analyze, calculate and be used to control the flow of liquid through the pump. Embodiments of the flow meter check valve combine aspects of a backflow check valve with the metering capability of a rotameter variable area flow device. The flow meter check valve features a tapered tube and a float. The position of the float within the tube is proportional to the forward fluid flow rate. A valve stem with a marker is attached to the float so that it moves in a direct linear motion proportional to the volume of fluid delivered. The position of the marker is detected by an external sensing mechanism.

What is claimed is: 
     
         1 . A valve configured to measure a volume of fluid delivered from a pump, wherein the pump comprises a piston, the valve comprising:
 an inlet configured to receive fluid from the pump,   a valve body,   a float configured to isolate the inlet from the valve body during a suction stroke of the piston and to open during a delivery stroke of the piston to allow fluid to flow through the valve body, and   a transducer configured to measure a distance the float travels as the fluid flows through the valve body, wherein the distance is indicative of a volume of fluid flowing through the valve.   
     
     
         2 . The valve of  claim 1 , further comprising a connection configured to connect the valve body to the pump. 
     
     
         3 . The valve of  claim 1 , wherein the float comprises a valve plug and a stem. 
     
     
         4 . The valve of  claim 3 , wherein the valve body comprises a plug seat, and wherein the valve plug is configured to form a sealing engagement with the plug seat during the suction stroke of the piston. 
     
     
         5 . The valve of  claim 3 , wherein the valve body comprises a sleeve comprising an inner wall conical section. 
     
     
         6 . The valve of  claim 5 , wherein the valve plug travels within the inner wall conical section as fluid flows through the valve body. 
     
     
         7 . The valve of  claim 6 , configured such that travel of the valve plug within the conical section creates a variable area orifice for flow of fluid through the valve body. 
     
     
         8 . The valve of  claim 3 , wherein the stem comprises a magnetic material on at least a portion of the stem. 
     
     
         9 . The valve of  claim 8 , wherein the transducer comprises at least one coil. 
     
     
         10 . The valve of  claim 9 , wherein the at least one coil comprises a generator coil configured to generate an electromagnetic field within the valve. 
     
     
         11 . The valve of  claim 10 , wherein the valve is configured so that as the float moves, the magnetic material creates a time-varying change in the electromagnetic field. 
     
     
         12 . The valve of  claim 11 , wherein the transducer further comprises a sense coil configured so that the time-varying change induces a current in the sense coil. 
     
     
         13 . The valve of  claim 12 , wherein the current in the sense coil is indicative of the volume of fluid delivered from a pump. 
     
     
         14 . The valve of  claim 8 , wherein the transducer comprises a Hall effect sensor or a linear variable differential transformer (LVDT). 
     
     
         15 . A system for measuring a volume of fluid delivered from a pump, wherein the pump comprises a piston, the system comprising:
 a valve comprising:   an inlet configured to receive fluid from the pump,   a valve body,   a float configured to isolate the inlet from the valve body during a suction stroke of the piston and to open during a delivery stroke of the piston to allow fluid to flow through the valve body, and   a transducer configured to measure a distance the float travels as the fluid flows through the valve body, wherein the distance is indicative of a volume of fluid flowing through the valve, and   control circuitry configured to receive data from the transducer and determine the volume of fluid delivered by the pump based on the data.   
     
     
         16 . The system of  claim 15 , wherein determining the volume of fluid comprises determining a data set indicative of the travel of the float as a function of time. 
     
     
         17 . The system of  claim 16 , wherein determining the volume of fluid further comprises integrating the data set. 
     
     
         18 . The system of  claim 15 , wherein the control circuitry is configured to use the data from the transducer to monitor for a fault. 
     
     
         19 . The system of  claim 18 ,
 wherein the float comprises a valve plug and a stem, and the valve body comprises a plug seat,   wherein the float is configured to obtain a rest position during the suction stroke of the pump such that the valve plug forms a sealing engagement with the plug, and   wherein monitoring for a fault comprises determining if the float returns to the rest position during the suction stroke.   
     
     
         20 . The system of  claim 19 , wherein the control circuitry is configured to issue an alarm signal if the float fails to return to the rest position by an amount exceeding a predetermined threshold value.