Injection pump apparatus

Abstract

A pump monitoring and flow control system that provides direct indication and control of discharge flow on gas driven positive displacement or diaphragm injection-type pumps. The device uses a “tell-tale” check valve that drives a proximity switch each time the tell-tale valve, installed as the output check valve on a standard injection pump, opens with discharge flow. The proximity switch in turn signals the monitoring system which computes the volume of chemical injected and controls the injection pump gas motor to provide the required volume of injected fluid. Additionally the system can alarm if injection flow is interrupted.

1 . An improved pneumatic motor for operating an injection pump of the type having a cylinder incorporating a moveable piston having two sides one side being connected to the injection pump and being biased towards one end of the cylinder and having a pressure regulator means and venting means incorporated within the cylinder and operated by the movement of the piston, and wherein the injection pump has an outlet check valve, wherein the improvement comprises:
 (a) elimination of the venting means incorporated within the cylinder;   (b) replacement of the pressure regulator means with a 3-way electric solenoid valve, wherein said 3-way electric solenoid valve shifts to apply pressure to the non-biased side of the moveable piston or vents pressure from the non-biased side of the moveable piston;   (c) replacement of the outlet check valve with an indicating check valve incorporating means to indicate the open or closed position of said indicating check valve; and   (d) electronic control means for sensing said open position of said indicating check valve and for modulating said 3-way electric solenoid between applying pressure to or venting pressure from the non-biased side of the moveable piston dependent on a control algorithm internally stored in said electronic controller.   
   
   
       2 . The improvement of  claim 1 , wherein the injection pump is connected to a process stream to which fluids are to be injected in a given ratio, and wherein said electronic control means accepts a setpoint indicative of the required given ratio and wherein said algorithm computes the required quantity of injected fluid per unit time and modulates said 3-way electric solenoid valve while sensing said open position of said indicating check valve thereby providing the correct quantity of injection fluid. 
   
   
       3 . The improvement of  claim 2 , wherein the process stream quantity of flow is measured and provided to said electronic control means and wherein said algorithm modulates said 3-way solenoid valve thereby varying the injection fluid quantity proportionally to the process stream quantity thereby providing a given ratio of injection fluid to process stream fluid. 
   
   
       4 . An apparatus and control system for injecting a given quantity of injection fluid into a stream containing a process fluid comprising:
 (a) an injection pump having an inlet and outlet port;   (b) an indicating check valve connected to said outlet port, and wherein said inlet port is connected to a source of injection fluid and wherein said indicating check valve is in communication with the stream containing a process fluid and wherein said indicating check valve provides indication of the open or closed position thereof;   (c) a cylinder means incorporating a moveable piston having a first side and a second side, wherein said first side is larger in area than said second side, said piston having means mechanically coupling said piston to said injection pump;   (d) means for biasing said piston on said second side of said piston;   (e) means for supplying and venting pneumatic fluid under pressure to said first side of said piston;   (f) control means for operating said means for supplying and venting pneumatic fluid under pressure wherein said control means monitors said open position of said indicating check valve and operates said means for supplying and venting pneumatic pressure thereby operating said injection pump and causing the given quantity of injection fluid to enter the process stream.   
   
   
       5 . The apparatus of  claim 4  wherein a given ratio of injection fluid to process fluid is required and wherein said electronic control means accepts a setpoint indicative of the required ratio and wherein said algorithm computes the required quantity of injected fluid per unit time and modulates said 3-way electric solenoid valve while sensing said open position of said indicating check valve thereby providing the correct quantity of injection fluid in the required ratio. 
   
   
       6 . The apparatus of  claim 5 , wherein the process stream quantity of flow is measured and provided to said electronic control means and wherein said algorithm modulates said 3-way solenoid valve thereby varying the injection fluid quantity proportionally to the process stream quantity thereby providing a given ratio of injection fluid to process stream fluid. 
   
   
       7 . The improvement of  claim 1  wherein said electronic control means is incorporated into a SCADA system. 
   
   
       8 . The apparatus of  claim 5  wherein said electronic control means is incorporated into a SCADA system.