Hydraulic diaphragm control

Abstract

A diaphragm pump includes a pumping chamber for pumped fluid and a hydraulic chamber. A diaphragm has a pumping chamber side and a hydraulic chamber side. The pumping chamber side of the diaphragm is proximate the pumping chamber and acts on the pumped fluid. The hydraulic chamber side of the diaphragm is proximate the hydraulic chamber. A plunger is in fluid communication with the hydraulic chamber and acts on the hydraulic fluid, which acts on the diaphragm. A plunger driver imparts reciprocal motion to the plunger. The pump includes a sensor assembly sensing position and direction of the plunger and sensing position of the diaphragm. By sensing the position of the diaphragm, hydraulic fluid flow is controlled by a control single valve.

What is claimed is: 
     
         1 . A diaphragm pump comprising:
 a pumping chamber;   a hydraulic chamber;   a diaphragm having a pumping chamber side and a hydraulic chamber side, the pumping chamber side being proximate the pumping chamber and the hydraulic chamber side being proximate the hydraulic chamber;   a plunger in fluid communication with the hydraulic chamber;   a plunger driver imparting reciprocal motion to the plunger;   a sensor assembly sensing position and direction of the plunger and sensing position of the diaphragm.   
     
     
         2 . The diaphragm pump according to  claim 1 , further comprising a valve in fluid communication with the hydraulic chamber. 
     
     
         3 . The diaphragm pump according to  claim 2 , wherein the plunger driver comprises a stepper motor. 
     
     
         4 . The diaphragm pump according to  claim 3 , further comprising a controller in communication with the sensor assembly, the stepper motor and the valve, wherein the sensor assembly. 
     
     
         5 . The diaphragm pump according to  claim 1 , wherein the plunger drive comprises a crankshaft and wherein the sensor assembly comprises a first crankshaft sensor sensing position of the crankshaft. 
     
     
         6 . The diaphragm pump according to  claim 1 , wherein the diaphragm comprises a diaphragm rod extending from the hydraulic chamber side and wherein the sensor assembly comprises a sensor sensing a position of the diaphragm rod 
     
     
         7 . The diaphragm pump according to  claim 1 , wherein the diaphragm comprises a diaphragm rod extending from the hydraulic chamber side and wherein the sensor assembly comprises a first sensor and a second sensor spaced apart from the first sensor, the first sensor and the second sensor sensing a position of the diaphragm rod. 
     
     
         8 . The diaphragm pump according to  claim 1 , wherein the diaphragm comprises a diaphragm rod extending from the hydraulic chamber side and wherein the sensor assembly comprises a linear variable differential transformer (LVDT) sensing a position of the diaphragm rod. 
     
     
         9 . The diaphragm pump according to  claim 1 , wherein the plunger drive comprises a crankshaft and wherein the sensor assembly comprises a first crankshaft sensor sensing position of the crankshaft and a second crankshaft sensor sensing the position of the crankshaft. 
     
     
         10 . A diaphragm pump sensing and control system, the diaphragm pump comprising a diaphragm, a hydraulic fluid chamber and a plunger acting on the hydraulic fluid chamber; the diaphragm pump sensing system comprising:
 a first sensor sensing position and direction of the plunger; and   a second sensor sensing position of the diaphragm;   a single valve controlling fluid flow into and out of the hydraulic fluid chamber.   
     
     
         11 . A method for controlling a diaphragm pump, the diaphragm pump comprising
 a diaphragm, a fluid chamber containing hydraulic fluid acting on the diaphragm, a plunger in fluid communication with the fluid chamber, and a single valve controlling flow into and out of the fluid chamber, the method comprising:
 sensing position and direction of the plunger; 
 sensing position and direction of movement of the diaphragm;