Hydraulic fluid control system for a diaphragm pump

A hydraulic fluid control system for a hydraulic diaphragm pump comprising a first diaphragm containing a process fluid and which is surrounded by a first hydraulic fluid chamber containing a hydraulic fluid, wherein said hydraulic fluid control system comprises:

• a hydraulic fluid drive source that is fluidly connected to the first hydraulic fluid chamber and operable to displace hydraulic fluid into and out of the first hydraulic fluid chamber;
• a first single sensor in fluid communication with both the hydraulic fluid contained within the first hydraulic fluid chamber and the process fluid contained within the diaphragm, the first single sensor operable to detect and measure a pressure differential between the process fluid contained in the first diaphragm and said hydraulic fluid contained in the first hydraulic fluid chamber;
• a hydraulic fluid reservoir containing hydraulic fluid;
• and
• a first hydraulic fluid supply pump fluidly connected to said hydraulic fluid reservoir and the first hydraulic fluid chamber, the first hydraulic fluid supply pump configured as a bidirectional pump operable to add a volume of said hydraulic fluid from the reservoir to the first hydraulic fluid chamber or remove a volume of said hydraulic fluid from the first hydraulic fluid chamber to the reservoir in response to said pressure differential measured by the first single sensor.