Liquid pressure reducing valve

A fluid pressure reducing valve apparatus comprising:

• a spring loaded pressure reducing valve having:
• a body having an interior void partitioned by a diaphragm into a fluid-flow chamber on one side of the diaphragm and a dry chamber on the other side of the diaphragm,
• a fluid supply orifice into the fluid-flow chamber and a fluid outlet from the fluid-flow chamber,
• a regulation plate selectively closing the orifice and subject in use to supply fluid acting on it, the regulation plate being connected directly or via a connecting element to the said one side of the diaphragm, and the diaphragm in use being subject in use to regulated pressure in the fluid-flow chamber,
• a compression spring located in the dry chamber on the said other side of the diaphragm, the compression spring being arranged so as to apply pressure through the diaphragm to urge the plate towards the orifice and
• a controllable motor drive acting between the body and an end of the compression spring remote from the regulation plate,
• a flow meter;
• a controller and an electronic data store held within or being in communication with the controller, the data store containing data defining a relationship between fluid flow rate and fluid pressure in a downstream pipe network to which the pressure reducing valve is connected;
• the controller being arranged to receive flow data from the flow meter and to control the motor drive for withdrawal or advancement of the remote end of the spring in accordance with the flow rate measured by the flow meter and the relationship between fluid flow and fluid pressure thereby to vary the position of the regulator plate and fluid flow through the fluid supply orifice to maintain a desired downstream fluid pressure.