Fluid Flow Control System

A fluid flow control system comprising:

• a heating device for heating a fluid;
• a first flow path for providing the heated fluid from the heating device to a use region;
• a heat exchanger having a supply path adapted to receive fluid from a fluid supply and a outlet path adapted to receive fluid from the use region, whereby the fluid in the supply path is pre-heated by the fluid in the outlet path;
• a second flow path for providing the pre-heated fluid from the supply path of the heat exchanger to the heating device;
• a first flow modulating device for controlling a flow of fluid along the outlet path;
• and,
• a second flow modulating device for controlling a flow of pre-heated fluid along the supply path;
• wherein the system further comprises a flow control device adapted to control each of the first and second flow modulating devices such that, during use, the fluid flow rates or changes to/in said flow rates in the fluid supply path and outlet path of the heat exchanger correlate substantially in proportion.

A fluid pressure regulating system comprising:

• a fluid pressure modulating device connectable to a fluid supply;
• a first flow modulating device and a second flow modulating device, each having a controllable resistance to fluid flow;
• a first upstream subchamber and a first downstream subchamber having a common first displaceable separator, the displacement of the first displaceable separator determining the relative internal volumes of each of the first subchambers, wherein an upstream side of the first flow modulating device is arranged in pressure communication with the first upstream subchamber and a downstream side of the first flow modulating device is arranged in pressure communication with the first downstream subchamber;
• a second upstream subchamber and a second downstream subchamber having a common second displaceable separator, the displacement of the second displaceable separator determining the relative internal volumes of each of the second subchambers, wherein an upstream side of the second flow modulating device is arranged in pressure communication with the second upstream subchamber and a downstream side of the second flow modulating device is arranged in pressure communication with the second downstream subchamber, the upstream side of the second flow modulating device being arranged for receiving fluid from the fluid pressure modulating device and wherein the first and second separators are coupled mechanically;
• and
• a pressure control system adapted in use to control the fluid pressure modulating device, in accordance with the position of the first and second separators with respect to the subchambers.