| 摘要 |
The present invention relates to a modulating fluid control device for a fluid-based heating and cooling system for a measured environment. The control device comprises a body (6), a fluid entry port (8) and a fluid exit port (10) and a valve (12) with actuator (21) located between the ports. In the case of three-way valves a bypass port is also provided thus becoming a mixing or diverting valve. The valve (12) is responsive to input from a sensor and controller to restrict or permit the flow of fluid through the valve (12) dependent upon conditions in the measured environment. The improvement is characterized in that the control device is provided with: (a) a valve controller (20) and means (21) associated therewith to position the valve (12) and thereby regulate the flow of fluid through that valve (12), and (b) flow detection means (22) associated with the valve (12) to measure the flow of fluid at a location in the system and provide to the valve controller (20) a feedback signal representative of that flow rate. The sensor and controller is adapted to provide a signal to the valve controller (20) and the valve controller (20) is arranged to control the valve (12), and so control the flow of fluid in the system responsive to signals received from the sensor and controller. The flow detection means (22) and the valve controller (20) are arranged to maintain a required rate of flow of fluid through the system as measured by the flow detection means (22), which promotes desired environmental conditions in the measured space.
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