Fluid handling – Processes
Patent
1996-06-07
2000-05-09
Lee, Kevin
Fluid handling
Processes
251 3001, 25112904, F16K 31365
Patent
active
060589558
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a differential pressure valve, especially for controlling the liquid flow in a plant for central heating or air-conditioning or a similar plant with a heat carrying, fluid medium, the said differential pressure valve having a membrane controlled by a pressure differential for regulating the flow of the heat carrying medium between an inlet and an outlet, an adjustable closing member between the inlet and the membrane and electrically activated members arranged to be able to close the differential pressure valve by force or by time control independently of the flow in the valve.
BACKGROUND OF THE INVENTION
The plant may for example be a circulation plant where the fluid medium after being heated gives off heat to or after being cooled takes up heat from the surroundings or to/from a secondary fluid medium through at least one heat exchanger or a similar object. Such plants are generally called heating plants or cooling plants (air-conditioning), respectively.
Such a plant is known from U.S. Pat. No. 5,178,324 and is configured in such a manner that it is possible to control the flow in the whole plant, in a single part of the plant or in several sections of a plant being divided into zones.
This plant comprises several heat exchangers, each provided with a valve, the said heat exchangers being arranged to be placed in a number of at least one in each their room in a building where the differential pressure valve is provided in the plant piping.
However, the known plant is encumbered with the drawback that it is controlled solely by the flow in the plant by means of the differential pressure valve. Consequently, the valve cannot operate dynamically and nor can it be adjusted accurately to a predetermined flow in the plant in order to achieve an improved operating economy, if the temperature conditions or the winds inside or outside the building change. Therefore, if such changes occur it will be necessary to intervene to manually bring the closing member into another position.
From U.S. Pat. Nos. 5,213,303, 3,112,094 and 4,180,236 are moreover known differential pressure valves of the type described alone. The known valves are configured to operate statically and therefore they cannot limit the flow to a certain flow in a plant being provided with the valves to ensure a hydraulic balance in the plant. Nor are the valves configured in such a manner that a modification can be carried out while they are mounted. Besides, for reasons of economy it is generally necessary to replace the valves by new valves instead of rebuilding them.
Therefore, it is the object of the present invention to produce a differential pressure valve which can replace the known differential pressure valve as a matter of course, or to indicate such modifications of the known differential pressure valve that these modifications can be mounted on or inserted in the known differential pressure valve without dismounting it to the effect that by means of the modified differential pressure valve the possibility is provided of limiting the flow in the plant automatically to a predetermined, adjustable maximum size in connection with a dynamic reduction of the flow which automatically ensures the hydraulic balance in a versatile plant.
SUMMARY OF THE INVENTION
The object is achieved by a differential pressure valve of the above type which according to the invention is characterized in that the differential pressure valve for preadjustment of the flow has one or more fixed openings, the area of which can be changed linearly by providing the closing member with the electrically activated members.
Due to the dynamic function of the valve the accuracy of the regulation does not depend on fluctuations of the differential pressure and its distribution in the plant. Therefore, the plant can be configured without regard to the concept "valve authority".
A number of advantages are obtained with the differential pressure valve according to the invention:
The possibility is moreover provided of
REFERENCES:
patent: Re32880 (1989-02-01), Lapeyre
patent: 2501583 (1950-03-01), Schafer
patent: 3112094 (1963-11-01), Nees et al.
patent: 4081171 (1978-03-01), Morgan et al.
patent: 4180236 (1979-12-01), Saarem et al.
patent: 4444216 (1984-04-01), Loup
patent: 4477051 (1984-10-01), Ben-Yehuda
patent: 4488702 (1984-12-01), Lapeyre
patent: 5178324 (1993-01-01), Moesby
patent: 5213303 (1993-05-01), Walker
Edwards Steven Kurt
Griswold David Edward
Ibsen Bjarne
Moesby Peter
FlowCon International A/S
Lee Kevin
LandOfFree
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