GB2264349A

GB2264349A - Valve for air conditioning systems

Info

Publication number: GB2264349A
Application number: GB9303697A
Authority: GB
Inventors: Malcolm Cyril Munro; Colin Lindsay Box
Original assignee: AIR GRILLES Pty Ltd
Current assignee: AIR GRILLES Pty Ltd
Priority date: 1992-02-24
Filing date: 1993-02-24
Publication date: 1993-08-25
Anticipated expiration: 2013-02-24
Also published as: HK171295A; GB9303697D0; GB2264349B

Abstract

A valve for use in an air-conditioning system has two pivotally mounted valve members (15, 16), pivotable about an axis or axes (17A) transverse to the duct (10) from which each valve member (15, 16) extends in a downstream direction. Actuating means (25) such as a mechanically driven pivotal linkage system displaces the valve members (15, 16) towards or away from one another to move between open and closed positions of the valve. The valve members may form an aerofoil shape when the valve is fully open. The valve may be mounted in a duct which is in turn mounted in a larger duct (fig 4) in order to reduce noise. <IMAGE>

Description

VALVE FOR AIR CONDITIONING SYSTEMS The present invention relates to a variable volume valve for use in a gas flow system such as an airconditioning system, which typically will comprise a number of separate ducts and outlets and valves are provided at suitable locations to close or partially close a duct to restrict air flow according to the demands of the system.

One known form of variable volume valve is known as a butterfly valve and comprises a simple circular plate mounted on a pivotal shaft extending in the plane of the plate and adapted to be driven so as to vary the valve's position relative to the circular duct in which it is mounted. Another known system utilises two apertured plates which are slidable or otherwise displaceable relative to one another to vary the degree of overlap of the apertures thereby varying the cross-sectional area of the duct and in this way the air flow is controlled.

Particularly for air-conditioning systems it is desirable to manufacture economically a variable volume valve which can readily be adjusted for example by an automatic control system and, particularly in the fully opened position, will generate the minimum amount of noise and produce a very low pressure drop. The present invention is concerned with new and useful alternatives to previous proposals and it is believed that in at least preferred embodiments will provide a structure which is inexpensive to manufacture, durable and reliable and most importantly will generate little noise when in use.

According to the present invention, there is provided a variable volume device for a valve for use in a duct of an air-conditioning system or the like and comprising first and second valve members, each valve member being pivotal around an axis which in use is arranged to extend across a duct, each valve member extending from its pivot axis in a downstream direction along the duct to a free end portion, and actuating means provided for displacing the respective valve members towards or away from one another so as to move between open and relatively closed positions of the valve.

Preferably, the valve members are hingeably interconnected through a common hinge which extends generally centrally across the valve duct so that the pivot axis of the valve members coincide. Alternative embodiments are possible including the valve members having separate hinge connections to a connecting element.

In a preferred embodiment, the actuating means operates symmetrically to displace the valve members by substantially the same amount in opposite directions whereby a symmetrical valve structure is provided.

However, the invention also extends to embodiments which are not of such a form and it is also possible for the valve members to be separately actuated and to move by different amounts.

The invention extends to a valve comprising the device described above mounted in the valve duct.

Preferably, the duct is of rectangular cross-sectional shape, each valve member having lateral edges which in use are disposed adjacent opposite side walls of the valve duct and the free end portion of each valve member extends transversely across the duct and in the fully closed position of the valve lies adjacent to or in abutment with a wall of the duct disposed at right angles to the opposite side walls.

In general terms, at least a preferred embodiment is one in which the valve members cooperate in a clam-like form with the actuating means located inside the clam shape.

Preferably, each valve member is of curved form for example generally airfoil in shape or, for maximum economics of manufacture, may comprise a series of flat panel portions which are integrally formed and connected by bends at spaced points.

Any suitable form of actuating means can be adopted, but a preferred and advantageous mechanism is one comprising a shaft arranged to extend laterally across the valve duct and between the valve members, a rocker arm being fixed to the shaft and rotatable therewith and pivotal links are linked to respective ends of the rocker arm and to respective portions of the valve members whereby rotation of the rocker arm in a first direction moves the valve members towards each other and contrary rotation moves the valve members away from one another and to the closed position of the valve.

Advantageously the valve duct is mounted in a main duct of greater transverse dimension and extending in the downstream direction whereby noise generation is substantially avoided. For example, with a valve duct having a traverse dimension of the order of 200mm, the main duct has a traverse dimension of about 300mm. In other words a space of about 5Omm has been found advantageous between the periphery of the valve duct and the interior of the main duct.

The invention extends to an air-conditioning system including a multiplicity of ducts including strategically placed variable volume valves each adapted to be driven by an electrically or pneumatically powered actuator, and the system having a control device for sensing air flow requirements and providing appropriate actuation signals to control the system.

For illustrative purposes only an embodiment of the invention will now be described with reference to the accompanying drawings, of which: Figure 1 is a schematic cross-sectional side elevation through an embodiment of variable volume valve in a closed position; Figure 2 is a cross-sectional view corresponding to figure 1, but showing the valve in an open position and omitting the actuating linkage for the purpose of clarity; Figure 3 is a plan view of the valve of figure 1 and 2 and omitting for clarity valve blades and linkages; and Figure 4 is a view on a reduced scale in section and schematically illustrating the valve mounted in a main duct.

As will be best seen from figure 1, the valve comprises a rectangular duct 10 having side walls 11, a top wall 12 and a bottom wall 13, and mounting a pair of valve blades namely upper blade 15 and lower blade 16, which are pivotally interconnected at an upstream interengagement position on a hinge pin 17A. Each valve blade is generally arcuate, but pressed from a flat panel with bends 17, 18 and 19 and terminating in a lip 20 at its free end. Each valve blade has a centrally located lug 22 which is connected pivotally through a linkage 23, and which in turn is pivotally attached to a respective end of a rocker arm 24 fixed to a main mounting rod 25.

As shown in figure 3, the mounting rod 25 extends right through the duct and is pivotally mounted on nylon bushes 27. The rod is adapted to be rotated by an electric or pneumatic actuator controlled in a conventional manner and responsive to conventional devices such as switches or thermostats.

It will be seen that rotation of the rocker arm in a clockwise direction when viewed as in figures 1 and 2 causes the valve blades to move to be adjacent to one another and the profile is such that a close approximation to an airfoil shape is achieved, whereby a low pressure drop across the device is provided with only a low degree of noise generation.

In a typical embodiment, the valve duct has a rectangular shape with a height of 200mm across the duct and as shown in figure 3 this is mounted in a larger dimensioned discharge duct 28, which preferably includes about 25mm of acoustic insulation 29 in the wall. A spacing of about 50mm from the edge of the valve duct to the discharge duct has been found to be most beneficial in avoiding generation of noise.

Claims

1. A variable volume device for a valve for use in a duct of an air-conditioning system or the like and comprising first and second valve members, each valve member being pivotal around an axis which in use is arranged to extend across a duct, each valve member extending from its pivot axis in a downstream direction along the duct to a free end portion, and actuating means provided for displacing the respective valve members towards or away from one another so as to move between open and relatively closed positions of the valve.

2. A device as claimed in claim 1 and wherein the valve members are hingeably interconnected about a common hinge having a common hinge axis which extends generally centrally across the valve duct when in use so that the pivot axis of the valve members coincide.

3. A device as claimed in claim 1 or claim 2 and wherein the valve members are mounted to be displaced by the actuating means to a substantially equal and opposite extent and the valve members define a substantially symmetrical structure viewed at right angles to the pivot axis of each of the valve members.

4. A device as claimed in any one of the preceding claims and wherein the actuating means comprises a rotatable shaft extending across the valve duct and adapted to be rotated when in use, the shaft carrying a rocker arm which pivotally connects to respective pivotal links which are pivotally connected to the respective valve members.

5. A device as claimed in any one of the preceding claims and wherein each valve member comprises a sheet bent to form a profile of generally convex form whereby an approximation of an air foil shape is provided.

6. A device as claimed in claim 5, and wherein an end portion of each valve member has a substantially flat surface adapted to come into abutment with or lie adjacent a corresponding flat wall of the duct when the valve is in the fully closed position.

7. A device as claimed in any one of the preceding claims and wherein the first and second valve members are constructed to be of clam-like form.

8. A device as claimed in any one of the preceding claims and wherein the first and second valve members are shaped and configured to cooperate in use with a duct of rectangular cross-section.

9. A device as claimed in any one of the preceding claims and wherein the actuating means comprises a shaft arranged to extend laterally across the valve duct and between the valve members, a rocker arm being fixed to the shaft and rotatable therewith and pivotal links are linked to respective ends of the rocker arm and to respective portions of the valve members whereby rotation of the rocker arm in a first direction moves the valve members towards each other and contrary rotation moves the valve members away from one another and to the closed position of the valve.

10. A variable volume valve comprising a device as defined in any one of the preceding claims when mounted in a valve duct.

11. A variable volume valve as claimed in claim 10 and wherein the valve duct is mounted in a main duct of greater transverse dimension and extending in the downstream direction whereby noise generation is substantially avoided.

12. A variable volume valve as claimed in claim 11 and wherein the main duct has a transverse dimension approximately 50% greater than the transverse dimension of the valve duct.

13. A variable volume valve for an air conditioning system and substantially as herein described with reference to the accompanying drawings.

14. An air conditioning system having a multiplicity of the ducts, at least some of which incorporate a variable volume valve as claimed in any one of the claims 10 to 13, each of the variable volume valves being adapted to be driven by a powered actuator in response to a control device for the system, the control device operating to sense air flow requirements and provide appropriate actuation signals.