GB2276222A

GB2276222A - Fluid control valve

Info

Publication number: GB2276222A
Application number: GB9305776A
Authority: GB
Inventors: Geoffrey Shepherd
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-03-19
Filing date: 1993-03-19
Publication date: 1994-09-21
Anticipated expiration: 2013-03-19
Also published as: GB9305776D0; GB2276222B

Abstract

A fluid control valve for central heating systems includes a valve body (10) having a fluid inlet (11) and a fluid outlet (12) communicating with an internal chamber (13). A primary valve member (15) is movable between a first position in which a primary valve aperture (14) is closed to the passage of fluid from the inlet (11) to the outlet (12) and a second position in which fluid may flow from the inlet (11) to the outlet (12). A flexible diaphragm (16) supports the valve member (15) and divides the chamber (13) into two separate volumes. Flow through lateral ports in the valve member (15), which connect the two separate volumes, is controlled by a disc 50 on a secondary valve member (17) positioned within the valve member (15). The primary valve member (15) has a drain aperture (33) which is opened when the secondary valve member (17) closes the lateral ports, so as to allow fluid in that volume of the chamber (13) remote from the primary valve aperture (14) to drain out and the primary valve member (15) to open. Electromagnetic means (18, 19) actuates the secondary valve member (17). <IMAGE>

Description

FLUID CONTROL VALVE This invention relates to fluid control valves primarily, though not exclusively, intended for use with hot water central heating radiators.

Many central heating systems use manual control valves to control the temperature of radiators. Generally, since in fact the valve controls the rate of flow of hot water through the radiator, such control is not very effective. The actual temperature of the radiator depends upon a number of factors, including the water temperature and the rate of heat loss from other radiators which are in the heating circuit.

To some extent this problem may be overcome by the use of thermostatic radiator valves. Usually these use a capsule of liquid or wax which expands as its temperature increases, and this expansion may be used to control the flow of hot water. Such valves are usually adjustable so that the temperature of operation may be varied at will.

However, since the valves are usually mounted the pipe carrying hot water and often close to the radiator, they are to some extent affected by the temperature of the radiator or water pipe as much as by the ambient temperature of the room in which the radiator is located.

A more satisfactory result would be achieved if the valve could be made to respond to the electrical output from a room thermostat mounted in a more suitable position. This is possible but requires an electrically-operated valve which may be opened or closed by the thermostat output. An electrically-operated valve would have other uses as well. For example, such a valve could be used in buildings with many rooms, such as hotels or office blocks, so that the radiators in unused rooms could be shut off or turned down by remote control to save energy.

Valves of this type are known but generally use too much electric power or are too costly to be acceptable for use in large numbers. A valve with a very low force actuator will consume less electric power than known types of valve.

It is known to provide remotely-controlled valves for use with central heating systems in which the valve is actuated by a electrical heating element place around or in close proximity to the capsule of a standard type of thermostatic valve. Apart from the amount of energy required to operate such a heater and the inevitable heat losses associated with its use, the response time of such an actuating mechanism is slow and not always adequate.

It is an object of the invention to provide a fluid control valve with a very low force actuator which may therefore be operated electrically whilst using less electric power than known types of valve.

Such a valve may be operated by other types of actuator.

According to the present invention there is provided a fluid control valve which valve includes a valve body having a fluid entry passage and a fluid exit passage communicating with an internal chamber having a primary valve aperture located between the two said passages, a primary valve member fitting into said primary valve aperture and movable between a first position in which the said primary valve aperture is closed to the passage of fluid from the entry passage to the exit passage and a second position in which fluid may flow from the entry passage to the exit passage, a flexible diaphragm supporting the primary valve member for said movement between its first and second positions and dividing the said chamber into two separate volumes communication between which is provided by a secondary valve aperture in said primary valve member, a secondary valve member carried by the primary valve member and operable to move between a first position in which the two volumes of the chamber are in communication with one another and a second position in which the two volumes of the chamber are isolated from one another, the primary valve member having a drain aperture which is opened when the secondary valve member is in its second position to allow fluid in that volume of the chamber remote from the primary valve aperture to drain out of that volume as the primary valve member moves from its first position to its second position, and actuating means arranged to move the secondary valve member between its two positions.

The invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a sectional elevation view of the assembled valve in the closed position, according to an embodiment of the invention; Figure 2 shows a sectional plan view of the body of the valve of Figure 1 along the line A-A; Figure 3 shows enlarged sectional plan and elevation views of the primary valve member of Figure 1; Figure 4 shows enlarged sectional plan and elevation views of the body of the secondary valve member; Figure 5 shows enlarged sectional plan and elevation views of a further part of the secondary valve member; and Figure 6 is a view of the complete valve in the open position, to the same scale as Figure 1.

Referring now to Figures 1 and 2, the complete valve consists of a number of component parts the form and function of which will be described in greater detail later. A valve body 10 has a fluid entry passage 11 and a fluid exit passage 12 and, connecting these two passages, a chamber 13 and a primary valve aperture 14. Positioned in the chamber so as to move into and out of the primary valve aperture 14 is a primary valve member 15, which is held in position by a flexible diaphragm 16. Inside the primary valve member is a secondary valve member 17, movement of which is controlled by an actuator, shown here as comprising an electromagnet coil 18 acting upon an armature 19 attached to the secondary valve member 17.

Referring to Figures 1 and 2, the valve body 10 comprises a generally cylindrical body having the fluid entry passage 11 in the centre of its bottom surface. This communicates with the internal chamber 13 from which the primary valve aperture 14 communicates with the fluid exit passage 12. The primary valve aperture 14 may have a tapered seat as shown in Figure 1. Communication between the fluid entry passage 11 and the chamber 13 may be by means of a number of passages 20 formed through the body 10. Part of the body 10 is formed by a removable cover 21, the purpose of which will be described later. A number of holes 22 are provided to accommodate bolts or screws which secure the cover 21 to the remainder of the body.

Figure 3 shows the primary valve member 15 which is arranged to control the opening of the primary valve aperture 14. The member 15 comprises an upper part 30 of hollow cylindrical form, tapering to a lower part 31 in the form of a cylinder of smaller diameter. This lower part 31 is of such dimensions that it may pass through the primary valve aperture 14 in the body 10. The primary valve member 30 carries a seal, such as an O-ring seal as shown at 32, at the end of the lower part 31 adjacent to the taper. The O-ring may be located in a groove as shown and forms a seal in the primary valve aperture when the valve is closed, as will be described later. The lower part of the primary valve member 15 has a bore 33 formed through it to communicate with the hollow upper part of the member. This upper part has a number of apertures 34 formed through it, four being shown in Figure 3.

The primary valve member 15 is held in position by a thin flexible diaphragm 16. This is clamped at its outer edge between the body 10 and the removable cover 21 and has a central aperture into which the primary valve member 15 is secured by a collar 35. The diaphragm is impervious to the fluid which the valve is used to control.

Positioned inside the primary valve member 15 is the secondary valve member 17. As shown in greater detail in Figure 4, this comprises a cylindrical head 40, tapering to a point 41, attached to a spindle 42 having an enlarged end 44. A groove 43 is formed around the head 40. Carried in the groove 43 is a disc-shaped valve member 50, shown in Figure 5. This has a thickness greater than the height of the apertures 34 in the upper part of the primary valve member 15 and has a number of apertures 51 formed through it around the central aperture 52 which fits in the groove 43 in the secondary valve member 17.

Figure 1 shows the assembled valve in the closed position, with the lower part 31 of the primary valve member 15 positioned in the primary valve aperture so that the aperture is sealed by the O-ring 32.

It will be seen that the spindle 42 of the secondary valve member 17 extends through the cover 21 into a housing 23 of non-magnetic material which accommodates the enlarged end 44 of the spindle and a light coil spring 24 which acts to raise the secondary valve member. The end 44 of the spindle carries the armature 19 of an electromagnet, whilst outside the housing 23 is located the coil 18 of the electromagnet. The electromagnet has an iron circuit 25 in which is a gap 26 located adjacent to the armature 19 when the valve is in the closed position shown in Figure 1.

With the valve components in the position shown in Figure 1 the valve is closed as stated above and is held in this position by the magnetic field of the energised electromagnet coil 18 acting on the armature 19. This causes the armature 19 to exert a force greater than that of the light spring 24. It will be seen that the apertures 34 in the upper part of the primary valve member are open as the secondary valve member 17 is in its lowest position with the valve disc 50 clear of these apertures. As a result, the fluid in the fluid entry port 11 and in the chamber 13 is also able to occupy the space above the diaphragm 16, thus equalising the fluid pressure on the two sides of the diaphragm. This means that only a very small force is required to keep the valve in the closed position, sufficient force to overcome that exerted by the spring 24.

To open the valve, the electromagnet coil 18 is deenergised. This allows the spring 24 to raise the secondary valve member 17 so that the disc 50 closes the apertures 34 in the upper part of the primary valve member 15. The spring 24 raises the secondary valve member 17 and , as it does so, the fluid on the upper side of the diaphragm 16 is able to drain away through the bore 33 in the lower part of the secondary valve member. The fluid in the chamber 13 exerts an upward pressure on the diaphragm 16 and hence assists in the lifting of the primary valve member, thus opening the valve. When the valve is in the open position its component parts occupy the relative positions shown in Figure 6.

To close the valve from the open position the electromagnet coil 18 is energised, pulling the armature down and moving the secondary valve member to a position where the bore 33 is closed and the disc 50 opens the apertures 34 in the primary valve member 15. As the secondary valve member continues to move down it moves the primary valve member with it. At the same time the fluid in the valve chamber 13 is able to flow through the apertures 34 into the space above the diaphragm so as to equalise the pressure on both sides of the diaphragm. When the movement of the primary valve member is such that the O-ring 32 closes the primary valve aperture then the valve is fully closed.

As already stated, the electromagnet only has to exert sufficient force on the valve mechanism to overcome the spring force of spring 24, since the fluid in the valve chamber assists in both the opening and closing of the valve. This not only reduces the power consumed by the electromagnet to a very low level, perhaps only 3-5 watts, but also reduces the operating time of the valve. It is the power consumption which is important, particularly if the valve is to be used in a situation where there may be a large number of valves to be operated at any one time, since power is consumed by the electromagnet coil 18 for as long as the valve is kept in the closed position.

It will be appreciated that the drawings show only one embodiment of the invention and that many of the dimensions and forms of the component parts any be changed without departing from the essential features of the invention. Certain parts of the valve must be of non-magnetic materials, particularly the cover 21 which is positioned between the electromagnet coil 18 and the armature 19. Other parts may be made of plastics materials, particularly the valve body 10, cover 21 and the diaphragm 16, though these may equally be made from other materials including suitable metals. The location and arrangement of the fluid inlet and exit ports may be changed. It will be appreciated that directional terms such as "upper" and "lower" or "upwards" and "downwards" are purely relative terms and do not imply any physical restrictions on the construction of the valve.

It will be appreciated that, although the particular value of the invention is in its application to an electrically-operated valve, other forms of actuating mechanism may be used. However, in many instances there will be simpler alternatives to the form of valve described. It would be possible, for example, to extend the spindle 42 through the top of the housing 23 and use some form of mechanical actuator operating on the end of the spindle. However, this would require the provision of a seal between the spindle and the housing to prevent the escape of fluid from the valve body. This seal would present considerable resistance to the movement of the spindle and thus negate the low-operating force feature of the valve described. An alternative would be to use an hydraulic mechanism, which could be done without the need to provide a seal acting against the spindle Such alternative mechanical or hydraulic actuating means may not require the presence of the light spring 24 as the actuating means may be arranged to provide the necessary movement of the valve mechanism in both directions.

As already stated, the valve described has particular application to central heating systems, particularly in large building where remote control is beneficial. It will be appreciated, however, that the valve may be used for the control of any fluid in any situation.

Claims

1. A fluid control valve which valve includes a valve body having a fluid entry passage and a fluid exit passage communicating with an internal chamber having a primary valve aperture located between the two said passages, a primary valve member fitting into said primary valve aperture and movable between a first position in which the said primary valve aperture is closed to the passage of fluid from the entry passage to the exit passage and a second position in which fluid may flow from the entry passage to the exit passage, a flexible diaphragm supporting the primary valve member for said movement between its first and second positions and dividing the said chamber into two separate volumes communication between which is provided by a secondary valve aperture in said primary valve member, a secondary valve member carried by the primary valve member and operable to move between a first position in which the two volumes of the chamber are in communication with one another and a second position in which the two volumes of the chamber are isolated from one another, the primary valve member having a drain aperture which is opened when the secondary valve member is in its second position to allow fluid in that volume of the chamber remote from the primary valve aperture to drain out of that volume as the primary valve member moves from its first position to its second position, and actuating means arranged to move the secondary valve member between its two positions.

2. A valve as claimed in Claim 1 in which the primary valve member contains apertures permitting communication between the two volumes of the chamber, these apertures being closed by the secondary valve member when the valve is in the open position.

3. A valve as claimed in Claim 2 in which the secondary valve member carries a disc member operable to close the said apertures, the disc member having apertures formed therein to permit the flow of fluid from the volume of the chamber above the diaphragm through the drain aperture in the primary valve member.

4. A valve as claimed in any one of Claims 1 to 3 in which the diaphragm is secured at its outer edge to the body of the valve and at its centre to the primary valve member.

5. A valve as claimed in any one of the preceding claims in which the actuating means comprise electromagnetic means.

6. A valve as claimed in Claim 5 in which the electromagnetic means include an armature attached to the secondary valve member and an electromagnet coil located outside the body adjacent to the armature and a light spring arranged to urge the secondary valve member towards its open position.

7. A fluid control valve substantially as herein described with reference to the accompanying drawings.