GB2213563A

GB2213563A - Valve with secondary seat adjacent removable outlet member

Info

Publication number: GB2213563A
Application number: GB8828733A
Authority: GB
Inventors: Peter Cox; David Grayson
Original assignee: WEBBER ELECTRO COMPONENTS LIMI
Current assignee: WEBBER ELECTRO COMPONENTS LIMI
Priority date: 1987-12-08
Filing date: 1988-12-08
Publication date: 1989-08-16
Anticipated expiration: 2008-12-08
Also published as: GB8828733D0; GB2213563B; GB8728618D0

Abstract

A solenoid valve comprises a removable tubular outlet member 3 against which a diaphragm 5 seals and a concentric circumferential wall 20 slightly below the level of the outlet end face, against which the diaphragm can seal on removal of the tubular outlet member for cleaning pulses. In an alternative embodiment the diaphragm can seal on removal of the outlet member, against the end face 24 of chamber 6. <IMAGE>

Description

Self-sealing Valve This invention relates to valves and has particular, but not exclusive, reference to diaphragm valves intended for use in connection with vending equipment.

In many vending machines, there is a hot water tank which stores hot water for use in the manufacture of a beverage. The hot water is dispensed into a tank under the control of electronic circuitry, which circuitry in part controls a solenoid valve to dispense a measured quantity of water.

In many areas, the equipment is required to use hard water and the valves tend to become clogged with scale. It is necessary therefore occasionally to dismantle the valves to clean them and to remove the scale. The valves often include a flow restrictor which is sensitive to scale formation.

Heretofore, it has been necessary to drain down the hot water system, dismantle the valve, clean the valve, reassemble the valve and refill the system before it can be tested. In many cases, it can take as long as one hour to drain the system and another hour to refill it. It is necessary therefore for the engineer to spend an excessive and unnecessary amount of time waiting while the system drains and refills.

The present invention is particularly concerned with a valve suitable for use in the hot water system of a vending machine, although it is possible that it may have other applications.

By the present invention there is provided valve means including a valve body having a central chamber with an inlet and an oulet, the outlet being through a removable tubular member, valve sealing means engageable with a peripheral end wall of the tubular member to form a seal, the valve sealing means being movable away from the periphery to open the valve and movable into contact with the periphery to seal the valve, characterised in that surrounding the peripheral wall of the tubular member is a secondary sealing surface such that on axial removal of the tubular member, the valve sealing means moves to engage the secondary sealing surface to seal the valve when the valve is in the closed condition.

The secondary sealing surface may be provided on an upstanding peripheral wall surrounding the tubular member and extending into the chamber.

Alternatively, the secondary sealing surface may comprise the end face of the chamber.

The peripheral wall may extend from i mm to 2 mm in an axial direction beyond the peripheral end of the tubular member.

The sealing means may comprise a diaphragm forming one portion of the wall of the central chamber and having a surface adapted to engage the peripheral end of the tubular member. The tubular member may be circular in cross-section and the upstanding peripheral wall may be concentric with the tubular member.

There may be provided an electromagnet to move the sealing member. The tubular member may be provided with '0' ring seals to seal the tubular member into the body of the valve.

There may be provided a flow control in the form of a transverse variable effect obturator which locks the tubular member into the body of the valve and which can control the rate of flow of liquid through the valve.

The body of the valve may be formed of a suitable plastics material such as polysulphone. The diaphragm may be made of a food grade nitrile rubber material The sealing means may be maintained in contact with the peripheral wall of the tubular member by a spring.

By way of example, embodiments of the present invention will now be described with reference to the accompanying drawings of which FIGURE 1 is a partial cross-section through a solenoid valve in accordance with the prior art, and FIGURE 2 is a similar partial cross-section of a solenoid valve in accordance with the present invention Referring to Figure 1, this shows a valve body 1 having an inlet 2 and an outlet via a tubular member 3. The peripheral end wall 4 of the tubular member is sealed by means of a rubber diaphragm sealing member 5. As shown in Figure 1, the valve body defines a central chamber 6 with the valve member 5 controlling flow of liquid through the chamber. The valve member 5 is shown in the closed condition and the valve is opened by means of solenoid 7 which, when activated lifts armature 8 in the conventional manner.A suitable spring 9 maintains the valve in the closed condition when the solenoid 7 is not energised.

The valve shown in Figure 1 is intended for use in the control of hot water in a vending machine for beverages. When used in hard water conditions, there is a danger of the build up of limescale on the peripheral end wall 4 or on the flow restrictor 10 which is mounted transverse to the bore 11 of tubular member 3. The tubular member can be withdrawn from the body by removal of the locating tag 12, withdrawing to the left flow restrictor 10 and then withdrawing the tubular member 3 downwardly. An 'o' ring 13 seals the tubular member 3 in the valve body 1 and further '0' rings 14, 15 seal the flow restrictor within the tubular member 3.

With the prior art valve shown in Figure 1, it is necessary to drain down the hot water system before removal of the tubular member 3 for cleaning purposes because the water will simply flow through inlet 2 and out through the space previously occupied by tubular member 3.

Referring now to Figure 2, this shows a solenoid valve very similar to that illustrated in Figure 1 except that it is modified in accordance with the present invention. Like parts of the valve shown in Figure 2 are given like reference numbers to those shown in Figure 1.

However, in the embodiments illustrated in Figure 2 a peripheral wall 20 is provided around that portion of the tubular member 3 which extends into the chamber 6. A further '0' ring 21 is also provided on the tubular member 3. As can be seen in Figure 2, the periphery of the end wall 20 is slightly below that of the peripheral end wall 4 of the tubular member 3.

The gap 22 is so chosen that when the tubular member 3 is withdrawn, the spring 9 can force the sealing member 5 into contact with the peripheral end wall 23 of the end wall 20. Thus, removal of the tubular member 3 simply results in sealing of the valve between the seal 5 and the end wall 23. The tubular member and flow restrictor 10 can then be cleaned and the valve reassembled without any loss of hot liquid.

It will be seen that withdrawal downwardly of the tubular member 3 will not result in any leakage of hot water of any significant amount in that the seal between sealing member 5 and end wall 4 will remain in existence until sealing member 5 contacts end wall 23.

Similarly, on reassembly, the seal between the sealing member 5 and end wall 23 will not be broken until end wall 4 of tubular member 3 makes contact with and seals up against sealing member 5.

It will be appreciated that both the tubular member and the end wall 20 could be shortened so that they did in fact coincide with the end face 24 of chamber 6.

The material of which the valve body is made is any suitable food grade plastics material such as a polysulphone. The diaphragm can be made of any suitable material such as a nitrile rubber. It will also be appreciated that rather than using a diaphragm, a piston and sealing arrangement could be provided.

Claims

CLAIMS:

1. Valve means including a valve body having a central chamber with an inlet and an outlet, the outlet being through a removable tubular member, valve sealing means engagable with a peripheral end wall of the tubular member to form a seal, the valve sealing means being movable away from the periphery to open the valve and movable into contact with the periphery to seal the valve, characterised in that surrounding the peripheral wall of the tubular member is a secondary sealing surface such that on axial removal of the tubular member the valve sealing means moves to engage the secondary sealing surface to seal the valve when the valve is in the closed condition.

2. A valve as claimed in Claim 1 in which the secondary sealing surface is provided on an upstanding peripheral wall surrounding the tubular member and extending into the chamber

3. A valve as claimed in Claim 1 in which the secondary sealing surface comprises the end face of the chamber.

4. A valve as claimed in Claim 2 in which the peripheral wall extends from j mm to 2 mm in an axial direction beyond the peripheral end of the tubular member.

5. A valve as claimed in any one of Claims 1 to 4 in which the sealing means comprises a diaphragm forming one portion of the wall of the central chamber and having a surface adapted to engage the peripheral end of the tubular member.

6. A valve as claimed in any one of Claims 1 to 5 in which the tubular member is circular in cross section.

7. A valve as claimed in Claim 2 in which the upstanding peripheral wall is concentric with the tubular member.

8. A valve as claimed in any one of Claims 1 to 7 in which there is provided an electromagnet to move the sealing member.

9. A valve as claimed in any one of Claims 1 to 8 in which the tubular member is provided with '0' ring seals to seal the tubular member into the body of the valve.

10. A valve as claimed in any one of Claims 1 to 9 in which there is provided a flow control in the form of a transverse variable effect obturator which locks the tubular member into the body of the valve and which can control the rate of flow of liquid through the valve.

11. A valve as claimed in any one of Claims 1 to 10 in which the body of the valve is formed of a plastics material, preferably polysulphone.

12. A valve as claimed in any one of Claims 1 to 11 in which the diaphragm is made of food grade nitrile rubber.

13. A valve as claimed in any one of Claims 1 to 12 in which the sealing means is maintained in contact with the peripheral wall of the tubular member by a spring.

14. A valve substantially as herein described with reference to and as illustrated by Figure 2 of the accompanying drawings.