GB2267951A

GB2267951A - Fluid flow control valves

Info

Publication number: GB2267951A
Application number: GB9310964A
Authority: GB
Inventors: Royston Leonard Edwards
Original assignee: IMI Santon Ltd
Current assignee: IMI Santon Ltd
Priority date: 1992-06-17
Filing date: 1993-05-27
Publication date: 1993-12-22
Anticipated expiration: 2013-05-27
Also published as: GB2267951B; GB9310964D0

Abstract

A push-operated tap for securing in a wall 2 of a waterheater containing near-boiling water 14, comprises a hollow body 1 having an inlet 14 and an outlet spout 6 in communication with a bore 3 of circular cross-section formed in the body. The bore 3 has co-axially located in it a moulded, resilient, cup-shaped sleeve 7 the open end S of which is secured to the body 1. In the tap-closed position, the sleeve 7 is substantially in its relaxed, as moulded condition and has a bulged annular wall portion 13 whose external surface sealingly engages with the wall of the bore 3 thus blocking the flow of water 14 from the in lot 4 to the outlet spout 6/A manually depressible piston 12 is located within the sleeve 7 and, when depressed, stretches the sleeve 7 longitudinally and causes the bulged portion 13 to contract radially out of sealing engagement with the bore wall whereupon water 14 will flow along the annular passageway 11 and issue from the spout 6. When the depressive force is removed, the sleeve 7 resiles back, together with the piston 12, to its original tap-closed position. <IMAGE>

Description

Fluid Flow Control Valves This invention relates to fluid flow control valves, especially, but not exclusively, to push-operated taps for dispensing, for example, beverages or the hot or.cold water constituent of a beverage.

According to the present invention there is provided a fluid flow control valve comprising a body having a bore therein and a fluid inlet and a fluid outlet in communication with the bore, and a flexible sleeve located longitudinally, preferably coaxially, in the bore, the sleeve being deformable by actuating means between a valve-open position in which there is defined between the bore wall(s) and the external surface(s) of the sleeve a fluid flow passageway interconnecting the inlet and outlet and a valve-closed position in which at least a portion of the sleeve externally is in circumferential sealing engagement with the bore wall(s) at a position intermediate the inlet and outlet thereby blocking the passageway.

A valve, in the form of a push-operated tap, constructed in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings in which: FIGURE 1 is sectional side elevation of the tap, mounted in a water-boiler, in its closed position; and FIGURE 2 is a similar view to that of Figure 1 but showing the tap in its fully open position.

Referring to the drawings, the tap comprises a body 1 which is sealingly secured into an aperture in a wall 2 of a water-boiler which may, for example, be as described in our earlier UK patent application No 2 262 594. The body 1 defines a bore 3 of circular cross-section, an inlet 4 and an outlet 5 which is connected to a spout 6 for delivering boiling water into a cup or other receptacle. Coaxially mounted in the bore 3 is a generally circular cylindrical sleeve 7, moulded in elastic material, that is open at its outer end 8 and closed at inner end 9. The sleeve 7 is sealingly secured, at its open end 8, into the body 1 by a circular cylindrical bush 10 and defines, together with the wall of the bore 3, an annular passageway 11. The bush 10 also acts as a bearing for an axially movable piston 12 whose inner end abuts the end 9 of the sleeve 7.As can be seen, the piston 12 is retained in place by means of a releasable snap fit engagement with the sleeve 7.

Referring in particular to Figure 1, this shows the tap in its normal, closed position and in this position the sleeve 7 is more or less in its relaxed, as-moulded condition. More particularly it will be seen that the sleeve wall, which is substantially of constant thickness, has a bulged (or "bellowed") portion 13 which circumferentially sealingly engages with the wall of the bore 3, the sealing engagement being enhanced by the head of water in the boiler acting on the closed end 9 of the sleeve 7. The passageway 11 is thus blocked and flow of liquid from the inlet 4 to the outlet 5/spout 6 is prevented. In the valve-closed position it will also be seen that the piston 12 is in a retracted position.

However, and with reference to Figure 2, upon manual depression of the piston 12, the sleeve 7 becomes axially extended and, therefore, the bulged portion 13 contracts radially out of sealing engagement with the wall of the bore 3. The passageway 11 thereby interconnects the inlet 4 and the outlet 5 and hot water 14 issues from the spout 6. The rate of dispensation may be varied by varying the extent of depression of the piston 12, for example from a trickle to full flow (the position shown in Figure 2).

When the piston 12 is depressed, a tensile strain, or increased tensile strain, is imparted to the sleeve 7 which, upon removal of the manual (eg finger) depressive force from the piston 12, automatically returns the sleeve 7 and the the piston 12 to the position shown in Figure 1, and the tap thus re-assumes its closed position.

As will be appreciated, the various components of the tap specifically described above may be fabricated from any suitable materials. By way of example, we prefer to make the body 1 of brass, the piston 12 of a relatively rigid plastics material and the sleeve 7 of a silicone rubber.

As will be further appreciated, the tap specifically described above is merely one example of a valve constructed in accordance with the invention.

Various alternative constructions are, as will be readily apparent, possible within the scope of the invention as defined above. For example, the bore could be of any cross-section consistent with a reliable fluid-tight seal being attainable between the sleeve and the bore wall(s) in the valve-closed position, although clearly a circular cylindrical bore/sleeve is preferred for ease of manufacture.

Further, whereas in the embodiment described above the tap automatically returns to its closed position by virtue of the tensile strain imparted to the sleeve, the sleeve could be such that it returns to its closed position only in response to movement of the piston or other actuating means. For example, where the bore is of circular cross-section, the sleeve could simply comprise a truly cylindrical sleeve, preferably of an elastomeric material, that is bulged by axially compressing it, by means of a piston or other actuating means secured to the sleeve, into sealing engagement with the bore wall(s) so as to close the valve and that reverts to its original cylindrical form upon movement of the piston or other means in an opposite sense so as to open the valve.

In such a case, the piston/sleeve combination would preferably be urged into the valve-closed position by a compression spring.

Yet further, deformation of the sleeve may occur essentially only in a radial or only in an axial direction (as distinct from in an axial and radial direction as occurs in the tap described with reference to the drawings). Thus, the sleeve may be forced radially outwards, so closing the valve, by a camming or wedge-type co-operation with a piston or other actuating means located within the sleeve, the sleeve resiling radially into the valve-open position upon retraction of the piston or other actuating means; or a peripheral sealing flange formed on the external surface of the sleeve could be brought into and out of engagement with a seat defined by a shoulder formed in the bore, simply by causing deformation, ie stretching, of the sleeve substantially only in an axial direction.

As will also be appreciated, a valve of the invention could be of the screw-down type, eg where the actuating means generally referred to above comprises a rotatable spindle, of the rising or non-rising type, co-operable with the sleeve; and, of course, it could, for example, be electrically or fluid, rather than manually, operated, eg in the nature of a solenoid or air-operated valve.

In conclusion, the invention, especially in the form specifically described with reference to the drawings, provides a simple and reliable device which does not suffer to the same extent from the seal wear problems associated with conventional valves that utilise washer or 0-ring seals. Also, whilst we refer above to application of a valve of the invention especially to the field of beverage dispensing, it will be understood that such a valve could find application in a variety of other fields, whether it be for controlling the flow of liquids or gases.

Claims

CLAIMS:

1. A fluid flow control valve comprising a body having a bore therein and a fluid inlet and a fluid outlet in communication with the bore, and a flexible sleeve located longitudinally in the bore, the sleeve being deformable by actuating means between a valve-open position in which there is defined between the bore wall(s) and the external surface(s) of the sleeve a fluid flow passageway interconnecting the inlet and outlet and a valve-closed position in which at least a portion of the sleeve externally is in circumferential sealing engagement with the bore wall(s) at a position intermediate the inlet and outlet thereby blocking the passageway.

2. A valve according to claim 1 wherein the sleeve is located coaxially within the bore.

3. A valve according to claim 1 or claim 2 wherein the bore is of substantially circular cross-section and wherein the sleeve is of generally circular cylindrical form.

4. A valve according to any one of claims 1 to 3 wherein the sleeve is a moulding in elastic material and comprises a bulged wall portion intermediate its ends, the wall portion, when the valve is in its closed position, sealingly engaging the bore wall thus closing the valve, and wherein the actuating means serves to transmit a stretching force to the sleeve to stretch the sleeve resiliently and longitudinally thereby causing the bulged wall portion to contract radially out of sealing engagement with the bore wall thus opening the valve.

5. A valve according to claim 4 wherein the sleeve will, by virtue of the tensile strain imparted it to it upon stretching thereof, resile back into the valve-closed position upon removal of the stretching force.

6. A valve according to any one of claims 1 to 5 wherein the actuating means comprises a piston extending within the sleeve.

7. A valve according to claim 6 when appendant to claim 5 wherein the piston is manually depressible in order to stretch the sleeve and thus open the valve.

8. A push-operated tap comprising a body having a bore of circular cross-section extending therein and, in communication with the bore, at axially spaced positions therealong, a fluid inlet and a fluid outlet and, coaxially mounted in the bore, a resilient tubular sleeve of substantially uniform wall thickness closed at one end thereof and open at the,other end thereof, the sleeve being secured to the body at its open end and having a bellowed wall portion at a position within the bore intermediate the inlet and outlet, the arrangement being such that tap is normally closed with the sleeve generally spaced from the bore wall but with the bellowed wall portion in circumferential sealing engagement with the bore wall thereby preventing the flow of fluid from the inlet to the outlet, the tap further comprising a piston extending into the sleeve through its open end and abutting its closed end such that, upon depression of the piston, the sleeve axially and resiliently stretches and the bellowed wall portion thereof contracts radially out of engagement with the bore wall thereby permitting fluid flow between the inlet and outlet via a generally annular passageway defined between the external surface of the sleeve and the bore wall, the sleeve resiling back to its normal, tap-closed, position, together with the piston, upon removal of the depressive force applied to the piston.

9. A fluid flow control valve substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.