GB2076123A - A hose check valve - Google Patents

Abstract

A hose check valve comprises a first component (1) having a tubular portion (3) and a nut portion (4), and a second component (2) having a body portion defining a chamber (9) and an extension portion with a passage (10), the body portion being accommodated within the tubular portion of the first component, a valve seat (11) being provided intermediate the gas inlet passage and the chamber, a valve element (20) being accommodated in the chamber, resilient means (28) also being accommodated in the chamber and biassing the valve element towards the valve seat, characterized in that a nipple (20) is attached to the free end of the body portion of the second component, the nipple having a groove (25) extending longitudinally and radially from the mouth thereof, the free end of the body portion of the second component having a lip which is engaged within the groove and deformed by its engagement within the groove to hold the nipple onto the body portion of the second component, the nipple retaining the resilient means within the chamber and, in use of the hose check valve, being held in sealing engagement with an appliance or a connector therefor. <IMAGE>

Description

SPECIFICATION A hose check valve The present invention relates to a hose check valve.

Hose check valves, in use, are fitted between a flexible hose connected through a regulator to a tap on a gas cylinder, e.g. an acetylene cylinder, and connected to a blowpipe or other appliance.

The hose check valve serves two purposes. Firstly, it is normal practice to turn off the taps on the blowpipe or other appliance, and then turn off the tap on the cylinder but this leaves the flexible hose full of gas and if the blowpipe or appliance is disconnected the gas escapes and may build up dangerously in the atmosphere. The hose check valve prevents such a build-up by remaining closed when the pressure in the hose slightly exceeds atmospheric pressure thereby preventing gas leaking from the flexible hose and escaping into the atmosphere. Secondly, the hose check valve prevents a backfire at the blowpipe or other appliance travelling back to the regulator and cylinder by closing in response to the backfire entering the valve. The hose check valve also prevents backfeeding or the reverse flow of gases.

Known hose check valves comprise a first component having a casing portion and an extension portion and a second component having a body portion and an extension portion. The body portion of the second component defines a chamber and is accommodated within the casing portion of the first component. A gas inlet passage extends through the extension portion of the second component and a gas outlet passage extends through the extension portion of the first component. A valve seat is provided intermediate the chamber and the inlet passage. A valve element is accommodated within the chamber and resilient means also accommodated in the chamber biases the valve element towards the valve seat to seat thereon, thereby to close communication between the chamber and said inlet passage.The valve element is held unseated from the valve seat when the gas pressure upstream thereof exceeds that downstream thereof by a small predetermined amount to allow communication between the chamber and the inlet passage.

In use of the hose check valve, the extension portion of the second component is connected to a hose and thence through a regulator to the tap of a gas cylinder and the extension portion of the first component is connected to a blowpipe or other appliance.

The extension portion of the first component is provided with a captive nut for securing that portion to a blowpipe or other appliance.

A disadvantage of known hose check valves is that the valve element and/or the resilient means may be accidently lost, thereby preventing proper functioning of the valve in use.

In one embodiment of the hose check valve the captive nut is held onto the extension portion of the first component by a circlip or split washer located in an annular groove in that component. A disadvantage of this embodiment is that the circlip or split washer may become accidentally dislodged from the groove enabling the nut to come off the extension portion of the first component.

The present invention aims at overcoming or mitigating the above-described disadvantages.

In accordance with the present invention, there is provided a hose check valve comprising a first component having a tubular portion and a nut portion, a second component having a body portion defining a chamber and an extension portion, the body portion being accommodated within the tubular portion of the first component, a gas inlet passage extending through the extension portion of the second component to the chamber, a valve seat being provided intermediate the gas inlet passage and the chamber, a valve element being accommodated in the chamber, resilient means also being accommodated in the chamber and biassing the valve element towards the valve seat to seat thereon to thereby close communication between the chamber and the inlet passage, the valve element being held unseated from the valve seat when the gas pressure upstream thereof exceeds that downstream thereof by a small predetermined amount, and a nipple attached to the free end of the body portion of the second component, the nipple having a groove extending longitudinally and radially from the mouth thereof, the free end of the body portion of the second component having a lip which is engaged within the groove and deformed by its engagement within the groove to hold the nipple onto the body portion of the second component, the nipple retaining the resilient means within the chamber. In use of the hose check valve, the nipple is held by the nut portion in sealing engagement with an appliance or a connector for the appliance.

It is intended that in use of the hose check valve according to the invention, the extension portion of the second component is connected to a hose and thence through a regulator to the tap of a gas cylinder and the other extension portion is connected to a blowpipe or other appliance (or to a connector for such an appliance).

The invention is further described below by way of example with reference to the accompanying drawings, in which: Figure 1 is a longitudinal view of the component parts of a hose check valve according to the invention; Figure 2 is a sectional view of the hose connection end of the hose check valve of Figure 1 before assembly of the valve; Figure 3 is a longitudinal sectional view of the hose check valve; Figure 4 is a front view of the valve element of the hose check valve; Figure 5 is a longitudinal sectional view of the nipple of the hose check valve; Figure 6 is a side view of an alternative valve element for the valve.

Referring to the drawings, the hose check valve shown therein comprises a first part 1 known as the loose nut end and a second part 2 known as the hose connection end.

The loose nut end 1 consists of a tubular portion 3 and a nut portion 4. The tubular portion 3 is formed with an internal annular groove 5 adjacent its free end. The nut portion 4 is hexagonal in external cross section and is internally threaded.

The hose connection and 2 consists of a tubular extension portion 7 and a substantially cylindrical body portion 8, the body portion defining a chamber 9, the bore 10 of the tubular portion being arranged to communicate with the chamber.

A valve seat 11 formed by an annular flat surface is provided.

The free end of the body portion 8 is formed as an annular lip 12. Adjacent its free end, the body portion 8 has an external annular rib 30.

The valve further comprises a nipple 13 which has a through bore 14, an annular rib 16, a rounded end portion 17 and tubular portions 18 and 1 9. An annular groove 25 is defined between the rib 1 6 and the portion 1 8. The groove extends longitudinally and radically inwardly from its mouth towards rounded end portion 17. Thus the internal and external diameters of the groove (measured respective from its radically inner surface and its outer surface) decreased in the longitudinal direction away from its mouth.

Within the chamber 9 is accommodated a valve element 20 formed with a head 21 and a boss 22.

The head 21 has a flat face remote from the boss 22 and in which is formed an annular groove accommodating an annular sealing ring 23.

A coil spring 28 encircles the boss 22 of the valve element 20 and the portion 19 of the nipple 12.

In assembling the valve, the hose connection end 2 is inserted into the loose nut end 1 until the rib 30 abuts a surface 32 of the loose nut end. The free end of the tubular portion 3 of the loose nut end is then deformed from the state shown in the lower part of Figure 3 to enter an external annular groove 33 in the hose connection end as shown in the upper part of Figure 3, the loose nut end 1 remaining rotatable relative to the hose connection end 2. The valve element 20, with the sealing ring 23 inserted into the groove in its head 21, is inserted into the chamber 9 of the hose connection end. The coil spring 28 and the portions 18 and 19 of the nipple 13 are also inserted into the chamber 9, the spring encircling the boss 22 of the valve element 20 and the portion 19 of the nipple.

The nipple 1 3 is pressed hard against the hose connection end 2 causing the lip 12 to enter the groove 25 and to be deformed to the state shown in Figure 3. The lip 12 is thus deformed radially inwardly and serves to prevent the nipple becoming dislocated from the loose nut end 2.

The spring 23 biases the valve element 20 to seat upon the valve seat 11 to close communication between the bores 10 and 14.

In use, the nut portion 4 is screwed to a blowpipe or other appliance or to a connector for such an appliance to attach the hose check valve to the blowpipe or appliance, the rounded end portion 1 7 of the nipple 1 3 sealingly engaging in a conical seat of the appliance or the connector, the bore 14 of the nipple opening into a corresponding inlet bore of the appliance or the connector. The tubular portion 7 is inserted into a flexible hose in which the enlarged end portion 23 tightly fits, to attach the valve to the hose. A standard hose clip is then normally fitted to the hose to prevent the hose puliing off. The hose is connected through a regulator to a tap of a gas cylinder (not shown).

When the tap of the gas cylinder is turned on the pressure of gas in the hose lifts the valve element 20 from the valve seat 11 thereby opening the valve and allowing gas to flow through the valve from the gas cylinder through the regulator to the blowpipe or other appliance.

When the tap is turned off, pressure upstream and downstream of the valve element should be equal, and the sealing ring 23 of the valve element should seat on the valve seat 11 under the action of the spring 23, the valve thus being closed. The valve remains closed even if, as frequently occurs, the blowpipe or appliance is disconnected, the gas remaining in the flexible hose being prevented from escaping into the atmosphere, as the valve element remains seated on the valve seat under the action of the spring 23 and thus gas is prevented from passing through the valve and thence into the atmosphere.

If when the tap has been turned on, a backfire occurs, the backfire will travel through the blowpipe to the valve. An abrupt rise in pressure occurs at and immediately in front of the backfiring gas. Thus just before the backfire reaches the valve element 20, a sharp pressure differential will rise across the valve element and will drive the valve element against the valve seat 11 thereby closing communication between the chamber 9 and the bore 10 of the hose connection end and preventing the backfire travelling to the cylinder.

As shown in Figure 4, the head 21 of the valve element 20 is substantially square in cross section. This provides adequate space between the side faces of the head 21 and the internal surface of the tubular portion 8 to allow flow of gas pass the valve element 20 when unseated from the valve seat 11.

A filter may be incorporated into the valve, e.g.

within the chamber 9 or the bore 10 to prevent ingress of foreign matter into the valve when disconnected either from the appliance or from the gas cylinder.

The valve element 20 may be of the form shown in Figure 6. As shown in Figure 6, the valve element 20 comprises a base portion 30 and a projection 31 which is shaped to retain a sealing ring 23 (indicated in section by broken lines).

Claims (8)

1..A hose check valve comprising a first component having a tubular portion and a nut portion, and a second component having a body portion defining a chamber and an extension portion, the body portion being accommodated within the tubular portion of the first component, a gas inlet passage extending through the extension portion of the second component to the chamber, a valve seat being provided intermediate the gas inlet passage and the chamber, a valve element being accommodated in the chamber, resilient means also being accommodated in the chamber and biassing the valve element towards the valve seat to seat thereon thereby to close communication between the chamber and the inlet passage, the valve element being held unseated from the valve seat when the gas pressure upstream thereof exceeds that downstream thereof by a predetermined amount, characterized in that a nipple is attached to the free end of the body portion of the second component, the nipple having a groove extending longitudinally and radially from the mouth thereof, the free end of the body portion of the second component having a lip which is engaged within the groove and deformed by its engagement within the groove to hold the nipple onto the body portion of the second component, the nipple retaining the resilient means within the chamber and, in use of the hose check valve, being held in sealing engagement with an appliance or a connector therefor.

2. A hose check valve according to claim 1, wherein said groove tapers in cross section away from the mouth thereof.

3. A hose check valve according to either preceding claim, wherein the groove extends longitudinally and radially inwardly from the mouth thereof.

4. A hose check valve according to any preceding claim, wherein the lip is engaged with the groove by pressing the nipple hard against the lip to cause the lip to enter the groove and be deformed.

5. A hose check valve according to any preceding claim, wherein the nipple has an annular rib and a tubular portion between which the groove is provided.

6. A hose check valve according to claim 5, wherein the tubular portion of the nipple is located in the chamber of the second component and the body portion of the second component has an annular rib which engages with the annular rib of the nipple.

7. A hose check valve according to any preceding claim, wherein the tubular portion of the first component has a deformation engaged in an external groove in the second component, whereby the first component is rotatably held attached to the second component.

8. A hose check valve substantially as described herein with reference to and as illustrated in the accompanying drawings.