GB2192692A - Bi-directional flow control device - Google Patents

Abstract

A Bi-Directional Flow control device consists of moveable portions 2A & 2B held in a particular position by a spring 3 within a housing forming part of a pressurised flow path, such that normal rates of flow of a gas or liquid, are achieved with little impediment in either direction. Should a rupture occur elsewhere in the flow path resulting in a hazardous loss of a substance, the resulting excess flow in either direction is sensed by the device 1, which then closes to prevent further loss thus minimising the hazard. This unit can be incorporated into any assembly, the hose fitting being a particular example. By operating when a predetermined excess flow occurs in any direction the unit cannot be fitted the wrong way round and by being an integral part of a hose assembly for example, cannot be omitted at any time, thus protecting personnel and equipment against component failures and human error. In a modification, flow in either direction is controlled by a single closure member 2 held between opposing seats by springs 3A, 3B. <IMAGE>

Description

SPECIFICATION Bi-directional flow fuse The device can be manufactured in a variety of forms, some of which are illustrated in Figs. A, B and C.

In Figs. A, B and C, the device (item 1) is shown to be integrally manufactured with a hose fitting, with the portion that attaches the hose to the fitting (item 4), and the portion that connects the hose assembly including the hose and coupling with the device (item 1) included to the next portion (item 6) of the fluid or gas system.

In all figures, there is a moveable portion (item 2) or portions (items 2A & 2B) normally held in a particular position by a spring (item 3) or springs (items 3A & 3B) or by an equivalent method.

The moveable portion or portions are so designed that fluids, gases or any multi-phase substance can pass over, through or around as appropriate, with only a nominal amount of resistance to flow being experienced at the normal rate of fluid flow.

Should any event, planned or otherwise, cause the flow rate to exceed the normal flow rate by a significant amount, then the magnitude of the resistance to flow substancially increases. At a predetermined flow condition, this increased resistance to flow results in a force on a moveable portion within the device which exceeds the positioning force of the positioning spring or springs within the device.

This causes the moveable portion to move in the direction of the fluid flow, causing it to further restrict the flow path until the moveable portion attains a predetermined seated or sealing position.

In the seated or sealed position, a pressure rated shut-off is provided, thus preventing an unwanted excess flow.

Included in the device as an option is a leakage path (item 7), which then allows such a device to re-open, when the cause of the excess flow has been removed, and does so by allowing a gradual equalisation in pressure across the moveable portion. As equalisition is almost achieved, the positioning spring or springs then cause the moveable portion to move back to the 'normal' position, thus allowing flow to resume if desired.

This device is particularly unique in that it is so designed to provide such a shut-off facility when the fluid flow direction is in either direction. By integrating the device into, for example, a hose fitting, it can be appreciated that regardless of the use to which the hose is put, it cannot be installed so that the flow direction is incorrect.

In a similar manner, such a device in a system which normally handles flow in both directions at different times, still provides a shut-off when excess flow is experienced regardless of direction of flow.

The device would conventionally provide a shut-off at the desired excess flow velocity in either direction. This can be altered by paying particular attention to such design parameters as the shaping of the moveable portion(s), the spring(s) or equivalent and the body of the device to provide various shut-off velocities at various pressures to be the same in both directions or different in both directions as required.

The envisaged application of this device is in hose type systems handling compressible or hazardous substances where the escape of such substances is likely to cause a hazard to life, by chemical attack or by indirect injury through slipping on a spillage or by the whip like movement of a compressed air line if ruptured.

Such a device can also be fitted to other than hose fittings to provide protection as described above and also to protect plant, equipment and instruementation which cannot accept a high flow rate, or to prevent an expensive loss of the substance being handled when a hose or a component fails or when the system is accidentally opened up or has a component removed.

1. This device provides a shut- off when excess flow of the substance within the system in either direction attains a predetermined limiting flow rate.

2. The device, by being bi-directional, as described in 1 above, avoids incorrect installation in a system thus ensuring the protection desired is always achieved.

3. The device, as described in 1 above, protects personnel in the vicinity of a component failure from a 'whipping' hose or from a large escape of a dangerous substance.

4. The device, in addition to 3 above protects machinery and instruements from high flow rates.

5. The device, in addition to 3 above, protects against sudden shock flows as when a valve is opened suddenly.

6. The device protects personnel and machinery as variously described above, when a component is or has been inadvertantly removed, resulting in a substance loss or a sudden flow which causes the device to close.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Bi-directional flow fuse The device can be manufactured in a variety of forms, some of which are illustrated in Figs. A, B and C. In Figs. A, B and C, the device (item 1) is shown to be integrally manufactured with a hose fitting, with the portion that attaches the hose to the fitting (item 4), and the portion that connects the hose assembly including the hose and coupling with the device (item 1) included to the next portion (item 6) of the fluid or gas system. In all figures, there is a moveable portion (item 2) or portions (items 2A & 2B) normally held in a particular position by a spring (item 3) or springs (items 3A & 3B) or by an equivalent method. The moveable portion or portions are so designed that fluids, gases or any multi-phase substance can pass over, through or around as appropriate, with only a nominal amount of resistance to flow being experienced at the normal rate of fluid flow. Should any event, planned or otherwise, cause the flow rate to exceed the normal flow rate by a significant amount, then the magnitude of the resistance to flow substancially increases. At a predetermined flow condition, this increased resistance to flow results in a force on a moveable portion within the device which exceeds the positioning force of the positioning spring or springs within the device. This causes the moveable portion to move in the direction of the fluid flow, causing it to further restrict the flow path until the moveable portion attains a predetermined seated or sealing position. In the seated or sealed position, a pressure rated shut-off is provided, thus preventing an unwanted excess flow. Included in the device as an option is a leakage path (item 7), which then allows such a device to re-open, when the cause of the excess flow has been removed, and does so by allowing a gradual equalisation in pressure across the moveable portion. As equalisition is almost achieved, the positioning spring or springs then cause the moveable portion to move back to the 'normal' position, thus allowing flow to resume if desired. This device is particularly unique in that it is so designed to provide such a shut-off facility when the fluid flow direction is in either direction. By integrating the device into, for example, a hose fitting, it can be appreciated that regardless of the use to which the hose is put, it cannot be installed so that the flow direction is incorrect. In a similar manner, such a device in a system which normally handles flow in both directions at different times, still provides a shut-off when excess flow is experienced regardless of direction of flow. The device would conventionally provide a shut-off at the desired excess flow velocity in either direction. This can be altered by paying particular attention to such design parameters as the shaping of the moveable portion(s), the spring(s) or equivalent and the body of the device to provide various shut-off velocities at various pressures to be the same in both directions or different in both directions as required. The envisaged application of this device is in hose type systems handling compressible or hazardous substances where the escape of such substances is likely to cause a hazard to life, by chemical attack or by indirect injury through slipping on a spillage or by the whip like movement of a compressed air line if ruptured. Such a device can also be fitted to other than hose fittings to provide protection as described above and also to protect plant, equipment and instruementation which cannot accept a high flow rate, or to prevent an expensive loss of the substance being handled when a hose or a component fails or when the system is accidentally opened up or has a component removed. CLAIMS

1. This device provides a shut- off when excess flow of the substance within the system in either direction attains a predetermined limiting flow rate.

2. The device, by being bi-directional, as described in 1 above, avoids incorrect installation in a system thus ensuring the protection desired is always achieved.

3. The device, as described in 1 above, protects personnel in the vicinity of a component failure from a 'whipping' hose or from a large escape of a dangerous substance.

4. The device, in addition to 3 above protects machinery and instruements from high flow rates.

5. The device, in addition to 3 above, protects against sudden shock flows as when a valve is opened suddenly.

6. The device protects personnel and machinery as variously described above, when a component is or has been inadvertantly removed, resulting in a substance loss or a sudden flow which causes the device to close.