GB2141177A - Burster discs - Google Patents

Abstract

A burster disc for use in releasing pressure on one side thereof, when the initially higher pressure acting on the other side thereof drops below a predetermined level. Such a burster disc can be used to release the second stage pressure of a two- stage rocket motor when the first stage is depleted. The valve comprises a domed obturator portion (12) with radial scores (14), a gully (11) surrounding the obturator portion (12), an anchoring rim (10) surrounding the gully, and a backing ring having a base substantially equal to the internal diameter of the obturator portion. The base of the gully is adjacent the backing ring and the gully is composed of a ring having straight sections joining the outer ends of the radial scores. <IMAGE>

Description

SPECIFICATION Improvements in burster valves The present invention relates to burster valves, that is closures for use with pressurised fluids and arranged to open under a predetermined relative pressure.

A typical burster valve comprises a sheet of metal scored radially from a centre of pressure, whereby in operation when the burster valve is subject to a predetermined relative pressure it bursts at the scores and petals open.

The present invention provides a burster valve adapted to resist a high fluid pressure in one direction but to open when that pressure falls significantly below a lower fluid pressure in the other direction.

A burster valve according to the present invention comprises a sheet of material having a peripheral anchoring rim, an annular gulley surrounded by the rim and an obturator portion within the gully, the obturator portion being domed and on the convex surface thereof scored radially from the centre thereof to the gulley, and the gully being substantially straight between each score and adjacent the convex side of the obdurator portion.

Preferably the obturator portion is substantially hemispherical. The number of radial scores preferred will increase with size.

The burster valve may aiso comprise a backing ring having a bore substantially equal to the internal diameter of the obturator portion, and adapted to support the valve against pressure on the convex surface of the obturator portion. The backing ring may be attached to the rim of the valve.

The burster valve is preferably made of metal sheet.

A principal use of burster valves in accordance with the invention is in two stage rocket motors, between the stages. The valve can be arranged to resist the pressure of the first stage until this drops to a predetermined level, when it bursts under pressure from the second stage which then vents through the first. A particular advantage afforded by a burster valve in accordance with the invention is minimal manufacture cost.

A burster valve in accordance with the present invention will now be described by way of example with reference to the accompanying drawings, of which: Figure 1 is a plan view of the valve, and Figure 2 is a section on ll-ll in Fig. 1.

As shown in the drawings the burster valve comprises a sheet of metal in disc form having a peripheral anchoring rim 10, an annular gully 11 within the rim, and an obturator portion 1 2 within the gully, and a metal backing ring 1 3.

The obturator portion 1 2 is substantially hemispherically domed, with the convex surface scored, as at 14, in six lines extending equiangularly from the centre of the dome radially to the gully 11, which is straight between adjacent scores.

The backing ring 1:$ has the same bore as the obturator dome, and extends to the rim outer edge, to which it is brazed. It is not attached in the region of the gully 11 or the base of the dome 12.

In use of such a burster valve in a typical 2stage rocket, the valve is subject at first to an external pressure of 220 bars from the first stage and an internal pressure of 75 bars from the second. The external pressure on the obturator 1 2 is mainly reacted by the backing ring 1 3. When the first stage is substantially exhausted and the pressure therein attenuated, the obturator bursts at the scores 14 under the pressure from the second stage.

The segments thereof petal outwards, hinging about the base of the gully 11.

A typical disc of the type described has a bore of 100 mm. Discs with larger bores would preferably have a larger number of segments. For example, a disc with a 250 mm base may have 1 2 segments.

1. A burster disc comprising a sheet of material having a peripheral anchoring rim, an annular gully surrounded by the ring, and an obturator portion within the gully, the obturator portion being domed and on the convex surface thereof scored radially from the centre thereof to the gully, and the gully being substantially straight between each score and adjacent the convex side of the obturator portion.

2. A burster disc as claimed in claim 1 and wherein the obturator portion is substantially hemispherical.

3. A burster disc as claimed in claim 1 or claim 2 and comprising also a backing ring having a bore substantially equal to the internal diameter of the obturator portion, and adapted to support the valve against pressure on the convex surface of the obturator portion.

4. A burster disc as claimed in claim 3 and wherein the backing ring is attached to the rim of the valve.

5. A burster disc as claimed in any one of claims 1 to 4 and carrying six radial scores so that the gully is right hexagonal in configuration.

6. A burster disc as claimed in any one of the previous claims and made of metal.

7. A multistage rocket incorporating a burster valve as claimed in any one of the preceding claims between the stages.

8. A burster valve substantially as hereinbefore described with reference to the accompanying drawings.

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

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in burster valves The present invention relates to burster valves, that is closures for use with pressurised fluids and arranged to open under a predetermined relative pressure. A typical burster valve comprises a sheet of metal scored radially from a centre of pressure, whereby in operation when the burster valve is subject to a predetermined relative pressure it bursts at the scores and petals open. The present invention provides a burster valve adapted to resist a high fluid pressure in one direction but to open when that pressure falls significantly below a lower fluid pressure in the other direction. A burster valve according to the present invention comprises a sheet of material having a peripheral anchoring rim, an annular gulley surrounded by the rim and an obturator portion within the gully, the obturator portion being domed and on the convex surface thereof scored radially from the centre thereof to the gulley, and the gully being substantially straight between each score and adjacent the convex side of the obdurator portion. Preferably the obturator portion is substantially hemispherical. The number of radial scores preferred will increase with size. The burster valve may aiso comprise a backing ring having a bore substantially equal to the internal diameter of the obturator portion, and adapted to support the valve against pressure on the convex surface of the obturator portion. The backing ring may be attached to the rim of the valve. The burster valve is preferably made of metal sheet. A principal use of burster valves in accordance with the invention is in two stage rocket motors, between the stages. The valve can be arranged to resist the pressure of the first stage until this drops to a predetermined level, when it bursts under pressure from the second stage which then vents through the first. A particular advantage afforded by a burster valve in accordance with the invention is minimal manufacture cost. A burster valve in accordance with the present invention will now be described by way of example with reference to the accompanying drawings, of which: Figure 1 is a plan view of the valve, and Figure 2 is a section on ll-ll in Fig. 1. As shown in the drawings the burster valve comprises a sheet of metal in disc form having a peripheral anchoring rim 10, an annular gully 11 within the rim, and an obturator portion 1 2 within the gully, and a metal backing ring 1 3. The obturator portion 1 2 is substantially hemispherically domed, with the convex surface scored, as at 14, in six lines extending equiangularly from the centre of the dome radially to the gully 11, which is straight between adjacent scores. The backing ring 1:$ has the same bore as the obturator dome, and extends to the rim outer edge, to which it is brazed. It is not attached in the region of the gully 11 or the base of the dome 12. In use of such a burster valve in a typical 2stage rocket, the valve is subject at first to an external pressure of 220 bars from the first stage and an internal pressure of 75 bars from the second. The external pressure on the obturator 1 2 is mainly reacted by the backing ring 1 3. When the first stage is substantially exhausted and the pressure therein attenuated, the obturator bursts at the scores 14 under the pressure from the second stage. The segments thereof petal outwards, hinging about the base of the gully 11. A typical disc of the type described has a bore of 100 mm. Discs with larger bores would preferably have a larger number of segments. For example, a disc with a 250 mm base may have 1 2 segments. CLAIMS

1. A burster disc comprising a sheet of material having a peripheral anchoring rim, an annular gully surrounded by the ring, and an obturator portion within the gully, the obturator portion being domed and on the convex surface thereof scored radially from the centre thereof to the gully, and the gully being substantially straight between each score and adjacent the convex side of the obturator portion.

2. A burster disc as claimed in claim 1 and wherein the obturator portion is substantially hemispherical.

3. A burster disc as claimed in claim 1 or claim 2 and comprising also a backing ring having a bore substantially equal to the internal diameter of the obturator portion, and adapted to support the valve against pressure on the convex surface of the obturator portion.

4. A burster disc as claimed in claim 3 and wherein the backing ring is attached to the rim of the valve.

5. A burster disc as claimed in any one of claims 1 to 4 and carrying six radial scores so that the gully is right hexagonal in configuration.

6. A burster disc as claimed in any one of the previous claims and made of metal.

7. A multistage rocket incorporating a burster valve as claimed in any one of the preceding claims between the stages.

8. A burster valve substantially as hereinbefore described with reference to the accompanying drawings.