GB2037891A

GB2037891A - Oxygen-generating Apparatus

Info

Publication number: GB2037891A
Application number: GB7940333A
Authority: GB
Original assignee: Draegerwerk AG and Co KGaA
Current assignee: Draegerwerk AG and Co KGaA
Priority date: 1978-11-25
Filing date: 1979-11-21
Publication date: 1980-07-16
Also published as: NL7905749A; DE2851074A1; FR2442217A1; GB2037891B

Abstract

A chemical oxygen-generating apparatus has a container (2) provided with an outlet (10) and a chemical filling (3) capable of generating oxygen within the container (2). A sheet-form member (13) is secured to the container (2) to close off the outlet (10) and is deformable from an initial configuration under the influence of a predetermined pressure within the container (2). Puncturing means (17) for puncturing the sheet-form member (13) upon deformation is also provided. In use, the chemical filling (3) generates oxygen and the resultant increase in pressure in the container (2) deforms the sheet-form member (13) until it is punctured by the puncturing means (17), whereupon oxygen flows out through the outlet (10). The sheet-form member (10) provides a secure seal which, in use, is automatically punctured, thereby ensuring that no dangerous build-up of pressure occurs in the container (2). <IMAGE>

Description

SPECIFICATION Chemical Oxygen-generating Apparatus This invention relates to a chemical oxygengenerating apparatus which has a chemical filling capable of generating oxygen.

Known, chemical oxygen-generating apparatus contain in a housing a combustible material, for example a chlorate. After firing by means of a starting device, the material undergoes a thermal reaction and generates oxygen. The oxygen flows to a user in a prescribed manner. The kinetic energy for the oxygen flow is generated from the overpressure produced in the housing during the thermal reaction.

As a combustible material, a chlorate is sensitive to moisture. In this connection, small quantities of moisture result in inactivity, whereas greater quantities cause the material to fire. The housing of the apparatus must, therefore, be tightly sealed during storage. The housings and the necessary seals, for example the outlet for the oxygen, are to be designed such that, in the case of need, which is almost always a case of emergency, the user is not in any danger as a result of forgetting how to open it or as a result of a complicated opening operation. Furthermore, it must be ensured that the overpressure produced in the housing during the thermal reaction cannot become dangerous.

United States Patent Specifications Nos.

3,742,683 and 3,736,104, describe a chemical oxygen-generating apparatus which has several pressure-limiting valves in the housing in order to prevent excessive overpressure. One is arranged on an upper edge of the housing and connects an oxygen zone between the oxygen-generating compound and the inner housing with the exterior. A second connects the insulating area between inner- and outer-housings with the exterior and is arranged in the base of the outerhousing. A third pressure-limiting valve connects the insulating zone with the oxygen zone. No reference is made to the construction of the valves themselves. Basically, however, valves are provided with parts which must be movable for operation. It is questionable as to whether the valves will operate reliably after a long period of storage.No reference is made to the seal of the outlet for the oxygen, which is necessary for all chemical oxygen-generating apparatus.

Presumably, adhesive films are used here, as are known from other oxygen-generators. Film seals of this type do not necessarily guarantee a tight seal which may be required for years.

According to the present invention, there is provided a chemical oxygen-generating apparatus comprising a container provided with an outlet; a chemical filling within the container capable of generating oxygen; a sheet-form member which is secured to the container to close off the outlet and which is deformable from an initial configuration under the influence of a predetermined pressure within the container; and puncturing means for puncturing the sheet-form member upon deformation; the arrangement being such that, in use, when the chemical filling generates oxygen, the resultant pressure increase within the container deforms the sheet-form member until it is punctured by the puncturing means, whereupon oxygen flows out through the outlet.

Preferably the sheet-form member is normally curved and, in use, pressure within the container equal to or exceeding the predetermined pressure reverses the curvature of the sheet-form member to cause the sheet-form member to contact, and be punctured by, the puncturing means.

The seal in the form of a sheet-form member closing off the outlet provides a seal which both remains hermetically sealed over long periods of storage, and also enables a reliable opening of the outlet to be effected in a simple manner. With a curved sheet-form member, when the pressure in the container exceeds a predetermined value, the sheet-form member springs over to a position in which its curvature is reversed. The puncturing means then punctures the sheet-form member to release the oxygen.

The puncturing means can comprise a pointed projection secured to the container and projecting towards the sheet-form member. The pointed projection could comprise one corner of a substantially equilateral triangular flap.

Preferably, the substantially equilateral triangular flap is integral with an annular member secured to the container adjacent to, and co-axial with, the outlet, the flap being of an angle of approximately 1 300 relative to the annular member. The flap and the annular member can then conveniently be formed from a sheet of material.

The sheet-form member is preferably formed from Chrome-Nickel-Steel sheet as such a steel retains its bending strength and other resilient properties for a number of years.

The outlet and the puncturing means are preferably provided in a base of the container, for example, in a dished base member of the container secured within a main cylindrical casing of the container.

For a better understanding of the present invention and to show more clearly how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 shows a vertical section through a chemical oxygen-generating apparatus according to the present invention; and Figure 2 shows a plan view of a flap and an annular member of the apparatus of Figure 1 on a larger scale.

A chemical oxygen-generating apparatus 1 contains a chlorate filling 3 in a container 2. A pyrotechnical starting device 4 included in the oxygen-generating apparatus 1 has a firing pin 5 for striking a percussion cap 6, thereby firing the chlorate filling 3 by way of a starting powder 7.

Alternatively, the oxygen-generating apparatus 1 can also be equipped with a starting device using water.

A base 8 of the housing 2 defines an oxygen zone 9 between the base 8 and the chlorate filling 3.

An outlet 10 for oxygen is provided in the base 8. A seal 11 in the form of a curved plate 13 is disposed upstream of the outlet 10 (in terms of the intended flow direction of oxygen) and in the oxygen zone 9. The curved plate 1 3 is formed from a Chrome-Nickel-Steel. A convex side of the curved plate 1 3 projects into the oxygen zone 9.

The concave side is subject to atmospheric pressure via an opening 14 defined by an outlet 10. A pointed projection 1 7 projects into a position 1 6 into which the curved plate 1 3 can be urged. The pointed projection 1 7 comprises one corner of an equilateral-triangular flap 1 8 which is at an angle of approximately 1 30O relative to a mounting flange 19 with which the triangular flat 18 is integral. The mounting flange 1 9 is annular member (see Figure 2).

In use, the chemical oxygen-generating apparatus 1 is activated by striking the firing pin 5 which thenfires the percussion cap 6. The percussion cap 6, in turn, fires the chlorate filling 3 via the starting powder 7. The chemical filling 3 then produces oxygen which increases the pressure within the container 2. When this pressure reaches or exceeds a predetermined value, the curved plate 13 is urged from the position shown into the position 1 6 shown by dotted lines. The plate 1 3 can be such that it slowly moves between the two positions shown as the pressure increases or such that it instantaneousiy switches from its first position to the position 1 6 when the pressure exceeds or equals the predetermined value. In either case, when the plate 1 3 reaches the position 1 6 it is punctured by the pointed projection 1 7 to release the oxygen in the container 2, which oxygen is then free to flow through the outlet 1 0.

Claims

1. A chemical oxygen-generating apparatus comprising a container provided with an outlet; a chamical filling within the container capable of generating oxygen; a sheet-form member which is secured to the container to close off the outlet and which is deformable from an initial configuration under the influence of a predetermined pressure within the container; and puncturing means for puncturing the sheet-form member upon deformation; the arrangement being such that, in use, when the chemical filling generates oxygen, the resultant pressure increase within the container deforms the sheet-form member until it is punctured by the puncturing means, whereupon oxygen flows out through the outlet.

2. A chemical oxygen-generating apparatus as claimed in claim 1, wherein the sheet-form member isnormally curved and, in use, pressure within the container equal to or exceeding the predetermined pressure reverses the curvature of the sheet-form member to cause the sheet-form member to contact, and be punctured by, the puncturing means.

3. A chemical oxygen-generating apparrtus as claimed in claim 1 or 2, wherein the puncturing means comprises a pointed projection secured to the container and projecting towards the sheetform member.

4. A chemical oxygen-generating apparatus as claimed in claim 3, wherein the pointed projection comprises one corner of a substantially equilateral-triangular flap.

5. A chemical oxygen-generating apparatus as claimed in claim 4, wherein the substantially equilateral-triangular flap is integral with an annular member secured to the container adjacent to, and coaxial with, the outlet, the flap being at an angle of approximately 1 30C relative to the annular member.

6. A chemical oxygen-generating apparatus as claimed in claim 4 or 5 wherein the sheet-form member is formed from Chrome-Nickel-Steel sheet.

7. A chemical oxygen-generating apparatus as claimed in any preceding claim, wherein the outlet and the puncturing means are provided in a base of the container.

8. A chemical oxygen-generating apparatus as claimed in claim 7, wherein the sheet-form member and the puncturing means are provided in a dished base member of the container secured within a main cylindrical casing of the container.

9. A chemical oxygen-generating apparatus substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.