Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
70 words
A valve member (1818') for a valve assembly of a respirator, the valve member having a disc (20,20) of elastomeric material with a peripheral portion (23,23') for sealing against a seat of the assembly and a central portion (24,24') for securing the member in the assembly, characterized in that there is an annular channel (25,25') in the disc surrounding the central portion (24,24') and radially inside the peripheral portion (23,23').
Claim 2
Dependent Claim
70 words
A valve member (1818') for a valve assembly of a respirator, the valve member having a disc (20,20) of elastomeric material with a peripheral portion (23,23') for sealing against a seat of the assembly and a central portion (24,24') for securing the member in the assembly, characterized in that there is an annular channel (25,25') in the disc surrounding the central portion (24,24') and radially inside the peripheral portion (23,23').
Claim 3
Dependent Claim
67 words
A valve member according to claim 1 wherein the peripheral portion terminates in a peripheral bead (23, 23') and the central portion (24,24') has a rear surface for positioning the central portion in relation to the valve assembly when secured therein, at least the peripheral portion being rearwardly dished so that the plane of the said bead (23,23') is substantially rearward of that of the rear surface.
Claim 4
Dependent Claim
19 words
A valve member according to claim 1 or claim 2 wherein the channel (25,25') is of substantially semi-toroidal section.
Claim 5
Dependent Claim
47 words
A valve member according to any one of the preceding claims wherein the radially inner edge (27,27') of the channel (25,25') terminates a surface of the central portion, the radially outer edge (26,26') of the channel lying in a plane forwardly of that containing the said surface.
Claim 6
Dependent Claim
30 words
A valve member according to any one of the preceding claims wherein the valve member (18,18') including its securing means (19,19') is formed integrally of one piece of elastomeric material.
Claim 7
Dependent Claim
93 words
A respirator having a valved gas outlet (2) and a a valved gas inlet (3,4), the valve assembly of at least the outlet or the inlet including a valve member (18,18') as claimed in any one of the preceding claims with its central portion (24,24') secured in the assembly and the peripheral portion (23,23') sealed against a seat thereof whereby to prevent gas flow in the non permitted direction but to suddenly lower the rate of increase of resistance to gas flow in the permitted direction, above a predetermined'value of rate of flow.
Claim 8
Dependent Claim
32 words
A respirator according to claim 6 wherein both of the valve assemblies have a said valve member, both the valve members being arranged with their channels (25,25') opening outwardly of the respirator.
Claim 9
Dependent Claim
78 words
- A respirator according to claim 6 or claim 7 wherein the securing of the member is by means of pulling through an orifice in the assembly a conical elastomeric stem (19,19') integral with the disc (20,20') and projecting rearwardly behind it to stretch the stem until a narrowing (21) of the stem adjacent the central portion of the disc registers with the orifice, whereby to pre-tension the disc (20,20') against the seat portion of the valve assembly.
Claim 10
Dependent Claim
35 words
A respirator according to claim 6, claim 7 or claim 8 wherein the valve member (18) of the outlet valve (2) is a diaphragm for a convolute speech transmitter passage (12) of the gas outlet.