Gas supply apparatus

Claim 1

A flow limiting device for fitment in a gas supply line comprising: a body part having a bore extending therethrough; a valve seat formed within said bore; a valve assembly located in said bore, said assembly moving axially in said bore in response to variations in the rate of flow of gas through said bore, said valve assembly including a valve head having an upstream end and a downstream end, a stem connected to said valve head, and a washer encircling said stem and abutting against said downstream end of said valve head, said valve head further including a peripheral skirt portion surrounding said washer, and wherein at least one generally radially extending slot is formed at the abutting surfaces of said valve head and said washer; and spring means surrounding a portion of said valve assembly for acting in opposition to the direction of flow of gas through said bore, said spring means acting to urge said valve assembly away from said valve seat; whereby the radially outer end of said at least one slot it shrouded by said peripheral skirt portion of said valve head, the arrangement being such that during normal flow of gas through the device said spring means prevents said valve head and said washer from contacting said valve seat so that the flow of gas is unimpeded, and during an excessive flow of gas said valve assembly is displaced against the force of said spring means causing said washer to abut against said valve seat, and wherein a predeterminedly small quantity of gas is allowed to flow through the device by way of said at least one slot formed at the abutting surfaces of said valve head and said washer, said at least one slot tending to remain free of dust and other inclusions in the gas during normal flow by the fact that the gas is not caused to flow through said at least one slot during normal flow since said at least one slot is shrouded by said peripheral skirt portion of said valve head.