Patent ID: 8851053

Claim:
A gas fuel supply apparatus for supplying a gas fuel to a gas combustion apparatus, comprising: gas container attachment means for attaching thereto a plurality of gas containers that contain respective ones of a plurality of types of gas fuels having different working pressures, the plurality of gas containers attached to the gas container attachment means communicating with corresponding gas fuel supply passages so as to supply the gas fuels to the gas combustion apparatus via the corresponding gas fuel supply passages, the gas fuel supply passages including a first gas fuel supply passage for one of the gas fuels which has a low working pressure and a second gas fuel supply passage for other of the gas fuels which has a higher working pressure than the one gas fuel, the first gas fuel supply passage and the second gas fuel supply passage joining together at a position upstream of the gas combustion apparatus; switching means provided in the gas fuel supply passages, the gas fuel to be supplied to the gas combustion apparatus being switchable between the plurality of types of gas fuels via the switching means; the switching means comprising a first switching valve disposed in the first gas fuel supply passage and operable to open or close the first gas fuel supply passage and a second switching valve disposed in the second gas fuel supply passage and operable to open or close the second gas fuel supply passage, the first and second switching valves being operatively linked together such that when one of the first switching valve and the second switching valve is in an open position, the other of the first switching valve and the second switching valve is in a closed position, and when said one switching valve is disposed in a closed position, the other switching valve is in an open position; and a check valve provided in the first gas fuel supply passage, corresponding to the gas container that contains the gas fuel having the low working pressure, the check valve preventing the gas fuel having the higher working pressure from flowing from a downstream side of the check valve closer to the gas combustion apparatus to an upstream side of the check valve closer to the gas container attachment means.