Gas leak detection device and method for same

A gas leak detection device, comprising:

• a fuel gas supply source;
• a main valve that shuts down a fuel gas from said fuel gas supply source;
• a shutdown valve provided in a fuel gas supply channel downstream of said main valve;
• a plurality of pressure monitoring means that each operate within a different predetermined pressure range and monitor a pressure in said fuel gas supply channel between said main valve and said shutdown valve;
• depressurization treatment means that depressurizes the inside of said fuel gas supply channel;
• and
• determination means that monitors a variation of pressure in a sealed space of said fuel gas supply channel formed between said main valve and said shutdown valve after said main valve and said shutdown valve have been closed and determines an operation state of said main valve based on the variation of pressure in said sealed space, wherein
• in said depressurization treatment, said fuel gas supply channel is depressurized until the pressure enters the predetermined pressure range in which the pressure can be monitored in said plurality of pressure monitoring means.

A gas leak detection method for a fuel cell system comprising a main valve in a fuel gas supply source, comprising the steps of:

• closing said main valve, while conducting a depressurization treatment of the downstream side of a fuel gas supply channel;
• closing a shutdown valve provided in said fuel gas supply channel, while conducting the depressurization treatment of the downstream side;
• monitoring via a plurality of monitoring devices that each operate within a different predetermined pressure range a variation of pressure in a sealed space of said fuel gas supply channel formed between said main valve and said shutdown valve, after said main valve and said shutdown valve have been closed;
• and determining an operation state of said main valve based on a variation of pressure in said sealed space, wherein
• in the step of closing said shutdown valve, said shut down valve is shut down when said sealed space is depressurized until the pressure enters the predetermined pressure range in which the pressure can be detected in the plurality of pressure monitoring devices for detecting a pressure in said sealed space.