A gas valve unit and a method of performing a pressure test to a gas valve unit

A method of performing a pressure test to a gas valve unit having an enclosure provided with an inlet and an outlet, wherein the inlet and the outlet have an inner pipe and an outer pipe, wherein the inner pipe is arranged to extend from the inlet to the outlet via the enclosure forming a continuous gas tight internal piping inside the enclosure, and the outer pipe is arranged to open into the enclosure via at least one opening, and wherein walls of the inner pipe and the outer pipe form a space there between, which space is a first volume, and the enclosure forms a space inside as a second volume, and wherein the first volume and the second volume are arrangeable in flow communication with each other via the at least one opening in connection with the outer pipe, and wherein at least one blocking unit is configured for selectively blocking and unblocking the at least one opening in connection with the outer pipe, the method comprising:

• coupling the gas valve unit with a piping of its installation site, and blocking flow communication between the first volume and the second volume with the at least one blocking unit;
• pressurizing the first volume, and maintaining pressure in the first volume over a predetermined period of time while the second volume is at an initial pressure and separated from the first volume;
• releasing, after a successful pressure test, the pressure from the first volume;
• and
• unblocking the flow communication between the first volume and the second volume inside the enclosure.

A method of assembling and pressure testing a gas valve unit for a gas consumer in a marine vessel, the method comprising:

• providing a gas tight enclosure forming a space inside thereof and arranging an inlet and an outlet to the enclosure, wherein the inlet and outlet have a pipe, into which pipe at least one opening is arranged to open into the enclosure;
• pressure testing the space inside the enclosure and the inlet and the outlet, using liquid;
• providing an internal piping for extending between the inlet and an outlet in the enclosure;
• pressure testing the internal piping using liquid;
• assembling a valve member and instruments to the internal piping;
• assembling the internal piping into the enclosure such that the piping extends inside the enclosure from the inlet to the outlet, and the internal piping is led through the inlet and the outlet, wherein a pipe of the internal piping forms an inner pipe and the pipe forms an outer pipe of the inlet and the outlet;
• pressure testing a first volume inside the enclosure and a second volume between the inner pipe and the outer pipe in the inlet and the outlet, using gas;
• coupling the gas valve unit with a piping of its installation site such that the inner pipe and the outer pipe are both coupled to the piping;
• blocking flow communication between the first volume and the second volume with at least one blocking unit configured and arranged for selectively blocking and unblocking the at least one opening in connection with the outer pipe;
• pressure testing the first volume while the second volume is at an initial pressure and separated from the first volume;
• after a successful pressure test, releasing pressure from the first volume;
• and
• unblocking the flow communication between the first volume and the second volume inside the enclosure with the at least one blocking unit.