Patent ID: 6981517

Claim:
A gas supply system for pulse-wise feeding a reactant gas to a reactor, the gas supply system comprising: a first valve being a four-port diaphragm valve having a first fluid passage between a first and a second port and a second fluid passage between a third and a fourth port, the fluid passages being separable and in communication with spaces adjacent to and at opposite sides of a valve seat, such that in a closed state of the first valve the fluid passages are separated and in an open state of the first valve said fluid passages are in communication with each other; a feed of reactant being connected to the first port; a feed of purge gas being connected to the second port; a feed of purge gas being connected to the third port; the fourth port being arranged for connection to said reactor; and a second valve which in an open state brings the first port into fluid communication with an exhaust and in a closed state closes off said fluid communication; wherein the gas supply system provides a reactant flow state in which the first valve is in an open state and the second valve is in a closed state so that reactant gas flows from the feed of reactant, via the first port and the fourth port to the reactor, and wherein the gas supply system provides a purge state in which the first valve is closed and the second valve is in a open state, so that purge gas flows from the second port via the first port to the exhaust and that purge gas flows from the third port via the fourth port to the reactor.