Patent ID: 8627710

Claim:
A gas probe for sampling gas molecules from a fluid, said gas probe comprising; a probe housing with an orifice for entrance of said gas sample molecules from said fluid into an interior of said probe housing, and said gas probe being adapted to be arranged such that said interior of said probe housing is arranged in gas communication with a test gas sensor configured to detect test gas molecules among said gas sample molecules, a protecting member comprising a stack of layers, whereby said stack is arranged in said probe housing in a flow path for gas sample molecules from said orifice and further into said probe housing such that gas sample molecules are required to pass through all layers of said stack in order to pass further into said probe housing and in order to reach said test gas sensor, whereby gas sample molecules pass through said stack in a gas sample flow, and whereby said stack comprises, seen in a direction of said gas sample flow through said stack, at least a first membrane layer, a first spacer layer, a first filter layer and a second spacer layer, wherein said probe housing comprises an inlet for introducing blocking gas molecules into said second spacer layer and an outlet for discharging blocking gas molecules out of said first spacer layer, whereby said blocking gas molecules are required to pass through said first filter layer in a blocking gas flow being directed in a direction opposite to the direction of said gas sample flow in order to reach said outlet, and wherein said gas probe is connectable to a control unit for controlling the flow of blocking gas molecules into said second spacer layer through said inlet so as to control said blocking gas flow through said first filter layer in order to control said gas sample flow through said first filter layer.