Gas inlet valve having a bellows drive

A gas inlet valve for the controlled inlet of a fluid into a vacuum process chamber, wherein the gas inlet valve comprises:

• a gas flow unit having a gas inlet, a gas outlet, and an inner volume connecting the gas inlet and the gas outlet, wherein the gas flow unit has a sealing surface in the inner volume,
• an adjustment unit projecting into the inner volume and having a valve disk which is arranged inside the inner volume, wherein the adjustment unit is movably mounted along an adjustment axis in the closing direction and in the opening direction,
• a drive unit which is coupled to the adjustment unit outside the gas flow unit and provides an adjustment of the adjustment unit along the adjustment axis, wherein the valve disk can be brought by means of the drive unit in the opening direction into an open position in which the valve disk is spaced from the sealing surface and a fluid flow is provided,
• a flexible sealing element which is connected to the gas flow unit and to the adjustment unit and atmospherically separates the drive unit from the inner volume,
• wherein
• the drive unit has an expansion element with a variable expansion volume, wherein a spatial expansion of the expansion element can be varied with a variation of the expansion volume,
• the drive unit has a compressed air channel connected to the expansion volume for pressurizing and expanding the expansion volume, and
• the gas inlet valve comprises a coupling unit which is connected to the drive unit and to the adjustment unit and arranged such that the coupling unit is moved upon variation of the expansion volume and causes movement of the adjustment unit.