| 摘要 |
A switch-over device which is useful for a gas insufflation device using liquid gas includes at least two inflow channels each blockable by a valve and at least one outflow channel for alternate removal of a fluid medium from a plurality of containers. The device has a switch-over piston movably mounted in a housing and comprising a base member which has at each end a valve closure member in a form of a body of rotation. The switch-over piston is driven by a pressure difference between the fluid media and connects one of the inflow channels to the outflow channel in each of two switching positions. A working chamber accommodates the switch-over piston, with sealing elements being provided for closing off the inflow channels in a pressure tight manner when the switch-over piston is in the correspondingly closed position and for dividing the working chamber into two portions sealed off from each other. The switch-over piston and/or the working chamber is constructed so that at least one sealing element can be arranged selectively in different positions. The size of the areas of the switch-over piston which are acted upon by the fluid media and determined the switch-over point is determined by the position of the sealing element. |
