| 摘要 |
Arrangement for control of an evacuation assembly, designed to evacuate gases, particles, etc., from a locally bounded work site, for example, the region around a welding tip, gluing tip, or similar device. At the work site the assembly has a suction mouthpiece, which is connected via a line to a suction blowing assembly. The line 3 is provided with a shutoff valve 10 for interrupting the flow from the suction mouthpiece 2. The valve comprises a valve body, for example, a piston slide valve 21, which can move between a closing position, in which the connection between the inlet side 22 of the valve, connected to the suction mouthpiece, and its outlet side, connected to the suction blowing assembly 4, is interrupted, and a position in which the connection is open. The valve body is connected for its movement to a pneumatic motor operated by the low pressure of the evacuation system, such as a membrane 24, which bounds an operating chamber 25 away from the atmosphere, so that a pressure difference between the chamber 25 and the atmosphere brings about a movement of the membrane 24 and thus a movement of the valve body 21, 31. The chamber communicates by a narrowing or vent channel 30 with the outlet side 23 of the valve 10, while at the same time the chamber 25 communicates with the atmosphere via a control line 11. When the control line is open, atmospheric pressure is applied to the chamber via the line, but when the control line 11 is closed, the pressure of the outlet side 23 is applied to the chamber, so that the valve body is shifted. <IMAGE> |
