| 摘要 |
Sampling apparatus for collecting liquid samples of predetermined size from a source of liquid comprises a sample measuring container having liquid level detecting electrodes and a drain valve, a suction tube through which liquid is drawn from the source into the measuring container, a vacuum pump having a pressure port and a vacuum port, a multiposition control valve for selectively connecting either port to the measuring container, and electronic control means for operating the multiposition valve to connect the vacuum pump pressure port to the measuring container for a 5 second time interval after the vacuum pump is started so as to pressurize the measuring container and back-flush the suction tube (while the drain valve is closed) and for operating the multiposition valve to connect the vacuum pump vacuum port to the measuring container after the 5-second time interval to vacuumize the measuring container and draw in a sample of predetermined size, whereupon the electrodes detect this fact, the multiposition valve reconnects the vacuum pump pressure port to the measuring container to reflush the system for another 5-second time interval, and the pump stops and the drain valve reopens.
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