| 摘要 |
<p>Apparatus for selectively delivering measured quantities of liquid from a flowing channel to a storage vessel to produce a composite sample. A container is supplied with a continuous flow of liquid from the channel at a constant level. A dispensing tube has an inlet connected to receive air during vacuum, vent and pressure portions of an operation cycle and an outlet connected to deliver a sample to a recipient system. An air pump has an output connected to supply air under pressure through one conduit to the air lift tube which supplies the liquid from the channel and through a branch conduit to the inlet of the dispensing tube. A transfer vessel operatively connected between the inlet and outlet of the dispensing tube receives liquid from the container during the vacuum portion of the operation cycle at a level above that of the liquid remaining in the dispensing tube from a previous operation cycle. A vacuum regulator unit is operatively connected to the air pump inlet to regulate the vacuum to the dispensing tube and a pressure regulator is operatively connected to the branch conduit to regulate the pressure to the dispensing tubes. Valves responsive to a programmer operate to selectively control the flow of air from the air pump to the dispensing tube during an operation cycle.</p> |
