| 摘要 |
To degas a fiber suspension (2), the pressure (pB) developed in the vessel (3) by the vacuum unit (4) is measured by at least one pressure transmitter (20.1). The dominant pressure (pA1) in the take-off channel (6.1) is measured by a further pressure transmitter (20.2). The actual level (22.1) is computed by a control (21) from the difference between the two pressure measurements, to be brought to the nominal level (22.2) by adjusting the feed pump (5) speed. To degas a fiber suspension, a further pressure transmitter (20.3) registers the dominant pressure (pA2) in the take-off channel, after the second transmitter in the flow direction (S), where the fiber suspension (2.2) is generally free of gas. The geodesic difference (UG) from the second transmitter is used by the control to set a density correction (DK) at the actual level in the vessel by the action of the vacuum unit, altering the speed of the feed pump and/or the stock inlet pump. Surplus fiber suspension at the vessel is taken by an overflow (18) for recirculation. An Independent claim is included for an assembly to degas a fiber suspension, with a vacuum unit connected to the suspension vessel, and pressure transmitters to measure the pressures. A control corrects the vessel level according to the measurements. Preferred Features: The vacuum unit has a vacuum pump (4.2) with a drive motor (23) operating at a controlled speed, and preferably an electromotor. A similar motor drives the feed pump and the stock inlet pump. A dividing wall (18.1) is at the overflow in the suspension vessel, to separate surplus suspension, to flow through an overflow channel (19) into the recirculating circuit.
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