| 摘要 |
<p>Apparatus for attenuating low frequency pressure variations in a stock suspension being fed to a paper machine. The apparatus includes a pressurized overflow chamber having an inlet which delivers a stock suspension therein and an outlet for discharging stock from the chamber. A first control means controls the pressure applied to the suspension in the overflow chamber. The chamber communicates with a sump which receives the overflow from the overflow chamber. A sensing means senses the stock pressure in the inlet conduit and a second sensing means senses the level of stock in the sump. A high pass filter receives a signal from the first sensing means and a low pass filter receives a signal from the second sensing means. A summing amplifier receives the output of the high and low pass filters. A control means receives the output of the summing amplifier and is connected to the overflow means to control operation of an overflow valve in response to the output of the summing amplifier.</p> |
