Abstract: An assembly and method for determining the level of sound absorbing solids in a fluid-filled vessel. A number of sound receivers are mounted at spaced vertical positions to the exterior of the vessel along a generally vertical line, and a sound generator is mounted atop the vessel approximately 180.degree. around the circumference of the vessel from the receivers. The sound waves are intermittently or cyclically generated by the sound generator, they are received by the receivers, and evaluated. For those receivers mounted below the level of the solids, the energy received will be low, while for those mounted above the solids level in the fluid phase of the vessel, the energy received will be high. For cellulosic chips, the receivers are tuned to respond primarily to sound at a frequency of about 3200 Hz.

Abstract: In an apparatus for treating cellulose pulp with oxygen gas by passing the pulp and oxygen gas through a reaction vessel at elevated temperature and pressure, the improvement whereby the exothermic heat of reaction is controlled and the temperature of the pulp being treated is maintained below the point where the pulp would be degraded, the improvement comprising means for withdrawing oxygen gas from the vessel after the gas has been in contact with the pulp, dividing the withdrawn gas into two portions, cooling one of the portions to remove water vapor therefrom, recombining the gas portions whereby the resulting gas has a lower temperature than the gas withdrawn from the vessel and returning the resulting gas to the vessel for further contact with pulp therein, the amount of gas withdrawn from the vessel and the degree of cooling of the cooled portion of withdrawn gas being regulated to maintain the temperature within the vessel below the point where the pulp is degraded.

Abstract: A diverter valve assembly that diverts flowable material from an inlet to one of a plurality of outlets. An outer tubular housing has an inner element mounted therein for rotation with respect to the housing about a generally vertical axis of rotation. The inner element is in the shape of a truncated cone. An inlet is provided at the top of the housing and a plurality of outlets are spaced around the sides thereof. A diverter element is rigidly mounted to the inner element and extends through the open top of the inner element and through a side thereof -- 90.degree. from the open top -- to cooperate with one of the plurality of outlets. Outlet arm members extend through the housing and make sealing contact with the outer surface of the inner element. Rotation of the inner element to position in cooperation with a particular outlet allows the flow of flowable material through the housing inlet, through the diverter element, and through the particular outlet arm.