A flow manostat for various purposes, including the candy test

The flow manostat described in tills paper is virtually a sensitive pressure-reducer in which the valve unit consists of a knife-edged circular orifice which is converted into an annular opening by means of a coaxial tapered core that floats upon a liquid surface which is depressed through contact with the gas at the regulated reduced pressure. Any change in the regulated pressure produces an axial movement of the core, thus expanding or contracting the area of the annular opening by an amount which is just sufficient to compensate approximately the effects of the change in the service pressure that induced the change in the regulated pressure. To minimize friction, the major diameter of the spindle or tapered part of the core is made slightly less than the diameter of the orifice. This allows the spindle to move its full length through the orifice without touching the edges of the orifice. Each valve unit has only a short range of variability in throughput capacity. Any reasonable capacity outside of this range can be obtained by substituting a valve unit of appropriate size in the same manostat. Each valve unit comprises an orifice plate with knife-edged opening (or else a pair of such plates), together with a properly fitting core having one spindle or two as required. The volume of flow always is governed by the discharge characteristics of the nozzle or fixed group of simultaneously operating nozzles served by the manostat. Any change in these characteristics will involve readjustment of the regulated pressure.