Abstract: A jet velocity measuring apparatus is disclosed for measuring the velocity of a fluid stream. The apparatus (10) measures the time delay between primary electronic signals generated by a first photosensitive device (32) as a result of a first beam of light from a light source (34) being reflected by a portion of the surface (S) of the stream (24) and secondary electronic signals generated by a second photosensitive device (36) as a result of a second beam of light from a light source (38) being reflected downstream by substantially the same portion of the surface of the stream (24). The apparatus includes a housing (22) disposed parallel to the plane (P2) of the surface of the stream. A first and a second fiberoptic bundle (42, 44) transmit light from the light source (34, 38) to the surface of the stream (24) and back respectively to the photosensitive devices (32, 36). Debris-deflecting slots (88, 90) are disposed adjacent to the housing (22) for deflecting debris therefrom.

Abstract: A control system provides automatic control of winder deceleration and stopping to a preset sheet length, or preset roll diameter. The system utilizes a closed loop control of drive deceleration and automatic compensation for layers slabbed off following a sheetbreak.

Abstract: A stepper motor control circuit for a step motor and step motor control which has substantially higher efficiency than the motors and the control circuits of the prior art and which uses a chopper current control and phase control for each of the two phases of a two phase step motor and wherein each phase has two separate windings that are magnetically coupled together. The invention provides a three step switching sequence which produces different current paths in each step so that a higher operating efficiency is achieved than circuits in the prior art.

Abstract: 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.

Abstract: Objectionable noise is inhibited in sheet spreaders of the type wherein strips of a slit traveling web are laterally separated by running the strips over spaced, bowed hollow spreader bars, frictional resistance being alleviated by floating the strips on a layer of air covering the areas of the bars wrapped by the strips. Tendency toward high frequency vibration and thus noise experienced in high speed operation is inhibited by ventilation in the tangency angles between the bars and the running strips.