Abstract: There is provided between a concentrate tank and a membrane filter a circulating line which consists of a feed line and a return line. It is also possible to use an ultrafilter as the membrane filter. There is provided a leveling tube connected by respective pipes to the concentrate tank at top and bottom portions thereof, respectively. A buoy floats within the leveling tube and a position of this buoy is detected by means of transparency of the leveling tube itself or photosensors in order to detect a degree of concentration of the culture fluid progressing within the concentrate tank. There may be provided multi-stage circulating lines each connecting the associated concentrate tank to the associated membrane filter so that the culture fluid can be transferred during the process of concentration from the stage of the largest volume treatment to the state of the least volume treatment in order to concentrate the culture fluid more efficiently.

Abstract: A continuously variable transmission has a drive pulley having a shiftable disc, a driven pulley having a shiftable disc, a belt engaged with both pulleys, a transmission ratio control valve having a plunger slidably mounted in a valve body, a spool for controlling transmission ratio and, a spring provided between the plunger and the spool. A selector device is provided for selecting a high engine speed driving range. The selector device has an actuator responsive to the selection of the high engine speed driving range for shifting the plunger to increase the load on the spring, and a correcting lever for controlling the operation of the actuator in accordance with the transmission ratio.

Abstract: A pressure control valve has a spool slidably mounted in a valve body. The valve body has a chamber between opposed lands of the spool. An oil guide is provided in the chamber. The oil guide has a passage arranged to apply oil pressure to the lands. The passage has a small cross-sectional area so as to reduce pulsation of oil pressure.

Abstract: A continuously variable transmission has a drive pulley, an annular groove formed on a side of the drive pulley, and a pitot tube provided in the annular groove. The pitot tube has an elliptic section, and the major axis of the ellipse is arranged in a tangential direction of an annular flow of oil in the groove. An open end of the pitot tube faces to said flow of oil.

Abstract: A system for an infinitely variable belt-drive transmission for an engine comprises a primary pulley having a hydraulically shiftable disc, a secondary pulley having a hydraulically shiftable disc, a belt engaged with both pulleys, and a hydraulic circuit. A transmission ratio control valve having a spool is provided to be responsive to engine speed for controlling the oil and for shifting the disc of the primary pulley to change the transmission ratio. Pitot pressure dependent of the engine speed is applied to the spool to shift it against a spring, the force of which is determined by the depression of an accelerator pedal. The load on the spring is increased to provide a downshifting operation of the transmission, when the large transmission ratio range is selected.

Abstract: A parking lock mechanism for a vehicle having an infinitely variable transmission provided with a synchronizer for engaging a forward gear train and a reverse gear train with a main shaft of the transmission. A parking lock position in a shift pattern of a selector lever is located adjacent a reverse position so that the selector lever can be shifted to the parking lock position passing through the reverse position. This means that the selector lever can not be shifted during forward driving of the vehicle.