PURPOSE: To obtain a molded article having uniform quality, by measuring successively the density of urethane material, by mixing in the urethane material a gas in a quantity corresponding to a value obtained from measurement, and by maintaining thereby the density of the material at an arbitrary constant value.
CONSTITUTION: Urethane material supplied to a material tank 1 is agitated by an agitator 1a, and most of it is supplied to a molding die via an injection pipe 4. Meanwhile, a part of it is sent to a gas mixing tank 6 through a subtank 5 and mixed with air in a cylinder 8 via a valve 10, and then is circulated in the material tank 1. A differential pressure oscillator 11 is attached to the abovementioned device to measure a pressure difference P between the upper- stream and down-stream sides of the subtank 5. The measured difference is converted into the density of the material urethane, and then this is sent to a metering-recording regulator 14 (a mark 14a denotes a display board) and compared with the set density of material. Based on a difference signal thus obtained, a quantity of air to be mixed in is controlled through the intermediary of the valve 10, and thereby the density of the urethane material 2 in the tank 1 is maintained at a prescribed value.
SUGIMOTO YOSHINORI
SASAKI YOSHIYUKI
KOYAMA TSURUICHI
TOHO KIKAI KOGYO KK
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