PURPOSE: To enhance the use life of a pump tube and to prevent counterflow of material to be conveyed, by specifying the pressing angle of a rotor for pressing the pumping tube making contact with the inner periphery of a drum, and the rate of increase in the diameter of the drum with respect to diameter of the rotor.
CONSTITUTION: When a rotor 4 is rotated inside of the pumping tube 1, rollers 3 at opposite ends of the rotor 4 presses the pumping tube 1 against a drum 2. Accordingly, ready-mixed concrete or the like charged in a hopper 6 in an intake end 1a is successively fed under pressure through the pumping tube 1. Estimating that the roller 3 initiates pressing the pumping tube at 6 o'clock position and terminates pressing at 12 o'clock position, the pressing angle therebetween is set to 180 deg. Further, the rotating diameter of the rotor 3 after 12 o'clock position, is held to be uniform. Meanwhile, the diameter of the drum 2 after 12 o'clock position is set to be larger than that of the drum at least between 6 o'clock position and 12 o'clock position by 105% to 400%.
SAKAGUCHI MASAAKI
TANAKA KATSUSHI
KYOKUTO KAIHATSU KOGYO CO