Abstract: A cement packing vehicle includes a cement accommodating unit and an automatic packing machine for packing a predetermined quantity of powdery cement. A powdery cement service center supplies powdery cement to the cement packing vehicle. According to an order from packed-cement purchaser, the vehicle personnel in the cement packing vehicle pack the required quantity of cement by using the automatic packing machine in the cement packing vehicle, and directly distribute the packed cement to the packed cement purchaser.

Abstract: It is sought to provide a cement distribution system, with which a packed cement distribution system is simplified to greatly reduce the labor, time and cost required for the distribution and permit quick and smooth distribution of a predetermined quantity of high quality cement.

Abstract: A central station is connected to a plurality of remote stations through in-bound channels and out-bound channels. Data is transmitted from the respective remote stations to the central station through the in-bound channels and data is transmitted from the central station to all of the remote stations through the out-bound channels. Possibility of data transmission delay is reduced by changing the number of either or both of the in-bound channels and the out-bound channels according to a variation of amount of data transmitted/received between the remote statios and the central station.

Abstract: According to the present invention, there is provided a hydraulic control rod driving system in which radial clearance is formed between a piston portion and a cylinder, one or two or more step portions each composed of a cylindrical upper part having a large diameter and a cylindrical lower part having a small diameter arranged adjacent to the lower side of the upper part are provided on the piston portion along an axial direction thereof, circumferential grooves for partitioning off respective step portions are provided, and a ratio of the length of each step portion to the maximum outside diameter of the piston portion is set at 0.5 to 1.0.