Layout and General Plans for Concrete Plants

Concrete and mortar plants can be located on platforms of flat and terraced type with a stepped terrain relief.

A terraced arrangement with location of slopes on the slope is suitable for low-power mixing plants without storage aggregates in accordance with the scheme with the arrival of vehicles to the supply hoppers, when the loading bins of the plant are loaded directly by vehicles coming from the base warehouse or crushing plant or when using the terrain Allows to reduce energy costs for moving aggregates and cement from operating warehouses to a mixing plant, and t kzhe when within a radius of transporting the mixture can not find the site of the plain type.

Rational use of the terrain at the location of the warehouse on the upper elevations of the site, and the mixing plant at lower elevations allows you to reduce the costs of lifting aggregates and cement.

General plans (sites) of concrete plants can be classified:

1) by the nature of the factories adjoining the external routes of communication: to rail, road, water and mixed;

2) according to the configuration: on elongated, mainly with the direction of intrafactory cargo flow perpendicular to the major axis of the site, and on the platforms approaching in shape to the square; On stretched areas it is easier to place a large unloading front, exhaust pylons, arrows, congresses; The sites, according to the configuration approaching the square ones, became widespread in the motor transport supply with raw materials;

3) on the location of the internal railways - on the sites with dead ends, through and through the circular paths: with the through paths, the platform stretches out in length, while in the ring roads it grows in length and width;

4) depending on the profile of the site - on the horizontal and terraced: when the plant is located on terraces, it is possible to reduce energy costs for moving raw materials from the top marks to the lower ones, but the use of rail transport becomes more complicated.

Schemes of the master plan for concrete and mortar plants can be arranged:

1) with a transverse production flow directed perpendicular to the major axis of the site;

2) with a longitudinal production flow directed along the major axis of the site;

3) with the combined longitudinal and transverse direction of the production flow.

The layout of the master plan can be made according to the scheme of separate building with free-standing facilities and block scheme by combining in a common block of concrete mixing plant, cement warehouse, heating bunkers, vibro-grinding plant. The last technical solution can be implemented mainly by using elevators for vertical transport of materials, vertical or inclined high-speed screw conveyors and pneumatic transport.

The use of the block scheme makes the concrete plant more compact, increases the building factor, reduces the space required for its placement, allows to save on the building volumes of buildings and structures and reduces heat losses in the winter. The use of block building reduces capital costs and operating costs.

The disadvantage of this arrangement is the need for the use of filler equipment less reliability than belt conveyors. The development of conveyor belts with transverse partitions and a tubular type with zipper locks creates the prerequisites for a wider application of the block scheme.

The disadvantages of this arrangement are also the contiguity of external cargo flows to warehouse facilities in a limited area, which worsens the conditions for unloading and maneuvering of railway and road rolling stock.

To reduce the length of transportation of bulk materials, in some cases, direct attachment of individual structures to the mixing plant is carried out.

The arrangement of several adjacent mixing plants or several sections of a single mixing plant, as well as bunkers of the finished concrete mixture, should be such that the motor vehicles and locomotives of the finished mixture move without interference, and the tubs installed on the same vehicle are loaded immediately from two bins of the finished mixture. If the distance between the hopper outlets is unsuccessfully chosen, without taking into account the dimensions of the vehicles or the placement of the badao on the railway platforms, there may be some decrease in the plant's productivity due to shifts during unloading of the ready-made concrete mixture.

Significant impact on the size of the site occupied by the concrete plant, except for the capacity of the plant (the total capacity of the mixing machines), types of storage aggregates and cement.

In factories with high capacity, in addition to increasing the height of storage piles and the height of silos, as well as the concentration of storage facilities that reduce the specific area, there are structures that increase the specific area (booster, compressor, boiler room, etc.).

In the layout of the general plan, it should be borne in mind that the location of warehouses in the middle part of the site is less expedient than in the extreme, not only in terms of the possible intersection of cargo flows, but also because, in unfavorable wind directions, the dust settles on the mechanisms and automation of the mixing plant.

With the penetration of air and steam pipelines and cement wires into the ground, the exploitation of plants is complicated. There are downtime, as it often takes a long time to find a place for the breakthrough of highways. As a result of groundwater recharge, the steam mains can be flooded with water, which entails a loss of heat.

At a high level of subsoil waters, the use of trench belt conveyors is not advisable, since trenches can be flooded. In such cases, it is desirable to switch to transportation of aggregates from a warehouse to a mixing plant by ground transport, without the creation of any underground conveying devices.

When assembling the general layout of the plant, one should also bear in mind the accounting and weighing of materials.

Usually wagons with cement are weighed and sealed at the point of departure, but in some cases weighing requirements of arriving wagons with cement may be required. In this case, a special weight impasse should be envisaged for small cargo turnover and a special weight through-pass with large freight flows.