INCREASE THE EFFICIENCY OF GRAIN COOLING AFTER DRYING AND HEAT TREATMENT

One of the main requirements for grain dryers is the need for high-quality cooling of grain material after drying. Today, the most widespread are grain coolers built into grain dryers. As the practice of operation has shown, the most widespread in agriculture mine grain dryers with their cooling zones are ineffective: the temperature of the grain after cooling often exceeds the ambient air temperature by 15-30 0C, which is unacceptable. Devices with boxes have such disadvantages as uneven distribution air in the volume of grain mass and the corresponding uneven temperature field of the cooling air, limited opportunities for intensifying heat transfer during grain cooling. More promising for agricultural grain dryers are external coolers, which are installed separately from the dryer and can operate in an independent mode, which has a number of advantages: the quality of cooling improves, the productivity of existing grain dryers increases due to the use of the cooling part as a dryer. The main disadvantages of using the existing external column coolers: the need for an additional vehicle - a bucket elevator for reloading grain from the dryer to the column; vertical arrangement, it is necessary to use transporting means for grain for feeding to a considerable height. But if a pneumatic transport loader with a pulsating air flow is used as a vehicle, then the efficiency of the coolers can be increased due to the removal of a part of the heat accumulated by the grain by the transporting air flow. The paper proposes an analytical rationale for increasing the efficiency of coolers with pneumatic transport in a pulsating air flow.

Sustainable Pneumatic Transport Systems of Cereals

Technological pneumatic transport installations are designed to move materials from one place to another in various phases of the production process. For example: loadingunloading materials (cereals) using rail and marine transport, air tunnel container transport, supplying combustion installations with burning coal dust. The main parameter in pneumatic transport installations is the velocity of air. For the regime of motion with material particles in suspension, for a given flow material, the higher the velocity is the greater the pressure loss will be and thus the energy consumption for transportation will increase. In horizontal pipes at the beginning of motion flow we have a compact regime, and then due to decrease air velocity a continuous layer regime is forming. This is the apparent motion in wich the pressure losses increase with the decrease of velocity. By reducing the air velocity the thickness of the deposited material increases and the real air passage section decreases and therefore the real air velocity increases, which explains the increase in pressure loss. In vertical pipes if the air velocity decreases below the lower limit of volant transport, after a critical area of instability, a transportation fluidized bed is established, the pressure losses being much larger than the particles in suspension mode. If the velocity further decreases the particles can not be entrained in the air.

Pneumatic transport of bulk materials in construction of composite floating docks

Investigations of pneumatic transport of bulk materials used in shipbuilding have carried out. Their abrasiveness, wear of straight and curved sections of pipelines were investigated. Theoretically, the dependences of the amount of wear on various factors were defined: abrasiveness and concentration of transported particles, flow rate, pipe diameter and wear resistance of its material, structural and operational features of the transport system, etc. Formulas for determining the maximum useful life of straight and curved sections of pipelines are obtained. Theoretical results confirmed experimentally.

The Study of Law of Distribution by Pipe Length and Transparency on Transportation of Cotton with Pneumatic Transport

The article examines pneumatic transport, one of the main functions of equipment in the sequence of technological processes in ginneries, and gives the main performance of equipment in the pneumatic transport system. Also, the efficiency of the process of transporting cotton in a pneumatic transport device, time of transportation, the share of raw cotton in the internal volume of the air pipeline during transportation and processes in the pneumatic transport system were analyzed on the basis of theoretical and practical experience.

Influence of Local Resistance on Pressure and Speed Changes in Expanded Pneumatic Conveying

This article focuses on improving product quality and reducing costs to ensure the efficiency of the global production of cotton fiber, in recent years, an increase in the consumption of cotton fiber, its specific type and navigation, changing demand for quality indicators, production of products with certain quality indicators. In all processes of cotton production, as well as in the processes of transporting raw cotton using pneumatic transport, on the basis of analyzes, studies conducted to determine factors that have a negative impact on product quality and their elimination, to create resource-saving technologies that reduce production costs, theoretically the connection is substantiated by the pressure loss of the local resistance of the mixture of air and fibrous waste. Based on the analysis, theoretical equations of motion of a mixture of air and fibrous waste in the expanding part of the pipeline in currently used pneumatic transport systems have been developed. It has been theoretically proven that the angle of expansion of an expanding pipe depends on local resistances generated in the expanding part of the pipe during the movement of air and fibrous waste in the ginner.