RU2365840C1 - Grain dryer of pseudoliquid layer - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention pertains to drying machinery and may be used for drying of seeds of various agricultural crops. Grain dryer of pseudoliquid layer contains a loading device, drying chamber, filter, heater, worked air purification system, fan. Dryer is equipped with cooling chamber with lattice bottom, lateral side whereof is cone-shaped with incline angle a toward the central part of the lattice bottom, equal to the maximal angle of the natural slope of wet grains, and drying chamber is fixed coaxially inside cooling chamber with a gap in the bottom part, whereat in the central part of the lattice bottom of the cooling chamber along the diametre of the drying chamber there is a header widening down wise with arranged inside heating elements.

EFFECT: invention should prevent overheating of grains and improved seeding qualities.

1 dwg

Description

The invention relates to drying equipment and can be used for drying seeds of various crops.

A known fluidized bed dryer containing a loading device with a screw feeder, a heater, a fan, an exhaust air purification system and a drying chamber, the bottom of which is a perforated surface covered with a stainless steel wire mesh with openings (patent RU 2305240, F26B 17/10).

The disadvantage of this installation is that when drying in a boiling state, due to intense heat transfer, the grain heats up to the maximum permissible temperature already in 50 ... 200 s depending on the temperature of the drying agent. A decrease in grain moisture by 3 ... 4% is accompanied by an increase in its temperature to 55 ... 60 ° C. Further drying leads to overheating of the grain, which affects its sowing quality.

The objective of the invention is to remedy this drawback.

The problem is solved due to the fact that the known dryer containing a loading device, a drying chamber, a filter, a heater, an exhaust air purification system, a fan, according to the invention is equipped with a cooling chamber with a grating bottom, the side of which is conical with an angle of inclination α to the central part of the grating bottom equal to the maximum angle of repose of wet grain, and the drying chamber is fixed coaxially inside the cooling chamber with a gap in the lower part, while in the central part On the grating bottom of the cooling chamber, a nozzle is fixed along the diameter of the drying chamber, expanding downward with the heating elements located inside.

The technical essence of the proposed dryer is presented in the drawing, which shows the technological scheme of the grain dryer fluidized bed.

The fluidized-bed grain dryer (see drawing) contains a cooling chamber 5 with a trellised bottom 7, the lateral part of which is conical with an inclination angle α to the central part of the trellised bottom 7, equal to the maximum angle of repose of wet grain. The drying chamber 6 is fixed coaxially inside the cooling chamber 5 with a gap 10 in the lower part. In the central part of the grating bottom 7, a nozzle 8 is fixed along the diameter of the drying chamber 6, expanding downward, designed to increase the air flow rate in the drying chamber 6. Heating elements 12 are located inside the nozzle 8. The air is supplied to the working chambers by a fan 13 through a discharge pipe 9. Wet the grain enters the dryer through the loading pipe 14 with the shutter 2 open, the dried grain is discharged through the pneumatic pipe 11 with the shutter open 15. The spent drying agent is removed from the kiln ry 6 through the pipe 4 at open throttle 3 through the cyclone 1.

The technological process of drying the grain layer in a recirculating grain dryer is based on fluidization and is carried out as follows.

Wet grain is poured through the nozzle 14 into the drying chamber 6 and the cooling chamber 5 to the level of H ₀ . The air flow created by the fan 13 after the exit from the pipe 9 is divided into two parts. Most of the air flow enters the nozzle 8, passes through the heating elements 12, heats up to the required temperature and, penetrating the central part of the grating bottom 7, enters the drying chamber 6. The rest of the air flow, passing through the lateral conical part of the grating bottom 7, enters cooling chamber 5. The nozzle 8, expanding downward, increases the air flow rate to a critical one, at which a dense layer of grain in the drying chamber 6 passes into a loosened, fluidized state and reaches Height of H greater than the height of the drying chamber 6.

Part of the dried grain, heated to the limit temperature, inevitably enters the cooling chamber 5, where it is cooled by blowing with cold air and contact heat exchange with the cooled grain. At the same time, approximately the same amount of chilled grain enters through the annular gap 10 into the drying chamber 6 and mixes with the circulation flows of the heated grain. The process is repeated. Spent drying agent, light impurities and purge air from the cooling chamber enter through the pipe 4 into cyclone 1, where air is separated from impurities. Purified air enters the atmosphere. Cold air blowing of the cooling chamber 5 increases the porosity of the layer above the grating bottom 7 and eliminates the formation of stagnant zones in the annular gap 10. For the grain to reach conditioned humidity, the grain must undergo the process described above many times. After drying, shutters 2 and 3 are closed, shutter 15 opens, heating elements 12 are turned off, the grain is cooled and transported by air flow through a pneumatic pipe 11 to the storage.

The proposed fluidized bed dryer allows you to:

- to carry out grain recycling inside the dryer with alternating heating-cooling cycles and makes it possible to supply a drying agent with a high temperature to the drying chamber without the risk of overheating and deterioration of grain quality, which, in turn, will increase the drying speed;

- at the same time cleanse grain heap of light impurities;

- to separate the cold air flow from the heated one and reach the critical speed of the latter, at which the dense layer of grain in the drying chamber passes into a loosened, fluidized state and reaches a height greater than the height of the drying chamber.

- eliminate the formation of stagnant zones in the annular gap;

- reduce the size, metal structure, as well as energy consumption by reducing loading and unloading operations, the number of elevators, fans and electric motors compared with existing drying units of this type.

The proposed grain dryer does not require the selection of grain batches by moisture and weediness. Thanks to contact moisture exchange in the cooling chamber and multiple, high-speed circulation of grain, its moisture is evened out and partially cleaned.

Claims (1)

A fluid bed dryer containing a loading device, a drying chamber, a filter, a heater, an exhaust air purification system, a fan, characterized in that it is equipped with a cooling chamber with a grating bottom, the side of which is conical with an inclination angle α to the central part of the grating bottom the maximum angle of repose of the wet grain, and the drying chamber is fixed coaxially inside the cooling chamber with a gap in the lower part, while in the central part of the grating bottom of the cool A nozzle is fixed along the diameter of the drying chamber, expanding downwards with heating elements located inside.

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