RU2622134C2 - Method of drying spherical powder - Google Patents

Abstract

FIELD: weapons and ammunition.

SUBSTANCE: method of drying spherical powder (SP) involves feeding the powder with graphite via a cyclone-precipitator into the drying chamber, powder drying by supplying the coolant to the lower part of the chamber at a temperature of 88-98°C for 60-80 minutes, then for 140-180 minutes at a temperature of 65-75°C, powder cooling and unloading into the receiving hopper. The powder drying is carried out in a rotary two-chamber apparatus in the first chamber along with the powder loading in an amount of 20-40 kg (dry weight), where the powder is dried in the first zone at a temperature of 98-65°C and with an air head of 1.5-4.9 kPa together with moisture removal. Then, by rotating the mechanism, the first chamber with the powder moves to the second zone, where, by supplying air at a temperature of 20-30°C, the powder is cooled down to a temperature of 40-60°C for 15-25 minutes, while the powder is loaded to and then dried in the second chamber.

EFFECT: increased capacity of the powder drying device by using a two-chamber drying apparatus with a separation into zones of moisture removal and powder cooling.

1 dwg, 1 tbl

Description

The invention relates to a method for drying spherical powders (TFP) obtained by water-dispersion technology for small arms.

The method of drying the TFP includes the phase of the formation of particles by the water-dispersion method, washing, sorting, phlegmatization, drying.

At the plants of the industry, the drying operation is carried out in two ways: 1 - in the 12-chamber apparatus AC-12, the principle of operation of which is based on the creation of a fluidized bed of powder in a stream of heated air supplied to the chambers by a high-pressure fan through a distributor [1]; 2 - on table dryers in a densely blown layer, while the heat of the exhaust air after drying is carried out by means of natural extraction through gas waste [2].

The disadvantages of the prototypes:

1. The proposed drying method in AS-12 in terms of equipment productivity is designed for mass production of gunpowders and is not cost-effective in the manufacture of small-tonnage pilot batches;

2. Grafitovka and drying are carried out in different devices. Grafitovka - as a separate operation is carried out in periodic polishing drums, which requires the installation of additional equipment and reduces the performance of the phase.

As a prototype [3], the authors chose a method for producing TFP, according to which spherical powder with graphite is fed through a cyclone precipitator into a drying chamber with a knock-out surface. Drying of the powder is carried out in boiling mode. The coolant is supplied to the lower part of the drying chamber for 60-80 minutes with a temperature of 88-98 ° C, then for 140-180 minutes with a temperature of 65-75 ° C and for 20-30 minutes with a temperature of 50-60 ° C. Dried gunpowder is discharged into a receiving hopper and sent by pneumatic transport through a cyclone precipitator for dry sorting.

The disadvantage of this method is the low productivity of the equipment due to the fact that the whole process of drying gunpowder is carried out in a single-chamber apparatus, which increases the duration of the operation.

The aim of the invention is to increase the productivity of the apparatus for drying gunpowder by using a two-chamber apparatus for drying with division into zones to remove moisture and cool the gunpowder.

The goal is achieved in that the method of drying spherical powder, including the supply of gunpowder with graphite through a cyclone precipitator into the drying chamber, drying the gunpowder by supplying a coolant to the lower part of the chamber with a temperature of 88-98 ° C for 60-80 minutes, then for 140-180 minutes with a temperature of 65-75 ° C, cooling and unloading of gunpowder in the receiving hopper is characterized in that the gunpowder is dried in a rotary two-chamber apparatus in the first chamber with the gunpowder loading in an amount of 20-40 kg (on dry weight), where the gunpowder dried in the first zone at a temperature of 98-65 ° and air pressure of 1.5-4.9 kPa with the removal of moisture, then by rotating the mechanism, the first chamber with the powder moves to the second zone, where by supplying air with a temperature of 20-30 ° C, the powder is cooled to a temperature of 40-60 ° C for 15-25 minutes, while at the same time 20-40 kg of wet powder is loaded into the second chamber and then the powder is dried similarly.

The technological scheme of drying spherical powder developed by the authors is presented in the drawing.

According to the developed scheme, one- or dibasic TFP with graphite and humidity 18-40 wt. % of the feed hopper SFP pos. 1 by pneumatic transport serves in the cyclone precipitator pos. 2, then the TFP from the cyclone precipitator enters the first chamber of the two-chamber drying apparatus pos. 3. At the bottom of the drying chambers, mesh poses are installed. 4, creating air resistance from 1.5 to 4.9 kPa. By pneumatic transport, from 20 to 40 kg of TFP per dry weight is loaded into the first drying chamber. The coolant is supplied to each drying chamber by a high-pressure fan; air is heated in a heater. Next, surface moisture from the TFP is removed at a coolant temperature of 88-98 ° C for 60-80 minutes, and internal moisture from powder particles at a coolant temperature of 65-75 ° C for 140-180 minutes (in the moisture removal zone). Then, due to the rotating mechanism, the first chamber is placed in the second (II) powder cooling zone, where the powder is cooled to a temperature of 50-60 ° C due to air supply with a temperature of 20-30 ° C for 15-25 minutes. The next portion of the powder in the amount of 20-40 kg is simultaneously loaded into the second chamber and moisture is removed in the first (I) zone. The dried and cooled gunpowder after drying is discharged into the product receiving bin, pos. 5 and is sent by pneumatic transport through a cyclone precipitator for further operations.

Technological modes according to the method of drying gunpowder developed by the authors within the boundary conditions (examples 1-3) and outside the boundary conditions are shown in the table.

Reducing the temperature of the coolant in the first zone of less than 65 ° C and the drying time of less than 200 minutes does not ensure complete removal of moisture from the powder particles, this leads to the removal of the duration of the drying process. An increase in the coolant temperature of more than 98 ° C and the duration of the drying process of more than 260 minutes is associated with the danger of the drying process.

The powder is cooled to a temperature of 50-60 ° C for 15-25 minutes by supplying air with a temperature of 20-30 ° C for at least 15 minutes.

An increase in the temperature of the coolant above 30 ° C increases the cooling time (Example 5), and a decrease in the temperature of the coolant below 20 ° C (especially in winter) will lead to condensation of moisture from the air on the hot granules of gunpowder.

The pressure of the supplied air is 1.5-4.9 kPa. An increase in pressure of more than 4.9 kPa leads to the transfer of gunpowder outside the chamber of the apparatus, a decrease in pressure of less than 1.5 kPa does not provide a flowing boiling mode when drying even porous finely dispersed powders.

From the data of the table it can be seen that the productivity of the drying apparatus increased by 13-14%.

The main advantage of the invention is to reduce the time of the full production cycle of TFP by increasing the productivity of the drying apparatus, which allows to obtain an economic effect.

Literature

1. Sopin V.F. Equipment for the production of spherical powders / V.F. Sopin, T.A. Eneykina, A.A. Staroverov, A.I. Khatsrinov. - Kazan, 2007 .-- 196 p.

2. Gindich V.I. Technology of pyroxylin powders. T. 2. Kazan, 1995 .-- 399 p.

3. "Method for producing spherical powder", patent RU 2516516, C06B 21/00, publ. 05/25/2014, 6 p.

Claims (1)

A method of drying spherical gunpowder, including feeding gunpowder with graphite through a precipitating cyclone to the drying chamber, drying gunpowder by supplying a coolant to the lower part of the chamber with a temperature of 88-98 ° C for 60-80 minutes, then for 140-180 minutes with a temperature 65-75 ° C, cooling and unloading of gunpowder in a receiving hopper, characterized in that the gunpowder is dried in a rotary two-chamber apparatus in the first chamber with the gunpowder loading in an amount of 20-40 kg (on dry weight), where the gunpowder is dried in the first zone at temperature 98-65 ° С and air pressure 1.5-4.9 kPa with removal m of moisture, then by rotating the mechanism, the first chamber with the powder moves to the second zone, where by supplying air with a temperature of 20-30 ° C, the powder is cooled to a temperature of 40-60 ° C for 15-25 minutes, while the second chamber is simultaneously loaded gunpowder and then gunpowder is dried.

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