CZ268593A3 - Cooling of lumpy or bulk material - Google Patents

Abstract

According to the invention, lumpy or granular material (1) is cooled by introducing the material (1) continuously into a tube (2), cooling it in at least part of this tube (2) by means of a low-boiling liquefied gas (3) and extracting it at the outlet orifice (6) of the tube (2). The tube (2) can be partially filled with the liquefied gas (3). The transport of the material (1) through the tube (2) can be assisted by a press ram (7). An inert gas, such as nitrogen, is suitable as a low-boiling liquefied gas (3). The process can do away completely with conveying means which, in previous processes, introduced frozen ice and heat into the cooling device. <IMAGE>

Description

Oolast techniques

The invention relates to a method and apparatus for cooling lumpy and granular material.

BACKGROUND OF THE INVENTION Lacquer-known cooling methods are used, for example, for freezing foodstuffs, embrittlement or stiffening of industrial products to be subsequently separated, crushed or grinded. Also for cold forming processes, such as putting cold steel parts on, it is necessary to pre-cool the parts.

Known cooling devices use conveying devices to convey the material to be cooled by the deep-cooled liquid, whereby the material comes into direct contact with the cooled liquid for a defined period of time. There are also cooling devices of this design with indirect cooling. , conveyor belts, chain conveyors, conveyor baskets or chambers which are filled with the material to be cooled.

In DE-41 06 599, for example, the lump material is conveyed by a chain conveyor of a low-boiling liquefied gas bath or in DE-A. 0 9 900 transports material in chambers, the walls of which are partially made up of bars.

A disadvantage of these known cooling devices is the fact that the conveying device directly or indirectly comes into contact with the deep-cooled medium. The conveying device thus becomes very cold and must therefore be made of a material resistant to cold. the service life of the materials. Furthermore, it creates problems with the storage of moving parts in deeply cooled installation areas. Furthermore, it is undesirable to freeze air humidity and dirt with subsequent icing on the moving conveyor parts and to bring in

-7.Heat its own transport equipment into the deep-cooled medium.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method and for this suitable device by which lumpy or granular material can be cooled on the conveying path without overcoming the above drawbacks.

This object is solved by the invention in that the lump or granular material is fed continuously into the pipeline, is cooled in at least one part of the pipeline by low-boiling liquefied gas and is removed at the outlet opening of the pipeline.

According to the invention, the conveying device is completely neglected. By continuously filling the pipe, pressure is exerted on the material already contained in the pipe, by which it is further conveyed until it is finally withdrawn at the outlet opening at the other end of the pipe.

In one part of the pipe, the material contained in this pipe is cooled with low-boiling liquefied gas. This cooling can be carried out by direct or indirect heat exchange as required.

If the material can come into contact with the liquefied gas without damage, it is advantageous to feed the material according to the invention continuously into a conduit containing at least partially low boiling liquefied gas through which the material is conveyed and where it is simultaneously cooled.

For example, the pipe may be bent into a U-shape and the plane formed may be perpendicular to the base surface. The material is inserted into the pipe from above and the liquefied gas is filled in the lower curved pipe section. the material is almost self-contained during further continuous loading.

Loading can take place by means of a punch, by which the material is forced into the pipe, and as a result, the cooled material exits again through the outlet opening of the pipe.

It is also possible to transport the material through the curved pipe only by the pressure exerted by the force of gravity if the material column in the perpendicular pipe on the inlet side is higher than on the outlet side.

Depending on the shape of the material, a certain pipe cross-section geometry may be chosen. For example, a circular pipe section that is larger than the grain dimensions may be selected for the granular material. it passes through the pipeline piece by piece, the gap to the wall of the pipe being so large that there is no jamming.

In particular, it is recommended to use the off-gas as a low-boiling liquefied gas.When the chilled or particulate material is crushed or milled, it is additionally advantageous to extract the evolved, vaporized inert gas during the transport and cooling of the material and Indeed, when crushing, for example, discharged batteries or old spray containers, chemically reactive substances or highly flammable substances may escape and may explode or ignite in the air. This hazard does not arise in an inert gas atmosphere.

It is further preferred that a low boiling vapor gas is used to pre-cool the lump or granular material.

Indeed, in the case of liquefied nitrogen, after receiving the heat of evaporation, nitrogen can receive more than the same amount of heat before it reaches room temperature. for example to a crushing plant.

In order to minimize evaporation of the refrigerated liquefied gas by supplying heat from the environment, at least part of the piping containing the low boiling liquefied gas should be insulated by direct cooling of the material.

According to the invention, the temperature of the lump or granular material can be controlled by the throughput of the material through the conduit. Because the pipeline is continuously filled, a larger amount of charge per unit of time of higher transport speed and thus a shorter residence time in that part of the pipeline in which the material is cooled by the deep-cooled liquid gas directly or indirectly.

In addition, the temperature of the material can be controlled by direct cooling of the low-boiling liquid gas charge in the conduit. the longer the cooling path is.

is in or

wherein the lower bent pipe section is in contact with the low boiling liquefied gas.

gas directly into the thermally insulated pipe.

However, it is advantageous if the lower bent part of the pipe is in

in a low-boiling liquefied gas bath and regulated to a constant value.

According to the invention, the material to be smoothed is filled from above into the pipe until the lower U-shaped pipe section is completely filled with material. Further continuous filling creates a pressure that transports the material through the lower-pipe section where direct or indirect heat exchange with the liquefied * ~ Low boiling point gas. Leaves the cooled pipe material out of the outlet.

Depending on the type of material, it may be necessary for it to be filled into the pipeline and conveyed by a punch. According to the invention, a punch is arranged at the inlet opening of the pipeline.

Especially in the case of lump material, it may be advantageous to adapt the cross-sectional area of the pipeline to the cross-section of the material so that the material is conveyed piece by piece through the pipeline. , but the material does not become clogged and jammed in the pipeline.

In order to prevent material jamming in the pipeline, it may be expedient to provide a pipeline with a widening DC cross-section towards the outlet opening.

Overview of the drawings

In the following, the method according to the invention is to be explained in more detail with a single drawing. The drawing schematically shows an apparatus according to the invention suitable for direct cooling of piece goods.

Exemplary embodiments of the invention

The bent pipe 2 is guided into its shape by the bottom bent part by a bath 8 with liquefied nitrogen 3. This part additionally has inflow openings 4 through which fluid exchange between the interior of the pipe and the bath 3 can take place. The bath 8 is thermally insulated. The filling level is kept constant by the corresponding control unit. The mold 7 supports the conveying of material 1 through a curved pipe 2. The cooled material 1 is removed at the outlet hole 5.

Once the pipe is filled with material 7, a different part is forced out through the outlet opening 6 with each newly added part. The residence time of the material 1 in the liquefied nitrogen bath 3 can be adjusted by the rate of throughput, and the vaporized nitrogen exits into the pipeline and causes the material to be pre-cooled and additionally cooled. to reduce the risk of jamming that could cause blockage.

When cooling the steel piston pins for the final cold setting, this embodiment of the method and apparatus according to the invention proves to be particularly suitable.

Claims (13)

Method for cooling lump or granular material, characterized in that the lump or granular material (1) is fed continuously into the conduit (2), cooled in at least one part of the conduit (2) by low-boiling liquefied gas (3) and withdrawn at the outlet opening (6) of the pipe (2). Method according to claim 1, characterized in that the lump or granular material (1) is fed continuously into a conduit (2) comprising at least partially liquefied low boiling gas (3). Method according to either of Claims 1 and 2, characterized in that the lump or granular material (1) is filled into the pipe (2) by a punch (7). Method according to one of Claims 1 to 3, characterized in that an inert gas, in particular nitrogen, is used as the low-boiling liquefied gas (3). Method according to one of Claims 1 to 4, characterized in that the low-boiling evaporation gas (3) produced during cooling is used for additional cooling of the lump and granular material (1). Method according to one of Claims 1 to 5, characterized in that the temperature of the lump or granular material (1) is controlled by the amount of material (1) passed through the pipe (2). Method according to one of Claims 2 to 6, characterized in that the temperature of the lump or granular material (1) is controlled by the amount of low-boiling liquefied gas (3) in the line (2). Device for carrying out the method according to claim 1, characterized in that the conduit (2) suitable for receiving a piece of granular material (1) is U-shaped curved, wherein the lower curved part of the conduit (2) is in contact with low - boiling liquefied gas (2). Device according to claim 3, characterized in that the lower bent part of the U-shaped pipe (2) is immersed in a low boiling liquefied gas bath (8). Device according to claim 9, characterized by. The method according to claim 1, characterized in that the lower bent U-shaped pipe part (2) has inlet openings (4) for low boiling liquefied gas (3). Device according to one of Claims 8 to 10, characterized in that a punch is arranged at the inlet opening (5) of the pipe (2). Device according to one of Claims 3 to 11, characterized in that the pipe (2) is adapted with its cross-sectional area of the cross-section of the material to be cooled. Device according to one of Claims 8 to 11, characterized in that the pipe (2) is designed with a cross-section which extends towards the outlet opening (6).