Plate heat exchanger: operating principle. Plate heat exchangers: device

Heat exchangers are simple in design devices, often included in schemes of various kinds of industrial equipment. Sometimes they are used in domestic cooling and air conditioning systems. As already can be judged by the name, these devices are designed to take heat from one medium and transfer it to another.

Main types of heat exchangers

In specialized equipment, various types of similar devices can be used: twisted, graphite, shell-and-tube, spiral, etc. However, the most economical, effective and popular type is a plate heat exchanger. The principle of its operation is based on the simple transfer of heat through the metal. In this case, the dimensions of this type of exchanger are small, and the cost is low. Such devices can be used in equipment of various purposes.

Design Features

The plate heat exchanger, the device and the principle of operation (the schemes presented in the article confirm this) are in fact very simple, consists of the following basic elements:

• Front fixed plate with nozzles. Through the latter, both working media fall into the heat exchanger.
• The upper and lower guide bars. These elements are necessary for stiffening the whole structure. The same function is performed by the rear support of the device.
• Rear movable plate.
• The plates themselves.
• Sealing gaskets serving simultaneously as delimiters between plates.

Sometimes nozzles in such heat exchangers are installed not only on the front, but also on the rear panel. In this case, everything depends on the purpose of the device and how it is included in the system. When assembling heat exchangers, various consumables are also used: fixing bolts, rubber bushings, etc.

Modern plate heat exchanger: the principle of operation

The device of this type operates in a cross-sectional scheme. The sections are alternately filled with a heated and cooled medium. Heat exchange between them occurs through the plates. Filling of sections during operation of the device is provided by gasket-seals of different shapes. The latter can either let the medium pass or delay it. As you can see, this is a very simple principle of work. Plate heat exchangers are arranged so that the media in them move towards each other. In this case, the heating is supplied from above and leaves the lower branch pipe, and the cooled one, respectively, on the contrary.

Thus all such devices function. The principle of operation of the plate heat exchanger for DHW is exactly the same as for the models intended for conditioning, cooling lubricants and so on. The only difference is in the types of medium passing through the hull. In the model for hot water, it is, respectively, water, in other devices of this type, exchange can occur between solutions, oils, gases, etc.

Specifications

When choosing plate heat exchangers, usually pay attention to such indicators as:

• power;
• consumption;
• Material and area of plates;
• Seal material;
• working temperature;
• Permissible particle size in media;
• Maximum working pressure.

Device Plates

Thus, we have found out what kind of plate heat exchanger the principle of operation is. The device of a plate at this easy-to-use equipment elementary. In each there are 2 holes under the medium. In addition, the plates may have a relief that facilitates the passage of liquids or gases. Their thickness depends on the purpose, the dimensions of the device and the pressure in it.

Since these elements of the exchanger design are constantly in an aggressive environment, they must be made from the material that is as stable as possible to it. Most often, these plates are made of stainless steel. In this case, the brand 1.4404 / AISI 316L is usually used. This steel contains molybdenum, and therefore is distinguished by increased resistance to corrosion, damage and exposure to chlorides.

In the event that not too aggressive media pass through the heat exchanger, ordinary stainless steel grades can be used to make the plates. Very often these elements are also made of titanium or titanium-palladium. Used in their production and other materials.

Heat exchanger seals

The durability and reliability of the heat exchanger depends on the quality of these elements. Seals prevent mixing of media and guide them along a certain path. At the moment, only two types of such elements are used in heat exchangers: clip-on and glue. For the production of gaskets, rubber-based materials are usually used. It can be, for example, EPDM, PVR, Viton, etc.

Adhesive seals are fixed in special grooves on the epoxy. Clip variants are installed by means of special fixing elements.

Power and consumption

Use a plate heat exchanger, the principle of operation and design is convenient, can be in a wide variety of sectors of the economy. And consequently, the power of such devices varies within quite a wide range. To date, heat exchangers from several hundred kilowatts to tens of megawatts are used in various types of heating and cooling systems. This indicator depends mainly on the number of plates used in the device and their dimensions.

Modern heat exchangers of this type can operate in the operating temperature range (-30 to 200 ^о С). Better, of course, if the cooled and heated media are thus sufficiently clean. However, the plate heat exchangers are not particularly sensitive to this factor. In most models, the maximum allowable particle size in the medium is 4 mm.

Temperature and pressure

At us in the country heat exchangers are made usually under GOST 55118-83. Such devices in most cases are able to withstand pressures up to 1.6 MPa. The temperature of working media in domestic models can fluctuate within -30 ... +180 degrees.

Scope of application

The plate heat exchanger, the principle of operation of which allows it to be incorporated into systems of very different designs, can be used:

1. On mechanical production. With the use of such devices, lubricating fluids, hydraulic and transmission oils, etc., are cooled.
2. In piston and turbine engines.
3. In power stations.
4. In the compressors.
5. In the shipping. On ships, heat exchangers are mainly used for central cooling.
6. In the light industry.
7. In machine building and metalworking.
8. In heating and air conditioning.

Modern plate heat exchangers, the device and the principle of operation of which were discussed in detail in this article, can thus be considered reliable, efficient and convenient to use. To all other, and stand such models in comparison with other varieties inexpensively. All this makes their use in various kinds of cooling and heating systems more than reasonable.