Heat exchangers are devices that are simple in design and are often included in various industrial equipment designs. Sometimes they are used in domestic cooling and air conditioning systems. As can already be judged by the name, these devices are designed to collect heat from one medium and transfer it to another.
The main types of heat exchangers
In specialized equipment, different types of similar devices can be used: twisted, graphite, shell-and-tube, spiral, etc. However, the plate heat exchanger is the most economical, efficient and popular type. Its principle of operation is based on the simple transfer of heat through metal. At the same time, the dimensions of this type of exchanger are small, and the cost is low. Such devices can be used in equipment for various purposes.
Design features
The plate heat exchanger, the device and the principle of operation (the schemes presented in the article confirm this) which are actually very simple, consists of the following main elements:
- Front fixed plate with nozzles. Through the latter, both process media enter the heat exchanger.
- Upper and lower guide rods. These elements are necessary to give rigidity to the entire 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 the plates.
Sometimes the nozzles in such heat exchangers are installed not only on the front, but also on the rear panel. In this case, it all depends on the purpose of the device and the way it is included in the system. When assembling heat exchangers, various consumables are also used: mounting bolts, rubber bushings, etc.
Modern plate heat exchanger: principle of operation
A device of this type operates in a cross pattern. The sections are alternately filled with a heated and cooled medium. Heat exchange between them occurs through the plates. Filling sections during the operation of the device provide gaskets-seals of various shapes. The latter can either skip the medium or delay it. As you can see, this is a very simple principle. Plate heat exchangers are arranged so that the media in them move towards each other. In this case, the heating is fed from above and goes into the lower pipe, and the cooled, respectively, vice versa.
Thus, all such devices function. The principle of operation of a plate heat exchanger for domestic hot water is exactly the same as for models designed for conditioning, cooling lubricants and so on. The only difference is the types of media passing through the enclosure. In the model for hot water supply, this is, respectively, water, in other devices of this type, exchange can occur between solutions, oils, gases, etc.
Specifications
When choosing plate heat exchangers, they usually pay attention to such indicators as:
- power;
- consumption;
- material and plate area;
- seal material;
- working temperature;
- permissible size of solid particles in media;
- maximum working pressure.
Device plates
Thus, we have found out what a plate heat exchanger has a working principle. The plate device of this easy-to-use equipment is elementary. Each has 2 openings for the medium. In addition, the plates may have a relief that facilitates the direction of passage of liquids or gases. Their thickness depends on the purpose, dimensions of the device and pressure in it.
Since these structural elements of the exchanger are constantly located in an aggressive environment, they should be made of the most resistant material to it. Most often, such plates are made of stainless steel. The brand 1.4404 / AISI 316L is usually used. Such steel contains molybdenum, and therefore is characterized by increased resistance to corrosion, damage and the effects of chlorides.
In the event that not too aggressive media pass through the heat exchanger, ordinary stainless steel grades can also be used for the manufacture of plates. Very often, these elements are also made of titanium or titanium palladium. Other materials are also used in their production.
Heat exchanger gaskets
The durability and reliability of the heat exchanger depends on the quality of these elements. Sealers prevent mixing of media and guide them along a specific path. Currently, only two varieties of such elements are used in heat exchangers: clip-on and adhesive. For the manufacture of gaskets, rubber-based materials are commonly used. It can be, for example, EPDM, TAC, Viton, etc.
Glue seals are mounted in special grooves on the epoxy. Clip options are installed using special locking elements.
Power and Consumption
A plate heat exchanger, the operating principle of which and the design are convenient, can be used in a variety of sectors of the national economy. And consequently, the power of such devices varies quite widely. To date, in various kinds of heating and cooling systems, heat exchangers with a capacity of several hundred kilowatts to tens of megawatts are used. This indicator mainly depends on the number of plates used in the device and their sizes.
Modern heat exchangers of this type can function in the range of operating temperatures (from -30 to 200 ° C). It is better, of course, if the cooled and heated media are clean enough. However, plate heat exchangers are not particularly sensitive to this factor. In most models, the maximum allowable particle size in a medium is 4 mm.
Temperature and pressure
In our country, heat exchangers are usually manufactured according to GOST 55118-83. Such devices in most cases are able to withstand pressure up to 1.6 MPa. The temperature of the working environment in domestic models can vary between -30 ... +180 degrees.
Scope of application
A plate heat exchanger, the principle of which allows it to be included in systems of very different designs, can be used:
- In mechanical production. With the use of such devices, lubricating fluids, hydraulic and gear oils, etc. are cooled.
- In piston and turbine engines.
- In power stations.
- In compressors.
- In shipping. On ships, heat exchangers are mainly used for central cooling.
- In light industry.
- In mechanical engineering and metalworking.
- In heating and air conditioning systems.
Modern plate heat exchangers, the device and principle of operation of which were thoroughly considered by us in the article, thus, can be considered reliable, efficient and convenient equipment to use. Everything else, and such models are inexpensive compared to other varieties. All this makes their use in various kinds of cooling and heating systems more than appropriate.