Heat exchangers: types, device and principle of operation. Heat exchangers for boilers

Heat exchangers, the types of devices and the principle of operation of which will be described in the article, are special devices for transferring heat energy from the heated coolant to the cold one. The latter can be a gaseous or liquid substance.

Scope of use

The process of heat exchange is important in many industries, namely in the chemical, food, metallurgical and energy fields. The heat exchange equipment facilitates the transfer of energy between the carriers through the separation wall between them. The process can be called very complex, it is divided according to the generally accepted canons for thermal conductivity, thermal radiation and convection. In practice, these processes simultaneously take place in predetermined proportions. For heat transfer, the most important is the convective process, which is the joint action of heat conduction and convection.

Types of heat exchangers

Heat exchangers, the types of devices and the principle of operation of which must be known to the consumer before the purchase of the device, can be of different types depending on the design. If the aggregates are classified according to the heat transfer method, they can be divided into mixing and surface, as well as recuperative and regenerative. The first type involves the transfer of heat by mixing together the two working media. Such devices have a simpler design if compared with surface heat exchangers. In them, the heat energy is used more fully. However, it is possible to single out a drawback, which is expressed in the possibility of using the device only when mixing heat carriers.

Heat exchangers, the types of device and the principle of operation of which are described in the article, can be superficial, in them the working coolant exchanges energy through the walls of the separator. Such aggregates can be regenerative and recuperative.

Types of surface heat exchangers

Considering the characteristics of heat exchangers of recuperative type, you will notice that their work is based on the transfer of heat through the separation wall. Thus water rushes in one direction in each of the points of the wall. The second type of surface heat exchanger is a regenerative unit, it has a distinctive feature that is expressed in that water, touching a certain heating surface, changes the flow direction from time to time.

The design and operation principle of shell-and-tube heat exchangers

The most popular in the industry today are recuperative heat exchangers. If we divide them according to their design features, then we can single out shell-and-tube aggregates. These devices are represented by bundles of tubes that are welded to the casing. Pipes, in turn, are fixed to the tube grids, they are closed with covers on bolts or gaskets. The first heat carrier, overcoming the choke located on the body, flows through the pipe space. Another coolant runs through the pipes.

Such shell-and-tube heat exchanger has a number of moves, on the cover and its body there are partitions. To increase heat transfer, pipes are manufactured with ribbing by tape winding or knurling. The shell-and-tube heat exchanger can have a fairly simple design, while the device is called elemental and has no partitions. Such units can tolerate high pressure, but their design will be heavier and cumbersome.

Principle of operation and arrangement of a plate heat exchanger for boiler equipment

Plate-type heat exchangers, the types, arrangement and operation of which are described in this article, belong to the class of recuperative devices. These devices have a heat exchange surface, which is formed by a whole set of stamped thin steel plates with a corrugated base. These heat exchangers for boilers are composed of elements that are assembled in a single package, which forms channels among themselves, at the last pass a heat transfer medium exchanging thermal energy.

The principle of operation of such devices can not be called the simplest, in it the plates are installed in relation to each other with a rotation of 180 degrees. This allows you to compose 4 elements, of which two will refer to the collector contour of the tap, while the other will be connected to the supply of the coolant.

The two extreme elements will not participate in the process of heat energy exchange. Such heat exchangers for boilers can have a different principle of operation depending on the arrangement, which is multi-way or one-way. In the latter case, the coolant is divided into parallel flows, it passes through all channels and rushes to the port. A multi-way arrangement involves the use of a more complex circuit, since the heat exchanger in this case moves along the same number of channels. This is achieved in a slightly different way, which is expressed in the presence of additional plates. They include deaf ports. Among other things, it is somewhat more difficult to maintain this kind of plate heat exchanger.

Characteristics of oil heat exchangers

The oil heat exchanger is used to exclude an increase in the temperature of the coolant to a critical limit in high-power engines. If you allow overheating of engine oil, this can cause serious problems that can be expressed in changing the viscosity of the fuel, as well as increasing the intensity of its burning out. If the substance is overheated, the lubrication of the rubbing parts is not provided with sufficient quality, this can complicate the cooling of the engine.

Pros of oil heat exchangers

The use of such a device allows obtaining many advantages. First, this is the elimination of the likelihood that the oil temperature will be below the temperature of the coolant. This indicates that there will be less tension in the engine parts that come into contact with the oil. Secondly, the installation of the heat exchanger can be carried out in any convenient place on the engine, while you can easily refuse many connections and long pipelines.

Heat exchangers for the bath: characteristics

The heat exchanger for a bath can be classified according to the location in relation to the heater. Thus, the device can be located directly in the body of the furnace, near the chimney pipe or near the housing of the heater. Such units are designed to perform the same functions. By the method of contact with the incandescent surface of the chimney or furnace they heat the liquid in an impressive-sized container, using the convection principle. Their use allows the owners to place the water tank not in the steam room, but in the next room. You can make this device yourself, using steel sheets, as well as pipes. Only work will not work if you do not have a welding machine, and also do not know how to work with it.