RU2779809C1 - Indirect heating boiler - Google Patents

Abstract

FIELD: thermal power engineering.

SUBSTANCE: invention relates to thermal power engineering, more specifically to devices for heating water. The indirect heating boiler contains an inner stainless steel tank with heated water inlet and outlet pipes, which is rigidly fixed in the stainless steel outer tank with the heat carrier inlet and outlet pipes. What is new is that coolant flow guides are provided on the outer surface of the inner tank, made in the form of segments of metal tapes, and these guides are placed with the ability to ensure the movement of the coolant through the labyrinth and enveloping the inner tank along the entire contour. The coolant flow guides can be placed horizontally or at an angle relative to the horizontal plane.

EFFECT: increase the heat transfer efficiency and increase the strength of the structure.

3 cl, 3 dwg

Description

The present invention relates to thermal power engineering, more specifically, to devices for heating water.

The indirect heating boiler is a water heating equipment that uses the heat of the heating system. Such a boiler provides heating of water to high temperatures and keeping it hot. An indirect type water heater can be installed both in apartments, private houses, and in hotels, various organizations, sports complexes, boiler houses, and industrial enterprises.

From the prior art, an auxiliary hot water storage tank is known, including: a hollow external tank, a buffer tank installed around the central axis of the internal volume of the external tank for temporary accumulation and supply of hot water, a water heating coil placed between the external tank and the buffer tank, having one the end of the inlet pipe, brought from the outside through the body of the external tank, and having an outlet pipe at the opposite end, communicating with the buffer tank, the first water supply channel connected to the coil for heating water through the inlet pipe, the first outlet channel of the buffer tank, the second water supply channel, into which through the inlet pipe on one side of the external tank, a heat carrier is supplied to heat the water in the coil, which enters through the first water supply channel and exits through the first outlet channel and the second outlet channel, which has an outlet through the pipe on the opposite side of the external tank for outlet of the coolant supplied through the second water supply channel (see Fig. RU 2564739 dated 10.10.2015).

Such a device allows you to provide hot water in sufficient volume while equalizing fluctuations in the temperature of hot water. At the same time, the disadvantages include the insufficient efficiency of heat transfer between the hot coolant and the heated water.

One of the closest technical solutions can be considered an indirect heating boiler containing an inner tank made of stainless steel with inlet and outlet pipes of heated water, which is rigidly fixed in the outer tank with inlet and outlet pipes of the heating fluid, thermal insulation, while the outer tank is made of stainless steel and is connected to the inner tank by welded walls (see RU 181948 dated 07/30/2018).

Such a boiler has sufficient rigidity of the internal tank and is reliable in operation, but, as in the previous case, it has a low heat transfer efficiency due to the fact that the coolant does not have time to transfer all the accumulated energy to heat water.

The technical problem to be solved by the present invention is to create a simple and manufacturable indirect heating boiler in production and operation, which has sufficient reliability, durability in operation and high efficiency of hot water supply.

The technical result achieved in this case is to increase the efficiency of heat transfer and to increase the strength of the structure.

The technical result is achieved due to the fact that the proposed indirect heating boiler contains an inner stainless steel tank with inlet and outlet pipes of heated water, which is rigidly fixed in an outer stainless steel tank with inlet and outlet pipes of the coolant. New, according to the proposed invention, is that on the outer surface of the inner tank there are guides for the flow of the coolant, made in the form of pieces of metal tapes, and these guides are placed with the ability to ensure the movement of the coolant through the labyrinth and around the inner tank along the entire contour.

It may be advisable if the coolant flow guides are placed horizontally or at an angle relative to the horizontal plane.

Equipping the outer surface of the inner tank with coolant flow guides, creating a labyrinth for the movement of the coolant, makes it possible to increase the heat transfer efficiency by increasing the heat transfer surface, as well as by mixing the coolant (creating turbulence) and rounding the entire contour of the inner tank. At the same time, the coolant flow guides are, at the same time, stiffeners, which makes it possible to increase the strength of the structure, increasing the rigidity of the inner tank.

Further, the invention will be disclosed in more detail, with reference to the drawings, which depict:

- in Fig. 1 - schematic diagram of an indirect heating boiler, general view;

- in Fig. 2 - the direction of the flow of the coolant with horizontally located guide stiffeners;

- in Fig. 3 - direction of flow of the coolant with obliquely arranged guide stiffeners;

The boiler is made according to the "tank-in-tank" technology and uses the principle of heat exchange between the heat carrier from the heating system (CO) and the hot water supply system (DHW).

The boiler consists of two tanks placed one inside the other. The inner tank 1 is made of stainless steel sheet, for example, food steel AISI 304. The inner tank 1 is a container for heated water (sanitary water) of the DHW system.

The outer tank consists of an inner surface 2 made of stainless steel sheet, for example AISI 201 steel, and an outer surface (skin) 3 made of stainless steel sheet, for example AISI 430 steel. Between the outer surface of the inner tank 1 and the inner the surface 2 of the outer tank forms a space - a skirt of the heating system, designed to circulate the heat carrier of the heating system.

The inner and outer tanks are continuously welded and are preferably cylindrical.

The inner tank is attached to the outer tank. Fastening can be made, for example, welded, by connecting the walls around the perimeter of the inner tank at the junction of the shell and the bottom. Such fastening will ensure the reliability of the connection of the tanks and increase the efficiency of heat exchange between sanitary water and the heat carrier.

The execution of the inner and outer tanks completely from stainless steel of the same class eliminates the formation of an anode-cathode pair and does not allow electrochemical corrosion inside the boiler structure, which increases its reliability and service life.

The indirect heating boiler contains an inlet pipe 4 of cold sanitary water, a tube 5 for a temperature sensor, an outlet pipe 6 of hot sanitary water, a pipe 7 for recirculating hot sanitary water, an inlet pipe 8 of the heating fluid (heat carrier) of the heating system, an outlet pipe 9 of the heating fluid (heat carrier) heating systems.

To reduce heat loss, the boiler can be insulated, for example, with polyurethane foam 10. A decorative boiler cover can also be provided, which is made, for example, of fabric (carbon) with a foam backing.

To exclude air locks, the boiler can be equipped with a Mayevsky crane (not shown).

To improve the performance of the boiler due to more intensive heat exchange between CO and DHW and increase the strength of the boiler by strengthening the structure of the inner tank, water flow guides 11 are provided inside the water skirt, which create an intense flow that increases the heating power of the inner tank, which gives a higher performance of hot water. water. Guides 11 also act as stiffeners, which increase the strength of the structure.

Guides 11 (stiffening ribs) are made in the form of pieces of metal bent tapes, attached by welding from the outer side of the inner tank wall. The length of each guide 11 is selected to be less than the length of the circumference generatrix of the outer surface of the inner tank 1, which allows you to create a labyrinth (additional resistance) for the passage of the coolant and make the coolant fully go around the inner tank 1 along the entire circuit. In addition, the guides 11 increase the heat exchange surface area, and also increase the turbulence of the water flow by increasing the flow rate and creating a complex flow pattern of the coolant, which increases the intensity of the heat transfer process.

It should be noted that the guides 11 can be placed both horizontally (figure 2) and at an angle (figure 3), which, depending on the operating conditions, increases the turbulence of the coolant flow, intensifying heat transfer and increasing the efficiency of the boiler.

The boiler is preferably designed for floor mounting. The lower support of the boiler can be made according to the principle of an annular support, which makes it possible to evenly distribute its weight on the floor surface and ensure stability.

Boiler indirect heating works as follows.

The inner tank is filled with cold sanitary water to avoid the creation of atmospheric pressure in it and the possible squeezing of the inner tank by pressure from the heating system.

The skirt of the heating system is filled with the heat carrier of the heating system, which washes the internal tank with sanitary water and heats it.

The cold water inlet and hot water recirculation connections ensure mixing of the incoming cold water and the return water recirculating to the internal tank.

The technology of stiffening ribs on the inner tank in the skirt of the heating system makes it possible to provide an operating pressure in the DHW circuit up to 8 bar, and in the CO circuit up to 4 bar, at a working temperature of the coolant up to 80°C.

Thus, a simple and manufacturable indirect heating boiler is proposed, which provides efficient heat exchange due to a more developed heat transfer surface and the possibility of mixing the heat carrier during heat transfer.

Claims (3)

1. An indirect heating boiler containing an inner stainless steel tank with inlet and outlet pipes of heated water, which is rigidly fixed in an outer stainless steel tank with inlet and outlet pipes of the coolant, characterized in that on the outer surface of the inner tank there are guides for the flow of the coolant, made in the form of segments of metal tapes, and the said guides are placed with the possibility of ensuring the movement of the coolant through the labyrinth and wrapping around the inner tank along the entire contour. 2. Boiler according to claim 1, characterized in that the coolant flow guides are placed horizontally. 3. Boiler according to claim 1, characterized in that the coolant flow guides are placed at an angle relative to the horizontal plane.

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