RU2771848C1 - Multi-pass spiral heat exchanger - Google Patents

Abstract

FIELD: heat engineering.

SUBSTANCE: invention relates to heat engineering and can be used in recuperative heat exchange devices. In a multi-pass spiral heat exchanger, which includes a tape spiral winding, consisting of turns that form common walls of alternating channels for the passage of hot and cold heat carriers, respectively, remote inserts in the channels on the end sides of the spiral winding, inlet and outlet pipes, a central core body, placed between the turns of the spiral winding partitions, which together form the radial walls of separate flow zones in the spiral winding, in this case, the number of radial walls formed by baffles and flow zones between them is equal to the number of coolant passages, one of the radial walls is made of baffles located across the entire width of the spiral winding turns, and the other radial walls are made of shortened baffles, with the formation of overflows between the flow zones, and cross-flows in the radial walls are alternately adjacent to one and the other side edges of the spiral coils, the inlet and outlet nozzles for hot and cold coolants are located on one, with an even number of coolant passes, or both, with an odd number of passes, the end sides of the spiral winding in pairs within the boundaries of the flow zone, remote inserts in the channels on the end sides of the spiral winding have gaps through which the cavities of the inlet and outlet pipes for hot and cold coolants are connected to corresponding channels of the flow zones.

EFFECT: simplification of the design, and provision of multi-pass movement of heat carriers.

1 cl, 3 dwg

Description

The invention relates to recuperative heat exchange devices and can be used in the chemical, food industry, oil and gas processing, power engineering, household services and other industries that require heating or cooling of gases and liquids.

Known heat exchangers with a sheet heat transfer surface [1] in relation to currently widely used shell-and-tube heat exchangers have a lower specific material consumption and a higher unification factor.

Known plate heat exchangers [2] with a heat transfer surface of parallel heat-conducting sheets, which form slotted channels for the passage of heat carriers. With a small channel width, plate heat exchangers have a high compactness. Their disadvantage is the increased hydraulic resistance to the passage of coolants and the difficulty of manufacturing.

Known heat exchanger with a heat transfer surface of the tape, bent and wound into a flat spiral around the fold axis so that the cavities between adjacent turns of the tape surface form alternating channels for hot and cold coolants [3]. The heat exchanger has an increased heat transfer rate and high compactness. The disadvantage of the known heat exchanger is the complexity of manufacturing and the need to use special technological equipment. This is due to the fact that for the formation of spiral channels it is necessary to roll two tapes simultaneously, while ensuring a uniform gap between the turns, which is quite difficult to implement.

Known spiral heat exchanger, including tape spiral winding, consisting of coils, forming common walls of alternating channels for the passage of hot and cold coolants, respectively, remote inserts in the channels on the end sides of the spiral winding, inlet and outlet pipes for coolants, the central body-core [ 4] - prototype. Known spiral heat exchanger has a relatively low specific material consumption and low contamination of the walls of the channels; characterized by high compactness. Its disadvantage, as for other well-known spiral heat exchangers, is the complexity of manufacturing, associated with the need to roll two tapes at the same time. Another disadvantage of spiral heat exchangers and the prototype, including the movement of each of the coolants in one channel and only one stroke, which limits the use of spiral heat exchangers, not allowing them to be used, for example, for coolants characterized by high Prandtl numbers, when the length of the channel (stroke), calculated in calibers, should be hundreds of units.

The technical problem to be solved by the present invention is to simplify the design and to ensure the multi-pass movement of heat carriers in a spiral heat exchanger.

This problem is solved by the fact that a multi-pass spiral heat exchanger, including a tape spiral winding, consisting of coils forming common walls of alternating channels for the passage of hot and cold heat carriers, respectively, remote inserts in the channels on the end sides of the spiral winding, inlet and outlet pipes, a central the core body has partitions placed between the turns of the spiral winding, which together form the radial walls of separate flow zones in the spiral winding, while the number of radial walls formed by the partitions and the flow zones between them is equal to the number of coolant passages, one of the radial walls is made of partitions located along the entire width of the turns of the spiral winding, and the other radial walls are made of shortened partitions, with the formation of overflows between the flow zones, and the overflows in the radial walls alternately adjoin one and the other side edges of the spiral turns winding, the inlet and outlet pipes for hot and cold coolants are located on one, with an even number of passes of the heat carriers, or both, with an odd number of passes, the end sides of the spiral winding in pairs within the boundaries of the flow zone, remote inserts in the channels on the end sides of the spiral winding have gaps through which the cavities of the inlet and outlet pipes for hot and cold coolants are connected to the corresponding channels of the flow zones.

In contrast to the known device [4], the placement of partitions between the turns of the spiral winding, which together form the radial walls of separate flow zones in the spiral winding, and the number of radial walls formed by the partitions and the flow zones between them is equal to the number of coolant passages, one of the radial walls is made of baffles located across the entire width of the coils of the spiral winding, and other radial walls are made of shortened partitions, with the formation of overflows between the flow zones, the overflows in the radial walls alternately adjoin one and the other side edges of the spiral windings, inlet and outlet pipes for hot and cold coolants are placed on one, with an even number of passes of coolants, or both, with an odd number of passes, end sides of the spiral winding in pairs within the boundaries of the flow zone, remote inserts in the channels on the end sides of the spiral winding have gaps through which the cavities enter Inlet and outlet pipes for hot and cold heat carriers are connected to the corresponding channels of the flow zones, which makes it possible to simplify the design, improve the manufacturability of its manufacture and ensure the multi-pass movement of heat carriers for any even and odd number of passes.

In the proposed multi-pass spiral heat exchanger, the spiral winding is created by folding one sheet, which is technologically easily feasible. In a spiral winding, each of the heat carriers moves in parallel flows through the channels, by varying the number of which and their cross-sectional area, it is possible to change the flow rates of the heat carriers and the thermal power of the multi-pass spiral heat exchanger over a wide range.

The presence of multi-pass heat carriers expands the possibilities of layout solutions of the heat exchanger, allows you to increase the speed of the flow and, accordingly, the intensity of their heat transfer, which as a result ensures a high compactness of the device. In this case, it is possible to carry out the most preferable countercurrent movement of hot and cold coolants throughout their entire path in the channels of the spiral winding.

Thus, the totality of the distinguishing features of the invention allows us to solve the problem.

Comparative analysis of the proposed technical solution with the prototype shows that the proposed device meets the criterion of invention "novelty".

Known similar devices are structurally complex and difficult to manufacture, they are single-pass for coolants.

All this allows us to conclude that the proposed technical solution meets the criterion of the invention "significant differences".

The figures show a special case of a 3-way spiral heat exchanger. In FIG. 1 shows a bottom view of a multi-pass spiral heat exchanger; in fig. 2 - section A - A in Fig. one; in fig. 3 - section B - B in Fig. 2.

The multi-pass spiral heat exchanger includes a tape spiral winding of coils 1, made by folding one tape, with one end fixed on the central body core 2. Channels 3 and 4 are formed between the coils 1 of the spiral winding for the passage of hot and cold heat carriers, respectively. On the end sides of the spiral winding in channels 3 and 4 there are spacer inserts 5 having gaps 6 and 7, through which channels 3 and 4 are connected to the cavities of the inlet 8, 9 and outlet 10, 11 nozzles for hot and cold coolants. In the direction of the axis of the spiral winding in the channels 3 and 4 between the turns there are solid baffles 12, occupying the entire width of the turns 1, and shortened baffles 13 and 14, occupying parts of the width of the turns 1. The solid baffles 12 form a radial wall 15 impervious to heat carriers, and the shortened baffles 13 and 14 form radial walls 16 and 17. Radial walls 15, 16 and 17 separate the spiral winding into flow zones (heat carrier passages) with a sectoral cross-sectional shape. The flow zones (heat carrier passages) in the considered particular case of a 3-way spiral heat exchanger are interconnected by flows 18 and 19, made in radial walls 16 and 17 and alternately adjacent to one and the other side edges of the coils 1 of the spiral winding. Inlet 8, 9 and outlet 10, 11 nozzles for hot and cold coolants are placed on the end sides of the spiral winding in pairs within the boundaries of adjacent flow zones, separated from each other by a radial wall 15 impervious to coolants.

The operation of a multi-pass spiral heat exchanger according to the counterflow scheme, for example, is carried out as follows. The hot coolant enters through the inlet pipe 8 and breaks 6 in the spacer inserts 5 into the channels 3 of the flow zone, which is limited by a radial wall 15 impervious to coolants and a radial wall 16 formed by shortened partitions 13. Moving in the channels 3 of the flow zone in the direction parallel to the axis of the spiral winding , the hot coolant reaches the overflows 18 in the radial wall 16, through which it enters the adjacent flow zone bounded by the radial walls 16 and 17. the next flow zone, limited by the radial wall 17 and the impermeable radial wall 15, where, after a new turn, it again reverses the direction of movement. Further, through the breaks 6 of the remote inserts 5 enters the cavity of the outlet pipe 11, from where it is removed from the multi-pass spiral heat exchanger.

The cold coolant enters the cavity of the inlet pipe 9, through gaps 7 in the spacer inserts 5 it is distributed along the channels 4 of the flow zone bounded by radial walls 15 and 17, where it moves towards the opposite end of the spiral winding. Further, the cold coolant through the overflows 19 enters the flow zone bounded by the radial walls 16 and 17, after turning by 180 ° moves in the channels 4 in the opposite direction and, having reached the overflows 18, through them enters the next flow zone, limited by the radial wall 16 and impermeable by a radial wall 15. Turning 180° and passing through the last flow zone with its final third pass, the cold coolant enters the cavity of the branch pipe 10 through the gaps 7 of the remote rates 5 in the channels 4, from where it is discharged from the multi-pass spiral heat exchanger.

The movement of the hot coolant in the channels 3 and the cold coolant in the channels 4 of the spiral winding is accompanied by their thermal interaction through the walls of the coils 1 separating the channels. The result of the heat transfer process is the cooling of hot and heating of cold coolants.

The tape for making turns 1 of the spiral winding can be metal or plastic and have a thickness from fractions of a millimeter to several millimeters. The width of channels 3 and 4 for the passage of heat carriers can be assigned within a wide range and range from several millimeters to tens of millimeters.

Example. A three-way spiral air-to-air heat exchanger is used in a supply and exhaust ventilation system with heat carrier flow rates of 45,000 m ³ /h. Its thermal power is 320 kW. The material of the tape from which the spiral winding is made is polycarbonate, its thickness is 0.25 mm. The width of the channels between the turns of the spiral winding is 5 mm, and the average diameter of the central core body is 0.1 m. With these indicators, the transverse overall dimension (diameter) of the spiral winding is 1.6 m, and its width is 0.8 m. the heat transfer surface of the heat exchanger is 345 m ² . In conditions of countercurrent movement of heat carriers, supply air in the heat exchanger is heated from -5°C to +20°C at an average temperature difference between heat carriers of 7°C. The pressure loss of each of the air streams on the way from the inlet to the outlet is 3200 Pa.

The proposed device has the following advantages:

- constructive simplicity;

- manufacturability;

- compactness;

- the ability to provide any, even or odd, number of coolant passes;

- the ability to provide the most preferable countercurrent movement of heat carriers along the entire path of their movement in the heat exchanger at any number of strokes.

Information sources

1. Ponikarov I.I., Gainullin M.G. Machinery and apparatus for chemical production and oil and gas processing. Ed. 2nd, revised. and additional - M .: Alfa-M, 2006, p. 153-166, fig. 2.35-2.54.

2. Machines and devices for chemical production / A.S. Timonin, B.G. Boldin, V.Ya. Borshchev, Yu.I. Gusev and others // Under the general. ed. A.S. Timonina - Kaluga: N.F. Bochkareva, 2008. p. 486, fig. 6.1.3.1.

3. Patent RU No. 2141089 C1, IPC F28D 7/04. Published 1999.11.10.

4. Ponikarov I.I., Gainullin M.G. Machinery and apparatus for chemical production and oil and gas processing. Ed. 2nd, revised. and additional - M .: Alfa-M, 2006, p. 165, fig. 2.52.

Claims (1)

A multi-pass spiral heat exchanger, including a tape spiral winding, consisting of turns forming common walls of alternating channels for the passage of hot and cold heat carriers, respectively, remote inserts in the channels on the end sides of the spiral winding, inlet and outlet pipes, a central core body, characterized in that baffles are placed between the turns of the spiral winding, which together form the radial walls of separate flow zones in the spiral winding, while the number of radial walls formed by the partitions and the flow zones between them is equal to the number of coolant passages, one of the radial walls is made of partitions located across the entire width turns of the spiral winding, and the other radial walls are made of shortened partitions, with the formation of overflows between the flow zones, and the overflows in the radial walls alternately adjoin one and the other side edges of the spiral windings, the inlet and outlet inlets for hot and cold coolants are located on one, with an even number of coolant passes, or both, with an odd number of passes, end sides of the spiral winding in pairs within the boundaries of the flow zone, remote inserts in the channels on the end sides of the spiral winding have gaps through which cavities inlet and outlet nozzles for hot and cold heat carriers are connected to the corresponding channels of the flow zones.

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