RU2747651C1 - Disk heat exchanger - Google Patents

Abstract

FIELD: transport; warehousing.SUBSTANCE: invention relates to a method for drying transport and / or storage containers for radioactive waste, in particular for spent fuel elements. Disclosed is a method for drying transport and / or storage containers for radioactive waste, in particular for spent fuel elements, wherein the container is first dewatered or mechanically dewatered. Then the inner space of the container is continuously evacuated or maintained under vacuum, and simultaneously helium gas is continuously supplied to the inner space of the container. The evacuation and / or supply of helium gas is carried out under the condition that the helium content in the inner space of the container is 50-95 vol.%, in particular 55-90 vol.%.EFFECT: invention makes it possible to dry containers with high efficiency and is suitable for containers with high heat output.11 cl; 1 dwg

Description

The invention relates to recuperative heat exchange devices for fluids and can be used in the chemical, petrochemical, oil refining and food industries, energy and other industries for heating and cooling mainly single-phase heat carriers.

Known recuperative heat exchanger type "pipe in pipe" with multiple helical ribs on the outer surface of the inner pipe, forming in the annular space of the screw channels [1]. The movement of coolants in the screw channels is characterized by an increased intensity of heat transfer. This design is metal-intensive and difficult to manufacture.

Known heat exchanger with a cylindrical shell, inside which is placed a heat transfer surface of helical fins, forming two helical channels for heat transfer fluids [2]. The heat exchanger has an increased heat exchange rate. Its disadvantage is the complexity of manufacture and the impossibility of providing high unit power of the transmitted heat flow.

Known spiral heat exchangers, in which there are two spiral channels formed by roll material, wound in an Archimedes spiral around the central dividing wall [3]. Spiral heat exchangers are compact, there are no stagnant zones at the heat exchange surface, the working medium moves along one long channel. The hydraulic resistance at the same fluid velocity is less than that of the widespread shell-and-tube heat exchangers. The disadvantage of spiral heat exchangers is the complexity of their manufacture, high specific metal consumption and poor maintainability.

Known plate heat exchanger containing a heat-transfer surface, made in the form of a package of thin heat-conducting sheets with holes for the passage of hot and cold heat carriers, gaskets of elastic material between thin heat-conducting sheets with the formation of alternating between even and odd slotted channels for the passage of hot and cold heat carriers, pressure plates, inlet and outlet fittings for coolants, tightening pins connecting pressure plates to each other along their periphery [4] - a prototype.

The movement of heat carriers in this plate heat exchanger is carried out in slotted channels with a small transverse dimension, which contributes to an increased intensity of heat transfer and a compactness of the device. The advantages of the plate heat exchanger include the design of the heat transfer surface made of sheet material of small thickness, which reduces its material consumption.

The disadvantage of the known plate heat exchanger is the complexity of its manufacture, the small length of one stroke of the working fluid, which in many cases leads to the need to use its multi-pass movement with many turns and, consequently, to a high hydraulic resistance of the device. It is allowed to work only at close values of the coolant pressures in order to exclude their overflows from channel to channel and mixing. The reason for possible overflows is the absence of gaskets on a part of the edge perimeter of one of the sides of the heat-conducting sheets around the holes and, as a consequence, the deflection of this part of the sheets under the influence of the pressure difference of the coolants.

The technical problem to be solved by the present invention is to simplify the structure and increase the efficiency of the device.

The problem posed is solved by the fact that a disk heat exchanger containing a heat transfer surface made in the form of a package of thin heat-conducting sheets with holes for the passage of hot and cold heat carriers, a gasket of elastic material between thin heat-conducting sheets with the formation of alternating even and odd slot channels for the passage hot and cold heat carriers, pressure plates, inlet and outlet fittings for heat carriers, tightening pins connecting the pressure plates to each other along their contours, designed so that thin heat-conducting sheets and pressure plates have the shape of discs, holes for the passage of heat-transfer agents in thin heat-conducting sheets and fittings for the passage of coolants are located in pairs in the central and peripheral parts of the disks, large gaskets of elastic material between thin heat-conducting sheets are made in the form of a continuous concentric winding with the formation of spiral slotted channels There are flow channels at the ends of the spiral slotted channels that adjoin the edges of the thin heat-conducting sheets around the holes; additional tightening pins are installed, placed in the holes of the thin heat-conducting sheets. In addition, there are gaskets made of elastic material on the planes of the flow channels, thin heat-conducting sheets have grooves for accommodating flow channels, large and small spacers made of elastic material, thin heat-conducting sheets have discrete roughness in the form of protrusions and depressions, the outer closed rings of large spacers are made reinforced ...

Unlike the known device [4], the execution of thin heat-conducting sheets and pressure plates in the form of discs, the placement of holes for the passage of heat carriers in thin heat-conducting sheets and fittings for heat carriers in pairs in the central and peripheral parts of the discs, the implementation of large spacers of elastic material between thin heat-conducting sheets in the form of continuous concentric winding with the formation of spiral slotted channels for coolants, the presence of flow channels at the ends of the spiral slotted channels that adjoin the edges of thin heat-conducting sheets around the holes, the installation of additional tie rods that are placed in the holes of thin heat-conducting sheets, lead to a simplification of the design heat exchanger, make it completely collapsible with a high degree of unification. Thin heat-conducting sheets are clamped on both sides by large and small gaskets made of elastic material and flow channels over the entire area of their interface, which ensures reliable operation of the device, without overflows of heat carriers, with significant pressure differences. The heat exchanger is single-pass, which helps to reduce the hydraulic resistance. The length of the spiral slotted channels for coolants can be set within a wide range and, if necessary, be large enough. The movement of coolants along a spiral trajectory leads to an increase in the intensity of heat transfer due to the impact on the flow of centrifugal mass forces.

The presence of gaskets made of elastic material on the planes of the grooves helps to eliminate the influence of uneven planes and inaccuracies in the manufacture of grooves when sealing with small gaskets. The grooves in thin heat-conducting sheets for placement of grooves, large and small gaskets made of elastic material allow fixing their position in specified places. Discrete roughness in the form of protrusions and depressions on thin heat-conducting sheets additionally intensifies heat transfer, which, together with the intensifying effect of the spiral movement of coolants in slotted channels, makes it possible to increase the compactness of the heat exchanger. Reinforcement of the outer closed rings of large gaskets expands the permissible operating pressure range of the heat transfer fluids in the heat exchanger. The presence of fittings makes it possible to work at increased internal pressures in the device.

The disk heat exchanger can operate both in a counter-flow and a forward-flow scheme.

Thus, the distinctive features of the invention solve the problem posed.

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

The known heat exchangers [1], [2] and [3] have a complex design, are not completely collapsible and are less efficient.

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

The invention is illustrated by drawings: FIG. 1 to FIG. eight.

FIG. 1 shows a general view of a disk heat exchanger; in fig. 2 - section a-a in Fig. one; in fig. 3 - section in the plane of an even spiral slotted channel for the coolant; fig. 4 is a section in the plane of an odd spiral slotted channel for a coolant; fig. 5 - flow pipe; fig. 6 is a left side view of FIG. five; fig. 7 - element 23 in FIG. 2; fig. 8 - element 24 in FIG. 2.

The disk heat exchanger contains a heat-transfer surface made in the form of a package of thin heat-conducting sheets 1, and pressure plates 2. Thin heat-conducting sheets 1 and one of two pressure plates 2, shaped as discs, have holes 3 and fittings 4 for the passage of hot and cold heat carriers, respectively located in pairs in the central and peripheral parts of the discs. Between the thin heat-conducting sheets are spacers 5 and 6, made of elastic material (for example, technical plates 2N-1-TMKShch-S-2S). The gaskets 5 are made in the form of a continuous concentric winding with the formation of alternating even and odd spiral slotted channels 7. At the ends of the spiral slotted channels 7 there are flow channels 8, which adjoin the edges of thin heat-conducting sheets 1 around the holes 3. The flow tubes 8 consist of two flat rings 9, interconnected by spacers 10. On the planes of the rings 9 there are gaskets 11 made of the same elastic material from which the gaskets 5 and 6 are made. The flutes 8, gaskets 5 and 6 are placed in grooves 12 of thin heat-conducting sheets 1, as shown in the callouts 23 and 24 (Fig. 7, Fig. 8). Tightening pins 13 are located along the contours of the pressure plates 2. Additional tightening pins 14 pass through holes 3 in the thin heat-conducting sheets 1 and through the inlet and outlet fittings 4.

To give rigidity, the pressure plates 2 are provided with radial 15 and annular 16 ribs. On the outer annular ribs 16, support bushings 17 are fixed for the nuts 18 of the tie rods 13. Support bushings 19 for the nuts 20 of the additional tie rods 14 are fixed on the crosses 21 located on the fittings 4. In the operating state of the disc heat exchanger, the nuts 18 and 20 are in a tightened position. The possibility of operation of a disk heat exchanger at elevated pressures of hot and cold heat carriers is ensured by the presence of fittings 22 in the outer closed rings of gaskets 5.

The disc heat exchanger operates according to the counterflow scheme as follows.

Any coolant, for example hot, enters through the inlet nozzle 4, located in the central part of the pressure plate 2, and, passing through it, fills the collector cylindrical space formed by holes 3 in thin heat-conducting sheets 1, small gaskets 6 and flow channels 8. From the collector space, the hot coolant passes between the spacers 10 of the flow channels 8 installed at the beginning of the even spiral slotted channels 7, moves in the channels 7 along a spiral path from the center of the discs to their periphery. Having given off heat in the process of heat transfer through the heat transfer surface from thin sheets 1 in the form of discs to the cold coolant, the flow of the hot coolant passes through the ducts 8 installed at the end of the even spiral slotted channels 7 and enters the collecting cylindrical collector space connected to the outlet fitting located on the periphery of the disk pressure plate 2. Thus, the hot coolant passes through the disk heat exchanger from the central collector space to the peripheral with a multitude of parallel flows in even spiral slotted channels 7.

The cold coolant enters through the inlet nozzle 4, located on the periphery of the pressure plate 2, into the collector space, which is a continuation of the inlet nozzle 4, from where, through the flow pipes 8 located in odd spiral slotted channels 7, many parallel flows move along a spiral trajectory in the channels opposite to the hot coolant flowing in adjacent even channels. In the process of heat transfer through thin heat-conducting sheets 1, the cold coolant is heated and through the flow channels 8 located around the holes in the central part of the thin heat-conducting sheets, it enters the collecting collector space connected to the outlet 4 on the pressure plate 2, and is discharged through this outlet 4.

Thus, each of the coolants, hot and cold, moves in a disk heat exchanger along its separate system, including inlet and outlet fittings, distributing and collecting collector spaces, flow channels around the collector spaces, a set of parallel even and odd spiral slotted channels.

An example of the implementation of the proposed device. With a distance between thin heat-conducting sheets of 3 mm, the disc heat exchanger has a specific heat transfer area per unit volume of the heat exchanger equal to 333 m ² / m ³ , and with a distance between thin heat-conducting sheets of 2 mm, this parameter will be 500 m ² / m ³ . For comparison, we note that this indicator of compactness for modern energy heat exchangers is 150 m ² / m ³ , that is, significantly less than for the proposed device.

The specific gravity of the proposed disk heat exchanger, the heat transfer surface of which is made of sheets, for example, polycarbonate with a thickness of 0.25 mm with a distance between the sheets of 3 mm, is 250 kg / m ³ , which is much less than the values of this indicator for general-purpose heat exchangers used in industry with heat transfer surface made of metal.

The proposed device has the following advantages:

• the design is simple and easy to manufacture;

• a high degree of unification;

• high maintainability;

• compactness and low weight;

• intensified heat exchange with moderate hydraulic resistance;

• the ability to work at high pressures of coolants;

• the ability to change the surface area of the heat transfer during operation by adding or removing thin heat-conducting sheets;

• low contamination of the heat transfer surface due to the absence of stagnant zones.

Information sources

1. USSR author's certificate No. 1062496. Cl. F28D 7/10, publ. 12/23/83, bul. 47.

2. Patent RU No. 2269080. IPC F28D 7/10, publ. January 27, 2006.

3. Baranovskiy NV Plate and spiral heat exchangers / NV Baranovskiy. Baranovsky, L.M. Kovalenko, A.R. Yastrebenetsky - M .: Mechanical Engineering, 1973. p. 265.

4. Timonin AS Machines and devices of chemical production / AS Timonin. Timonin, B.G. Baldin, V. Ya. Borshchev, Yu.I. Gusev and others - Kaluga: N.F. Bochkareva, 2008. 486, fig. 6.1.3.1.

Claims (5)

1. A disk heat exchanger containing a heat-transfer surface made in the form of a package of thin heat-conducting sheets with holes for the passage of hot and cold heat-transfer agents, gaskets of elastic material between thin heat-transfer sheets with the formation of alternating even and odd slot channels for the passage of hot and cold heat transfer agents , pressure plates, inlet and outlet fittings for heat carriers, tightening pins connecting the pressure plates to each other along their contours, characterized in that thin heat-conducting sheets and pressure plates are disc-shaped, holes for the passage of heat carriers in thin heat-conducting sheets and fittings for heat carriers are arranged in pairs in the central and peripheral parts of the disks, large spacers of elastic material between thin heat-conducting sheets are made in the form of a continuous concentric winding with the formation of spiral slotted channels for coolants, at the ends of the spirals In the slotted channels, there are flow channels that adjoin the edges of the thin heat-conducting sheets around the holes; in addition, additional tightening pins are installed, located in the holes of the thin heat-conducting sheets. 2. A disk heat exchanger according to claim 1, characterized in that gaskets made of elastic material are located on the planes of the flow channels. 3. A disk heat exchanger according to claim 1, characterized in that grooves are made on the thin heat-conducting sheets to accommodate flow channels, large and small gaskets made of elastic material. 4. A disk heat exchanger according to claim 1, characterized in that the thin heat-conducting sheets have discrete roughness in the form of protrusions and depressions. 5. A disk heat exchanger according to claim 1, characterized in that the outer closed rings of the large gaskets are made reinforced.

Images