CN111457622A

CN111457622A - Double-orifice plate liquid-separating middle-exhausting efficient dry evaporator

Info

Publication number: CN111457622A
Application number: CN202010340281.0A
Authority: CN
Inventors: 钟衡; 江辉民; 陈传宝; 倪龙; 姚杨
Original assignee: Nanjing Wuzhou Refrigeration Group Co ltd; Harbin Institute of Technology
Current assignee: Nanjing Wuzhou Refrigeration Group Co ltd; Harbin Institute of Technology
Priority date: 2020-04-26
Filing date: 2020-04-26
Publication date: 2020-07-28

Abstract

A double-hole plate liquid-separating and middle-exhausting efficient dry evaporator relates to an evaporator. The refrigerant inlet pipe is connected with the gas-liquid mixing pipe through an expansion valve, a liquid separating chamber is arranged at the other end of the gas-liquid mixing pipe and connected with the evaporator box body, a heat exchange pipe is fixed between two vertical plates in the evaporator box body and matched with a fixed baffle plate, the secondary refrigerant outlet pipe and the secondary refrigerant inlet pipe are positioned on the upper side and the lower side of the evaporator box body, a primary liquid separating pore plate is arranged at the corresponding position of the evaporator box body and the liquid separating chamber, a secondary liquid separating pore plate is arranged at the corresponding position of the adjacent vertical plate, the upper partition plate separates out a tail end exhaust chamber, the tail end exhaust pipe and the liquid discharge pipe are communicated with the tail end exhaust chamber, the head end of the upper group of heat exchange pipe is connected with the secondary liquid separating pore plate. The number of the heat exchange pipes of the lower group is reduced, the refrigerant is uniformly distributed, the heat exchange area is fully utilized, and the heat exchange efficiency is high.

Description

Double-orifice plate liquid-separating middle-exhausting efficient dry evaporator

Technical Field

The invention relates to an evaporator, in particular to a double-pore plate liquid-separating and middle-exhausting efficient dry evaporator, belonging to the field of refrigeration equipment.

Background

In the engineering application of the dry evaporator, uneven distribution of the refrigerant can cause that the heat exchange area cannot be fully utilized, so that the heat exchange efficiency is low, and meanwhile, the refrigerant at the outlet of some heat exchange tubes can carry liquid to cause the oscillation of the expansion valve. In a refrigeration system, a refrigerant entering a dry evaporator is a gas-liquid two-phase flow, so that the refrigerant is more difficult to distribute uniformly, which is a technical difficulty existing in the development and application of the dry evaporator.

In order to solve the problem, liquid distributors developed and applied at present mainly include pressure drop type, centrifugal type, liquid storage type, and the like, and related patents also use tube boxes, capillary tubes, Y-shaped tubes, and other structures to carry out liquid separation. However, these techniques do not work well in the practical application of dry evaporators: on one hand, liquid distributors with simple structures such as a liquid storage type distributor have good liquid distribution effect when few branches are used, and are mostly used in heat exchange systems of refrigerant, air and other gas-phase media, but heat exchange tubes of a dry evaporator have numerous branches and are usually used in heat exchange systems of refrigerant, water and other liquid-phase secondary refrigerants, and practical application is limited; on the other hand, some liquid distributors proposed at present are too complex in structure, have the problems of large equipment volume, high manufacturing cost, overlarge pressure loss and the like, and are rarely adopted in engineering application. In addition, the refrigerant two-phase flow type has a large influence on the liquid separation effect of the liquid separator, the liquid separator can better and uniformly distribute the refrigerant with uniform gas-liquid mixture, but under most working conditions, the refrigerant entering the liquid separator is not uniformly mixed, and the use effect of the existing liquid separator is also influenced.

Therefore, the problem of uneven distribution of refrigerant in each branch of the dry evaporator in engineering application is not well solved by the existing liquid separation technology. In addition, the dryness of the refrigerant in the heat exchange tube is too high or too low to be beneficial to heat exchange, and the heat exchange tube of the existing dry evaporator is usually low in dryness of an inlet section (high in liquid-phase refrigerant content) and high in dryness of an outlet section (basically free of liquid-phase refrigerant), so that the heat exchange efficiency of the parts is low.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides the efficient dry evaporator with double-pore plate liquid separation and intermediate exhaust from the perspective of practical engineering application.

In order to achieve the purpose, the invention adopts the following technical scheme: a high-efficiency dry evaporator with double-pore plate liquid separation and intermediate exhaust comprises a refrigerant inlet pipe, a gas-liquid mixing pipe, a liquid separation chamber, an evaporator box body, a heat exchange pipe and baffle plates, wherein the refrigerant inlet pipe is connected with one end of the gas-liquid mixing pipe through an expansion valve, the other end of the gas-liquid mixing pipe is fixedly provided with the liquid separation chamber, the liquid separation chamber is fixedly connected with the upper part of the outer wall of the evaporator box body, two vertical plates are arranged on two sides in the evaporator box body, the heat exchange pipe is fixedly arranged between the two vertical plates, a plurality of baffle plates are matched and fixed at the middle position of the heat exchange pipe, the outer wall of the evaporator box body is provided with a tail end exhaust pipe, a liquid discharge pipe, a secondary refrigerant inlet pipe and a secondary refrigerant outlet pipe, the secondary refrigerant outlet pipe and the secondary refrigerant inlet pipe, the heat exchange tubes are divided into an upper group of heat exchange tubes and a lower group of heat exchange tubes, the number of the heat exchange tubes is smaller than that of the heat exchange tubes in the upper group, the head ends of the heat exchange tubes in the upper group are fixedly connected with the openings of the secondary liquid separating pore plates one by one, the lower partition plate is fixed between the far vertical plate and the inner wall of the evaporator box body to divide the upper part of the heat exchange tubes into a middle exhaust chamber, and the middle exhaust tube, the tail ends of the heat exchange tubes in the upper group and the head ends of the heat exchange tubes in the lower group are communicated with the middle exhaust chamber.

Compared with the prior art, the invention has the beneficial effects that:

1. the corrugated gas-liquid mixing pipe can uniformly mix the gas-liquid two-phase refrigerant, liquid separation is performed in a mode that the primary liquid separation pore plate is matched with the secondary liquid separation pore plate, resistance is balanced by adjusting the size of the opening of the primary liquid separation pore plate, the effect of uniform distribution of the gas-liquid two-phase refrigerant is achieved, and the corrugated gas-liquid mixing pipe is simple in structure, easy to manufacture and beneficial to popularization and use;

2. the intermediate exhaust pipe is introduced to discharge excessive gas-phase refrigerant generated in the heat exchange process, so that the influence on heat exchange caused by overhigh dryness of the refrigerant in the heat exchange pipe is avoided, the flow of the refrigerant is reduced after passing through the intermediate exhaust chamber, the number of the heat exchange pipes in the next group can be reduced, the heat exchange area is fully utilized, and meanwhile, the pipes are saved;

3. the tail end exhaust chamber can play the role of a gas-liquid separator in the refrigerating system, and a lower wire mesh arranged at the upper part of the tail end exhaust chamber can separate liquid-phase refrigerant which is not completely evaporated, so that the suction and liquid entrainment of the compressor are prevented;

4. the heat exchanger has the advantages of simple and compact integral structure, small volume and low cost, and can achieve the effects of uniform distribution of the refrigerant, full utilization of heat exchange area and high heat exchange efficiency.

Drawings

FIG. 1 is a schematic elevational view of the present invention;

FIG. 2 is a schematic sectional view taken along line A-A of FIG. 1;

fig. 3 is a schematic sectional view taken along line B-B of fig. 1.

Detailed Description

The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the invention, rather than all embodiments, and all other embodiments obtained by those skilled in the art without any creative work based on the embodiments of the present invention belong to the protection scope of the present invention.

The first embodiment is as follows: as shown in figures 1-3, the invention discloses a double-pore plate liquid-separating and intermediate-exhausting efficient dry evaporator, which comprises a refrigerant inlet pipe 1, a gas-liquid mixing pipe 3, a liquid-separating chamber 6, an evaporator box body, heat exchange pipes 8 and baffle plates 9, wherein the refrigerant inlet pipe 1 is connected with one end of the gas-liquid mixing pipe 3 through an expansion valve 2, the liquid-separating chamber 6 is fixed at the other end of the gas-liquid mixing pipe 3, the liquid-separating chamber 6 is connected and fixed above the outer wall of the evaporator box body, two vertical plates are arranged on two sides in the evaporator box body, the heat exchange pipes 8 are fixed between the two vertical plates, a plurality of baffle plates 9 are fixed in the middle of the heat exchange pipes 8 in a matching manner, a tail end exhaust pipe 16, a liquid discharge pipe 17, a secondary refrigerant inlet pipe 18 and a secondary refrigerant outlet pipe 19 are arranged on the outer wall of the, a plurality of primary liquid separating pore plates 4 are arranged at positions on the outer wall of the evaporator box body corresponding to the liquid separating chambers 6, a plurality of secondary liquid separating pore plates 5 are arranged at positions corresponding to adjacent vertical plates, an upper partition plate 7 is fixed at the bottoms of the pores between the primary liquid separating pore plates 4 and the secondary liquid separating pore plates 5 to separate the lower parts of the pores from a tail end exhaust chamber 14, a tail end exhaust pipe 16 and a liquid discharge pipe 17 are arranged in a penetrating way with the tail end exhaust chamber 14, the tail end exhaust pipe 16 is positioned above the liquid discharge pipe 17, the heat exchange pipes 8 are divided into an upper group and a lower group, the number of the lower group of heat exchange pipes 8 is less than that of the upper group of heat exchange pipes 8, the head ends of the upper group of heat exchange pipes 8 are fixedly connected with the pores of the secondary liquid separating pore plates 5 one by one, a lower partition plate 13 is fixed between the far vertical plates and, the middle exhaust pipe 12, the tail end of the upper group of heat exchange pipes 8 and the head end of the lower group of heat exchange pipes 8 are communicated with the middle exhaust chamber 10.

The second embodiment is as follows: as shown in fig. 1, this embodiment is further described with respect to the first embodiment, in which an upper wire mesh 11 is fixed to the middle exhaust chamber 10 below the middle exhaust pipe 12, and a lower wire mesh 15 is fixed to the end exhaust chamber 14 below the end exhaust pipe 16.

The third concrete implementation mode: as shown in fig. 2, in this embodiment, the diameter of the opening of the primary separating orifice 4 decreases as it is closer to the center of the gas-liquid mixing pipe 3, and conversely, the diameter increases as it is farther from the center of the gas-liquid mixing pipe 3.

The fourth concrete implementation mode: as shown in fig. 2 and 3, the present embodiment is a further description of a third embodiment, and the tube diameter of the lower group of heat exchange tubes 8 is smaller than the tube diameter of the upper group of heat exchange tubes 8.

The fifth concrete implementation mode: as shown in fig. 2, in this embodiment, the openings of the secondary liquid-separating pore plate 5 and the primary liquid-separating pore plate 4 are arranged in a staggered manner, which is further described in the first embodiment.

The sixth specific implementation mode: as shown in fig. 1 and 2, in the present embodiment, the first embodiment is further described, and the gas-liquid mixing pipe 3 is a corrugated pipe in outer shape.

Referring to fig. 1 to 3, a refrigerant enters from a refrigerant inlet pipe 1, is changed into a gas-liquid two-phase flow by the throttling action of an expansion valve 2, is uniformly mixed by a gas-liquid mixing pipe 3, enters a liquid separation chamber 6, is uniformly distributed by a primary liquid separation orifice plate 4 and a secondary liquid separation orifice plate 5, enters an upper group of heat exchange pipes 8, and starts heat exchange in a first stage. The opening diameters of the primary liquid separation pore plate 4 and the secondary liquid separation pore plate 5 can be designed according to actual needs, so that the refrigerant is uniformly distributed. The sizes of the openings on the primary liquid-separating pore plate 4 are not consistent, the diameter of the opening close to the central axis of the gas-liquid mixing pipe 3 is smaller, the diameter of the opening far away from the central axis of the gas-liquid mixing pipe is larger, and the uniformity of refrigerant distribution is adjusted by balancing resistance through the sizes of the openings. The number of the holes of the secondary liquid separating pore plate 5 is the same as that of the heat exchange tubes 8 in the upper group, and the holes are connected in a one-to-one correspondence manner to separate the refrigerant. The refrigerant enters the middle exhaust chamber 10 after the heat exchange of the first stage, under the action of gravity and the upper wire mesh 11, the gas-liquid two-phase refrigerant is separated, the gas-phase refrigerant is discharged from the middle exhaust pipe 12 at the upper part and returns to the compressor, and the liquid-phase refrigerant and part of the gas-phase refrigerant enter the lower group of heat exchange pipes 8 again from the lower part to perform the heat exchange of the second stage. An intermediate exhaust pipe 12 is introduced to avoid the influence of excessive gas-phase refrigerant in the upper group of heat exchange pipes 8 on heat exchange. It should be noted that the refrigerant flow rate after passing through the intermediate exhaust chamber 10 is reduced, which can reduce the number or pipe diameter of the lower heat exchange tubes 8 and save the pipes, so the number and pipe diameter of the heat exchange tubes 8 in the two heat exchange stages are not completely the same. The upper part of the middle exhaust chamber 10 is provided with an upper wire mesh 11 which plays a role of separating liquid-phase refrigerant and avoids the discharge of excessive liquid-phase refrigerant along with gas-phase refrigerant. After the second stage of heat exchange is completed, it enters the end discharge chamber 14 and is discharged through the end discharge pipe 16 and returned to the compressor. The upper part of the tail end exhaust chamber 14 is also provided with a lower wire mesh 15 which also has the functions of separating liquid phase refrigerant which is not completely evaporated, preventing the liquid from being sucked by the compressor by having the coalescence action on liquid drops, replacing a gas-liquid separator arranged in front of the compressor in a refrigeration system, and discharging the separated liquid phase refrigerant by a liquid discharge pipe 17. The secondary refrigerant enters the evaporator box body from the secondary refrigerant inlet pipe 18, flows through the surfaces of the heat exchange pipes 8 under the guide action of the baffle plates 9, exchanges heat with the heat exchange pipes 8 and finally flows out from the secondary refrigerant outlet pipe 19.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. The high-efficiency dry evaporator comprises a refrigerant inlet pipe (1), a gas-liquid mixing pipe (3), a liquid separating chamber (6), an evaporator box body, heat exchange pipes (8) and baffle plates (9), wherein the refrigerant inlet pipe (1) is connected with one end of the gas-liquid mixing pipe (3) through an expansion valve (2), the liquid separating chamber (6) is fixed to the other end of the gas-liquid mixing pipe (3), the liquid separating chamber (6) is fixedly connected with the upper portion of the outer wall of the evaporator box body, two vertical plates are arranged on two sides of the inner portion of the evaporator box body, the heat exchange pipes (8) are fixed between the two vertical plates, a plurality of baffle plates (9) are fixed to the middle position of each heat exchange pipe (8) in a matched mode, a tail end exhaust pipe (16), a drain pipe (17), a secondary refrigerant inlet pipe (18) and a secondary refrigerant outlet pipe (19) are arranged on the outer wall of the evaporator box body, and the Both sides, its characterized in that: a plurality of openings which are primary liquid separating pore plates (4) are arranged at positions corresponding to the liquid separating chambers (6) on the outer wall of the evaporator box body, a plurality of openings which are secondary liquid separating pore plates (5) are arranged at positions corresponding to adjacent vertical plates, an upper partition plate (7) is fixed at the bottom of the opening between the primary liquid separating pore plates (4) and the secondary liquid separating pore plates (5) to separate the lower part of the opening into a terminal exhaust chamber (14), the terminal exhaust pipe (16) and the liquid discharge pipe (17) are both arranged in a penetrating way with the terminal exhaust chamber (14), the terminal exhaust pipe (16) is positioned above the liquid discharge pipe (17), the heat exchange pipes (8) are divided into an upper group and a lower group, the number of the lower group of heat exchange pipes (8) is less than that of the upper group of heat exchange pipes (8), the head ends of the upper group of heat exchange pipes (8) are fixedly connected with the openings of the secondary liquid separating pore plates (5) one by one, a, and a middle exhaust pipe (12) is further arranged above the outer wall of the evaporator box body, and the middle exhaust pipe (12) and the tail end of the upper group of heat exchange pipes (8) and the head end of the lower group of heat exchange pipes (8) are communicated with the middle exhaust chamber (10).

2. The double-orifice plate liquid-separating intermediate-exhausting efficient dry evaporator according to claim 1, characterized in that: an upper wire mesh (11) is fixed in the middle exhaust chamber (10) and below the middle exhaust pipe (12), and a lower wire mesh (15) is fixed in the tail end exhaust chamber (14) and below the tail end exhaust pipe (16).

3. The double-orifice plate liquid-separating intermediate-exhausting high-efficiency dry evaporator according to claim 1 or 2, characterized in that: the diameter of the opening of the primary liquid separation pore plate (4) is smaller when the opening is closer to the center of the gas-liquid mixing pipe (3), and conversely, the diameter of the opening is larger when the opening is farther from the center of the gas-liquid mixing pipe (3).

4. The double-orifice plate liquid-separating intermediate-exhausting efficient dry evaporator according to claim 3, characterized in that: the pipe diameter of the lower group of heat exchange pipes (8) is smaller than that of the upper group of heat exchange pipes (8).

5. The double-orifice plate liquid-separating intermediate-exhausting efficient dry evaporator according to claim 1, characterized in that: the secondary liquid separation pore plate (5) and the primary liquid separation pore plate (4) are arranged in a staggered mode.

6. The double-orifice plate liquid-separating intermediate-exhausting efficient dry evaporator according to claim 1, characterized in that: the gas-liquid mixing pipe (3) is a corrugated pipe in shape.