CN213873194U

CN213873194U - Air preheater

Info

Publication number: CN213873194U
Application number: CN202022660247.XU
Authority: CN
Inventors: 曲文龙
Original assignee: Lianyungang Youfeng Electric Power Equipment Co ltd
Current assignee: Lianyungang Youfeng Electric Power Equipment Co ltd
Priority date: 2020-11-17
Filing date: 2020-11-17
Publication date: 2021-08-03
Anticipated expiration: 2030-11-17

Abstract

The utility model provides an air preheater, which has high heat energy conversion efficiency and can save more energy; the method is characterized in that: the device also comprises a left lower clapboard (41) and a right upper clapboard (42); the heat exchanger A (43) comprises an upper inlet port (43-1), a lower outlet port (43-2), a finned tube (43-3) and a bent tube (43-4); the upper inlet port (43-1) is arranged at the uppermost end of the heat exchanger A (43); the lower outlet port (43-2) is arranged at the lowest end of the heat exchanger A (43); the finned tube (43-3) is arranged between the upper inlet port (43-1) and the lower outlet port (43-2); the utility model has the advantages that: the heat energy conversion efficiency is high, the energy is saved, the cost of a user can be reduced, the economic benefit is improved, the environmental pollution can be reduced, and the heat energy conversion device has a very beneficial effect on enterprises and the society.

Description

Air preheater

Technical Field

The utility model relates to an air preheater, especially an air heater who adopts steam heat transfer.

Background

The air preheater is waste heat utilization equipment for steam equipment such as a boiler, a steam engine and the like, namely, steam exhausted after acting is converted into hot air by a heat exchanger and supplied to the steam equipment such as the boiler, the steam engine and the like for combustion, so that the combustion cost is reduced, and the energy is saved; however, the conversion efficiency of the steam preheater of the prior art is low, and particularly, a large part of steam is discharged after the steam is converted by the heat exchanger, which indicates that a large part of heat energy is not utilized, so that an air preheater with high conversion efficiency for steam heat exchange is desired.

Disclosure of Invention

The utility model provides an air preheater, its heat energy conversion efficiency is high, can the energy saving more.

The technical proposal of the utility model for solving the technical problem is that: the utility model mainly comprises a preheating chamber (8), a channel B (9), a cylinder B (10), a middle flange B (11), a channel A (20), a cylinder A (21) and a middle flange A

(22) A left lower clapboard (41), a right upper clapboard (42) and a heat exchanger A (43); the method is characterized in that: also comprises a left lower clapboard (41) and a right upper clapboard (42).

The left lower partition plate (41) and the right upper partition plate (42) form a Z-shaped channel.

When air passes through the cylinder B (10) and the channel B (9) from the middle flange B (11), the air enters the preheating chamber (8) from the lower end of the upper right partition plate (42); the air entering the preheating chamber (8) flows from the lower end of the heat exchanger A (43) to the upper end of the heat exchanger A (43) from top to bottom and flows to the upper part of the preheating chamber (8), the air on the upper part of the preheating chamber (8) flows to the channel A (20), the cylinder A (21) and the middle flange A (22) from the upper end of the left lower partition plate (41) for a boiler, and the flow direction of the air is from low to high and is used for lengthening the channel for air circulation.

After steam enters the heat exchanger A (43) from the steam inlet (51), the steam flows to the steam-water outlet (52) from top to bottom through the heat exchanger A (43) gradually, the steam temperature is gradually reduced and condensed, the steam has lower temperature in the heat exchanger A (43) and lower temperature, the condensing efficiency is higher, more water is formed until the steam is completely converted into water and trace steam, and the steam flows out from the steam-water outlet (52); the steam heat is efficiently converted into hot air and water, so that the air preheating efficiency is high, the waste of the steam heat is not discharged, and the purpose of saving energy is achieved.

The utility model has the advantages that: the heat energy conversion efficiency is high, the energy is saved, the cost of a user can be reduced, the economic benefit is improved, the environmental pollution can be reduced, and the heat energy conversion device has a very beneficial effect on enterprises and the society.

Drawings

Fig. 1 is a front view of the structure of the present invention.

Fig. 2 is a left side view of the structure of the present invention.

Fig. 3 is a rear view of the structure of the present invention.

Fig. 4 is a right side view of the structure of the present invention.

Fig. 5 is a plan view of the structure of the present invention.

Fig. 6 is a structural sectional view of the present invention.

Fig. 7 is a heat exchange schematic diagram of the present invention.

Fig. 8 is a steam flow diagram of the heat exchanger a of the present invention.

Fig. 9 is a heat exchange schematic of the prior art.

In the figure, 1, an upper flange A; 2. an upper valve A; 3. lifting lugs; 4. an upper branch pipe A; 5. an upper main pipe; 6. an upper valve B; 7. an upper flange B; 8. a preheating chamber; 9. a channel B; 10. a cylinder B; 11. a middle flange B; 12. a lower flange B; 13. a lower valve B; a lower branch pipe B; 15. a lower main pipe; 16. a support; 17. a lower branch pipe A; 18. a lower flange A; 19. a lower valve A; 20. a channel A; 21. a cylinder A; 22. a middle flange A; 23. an upper through pipe A; 24. a rear valve A is arranged; 25. an upper rear support pipe A; 26. mounting a rear branch pipe A; 27. an upper through pipe B; 28. a rear valve B is arranged; 29. a rear support pipe B is arranged; 30. mounting a rear branch pipe B; 31. an upper branch pipe A; 32. an upper branch pipe B; 33. a lower rear branch pipe A; 34. a rear valve A is arranged; 35. a lower rear branch pipe B; 36. a rear valve B is arranged; a lower branched pipe A; 38. a lower branch pipe B; 39. a lower through pipe A; 40. a lower through pipe B; 41. a left lower baffle plate; 42. a right upper baffle plate; 43, heat exchanger A; 44. steam flow direction; 45. the flow direction of the preheated air; 46. heat exchanger B1; 47. heat exchanger B2; 48. an upper branch pipe B; 49. a lower rear support pipe A; 50. a lower rear support pipe B; 51. a steam inlet; 52. a steam outlet; 43-1. upper port; 43-2. lower outlet port; 43-3. finned tube; 43-4. bending the pipe.

Detailed Description

The first embodiment.

In fig. 1, 2, 3, 4, 5, 6, 8, the present invention includes an upper flange a (1), an upper valve a (2), a lifting lug (3), an upper branch pipe a (4), an upper main pipe (5), an upper valve B (6), an upper flange B (7), a preheating chamber (8), a passage B (9), a cylinder B (10), a middle flange B (11), a lower flange B (12), a lower valve B (13), a lower branch pipe B (14), a lower main pipe (15), a bracket (16), a lower branch pipe a (17), a lower flange a (18), a lower valve a (19), a passage a (20), a cylinder a (21), a middle flange a (22), an upper branch pipe a (23), an upper rear valve a (24), an upper rear branch pipe a (25), an upper rear branch pipe a (26), an upper branch pipe B (27), an upper rear valve B (28), an upper rear branch pipe B (29), an upper rear branch pipe B (30), An upper branch pipe A (31), an upper branch pipe B (32), a lower rear branch pipe A (33), a lower rear valve A (34), a lower rear branch pipe B (35), a lower rear valve B (36), a lower branch pipe A (37), a lower branch pipe B (38), a lower through pipe A (39), a lower through pipe B (40), a heat exchanger A (43), an upper branch pipe B (48), a lower rear branch pipe A (49) and a lower rear branch pipe B (50); the method is characterized in that: the device also comprises a left lower clapboard (41) and a right upper clapboard (42); the heat exchanger A (43) comprises an upper inlet port (43-1), a lower outlet port (43-2), a finned tube (43-3) and a bent tube (43-4); the upper inlet port (43-1) is arranged at the uppermost end of the heat exchanger A (43); the lower outlet port (43-2) is arranged at the lowest end of the heat exchanger A (43); the finned tube (43-3) is disposed intermediate the upper inlet port (43-1) and the lower outlet port (43-2).

The finned tubes (43-3) of the heat exchanger A (43) are transversely arranged and distributed in an up-down multilayer manner.

The finned tubes (43-3) of the heat exchanger A (43) are connected in series.

The finned tubes (43-3) of the heat exchanger A (43) are connected in a way of adopting bent tubes (43-4).

The lower left partition (41) is arranged below the left end of the preheating chamber (8).

The right upper partition plate (42) is arranged above the right end of the preheating chamber (8).

The lower left opening of the preheating chamber (8) is provided with a lower left partition plate (41), and the left part is provided with an upper opening.

The right upper opening of the preheating chamber (8) is provided with a right upper partition plate (42), and the right part is provided with a lower opening.

In fig. 6, the heat exchanger a (43) is arranged in the middle of the preheating chamber (8), the left end is connected with the left lower partition plate (41), and the right end is connected with the right upper partition plate (42); a space is reserved at the upper end of the heat exchanger A (43), the height of the space is not less than 100mm, a space is reserved at the lower end of the heat exchanger A (43), and the height of the space is not less than 100 mm.

The upper end of the preheating chamber (8) is provided with a lifting lug (3), and the lower end is provided with a support (16).

The left end of the preheating chamber (8) is sequentially connected with a channel A (20), a cylinder A (21) and a middle flange A (22)

And (4) connecting in series.

The right end of the preheating chamber (8) is connected with the channel B (9), the cylinder B (10) and the middle flange B (11) in series.

In fig. 1 and 2, an upper branch pipe a (31) is connected to the upper part of the left front wall of the preheating chamber (8), the inner end of the upper branch pipe a (31) is connected with an upper inlet port (43-1) of the heat exchanger a (43), and the outer end is connected with an upper branch pipe a (4); the upper branch pipe A (4) is connected with one end of the upper valve A (2), and the other end of the upper valve A (2) is connected with the upper main pipe (5).

In fig. 1 and 2, a lower branched pipe a (37) is connected to the lower part of the left front wall of the preheating chamber (8), the inner end of the lower branched pipe a (37) is connected with a lower outlet port (43-2) of the heat exchanger a (43), and the outer end is connected with a lower branched pipe a (17); the lower branch pipe A (17) is connected with one end of a lower valve A (19), and the other end of the lower valve A (19) is connected with the lower main pipe (15).

In fig. 1 and 4, an upper branch pipe B (32) is connected to the upper part of the right front wall of the preheating chamber (8), the inner end of the upper branch pipe B (32) is connected with an upper inlet port (43-1) of the heat exchanger a (43), and the outer end is connected with an upper branch pipe B (48); the upper branch pipe B (48) is connected with one end of an upper valve B (6), and the other end of the upper valve B (6) is connected with the upper main pipe (5).

In fig. 1 and 4, a lower branch pipe B (38) is connected to the lower part of the right front wall of the preheating chamber (8), the inner end of the lower branch pipe B (38) is connected with a lower outlet port (43-2) of the heat exchanger a (43), and the outer end is connected with a lower branch pipe B (14); the lower branch pipe B (14) is connected with one end of a lower valve B (13), and the other end of the lower valve B (13) is connected with a lower main pipe (15).

In fig. 1, 2 and 4, and in fig. 1, 2 and 4, an upper flange a (1) is arranged at the left end of the upper branch pipe a (4), and an upper flange B (7) is arranged at the right end; and the left end of the lower branch pipe A (17) is provided with a lower flange A (18).

In fig. 3 and 2, an upper rear branch pipe a (26) is connected to the upper portion of the left rear wall of the preheating chamber (8), the inner end of the upper rear branch pipe a (26) is connected to the upper inlet port (43-1) of the heat exchanger a (43), and the outer end is connected to the upper rear branch pipe a (25); the upper rear support pipe A (25) is connected with one end of the upper rear valve A (24), and the other end of the upper rear valve A (24) is connected with the upper through pipe A (23). The upper through pipe A (23) is connected with the upper main pipe (5).

In fig. 3 and 2, a lower rear branch pipe a (33) is connected to the lower part of the left rear wall of the preheating chamber (8), the inner end of the lower rear branch pipe a (33) is connected with a lower outlet port (43-2) of the heat exchanger a (43), and the outer end is connected with a lower rear branch pipe a (49); lower back stay A (49) is connected with the one end of lower back valve A (34), the other end and the lower siphunculus A (39) of lower back valve A (34) are connected, lower siphunculus A (39) are connected with lower person in charge (15).

In fig. 3 and 4, an upper rear branch pipe B (30) is connected to the upper portion of the right rear wall of the preheating chamber (8), the inner end of the upper rear branch pipe B (30) is connected to the upper inlet port (43-1) of the heat exchanger a (43), and the outer end is connected to an upper rear branch pipe B (29); go up rear branch pipe B (29) and be connected with the one end of last rear valve B (28), the other end of going up rear valve B (28) is connected with last siphunculus B (27), it is connected with last main pipe (5) to go up siphunculus B (27).

In fig. 3 and 4, a lower rear branch pipe B (35) is connected to the lower part of the right rear wall of the preheating chamber (8), the inner end of the lower rear branch pipe B (35) is connected to the lower outlet port (43-2) of the heat exchanger a (43), and the outer end is connected to a lower rear branch pipe B (50); the lower rear support pipe B (50) is connected with one end of the lower rear valve B (36), the other end of the lower rear valve B (36) is connected with the lower through pipe B (40), and the lower through pipe B (40) is connected with the lower main pipe (15).

Example two.

In fig. 7 and 8, the utility model mainly comprises a preheating chamber (8), a channel B (9), a cylinder B (10), a middle flange B (11), a channel a (20), a cylinder a (21), a middle flange a (22), a left lower baffle (41), a right upper baffle (42), a heat exchanger a (43), a steam inlet (51) and a steam outlet (52); the method is characterized in that: the heat exchanger A (43) comprises an upper inlet port (43-1), a lower outlet port (43-2), finned tubes (43-3) and a bent tube (43-4), steam can pass through the upper inlet port (43-1), and gradually flows to the lower outlet port (43-2) from top to bottom through the finned tubes (43-3) and the bent tube (43-4), so that steam heat is converted into hot air and water, and the air in the preheating chamber (8) is preheated.

The upper end port (43-1) of the heat exchanger A (43) is arranged at the upper end, the lower end port (43-2) is arranged at the lower end, the finned tubes (43-3) are arranged from high to low in a layered mode from the upper end port (43-1) to the lower end port (43-2), and the upper layer and the lower layer of the finned tubes (43-3) are connected through bent through tubes (43-4).

The utility model comprises a preheating chamber (8), a channel B (9), a cylinder B (10), a middle flange B (11), a channel A (20), a cylinder A (21), a left lower baffle (41) of the middle flange A (22), a right upper baffle (42), a heat exchanger A (43), a steam inlet (51) and a steam outlet (52); the method is characterized in that: the right side of the preheating chamber (8) is provided with a channel B (9), a cylinder B (10) and a middle flange B (11), and the left side is provided with a channel A (20), a cylinder A (21) and a middle flange A (22); a left lower partition plate (41) for blocking air circulation is arranged at the lower port of the left end of the preheating chamber (8); a right upper partition plate (42) for blocking air circulation is arranged at the upper opening of the right end of the preheating chamber (8), a heat exchanger A (43) is arranged in the middle of the preheating chamber (8), the left end of the heat exchanger A (43) is connected with the left lower partition plate (41), and the right end of the heat exchanger A is connected with the right upper partition plate (42); the upper end of the heat exchanger A (43) is not higher than the upper end of the left lower partition plate (41) by 30mm, and the lower end of the heat exchanger A is not higher than the lower end of the right upper partition plate (42) by 30 mm; the upper part of the preheating chamber (8) is provided with a steam inlet (51) device, and the lower part is provided with a steam-water outlet (52) device.

Example three.

In fig. 7 and 8, the utility model mainly comprises a preheating chamber (8), a channel B (9), a cylinder B (10), a middle flange B (11), a channel a (20), a cylinder a (21), a middle flange a (22), a left lower baffle (41), a right upper baffle (42) and a heat exchanger a (43); the method is characterized in that: also comprises a left lower clapboard (41) and a right upper clapboard (42).

When air passes through the cylinder B (10) and the channel B (9) from the middle flange B (11), the air enters the preheating chamber (8) from the lower end of the upper right partition plate (42); the air entering the preheating chamber (8) flows from the lower end of the heat exchanger A (43) to the upper end of the heat exchanger A (43) from top to bottom and flows to the upper part of the preheating chamber (8), and the air on the upper part of the preheating chamber (8) flows to the channel A (20), the cylinder A (21) and the middle flange A (22) from the upper end of the left lower partition plate (41) and is used for the boiler.

The heat exchanger A (43) comprises an upper inlet port (43-1), a lower outlet port (43-2), finned tubes (43-3) and a bent tube (43-4), steam can pass through the upper inlet port (43-1) and gradually flow to the lower outlet port (43-2) from top to bottom through the finned tubes (43-3), steam heat is converted into hot air and water, and the air in the preheating chamber (8) is preheated.

The waste of the heat of the steam is not discharged, and the purpose of saving energy is achieved.

The upper inlet port (43-1) of the heat exchanger A (43) is arranged at the upper end, the lower outlet port (43-2) is arranged at the lower end, and the finned tubes (43-3) are arranged in a layered mode from high to low from the upper inlet port (43-1) to the lower outlet port (43-2).

The heat exchanger A (43) comprises an upper inlet port (43-1), a lower outlet port (43-2) and a finned tube (43-3), when steam enters the upper inlet port (43-1), the steam gradually flows to the lower outlet port (43-2) from top to bottom through the finned tube (43-3) and a bent tube (43-4), the heat of the steam is gradually transferred to the finned tube (43-3), the temperature is gradually reduced and condensed, the lower the temperature of the steam in the finned tube (43-3) of the heat exchanger A (43), the higher the condensing efficiency is, the more water is formed until the steam is completely converted into water and trace steam, and the steam flows out from the lower outlet port (43-2) of the heat exchanger A (43); the steam heat is efficiently converted into hot air and water, so that the passing air is high in preheating efficiency, the waste of the steam heat is not discharged, and the purpose of saving energy is achieved.

Claims

1. The air preheater comprises an upper flange A (1), an upper valve A (2), a lifting lug (3), an upper branch pipe A (4), an upper main pipe (5), an upper valve B (6), an upper flange B (7), a preheating chamber (8), a channel B (9), a cylinder B (10), a middle flange B (11), a lower flange B (12), a lower valve B (13), a lower branch pipe B (14), a lower main pipe (15), a support (16), a lower branch pipe A (17), a lower flange A (18), a lower valve A (19), a channel A (20), a cylinder A (21), a middle flange A (22), an upper through pipe A (23), an upper rear valve A (24), an upper rear branch pipe A (25), an upper rear branch pipe A (26), an upper through pipe B (27), an upper rear valve B (28), an upper rear branch pipe B (29), an upper rear branch pipe B (30), an upper branch pipe A (31), an upper branch pipe B (32), A lower rear branch pipe A (33), a lower rear valve A (34), a lower rear branch pipe B (35), a lower rear valve B (36), a lower branch pipe A (37), a lower branch pipe B (38), a lower through pipe A (39), a lower through pipe B (40), a heat exchanger A (43), an upper branch pipe B (48), a lower rear branch pipe A (49) and a lower rear branch pipe B (50); the method is characterized in that: the device also comprises a left lower clapboard (41) and a right upper clapboard (42); the heat exchanger A (43) comprises an upper inlet port (43-1), a lower outlet port (43-2), a finned tube (43-3) and a bent tube (43-4); the upper inlet port (43-1) is arranged at the uppermost end of the heat exchanger A (43); the lower outlet port (43-2) is arranged at the lowest end of the heat exchanger A (43); the finned tube (43-3) is disposed intermediate the upper inlet port (43-1) and the lower outlet port (43-2).

2. An air preheater as recited in claim 1, wherein: the left lower partition plate (41) is arranged below the left end of the preheating chamber (8); the right upper partition plate (42) is arranged above the right end of the preheating chamber (8); a left lower opening of the preheating chamber (8) is provided with a left lower partition plate (41), and an upper opening is formed in the left part; the right upper opening of the preheating chamber (8) is provided with a right upper partition plate (42), and the right part is provided with a lower opening.

3. An air preheater as recited in claim 1, wherein: the finned tubes (43-3) of the heat exchanger A (43) are transversely arranged and distributed in an up-down multilayer manner; the finned tubes (43-3) of the heat exchanger A (43) are connected in series; the finned tubes (43-3) of the heat exchanger A (43) are connected in a way of adopting bent tubes (43-4).

4. An air preheater according to claim 1 or 3, wherein: the heat exchanger A (43) is arranged in the middle of the preheating chamber (8), the left end of the heat exchanger A is connected with the left lower partition plate (41), and the right end of the heat exchanger A is connected with the right upper partition plate (42); a space is reserved at the upper end of the heat exchanger A (43), the height of the space is not less than 100mm, a space is reserved at the lower end of the heat exchanger A (43), and the height of the space is not less than 100 mm.

5. An air preheater as recited in claim 1, wherein: the upper end of the preheating chamber (8) is provided with a lifting lug (3), and the lower end is provided with a support (16); the left end of the preheating chamber (8) is connected with the channel A (20), the cylinder A (21) and the middle flange A (22) in series; the right end of the preheating chamber (8) is connected with the channel B (9), the cylinder B (10) and the middle flange B (11) in series.

6. An air preheater according to claim 1 or 5, wherein: the upper part of the left front wall of the preheating chamber (8) is connected with an upper branched pipe A (31), the inner end of the upper branched pipe A (31) is connected with an upper inlet port (43-1) of the heat exchanger A (43), and the outer end of the upper branched pipe A (4) is connected with an upper branched pipe A; the upper branch pipe A (4) is connected with one end of an upper valve A (2), and the other end of the upper valve A (2) is connected with an upper main pipe (5); the lower part of the left front wall of the preheating chamber (8) is connected with a lower branched pipe A (37), the inner end of the lower branched pipe A (37) is connected with a lower outlet port (43-2) of the heat exchanger A (43), and the outer end of the lower branched pipe A (17) is connected with a lower branch pipe A; the lower branch pipe A (17) is connected with one end of a lower valve A (19), and the other end of the lower valve A (19) is connected with the lower main pipe (15).

7. An air preheater as recited in claim 6, wherein: the upper part of the right front wall of the preheating chamber (8) is connected with an upper branch pipe B (32), the inner end of the upper branch pipe B (32) is connected with an upper inlet port (43-1) of the heat exchanger A (43), and the outer end of the upper branch pipe B (32) is connected with an upper branch pipe B (48); the upper branch pipe B (48) is connected with one end of an upper valve B (6), and the other end of the upper valve B (6) is connected with the upper main pipe (5); the lower part of the right front wall of the preheating chamber (8) is connected with a lower branch pipe B (38), the inner end of the lower branch pipe B (38) is connected with a lower outlet port (43-2) of the heat exchanger A (43), and the outer end of the lower branch pipe B (38) is connected with a lower branch pipe B (14); the lower branch pipe B (14) is connected with one end of a lower valve B (13), and the other end of the lower valve B (13) is connected with a lower main pipe (15).

8. An air preheater as recited in claim 1, wherein: the left end of the upper branch pipe A (4) is provided with an upper flange A (1), and the right end is provided with an upper flange B (7); and the left end of the lower branch pipe A (17) is provided with a lower flange A (18).

9. An air preheater as recited in claim 7, wherein: the upper part of the left rear wall of the preheating chamber (8) is connected with an upper rear branch pipe A (26), the inner end of the upper rear branch pipe A (26) is connected with an upper inlet port (43-1) of the heat exchanger A (43), and the outer end of the upper rear branch pipe A (25) is connected with an upper rear branch pipe A; the upper rear support pipe A (25) is connected with one end of an upper rear valve A (24), the other end of the upper rear valve A (24) is connected with an upper through pipe A (23), and the upper through pipe A (23) is connected with the upper main pipe (5); the lower part of the left rear wall of the preheating chamber (8) is connected with a lower rear branch pipe A (33), the inner end of the lower rear branch pipe A (33) is connected with a lower outlet port (43-2) of the heat exchanger A (43), and the outer end of the lower rear branch pipe A is connected with a lower rear branch pipe A (49); lower back stay A (49) is connected with the one end of lower back valve A (34), the other end and the lower siphunculus A (39) of lower back valve A (34) are connected, lower siphunculus A (39) are connected with lower person in charge (15).

10. An air preheater as recited in claim 9, wherein: the upper part of the right rear wall of the preheating chamber (8) is connected with an upper rear branch pipe B (30), the inner end of the upper rear branch pipe B (30) is connected with an upper inlet port (43-1) of the heat exchanger A (43), and the outer end of the upper rear branch pipe B (30) is connected with an upper rear branch pipe B (29); the upper rear support pipe B (29) is connected with one end of an upper rear valve B (28), the other end of the upper rear valve B (28) is connected with an upper through pipe B (27), and the upper through pipe B (27) is connected with the upper main pipe (5); the lower part of the right rear wall of the preheating chamber (8) is connected with a lower rear branch pipe B (35), the inner end of the lower rear branch pipe B (35) is connected with a lower outlet port (43-2) of the heat exchanger A (43), and the outer end of the lower rear branch pipe B (35) is connected with a lower rear branch pipe B (50); the lower rear support pipe B (50) is connected with one end of the lower rear valve B (36), the other end of the lower rear valve B (36) is connected with the lower through pipe B (40), and the lower through pipe B (40) is connected with the lower main pipe (15).