JPH08173750A - Heat exchanger for dehumidifying compressed air - Google Patents

Abstract

PURPOSE: To obtain a heat exchanger for dehumidifying compressed air without passage resistance and scattering of condensed drainage by installing a thin pipe for sucking drainage which makes the bottom of a main cooling chamber communicate with the bottom of a direction shifting passage independent of an air passage. CONSTITUTION: The middle part or bottom part on the downstream side from it of an inner cylinder 3 is made to communicate with the bottom part of a direction shifting passage 16 by a thin pipe 20 for sucking drainage. The pipe 20 is connected penetrating the bottom to protrude slightly from the wall surface of the bottom. Besides, on the side of the direction shifting passage 16, the end is curved upward in a U-shape. In this way, in spite of the simple structure, drainage deposited in the direction shifting passage can move gently to the bottom of a cooling chamber without scattering again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention fits an inner cylinder into a side plate provided in a cylindrical outer cylinder, and arranges a cooler for a refrigeration cycle in the inner cylinder to form a main cooling chamber. The present invention relates to a heat exchanger in which a plurality of heat transfer pipes are arranged in a space between a cylinder and an inner cylinder to form a precooling chamber.

[0002]

2. Description of the Related Art Generally, in a compressed air dehumidifying heat exchanger having a preliminary cooling chamber and a main cooling chamber, most of the dehumidification of the compressed air is performed by a main cooler in which a cooler by a refrigerator is arranged. Therefore, the drain discharge device for discharging the condensed water is attached to the position where the drain collects in the main cooling chamber. On the other hand, although the dehumidification amount is smaller than that of the main cooler, heat exchange between the compressed air that has been compressed due to the compression of air under atmospheric pressure and the compressed air that has been cooled in the main cooler is performed in the preliminary cooling chamber. As the dew point drops and the minute water droplets in the air fall due to a drop in the flow velocity, water droplets are generated even in the primary heat exchanger, and as a drain, they become drainage in the direction change flow path (bottom of the outer cylinder). Collect. A certain amount of the drain is accumulated at the bottom of the cooling chamber, and a small amount of the drain rises to the bottom of the main cooling chamber and mixes with the drain condensed in the main cooling chamber to form a longitudinal groove or baffle provided at the bottom of the main cooling chamber. It flows down along the notch of the fin and is discharged from the drain drainage device. However, when air is used intermittently on the downstream side of the compressed air dehumidifier, the air flow velocity increases intermittently even in the heat exchanger, and the drain of the direction change passage is rolled up at high speed, and the main cooler There is a risk that the compressed air may pass through and flow into the equipment using compressed air on the downstream side.

A device for preventing this is disclosed in Japanese Patent Laid-Open No.
The one shown in Japanese Patent No. 96122 is known. In the description of the publication, a suction pipe is fixed to the lowermost part of the partition cylinder (inner cylinder) by penetrating, and the direction change passage and the cooling chamber have a normal thickness in which the tip is formed to have a normal thickness. Communication).

[0004]

However, in this type of compressed air dehumidifying heat exchanger, the air passage connecting the direction changing passage and the cooling chamber and the passage for sucking up the drain are the same, so that the water level rises. As a result, the passage area in the direction changing passage decreases and the air flow velocity increases, so that the water in the direction changing passage is sucked up into the cooling chamber. Therefore, there is a problem that the air resistance is inevitably increased and the pressure loss is large. At the same time, since it is a system that sucks up the air together with the air flow, the drain easily scatters again in the compressed air, which may lead to a decrease in dehumidification efficiency.

Therefore, in view of the above problems, the present invention provides compressed air in which the air flow passage is not throttled to generate air resistance, and the drain accumulated in the direction changing flow passage is not scattered again. An object is to provide a heat exchanger for dehumidification.

[0006]

In order to achieve the above object, in the present invention, by providing a drain suction thin tube which communicates with the bottom of the main cooling chamber and the bottom of the direction changing passage, separately from the air passage. Provided is a heat exchanger for compressed air, which has no flow resistance of the compressed air passing therethrough and which does not scatter condensed drainage.

[0007]

In the case where the pre-cooling chamber and the bottom of the main cooling chamber are communicated with each other by the thin tube separately from the air passage as in the present invention, since the main cooling chamber side is the downstream side, the pressure from the direction changing flow path is higher than that of the direction changing passage. Low. Therefore, the drain does not flow by being pushed by the flow of air, but the drain of the direction changing passage is gradually pushed up to the main cooling chamber side by the pressure difference between the main cooling chamber and the direction changing passage, and the other drains are drained. It is mixed and discharged.

[0008]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. 1 and 2 show an embodiment of a compressed air dehumidifying heat exchanger of the present invention, and FIG. 3 is an enlarged view of a portion of a drain suction thin tube of FIG.

Reference numeral 2 is a cylindrical metallic outer cylinder having a compressed air inlet 10 and a compressed air outlet 11, and an inner cylinder 3 is installed in the outer cylinder 2 so as to be substantially concentric. The inner cylinder 3 has a bowl shape, and has a bottomed cylindrical tube bundle plate 6 having a plurality of holes for fitting the heat transfer tubes 8 in the outer peripheral portion, and a plurality of holes having an annular shape for fitting the heat transfer tubes 8 in the outer peripheral portion. The pipe bundle plate 7 is fitted and joined.

In this embodiment, a heat transfer tube 8 is fitted on the outer peripheral surface of the upper portion of the inner cylinder 3 between the tube bundle plates 6 and 7, and the outer circumference of the heat transfer tube 8 is corrugated as shown in the figure. The heat transfer tube 8 is inserted into the convex portion of the corrugated plate so that the concave portion of the corrugated plate 9 is located immediately below the air inlet 10. The corrugated plate 9 has an air passage through the side surface of the convex portion as shown in the figure. The holes 17 are formed, and the air entering from the air inlet 10 is configured to exchange heat with the heat transfer tube 8 in the form of a counter flow. Further, a communication port 12 for communicating with the inside is opened below the tube bundle plate 6 side of the inner cylinder 3.

An evaporator 15 of a refrigeration cycle, which is composed of a refrigerant pipe 14 and baffle fins 18 attached to the refrigerant pipe 14, is mounted in the inner cylinder 3. A drain suction thin tube 20 connects the vicinity of the center of the inner cylinder 3 or the bottom of the inner cylinder 3 and the vicinity of the bottom of the direction changing passage 16. On the inner cylinder 3 side, the drain suction thin tube 20 penetrates through the bottom and is connected, and slightly projects from the bottom wall surface. On the other hand, on the side of the direction changing channel 16, the tip is bent upward in a substantially U shape.

[0012]

In the heat exchanger 1 of the present invention having the above construction, the compressed air introduced from the air inlet 10 is corrugated plate 9.
Through the concave part of the corrugated plate, and the through hole 17 provided on the side surface of the convex part
Flow into the convex portions of the corrugated plates 9 on both sides through the heat transfer tube 8
It is pre-cooled by exchanging heat with the cooling air flowing inside. (At this time, the cooling air flowing in the heat transfer tube 8 and the air flowing in the outer periphery thereof are counterflows.) Next, the air contacting the tube bundle plate 7 is again passed through the passage hole 17 opened in the corrugated plate 9. The cooling air and the heat flowing in the heat transfer tubes 8 flow into the concave portions of the corrugated plate 9 and flow in the direction of the tube bundle plate 6 and enter the convex portions through the passage holes 17 of the corrugated plate 9 to form a flow in the direction of the tube bundle plate 7. Will be exchanged. The compressed air precooled as described above enters the inner cylinder 3 from the communication hole 12 located below the inner cylinder 3 through the concave portion of the corrugated plate 9 and the air passage hole 17, and enters the inner cylinder 3. It is cooled and dehumidified by exchanging heat with the attached evaporator 15. The cooled and dehumidified air enters the heat transfer tubes 8 protruding from the tube bundle plate 7. The cooled and dehumidified air flowing through the heat transfer tube 8 is warmed by heat exchange with the high-heat air flowing around the heat transfer tube 8, and is further discharged from the air outlet 11 as air having a low relative humidity.

The drain generated by dehumidifying in the main cooling chamber 5 in the inner cylinder 3 of the heat exchanger 1 of the present invention is a notch provided at the lower end of the baffle fin 18 extending to the bottom of the inner cylinder 3. After passing through 19, it is pushed by the flow of compressed air, moves downstream, and is discharged to the outside via a drain discharge device 21 that opens to the lower portion outside the tube bundle plate 7. On the other hand, the water condensed in the precooling chamber 4 is pushed downward by gravity or the flow of air and gradually moves downward, and is stored in the direction changing passage 16. At this time, an evaporator provided with an air passage or a baffle fin, in which the angle of the air flow is suddenly changed or the passage area is reduced, between the direction changing passage 16 and the substantially central portion of the main cooling chamber 5 or downstream thereof. Since the structure is such that air resistance such as 15 is generated, a differential pressure is generated between the direction changing passage 16 and the main cooling chamber 5.

Due to this pressure difference, a force that causes the drain to flow from the direction changing passage 16 side to the main cooling chamber 5 side acts. Since the end of the drain suction thin tube 20 on the side of the direction changing passage 16 is substantially U-shaped, drain water remains in the thin tube 20, but the direction changing passage 16 and the inside of the main cooling chamber 5 There is a difference in the water level depending on the pressure difference. That is,
The height difference H between the tip of the U-shaped tube on the folded flow path side and the tip of the U-shaped tube on the main cooling chamber 5 side is the same as the height difference of the water level due to the pressure difference. That is, the pressure difference between both ends of the drain suction thin tube 20 (in the main cooling chamber 5 and in the direction changing passage 16) is set to a height corresponding to (ΔP × specific gravity of drain). Therefore, the U-shaped tube 20 is always balanced in a state where drainage is accumulated.

When the drain collects in the direction changing passage 16 in such a state, the water level difference in the U-shaped pipe 20 is added to the differential pressure, and the drain moves to the main cooling chamber 5 side by that much. The moved drain is pushed by the flow of compressed air at the bottom of the main cooling chamber 5 to move to the downstream side, and is forcibly discharged from the automatic drain discharge device 21 to the outside. Since there is always drain water in the U-shaped tube 20 and acts as a stopper, the direction changing flow path 16
The compressed air inside does not short-pass into the main cooling chamber 5. Further, when compressed air is intermittently used on the downstream side of the compressed air dehumidifier, air corresponding to the compressed air flows in the direction changing passage 16 and the main cooling chamber 5, but in the present invention, the pressure difference is caused. As it is only sucked up, it is less affected by the air flow.

[0016]

As described above, according to the heat exchanger for dehumidifying compressed air of the present invention, in addition to the normal air passage extending from the direction changing passage to the cooling chamber, the thin tube for communicating the two is provided. Although it has a simple structure, it reduces the pressure loss of the drain accumulated in the direction change passage, compared with the conventional one.
It is possible to gently move to the bottom of the cooling chamber without scattering again.

[Brief description of drawings]

FIG. 1 is a structural diagram of an embodiment according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged structural view of a drain suction thin tube portion of FIG. 1.

[Explanation of symbols]

 1 Heat Exchanger 2 Outer Cylinder 3 Inner Cylinder 4 Preliminary Cooling Chamber 5 Main Cooling Chamber 6, 7 Tube Bundle Plate 8 Heat Transfer Tube 9 Corrugated Plate 10 Air Inlet 11 Air Outlet 12 Air Passage 13 Evaporator 14 Refrigerant Piping 15 Cooler 16 Direction Change Flow path 17 Passage hole 18 Baffle fin 19 Groove 20 Drain suction thin tube (U-shaped tube) 21 Drain discharge device

Claims (4)

[Claims] 1. An inner cylinder is fitted and inserted into a side plate provided in a cylindrical outer cylinder, and an evaporator of a refrigeration cycle is arranged in the inner cylinder to form a main cooling chamber, and an outer cylinder and an inner cylinder are formed. A partition plate is provided in the space between the two, and a plurality of heat transfer pipes are arranged in the space on the upper side of the partition plate to form a pre-cooling chamber, and the space on the lower side serves as a direction changing passage, and the direction changing passage and the main cooling chamber In a heat exchanger in which the air passages are communicated with each other, a drain suction thin tube that communicates with the bottom of the main cooling chamber and the bottom of the direction change passage is provided separately from the air passage. Heat exchanger. 2. A drain suction thin tube that communicates the bottom of the main cooling chamber with the bottom of the direction changing passage penetrates through the bottom of the main cooling chamber and opens into the main cooling chamber, and the other end of the direction changing passage. 2. The opening is hung down to the bottom.
A heat exchanger for dehumidifying compressed air as described. 3. The heat exchanger for dehumidifying compressed air according to claim 1, wherein the tip of the drain suction thin tube opened to the direction-changing flow path side is bent upward. 4. The heat exchanger for compressed air dehumidification according to claim 1, wherein the tip of the drain suction thin tube opening to the cooling chamber side is projected from the bottom surface of the cooling chamber.