JP2907881B2 - Precooler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is effective for a heat exchanger of a single-stage oil-free screw compressor.

[Prior Art] The conventional pre-cooler of a single-stage oil-free screw compressor has a structure of a pre-cooler as a primary cooler of the compressor. An air passage is fixed by both ends of a pre-cooler shell. Was excessively added.

[Problems to be solved by the invention]

In the above prior art, since the air passage pipe in the precooler was fixed at both ends, the air entering the precooler was 320 to 350.
Thermal expansion of pipe caused by high temperature air of ℃
No consideration is given to reducing thermal stress, and there is a problem in that the pipe in the air passage has a strength problem and the life of the precooler is short.

An object of the present invention is to alleviate excessive thermal stress caused by thermal expansion of a high-temperature precooler and to improve the life of the precooler.

[Means for solving the problem]

In order to achieve the above object, in a pre-cooler of a single-stage oil-free compressor which is provided on a downstream side of a compressor main body and cools a gas flowing out of the compressor main body, a discharge port for discharging a coolant to a side surface is provided. The formed cylindrical shell, one end side of which is connected to an outlet provided outside the shell through the end face of the cylindrical shell and fixed to the end face of the shell, and the other end of which is the first U A first air passage pipe extending in the axial direction of the shell connected to the pipe, and one end fixed to the other end face of the shell having an inlet hole through which a coolant flows, and a shell penetrating the end face. A second air passage pipe extending in the axial direction of the shell connected to an inlet provided outside and having the other end connected to a second U-shaped pipe; the first and second air passage pipes;
A third air passage pipe extending between the other ends of the U-shaped pipes and extending in the axial direction of the shell, forming an S-shaped air passage from the outlet to the inlet. A U-shaped air cooler branching from the external position of the shell of the air passage pipe and penetrating through the outlet end surface of the shell and extending in the axial direction of the shell, and the other end of the air cooler is provided at the outlet side of the shell. The first, second and third air passage pipes penetrating the end face and forming the S-shaped air passage portion are arranged in a triangular shape in a cross section perpendicular to the air flow direction. Is what it is.

Further, in order to make the structure of the precooler compact, the precooler shell is arranged in such a manner that the shape connecting the centers of the three pipes of the air passage pipes in the precooler is triangular and has a three-pass air passage. The structure is such as to prevent the size from becoming large.

[Action]

The compressor pre-cooler of the present invention has
It has three pipes with a letter shape.

That is, both ends of the two pipes on both sides are fixed to the ends of the precooler shell. The central one is connected to the two pipes on both sides by U-bends having a U-shaped top and bottom. High-temperature air flows into the air inlet of the precooler at 320 to 350 ° C, and is cooled in the precooler to about 200 ° C.

Further, the air passage pipe is externally cooled by a cooling medium such as cooling water, and the temperature difference between the air passage pipe at the inlet and the outlet of the precooler is as large as about 100 deg. Although there is thermal expansion due to this, this thermal expansion is generated in two directions of the U-shape which is not fixed, and free thermal expansion is generated at the U-shaped portion, so that the fixed ends of the inlet and the outlet of the air passage pipe are formed. In order to prevent the generation of excessive thermal stress, the life of the precooler can be greatly improved.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS.

FIG. 2 shows the configuration of an air-cooled single-stage oil-free screw compressor.

The compressed air flows from the suction filter 1 into the atmosphere and is sucked into the compressor body 3 via the suction throttle valve 2. The pressure is raised to a predetermined pressure in the compressor main body 3 and the air temperature becomes as high as 320 to 350 ° C. This is cooled to about 200 ° C. by the pre-cooler 7 and enters the after-cooler 10 via the check valve 9. About 55 ° C in aftercooler 10
Then, a part of the drain is separated by the drain separator 11, discharged from the discharge port 12, and provided as required. When the compressor is not loaded, the suction throttle valve 2 is closed. Check valve 9
The air is cooled to about 100 ° C. or less by the blower cooler 8 and discharged to the atmosphere by the discharge pipe 16.

The cooling system is cooled by a coolant (coolant). The coolant is filled in the coolant pipe, and the coolant is sent by the coolant pump 13 into the shell of the pre-cooler 7 and into the jacket of the compressor body 3.
Heat is exchanged with the compressed air and the compressor body, and the coolant becomes hot. The high-temperature coolant is cooled by the coolant cooler 14 and the cooling fan 15 and is again cooled by the coolant pump 13.
Circulated and used.

Next, the structure of the precooler of the present invention will be described with reference to FIGS. 1, 3 and 4. FIG.

 FIG. 1 shows a configuration diagram of the precooler 7.

The high-temperature compressed air discharged from the compressor body 3 enters the pre-cooler 7 from the pre-cooler inlet 17 and enters the air passage pipe.
The heat is exchanged with the coolant in the pre-cooler shell 18 through the U-shaped portion 25, the air passage pipe 23, the U-shaped portion 25, and the air passage pipe 24 to be cooled to about 200 ° C. The coolant enters the precooler shell 18 from the lower coolant inlet 20 of the precooler shell 18 and is sent to the coolant cooler 14 from the coolant outlet 21.

In the structure of the precooler 7 of the present invention, as shown in FIG. 2, three air passage pipes 22, 23, 24 are connected using two U-shaped portions 25. The inlet and outlet portions are fixed to the end face of the precooler shell 18, the inlet fixing portion 26, and the outlet fixing portion 27. At the inlet and outlet of the precooler 7, there is a temperature difference of about 150 deg in the air temperature, and there is also a temperature difference of about 100 deg in the average temperature difference of the pipes. The thermal expansion caused by this is expanded in the direction of the two U-shaped portions 25 so as to be free extension, so that the thermal stress on the inlet fixing portion 26 and the outlet fixing portion 27 is reduced.

FIG. 3 shows a sectional view of the precooler. The three air passage pipes 22, 23, 24 were arranged such that the center of the air passage pipes formed a triangle as shown in FIG. With such a triangular arrangement, the air passage pipe can be arranged in a smaller precooler shell, and the precooler 7 can be downsized. In the drawing, reference numeral 8 denotes a blower cooler.

〔The invention's effect〕

 According to the present invention, the following effects can be obtained.

(1) The thermal stress applied to the air passage pipe of the precooler is reduced, and the life of the precooler is greatly improved.

(2) Since the air passage pipe is formed in the pre-cooler shell in three passes, the heat transfer area as a heat exchanger increases, and the cooling performance of the pre-cooler also improves.

(3) By arranging three air passage pipes in a triangular shape, the size of the precooler can be reduced.

[Brief description of the drawings]

FIG. 1 is a structural view of a precooler according to an embodiment of the present invention, and FIG.
FIG. 3 is an overall structural view of an air-cooled oil-free screw compressor, FIG. 3 is a front sectional view of the precooler of FIG. 1, and FIG. 4 is a sectional view taken along line AA of FIG. 1 ... suction filter, 2 ... suction throttle valve, 3 ...
Compressor body, 4 ... Motor, 5 ... V-belt, 6 ...
Ga casing, 7 Pre-cooler, 8 Blow-off cooler, 9 Check valve, 10 After-cooler, 11 Drain separator, 12 Discharge port, 13 Coolant pump, 14 Coolant Cooler, 15 ... Cooling fan, 16 ...
... vent pipe, 17 ... precooler inlet, 18 ... precooler shell, 19 ... precooler outlet, 20 ... coolant inlet, 21 ... coolant outlet, 22 ... electric passage pipe 1,
23 ... air passage pipe 2, 24 ... air passage pipe 3, 25
… U-shaped part, 26… entrance fixed part, 27… outlet fixed part.

Claims (1)

(57) [Claims] In a pre-cooler of a single-stage oil-free compressor which is provided downstream of a compressor main body and cools gas flowing out of the compressor main body, a discharge port for discharging a coolant is formed on a side surface. A cylindrical shell (18), and an outlet (19) having one end penetrating through the end face of the cylindrical shell and provided outside the shell
And a first air passage pipe (24) extending in the axial direction of the shell connected to the first U-shaped pipe and having the other end fixed to the end face of the shell, and an inlet hole through which coolant flows. One end is fixed to the other end surface of the shell on which the (20) is formed, and is connected to an inlet (17) provided outside the shell through the end surface, and the other end is connected to the second U.
A second air passage pipe (22) extending in the axial direction of the shell connected to the U-shaped pipe, and a third air pipe connected between the other ends of the first and second U-shaped pipes and extending in the axial direction of the shell. An air passage pipe (23), an S-shaped air passage is formed from the outlet portion to the inlet portion, and further branches off from the outer position of the shell of the first air passage tube, and the outlet side of the shell A U-shaped air cooler (8) extending through the end surface and extending in the axial direction of the shell, the other end of the air cooler penetrating the outlet-side end surface of the shell, and the S-shaped air passage portion; The arrangement of the first, second and third air passage pipes forming a triangular shape in a cross section perpendicular to the direction of air flow.