JPH01247789A - Heat exchanger for compressor - Google Patents

Abstract

PURPOSE:To relax thermal stress due to thermal expansion to largely lengthen service life of an air-cooling type cooler by a method wherein a cooling pipe connecting an inlet header and an outlet header of a pre-cooler is formed in U-shape, and the cooling pipe is made free toward its top. CONSTITUTION:An air-cooling type pre-cooler which temporarily cools high temperature air exhausted from a compressor main body is connected to an exhaust port of the compressor main body. A cooling pipe 23 which connects between an inlet header 22 and an outlet header 24 of the pre-cooler is formed in U-shape. One end of the cooling pipe 23 is fixed on both headers 22, 24 and the end of the top is set free. This relaxes thermal stress due to thermal expansion, enabling service life of an air-cooling type cooler to be largely lengthened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat exchanger suitable for an air-cooled oil-free screw compressor capable of alleviating heat damage under high-temperature conditions.

[Conventional technology]

Some conventional devices have a structure using a water-cooled precooler (heat exchanger), as described in, for example, Japanese Patent Application Laid-Open No. 60-85286. The water-cooled pre-cooler type oil-free screw compressor has a problem in that depending on the quality of the cooling water, scale accumulates as the operating time elapses, reducing the cooling effect.

[Problem to be solved by the invention]

In the prior art described above, the precooler is cooled by water cooling or liquid cooling. For water-cooled models, scale accumulates over time due to the quality of the cooling water.
The drawback is that the cooling capacity is significantly reduced, which poses a problem in terms of compressor operation management.

On the other hand, liquid-cooled precoolers (those that cool with coolant, etc.) require a large number of cooling devices (coolers and fans) for cooling liquid that exchanges heat through liquid cooling, and are not applicable to small-capacity screw compressors. However, there were drawbacks that made it difficult to apply to large-capacity screw compressors.

The purpose of the present invention is to solve these problems and commercialize a large capacity air-cooled oil-free screw compressor.
We provide an air-cooled precooler suitable for this purpose, especially when the inlet air temperature of the air-cooled precooler is high (approximately 300 to 300℃).
50°C), the purpose is to alleviate thermal stress caused by this temperature difference.

[Rounding method to solve the problem]

An object of the present invention is to provide an air-cooled oil-free screw compressor V by connecting a heat exchanger that primarily cools high-temperature air discharged from the compressor main body to a discharge port of the compressor main body, and The cooling pipe that connects the inlet header and outlet header of the container is U-shaped, and one side is fixed to the header.
This is achieved by creating a structure that does not have a fixed iris.

[Function] The air-cooled precooler is composed of an inlet header, an outlet header, and a cooling pipe connecting these headers.

Since extremely high rNjL air enters the pre-cooler 2, it is necessary to sum the thermal stress due to the temperature difference.For this reason, the pre-cooler's population header and outlet header are placed in the same direction, making them the fixed side. .

The cooling pipe that connects these two headers is made into a U shape, and the inlet part -\
The rudder and exit header are fixed in the same direction. On the other hand,
Since the U-shaped cooling pipe is free toward the top,
Thermal expansion will occur in this direction.

Since the direction of thermal expansion is free and unrestricted, the thermal stress caused by thermal expansion of the precooler as a whole is relaxed, and it can be used as an air-cooled precooler suitable for practical use.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

The overall flow and the positioning of the air-cooled precooler will be explained with reference to FIG.

The flow of compressed air is controlled by the compressor main body 1, which passes air sucked through a filter (not shown) to a predetermined pressure cuff.
Increase the pressure to y/ag. This will give approximately 300 to 350'
The discharged air, which has reached a high temperature of C, enters the air-cooled precooler 8 via the discharge pipe 7. Here, it is cooled to about 150°C, passed through the check valve 9, further cooled to about 50°C by the aftercooler 210, and then discharged. check valve 9ri
This prevents air from flowing backward from the aftercooler tO11g when the compressor 1 is under no load. The compression @1 is driven by the power of the mode 2, which causes the belt 3 to rotate the gear shaft 4 in the gear case 14. The additional gear 5 in the gear case 14 further rotates the compressor main body 1.
Rotate.

A lubrication device is provided to lubricate the gears and bearings (not shown) of the compressor main body 1. An oil pump 16 is attached to the shaft end of the gear shaft 4, and an oil pump d is attached to the lower part of the gear case 14.
The lubricating oil 15 is sucked up by the oil pump 16 and cooled by an air-cooled oil cooler 17, and the lubricating oil is supplied to the bearings and gears of the compressor body 1.

A jacket 11 is arranged around the casing (not shown) of the pressure M1 main body 1, and a coolant (
Flow coolant) to cool the unit. This coolant has a dedicated coolant pump 12Vc! : The coolant is circulated, cooled by the coolant cooler 13, and then used.

Cool D After Cool 210. Oil cooler 17, coolant cooler 13. The air-cooled precooler 8 is cooled by a ventilation fan 19.

The capacity is adjusted by the suction throttle valve 6 in response to load fluctuations of the compressor.

FIG. 2 shows the structure of an air-cooled aftertuck and will be explained with reference to this figure.

High temperature (approx. 300 to 350℃) discharged from the compressor main body 1
) is passed through the discharge pipe 7 to the precooler inlet 21.
Enter the air-cooled precooler. The high-temperature air entering from here is branched from the inlet header 22 to cooling pipes 23, and the high-temperature air inside the pipes is cooled.

The cooled air has a temperature of about 100 to 150°C, is collected from the outlet header 24vC, and is sent from the precooler outlet 25 to the aftercooler 10 via the check valve 9. Further, although the cooling pipe is supported by a support 26, it is not fixed.

The cooling pipe 23 has a U-shaped structure and is fixed to the inlet header 22 and the outlet header 24 in the same direction.

However, the apex direction of the U-shape of the cooling pipe is free to stretch and is not fixed.

With respect to thermal expansion due to the high temperature of the cooling f23, one side has a 7-Lee structure, which has the effect of eliminating excessive thermal stress.

〔Effect of the invention〕

According to the present invention, there are the following effects.

(1) Thermal stress under high-temperature strips is reduced, significantly extending the life of air-cooled coolers.

(2) It is possible to follow the load fluctuations of the compressor, and the thermal stress caused by temperature differences can be directly suppressed.

(3) By using an air-cooled pre-cooler, the heat load on the coolant system is significantly reduced, resulting in a smaller cooler.

[Brief explanation of the drawing]

Figure 1 shows a flow sheet for an air-cooled oil-free screw compressor. FIGS. 2(a), (b), (C) and (d) show the structure of the air-cooled precooler of the present invention. 1...Pressure #1! Rock body 2... Maudle 3.
・・V belt 4・Gear shaft 5・・
Expansion gear 6...Suction throttle valve 7...Discharge piping
8... Air-cooled precooler 9... Check valve 10
...Aftercooler 11...Shakebuto
12... Coolant pump 13... Coolant cooler 14... Gear case 15... Lubricating oil 16... Oil pump 17...-Oil cooler 18... Solenoid valve 19... Ventilation fan 20.
...Exhaust port 21...Precooler population section 22.
...Population Department Hebda 23...Cooling pipe 24...
Outlet part Hebda 25... Precooler outlet part 26
...long boat. 71st inning inferior 2UiJ (α)

Claims (1)

[Claims] In an air-cooled oil-free screw compressor, a heat exchanger that primarily cools high-temperature air discharged from the compressor main body is connected to the discharge port of the compressor main body, and an inlet header and an outlet header of the heat exchanger are connected. A heat exchanger for a compressor, characterized in that cooling pipes connecting the two are U-shaped, one side is fixed to a header, and the other side is not fixed.