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What you should know about finned tube heat exchanger?

Usage of fin tube heat exchanger

We believe that everyone must be familiar with the heat exchanger, because it is very common in our lives. It is generally used to cool the air, and sometimes it is used to heat the air as needed. There are many types of heat exchangers. We often see computer heat exchangers, car heat exchangers and so on. But today the Murphy team introduced to you a kind of heat exchanger that is widely used in various fields such as textile, printing and dyeing, petroleum, chemical industry, electric power, etc., that is, finned tube heat exchanger.

Finned tube heat exchanger, you may not know it by listening to the name, because it is mostly used in the industrial field. Finned tube heat exchanger is the main equipment in many heat exchange devices, and its position is very important! The working principle of finned tube heat exchanger is to use refrigerant to cool air, or heat medium to heat air. 

The finned tube heat exchanger achieves the purpose of strengthening heat transfer by adding fins to the ordinary base tube, and can have the heating effect. When heating is needed, it can use high temperature water, steam or high temperature heat transfer oil to heat the air. When it needs to be cooled, it can use low-temperature water, such as chilled water, to cool the air. The finned tube heat exchanger is very popular in the industry, and it is widely used by enterprises.

At present, the steel-aluminum finned tube is more commonly used. According to the editor, this kind of steel-aluminum composite tube heat exchanger works very well. It has many advantages, such as compact and tight structure, large unit heat exchange area and so on. Therefore, this kind of finned tube heat exchanger is widely used and popular among people.

What should we pay attention to when choosing a finned heat exchanger? 

Murphy will give you some suggestions. Of course, the specific matters depend on the specific situation, which is for reference only. If the thermal performance requirements are relatively high, we should choose the high heat transfer coefficient K value, the higher the value, the better the heat dissipation performance; if the economic problem is taken into account, we can choose the metal consumption less Yes, this can reduce costs; if it is more hygienic, we can choose a smooth surface and easy to clean; in terms of service life, finned heat exchangers can choose metal, so that it is not easy to be corroded and damaged. The service life will be longer; then, we should also pay attention to its protection during use, so that its use can be lengthened, and it can bring more convenience to our lives.

Murphy Industrial stainless steel tube aluminum fin heat

The requirements that the finned tube should meet:

1: The convection radiator shall be manufactured according to the approved product drawings and technical documents, and shall comply with the standard requirements.

2: The outer cover of the steel finned tube convection radiator has a back plate and the header is concealed. The steel belt, the outer cover plate and the guard plates at both ends shall meet the requirements of the relevant material standards, and shall have the material quality certificate.

3: The ellipticity of the steel pipe should not be greater than 0.3 mm. It is pointed out that other items of the steel pipe should meet the requirements of GB/T 3092, GB/T 3087, and GB/T 8163.

4: High-frequency welding or other methods to ensure tightness should be used between the steel strip and the steel pipe. JG/’r 3012. 21998

5: The welding surface of steel strips and steel pipes should be free of coatings, rust, pits and other defects and impurities that affect welding quality.

6: Quality requirements of laser welding composite fin tube

The pitch of the fin tube is 6-7 mm, the height of the fin should be greater than 15 mm, the fin inclination angle should not be greater than 80, and the straightness of the fin tube should not be greater than 1.0 m m per meter. For fins using high-frequency welding technology For tubes, the total length of the actual welds at the measurement location of each meter of finned tube should be greater than 85, and the length of uncontinuous welding should not be greater than 50 mm.

7: Welding quality requirements for steel finned tube convection radiators: The butt joint of steel pipes and steel pipes should meet the requirements of GB 151. Welding should meet the requirements of GB/T 985.

8: The steel finned tube convection radiator shall be subjected to water pressure test or air pressure test group by group before adding the outer cover, and the test pressure is 1.5 times of the working pressure.

9: Steel finned tube convection radiator connection pipe thread should meet the requirements of JG.131.

How to increase the heat dissipation capacity of the heat exchanger:

The finned tube heat exchanger is still a shoulder-arm heat exchanger to a certain extent. The main feature of the heat transfer surface is that it has an extended heat transfer surface. Therefore, the heat transfer process is not only a one-time transfer. On the hot surface, but also on the secondary heat transfer surface at the same time.

In addition to the heat of the medium on the high temperature side being poured into the medium on the low temperature side, part of the heat is also transferred along the height of the fin surface, that is, along the height of the fin, there is a partition to pour the heat, and then the heat is convectively transferred to the low temperature side. medium.

When the finned tube heat exchanger is manufactured, its material will have a certain thermal resistance rate to a certain extent. When it is used, it is directly inversely proportional to the heat dissipation. That is to say, the higher the thermal resistance rate, the higher the heat dissipation. The lower. So if you want to increase the heat dissipation of the radiator, you can also start from this aspect, and there should be a significant improvement.

How to maintain the finned tube:

1. Regularly check whether the cleaning of each fin tube is complete, whether there are deposits, coking, scales, etc., and clean it immediately. At the same time, it is necessary to check whether the adhesion between each fin tube and the rubber gasket is tight, and whether the rubber gasket itself is intact, so as to avoid leakage caused by degumming and damage of the rubber gasket.

2. The compression nut and the upper and lower guide rods of the plate heat exchanger should be frequently lubricated with lubricating grease.

3. Special personnel should be responsible for the adjustment of each instrument, and strictly implement the operating procedures for operation and maintenance.

4. When you need to replace the rubber gasket or repair the degummed part, you need to remove the fin tube, put it on the table, remove the old gasket, or use fine sandpaper for the glue traces in the groove of the fin tube at the degumming place Wipe it off, then use a solvent such as carbon tetrachloride or trichloroethylene to wipe off the oil stains in the groove, and then wipe the back of the new rubber gasket with fine sandpaper, and also use carbon tetrachloride or trichloroethylene solvent Wipe off the oil stains. 

Then apply a thin layer of glue on both the groove and the back of the rubber gasket, and let it dry a little, so as not to stick to the fingers, but still sticky, insert the rubber gasket into the groove, flatten it around, and apply a layer of talcum powder , Then install the finned tube on the equipment frame and gently clamp it. According to the requirements of the glue manual, it can be put into production and use at intervals.

5. Every time the fin tube is re-tightened, pay attention to the position of the scale during the last pressing, and do not over-press the rubber gasket, which may reduce the service life of the gasket.

6. When replacing the rubber gasket of the fin tube, all the sections must be updated to avoid uneven gaps between the fins and affect the heat transfer effect.

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