1 heat pipe and heat pipe heat exchanger

The heat pipe is mainly composed of the working medium inside the pipe shell and the pipe. First, the two substances are required to be chemically compatible, that is, they cannot be chemically reacted, and new substances cannot be generated. This is mainly ensured by the performance index of the working medium. . The working medium of the heat pipe generally has more than ten requirements. Among them, chemical compatibility is the primary performance. In addition, the working medium of the heat pipe must also have safety performance indicators, that is, it must be non-toxic, non-flammable and non-explosive. These requirements are indicators of the working life and safety of heat pipes.

In addition, the current heat pipe performance index is high enough, which is even higher for the heat-increasing heat pipe. The conduction rate of a single-tube heat pipe is very high. The heat transfer rate of metal and non-metal depends on the thermal conductivity of the material, the temperature gradient, and the cross-sectional area orthogonal to the temperature gradient. For example, metal silver is used at 415 W/m 2 . ·K or so, "water steel heat pipe" is several hundred times to thousands of times of silver, and the energy-increasing heat pipe is about 7 times that of "water steel heat pipe". For a single tube heat pipe to have such a high conduction rate, the outer structure design of the tube shell is very important, that is, there must be sufficient convective heat transfer flow rate and a large enough expansion area, that is, a very high heat transfer coefficient, otherwise high enough The conduction rate is difficult to achieve. Specifically, it depends on the flow rate of the hot and cold fluid of the heating section and the cooling section outside the tube relative to the outer fin of the tube and the surface area of ​​the fin. Therefore, the finned surface is generally used outside the heat pipe, that is, the outside of the tube is used. In the form of finned tubes, and as far as possible, the heat pipes are designed with a large fin ratio. The heat pipe heat exchanger is composed of the above-mentioned heat pipe, so it also has the characteristics of long working life and large heat transfer amount.

2 heat pipe heat exchanger working environment

Because the heat pipe heat exchanger has the following main features compared with the conventional heat exchanger: (1) high heat transfer coefficient; (2) large heat transfer or small volume, light weight and compact structure; (3) the isothermal property of the heat pipe is good; (4) It is not easy to corrode, not easy to accumulate dust and scale; (5) It is easy to be disassembled, installed and replaced, and easy to maintain; (6) Each heat pipe is an independent small heat exchanger in the heat pipe heat exchanger, so one If the two heat pipes are broken, the heat pipe heat exchanger will not be affected, and the system related to the heat pipe heat exchanger will not be affected. This is especially important for on-site operation.

Due to the above characteristics, the heat pipe heat exchanger is widely used in practice for waste heat recovery and heat conversion in the fields of petroleum, chemical, natural gas, metallurgy, electric power and small nitrogen fertilizer plants. In the above fields, the environmental conditions of the heat pipe heat exchanger work are generally poor, such as dust accumulation, scaling, thermal resistance, and heat transfer; wear greatly affects the working life of the heat pipe, and the contact thermal resistance greatly affects heat transfer and high temperature. Corrosion and low temperature corrosion affect the safety and life of heat pipes. If the heat pipe heat exchanger can not adapt to the working environment with poor conditions, its work, safety and longevity can not be guaranteed, which is a great waste of the heat pipe heat exchanger. The manufacture of heat pipes and their heat exchangers consumes a large amount of materials, equipment, man-hours and energy, etc. If the service life of heat pipe heat exchangers is doubled, the materials, working hours, energy and costs will be doubled. It is a great waste. If the working life is doubled, the above items are doubled, and that is the real energy-efficient product. After a long working practice and investigation and practical examples, the heat pipe heat exchanger capable of working in the above environment for a long time has only a nickel-based brazed heat pipe heat exchanger.

3 Nickel-based brazing heat pipe heat exchanger

Nickel-based brazing equipment capable of processing nickel-based brazed heat pipes is the hardware in the processing of heat pipe hardware. Nickel-based brazed heat pipe heat exchanger is a heat exchanger composed of many nickel-based brazing heat pipes. Its performance and characteristics are determined by nickel-based brazing heat pipes. The shells are generally carbon steel pipes, and the outer carbon steel wings. The sheet, which is generally a spiral wound fin, is then sintered at a high temperature by a nickel-based brazing apparatus, and has a high heat transfer rate and a high working life.

4 Nickel-based brazing heat pipe and its characteristics

After nickel-based brazing of the heat pipe base pipe and the outer fin: (1) the welding rate of the base pipe and the fin is 100%; (2) the welding portion is smooth; (3) there is no residue in the welding; (4) The thermal resistance of the finned tube is small; the contact thermal resistance is 0, which is significantly less than the thermal resistance of the high frequency welding and the copper alloy welded finned tube; (5) its heat transfer capacity is about 20% higher than that of the high frequency welded finned tube; The finned tubes of the overall rolled steel are equivalent. The nickel-based brazing pipe is uniformly sprayed on the surface of carbon steel by special equipment and process. The alloy is melted in a protective atmosphere and penetrated into the carbon steel matrix by 0.013 to 0.024 mm, and deposited on the surface of the substrate to be about 0.025 mm. The overall formation of a nickel-chromium alloy layer with a thickness of about 0.05mm, the main features: (1) the infiltrated layer of the alloy is uniform, bright, and dense; (2) fundamentally different from the coating and coating, there is no peeling or falling off (3) the surface hardness is about 4 times that of ordinary steel pipe; (4) high temperature and low temperature dew point corrosion; (5) erosion resistance and abrasion, not easy to accumulate dust and scale; (6) can contain acid and alkali, Salt and other corrosive atmospheres in the long-term work; (7) the price is much lower than the stainless steel tube is generally less than 1/4 of the stainless steel tube. According to the above related characteristics, the speed of convective heat transfer can also be increased to increase the heat transfer coefficient, thereby further improving the heat exchange capacity or reducing the structural size.

5 Application of special equipment and process for nickel-based fiber welding

Nickel-based brazing equipment and its process are not only suitable for nickel-based brazing heat pipes, but also for brazing of steel and copper alloy finned tubes, stainless steel finned tubes and various forms of carbon steel finned tubes, and also for corrugation Tubes, as well as nickel-based brazing of steel pipes for special occasions, infiltration into the carbon steel matrix and deposition on the surface of the substrate and overall thickness formation, can achieve the characteristics of nickel-based brazing heat pipes.

Sanitary Strainers/Filters

Sanitary Filter and Strainer are made in stainless steel 316L and size from 1" to 4", by filtering the impurities in the process. Sanitary filter and strainer enables the pipeline produce purified liquids, it is widely used in the equipment of Brewery, Beverage, Biopharmaceutical etc.

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Y-type Sanitary Filter
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Sanitary Strainers–Sanitary Filters– Stainless Steel Sanitary Strainers/Filters:
▪ Size: 1/2″- 4″ (DN10-DN100)
â–ª Material: SS304, SS316L, EN 1.4301, EN 1.4404 etc.
â–ª Standard: 3A, DIN11851, SMS, ISO, RTJ, IDF,etc.
â–ª Connection Type: Clamped, Threaded, Welding
â–ª Sealing Gasket: Silicone, EPDM, PTFE, Buna-N etc.
▪ Temp.: -30°C / -22°F up to +120°C/ +248°F
â–ª Application: Food, Petroleum, Dairy, Pharmacy, Beer, Beverage, Biotech, Cosmetics etc.

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