Precautions for using stainless steel finned tubes

2025-07-17

The following are the key precautions for using stainless steel finned tubes, including comprehensive selection, installation, operation, and maintenance requirements throughout the entire process: 1. Material and environmental compatibility Chloride ion environment (such as coastal and chemical industries): 316/316L stainless steel containing molybdenum (with a molybdenum content of 2% -3%) should be selected, which has a pitting corrosion resistance that is more than three times higher than 304; When the chloride ion concentration is greater than 50ppm, 304 is prohibited. High temperature>800 ℃: choose 310S (Cr25Ni20), long-term temperature resistance 1080 ℃; Avoid operating 316L at temperatures exceeding 900 ℃ (accelerated thickening of the oxide layer). Low temperature condition (-196 ℃): 304/316 can meet the requirements, but the flow rate of the medium needs to be controlled to prevent frost heave and rupture. 2. Process structure selection High frequency welding fins: The fusion rate of welding points should be ≥ 90%, and the tensile strength should be 450-550MPa; Whole rolled fins: no weld structure, suitable for strong vibration or high-temperature thermal cycling scenarios....

Cleaning techniques for copper finned tubes

2025-07-17

1、 Basic cleaning process 1. Power outage and cooling Close the heat medium valve and disconnect the power supply, and wait for the tube temperature to drop to room temperature (usually taking ≥ 2 hours) to prevent burns or the evaporation of cleaning agents. /2. Pre dust removal treatment Use a soft bristle suction head of a vacuum cleaner to remove floating dust along the gaps of the fins, or use compressed air with a pressure of ≤ 0.4MPa to blow in the direction of the airflow (the pressure of the aluminum fins should be ≤ 0.2MPa). 2、 Taboos and protective measures Prohibit strong corrosive agents: Strong acids such as hydrochloric acid and nitric acid can cause copper pipes to corrode and puncture; Carbon tetrachloride cleaning may cause refrigerant system failure. Mechanical operation specifications: Special fin comb is used for fin correction, and knocking or scratching with hard objects is prohibited When flushing with water, the angle of the spray gun should be kept at 30 °, and the high-pressure water pressure should be ≤ 50MPa Drying and rust prevention: After cleaning, ventilate and dry for at least 4 hours, or blow with cold air; Long term shutdown of nitrogen sealing (humidity ≤ 50%)...

Key maintenance points for embedded finned tubes

2025-07-17

The maintenance of embedded finned tubes should focus on their structural characteristics (fins embedded in the grooves of the base tube), and develop specifications based on anti detachment, anti-corrosion, and sealing requirements. The core points are as follows: 1、 Fin cleaning and anti blocking 1. Dust cleaning Use compressed air (pressure ≤ 0.4MPa) to blow in the direction of airflow to avoid high pressure damage to the root fitting of the fins; Stubborn oil stains should be wiped with a neutral cleaning agent soft cloth, and hard objects such as wire brushes should be avoided to prevent fin deformation or groove detachment. High dust environments (such as food drying and textile workshops) need to be cleaned weekly, while ordinary environments should be cleaned once a month to prevent dust accumulation and reduce heat exchange efficiency by more than 20%. 2. Anti scaling measures inside the pipe The water system should be acid washed every 3-6 months (citric acid concentration ≤ 5%), and thoroughly rinsed until neutral after cleaning; Regularly check the drain valve of the steam system to prevent scale from blocking the pipeline. 2、 Structural integrity check 1. Fin fitting status Visually inspect the root of the fins monthly for looseness and warping, especially under high temp...

Processing specifications for spiral wound finned tubes

2025-07-17

The processing specifications for wrapped finned tubes cover key aspects such as material handling, winding process, welding control, and quality inspection. The specific technical standards are as follows: 1. Material selection for pipes and fins Pipe material: 20 # carbon steel seamless pipe is used for high temperature and high pressure environments, and 304/316L stainless steel pipe is selected for corrosion-resistant scenarios; Wall thickness tolerance ± 10%, outer diameter deviation ≤ 0.3mm. Fin strip: commonly used aluminum strip (0.3mm thick) or steel strip (0.8-1mm thick ± 0.05mm), with a width determined by the design (such as 20mm ± 0.3mm), and a smooth and burr free surface. 2. Surface treatment Shot blasting and rust removal of carbon steel pipes (speed 80m/s), acid pickling and passivation of stainless steel pipes (soaking in 10% nitric acid solution for 15 minutes). Fin strip leveling treatment, with a flatness error of ≤± 0.5mm/m, and no burrs on the edges after cutting....

Key points for installing welded finned tubes

2025-07-17

The installation of welded finned tubes must strictly follow the process specifications to ensure heat exchange efficiency and equipment safety. The core points are as follows: 1、 Pre installation inspection 1. Quality acceptance Check the appearance of the finned tube for deformation, ensure that the fins are not loose or detached, and ensure that there are no pores or cracks in the welds. If necessary, perform radiographic testing. Check whether the material certificates (such as 316L stainless steel and galvanized layer thickness of carbon steel) meet the corrosion resistance requirements of the working medium. 2. Environment and tool preparation The installation environment should be dry and ventilated, avoiding corrosive gases; Tools include level gauges, torque wrenches, and specialized lifting equipment. 2、 Installation process control 1. Positioning and fixation Levelness control: During installation, calibrate with a spirit level with a deviation of ≤ 2mm/m to avoid uneven flow of heat medium causing local overheating. Support bearing capacity: The support spacing is ≤ 1.5m, and it needs to withstand 1.5 times the operating weight load. Large pipe groups need to be equipped with anti sway supports. 2. Pipeline system integration Reduce the number of right angled bends in t...

On which side should the fins of a finned tube heat exchanger be installed

2025-07-17

In the design of finned tube heat exchangers, the installation position of the fins directly affects the heat transfer efficiency, and the fins should be installed on the side with a smaller convective heat transfer coefficient (α). The thermal resistance on this side is relatively high, and increasing the surface area of the fins can significantly reduce the overall thermal resistance and balance the difference in heat transfer capacity on both sides; On the contrary, the side with a larger alpha has lower thermal resistance, and the effect of adding fins is limited. Example: Boiler economizer: The flue gas side alpha (about 50 W/(m ² · K)) is much smaller than the water side alpha (>5000 W/(m ² · K)), and fins need to be added to the flue gas side. Air cooler: The air side alpha (about 100 W/(m ² · K)) is lower than the liquid alpha inside the tube (>1000 W/(m ² · K)), and the fins should be placed on the air side....

Working principle and function of economizer

2025-07-17

The economizer is an energy-saving device that preheats boiler feedwater by recovering waste heat from the tail flue gas of the boiler. Its working principle and function are as follows: 1、 Working principle 1. Heat exchange process High temperature flue gas (usually 250-350 ℃) flows outside the serpentine tube bundle of the economizer, and boiler feedwater flows in the opposite direction inside the tube, absorbing heat from the flue gas through the tube wall and raising the water temperature to near saturation temperature (some designs allow partial boiling of water). The flue gas temperature drops to 100-150 ℃ before being discharged. • Reverse flow design: Smoke and water flow in reverse to maximize heat transfer temperature difference. •Material selection: commonly used carbon steel pipes (with fins for enhanced heat transfer) or cast iron pipes (for low-pressure boilers). 2. Operation protection mechanism During the start-up phase, the water flow is maintained through a recirculation pipeline to prevent local overheating and vaporization; Automatically cut off the water flow during shutdown to avoid dry burning of the empty pipe. 2、 Core role 1. Energy saving and efficiency improvement •Reduce the exhaust temperature by more than 100 ℃, reduce heat loss by 5% -15%, a...

Application of serrated finned tubes

2025-07-17

1、 Industrial thermal management system 1. Petrochemical and Energy Sector Petroleum refining: used as a heat exchanger in atmospheric and vacuum distillation, catalytic cracking and other units to process high-temperature oil and gas (300-600 ℃), with a corrosion-resistant design that can resist sulfide corrosion. Power plant waste heat recovery: The waste heat of flue gas is recovered in the tail flue of the boiler, and the toothed structure improves the heat transfer efficiency by more than 20%, reducing the exhaust gas temperature to below 150 ℃. Chemical reaction temperature control: Control the polymerization and synthesis reaction temperature, stainless steel material is resistant to acid and alkali corrosion, ensuring continuous production safety. 2. Metallurgy and Manufacturing Industry Continuous casting cooling system: Spray cooling is applied to high-temperature steel billets, and serrated fins enhance water flow disturbance, resulting in a 30% increase in cooling efficiency compared to ordinary finned tubes. Industrial kiln waste heat utilization: Recovering furnace exhaust gas heat to preheat combustion air, with an annual energy saving rate of up to 15% -25%. 2、 Refrigeration and air conditioning system 1. Large scale refrigeration equipment Central air conditioning condense...