1. Confirm Basic Working Conditions
First confirm the core operating parameters as the premise of selection.
Clarify the effective volume of the water tank and the reserved flange interface size.
Distinguish cleaning media types: ordinary clean water, weak acid and alkali liquid such as citric acid and caustic soda, high chloride hard water, and strong oxidizing cleaning liquid containing sodium hypochlorite.
The conventional operating temperature is between 25℃ to 60℃, and the special working condition does not exceed 80℃. Most water tanks are under normal pressure and low pressure conditions.
Confirm the installation method: flange mounting on the side or bottom of the water tank.
2. Material Selection of Heating Tube
Select materials according to the corrosion degree of the medium.
Choose 304 stainless steel for ordinary clean water and slightly weak alkali cleaning environment.
For daily ultrafiltration acid-base cleaning and water with common chloride ions, 316L stainless steel is the first choice. It is corrosion resistant, scale resistant and suitable for most ultrafiltration cleaning water tanks.
Use TA2 titanium alloy for harsh working conditions with high chloride ions and strong acid and alkali.
Choose Hastelloy for cleaning media containing strong oxidants such as sodium hypochlorite and hydrogen peroxide.
201 stainless steel and ordinary carbon steel are prohibited, as they are easy to corrode, perforate, leak water and cause electric leakage.
3. Power and Surface Load Selection
Match power according to water tank volume. Normally configure 10 to 15 kilowatts per cubic meter of cleaning water. Choose higher power for fast temperature rise, and lower power only for constant temperature and heat preservation.
Strictly control the surface load to prevent scaling and tube burnout. Keep the surface load of 304 stainless steel at a low level, 316L at a moderate level, and further reduce the surface load for titanium alloy and special alloy. Ultrafiltration water quality is prone to scaling, high surface load is not allowed, otherwise the heating tube will be easily scaled and burned out.
4. Flange Specification and Tube Structure Selection
Common flange sizes are DN50, DN80 and DN100, which directly match the original interface of the water tank. The pressure grade of PN10 is enough to meet the working conditions of the water tank.
The material of the flange plate must be consistent with the heating tube body to avoid electrochemical corrosion caused by different metals.
Priority is given to U-type combined structure for the tube body. Use extended tube body for side installation and sunken tube body for bottom installation. Ensure the tube is fully immersed in water during operation to avoid dry burning.
5. Electrical and Safety Configuration Selection
Prioritize 380V three-phase power supply for industrial sites, and 220V single-phase power supply for low-power working conditions.
It must be equipped with temperature measuring probe, over-temperature protection and dry-burning prevention temperature control. An external temperature control cabinet can be connected to realize automatic start and stop of constant temperature of the water tank.
For humid water treatment environment, choose sealed and waterproof junction box, with basic protection up to IP54, and upgrade to IP65 for corrosive and humid environment.
6. Working Condition Margin Adaptation
Reserve about 10% power margin for water tanks with intermittent start and stop. For 24-hour continuous operation, properly reduce the surface load and adjust the power appropriately to extend the service life.
The heat exchange effect of circulating cleaning water tank is better, so the power can be slightly reduced. Appropriately increase the power margin for static standing water tanks.
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Post time: May-20-2026
