Screw Plug Immersion Heater

A screw plug immersion heater is a compact electric heater designed for direct heating of water, oil, and compatible industrial liquids. U-shape tubular heating elements are welded to a threaded screw plug, allowing the heater to be installed directly into a threaded opening in a tank or vessel.

EaseWise supplies standard and custom screw plug immersion heaters with different thread sizes, immersion lengths, voltage, power ratings, and sheath materials. Available materials include SS304, SS316L, copper, and Incoloy 800 for different liquid types and operating conditions.

Standard configurations are available for common industrial applications, while custom thread sizes, immersion lengths, voltage, power, sheath materials, thermowells, and electrical connections can be manufactured according to customer requirements.

Typical applications include water tanks, solar water heaters, oil tanks, industrial process heating, cleaning tanks, and anti-freeze protection systems.

View our immersion heater product range for additional industrial liquid heating solutions.

Screw Plug Immersion Heater Features

• Threaded Screw-Plug Design: Allows convenient installation and replacement through a threaded tank connection.
• U-Shape Tubular Elements: Provide direct and efficient heating of liquids.
• Liquid Compatibility: Suitable for water, oil, and compatible industrial liquids.
• Multiple Sheath Materials: SS304, SS316L, copper, and Incoloy 800 options are available.
• Reliable Construction: Ni-Cr alloy resistance wire with high-purity MgO insulation supports stable heating performance.
• Flexible Electrical Options: 110V, 220V, 380V, and 415V configurations are available, with single-phase or three-phase options.
• Custom Power: Power ratings from 1 kW to 18 kW can be configured for different heating requirements.
• Temperature Sensing: A thermowell for thermocouple or RTD installation is available as an option.
• Stock and OEM Supply: Standard sizes are available for common replacement applications, with custom production for non-standard requirements.

Technical Parameters

Screw Plug Immersion Heater Stock Reference Sizes

Most high-power and special-length screw plug immersion heaters are OEM custom products. The following are common stock reference models with SS304 sheath material and 220V single-phase configuration.

1″ Screw Plug Immersion Heater

1-1/2″ Screw Plug Immersion Heater

2″ Screw Plug Immersion Heater

Stock Reference Notes

• Immersion length refers to the submerged heating tube length.
• The cold section is located near the screw plug end.
• Stock products do not include a thermowell. Thermowell versions require custom production.
• For oil heating, lower watt density is required to help prevent overheating and burnout.
• Dry burning is strictly prohibited. The heating elements must be fully immersed in liquid during operation.
• For applications above 18 kW, a flanged immersion heater is recommended instead of the screw plug type.

Screw Plug Immersion Heater Applications

Screw plug immersion heaters are suitable for direct heating of water, oil, and compatible industrial liquids where a threaded tank connection is available.

• Water Tank and Solar Water Heater Heating: Domestic and industrial water tanks, as well as auxiliary heating for solar water heating systems.
• Oil Tank Heating: Hydraulic oil, thermal oil, and lubricating oil pre-heating for machinery and industrial equipment.
• Industrial Liquid Process Heating: Clean water, compatible weakly corrosive solutions, cleaning tanks, plating bath media, and other process liquids.
• Anti-Freeze Protection: Maintaining tank liquid temperature and preventing freezing in outdoor equipment and low-temperature environments.

Custom Screw Plug Immersion Heater

EaseWise supports OEM customization for different industrial liquid heating applications. Each screw plug immersion heater can be manufactured according to required dimensions, electrical specifications, drawings, samples, or equipment requirements.

• Custom screw plug thread
• Custom immersion length
• Custom tube diameter
• Custom voltage
• Custom power
• Custom sheath material
• Custom single-phase or three-phase configuration
• Thermowell for thermocouple or RTD
• Junction box
• Silicone gasket
• Earth wire
• OEM production according to drawings or samples

For power requirements above 18 kW, please contact us to discuss a flanged immersion heater solution.

How to Choose a Screw Plug Immersion Heater

Select the heater according to the liquid type, tank size, required temperature, available threaded port, immersion length, voltage, and required heating power. For water heating, a higher watt density can generally be used, while oil and high-viscosity liquids require lower watt density to reduce localized overheating.

Sheath material is also important when selecting a heater for different liquids and operating conditions. See our Immersion Heater Materials & Sheath Selection Guide for a comparison of common sheath materials and their applications.

For additional guidance on selecting immersion heaters for different liquids, see our Immersion Heater for Water, Oil & Chemical Tanks guide.

Technical Reference

For additional technical reference on screw plug immersion heater design, tubular elements, materials, and application considerations, see Watlow’s Screw Plug Immersion Heaters technical information.

Contact EaseWise

For pricing, stock availability, or a custom screw plug immersion heater, please send us your thread size, immersion length, liquid type, voltage, power, quantity, and application.

Amy – Sales
Email:
Amy-Easewise@tzheater.com
WhatsApp:
+86 188 8318 8154

Hanna – Sales
Email:
Hanna-Easewise@tzheater.com
WhatsApp:
+86 173 5163 6811

Stock screw plug immersion heaters are available. Custom thread sizes, immersion lengths, voltage, power, sheath materials, and thermowell configurations are supported.