Pipe Insert Dry Well Immersion Heaters


Electric pipe insert immersion heaters provide a reliable indirect heating solution for tanks and vessels in industrial and process heating applications.  Removal of an immersion heater from a tank for servicing or replacement requires that the tank be drained. When this is impractical, use Durex pipe insert drywell immersion heaters.

Durex Industries manufactures pipe insert heaters by utilizing custom or industry-standard screw plug or flange immersion heaters in various sizes, material options, and power ratings.

How Does a Pipe Insert Heater Work?

The pipe insert, also known as a dry well or bayonet, isolates the immersion heater from tank contents, thereby facilitating easy heater removal without draining the tank.

A standard or custom designed screw plug or flange immersion heater is fitted to the pipe insert or dry well, which in turn, is mated to a coupling or flange nozzle connection on the tank or vessel.

Standard pipe or dry well material is carbon steel, however 304SS, 316SS and Inconel 600 are available.

Design Features of Pipe Insert Heaters

Uses for Pipe Insert Dry Well Heaters

From water tanks to chemical mixers, Pipe insert dry well heaters heat fluids for a variety of thermal heating applications. You also can find drywell heaters in freeze protection and winterizing, large and small storage tanks, and degreasing tanks.

Pipe insert heaters are used to heat a variety of mediums, including:

Benefits of Pipe Insert Heaters

Usually, when a user needs to replace a side insert immersion heater, specifically a screw plug or flange, they first have to drain the tank of its contents.

With a pipe insert heater, the screw plug or flange immersion heater is inserted into a drywell or metal tube, and there is no need to drain the tank. It is easy for the user to remove the actual screw plug or flange heater, while the dry well or metal tube stays inside the tank, therefore containing the fluid inside the tank.

Because the pipe insert heaters are isolated from the contents of the tank, they are kept safe from corrosive materials that could damage the heating element.

Contact Durex Industries for Pipe Insert Dry Well Immersion Heaters

Our experienced engineers can assist you in providing the best and most efficient immersion heating solution required for your application. Durex can also supply temperature sensors and temperature controls for your sensing and control needs.

Factors to Consider When Selecting a Pipe Insert Immersion Heater

  • Electrical rating: voltage, phase, wattage
  • Heater screw plug or flange size
  • Mounting fitting to tank
  • Material requirements
  • Dry well dimensions
  • Electrical enclosure requirements
  • Hazardous location installation
  • Space limitations for installation or heater removal
  • Outdoor or indoor installation
  • Quantity of liquid being heated
  • Temperature control and sensing requirements

Pipe Insert Heater Specifications and options

Heater Specifications

Refer to the Screw Plug Immersion or Flange Immersion heater sections for heater descriptions, technical and ordering information. Heater watt densities are limited to 8 W/in2 for standard designs, however, other watt densities may be recommended based on application requirements.

Mounting and Installation Orientation

Pipe insert dry well heaters are usually horizontally mounted into the side of a tank. Due to space or access limitations, this style heater can be installed vertically as well. If a vertical installation is likely required, please contact Durex to discuss the specific application and design requirements prior to ordering.

Control and Temperature Sensing Options

Pipe insert dry well heaters are typically remotely controlled by either a thermostat or thermocouple (or RTD) mounted in the tank. However, Durex always recommends the use of a high limit heater element thermocouple to monitor internal temperatures to ensure long heater life and also to provide possible early detection of system upset.

Construction Options

Custom Voltage and Power Rating
A large variety of standard design heaters are available, however, custom volts, watts and watt density are available upon request. For reference, screw plug dry well heaters are typically used up to 5kW or so. A tank needing 15kW, for example, would use three 5kW heaters. Larger power requirements will need flange immersion pipe insert heaters in order to provide the necessary kW.

Mounting Fitting and Configuration
Pipe insert dry well heaters can be designed and manufactured for direct field welding to an existing tank. If a fitting is required for mating to a tank coupling or flange, a screw plug (or flange) can be welded to the dry well pipe to allow for mounting to the tank. The tank mount fitting size is generally (but not always) one size larger than the heater screw plug (or flange) size. For example, a 2" to 2 ½" NPT pipe coupling would be supplied on the dry well. This enables the pipe insert to be screwed into the storage tank coupling and the 2" NPT screw plug heater to be mounted into the dry well pipe assembly.

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Pipe Insert (Dry Well) Vessel Materials
Standard dry well material is carbon steel. However, other materials such as 304SS, 316SS and Inconel® 600 are available.

Pipe Insert (Dry Well) Exterior Treatment and Finish
Passivation and electropolish of the pipe insert external surface can be provided to remove any free iron and also provide a smoother surface finish.

How to Order

To place an order, or get a quotation, please provide the information itemized below. Contact Durex Industries for further assistance.

  • Electrical Rating: Voltage, phase, Wattage
  • Heater Plug or Flange Size: If known or required, the specific heater screw plug or flange size and material
  • Mounting Fitting to Tank: None (for direct-to-tank weld in units), screw plug or flange size and material
  • Dry Well Information: Well dimensional details and/or constraints and material requirements
  • Electrical Enclosure: NEMA 1(standard), NEMA 4, NEMA 7, NEMA 4/7 or CSA Certified.
  • Please designate hazardous location information if a certified enclosure is required
  • Sensing and Control: None (standard) or high limit temperature sensor type

Typical Pipe Insert heating applications


  • Large Storage Tanks
  • Water Tanks
  • Fuel Oil Storage
  • Asphalt & Tar
  • Molasses & Syrup Tanks
  • Chemical Mixers & Reactors
  • Degreasing Tanks
  • Corrosive Liquids Heating
  • Caustic Solutions Heating


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Process Heater Brochure PROC-BROC-0912- 7MB

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