Pipe Insert (Dry Well) Heaters
Screw plug and flange immersion heaters can be used to heat a "dry well" in a tank, also referred to as a pipe insert heater. This provides tank heating while facilitating easy removal of the heater without draining the tank contents.
Removal of an immersion heater from a tank for servicing or replacement requires that the tank is drained. When this is impractical, an alternative is to install the immersion heater in a pipe insert or "dry well" arrangement. The immersion heater is fitted with a pressure-tight bayonet pipe or closed end protection tube. This assembly is then mated to a coupling or flanged nozzle connection in the storage tank. This isolates the immersion heater from tank contents thereby facilitating easy heater removal without draining the tank. Low heater element watt densities are used to ensure long heater life.
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Typical Pipe Insert Heater 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
- Low watt density heater elements for reliable performance & long life
- High Alloy Incoloy® 840 heater element sheath prevents premature heater failure
- Standard and hazardous location certified enclosures ensure safe, effective site installation & operation
- ANSI Class 150lb, 300lb, and 600lb rating are available for flexibility to meet your system needs
- Steel, 304SS and 316SS pipe insert (vessel) materials for proper material compatibility with a wide range of fluids
- Welded construction throughout ensures system integrity & pressure-tight performance
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
Dry well heaters are usually horizontally mounted into the side of a tank. Due to space or access limitations, dry well heaters 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.
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
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.
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
Process Heater Brochure PROC-BROC-0912- 7MB