Over The Side Immersion Heaters

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Electric over the side immersion heaters are constructed of multiple hairpin bent tubular heating elements brazed or welded into a terminal housing. The immersion heating elements are inserted into the fluid from the top of tank or through an access port such as a manhole for direct heating of liquids.

Durex Industries designs and manufactures custom over the side immersion heaters that meet your unique specifications. With over 40 years of experience, we manufacture industrial over the side immersion heaters to meet all of your thermal heating applications.

Applications of Industrial Over the Side Immersion Heaters

Industrial over the side immersion heaters provide a reliable heat source for a large variety of tanks when inserting immersion heaters from the side of a tank is not an option due to space limitations. Typical heating mediums include solvents, corrosive chemicals, clean water, process water, lube and fuel oils, caustic solutions, molten salts, as well as wax and viscous liquids.

Over the side immersion heaters, also known as tank heaters or top-mount immersion heaters, provide heating solutions for:

Design Features of Over the Side Tank Heaters

Contact Durex Industries for Over the Side Immersion Heaters

Durex Industries engineers and manufactures custom designs to suit your requirements, as well as providing industry standard over the side immersion heaters in various sizes, material options, and power ratings for your industrial or process heating application.

Our engineers can assist you in providing the best and most efficient heating solution required for your application requirements. Contact us today!

Over The Side Immersion Heater Specifications and Options

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Thermostat Options

----SPST-DPST-Thermostats.jpgThermostats can be mounted inside of the terminal enclosure to provide an inexpensive, local temperature control of the heater and liquid being heated. Process (automatic control) and high limit (manual reset) thermostats are available. Temperature settings are adjustable unless a fixed set point thermostat is ordered.  Single pole (SPST) thermostats are typically used for single phase heaters and double pole (DPST) thermostats for three phase heaters.  For high current draw heaters, the thermostats are often wired for "pilot duty" to a user-supplied relay.

When ordering, please specify temperature range, the number of poles, the type of thermostat (process, manual reset or high limit), and if it will be used directly or wired for pilot duty.

Standard available bulb & capillary thermostats

Temperature Range Type Maximum Amps to 240VAC Maximum Amps to 480V
0 - 100°F Single Pole (SPST) 25 Amps N/A
85 - 230°F Single Pole (SPST) 25 Amps N/A
120 - 570°F Single Pole (SPST) 25 Amps N/A
0 - 100°F Double Pole (DPST) 30 Amps 21 Amps
60 - 250°F Double Pole (DPST) 30 Amps 21 Amps
100 - 250°F Double Pole (DPST) 30 Amps 21 Amps

Temperature Sensor Options

A process thermocouple or RTD probe can be inserted into a thermowell to measure process fluid temperature and provide control input to an external controller.  Type J and Type K thermocouples are the most common calibrations, but RTDs and other calibrations are available.  A high limit thermocouple can be welded or clamped to a heater element to measure element temperature in order to prevent overheat conditions.

Construction Options

Voltage and Wattage - Standard design units are shown on the Standard Heaters tab.  However, volts, watts, and watt density can be modified to suit application requirements.  Contact Durex for more information.

Sheath Material - Steel, 304SS and Incoloy® 840 are standard materials, but others such as Incoloy® 800, 316SS, 321SS, etc. are available as well.

Riser - Standard design heaters use a junction box and riser pipe assembly.  This can be varied to suit application needs.  Also, depending on configuration, the riser assembly can be eliminated and the heater elements (with a long cold riser section) terminated in the enclosure or in a mounting flange.

Mounting Flange and Manhole Cover - For a more permanent tank installation, heaters can be fabricated with a mounting flange or manhole cover plate in order to be seated and secured to the tank.  Contact Durex for more information.

Sludge Legs - Four-inch high sludge legs are standard on heaters unless otherwise specified.  Sludge legs are not required if the heater will be mounted onto the tank with a mounting clip or flange that ensures that the heater elements remain at least 4" off the tank bottom.

Sheath Treatment and Finish - Passivation and electropolish if wetted parts can be provided to remove any free iron and also provide a smoother surface finish.  Contact Durex for more information.

Seal Options - Standard design heaters us an epoxy seal for moisture protection.  RTV is an optional seal if this is preferred to an epoxy seal.

How to Order

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

  • Heater Type - Type 'LN' (L-shaped) or Type 'ON' (O-shaped) or another custom configuration.
  • Electrical Rating - Voltage, phase, wattage.
  • Element Sheath and Riser Material - Steel, 304SS, Incoloy® 840 or other material.
  • Element Watt Density - 8, 16, 23, or 48 W/in² or other value.
  • Riser Height - Provide the distance from bottom of the heater bundle or junction box to the enclosure.
  • Immersion Bundle Length - Provide desired (or maximum allowable) length.
  • Seal Options - Epoxy is standard, specify RTV or other if required.
  • Electrical Enclosure - NEMA 4 is standard.  NEMA 7 and 4/7 are available as well as hazardous location certified enclosures.
  • Mounting Clip or Flange - Indicate clip or flange location on riser relative to the heater bundle and provide clip or flange specifications.
  • Sensing and Control - None (standard), thermostat type (process or high limit manual reset) and range; process sensor type and/or high limit sensor type.

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Factors to Consider When Selecting an Over the Side Immersion Heater

  • Hazardous location installation
  • Voltage rating, phase and kW power rating
  • Available Amps at site of installation
  • Time required to reach desirable temperature setting
  • Temperature control and sensing scheme
  • Quantity of liquid or gas being heated and if flowing or mixing
  • Viscosity and thermal conductivity of the fluid
  • Corrosive nature of the fluid
  • Tank or heating vessel insulation thickness and type
  • Space limitations for installation or heater removal
  • Outdoor or indoor installation
  • Ambient environment operating conditions

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Over The Side Immersion Heater Designs

Standard L-Shaped Styles

Sheathed Elements KW Volts
3-Phase
'A' Vertical Height
to Enclosure
'B' Immersion
Bundle Length
L-Shaped (LN Style) Part Number
Incoloy® 840
3 Elements
NEMA 4 Enclosure
No Thermostat
3 240 39.312" 14.625" MTL4A-39E14KW-30005
480 MTL4A-39E14KW-30008
6 240 39.312" 22.625" MTL4A-39E22KW-60005
480 MTL4A-39E22KW-60008
9 240 39.312" 30.125" MTL4A-39E30BW-90005
480 MTL4A-39E30BW-90006
12 240 51.312" 37.625" MTL4A-51E37KW-120C5
480 MTL4A-51E37KW-120C8
15 240 51.312" 45.125" MTL4A-51E45BW-150C5
480 MTL4A-51E45BW-150C8
18 240 51.312" 52.625" MTL4A-51E52KW-180C5
480 MTL4A-51E52KW-180C8
Sheathed Elements KW Volts
3-Phase
'A' Vertical Height
to Enclosure
'B' Immersion
Bundle Length
L-Shaped (LN Style) Part Number
Steel
3 Elements
NEMA 4 Enclosure
No Thermostat
3 240 39.312" 22.625" MTLBA-39E22KW-30005
480 MTLBA-39E22KW-30008
4.5 240 39.312" 30.125" MTLBA-39E30BW-45005
480 MTLBA-39E30BW-45008
6 240 39.312" 37.625" MTLBA-39E37KW-60005
480 MTLBA-39E37KW-60008
7.5 240 51.312" 45.125" MTLBA-51E45BW-75005
480 MTLBA-51E45BW-75008
9 240 51.312" 52.625" MTLBA-51E52KW-90005
480 MTLBA-51E52KW-90008
Sheathed Elements KW Volts
3-Phase
'A' Vertical Height
to Enclosure
'B' Immersion
Bundle Length
L-Shaped (LN Style) Part Number
304 Stainless Steel
3 Elements
NEMA 4 Enclosure
No Thermostat
3 240 39.312" 14.625" MTLRA-39E14KW-30005
480 MTLRA-39E14KW-30008
6 240 39.312" 22.625" MTLRA-39E22KW-60005
480 MTLRA-39E22KW-60008
9 240 39.312" 30.125" MTLRA-39E30BW-90005
480 MTLRA-39E30BW-90008
12 240 51.312" 37.625" MTLRA-51E37KW-120C5
480 MTLRA-51E37KW-120C8
15 240 51.312" 45.125" MTLRA-51E45BW-150C5
480 MTLRA-51E45BW-150C8
18 240 51.312" 52.625" MTLRA-51E52KW-180C5
480 MTLRA-51E52KW-180C8

 

Standard O-Shaped Styles

Sheathed Material KW Volts
3-Phase
'A' Vertical Height
to Enclosure
'B' Immersion
Bundle Length
O-Shaped (ON Style) Part Number
Incoloy® 840
3 Elements
NEMA 4 Enclosure
No Thermostat
3 240 39.312" 10.75" MTO4A-39E10MW-30005
480 MTO4A-39E10MW-30008
6 240 39.312" 13.5" MT04A-39E13HW-60005
480 MT04A-39E13HW-60008
9 240 39.312" 16" MT04A-39E160W-90005
480 MT04A-39E160W-90008
12 240 51.312" 18.5" MT04A-51E18HW-120C5
480 MT04A-51E18HW-120C8
15 240 51.312" 21.25" MT04A-51E21DW-150C5
480 MT04A-51E21DW-150C8
18 240 51.312" 23.5" MT04A-51E23HW-180C5
480 MT04A-51E23HW-180C8
Sheathed Elements KW Volts
3-Phase
'A' Vertical Height
to Enclosure
'B' Immersion
Bundle Length
O-Shaped (ON Style) Part Numbers
Steel
3 Elements
NEMA 4 Enclosure
No Thermostat
3 240 39.312" 13.5" MTOBA-39E13HW-30005
480 MTOBA-39E13HW-30008
4.5 240 39.312" 16" MTOBA-39E160W-45005
480 MTOBA-39E160W-45008
6 240 39.312" 18.5" MTOBA-39E18HW-60005
480 MTOBA-39E18HW-60008
7.5 240 51.312" 21.25" MTOBA-51E21DW-75005
480 MTOBA-51E21DW-75008
9 240 51.312" 23.5" MTOBA-51E23HW-90005
480 MTOBA-51E23HW-90008
Sheathed Elements KW Volts
3-Phase
'A' Vertical Height
to Enclosure
'B' Immersion
Bundle Length
O-Shaped (ON Style) Part Numbers
304 Stainless Steel
3 Elements
NEMA 4 Enclosure
No Thermostat
3 240 39.312" 10.75" MTORA-39E10MW-30005
480 MTORA-39E10MW-30008
6 240 39.312" 13.5" MTORA-39E13HW-60005
480 MTORA-39E13HW-60008
9 240 39.312" 16" MTORA-39E160W-90005
480 MTORA-39E160W-90008
12 240 51.312" 18.5" MTORA-51E18HW-120C5
480 MTORA-51E18HW-120C8
15 240 51.312" 21.25" MTORA-51E21DW-150C5
480 MTORA-51E21DW-150C8
18 240 51.312" 23.5" MTORA-51E23HW-180C5
480 MTORA-51E23HW-180C8

Typical Over The Side Immersion Heater Applications

  • Storage tanks
  • In-ground tanks
  • Solvent tanks
  • Molten salts heating
  • Caustic solutions heating
  • Wax & viscous liquids
  • Rinse tanks & parts cleaning
  • Wash basins
  • Lube & fuel oil heating
  • Freeze protection & winterizing

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Process Heater Brochure PROC-BROC-0912- 7MB


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