Circulation Heaters | Re-Circulation Heaters
Circulation Heaters | Re-Circulation Heaters
Circulation Heaters | Re-Circulation Heaters

Industrial Process

Industrial Process Electric Heaters - Products Flanged Immersion Heaters Screw-Plug Heaters Duct Heaters Circulation Heaters Over-the-Side Heaters Finned Tubular Heaters Pipe Insert Heaters Tubular Heaters and Elements Temperature/Power Control Panels
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Circulation, Re-Circulation Heaters:

Circulation heaters Circulation heaters
Circulation, Re-Circulation Heaters


NPH circulation heaters feature all-welded construction of the steel shroud and flanges, hydrostatically pressure-tested ports, heavy-duty metal-sheathed heating elements of Incoloy or steel, galvanized or carbon steel containment pipe, NEMA1 terminal housings, bulb & capillary thermostats or solid-state controls, plus up to a 150-lb. forged steel flange with bolt construction connecting the terminal housing and containment vessel.

Circulation or Recirculation Heaters Specifications

Circulation Heaters Recirculation Heaters Wiring Diagrams

How to Extend the Life of Your Circulation Heater

Circulation Heaters Features:

Circulation Heaters | Re-Circulation Heaters High efficiency heat transfer

Pressure ratings to 600 lbs

ANSI Standard NPT or ANSI Class 150 connections

Heaters could be screw plug or flanged

Circulation Heaters | Re-Circulation Heaters Stainless steel construction with Canadian Vessel Registration

Various housing options available NEMA 4, 4X, explosion proof

Suitable for steam, oils, chemicals, gases, corrosive solutions

Optional Features

Weather Proof Insulated Shroud

All Stainless Steel Construction

ASME Section 8 Construction on Vessel

High Pressure Construction

High Temperature Ceramic Fiber Insulation

Passivation on all Wetted Surfaces

Other Sheath Materials: Carpenter 20, Model 400, Inconel 600, Hastelloy, and Titanium

Applications Factors
Heater selection is influenced by the following parameters:

Circulation Heaters | Re-Circulation Heaters The Heated Medium, Viscosity, Specific Heat, Density and Corrosive Properties

The Presence of Contaminants in the Medium

The Corrosion Resistant Properties of the Heated Medium

The Sheath Watt Density of the Heating Elements (the watts/in²) and the Flow Rate of the
     heated moedium

The Vessel Design and Materials of Construction

Times, Temperature, and Pressure

Pressure Vessels

All standard pressure vessel (tank) materials are rated to 150 lb. and made from:

Carbon Steel

304/316 Stainless Steel

All catalog pressure vessels (tank) are steel unless otherwise noted.


Sheath Material                        Application                           Watt Density



Copper                                     Potable water                               40-80


Steel                                Fuel Oils, Hydraulic Oils                  20-25 &12-25


Stainless                       De-Ionized, R-O, Process Water              40-80

Steel                                           Mild Acids                                    12-25


Incoloy 800                Water, Mild Alkaline Solutions, Air               10-125

                                     and Gases, Maximum Sheath

                                           Temperature 1400ΊF


Inconel 600                   Water, Very Alkaline Solutions,                 10-50

                                   High Temperature Air And Gases

                                     Maximum Sheath Temperature



Titanium                            Sea Water, Very Alkaline                        10-45

                                     Solutions, Some Acid Solutions  

Circulation Heaters Specifications / Design Capabilities:

Voltages. . . . . . . . . . . . . . . .120 to 600 Volts

Inlet/outlet. . . . . . . . . . . . . .N PT 1 /2" to 21 /2

Flanges 2" to 14" 16" to 24" on request

Heater. . . . . . . . . . . . . . . . .NPT or flange mount as required

Wattage's. . . . . . . . . . . . . . .Varied from 150 watts to 1 Megawatt

Sheath Materials. . . . . . . . . . Titanium, Monel, Incoloy, 316/304 Stainless,

Steel Copper, Carbon Steel

Max Temperatures. . . . . . . . . Incoloy 1600 degrees F (870 C)

304 / 316 Stainless Steel 1200 degrees F (650)

Steel 750 degrees F (400 C)Copper 350 degree F (175 C)

Pressure Rating. . . . . . . . . . . 150, 300 or 600 Ibs

Flange Materials. . . . . . . . . . .Standard Carbon Steel or 316/304 Stainless

Gaskets. . . . . . . . . . . . . . . . Rubber, Asbestos Free, or Spiral wound

Terminal Enclosures. . . . . . . . General Purpose (NEMA 1 ),

Moisture Resistant (NEMA 4), Corrosion

Resistant (NEMA 4X), Explosion Resistant (NEMA 7),

Explosion Moisture Resistant (NEMA 7/4)

Temperature control. . . . . . . .Thermocouple, RTD, or Thermostat

High Limit. . . . . . . . . . . . . . . High Limit Thermocouple, Hi Limit Tstat,

Certification. . . . . . . . . . . . . ASME, CRR, Heater & Vessel certification

How To Order Circulation, Recirculation or Closed Loop Industrial Heaters

Quotation Request Form
(Please complete the fields below)
Specify vessel materials
Specify operating pressure
Specify inlet and outlet
Specify British Thread
Specify plug materials
Specify ANSI Flange size
Specify ANSI Flange rating
Specify ANSI Flange Material
Non ANSI Flanges available in a variety of sizes and materials
Specify sheath materials
Specify power ratings
Specify temperature range of thermostats
Specify temperature sensor options
First Name Last Name
Company Name Position
Address City/State/Province
Zip/Postal Code Country
Phone Number Fax Number
Toll Free Number Email
Web Site OEM Distributor Process User
Quotation Request Required Delivery Date
have a salesperson contact me


Telephone: 905-859-8225        Facsimile: 905-859-4691

Toll Free: 1-877-674-9744

Our industrial process electric heaters...

Our industrial process electric heaters consist of the following product categories: flanged immersion heaters, screw-plug immersion heaters, over-the-side heaters, circulation heaters, duct or air process heaters, pipe insert heaters, tubular heaters , finned tubular heaters and Temperature Control Power Panels.

Industrial process heaters are available with adjustable thermostats, digital temperature controls; SCR, mercury relay or mechanical temperature control power panels with process and high limit thermocouples.

Industrial process heaters from National Plastic Heater, Sensor and Control Inc. are Hydro approved and CSA or C UL recognized. Terminal enclosures can be NEMA 1 (General Purpose), NEMA 4, ( Moisture resistant) NEMA 4X (Corrosion/Moisture Resistant), NEMA 7 (explosion proof) and NEMA 12 (Dust and Oil Resistant).

Industrial heater sheath materials like Titanium, Incoloy, Stainless Steel, Steel, and Copper can be used as required for specific applications. Standard Flanged Immersion Heaters have a 150 lbs flanges but 300, 600 and 1500 lbs flanges are also available.

Below a brief description of most of our industrial process heaters line-up:

Screw plug immersion heaters consist of hairpin bent tubular elements brazed or welded into a screw plug and provided with terminal boxes for electrical connections.

Screw plug immersion heaters are screwed directly through a threaded opening in a tank wall or through matching pipe coupling, half coupling or welding flange.

Circulation Heaters offer the following: High efficiency heat transfer, Pressure ratings to 600 lbs, ANSI Standard NPT or ANSI Class 150 connections, Heaters could be screw plug or flanged, Stainless steel construction with Canadian Vessel Registration, Various housing options available NEMA 4, 4X, explosion proof,

Suitable for steam, oils, chemicals, gases, corrosive solutions.

Heating using pipe insert heaters: A pipe insert heater uses an element inserted into a sealed pipe. The advantage to the pipe insert heater is that the element is isolated from the process. This allows the element to be removed without draining the tank, isolates hazardous or corrosive materials from deteriorating the element, and if sized properly may allow the heat to be distributed over a larger surface area reducing the watt density exposed to the process.

Over-the-side immersion heaters are designed for vessels where through the side immersion heaters cannot be conveniently installed. These heaters are installed through the top of the vessel with the heated portion of the unit along the side or at the bottom of the tank.

NPH Tubular heaters can be used in their straight form or bent into various shapes.

Tubular heaters can be used in free air, clamped to a surface, placed inside a groove or cast into metal.

Finned tubular heaters offer distinct advantages over open coil heaters: (a) they are safer to operate in that the risk of fire or electrical shock are minimized; (b) they have a much longer service life; and (c) they are more rugged requiring less maintenance than open coil heaters.

Duct heaters from National Plastic Heater are composed of, tubular, finned tubular or open coil heating elements that are either flanged or inserted in the duct. Duct air heaters are generally an assembly of tubular heating elements ready to mount into a duct but it can also be an open-coil resistance wire assembly mounted into a duct.

Temperature Control Power Panels, for a wide variety of applications are designed and engineered by National Plastic Heater, Sensor and Control Inc. Entire systems are available for the most complex process heating control applications that require electric heaters, temperature controls, and temperature sensors. Control power panels can be built with as little as one zone to as many as 36 or even more temperature control sensing points.