Screw Plug Immersion Heaters

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Screw Plug Immersion Heaters consist of hairpin bent tubular elements brazed or welded into a screw plug and provided with terminal enclosures for electrical connections. Screw Plug Immersion Heaters are screwed directly through a threaded opening in a tank wall or through a matching pipe coupling or half coupling. Sizes of screw plug heaters are available with 1/2, 3/4, 1, 1-1/4, 2 and 2-1/2" pipe threads. A wide selection of screw plug sizes, kilowatt ratings, voltages, sheath materials, terminal enclosures and thermostats makes these compact heaters ideal for all types of applications.

Applications

Screw Plug Immersion Heaters are used for heating liquids and gases in a variety of processes. These heaters are ideal for process water heating and freeze protection. All types of oils and heat transfer solutions can also be heated using these compact, easily controlled units. The direct immersion method is energy efficient and well suited for many applications.

· Hot Water Storage Tanks
· Warming Equipment
· Preheating all Grades of Oil
· Food Processing Equipment
· Cleaning and Rinsing Tanks
· Heat Transfer Systems
· Process Air Equipment
· Boiler Equipment
· Freeze Protection of Any Fluid

Application Guide

Screw Plug Immersion Heaters
Guides, Specification Sheets and General Information
Application	Screw Plug Size (in. )	Sheath Material	Screw Plug Material	Heater Model	Integral Thermostat

Water Oil	2-1/2 2-1/2	Incology Incology	Steel Steel	versaTHERM versaTHERM	thermocouple thermocouple
Any	2.5	any	any	intelliTHERM	thermocouple
Clean Water	1 1 1-1/4 1-1/4 2 2 2 2 2-1/2 2-1/2	Copper Copper Copper Copper Copper Copper Copper Incoloy Copper Copper	Brass Brass Brass Brass Brass Brass Brass Brass Brass Brass	ARTM MT ARMT-1 MT-1 EMT-3 ARMT-2 MT-2 CH-SD ARMT-3 MT-3	Yes No Yes No No Yes No No Yes No
Process Water	1 1 1-1/4 1-1/4 2 2 2 2 2-1/2 2-1/2	SS SS SS SS SS SS SS SS SS SS	SS SS SS SS SS SS SS SS SS SS	MTS ARTMS ARMTS-1 MTS-1 ARMTS-2 MTS-2 AREMTS-3 EMTS-3 ARMTS-3 MTS-3	No Yes Yes No Yes No Yes No Yes No
Solution Water	2 2 2 2 2-1/2 2-1/2	Incoloy Incoloy Incoloy Incoloy Incoloy Incoloy	SS SS SS SS SS SS	ARMTI-2 MTI-2 AREMTI-3 EMTI-3 ARMTI-3 MTI-3	Yes No Yes No Yes No
Corrosive Solutions	2 2 2 2	SS SS Incoloy Incoloy	SS SS SS SS	AREMTS-3 EMTS-3 AREMTI-3 EMTI-3	Yes No Yes No
Application	Screw Plug Size (in. )	Sheath Material	Screw Plug Material	Heater Model	Integral Thermostat

Severly Corrosive Solutions	2 2 2 2	SS SS Incology Incology	SS SS SS SS	AREMTS-3 EMTS-3 AREMTI-3 EMTI-3	Yes No Yes No
Light Weight Oil	1-1/4 1 1-1/4 1-1/4 2 2 2 2 2-1/2 2-1/2	Steel " " " " " " " " "	Steel " " " " " " " " "	ARTMO-1 MTO ARMTO-1 MTO-1 ARMTO-2 MTO-2 AREMTO-3 EMTO-3 ARMTO-3 MTO-3	Yes No Yes No Yes No Yes No Yes No
Medium Weight Oil	2 2 2 2 2-1/2 2-1/2	Steel " " " " "	Steel " " " " "	ARMTO-2 MTO-2 AREMTO-3 EMTO-3 ARMTO-3 MTO-3	Yes No Yes No Yes No
Heavy Weight Oil	2 2 2 2 2-1/2 2-1/2	Steel " " " " "	Steel " " " " "	ARMTO-2 MTO-2 AREMTO-3 EMTO-3 ARMTO-3 MTO-3	Yes No Yes No Yes No
Specialty Heaters- Water, Oil & Corrosive Fluids	1 1 1 1-1/4 2 2	Incoloy SS Incoloy SS SS Incoloy SS Incoloy SS Copper SS Steel Copper Incoloy Incoloy	Steel Steel Brass Brass SS Steel Steel Brass Brass Brass SS Steel Brass Brass Steel	RI RIO RIN RINO RIS RI RIO RIN RINO TMW-1 TMWS-1 TMO-1 TMW-2 DWH MTO-LT	No No No No No No No No No No No No No Yes No

Technical & Application Data

Description
Heavy duty tubular elements are welded or brazed to a screw plug. Uniform heat distribution and repressed element bendslead to long element life. For all heaters, a thermowell (hollow tube sealed at one end) is welded or brazed to the screw plug allowing thermostat sensing element replacement without draining the tank. A variety of methods of terminating power leads is available for special application heaters.

General purpose screw plug heaters are equipped with a steel terminal enclosure painted with red enamel. These same heaters are also available with a combination moisture tight/explosion resistant terminal enclosure that may be used in applications where either or both conditions exist. Screw plug type heaters are screwed directly through a threaded opening in the tank wall. Heavy tank walls may be drilled and tapped if thickness is sufficient to engage 3/4 of the threads. Lighter tank walls should be equipped with a suitable pipe half-coupling welded or brazed to the tank wall.

Construction Features - Stock & Assembly Stock Units

Element
Materials -- copper, steel, INCOLOY ® , 304 stainless steel
Number Elements in Screw Plug -- 1, 2 or 3 depending on screw plug size.
Element Diameter -- 0.315, 0.375, 0.430 and 0.475".
Watt Density -- 6.5, 15, 23, 45 and 75 W/In 2.

Screw Plug
Materials -- carbon steel, brass, 304 stainless steel.
Size -- 1/2, 3/4, 1, 1-1/4, 2, 2-1/2" NPT nominal.
Tolerances -- Tolerance on immersion length (B) dimension is ± 1% ( ± 3/8" min.).

Terminal Enclosures

Type E1 General purpose, sheet metal, painted with red enamel. The terminal enclosure rotates 360 ° to accommodate an electrical conduit run.

Type E4 Moisture resistant housing.

Type E2 Combination moisture resistant/ explosion resistant.

Type E2 explosion resistant enclosures are for use in hazardous location conditions:
• Class I Groups B, C & D, Division 1 & 2
• Class II, Groups E, F & G, Division 1 & 2
• Class III, Division 1 & 2.

Safe operation of heaters equipped with explosion resistant enclosures depends on electrical wiring meeting the National Electrical

Code for hazardous locations and on limiting the maximum operating temperatures (including temperatures on outside of vessel,

piping, flanges, screw plugs, enclosures and other heat conducting parts) as dictated by flammable liquids, vapors or gases present. Approved pressure and/or temperature limiting controls must be used to assure safe operation in the event of a system malfunction.

Temperature Controls

Many screw plug type heaters are available with built-in thermostatic controls. In some installations where there is more than one heater in a tank, one heater with a built-in control can be used to control the other heaters by wiring the thermostat into the holding coil circuit of a magnetic contactor. If the thermostat is separate from the heater, the thermostat sensing element should be located in the liquid approximately 4 to 6 inches above the heater.

1 and 1-1/4" Screw Plugs -- Type ARTM, ARTMO and ARTMS. The ARTM, ARTMO or ARTMS automatic thermostat has a temperature range of 60 ° F - 187 ° F (T4). Also available with alternate temperature 60 ° F -240 ° F (T5) or 0 ° F - 127 ° F (T8). The tamper resistant temperature adjustment screw and scale are inside requiring the removal of the cover to change temperature setting.

2 and 2-1/2" Screw Plugs -- Type ARMT, ARMTI, AREMTI, ARMTS, AREMTS, AREMTO and ARMTO. The integral thermostat is available with temperature ranges at 60 ° F - 250 ° F (T2) or 0 ° F - 100 ° F (T1) for ARMT, ARMTI, AREMTI, AREMTS and ARMTS heaters. ARMTO and AREMTO heaters are available with three different temperature ranges: 200 ° F - 550 ° F (T3), 60 ° F - 250 ° F (T2) and 0 ° F - 100 ° F (T1). This control is wired in as a line thermostat for loads up to 3 kW on 120 volts and up to 6 kW on 240 volts. For higher wattage ratings, three phase operation and above 240 volts, this control is used for pilot duty only and should be wired to operate the holding coil of a magnetic contactor. To set the control temperature of heaters equipped with the standard general purpose enclosure (Type E1), adjust the knob on the outside of the terminal enclosure. For those heaters equipped with a Type E2 and E4 enclosure, remove the terminal enclosure lid to expose the temperature adjusting knob. For safety reasons, power to heater and pilot duty power must be turned off before removing enclosure lid.

Note -- The integral thermostat functions as a temperature control only. This is not a fail safe device, so an approved pressure and/or temperature limit control should be used with these heaters to assure safe operation.

CAUTION -- Explosion Resistant Type E2 construction refers to heater design features which provide explosion resistant containment of electrical wiring according to National Electrical Code. Application or use of heaters which result in abnormal or excessive temperature can create hazardous conditions which can lead to a fire or explosive condition.

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