Safe operation of heaters (including explosion proof/hazardous areas) equipped with these enclosures depends on employment of electrical wiring meeting National Electric Code and limiting 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 system malfunction. Common Flanged Immersion Heaters-Nema Enclosure Types–See Below:

• NEMA 1- General purpose, sheet metal, painted with enamel.
• NEMA 4- Moisture Resistant. These enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and windblown dust); to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (rain, sleet, snow, splashing water, and hose directed water); and that will be undamaged by the external formation of ice on the enclosure.
• NEMA 4X- Enclosures are primarily intended for indoor/outdoor use and offer a superior level of protection from corrosion and extreme environments. Provide a degree of protection against windblown dust and rain, splashing water, hose directed water, and damage from external ice formation.
• NEMA 7- Explosion Proof Enclosures are designed to contain an internal explosion without causing an external hazard. These enclosures are intended for indoor use in hazardous locations classified as Class I, Division I, Groups A,B,C, or D.

Grounding Connector Standard - A solid terminal connector is standard on all NPH immersion heaters insuring positive ground and personal safety. Special Flanged Immersion Heaters-Features Available:

Kilowatt Ratings - 500 KW and above available

Flanges:

Materials - 316, 321, 347 stainless steel. Inconel, Incoloy

Ratings - 300 lb. up to 2500 lb., pressure classes available

Sizes - 10" , 12", 14", 16", and 18" available. Please contact NPH for other materials or ratings.

Elements Materials - 316, 321, 347 stainless steel. Inconel. Other materials available, please contact NPH

Other Features - ASME Sections I, IV, and VIII designed and certified. Baffles on elements to distribute flow. Passivation on stainless steel. Immersion lengths up to 240". Underwriters Laboratories U.L./CSA listing available. Consult NPH.

National Plastic Heater Corrosion Policy:

NPH does not warrant any of its flanged immersion heaters against damage from corrosion, contamination, misapplication, improper specification or operating conditions beyond our control. NPH will suggest/recommend sheath materials and watt densities from time to time however, it is the responsibility of the purchaser and his engineer to make the ultimate choice of sheath material based on his knowledge of chemical composition of corrosive solution, character of materials entering the solution, and controls which he maintains on the process. Further, since NPH has no control over the use and sometimes misuse of the heaters, we cannot guarantee against burnouts.