Operating 26mm Cartridge Heaters in Harsh Environments

A food packaging plant is open all day and all night. Every day, high-pressure hoses wipe down the packaging machinery. The air is humid. Cartridge heaters work within these machines under conditions that would damage regular electronics. For a 26mm big diameter single head electric heating tube, tough situations need unique design features to keep it from breaking down too soon. Knowing these things can save you thousands of dollars in replacement expenses and unexpected downtime.


Moisture is the biggest problem for cartridge heaters in factories. The magnesium oxide insulation in a single-head electric heating tube absorbs a lot of moisture. When the heater is in a humid place, moisture slowly seeps through tiny holes at the end of the heater. When the heater is on, this moisture turns into steam, which builds up pressure inside the heater and can break the MgO or cause an electrical short. A 26mm big diameter single head electric heating tube has a greater internal volume, which means it can hold more MgO before it fails. However, if moisture keeps getting in, it will eventually fail.

For places that are moist or humid, hermetically sealed termination ends are the best choice. A sealed 26mm cartridge heater has either an epoxy seal that can handle temperatures up to 200°C or a ceramic seal that can handle even greater temperatures. The seal keeps moisture out of the heater, even when it is cold and the pressure within is lower than the pressure outside. When you order a cartridge heater for a washdown area, make sure to ask for seals that can withstand moisture. Some companies also sell Teflon lead wires that are better at keeping moisture and chemicals out than regular fiberglass-insulated leads.

Another problem is chemicals that eat away at things. The cartridge heater sheath may come into contact with acids, alkalis, or salt solutions in plating lines, chemical processing equipment, and some food processing applications. Chlorides and strong acids will quickly damage standard 304 stainless steel sheaths. A 26mm big diameter single head electric heating tube with an Incoloy 825 or titanium sheath is better at resisting corrosion in these settings. These materials are more expensive than 304 stainless steel, but the longer they last in corrosive situations makes the extra cost worth it.

Lead wire materials need extra care in settings with high temperatures over 500°C. Standard fiberglass-insulated leads start to break down when the temperature goes above 250°C. When a 26mm big diameter single head electric heating tube is used in a die casting mould or glass processing equipment, the temperature near the lead exit point can be over 400°C. In these situations, you need high-temperature leads with ceramic fibre insulation and conductors made of nickel-plated copper or pure nickel. Some uses need armoured leads with a metal overbraid to prevent against wear and tear from moving parts.

People generally don't think about vibration and mechanical shock as environmental elements. Continuous vibration in extrusion lines or injection moulding machines with hydraulic systems might cause the internal resistance wire of a cartridge heater to fail due to fatigue. The thicker sheath and bigger interior parts of the 26mm single head electric heating tube make it naturally better at resisting vibration than smaller tubes. However, for applications with a lot of vibration, choosing a heater with a swaged construction-where the MgO is compacted into a solid mass that holds the resistance wire-makes it even more durable.

What about places where there are explosions or fires? Any electrical heating device used in paint booths, chemical industries, or grain handling facilities must fulfil high safety criteria. These places need an explosion-proof certificate for a 26mm big diameter single head electric heating tube. This certification requires a strong sheath design that can hold up to an internal failure without setting off the surrounding atmosphere. Cartridge heaters that are explosion-proof also have sealed termination boxes that stop flames from spreading.

Installation methods for hostile conditions are also different from those for normal use. To keep water from pooling around the leads in washdown situations, the heater bore should be pointed down or to the side instead of up. After installation, a small amount of silicone sealant around the lead exit point makes it much harder for moisture to get in. To stop galvanic corrosion between the heater sheath and the bore wall in corrosive situations, the mould or equipment itself should be composed of materials that work well together. Every industry, from food processing to chemical production to maritime applications, has its own set of problems that need particular cartridge heater requirements.