Straight & Formed Tubular Heater Manufacturer
- Manufacturer
- Same Day Manufacturing Available
- CSAus Approved Heaters Available Upon Request (UL Equivalent)
- Always On Time
- Fast, Cheap, and Reliable Shipping
- Quick Response Times (10 minutes or less)
Standard Lead Times
- 3-4 Weeks Manufacturing
- 2 weeks, 1 week, 3-5 day, & 1-2 Day Rush Options Available
- 1-3 days shipping
Send us your drawings or specs to receive a quote!
MPI offers you the absolute best tubular element, available 0.260”, 0.315”, 0.375”, 0.430”, 0.475″ & 0.625″ sheath O.D. Tubular elements are the most versatile, dependable and rugged of any heat generating device. These qualities make it an ideal heat source for many applications. The Tubular Element is the core of the most common heating solutions found today.
MPI Tubular Elements are manufactured from the highest quality materials. This gives you the most dependable heat source for your specific needs.
****Metric Diameters also Available****
Applications
- FORMING MACHINES
- HEATING MOLDS & PLATENS
- IMMERSION INTO LIQUIDS
- RADIANT & CONVECTION HEATING
- EMBEDDED OR CAST INTO METAL
| Overall length (inches) | 11-20 | 21-40 | 41-70 | 71-100 | 101-140 | 141-170 | 171-200 | 201+ |
| Tolerance in sheath length (+/- in) | 0.1 | 0.125 | 0.16 | 0.19 | 0.22 | 0.25 | 0.375 | 0.5 |
| Tolerance in heated length (+/- in) | 0.25 | 0.5 | 0.9 | 1.130 | 1.4 | 1.65 | 2 | 2.38 |
| Min. unheated length (inches) | 1 | 1.25 | 1.5 | 1.625 | 1.75 | 2.25 | 2.25 | 2.5 |
| Tubular diameter (inches) | Maximum voltage | Maximum amps | Minimum Ohms per heated length (inches) | Maximum Ohms per heated length (inches) | Minimum sheath length (inches) | Maximum sheath length (inches) |
| 0.260 | 240 | 15 | 0.1 | 17 | 11 | 240 |
| 0.315 | 300 | 30 | 0.06 | 20 | 11 | 240 |
| 0.375 | 600 | 30 | 0.05 | 20 | 11 | 240 |
| 0.430 | 600 | 40 | 0.05 | 20 | 11 | 240 |
| 0.475 | 600 | 40 | 0.05 | 20 | 11 | 240 |
The two most critical factors that affect the durability of a tubular heater are:
- Sheath material
- Watt density
The corrosivity of the medium and its operating temperature are critical in determining the sheath material type. The table below lists various sheath materials, maximum allowable temperatures and mediums within which they are recommended to operate.
The watt density determines the temperature that a heating element sheath will attain within specific application conditions.
| Sheath Material | Maximum Sheath Temperature | Applications |
| Copper | 350°F | Immersion into water and non-corrosive low viscosity liquids |
| Steel | 750°F | Oil, wax, asphalt, cast in aluminum or iron |
| Stainless Steel 304-316 | 1200°F | Corrosive liquids, food industry, sterilizers |
| Incoloy | 1500°F | Air, corrosive liquids, clamped to surfaces |
THE WATT DENSITY IS DETERMINED WITH THE FOLLOWING FORMULA:
FACTORS TO BE CONSIDERED WHEN SELECTING WATT DENSITIES
- Application temperature
- Application conditions
- The maximum recommended temperature for the selected sheath material (table shown above).
- The maximum watt density recommended for the material being heated. The table below shows some popular materials with their maximum recommended operational temperatures and watt densities.
- In the case of possible scale or sludge formation, heater elements should run at lower watt densities.
- In clamp-on applications, graph 1 (see below) shows the relationship between the watt density of the heating elements, the required operating temperature, and the maximum targeted sheath temperature.
- When heating gases, the speed of the incoming gas and its outlet temperature should be considered in watt density calculations. Graphs 2, 3, 4 and 5 (seen below) show the relationship between the flow rate of air, its outlet temperature, the sheath temperature of the heating element selected and its corresponding watt density.
- When operating in vacuum, the watt density should be 20% to 30% lower. Because of the absence of air, heaters in vacuum mostly conduct heat through radiation.
MAXIMUM WATT DENSITY RATINGS FOR VARIOUS SOLUTIONS
| Solution | Maximum Watts/in2 | Max Operating Temperature (°F) |
| Acetic acid | 40 | 180 |
| Chromic acid | 40 | 180 |
| Citric acid | 23 | 180 |
| Nitric acid | 20-25 | 167 |
| Phosphoric acid | 25-28 | 180 |
| Alkaline solutions | 40 | 212 |
| Asphalt, tar | 4-10 | 200-500 |
| Bunker C fuel oil | 10 | 160 |
| Caustic soda 2% | 45 | 210 |
| Caustic soda 10% | 25 | 210 |
| Caustic soda 75% | 10 | 180 |
| Ethylene glycol | 30 | 300 |
| Fuel oil pre-heating | 9 | 180 |
| Gasoline | 20 | 300 |
| Machine oil, SAE 30 | 18 | 250 |
| Mineral oil | 16-26 | 200-400 |
| Molasses | 4-5 | 100 |
| Heat transfer oils | 12-20 | 500-650 |
| Vegetable oil | 30-50 | 400 |
| Degreasing solution | 23 | 275 |
| Hydraulic oil | 12-15 | 100 |
| Sodium phosphate | 40 | 212 |
| Trichlorethylene | 23 | 150 |
| Clean water | 55-80 | 212 |
| Deionized water | 60 | 212 |
| Demineralized water | 60 | 212 |
MOISTURE RESISTING SEALS
The MgO insulating medium inside a tubular heater is highly hygroscopic and can absorb moisture from its terminal ends. Moisture resisting seals are barriers that resist or stop moisture and contamination.
SILICONE RESIN
This seal is a silicone-based resin that is applied to tubular heater terminal ends. The seal penetrates a short length of the MgO insulation and transforms it into a moisture and contamination resistant medium suitable for temperatures below 390°F.
RTV SEAL
This is a silicone room temperature vulcanizing seal that can resist moisture and contamination for up to 450°F.
EPOXY SEAL
This is a liquid resin which is thermally cured to reach solid state. This moisture barrier is adequate for temperatures up to 250°F.
