Review & Buy Split Sheath Cartridge Heaters
Common Issues with Standard Cartridge Heaters:
Lubricantslike graphite or silicone facilitate the insertion of the cartridge heater but can carbonize at higher temperature and then the heater will be really stuck.
For process temperatures above 450 deg F, use high- temp lead wire and ceramic bead insulation. Or order the heater with an additional length of cold section.
The location of the temperature sensor is very critical. If the sensor is too far from the heater, then the surrounding area's ability to dissipate the heat generated by the heater may be exceeded.
The NPHsplit sheath cartridge heateris designed especially for platen, die or mold industrial heating applications where the holes are poorly drilled or worn through age. Independent expansion of each section of the split sheath cartridge heater when energized, creates intimate contact with the wall of the hole.
Through the patented split-sheath design and highly specialized manufacturing techniques, NPH split sheath insertion heatersreduce your total cost of process heating by an average of 40% over other heaters.
NPH's split sheath cartridge heaters use a unique, patented split-sheath design that expand when energized to maximize heat transfer through greater contact with the wall of the bore.Better heat transfermeansless poweris consumed to maintain the set point temperature, reducing operating costs.
This heater construction eliminates ceramic cores typically found in conventional cartridge heaters. NPH has developed and highly-specialized manufacturing techniques to compacthigh-grade MgO dielectricto its near theoretical maximum around the heater coil, which increases dielectric strength and heat transfer away from the coil which results insignificantly longer heater life.
Split sheath cartridge heaterslast up to 5 times longerthan conventional heaters withless downtimefor heater replacements andlower maintenancecosts. NPH split sheath cartridge heaters contract when de-energized, eliminating bore seizure and the need for expensive drill-outs.
Expanding Split Sheath Cartridge Heater Showing Resistance Wire for Hot And Cool Tip Construction Options
Bore Hole Graphic Comparing Expanding Split Sheath Cartridge Heater Vs Standard Cartridge Heaters In Hole Advantage
Maximize Heat Transfer
Expanding Split Sheath Cartidge Heater with Cool Tip and Optional In Split Sheath or On Sheath Type K TC, FG Leads
NPH Expanding Split Sheath Cartridge Heater with Hot or Cool Tip, Optional External In Split Sheath or On Sheath Type K TC
NPH Expanding Split Sheath Cartridge Heater with Post Terminals
NPH Expanding Split Sheath Cartridge Heater with S.Steel NPT Fitting, 3 in. FG Leads with Optional Ring Terminals
NPH Split Sheath Cartridge Heater with Mounting Flange with 3 in. FG Leads & Optional Ring Terminals
Conventional Cartridge: is limited to ordinary thermal expansion, cannot compensate for oversized bores.
NPH Split Sheath Energized Heater: The unique bi-lateral expansion of an energized NPH split sheath cartridge heater produces superior metal-to-metal contact with the surrounding bore, thereby maximizing heat transfer.
NPH Cartridge Heater De-Energized: When de-energized, the NPH split sheath cartridge heater contracts for easy removal from bore.
- How much wattage is required?
- What voltage will be used?
- What is the heated length? What is the overall length?
- How long are the heater leads or what is the lead length required?
- What is the dimentions of the cartridge heater?
- What is the ambient temperature the cartridge heater will see?
- What is the maximum temperature required from the heater?
- How quickly do you want to reach your operating temperature or set point in hour/minutes?
- What is the type and weight (in lbs.) of the material you want to heat?
- Special Modifications
Frequently Asked Questions About Standard-Size Split Sheath Cartridge Heaters
What standard sizes are available for split sheath cartridge heaters?
NPH standard-size split sheath cartridge heaters are available in 1/4", 3/8", 1/2", 5/8", 11/16", 3/4" and 1" diameters, as well as 8, 10, 12, 12.5, 15, 16 and 20 mm metric diameters. Available lengths vary by diameter and generally range from approximately 1-1/4" to 90". Review our standard and metric cartridge heater sizes for additional imperial, metric and custom options. For smaller diameters, see our miniature split sheath cartridge heaters.
How does an expandable split sheath cartridge heater work?
An expandable split sheath cartridge heater consists of two independently expanding sheath sections. When the heater is energized, the two sections expand outward against the bore wall, improving metal-to-metal contact and heat transfer. When power is removed, the sheath sections contract independently, simplifying insertion, removal and replacement. See the NPH split sheath cartridge heater brochure for construction details and dimensional information.
What is the difference between a split sheath heater and a conventional cartridge heater?
A conventional cartridge heater depends mainly on normal thermal expansion and a closely machined bore for efficient heat transfer. A split sheath heater expands bilaterally against the surrounding bore, helping reduce air gaps in worn, oversized or imperfectly drilled holes. This can provide more uniform heat transfer, lower internal heater temperatures and easier removal. Learn more about standard and conventional cartridge heaters to compare the available constructions.
What bore clearance is recommended for a split sheath cartridge heater?
For most standard-size NPH split sheath cartridge heaters, the difference between the heater outside diameter and bore inside diameter should generally be approximately 0.005" to 0.007". Smaller-diameter heaters may benefit from a slightly tighter fit. The bore should also be clean, smooth, straight and free from oil, moisture, plastic residue and other contamination. Review the cartridge heater installation and preventive maintenance guide before installation.
How do I select the correct wattage and watt density?
Correct wattage and watt density depend on the heater diameter, heated length, bore fit, material being heated, operating temperature, heat losses, required heat-up time and available voltage. Selecting more wattage than the application requires can increase heater temperature and shorten service life. Use the cartridge heater watt-density and heat-calculation guide or consult NPH for an application review.
Can standard-size split sheath cartridge heaters be customized?
Yes. Standard-size expandable sheath cartridge heaters can be manufactured with custom lengths, voltages, wattages, heated and unheated sections, hot-tip or cool-tip construction, built-in or external thermocouples, straight or 90-degree lead exits, stainless steel braid, flexible armor, post terminals, mounting flanges and threaded NPT fittings. Request a custom split sheath cartridge heater quotation with the heater diameter, length, voltage, wattage, lead style, operating temperature and application details.
How To Order Cartridge Heaters
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