Maximizing Heater Performance
There are a couple ways to maximize existing heater performance. If these don't solve your issues, you may have to look into redesigning your heating process.
General tips to optimize heater performance:
| Avoid heater contamination |
Contamination is the most frequent cause of heater failure. In vacuum applications, place the terminals outside the vacuum if possible.
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| Protect leads and terminations from high temperature |
Use standard fiberglas-insulated lead wire up to 500degF. If lead is exposed to higher temperature, high temp lead wire or ceramic bead insulation should be used. And how about an additional cold section?
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| Protect leads from excessive movements |
Specify a lead protection option (examples: clip support, stainless steel braid, right angle headers) |
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Proper heater selection and sizing
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Wattage should be matched to actual application to limit ON / OFF cycling. A tight fit minimizes air gaps and reduces hot spotting.
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Grounding of equipment
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For safety reason ground all heating equipment.
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Prevent excessive heater cycling
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Full expansion and full contraction of the heater is detrimental to heater life. This can happen with simple On / Off controls. A better way is to use a PID temperature controller and a SCR (zero-cross or phase-fired) power controller.
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Select sheath material and WSI to specs
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Check parameters such as process temperature , flow rate, heater to part fit, materials (solid or fluid)
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Ensure tight connections and limit protections
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Use process temperature sensors (contact or non-contact) for material and high limit sensors for heating elements. PID controllers are better than simple ON/OFF controls or thermostats.
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Maximizing performance of immersion heaters:
- watt density ratings and sheath material need to be compatible with the liquid being heated
- install heaters horizontally near the bottom of the tank to maximize convective circulation. If space limitations require vertical mounting, think about a stirring mechanism.
- The entire heated length of the heater should be immersed all the times. Install a liquid level control in the tank and a overtemperature limit on the heater.
- For best accuracy, responsiveness and exchangability, install the temperature sensor in a thermowell
- Protect the heater from contamination.
- Protect the terminals from moisture and/or add a moisture seal if necessary
- Avoid boiling in restricted area
- Avoid sludge built up on bottom of tank
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