Distributed Wattage Cartridge Heater for Sealing Bars
In vertical form-fill-seal (VFFS) and flow wrapping machinery, standard heaters often fail to seal the outer edges of the package due to heat loss at the ends of the sealing bar. Hongtai Distributed Wattage Cartridge Heaters solve this problem.
By expertly winding the resistance wire tighter at both ends and looser in the middle, we create a custom heat profile that compensates for end-loss. This ensures a uniform temperature across the entire sealing bar heater face, resulting in perfect seals every time. Additionally, our “Swaged-in” lead construction is specifically engineered to withstand the high-frequency vibration of packaging jaws.
Key Technical Features:
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Heat Profile: Distributed Wattage (Higher power at ends, lower in center).
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Vibration Resistance: Internal swaged-in lead connection resists breakage at 200+ cycles/minute.
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Uniformity: Maintains ±3°C uniformity across the sealing surface.
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Sheath: Stainless Steel 304/316L for food safety environments.
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Response: High watt density for rapid recovery between cycles.
1. Technical Specifications & Winding
We customize the winding distribution based on your sealing bar’s mass and length.
| Parameter | Standard Specification | Customizable Options |
| Diameter | 8mm, 10mm, 12mm, 1/2″, 5/8″ | Custom Metric/Imperial |
| Power Distribution | 15% – 25% Higher at Ends | Custom Heat Map |
| Length | 100mm to 1000mm | Long bars for wide web |
| Lead Connection | Swaged-in (Vibration Proof) | Crimped (Static Use) |
| Lead Wire | Teflon (PTFE) for movement | Silicone / Fiberglass |
| Watt Density | 10 – 15 W/cm² | High Density |
2. The Science of Distributed Wattage
A standard heater generates heat evenly, but a metal sealing bar loses heat rapidly at the ends where it bolts to the machine. This creates “cold ends” and weak package seals.
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Hongtai Solution: We analyze your sealing bar length. For a 300mm heater, we might wind the first and last 40mm at 20 Watts/inch and the center 220mm at 10 Watts/inch. This balances the thermal loss, creating a flat temperature curve.
3. Vibration Resistant Leads
Packaging jaws move rapidly (opening/closing). Standard crimped leads often snap at the exit point due to metal fatigue.
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Swaged-in Leads: The flexible lead wires are inserted deep into the heater body before the compaction process. They are mechanically locked inside the MgO, eliminating the weak point at the exit. This is mandatory for high-speed cartridge heaters for packaging machines.
4. FAQ
Q: How do I know which end is hotter?
A: Distributed wattage heaters are typically symmetrical (hot at both ends, cooler in middle). If you need an asymmetrical profile (hotter on just one side), please mark the drawing clearly.
Q: What information do you need to design this?
A: We need: 1. Heater Diameter & Length; 2. Voltage/Wattage; 3. The length of the sealing bar; 4. Cycle rate (to determine lead wire type).
Q: Do you stock these?
A: Because the “distribution” depends on your specific machine’s heat loss, these are almost always Make-to-Order. However, we can produce samples in 5-7 days.
