Core Value
The Bayonet Spring Loaded Thermocouple Temperature Sensor is a critical temperature sensing element engineered for dynamic industrial environments where vibration and thermal expansion can disrupt accurate temperature readings. Designed specifically for plastic injection molding machines, extruder barrels, hot runner systems, and die blocks, this sensor utilizes a specialized adjustable spring and bayonet cap locking mechanism. This design guarantees the measuring tip remains under constant compression against the target surface, eliminating insulating air gaps and providing instantaneous, highly accurate thermal feedback to your PID controller.
Available in industry-standard Type J and Type K calibrations (as well as RTD PT100 for higher precision), these sensors are housed in durable 304 stainless steel tubing. The flexible lead wires are insulated with high-temperature fiberglass and shielded with a rugged stainless steel overbraid to prevent mechanical abrasion in busy factory settings. Whether measuring deep inside an extruder barrel or monitoring a packaging heat-seal jaw, the adjustable spring allows a single sensor to adapt to various hole depths, reducing your spare parts inventory. BACKED BY EXTENSIVE SENSOR MANUFACTURING EXPERIENCE and UNDERGOES MULTIPLE RIGOROUS QUALITY CHECKS to ensure zero thermal drift and maximum durability.
✓ Positive Surface Contact: The heavy-duty compression spring pushes the sensing tip firmly against the blind hole bottom, ensuring rapid thermal response and eliminating air-gap lag.
✓ Adjustable Immersion Depth: The twist-lock bayonet cap threads up and down the spring, allowing one sensor to fit multiple hole depths.
✓ Vibration Resistant: The spring mechanism absorbs machine shock and vibration (common in extruders), preventing tip damage and signal loss.
✓ High-Temperature Wiring: Standard fiberglass insulated wires with stainless steel overbraid protect against heat (up to 400°C/750°F) and physical abrasion.
✓ Grounded & Ungrounded Junctions: Available in grounded configurations for ultra-fast response, or ungrounded to prevent electrical noise interference.
✓ Reliable Quality: Engineered to match or exceed the performance of top-tier European thermal components, ensuring exact PID control loop stability.
✓ Quality Assured: UNDERGOES MULTIPLE RIGOROUS QUALITY CHECKS including millivolt output calibration, dielectric strength testing, and mechanical spring tension verification.
✓ Global Compliance: CE, RoHS compliant, and compatible with all major global temperature controller brands.
Technical Specifications & Performance Data
| Parameter | Standard Value | Customizable Range | Notes |
| Sensor Calibration | Type J / Type K | Type T, E, or RTD (PT100/PT1000) | Type J is standard for most plastics machinery |
| Temperature Range | 0°C to 400°C (32°F to 750°F) | Up to 600°C for special builds | Governed by wire insulation and junction type |
| Bayonet Cap Size | 12 mm (Standard slotted) | 12.5 mm, 14 mm, 15 mm, 1/8″ BSP | Single or double slot twist-lock designs |
| Probe Tip Diameter | Ø 4.5 mm / Ø 5.0 mm | Ø 3 mm to Ø 8 mm | Flat tip, 118° drill point, or conical tip |
| Probe Tip Length | 10 mm to 50 mm | Built to machinery specifications | 304 or 316 Stainless Steel casing |
| Spring Length | 200 mm (8 inches) | 100 mm to 500 mm | High-tension spring steel |
| Lead Wire Material | Fiberglass + SS Braid | Teflon (PTFE), Polyimide, Silicone | SS braid provides superior mechanical protection |
| Lead Wire Length | 1000 mm / 2000 mm | Custom tailored to machine routing | Spade terminals, standard male/female plugs |
| Junction Type | Grounded | Ungrounded (Isolated) | Grounded = Faster response; Ungrounded = Less noise |
| Accuracy Class | Class 2 (Standard) | Class 1 (High Precision) | IEC 60584 / ASTM E230 standards |
Industrial Applications & Solutions
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Plastic Injection Molding: Monitoring nozzle and barrel temperatures to maintain exact polymer melt viscosity.
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Extrusion Machinery: Providing rapid thermal feedback from multiple zones along the extruder barrel to prevent material degradation.
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Packaging Equipment: Temperature sensing in heat-seal jaws, hot melt glue systems, and blister packaging thermoformers.
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Die Casting & Hot Runners: Inserted into blind holes in metal dies to monitor internal tooling temperatures.
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Food Processing & Rubber Presses: Reliable thermal tracking in vibrating, high-cycle industrial presses.
High-Performance Sensors vs Standard Market Options
| Feature | Our Bayonet Thermocouples | Standard Market Sensors | Your Advantage |
| Spring Tension | High-Carbon Fatigue-Resistant Spring | Weak/Cheap Alloy Spring | Maintains constant tip pressure for years; no temperature reading drops. |
| Wire Shielding | 304 Stainless Steel Tight Overbraid | Loose/Thin Galvanized Braid | Prevents wire snapping during machine maintenance and abrasive rubbing. |
| Junction Welding | Precision TIG Welded Tip | Hand-crimped or poorly welded tip | Ultra-fast thermal transfer, zero signal intermittence. |
| Cap Machining | CNC Machined Solid Bayonet Cap | Stamped Sheet Metal Cap | Smooth twist-lock engagement, won’t jam inside the machine adapter. |
| Quality Assurance | MULTIPLE RIGOROUS QUALITY CHECKS | Spot checked only | Plug-and-play reliability straight out of the box. |
Installation & Handling Guidelines
- Setting Immersion Depth: Measure the depth of the hole on your machine barrel. Twist the bayonet cap along the spring so that the distance from the probe tip to the cap is slightly longer (about 5-10 mm) than the hole depth.
- Locking Mechanism: Insert the probe tip into the hole, push down to compress the spring, and twist the cap into the mating bayonet adapter pins on the machine to lock it in place.
- Verify Tension: Once locked, the spring should be visibly compressed. If the spring is loose, remove the sensor, twist the cap further up the spring, and reinstall.
- Wiring Polarity: Ensure correct polarity when wiring to the controller. For Type J (Iron/Constantan), the standard color code is typically White (+) and Red (-) in North America, or Black (+) and White (-) in IEC standards. Always verify your regional color code.
- Avoid Sharp Bends: Do not kink or sharply bend the transition area where the rigid probe meets the flexible spring and wire, as this can sever the internal thermocouple leads.
Customer Success Stories
Case 1: Plastic Pipe Extrusion Plant (Malaysia)
- Application: Multi-zone temperature control on high-speed PVC extruder barrels.
- Challenge: Heavy machine vibration was causing standard sensors to back out of their holes, creating air gaps that led to falsely low temperature readings and subsequent polymer overheating.
- Solution: Type J Spring-Loaded Bayonet Thermocouples with high-tension springs and dual-slot CNC caps.
- Results: TEMPERATURE FLUCTUATIONS ELIMINATED. “The aggressive spring tension ensures the tip never loses contact with the barrel, even at maximum RPM. Our scrap rate due to thermal degradation dropped by 85%.”
Case 2: Custom Injection Molding Facility (UK)
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Application: Hot runner nozzle temperature monitoring.
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Challenge: Maintenance teams were stocking 15 different sensor lengths for various molds, tying up capital in spare parts.
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Solution: Adjustable Spring-Loaded Bayonet Sensors (200mm spring length).
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Results: INVENTORY REDUCED BY 60%. “Because the bayonet cap threads up and down the spring, we replaced 15 fixed-length SKUs with just 3 adjustable SKUs. The stainless steel braiding is exceptionally durable against our maintenance handling.”
Pricing & Procurement Options
- Standard Production: Low MOQ available for standard configurations. Tiered volume discounts for 100+ unit OEM orders.
- Lead Times: Standard Catalog Items (Type J/K, 12mm cap, 2m wire): In stock, 3-5 days. Custom probe tips, special spring lengths, or RTD PT100 builds: 7-10 days.
- Global Logistics: Carefully coiled and packed in anti-static, shock-absorbing packaging to ensure delicate wire junctions are protected during express air freight.
- Sample Orders: Available upon specification confirmation. Every sensor UNDERGOES MULTIPLE RIGOROUS QUALITY CHECKS prior to dispatch.
Global Certifications & Compliance
- CE Marking
Fully compliant with European safety and environmental standards. - LVD Compliance
Low Voltage Directive tested for continuous thermal load safety. - RoHS Compliant
Constructed using environmentally safe, lead-controlled brass alloys. - ISO 9001
Certified quality control covering CNC machining, coil pressing, and electrical testing.
Quality Documentation: Certificate of Conformity (COC) and insulation resistance test reports included.
Comprehensive After-Sales Support
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- Warranty: 1-Year Comprehensive Warranty covering internal heating element and built-in sensor.
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Technical Support: Application engineers available for wattage distribution calculation, thermocouple calibration, and nozzle fitting assistance.
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Global Response Network: BACKED BY 30+ YEARS MANUFACTURING EXPERIENCE with technical inquiry feedback within 2 hours.
Ready to Optimize Your Injection Molding?
Next Steps:
- 📧 Request Custom Quote – Send your nozzle dimensions, wattage, voltage, and HT-CLW-450 drawing requirements.
- 🔧 Free Design Consultation – Work with our thermal engineers to optimize heat distribution and lead insulation.
- 📦 Order Test Samples – Evaluate thermal performance on your injection molding machine.
- 📞 Contact Hot Runner Experts – Response within 2 hours
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