Single head heating tube (also known as single head electric heating tube or heating rod) is a key component in industrial heating systems, widely used in fields such as mold heating, plastic machinery, chemical equipment, etc. Designing and producing a high-quality single head heating tube requires comprehensive consideration of multiple aspects such as material selection, structural design, process control, and performance verification. The following is a detailed design and production process:
1、 Design phase
1. Determine the basic parameters
Power demand: Calculate the required power based on the temperature requirements of the heating object. For example, when the working temperature of the mold is 300 ℃, the recommended surface load is 3W/cm ².
Size specifications: including diameter (commonly 3-25mm), length (20-2000mm), and operating voltage (36V-380V).
Installation method: Determine the fixing method such as flange, thread or direct insertion, and ensure that the gap with the mold hole is controlled within 0.05mm to optimize heat dissipation.
2. Structural design
Heating wire layout: Nickel chromium alloy wire is wound around a magnesium oxide core rod, and uniform heating or multi-stage temperature control is achieved by adjusting the winding density.
Internal structure: Optional built-in thermocouple (J/K type) for precise temperature control, or designed to extend the non heating section to meet special scenario requirements.
Insulation treatment: Fill high-purity magnesium oxide powder and compress it to ensure that the insulation resistance between the heating wire and the metal shell is ≥ 50M Ω.
2、 Material selection and preparation
1. Core materials
Metal shell: Choose the material according to the temperature (such as 304 stainless steel with a temperature resistance of 400 ℃, 310S with a temperature resistance of 700 ℃).
Heating element: Nickel chromium alloy wire (high temperature resistance, stable resistance) or iron chromium aluminum wire (lower cost).
Insulation medium: Magnesium oxide powder (high purity, good thermal conductivity).
2. Auxiliary materials
Lead out electrode: High temperature fiberglass lead (standard 300mm) or pure nickel lead (high-power scenario).
Head component: heat-resistant sealing material (such as epoxy resin).
3、 Production process flow
1. Processing of main pipe
Cutting and Forming: Cut the stainless steel tube to the design length and ensure uniform wall thickness through cold pressing forming.
Welding treatment: argon arc welding is used for sealing, and the weld seam must be free of cracks and meet the air tightness standard.
2. Internal assembly
Wire winding and filling: The alloy wire is wound around a magnesium oxide core rod, inserted into the main tube, filled with magnesium oxide powder, and compressed by the machine to discharge air.
Lead connection: Weld the electrode and install a temperature measuring sleeve (if necessary).
3. Surface treatment
Cleaning: Remove residual metal slag and oxides from welding.
Coating: chrome plated, electroplated zinc plated, or sprayed to enhance corrosion resistance.
4、 Performance testing and optimization
1. Key testing items
Electrical performance: Cold insulation resistance test (≥ 50M Ω), leakage current detection.
Thermal performance: heating time test (≤ 15 minutes to rated temperature), power deviation verification (± 5% -10%).
Mechanical strength: pressure test (1.5 times working pressure holding).
2. Common problem optimization
Life improvement: Improve heat dissipation by reducing the gap between installation holes (such as 0.05mm) to avoid dry burning.
Temperature uniformity: Adopting uniform heating type wire winding design or power regulation type structure.
5、 Application and maintenance suggestions
1. Typical application scenarios
Mold heating: embedded in a metal plate to maintain the temperature of the molten material.
Liquid heating: used in chemical reaction vessels or pharmaceutical production lines.
2. Precautions for use
Moisture proof treatment: Avoid long-term storage in humid environments.
Regular inspection: Monitor lead aging and insulation performance degradation.
Through scientific design, strict process control, and comprehensive performance verification, efficient and durable single head heating tubes can be produced. In practical applications, parameters need to be customized according to specific needs. For example, high-power scenarios (>20W/cm ²) require imported technology, while precision temperature control systems recommend models with built-in thermocouples.