What Technical Parameters Need to Be Provided for Customizing Cartridge Heaters with Special Length and Power?

I. Preface

When standard cartridge heaters fail to meet specific application requirements (such as special installation space, heating rate, or medium compatibility), customizing products with special length and power becomes necessary. To ensure the customized heater matches the working conditions, achieves safe and efficient operation, and avoids risks caused by parameter mismatches (e.g., excessive power density, insufficient insulation, or structural incompatibility), customers must provide comprehensive and accurate technical parameters. This document systematically sorts out the core parameters required for customization, with a focus on the correlation between length, power, and other key indicators.

II. Core Electrical Parameters (Directly Determining Power & Length Design)

1. Rated Voltage

Operating voltage (e.g., 220V AC, 380V AC, 24V DC)

Allowable voltage fluctuation range (typically ±10%)

Power supply type (AC/DC); if AC, specify frequency (50Hz/60Hz)

Critical note: Voltage directly affects resistance wire selection-higher voltage requires longer/thinner resistance wire for the same power, which is closely related to the heater length.

2. Rated Power & Power Density

Required rated power (unit: W/KW)

Allowable power deviation (usually ±5%/±10%)

Power density limit (W/cm²): Must specify based on medium (refer to Table 2 in Section II of the power density document)

Air heating: ≤3 W/cm² (bare tube) / 5-8 W/cm² (finned)

Liquid heating: 5-15 W/cm² (depending on flow rate and medium type)

Whether multi-stage power adjustment is required (e.g., high/low gear switching)

3. Resistance Requirements

Cold resistance value (measured at 25℃, ±10% deviation allowed)

Calculation basis: R = U²/P (theoretical resistance for matching voltage and power)

Hot resistance change range (critical for temperature control accuracy)

4. Current Parameters

Rated operating current (calculated as I = P/U)

Maximum allowable inrush current (to avoid power grid impact)

Current stability requirements (e.g., no obvious fluctuation during operation)

III. Dimensional & Structural Parameters (Key for Installation & Heat Transfer)

1. Length Specifications (Must Be Precise to ±0.5mm)

2. Tube Diameter & Wall Thickness

Outer diameter (common: 6mm/8mm/10mm/12mm; special sizes available)

Wall thickness (0.8mm/1.0mm/1.2mm; thicker walls for high-pressure environments)

Tolerance requirements (e.g., ±0.1mm for precision equipment)

3. Shape & Bending Requirements

Basic shape: Straight tube / U-shaped / Multi-U-shaped / Custom curved shape

Bending parameters (if applicable): Bending radius (minimum 3× tube diameter), number of bends

Special structural requirements: Avoid sharp corners (prone to stress concentration)

4. Installation Structure

Fixing method: Threaded installation (specify thread size: M8/M10/M12/M16/M20) / Flange installation (specify flange size and hole position) / Welding installation (welding material and process requirements)

Terminal design: Lead wire length (minimum 100mm) and material (silicone wire/PTEF wire), terminal type (tab/terminal block/connector), waterproof treatment requirements for terminals

IV. Material Parameters (Matching Medium & Temperature)

1. Shell Material (Determined by Medium Corrosion & Temperature)

2. Resistance Wire Material

Nickel-chromium alloy (Cr20Ni80): Suitable for high temperature (≤1200℃) and long life requirements

Iron-chromium-aluminum alloy (0Cr25Al5): Cost-effective, suitable for medium temperature (≤800℃)

Special alloy: For ultra-high temperature (>1200℃) or corrosion-resistant environments

3. Insulation & Sealing Materials

Insulation material: Magnesium oxide powder (purity ≥99%, chloride ion content <30ppm for liquid heating)

Sealing material: Silicone (≤200℃) / PTFE (≤260℃) / Epoxy resin (≤150℃) / Glass seal (≤500℃)

Sealing grade: IP65 (waterproof) / IP68 (submersible) / Explosion-proof sealing (for hazardous environments)

V. Temperature & Performance Parameters (Guarantee Heating Effect)

1. Temperature Requirements

Maximum operating surface temperature (must match shell material and power density)

Medium heating target temperature (e.g., heat water to 80℃, air to 300℃)

Temperature control accuracy (±1℃/±5℃, critical for precision equipment)

Ambient temperature range (operating environment: -20℃~50℃/50℃~100℃)

2. Thermal Performance

Heat-up time requirement (e.g., heat 50L water from 20℃ to 80℃ within 30 minutes)

Thermal response time (time to reach 90% rated temperature)

Temperature uniformity (maximum temperature difference between different parts of the heating section)

3. Service Life & Reliability

Design service life (e.g., 10,000 hours continuous operation)

Number of cold-heat cycles (e.g., 5,000 cycles of switching on/off)

Thermal shock resistance (e.g., withstand rapid temperature change from -20℃ to 300℃)

VI. Environmental & Safety Parameters (Avoid Operation Risks)

1. Working Environment Details

Medium type: Air (dry/humid/corrosive) / Liquid (water/oil/chemical solution, specify pH value and corrosivity) / Solid contact (e.g., mold heating)

Pressure condition: Atmospheric pressure / High pressure (specify pressure value, e.g., 1.6MPa) / Vacuum (specify vacuum degree)

Special environment: Dust, salt fog, vibration (specify vibration frequency and amplitude)

2. Safety & Protection Requirements

Protection grade: IP rating (e.g., IP67 for outdoor use, IP68 for submersible use)

Explosion-proof grade: ExdⅡCT4/ExiaⅡCT6 (for flammable and explosive environments)

Safety functions: Anti-dry heating protection (whether to integrate temperature sensor), over-temperature power-off, leakage protection

Certifications required: CE/UL/RoHS/ISO (industry-specific certifications such as food-grade FDA, medical-grade ISO 13485)

VII. Special Customization Requirements

1. Surface Treatment

Polishing requirement (electropolishing for food-grade/anti-scaling, roughness Ra ≤0.8μm)

Special coating: PTFE coating (anti-corrosion/anti-sticking) / Ceramic coating (high temperature resistance) / Chrome plating (wear resistance)

Surface color (e.g., black oxidation treatment for air heating to improve emissivity)

2. Integrated Functions

Whether to integrate temperature sensor (thermocouple K/J type, PT100 RTD)

Sensor installation position (embedded in heating section/attached to shell)

Signal output type (analog signal 4-20mA/digital signal)

3. Mechanical Performance

Anti-bending strength (for curved heaters)

Vibration resistance (e.g., meet IEC 60068-2-6 standard)

Impact resistance (e.g., 1m drop test for portable equipment)

VIII. Testing & Acceptance Standards

1. Factory Test Items

Insulation resistance test (≥100MΩ at 500V DC)

Withstand voltage test (2×rated voltage +1000V, no breakdown for 1 minute)

Power test (actual power within allowable deviation)

Leakage current test (≤0.5mA for household use, ≤1mA for industrial use)

Medium compatibility test (e.g., salt spray test for 48 hours for corrosive environments)

2. Acceptance Criteria

Appearance: No scratches, deformation, or rust on the shell; tight sealing at terminals

Performance: Meet heat-up time and temperature control accuracy requirements

Durability: Accelerated life test (e.g., 1000 hours continuous operation without failure)

IX. Supporting Documents & Logistics Requirements

1. Technical Documents

Detailed 2D/3D drawings (marking key dimensions: length, diameter, installation position)

Material certification report (e.g., stainless steel material certificate, food-grade certification)

Test report (insulation, power, withstand voltage test data)

User manual (installation instructions, maintenance precautions, safety warnings)

2. Packaging & Logistics

Packaging requirement: Anti-collision packaging (foam + carton) for long-distance transportation; moisture-proof packaging for humid environments

Storage conditions: Store in dry and ventilated environment, avoid corrosive gas

Delivery time requirement (custom production cycle: usually 7-15 working days)

X. Key Notes for Customization

Power-Length Correlation: For a fixed power density, longer heating section length allows higher total power (P = q×π×D×L). Avoid blindly increasing power without adjusting length, as this will lead to excessive power density and shorten service life.

Medium Adaptability: Liquid heating requires higher sealing grade and corrosion-resistant materials; air heating focuses on heat dissipation (e.g., adding fins) and oxidation resistance.

Safety Margin: Reserve 10-20% safety margin for power and temperature parameters to adapt to fluctuations in actual working conditions.

Communication with Manufacturers: Provide actual working condition photos or sample drawings if possible; technical personnel can optimize the design (e.g., adjust tube diameter, increase cold end length) based on on-site constraints.

By providing the above parameters in detail, manufacturers can accurately customize cartridge heaters with special length and power that match the application scenarios, ensuring safe, efficient, and long-term stable operation. It is recommended to conduct pre-customization technical communication to resolve potential parameter conflicts (e.g., excessive power density for a given length) and optimize the solution for cost-effectiveness.