Comparison Between Thermal Flow Switches and Piston Flow Switches in High-Temperature Environments‌

Comparison Between Thermal Flow Switches and Piston Flow Switches in High-Temperature Environments‌

1. High-Temperature Suitability of Thermal Flow Switches‌

Operating Temperature Range‌: Standard models support -20°C to 90°C, while upgraded versions (e.g., NK300 series) can withstand up to ‌150°C‌.

Mechanical Wear-Free Design‌: Based on thermal diffusion principles, with no moving parts, eliminating mechanical fatigue issues at high temperatures.

Material Optimization‌: Stainless steel housing with anti-corrosion coatings ensures resistance to thermal oxidation and deformation.

Case Example‌:

Chemical Reactor Monitoring‌: A thermal flow switch (SIY10-150℃) was used in a high-temperature chemical process to monitor coolant flow, ensuring stable operation at ‌120°C‌ without performance degradation over five years.

2. Limitations of Piston Flow Switches in High-Temperature Applications‌

Mechanical Constraints‌: High temperatures can cause piston sticking or spring failure, with a typical ‌maximum temperature limit of 90°C‌.

Material Challenges‌: Plastic housings (e.g., POM) may soften at high temperatures, while stainless steel versions are prone to thermal expansion affecting accuracy.

Maintenance Requirements‌: High temperatures accelerate lubricant evaporation, necessitating frequent cleaning or part replacement.

Case Example‌:

Lubrication System in Power Plants‌: A piston flow switch was used in a ‌80°C‌ oil lubrication system but required ‌quarterly maintenance‌ due to increased wear from thermal stress.

3. Comprehensive Comparison‌

Parameter‌ ‌Thermal Flow Switch‌ ‌Piston Flow Switch‌

Max Temperature‌ ‌150°C‌ (special models) ‌90°C‌ (standard models)

Stability‌ Resistant to thermal drift Susceptible to thermal expansion

Maintenance‌ Maintenance-free Requires periodic inspection

4. Selection Recommendations‌

Choose Thermal Flow Switches‌ for:

Permanent high-temperature applications‌ (e.g., ‌steam pipelines‌, ‌high-temperature chemical reactors‌).

Long-term stability‌ without frequent maintenance.

Choose Piston Flow Switches‌ for:

Short-term or intermittent high-temperature use‌ (e.g., ‌temporary industrial cooling systems‌).

High-pressure environments‌ where thermal switches may not be rated for extreme conditions.

Case Example‌:

Steam Boiler Protection‌: A thermal flow switch (NK300-150℃) was deployed in a ‌140°C‌ steam system, providing reliable flow monitoring for ‌three years‌ without failure.

Conclusion‌

Thermal flow switches outperform piston types in ‌high-temperature durability‌ due to their ‌wear-free design‌ and ‌extended temperature range‌. However, piston switches remain viable for ‌short-term high-temperature applications‌ where ‌mechanical robustness‌ is prioritized over longevity.