Galden HT 135

What is Galden HT 135?

Galden HT 135 is ideal for heating and cooling operations thanks to its outstanding characteristics, such as superior thermal stability and reliable dielectric performance.

Key Features of Galden® HT 135

Galden® HT 135 is an inert, dielectric perfluoropolyether (PFPE) heat-transfer fluid with a nominal boiling point of 135°C. It provides a balance between low-temperature circulation, reduced volatility and moderate-temperature thermal control.

Galden® HT 135 is particularly suitable for semiconductor equipment, recirculating temperature-control units, chemical and pharmaceutical processing, transformer cooling and specialized vapor-phase heating systems operating within a compatible temperature range.

Technical data sheet of Galden HT 135

Physical

Thermal

Electrical

Optical

Galden® HT Series Comparison

Notes: Dielectric strength is approximately 40 kV at a 2.54 mm electrode gap. Galden® HT fluids have no flash point, fire point or auto-ignition point under standard test conditions. Values shown are typical data and should not be considered guaranteed specifications.

Additional Information

Applications of Galden® HT 135

Galden® HT 135 is an inert, dielectric PFPE heat-transfer fluid with a nominal boiling point of 135°C. It is positioned between Galden® HT 110 and HT 170, providing lower volatility than HT 110 while remaining easier to circulate than the high-boiling HT grades. Galden® HT fluids are used in semiconductor, chemical, pharmaceutical, electrical-cooling, vapor-phase heating, recirculating-chiller and specialized nuclear applications.

1. Semiconductor Process Chillers

Galden® HT 135 can be used in temperature-control units serving semiconductor fabrication tools, including dry etching, chemical vapor deposition and physical vapor deposition equipment.

Its chemical inertness, dielectric performance and resistance to aggressive process environments support stable temperature control near sensitive wafer-processing systems. The 135°C boiling point also provides a greater operating-temperature margin and lower evaporation tendency than HT 55–HT 110.

2. Recirculating Chillers and Temperature-Control Units

HT 135 is suitable for recirculating chillers and thermal-control units used with analytical instruments, electronics-manufacturing equipment and precision industrial machinery.

Its relatively low viscosity supports efficient circulation, while its moderate boiling point helps reduce fluid loss and circuit-pressure problems compared with lower-boiling HT grades.

3. Chemical Reactors and Process Vessels

Galden® HT 135 may be used in closed heating or cooling circuits connected to jacketed reactors, mixing vessels and chemical-processing equipment.

The fluid offers resistance to acids, alkalis, fuels, alcohols, detergents and mineral or synthetic oils. This chemical stability helps reduce undesirable reactions between the heat-transfer fluid, system materials and surrounding process chemicals.

4. Pharmaceutical Process Equipment

HT 135 can support temperature control in pharmaceutical reactors, synthesis systems, laboratory equipment and specialized production processes.

Its non-flammability, low moisture absorption and chemical inertness are valuable where process safety, equipment cleanliness and consistent thermal performance are important. The fluid should remain isolated in a properly designed closed heat-transfer circuit unless the specific process has been otherwise qualified.

5. Transformer and Power-Electronics Cooling

Galden® HT 135 can provide heat removal and electrical insulation in compatible transformers, converters, power supplies and other energized electrical systems.

Galden® PFPE fluids have a typical dielectric strength of 40 kV across a 2.54 mm gap and volume resistivity of approximately 1.5 × 10¹⁵ Ω·cm. They also have no flash point, fire point or auto-ignition point under standard test conditions.

6. Supercomputer and High-Density Electronics Cooling

The fluid may be used in indirect or direct-contact thermal-management systems serving supercomputers, electronic assemblies and other high-heat-density equipment.

HT 135 is most suitable when the required temperature range is higher than that supported by HT 55–HT 110 but does not require the very low volatility of HT 170–HT 270. The cooling system must be designed around HT 135’s viscosity, vapor pressure and boiling point.

Certificate of Analysis (COA) for Galden HT135

Frequently Asked Questions About Galden® HT 135

1. What is Galden® HT 135 mainly used for?

Common uses include semiconductor process chillers, recirculating temperature-control units, chemical and pharmaceutical equipment, transformer cooling, high-density electronics and industrial vapor-phase heating systems.

2. What is the recommended maximum operating temperature?

For an unpressurized single-phase system, Syensqo recommends selecting a fluid whose boiling point is at least 10°C above the maximum operating temperature. Based on this general guideline, the upper temperature for HT 135 would be approximately 125°C.

The actual limit depends on system pressure, vapor containment, flow conditions and equipment design.

3. Should Galden® HT 135 be used in an open or closed system?

A closed or well-contained circuit is generally preferred. Proper containment reduces fluid loss, prevents contamination and helps maintain stable system pressure and thermal performance.

The reservoir, expansion volume, seals and venting arrangement should be designed for the maximum fluid temperature and corresponding vapor pressure.

4. Can HT 135 be mixed with water, glycol or hydrocarbon oil?

Mixing is generally not recommended. Galden® PFPE has very low water solubility—typically below 20 ppm by weight—and is not intended to function as a homogeneous mixture with conventional water-glycol or hydrocarbon fluids.

Separate liquid phases can interfere with circulation, temperature control and corrosion management.

5. How should a pump be selected for HT 135?

Pump selection should consider the fluid viscosity at the lowest operating temperature, required flow rate, system pressure drop and fluid density.

Syensqo uses approximately 20 cP, equivalent to around 11–12 cSt, as a general pumpability limit for many commercially available pumps. The pump manufacturer should confirm suitability for PFPE fluid and the required temperature range.

6. How often should Galden® HT 135 be replaced?

There is no universal replacement interval. Fluid life depends on operating temperature, contamination, leakage, heater-surface conditions and overall system cleanliness.

Periodic checks should evaluate fluid quantity, appearance, contamination, viscosity and thermal behavior. A condition-based maintenance approach is more appropriate than replacement according to a fixed calendar interval.