Optimise machine performance – with FUNKE electric oil pre-heaters

The viscosity of oils and fire-resistant fluids significantly increases at lower temperatures. This can cause extremely high pressure loss in pipelines, filters and cooling systems. When systems are cold-started, especially oil/air cooling systems set up outdoors, the high start-up pressure can cause severe damage to pumps, filters, heat exchangers and other components. If the oil in the tank has been brought to a defined operating temperature by an oil pre-heater, however, starting up systems and machines is considerably easier. As there is a trend towards offline cooling and filtering in larger hydraulic systems anyway, for example, integrating an oil pre-heater into the circuit does not present any problems.

How FUNKE electric oil pre-heaters work

In the electric oil pre-heater, the fluid to be heated flows through a bundle of U-shaped curved heating rods. The spacing of the deflection segments is configured to ensure that the flow velocity is adequate even at the permitted minimum flow rate. The standard heat area load is approx. 2 W/cm². At the minimum flow rate and an input oil temperature of 60°C, the heating rod surface temperature is only 110°C. It is therefore significantly below the coking temperature of the oil. The temperature limiter integrated into the electric oil pre-heater switches off at 80°C.

Application areas of the FUNKE electric oil pre-heater

Electrical energy is used to heat oils and fire-resistant fluids of fluid group 2 in accordance with PED 97/23/EC and emulsions. Oil pre-heaters are used predominantly in machines and systems that are used outdoors and in test benches that require defined oil temperatures. FUNKE supplies a proven modular programme of oil pre-heaters in 11 sizes for the typical requirements in mechanical and system engineering with heating capacities of 3 to 100 kW. Special designs as high-temperature devices up to 200°C and reduced heating area loads of 1 W/cm² are also available.

Technical data, FUNKE electric oil pre-heaters

  • Heating insert with curved heating rods (like U-tube bundle)
  • Housing: steel version
  • Equipped with temperature limiter as standard
  • Heating capacity: 3–100 kW
  • Max. operating pressure: (6 kW / >9 kW) 25 / 16 bar
  • Max. end temperature: 80°C
  • High-temperature design possible with max. 200°C end temperature



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