Combined heat exchangers are mainly used for heating heavy-oil storage tanks. Of course, they can be used for all fluids which can be used for tubular heat exchangers and electrical flow-type heaters.
I. Water
- Drinking water, max. surface load depending on the water hardness 4 – 6 W/cm²
- Circulating and/or heating water, max. surface load approx. 10 W/cm²
- Softened water; observe the maximally admissible chloride content, max. surface load approx. 19.0 W/cm²
- Ultra-pure water; here, a low-pocket or pocket-free design with a defined surface quality is useful in most cases.
- Fully desalted water; here, non-ferrous heavy metals should not be used, maximum surface load approx. 10 W/cm²
II. Oil
- Heavy oil, not pumpable in a cold condition, maximum surface load between 1 and 2 W/cm² depending on the quality
- Hydraulics oil, maximum surface load approx. 0.6 – 1.2 W/cm²
- Lubricating oil, steam turbine oil, max. surface load approx. 1 W/cm²
- Insulating oil, maximum surface load approx. 0.3 – 0.6 W/cm²
- Heat transfer oil, film temperature calculation acc. to DIN 4754 required, maximum surface load approx. 10 W/cm² depending on the flow velocity and oil
- Fuel oil, diesel, heating to max. 40 °C, max. surface load approx. 4 W/cm²
III. Gases
- Air
- Natural gas
- Flue gas
- Nitrogen
he fluid to be heated and the application temperature mainly define the materials which can be used for the unheated and/or heated surfaces. Otherwise, corrosion may quickly result in a failure of the combined heat exchanger, for example.
Materials of the wetted and unheated components
- Carbon steel
- Corrosion-resistant stainless steel
- Heat-resistant stainless steel
- Titanium, Hastelloy, special materials
- Brass
Materials of the heating surface:
- Carbon steel
- Corrosion-resistant stainless steel
- Heat-resistant stainless steel
- Titanium, Hastelloy, special materials
Miscellaneous heating elements can be used for combined heat exchangers. Depending on the application, they will be selected by us.
I. Heating elements
- Tubular heaters, diameter 8.5 or 16 mm
- Cartridge-type heaters, diameter 16, 18 or 25 mm
- Exchangeable heating elements, including a protective tube, diameter 25, 42 or 65 mm
We are prepared to agree with you on the type and position of the fluid connections. The following connections are available:
I. Fluid connections
- Standard flanges (DIN, ASME, SAE etc.)
- Female or male thread connections
- Clamp flanges
- Sterile flanges
- Dairy-type pipe connections
Available design models for electrical equipment and controlling of the combined heat exchanger are:
I. Design models
- Indoor or outdoor installation
- Hazardous area (zone 1 or 2, 21 or 22)
- Non-harzardous area
- Type of protection IP54 or better
- Switchgear cabinet for wall or floor mounting
- Steel sheet connection housing, powder-coated or stainless steel
- Electronic or electromechanical control
- Communication with higher-level control system by floating contacts, standardized signal or bus
