Thermal Oil Heaters

Thermal and Pressure Engineering are well known in the industrial, mining and commercial sectors for designing and making efficient and durable thermal oil heaters. These types of heaters are used in a variety of industries where the medium that requires heating is unable to be heated directly, or the medium would change form if heated directly (like water will turn to steam at 100 degrees celsius). Thermal oil heaters are used in gold mines, some dry cleaning applications, heating of buildings, etc.

Benefits and Advantages of Thermal Oil Heaters

• Can come in both the standard vertical or horizontal construction;
• Can achieve temperatures of over 300°C at atmospheric pressure;
• Suitable for Diesel, Heavy Fuel Oil (HFO), LPG, Natural Gas, Electric or Solid Fuel (biomass);
• Suitable for mineral and synthetic oils;
• Optional temperature level set-points;
• Low film temperature, ensures long life of the thermal oil;
• Easy to operate and provides fully automatic operation;
• Low maintenance cost;
• Clean and safe in operation;
• Low thermal fluid resistance;
• High flue gas velocity, resulting in good heat transfer;
• High efficiency (up to 88%);
• Triple draw flue gas principle;
• Removable front cover;
• Frost resistant (up to -30°C);
• Gas-tight welded inner jacket on all heaters;
• Thick insulated jacket that minimises radiant heat loss;
• Outer steel plate jacket; and
• The thermal oil heater can come with an inspection hatch if requested.

Advantages Of Thermal Oil Heating Over Steam

• No corrosion and no risk of damage from sub zero temperatures;
• Water treatment is not required (if looked after, thermal oil can be used for years);
• Quiet operation (no steam stroke or flash steam noise);
• Minimal system pressure;
• Easy to operate (does not require steam boiler certified staff);
• Possibility for indirect hot water and steam generation.

Technical Data for Thermal Oil Heater

Applications of Thermal Oil Heaters

Thermal Oil Heaters are used in the following industries:

• Gold Mining Industry – part of the elution system;
• Metal Processing Industry – for pickling baths, varnishing plants, degreasing systems;
• Chemical Industry – for autoclaves, reaction tanks, mixing plants;
• M.D.F. Board Manufacturers – Paper – Pasteboard Industry – Wood or laminate presses, hot presses, chip board pressers, dryers;
• Construction Material Industry – for heating of form works, brick works, dry chambers;
• Tar Manufacturing Industry – for roofing felt plants, store and mixing installations, tank depots;
• Food Industry – for baking plants, distilling, fat-splitting, pasteurising;
• Textile Industry – coating, colouring, clalanders, stenters, dryers and hot flues;
• Soap and Detergent Industry – for autoclaves, spray and drying columns, soaping plants;
• General Heating Applications

Construction of Thermal Oil Heaters

This style of electric thermal oil heater consists of a tubular coil through which a regulated flow of thermal oil is pumped. The coil is arranged in two sections – an inner coil and an outer coil. The inner coil forms the combustion chamber, where the radiant and convection heat transfer occurs. The space between the inner and outer coil and the space between the outer coil and casing form the flue gas passages where convection heat transfer occurs, cooling the combustion gases to the required temperature prior to passing out of the combustion chamber via the flue outlet.

The transfer of heat to oil takes place in the tubes which form the inner and outer coils. The thermal oil enters the heater via the inlet header passing to the outer coil via the inner coil. The heated oil flows to the inner coil outlet then onto the outlet header through to the system pipe work.

Safety and Interlocks

1. The flow switch, which monitors the flow of thermal oil into the coil.
2. The oil level switch located in the system expansion tank, which monitors the system oil level.
3. The stack and high limit overheat thermostats, which monitor the coil operating temperature.
4. Safety valves, which ensure that the heater does not become over pressurised.
5. Cold start thermostat, which reduces the burner capacity until the minimum viscosity of thermal oil is achieved.
6. Combustion is denied until the thermal oil pump is running properly.
7. Flow monitoring by type-tested differential thermal pressure system.
8. If the minimum thermal oil flow is not achieved, the burner is immediately disabled.
9. All safety interlocks give both optical and acoustic alarm. The source of the alarm is shown on the HMI.