High temperature diathermic oil thermoregulation units

Many industrial sectors have to ensure a fine control of process temperatures, in order to allow a constant and efficient production, with the highest quality standard for the products. Thermoregulating units are employed to achieve it, thermostating working fluids bringing and maintaining them to the right temperature levels most suitable for the production cycle: thermoregulation consists of alternate heating and cooling cycles, or just thermostatation keeping a fixed temperature, while production process steps gather and withdraw heat to the fluid. A series of sensors monitoring these temperature variations lead to function changes in the thermoregulating unit, going through the different phases of

  • Heating
  • Cooling
  • Maintaining


Thermoregulating units are then composed by a heating zone, using electric resistances or a gas burner, and by a cooling zone using indirect heat exchange with high efficiency heat exchangers. The heating and cooling circuits are connected by a hydraulic circuit served by a circulating pump. Thermoregulation of working fluids becomes a crucial factor in sectors like the steel mill, components, plastic and rubber and the high performances new materials such as polymeric materials, pressure fusion and foundry, where diathermic oil or pressurized water thermoregulating units are employed for the conditioning of stamps and cylinders, avoiding thermal shocks and unchecked thermal variations that can damage machines, equipments and tools, compromising their right functioning. The smallest thermal fluctuation in the printing phase for these industries can mean huge variations of the tribological and stress and wear performances of materials and products, lowering their life length and increasing required maintenance.


The same thermoregulation need is essential in the food and beverage sector and in the refrigeration industry, where maintaining fixed temperatures is required to guarantee the right conservation of foods and products: highly affordable thermoregulating units are necessary to have a good quality product, but also to ensure the right working conditions without production cycle breakdowns, increasing efficiency and cutting production wastes and downtimes, having always working fluids ready yet at the right temperature. In add, a thermoregulating system allows monitoring and reduction on consumptions, obtaining the maximum with minimum resources and energy deployment. Also having several and different thermoregulating zones is possible, with multizone thermoregulating units able to maintain different temperatures at the same time in different points, making thermoregulation an even more efficient and versatile solution, affordable and suitable for any kind of application.

Another sector where thermoregulation is a must is the chemical/pharmaceutical sector, where thermoregulation technology is at the top level. A constant temperature control of active chemicals used in common medicines and pharmaceutical products must be guaranteed in reactors during productive cycle and synthesis. Indeed, without a fine and accurate temperature thermoregulation during the different steps of product’s synthesis, it would be impossible to obtain the right and necessary chemical reactions for the good product’s outcome.

The most modern industrial thermoregulating units and fine temperature monitoring systems allow several advantages:

  • Homogeneous product’s quality
  • Cut off of production wastes
  • Lower production timing
  • Higher products quality and life length
  • Consumption’s reduction
  • Increased safety for employees

Microprocessors electronic regulators and sensors, with PID regulation, are integrated to manage and monitoring the whole system and fluid’s temperatures: is then possible to set well-defined values of temperatures and others parameters, enabling the unit to automatically manage heating and cooling cycles, activated when needed following the thermal state of the system, to keep the fluid at the most suitable temperature. These set regulators can dialogue with other more complex equipments, using different kinds of communication ports, serial ports and other protocols, so that in the most modern versions thermoregulating units allow having complete remote control systems, keeping in local just the heating, cooling and thermostatation hardware, along with all the safety components for the right functioning of the machinery. In a common global competition market for all kind of industry sectors, these kind of modern thermoregulating units allow to build efficient thermoregulating networks, remote control systems that Tempco has developed in the STB TREG Smart Thermoregulating Box series, to offer an affordable and accurate monitoring due to transmission of all data, thanks to smart terminals allowing the management in remote of any point and of all parameters.

Thermoregulating units are engineered for a wide temperature range, and there are three kind of thermoregulation systems according to the range application:

  • cold water, up to 90°C
  • heated water, up to 140°C
  • diathermic oil, up to 350°C

In a special application of thermoregulating units of the T-REG series, Tempco has recently designed and developed a thermoregulating solution for diathermic oil at high temperature, for a customer who needed to thermoregulate high temperature diathermic oil with wide load’s variations, always maintaining it on a constant temperature of 280/290°C.

Diathermic oil thermoregulating units are generally available in two versions, one for temperatures up to 180/200°C and another one for temperatures up to 350°C. In the two versions the heating electric resistances part is almost the same, while are differing the components for the oil circulating pumps and the kind of heat exchangers employed. Once the 200°C are overpassed, Tempco for low/medium fluid loads employs magnetic-drive circulating pumps, bypassing the problem of mechanical sealing that becomes critical in these conditions. Special pumps with special mechanical seal and high temperatures resistants are instead the best solution for high fluid level loads. Also regarding the heat exchangers, it’s necessary to choose types allowing use with high temperatures, such as blazed nickel heat exchangers or fully welded.

Also accessories and components must be carefully chosen: threaded joints are improper, because high thermal variations and following materials dilatations easily lead to oil losses, while best suitable are weldings and flanges with the right gaskets (such as with reinforced graphite or spirometallic ones), while electric resistances are equipped with security thermostatic control for high temperatures, with low specific loads avoiding oil deterioration.

In this kind of thermoregulation with diathermic oil at high temperature, insulation is preferable to be done with non absorbing materials, that can retain oil losses and fulfillments, wich instead must be free to drain in an apposite gathering bowl. Oil collected in insulation indeed begins an oxidating decomposition process, producing heat that added to the heat produced by the plants can reach the oil fire point temperature, in case air comes in contact with the degraded oil, triggering fires.

Always more often, customers are also requiring integrated systems equipped with circulating pump, for the classic range between 180 and 300 degrees, serving the high affordability series of T-REG units: Tempco designed and developed a full standard range of T-REG units for several fluid loads and temperatures, supplied with frame responding to all regulations and certifications needed. These pumping systems include:

  • Expansion tank
  • Cooling system for the connection tube
  • Manual valves
  • Safety systems such as thermostats, pressure and flow indicators
  • Management panel

If the installation sites have room enough, the open expansion tank in diathermic oil at high temperatures must be installed far from the served pipes, so that the oil temperature in the tank doesn’t exceed 65/70°C: the contact of high temperature oil with ambient air leads indeed to oil cracking and degradation, loosing its original characteristics and cloging up machinery. In case the expansion tank cannot be positioned far from the unit, an integrative cooling system for the connection pipe must be added as well.

In particular, in this solution developed for high temperature diathermic oil, high temperatures are reached and maintained thanks to a heating system with 50 KW capacity, and a cooling section of similar capacity with a water heat exchanger. Technical staff in Tempco has engineered a complete thermoregulating unit including:

  • armoured low voltage electrical resistances
  • high diathermic fluid loads
  • magnetic-drive centrifugal pump
  • high temperature water heat exchangers
  • augmented expansion tank
  • double circulating pump for oil, booster and recirculation
  • alternate integrated heating system with heat recovery module, using steam/oil exchanger
  • armoured resistances management with statics relès (SCR)

The special application and engineering of the thermoregulating unit allowed to satisfy all customer’s application needs, adding further advantages of energy efficiency and costs reduction, due to the heat recovery integrated module:

  • extremely fine thermoregulation
  • high fluid load range
  • low consumptions in heat recovery execution
  • extreme capacity modularity

The peculiar kind of T-REG configuration and the components chosen by the engineering division of Tempco can as well be employed to achieve an even higher range of fluid loads and higher temperatures, matching any kind of industrial application requirements, with a free study and local survey in order to design the most suitable solution for any industrial thermoregulation need.