Safe and representative sampling in thermal oil systems according to DIN 4754

Sample cooler for thermal oil maxxtecThe high-temperature sample cooler "samplemaxx" allows a simple, safe and representative sampling of thermal oil samples. Unwanted oil losses due to flow quantities by emptying the measuring lines are avoided by the special Maxxtec circulation system. The sampling is done while the system is in hot operation via a sampling device with water cooling. 

The heat transfer is first circulated through the radiator in order to extract a representative sample from the mainstream can. Subsequently, the sample is cooled below 60 °C, to avoid release of vaporized low-boiling components while the oil sample is discharged. After draining into a suitable sample bottle, a reliable and reproducible analysis can be created. Only thus can a competent assessment of reusability of heat transfer fluids be taken.

By involvement the sampling device with the optionally available connection kit the "samplemaxx" Sample cooler can be easily retrofitted without welding work on existing equipment

As an accessory, a connection kit and / or a mounting kit can be supplied.

Sampling of thermal oil "samplemaxx" in comparison to other systems

With our "samplemaxx" sampling system thermal oil samples can be safely and reliably removed from hot systems in operation.

The new circulation system avoids the loss of oil, which until now inevitably caused by the draining of the supply line. Furthermore, the risk of evaporation of highly volatile components at the taking of samples with the new system switched off, because the sample is cooled in the sample vessel to less than 60 °C before draining.
Backfitting the samplemaxx sampling cooler at existing plants also possible without welding.


Many mistakes can be made at sampling

In many cases, the analysis of heat transfer fluids are adulterated by inadequate or faulty sampling or the use of inappropriate or contaminated  container. The falsified analysis results then in turn lead to incorrect conclusions about the state of the heat transfer fluid and heat transfer system. 


  • Oil samples taken from plant component  in which are no circulation or in which are sludge, coal particle or other particle have been deposited. In this way the analysis can disclose greatly inflated  carbon values. In the reverse case the analyzed oil can also be considerably less charged, because it was not in circulation. Then the analysis would disclose potentially too high flash points.

  • If oil samples are not cooled sufficiently before removal there can readily volatile components evaporate and the analysis shows, for example, a high flash point. This may lead to dangers posed by a low flash point which are not recognized and so for example cause a fire.

  • Hot oil samples may come in contact with atmospheric oxygen whereby oxidation occurs and cause organic acids in the oil. Again the assessment of adulterated oil samples lead to false conclusions.

  • Hot oil samples are taken with inappropriate sampling containers which react, for example, with the sample liquid or contain traces of water or other substances, which also leads to incorrect analysis results.


Alalysis according to DIN 4754 or rather DIN 51529 – Why?

Thermal oil systems in view of a fire are subject to monitoring. To control the system includes a thorough analysis of the heat transfer oils. This analysis must take place at least once a year. So prescribes DIN 4754 before.

In essence, the oil analysis is performed to assess or rather to early detect abnormal values, for example, neutralization number, viscosity, water content, flash point, ect. The annual oil analysis can not prevent malfunction, incorrect operations or defective equipment during the year to disrupt or even interruptions of course. In addition, damaged heat transfer media often cause increased operating costs, due to unnecessarily high pump power or thermal oil deposits in the system, thereby unnecessarily high temperatures must be driven at higher fuel consumption. To detect changes of the heat carrier at any time and at an early stage, Maxxtec offers a media monitoring system which is capable of the state of organic heat transfer media continuously and online monitoring. When values are exceeded, the operator is informed early and can initiate timely countermeasures to avoid unplanned shutdowns. This on-line monitoring system can be integrated with regeneration facilities so that in case of deviations of allowed values of solid particles or low boiling components can be automatically removed from the system until the permissible parameters are met again.


Reduce costs

With optimal plant design and prescribed equipment maintenance thermal oils can often be used for decades. To allow such lifetimes, negative influences must be detected and eliminated early. This based on true and accurate analysis and expert assessment of results. In this way, expensive oil change or even serious damage to the system can be reliably avoided.

Analysis of heat transfer oils are only as meaningful as the oil sample itself. Because of adulterated oil samples and resulting misjudgments it always comes back to avoidable premature oil changes.

A clean and representative analysis of the thermal oil is not only annoying rule, they also help, to reduce costs and ensure safe operation.


Advantages of the sample cooler at a glance


  • avoid unnecessary oil changes
  • lower replenishment
  • longer life of the heat carrier oils
  • less downtime because impurities can be detected early and purification can occur early, during the plant operation
  • increase energy efficiency by using less fuel and electricity demand
  • reduced fire risk
  • reduced risk of sedimentation


Technical data:

Connection nominal diameter: 10 mm
Allowable operating pressure: 16 bar
Housing dimensions: 514 x 168,3 mm
Operating temperature: 350 °C
Net weight: 74 kg


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