Lab instruments for oil and gas. Made in Germany.

Differential Dynamic Scale Loop

Examination of Scale Formation in Pipelines

The Differential Dynamic Scale Loop (DSL) by PSL Systemtechnik as a fully automated laboratory device is a tube blocking system to examine the precipitation and deposition of scale and other salt crystals in pipework systems like oil or water pipelines.



  • Small sample volumes
  • Automated tests with decreasing inhibitor concentrations
  • Automated scale detection and cleaning procedure
  • Exchangeable model pipeline
  • Overnight runs possible
  • Up to 380 bar (5500 psi)


  • Observation of crystalline deposits like salts or scale in oil or water pipelines
  • Developement of inhibitors
  • Testing of oil or water treatment additives (Inhibitors / Dissolvers)
  • Quality control


Field of Application

If fluids containing water are pumped through a pipeline, or if sea water or reservoir water are back-pressed, barium sulphate or other salts (scale) can form, especially when salt water and reservoir water are mixing. These hardly soluble substances deposit to the inner wall of the pipeline and can plug the line or the pores in the sediment.

Originally, the Differential Dynamic Scale Loop was developed for applications in the petrochemical and oil industry as tube blocking system. However, to keep pipelines clear of deposits is also essential for many industrial processes where water pipelines play an important role, for example in mining, paper manufacture, desalination or in various other areas where a reliable water supply, e.g. with cooling water, has to be ensured. Many products (additives) for these industries like inhibitors and threshold inhibitors for water treatment can be tested with the laboratroy instrument Differential Dynamic Scale Loop.


Measuring Principle of Differential Dynamic Scale Loop

The  Differential Dynamic Scale Loop was particularly developed to observe this deposit-forming processes under realistic conditions and to design counteractive measures. This is carried out in three steps:

  1. Determine the risk of sedimentations
  2. Selection or development of an inhibitor
  3. Test the efficiency of the inhibitor and determine the minimal neccessary inhibitor concentration

To execute this process three HPLC-pumps are used in the Differential Dynamic Scale Loop. Two solutions (anionic and cationic) are mixed with a third fluid which contains a known concentration of inhibitor. The mixed solutions are pumped throug a model pipeline. The inhibitor concentration is automatically reduced stepwise, by an increase of pressure (measuring of differential pressure) the start of sedimentation is indicated (tube blocking).

The model pipeline can be exchanged and is available with different length and inner diameters to simulate different test conditions.

For the Differential Dynamic Scale Loop is a sample volume of 500 ml already sufficient for a measurement. To simulate different environment conditions, measurements can be executed with temperatures up to 300 °C (572 °F) with a high accuracy and model-specific pressures up to 380 bar (5.500 psi)

The software convinces!

Complex test and fully automatic cleaning procedure

The software of Differential Dynamic Scale Loop WinDSL permits planning and execution of fully automated complex test schedules in steps with different inhibitor concentrations.

With the software of Differential Dynamic Scale Loop a fully automated cleaning with two different cleaning solutions after every test is preset. A precleaning removes remains of the test solutions, a cleaning agent solutes the precipitated scale and a post cleaning prepares the system for the next measurement. So in general you do not have to exchange the model pipeline.

The high grade of automation allows unsupervised overnight runs and long-term experiments.

High-quality materials for a long lifespan

A long lifespan and durability of the Differential Dynamic Scale Loop is achieved by using Monel® for all parts exposed to heat except model pipeline. This is by default made of stainless steel simulating pipeline conditions. On request model pipelines made of other materials, e.g. copper, can be provided. 

The Differential Dynamic Scale Loop can be adapted or extended to your requirements.

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