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CaprolactamMeasure concentration precisely
for optimal product quality

Maintenance-free ultrasonic sensors for inline monitoring of your caprolactam production.

Maximize process efficiency and product quality through continuous real-time data.

±0.05% accuracy

Real-time measurement

Maintenance-free

Cost-saving

Why is caprolactam measurement a special challenge?

Fluctuating concentrations directly affect product quality. For example, the production of high-quality polyamide 6 (nylon) requires precise control of caprolactam concentration - often in complex, multi-stage processes with extreme conditions.

Typical challenges

  - Extreme temperatures up to 150 °C in distillation columns

  - Aggressive media  such as H2SO4, oleum, ammonium sulfate solutions

  - Phase separation: Separate caprolactam from ammonium sulfate

  - Fluctuating concentrations  depending on the process step

  - Time-critical processes, which require split-second reactions

Typical quality requirements

 - precise control of caprolactam concentration

  - Residual water content determine

  - Residual monomer minimize

  - Continuous process monitoring


Conventional measurement technology reaches its limits

Laboratory analyses are too slow, optical methods fail when contaminated, and conventional sensors do not withstand extreme conditions.


Discover our solution

Our solution for caprolactam concentration measurements

LiquiSonic® Measurement system

The LiquiSonic® measurement system uses innovative ultrasonic speed measurement for precise, completely maintenance-free inline analysis - even under extreme conditions.

Absolute sound speed measurement

Measurement of ultrasonic speed as a direct physical quantity - independent of turbidity, color, or conductivity of the caprolactam solution.

Inline measurement in real-time

Continuous monitoring directly in the process stream without sampling. Measurements are immediately available for process control.

Robust sensor design

Fully encapsulated design without moving parts or wearing components. Materials such as HC2000 or PFA for aggressive media.

Technical details and specifications

Ultrasonic measuring principle

The LiquiSonic®  system measures the absolute speed of sound of ultrasonic waves in the caprolactam solution. This physical quantity directly correlates with the concentration and is independent of optical properties such as turbidity or color.

  • Precise real-time measurement
  • Independent of turbidity
  • No recalibration required

Economic benefit

Cost savings:

  • Less resource/energy consumption
  • Significantly fewer laboratory analyses
  • No maintenance costs
  • Less waste

Payback:

  • Typical payback period 6-9 months
  • Prevention of costly plant shutdowns

Risk minimization:

  • Continuous quality control
  • Reduction of unplanned downtimes
  • Optimized process management

Technical specifications

Measurement ranges (caprolactam in water)

0 - 60 wt% / 40 - 80 wt% / 60 - 100 wt%

Measurement accuracy

typically ±0.05 wt%

Repeatability

±0.02 m/s

Temperature range

-40 °C to 200 °C

Pressure range

Up to 500 bar

Sensor length

Up to 3000 mm

Material & coating

Stainless steel, Hastelloy, PFA, PVDF, ETFE, ...

Digital transmission

Up to 1,000 m (more on request)

Interfaces

4-20 mA, Profibus, Ethernet, Modbus, Fieldbus, ...

Protection class

IP65 & Ex-Schutz verfügbar

Calibration

One-time factory calibration

Maintenance

Completely maintenance-free

Application examples

The LiquiSonic® System supports you in all critical phases.

Beckmann process

H2SO4 / Oleum concentration measurement

Extraction

CPL concentration in solvent

Phase separation

CPL from ammonium sulfate phase

Distillation

Caprolactam in water

Crystallization monitoring

Ammonium sulfate monitoring

Reactor water

Water in caprolactam


Success stories and references:

Detailed case studies and customer references can be obtained from our sales team. Contact us for specific application examples from your industry.

The main advantages at a glance


Precise real-time measurement

Robust & maintenance-free

Very short payback period

Continuous quality control


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Frequently asked questions

What is SensoTech?

SensoTech GmbH is a leading company in the field of process measurement technology based in Barleben, near Magdeburg, Germany. We develop and produce innovative solutions for monitoring and optimizing industrial processes. Our specialization lies in the precise measurement of concentrations, densities, and other parameters in liquids – in real-time and directly during the process.

What distinguishes LiquiSonic® from conventional measurement technology?

Unlike optical methods, which are affected by color or turbidity, conductivity-based methods, which are sensitive to electrical conductivity, or density-based methods, which can be disturbed by temperature or gas bubbles, our Ultrasonic process independent of these influences.

The LiquiSonic® measuring technology also contains neither moving parts nor components that can wear out or be consumed. Therefore, after installation, the measuring system is completely maintenance-free. and drift-free.

The sensors offer digital signal transmission up to 1000 m and enable continuous inline measurement without sampling.

How is the caprolactam concentration measured accurately?

Our system uses ultrasonic transit time measurement to determine the speed of sound in the liquid. The speed of sound directly correlates with the caprolactam concentration and enables measurement accuracies of ±0.05 wt%. The integrated temperature compensation ensures stable results even with fluctuating process conditions.

Is the system suitable for nylon quality control?

Absolutely. The system monitors critical parameters for PA6 quality: residual monomer content, water content, and impurities. It supports the compliance with ISO standards and enables the continuous documentation for quality certificates. This is particularly important for automotive and textile applications.

Which process conditions can be covered?

Our sensors operate reliably in a temperature range from -40 °C to 200 °C and pressures up to 500 bar. With various material options such as stainless steel, Hastelloy, or PFA coatings, aggressive media can also be measured. Ex protection for Zone 1 and 2 is also available.

Can extreme operating ranges also be covered?

Yes, our sensors are designed for extreme conditions. In addition to the extended temperature and pressure range, we offer custom adaptations such as sensor lengths up to 3000 mm, special alloys for corrosive media, and various protection types, such as optional Ex protection. Each sensor is individually according to your requirements configured.

How is the integration into existing automation systems carried out?

The system offers various digital interfaces (e.g., Profibus, Ethernet/IP, Foundation Fieldbus) as well as analog 4-20 mA outputs. The integration is seamless via standardized protocols.

Is customization for special pipes or containers possible?

Yes, SensoTech manufactures sensors individually according to customer requirements.. All standard flanges, any installation lengths, various threads, and special geometries for crystallization containers or small pipes are available.

What maintenance is required for reliable caprolactam concentration measurement?

The system is completely maintenance-free.. There are no mechanical wear parts, seals, or optical windows that could be affected. Regular calibration is not required - the sensors remain stable for years.

What materials and coatings are available for the sensors?

The sensors are available in  various material- and media-resistant designs,  including stainless steel and Hastelloy as well as chemically resistant coatings and plastics like PFA, PVDF, and ETFE. This allows them to be reliably used in a wide range of liquids and demanding process environments.

How quickly do you get measurement results for caprolactam concentration measurement?

The system provides real-time results. Over 30 measurements per second are conducted. Based on these measurements, you receive an up-to-date measurement value every second.. This fast response time enables effective process control and early detection of deviations.

How does LiquiSonic® respond to temperature fluctuations in concentration measurement?

Since the speed of sound, like all other physical quantities, is affected by temperature, all our LiquiSonic® sensors are equipped with high-precision temperature sensors. This allows the influence of temperature on the measurement to be directly compensated to be directly compensated. Therefore, it is not necessary to integrate additional temperature sensors.

Related Applications


Ethylene Glycol Measurement

Precise inline measurement, for example of ethylene glycol concentrations in cooling systems and chemical processes.

Sulfuric Acid Monitoring

Continuous concentration measurement of H2SO4 in various industrial applications.

Polymerization

Monitoring of polymerization processes and reaction progress, for example in plastic production.

Solvent Recycling

Optimization of solvent recycling processes through precise purity measurement.

Washing Solutions

Monitoring of washing solutions and extraction media in chemical processing.

Caprolactam Production

More about the production of caprolactam and how LiquiSonic® can support the process.