pH Measurements in the Dye Synthesis of Azo Dyes with the Ceramat Fitting from Knick

In terms of numbers, azo dyes are the largest group of synthetic dyes. They are used as food dyes, paint dyes, primary colors for 4-color printing (yellow and magenta), and on a massive scale, as textile dyes. Worldwide, more than 350,000 tons of azo dyes are used in dyeing natural fibers alone.

Key Facts About the Application

Application

cCare – fully automated sensor maintenance for dye synthesis in which almost all key reaction steps are pH-dependent. Therefore, the optimization of the product yield is based on reliable, low-maintenance pH measurement.

Sector

Azo dye production 24/7

Main Requirements

The measuring loop is subject to the following extreme conditions:

pH = 1, contains hydrochloric acid
Temperature = 90 °C,
Pressure = 6 bar.
pH electrodes have a service life of 8 h to several weeks.

Measuring Parameters

pH

Measuring Technology Requirements

Dye synthesis in modern plants runs 24/7 in four shifts. Almost all key reaction steps are pH-dependent and therefore the yield optimization of the product depends on reliable, minimally maintenance-intensive pH measurement. Diazotization is highly hydrochloric and accordingly, corrosive. The reactors are lined with protective enamel and the coupling reactors are rubberized. The extreme conditions for the measuring loop are pH = 1

Temperature = 90 °C,
Pressure = 6 bar.

The service life of the pH electrodes is 8 h to several weeks. Until now, these measuring loops have been automated with conventional retractable fittings made of Hastelloy C4, but the maintenance costs for these very expensive fittings are high. The fitting must be removed and maintained several times a year.

Our Solution

In conjunction with the Unical 9000 automatic cleaning and calibration system, the Ceramat WA 150 retractable fitting enables full automation of this difficult measuring loop for maximum availability. The Ceramat retractable fitting consists of a practical corrosion-proof, ultra-hard highly polished, rotating ceramic and a stationary molded enclosure made of PEEK that is also corrosion-proof and carbon-reinforced. Even after 24 months of operation, Ceramat shows no wear on seals or other parts.

Why Knick?
Even after 24 months of operation, Ceramat shows no wear on seals, the probe housing, or other parts.

Associated Products

WA150 Ceramat Retractable Fitting | Ceramic lock-gate sealing | Pneumatic | Carbon-fiber-reinforced PVDF or PEEK

Product number:

WA150

Approvals: ATEX

Explosion protection: Yes

Operation: for cCare

Associated Industries and Applications

Chemistry

The chemicals industry is characterized by an extremely wide variety of applications, often in toxic and explosive environments.

Pulp and Paper Production

Many measuring loops in pulp production are located in environments in which technical personnel must spend as little time as possible.

Cooling Tower Monitoring

In a wide range of industrial sectors, cooling towers are used to dissipate process heat from cooling circuits. Mineral deposits and corrosion reduce their efficiency and lead to premature wear on plant parts.

Breakthrough Detection for Heat Exchangers

Heat exchangers are used when liquid process media need to be cooled and/or dissipated heat needs to be recovered for other processes.

Download now

Overview of specific applications and product solutions in different areas of industrial chemicals.

Latest Blog Post

Audit Trail and Remote Login with Protos II via fieldbus

Nov 2025

Process Analytics

Pharma, Protos II 4400, Launch

Fulfill audit trail requirements via fieldbus - Fully automated down to the field level

Knick's Protos II transmitter is now the first industrial transmitter to meet audit trail requirements directly via a fieldbus connection. No additional software or storage media are required for this.

Oct 2025

Company

|

Process Analytics

Local expertise for process analytics directly on site

We are now able to provide our process analytics expertise in even more countries, offering you personal support directly on site

May 2025

Company

|

Process Analytics

Switzerland

Knick Roadshow 2025 – A Huge Success Across Switzerland

Bringing innovation to life, promoting dialogue, sharing knowledge, and strengthening networks

SE605H conductivity sensor with CondCheck: Integrated sockets for connecting a resistance decade

Mar 2025

Process Analytics

Pharma, Sensor, Conductivity

SE605H Conductivity Sensor with CondCheck

The SE605H conductivity sensor with CondCheck enables USP 645 verification without interrupting the measuring chain.

Optical probe from Hellma and retractable fittings from Knick

Jul 2024

Process Analytics

Achema, Fitting

Hellma Spectroscopy Probes and Knick Retractable Fittings

A strong team for more efficiency and safety in production and manufacturing processes with spectroscopy analytics

Knick’s large, international team at its ACHEMA 2024 trade fair booth.

Jul 2024

Process Analytics

Achema

ACHEMA 2024 - Review and Impressions

A brief cinematic retrospective of our trade fair booth, Knick’s international team, and a successful booth party.

Feb 2024

Process Analytics

Launch, Uniclean700

Uniclean 700 Series - Modular control system for automated sensor cleaning

With the Uniclean 700 series, Knick is introducing a modular control system, that can be installed very quickly and cost-effectively as a flexible entry-level solution for automated sensor cleaning.

Dec 2023

Company

|

Process Analytics

|

Interface Technology

Knick Austria - direct customer contact in Austria from 2024

Reorganization of sales in Austria and new contacts in the field of process analytics and interface technology

Apr 2023

Process Analytics

Fitting, Launch, WA111

Robust WA111 Retractable Fitting Made of Plastic for Highly Corrosive Operating Conditions

The plastic WA111 retractable fitting is a robust and cost-effective solution for corrosive processes and environments. It is equipped with a secure lock function and multiple nozzles for thorough sensor cleaning.

Apr 2023

Process Analytics

Fitting, Launch, WA155

Successful joint project : Knick developed the special Ceramat WA 155 retractable fitting for optical probes from SOPAT

In cooperation with SOPAT, Knick developed a special Ceramat fitting for optical probes for automatic cleaning in fouling processes.

Apr 2023

Process Analytics

Conductivity, Phamacy, pH

pH and conductivity measurement in vaccine production

Pharmaceutical contract manufacturer relies on Knick's transmitters for modular production plants for Covid-19 vaccines.

Apr 2023

Process Analytics

Sensor, Conductivity, SE625

Sturdy 2-Electrodes Conductivity Sensor SE625 with Coaxial Electrodes made of Titanium

The SE625 ensures reliable and accurate determination of the conductivity of ultrapure water in the semiconductor industry.

Jan 2023

Process Analytics

ARD75

Sensor Adapter with Lock Function Enables Safe and Thorough Cleaning

Sensor adapter with locking gate for safety and thorough cleaning of sensors in the immersion fitting ARD75 without the need

Nov 2022

Process Analytics

Protos II 4400, Module

Up to six Sensors on one Transmitter Protos II 4400 via Modul MSU4400-180

Users can now connect up to six Memosens sensors simultaneously.

Aug 2022

Process Analytics

Achema, Exhibition

ACHEMA 2022 - Knick at the world forum for the process industry

In August 2022, the international process industry met at the ACHEMA. Knick presented the cCare system and industrial applications in a new concept.

Jun 2022

Process Analytics

Sensor, pH, SE555, ORP

Combined pH- and ORP-Sensor SE555X/*-AMSN

Combined pH and ORP measurement in one sensor SE555 saves place and equipment costs for demanding requirements in the chemical industry, the food sector and for hygienic applications.

Apr 2022

Process Analytics

MemoTrans

Ultra Compact Transmitter for Memosens Sensors

The new ultra compact MemoTrans MT201 transmitter plugs directly onto the Memosens sensor in the fitting and communicates via 4-20 mA HART protocol.

Feb 2022

Process Analytics

Protos II 4400, Stratos Multi, Software, ProgaLog

Conveniently configure transmitters offline on a PC - ProgaLog 4000

Conveniently configure all flexibly configurable Stratos Multi and Protos II 4400 transmitters offline, save settings, duplicate for further transmitters, and create documentation for audits.

Feb 2022

Process Analytics

Stratos Multi, Transmitter

New Stratos Multi E461N transmitter with Profinet

The interface enables continuous communication of process variables and predictive maintenance from the field level to all common process control systems.

Jan 2022

Process Analytics

Memosens

Memosens 2.0: Evolution of digital data transfer

As one of the two initiators of Memosens, Knick is constantly developing the technology.

Nov 2021

Process Analytics

Sensor, Conductivity, Ex, SE656, SE655

SE655X Digital and SE656X Digital - Digital Conductivity Sensors with Ex Certification

The SE655X digital and SE656X digital conductivity sensors with Memosens protocol are now also available with Ex certification.

Oct 2021

Process Analytics

Stratos Multi, Transmitter, Ex

Stratos Multi E401X- Multiparameter Transmitter for Hazardous Locations

The new Multiparameter Transmitter Stratos Multi E401X can now also be used in hazardous locations, installed in Ex Zone 2.

May 2021

Process Analytics

Transmitters, Stratos Multi

Stratos Multi E471 with EtherNet/IP for process optimization

EtherNet/IP communication protocol allows the transmitter to be easily integrated into Industrial Ethernet networks as PCS.

May 2021

Process Analytics

Sensor, Conductivity, Launch, SE656

New SE656N digital conductivity sensor

New toroidal Digital Conductivity Sensor with a large measuring range and consisting of PFA for using in aggressive media

Mar 2021

Process Analytics

Protos II 4400, Profinet

Transmitter for the process industry with PROFINET module

The PROFINET industrial Ethernet standard is becoming an increasingly important aspect of process engineering in the “Industry 4.0” environment.

Jul 2020

Process Analytics

Fitting, Launch, ARD170

High-quality immersion fitting for mobile applications

ARD 170 enables measurements even in deep water

Jul 2020

Process Analytics

Fitting, ARD50, ARD75

Modular immersion fitting as an electrically conductive variant

Knick is expanding its portfolio of fittings for liquid analysis with additional electrically conductive (EL) variants.

Apr 2020

Process Analytics

Launch, Transmitters, Stratos Multi

New multiparameter transmitter Stratos Multi

Knick is launching the the next generation in its Stratos analyzer product line.

Feb 2018

Process Analytics

Sensor, Fitting

How to get the sensor into the process

Sensors as the direct interface to the process must be exactly matched to the chemistry of the measured medium and to the prevailing pressure and temperature conditions.

Apr 2017

Process Analytics

MemoRail Modbus

Powerful compact analyzer boosts performance while reducing costs

It has long been common practice when taking pH/ORP, conductivity, and oxygen measurements that a fixed analyzer be mounted near the sensor. The analyzer serves several purposes.