(Deutsch) Messeteilnahme AnugaFoodTec 2018 in Köln

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Pfaudler Messtechnik at the “drinktec” trade fair in Munich

Pfaudler Messtechnik at the “drinktec” trade fair in Munich

This year, the drinktec trade fair drew the largest number of exhibitors ever recorded in its over 60-year history. About 1,600 exhibitors, including Pfaudler Messtechnik, came to Munich to participate in the world’s leading trade fair for the beverage and liquid food industry taking place from September 11 to 15. From family-owned companies to global players, all the big names in the industry were represented at drinktec.

This year, Pfaudler’s Measuring Technology department joined the roster of exhibitors for the first time, showcasing pH measuring probes developed specifically for the food industry. Measuring probe types presented at drinktec included pH Reiner in hygienic design, pH 18 and even entire pH measurement systems for highest hygienic standards.
The modern and eye-catching trade fair booth also drew a lot of attention. In addition to interested users from the German liquid food industry, such as breweries, we also succeeded in establishing new contacts with international customers. All in all, we recorded a high number of project inquiries and held many high-quality discussions.
drinktec also presented a great opportunity for learning more about user experiences, enabling us to use this valuable information in future product developments within the company.
In summary, the trade fair was a great success for us – and with AnugaFoodTec, held in Cologne in March 2018, the next chapter of our success story is already waiting to be written.

Efficient pH measurement technology in flue gas desulphurisation plants

When organic material is burned in power plants or during various procedures of process engineering, noxious gases form that are not permitted to enter the environment without aftertreatment.

The treatments required include extracting the sulphur dioxide that results during the burning process from the flue gas. In larger plants, a wet process (see box) is generally used for this purpose. Having been used for this method since 1978, Pfaudler probes have proven a long-lasting and low-maintenance solution for measuring pH.

The flue gas desulphurisation (FGD) probe’s purpose is to set the optimum pH value of the scrubbing suspension during wet desulphurisation*. A fundamental problem of measuring pH in FGD is that stubborn scale deposits accumulate on the pH probe in just a short time. These deposits lead to impairment or even failure of the pH measurement. Because of this, conventional pH sensors must be removed or cleaned with acid at short intervals, which results in high operating and maintenance costs. When a Pfaudler pH probe is installed, the smooth enamelled surface and robust design prevents scale deposits from accumulating at the recommended inflow velocity of 1.5-2m/s. Some pH probes have been in constant use for over 25 years. The probe usually only needs to be maintained or calibrated when the entire plant is shut down once a year for maintenance.

* The method used most often for the desulphurisation of exhaust gases is the extremely efficient wet scrubbing method, wherein the acidic-in-solution sulphur dioxide is sequestered by an alkaline scrubbing suspension in a scrubbing tower (absorbing tower). Calcium carbonate is usually used for neutralisation here. The calcium sulphite that results from the process is converted into calcium sulphate (gypsum) in the lower part of the absorbing tower by supplying air into it. It is then used as a building material in the construction industry.

Combined pH/ORP measurement in a power plant

Since early 2000, combined pH/ORP (oxidation-reduction potential) probes have been used in FGD plants to monitor the AOX compounds found in the effluent water. This allows both measurements in the washing suspension to be recorded at the same time with just one measurement probe and one transducer. Pfaudler pH probes that are already in place can be replaced easily, since they are mechanically and electrically compatible. Pfaudler pH/ORP ring probes are generally used with a nominal size of DN 50. They are used directly in the pipeline between a flange connection, which prevents the pipeline’s cross-section from narrowing and achieves a lower probe abrasion.

Enamelled ring probes – The facts

  • Consistent measuring accuracy over the entire service life (no ageing)
  • No scale build-up thanks to smooth enamelled surfaces
  • Minimal maintenance due to lack of cleaning/calibration processes
  • No retractable assembly required
  • Robust against mechanical impacts
  • Extremely resistant to corrosion
  • Resistant to pressure pulses
  • Shock-resistant to ∆T at max. 120°C
  • Can be used with high flow rates
  • Can be stored dry for any length of time
  • Simultaneous measurement of pH and ORP values

Operating instructions for the Pfaudler ring-probe type 03

Reliable corrosion monitoring – now available for Cryo-Lock agitators

Continuos Corrosion monitoring for Cryo-Lock agitators

Continuous monitoring of the glass lining inside a vessel during operation is indispensable in highly corrosive processes, in order to rule out large and costly tantalum repairs or even rupture of vessels. A corrosion detection system is the solution. Where multi-piece glass-lined agitators are used, it has never before been possible to monitor the entire agitator assembly. The use of the Corrosion Detector in conjunction with Pfaulder’s new Conductive Cryo-Lock technology has now made this possible.

The moving parts in a reactor are most prone to damage, but can now be monitored for integrity with Pfaudler’s new Conductive Cryo-Lock technology. This continuous in-process glass lining monitoring system is suitable for all Pfaudler Cryo-Lock agitators.

The Pfaudler glass lining monitoring works based on the principle of decomposition voltage analysis, which eliminates the need for a continuous current load on the precious metal electrodes and thus prevents electrochemical reactions on the electrodes. A voltage is applied periodically between the two electrodes and used as a reference to generate an “alarm window”. If the measured value is repeatedly within this alarm window due to a damaged glass layer, the Corrosion Detector will output an alarm. Pfaudler has offered this technology for years as a reliable way to monitor the glass lining of vessels, but it was impossible to monitor multi-piece agitators completely. A non-metallic inductive contact between the turbine and the agitator shaft has now solved the problem. In contrast to solutions with welded-on metal rings made from resistant materials, this ensures a completely homogeneous enamel surface. There are no differences in temperature expansion coefficients caused by different materials – another source of inevitable damage to the glass lining is avoided. Pfaudler’s Conductive Cryo-Lock technology thus provides comprehensive vessel monitoring, including the entire multi-piece agitator, for excellent process reliability.

No more false alarms!

The Corrosion Detector will only output an alarm if metal corrosion has actually occurred, so false alarms caused by corrosion-resistant conductive fittings and materials are ruled out. The system tolerates inlet pipes and repair plugs made from precious metals. This method offers fundamental advantages over conventional glass monitoring equipment, which works according to the principle of conductivity analysis. Such systems are not capable of distinguishing between real and false alarms. A false alarm is defined as conductive contact between the product and the equipotential bonding system that is not caused by glass damage. Such links can be the result of production-specific operating conditions, e.g. condensate bridges in the vessel’s gas compartment, or when filling or draining the vessel. Regular false alarms can cause plant operators to respond to real alarms too slowly, or even to ignore them altogether. This is a considerable risk to people and the plant, and leads to significant disruption in the production process. All the Corrosion Detector needs to work is a sufficiently conductive medium.

Corrosion monitoring on the move

Comprising a P probe and its evaluation electronics, the Pfaudler corrosion monitoring system can be installed in baffles, ring probes or valves. A mobile version is available for vessels without integrated corrosion monitoring: the Corrosion Detector Portable. All solutions are ATEX-approved.

Long-lasting and low-maintenance – Glass lined pH probes in the food industry

Glass lined pH probes in the food & beverage industry

The pH value is one of the most important and commonly measured values in many fields of process engineering. The stability of the entire production process can be increased by regulating the pH value in a targeted way. In food production, the pH value is also an important indicator of consistent quality, taste and reproducibility in a product, and a significant variable during and after cleaning of the production facilities. Thanks to their maintenance-free operation and long service lives, robust glass lined pH probes are a cost-effective option for constant use in the food industry.

The use of glass electrodes has certain disadvantages, such as short calibration intervals, drifting, high vulnerability during CIP and short service lives. Even the most up-to-date transmitters cannot fully compensate these disadvantages. Moreover, pH probes are subject to various mechanical stresses: flow rates and turbulences, pressures and pressure shocks, abrasion and contamination. Glass lined pH probes meet the mechanical requirements and ensure safe and cost-effective production.

The glass lined pH probe comprises a steel probe body with a highly-resistant, anti-adhesive technical glass lining to protect the surface in contact with the product. This makes the probe resistant to mechanical strain by flows, pressure, abrasion and vibrations. Probes can therefore be installed in piping and vessels where they are directly exposed to the flow, enabling direct continuous online measurement in the main product stream. Moreover, the smooth surface the glass lining gives the probe protects it against corrosion and product build-up. Combined with a pressurised electrolyte system, these properties allow the probe to be installed in any position and direction, so the pH sensor can be installed directly at the point of use. Reliable prevention of broken glass in the product is another vital consideration when glass lined pH measurement probes are used in food production.

The pH measurement principle

pH determination is a potentiometric (electrochemical) analysis method. A typical measuring setup comprises two electrodes, a measuring electrode immersed in a process medium and a reference electrode immersed in an electrolyte liquid. The measuring electrode generates a potential that clearly identifies the chemical condition (hydrogen ion concentration) of the medium to be measured.

No ageing

The measuring electrode is fused with an insulated layer of ion-sensitive glass lining and directly connected to the metallic potential discharge line. Unlike in glass electrodes, there is no internal buffer (discharge electrode). In contrast to conventional glass electrodes, the ion-sensitive glass area is only in contact with the process medium on one side. This prevents ageing and drift of the pH sensor.

For absolute pH measurement, the reference electrode is installed either in the electrolyte vessel or in the sensor, depending on the sensor type. In all absolute measurement probes, the electrolytic connection between the reference electrode and the product to be measured is made through a ground-joint diaphragm. The electrolyte is in a separate, insulated pressure vessel connected to the sensor by a plastic hose.

The internal pressure of the electrolyte system is higher than the operating pressure to prevent the measured medium from penetrating the diaphragm zone. This means that the reference electrode cannot be poisoned, making the pH measurement significantly more reliable and increasing the probe’s service life. All Pfaudler pH probes use automatic temperature compensation of the measured value, with an integrated Pt-100 or Pt-1000 measuring the temperature.

Simple design of differential probes

Differential pH probes provide values measured against a product-dependent reference parameter. The measured value is therefore a product-specific value (relative pH measurement) that allows a statement as to whether a process is performed according to defined specifications. This measured value is therefore ideal for controlling and monitoring recurring batch processes (e.g. formulations without changes) or continuous measurement in fermentation tanks, wort boilers, waste water treatment or monitoring of filling plants.

Differential pH probes are simple in structure: two ion-sensitive enamels are fused onto a steel probe carrier and form the measuring part of the sensor. One sensor surface responds to H+ ions and provides a potential that depends only on the pH value; this is called the pH glass. The other sensor surface – the reference glass or reference electrode – responds to the salts dissolved in the liquid, especially the Na ions present, and thus provides a product-specific reference potential.

Once the transmitter has been configured with data from the measurement and test report provided, the pH differential probe is calibrated in its installed position using a product sample. The probe then works like a “normal” pH measurement device in the specified range. The special relative measurement principle means that the probe functions without an electrolytic liquid. This eliminates the risk of the product being contaminated by the electrolyte and ensures practically maintenance-free operation (no refilling of electrolyte).

Easy to clean

pH measurement methods using glass electrodes require the electrodes to be removed from the process for CIP or periodic calibration – often requiring the use of sophisticated and expensive retractable assemblies. Thanks to their smooth surface, glass lined pH probes are easy to clean and can remain in the plant for CIP and SIP. A chemical attack rarely occurs in such cleaning processes. The following CIP procedures are permitted for glass lined measuring probes:

  • 5 to 2 % sodium hydroxide (NaOH), max. 85°C, max. 1 h
  • 5 to 2 % nitric acid (HN03), max. 60°C, max. 15 min
  • 5 to 2 % phosphoric acid(H3P04), max. 85°C, max. 1 h
  • Steam at 134°C, max. 2 h

Depending on the CIP method used, it can take a few minutes or even several hours to compensate for the offset caused by cleaning. This compensation period can be shortened to less than 10 minutes if the glass lined sensor is regenerated with hot water or steam (> 80°C). In contrast, conventional glass electrodes usually need to be recalibrated after each sterilisation process, and replaced after a number of cycles.

If these specifications are observed, a service life of more than 1000 CIP processes is possible in normal food industry processes. In comparison, glass electrodes achieve 50 CIP processes at most. Moreover, the calibration values (e.g. gradient) of calibrated measuring probes remain constant over the entire lifetime, i.e. the probe does not age. Regular re-calibration is therefore unnecessary. The result is significantly higher plant availability, and therefore enhanced productivity and cost-effectiveness.

Dry storage possible

Glass probes normally have to be kept from drying out, because this would damage them. As a result, care must be taken to prevent the glass probe from running dry during the production process or after CIP cleaning. Glass lined measurement probes can be stored dry for any length of time without problems. Once dried, the pH probe merely needs a certain recovery time before the sensitive glass layer can perform stable measurement again.

Glass lined probes – The facts

  • Can be cleaned/sterilised while mounted (CIP/SIP capable)
  • Hygienic design (EHEDG approved)
  • Constant measuring accuracy over the entire service life
  • Very low maintenance costs,as practically no need for calibration
  • No retractable assembly required
  • Protected against glass breakage in product
  • No product build-up thanks to smooth glass lined surfaces
  • Robust against mechanical impacts
  • Resistant to acids and organic solvents
  • Not sensitive to oils and greases
  • Resistant to pressure pulses
  • No hysteresis during temperature changes
  • Shockproof up to 1H at max. 120°C
  • Can be used with high flow rates
  • Can be stored dry for any length of time