pH/ORP (REDOX)-Universalsensor FU20/FU24/PH20

Die Universalsensoren PH20, FU20 und FU24 zeigen, wie Yokogawa das Motto „einfach ist am besten“ auf Sensortechnologie anwendet. Diese Sensoren verfügen über vier separate Elemente (pH- und Redoxelektrode, Referenzelektrode, Temperatursensor), was die gleichzeitige Messung von pH und ORP (Redox) mit einem einzigen Sensor in einem robusten Gehäuse aus Ryton oder PVDF (FU20), Ryton (FU24) oder PVDF (PH20) ermöglicht. Das integrierte oder Variopin-Kabel mit Nummerncode macht zusammen mit den integrierten NPT-Gewinden am Sensor die Installation sehr einfach. Die Schnellwechseladapter für den FU20 ermöglichen eine schnelle Entnahme des Sensors zur Reinigung und Kalibrierung.

Welcher Sensor ist der Richtige für Sie?

Es gibt nun FÜNF unterschiedlich Großraumsensorausführungen zur Auswahl. 

Verwenden Sie bitte die Diagramme unten als Anleitung zur korrekten Auswahl der am besten für Ihre Anwendung geeigneten Version.

  • Verfügbar als analoge Sensoren und digitale SMART-Sensoren (SENCOM)
  • Massive Platin-ORP/LE-Elektrode für genaue und gleichzeitige pH- und ORP-Messungen.
  • Integrierter Pt1000-Temperatursensor für präzise Temperaturmessungen und größere pH-Genauigkeit
  • Doppeldiaphragma und langer Diffusionspfad zur Vermeidung von Kontamination/Vergiftung der Referenzelektrode
  • Das gesättigte Ag/AgCl-Referenzsystem mit Doppeldiaphragma verlängert in Kombination mit polymerisiertem gesättigtem KCl und Ionenfalle die Lebensdauer der Referenzelektrode auch in chemisch problematischen Umgebungen.
  • Erhöhte Lebensdauer durch ein großes Volumen polymerisierten Elektrolyts und poröses PTFE-Diaphragma
  • Kationdifferenz-Referenzsystem für eine längere Lebensdauer für den FU20 erhältlich
  • Variopin-Anschluss oder integrierte Kabeloptionen
  • Einfache Wartung durch einen übersichtlichen Aufbau
  • Vielseitige direkte Inline-, Eintauch- oder Offline-Installation (Durchflussarmatur) und auswechselbarer Hochtemperaturteil (nur für Verwendung mit dem FU20 verfügbar)
  • Schnellwechseladapter für den FU20 lieferbar
  • Ein Kalibrierzertifikat liegt jedem Sensor bei
  • Patentierter Druckausgleich in PH20 und FU24
  • Lieferbar in zwei Versionen, einem Modell mit robuster kuppelförmiger Elektrode für Medien mit geringem Feststoffgehalt und einem Modell mit flacher Elektrode für Anwendungen mit erheblichem Feststoffanteil

Der Kombisensor FU20 zeigt, wie Yokogawa das Motto „einfach ist am besten“ auf Sensortechnologie anwendet. Die Großraumsensoren (26 mm Durchmesser) enthalten vier separate Elemente in einem unzerbrechlichen PPS40GF (RytonTM)- oder PVDF-Gehäuse. Die Installation gestaltet sich mit dem integrierten industriellen 3/4“-Kegelgewinde sehr einfach. Das große Volumen an geliertem Elektrolyt und das Doppeldiaphragma-Referenzsystem verlangsamen den Elektrolytverbrauch und die Vergiftung des Referenzsystems und verlängern so dessen Lebensdauer. Das System ist auf solche Anwendungen zugeschnitten, bei denen sich Einfachheit in genauen und zuverlässigen pH- oder Redoxmessungen niederschlägt. Dies bedeutet, dass dieser Sensor in 90 % der Fälle eine hervorragende Wahl darstellt.

Der FU24 ist ein pH- und ORP-Universalsensor mit chemisch beständigem PPS 40GF-Gehäuse für anspruchsvolle pH-Messanwendungen. Er ist besonders nützlich in Anwendungen mit Fluktuationen von Druck und/oder Temperatur. Diese Prozessbedingungen verkürzen die Sensorlebensdauer, weil die Prozessflüssigkeiten durch häufige Druck- und/oder Temperaturschwankungen in den Sensor hinein- und wieder herausströmen. Dies führt zu einer schnellen Entsalzung und Verdünnung des Referenzelektrolyten, was seinerseits eine Änderung der Referenzspannung und somit Abweichungen bei der pH-Messung zur Folge hat.

Durch Integration des erfolgreichen und von Yokogawa patentierten Balgkonzepts in die FU24-Elektrode wird eine wirkungsvolle Druckkompensation erreicht. Der in die Elektrode integrierte Faltenbalg sorgt für einen sofortigen Ausgleich zwischen Innen- und Außendruck und macht den Sensor praktisch unempfindlich gegenüber externen Druckschwankungen. Ein leichter, von der Balgspannung verursachter Überdruck verhindert das Eindringen von Flüssigkeit und sorgt für einen Ionenfluss aus dem Sensor.

Der PH20 trägt den englischen Spitznamen „Tempress“ wegen seiner patentierten Kompensation von Temperatur- und Druckänderungen („pressure“). Diese einfache mechanische Lösung macht den Sensor genauer und verleiht ihm gleichzeitig eine längere Lebensdauer. Die Ausgleichselemente verformen sich, um Änderungen zu kompensieren und so große Druckdifferenzen über das Diaphragma zu vermeiden. Dies beugt den meisten Problemen mit der Referenzmembran vor. Der PH20 ist aus chemisch beständigem PVDF gefertigt. Das Referenzsystem besteht aus Silber/Silberchlorid mit einem Doppeldiaphragma und einem gelierten Elektrolyt gegen Verschmutzung. Die Platin-Redoxelektrode dient gleichzeitig als Flüssigkeitserde, was für kompromisslose Genauigkeit und Sensordiagnosemessungen von entscheidender Bedeutung ist.

Hochtemperaturhalterung PR10

Online-Messungen stellen oft eine besondere Herausforderung dar, insbesondere wenn Routinewartung erforderlich ist. Die PR10 ist ideal geeignet für Anwendungen, bei denen die Sensoren entfernt werden müssen, ohne den Prozess zu unterbrechen oder abzustellen. Ohne irgendwelche Spezialwerkzeuge kann die PR10 bei Drücken von bis zu 5 bar (72 psi) sicher aus dem Prozess gezogen werden. Mit der PR10 kann jeder beliebige Gelöstsauerstoffsensor mit PG13.5-Anschluss in eine Wechselarmatur eingesetzt werden.

Durchfluss/NPT-Armaturen FF20/FS20

Yokogawa hat viel Aufwand und Zeit in die Entwicklung einer breiten Palette von Armaturen investiert. Ein besonderer Schwerpunkt lag dabei auf der Senkung von Installations- und Wartungskosten und somit günstigeren Betriebskosten.

WU10 Kabel

Universelles Sensorkabel zur zuverlässigen Übertragung analoger Signale, das speziell für die Installation in Schwerindustrieumgebungen konzipiert wurde.

Übersicht:

Wet scrubbers are used in utilities, paper mills, and chemical plants to remove sulfur dioxide (SO2) and other pollutants from gas streams. Undesirable pollutants are removed by contacting the gases with an aqueous solution or slurry containing a sorbent. The most common sorbents are lime, Ca(OH)2, and limestone, CaCO3

Industrien:
Applikations-beschreibungen
Übersicht:

For control of batch neutralization, a pH measurement coupled with a timer-controlled chemical feed scheme provides very satisfactory results.

This system can be adapted for either acid waste or alkaline waste neutralization.

Applikations-beschreibungen
Übersicht:

The term "cooling tower" is used to describe both direct (open circuit) and indirect (closed circuit) heat rejection equipment. Cooling towers are heat-transfer units, used to remove heat from any water-cooled system. The cooled water is then re-circulated (and thus, recycled) back into the system. Since the process water is re-circulated, the mineral concentration increases as a result of the evaporation.

Industry:Refining, Food and Beverage, Power, Oil and Gas, Pulp and Paper, Chemical

Industrien:
Applikations-beschreibungen
Übersicht:

There are a number of suppliers of oil and fat products used for edible purposes. These products include, but are not limited to olive oil, peanut oil, soybean oil, sunflower oil, lard, shortening, butter, and margarine. The raw materials for these products include animal by-products, fleshy fruits (palm and olive), and oilseeds. 

Industry:Food and Beverage

Applikations-beschreibungen
Übersicht:

Process liquid analyzers such as pH meters, conductivity meters, ORP meters, and density meters play an important role at electrolysis plants in the control of concentrations of various process solutions. This requires both precision and stability under harsh conditions that include highly corrosive substances, high temperatures, and many impurities.

Übersicht:

Most zinc are produced at hydrometallurgically, where a high-grade zinc product can be obtained and valuable metals mixed in the raw material can be recovered. In the hydrometallurgy, the raw material of zinc concentrate is roasted and then dissolved in sulfuric acid to remove impurities. The process called leaching and pH control of the leachate is important.

Industry:Chemical, Power

Industrien:
Übersicht:

Cyanide-bearing wastewater from mining and electroplating facilities and certain types of chemical plants is toxic and must be treated by oxidation with chlorine or chloride to bring the cyanide concentration within regulatory limits.

Industry:Electrical and Electronics

Applikations-beschreibungen
Übersicht:

Introduction

The Combined Effects of pH and Percent Methanol on the HPLC Separation of Benzoic Acid and Phenol:

Many mobile-phase variables can affect an HPLC (High Performance Liquid Chromatograph) separation. Among these are pH and the percent and type of organic modifier. The pKa of a weak acid is the pH at which the acid is equally distributed between its protonated (uncharged) and unprotonated (charged) forms. This is illustrated by the Henderson–Hasselbalch equation:

pH = pKa + log ([A_]/[HA]

where [A_] is the concentration of the weak acid in its unprotonated form
and [HA] is the concentration of the weak acid in its protonated form.
 

If the weak acid is equally distributed between its two forms, ([A_]/[HA]) = 1, log ([A_]/[HA]) = 0, and pH = pKa. If the weak acid is not equally distributed between its two forms, then the pH will be either less or greater than the pKa of the weak acid.

For example, if [A_] < [HA], ([A_]/[HA]) < 1, log ([A_]/[HA]) < 0, and pH < pKa. Thus, a weak acid exists primarily in its protonated form at a pH below the pKa and therefore has a greater affinity for the nonpolar stationary phase. If [A_] > [HA], ([A_]/[HA]) > 1, log ([A_]/[HA]) > 0, and pH > pKa. Thus, a weak acid exists primarily in its unprotonated form at a pH above the pKa and therefore has a greater affinity for the polar mobile phase.

Fig 1 - full-factorial experimental design

Fig. 1 - A three-level, two-factor
full-factorial experimental design

Organic modifiers also have an effect on the retention of solutes in HPLC. In the reversed-phase mode (polar mobile phase, nonpolar stationary phase), the most polar solute component will elute first. This is because the most polar component interacts least with the nonpolar stationary phase.

As the polarity of the mobile phase is increased, those solute components that were previously highly retained (nonpolar components) will be retained even more.

Two species that are of public interest because of their classification as moderate environmental and health hazards are benzoic acid (pKa = 4.202) and phenol (pKa = 9.98). The purpose of this study is to investigate the combined effects of pH and percent methanol on the reversed-phase HPLC separation of these compounds.

A three-level, two-factor fullfactorial experimental design will be used to specify nine mobile phases for consideration in this study. The levels of pH were chosen to bracket the pKa value of benzoic acid (below, near,
and above 4.202). It was not possible to study a mobile phase with a pH > 7.5 owing to the pH range limit of the column. A methanol/water mobile phase was selected for this study because methanol is readily available in most undergraduate labs and relatively inexpensive. In addition, both solutes elute in a relatively short time, making completion of this lab during one or two lab periods possible.

Table 1. Mobile Phases Specified by the Experimental Design
 
Phase No. Methanol % pH
1 25 3.0
2 25 4.5
3 25 6.0
4 50 3.0
5 50 4.5
6 50 6.0
7 75 3.0
8 75 4.5
9 75 6.0

Major Observation

At low mobile-phase methanol concentration (25%), as pH increases, the retention time of phenol appears to be unaffected, whereas the retention time of benzoic acid decreases significantly. Over the pH range investigated, the mobile-phase pH is below the pKa of phenol. Thus, phenol will remain in its protonated form and should be unaffected by these mobile-phase changes. However, as pH increases, benzoic acid shifts from its protonated to its unprotonated form, decreasing its affinity for the nonpolar stationary phase and decreasing its retention time.

At intermediate (50%) and high (75%) mobile-phase methanol concentrations, as pH increases, the retention time of phenol remains unaffected by increases in pH while the retention time of benzoic acid decreases. This is consistent with the behaviour at low methanol concentration.

At pH 3.0, as percent methanol increases, the retention times of both phenol and benzoic acid decrease significantly. Because both solutes are polar, increasing mobile-phase polarity causes both to be retained less tightly. At pH 4.5 (slightly above the pKa of benzoic acid) and pH 6.0 (well above the pKa of benzoic acid) as percent methanol increases, the retention times of phenol and benzoic acid decrease. This is consistent with the retention behaviour at pH 3.0.

Typical Process Details

  • Customer plant: Bulk drug plant
  • Application: This is 4 cycle application. There will 
be a pipe connected to inlet which allows process to flow through the column and the same will be sent out from another pipe at outlet.
  • pH measurement is typically required at both the inlet and outlet. Temp: 30-40°C. pH range shall be 7 to 7.5. Between this range the customer can take necessary action to control his process.
  • Conductivity max. 300 micro siemens/cm.
  • Cycle 1: Process contains 95% liquid methanol, 
2% liquid ammonia, 3% water.
  • Cycle 2: Process contains 30% liquid methanol, 
70% water.
  • Cycle 3: Process contains 90% liquid methanol, 
5% liquid ammonia, 3% water, 2% sugar content.
  • Cycle 4: The column will be cleaned by flushing 
with DM water.
Übersicht:

Wastewater from electroplating facilities and certain types of chemical plants contains toxic forms of hexavalent chromium such as chromate and dichromate. The hexavalent chromium in this wastewater must be reduced before the water can be discharged. This requires a two-step process: hexavalent chromium (CR6) is reduced to trivalent chromium (CR3); and CR3 is precipitated as chromium hydroxide.

Industry:Electrical and Electronics

Applikations-beschreibungen
Übersicht:

Removal of free oil and grease from a wastewater stream reduces the potential for equipment problems to occur further downstream. There are three forms of oil encountered in wastewater treatment at a refinery. 

Industrien:
Applikations-beschreibungen
Übersicht:

Power plant boiler houses designed to burn coal or high sulfur oil are required by Federal and State pollution regulations to "scrub" (remove) sulfur dioxide from flue gasses to meet emission limits. SO2 in flue gasses is known to be harmful to the environment, as it is one contributor to the formation of acid rain. pH control is critical for the proper functioning of the scrubber system.

Industrien:
Applikations-beschreibungen
Übersicht:

Background Information

The core of the activated sludge process is primarily dependent on the control of the aeration basin. The most essential component of any activated sludge plant is the biomass, anaerobic and aerobic bacteria, that attaches themselves to the waste, and digest the waste resulting in relatively clean water as the by-product.

There are several types of bugs that are responsible for different duties. There are the carbon eaters (carbonaceous) and chemical eaters like ammonia (nitrogenous). Just like any other living organism they need certain conditions in order to sustain life and reproduce.

basin1

Introduction

Many components in a process must be in balance in order to obtain complete synergy; example biomass blends, air, return activated sludge (RAS), waste activated sludge (WAS) and throughput. The aeration basin is a holding and/or treatment pond that everything cycles through. It is essential to monitor and control several factors that can influence the efficiency of the biological conditions in the basin; for example:

Temperature: Normally the temperature will be between 10- 40°C. Most biomass bugs achieve optimum efficiency in this range. Increasing or decreasing the temperature can result in the increasing or decreasing the rate at which the bugs eat and reproduce. Along with this all chemical reactions that are taking place at the same time are affected by the process temperature as well.

pH: For most systems the pH should be kept between 6.5 to 8.5 pH, when the pH is too high or too low, the biomass losses the ability to convert the food to energy and raw materials. A pH below 6.5 may cause the growth of fungi and fungal bulking, and will have to be adjusted using a caustic, lime or magnesium hydroxide.

Low Nutrients: If nitrogen and phosphorus are not presented in sufficient amount it can limit the growth rate of the biomass. A sign of nutrient deficiency includes foam on the aeration basin.

Dissolved Oxygen: DO is one of the most critical points of measurement; for most processes the target concentration will be between 1-3 mg/L. The concentration amount is an indication of the basin environment; whether it is in denitrification (excess nitrate, NO3) or nitrification (excess ammonium, NH4) environment. Essentially the DO measurement is set to a level to minimize the ammonium breakthrough. It is not uncommon to see NH4 and DO measurements together.

The DO measurement should be maintained at the point of greatest oxygen demand in the system. Normally this is near the intake portion of the aeration basin, because when the process is in the secondary clarifier no oxygen is added and the biomass bugs are starved of oxygen. When the process is returned to the aeration basin via the RAS pumps the biomass is returned to an oxygen rich area and the bug consume vast amounts of oxygen right away.

Septicity/Toxicity: Septic wastes contain elevated amounts of sulfides and organic acids (such as acetic acid).Other organic materials and heavy metals are also toxic to the biomass, reducing their efficiency or even destroying them.

basin2

Summary

Having too much oxygen in the process is not a problem for the biological system; however the cost for generating the oxygen is one of the largest expenses. By obtaining a good representative average of the dissolved oxygen present in the basin could save the plant large amounts of money. For this reason multiple measurements points are sometimes put into place.

Industrien:
Applikations-beschreibungen
Übersicht:

Fish perform all their bodily functions in water. Because fish are totally dependent upon water to breathe, feed and grow, excrete wastes, maintain a salt balance, and reproduce, understanding the physical and chemical qualities of water is critical to successful aquaculture. To a great extent water determines the success or failure of an aquaculture operation.

Übersicht:

Current trend for increasing mercury awareness throughout the public sector has caused the government to take action. Recently, the Environmental Protection Agency (EPA) has focused their efforts on controlling mercury levels produced in various coal fired power plants. Based on information from several case studies, the EPA developed the Mercury and Air Toxics Standards to cut back mercury emissions. The most popular technology utilized by coal plants to meet the new standards is a scrubber which cleans the off gas from the combustion process. ORP sensors can further monitor the effluent from these scrubbers to ensure optimal mercury emission levels are achieved. By closely monitoring the mercury concentrations in the effluent, plant managers will be able to easily confirm their plants are meeting the EPA's standards.

Industrien:
Übersicht:

The lifetime of a pH sensor has a significant impact on the overall annual costs of a pH measuring loop. Optimizing four key factors will decrease these costs and optimize process control and overall plant efficiency.

Produktvideos

    Übersicht:

    The FU24 is an all-on-one pH and ORP sensor made with a chemical resistant PPS 40GF body for harsh pH applications. It is particularly useful in applications with fluctuating pressure and/or temperature. These processes shorten sensor life because the process fluids move in and out of the sensor under influence of frequent pressure and/or temperature fluctuations. This results in fast desalting and dilution of the reference electrolyte which in turn changes the reference voltage causing a drifting pH measurement.

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