PR10 Retractable Assembly

On-line measurements often present extra challenges, especially when routine maintenance is required. The PR10 is ideally suitable for applications where the sensors must be removed without interrupting or shutting down the process. Without any special tools the PR10 can be retracted safely from the process at pressures up to 5 bar (72 psi). The PR10 is a universal retractable assembly that can be used for all liquid measurements. The PR10 is designed to accept any commercially available pH/ORP or dissolved oxygen sensor that has a PG13.5 connection while still being backwards compatible with old Yokogawa electrodes.

For ease of use, optional flush ports are available. In the retracted position the sensor can be kept moist, cleaned or even calibrated. This can all be done without process interruption or disassembly of the armature.

  • One model for pH/ORP, dissolved oxygen, conductivity and inductive conductivity sensors
  • All commercially available pH electrodes, such as PG13.5, SMART sensors, Vario Pin, YEF and DIN connectors can be installed in the PR10.
  • Integrated protection cage
  • A "scraper" is built-in to each assembly to effectively scrape or wipe off the
    process from the PR10's shaft as it is being retracted from the process.
  • A safe "through the valve" insertion and retraction design
  • Simplified installation by optional ball valves with flanged or tapered connections
  • Optional flush port accessories makes it easy to keep sensors moist (pH) and clean, and also provides access for calibration if desired.
Overview:

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

Industries:
Application Note
Overview:

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.

Overview:

In the past, the boiler feed tank systems in sugar factories had to be checked several times a day to make sure there were no sugar solution leaks. This was a very laborious process and, as continuous monitoring was not possible, monitoring results were not reliable. When a leak occurred, recovery operations were very costly and time-consuming.

Industries:
Overview:

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.

Overview:

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.

Industries:
Overview:

Application Description

Many Ethanol plants running today are using a combination style pH electrode with a non-flowing reference to measure pH in the Mash Slurry transfer line from the Mash slurry mix tank to cook.  The Mash is being pumped out of the Mash Slurry tank is at approximately 82 °C and  2 to 4 bar (180 °F and 40 to 60 psig).

The original pH electrode systems that were installed during plant construction are online retractable assemblies and are mounted in orientations from completely horizontal to completely vertical and everywhere in between.

The Problem

The combination probe that is being used will typically drift out of calibration very quickly.  Also, the probe is damaged sometimes from excessive removal from the process.  The reason this probe drifts out of calibration is due to the fact that the non-flowing reference system plugs and becomes fouled by the mash passing by it.  pH measurements are only as good as the reference required to make this measurement.  If the reference is not doing its job, the measurement electrode will drift.

Process Overview

Product Recommendations

Yokogawa manufactures a multi-probe holder called the FF20 – flow through fitting or the FS20, which is pH chamber assembly with ½” NPT process connections.  With these holders we use a combination electrode, part number:  SC21C-AGC55 for measurement and reference and a separate temperature sensor part number: SM60-T1.  The Yokogawa electrode system works due to the fact that the SC21C-AGC55 combination probe uses a pressurized reference system.  By using plant air regulated to a KCl reservoir, the SC21C-AGC55 utilizes a positive flowing reference that does not foul. 

Plants using this system typically check the pH measurement against a grab sample and only make adjustments if the sample and the online measured values are more than 0.2 pH difference from one another.  Typically, the system will not need daily or weekly calibrations.  Most plants will pull the electrodes once a month for cleaning and calibration in a standard 4 and 7 buffer solutions.

Installation Considerations

The Yokogawa pH system is not retractable from the process.  It is usually best to put the Yokogawa pH electrodes in a by-pass or recirculation line that you can add isolation valves for isolating the probes from the process for maintenance and calibration.  The probe assembly should be mounted downstream of the Slurry Tank transfer pump.  Ideally it will be in a recirculation line going back into the tank or into the suction side of the slurry pump.

The picture below shows an installation that is actually flowing from left to right.  The arrows indicate the direction of the mash flow through the recirculation line and back into the suction side of the pump.  You will get an idea of the installation of the Yokogawa probes and the pressurized reference KCl reservoir from this picture.  The reservoir pressure is typically set 1 to 2 psig above the slurry line pressure.  The KCl reservoir will require refilling every 2-3 months for most applications

Note: For additional information on this application contact the local Yokogawa Process Liquid Analyzer Department

Overview:

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.

Industries:

Looking for more information on our people, technology and solutions?


Contact Us
Top