Friday, April 29, 2016

Process Instrument Selection a Breeze with this Online Tool

yokogawa product selector
Find process instruments fast!
Yokogawa Corporation of America, an industry recognized source for innovative process measurement and control products, has made available an easy to use product selection tool for those navigating through the company's extensive product offering. The Product Finder is a great time saver that enables a user to quickly locate product and technical information on Yokogawa products that meet the user's selected criteria.

Let's step through a quick example. You will see how this quick and easy to use tool saves time by navigating quickly to the website pages detailing products meeting your requirements.

The Product Finder is accessible through a number of links throughout Yokogawa's network of Reps. Clicking the link lands you on the start page of the Product Finder. For this example, I am going to search for a flow meter with the following characteristics:
  • Mass flow measurement 
  • Non-conductive liquid
  • Accuracy of 1%
  • Flow measurement device must have an integral transmitter
  • Tri-clamp connections

Above, I declared my location as United States. The next step, shown below, is to select "Flow" as the measurement parameter. You will see in the drop down menu that there are many measurement elements that can be selected, with Yokogawa products for each.

My selection of "Flow" returns a list of all the company's flow measurement devices, of which there are many (this cropped screenshot, shown below, only shows four, but there were many more) . This is where the selector really helps you. Instead of examining several or many different models, the user can focus the search by adding more product characteristics. You can see the list of prompting questions on the left side of the page. Answering these will narrow the search results to the show only the products meeting all the criteria specified by the user.

The next image (below) shows selections of all  my sample product attributes entered on the left column. Note that there is now only a single product that matches all of my sample criteria. The whole process took less than two minutes. By clicking on the "View More Details" button below the product image, I gain access to all of the available technical, support, and product data for my selected flow measurement device.

For more help and personal assistance in Kansas, Missouri, Iowa and Nebraska, contact Power Specialties. Combine their product knowledge and expertise with your process know-how for the best solutions.

Thursday, April 28, 2016

Fundamentals of pH Control in Industrial, Municipal, and Commercial Applications

pH Meter
Handheld pH Meter & Sensor
(courtesy of Yokogawa)
Analytical measurement and control of pH within a system is necessary for many processes. Common applications include food processing, wastewater treatment, pulp & paper production, HVAC, power generation, and chemical industries.

To maintain the desired pH level in a solution, a sensor is used to measure the pH value. If the pH is not at the desired set point, a reagent is applied to the solution. When a high alkaline level is detected in the solution, an acid is added to decrease the pH level. When a low alkaline level is detected in the solution, a base is added to increase the pH level. In both cases the corrective ingredients are called reagents.

Accurately applying the correct amount of reagent to an acid or base solution can be challenging due to the logarithmic characteristics a pH reaction in a solution. Implementing a closed-loop control system maintains the pH level within a certain range and minimizes the degree to which the solution becomes acidic or alkaline.

An example of an automatic pH level control system is a water treatment process where lime softened water is maintained at a pH of 9, using carbon dioxide as a reagent. As the untreated water (or influent) enters the tank, the pH is continuously monitored by the pH sensor. The sensor is the feedback device to the controller where the setpoint is compared to the control value. If the values are not equal, the controller sends a signal to the control valve that applies carbon dioxide to the tank. The reagent is applied to the tank at varying rates to precisely control the pH level. With the pH level at 11 detected by the sensor, the controller commands the control valve to open and introduce more carbon dioxide. As the increased carbon dioxide mixes with the influent, the pH is lowered in a controlled manner. Reaching the setpoint, the carbon dioxide flow is minimized and the process is continually monitored for variation. The effluent is the treated water that is discharged out of the tank. The process continues to provide the lime softened water at the desired pH level.

Saturday, April 16, 2016

A Better Load Cell for Weighing Heated, Vibration Prone Process Vessels

Heated Tank with KIS load cells
Most load cells are designed to handle vertical force and cannot discern errors introduced from side loading and/or torque loading. In real world conditions, though, load cells see much more than vertical loading, and unfortunately, can output erroneous values. While they are excellent for static weighing situations, such as scales, load cells typically can’t handle the rigors of process vessel applications.

A case in point is a chemical manufacturer with an several, existing three cubic meter batching tanks. It was decided the tanks needed modifications to provide more accurate weighing of the individual ingredients. The existing load cells were experiencing errors due to thermal expansion of the vessel, and the resultant side loads from expansion. Additionally there was a problem with vibration in the plant. A better solution was needed, and whatever the solution would be, the customer made it clear the new weighing system must provide system accuracy in the range of ±0.1%.

load cell issues
Load cell performance problems causes.

BLH KIS sensor
BLH KIS sensor
An approach to deal mechanically with the thermal cycling while using the same type of load cell was discussed. It involved several mechanical modifications that required significant and costly structural changes.

Another suggestion was to evaluate a unique load cell design that was particularly tolerant against thermal expansion, vibration, and high lateral forces - the BLH Nobel KIS series.  The KIS load cell offered some obvious advantages over rebuilding the tanks supports and frame, namely time and expense. Beyond the short installation time and easy modification, the KIS also offers excellent reliability and accuracy.

BLH Instrument
BLH Instrument
The customer decided to “take the easy way out” and just replace the old, error-prone load cells with KIS load cells. Installation and start-up was very easy, taking very little time. After installation, the customer was pleasantly surprised by the high accuracy of the new KIS load cells, despite the thermal expansion of the vessel and the inherent vibration.

The video below gives an excellent view inside the KIS design and why its ideal for process vessels.

Saturday, April 9, 2016

Basics of pH Measurement

pH Scale
pH of Common Items
(image courtesy of
pH is a numeric scale used to designate the acidity or alkalinity of an aqueous solution. Solutions with a pH below 7 are acidic and solutions with a pH higher than 7 are basic. Pure water is considered neutral and are neither an acid nor a base.

pH measurement is very important in many industries including medicine, chemistry, agriculture, food science, environmental science, chemical engineering, water & wastewater treatment, and many others.

pH electrodes and sensors are the sensing portions of a pH measurement. Various installation options including retractable, flow thru, immersion, and direct insertion. Proper pH electrode/sensor selection is critical for optimal measurement results.

2 wire analyzer
2 wire transmitter (Yokogawa)
pH meters, analyzers and transmitters are used for continuous process monitoring of pH to ensure water/product quality, monitor effluent discharge, batch neutralization, pulp stock, scrubbers, cooling towers, chemical, water/wastewater treatment and many other applications.

Four Wire Analyzers: 4-wire analyzers separate the power supply from the measurement output. As a minimum we need two wires for the power supply and two wires for the current output of the analyzer.

Two Wire Analyzers: 2-wire analyzers combine the wires for current output, power supply, and digital communication.

The document below (courtesy of Yokogawa) provides a comprehensive understanding of pH/ORP measurement and how to achieve reliable results. Basic information on the principles of measuring pH/ORP, the construction of the sensing elements and their basic use in process applications are provided.

For more information, contact:
Power Specialties, Inc.
9118 E. 72nd Terrace
Raytown, MO 64133
Toll Free: (800) 432-6550
Phone: (816) 353-6550
Fax: (816) 353-1740