Five Things to Know About Process Instrument Protection

Wireless Process Instrument
Courtesy Yokogawa 

The performance of every process is critical to something or someone. Keeping a process operating within specification requires measurement, and it requires some element of control. The devices we use to measure process variables, while necessary and critical in their own right, are also a possible source of failure for the process itself. Lose the output of your process instrumentation and you can incur substantial consequences ranging from minor to near catastrophic.

Just as your PLC or other master control system emulates decision patterns regarding the process, the measurement instrumentation functions as the sensory input array to that decision making device. Careful consideration when designing the instrumentation layout, as well as reviewing these five common sense recommendations will help you avoid instrument and process downtime.

Process generated extremes can make your device fail.
Search and plan for potential vibration, shock, temperature, pressure, or other excursions from the normal operating range that might result from normal or unexpected operation of the process equipment. Develop knowledge about what the possible process conditions might be, given the capabilities of the installed process machinery. Consult with instrument vendors about protective devices that can be installed to provide additional layers of protection for valuable instruments. Often, the protective devices are simple and relatively inexpensive.

Don't forget about the weather.
Certainly, if you have any part of the process installed outdoors, you need to be familiar with the range of possible weather conditions. Weather data is available for almost anywhere in the world, certainly in the developed world. Find out what the most extreme conditions have been at the installation site....ever. Planning and designing for improbable conditions, even adding a little headroom, can keep your process up when others may be down.
Keep in mind, also, that outdoor conditions can impact indoor conditions in buildings without climate control systems that maintain a steady state. This can be especially important when considering moisture content of the indoor air and potential for condensate to accumulate on instrument housings and electrical components. Extreme conditions of condensing atmospheric moisture can produce dripping water.

Know the security exposure of your devices.
With the prevalence of networked devices, consideration of who might commit acts of malice against the process or its stakeholders, and how they might go about it, should be an element of all project designs. A real or virtual intruder's ability to impact process operation through its measuring devices should be well understood. With that understanding, barriers can be put in place to detect or prevent any occurrences.

Physical contact hazards
Strike a balance between convenience and safety for measurement instrumentation. Access for calibration, maintenance, or observation are needed, but avoiding placement of devices in areas of human traffic can deliver good returns by reducing the probability of damage to the instruments. Everybody is trained, everybody is careful, but uncontrolled carts, dropped tools and boxes, and a host of other unexpected mishaps do happen from time to time, with the power to inject disorder into your world. Consider guards and physical barriers as additional layers of insurance.

Know moisture.
Electronics must be protected from harmful effects of moisture. Where there is air, there is usually moisture. Certain conditions related to weather or process operation may result in moisture laden air that can enter device enclosures. Guarding against the formation of condensate on electronics, and providing for the automatic discharge of any accumulated liquid is essential to avoiding failure. Many instrument enclosures are provided with a means to discharge moisture. Make sure installation instructions are followed and alterations are not made that inadvertently disable these functions.

Developing a thoughtful installation plan, along with reasonable maintenance, will result in an industrial process that is hardened against a long list of potential malfunctions. Discuss your application concerns with your instrument sales engineer. Their exposure to many different installations and applications, combined with your knowledge of the process and local conditions, will produce a positive outcome.

Application Advantages of Wireless Sensors for Process Measurement and Control

Industrial Wireless Access Point
Courtesy Yokogawa

Wireless sensor technology is not new, but is still in an adoptive stage in many industries. New technologies are commonly adopted first by companies and industries that can justify the premium cost of newly released technology. The adoption process is similar to that of business computers. Early models were incredibly expensive to purchase and required a very large budget to keep operational. As time passed, the machines became less expensive to purchase and own, allowing a greater segment of the business world to justify their purchase and use. Wireless process measurement and control is following a similar path, with more and more facilities considering the potential for application of these devices.

I had always considered wireless sensing devices as a great way to be rid of cabling, but limited my thinking to fixed installations. A personal confession....Sometimes it's really hard to get my mind out of the box when I tape it shut. Anyway, I came across this application case from Yokogawa, a leading worldwide manufacturer of process measurement and control equipment and an enormous array of other industrial equipment. The case study illustrates how a tire manufacturing operation used wireless sensing technology to enhance the performance of their pressure test setup. The case study, shown below, shows the actual product part numbers used and provides a schematic and description of how the system was beneficially used. After my own reading of the case, I am now thinking of more potential applications that could benefit from a wireless configuration.

Read the case, it's short and concise. A sales engineer can provide you detailed information on the specific products used in the application. If you come up with some potential wireless process measurement applications of your own, contact an application specialist and explore the possibilities.

Wireless Process Measurement - Case Study of Plant Floor Testing Rack from Miller Energy, Inc.

Know Your Control Valve Basics?

Industrial Control Valve Cutaway View
Courtesy Cashco

Understanding basic operation and function of control valves, an integral part of many industrial process control loops, is essential for the process engineer, operator, or other stakeholder. This presentation outlines control valve operation, major components, and terminology used to describe valve parts, functions, and principles of operation. A useful reference for stakeholders in need of a refresher course in order to understand what the engineers are saying, it also provides detailed illustrations, charts, and description that will prove valuable to the more technical minded.


What you will find:

• Terminology: A glossary of terms commonly used in the control valve world.
• Control Valve Basic Designs: Control valve classifications, cutaway illustrations showing the operating structure of different valve types, comparisons of varying valve designs.
• Characterization and Trim Design: Flow characteristic curves and comparisons for different valve types, showing how flow responds to valve position change.
• Control Valve Technical Considerations: FTC vs FTO, illustrations showing valve operation.
• Force-Balance Principle: Illustration and formula explanations of this basic operating principle.
• Actuator Basic Designs: Illustrations showing the differing arrangements for actuator operation.
• Control Valve Unit Action: Illustrations, diagrams, and explanations of a range of valve operating conditions, including loss of electrical power and loss of instrument air supply.
• Actuator Benchset Range: Shows practical relationship between instrument air pressure and valve ability to properly operate at various pressure conditions.
• Valve Positioner Basics: Definition of valve positioning, reasons to use a positioner, schematic illustrations of control loops.
• Control Loop Action: Charts and provides examples of 16 combinations of Process, Controller, Positioner, and Control Valve combinations.
• Control Valve Packing Designs: Describes and defines packing, common problems, current state of the art. Cutaway illustrations of various packing arrangements.
• Seat Leakage: Classifications, comparisons of different materials.

There is something of value in the document for everyone, and you will undoubtedly pick up something useful. Thanks go out to the engineers at Cashco for putting this together. You can discuss any aspect of your control valve applications with a product specialist. Your contact is always welcome.

Basic Operation & Function of Industrial Control Valves from Miller Energy, Inc.

Eliminate Glass Tube Level Gauge Maintenance Costs

Magnetic Level Indicators
Courtesy Orion Instruments

Industrial process control often requires the accurate measurement of liquid level within a tank or other vessel. There are numerous device technologies and vendors from which to choose. A recent post on this blog detailed one of the available methodologies, the magnetic level indicator. I urge you to review that short post to familiarize yourself with the operating principles and advantages of applying a magnetic level indicator, not only on future projects, but as a possible replacement of some of your existing level indication instruments.

Orion Instruments, a Magnetrol company, has authored a case study showing how the replacement of glass tube level gauges with magnetic level indicators can reap substantial cost savings over the product lifetime. The case study, included below, takes but one minute of your time to read, and delivers a compelling incentive to consider magnetic level indicators (MLI) for your new projects, even as cost saving replacements for existing glass tube level gauges.

Read the case study. Contact a product specialist to discuss your application for new or replacement level indicators.

Orion instruments magnetic level indicators case study from Miller Energy, Inc.

Magnetic Level Indicators - Knowledge Base and Selection Guide

Magnetic Level Indicators
Courtesy Orion Instruments

Industrial process control frequently involves the storage of liquid in vessels or tanks. Continuous and accurate indication of liquid level within the tank is an essential data point for safety and process management. While there are a number of methods and instrument types utilized to provide tank level measurement, the instrument of choice is often a magnetic level indicator, also referred to as a magnetic level gauge. Its use for providing level indication has a number of positive attributes:

• Construction that is resistant to breakage.

• Measuring indicators, switches, and transmitters mounted externally, without contacting the medium being measured.

• Maintenance free operation. No regular cleaning needed.

• Readable level indication from greater distance than glass sight gauges.

• Magnetic level indicators can accommodate greater fluid level ranges without the need for multiple instruments.

Orion Instruments, a Magnetrol company and industry leader, has produced a comprehensive guide to magnetic level gauges, switches, transmitters, and related products. It delivers experts and newcomers an understandable and clear description of the technology and principals of operation behind magnetic level gauges and instruments. The guide also assists the reader in properly specifying and selecting the best instrument configuration for an application. A table of contents at the front of the document helps readers to quickly find the information they need.

Take a couple minutes to roll through the document and you are likely to find new and useful application tips and product information. Any questions about magnetic level indicators or your process measurement and control applications can be clearly addressed by a product specialist.

Orion instruments magnetic level gauge & instrument selection guide from Miller Energy, Inc.

Process Gas Chromatograph with Practical Implementation of Parallel Chromatography

GC8000
Process Gas Chromatograph
Courtesy Yokogawa Corp.

Gas chromatography is a common analysis tool employed in many areas of industry, including oil and gas, pharmaceutical, chemical, and others. Yokogawa Corporation of America has developed and been delivering top tier GC performance with their GC8000 Process Gas Chromatograph for use in oil and gas, and other industrial applications.

In addition to the ruggedness and reliability for which Yokogawa gas chromatographs are well known, the GC8000 brings a number of innovations and improvements to the company’s process gas chromatography product offering.

> Color touchscreen HMI for easy operation

> Advanced predictive diagnostics and software functions monitor key performance indicators during each analysis to verify analyzer is operating within proper tolerances.

> Parallel chromatography is made practical through the use of the GC Modules provided as part of the GC8000. Virtual GCs can be set up inside a single GC with GC Modules to measure multiple streams simultaneously.

The graphics below expand on this overview of the GC8000 Process Gas Chromatograph, the culmination of Yokogawa’s 55 years of experience in the field. For more detailed information, or to discuss your application specifics, contact a product specialist.

Process Gas Chromatograph - Yokogawa GC8000 from Miller Energy, Inc.

Magnetic Flow Meter – When Is It the Right Selection for Your Project?

Industrial Magnetic Flow Meter

Courtesy Yokogawa Corp.

Flow measurement is a ubiquitous function in the industrial process control field. Anywhere there are pipes, somebody wants to know what, and how much, is passing through them. Fortunately for us engineers, there is a wide array of industrial flow meters capable of measuring some physical characteristic of fluid moving within a pipe that can be translated into a useful measurement of flow rate.

In industry, there are a number of different technologies used to measure a physical property related to fluid motion, referred to as magnetic, ultrasonic, vortex, Coriolis, differential pressure, and several others. Each methodology exists in the market because it may perform better or cost less when meeting certain performance requirements. This article is focused on magnetic flow meters and when they may be a good candidate for your project.

Here is a list of some of the positive attributes of magnetic flow meters.

• Magnetic flow meters have no moving parts, always a plus.
• General construction arrangement allows for use of an interior liner for corrosion resistance.
• With no sensor insertions into the fluid flow, the impact of the instrument on the flow is minimized.
• Accuracy, when compared to other technologies, is high.
• Application to laminar, turbulent, and transitional flow profiles is permissible.
• General insensitivity to fluid viscosity, specific gravity, temperature and pressure.
• Magnetic flow meter technology can be applied to a very wide range of pipe sizes.
• Device responds rapidly to changes in fluid flow.
• Can be successfully applied to liquids containing heavy particulates.
• Generally long service life with little maintenance.

There are, though, some points about magnetic flow meters which may make them unsuitable for your application.

• Magnetic flow meters only work on liquids with conductivity above a certain threshold. They may be unsuitable for use with hydrocarbons and high purity water for this reason.
• Cannot be used to measure gas flow.
• Pipe must be grounded.
• Typically, the pipe cross section must be filled by the fluid being measured.

This listing of positives and negatives is intended to be very general in nature. Some manufacturers may have product application solutions that overcome some of the negatives, while others may not be able to deliver all of the positives.

Your best course of action:

Use this general overview to start shaping you understanding of where magnetic flow meters may be a good option, and contact a product application specialist to discuss what you want to accomplish. Combining your process knowledge with their product knowledge should move you toward a good solution.