A blog specializing in pressure, temperature, level and flow instrumentation, control valves, process analyzers, and all other areas of process measurement. Courtesy of Miller Energy, a New Jersey, New York, Pennsylvania, and Ohio process instrumentation Rep and Distributor.
Showing posts with label process control. Show all posts
Showing posts with label process control. Show all posts
Unfortunate events can provide useful lessons for industrial
process operators
Industrial accidents range in severity and impact from minuscule to catastrophic. As operators, owners, or technicians involved with industrial operations, we all have a degree of moral, ethical, and legal responsibility to conduct our work in a manner that does not unduly endanger personnel, property, or the environment. Maintaining a diligent safety stance can be helped by reviewing industrial accidents at other facilities. There is much to learn from these unfortunate events, even when they happen in an industry that may seem somewhat removed from your own.
The U.S. Chemical Safety Board, or CSB, is an independent federal agency that investigates industrial chemical accidents. Below, find one of their video reenactments of an explosion that occurred in Texas in 2013, along with their findings regarding the cause of the incident. Check out the video and sharpen your senses to evaluate potential trouble spots in your own operation.
Contact Miller Energy for any safety related information you may need concerning their lines of industrial process control products.
New Model R96 Non-Contact Radar Level Transmitter Courtesy Magnetrol International
Magnetrol is a well known manufacturer of level and flow measurement instrumentation for the industrial process control field. The company recently released the Model R96 Non-Contact Radar Level Transmitter for applications where continuous fluid level measurement is required.
The company's description of the product...
"Virtually unaffected by the presence of vapors or air movement within a vessel’s free space, the two-wire, loop-powered, 6 GHz Radar transmitter measures a wide variety of liquid media in process conditions ranging from calm product surfaces and water-based media to turbulent surfaces and aggressive hydrocarbon media."
The new product offers features that combine to make a state-of-art instrument for accurate continuous level measurement. A product brochure is included below. Contact application specialists to formulate the right product configuration for your level measurement challenge.
Many valves can be specially prepared for high purity or oxygen service
Oxygen is used extensively throughout a wide range of industrial processes. Medical, deep-sea, metal cutting, welding, and metal hardening are a few examples. The steel industry uses oxygen to increase capacity and efficiency in furnaces. As a synthesis gas, oxygen is also used in the production of gasoline, methanol and ammonia.
Odorless and colorless, oxygen is concentrated in atmospheric air at approximately 21%. While O2, by itself, is non-flammable, it vigorously supports combustion of other materials. Allowing oils or greases to contact high concentrations of oxygen can result in ignition and possibly explosion. Oxygen service preparation of an industrial valve calls for special cleaning processes or steps that remove all traces of oils and other contaminants from the valve to prepare for safe use with oxygen (O2). Aside from the reactive concerns surrounding oxygen, O2 preparation is also used for applications where high purity must be maintained and valves must be free of contaminants.
Gaseous oxygen is noncorrosive and may be used with a variety of metals. Stainless steel, bronze and brass are common. Liquid oxygen presents unique challenges due to cryogenic temperatures. In this case, valve bodies, stems, seals and packing must be carefully chosen.
Various types of valves are available for oxygen service, along with a wide array of connections, including screwed, socket weld, ANSI Class 150 and ANSI Class 300, DIN PN16 and DIN PN40 flanged ends. Body materials include 316 stainless steel, monel, bronze and brass. Ball and stem material is often 316 stainless steel or brass. PTFE or glass filled PTFE are inert in oxygen, serving as a common seat and seal material employed for O2 service.
Common procedures for O2 service are to carefully deburr metal parts, then meticulously clean to remove all traces of oil, grease and hydrocarbons before assembly. Valve assembly is performed in a clean area using special gloves to assure no grease or dust contaminates the valve. Lubricants compatible with oxygen must be used. Seating and leakage pressure tests are conducted in the clean area, using grease free nitrogen. Specially cleaned tools are used throughout the process. Once assembled, the valves are tested and left in the open position. A silicone desiccant pack is usually inserted in the open valve port, then the valve ports are capped. A warning label about the desiccant pack's location is included, with a second tag indicating the valve has been specially prepared for oxygen service. Finally, valves are individually sealed in polyethylene bags for shipment and storage. Different manufacturers may follow slightly differing protocols, but the basics are the same. The valve must be delivered scrupulously contaminant free.
The O2 preparation of valves is one of many special production variants available to accommodate your special application requirements. Share your valve requirements and challenges with a valve specialist to get the best solution recommendations.
Cavitation produces bubbles in flowing process liquids
Consider a generic industrial fluid process control operation. There are pumps, valves, and other components installed in the process lines that, due to their interior shape or their function, cause changes in the fluid motion. Let's look specifically at control valves and how their throttling operation can create conditions able to greatly impact the valve itself, as well as the overall process.
Fluid traversing a control valve can undergo an increase in velocity when passing the constriction presented by the valve trim. Exiting the trim, fluid then enters the widening area of the valve body immediately downstream with a decrease in velocity. This change in velocity corresponds to a change in the kinetic energy of the fluid molecules. In order that energy be conserved in a moving fluid stream, any increase in kinetic energy due to increased velocity will be accompanied by a complementary decrease in potential energy, usually in the form of fluid pressure. This means the fluid pressure will fall at the point of maximum constriction in the valve (the vena contracta, at the point where the trim throttles the flow) and rise again (or recover) downstream of the trim.
This is where cavitation begins.
If the fluid being throttled is a liquid, and the pressure at the vena contracta is less than the vapor pressure of the liquid at the flowing temperature, portions of the liquid will spontaneously vaporize. This is the phenomenon of flashing. If, subsequently, the pressure of the fluid recovers to a level greater than the vapor pressure of the liquid, any flashed vapor will rapidly condense, returning to liquid. This collapse of entrained vapor is called cavitation.
Flashing, the generation of vapor bubbles within the liquid, will precede and set the stage for cavitation. When the flashed vapor bubbles condense to liquid they often do so asymmetrically, with one side of the bubble collapsing before the rest of the bubble. This has the effect of translating the kinetic energy of the bubble’s collapse into a high-speed “jet” of liquid in the direction of the asymmetrical collapse. These liquid “microjets” have been experimentally measured at speeds up to 100 meters per second (over 320 feet per second). What is more, the pressure applied to the surface of control valve components in the path of these microjets can be intense. An individual microjet can impact the valve interior surfaces in a very focused manner, delivering a theoretical pressure pulse of up to 1500 newtons per square millimeter (1.5 giga-pascals, or about 220000 PSI) in water. In an operating fluid system, this process can be continuous, and is known to be a significant cause of erosive wear on metallic surfaces in process piping, valves, pumps and instruments. As the rapid change in pressure takes place, the bubbles (voids in the liquid) collapse (implode), and the surrounding metal surfaces are repeatedly stressed by these implosions and their subsequent shock waves.
Consequences for control valves, as well as for the entire control process, vary and are often destructive. They may include:
Loud noise
Strong vibrations in the affected sections of the fluid system
Choked flow caused by vapor formation
Change of fluid properties
Erosion of valve components
Premature destruction or failure of the control valve
Plant shutdown
The video provides a visual demonstration, through clear piping, of what happens inside the piping system when a valve is operated in a manner that causes substantial cavitation.
The solution lies in minimizing the potential for cavitation to occur through proper valve selection and sizing, along with coordinating operating characteristics of pressure drop inducing components with the total system performance. One valve manufacturer's recommendations are summed up in four basic approaches.
Avoidance of cavitation through proper valve selection. Use a valve with a rated liquid pressure recovery factor greater than that required for the application. Some applications may be suitable for the use of an orifice plate downstream of the valve.
Cavitation Tolerant Components capable of withstanding limited amounts of cavitation without excessive wear. Increased flow noise is likely to accompany this route.
Prevention of cavitation through the use of valve trim design that reduces pressure in several steps, avoiding excessive flashing. These valves can be expensive, but their effectiveness makes them an alternative worth considering.
Containment of the harmful effects of limited to moderate cavitation through trim designs that eliminate contact of the fluid with metal surfaces which are more susceptible to damage.
Share your requirements and application challenges with a valve specialist and gain insight through their recommendations. Combining your process knowledge with their product application expertise will yield a great solution.
Direct insertion and external mount versions of Orion JM4 Magnetostrictive Level Transmitter Courtesy Orion Instruments
Orion Instruments, a world class manufacturer of magnetic level indicators, level switches, and level transmitters, has released a new product for use in the industrial process measurement and control field. Their Jupiter Model JM4 magnetostrictive transmitter incorporates the company's many years of research, development, and field experience to provide a safer, simpler, and smarter transmitter for liquid level measurement and control.
The new model from Orion boasts level measurements with accuracy as high is +/-0.05" (1.27mm). The transmitter head can be rotated up to 310 degrees with an option for remote mounting. Variants are available for direct insertion or external mounting, with approvals for a number of area classifications. There are other valuable features to this series of level measurement instruments that reflect Orion's expertise in the field.
Browse the new product brochure included below. It provides illustrations of the product and its operating principle, along with dimensioned drawings and a listing of all the product options and variants. You can always obtain whatever information you need about Orion level measurement instruments from a product specialist. Share your liquid level measurement challenges and requirements with them for recommendations on the best solutions.
Coriolis mass flow meters are widely used throughout the process measurement and control field. Their basic operating principle, combined with modern sensor and signal processing technology, provide a list of positive aspects.
Directly measure mass flow rate based on the
principle of measurement. Measure the mass flow rate with high accuracy of ±0.1%. Provide a wide usable measurement range. Deliver density measurement based on oscillating
frequency. Not materially impacted by fluid viscosity or density. Coriolis flowmeters also do not need straight pipe sections upstream or downstream
of the flowmeter. They also have the ability to measure non-conductive fluids.
I have included an interesting video, produced by Yokogawa, a world class manufacturer of industrial process measurement and control instrumentation. It provides a clear and insightful illustration of the Coriolis principle and how it is used to provide accurate mass flow measurement.
Share your process measurement and control challenges with an instrumentation specialist. Combining your detailed process knowledge and their product application expertise will yield positive solutions.
At Miller Energy, use website chat to connect directly with technicians and product specialists.
Miller Energy will be rolling out real time chat on their website in early February. This new feature is another in a long line of continuous improvements the company has brought on line to better serve and connect with their customer base. On the desktop version, a chat widget will appear on every website page as a small tab on side of the display. A click of the widget will open a chat window and the visitor can type in their question or comment. Site visitors using mobile devices are afforded the same functionality.
Steve Collins, the Miller Energy website designer at CMS4i, commented on MEI's increased level of connectivity..
"The chat implementation at Miller Energy is notable because
it connects customers directly with technically qualified employees that are
part of the day to day company operations. Customers will be communicating with
real “hands on” engineers and specialists familiar with process measurement and
control, and engaged in the field on a daily basis."
Look for the chat function on the Miller Energy website in early February. Use it to get fast answers to your questions from knowledgeable and engaged industry professionals.
Integrated Controller and Data Acquisition Device Courtesy Yokogawa
Are you a designer or builder of process control systems? Selecting hardware and componentry to provide the functionality, accuracy, and accessibility required to meet process or equipment performance demands can pose some very distinct challenges. When faced with a scope of work that includes multiple PID control loops, data recording, and networking, do you tend to favor using a collection of separate devices for each function, or a consolidated unit that integrates all of the needed functions?
I have designed many control systems throughout my career, and tended toward using separate devices initially. As I gained experience and the feedback that comes from having units in the field for a number of years, my thinking changed and my preference for integrated "single box" solutions began to predominate.
Some reasons to use a consolidated device:
Likely to take up less panel space than a combination of individual devices.
Substantially reduced wiring, cabling.
No tasks associated with getting individual devices to work together, if that is needed. The integrated unit comes out of the box with all of that already accomplished.
Reduced parts count.
Simplified panel wiring plan.
A single HMI encompassing all the provided functions.
Anyone, end users, service techs, trainers, quality control, that needs to learn about the operation of the system has a single instruction manual to review or learn. Since the functions all come in one unit, there is often some streamlining to the learning process.
OEMs may be able to use a single component to provide the necessary functions for numerous product versions, bringing measurable time savings throughout the product design, fabrication, and support functions of their organization.
If spares are required, there is only one.
I have enjoyed good results employing devices that combine numerous functions into a single package. There is a data sheet below, so you can see more about an industrial control, recording, networking device that packs a useful range of functions into a compact unit.
On your next process control project, consider whether going consolidated or discrete is better for your needs. Talk to a process controls expert and get some additional input. Good solutions are out there.
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.
Attaining the best available performance and accuracy from any measuring device utilized in an industrial process is always advantageous. The scale of most industrial processes is such that even small inaccuracies in process measurement produce financially tangible impact. Differential pressure measurement, with wide application in the industrial process sphere, can be improved with the addition of a means to compensate for the real world effects of static pressure upon instrument performance. Yokogawa Corporation has developed a means to dynamically compensate for static pressure effects in field measurements. The brief technical presentation below will help you understand how static pressure effects can impact your field measurements, as well as how Yokogawa’s Real-time Dynamic Compensation works to offset its impact. More detailed product and application information is available from your Yokogawa specialist.
Industrial process control valves are available in a staggering array of materials, types, and configurations. An initial step of the selection procedure for a valve application should be choosing the valve type, thus narrowing the selection field to a more manageable level. Valve "types" are generally defined by the closing mechanism of the valve.
Butterfly Valve Courtesy Crane CPE
A butterfly valve has a disc that is positioned in the fluid flow path. It rotates around a central axis, the stem, through a 90 degree arc from a position parallel to the flow direction (open) to perpendicular (closed). A variety of materials are used in the valve body construction, and it is common to line the valve with another material to provide special properties related to the process media.
What might make a butterfly valve a beneficial selection over another valve type?
The closure arrangement allows for a comparatively small size and weight. This can reduce the cost, space, and support requirements for the valve assembly.
Generally low torque requirements for valve operation allow for manual operation, or automation with an array of electric, pneumatic, or hydraulic actuators.
Low pressure drop associated with the closure mechanism. The disc in the flow path is generally thin. In the fully open position, the disc presents its narrow edge to the direction of flow.
Quarter turn operation allows for fast valve operation from fully closed to fully open.
Some throttling capability is provided at partially open positions.
Small parts count, low maintenance requirements.
What may be some reasons to consider other valve types?
Butterfly Valve Courtesy Crane CPE
Butterfly valve throttling capability is generally limited to low pressure drop applications
Cavitation can be a concern.
Some sources mention the possibility of choked flow as a concern under certain conditions.
Butterfly valves, like other valve types, have applications where they outperform. Careful consideration and consultation with a valve expert is a first step toward making a good selection.
Many industrial process control operations require fluid flow measurement as an essential element in the process design. Accurate flow measurement can be obtained with the proper application and installation of a flow meter as part of the fluid transfer system.
Industrial flow meters employ differing technologies to directly or indirectly measure fluid flow rates. Among the many available technologies for fluid flow measurement, vortex flow meters, magnetic flow meters, Coriolis flow meters, and rotameter flow meters are among some of the most common found in industry.
Coriolis Flow Meter Courtesy Yokogawa Corp.
Rotameter Flow Meters Courtesy Yokogawa Corp.
Each of the separate technologies have attributes which can make them more suitable to certain applications. Selecting the most appropriate flow measurement technology for an application is one of the initial and crucial steps to designing a well functioning fluid measurement system.
Selection criteria, such as fluid temperature, pressure, and velocity will be part of the selection process. Additional considerations include whether the fluid may be abrasive, corrosive, clean or dirty. The state of the fluid, liquid or gas, must also be considered.
The table below provides quick general guidance on which technologies to consider, based upon the factors outlined above. This will help you better focus further product selection research efforts.
Selecting the right valve is not always an easy task, especially since it may be something that you do infrequently. Manufacturers often have knowledgeable local representatives that are experienced in this field and more than willing to contribute their expertise to your selection process.
Welcome! We hope (over time) you find this blog interesting to visit and it becomes a trusted resource for process measurement and control. We plan on weekly educational and informative blog posts innovative process control solutions, insight to how industrial controls work, and new products that solve tough engineering challenges. Please come back often!
