Flumes For Water System Open Channel Flow Measurement

fiberglass cutthroat flume open channel flow measurement
This cutthroat flume is one of several types of flumes
used to facilitate open channel flow measurement.
Image courtesy Tracom Fiberglass Products
The measurement of flowing water in an open channel can be facilitated by applying known methodologies and a specifically shaped restriction in the flow path. The restriction is called a flume.

A flume, as applied to open channel flow, is a fixed structure in the flow path that directs or restricts the flowing water in a manner that allows a measurement of the fluid depth at a defined point to be translated into a volumetric flow rate. There are several different types of flumes, each with a characteristic measuring procedure used to determine flow volume. Applications for flumes and their open channel flow measurement techniques are commonly found in agriculture, sewer systems, water treatment, and industrial effluent measurement stations.

Flumes can provide measurement accuracy suitable for many uses. Advantages are their simplicity, ease of maintenance, comparatively small footprint, and ability to measure large flows. Fiberglass flumes provide solid long term performance due to their corrosion resistance and smooth, easy to maintain, surface. Prefabricated units can be shipped to an installation site and easy installed.

Share your open channel flow measurement challenges with application specialists, leveraging your own knowledge and experience with their product application expertise.

Groundwater Monitoring Instrumentation

groundwater level temperature pressure measurement instrument
The Level TROLL groundwater monitoring instrument can be
suspended in a well and log temperature, pressure, and level.
Image courtesy In-Situ
In-Situ specializes in the manufacture of instruments used for monitoring groundwater and other water testing functions. In the fields of aquaculture, remediation, energy, mining and research, In-Situ is regarded as an innovator, providing reliable top quality water monitoring equipment.

The company's Level TROLL line of water level data loggers are specifically intended for aquifer characterization. The instruments provide continuous level, pressure and temperature readings when suspended in a well. The battery operated units can function for very long periods, holding up to 260,000 data points.

The Level TROLL Instrument is completely sealed and contains no user-serviceable parts. The instrument includes pressure and temperature sensors, a real-time clock, microprocessor, sealed lithium battery, data logger, and memory. Instruments are available in a variety of pressure (depth) ranges with vented and non-vented sensors. Placement within a well can be accomplished with In-Situ's Rugged Cable System, custom built for each application to provide direct reading operation. The cable assembly includes titanium twist-lock connectors, desiccant to prevent condensation in the vent tube, shielded connecting cable, and a placement grip for secure deployment. A second option for instrument deployment is suspension via a polyurethane coated stainless steel cable for applications that do not require direct reading, only data logging.

There are several models from which to choose, and other products suitable for groundwater monitoring throughout many industries. Share your water monitoring requirements of all types with instrumentation specialists. Combine your own knowledge and experience with their product application expertise to develop effective solutions.

Open Path Laser Spectroscopy Gas Detection

MSA has been a leader in hazardous gas detection instruments and equipment for many years. Their addition of the Senscient ELDS™ open path gas detector to their already extensive array of gas detection instruments reinforces the MSA leadership position in the field.

The Senscient ELDS™ system consists of an infrared laser transmitter unit and a receiver. The distance between the two components can be up to 200 meters. The function of the system is to provide detection of a targeted hazardous or flammable gas.

The basic operating principle centers around the selective absorption of specific wavelengths of light by the target gas. The transmitter infrared output is selected to match signature absorption patterns of the gas to be detected, with the receiver unit and its signal processing electronics tuned for the same signature. The output signal from the detector indicates the amount in target gas present in the beam path, which is proportional to the degree of absorption at the signature wavelength .

The Senscient ELDS™ incorporates advancements and technology that make its operation more resistant to the adverse effects of the operating environment and other less than ideal installation conditions than previous generations of open path gas detectors.

The included video provides more insight into the operation of the Senscient ELDS™ system. Share your hazardous and flammable gas detection challenges with process instrumentation specialists, leveraging your own knowledge and experience with their product application expertise to develop an effective solution.

Vortex Flowmeters

vortex or multivariable flowmeter flow meter for process measurement
Multivariable vortex flowmeter combines flow, temperature
and pressure measurement into a single compact instrument
Image courtesy Krohne
Vortex shedding flowmeters provide process operators with consistent fluid flow rate measurements across a wide range of applications. These flowmeters measure the volumetric flow rate of steam, gas, and low viscosity liquids, boasting both versatility and dependability when used in conjunction with process systems.

Vortex shedding refers to the phenomenon wherein flowing gas or liquid form vortices around a solid object placed in the flow path. The measurement technology returns an indication of the process fluid velocity, which can then be used to provide volumetric or mass flow data. Vortex technology is well suited for many applications involving cryogenic liquids, hydrocarbons, air, and industrial gases. Vortex flow measurement requires contact between portions of the measurement instrument and the process media, so these flowmeters are commonly fashioned from a range of corrosion resistant materials.

The process of measuring the flow involves both the flowmeter and the ability for other instrumentation to measure the vortices themselves in order to calculate velocity. Ultrasonic sensors have become popular tools for measuring vortices. Applications involving flow measurement of high viscosity fluids are not suited for vortex technology because extremely viscous fluids do not behave in the same manner as lower viscosity fluids when their flow path is obstructed. Splitting higher viscosity fluids into concordant vertices is extremely difficult due to the internal friction present in highly viscous liquids.

Additionally, in order to split these process liquids, the piping through which the process material flows must be straight, and any disturbance or vibration in the pipe may impact the measurement. A vortex flowmeter will be in a fixed installation. This stationary element, operating without electrodes, can be advantageous for flow measurement in chemical applications utilizing low viscosity fluids.

The vortex shedding flowmeter is widely used for the measurement of steam flow. The high pressure and elevated temperature of steam, along with the variation that exists in most steam systems, have little negative impact on the operation of a vortex flowmeter. Vortex shedding flowmeters are often volumetrically based in terms of measurement, but their output can be combined with other fluid information to calculate mass flow. A product variant commonly available will combine the vortex flow measurement with temperature and pressure compensation, delivering three process measurements from a single installed device.

Share your process and flow measurement challenges with instrumentation specialists, leveraging your own knowledge and experience with their product application expertise.

Pressure Switch Design Details

Industrial process control applications present dynamic and varied requirements for measuring, monitoring and control. Each point calls for specific evaluation of the information needed from the process point for use in monitoring process performance, or control to be applied at the process point to regulate an outcome. Sometimes, a continuous analog signal is needed to provide indication across a range of values. Other times, it is only necessary to have notification of, or take action when, a certain temperature or pressure related event occurs. In those cases, a simple and reliable device can adequately meet the project requirements.

Pressure and differential pressure switches connect to a process and change their switch position when a setpoint condition is reached. The are simple to understand, easy to install, low in cost, and require little maintenance of attention. The switches are available in an extensive array of configurations, with options to fill out almost any application requirement.

SOR, Inc., globally recognized manufacturer of temperature and pressure switches, has produced this video outlining some of the distinctive features of their pressure switches for industrial process control applications. Share your process measurement and control requirements and challenges with product application specialists, and leverage your own process knowledge and experience with their product expertise to develop effective solutions.

Best Practices for Routing Control Signal to Multiple Devices

process signal conditioner modules isolator
Isolating transmitters are part of best practice for
retransmitting process signals
Image courtesy of Acromag
Acromag is a globally recognized leader in the design and manufacture of signal conditioning equipment for process measurement and control. On a daily basis they get calls on understanding 4-20 mA current loops and how to wire them with or without power supplies. The application note provided below can serve as a template for wiring Acromag modules, or those of similar design from other manufacturers, in applications. Download and save it for use as a reference when connecting field devices to a PLC, DCS, HMI, etc.

Share your process measurement and control challenges with application specialists, leveraging your own knowledge and experience with their product application expertise to develop effective solutions.

Eight Selection Criteria for Control Valves

globe valve with actuator and positioner
Control valve shown with actuator and positioner
Image courtesy Flowserve - Valtek
Proper selection with respect to a number of factors plays an important role in obtaining the desired performance from a control valve. Failure to make a properly considered selection can impact operation, productivity and safety. Here is a quick checklist of basics that need to be considered:
  • Control valves are not intended to be a an isolation valve and should not be used for isolating a process. 
  • Always carefully select the correct materials of construction. Take into consideration the parts of the valve that comes in to contact with the process media such as the valve body, the seat and any other wetted parts. Consider the valve's exposure to operating pressures and temperatures. Finally, also consider the ambient atmosphere and any corrosives that can occur and effect the exterior of the valve. 
  • Put your flow sensor upstream of the control valve. Locating the flow sensor downstream of the control valve exposes it to an unstable flow stream which is caused by turbulent flow in the valve cavity.
  • Factor in the degree of control you need and make sure your valve is mechanically capable. Too much dead-band leads to hunting and poor control. Dead-band is roughly defined as the amount of control signal required to affect a change in valve position. It is caused by worn, or loosely fitted mechanical linkages, or as a function of the controller setting. It can also be effected by the tolerances from mechanical sensors, friction inherent in the the valve stems and seats, or from an undersized actuator. 
  • Consider stiction. The tendency for valves that have had very limited travel, or that haven't moved at all, to "stick" is referred to as stiction. It typically is caused by the valves packing glands, seats or the pressure exerted against the disk. To overcome stiction, additional force needs to be applied by the actuator, which can lead to overshoot and poor control.
  • Tune your loop controller properly. A poorly tuned controller causes overshoot, undershoot and hunting. Make sure your proportional, integral, and derivative values are set). This is quite easy today using controllers with advanced, precise auto-tuning features that replaced the old fashioned trial and error loop tuning method.
  • Don't over-size your control valve. Control valves are frequently sized larger than needed for the flow loop they control. If the control valve is too large, only a small percentage of travel is used (because a small change in valve position has a large effect on flow), which in turn makes the valve hunt. This causes excessive wear. Try to always size a control valve at about 70%-90% of travel.
  • Think about the type of control valve you are using and its inherent flow characteristic. Different types of valve, and their disks, have very different flow characteristics (or profiles). The flow characteristic can be generally thought of as the change in rate of flow in relationship to a change in valve position. Globe control valves have linear characteristics which are preferred, while butterfly and gate valves have very non-linear flow characteristics, which can cause control problems. In order to create a linear flow characteristic through a non-linear control valve, manufacturers add specially designed disks or flow orifices which create a desired flow profile.
These are just a few of the more significant criteria to consider when electing a control valve. You should always discuss your application with an experienced application expert before making your final selection.

Two-Wire vs. Four-Wire Transmitter For Analog Process Signals - What to Consider?

industrial I/O modules for process signal conditioning
I/O modules are an integral part of process signal connectivity.
Image courtesy of Acromag
Transmitters are everywhere in process control. They take a sensor output signal,amplify and condition it, then send it to monitoring and decision making devices. The most common analog electrical signal used for transmitting process control signals is a 4-20 mA (milliampere) current flow. It has succeeded in its adoption for a number of reasons, not the least of which are its resistance to interference and ability to transmit a signal across a substantial length of cable.

Aside from the sensor connection, there are two basic wiring schemes for these devices. The simplest employs just two conductors to transmit the signal and coincidentally provide operating power for the transmitter electronics. This type of transmitter is commonly referred to as a "loop powered" or "two-wire" device. A DC power supply, typically 24 volts, is wired in series with the 4-20 mA output signal and the transmitter derives its operating power from this source. Loop powered devices generally consume very little power, but process designers must consider the total resistance imposed on the loop by all connected devices. The cable, unless the length is monstrous, poses a measurable but comparatively small resistance. Careful consideration should be given to the resistance imposed by receiving devices, especially if there are several in series, receiving the loop signal. The output voltage of the power supply and the maximum tolerable voltage of the connected devices will serve as limiting factors on loop instrument quantity. Where they can be applied, two-wire transmitters offer a straight forward solution for delivery of analog process measurement signals.

A "four-wire" transmitter gets its name from, you guessed it, the two pairs of wires used to provide operating power and a signal transmission path. Provided with a separate power source, possibly even 120 volts AC, this transmitter type will often be found in applications where the sensor may have power requirements that cannot be met with the limitations inherent in the loop powered device. While it may seem that the separate power supply negates the need to consider total resistance load on the signal loop, this is not the case. The signal loop still will be limited by the DC power supply that serves as the driving force of the loop.

In many cases, the question of "two-wire or four-wire" will be answered by the transmitter manufacturer. Since the two-wire scheme is a less burdensome installation, it may be the only product offering when a suitable device can be designed for an application. That said, a diligent search will probably find two and four-wire versions of transmitters for almost every application.

What are some decision making guidelines?
  • Some types of transmitters have sufficiently high power requirements that they cannot be loop powered. In this case, four-wire may be the only option.
  • For low resistance loads, use 2 wire transmitters for a simpler installation.
  • Allow some headroom in the loop resistance to accommodate at least one added receiving device in the future. For example, a temperature signal may serve as an input to a controller now, but need to service a recording device potentially added in the future.
  • Distance should not be mindlessly overlooked, but is generally not a limiting factor, as most installations would be compatible with the distance limitations for two- or four-wire device output signals.
  • When signal transmission distances become unwieldy, due to cabling costs or other factors, consider a wireless transmitter instead of a wired device.
An important aspect of applying 4-20 mA signal loops is to maintain the capability to add another receiving device to the circuit. The use of information in the form of process signals has been growing for a long time and is likely to continue. It is certainly easier to wire an additional device into an existing loop, than to install an additional sensor, transmitter, power supply, and cabling to accommodate the additional device.

Share your process measurement requirements and challenges with process instrumentation experts, leveraging your own process knowledge and experience with their product application expertise to develop complete and effective solutions.


Inside Look at Multichannel Refractometer User Interface

K Patents, globally recognized manufacturer of process refractometers for liquid analysis, offers a multichannel user interface providing connectivity for up to four refractometers. The model MI provides environmental protection and industrial computing and intelligence to deliver maximum performance and ease of use. The company provides this list of primary features.
  • High-performance, industrial computing system
  • Expandable system and connectivity for up to four (4) PR-43-G refractometers and eight (8) I/O modules
  • Environmentally sealed IP67, Type 4X (door closed), IP 66 (door open), rugged 316 stainless steel enclosure. Also for demanding field and outdoor conditions (-40−50°C, -40−122°F)
  • Prism wash diagnostics and control
  • Trend display that shows one or two graphs over a selected period of time.
  • Embedded measurement apps: The apps are small programs that give different types of measurement data and functionality
  • Modules, e.g. mA-output and mA-input module
  • 10” graphical touchscreen color display
  • 21 CFR 11 compliant user identification and management, electronic data records and data-logging, event log/audit trail.
The video provides a visual tour of the interface and behind the panel layout. Share your industrial liquid process analysis challenges with process measurement experts. Leverage your own knowledge and experience with their product application expertise to develop effective solutions.

Signal Splitter Solves Multiple Device Connection Challenge

distributed I/O modules
Selecting the right I/O modules can solve signal
transmission challenges.
Image courtesy Acromag
Industrial process measurement and control requires the transmission of signals from point to point with no significant distortion. Even with the growing prevalence of wireless signal transmission, over-wire transmission of signals is still a primary means of connecting one device to another.

In the cabled process measurement and control world, the 4 to 20 milliampere signal is generally considered the standard for transmitting analog control and measurement signals over any distance.There is an immense array of instrumentation and controllers available for use with 4-20 mA signals, so expertise in routing and delivering those signals should be part of your process measurement and control skill set.

Like just about everything else, routing 4-20 mA signals presents its own set of challenges that require some thought and planning to overcome. Electrical interference is always a concern and must be prevented from impacting the operation of measurement and control devices. Additionally, there must be sufficient power in the signal loop to accommodate the resistance load of connected devices. There are other considerations, but I'm going to focus on these two.

One scenario that can present significant issues is multiple devices requiring connection to the same signal, but with great distance between them. A simple solution can be implemented using an isolated signal splitter.

Features of these units making them an attractive, single box, solution:
  • One 4-20 ma input channel for the measuring or controlling device.
  • The input signal is retransmitted as identical isolated 4-20 ma signals
  • Galvanic isolation from input to output
  • Isolation between channels for safety and increased noise immunity. Fault in one output channel does not impact the operation of the other channels.
  • Reliable operation in industrial environments, with protection from RFI, EMI, ESD, and surges.
  • Low radiated emissions in accordance with CE requirements. 
  • DIN-rail mounting of the unit
  • Plug-in terminal blocks
If you have a very long signal loop, connecting multiple devices, consider breaking the devices into two groups that may allow for a substantially shorter cable length for each group. Connect each group to one of the isolated outputs of the splitter, giving each group of instruments the identical signal without the risks or impractically of an excessively long cable run.

There are other devices available that may combine special characteristics that solve your signal transmission and processing challenges. Contact a product specialist and discuss your existing or anticipated project requirements. Combine your process knowledge and experience with the extensive product knowledge of a professional sales engineer and produce the best possible outcome.

Instrument Specialties is Ready to Help Hurricane Impacted Partners

Industrial Instrumentation, Valves
and Municipal Equipment

Instrument Specialties is Ready to Help

As our Florida industry partners rebuild, ISI offers special emergency services for your plant. 
As we Floridians begin to recover from the damage of Hurricane Irma,  ISI Technicians & Field application support engineers, are available to you.  We have support personnel located in all major metropolitans areas including: Orlando, Miami, Ft. Myers, Tampa, Lakeland, and Jacksonville.
During September ISI will waive most emergency and expedited service fees, related to our products, for hurricane related issues. These include:
  • Technical Field Support
  • Emergency Onsite Field Support
  • Evaluation and Testing Fees
We are here for you, and ready to help get your plant up and running ASAP.
Contact Info:
Instrument Specialties Inc.:
3885 St. Johns Parkway
Sanford, FL 32771
Email: Click Here

Freezeless Control Valve

dump valve control valve for separator vessels
Model 1451 "Freezeless" Control Valve installs
with trim immersed in liquid.
Image courtesy SOR
There are almost uncountable control valve variants available in the industrial marketplace. Some have applicability over a wide range of settings, with size, materials of construction, or pressure rating being their only distinguishing factor. Others are tailored to comparatively narrow performance bands or applications, delivering specialized performance where it is needed.

SOR, global manufacturer of fluid measurement control components, fills an application niche with its "freezeless" control valve. Intended primarily for use on oil production equipment, the compact model 1451 control valve mounts directly to a separator or scrubber in a manner that places the plug and seat submerged in the process liquid. The liquid acts as a heat source to keep the valve trim from freezing.

More information is provided in the data sheet below. For best results, share your fluid measurement and control challenges with application specialists, combining your own process knowledge and experience with their product application expertise to develop and effective solution.

MSA Ultima X5000 Gas Monitor is Packed With Advances

The Ultima X5000 Gas Monitor from MSA incorporates a number of patented features, along with advanced design, that deliver superior performance and lower ownership cost for monitoring and detecting toxic and hazardous gas in industrial settings. Take two minutes and watch the video to learn more, or contact a product specialist with your application challenge for an effective solution.

Make Good Use of Technical Sales Representatives

technical sales engineers consulting with customer on project
Technical sales representatives bring outside expertise
Process and control equipment is most often sold with the support of sales engineers working for the local distributor or representative. Realizing what these specialists have to contribute, taking advantage of their knowledge and talent, will help save time and cost, contributing to a better project outcome.

Consider these contributions:

Product Knowledge: Sales engineers, by the nature of their job, are current on new products, their capabilities and their proper application. Unlike information available on the Web, sales engineers get advanced notice of product obsolescence and replacement. Also, because they are exposed to so many different types of applications and situations, sales engineers are a wealth of tacit knowledge that they readily share with their customers.

Experience: As a project engineer, you may be treading on fresh ground regarding some aspects of your current assignment. You may not have a full grasp on how to handle a particular challenge presented by a project. Call in the local sales person - there can be real benefit in connecting to a source with past exposure to your current issue.

Access: Through a technical sales engineer, you may be able to look “behind the scenes” with a particular manufacturer and garner important information not publicly available. Sales reps deal with people, making connections between customers and manufacturer's support personnel that may not normally be public facing. They make it their business to know what’s going on with products, companies, and industries.

Of course, sales engineers will be biased. Any solutions proposed are likely to be based upon the products sold by the representative. But the best sales people will share the virtues of their products openly and honestly, and even admit when they don’t have the right product. This is where the discussion, consideration and evaluation of several solutions become part of achieving the best project outcome.

As an engineer who designs or manufactures a product or process, it's highly recommended you develop a professional, mutually beneficial relationship with a technical sales expert, a problem solve. Look at a relationship with the local sales engineer as symbiotic. Their success, and your success, go hand-in-hand.

Flowserve ValveSight Diagnostic Solution for Control Valves

The video shared this week, from Flowserve, provides an overview of their ValveSight real time online diagnostic solution for use with control valves and associated actuators, positioners and controls. ValveSight enables operators to keep valves in service longer by detecting potential failures before they occur. The system provides a deep level of monitoring and diagnostic functions which are described in the video. Reducing unplanned downtime is a common goal among all facilities and plant operators. Check out the short video, and share your questions about the system with an application specialist.

Smart Control for Steam Boiler Water Level

Maintaining proper water level in a boiler is necessary for safe and efficient operation. Historically, boiler level measurement and control were accomplished with mechanical means. Today, sensor technology, electronics, and software bring improved accuracy and a host of other useful features to the water level control system.

Clark-Reliance, a globally recognized leader in level indication and control, separation and filtration for steam systems, has developed a smart boiler level indication system to enhance boiler operation. The video included below provides an illustrative overview of the system, how it works and the benefits it will bring to a new or retrofit installation.

Share your combustion and steam challenges with experienced specialists, and combine your site and project knowledge with their expertise to deliver an effective solution.

Video of Valtek Packing Subassembly

The Mark One, from the Flowserve brand Valtek, is a globe valve intended for flow control of liquids or gases across a wide range of applications. The valve design provides high positioning accuracy, repeatability and tight shutoff. A wealth of special design and construction features make the Mark One a serious contender for almost any fluid control operation.

Share your control valve and valve automation requirements and challenges with an application specialist, combining your own process knowledge and experience with their product application expertise to develop an effective solution.

Eccentric Rotary Plug Control Valve

rotary eccentric plug industrial control valve with actuator
The MaxFlo 4 eccentric rotary plug control valve
Image courtesy of Flowserve Valtek
There is a seemingly limitless array of industrial control valves, each targeted for a range of fluid applications and fortified with materials and design features specifically suited for meeting the challenges of that application range.

Flowserve, under their Valtek brand, developed a control valve that combines a number of useful design features. The MaxFlo 4 is an eccentric rotary plug valve intended for fluid control operations. The valve has some attractive design features.

  • There is no shaft extending through the flow path, leaving flow unobstructed when the valve is fully open (see the illustration in the document included below).
  • Valve trim provides tight bi-directional shutoff.
  • Metal or soft seat construction is available to accommodate a wide range of applications.
  • A variant provides flange to flange dimensions that allow the MaxFlo 4 to drop in as a replacement for standard size globe valves.
  • High Cv rating may enable use of a smaller valve, when compared to other designs.
  • Precise position control is delivered by the shaft form and plug mounting.
  • Double offset eccentric plug eliminates sliding of plug across sealing surfaces, reducing wear and required seal maintenance.
More detailed information is provided in the document provided below. There is a revealing cutaway illustration showing the mounting and movement path of the plug. Share your industrial process control valve requirements and challenges with an application specialist to get the best match of control valve to application.

Ultrasonic Flow Measurement Overview

ultrasonic flowmeter for custody transfer
One of several versions of ultrasonic flowmeter suitable
for custody transfer operations.
Courtesy Krohne
Ultrasonic flow meters measure, via sound waves inaudible to humans, the velocity of fluid flowing through a conduit. The conduit can be a recognizable closed piping run, or open channels, flumes, or chutes. The technology is predominantly applied to liquids and gases. 

There are three types of ultrasonic flow meters, differentiated by their means of measurement. An open channel flow meter derives liquid depth by computing geometrical distance, combining it with a velocity measurement and known dimensional properties of a flume or other channel. A Doppler shift flow meter reflects ultrasonic energy off sonically reflective materials and measures the frequency shift between emission and reflection to derive a fluid velocity measurement. The contrapropogating transit-time flow meter, more recognizably, the transmission flow meter. The transmission flow meter has two versions: the in-line and the clamp-on. The in-line configuration is intrusive, with flow meter hardware extending into and exposed to the measured media. A clamp-on style ultrasonic flow meter resides on the outside of the pipe, emitting and receiving the ultrasonic pulses through the pipe wall. These process measurement tools, using ultrasound technology, have the ability to measure fluid velocity and calculate volumetric, mass, and totalized flow. The use of ultrasonic flow measurement is prevalent in the oil and gas, nuclear, wastewater, pharmaceutical, and food and beverage industries. It is also employed in energy management systems as a means to measure energy demand. 

For intrusive flow meters, sensors are fitted opposite one another and alternate bouncing ultrasonic signals back and forth in the pipe, in an almost tennis-like format. In an elementary explanation, by increasing the number of sensors, engineers are able to decipher flow proportions through calculations of velocity between sensory transmissions; thereby, the flow volume can be computed. 

For externally mounted flow meters, a clamp-on device affixes the flow meter measurement elements to the pipe. One special characteristic of clamp-on flow meters is the ability to transmit ultrasonic signals through piping up to four meters in diameter, making them suitable for application in very large systems such as those found in hydroelectric or wastewater installations. The clamp-on arrangement also facilitates addition of a flow measurement point to an existing system without process interruption. 

The technology is pervasive in the processing industries, having its particular niche of applications where it excels. Proper installation is a key element in producing reliable and consistent results. Ultrasonic energy flow technology is used for custody transfer of natural gases and petroleum liquids. Custody transfer usually entails following industry, national, and government standards and regulations. Other popular applications include compressed air system monitoring and energy usage metering. 

Ultrasonic flow meters, with no moving parts, are comparatively low maintenance and self-diagnosing. Temperature and pressure measurements are needed to calculate mass flow of gases. When measuring liquid mass flow in pipes, it is generally necessary for the pipe cross section to be media filled in order to obtain reliable results. 

Whatever your flow measurement challenge, share it with a process measurement specialist. Combine your process knowledge with their product application expertise to develop effective solutions.

Medium Voltage Drives With Reduced Footprint

variable frequency drive VFD medium voltage
Medium voltage variable frequency drive
Courtesy Siemens
Floor space, a resource most facilities managers dole out sparingly. There seldom seems to be enough for all the equipment and operations that comprise a modern industrial operation.

Siemens, globally recognized leader in the design and manufacture of variable frequency drives, offers its latest version of the Perfect Harmony GH180 variable frequency drive to reduce the required footprint by up to one third. The drive includes a transformer cabinet, cell cabinet, and cooling cabinet. Programming has been simplified and reduced, along with component count and required connections. A number of other enhancements increase reliability and reduce the need for maintenance. The units are available for medium voltage applications and come in air-cooled and water-cooled variants.

Share your motor drive requirements with product application specialists, combining your first hand facility knowledge and experience with their product application expertise to develop effective solutions.

Open Channel Flow Measurement Combines Laser and Ultrasonic Technologies

Combining Doppler laser velocity measurement with ultrasonic level measurement enables the Teledyne ISCO LaserFlow™ sensor to provide reliable and accurate flow measurement in open channel applications.

Ultrasonic technology is used to determine the depth of the liquid stream and identify a sub-surface point at which to measure velocity. After focusing the sensor's laser on the target, Doppler shift in the returned light is used to calculate the flow velocity. A flow computer combines the information to produce useful flow data.

The video provides detail on the application and features of the LaserFlow™ sensor. Share your flow measurement requirements and challenges with instrumentation specialists, combining your own process knowledge and experience with their product application expertise to develop effective solutions.

New Electronic Pressure Switch With Continuous Output Signal

loop powered electronic pressure switch with continuous output
The new 805QS electronic pressure switch
Courtesy SOR, Inc.
SOR now has an enhanced version of their popular pressure transmitter, model 805PT. The new 805QS provides a continuous output signal corresponding to pressure, but also incorporates a failsafe adjustable pressure switch into the same device. The switch can be configured in the factory or field to operate in one of three ways:
  • Switch is closed when pressure is above a low setpoint and below a high setpoint. This is referred to as a "window" setting.
  • Switch is closed when pressure is above a setpoint.
  • Switch is closed when pressure is below a setpoint.
In all variants, the switch will open on loss of power. The loop powered unit is designed so that the switch and output signal operate independently. Other features include a five millisecond response time, full range temperature compensation, and global certifications.

Learn more from the video, and share your process instrumentation and control challenges with application experts. Combine your own process knowledge and experience with their product application expertise to develop an effective solution.

Continuous Liquid Level Measurement Technologies Used in Industry

differential pressure transmitter for industrial process control
Industrial differential pressure transmitter
Courtesy Krohne
Although continuous level measurement technologies have the ability to quantify applications for bulk solids, slurries, and granular materials, this article will focus on level measurement technologies applied to liquid level measurement utilized in process control. A distinction should be made between continuous level measurement and point level measurement. Point level measurement acts like a switch, changing state when a single level condition is achieved. Called “transmitters,” continuous liquid level measurement devices employ technologies ranging from hydrostatics to magnetostriction, providing uninterrupted signals that indicate the level of liquid in a vessel, tank, or other container.

Hydrostatic devices focus on the equilibrium of dynamic and static liquids. There are three main types of hydrostatic transmitters: 1) displacer, 2) bubbler, and 3) differential pressure.

The displacer transmitters utilize a float placed within the liquid container. With its buoyancy characterized to the liquid and the application, the float, a connecting stem, and a range spring or similar counterbalance represents the liquid level in terms of the movement of the displacer (float). The displacement, or movement, of the assembly is converted into an electric signal for use by the monitoring and control system.

Bubbler transmitters are used for processing vessels that operate at atmospheric pressure. This method introduces a purge gas or an inert gas, e.g. air or dry nitrogen, into a tube extending into the liquid vessel. Precise measurement of the pressure exerted on the gas in the dip tube by the liquid in the tank is used to determine the height of the liquid.

Differential pressure (DP) transmitters rely directly on, in a basic explanation, the pressure difference between the bottom and top of the container. Precise pressure measurement is used to determine the height of the liquid in the tank. One of the most advantageous aspects of DP transmitters is that they can be used in pressurized containers.

Other examples of level transmitter technologies which are not hydrostatic devices include magnetostrictive, capacitance, ultrasonic, laser, and radar.

In magnetostrictive level transmitters the measuring device, a float, has a magnet that creates a magnetic field around a wire enclosed in a tube. Electrical pulses sent down the wire by the transmitter head produce a torsional wave related to the position of the float, which moves with changes in liquid surface level. The transit time of the torsion wave back to the sensing head is measured and the depth of the liquid, as indicated by the float position, can be determined.

Capacitance transmitters are best applied to liquids that have high dielectric constants. Essentially, changes in the capacitance of the sensor / tank / liquid assembly will vary proportionately with the liquid level. The change in capacitance is measured and converted to an appropriate electrical signal.

Ultrasonic level transmitters emit ultrasonic energy from the top of the vessel toward the liquid. The emissions are reflected by the liquid surface and them time required for the signal to return to the source is used to determine the distance to the liquid surface.

Laser level transmitters operate similarly to an ultrasonic level transmitter. However, instead of using ultrasound signals, they use pulses of light.

Radar level transmitters involve microwaves emitting downward from the top of the container to the liquid’s surface. The measured time for receipt of a return sign reflecting off the liquid surface enables calculation of the distance from the sensor to the liquid surface.

The precise measurement of transmit time for a wave or pulse of energy is employed in several of the technologies, the measurement of pressure in others. Each technology has a set of attributes making it an advantageous selection for a particular range of applications. Various manufacturers offer modified or enhanced versions of the basic measurement technologies to provide performance or cost benefits for ranges of applications. Share your liquid level measurement challenges with an application expert, combining you process knowledge with their product application expertise to develop effective solutions.

Hot Tap Removal of Insertion Magmeter

This short video, produced by Seametrics, outlines the procedure for removal of their insertion magnetic flow sensor from an active line. The flow sensor has been installed in conjunction with a full port ball valve that allows isolation of the sensor from the pipe once the sensor has been properly positioned. The capability to remove the sensor for inspection or other operations without disturbing the contained process can be advantageous to certain applications.

Magnetic flow measurement instruments are effective in applications with sufficiently conductive liquids. A magnetic field is produced by the sensor. As liquid flows through the magnetic field, a small electric current is produced. The polarity of the magnetic field is rapidly reversed by the unit electronics, and the resulting output signal from the sensing unit is a rapid pulse, proportional to the flow rate. The pulse can be counted by electronic devices and used for monitoring, totalizing, or control. The signal is also easily converted to a 4-20 mA or other analog signal for transmission to other instruments or devices.

Share your flow measurement requirements and challenges with process measurement instrumentation specialists. The combination of your own process knowledge and experience with their product application expertise will foster the development of effective solutions.

In-Situ, Inc. - Water Quality Instrumentation

In-Situ manufactures instruments for measuring water quality and quantity throughout industrial, commercial, institutional, and municipal settings. Watch the video to see broad range of scientific instruments designed and manufactured by the company for laboratory, process, and field use.

Get more detailed information, or share you water quality measurement challenges with a product application specialist.

Rotork Instruments Brands Join ISI Technical Group Product Portfolio

air line filter regulator stainless steel high pressure
Midland brand air line filter regulator
Courtesy Rotork Instruments
ISI Tech Group now handles a large complement of the Rotork Instruments brand family throughout the Florida and South Georgia area. A number of well recognized brand names have been incorporated into the Rotork Instruments group of products in recent years and ISI now handles four of them.

Midland is a specialist manufacturer of stainless steel large flow air service equipment. Purpose specific, manufactured solutions for filtration and regulation of compressed air and gases is the specialty of the brand. Products include filters and regulators, poppet valves, spool valves, air pressure switches, flow regulators, and a host of specialized ancillaries that fill out a complete system installation.

The Fairchild brand, which has been on the roster of ISI Tech Group products for some time, offers a wide selection of electro-pneumatic transducers, pressure regulators, pneumatic relays, volume boosters, filters and accessories for process machine tool, robotic and other industrial applications. Products are available with designs to suit all environments, including hazardous areas.

industrial solenoid valves
M&M industrial solenoid valves
Courtesy Rotork Instruments
M&M International is also a Rotork Instruments brand. M&M solenoid valves are manufactured with high quality materials and to rigorous standards to deliver durable performance and high reliability. Robust construction makes these valves well suited for industrial applications. A choice of seal materials provides wide fluid compatibility. Products include general purpose solenoid valves, air actuated piston valves, automatic drain valves, and accessory products

needle valve block and bleed manifold
Block and bleed needle valve assembly
Courtesy Rotork Instruments
Bifold, another Rotork Instruments brand, manufactures medium pressure instrumentation ball valves, needle valves, fittings, manifolds, and relief valves for applications with pressure up to 20,000 psi.

This expanded product offering empowers the process measurement and control specialists at ISI Tech Group to better serve the diverse requirements of their customer base. Share your automation and process control challenges with experts, combining your own knowledge and experience with their product application expertise to develop effective solutions.

New Company Logo for Instrument Specialties

Instrument Specialties Inc. (ISI), is a long-standing, premier manufacturer's representative and distributor of industrial instrumentation in the Georgia and Florida areas of the US. The company has recently changed its logo, trade name, and website URL. We wanted to share them with you here.

logos for Instrumentation Specialties Incorporated

The company is the same, but the new logo and trade name of ISI Technical Group will be used going forward. There is also a new website address.
Be sure not to tack ".com" onto the end of what is shown above. Try it out.

Share your process instrumentation and control challenges with the specialists at ISI Technical Group. Combining your own process knowledge and experience with their product application expertise will yield an effective solution.

Purging Differential Pressure Sensor Lines

differential pressure transmitter Krohne Optibar
Differential Pressure Transmitter
Courtesy Krohne
In a fluid system, differential pressure measurement can be utilized in conjunction with a known restrictive element in the flow path to produce a flow measurement. Manufacturers of process measurement and control apparatus often produce application notes that reflect their experience or knowledge about specific circumstances that may create problems for users and operators. The application notes outline the circumstances that create the potential for trouble, then go on to show a method of prevention, mitigation, or elimination of the problem condition.

Brooks Instrument, globally recognized innovator in precision measurement and control of flow and pressure, has produced an application note that deals with differential pressure transmitter sensor lines and how to prevent them from being fouled by accumulation of media residue. The application note is included below and also appears in the Brooks Instrument blog.

Share your process measurement challenges and requirements with product application specialists, combining your own process knowledge and experience with their product application expertise to develop effective solutions.

Innovative Boiler Water Level Gauge Delivers High Visibility

The Simpliport boiler water level gauge provides the type of performance always wanted by operators. It is visible from great distance at angles up to 180 degrees. The brightly illuminated display clearly shows what portion of the boiler contains water and what portion contains steam.

The short video provides a good demonstration. More information is available from steam system specialists. Share your combustion and steam system requirements and challenges with experts, combining your own knowledge and experience with their product application expertise to develop effective solutions.

Power System Surge Protection Device

surge protective device
Line Surge Protective Device
Courtesy Dehn, Inc.
Investments of time and financial resources to operate any business process can have their yield crushed in the blink of an eye by power system anomalies. Businesses and processes run on electric power. Greater levels of IT complexity, process instrumentation, or other electrical equipment generally bring higher levels of exposure to power line surges that can bring unexpected downtime or equipment damage to a going concern.

Prevention through protection is the only available course of action for hardening facilities to the potentially damaging effects of line surges. Dehn, Inc. manufactures products that provide solutions for lightning and surge related problems. Surge protectors and lightning current arrestors, available as compact DIN rail mounted units, function as protective devices for motors, IT equipment, process controls, and instrumentation.

The video below provides a view of how the protective devices function. Without a protection plan in place, any facility is exposed to potential damage. Share your plans and challenges with a product application specialist, combining your facilities knowledge with their product application expertise to develop an effective solution.

Control Valve Flow Characteristics

industrial control valve with actuator and positioner
Industrial Control Valve
Courtesy Flowserve - Valtek
Flow characteristics, the relationship between flow coefficient and valve stroke, has been a subject of considerable debate. Many valve types, such as butterfly, eccentric disk and ball valves, have an inherent characteristic which cannot be changed (except with characterizable positioner cams). Flow characteristics of globe valves can be determined by the shape of the plug head.

The three most common types of flow characteristics are quick opening, equal percentage and linear. The adjacent figure shows the ideal characteristic curve for each. These characteristics can be approximated by contouring the plug. However, inasmuch as there are body effects and other uncontrollable factors, plus the need for maximizing the flow capacity for a particular valve, the real curves often deviate considerably from these ideals. When a constant pressure drop is maintained across the valve, the characteristic of the valve alone controls the flow; this characteristic is referred to as the “inherent flow characteristic.” “Installed characteristics” include both the valve and pipeline effects. The difference can best be understood by examining an entire system.

graph of control valve flow properties
Control valve flow properties
Courtesy Flowserve - Valtek

Equal Percentage

Equal percentage is the characteristic most commonly used in process control. The change in flow per unit of valve stroke is directly proportional to the flow occurring just before the change is made. While the flow characteristic of the valve itself may be equal percentage, most control loops will produce an installed characteristic approaching linear when the overall system pressure drop is large relative to that across the valve.


An inherently linear characteristic produces equal changes in flow per unit of valve stroke regardless of plug position. Linear plugs are used on those systems where the valve pressure drop is a major portion of the total system pressure drop.

Quick Open

Quick open plugs are used for on-off applications designed to produce maximum flow quickly.

This information provided courtesy of Flowserve Valtek. Share your control valve requirements and challenges with a valve specialist, combining your own process knowledge and experience with their product application expertise to develop effective solutions.

Water Quality Analysis – Constituent Survey Part 3

silicon dioxide crystals quartz mineral
Silicon dioxide crystals
What we know as “water” can consist of many non-H2O components in addition to pure water. This three part series has touched on some of the constituents of water that are of interest to various industrial processors. The first installment reviewed dissolved oxygen and chloride. The second article covered sulfates, sodium, and ammonia.

To conclude the three part series on water quality analysis in process control related industrial applications we examine silica, another element which in sufficient quantities can become a confounding variable in water for industrial use. In natural settings, silica, or silicon dioxide, is a plentiful compound. Its presence in water provides a basis for some corrosion-inhibiting products, as well as conditioners and detergents. Problems arise, however, when high concentrates of silica complicate industrial processes which are not designed to accommodate elevated levels. Specifically, silica is capable of disrupting processes related to boilers and turbines. In environments involving high temperature, elevated pressure, or both, silica can form crystalline deposits on machinery surfaces. This inhibits the operation of turbines and also interferes with heat transfer. These deposits can result in many complications, ranging through process disruption, decreased efficiency, and resources being expended for repairs.

The silica content in water used in potentially affected processes needs to be sufficiently low in order to maintain rated function and performance. Silica analyzers provide continuous measurement and monitoring of silica levels. The analyzers detect and allow mitigation of silica in the initial stages of raw material acquisition or introduction to prevent undue disruption of the process. Additionally, a technique called power steam quality monitoring allows for the aforementioned turbine-specific inhibition – related to silica conglomerates reducing efficacy and physical movement – to be curtailed without much issue. The feedwater filtration couples with a low maintenance requirement, resulting in reduced downtime of analytic sequences and a bit of increased peace of mind for the technical operator.

While silica and the other compounds mentioned in this series are naturally occurring, the support systems in place to expertly control the quality of water is the most basic requirement for harvesting one of the earth’s most precious resources for use. As a matter of fact, the identification and control of compounds in water – both entering the industrial process and exiting the industrial process – demonstrates key tenets of process control fundamentals: precision, accuracy, durability, and technological excellence paired with ingenuity to create the best outcome not just one time, but each time.

Share your water quality analysis questions, requirements, or challenges with application specialists, combining your own process knowledge with their product application expertise to develop effective solutions.

Water Quality Analysis - Constituent Survey (Part 2)

water drop symbolizing industrial pure water and wastewater
Water is a vital part of many industrial processes
It would be difficult to understate the role and importance of water in industrial processing, even our own biological existence. In the first installment of this series, the roles of dissolved oxygen and chlorides were covered.

Continuing the examination of water quality monitoring in municipal and industrial processes, another key variable which requires monitoring for industrial water use is sulfate. Sulfate is a combination of sulfur and oxygen, salts of sulfuric acid. Similarly to chlorides, they can impact water utilization processes due to their capability for corrosion. The power generation industry is particularly attuned to the role of sulfates in their steam cycle, as should be any boiler operator. Minerals can concentrate in steam drums and accelerate corrosion. Thanks to advancements in monitoring technology, instruments are available which monitor for both chlorides (covered in the previous installment in this series) and sulfates with minimal supervision needed by the operator, ensuring accurate detection of constituent levels outside of an acceptable range. Ionic separation technologies precisely appraise the amount of sulfate ions in the stream, allowing for continuous evaluation and for corrective action to be taken early-on, avoiding expensive repairs and downtime.

Another substance worthy of measurement and monitoring in process water is sodium. Pure water production equipment, specifically cation exchange units, can be performance monitored with an online sodium analyzer. Output from the cation bed containing sodium, an indication of deteriorating performance, can be diverted and the bed regenerated. Steam production and power generation operations also benefit from sodium monitoring in an effort to combat corrosion in turbines, steam tubes, and other components. Sodium analyzers are very sensitive, able to detect trace levels.

Ammonia is comprised of nitrogen and hydrogen and, while colorless, carries a distinct odor. Industries such as agriculture utilize ammonia for fertilizing purposes, and many other specializations, including food processing, chemical synthesis, and metal finishing, utilize ammonia for their procedural and product-oriented needs. An essential understanding of ammonia, however, includes the fact that the chemical is deadly to many forms of aquatic life. Removing ammonia from industrial wastewater is a processing burden of many industries due to the environmental toxicity.

Methods for removing ammonia from wastewater include a biological treatment method called ‘conventional activated sludge’, aeration, sequencing batch reactor, and ion exchange. Several methods exist for in-line or sample based measurement of ammonia concentration in water. Each has particular procedures, dependencies, and limitations which must be considered for each application in order to put the most useful measurement method into operation.

As water is an essential part of almost every facet of human endeavor and the environment in which we all dwell, the study and application of related analytics is an important component of many water based processes. The variety of compounds which can be considered contaminants or harmful elements when dissolved or contained in water presents multiple challenges for engineers and process operators.

Share your water quality analysis requirements and challenges with an analytical instrumentation specialist, combining your own process knowledge with their product application expertise to develop effective solutions.

Water Quality Analysis – Constituent Survey (Part 1)

wastewater treatment plant
Wastewater Treatment Plant
Of all the raw materials available for human consumption – aside from the air we breathe – the most vital component of life on earth is water. In addition to the global need for humans to drink water in order to survive, the use of water is essential in a myriad of industries relating to process control. Whether the goal is the production or monitoring of pure water for industrial use, or the processing of wastewater, the ability to measure the presence and level of certain chemical constituents of water is necessary for success.

In order to use water properly, industrial professionals combine state of the art analyzers with technical expertise to evaluate water quality for use or disposal. Two essential values of process control are ensuring elements of a control system are accurate and secure, and, furthermore, that they are accurate and secure for each product every time. By properly vetting water in industry, engineers and other personnel in fields such as pharmaceuticals, chemical, food & beverage, brewing, power, and microelectronics are able to maintain standards of production excellence and conform with regulatory requirements related to water quality.

The amount of dissolved oxygen present in water can correlate with the degree of movement at an air-water interface, also being impacted by pressure, temperature, and salinity. Excessive or deficient dissolved oxygen levels in industrial process waters may have an impact on process performance or end product quality. Likely, the most common application for dissolved oxygen measurement is in the evaluation of wastewater for biological oxygen demand. The primary function of dissolved oxygen in wastewater is to enable and enhance the oxidation of organic material by aerobic bacteria, a necessary step in treatment.

To measure dissolved oxygen, specialized sensors and companion instruments are employed that require careful maintenance and trained technical operators. The level of measurement precision varies depending on the industry employing the technology, with numerous applications also being found in the food & beverage and pharmaceutical industries. In-line continuous measurement is used in wastewater processing to determine if the dissolved oxygen remains in a range that supports the bacteria necessary for biodegradation.

Chloride concentration in wastewater is strictly regulated. Industrial and commercial operation effluent can be regulated with respect to allowable chloride content. While commonly found in both streams and wastewater, chlorides, in large amounts, can present challenges to water utilization or processing facilities. Chloride levels impact corrosion, conductivity, and taste (for industries in which such a variable is paramount). In a process system, having an essential component marred due to elevated quantities of a substance could reverberate into any end-product being manufactured. Chloride analyzers, some of which can also detect and monitor other water characteristics, serve as important tools for water consuming facilities to meet regulatory standards for effluent discharge or internal quality standards for recycling.

There are other constituents of what we refer to as “water” that are subject to measurement and monitoring for a range of institutional, industrial, and municipal applications. Those will be explored in the next part of this article series. Share your water analysis and treatment challenges with application experts, combining your own process expertise with their product knowledge to develop effective solutions.