Showing posts with label process control. Show all posts
Showing posts with label process control. Show all posts

Monday, September 11, 2017

Industrial Level Measurement

Point level
Point level switch (FCI)
In many industrial processes, the measurement of level is critical. Depending on the nature of the material being measured, this can be a simple or complex task. Several different technologies for sensing level are briefly explained here.

Direct Method

The direct method of level measurement calculates levels instantly using physical properties, like buoyancy and fluid motion. Beginning from the simplest, the following are the three main types:
  • Sight glass type
  • Float type
  • Magnetic level gauge
Sight glass measures liquid in tanks. A scaled glass tube with metallic covering it is attached to the top and bottom edges of the tank and, as the liquid moves up and down, the level in the tube fluctuates in the same way.

Float type measurement makes use of buoyancy: a float device follows the liquid level while sitting atop it. As the liquid moves so does the float device; a cable, attached to the top of the device, is rigged to a calibrated scale with a pointer in the middle. The up and down movements pull the string which pulls the pointer, thus showing where the liquid level is.

 A magnetic level gauge looks like a thick thermometer and is attached to the end of a vertical chamber. This vertical chamber contains a magnetic float, a permanent magnet, which floats on the top of the liquid level in the tank.

There is one more thing also attached to the outside of the tank: an indicating scale with small metallic strips. These strips are white and red sided flippers, rotating 180° whenever the float magnet attracts them while passing over. Whenever the float magnet is above, the strips will flip red side up, indicating the tank’s level.

Indirect Method

In the indirect method of level measurement, the level of a liquid is calculated by a variable that changes according to the level. There are four main types:

  • Pressure gauge type
  • Differential pressure type
  • Ultrasonic type
  • Radar type
The pressure gauge is a simple method; a pressure gauge is attached near the bottom of tank and pressure, exerted by the tank, is calculated. The gauge changes in time with the tank’s liquid pressure, and the measurement is made according to the height of the liquid.

Radiometric Level
Radiometric Level (RONAN)
The differential pressure method (DP method) is another widely used method in industry. This method requires a DP transmitter and a port; these two parts are connected to the external tank at opposite ends. The differential pressure in the tank is measured between the DP transmitter at the bottom and the port at the top; the output of the differential pressure calculated by the DP transmitter is proportional to the liquid level. The more liquid in the tank, the more pressure is at the transmitter; the less liquid in the tank, the more pressure at the port.

The ultrasonic method is a no-contact type. A transmitter is mounted atop the tank and ultrasonic sound waves are sent from the transmitter toward the surface of the measured fluid. An echo of the wave is calculated and the time it took for the wave to reach its end goal from the transmitter becomes its distance. The time of the length of the distance is then calibrated in terms of the level of process material.

The radar method is a no-contact type and it uses electromagnetic waves. Electromagnetic waves are sent through a transmitter to the surface of the measured material. There is a receiver toward the bottom of the tank which takes a portion of the energy sent from the wave and then reflects it back toward the surface of the medium. The reflected energy then becomes calibrated into level measurement.

Industrial level control requires deep knowledge and understanding of many process variables, such as media compatibility, interfaces, head pressures, material densities, and mechanical considerations. It's always recommended that an experienced consultant be involved with the selection and implementation of any industrial level device.

Saturday, July 22, 2017

Fieldbus Equipped Instrumentation - Part One

Autonomous control and digital instrumentation are two capabilities enabling highly precise or complex execution of process control functions. FOUNDATION fieldbus instrumentation elevates the level of control afforded to digital field instrumentation where, instead of only communicating with each other, instruments involved in particular process control systems can independently facilitate algorithms typically reserved for instruments solely dedicated to controlling other instruments. Fieldbus capable instrumentation has become the standard instrumentation for many process industry installations due to the fact the FOUNDATION design principle streamlines process systems. A large contributor to FOUNDATION's success has been faster installation as opposed to operational controllers which do not feature the fieldbus configuration. Newer process companies, or process control professionals seeking to establish a new system, have gravitated towards fieldbus due to the combined advantages of system conciseness and ease of implementation.

In a typical digital control system, dedicated controllers communicate with field instrumentation (the HART protocol is a prime example of digital communication at work in the industry). The host system controls configuration of instruments and serves as a central hub where all relevant control decisions are made from a single dedicated controller. Typically, these networks connect controllers and field devices through coupling devices and other buses which streamline many different instruments into a complete system.

FOUNDATION fieldbus approaches the same network scheme with an important difference. Whereas in a legacy or more conventional system, either algorithmic or manual decisions would need to be implemented via the dedicated system level controllers, instruments utilizing FOUNDATION fieldbus architecture can execute control algorithms at the local device level. The dedicated controller hub is still present, so that operators can view and monitor the entire network concurrently and make status changes. Algorithmic execution of control functions becomes entirely device reliant thanks to the FOUNDATION protocol. Additionally, even though FOUNDATION implements an advanced configuration, some operators use the capabilities introduced in the fieldbus upgrade to implement specific algorithms via each device while concurrently maintaining algorithms in the central controller. This dual algorithmic configuration allows for several advantages, including the ability for increased system precision.

Since individual devices in the control process are calibrated and able to execute their own control functions, issues in the process with particular devices can be isolated and dealt with in a more specified manner by technicians using the instruments in the field. The central operator retains the capacity to use the control hub to alter and direct the control system.

For more information contact Flow-Tech in Maryland at 410-666-3200; in Virginia at 804-752-3450, or visit http://www.flowtechonline.com.

Watch for Part Two of this series to be posted soon.

Monday, June 12, 2017

New Product Alert: Release 4 of the SMARTDAC+ GX/GP Series Paperless Recorders and GM Series Data Acquisition System

SMARTDAC+
Yokogawa Electric Corporation announced it's Release 4 of the SMARTDAC+® GX series panel-mount type paperless recorder, GP series portable paperless recorder, and GM series data acquisition system.

With this latest release, new modules are provided to expand the range of applications possible with SMARTDAC+ systems and improve user convenience. New functions include sampling intervals as short as 1 millisecond and the control and monitoring of up to 20 loops.

Overview


Recorders and data acquisition systems (data loggers) are used on production lines and at product development facilities in a variety of industries to acquire, display, and record data on temperature, voltage, current, flow rate, pressure, and other variables. Yokogawa offers a wide range of such products, and is one of the world’s top manufacturers of recorders. Since releasing the SMARTDAC+ data acquisition and control system in 2012, Yokogawa has continued to strengthen it by coming out with a variety of recorders and data acquisition devices that meet market needs and comply with industry-specific requirements and standards.

With this release, Yokogawa provides new modules with strengthened functions that meet customer needs for the acquisition and analysis of detailed data from evaluation tests. These modules decrease the cost of introducing a control application by eliminating the need for the purchase of additional equipment.

Enhancements

The functional enhancements available with Release 4 are as follows:
  1. High-speed analog input module for high-speed sampling
    To improve the safety of electric devices such as the rechargeable batteries used in everything from automobiles to mobile devices, evaluation tests must be conducted to acquire and analyze detailed performance data. For this purpose, sampling at intervals as short as 1 millisecond is desirable. However, this normally requires an expensive, high-performance measuring instrument. When the new high-speed analog input module, a SMARTDAC+ system can sample data at intervals as brief as 1 millisecond, which is 1/100th that of any preceding Yokogawa product. This is suitable for such high performance applications such as measurement of the transient current in rechargeable batteries to vibration in power plant turbines. A dual interval function has also been added that enables the SMARTDAC+ to efficiently and simultaneously collect data on slowly changing signals (e.g., temperature) and quickly changing signals (e.g., pressure and vibration).
  2. PID control module for control function
    In applications that need both control and recording, such as controlling the temperature of an industrial furnace or the dosage process at a water treatment plant, there is a need for systems that do not require engineering and can be quickly and easily commissioned. In a typical control and monitoring application, a separate recorder and controller is required to control temperature, flow rate and pressure. At the same time, a data acquisition station must communicate with the controller to ensure data is being capture and recorded. It is time consuming and oftentimes confusing, to ensure the controller and the data acquisition station is communicating seamlessly. By combining continuous recording function of the SMARTDAC+ and PID control module into a single platform, customers can now seamlessly control and record critical process data in one system. The SMARTDAC+ can control, monitor and record up to 20 loops. Each PID control module comes with 2 analog inputs, 2 analog outputs, 8 digital inputs and 8 digital outputs.
  3. Four-wire RTD/resistance module for precise temperature measurement
    While three-wire RTDs are widely used in many fields such as research institutes to manufacturing, some applications require higher level of precision and accuracy that is only possible with 4-wire RTDs. A 4-wire RTD is the sensor of choice for laboratory applications where accuracy, precision, and repeatability are extremely important. To satisfy this need, Yokogawa has released a 4-wire RTD/resistance module for the SMARTDAC+
Target Markets

GX series: Production of iron and steel, petrochemicals, chemicals, pulp and paper, foods, pharmaceuticals, and electrical equipment/electronics; water supply and wastewater treatment facilities
GP series: Development of home appliances, automobiles, semiconductors, and energy-related technologies; universities; research institutes
GM series: Both of the above target markets

To download brochures, visit this link. For more information inVirginia, contact Flow-Tech at 804-752-3450 or visit http://www.flowtechonline.com.

Sunday, May 7, 2017

FCI ST100 and ST110 Thermal Dispersion Flow Meters

FCI flow meters
FCI flow meters
FCI flow meters operate on the principle of thermal dispersion. The flow meter circuitry measures the temperature differential between a heated and a non-heated sensors.  The greater the mass flow rate, the less temperature differential between the two sensors.

FCI flow meters
FCI ST100
The ST100 series transmitter is unsurpassed in meeting your current and future need for outputs, process information and communications. Whether your output needs are traditional 4-20 mA analog, frequency/pulse, alarm relays or advanced digital bus communications such as HART, FOUNDATION Fieldbus, PROFIBUS, or Modbus, ST100 has you covered. ST100's bus communications have been certified by and are registered devices with HART and Foundation Fieldbus. In addition, Emerson Process (Delta V), Yokogawa and ABB (800xA) have tested and verified ST100 Series' FOUNDATION Fieldbus interoperability with their systems. Should you ever need to change or upgrade, ST100 can be converted to any of these outputs with a simple card change in the field.

FCI flow meters
FCI ST110
Many alternative flow meters require periodic removal from service verify calibration which can be expensive if the flow meter needs to be sent back to the factory. The FCI ST110 is capable of calibration verification without being taken out of service.

ST100 flow meters offer the following advantages over other gas flow technologies:
  • Three, 4-20 mA outputs for flow, temperature, and/or optional pressure
  • Very high turn down ratios - up to 1000:1
  • Digital communication options of Foundation Fieldbus, PROFIBUS,  HART or Modbus 
  • The data logging via removable SD card
Ruggedness, accuracy, and superior quality made FCI the leader in thermal dispersion mass flow meters, flow switches and level switches for industrial process measurement applications. FCI air and gas flow meters are applied from small dosing lines to the largest stacks. For more information about FCI in Maryland or Virginia, visit http://www.flowtechonline.com or call 410-666-3200.

Tuesday, March 28, 2017

Tuesday, March 21, 2017

Industrial Temperature Control Basics

Process Controllers
Process Controllers used with thermocouples or RTDs
for temperature control (courtesy of Yokogawa)
The regulation of temperature is a common operation throughout many facets of modern life. Environmental control in commercial, industrial, and institutional buildings, even residential spaces, uses the regulation of temperature as the primary measure of successful operation. There are also countless applications for the control of temperature found throughout manufacturing, processing, and research. Everywhere that temperature needs to be regulated, a device or method is needed that will control the delivery of a heating or cooling means.

For industrial process applications, the temperature control function is found in two basic forms. It can reside as an operational feature within a programmable logic controller or other centralized process control device or system. Another form is a standalone process temperature controller, with self-contained input, output, processing, and user interface. Depending upon the needs of the application, one may have an advantage over the other. The evolution of both forms, integrated and standalone, has resulted in each offering consistently greater levels of functionality.

There are two basic means of temperature control, regardless of the actual device used. Open loop control delivers a predetermined amount of output action without regard to the process condition. Its simplicity makes open loop control economical. Best applications for this type of control action are processes that are well understood and that can tolerate a potentially wide variation in temperature. A change in the process condition will not be detected, or responded to, by open loop control. The second temperature control method, and the one most employed for industrial process control, is closed loop.

Closed loop control relies on an input that represents the process condition, an algorithm or internal mechanical means to produce an output action related to the process condition, and some type of output device that delivers the output action. Closed loop controllers require less process knowledge on the part of the operator than open loop to regulate temperature. The controllers rely on the internal processing and comparison of input (process temperature) to a setpoint value. The difference between the two is the deviation or error.  Generally, a greater error will produce a greater change in the output of the controller, delivering more heating or cooling to the process and driving the process temperature toward the setpoint.

The current product offering for standalone closed loop temperature controllers ranges from very simple on/off regulators to highly developed products with multiple inputs and outputs, as well as many auxiliary functions and communications. The range of product features almost assures a unit is available for every application. Evaluating the staggering range of products available and producing a good match between process requirements and product capabilities can be facilitated by reaching out to a process control products specialist. Combine your own process knowledge and experience with their product application expertise to develop effective solution options.

Monday, January 30, 2017

Operating Principles and Application of Vortex Flowmeters

vortex flowmeter
Vortex flowmeter
(courtesy of Yokogawa)
To an untrained ear, the term "vortex flowmeter" may conjure futuristic, potentially Star Wars inspired images of a hugely advanced machine meant for opening channels in warp-space. In reality, vortex flowmeters are application specific, industrial grade instruments designed to measure what may be the most important element of a fluid process control operation: flow rate.

Vortex flowmeters operate based on a scientific principle called the von Karman effect, which generally states that a fluid flow will alternately shed vortices when passing by a solid body. "Vortices" is the plural form of vortex, which is best described as a whirling mass, notably one in which suction forces operate, such as a whirlpool. Detecting the presence of the vortices and determining the frequency of their occurrence is used to provide an indication of fluid velocity. The velocity value can be combined with temperature, pressure, or density information to develop a mass flow calculation. Vortex flowmeters are reliable, with no moving parts, serving as a useful tool in the measurement of liquid, gas, and steam flow.

While different fluids present unique challenges when applying flowmeters, stream is considered one of the more difficult to measure due to its pressure, temperature, and potential mixture of liquid and vapor in the same line. Multiple types of steam, including wet steam, saturated steam, and superheated steam, are utilized in process plants and commercial installations, and are often related to power or heat transfer. Several of the currently available flow measurement technologies are not well suited for steam flow applications, leaving vortex flowmeters as something of a keystone in steam flow measurement.

Vortex flowmeter
Vortex flowmeter
(courtesy of Yokogawa)
Rangeability, defined as a ratio of maximum to minimum flow, is an important consideration for any measurement instrument, indicating its ability to measure over a range of conditions. Vortex flowmeter instruments generally exhibit wide rangeability, one of the positive aspects of the technology and vortex based instruments.

The advantages of the vortex flowmeter, in addition to the aforementioned rangeability and steam-specific implementation, include available accuracy of 1%, a linear output, and a lack of moving parts. It is necessary for the pipe containing the measured fluid to be completely filled in order to obtain useful measurements.

Applications where the technology may face hurdles include flows of slurries or high viscosity liquids. These can prove unsuitable for measurement by the vortex flowmeter because they may not exhibit a suitable degree of the von Karman effect to facilitate accurate measurement. Flow measurements can be adversely impacted by pulsating flow, where differences in pressure from the relationship between two or more compressors or pumps in a system results in irregular fluid flow.

When properly applied, the vortex flowmeter is a reliable and low maintenance tool for measuring fluid flow. Frequently, vortex flow velocity measurement will be incorporated with the measurement of temperature and pressure in an instrument referred to as a multivariable flowmeter, used to develop a complete measurement set for calculating mass flow.

Whatever your flow measurement challenges, share them with a flow instrument specialist, combining your process knowledge with their product and technology expertise to develop effective solutions.

Wednesday, December 28, 2016

DCS Extension or Upgrade Can Boost Process Performance

automated factory
Process automation and control
Industrial control systems, regardless of their type or brand, command first line attention in the operation of a process. After all, with the purpose of a centralized control system being the integration and coordination of all process functions, the control system runs just about everything. Over time, all systems begin to lose some of their value. Causes can include:

  • New technology, regulation, or another factor renders all or part of existing system obsolete.
  • Deterioration of operating components from use.
  • Procedural requirements that are overly burdensome in the current business environment.
  • Outright failure of portions of the system due to unforeseen events.
  • Abandonment of, or major changes to, all or part of the process.
There are certainly more events and circumstances that can lead to consideration of a control system overhaul or replacement. Numerous paths can be charted to resolving a control system challenge of large magnitude, each with a set of costs, technical hurdles, logistics, and time constraints that must be considered. Successful project completion will likely require the services of outside vendors and contractors with expertise in areas of concern.

ABB is a global leader in distributed control system design, hardware, and software. Their expertise can be brought to bear on:
  • New projects or installations
  • Support for existing ABB installations
  • Migration from other vendors
  • Industry specific requirements
  • Extending useful life of heritage systems
Having global and local expertise on board will help your DCS project proceed expeditiously from concept and planning through implementation. Reach out to a DCS expert with your concerns and challenges, then combine your process knowledge with their product application expertise to build an effective solution.

Thursday, December 15, 2016

Versatile Thermal Dispersion Switches For Level, Temperature, Liquid Interface, and Flow Applications

flow level interface temperature switch for fluid process control
Sanitary version of  FLT93 FlexSwitch
Courtesy Fluid Components International
Thermal dispersion, as a method of process measurement, relies upon precise temperature measurement and, in some cases, the ability to measure heat input. The principal is fairly simple, based upon the relationship between two temperature measurement points in the subject fluid. One is heated by the control system in a known manner, the other is not. Whether measuring fluid flow, or functioning as a liquid level or interface switch, the relationship between the two temperature measurements can provide the needed information reliably, accurately, and without any moving parts in the measurement system.

Fluid Components International utilizes these physical principals in the operation of their FlexSwitch line of thermal dispersion measuring instruments. By combining modular components in various ways, the company offers switches suitable for applications across a wide range of industries.

  • Flow
  • Level
  • Flow and temperature
  • Level and temperature

Features throughout the product line include:

  • Dual trip points and relays
  • SIL 2 rated, ultra reliable
  • 3 year warranty
  • Broad agency approvals
  • Suitable for full range of pipe sizes
  • Apply in fluids to 850 °F (454 °C)
  • No moving parts to foul, clog or maintain
  • All welded elements
  • Easy to install and set-up
  • Highly sensitive and accurate
  • Threaded, flanged, packing gland installation
  • Integral or remote mounted electronics
  • Choice of enclosures
  • Field selectable AC or DC power
More information about the FlexSwitch line of thermal dispersion based switches is provided in the document below. For best results, share your project requirements and challenges with a product application specialist. Combine your process knowledge with their product application experience and develop effective solutions.



Wednesday, October 26, 2016

Industrial Process Gas Chromatograph With Parallel Processing

industrial process gas chromatograph parallel processing
GC8000 Process Gas Chromatograph
Yokogawa
Gas chromatography is a common analysis tool employed in many areas of the process control industry, including oil and gas, pharmaceutical, chemical, and others. Yokogawa Corporation of America developed instrumentation to provide 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 enabled through the use of 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.


Thursday, September 15, 2016

Take Care of Your Pumps and They’ll Take Care of You

Pump protection
Figure 1. Today’s demanding industry applications
require highly efficient pump operation.
Written by Jim DeLeeSr. Member Technical Staff, Fluid Components, Inc. Reprinted with permission.

If you'd like more information after reading this article, visit www.flowtechonline.com or call
410-666-3200 in Maryland or
804-752-3450 in Virginia.


The old saying, “an ounce of prevention is worth a pound of care” may have been coined by process and plant engineers tired of repairing or replacing pumps. Pumps are often the most under serviced pieces of equipment in process automation when it comes to maintenance and prevention best practices. Unfortunately, nothing moves without the humble pump and a process becomes inefficient when they don’t operate properly or completely shutdown. Many times the pump manufacturer is seen to be the problem, when in fact the process or the surrounding equipment configuration is the cause. 

Engineers and technicians looking to optimizing their process for productive operation can start with the pump, and protecting the pump against common hazards. Pump protection improves end- product or batch quality, reduces material costs, eliminates waste and lowers maintenance costs. Taking good care of your pump delivers a positive payback. Here are some simple strategies that can be employed—starting with an analysis of process media ow rates.

Protecting Your Process—24/7

Today’s highly competitive global market finds demanding process industries such as petrochemicals (Figure 1), food/ beverage, pharmaceutical, and water/waste treatment among others, transforming their plants into 24/7 lean operations. The result is that the pumps in most plants are running near capacity to keep up with material through-put objectives and demand. One of the most common hazards to efficient pump operation is irregular material flow, which can result in three negative conditions: (1) ow turbulence, (2) low flows, or (3) dry running conditions.

A key process protection step taken by facilities and plant engineers is controlling material flow to ensure that pumps operate efficiently. This results in moving stock or product with the least possible expenditure of energy and at the same time reducing maintenance requirements and extending the life of the pump. Failing to control material flow effectively can lead to some unwanted conditions, such as cavitation, pump bearing failure, or seal failure. The first problem — cavitation — can reduce through-put, or even cause quality problems. Losing a bearing or a seal can lead to pump shut-down, possibly process line shut-down and the unfavorable conditions could get worse the further you take this type of scenario.

Monitoring for Irregular Flows

The first step in protecting your process and pump starts with analyzing the flow. You want to analyze the flow to ensure the media is owing regularly at the pressure required by the pump with a minimum headloss. Any number of process conditions can cause irregular flow, such as turbulence, temperature changes, unwanted air ingestion, etc. The problems of irregular flows and turbulence, in particular, can be especially challenging to solve because eliminating the root causes are often difficult to impossible—so you need a workaround strategy.

The chief culprit when it comes to damaged pumps is the build-up of heat from low ow or dry running conditions, which occur when liquid ow dramatically slows down or stops owing altogether through the line or the pump. When the liquid isn’t there to provide cooling, the heat can destroy a pump’s bearings or seals. If repair is even possible, it is going to be a very expensive due to repair or replacement costs and down time.

Eliminating Irregular Flows

Pumps require a stable upstream ow profile in the pipeline before liquid enters the pump for proper and efficient operation. Irregular flows often result in cavitation, a condition where cavities form in the liquid at the point of pump suction. One often cited industry pump installation guideline suggests at least 10 diameters of unobstructed pipe be placed between the point of pump suction and the first elbow or other disturbance. Obstructions and/or corrosion in a pipe can change the velocity and flow profile of the media and affect its pressure as well.

In most cases, plant real estate limitations result in the placement of elbows, valves or other equipment that are too close to a pump, and these devices can create swirl and velocity profile distortion in the pipeline (as well as pressure changes). Such disturbances can result in excess noise and cavitation, resulting in reduced bearing and/or seal life.

A good solution to ensure an optimal flow profile for efficient operation is to install an inline or elbow ow conditioner upstream from your pump. Isolating the effects of velocity profile distortions, turbulence, swirl and other ow anomalies in your pipeline will result in a repeatable, symmetric, and swirl-free velocity profile with minimal pressure loss.

To increase a pump’s life, start with a more stable operating environment. A conditioned ow stream enters the pump’s impeller in a uniform and equally distributed pattern, optimizing pump ef ciency and extending bearing life while at the same time decreasing noise and cavitation.

If there is no choice other than to deal with less than ideal piping configurations, an inline or elbow ow conditioner will eliminate all upstream straight run requirements for pumps, compressors, flow meters and other critical process equipment (Figure 2). Tab type ow conditioners, such as the Vortab® Flow Conditioner, have proved successful in these applications. Other flow conditioning technology choices, including tube bundles, honeycombs, and perforated plates, may also be considered depending upon the pressure drop limitations.

The inline or elbow ow conditioner’s profile conditioning tabs produce rapid cross-stream mixing, forcing higher velocity regions to mix with lower velocity regions. The shape of the resultant velocity profile is “ at” and repeatable regardless of the close-coupled upstream flow disturbances.

Incorporating anti-swirl mechanisms into the design of the flow conditioner eliminates the swirl condition typically seen exiting 90-degree elbows. The result is a ow stream that enters the pump in such a way that it maximizes the efficiency of its operation and reduces stress. In addition, the tapered design of the anti-swirl and profile conditioning tabs make them immune to fouling or clogging.

Pump Flow Monitoring


Avoiding the damage that is caused by a low ow or a dry running condition can be achieved by installing a point flow switch in the process loop. Dual relay flow switches will detect not only a low flow condition, but also alarm on a dry condition too. This capability allows the control system or operator to take corrective measures before the bearings of the pumps are overheated and fail.

Many types of point flow switches are available. For example, the FCI FlexSwitch® FLT Series, with its no moving parts design, offers a highly robust scheme for pump protection with its dual alarm capability (Figure 3). With Alarm 1, the switch will detect a low-flow situation anywhere between 0.01 and 3 feet per second (FPS) (.003 to.9 meters per second MPS). This low flow alarm can be regarded as a pre-warning signal for the control system or operator. Alarm 2 can be set at a no-flow condition. The system or operator can then decide to keep the pump running or to shut it down.

This dual-function flow switch indicates both flow and temperature, and/or level sensing in a single device. It can be specified in either insertion or in-line styles for large pipe or small line applications. This single switch monitors your direct variable of interest, flow, and temperature simultaneously with excellent accuracy and reliability.

When evaluating a flow switch for pump protection or any application, the first step is choosing the appropriate flow technology. There are multiple flow switch sensing technologies available, and the major ones now include:
  • Paddle
  • Piston
  • Thermal Mass
  • Pressure
  • Magnetic Reed
Each of these technologies has their advantages/ disadvantages, depending on the media and your application’s requirements. Some may be the only choice in certain media for your application. By looking at these factors, as well as your plant’s layout, environmental conditions, maintenance schedules, energy cost and ROI, you will quickly be able to narrow the field to one or two best choices.

Conclusions

Don’t fall into the trap of early pump replacement or repair by ignoring best installation and maintenance pump practices. Here are three preventive proactive steps to take to avoid early pump replacement:
  • When designing new plants or retro fitting old ones, be sure to consider pump requirements. Optimizing your process with your pumps in mind offers a wide range of benefits: higher capacity, improved quality, lower energy costs, reduced maintenance, and increased equipment (pump) life. 
  • Consider inserting a flow conditioner to eliminate turbulent ow problems. One of the most common pump problems is irregular flows caused by turbulence that frequently results when the minimum pipe straight runs required between the point of pump suction and elbows, valves or other equipment are either ignored or pushed to the limits. Inserting a flow conditioner frequently eliminates turbulent flow problems. 
  • Another key safeguard is to protect your pump from accidental low flow or dry running conditions, which can lead to bearing or seal loss requiring expense repairs. Inserting a dual alarm flow switch in your process loop not only protects the pump from damage, but will alert you to a potential problem and let you be proactive in evaluating the necessity of pump shut down.

Monday, August 22, 2016

Measuring pH and ORP eBook

Get your copy of this 72 page
eBook (courtesy of Yokogawa)

Measuring pH/ORP is very common, but taking true measurements and correct interpretation of the results is not self-evident. Certain effects can potentially cause problems if not taken into consideration.

The purpose of this book is to provide a comprehensive understanding of pH/ORP measurement and how to achieve reliable results. Basic information on the principles of measuring pH/ORP, the construction of the sensing elements and their basic use in process applications are provided.

A part of achieving accurate and reliable pH/ORP measurements requires sufficient and correct maintenance and storage conditions. Prevention of common errors during maintenance and storage, as well as consistent detection of loop failures is important. This book describes how these can be avoided and how failures can be detected.

This book is accompanied with a frequently asked question and answer section as well as an appendix that includes helpful information like a Chemical Compatibility Table and a Liquid-Application-Data-Sheet, which can be used to describe the user’s application.

Wednesday, May 25, 2016

Improve Process Control Security Using Annunciators as Watchers

ronan annunciators for security
Use annunciators for added security
Software-based systems are vulnerable to cyber attacks. Most of the industrial control networks (CAN, PROFI, Control Area, Ethernet and RS485) connect to the internet or other computer networks which are not fully protected from hackers and viruses. Present day industrial DCS/PLC control systems come with redundancy systems to eliminate shutdowns in case of DCS/PLC hardware failures. However, this does not protect your DCS/PLC system from any type of cyber attack. Without proper protection, the safety and/or operation of your plant or business are put at great risk.

The document below describes how using a stand-alone annunciator system will will work as a failsafe for DCS/PLC/SCADA systems and improve .

Monday, January 11, 2016

Mass Flow Rate and More From Multivariable Transmitter - Process Measurement and Control

Multivariable mass flow measurement transmitter
Model EJX 910A Multivariable Transmitter
Courtesy of Yokogawa
Industrial process measurement and control is charged with continually producing better, faster, and cheaper results with increasing levels of safety. For applications requiring mass flow rate measurement of fluids or tank level, a multivariable transmitter has much to offer when it comes to improving outcomes throughout your industrial process operation.

The EJX 910 series from Yokogawa provides the latest generation of digital sensing and processing to provide fast and accurate process measurement of temperature, static pressure, differential pressure, and dynamically compensated mass flow. Flow accuracy as high as +/-1.0% is achievable, along with:

±0.04% Differential Pressure Accuracy
±0.1% Static Pressure Accuracy
±0.9°F External Temperature Accuracy



Some other highlights include:

  •  Industry leading fast response time for safe and accurate process control.
  • Yokogawa's specially developed DPharp digital sensor providing simultaneous static and differential pressure measurement, digital accuracy, and no A/D conversion error.
  • LCD display can be rotated in 90 degree increments. External zero adjustment screw and range setting switch enhance field setup.
  • Improved mass flow accuracy of +/- 1% from multivariable operation in one device with dynamic compensation.
  • Signal characterizer for measuring level in irregular shaped tanks.
  • Utilizes industry recognized open communication protocols for easy integration into existing installations.

The manufacturer's white paper, describing precisely how the unit works and how it can be applied, is below. Browse the white paper for some additional detail, but consult with a product specialist to explore how to improve your process measurement and control performance. They have even more information than is provided here which, when combined with your process knowledge, is sure to generate a positive solution to any challenge.



Process Control - Five Categories of Instrument Protection


Industrial process temperature and pressure gauges
Instrument protection is a key element of process design
and equipment layout
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 headroom, can keep your process up when the unexpected occurs
.
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. Moisture also is a factor in corrosion of metal parts. Be mindful of the extra degree of protection provided by special coatings or materials that may be options for your instruments.


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 a knowledgeable 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.

Thursday, December 31, 2015

Process Control Valves: The Basics

cashco control valve
Control Valve (courtesy of Cashco)
Industrial control valve design and operation are very important to understand if you work as a process engineer, a plant maintenance person, or if you design process control loops.

Control valves are used extensively in power plants, pulp and paper mills, chemical manufacturing, petro-chemical processing, HVAC and steam distribution systems.

There are many types, manufacturers, body styles, and specialized features, but the they all share some basics operating principles. The video below explains components, operation, and fundamentals.





For more information, contact:
Flow-Tech
410-666-3200 MD
804-752-3450 VA

Wednesday, November 11, 2015

Well Grounded Knowledge for Industrial Control - Part Three of Three

Drawing symbol for electrical ground connection
Drawing Symbol for Electrical Ground Connection

This is the third part of a three part series of white papers intended to boost or reinforce your knowledge of electrical grounding for industrial process measurement and control.

Part One and Part Two were previously posted in this blog and you would be best served to read all three papers in sequence.

The series was exceptionally well written by the folks at Acromag, a world class manufacturer of industrial I/O devices.

Your questions or concerns about any aspect of your industrial process control or measurement applications are always welcome. Contact us and we will work with you to formulate a solution to a process measurement and control challenge.


Well Grounded Knowledge for Industrial Control - Part Two of Three

Electrical drawing symbol for ground connection
Drawing Symbol for Electrical Ground Connection
The use of electric power to perform work, whether using large motors or sensitive instrumentation, involves benefits and hazards. In modern society, preventing exposure of equipment and appliance users to electric shock is universally accepted as a mandate imposed upon manufacturers, installers, and operators of electrical equipment. Proper electrical grounding serves as a key element in maintaining the level of safe operation we all want to have in our facilities.

One manufacturer of industrial process control I/O devices, Acromag, has expertly written three white papers in a series providing non-technical tutorials and explanations on the subject of electrical grounding and its integral role in safety and operational integrity.
Some topics covered include:
  • The safety function of a ground connection
  • Operation of a ground fault circuit interrupter (GFCI)
  • How electrical ground can stabilize voltage and limit transients
  • Recommendations for improvement of safety and signal integrity   
  • Importance of circuit grounding
  • AC power in the United States and its use of earth ground
Part One was published previously, and it is advisable to review the three parts in sequence. The third installment follows this post. This is recommended reading for all technical levels. Industrial process measurement and control stakeholders will all benefit, whether from newly acquired knowledge or refreshed understanding of the subject.

Product and application specialists are always eager to hear about your application issues and questions. Never hesitate to contact them. Your process knowledge, combined with the product and application familiarity of a professional sales engineer, will generate good outcomes.


Well Grounded Knowledge for Industrial Control - Part One of Three

Drawing symbol for electrical ground connection
Drawing Symbol for Electrical Ground
I suspect that most control system techs have, at one time or another, come face to face with control or instrument behavior that seemed bizarre and intractable. Maybe strange behavior would come and go with no apparent explanation. Instruments or control equipment would work properly for a while, then inexplicably go south. You carefully observe illogical operation occurring without any apparent cause, and sorting it out proves to be very difficult. This is not a situation in which you want to find yourself as a service technician, operator, or vendor, particularly when process stakeholders, like your boss or customer, are observing your progress.

While many of these stories may illicit laughter when retold as history, at the time they are serious business and nobody is laughing. If you want to avoid these sweat stain inducng situations in your career, one subject on which you should be well versed is electrical grounding of your industrial process equipment and instruments. Whether a tech, vendor, or operator, solid basic knowledge about grounding principals and techniques will help you to assure the safety of personnel and equipment in your work area and keep instrumentation and controls operating as intended.

This first of three installments is shown below, expertly written by the engineers at Acromag, a world class manufacturer of I/O devices for industrial process measurement and control.  Part Two and Part Three will be published in successive posts. I recommend these white papers for all technical levels as newly acquired knowledge or refresher. This is subject matter that applies universally. Be sure to read Part Two and Part Three.

Application assistance is always available from knowledgeable sales engineers specializing in process measurement and control. The best solution to an application challenge will arise from a combination of your process mastery and the product knowledge and technical resources of your respected vendors.



Monday, October 19, 2015

Welcome to Flow-Tech's Maryland & Virginia's Process Control Blog

Virginia and Maryland Process Control
Serving Maryland and Virginia
Flow-Tech, Inc. has been specifying and applying process instrumentation and control valves in the Maryland and Virginia markets for over 40 years. Flow-Tech's outstanding growth in sales and reputation is directly a result of our consultative sales approach, delivered by our team of knowledgeable and experienced Sales Engineers.

We see this blog as an extension of that process where today's customer can learn and discover at their own time and place, narrow the selection of products and vendors, and then  arrange for me focussed presentation with a salesperson.

This blog will be populated with post we think you will find interesting and education in the area of process instrumentation and control. It will be updated frequently, so please check back often.