Happy New Year from Mead O'Brien

With 2017 coming to a close, all of us at Mead O'Brien wanted to reach out and send our best wishes to our customers, our vendors, and our friends! We hope that 2018 holds success and good fortune for all of you.

Process Temperature Sensors: Basics of Thermocouples and RTDs

Industrial Thermocouple
(Ashcroft)

Proper temperature sensor selection is key to getting useful and accurate data for maintaining control of a process. There are two main types of temperature sensors employed for industrial applications, thermocouple and resistance temperature detector (RTD). Each has its own set of features that might make it an advantageous choice for a particular application.

Thermocouples consist of a junction formed with dissimilar metal conductors. The contact point of the conductors generates a small voltage that is related to the temperature of the junction. There are a number of metals used for the conductors, with different combinations used to produce an array of temperature ranges and accuracy. A defining characteristic of thermocouples is the need to use extension wire of the same type as the junction wires, in order to assure proper function and accuracy.

Here are some generalized thermocouple characteristics.

• Various conductor combinations can provide a wide range of operable temperatures (-200°C to +2300°C).
• Sensor accuracy can deteriorate over time.
• Sensors are comparatively less expensive than RTD.
• Stability of sensor output is not as good as RTD.
• Sensor response is fast due to low mass.
• Assemblies are generally rugged and not prone to damage from vibration and moderate mechanical shock.
• Sensor tip is the measuring point.
• Reference junction is required for correct measurement.
• No external power is required.
• Matching extension wire is needed.
• Sensor design allows for small diameter assemblies. 

RTD sensors are comprised of very fine wire from a range of specialty types, coiled within a protective probe. Temperature measurement is accomplished by measuring the resistance in the coil. The resistance will correspond to a known temperature. 

Industrial RTD
(Ashcroft)

Some generalized RTD attributes:

• Sensor provides good measurement accuracy, superior to thermocouple.
• Operating temperature range (-200° to +850°C) is less than that of thermocouple.
• Sensor exhibits long term stability.
• Response to process change can be slow.
• Excitation current source is required for operation.
• Copper extension wire can be used to connect sensor to instruments.
• Sensors can exhibit a degree of self-heating error.
• Resistance coil makes assemblies less rugged than thermocouples.
• Cost is comparatively higher.

Each industrial process control application will present its own set of challenges regarding vibration, temperature range, required response time, accuracy, and more. Share your process temperature measurement requirements and challenges with a process control instrumentation specialist, combining your process knowledge with their product application expertise to develop the most effective solution.

Metso Neles T5 Series Top Entry Rotary Ball Valves

Metso's Neles® T5 series top entry rotary ball valves are designed to meet the requirements of chemical, petro-chemical and refining industries with improved process safety and efficiency of plant.

T5 series valves with famous trunnion mounted Stemball® design are suitable with wide rangeability for demanding heavy duty rotary control applications such as crude oil, hot residual oil, LPG and other hydrocarbon gases and vapors under medium and high pressures. 

Unique Stemball® design combined with anti-cavitation and low noise Q-trim technology are making the T5 series valve most suitable with wide rangeability for demanding control applications like anti surge and blow down services. The new high noise reduction Q2-trim is available for gas applications.

Metso Neles T5 Series Top Entry Rotary Ball Valves from Mead O'Brien, Inc.

Process Control Basics: The Underlying Principle Behind Coriolis Flowmeters

The Coriolis effect, a derivative of Newtonian motion mechanics, describes the force resulting from the acceleration of a mass moving to (or from) the center of rotation. As this video demonstrates, the flowing water in a loop of flexible hose that is “swung” back and forth in front of the body with both hands. Because the water is flowing toward and away from the hands, opposite forces are generated and cause the hose to twist. Coriolis flowmeters apply this principle to measure fluid flow.

For more information on any process flow application, contact Mead O'Brien by calling
(800) 892-2769 or by visiting https://www.meadobrien.com.

Pharmaceutical and Biotech Valve Communication Networks

Valve Communication Network

Pharmaceutical and biotech companies are facing increasing competition, driving their need for increased efficiency, reduced costs, and agility.

Automated valve systems that help reduce installation costs through easy set up, faster commissioning, and enhanced valve identification are being embraced in these industries. Features such as bright electronic indication, combined with optional remote wireless access systems, provide enhanced risk management and improved safety, which subsequently lowers overall cost.

Demands for higher product purity and productivity is pressuring Pharma and Biotech companies to make investments in new technologies that deliver improved quality and competitive agility. Process control systems, and specifically valve communication systems, are evolving to support these changes. The most significant changes to valve communications systems are:

Size

Valve communication modules that offer smaller, lighter and more durable form factors, and modules that conform to the needs of moveable process skids and flexible manufacturing provide operators are very popular in these industries. Also, the use of integral solenoid valves lessen the amount of tubing and cabling required for valve packages, affording smaller overall envelope sizes on skids.

Precision

Solid state continuous sensors increase reliability and provide precise position measurement compared to legacy mechanical or proximity-reed technology. These solid state sensors also allow for more sophisticated valve diagnostics, leading to reduced maintenance costs over the valve system's life cycle.

Predictive Maintenance

The information available for critical valve operating parameters allow operators to see potential problems early, thereby reducing the risk and potential expense from lost production and downtime. Remote valve function monitoring, which includes sensor temperature and cycle count, extends the life of critical valves and helps maintenance staff circumvent a problem before it causes a dangerous situation.

Improved Safety

StoneL Axiom

Wireless communications and control modules allow operators to access difficult to reach valve systems safely, securely and conveniently. Critical situations are known and dealt with immediately from safe locations, and away from potentially dangerous areas or circumstances.

Remote Access and Data Collection

Typical modern valve communication networks provide tremendous advantages over traditional valve monitoring systems, namely:

• Access devices up to 50 meters, depending on obstructions
• Monitor on or off line and set open and closed switch positions
• Monitor and set the network address
• Operate solenoid valve(s) (if network- or power supply-enabled)
• Identify model and serial number (preset from factory)
• Identify valve automation components (entered by valve supplier)
• Log maintenance information
• Monitor diagnostics (valve cycle count, electronics temperature, and more)
• Lockout of settings automatically when in operation

Solutions

StoneL Prism PI

Combining components such as StoneL’s Prism or Axiom platforms with a DeviceNet or AS-Interface protocol system to interconnect your automated valves will lower your construction costs and install faster than conventional systems. Additionally, using valve monitoring apps such as StoneL Wireless Link with standard iPads or iPhones provide further cost savings and security is assured. Maintenance schedules based on calendar days are no longer required - with access to cycle count data, you can perform valve maintenance when it is truly needed and replace parts prior to wearing out.

Example of StoneL Wireless Link on iPhone.

To discuss any valve networking application, contact Mead O'Brien by visiting https://www.meadobrien.com or by calling (800) 892-2769.

Understanding Vortex Shedding Flow Technology

Foxboro Vortex Shedding Flowmeter.
Notice the shedder bar in the flow path.

Photograph of vortices
(credit Jürgen Wagner via Wikipedia)

Vortex shedding flowmeters are a type of flowmeter available to the process industry for the consistent evaluation of flow rates. These flowmeters measure the volumetric flow rate of media such as steam flowing in pipes, gases, and low viscosity liquids, boasting both versatility and dependability. Since they have no moving parts, they are impervious to the kind of wear turbine or mechanical meters experience.

Principles of Operation
A "shedder" bar (also known as a bluff body) in the path of

Animation of vortices
(credit Cesareo de La Rosa Siqueira
via Wikipedia)

the flowing fluid produces flow disturbances called vortices. The resulting vortex trail is predictable and proportional to the fluid flow rate. This phenomena is know as the "Von Kármán vortex street" (see illustrations to the right). Sensitive electronic sensors downstream of the shedder bar measures the frequency of the vortices and produce a small electrical pulse with every vortex created. The electrical pulses also also proportional to fluid velocity and is the basis for calculating a volumetric flow rate, using the cross sectional area of the flow measuring device.

Typical Areas of Use
Vortex shedding flowmeters are used on steam, cryogenic liquids, hydrocarbons, air, feed water, and industrial gases.

Applications to Avoid
Splitting higher viscosity fluids into concordant vertices is extremely difficult due to the internal friction present, so using vortex shedding flowmeters on high viscosity media should be avoided. Also, avoid applications with low flow rates and low Reynolds Numbers, as the vortices created are unstable.

Consideration for Use
Consideration must be given to applications with low Reynolds numbers, as the generation of vortices declines at critical points of reduced velocity. Low pressure can also be a problem in this regard. Users must take Reynolds number, velocity, and density into consideration before choosing a vortex shedding flow meter. As always, it's best to discuss your application with an knowledgable support professional before specifying, purchasing, or installing this type of flowmeter.

Watch the video below for more information on vortex flow technology.

For more information on  vortex shedding flowmeters, visit https://www.meadobrien.com or call (800) 892-2769.

Inverted Submerged Bucket Steam Traps: How They Work

Cutaway diagram of the Armstrong Inverted Bucket Trap.

The inverted submerged bucket steam trap is a mechanical trap that operates on the difference in density between steam and water. Steam entering the inverted submerged bucket causes the bucket to float and close the discharge valve.

Condensate entering the trap changes the bucket to a weight that sinks and opens the trap valve to discharge the condensate. Unlike other mechanical traps, the inverted bucket also vents air and carbon dioxide continuously at steam temperature.

This simple principle of condensate removal was introduced by Armstrong International in 1911. Years of improvement in materials and manufacturing have made today’s Armstrong inverted bucket traps virtually unmatched in operating efficiency, dependability and long life.

For more information on Armstrong steam traps, visit http://www.meadobrien.com or call (800) 892-2769.

Fixed Point Gas Monitoring

Fixed Point Gas Monitors (GfG)

In industry, the assessment and control of risk factors is a crucial element of process control. Commanding risk allows not only for peace of mind regarding environments involving hazardous materials, but also ensures ' and prioritizes - the safety of those who work with said materials. Fixed point gas monitoring tracks and repeatedly evaluates the levels of potentially toxic or flammable gases in an industrial environment, typically using electrochemical, infrared, or catalytic bead sensors. A central monitoring station allows for an entire facility to operate under consistent watch, as the array of gas monitors throughout a facility form a system. Typical environments which utilize fixed point gas monitoring include CNG filling stations, fleet maintenance buildings, wastewater lift stations and treatment plants, pipelines, and refineries, among others.

Due to the variation in facilities and associated industrial purposes, the applicability and customization of fixed point monitors must be adaptable. The gases typically monitored by fixed point systems are industrial staples. Natural gas (methane) and hydrogen are inherently dangerous to work with due to both their combustible nature and flammability. Carbon monoxide, hydrogen sulfide, and chlorine are especially dangerous to those who work in and around facilities where they are used or produced, while otherwise harmless gases such as nitrogen can cause oxygen displacement leading to asphyxiation. Around-the-clock is the only way to monitor and mitigate the potential impact of such volatile substances; thanks to automation, the ability to be constantly vigilant of threats related to gases is possible.

Sensing and evaluating these types of gases is a complex process, yet one which also showcases the powers of the associated technology. International certification standards like ATEX (derived from a French regulation acronym) and SIL (the safety integrity level) allow designers of gas detectors to match their products with the necessary parameters to ensure safe working environments. For example, one manufacturer's electrochemical gas sensor operates based on a principle involving two electrodes; the first electrode senses the toxic gas, and then the second electrode receives protons generated by the sensing electrode through an ion conductor. Output current which flows to an external circuit is proportional to the concentration of gas, therefore the current generated is measurable as an indicator of gas levels. Despite the fact that these sensors are primarily used in industry, there is also the potential for domestic applicability, automotive process control, and air quality control, among other uses. The different technological and practical applications of fixed point gas monitors allow for industry professionals to safely and capably navigate working environmental hazards for personnel and process protection.

For more information on fixed point gas detection, contact Mead O'Brien by visiting http://www.meadobrien.com or calling (800) 892-2769.

The Neles B1 Series Actuator

Neles B1 Series

Metso's Neles double acting and spring return B1-Series piston type actuators are designed for use in both modulating control and on-off service. The series B1C and B1J are designed to ISO 5211/1 when Metso linkages are utilized. These actuators offer an extremely long cycle life and are well suited to operate almost any type of rotary valve.

When "stay put" is the requirement, the double acting B1C series is the choice. This series is available in several sizes with torque outputs from 40 Nm to 100 000 Nm (29.5 lbf ft to 73 756 lbf ft) for maximum supply pressure of 10 bar (145 psi).

If a failure mode is required, the spring return B1J series should be selected. This line offers a self-contained spring cartridge to provide failure in either the open or closed position. The spring return actuators are available with a mid-range spring for a 4 bar (58 psi) supply range, a lighter spring for lower supply pressure of 3 bar (44 psi) range and a stronger spring for a 5.5 bar (80 psi) range. These actuators offer torque outputs from 25 Nm to 12000 Nm (18,5 lbf ft to 8851 lbf ft) for maximum supply pressure of 8.5 bar (124 psi).

Adjustable travel stops

As with any Neles pneumatic/hydraulic actuator, adjustable travel stops are standard for both the open and closed positions. End of stroke turning angle range is 85° to 95°. Optional travel stops 0° to 90° are also available.

Wear resistant bearings

High quality bearings provide support on the upper and lower portions of the lever arm to reduce friction and expand the life of both the lever arm and the housing.
Corrosion resistance

The epoxy painted actuators have housings of rugged cast iron, with light-weight aluminum cylinders anodized for added corrosion resistance. Travel stops are stainless steel.

Self-contained spring cartridge

The springs in the B1J actuator are contained in a cartridge for added reliability and easy maintenance.

Spring to open or close capability

The standard spring return actuator on the ball valve can provide spring-to-close or spring-to-open operation sim- ply by changing the mounting position by 90°. On a high performance butterfly valve, the standard unit offers spring-to-close operation. An optional B1JA model is available for spring-to-open requirements.

High-and-low temperature construction

The standard unit can be used in temperatures up to 70 °C (158 °F). High temperature construction is available for temperatures up to 120 °C (248 °F). The standard unit can be used down to -20 °C (-4 °F). A low temperature design is available for -40° to +70 °C (-40° to 158 °F ), arctic service please refer type coding.

High cycle option

For applications where very fast and high frequency operation is required.

ATEX compatibility

Actuator construction ATEX approved.

Oversized cylinder options

The oversized cylinders (B1C 60, 75, 602, 752) are used whenever the supply pressure is limited, thus the actuators can achieve the required torques with a lower supply pressure level.

Override options

Available override devices include a manual centerpiece handle, a manual handwheel override, and a manual hydraulic override for high torque applications.

Emergency shut-down

Emergency Shut-Down (ESD) valves utilizing B1J actuators are offered to assure operation in the event of a fire or plant malfunction.

For more information about Metso Neles actuators, visit http://www.meadobrien.com or call  (800) 892-2769.

Foxboro IMT25 Flow Transmitter Quick Start Video and IOM - Everything You Need

The Foxboro® brand Model IMT25 Intelligent Magnetic Flow Transmitter uses a pulsed dc technique to excite the Models 8000A, 8300, 9100A, 9200A, 9300A, and 2800 Magnetic Flowtube coils, and convert the low level signal voltage to a digital, 4 to 20 mA, or pulse output.

FEATURES

• Digital precision, stability, and resolution ensure top measurement performance.
• Remote communication with HART communication protocol. (For FOUNDATION Fieldbus protocol, refer to PSS 1-6F5 B.)
• Remote configuration using PC-based configurator or HART Communicator.
• Local configuration using optional integral keypad, with backlighted, 2-line, LCD display.
• Scaled pulse or frequency output.
• Unidirectional or bidirectional flow.
• Analog output programmable for unidirectional, bidirectional, or multiple input range.
• Relay outputs with programmable functionality for alarms.
• Contact inputs with programmable functionality for remote operation.
• Automatic and manual zero lock.
• Online diagnostic help.
• Software configuration and totals protected in nonvolatile memory in the event of power loss.
• Compact single or dual compartment.
• Enclosure meets NEMA 4X and IEC IP66.
• Field test mode using Foxboro Model IMTSIM Magnetic Flowtube Simulator.

Foxboro IMT23 Transmitter Operation, Configuration, and Calibration from Mead O'Brien, Inc.

Solving Humidification Problems in Campus Science Lab

Background

Armstrong International’s representative affiliate, Mead O’Brien, visited Columbia College along with a local specifying engineer to determine a solution to the customer’s humidification problems in campus science labs.

The site was experiencing fluctuations in relative humidity levels due to having only one Dri-Steam GTS-600 (450lbs/hr.) installed. Because the unit was oversized for application, the swings in humidity were causing the relative humidity to exceed the spec.

Scope of Work

To meet the customer’s demand for a larger capacity, Armstrong International supplied two (2) Gas-Fired HumidiClean^TM humidifiers at 310lbs/hr. and header the units together to feed the AHU. The GFH-300s provided accuracy and turndown required to remain in spec.

Benefits

Columbia College recognized the real benefits of supplying two appropriately sized units to accomplish reliable and accurate levels of humidity in the science labs. The customer also has enjoyed the 82% efficiency rating of the GFH-300 as well as the modulated control of steam output. Because of Armstrong’s ionic bed technology, both units have required minimal cleaning and maintenance. Since installation, Columbia College has not experienced any issues with both units.

How to Use the Ashcroft 1305 Deadweight Tester

The Ashcroft 1305 deadweight tester provide a precise means for generating pressure with high accuracy that can be used as a primary calibration standard. The unit's built-in shuttle valve provides the means to control the rate of pressure increase, while precision adjustment is accomplished with an integral micro vernier displacement valve. 

This video below provides an overview of how to use the the Ashcroft 1305.

For more information on Ashcroft products, contact Mead O'Brien at (800) 892-2769 or visit http://www.meadobrien.com.

Voltage Ranging Solenoid Valve Coils are Rewriting Industry Standards

Voltage Ranging Solenoid Valves (ASCO)

New power management technology is rewriting industry standards for reliability and power consumption of solenoid valve coils. The new technology solenoid valves accepts both AC and DC voltages while improving performance. Available in 2-way, 3-way and 4-way, these solenoid valves are designed to handle most fluid control applications.

The enhanced valves are designed to be drop in replacements for existing valves. There is no change to functional attributes such as flow, pressure, ambient & fluid temperatures or physical attributes such as envelope size and face-to-face dimensions. If you're looking to just switch out a coil, enhanced coil kits are direct replacements for the old coil kits.

Here are the benefits to end customers:

Lower Power Consumption

• 1.0 watt (DC version) & 1.5 watts (AC/DC versions)
• Lowers energy cost up to 80% compared to standard solenoid valves 

RoHS 2 Compliant

• Satisfies CE Directives 2002/95/EC and 2001/65/EU (RoHS 2) for the restriction of hazardous substances 

Supervisory Current Compatible

• Suitable for systems employing supervisory currents not exceeding the following drop-out currents:
  • 20mA (12-24V DC), 15mA (24-120V AC/DC) and 7mA (100-240V AC/DC) 
• Also suitable with devices having leakage currents not exceeding the drop-out currents noted above. 

Broad Voltage Ranges Reduce Inventory

• Available in 24-120V AC/DC, 100-240V AC/DC & 12-24V DC 
• Covers hundreds of global voltage requirements
• Simplifies product selection and reduces complexity
• Lowers inventory cost by eliminating need to stock both AC & DC products
• Includes 125VDC battery (AC/DC versions) & 24VDC battery (DC version) 

DC Performance Increased Up to 500% To Match AC Ratings 

• Transition from AC to DC without sacrificing performance
• Eliminates the need for separate AC & DC output cards
• Simplifies control schemes 

Integrated Surge Suppression

• Prolongs the life of the coil by suppressing external voltage spikes
• Lowers system cost by eliminating the need for additional surge protection 

Fit For Use In Rugged and Demanding Environments

• Wide ambient temperature range for hot and cold environments
• Enclosure Types 1 through 4X for indoor and outdoor applications o Optional Class 1, Division 2 coils available for hazardous locations 

No AC Hum

• Ideal for applications requiring quiet operation

Contact Mead O'Brien at (800) 892-2769 or visit http://www.meadobrien.com for more information.

Direct Steam Injection Humidifier Replacement in Large Hospital

Direct Steam Injection Humidifier Replacement
at St. Louis Children's Hospital

The St. Louis Children’s Hospital is one of the premier children’s hospitals in the United States. It serves not just the children of St. Louis, but children and their families from across the world. The hospital provides a full range of pediatric services to the St. Louis metropolitan area and primary service region covering six states. As the pediatric teaching hospital for Washington University School of Medicine, the hospital offers nationally recognized programs for physician training and research. The hospital employees 3,000 people as well as 800 medical staff members. There are also 1,300 auxiliary members and volunteers on-site.

St. Louis Children’s Hospital was undergoing a significant renovation and determined that the original direct steam injection humidifiers that were installed over 30 years ago needed to be replaced. Within 30 years, they had only experienced minor issues due to the age and use of the humidifiers. Most issues were labeled as manifold o-ring leaks or actuator leakage (either seal kits or diaphragms).

St. Louis Children’s Hospital consulted with their local Armstrong representative, Mead O’Brien, and looked at using direct steam injection humidifiers with electric actuators versus the atmospheric steam generating humidifier. Due to the maintenance, space concerns, and, most importantly, the controllability, Mead O’Brien suggested direct steam injection humidifiers.

When replacing humidifiers during a renovation it is important to analyze the absorption distance. There are many different variables that can affect the absorption distance and, in this case, guidelines and regulations have changed over 30 years since original installation. The amount of outside air brought into the space directly affects the RH levels, and in the healthcare industry, the minimum requirement of fresh air has changed multiple times in the past 30 years. Because of this, some installations required the use of multiple manifolds to shorten the absorption distance.

During this first phase of the renovation, thirty-nine (39) new steam humidifiers were installed. Thirty-four more we supplied the following year..

In addition, the following Armstrong products were also installed:

• Six Pressure Reducing Valves 
• Three Electric Condensate Pumps 
• One Armstrong Flo-Rite
• Five VERIS Flow Meters

Because of the customer’s relationship with their local Armstrong representative, St. Louis Children’s Hospital received a quality solution that was designed to meet all of their needs and will be supported by Armstrong for many years to come.

Click this link to download the PDF version of this steam injection humidifier application note.

Hygienic Sight Flow Indicators for Pharmaceutical, Bio-pharmaceutical, and Food Processing

Hygienic Sight Flow Indicator

Jacoby-Tarbox, a division of Clark Reliance, manufactures a complete line of tubular and bulls-eye sight flow indicators manufactured specifically for pharmaceutical, bio-pharmaceutical, food, and other processing systems demanding cleanliness and maximum hygienic conditions.

Their tubular glass design allows full 360° view of the cylinder and they achieve controlled intrusion meeting ASME-BPE’s strictest requirements by employing:

• ASME BPE dimensions and Design Principles
• Precision-Bore borosilicate glass 
• Tightly tolerance EHEDG inspired O-ring capture

Watch the video below for a more detailed understanding. You can download a brochure about these hygienic sight flow indicators here.

For more information, contact Mead O'Brien at http://www.meadobrien.com or call (800) 892-2769.

Hygienic Sight Flow Indicators from Mead O'Brien, Inc.

HART Communication Protocol - Process Instrumentation

Process instrument with HART protocol (Foxboro)

The Highway Addressable Remote Transducer Protocol, also known as HART, is a communications protocol which ranks high in popularity among industry standards for process measurement and control connectivity. HART combines analog and digital technology to function as an automation protocol. A primary reason for the primacy of HART in the process control industry is the fact that it functions in tandem with the long standing and ubiquitous process industry standard 4-20 mA current loops. The 4-20 mA loops are simple in both construction and functionality, and the HART protocol couples with their technology to maintain communication between controllers and industry devices. PID controllers, SCADA systems, and programmable logic controllers all utilize HART in conjunction with 4-20 mA loops.

HART instruments have the capacity to perform in two main modes of operation: point to point, also known as analog/digital mode, and multi-drop mode. The point to point mode joins digital signals with the aforementioned 4-20 mA current loop in order to serve as signal protocols between the controller and a specific measuring instrument. The polling address of the instrument in question is designated with the number "0". A signal specified by the user is designated as the 4-20 mA signal, and then other signals are overlaid on the 4-20 mA signal. A common example is an indication of pressure being sent as a 4-20 mA signal to represent a range of pressures; temperature, another common process control variable, can also be sent digitally using the same wires. In point to point, HART’s digital instrumentation functions as a sort of digital current loop interface, allowing for use over moderate distances.

HART in multi-drop mode differs from point to point. In multi-drop mode, the analog loop current is given a fixed designation of 4 mA and multiple instruments can participate in a single signal loop. Each one of the instruments participating in the signal loop need to have their own unique address.

Since the HART protocol is a standardized process control industry technology, each specific manufacturer using HART is assigned a unique identification number. This allows for devices participating in the HART protocol to be easily identified upon first interaction with the protocol. Thanks to the open protocol nature, HART has experienced successive revisions in order to enhance the performance and capabilities of the system relating to process control. The standardization of “smart” implementation, along with the ability to function with the legacy 4-20 mA technology and consistent development, has made HART a useful and popular component of the process measurement and control industry framework.

Have a question about HART? Contact Mead O'Brien by visiting this link, or call
(800) 892-2769.

The Basics of Process Control Instrument Calibration

Calibration is an essential part of keeping process measurement instrumentation delivering reliable and actionable information. All instruments utilized in process control are dependent on variables which translate from input to output. Calibration ensures the instrument is properly detecting and processing the input so that the output accurately represents a process condition. Typically, calibration involves the technician simulating an environmental condition and applying it to the measurement instrument. An input with a known quantity is introduced to the instrument, at which point the technician observes how the instrument responds, comparing instrument output to the known input signal.

Even if instruments are designed to withstand harsh physical conditions and last for long periods of
time, routine calibration as defined by manufacturer, industry, and operator standards is necessary to periodically validate measurement performance. Information provided by measurement instruments is used for process control and decision making, so a difference between an instruments output signal and the actual process condition can impact process output or facility overall performance and safety.

In all cases, the operation of a measurement instrument should be referenced, or traceable, to a universally recognized and verified measurement standard. Maintaining the reference path between a field instrument and a recognized physical standard requires careful attention to detail and uncompromising adherence to procedure.

Instrument ranging is where a certain range of simulated input conditions are applied to an instrument and verifying that the relationship between input and output stays within a specified tolerance across the entire range of input values. Calibration and ranging differ in that calibration focuses more on whether or not the instrument is sensing the input variable accurately, whereas ranging focuses more on the instruments input and output. The difference is important to note because re-ranging and re-calibration are distinct procedures.

In order to calibrate an instrument correctly, a reference point is necessary. In some cases, the reference point can be produced by a portable instrument, allowing in-place calibration of a transmitter or sensor. In other cases, precisely manufactured or engineered standards exist that can be used for bench calibration. Documentation of each operation, verifying that proper procedure was followed and calibration values recorded, should be maintained on file for inspection.

As measurement instruments age, they are more susceptible to declination in stability. Any time maintenance is performed, calibration should be a required step since the calibration parameters are sourced from pre-set calibration data which allows for all the instruments in a system to function as a process control unit.

Typical calibration timetables vary depending on specifics related to equipment and use. Generally, calibration is performed at predetermined time intervals, with notable changes in instrument performance also being a reliable indicator for when an instrument may need a tune-up. A typical type of recalibration regarding the use of analog and smart instruments is the zero and span adjustment, where the zero and span values define the instruments specific range. Accuracy at specific input value points may also be included, if deemed significant.

The management of calibration and maintenance operations for process measurement instrumentation is a significant factor in facility and process operation. It can be performed with properly trained and equipped in-house personnel, or with the engagement of highly qualified subcontractors. Calibration operations can be a significant cost center, with benefits accruing from increases in efficiency gained through the use of better calibration instrumentation that reduces task time.

A Very Unique "No Straight Run Required" Flowmeter

VERIS Accelabar Detail

The VERIS Accelabar® is a unique flow meter that combines two differential pressure technologies to produce performance never before attainable in a single flow meter.

The VERIS Accelabar® is capable of measuring gases, liquids, and steam at previously unattainable flow rate turndowns—with no straight run requirements.

No Straight Run Required

The VERIS Accelabar® can be used in extremely limited straight run piping configurations. All necessary straight run is integral to the meter. The stabilization and linearization of the velocity profile within the throat of the nozzle eliminates the need for any upstream or downstream pipe runs.

Read the document below for more information or download the VERIS Accelabar® PDF from Mead O'Brien's website here.

VERIS Accelabar Flow Meter from Mead O'Brien, Inc.

Mead O'Brien: Experts in Valves, Valve Automation, Steam & Hot Water Systems, Process Instruments

Mead O’Brien specializes in valves & valve automation, steam & hot water products and systems, instrumentation products, skid designs, field services, surveys, assessments, and consulting.

Product Focus:

• Valves, valve automation and control
• Steam and hot water products and systems
• Instrumentation and controls

For more information, visit http://www.meadobrien.com or call  (800) 892-2769.

Please pardon our little shameless self-promotion. Thanks for watching this short video highlighting Mead O'Brien products.

Industrial Valve Actuator Basics

Electric actuator (Limitorque)

Actuators are devices which supply the force and motion to open and close valves. They can be manually, pneumatically, hydraulically, or electrically operated. In common industrial usage, the term actuator generally refers to a device which employs a non-human power source and can respond to a controlling signal. Handles and wheels, technically manual actuators, are not usually referred to as actuators. They do not provide the automation component characteristic of powered units.

The primary function of a valve actuator is to set and hold the valve position in response to a process control signal. Actuator operation is related to the valve on which it is installed, not the process regulated by the valve. Thus a general purpose actuator may be used across a broad range of applications.

Pneumatic actuator (Metso Neles)

In a control loop, the controller has an input signal parameter, registered from the process, and compares it to a desired setpoint parameter. The controller adjusts its output to eliminate the difference between the process setpoint and process measured condition. The output signal then drives some control element, in this case the actuator, so that the error between setpoint and actual conditions is reduced. The output signal from the controller serves as the input signal to the actuator, resulting in a repositioning of the valve trim to increase or decrease the fluid flow through the valve.

An actuator must provide sufficient force to open and close its companion valve. The size or power of the actuator must match the operating and torque requirements of the companion valve. After an evaluation is done for the specific application, it may be found that other things must be accommodated by the actuator, such as dynamic fluid properties of the process or the seating and unseating properties of the valve. It is important that each specific application be evaluated to develop a carefully matched valve and actuator for the process.

Hydraulic and electric actuators are readily available in multi-turn and quarter-turn configurations. Pneumatic actuators are generally one of two types applied to quarter-turn valves: scotch-yoke and rack and pinion. A third type of pneumatic actuator, the vane actuator, is also available.

For converting input power into torque, electric actuators use motors and gear boxes while pneumatic actuators use air cylinders. Depending on torque and force required by the valve, the motor horsepower, gearing, and size of pneumatic cylinder may change.

Linear pneumatic actuator (Neles)

There are almost countless valve actuator variants available in the industrial marketplace. Many are tailored for very narrow application ranges, while others are more generally applied. Special designs can offer more complex operating characteristics. Ultimately, when applying actuators to any type of device, consultation with an application specialist is recommended to help establish and attain proper performance, safety and cost goals, as well as evaluation and matching of the proper actuator to the valve operation requirements. Share your fluid process control requirements with a specialist in valve automation, combining your own process knowledge and experience with their product application expertise to develop effective solutions.

Segmented or V Ported Ball Valves

Metso Neles segment ball valve

Ball, plug and butterfly valves all belong to a class of valves commonly referred to as "quarter-turn" valves. This refers the 90 deg (angular) rotation required to go from full closed, to full open position.

In most cases standard ball, plug, or butterfly valves are not the best choice as control valves (where the process media has to be modulated or throttled). Standard ball, plug and butterfly valves usually introduce very non-linear, dynamic flow coefficients. Furthermore, they can introduce undesirable turbulence to your piping system.

As a means to linearize flow coefficients and reduce turbulent flow, the machining, or characterization, of the valve disk is done so that the machined shape allows for more optimized flow.

For ball valves in particular, machining the ball's flow port with a "V", or even by machining the ball more radically, can deliver excellent flow curves. A term for a more radically machined ball is the "segment ball" (sometimes called "segmented").  In the following video you can see how a Metso Neles segment ball valve is designed to provide excellent control.

For more information about Metso Neles valves, contact Mead O'Brien at  (800) 892-2769 or visit http://meadobrien.com.

Happy Fourth of July from Mead O'Brien

"We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness. — That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, — That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness."

THOMAS JEFFERSON, Declaration of Independence

Common Ways to Measure Steam Flow

For steam, energy is primarily contained in the latent heat and, to a lesser extent, the sensible heat of the fluid. The latent heat energy is released as the steam condenses to water. Additional sensible heat energy may be released if the condensate is further lowered in temperature. In steam measuring, the energy content of the steam is a function of the steam mass, temperature and pressure. Even after the steam releases its latent energy, the hot condensate still retains considerable heat energy, which may or may not be recovered (and used) in a constructive manner. The energy manager should become familiar with the entire steam cycle, including both the steam supply and the condensate return.

When compared to other liquid flow measuring, the measuring of steam flow presents one of the most challenging measuring scenarios. Most steam flowmeters measure a velocity or volumetric flow of the steam and, unless this is done carefully, the physical properties of steam will impair the ability to measure and define a mass flow rate accurately.

Steam is a compressible fluid; therefore, a reduction in pressure results in a reduction in density. Temperature and pressure in steam lines are dynamic. Changes in the system’s dynamics, control system operation and instrument calibration can result in considerable differences between actual pressure/temperature and a meter’s design parameters. Accurate steam flow measurement generally requires the measurement of the fluid’s temperature, pressure, and flow. This information is transmitted to an electronic device or flow computer (either internal or external to the flow meter electronics) and the flow rate is corrected (or compensated) based on actual fluid conditions.

The temperatures associated with steam flow measurement are often quite high. These temperatures can affect the accuracy and longevity of measuring electronics. Some measuring technologies use close-tolerance moving parts that can be affected by moisture or impurities in the steam. Improperly designed or installed components can result in steam system leakage and impact plant safety. The erosive nature of poor-quality steam can damage steam flow sensing elements and lead to inaccuracies and/or device failure.

The challenges of measuring steam can be simplified measuring the condensed steam, or condensate. The measuring of condensate (i.e., high-temperature hot water) is an accepted practice, often less expensive and more reliable than steam measuring. Depending on the application, inherent inaccuracies in condensate measuring stem from unaccounted for system steam losses. These losses are often difficult to find and quantify and thus affect condensate measurement accuracy.

Volumetric measuring approaches used in steam measuring can be broken down into two operating designs:

1. Differential pressure
2. Velocity measuring technologies.

DIFFERENTIAL

For steam three differential pressure flowmeters are highlighted: orifice flow meter, annubar flow meter, and spring-loaded variable area flow meter. All differential pressure flowmeters rely on the velocity-pressure relationship of flowing fluids for operation.

Orifice Flow Meter
(courtesy of Foxboro)

Differential Pressure – Orifice Flow Meter

Historically, the orifice flow meter is one of the most commonly used flowmeters to measure steam flow. The orifice flow meter for steam functions identically to that for natural gas flow. For steam measuring, orifice flow flowmeters are commonly used to monitor boiler steam production, amounts of steam delivered to a process or tenant, or in mass balance activities for efficiency calculation or trending.

Differential Pressure – Annubar Flow Meter

The annubar flow meter (a variation of the simple pitot tube) also takes advantage of the velocity-pressure relationship of flowing fluids. The device causing the change in pressure is a pipe inserted into the steam flow.

Differential Pressure – Spring-Loaded Variable Area Flow Meter

The spring-loaded variable area flow meter is a variation of the rotameter. There are alternative configurations but in general, the flow acts against a spring-mounted float or plug. The float can be shaped to give a linear relationship between differential pressure and flow rate. Another variation of the spring-loaded variable area flow meter is the direct in-line variable area flow meter, which uses a strain gage sensor on the spring rather than using a differential pressure sensor.

VELOCITY

The two main type of velocity flowmeters for steam flow, turbine and vortex shedding, both sense some flow characteristic directly proportional to the fluid’s velocity.

Velocity –  Turbine Flow Meter

A multi-blade impellor-like device is located in, and horizontal to, the fluid stream in a turbine flow meter. As the fluid passes through the turbine blades, the impellor rotates at a speed related to the fluid’s velocity. Blade speed can be sensed by a number of techniques including magnetic pick-up, mechanical gears, and photocell. The pulses generated as a result of blade rotation are directly proportional to fluid velocity, and hence flow rate.

Vortex Flowmeter
(courtesy of Foxboro)

Velocity – Vortex-Shedding Flow Meter

A vortex-shedding flow meter senses flow disturbances around a stationary body (called a bluff body) positioned in the middle of the fluid stream. As fluid flows around the bluff body, eddies or vortices are created downstream; the frequencies of these vortices are directly proportional to the fluid velocity.

For more information on process steam management, contact Mead O'Brien by visiting http://www.meadobrien.com or call (800) 892-2769,

Limitorque QX Electronic Actuator User Instructions

Limitorque QX

The Flowserve Limitorque QX quarter-turn smart electronic valve actuator continues the legacy of the industry’s state-of-the-art, non-intrusive, multi-turn MX actuator by including an absolute encoder for tracking position without the use of troublesome batteries. The QX design provides enhanced safety and reduced downtime through improved diagnostics, built-in self-test (BIST) features and LimiGard™ fault protection.

The QX design builds on more than 10 years of experience with proven Limitorque MX technology - the first generation double-sealed electronic valve actuator from Flowserve designed to provide control, ease of use and  accuracy. The QX includes all the user-preferred features of the MX in a quarter-turn smart actuator package. It is the only non-intrusive, double-sealed quarter-turn actuator to display the Limitorque brand.

For more information on any Limitorque actuator, visit Mead O'Brien at http://www.meadobrien.com or call (800) 892-2769.

Limitorque QX Electronic Actuator User Instructions from Mead O'Brien, Inc.

Common Industrial and Commercial Process Heating Methodologies

Fuel boiler producing steam.

Process heating methodologies can be grouped into four general categories based on the type of fuel consumed:

1. Steam
2. Fuel
3. Electric
4. Hybrid systems

These technologies are based upon conduction, convection, or radiative heat transfer mechanisms - or some combination of these. In practice, lower-temperature processes tend to use conduction or convection, whereas high-temperature processes rely primarily on radiative heat transfer. Systems using each of the four energy types can be characterized as follows:

STEAM

Tube heat exchanger.

Steam-based process heating systems introduce steam to the process either directly (e.g., steam sparging) or indirectly through a heat transfer mechanism. Large quantities of latent heat from steam can be transferred efficiently at a constant temperature, useful for many process heating applications. Steam-based systems are predominantly used by industries that have a heat supply at or below about 400°F and access to low-cost fuel or byproducts for use in generating the steam. Cogeneration (simultaneous production of steam and electrical power) systems also commonly use steam-based heating systems. Examples of steam-based process heating technologies include boilers, steam spargers, steam-heated dryers, water or slurry heaters, and fluid heating systems.

FUEL

Fuel-based process heating systems generate heat by combusting solid, liquid, or gaseous fuels, then transferring the heat directly or indirectly to the material. Hot combustion gases are either placed in direct contact with the material (i.e., direct heating via convection) or routed through radiant burner tubes or panels that rely on radiant heat transfer to keep the gases separate from the material (i.e., indirect heating).  Examples of fuel-based process heating equipment include furnaces, ovens, red heaters, kilns, melters, and high-temperature generators.

ELECTRICITY

Electricity-based process heating systems also transform materials through direct and indirect processes. For example, electric current is applied directly to suitable materials to achieve direct resistance heating; alternatively, high-frequency energy can be inductively coupled to suitable materials to achieve indirect heating. Electricity-based process heating systems are used for heating, drying, curing, melting, and forming. Examples of electricity-based process heating technologies include electric arc furnace technology, infrared radiation, induction heating, radio frequency drying, laser heating, and microwave processing.

HYBRID

Hybrid process heating systems utilize a combination of process heating technologies based on different energy sources and/or heating principles to optimize energy performance and increase overall thermal efficiency. For example, a hybrid boiler system may combine a fuel-based boiler with an electric boiler to take advantage of access to lower off-peak electricity prices. In an example of a hybrid drying system, electromagnetic energy (e.g., microwave or radio frequency) may be combined with convective hot air to accelerate drying processes; selectively targeting moisture with the penetrating electromagnetic energy can improve the speed, efficiency, and product quality as compared to a drying process based solely on convection, which can be rate-limited by the thermal conductivity of the material. Optimizing the heat transfer mechanisms in hybrid systems offers a significant opportunity to reduce energy consumption, increase speed/throughput, and improve product quality.

The experts at Mead O'Brien are always available to assist you with any process heating application. Visit http://meadobrien.com or call (800) 892-2769 for more information.