Tuesday, October 10, 2017

Applying Turbine Flow Meters With Clean Liquids and Gases

turbine flowmeter flow meter with flange connections
Turbine flow meter
Image courtesy Hoffer Flow Controls
A turbine flow meter provides a volumetric measurement of liquid or gas flow through the use of a vaned rotor (turbine) inserted in the fluid flow path. Fluid movement causes the turbine to rotate at an angular velocity proportional to the flow rate. A pickup senses the passage of the rotor vanes, producing a sine wave electrical signal output which is detected by the unit electronics. The frequency of the signal relates directly to the turbine rotation and fluid flow rate.

Generally, a turbine flow meter is applied to measure unidirectional flow. Some turbine flow meters, through the use of two pickups, have the capability to measure flow in both directions.

There are a number of considerations when selecting a turbine flow meter:
  • Material of construction: Numerous material options are available for the housing and internal parts. Proper selection considers media characteristics and cost.
  • Bearing selection: The combination of bearing type and material will likely be selected by the device manufacturer, based upon a comprehensive application information set.
  • Pickup selection: Several pickup options may be available, with the manufacturer making a recommendation that best suits the application parameters.
Here are a few other things to consider about applying turbine flow meters:

  • Turbine flow meters are precision instruments and will not tolerate debris well. An installation should include a strainer configured to trap debris that may damage the instrument or hinder its operation.
  • For longevity, it is advisable to size the flow meter to avoid extended operation near the upper end of its rotational range. Excessive rotational speeds can accelerate wear on bearings.
  • Lower rotor mass will provide more rapid response to changes in flow, allowing use of the device in applications with flow pulsations.
  • Maintain sufficient downstream pressure to prevent flashing or cavitation. This condition will cause the instrument to produce readings higher than the actual flow rate.
  • Sufficient straight pipe length should be installed at the inlet and outlet of the flow meter to provide flow conditioning necessary for accurate readings. In some cases, a flow staightener may be needed on the upstream side.
  • The output signal from the pickup may need amplification or other signal conditioning. Electrically noisy environments or long cable lengths may require special treatment.

Careful consideration of what is necessary for proper operation will pay off with reliable and accurate performance, low maintenance, and a long service life. Share your flow measurement challenges with product application experts, combining your process knowledge with their product application expertise to develop effective solutions.



Wednesday, October 4, 2017

Load Cell Application in Process Measurement

load cell industrial weighing module
Load cell incorporated into an industrial weighing module
Image courtesy of BLH Nobel
In industrial application of process measurement and control, principles of the physical sciences are combined with technology and engineering to create devices essential to modern high speed, high accuracy system operation. Years of research, development, and the forward march of humanity’s quest for scientific knowledge and understanding yields packaged devices for process measurement that are easily applied by system designer and operators.

Load cells are the key components applied to weighing component or processed materials in modern processing. Load cells are utilized throughout many industries related to process management, or just simple weighing operations. In application, a load cell can be adapted for measurement of items from the very small to the very large.

In essence, a load cell is a measurement tool which functions as a transducer, predictably converting force into a unit of measurable electrical output. While many types of load cells are available, the most popular cell in multiple industries is a strain gauge based cell. These strain gauge cells typically function with an accuracy range between 0.03% and 0.25%. Pneumatically based load cells are ideal for situations requiring intrinsic safety and optimal hygiene and, for locations without a power grid, there are even hydraulic load cells, which function without need for a power supply. These different types of load cells follow the same principle of operation: a force acts upon the cell (typically the weight of material or an object) which is then returned as a value. Processing the value yields an indication of weight in engineering units. For strain gauge cells, the principle of deformation applies, where extremely small amounts of deformation, directly related to the stress or strain being applied to the cell, are output as an electrical signal with value proportional to the load applied to the cell. The operating principle allows for development of devices delivering accurate, precise measurements of a wide range of industrial products. Advantages of load cells include their longevity, accuracy, and adaptability to many applications, all of which contribute to their usefulness in so many industries and applications.

A common place to find a strain gauge load cell in use is off a causeway on a major highway at a truck weigh station. Through innovation, load cells have been incorporated in an efficient measuring system able to weigh trucks passing through the station, without having each stop. Aircraft can be weighed on platform scales which utilize load cells, and even trains can be weighed by taking advantage of the robust and dependable nature of the transducers. Thanks to their widespread incorporation and the sequential evolution of technology, load cells are a fantastically useful tool in process measurement and control.

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

Thursday, September 21, 2017

Magnetostrictive Liquid Level Transmitters

magnetostrictive level transmitters
Different configuration of magnetostrictive level transmitters
Image courtesy Nivelco
The numerous level control technologies, methods, and instruments all have an application range or niche where they provide a feature set and performance advantageous to other measurement means. The particular set of attributes that can push one instrument over the top in the selection process is specific to each user and application.

Magnetostrictive level transmitters provide a continuous signal indicating liquid level in a vessel. They should not be confused with what are called magnetic level gauges, an instrument that locally provides a visual indication of liquid level.

Magnetostrictive level measurement employs a precise measuring of the transit time for an electric pulse travelling on a wire extending down an enclosed tube oriented vertically in the subject media. A magnetized float on the exterior of the tube moves with the liquid surface. The float’s magnetic field interacts with a magnetic field produced along the wire to generate a return signal to the transmitter head. Processing the time from emission to return provides a measure of distance to the liquid surface.

These level transmitters offer good accuracy and ease of installation and maintenance. They are best applied with relatively clean fluids. Media that will impede the free movement of the float along the sensing tube should be avoided. Magnetostrictive level instruments are often employed alongside, or integrated with, a magnetic level gauge. The magnetic gauge provides a local indication of tank level, while the magnetostrictive transmitter delivers a level signal to monitoring and control equipment.

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


Friday, September 15, 2017

New Functional Safety Programmable Loop Display

SIL 3 capablefprogrammable functional safety loop display
SLD Functional Safety Programmable Loop Display
Image courtesy Moore Industries
Moore Industries has introduced a new Functional Safety Loop Display for industrial use. The PC programmable unit monitors and displays real time process status using one of several engineering units specified by the operator. The unit is certified by exida as a SIL 3 capable, non-interfering device for use in a safety loop.

The following excerpt from the Moore Industries blog tells more of the story...

"The SLD features an independently configured display with two rows of large characters that can be clearly read in the field and set to display any EGU, it is loop-powered by less than 2.3 Volts, and the Loop Maintenance Zener Diode Option allows removal from the loop for maintenance without interrupting your safety function. Additional features include RFI/EMI immunity, superior accuracy of ±0.012% of input scale, easy calibration, and superior reliability with up to 5 years between scheduled calibrations.

"The SLD Functional Safety Programmable Loop Display is DTM programmable. Using the Moore Industries’ optional USB communication cable, the SLD can be configured to display the signal how you want to see it using any FDT compliant host or program framework, such as free PACTware. You can even store the configuration you’ve created directly to your computer.

"The SLD is simple to setup with DTM software, allowing the SLD to be custom scaled to display information in percent or scaled directly into engineering units for indicating process measurements such as pressure, temperature, level, or flow. Use the free software to input custom and square root curves in one EGU and have the PC program convert it into a different EGU for display, or easily program span, zero, input range, display range, and filtering frequency. Select square root or linear curve from the library or quickly create a custom one for your use.

"When placed into one of our housings, the SLD has 360° flexible mounting allowing the SLD to be mounted at any angle in nearly any environment. The SLD is a non-interference device and can be taken out of the loop with the –LMD option (Loop Maintenance Diode) without affecting the integrity of the SIF loop. The SLD Functional Safety Programmable Loop Display is the perfect solution to accurately and reliably display process status in a safety loop."


More detail is provided in the datasheet included below. Share your process measurement, monitoring, and control challenges with application experts. Leverage your own knowledge and experience with their product application expertise to develop effective solutions.



Thursday, September 7, 2017

Sanitary Pressure Transmitters

Pressure transmitter Yokogawa EJA530E
The EJA-E Series pressure transmitter features
Yokogawa's DPharp sensing technology
Image courtesy Yokogawa
Sanitary processes have their own sets of governmental and organizational requirements and standards, the goal of which are the delivery of safe products that are unadulterated by contamination. To that end, there are special performance and construction features required for the processing equipment, piping, facilities, and anything that comes in contact with the product or its constituents at almost any stage of production.

Pressure transmitters are a common fixture of fluid processes, sanitary or otherwise. The connection of a pressure transmitter to a sanitary system will generally be accomplished via one of several recognized sanitary connectors. The connectors facilitate the maintenance of sanitary conditions in the process vessel or piping by blocking contaminants from entering the system, establishing a leak free seal at the connection, and not being a source of contamination to the process. Transmitters for sanitary applications must also accommodate CIP and SIP operations where certain chemicals or steam may be introduced to the system for cleaning or reducing bioburden. Installation of the instrument should allow for complete drainage from the connection back into the main process line or tank, while also providing good access to the instrument head for observation, maintenance, or validation.

Yokogawa provides their EJA-E series of pressure transmitters with a range of connection options, including those for sanitary systems. The DPharp sensing technology provides top flight performance and a wide variety of configuration options meet the needs of almost every modern process measurement requirement. Communication options include Fieldbus, Profibus, and HART. The HART option allows the use of Yokogawa's HART Field Communicator which facilitates and streamlines many regular setup and maintenance tasks.

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


Wednesday, August 23, 2017

E-Book on Combustion Efficiency From Yokogawa

high temperature industrial operation fired heater
Industrial operations employing combustion as a heat source
can benefit from available modern technology for
maximizing efficiency.
Yokogawa, globally recognized leader in a number of process control fields, has authored an e-book which provides useful insight into how operators of combustion based equipment and systems can improve efficiency and enhance safety by employing modern technology.

[All quoted passages in this article are from the Yokogawa e-book "Combustion & Fired Heater Optimization"]

The Yokogawa e-book Combustion & Fired Heater Optimization offers “an analytical approach to improving safe & efficient operations” related to the use of combustion & fired heaters in the process industries. Through presenting an overview of combustion sources, such as furnaces and fired heaters, the book states that while “fired heaters pose a series of problems from safety risks to poor energy efficiency,” those problems “represent an opportunity for improved safety, control, energy efficiency and environmental compliance.” Fired heaters “account for 37% of the U.S. manufacturing energy end use.” Tunable Diode Laser Spectrometer (TDLS) technology helps mitigate safety concerns by “measuring average gas concentrations across the high temperature radiant sections.”

The book states that the four main concerns applicable to fired heaters are asset sustainability, inefficient operations, the operator skillset, and safety and compliance. Outdated diagnostics and controls have placed unnecessary stress on operator response, making sustainability of fired heaters difficult. The emissions of fired heaters are generally higher than designed, and can be coupled with control schemes for firing rates little changed over the past 40 years. Operators, generally, lack a clear understanding of design, and even engineering principles of heat transfer are not typically included in education related to fired heaters. Confounding the situation further, “many natural draft heaters do not meet this [safety regulation] guideline with existing instrumentation and control systems.” These complications combine to form a noticeable problem Yokogawa’s technology hopes to address. The company notes how the fired heater relies on natural draft instead of forced air, meaning the heaters “typically lack the degree of automation applied to other process units in the plant.” Offering a full detail of both the control state of most fired heaters and their systems defines the process situation currently considered common in the field, while emphasizing high excess air as providing a “false sense of safety.”

The proposed TDLS system allows for the measurement of “both the upper and lower conditions in a fired heater” by “simultaneously controlling the fuel and air supply based on fast sample intervals.” Safer burner monitoring and heater efficiency results from the TDLS measurements of CO, CH4, and O2. The optimization of air flow control reduces “O2 concentration … from 6% to 2%” and increases the furnace’s thermal efficiency. Combustion control is achieved by managing fuel flow and the arch draft. The TDLS integrated system works in tandem with already established logic solver systems in the plant. The TDLS technology works as a non-contacting measurement with “full diagnostic capability” and offers “distinct advantages over single point in situ analyzers” via reduction of false readings. Specific gas measurements, fast response time, optical measurement technology, and “high and variable light obstruction” are featured components of the TDLS system highlighted to show the technology’s durability and flexibility. The longevity and reliability of the system is showcased by how the TDLS combustion management system has been operational in a major refinery since 2010. The percentage of excess O2 in sample fired heaters has decreased by 1% to 1.5%. Measurements by the TDLS system have been verified by other gas analyzers. The furnace conditions in the plant are more efficiently monitored and controlled. As a result, the furnace in the functional environment is “now near its optimum operating point, using minimum excess air.”
Yokogawa presents a process-related problem, then details the key points of the problem while unpacking the causes. The e-book introduces Yokogawa’s technology, explains the mechanics, and demonstrates how TDLS acts as a solution to the problem, supported by a tangible example. The book offers great insight for both the operational principles of fired heaters and a new technology designed to maximize efficiency in the control process.

The e-book is included below. More detail is available from product application specialists, with whom you should share your combustion and fired heater related challenges. Combining your own facilities and process knowledge and experience with their product application expertise will lead to effective solutions.


Tuesday, August 15, 2017

Tunable Diode Laser Gas Analyzers Incorporated in CEMS

cabinetized extractable tunable diode laser emissions monitoring systems
TDL analyzers cabinetized in extractive
emissions monitoring system
Image courtesy CEMTEK Environmental
Tunable diode laser absorption spectrometers provide high sensitivity and specificity in the measurement of flue gas component concentration. They are well suited for continuous emissions monitoring systems used for EPA compliant or non-compliant applications. The rugged unit design and low maintenance requirement makes the TDL technology suitable for in situ monitoring of stack emissions.

TDL spectroscopy, packaged specifically for emissions monitoring applications, offers calibration stability and fast in situ measurement. It can also be applied in a manner that avoids interference from other gases present in the sample or stack. Industrial operations, whether for direct process control or emissions compliance monitoring, have a need for accurate, reliable measurement of specific gas concentrations within a flowing medium. Tunable diode laser spectroscopy, configured for industrial use, provides a number of substantially positive attributes for these applications.

More information is provided in the document included below. Share your combustion efficiency and emissions monitoring requirements and challenges with product application specialists, combining your own knowledge and experience with their product application expertise to develop an effective solution.