Friday, December 8, 2017

Precision Turbine Flowmeters

turbine flowmeter for custody transfer
Turbine flowmeter applicable to custody transfer operation.
Image courtesy Hoffer Flow Controls
Precision turbine flow meters are specially designed to accommodate a broad range of precise fluid measurement applications. They can handle greater flow rates with lower pressure drop than other meters in their class. The turbine's high-frequency digital output is suitable for interfacing with an assortment of readout and recording equipment. Some turbine flow meters have a bi-directional design that supports reverse flow applications without a reduction in accuracy or capacity.

Turbine flowmeters can be fabricated from a variety of materials to accommodate the target media and other application considerations. Product selection should incorporate aspects of useful measuring range, corrosion resistance, and anticipated operating life for a particular application. Some beneficial product features include:
  • A low mass rotor which promotes rapid response to changes in flow.
  • Deflector cones or other structures that reduce downstream thrust on the rotor bearings to enhance performance and extend bearing life
  • Integral flow straightening tubes or other shapes that dampen the effects of upstream flow turbulence. 
  • A single moving part, the rotor.
The flowmeter housing is made of nonmagnetic materials. The rotor is made of magnetic or magnetized material. As fluid flows through the instrument, the rotor spins. The angular velocity of the rotor vanes is proportional to the fluid flow rate. Pickups mounted on the housing sense the passage of the rotor vanes, providing a pulsed signal that can be used to calculate the fluid velocity, volumetric flow rate and totalized flow.

Turbine flow meters, with their simple, durable construction and wide operating range, can be the best choice for a number of applications. As with all instrumentation, there are factors to consider when making a selection. Share your flow measurement challenges and requirements with instrumentation specialists, leveraging your own process knowledge and experience with their product application expertise to develop an effective solution.

Tuesday, December 5, 2017

Combustion Airflow Measurement

combustion airflow measuring station
Two versions of the Combustion Airflow Measurement
Station, from Air Monitor Corporation.
Image courtesy Air Monitor Corporation
A Combustion Airflow (CA) Measurement Station is a multi-point, self averaging pitot traverse station designed to provide accurate and repeatable primary, secondary and/or tertiary airflow measurement in gas, oil or coal fired power plants.

Accurate combustion airflow measurement is a key element in meeting the twofold objectives in the power industry; lowering emissions, and increasing plant performance through combustion efficiency. Precise measurement of combustion airflow and fuel rates contributes to the achievement of those objectives by providing information needed to optimize fuel to air ratios and facilitate more complete, stable combustion. Limited available straight duct runs, low airflow rates, sensor proximity to modulating control dampers, broad turndown range requirements, and high concentrations of airborne particulates inhibit the use of many other measurement methods in obtaining usable measurements.

The CA Combustion Airflow Measurement Station, from Air Monitor Corporation, is detailed in the document included below. More information is available from application specialists. Share your airflow measurement challenges of all types with experts, leveraging your own knowledge and experience with their product application expertise to develop effective solutions.

Thursday, November 9, 2017

Overview of Level Measurement Instrumentation for Chemical and Pharma Applications

stainless steel level transmitter
Nivelco manufactures a broad range of process
instruments for level measurement
Image courtesy Nivelco
Measurements of liquid or bulk solid levels within a tank or other vessel are an integral part of chemical processing. Each application presents its own set of measurement challenges, as well as practical considerations related to safety, environmental conditions, and life cycle cost.

Nivelco manufactures a broad range of instruments utilized for level measurement in industrial process applications. Technologies employed include contact and non-contact variants, along with switches and transmitters.

The brochure included below provides an overview of Nivelco products targeted for use in the chemical and pharmaceutical industries. Share your process measurement and automation challenges with application specialists, leveraging your own knowledge and experience with their product application expertise to develop an effective solution.

Friday, November 3, 2017

Distribution Quality Monitors for Water Systems

distribution on-line water quality monitoring instrumentation
Three versions of water distribution quality monitoring
instrument packages.
Image courtesy Swan Analytical Instruments
Water is an integral part of everyday life, as well as being a primary constituent of many manufactured products. The use and consumption of water brings with it a requirement for a minimum standard of quality for each application. In many instances, the standards of the local water authority or other municipal provider will suffice. When water is sourced outside of the municipal system, or further processing is used to polish the water supply to a higher standard, measurement of specific criteria is needed to assure that the water meets whatever requirements are in place for minimum production and quality standards.

Swan Analytical Instruments, globally recognized manufacturer of analytical instruments for water, integrates instrumentation for several water quality measurements into a packaged unit. Several variants are available, each with its own set of measurement targets tailored for differing application requirements. The Distribution Quality Monitors deliver a complete analytical package on a single frame, saving the customer from having to build up an entire analytical setup on their own. Every component is designed and installed to work perfectly with every other component, for a no hassle path to accomplishing necessary analytical work.

The online monitors can target chlorine, pH, conductivity, and turbidity. An electronics package provides alarms, limit switches, PID control, diagnostic alarms, and dual 4-20 mA outputs from each of three transmitters. The consolidated package embodies years of Swan experience to deliver reliable results with a minimized requirement for human attention.

For more information, share your water analysis requirements and challenges with the process measurement specialists, leveraging your own knowledge and experience with their product application expertise to develop effective solutions.

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.