Operating Principles, Applications, and Advantages of Coriolis Mass Flowmeters

Image courtesy of
Wikipedia

Oscillation without flow
(courtesy of Wikipedia)

The Coriolis effect acts on a medium that is accelerated through a rotating system, like a ball on a rotating disk its movement is straight, however, if the observer turns with the disk the ball is apparently deflected.

The same effect occurs with a water hose that rotates around its own axis, like a skipping rope. As soon as water flows through the host also twists. The twisting is stronger or weaker, depending on the amount of water flowing through the hose.

Oscillation with flow
(courtesy of Wikipedia)

The Coriolis effect also appears with an oscillating movement, and in a Coriolis flowmeter, two symmetric metal tubes are set vibrating by an internal driver coil. The tubes oscillate with a resonance frequency similarly to that of a tuning fork.

The oscillation is measured precisely by two pick-ups at the inlet and outlet sections. If liquids or gases flow through the tubes, a phase shift occurs the pickups measure the spatial and temporal displacement (twist). The amount of twist is proportional to the mass flow rate of fluid passing through the tubes. The greater the amount, the stronger the tubes oscillate outwards.

Finally, sensors and transmitters are used to measure the twist and create a linear flow signal as an output for monitoring and control.

Coriolis mass flowmeters are widely used throughout the process measurement and control field. Their basic operating principle, combined with modern sensor and signal processing technology,

Yokogawa ROTAMASS
Coriolis Flowmeter

provide a list of positive aspects.

• Directly measure mass flow rate based on the principle of measurement.
• Measure the mass flow rate with high accuracy of ±0.1%.
• Provide a wide usable measurement range.
• Deliver density measurement based on oscillating frequency.
• Not materially impacted by fluid viscosity or density.

Coriolis flowmeters also do not need straight pipe sections upstream or downstream of the flowmeter. They also have the ability to measure non-conductive fluids.

The video below is produced by Yokogawa, a world class manufacturer of industrial process measurement and control instrumentation. It provides a clear and insightful illustration of the Coriolis principle and how it is used to provide accurate mass flow measurement.

Use High Visibility Dials on Pressure and Temperature Instruments

Reotemp HiVis Dials

Here is a real-life case study of how high visibility (HiVis) dials on pressure and temperature gauges improved safety and efficiency at a US power plant.

Like most industrial plants, there were a number of recessed areas where light was blocked by equipment, piping, etc. This created low-light areas and shadows that can make it difficult to see and read instrumentation like pressure gauges. In some cases, gauges were mounted high above head and were difficult to read from the floor.

When gauges are hard to locate and read, it makes the operator’s job more difficult and increases the likelihood of human error.

Without Hi-Vis Dial

• Gauges can be misread.
• Gauges can be misidentified.
• Gauges can be overlooked. 

With Hi-Vis Dial

• Gauges are more easily seen in low light environments.
• Gauges are easier to read at a distance.
• Gauges are more noticeable and easier to locate.
• Safety is increased. Hi-Vis = Hi-Safety.

After walking around the plant and evaluating the gauge’s visibility in a few low-light areas, the plant supervisor was confident the Hi-Vis dials would increase gauge visibility and plant safety. The decision was made to transition every gauge in the facility to the Hi-Vis dials.

In the following months, over 100 Hi-Vis dial pressure gauges were installed. The operators were now able to easily locate and read all of the pressure gauges. The plant’s supervisor had successfully increased the safety in his facility and has continued to use the Hi-Vis as the standard for all new pressure gauge applications. Plans are underway to replace all existing gauges in the Cooling Towers and Chiller Plant

For more information, contact:
Power Specialties, Inc.
9118 E. 72nd Terrace
Raytown, MO 64133
Toll Free: (800) 432-6550
Phone: (816) 353-6550
Fax: (816) 353-1740

Magnetic Level Gauges for Visual Tank Level Monitoring and Control

Magnetic Level Gauges
(courtesy of Hawk Measurement)

Magnetic Level Gauges (MLG) are widely applied in the monitoring and process control of liquid level and interface for many industries; such as petroleum, chemical, power, paper, metallurgy, water treatment etc. They are suitable for real time, precise, safe and reliable continuous measurement of process level.

Based on the principle of magnetic coupling and buoyancy, the magnetic level gauge provides real-time measurement for level and interface. The Magnetic Level Gauge (MLG) is connected to a process vessel. Within the chamber is a float containing a 360° magnetic ring. Outside of the chamber is an indicator equipped with a vacuum glass tube, which contains a bi-colored two-face magnetic bargraph. In response to the level movement, the float moves accordingly, forcing the magnetic bargraph to turn and change color. True liquid level is indicated or “read” from the corresponding point on the measuring scale. The indicator uses hermetical sealed glass tube technology to clearly indicate the level, which eliminates the common problems of glass gauges, such as vapor, condensation and liquid leakage etc.

Typical Applications:

• Boiler: Steam drum liquid level
• Power generation: Auxiliary machinery liquid level (HP reheater, LP reheater, deaerator, condenser and heating network heater etc), chemical water
• Coal Chemical: Methanol, dimethyl ether, synthesis ammonia/urea, MTO, CTL, SNG
• Silicon industry: Organic silicon, polycrystalline silicon
• Petroleum and petrochemical: Oil and gas, ethylene, trimerization and etc.
• Fine Chemicals: Methane oxide, epoxy ethane, aniline, PTMEG, BDO, carbon fiber, POM,acetic acid, styrene, rubber, crude benzol refining
• Others: Metallurgy, paper-making, water treatment, biological, pharmaceutical, food and beverage etc.

Magnetic Level Gauges have a simple modular design, composed a main chamber, a float and an

Mag level gauge construction

indicator.

Typical main chamber features:

• ANSI standard design or special manufacture
• Multi-forms installation and process connection
• Chamber Material: 304/304LSS, 316/316LSS, 317SS, 321SS, 347SS, Ti2, Hastelloy C-276, Zr-702, Nickel-6, 304+PTFE, CPVC and PP.

Typical float features:

The float is the key component of the level gauge, which magnetically couples to the outside indicator, liquid level switch and transmitter.

• Hermetically sealed incompressible
• 360° magnetic ring
• 316LSS, Hastelloy C-276, Zr-702, Nickel 6, Ti2, 304SS+PFA, grade V aviation titanium alloy and other materials
• Special structure and precision manufacturing technology of pulse TIG and laser weld
• Range of temperature: -320 to 1000°F (-196 to 538°C)
• Range of pressure: vacuum to 600 psig (vacuum to 42MPa)
• Suitable for harsh working conditions, such as HTHP, cryogenics and strong corrosion.

Relationship of float, chamber and indicator.

Typical indicator features:

• 316SS or aluminium ruler
• Hermetically sealed glass tube with no contact with medium
• Magnetic bargraph is made from special high and low temperature - resistant materials
• Magnetic bargraph is mechanically interlocked to avoid random rotating
• Selectable engineering units
• Immune to oxidation, corrosion and the effects of dust

Careful Control of Moisture in Wheat Flour Process Prevents a Sticky Mess

Infrared moisture analyzer
(courtesy of Chino America)

Wheat flour production requires very accurate moisture control because wheat flour powder is easy to be converted into a sticky, doughy mess with excess moisture. In order to prevent excess moisture from “gumming” up the works, the use of infra-red light moisture analyzers are deployed.

IR moisture analyzers shine light onto the product as it passes along via conveyor belt. The instrument measures the light being reflected back by the sample. Since the moisture in the product will absorb some of the IR light, fewer of those particular wavelengths are reflected back to the measurement sensor in the instrument. By determining the amount of light absorbed you can calculate the amount of moisture in the product.

Moisture detection diagram for wheat flour process
(courtesy of Chino America)

The analyzers used in the wheat flour application measure from 5 to 15% moisture (with a ±0.2% accuracy) in the flour during the final processing before its packed into bags. By using this IR analyzer, maintaining very consistent quality and avoiding too much moisture in the product is possible.

Chino Infrared Moisture Analyzer

Additionally, production costs were lowered because of more efficient control of its drying process. To prevent over-drying, a cascade control scheme was adopted, where the signals from moisture gauge combined with temperature measurement are used to control temperature of the drier.

For more information on Infrared moisture analyzers, contact:

Power Specialties, Inc.
9118 E. 72nd Terrace
Raytown, MO 64133
Toll Free: (800) 432-6550
Phone: (816) 353-6550
Fax: (816) 353-1740

Pneumatic Combustion Air and Flue Gas Damper Drives Provide Greater Efficiency

Stack Damper at Refinery
(courtesy of Rotork Type K)

Combustion air and flue gas damper drives fill a critical role requiring safety, accuracy and reliability above all else. Pneumatic type, rotary damper drives improve the efficiency and reliability of large and small boilers, furnaces and process heaters by maximizing combustion efficiency, minimizing emissions and reducing installation costs.

Rotary pneumatic drives deliver quality and power, but most importantly the provide precise control and speed to improve the BTU/Fuel ratio and increase the MW/Fuel ratio. This "better burn" results in reduced emissions, lower fuel consumption and improved boiler draft control. Specifically, these drives provide:

• High speed continuous modulation of ID/FD fan and inlet guide vanes
• Improved modulation and control of secondary air dampers
• Improved automation and burner management
• Quick response to plant demand
• Improved reliability in high temperature environments
• Precise damper and burner positioning
• Simple commissioning and diagnostics
• Low running costs, virtually maintenance free
• Pneumatic, analog and bus network communications

Pedestal mount damper drive
(courtesy of Rotork Type K)

The heart of the rotary pneumatic drive is the high performance rotary vane actuator. The totally enclosed design eliminates internal gears, levers and crank arms where hysteresis is created, leaving an output that has no “lost motion”, “slop” or “backlash”.  The result is the most accurate and repeatable pneumatic damper drive available to the industry.

Finally, these damper drives are designed as a "drop-in-place" solution that precisely fits into the application with no field modifications.  The concept focusses on providing the end-user with a high-performance drive that can be installed without any field engineering or modification using basic hand tools in a few hours. Existing connecting rods and linkages are reused without modification. Retrofit drives fit directly on the existing mounting pad using existing hardware.

Before retrofit

After retrofit

For more information about pneumatic combustion air and flue gas damper drives, contact:

Power Specialties, Inc.
9118 E. 72nd Terrace
Raytown, MO 64133
Toll Free: (800) 432-6550
Phone: (816) 353-6550
Fax: (816) 353-1740

www.powerspecialties.com

Thermal Mass Flow Meters

Various styles of thermal mass flow meters
(courtesy of Fox Thermal Instruments)

Thermal mass flow meters measure flow by introducing heat into a flow stream and measuring the dissipation of heat between temperature measurement points. They are very popular because they provide a fairly unrestricted flow path, have no moving parts, are accurate over a wide range of flow rates, work well on large or small pipes, don’t require temperature or pressure compensation, and actually calculate mass flow rather than volume. In most cases, thermal flow meters are used to measure and monitor flowing gases, but in some cases they are used to measure the flow of liquids.

Fox Thermal Instruments, located in Marina, CA, manufacturers some of the most innovative and reliable thermal mass flow meters today. Their products are used in a wide variety of industrial gas flow and emissions monitoring applications.

Fox provides three basic models:

Model FT1:
Winner of the 2015 Flow Control Innovation Awards, is the newest Thermal Gas Mass Flow Meter offered from Fox Thermal Instruments.  The Model FT1 was nominated for this award because of its innovative design elements such as the DDC-Sensor™ technology platform that allows it to operate using the Gas-SelectX® gas menu selection tool.

Model FT2A:
The Model FT2A continues to accurately measure gas flow rate in standard units without the need for temperature and pressure compensation. Some additional features available on the FT2A include a standard display, a standard USB port to connect to a PC, and the option of BACnet MS/TP communication protocol.

Model FT3:
The Model FT3 measures gas flow rate in standard units without the need for temperature and pressure compensation.  Calibration Validation, using the CAL-V™ and Zero CAL-CHECK® features, is an in-situ calibration routine that validates the flow meter’s accuracy by testing the functionality of the sensor and it associated signal processing circuitry.

This following brief video quickly presents the specifications and features for each model.

For more information, contact:

Power Specialties, Inc.

9118 E. 72nd Terrace

Raytown, MO 64133

Toll Free: (800) 432-6550

Phone: (816) 353-6550

Fax: (816) 353-1740

www.powerspecialties.com

Unique DP Cell Design Allows for Simultaneous Differential Pressure and Static Pressure Sensing

Design eliminates additional
hardware requirements.

DPharp digital sensor has the unique ability to simultaneously measure static pressure and differential pressure. Additionally capsule and housing temperatures are also measured. Multi-sensing platform enables real-time dynamic compensation for unmatched precision and forms the basis for implementation of advanced diagnostics. These information are available through various digital communication protocols; providing additional insight into your process. Multi-sensing functionality with guaranteed accuracy of static pressure signal allows the process to operate with fewer devices delivering reduced lifecycle costs

For more information please read the document below:

Yokogawa DPharp Differential Pressure and Pressure Transmitters from Power Specialties, Inc.