Level Measurement Technology for Seal Pot Applications

Measuring and ensuring proper liquid levels in your seal pots protects expensive equipment and your brand. Whatever your application, high-quality liquid level instrumentation is crucial. For end-users that means accurate performance, advanced diagnostics, and no calibration necessary regardless of specific gravity changes. For seal pot manufacturers that means a variety of price and performance options, with worldwide safety approvals and simple, easy to stock configurations.

seal pot

Echotel® ultrasonic switches

Many seal pot users and manufacturers are looking to comply with the API Standard 682. The third edition of API 682 came out in September 2004 in order to combine with ISO 21049. Revision 3 specifically mentioned ultrasonic switches. API Standard 682 Revision 4 came out in May 2014. Revision 4 was the first mention of indicating transmitters, specifically hydrostatic, but it does open the standard to other technologies that meet purchaser approval if specified. This includes the substitution of switches in place of transmitters. However, if transmitters are selected, the recommendation is that they should be analog, two-wire type, and have 4-20 mA output. Operations seeking to adhere to API Standard 682, whether Revision 3 or Revision 4, should select liquid level measurement technology that meets these qualifications.

Level Instrumentation for Seal Pot Applications
Magnetrol® produces a series of level instruments to help protect your seal pot applications:

API 682 Revision 3 Compliant

  1. Echotel® 961 Ultrasonic Single Point Relay Switch
    Why Choose It: Offers the ultimate solution to reliable single point liquid level indication.
    Key Benefits:
  • No calibration or density configuration required
  • LED indication with optional window
  • Provides enhanced diagnostic information
  • Stainless steel enclosure available
  • Time delay available to avoid false level alarms
  • Suitable for Safety Integrity Level (SIL) 2 loops
  1. ECHOTEL 962 Ultrasonic Dual Point Relay Switch
    Why Choose It: Has two independent switches in a single instrument to achieve low level and high level indication.
    Key Benefits:
  • No calibration or density configuration required
  • Top mounted to eliminate taps and reduce costs
  • Provides enhanced diagnostic information
  • Stainless steel enclosure available
  • Time delay available to avoid false level alarms
  • Suitable for Safety Integrity Level (SIL) 2 loops

API 682 Revision 4 Compliant

  1. ECHOTEL 961 Current Shift Model
    Why Choose It: The most economical option for Revision 4.
    All the benefits of the 961 Relay Switch Model plus:
  • Two-wire device
  • Provides discrete mA outputs with continuous indication (8 mA is normal operation, 16 mA is level alarm)
  • Meets NAMUR NE43 recommendations (3.6 mA or 22 mA) for malfunction indication to provide 4-20 mA range
  1. ECHOTEL 962 Current Shift Model
    Why Choose It: Top-mounted option that eliminates taps.
    All the benefits of the 962 Relay Switch Model plus:
  • Two-wire device
  • Provides discrete mA outputs (8 mA is low level alarm, 12 mA is normal operating level, 16 mA is high level alarm)
  • Meets NAMUR NE43 recommendations (3.6 mA or 22 mA) for malfunction indication to provide 4-20 mA range
  1. Horizon® 704 Guided Wave Radar Transmitter
    Why Choose It: Provides all of the advantages of GWR and the most cost effective option.
    Key Benefits:
  • Most cost effective GWR
  • Reduce taps and costs
  • Single compartment housing
  • Continuous 4-20mA/HART output
  • NAMUR NE43 Compliant
  • Easy to stock configuration
  1. Eclipse® 706 Guided Wave Radar Transmitter
    Why Choose It: Leading edge level transmitter designed to provide measurement performance well beyond that of many of the more traditional technologies.
    Key Benefits:
  • Complete proactive diagnostics with automated waveform capture
  • Available with DTMs and allows for HART or Foundation Fieldbus installations
  • Accurately measures from the bottom to the top of the probe for small ranges without a dead zone or transition zone
  • Superior signal-to-noise ratio

More Information
For more information about level measurement technology for seal pot applications, and other technologies that can protect your applications, visit echotel.magnetrol.com.

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Level Measurement Solutions for Coal Storage and Containment

Although some power plants are now fueled by renewable energy sources, coal-fired power plants are still a staple of the power industry. One important aspect of managing a coal-fired plant is ensuring safe coal storage.

Magnetrol® has produced an applications brochure for the power industry, detailing measurement challenges and solutions for each step of the power generation process. This blog post is part of an occasional series exploring each application in detail.

coal storage

A coal storage facility.

Level Measurement Challenges and Considerations

Raw coal is delivered to a coal yard in aggregate pieces of approximately 6″ that are later reduced in size by a crusher to approximately 1.5″. Enclosed storage of crushed coal is common in frigid climates and where containment of coal dust is controlled to protect populated areas. Hoppers and silos store active and reserve crushed coal prior to its pulverization into the powdered form suitable for boiler combustion.

Some severe power plant accidents in years past have been traced to coal dust ignition, and the atmospheres of contained coal storage areas are highly congested with explosive dust. For safe coal yard operation, explosion-proof, airtight level instrumentation is absolutely essential.

Level Instrumentation Solutions

MAGNETROL has produced a level instrumentation solution for safer coal storage:

  • Solitel® vibrating rod level switch, available with an extended rigid probe up to 100 inches (254 cm) or an extended flexible probe up to 65 feet (20 meters)

More Information

For more information on level measurement solutions for coal storage and other power generation applications, download the power generation brochure.

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Thermal Dispersion Technology Helps Utility Meet Federal Environmental and Health Regulations

Complying with governmental regulations while maintaining a high level of functioning is a challenge for plants throughout the process industries, and particularly in water and wastewater plants. Many water quality plants are using flow controls to help achieve critical operational goals. This case study shows how thermal dispersion mass flow meters can help your plant ensure compliance with stringent government regulations.

The Challenge

Instrumentation plays a pivotal role in meeting regulations set forth by the Environmental Protection Agency, Department of Ecology and the Department of Health. To ensure compliance with these types of regulations, the Lakehaven Utility District in Washington realized that it needed reliable flow meters for some of its most difficult applications—the air and gas flow lines serving its aeration basins and anaerobic digesters.

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A Thermatel® TA2 thermal mass flow meter in the field.

The Solution

Thermal dispersion flow meters are well accepted in the municipal industry to provide reliable flow measurement at low flows and low pressures. That’s why the District turned to the Magnetrol® Thermatel® Model TA2 for its ease of use and ability to handle these difficult applications. The THERMATEL Model TA2 mass flow transmitter measures mass flow by detecting heat dissipation from a heated surface. The sensor contains two mass balanced elements with precision matched RTDs. The reference sensor measures the process temperature (up to +400° F [+200° C]); the second RTD measures the temperature of the heated sensor. The power to the heater is varied to maintain a constant temperature difference above the reference temperature.

There is an inherent non-linear relationship between power and mass flow. The microprocessor in the TA2 compares the power against the calibration curve and converts the power requirements to the mass flow rate. Temperature is also measured to provide temperature compensation of the mass flow over the operating range of the instrument.

Because the TA2 measures air and gas directly and has excellent low flow sensitivity, it is a smart choice for challenging applications. It can provide a high degree of accuracy that ensures compliance with stringent standards such as those the District was seeking to meet.

The Results

Adding THERMATEL Model TA2 in the aeration lines maintained a minimum flow rate to prevent the diffusers from getting plugged, while also being used in conjunction with dissolved oxygen (DO) probes to provide sufficient flow to meet the oxygen demands in the basin. On the digester gas lines, the units measured the amount of methane going to fuel the boiler to generate hot water/steam for the plant, as well as the excess methane going to flare.

More Information

For more information on thermal dispersion mass flow meters and how they can help improve the efficiency and safety of your application, visit flow.magnetrol.com.

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Level Measurement Solutions for Chemical Condensers

Condensation is the heat transfer process that changes a gas or vapor to a liquid. It is employed in the reflux process to improve the efficiency of distillation. Condensation can also be employed for producing saturated liquid products, for sub-cooling, or to serve an environmental or vapor recovery function. Condensation is carried out in a variety of configurations. By properly monitoring chemical condensers, plants can ensure that distillation and other processes run as efficiently as possible.chemical condensers

Magnetrol® has produced a brochure detailing different applications throughout the ethylene industry and exploring measurement challenges and solutions for each one. This blog post is part of an occasional series exploring each application in detail.

Level Measurement Challenges and Considerations

In the distillation process, tower vapors are condensed prior to entering an accumulator. The condenser’s level can be used to control tower pressure where the liquid level set point serves as the manipulated variable (MV) for the pressure controller. Adjusting liquid level in chemical condensers changes the effective heat-transfer area.

Level Instrumentation Solutions

MAGNETROL offers a range of level instrumentation solutions for chemical condensers:

  • For point level measurement
    Series 3 float-actuated external cage level switch
  • For continuous level measurement
    Eclipse® Model 706 guided wave radar transmitter
  • For visual indication
    Atlas™ or Aurora® magnetic level indicators can be supplied with switches or transmitters 

More Information

For more information on level measurement solutions for chemical condensers and other ethylene industry applications, download the ethylene industry brochure.

ethylene brochure

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Magnetrol® Instruments With SIL Certification: Protecting Your Plant

In the process control industries, safety and reliability are paramount. Operators are searching for the peace of mind that comes from high-quality instruments. To minimize risks, the Safety Integrity Levels, or SIL, were developed as an integral part of a comprehensive safety system. SIL certification and SIL ratings guarantee a level of dependability and security that operators can trust.

Many Magnetrol® products are SIL-suitable. Below is some more information about the transmitters and switches that are SIL-Suitable or have received SIL certification:

SIL-Suitable Switches

Echotel® Model 961 Single Point Ultrasonic Level Switches
Reliable single point level measurement. Advanced self-testing continuously monitors the electronics, transducer and piezoelectric crystals. An adjustable time delay is provided for reliable measurement in turbulent processes. Rated SIL 2 FMEDA.

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Echotel® 961 and 962 ultrasonic level switches

ECHOTEL Model 962 Dual Point Ultrasonic Level Switches
Reliable dual point level measurement or pump control. A tip sensitive lower gap allows measurement to within 1⁄4″ of the vessel bottom. The flow-through upper gap allows up to a 125″ (318 cm) separation between switch points. Rated SIL 2 FMEDA.

Single-stage External Cage Float Level Switches
Field-proven switches. Self-contained units designed for external mounting on the side of a vessel, tank or bridle. Over 30 models of mechanical switches have proven their reliability and repeatability for decades in numerous applications. Rated SIL 2 FMEDA.

Single-stage Displacer Level Switches
Ideal for sumps, storage and process vessels. Models A10, A15 and External Caged Displacer Switches offer flexibility in application and are not affected by dirty liquids, coating foam, turbulence or agitation. Rated SIL 2 FMEDA.

Thermatel® TD Series Flow, Level Interface Switches
Reliable operation for flow, level, or interface detection. Offer continuous self-diagnostics. Temperature compensation provides repeatable switch operation with varying process temperature. Gas or liquid flow applications. Rated SIL 1 FMEDA.

THERMATEL TG Series Flow, Level Interface Switches
Suitable for liquid or gas flow, level, or interface detection. Provide a two-wire intrinsically safe circuit between the probe and remote DIN rail enclosure. 24 VDC input power, relay plus mA signal for flow trending/indication. Rated SIL 1 FMEDA.

SIL-Certified Transmitters

Eclipse® Model 706 Guided Wave Radar Level Transmitter
The leader in high-performance guided wave radar. This 24 VDC loop-powered transmitter utilizes a variety of coaxial, twin, and single-rod probes. Performance is not process dependent, and it is capable of measuring low dielectric liquids or solids. Rated SIL 2/3 Certified.

ECLIPSE Model 705 Guided Wave Radar Level Transmitter
Provides measurement performance well beyond that of many traditional technologies. This 24 VDC loop-powered transmitter utilizes coaxial, twin, and single-rod probes. Performance is not process dependent. Rated SIL 2/3 Certified.

E3 Modulevel® Displacer Level Transmitter
Takes displacer transmitters to the next level. Set up in as few as two steps without level movement. Microprocessor-based, HART, AMS and PACTware™ compatible, E3 offers stable, reliable 4-20 mA output in most applications. Rated SIL 2 FMEDA.

SIL-Suitable Transmitters

Jupiter® Magnetostrictive Level Transmitter
Available in single and dual float models. A loop-powered level transmitter with HART communications, PACTware™ DTM interface, LCD display and push button configuration. It may be externally mounted to a MLI or directly into a vessel. Rated SIL 2 FMEDA.

TA2 Thermal Mass Flow Meter
Provides reliable flow measurement of air and gases. Delivers excellent low flow sensitivity, high turndown and low pressure drop. Pre-calibrated and configured for the user’s application. Integral or remote electronics. Rated SIL 1 FMEDA.

More Information
To learn more about MAGNETROL products and their SIL certification, visit magnetrol.com.

sil certification

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Level Solutions for Chemical Industry Reboilers

Reboilers, or vaporizers, are heat exchangers that provide heat to the bottom of a distillation tower. They boil the bottom liquid to generate vapors which are returned to the tower to drive the distillation separation process. The reboiler may partially or completely vaporize the stream it receives from the bottom of the tower. Proper reboiler operation is crucial for distillation to be effective, and high-quality level instrumentation can ensure reboilers function correctly.

Magnetrol® has produced a brochure detailing different applications throughout the reboilerschemical industry and exploring measurement challenges and solutions for each one. This blog post is part of an occasional series exploring each application in detail.

Level Measurement Challenges and Considerations

Excess reboiler liquids (bottoms or blow-down) overflow a baffle where level is controlled by means of a level controller. If the reboiler level becomes too low, it will affect the maximum flow rate of bottoms product that can be drawn off. Inaccurate reboiler level can also degrade composition control for material balance control configurations.

Level Instrument Solutions

MAGNETROL offers a range of level instrumentation solutions for reboilers:

  • For point level measurement
    Series 3 float-activated external cage level switch or Tuffy® II float-actuated switch
  • For continuous level measurement
    Eclipse® Model 706 guided wave radar transmitter or E3 Modulevel® displacer-actuated transmitter
  • For visual indication
    Atlas™ or Aurora® magnetic level indicators can be supplied with switches or transmitters

More Information

For more information on level measurement solutions for reboilers and other chemical industry applications, download the Chemical Industry brochure.

chemical industry

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Thermal Mass Flow Meter Monitors Methane Emissions

As the EPA works towards additional methane regulations, the emphasis on compressor emissions will increase. Methane is a greenhouse gas with over 20x the global warming potential as carbon dioxide. Technologies must progress to ensure oil & gas companies meet the growing requirements of regulatory committees and monitor their methane emissions accurately.

Gas Flow Measurement Challenges

methane emissions

Magnetrol® Thermatel® TA2 with flow body (spool piece) measuring natural gas.

A leading oil & gas company required a gas flow measurement technology that could accurately measure natural gas flow rates at their compressor stations. One of the applications of interest was measuring vent gas emissions from the packing systems of compressors. This application not only required flow measurement at very low flows and low pressures, but the capability of achieving high turndown as well. Emissions can tend to increase over time as components wear, thus increasing the potential flow rates. Any instrument measuring these flow rates would need to be able to track any potential increases.

Flow Meter Solutions for Monitoring Methane Emissions

Magnetrol® produces a thermal mass flow meter, the Thermatel® Model TA2, that is based on thermal dispersion technology. The TA2 measures air and gas flow directly and has excellent low flow sensitivity, as well as high turndown ratios. Turndown is the range that the flow meter is accurate within. Most thermal mass flow meters offer 100:1 turndown, which is a drastic improvement over most technologies such as differential pressure, but certain applications demand greater. This presented an improvement opportunity for the TA2.

Since the TA2 is capable of holding multiple calibration curves, users requested added functionality of these features. To meet this need, MAGNETROL developed auto switching to fully utilize two distinct calibration curves. Auto switching will automatically alternate between a low flow curve and a high flow curve to maximize data in the customer flow range and extend the turndown. This ensures optimal performance at both low flows and the abrupt high flow (upset) condition or an increase in flow over time due to degradation of components. Plants can trust that the methane emissions levels they report are accurate because the TA2 is able to measure low and high flow rates with precision.

More Information

To learn more about how thermal mass flow meters can monitor a wide range of applications efficiently and safely, visit flow.magnetrol.com.

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Frequently Asked Questions About Ultrasonic Level Switches

Ultrasonic level switches use high-frequency sound waves that are easily transmitted across a transducer gap in the presence of a liquid media, but are attenuated when the gap is dry. The Magnetrol® ultrasonic portal, echotel.magnetrol.com, provides information about the Echotel® series of ultrasonic switches and how they can improve the safety and efficiency of many processes. Periodically, MAGNETROL product manager Tom Kemme answers questions about ultrasonic level switches in the portal’s “Ask Tom” column. This week’s blog post shares some recent Q&As.

ultrasonic level switches

Echotel® ultrasonic level switches

Question: Can ECHOTEL be used in applications that have entrained air?

Answer: Yes, ECHOTEL ultrasonic switches can be used in applications that have entrained air. All ECHOTEL gap switches feature a tip-sensitive transducer that provides superior performance over side gap transducers that are offered by other companies. Side gap transducers allow gas bubbles to adhere to the upper surface of the gap, which cause false dry gap alarms. Tip sensitive transducers allow these bubbles to pass through the gap. Applications with severe turbulence or entrained air should use the Model 961 switch, which offers a time delay adjustment. Up to 10 seconds of delay can be used to disregard entrained air and reliably detect the true liquid level.

Question: We are considering adding level alarm switches to our process to provide high-high level indication in several tanks. Instead of switches with relay outputs, we are considering the current shift output. What are the advantages of a current shift output?

Answer: Current shift electronics simply shift the current output from 8 mA when the level switch is in the normal operation, to 16 mA to indicate a level alarm. ECHOTEL Model 961 also has a user selectable fault signal of 3.6 or 22 mA. Current shift switches are 2-wire loop powered, which allows them to be offered with intrinsically safe approvals. This allows these switches to be put into hazardous area locations at a lower cost since rigid conduit is not necessary. Since current shift switches provide constant indication of either a normal (8 mA), alarm (16 mA), or a fault (3.6 or 22 mA) condition, they are sometimes referred to as a transmitter for the price of a switch.

More Information

To learn more about the advantages of ECHOTEL ultrasonic level switches, or to ask a question of your own, visit echotel.magnetrol.com.

ultrasonic level measurement 2

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Driving Down Fuel Costs With Feedwater Heater Level Control

For most power plants, 70 to 80% of their production costs are fuel expenses. Hence, any improvement in fuel efficiency can have a significant impact on a plant’s profitability. By improving final feedwater heater temperature through better feedwater heater level control, plants can reduce heat rate and realize significant cost savings. For instance, in a 500-megawatt power plant, improving heat rate by 1% could generate $500,000 in annual savings.

Heat rate is a measure of how efficiently a plant uses heat energy. The higher the heat rate, the less efficient the plant. Heat rate has a major impact on a company’s bottom line and its ability to compete in unregulated markets. The benefits of an improved heat rate go well beyond consumption and cost. A plant can see a reduction in emissions by simply reducing the amount of fuel required to generate a given amount of energy. In many cases this can be accomplished in a cost-effective manner by improving feedwater heater level control. Reducing heat rate also increases boiler longevity by eliminating overfiring. And there is significant public relations value when a plant shows itself to be taking all possible steps to minimize its impact on the environment.

Level Control Throughout the Power Cycle
Maintaining accurate, reliable level control throughout the power cycle is critical. The condenser is the beginning of the feedwater heater process, where condensed steam from feedwater heater drains and HP, IP, and LP turbines is routed through successive feedwater heaters. At the same time, extraction steam from turbines reaches the appropriate feedwater heaters and the transfer of energy takes place. Reliable, accurate level control is critical to achieving the final temperatures that this cycle requires.

feedwater heater level controlFeedwater Heater Operation
Feedwater heaters use the heat of condensation to preheat water to the correct temperature for the boiler. During this process, shell and tube heat exchangers allow feedwater to pass through the tube side and extract water from the turbine to the shell side. When controlled properly, feedwater heaters can decrease fuel costs by using extraction steam to preheat water rather than costly hot fuel. Achieving optimum water level in the feedwater heater reduces heat rate and lowers fuel costs. Making an investment in level control can help you achieve optimum heat.

Instrumentation for Feedwater Heater Level Control
The Eclipse® Model 706, a guided wave radar transmitter produced by Magnetrol®, is a smart choice for monitoring feedwater heater level control. The ECLIPSE 706 guided wave radar (GWR) transmitter can help plant operators optimize the condensing zone, deliver accurate level control, maximize energy transfer, and minimize undue wear and tear.

While older level technologies, such as differential pressure, magnetostrictive, RF capacitance, and torque tubes are often used to measure feedwater heater level, these instruments can cause issues for power plant operators. Older technologies such as these are vulnerable to process conditions, induced instrument errors, shifts in specific gravity and mechanical or electronic drift.

GWR is the truly reliable measurement solution for feedwater heater level control, because it is unaffected by process conditions, requires no calibration or gravity corrections, and has superior signal-to-noise ratio. Using a guided wave radar transmitter like the ECLIPSE Model 706 can help power plants achieve a reduced heat rate and lower fuel costs.

More Information
To learn more about feedwater heater level control, and to download a kit about managing your heat rate, visit heatrate.magnetrol.com.

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Level Measurement Solutions for Chemical Distillation Towers

Separation and purification is a crucial part of all industrial operations that deal with chemicals. Selecting a separation technology from among 20 leading varieties depends upon a chemical’s nature, the number of phases, and the capacity, speed and efficiency required. Distillation—separating substances based on differences in volatilities—is the most widely used separation and purification method. Today, approximately 40,000 distillation towers are operating in U.S. chemical plants.

Magnetrol® has produced a brochure detailing different applications throughout the distillation towerschemical industry and exploring measurement challenges and solutions for each one. This blog post is part of an occasional series exploring each application in detail.

Level Measurement Challenges and Considerations
Distillation is an energy-intensive process—in a typical chemical plant, it accounts for about 40% of the total energy consumption. Reliable level measurement is needed in order to maintain energy efficiency throughout the distillation process and lower the fuel costs needed to distill. In addition, level measurement at the bottom of a distillation tower controls the “bottoms” product rate. Poor high level control could allow liquid to back up over the stripping trays causing damage and reduced yields. Too low of a level may cause pump cavitation. In related extraction and distillation towers, interface level control provides optimal separation from associated substances.

Level Instrumentation Solutions
MAGNETROL offers a range of level instrumentation solutions for chemical extraction and distillation towers:

  • For point level measurement
    Series 3 float-actuated external cage level switch
  • For continuous level measurement
    Eclipse® Model 706 guided wave radar transmitter or E3 Modulevel® displacer-actuated transmitter
  • For visual indication
    Atlas™ or Aurora® Magnetic Level Indicators can be supplied with switches or transmitters

More Information
For more information on level measurement solutions for distillation towers and other chemical industry applications, download the Chemical Industry brochure.

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