Look for Robust Liquid Level Switch Design in Mechanical Buoyancy Level Controls

Mechanical buoyancy type liquid level switches were one of the first technologies used to measure fluid levels in process industries, and the devices remain a workhorse for reliable level detection in a wide range of applications, including those in the most challenging or hazardous environments.

When considering the specification of mechanical buoyancy level control instrumentation, it’s important to recognize that the design and construction of the magnetic switch mechanism – the driving component within mechanical buoyancy liquid level switches – has significant bearing on the performance characteristics of the unit.

Liquid Level Switch Mechanism

Magnetrol®, the manufacturer of the first magnetic switch designed for liquid level detection, has spent more than 80 years perfecting mechanical buoyancy switches. The following MAGNETROL switch design features demonstrate how intelligent design impacts the quality and reliability of mechanical buoyancy liquid level control solutions:

Switch Mechanism

  • Completely isolated from the process environment to prevent magnetic interference and protect integrity of switch activation.

Magnet Design

  • Magnet placed on non-wetted side of pressure boundary to prevent magnetic particles from adhering to magnet and affecting switch action.
  • Alnico magnet material ensures stability.
  • All magnets are stable to over +1000°F (+540°C).
  • Magnets “saturated” and “knocked-down” to ensure stable charge over the lifetime of the switch.

Return Spring Design

  • Return springs heat-treated to ensure consistent properties and performance over a vast temperature range.
  • All return springs used only within their elastic range to prevent damage and distortion.
  • Each return spring designed for required reset force of micro switch.

Pivot Design

  • Pivot pins machined for precision fit and smooth rotation.
  • Designed with “play” at pivots and magnet to prevent binding.
  • Adjusting screw factory-set for optimal micro switch actuation point and over-travel on both pull-in and fall-out, to ensure reliability over changing conditions.

Switch Design

  • Mercury-free, high-temperature switches for process temperatures greater than +1000°F (+540°C).
  • Silver or gold contacts that work for standard or low current applications.
  • Standard or hermetically sealed micro switches.
  • Ceramic terminal blocks provided on highest temperature applications.
  • Lead wire insulation for all application temperatures

The design integrity of MAGNETROL switch mechanisms has allowed our level controls to provide years of safe, accurate, reliable level control – with many clocking in more than a half-century of trouble-free service. For more information about MAGNETROL liquid level switch solutions, download the Mechanical Buoyancy Switch Mechanism Design Guide.

CTA Liquid Level Switch Design

Float Chamber Construction of an External Cage Level Switch an Indicator of Quality and Reliability

External cage level switches remain one of the most reliable level detection technologies available to process industries. These liquid level switches must perform in a wide range of level control applications, from basic to challenging or even hazardous. In fact, many external cage level switches must comply with the standards set out by industry authorities, such as NACE and ASME, to fulfill safety requirements pertaining to oil and gas processors, power generation plants and other sectors.

When specifying level measurement instrumentation, it’s important to recognize that its design and manufacture should fully support the needs of your critical applications. The float chamber in external cage level switch devices is built to meet specific industry ratings, making its construction an excellent indicator of the quality and reliability of the overall unit. Here are several hallmarks of design integrity of the float chamber.

Series3 External Cage Level SwitchLook for Best-In-Class Float Chamber Design and Benefits

  • Magnetic Attraction Sleeve: no magnet in process to attract ferrous particles
  • Spiral Wound Head Flange and E-Tube Gaskets: Suitable for high pressures, high temperatures and steam service
  • All Stainless Steel Trim Parts: Corrosion resistant
  • Overall Designed for High Pressure: Suitable for the toughest conditions
  • Bolting Per ANSI B16.5
  • ASME Section IX Welding: Performed by qualified welders to qualified procedures, documented and traceable
  • Weld Examination Per ASME B31.1/B31.3: Visually inspected, radiography and liquid penetrant testing as required, documented and traceable
  • Welded Float and Stem Assembly: Provides durability
  • Hydrostatic Tested at 1.5 Times Rated Pressure, Including Float: Verify pressure boundary with safety margin
  • Full Penetration Chamber and Branch Welds: High strength weld
  • Integrally Reinforced Forged Branch Outlet (Bonney-Forge style) Couplings: Allows full penetration welds
  • Low SG Floats and Displacers: Suitable for most applications
  • ASTM Listed Pressure Boundary Parts Procured with Certificate of Conformance: ASME compliance
  • Designed With Allowable Stresses Per ASME B31.1/B31.3
  • Flanges ANSI B16.5 Compliant
  • Welds and HAZ Hardness Tested: Ensures hardness levels compliant with NACE standards
  • Post Weld Heat Treatment of All Welded Carbon Steel Components: Ensures hardness levels meet NACE requirements
  • Solution Annealing of Stainless Steel Parts as Required: Ensures hardness levels meet NACE requirements

Magnetrol® manufactures an extensive offering of vertical and horizontal float and displacer switch and transmitter devices that represent the industry standards for highly reliable, highly repeatable performance. Unlike some competitive float chambers constructed “to the intent” of ASME standards, MAGNETROL chambers are designed to ASME B31.1, ASME B31.3, NACE MR0175 and MR0103 standards, meeting the toughest industry specifications. Quality engineering benchmarks have resulted in decades of maintenance-free performance from MAGNETROL liquid level switches – some of which have been in the field for as long as 50 years.

For more information about NACE and ASME specifications and float chamber construction, download the MAGNETROL Float Chamber Design Guide.

External Cage Level Switch Design

Magnetrol Elected as Regional Voka Ambassador

Zele, Belgium, September 18, 2014- Magnetrol International NV, in Zele, Belgium, was recently elected as a Regional Voka Ambassador for the Dendermonde region. The Voka Ambassadors program recognizes excellence in entrepreneurship throughout the East of Flanders.

Magnetrol employees accept the Voka Ambassador election. From left to right: Katrien Geerinckx, Johan Vanderyse, Marc Baert, Geert de Ruysscher, Maddy de Loose, Ann Robberecht, Paul D'Hoey and Steven Decrock.

Magnetrol employees accept the Voka Ambassador award. From left to right: Katrien Geerinckx, Johan Vanderyse, Marc Baert, Geert de Ruysscher, Maddy de Loose, Ann Robberecht, Paul D’Hoey and Steven Decrock.

Each year, Voka selects the regional Ambassadors based on a financial analysis and other information about the company’s business model. Voka then assigns a score to each company. The highest-scoring companies are given a chance to make a brief presentation to the Voka jury. This jury (and the audience) then elects the Ambassador based on the high scores and the strength of the presentation. Magnetrol was the elected Ambassador for the Dendermonde region and will compete against other regional Ambassadors in a further competition for the East of Flanders Ambassador on November 24.

Ultrasonic Level Transmitter Instrumentation Revives Transformer Sumps

A Magnetrol® Applications Study:

A key regional energy company owns a large coal-fired electric generating facility in the Midwest, with seven coal-fired units creating a total of 2,220 megawatts. The facility was part of the company’s massive environmental retrofit projects, an undertaking that included new selective catalytic reduction (SCR) and wet flue gas desulfurization (FGD) equipment, all of which will greatly reduce nitrogen oxide and sulfur dioxide emissions.

Ultrasonic Level Transmitter Use in Power GenerationFor the project’s transformer sump level monitoring, competitive non-contact ultrasonic level transmitter units were installed. But it wasn’t long before Magnetrol® received a call from the energy company saying that several applications with the competitor’s ultrasonic transmitters were not working consistently. Our customer informed us that they wanted replacement units that were both 120 VAC-powered and loop-powered. The Echotel® Models 335 and 355 ultrasonic level transmitter units were put to the test.

After demonstrating key features of the two ECHOTEL units, we toured the plant for a closer look at the applications. Each of our competitor’s transmitters showed loss-of-echo on their display. There was nothing particularly unusual about the application other than the presence of a slight surface agitation. The level range was less than ten feet (3m).

The ECHOTEL 335 was trialed so that the customer could gauge performance in the most demanding applications. The no-obligation trial lasted two weeks. After that period of time, the customer confirmed the ECHOTEL transmitter worked without a single loss of echo during the entire trial. The customer immediately ordered three Model 335s and two Model 355s. The units have been installed and are working fine.

The success at this large coal-fired plant has carried over to other plants owned by the energy company. Currently, dozens of ECHOTEL ultrasonic transmitters are helping this customer generate over 20,000 MW. The power industry is second only to the municipal industry for sales of ECHOTEL non-contact loop- and line-powered transmitters.

Level Measurement Techniques: Minimizing Guided Wave Radar Probe Buildup

Level measurement applications in natural gas, condensate and crude processing have some special requirements that are not always evident from instrument data sheets. The potential of solids or other materials building up on a guided wave radar probe is one example. The experience of Magnetrol® field engineers has led to the development of some simple but effective level measurement techniques to address field issues related to buildup that may not be evident in data sheets.

Level Measurement Techniques Radar Probe Buildup

A sampling of probes for the Eclipse® GWR Transmitter

Natural gas, condensate and crude processing applications can experience paraffin, asphaltenes, grit and grime. The degree to which any of these can accumulate on guided wave radar (GWR) probe buildup varies by application. Even in applications where buildup isn’t typically prevalent, it can happen over time, during cold weather periods, or when bringing units up or down due to temperature, pressure and process material fluctuations. Like distillation columns, chambers/cages/bridles may require cleaning from time to time. Below are some good practices that can minimize buildup and reduce maintenance time.

  • The use of enlarged coaxial GWR probes with more clearance reduces the chance for buildup to occur.
  • Consider using a chamber probe whenever possible. Magnetrol® offers a unique family of chamber probes, which combines the sensitivity and performance associated with coaxial probes with the viscosity immunity of a single rod.
  • Insulate the probe necks of overfill probes to reduce any cooling at the top of the probe inside the vessel, chamber, cage or bridle.
  • Chambers should be insulated even in warm weather locations. The temperature differential between a warm/hot vessel (like a separator) and uninsulated chamber/cages can be significant, resulting in paraffin deposition and/or viscosity increases.
  • Insulate chamber flanges to reduce any cooling at the top of the probe.
  • Use probes with integral flushing connection to simplify flushing/dissolving paraffin or grit. Flushing connections are an option available on all MAGNETROL coaxial GWR probes.

Eclipse Microsite


The global power generation industry is rapidly changing. Increases in power consumption, economic growth and environmental pressures are creating significant opportunities for safe and reliable plant operation.

Power Plant Efficiency Opportunities
Level control applications in power plants lend themselves to performance improvements that can enhance a plant’s overall safety, efficiency or profitability. Technologies offering more precise level indication that are not affected by process variables provide operators with the ability to better manage overall power plant performance. For example, feedwater heaters in coal-fired plants historically suffer from inefficiencies due to poor level controls, which increase heat rate, thus reducing efficiency. The illustration below indicates some of the most common level control applications in the power generation industry.

Liquid Level Applications

Power Plant Efficiency Opportunities

  1. Fuel Oil Storage: Crude oils with lower flash points represent a greater fire hazard and require safety-certified liquid level switches and transmitters.
  2. Open Atmosphere Sumps: Level control in collection and processing basins must often tolerate corrosive media, punishing weather conditions and liquids with high solids content.
  3. Condensate Storage: Accurate, reliable liquid level monitoring in the condensate storage tank ensures the proper supply of make-up water.
  4. Deaerator: Pressure fluctuations are extensive in the deaerator and result in flashing, thereby requiring level controls that can withstand varying temperatures and pressures.
  5. Condensate Drip Legs & Drains: Level instrumentation must contend with high temperatures and pressures associated with drip legs, to ensure proper functioning of the condensate collection system and prevent damage to the turbine.
  6. Steam Drums: Precise level in the steam drum is important to optimize steam/water separation and steam quality.
  7. Condenser Hotwell: Level control in the hotwell can prevent make-up water loss in the turbine cycle due to leakage, steam venting or other usage.
  8. Feedwater Heaters: Feedwater heater level is controlled to prevent damage to expensive hardware, while at the same time optimizing level control to improve efficiency (heat rate) during base load, as well as load following operations.
  9. Boiler Blowdown Tank: Good boiler blowdown practices reduce water treatment needs and operation costs, as well as the chance of catastrophic explosion.
  10. Lubrication Oil Tanks: Reliable level monitoring of lube oil reservoirs ensures proper functioning of turbines, electrical generators and other equipment with integral lubrication systems.
  11. Ammonia/Caustic/Acid Storage: Managing hazardous and non-hazardous chemical storage inventory and replenishment safely and reliably is critical to ensure availability during normal operation.
  12. Cooling Tower Basin: Proper level control in the cooling tower basin eliminates low-level damage to pumps, while preventing costly overflow conditions. Vulnerability to foam from chemical injection and modest buildup considerations are fundamental to selecting the correct level technology.

Liquid Level Control Solutions
Magnetrol offers the power generation industry one of the most complete lines of liquid level control technology solutions, as well as extensive power plant efficiency applications experience for challenging process control environments.

  • Series 75 Sealed External Cage Liquid Level Switch: Self-contained units designed for side mounting to a tank or vessel with threaded, socket weld or flanged pipe connections.
  • Series B40 High-Pressure/High-Temperature Liquid Level Switch: Specifically designed for HPHT service conditions such as boilers, available in rugged industrial or ASME B31.1 construction.
  • Tuffy® II Side-Mounted Float Switch: Compact-sized, float-actuated device for horizontal mounting in a tank or vessel through threaded or flanged pipe connections.
  • Digital E3 Modulevel® Displacer Transmitter: Advanced, intrinsically safe two-wire instrument utilized buoyancy principle to detect and convert liquid level changes into a stable output signal.
  • Displacer Type Liquid Level Switch: Offering a wide choice of alarm and control configurations, these units are well suited to simple or complex applications, including foaming or surging liquids and agitated fluids, and typically cost less than other level switch technologies.
  • Eclipse® Model 706 Guided Wave Radar Transmitter: Loop-powered, 24 VDC device utilizes diode-switching technology for outstanding signal strength, and offered with a comprehensive probe offering for a wide variety of applications.
  • Pulsar® Model RX5 Pulse Burst Radar Transmitter: The latest generation of non-contact radar transmitters offers lower power consumption, faster response time and ease of use, compared to most loop-powered radar transmitters.
  • Model R82 Pulse Burst Radar Transmitter: An economical, loop-powered, non-contact radar transmitter that brings radar performance to everyday applications.
  • Magnetic Level Indicators: AtlasTM and Aurora® magnetic level indicators offer reliable visual indicator solutions, with or without accompanying continuous level transmitters.
  • Jupiter® Magnetostrictive Transmitter: High accuracy and high linearity at a reasonable price.

Power Plant Efficiency



On a recent visit to evaluate several level transmitters on chemical storage applications at a new combined cycle power plant, I had the opportunity to work with the EPC firm, plant personnel and the chemical supplier. This provided an interesting look at the level instrumentation package for the chemical storage side of things from an engineering perspective, as well as from a daily operations point of view.

Although important measurements, the ammonia, acid and caustic storage tanks are not difficult level applications for Magnetrol® and Orion Instruments® by any stretch. However, I found that small nuances on how the applications are monitored relative to technology can have a dramatic effect on the day-to-day practicality and reliability of the type of instrument(s) used. Additionally, there are safety considerations when replenishing these chemicals, which can be addressed simultaneously with inventory monitoring by implementing a few simple, cost-effective modifications to the instrumentation package.

Chemical Storage MonitoringThese chemical storage tanks can be horizontal or vertical vessels six to ten feet in diameter/height, with the ammonia storage tank usually the largest of the three. It is not uncommon to see some type of non-contact level transmitter (Ultrasonic being the most prevalent) installed to provide level indication to the control room with a local display at the base of the tank, either in series with the 4-20 mA transmitter output or repeated from the control room. The signal to the control room tracks inventory, acts as a high alarm for overfill protection and establishes the resupply interval. The local display facilitates monitoring the offload of chemicals from the supplier’s truck.

There are a number of level technologies you could throw at these applications. My preference is Through-Air (Non-Contact) Radar or Guided Wave (Contact) Radar on the acid and caustic tanks and the latter for the ammonia storage. This doesn’t imply non-contact Ultrasonic Level transmitters or other technologies are not up to the task. Simply put, radar is indifferent to the changes in the contents of the vapor space of these vessels occurring throughout the course of the day. Oftentimes, these changes affect the Ultrasonic burst causing what I refer to as a nuisance alarm, e.g., it loses the signal intermittently or the level indication becomes erratic only to recover about the time a technician arrives on the scene. These types of issues are difficult to isolate since they are intermittent and not linked to an installation or configuration anomaly or hard fault in the instrument. If a competitively priced technology that does not require calibration and is unaffected by changing process conditions is available, I take that path. Radar meets these three criteria.

Discussions with the I&C technician and chemical supplier during the evaluation process were confined to reliability, remote indication and performance verification of the level transmitter. Both preferred an independent visual indication along the lines of a Magnetic Level Indicator (MLI) on all three tanks. From the technician’s perspective it allows for easy verification of the level transmitter’s performance and adds a layer of redundancy in case the transmitter was out of commission for whatever reason. I have a lot of confidence in our instrumentation hitting the mark right out of the gate, but I have to admit it is nice to have a second opinion on the reading following initial commissioning. Sticking these tanks is usually not an option during normal operation.

The chemical supplier’s insight focused on readability during the transfer of product from the truck to the tank. Even though he normally offloads a fixed quantity of material which the vessel should accommodate based on level indications prior to dispatch, knowing the level during the transfer process is a safety measure to prevent overfilling. His comment was that MLIs can be read easily from a distance with the occasional glance while managing other tasks, whereas, he had to be on top of an LCD-type display to monitor progress. This was particularly important when working with the ammonia storage tank.

One item worth pointing out that would simplify the commissioning of the instrument is the close proximity of the top-fill piping to the instrument mounting nozzle on the smaller acid and caustic tanks. Since non-contact technologies are ubiquitous on these applications and rely on projecting a circular or elliptical signal footprint perpendicular to the surface of the material being measured, locating the instrument nozzle as far away from the turbulence generated while top filling is the ideal. Furthermore, such close proximity allows the spray pattern created as the chemical enters the vessel to interact with the transmitted beam, which could cause a loss of signal during the fill process leaving the supplier blind as to the remaining space in the vessel. Tweaking the instrument’s configuration to overcome such obstacles is possible with time and patience. On the flipside, separating these two entry points during the design phase of the vessels would eliminate any potential problems without adding cost or extending the commissioning time.   The present nozzle/fill line configuration is another point to argue the case for an MLI or opting for Guided Wave Radar technology to eliminate any potential interference and excessive turbulence near the transmitter.

After surveying each application and visiting with the I&C department and chemical supplier, I reviewed the various options with the engineering team. Our collaboration yielded three options to improve the reliability and enhance the day-to-day functionality of the instrumentation package.

Chemical Storage Monitoring 1
The easiest modification was to replace the originally specified Ultrasonic technology with an entry level Through-Air Radar (MAGNETROL Model R82), an easy fix to improve reliability by eliminating the vapor space issues noted above without adding to the overall cost. The balance of the inventory management scheme remained the same, i.e., remote LCD indication and so forth.

Taking things a step further, we considered incorporating a Guided Wave Radar (MAGNETROL Eclipse® Model 706) in place of the non-contact technologies. The Guided Wave Radar would add cost to the instrument itself as compared to an Ultrasonic or entry level Through-Air Radar. However, if we leverage its remote transmitter option in lieu of purchasing an independent remote indicator, we can offset most of the additional cost by eliminating the secondary display and its associated costs: wiring, mounting, configuring, etc. Another benefit to this approach is more flexibility in the instrument nozzle mounting location relative to the vessel top fill piping arrangement. The Guided Wave Radar is a contact measurement whose sensing element can ignore turbulence and the chemical spray pattern previously mentioned. This added benefit not only simplifies commissioning of the instrument, but separates the measurement from the tank dynamics for improved reliability.

Lastly, we looked at including some of the “wish list” items the I&C technician and chemical supplier noted and added a visual indicator (ORION INSTRUMENTS Atlas™ or Aurora® models) for level verification, redundant and diverse measurement technologies and improved readability during normal plant operation. This approach does add cost to the instrumentation package even when taking into account the elimination of peripheral items included in a minimal installation. Aside from the ammonia storage tanks, which traditionally have the process connections in place to accommodate an externally mounted device, adding similar process connections to the acid and caustic tanks would bump up the cost of the vessel as well. In the grand scheme of things, the additional costs are minor compared to the long-term benefit, but it is something that needs to be taken into consideration for chemical storage monitoring.

Improving Solar Power Efficiency Through Level and Flow Control

Solar technologies use the sun’s energy to provide electricity, hot water, process heat and cooling. According to the U.S. Energy Information Administration, solar power presently provides less than 1% of U.S. energy needs, but this is expected to increase with the development of more efficient solar technologies. One way to enhance solar power efficiency is through the use of level and flow instrumentation to drive process improvement.


Solar Power EfficiencyDifferent solar collectors meet different energy needs. Passive solar designs capture the sun’s heat to provide space heating and light. Photovoltaic cells convert sunlight directly to electricity. Concentrating solar power systems focus sunlight with mirrors to create a high-intensity heat source, which then produces steam or mechanical power to run a generator that creates electricity. Flat-plate collectors absorb the sun’s heat directly into water or other fluids to provide hot water or space heating.


Heat Transfer Fluid Storage: Large-scale solar collectors for electric power generation require a heat transfer fluid (water, thermal oils, or ionic liquids) to absorb the sun’s heat for generating steam. Arrays of mirrored panels convert the sun’s energy into +750° F (+399° C) thermal energy that’s hot enough to create steam for turbines. The mirrors focus sunlight onto pipes of heat transfer fluid that run along the mirror’s centerline. The fluid then boils water to produce steam. Thermal fluids also help provide hot water and heat. Thermal fluids are typically stored in pressurized tanks that require level monitoring.
Recommended Continuous Level Technologies: Displacer Controller, Guided Wave Radar
Recommended Point Level Technologies: External Cage Float

Hot Water Storage: High-temperature solar water heaters provide energy-efficient hot water and heat for large industrial facilities. Thermal storage in buffer tanks provides interfaces between collector subsystems and energy-using systems. The preferred solar storage vessel is a vertical cylindrical tank designed for the maximum pressure of the supply water source, which may be as high as 150 psi.
Recommended Continuous Level Technologies: Displacer Controller, Guided Wave Radar
Recommended Point Level Technologies: External Cage Float

Pump Protection: Flow switches protect pumps from damage due to leaks or if a valve is accidentally closed downstream. A flow switch will actuate an alarm and shut down the pump when flow drops below the minimum rate.
Flow Alarm: Thermal Dispersion Flow Switch for High/Low Alarm, or Flow Switch




Level Control’s Impact on the Efficiency of Wind Turbines

Wind energy is one of the fastest-growing forms of electricity generation in the world. U.S. wind power market share is expected to reach 3.35% by 2013 and 8% by 2018. More optimistic industry experts predict that wind energy will meet 20% of the nation’s energy needs by 2030. As supply and demand for wind power grows, so will the need to increase the efficiency of wind turbines, to drive costs out of the process and deliver cost-effective renewable energy solutions.

Wind Energy Systems

Large wind conversion systems are most commonly deployed for power grid electricity generation. Smaller systems are used for water pumping. A system of blades mounted on a tower is turned by the wind to either produce mechanical work directly (via a water pump), or to employ a generator to transform mechanical work into electrical energy (wind turbines). Utility-scale wind turbines for land-based wind farms have rotor diameters ranging from 165 to 325 feet (50 to 100 meters).

Wind Turbine Level Applications

efficiency_of_wind_turbines_image2WIND TURBINE OIL RESERVOIR: As wind energy technology advances, higher demands are placed on turbine lubrication systems. Lubricant reservoirs of up to 550 gallons (2,000+ liters) serve as oil storage in centralized systems to provide lubrication for the blade bearings, blade tilt, main bearing, azimuth bearing, meshing gears, generator bearings, cylindrical gears, bevel gears, rolling and sliding bearings, worm gear units, and gear couplings. The oil reservoir is monitored using continuous or point level.
Recommended Continuous Level Technologies: Guided Wave Radar, Ultrasoni
Recommended Point Level Technologies: Float Actuated, Ultrasonic

WIND TURBINE GEARBOX: Gearbox and bearing lubrication are of particular importance due to the complexity of the gearbox and the high mechanical loads. Gearbox and bearing problems are a common cause of downtime, and loss of oil through a small leak has led to catastrophic wind turbine failures. Along with vibration, temperature, and flow sensors, a low level gearbox oil alarm is a critical safety control.
Recommended Point Level Technologies: Float Actuated, Ultrasonic

Water Pumping Level Application

WATER PUMPING STORAGE: For industrial and agricultural use, a water pumping windmill is typically placed above a well or near a river. Next to the mill a storage tank is placed to provide a buffer supply of water for when the mill is not operational. Ferro-cement and steel tanks are typically used.
Recommended Continuous Level Technologies: Guided Wave Radar, Displacer Controller, Pulse Burst Radar (Through Air), Ultrasoni
Recommended Point Level Technologies: Float Actuated, Ultrasonic

Instrumentation for Wind Energy Applications

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Improving Biopharmaceutical Process: Level Control of Caustic Soda Solution

A Magnetrol Application Study:
A biopharmaceuticals company needed an accurate and repeatable level measurement of caustic soda solution, which was used to control the biopharmaceutical process of continuous fermentation.

The application had been originally equipped with a competitor’s float system, and due to the typical “lift-off” issues that accompany those systems, it only had a measurable level of 5″ (13 cm) above the bottom of the storage tank.

Because the storage tank was only 27.5″ (70 cm) high, and any leftover solution had to be discarded, it resulted in both wasted process media and loss of yield during fermentation.

The product temperature was about +77° F (+25° C), with a pressure of 18.9 psi (1.3 bar). The container was periodically sterilized at +249.8° F (+ 121° C) for 60 min.

Since the continuous fermentation was controlled by the addition of caustic soda solution, fermentation stopped when the storage tank was almost empty and the measurable level was near 5″ (13 cm).

Since the tank was not completely emptied after completion of a cycle, every additional liter could be seen as an increase in the overall yield.

The installation position of the level measurement was fixed; and to further complicate things, a non-standard flange was required.

Until recently, the customer was unsuccessful in finding a suitable measurement technology that would offer an increase in the yield or measurement range while utilizing the required installation location.

By utilizing an Eclipse® Hygienic Model 705 guided wave radar transmitter (GWR) with a single rod X7MF probe, the customer now has a solution for accurate biopharmaceutical process control.

The GWR probe was manufactured with a special flange to meet the installation requirements. This allowed for simple replacement of the Eclipse GWR transmitter on the vessel without modifications.

In order to ensure an increase in yield, the probe was bent by the customer at approximately 50% of the rod length at 45°. This allowed measurement down to the lowest point of the tank, which led to a significant increase in yield.

Furthermore, using the 20-point strapping table in the GWR transmitter, the vessel was accurately calibrated for tank volume.   This brought an additional advantage because the customer was then able to operate more efficiently, resulting in better control of the fermentation process.

By using ECLIPSE GWR technology, the customer has increased yield by about 20%.

Considering the cost of fermentation and production cycle of about one batch per week, the customer realized a payback period of less than two months.

Visit the Eclipse Model 706 microsite now!