Magnetic Level Gauges in Process Control

A magnetic level gauge is a type of instrument that is used to measure the level of a liquid in a tank or process vessel. It works by using a magnetically coupled float that moves up and down along a calibrated vertical scale as the level of the liquid changes. The position of the float is indicated by a pointer or display that is visible to the operator.

In process control applications, the magnetic level gauge is used to monitor and control the level of liquids in tanks, vessels, and other containers. This is important for a number of reasons, including safety, efficiency, and product quality. For example, if the level of a liquid is too low, it may indicate a leak or a problem with the process. On the other hand, if the level is too high, it may indicate that the process is running too quickly or that there is a risk of overflow.

The magnetic level gauge is typically mounted on the outside of the tank or vessel, which allows the operator to easily monitor the level of the liquid without having to open the vessel or disrupt the process. Some gauges may also be equipped with alarms or automatic control systems that can shut down the process if the liquid level becomes too high or too low.

Overall, the magnetic level gauge is an important tool in process control, as it helps to ensure the safe and efficient operation of industrial processes that involve the handling of liquids.

For more information, contact Alliance Technical Sales. Call 630-321-9646 or visit https://alliancets.com.

Safe and Cost Effective Liquid Level Control with Magnetic Level Gauges and Magnetostrictive Transmitters

Magnetic level gauges are a safe, easy, and dependable way to measure fluid levels inside a tank. These visual indicators are a non-invasive, low-maintenance, cost-effective alternative to sight glasses. Because the fluid never comes into contact with the indicating glass, they are exceptionally safe for flammable, toxic, and corrosive liquids. There is no risk of leakage if the glass ever breaks. 

Magnetic Level Gauges (MLGs) are widely used in the monitoring and process control of liquid level and interface in various industries such as petroleum, chemical, power, paper, metallurgy, and water treatment. They are suitable for continuous process level measurement that is real-time, precise, safe, and dependable. 

The magnetic level gauge, bolted to the process vessel, provides real-time level and interface measurement based on magnetic coupling and buoyancy principles. IA float is inside the level gauge chamber with a 360° magnetic ring. An indicator with a vacuum glass tube containing a bi-colored two-face magnetic bargraph connects to the outside of the chamber. The float moves in response to the level change, causing the magnetic bargraph to turn and change color. Additionally, a mating magnetostrictive transmitter provides a continuous analog or digital output. 

The precise liquid level is displayed or "read." The indicator uses hermetically sealed glass tube technology to show the process level clearly. It eliminates, among other things, the common problems associated with glass gauges, such as vapor, condensation, and liquid leakage.

Most Common Applications for Magnetic Level Gauges:

• Boiler: Steam drum liquid level
• Power generation: Auxiliary machinery liquid level (HP reheater, LP reheater, de-aerator, 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.

For more information in Illinois, Indiana, and Kentucky contact Alliance Technical Sales. Call 630-321-9646 or visit https://alliancets.com.

Magnetostrictive Level Transmitter Retrofit to Magnetic Level Gauge

This magnetic level gauge has been fitted
with a magnetostrictive transmitter to
provide a continuous process level signal
Jogler

A magnetic liquid level indicator provides a reliable and highly visible reading of its indirect level measurement in tanks and vessels. While useful for local visual indication of tank level, the instrument does not provide an electrical signal output that can be utilized for process control or other monitoring functions. Several magnetic level gauge manufacturers offer combination units that incorporate another measurement technology to provide an analog signal corresponding to liquid level.

What if your installation has an existing magnetic level indicator and you need an analog level signal?

One manufacturer, Jogler, offers a magnetostrictive level measurement instrument that can be retrofitted to an existing magnetic level gauge, even those from other manufacturers. The low profile waveguide mounts slightly away from the existing magnetic level unit to isolate it from temperature and vibration. It is specifically designed for use with an existing magnetic level indicator and provides an analog output signal that is accurate, stable, and responsive.

A magnetostrictive level measurement instrument employs a magnetic float that moves along a sensing wire as the tank level changes. Fixed interval current pulses are sent down the wire, with the resulting electromagnetic field being interrupted by the magnetized float. This interruption causes magnetostriction in the sensing wire, which is manifested as a torsional stress wave along the wire. A piezoceramic sensing element converts the torsional stress into an electrical signal and the transmitter produces an output signal based upon the time interval between the initial pulse and the return pulse produced as a function of the float position.

There is more to be learned, so share your liquid level measurement requirements and challenges with instrumentation specialists. The combination of your process knowledge and their product application expertise will produce effective solutions.

Magnetostrictive level transmitter added to magnetic level gauge from Alliance Technical Sales, Inc.

When Magnetic Level Indicators May Be Best Choice for Tank Liquid Level Measurement

Magnetic level gauge configured for sanitary installation
Courtesy Jogler

Fluid process control operations often involve vessel or tank storage of liquids. Continuous and accurate indication of the liquid level within the tank is an essential data point for process control decision making and safety. Several methods and instrument types are available for tank level measurement, each with its own set of attributes that may be advantageous for a particular installation. Selection criteria for a tank liquid level indicator may include:

• Direct or indirect measurement of level
• Level measurement accuracy and reliability
• Tank shape, regular or irregular
• Media compatibility with measurement device
• Requirements for maintenance or calibration
• Compatibility with process temperature and pressure range
• Local display and visibility
• Level indication signal type and transmission
• Level alarm switches or other indicators

The selection of a magnetic level indicator, also referred to as a magnetic level gauge, for the project will likely be based upon at least one of the instrument's strengths. Magnetic level gauges have a host of potentially positive features for level indication.

• Continuous level measurement
• Operable without electric power
• Direct visual tank fluid level indication, regardless of tank shape or profile.
• Wide range of operating temperature and pressure
• Breakage resistant construction
• Range of construction materials available to accommodate corrosive media
• Measuring indicators, switches, and transmitters mounted externally, without contacting the medium being measured.
• Low maintenance operation.
• Readable level indication from greater distance than glass sight gauges.
• Applicable to large fluid level ranges with a single instrument.

Magnetic level indicators have a strong position in the tank liquid level measurement field and should be considered as a candidate for fulfilling those application requirements. There are many options available to customize the level indicator for each specific application. I have included a technical data sheet from Jogler, a manufacturer of level instrumentation, for more detail. Share your application challenges with a sales engineer that specializes in level measurement. Combining your process knowledge with their product application expertise will yield positive solutions.

Jogler magnetic level gauge brochure from Alliance Technical Sales, Inc.

Magnetic Level Gauges Superior to Glass Level Indicators

Magnetic Level Gauge
(courtesy of Jogler)

Magnetic level gauges isolate of the process inside of a sealed piping column, thus eliminating the possibility of leaking seals and cloudy or broken site glass. Magnetic level gauges (gages) allow for easy cleaning access and a wide variety of mounting styles and process connections. They also provide improved visibility with highly visible flippers.

Magnetic level gauges are designed with a float in a sealed tube, embedded with permanent magnets. As process level changes, the float rises and falls, and the magnets in the float couple with an external indicator. The indicator is completely isolated from the process.

The following video provides a brief overview of Jogler level products. Jogger is a Baton Rouge, Louisiana manufacturer of high quality magnetic level gauges, magnetostrictive transmitters, direct-reading level gauges with armored shield, sight flow indicators, specific gravity analyzers, point level switches and other accessories. Jogler products are custom designed to meet customer specifications and manufactured to applicable ASME B31.1 and B31.3 code requirements to ensure reliable operation and maintenance free design.