Showing posts with label level transmitter. Show all posts
Showing posts with label level transmitter. Show all posts

What Advantages Do Displacer Transmitters Have Over Differential Pressure Level Transmitters?

Displacer Transmitters
Displacer
Transmitter
(Magnetrol)
Many technologies have been available over the years have helped the process control industry with level measurement. From basic mechanical float-operated level switches, the process automation industry has been developing new technologies to make industry safer and more efficient.

An example of a "tried and true" technology that was commonly used in the process automation industry is the DP (differential pressure) level transmitter. First introduced in the 1950s, DP transmitters measures the hydrostatic (head) pressure of a liquid in a tank or vessel and interprets this as level, based on the density/specific gravity of the liquid and programmed in by the user. A newer, alternative technology to DP transmitters is the displacer level transmitter, a device also based on specific gravity. While they both are dependent on specific gravity, they are significantly different in areas of installation, accuracy, and maintenance requirement.

Application/Calibration

Applying a DP transmitter or displacer level transmitter requires experience and there are many factors to be considered. Here are a few:

DP transmitters use inferential measurement to determine level measurement from the hydrostatic pressure.  Despite requiring the specific gravity variable having to be programmed into the transmitter electronics, the level displacer transmitter is in contact with the process media and the level measurement is direct.

DP transmitters requires time consuming and expensive calibration/re-calibration if any of the set-up parameters change or if the same DP transmitter is used on different materials in the same tank.
Displacer transmitters only require two variables to be programmed (temperature and specific gravity), making it easier when running multiple products in the same tank.

Many displacer transmitters do not require liquid to be present for calibration. They are programmed (wet or dry) using software. A huge time and money saving over DP transmitters.

Mounting

The physical mounting of DP transmitters is limited, which can in some situations can become downright problematic. DP transmitters require (2) side-mounted entry locations on the vessel or tank, with one having to be near the bottom. As a general rule, the fewer the entry points of a tank or vessel, the better, because of leakage. Tank bottom entries all the more so.

Displacer transmitters are mounted to meet the requirements of the application and do not require a connection at the bottom of the tank.

Installation Cost

While DP transmitters have a lower unit cost, adding ancillary components such as tubing and heat tracing can quickly "level" the installation cost playing field. Furthermore, don't discount the time cost savings when setting up, calibrating and re-calibrating displacer transmitters.

Temperature Range

DP transmitters have a normal operating temperature of up to 250°F, with an upper limit of 650°F when special options are specified.

Displacer transmitter can be used up to 850°F, very helpful particularly with level measurement in a hot oil separator application.

There are many options and variants to accommodate industrial level applications. Share your level application challenges with instrumentation specialists, leveraging your own knowledge and experience with their product application expertise to develop the most effective solution.

Innovative Non-Contact Radar Liquid Level Transmitter

non-contact radar level transmitter for industrail process control
Pulsar R86 non-contact radar level transmitter.
Image courtesy Magnetrol
Level measurement of liquids and solids in containers, silos, tanks and other vessels is an essential part of many processing operations. Accurate and reliable measurement of solids or liquid level contributes to operational success, as well as enhancing safety, both of which contribute to the bottom line and successful operation.

Magnetrol, globally recognized innovator in flow and level measurement, incorporates years of experience into their latest version of non-contact radar level measuring instruments. The incremental improvements contribute to easier, more flexible installation and better performance.

The R86 is a 26 GHz level transmitter applicable across a wide range of requirements in many industries. Benefits of the 26 GHz radar signal, with its smaller wavelength, are a smaller antenna and improved 1mm resolution. The narrower beam from the antenna makes positioning the transmitter less restrictive, with easier accommodation for vessel fixtures or geometry. Advanced on board diagnostics supplement the improved performance and deliver the information needed to maintain proper operation and process visualization. A broad range of antennas and mountings are available for the R86, accommodating various tank sizes, fittings, and temperatures

More information on the Pulsar R86 is provided in the brochure included below. Share your level measurement challenges and requirements with a process measurement specialist. Employ the leverage of their product application expertise to your own process knowledge and experience to develop an effective solution.


Top End Guided Wave Radar Level Transmitter

guided wave radar level transmitter
Magnetrol's model 706 embodies the best of guided
wave radar level measurement.
Image courtesy of Magnetrol
The Eclipse Model 706 is Magnetrol's loop powered high performance guided wave radar level transmitter. It incorporates many of the company's latest innovations into a single instrument capable of meeting the demanding requirements of an array of industrial applications.

Product improvements include increased signal to noise ratio, suitability for use with low dielectric media, and the ability to deliver accurate indication under foaming, flashing, or other challenging conditions. An extended probe offering enables use in measuring interface, liquified gas, even bulk solids.

The instrument is suitable for overfill applications, and does not use algorithms to infer measurements in a dead zone that may occur near the top of the probe in some other designs. The Eclipse 706 delivers true measurement right up to the process flange. Upgraded electronics allow the unit to be pre-configured prior to shipment, if requested. Additionally, the widest range of communications options is available.

For more information, share your level measurement challenges with a process measurement specialist. Leverage your own process knowledge and experience with their product application expertise to develop effective solutions.


E-Book on Fired Heaters and Combustion Efficiency

industrial equipment in high power boiler room
Modern high power boiler room
Yokogawa, globally recognized leader in a number of process control fields, has authored an e-book which provides useful insight into how operators of combustion based equipment and systems can improve efficiency and enhance safety by employing modern technology.

[All quoted passages in this article are from the Yokogawa e-book]

The Yokogawa e-book Combustion & Fired Heater Optimization offers “an analytical approach to improving safe & efficient operations” related to the use of combustion & fired heaters in the process industries. Through presenting an overview of combustion sources, such as furnaces and fired heaters, the book states that while “fired heaters pose a series of problems from safety risks to poor energy efficiency,” those problems “represent an opportunity for improved safety, control, energy efficiency and environmental compliance.” Fired heaters “account for 37% of the U.S. manufacturing energy end use.” Tunable Diode Laser Spectrometer (TDLS) technology helps mitigate safety concerns by “measuring average gas concentrations across the high temperature radiant sections.”

The book states that the four main concerns applicable to fired heaters are asset sustainability, inefficient operations, the operator skillset, and safety and compliance. Outdated diagnostics and controls have placed unnecessary stress on operator response, making sustainability of fired heaters difficult. The emissions of fired heaters are generally higher than designed, and can be coupled with control schemes for firing rates little changed over the past 40 years. Operators, generally, lack a clear understanding of design, and even engineering principles of heat transfer are not typically included in education related to fired heaters. Confounding the situation further, “many natural draft heaters do not meet this [safety regulation] guideline with existing instrumentation and control systems.” These complications combine to form a noticeable problem Yokogawa’s technology hopes to address. The company notes how the fired heater relies on natural draft instead of forced air, meaning the heaters “typically lack the degree of automation applied to other process units in the plant.” Offering a full detail of both the control state of most fired heaters and their systems defines the process situation currently considered common in the field, while emphasizing high excess air as providing a “false sense of safety.”

The proposed TDLS system allows for the measurement of “both the upper and lower conditions in a fired heater” by “simultaneously controlling the fuel and air supply based on fast sample intervals.” Safer burner monitoring and heater efficiency results from the TDLS measurements of CO, CH4, and O2. The optimization of air flow control reduces “O2 concentration … from 6% to 2%” and increases the furnace’s thermal efficiency. Combustion control is achieved by managing fuel flow and the arch draft. The TDLS integrated system works in tandem with already established logic solver systems in the plant. The TDLS technology works as a non-contacting measurement with “full diagnostic capability” and offers “distinct advantages over single point in situ analyzers” via reduction of false readings. Specific gas measurements, fast response time, optical measurement technology, and “high and variable light obstruction” are featured components of the TDLS system highlighted to show the technology’s durability and flexibility. The longevity and reliability of the system is showcased by how the TDLS combustion management system has been operational in a major refinery since 2010. The percentage of excess O2 in sample fired heaters has decreased by 1% to 1.5%. Measurements by the TDLS system have been verified by other gas analyzers. The furnace conditions in the plant are more efficiently monitored and controlled. As a result, the furnace in the functional environment is “now near its optimum operating point, using minimum excess air.”
Yokogawa presents a process-related problem, then details the key points of the problem while unpacking the causes. The e-book introduces Yokogawa’s technology, explains the mechanics, and demonstrates how TDLS acts as a solution to the problem, supported by a tangible example. The book offers great insight for both the operational principles of fired heaters and a new technology designed to maximize efficiency in the control process.


The e-book is included below. More detail is available from product applicationspecialists, with whom you should share your combustion and fired heater related challenges. Combining your own facilities and process knowledge and experience with their product application expertise will lead to effective solutions.


Level Measurement Using Isolating Air Flow

illustrated diagram of instruments used for bubbler liquid level measurement
Bubbler method of liquid level
measurement is simple and reliable
Courtesy Yokogawa
Remotely utilized measurements of tank liquid level are common throughout the fluid processing industries. Various means of inferential or direct measurement are available, each with its own set of performance, maintenance, and cost attributes that may make it the preferred choice for a particular application.

Inferring liquid level using a hydrostatic pressure measurement is a simple, easy to implement strategy for delivering a continuous level signal to the process operating and control system. There can be situations where mounting the measuring gear near the bottom of a tank or other vessel may be impractical or undesirable. A pressure transmitter mounted low on a tank may expose it to damage from plant traffic or other physical hazards. It is also possible that the tank may not have a suitable fitting located low enough to provide the needed measuring range. Having a potential leakage point at a fitting low on the tank may also be undesirable. Another, and certainly not final, scenario would be an application involving a corrosive liquid which must not come in contact with the pressure sensor.

The bubbler method of liquid level measurement employs an arrangement that overcomes all of the previously mentioned impediments. It can utilize connections at the top of the tank, above the liquid level. The way in which the method works will keep the pressure sensor out of contact with the process liquid, providing isolation from potential corrosive effects.

The apparatus for level measurement using the bubbler method employs a simple dip tube that extends from the pressure sensor or transmitter to nearly the bottom of the tank or vessel. A small amount of purge air or gas continually flows through the dip tube and will bubble out the bottom of the tube. This dip tube arrangement essentially transfers the hydrostatic pressure at the bottom opening of the tube to the pressure transmitter, while the purge gas keeps the liquid from advancing up into the pipe. The bubbler can be used on atmospheric or pressurized tanks with a properly configured pressure or differential pressure transmitter.

Probably the most significant application point of the bubbler method that will distinguish its use from many other level measurement methods is the importance of maintaining air or gas flow in the dip tube. The flow provides isolation of the sensor, but the flow must also be set to a level that will not impact the pressure measurement in the tube itself. If the flow is excessive, backpressure in the tube can be offset from the level imparted by the tank contents, with the result being an incorrect measurement.

Below is an application note from Yokogawa, showing how their pressure transmitters and rotameters can be used to create the setup. Share your process measurement challenges and requirements with instrumentation experts, combining your own process knowledge with their product application expertise to produce effective solutions.






Summary of Technologies Used For Continuous Liquid Level Measurement in Industrial Process Control

non-contact radar liquid level transmitter
Non-contact radar liquid level transmitter
Courtesy Magnetrol
Automated liquid processing operations in many fields have requirements for accurate and reliable level measurement. The variety of media and application criteria demand continuous improvement in the technology, while still retaining niches for older style units utilizing methods that, through their years of reliable service, inspire confidence in operators.

Here is a synopsis of the available technologies for instruments providing continuous liquid level measurement. All are generally available in the form of transmitters with 4-20 mA output signals, and most are provided with additional outputs and communications. What is notably not covered here are level switches or level gauges that do not deliver a continuous output signal corresponding to liquid level.

Whether considering a new installation or upgrading an existing one, it can be a good exercise to review several technologies as possible candidates for a project. None of the technologies would likely be considered the best choice for all applications. Evaluating and selecting the best fit for a project can be facilitated by reaching out to a product application specialist, sharing your applications challenges and combining your process knowledge with their product expertise to develop an effective solution.

Displacer – A displacer is essentially a float and a spring that are characterized for a particular liquid and range of surface level movement. The displacer moves in response to liquid level, changing the location of a core connected to the displacer by a stem. The core is within a linear variable differential transformer. The electrical output of the transformer changes as the core moves.

Guided Wave Radar – A radar based technology that uses a waveguide extending into the liquid. The radar signal travels through the waveguide, basically a tube. The liquid surface level creates a dielectric condition that generates a reflection. Calculations and processing of the emitted and returned signals provide a measure of distance to the liquid surface. No moving parts.

Magnetostrictive – A method employing measurement of the transit time of an electric pulse along a wire extending down an enclosed tube oriented vertically in the media. A magnetic float on the exterior of the tube moves with the liquid surface. The float’s magnetic field produces the return signal to the sensor. Processing the time from emission to return provides a measure of distance to the liquid surface.

Pulse Burst Radar - A radar based technology employing emissions in precisely timed bursts. The emission is reflectex from the liquid surface and transit time from emission to return is used to determine distance to media surface.  Not adversely impacted by changes in media conductivity, density, pressure, temperature. No moving parts.

Frequency Modulated Continuous Wave Radar – Another radar based technology that employs a radar signal that sweeps linearly across a range of frequencies. Signal processing determines distance to media surface.  Not adversely impacted by changes in media conductivity, density, pressure, temperature. No moving parts.

RF Capacitance - As media rises and falls in the tank, the amount of capacitance developed between the sensing probe and the ground reference (usually the side metal sidewall) also rises and falls. This change in capacitance is converted into a proportional 4-20 mA output signal. Requires contact between the media and the sensor, as well as a good ground reference. No moving parts.

Ultrasonic Non-Contact – Ultrasonic emission from above the liquid is reflected off the surface. The transit time between emission and return are used to calculate the distance to the liquid surface. No contact with media and no moving parts.

Differential Pressure – Pressure sensor at the bottom of a vessel measures the pressure developed by the height of the liquid in the tank. No moving parts. A variation of this method is often called a bubbler, which essentially measures hydrostatic pressure exerted on  the gas in a tube extending into the contained liquid. It has the advantage of avoiding contact between the measuring instrument parts, with the exception of the dip tube, and the subject liquid.

Laser - Probably one of the latest arrivals on the liquid level measurement scene, laser emission and return detection is used with time interval measuring to accurately determine the distance from the sensor source to the liquid surface.

Load Cell - A load cell or strain gauge can be incorporated into the support structure of the liquid containing vessel. Changes in the liquid level in the vessel are detected as distortions to the structure and converted, using tank geometry and specific gravity of the liquid.

All of these technologies have their own set of attributes which may make them more suitable to a particular range of applications. Consulting with a product specialist will help determine which technologies are the best fit for your application.


Electronic Displacer Liquid Level Transmitter - How it Works, When to Use It

Displacer liquid level transmitter diagram
Electronic displacer liquid
level transmitter using spring
technology
Courtesy Magnetrol
An electronic displacer liquid level transmitter is intended for industrial applications requiring the continuous measurement of liquid level in a tank, vessel, or other containing space.

Magnetrol, a globally recognized leader in the design and production of level measurement instrumentation, describes the operating principle of their Digital E3 Modulevel® displacer level transmitter:
Electronic displacer level transmitter technology operates by detecting changes in buoyancy force caused by liquid level change. These forces act upon the spring supported displacer causing vertical motion of the core within a linear variable differential transformer.
The movement of the core within the LVDT generates an electrical signal which is further processed and serves as the output of the transmitter. The unit is designed to be externally mounted on a tank. Isolation valves are recommended.

The spring technology employed as a counterforce to the buoyancy of the displacer results in a stable signal that is not impacted greatly by vibration, agitation, or turbulence of the measured liquid.

The video below provides more detail, covering the features and advantages of this level measurement technology and the Magnetrol instrument. Share your level measurement challenges and requirements with a product application specialist. The combination of your process knowledge and their product application expertise will produce effective solutions.

Low Cost Radar Level Transmitter For Industrial Process Applications

non-contact pulse burst radar technology industrial process level transmitter
Magnetrol Model R82 Radar Level Transmitter
With its ability to reliably detect tank liquid surface level under conditions that prove challenging to other methods, radar technology generally provides an operational advantage over other non-contact level measurement options. Historically, the cost of radar level transmitters for industrial process control applications has hindered their success as a unit of choice for some installations. Magnetrol has changed that imbalance with their recent introduction of a lower cost radar level transmitter for tough applications.

The Model R82 provides radar performance at a price point comparable to competitive ultrasonic units, but maintains the performance advantage inherent in a radar based device. The unit utilizes pulse burst radar technology at 26 GHz, employing advanced signal processing to filter out false echos produced by a range of in-tank conditions that can produce false readings from ultrasonic units.

The short video below provides a closer look at the R82 and its performance advantages. Technical data sheets and any application assistance you may need is available from product specialists. Share your level measurement and control challenges with them and work toward the best solution.

New Product - Model R96 Non-Contact Radar Level Transmitter

Non Contact radar level transmitter Magnetrol
New Model R96 Non-Contact Radar
Level Transmitter
Courtesy Magnetrol International
Magnetrol is a well known manufacturer of level and flow measurement instrumentation for the industrial process control field. The company recently released the Model R96 Non-Contact Radar Level Transmitter for applications where continuous fluid level measurement is required.

The company's description of the product...
"Virtually unaffected by the presence of vapors or air movement within a vessel’s free space, the two-wire, loop-powered, 6 GHz Radar transmitter measures a wide variety of liquid media in process conditions ranging from calm product surfaces and water-based media to turbulent surfaces and aggressive hydrocarbon media."
 The new product offers features that combine to make a state-of-art instrument for accurate continuous level measurement. A product brochure is included below. Contact application specialists to formulate the right product configuration for your level measurement challenge.




New Level Transmitter From Orion Instruments

Orion magnetostrictive level transmitter
Direct insertion and external mount versions of
Orion JM4 Magnetostrictive Level Transmitter
Courtesy Orion Instruments
Orion Instruments, a world class manufacturer of magnetic level indicators, level switches, and level transmitters, has released a new product for use in the industrial process measurement and control field. Their Jupiter Model JM4 magnetostrictive transmitter incorporates the company's many years of research, development, and field experience to provide a safer, simpler, and smarter transmitter for liquid level measurement and control.

The new model from Orion boasts level measurements with accuracy as high is +/-0.05" (1.27mm). The transmitter head can be rotated up to 310 degrees with an option for remote mounting. Variants are available for direct insertion or external mounting, with approvals for a number of area classifications. There are other valuable features to this series of level measurement instruments that reflect Orion's expertise in the field.

Browse the new product brochure included below. It provides illustrations of the product and its operating principle, along with dimensioned drawings and a listing of all the product options and variants. You can always obtain whatever information you need about Orion level measurement instruments from a product specialist. Share your liquid level measurement challenges and requirements with them for recommendations on the best solutions.