"Bubbler Method" Liquid Level Measurement

Brooks Instrument Solid Sense II pressure transmitter for industrial use
An accurate pressure transmitter
is an integral part of  a liquid level
measurement system using the
"Bubbler Method"
Courtesy Brooks Instrument
Measuring liquid level in a tank or vessel can be accomplished in a number of ways, all of which require some arrangement of instrumentation to either infer the liquid level from the measurement of a related physical property, or directly deliver the liquid level visually using a scaled gauge arrangement. One indirect method of level measurement is often referred to as the bubbler method, so named because it employs a purging gas that continually vents from the bottom of a tube extending into a tank of liquid. Through a simple apparatus, the level of a liquid can be inferred by the amount a back pressure exerted upon the gas flowing through the tube.

Probably the greatest advantage of this method of liquid level measurement is that the liquid does not contact the sensing instrumentation. The only portion of the apparatus in contact with the liquid is a tube immersed into the tank. Basically, a purge gas flows through the immersion tube and may bubble out the immersed end of the tube, which is open to allow the contained liquid to exert a hydrostatic pressure on the purge gas. The back pressure on the gas that is exerted by the liquid contained within the tank will vary directly with the depth of the liquid. The back pressure can be correlated to a liquid level. Further calculations, which would include the tank shape, dimensions, and the liquid density can provide an indication of the volume and mass of the liquid. Here is an illustration of the setup, provided courtesy of Brooks Instrument, globally recognized leader in flow and pressure measurement and control. The illustration is from Brooks' January blog article.


diagram of bubbler method tank level measurement apparatus setup
Bubbler Method Tank Level Measurement Apparatus, showing application of some Brooks Instrument devices.
Below are data sheets detailing the components used in the system to control and measure the gas flow, and measure the back pressure on the immersion tube. There are other components needed for a complete system, but they are fairly generic in nature and easily obtainable. Contact a flow and level measurement specialist with your application challenges and work with them to 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.

Yokogawa Users Conference and Exhibition is Coming

Yokogawa is presenting its 2016 Users Conference and Exhibition in Orlando, Florida. The event runs from October 3 through October 6 and will be held at the Renaissance Orlando at SeaWorld hotel. Included in the conference agenda are informative technical sessions, training workshops, panel discussions, hands-on demonstrations, essential application sessions, and daily keynote speakers. The opportunities for networking and learning are truly unique and rewarding for those involved in process automation and control.

There is currently a call for presentations, seeking out those who wish to share their applications and challenges. Learn more about the conference and register at the event website.



Yokogawa Publishes New Collection of Case Studies in Process Automation and Control

Yokogawa, an internationally recognized process automation and control provider, strives for customer satisfaction through operational excellence, bringing long-term success to its customers. Now available are collections of actual cases in which Yokogawa helped leading companies in a variety of industries address specific challenges and achieve their goals. The new e-books were redesigned and subdivided into six sectors including LNG, Oil & Gas, Chemical, Pharmaceutical, and Renewable Energy.

Browse the e-books online for insight into the breadth and depth of Yokogawa's capabilities and their commitment to their customer's success. Depending on your screen size, you may need to scroll down the page to see the e-books at the link. At e-books, you can browse using the online reader, or download them as a PDF file.

Share you process control challenges with a Yokogawa representative and expect the best solutions.

Save Time And Get The Right Product With Yokogawa Automated Selection Tool

Yokogawa Corporation of America, an industry recognized source for innovative process measurement and control products, has made available an easy to use product selection tool for those navigating through the company's extensive product offering. The Product Finder is a great time saver that enables a user to quickly locate product and technical information on Yokogawa process instrumentation products meeting the user's selected criteria.

Let's step through a quick example. You will see how this quick and easy to use tool saves time by navigating quickly to the website pages detailing products meeting your requirements.

The Product Finder is accessible through a number of links throughout Yokogawa's network of representatives. Clicking the link lands you on the start page of the Product Finder. For this example, I am going to search for a flow meter with the following characteristics:


  • Mass flow measurement 
  • Non-conductive liquid
  • Accuracy of 1%
  • Flow measurement device must have an integral transmitter
  • Tri-clamp connections



Above, I declared my location as United States. The next step, shown below, is to select "Flow" as the measurement parameter. You will see in the drop down menu that there are many measurement elements that can be selected, with Yokogawa products for each.


My selection of "Flow" from the drop down menu returns all of the company's flow measurement devices, of which there are many (this cropped screenshot, shown below, only shows four, but there were many more) . This is where the selector really helps you. Instead of examining several or many different models, the user can focus the search by adding more product characteristics. You can see the list of prompting questions on the left side of the page. Providing additional characteristics by answering the prompting questions will narrow the search results to the show only the products meeting all the criteria specified by the user.



The next image (below) shows all of my sample product attributes entered on the left column. Note that there is now only a single product that matches all of my sample criteria. The whole process took less than two minutes. By clicking on the "View More Details" button below the product image, I gain access to all of the available technical, support, and product data for my selected flow measurement device.


The process instrumentation specialists at Miller Energy are available to provide additional help in meeting your measurement challenges. Combine their product knowledge and expertise with your process know-how for the best solutions.