A Best Practice Guide to Calibrating Level Transmitters

Optimal performance of a level transmitter is critical in any industrial operation that involves storing bulk quantities of fluids or fluidized solids. To maximize the performance of their systems, companies must understand – and utilize – leading calibration techniques.

Calibrating level transmitters will help protect against problems related to the accounting of materials and against damage to tanks and pumps that incorrect measurement can cause.

Let’s outline some best practices for calibrating level transmitters.

Calculate the Differences Between Your Test Fluid and Your Process Fluid

For the vast majority of applications, companies will not be using their process fluid to complete the calibration work. In some cases, the process fluid is unsuitable for testing. In other cases, the fluid might be wasted during the testing procedure, and so the company will use water or another less expensive fluid to complete their calibrations.

Each level transmitter will be set by its manufacturer for a fluid-specific gravity. This means companies must calculate the difference in buoyancy between the fluid they use in their processes and their test fluid. The typical calculation for this range would be the following:

process fluid specific gravity / water specific gravity x transmitter level range

Determine Acceptable Tolerance Level

In beginning the calibration work, it’s important to understand the acceptable tolerance level for the process. One of the benefits of specifying a tolerance level at the inception of calibration work is that it allows team members to work within these parameters. This can help eliminate many of the mistakes made when calibrating level transmitters and can act as a guide for equipment performance moving forward.

Use a Leading-Class Isolation Valve

A high quality isolation valve enables operators to ensure optimal process effectiveness during their calibration work. It’s important that the isolation valve chosen has the ability to clean the process lines between the tank and the transmitter both before and after calibration has taken place. This helps maximize timing efficiency during calibration and ensures that results of the calibration meet the highest standards of measurement accuracy.

For pulp and paper mills running calibration processes according to ISO certification standards on a regular basis, it’s also imperative that the isolation valve can be closed during calibration work.

Skilled Technicians Must Assess All Factors That Can Affect Measuring

Accurate level measurement is absolutely crucial. Incorrect measurement can cause all manner of problems – overflow, pump problems, pump failure, leak of hazardous materials into the environment, etc. To measure and calibrate correctly, an industrial organization must be confident it has skilled technicians who will always make the correct calculations allowing for the many possible variables. Measurements can vary wildly according to the physical state of the substance – liquid, slurry or solid – and be affected by temperature changes, pressure changes, agitation levels, density, vibration, shock, noise, even by the shape of the tank. Best practice demands that the best technicians be used.

Effective level transmitter calibration empowers a broad range of industrial organizations to improve the performance of their systems. By following these guidelines, and speaking with trusted calibration specialists, firms can secure their process integrity over the long-term.

Creative Commons Attribution: Permission is granted to repost this article in its entirety with credit to indu-tech and a clickable link back to this page.

Leave a Comment