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Wednesday March 2 2022

Laser Silo Level Measurement Explained

Many industries rely on the bulk storage of raw materials used in manufacturing production, such as food processing, chemicals, and construction.

However, around 80 per cent of companies using silos continue to employ manual level measurement, with staff climbing to the top of a silo to estimate the volume of material within.

This process is both inaccurate and extremely inefficient and often leads to companies running out of raw materials, causing costly delays to operations. It also represents poor health and safety practice, by unnecessarily exposing workers to risk.

With advances in telemetry technology, far more effective ways of measuring silo levels have been developed and one of those is the use of lasers.

In this article, we take a look at laser silo level measurement and the advantages it can bring to manufacturing and production businesses.

How it works

Laser silo level measurement works by mounting a laser transmitter and receiver – often part of the same unit – at the top of the silo.

The transmitter produces a set high-frequency electromagnetic wave which rebounds off the product surface and is detected by a sensor to produce a reading of how much material remains in the silo.

Laser level measurement generally works in one of two ways. These are:

  • Confocal

Confocal transmitters are the most precise laser transmitters available. They work by emitting white light which is focused onto the target surface by a multi-lens optical system. These lenses separate the light into different colours, each with a different wavelength.

The volume of product in the silo is calculated in relation to the wavelength of light detected by the sensor as the sensor can only detect light that is perfectly in focus. This then calculates the distance to the target surface, and from this an accurate measure of how much material remains in the silo can be produced.

  • Triangulations

The triangulation measurement process is simpler than that of a confocal system. Here, the laser beam is transmitted onto the product surface and rebounds to the sensor.

The level of material in the silo is calculated by the time it takes for the signal to be detected by the receiver.

Laser transmitters can be set up to produce a broad laser beam for wider silos which is effective at measuring any banks in the stored material. This system employs multiple sensors to ensure the entire surface of the product is accounted for.

Laser sensors have also been used in complex processing plants where only a confined space is available to measure material levels. This might be where bin walls or other obstacles need to be avoided to ensure no false readings.

Benefits of laser level measurement sensors

Using lasers to monitor silo levels has many advantages. First of all, they are incredibly accurate with even the most basic systems able to measure accurately up to a tolerance of 1mm.

Laser transmitters and receivers are also relatively cheap and easy to install.

They can be used to measure a number of different materials, including solids, pelleted materials, liquids and gases. However, they are not recommended for powdered materials as they are affected by dust.

Lasers can work at long ranges, making them ideal for tall, industrial silos where the distance from the top of the silo to the target surface is great.

They are often employed for use with materials that are corrosive as they are unaffected by material type, and they can endure a huge range of temperatures, typically between -40oC to +50oC.

Finally, a major advantage of laser level measurement is that vibration from the silo while being refilled does not create false readings meaning the risk of overfill is reduced.

Remote monitoring

Another benefit of laser silo monitoring is that it can be paired with a remote measuring system, enabling silo operators to check silo levels from anywhere with an internet connection.

Remote telemetry is an extremely effective tool in inventory management and can bring huge efficiencies to a business in terms of procuring supplies of raw materials, removing waste products, and ensuring silos never run out of product, which could lead to a costly break in production.

Along with efficiencies, remote silo monitoring can also improve health & safety practices by reducing the number of vehicle movements at businesses or on construction sites, reduce the need for people to work at height to check silo levels, and even pave the way for night deliveries as silo refills can be monitored remotely.

Our remote telemetry system, MySilo, is compatible with laser measurement systems. It enables silo operators and owners to check the levels of all of their silos from anywhere, and give access to trusted partners such as suppliers, who can see when deliveries are required.

As well as this, it can be set to send alerts when silos contents reach a certain level, ensuring you can order a refill at the optimum time, maximising your inventory procurement and management process in one.

When it is used

Laser sensors are used in multiple industries, including plastic, food processing, construction, dam/reservoir water-level detection, sea/river level detection, rainfall level detection, mining, oil and gas, chemicals and even foam.

For companies that are “just in time” operated, laser monitoring, particularly when coupled with remote telemetry, enables them to make more informed decisions and forecast better to ensure production is continuous.


Although laser measurement has many advantages, there are some drawbacks too. As mentioned earlier, lasers are affected by dusty environments and instead of the electromagnet wave bouncing off the target surface, it can rebound off dust in the silo, giving a false reading.

Transmitters and sensors also need regular cleaning because if the lens system of a confocal system is dirty, it may not detect the correct wavelength of light and give a false reading as to the volume of the product in the silo.

Therefore, in a dusty environment, radar sensors tend to be favoured as these are unaffected by particles in the air.

For more advice on laser level measurement systems, remote silo telemetry, or any of your silo cleaning, maintenance or measurement needs, get in touch.

Want to learn more about the different types of sensors used to measure silo levels? See our complete guide How to Measure Silo Levels by Product Type which provides a great overview.