Why not catch changes in the water surface in real time and prevent problems before they occur?

This time, we'll introduce a "water surface sensor (liquid level sensor)" that allows you to measure distance quickly and easily.

"We want to check the water level in tanks and reservoirs in real time without having to go to the site." This challenge is common in a wide range of settings, from factory fuel tanks and agricultural water storage tanks to municipal sewage systems and food and beverage facilities. By combining water level sensors with wireless communication, remote monitoring that does not rely on visual inspections can be realized at a realistic cost.

In recent years, sensor technology has advanced remarkably, attracting attention from many industries. In particular, new sensors have emerged that can perform well even in situations where conventional sensors were difficult to measure, such as in dark places or dirty environments. They can measure even at night and have a certain degree of resistance to adverse weather conditions such as rain and fog, as well as environments where the casing may become dirty, enabling safer and more efficient operation.

the Company experiments have confirmed the performance of this sensor under various conditions, including differences in reflection depending on the material and transmittance when there are obstructions. These results suggest a wide range of applications. For example, this sensor can be used in environments where it is dangerous for humans to take measurements or where it is difficult to even go to take measurements, such as chemical management in chemical plants, monitoring of sewage systems under manholes, and even monitoring of rivers and lakes. Because the housing does not require a window for the sensor, it is less affected by rainwater and condensation and can be used safely even in dark places.

Macnica Manufacturing Consulting (MonoCon®) offers a "water surface sensor" that is easy to use and allows for immediate experimentation. In addition to the features, track record, and experimental data of this sensor, we will introduce specific examples of how this technology can contribute to our lives and businesses.

Water Level Sensor Overview

The water surface sensor we are introducing today boasts low power consumption, long-range distance measurement capabilities, and excellent environmental resistance (waterproof and dirt-resistant), making it suitable for use in a wide range of applications. Furthermore, it offers high detection accuracy for water surfaces and enables real-time data provision from remote locations via wireless communication, so its use in IoT-related applications is expected to increase in the future.

Recently, there was news of a manhole being blown off by a sudden downpour. This accident, caused by the air hammer phenomenon, could have been detected in advance if the sewage level from the manhole had been monitored in real time. (For example: Install a water level sensor behind the manhole and save the water volume data to the cloud every 10 minutes.)

Furthermore, this water level sensor can also be used for monitoring river flooding. For example, by installing it under a bridge and notifying the local government when the water level exceeds a certain value, a system can be created that allows for remote monitoring of conditions in mountainous areas. This helps to mitigate the risk of natural disasters.

From a privacy standpoint, this sensor is excellent. It can be used in places where cameras cannot be installed, and is expected to be useful in areas where monitoring is necessary while respecting individual privacy, such as bathrooms and toilets. Furthermore, it reacts not only to pure water but also to soups and other liquids, and is resistant to steam and oil fumes, so it is likely to contribute to the advancement of digital transformation in the food and beverage industry.

Furthermore, the fact that it can be retrofitted to existing equipment is a major advantage. For example, it could be used to monitor ballast water on ships, acting as a level switch. Its ease of installation lowers the barrier to adoption.

It can be used for monitoring household kerosene tanks and chemical tanks in plant factories. It can detect the liquid level beyond resin. There is no need to consider sealing the sensor mounting hole, and since detection is possible through caps and ceilings, explosion-proof measures are simplified.

Potential use cases for water surface sensors

The water surface sensor overcomes the weaknesses of conventional sensor technology and is capable of providing reliable data even under harsh conditions, making it suitable for use in a variety of industries. This sensor offers a worry-free solution by performing well even in harsh environmental conditions.

Installation locations that require waterproofing

One of the features of this sensor is that it does not require a window, which is unique to optical sensors. In other words, there is no need to drill holes in the housing, which has the advantage that it is possible to create a housing with high waterproof reliability. The sensor introduced here has waterproof performance equivalent to IP67, so it can be installed in outdoor environments such as rivers, lakes, and rice paddies, and will continue to operate without failure even if it is exposed to splashes of water, rain, or snow.

Another major benefit is the high degree of freedom in the design of the housing, which allows for flexible designs that suit a variety of installation conditions and meets the needs of users who also place importance on the appearance of the product.

[Expected installation location]
・Rivers
・Swamp Lake
・Rice fields
・Locations at risk of flooding

Nighttime or pitch black spaces

It is possible to perform stable measurements 24 hours a day, 365 days a year, regardless of lighting conditions. This characteristic makes it suitable for use in nighttime surveillance and low-light environments. It is possible to perform accurate measurements even in nighttime environments without street lights, and can be used without problems in pitch-black spaces where no light normally enters, such as sewers and fire-fighting water tanks.

[Expected installation location]
Sewerage
・Fire water tank
・Nighttime surveillance equipment

Easy to install on existing equipment

This dirt-resistant, durable sensor delivers consistent data even in harsh environments. The casing has a certain degree of resistance to dirt, rain, wind, steam, condensation, etc.

This characteristic is also an advantage because it can be installed on existing facilities, such as the lid of an outdoor water tank, and can be put into operation immediately. Installation is simple, which also leads to reduced implementation costs.

[Expected installation location]
・Factory/Plant Chemical tank
・Outdoor water tank
Breweries
・Ships (ballast water)

Measurement examples at the Company

the Company measurements show good results for water surface detection.

Below is the simplest measurement. No special settings are required, so anyone can operate it easily. The distance from the sensor to the water surface is measured, and the obtained distance measurement data is graphed. As a result, the distance from the sensor installation point to the water surface was captured with high accuracy, with an error of about 10 mm.

Furthermore, we conduct experiments under a variety of conditions.
If you are interested, please also take a look at the related articles below.

>> [Water surface sensor] Can the water surface be detected through a wall?
We conducted an experiment to see whether the water surface could be detected correctly even when there was a wall (obstruction) between the sensor and the water surface.

In addition, we are evaluating various other use cases, such as measuring the remaining amount of kerosene or a pot, and whether measurements can be taken even when the sensor casing is dirty.

How to use water level sensors and weight sensors

Up to this point, we've mainly discussed the advantages of water level sensors, but it's a mistake to assume that a water level sensor is the only option. Depending on the properties of what you're measuring, a weight sensor is often more suitable.

Case Study 1: Remotely monitor the remaining amount of soup → A weight sensor is advantageous.

One facility requested a solution to remotely monitor the remaining amount of soup. Initially, a liquid level sensor was considered, but due to the mixing of ingredients, the liquid surface became uneven, and hygiene concerns were also a factor. Therefore, a weight sensor (mat type) was proposed, which is placed under the equipment and measures the remaining amount by measuring the change in weight. This configuration is not affected by the shape of the liquid surface and does not touch the inside of the container, making it easy to handle from a hygiene perspective.

Case Study ②: We want to detect the remaining amount of a transparent drink → Optical and color sensors are not suitable.

We received a request to remotely monitor the remaining amount of drinks in a beverage dispenser from a control room and replenish them before they run out. We considered using cameras and color sensors for detection, but transparent liquids are difficult for color sensors to distinguish, and millimeter-wave radar is expensive. Here again, considering the balance between the properties of the liquid and the cost, weight-based detection became the most practical solution.

Guidelines for choosing between them

"Do you want to measure through a wall?", "Is it difficult to read the liquid level due to ingredients or transparency?", "What level of hygiene is required?" -- Clarifying these points first will ensure you select the correct method. For a detailed approach to remaining volume management, see below.Automatic inventory and remaining quantity management using weight sensors and IoT.Please also see the following.

Installation patterns based on different installation environments

The method will vary not only depending on "what you are measuring," but also on "where you install it."

Among these, underground structures (manholes, underground tanks) present the most challenging installation environments, as they simultaneously address three issues: communication, battery life, and waterproofing. MonoCon® can handle all three of these issues in a single design, providing comprehensive support from proof of concept (PoC) to mass production.

• Problem ①: Radio waves do not transmit well. Metal manhole covers significantly attenuate radio waves, and even if communication is possible on the ground, it may become impossible after installation. → Selecting a communication module (LTE Cat.M1/NB-IoT), arranging antennas to efficiently radiate through the gaps in the cover, and using burst transmission will increase the success rate. To prevent situations where "communication is OK outside but becomes impossible after installation," it is necessary to readjust the antenna and communication parameters to suit the site.
  
  
• Challenge ②: Make the battery last for years. There is no AC power supply, and frequent battery replacement is impractical. LTE consumes a large instantaneous current during transmission, so a method to reduce average power consumption (NB-IoT), a capacitor to support the instantaneous current, sleep control, and a boost circuit design are required.
  
  
• Challenge ③: IP67 or higher waterproofing. High humidity constantly presents a risk of condensation and water ingress. This can be addressed with a waterproof enclosure (potting, waterproof connector). The water level sensor introduced here can measure through the enclosure, thus avoiding the waterproofing challenge.

FAQ: Frequently Asked Questions about Water Level Sensors and Remote Liquid Level Monitoring

Q1. Can a water level sensor really detect the liquid level through a wall?

Yes. It can detect the liquid level inside containers by penetrating the walls of non-metallic materials such as plastic and FRP. We have actually conducted experiments to confirm penetration through different materials (vinyl, cloth, wood, resin, acrylic, and metal) and have published the results. However, it does not penetrate metal containers, so some ingenuity is required for installation. For details, please see "Can the liquid level be detected even through walls?".

Q2. Can a water level sensor measure anything?

No. Accuracy decreases under conditions such as ripples on the liquid surface, mixing of ingredients, or metal containers. For soups with high-salt ingredients or the remaining amount of clear drinks, a weight sensor may be more suitable. The method used depends on the properties of the liquid.

Q3. Can I communicate via LTE from inside a manhole?

It depends on the environment. Metal covers significantly attenuate radio waves, but we have a track record of ensuring communication by optimizing antenna design to remove radiation from gaps and vents in the cover. We recommend conducting a radio wave environment survey beforehand.

Q4. How long does the battery last?

It depends on the measurement and transmission frequency. For example, transmitting once an hour makes it technically possible to achieve battery life for years. However, this requires a power supply design that can handle the instantaneous power consumption of LTE, and cannot be achieved simply by connecting a general-purpose battery.

Q5. Can it be retrofitted to existing tanks or aquariums?

Yes. Retrofitting is possible simply by installing sensors on the outside of containers or inside existing manholes; no structural changes are required. For situations where you don't want to touch the inside, such as food processing equipment, you can also choose retrofitting with weight sensors.

Services provided by Monocon® (Manufacturing Consulting)

Even if an application seems to be measurable, it is affected by the surroundings, so we recommend that you actually measure it. Knowledge acquired from the web is often not applicable. Also, the subject is not limited to the water surface.

example)
Q. Can snow accumulation be measured?
A. Compacted snow can be measured. New, fluffy snow requires further investigation.

In the case of measuring snow, there were some issues that became apparent only after the actual measurements were taken, such as "detection accuracy changes too much over time." We will support you in carrying out pre-implementation verification by assuming various use cases.

At Monocon®, we would like to conduct experiments with people who are interested in this technology. We are also happy to discuss detailed data and experimental conditions, so please feel free to contact us.
*Please note that as this is a service aimed at businesses, we cannot respond to inquiries that do not apply to our services.

Related article

We conducted an experiment to see if the water surface could be detected correctly even when there was a wall (obstruction) between the sensor and the water surface. We believe that by conducting a verification in an environment close to the real thing, you will be able to get a more concrete image.

[Water level sensor] Can the liquid level be detected through a wall?