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Operating principles of capacitance level sensors and application examples

As well as for measuring levels, our capacitance level sensor has been used in various other applications. Conventional capacitance sensors only detect liquids. However, our capacitance level equipment can be used for a number of applications. This page introduces the operating principles of capacitance level sensors and shows some application examples. If you are saying, We need a level sensor that can measure in our specific conditions, then count on us. We can provide devices that will meet any need, including the following.


Operating principles of capacitance level sensors

An electrode (sensor) has two poles: a detection electrode and grounded electrode. The meter detects the capacitance and conductivity between the two electrodes. An amplifier connected to the electrodes reports the amount of material and its status.

Advantages of capacitance type

  • The sensor can detect almost all forms of substances, including liquids and powders, as well as both conductive and insulating materials.
  • Not affected by temperature, pressure, or dust.
  • There are a wide variety of electrodes to allow the detection of different forms and materials. You can select from various models to match your conditions.
  • No moving parts and excellent durability.
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Application example・se the foliage of plants as a burglar sensor.

Please tell us about sensors that use capacitance technology

Level meters used in plant tanks are mostly made of stainless steel. We decided to design system using plant foliage as a sensor in order to identify an intruder trying to get into a house.
Conventional level sensors detects increase volume of capacitance between electrodes (made of stainless steel) and convert it to detection signal. This system use whole of foliage plants in lieu of electrode bars of a level sensor.
If a intruder comes close or touch the foliage plants, capacitance increases and the amplifier connected the foliage plants outputs detection signal and let light the alarm lamp. Even if there is no light in a room, change of capacitance by approximating an intruder to the foliage plants let alarm to emit.
You may imagine sensor is a component. But as far as object that can flow electricity, it can be a sensor. Plants contain water from its root the leaf tips so electricity flow over them.
Using this principle, we designed our burglar sensor.

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Application example・detect sauce

We are presently trying to detect a substance using an electronic camera. But we can’t get satisfactory result due to our harsh environment.
Please tell us an application example for detection using capacitance technology.

A. In a Natto (fermented soybean) production line, gravy is placed into a cup along the way as the cups are fed onto a conveyor.
In the production line, rarely gravy is not inserted into a cup. This company detected existence of accessory using an electronic camera. But they could not detect successively as the gravy has the same color as Natto.

Well, our ultra high sensitivity capacitance level sensor solved this problem.
In order to detect that sauce is correctly ladled into a cup, we set the sensitivity of the capacitance sensor to an ultra-high level and we were able to solve the problem.

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Application example・measure the powder level in a pressed powder supply mechanism

Can we measure the level of powder in a sealed container in harsh conditions involving a lot of flying powder and dust?

A. We managed to control the powder level using a capacitance level meter on the machine that dispensed the powder into a table type sealed container.
Person inquired once exiled level measurement using optical distance meter. However, doe to much influence of power dust, he gave up to use it. We solved this problem by design and produced special flat electrode as shown in figure 2, and measured change of capacitance without contact material.
We also looked into the design of a sensor shape that would not be affected by a rotating vane used for agitation of the material.

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