In production, it is often necessary to measure the level of a liquid (water, gasoline, oil). In everyday life, most often it is necessary to determine the height of the water in any container; for this, special devices are used - level gauges and alarms. Measuring devices are divided into several varieties, they are purchased in stores, but for home use it is easiest to make a water level sensor with your own hands.
Content
- Types of sensors
- Selection rules
- DIY making
Types of sensors
Sensors differ in the way they measure the liquid level and are divided into two types: alarms and level gauges. The signaling devices track the set point of filling the container and when the required volume of liquid is reached, it stops flowing (for example, a float in a toilet bowl).
Level gauges continuously monitor the degree of filling of the tank (for example, a sensor on a mine drainage).
According to the principle of operation, the water level sensors in the tank are divided into such varieties:
- Float - their design includes a float with a magnet and two hermetic contacts (reed switches). When the minimum liquid level in the tank is reached, the float moves down and acts on the reed switch with a magnet, while the relay turns on and the pump starts, and water is pumped into the tank. When the tank is completely filled, the float reaches the upper reed switch, while the relay is activated, turning off the pump.
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Ultrasonic - are used not only in a liquid medium, but also in a dry one. The devices work in this way: the emitter sends pulses that reach the reservoir and return to the receiver. The built-in signal processing controller analyzes the strength and duration of the ultrasonic wave attenuation (these parameters are different for a full and empty vessel). - Electrode - used in liquid conductive media. They consist of two electrodes that control the required liquid level. The third electrode is emergency and is used when the set parameters are exceeded and the pumping mode is turned on.
- Radar - universal mechanisms due to the fact that they can be used when working with aggressive and explosive liquids. The principle of operation of the devices is based on the use of radio wave radiation - waves of a certain length are directed to the surface of the liquid process medium, are reflected from it and fall into the analyzer. The fill level of the container is determined by the rate at which the signal returns.
These are the most common level sensors, in addition to them there are capacitive, hydrostatic, radioisotope and other types of devices that are used in various industries.
Selection rules
When buying a liquid level sensor in a tank, several factors must be taken into account, if they are observed, the device will work correctly and without failure. First of all, you need to determine type of fluid and its density, the level of danger to humans. The material of manufacture of the container, its volume are important - the principle of operation of the selected sensor depends on these parameters.
The next point to pay attention to is purpose of the device, it will be used to control the minimum and maximum liquid level or to continuously monitor the filling of the tank.
When choosing industrial sensors, the number of criteria can be expanded; for household alarms and level gauges, it is enough to take into account the volume of the tank and the type of device. At home, hand-made devices are used - they work no worse than factory models.
DIY making
The easiest way is to make your own float water level sensor in the tank, or a filling indicator.
The principle of operation of such a device consists in the fact that the float floats in the liquid, at the maximum filling of the container, it closes the contacts and signals a sufficient water level.
Manufacturing sequence:
- Two caps from ballpoint pens are connected together and filled with glue - a float is obtained.
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The tube from the handle body is cut in half - the previously made float should easily enter it and move without restrictions. On one side, a transverse wire is attached in such a way that the float does not fall out of the body, but at the same time water enters inside without hindrance. - Two copper wires 5-7 cm long are stripped, a square piece of foil is attached to them (clamped with pliers). The foil with wires is glued to the base from the tube, and the top is closed with a cap.
- The finished sensor is lowered into water, the wires are connected to the sound signaling device. When the liquid level rises, the float floats up, closes the contacts, and a signal sounds.
The given sensor manufacturing scheme is the simplest; it is used for small containers.
The disadvantage of such a device is that it does not allow the automatic shutdown of the pump. To stop the supply of water to the tank, alarms are made using magnets and reed switches.
