What Is an Automatic Level?
An automatic level refers to the measurement of the water level in a container, river, etc., or the height at which powder materials are stacked. Many measurement principles have been developed, and a variety of companies offer automatic level products. Some products combine the function of measuring the automatic level of the water level or height with the function of a switch to operate the appropriate equipment according to that level. Typical measurement methods include float, electrode, pressure, ultrasonic, laser, and capacitance.
Uses of Automatic Levels
Automatic levels are used in a wide range of applications from industry to public facilities, including industries that use tanks for storing liquids, facilities that manage rivers, etc., and water treatment plants. When selecting a method of automatic levels, it is necessary to consider the accuracy and detection speed of the measurement, whether the object to be measured is suitable for the measurement method, durability in the operating environment, ease of installation, and ease of maintenance.
The following are examples of automatic levels in use:
- Measuring the remaining volume in a water storage tank
- Measuring the degree of mixing in a chemical plant
- Control of water levels in dam management facilities
Principles of Automatic Levels
The following is a description of the measurement principles of automatic levels, divided into the typical measurement principles: float, electrode, pressure, ultrasonic, laser, and capacitance.
- Float Type
A float with a built-in magnet is placed on the water’s surface, and its movement is measured by the magnetic force generated by the magnet. - Electrode Type
Several electrode rods of different lengths are placed perpendicularly on the surface of the water, and the difference in the current-carrying capacity of the electrodes in the liquid and the air is used to determine roughly how much the automatic levels are. The measurement accuracy is determined by the number of electrodes. - Pressure Type
The level is estimated by installing a pressure gauge at the bottom of the tank and measuring the amount of pressure exerted by the liquid. The gauge must be installed before filling the tank with liquid. - Ultrasonic Type
The level is measured by irradiating ultrasonic waves toward the liquid surface and measuring the time it takes for the ultrasonic waves to reflect to the liquid surface. This is a non-contact measurement method. - Laser Type
The level is measured by irradiating a laser beam toward the liquid surface and measuring the change in phase of the returned light when the laser beam reflects off the liquid surface. This is a non-contact measurement method. - Capacitance Type
Level is estimated by placing electrodes in the air and the liquid, and measuring the difference in capacitance between the liquid and the air due to the difference in level.