Float-type water level gauge
The principle is that the float senses the rise and fall of the water level. There are ordinary water level gauges that use mechanical methods to directly use the float to drive the recording structure, telex and digital water level gauges that convert the rotation angle provided by the float into incremental electrical pulses or binary coded pulses for long-distance transmission, and digital sensor water level gauges composed of miniature floats and many reed switches. The most widely used is the mechanical water level gauge. The use of float-type water level gauges requires logging equipment and is only suitable for low-sediment river sections with stable bank slopes and small riverbed erosion and siltation.
Fiber optic water level gauge
The fiber optic water level gauge includes a water level gauge sensor part and a control circuit terminal part. Among them, the water level gauge sensor part uses an optical path coupling adjustment device to connect with the optical cable to transmit the optical signal carrying the water level information. The control circuit terminal part uses laser modulation technology to send modulated laser signals with different functions. Through modulation, comparison and detection, accurate information on the water level is obtained. This principle realizes full-range optical measurement, and no charged devices are used outdoors, which can eliminate static electricity hazards and prevent lightning strikes.
Tracking water level gauge
Also known as contact water level gauge, it uses the electric probe on the heavy hammer to contact the water surface to send out an electric signal, so that the motor rotates forward or reverse, and tracks the position of the water surface point at any time to determine the water level. Generally, an iron pipe is set up on a steeper bank slope, and the hanging hammer and the suspension cable rise and fall in the pipeline to drive the recording or signal device. The water inlet of the iron pipe needs to have sand settling and static water facilities.
Pressure water level gauge
Its working principle is to measure water pressure and calculate water level. Its characteristics are that it does not need to build a static water logging well, the sensor can be fixed on the bottom of the river, and the atmospheric pressure can be eliminated by the pressure pipe, so as to directly measure the water level. There are two types of pressure water level gauges. One type is the bubble type, which continuously supplies air in the pressure pipe, and uses an automatically adjusted pressure balance to convert the water pressure into a mechanical rotation angle, thereby driving the recording mechanism. The other type is the electrical measurement type, which uses a solid-state piezoresistive device as a sensor, which can directly convert the water pressure into a voltage modulus or frequency output, and transmit it to the shore for processing and recording by wire.
Acoustic water level meter
It is a kind of reflection water level meter, which uses the principle of sound wave reflection on different interfaces to measure water level. It is divided into two types: air medium type and water medium type. The air medium type uses air as the propagation medium of sound waves. The transducer is placed above the water surface, and the sound waves are reflected by the water surface. The water level can be calculated and displayed according to the echo time. The instrument does not contact the water body and is completely free from the influence of adverse factors such as mud, flow velocity impact and aquatic plants in the water. The water medium type is to install the transducer at the bottom of the river and emit sound waves to the water surface. The propagation speed of sound waves in the water medium is high and the distance is large, and there is no need to build a logging well. Both water level meters can be transmitted to the indoor display or storage record by cable.