Classification of water level gauges

There are two types of water level gauges, one is a "level gauge" and the other is a "level gauge." The following is a classification of water level meters.

(1) The principle of the float-type water level gauge is to sense the rise and fall of the water level by the float. A general water level meter that directly makes a float transmission recording structure with mechanical means has a teletype, a digital water level gauge that converts the amount of rotation provided by the float into an incremental electric pulse or a binary coded pulse for long-distance transmission, and also uses miniature floats and many Reed switch composed of digital water level gauges. The most widely used is the mechanical water level gauge. The application of float-type water level gauges requires logging equipment and is only suitable for use in river sections with stable slopes and low sediment concentration in riverbeds.

(2) Tracking water level meter, also known as contact water level meter, uses the electric stylus on the hammer to contact the water surface to send out electrical signals, so that the motor rotates forward or backwards and keeps track of the position of the water surface at any time, thus determining the water level. Iron pipes are generally erected on steep slopes, and the suspension hammers and suspension cables move up and down the pipes to drive recording or signalling devices. The inlet of the iron pipe needs sedimentation and still water facilities.

(3) Pressure-type water level gauge Its working principle is to measure the water pressure and calculate the water level. Its characteristic is that it is not necessary to build hydrostatic well logging. The sensor can be fixed at the bottom of the river and the pressure can be used to eliminate the atmospheric pressure so that the water level can be measured directly. There are two types of pressure level gauges. One type is a bubble type, which continuously delivers gas in a pressure-inducing tube, and converts the water pressure into a mechanical rotation amount using an automatically adjusted pressure balance, thereby driving the recording mechanism. The other type is the electrical test 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, transmit it to the shore for processing and recording (Figure 2).

(4) The sonic water level meter is a type of reflective water level meter. The application of sound waves in different interfaces reflects the water level. Divided into gas-type and water-type two types. The air-to-membrane type uses air as the sound wave propagation medium. The transducer is placed above the water surface. The sound wave is reflected from the water surface and the water level can be calculated and displayed according to the echo time. The instrument does not touch the water body, completely free from the influence of sediment, flow velocity impact and aquatic grasses and other unfavorable factors. The water type is to install the transducer on the bottom of the river and emit sound waves to the surface of the water. Acoustic waves travel in aqueous media at high speeds and distances and do not need logging. Both water gauges can be cabled to indoor display or storage records.