1. Identity outside the computer room-tap water leakage detector

(1) Working principle: When the water supply pipeline leaks, the water sprayed from the pipeline rubs against the leak and collides with the surrounding medium, which will cause vibrations of different frequencies, and the leak detector of the heating pipeline will produce the sound of water leakage. In the damaged part of the pipeline, when water leaks, sound waves will be formed, which propagate to both sides of the pipeline in a sinusoidal manner, causing the pipeline to vibrate. At the same time, the fast-flowing water at the broken place will impact the medium around the pipe and produce a special frequency of water leakage sound. It is transmitted to the ground through surrounding media and pipelines. Look for leaks in the water supply network. It is the basic principle of leak detection to use the leak sound method to detect the leak points individually.

2) The types of water leaking sound can usually be divided into three types:

① Leakage friction sound: refers to the sound produced by the friction between the water sprayed from the pipeline and the leakage. Usually the frequency is 300 ~ 2500 Hz, which spreads far along the pipeline. The propagation interval is usually related to water pressure, pipe material, pipe diameter, interface, leakage shape and size, etc. Within a certain range, the sound of water leaking from exposed points such as doors and fire hydrants can be heard.

②Head impact sound: refers to the sound produced by the impact of the water sprayed from the pipe with the surrounding medium. It spreads through the soil to the ground in a funnel shape and can be detected by a leak detector or a listening rod on the ground. The frequency is usually between 100 and 1500 Hz. Tap water leak detector.

③Medium friction sound: refers to the sound produced by surrounding particles (such as soil particles, sand particles, etc.). ) The water sprayed from the pipes collides with each other, and the frequency is low. When the listening stick is inserted near the leak point. It can be audible, which provides a basis for the final confirmation of the leak. In the beginning, the commonly used leak detection equipment was to capture these three sounds. Accurately locate the leak point.

2. Computer Room-Leakage Detector

(1) Working principle: The water leakage detector in the computer room is composed of an induction cable for detecting liquid leakage and a controller with a positioning alarm. When a leak occurs, the sensing cable sends a signal to the controller. After being processed by the microprocessor, the leakage location is uploaded to the monitoring host through the communication protocol, and an alarm is issued at the same time. The induction cable is composed of four (or two) wires of different types, two of which are made of conductive polymer, and the resistance per unit length is precisely processed and fixed. When there is no leakage, the current value between the two wires is normal. When the induction wire is contaminated by leakage, the two conductive polymers are short-circuited, which changes the measured current value. According to Ohm's law, resistance is related to length, and the location of the fault leakage point can be obtained by calculation.

2) Water leak detectors in the computer room are usually divided into three types:

①Regional water leakage detector: low cost, high reliability, suitable for all kinds of places with water leakage risk. It can be connected with most water leakage alarm hosts, with high detection sensitivity. The response is fast and reliable. The induction wire is formed by pressing two lightweight high-density polyethylene wires around the central axis of the spiral. It has strong mechanical properties, corrosion resistance and wear resistance.

②Positioning leak detector: it can detect water at any position along the cable. The cable is installed with the leak controller. Once water ingress is detected. An alarm will be activated and the location of the leak will be accurately indicated.

③Point-type water leakage detector: a cost-effective water leakage detection device. Suitable for use with dual-core water leakage sensing cables, point sensors, and normally open dry contact devices. The leak controller is suitable for installation in conventional (non-hazardous) areas. The water leakage controller is equipped with two small LED indicators (respectively display power and communication activities) and SPDT contact relays. The water leakage controller can be used as an independent leak detection alarm unit. It can also be connected to the main control system (computer or control automation system) through a simple shielded twisted pair RS-485 serial communication wiring.