How It Works
A leak noise correlator is an electronic device used for Leak Detection and as a leak locator to find leaks in pressurized water.
Typically, microphones or acoustic sound sensors are placed in contact with the pipe, at two or more points, to record the sound emitted by a leak (e.g. a hissing noise) somewhere between the points. The sound data is processed through a mathematical algorithm which compares or correlates the two recordings to determine the difference in the times it takes noise to travel from the site of the leak to each of the sensors. If the distance between the sensors is known in advance, this timing information can be used to determine the location of the leak.Tracer Gas Detection
The tracer gas is introduced, from a cylinder of gas, into the water pipe with the suspected leak. The tracer gas used to find water leaks is a mixture of hydrogen (5%) and nitrogen(95%) making it completely safe to use in drinking water supplies being both non toxic and non corrosive. The tracer gas contains hydrogen, which is the the lightest and smallest molecule in the atmosphere, which will exit at the leak point and make its way to the surface where it is detected by the highly sensitive gas detector.Ground Microphone
When a pressurised water pipe leaks the water flows out which causes the pipe and surrounding material (mud, concrete tarmac) to vibrate. This sound, or vibration, is transmitted along the pipe, (structure borne water leak noise) and through the surrounding material (ground borne water leak noise).
Listening sticks, metal or wooden poles with ear pieces, are used by water leak technicians and have been used for centuries to listen for water leaks, they are, at best, only able to detect water leaks that are very loud. However, contrary to common perception, it is not always the largest leaks which are the loudest; often a large split in a water pipe produces less noise than one pouring through a small hole. This can be particularly true in non-metallic pipes. For this reason amplifying the water leak noise with an electroacoustic microphone, has become an essential tool for finding water leaks in networks and leaks in houses under concrete and wooden floors.Cable Locating Devices
These are designed to assist in avoiding buried cables and pipes during excavation, reducing the risk of injury to personnel and damage to utilities. Cable locating devices are designed to detect signals inherently radiating from metallic services, or from the complimentary range of Sondes (Mice) and accessories designed to enable the location of non-conductive services.
This tool is also used for survey work to locate run of pipes externally, to help water leak detection technicians to pinpoint more accurately.