- The SePem system comprises the SePem 01 Master receiver as well as any number of data loggers; the SePem 100s are preferable for mobile use whereas the SePem 150s are designed for permanent use. They are magnetically attached to valve rod extensions, or to hydrants or other fittings in the pipe network. The microphone integrated in the logger converts the structure-borne noise in the line to a sound signal. This is cyclically recorded during times of low consumption – usually during the night between approx. 2:00 am and 4:00 am, when there is very little sound interference in the surrounding area, if any. On a leak-free line the noise level measured during this time is virtually zero. If there is a leak in the pipeline, the noise logger will measure values much different to zero, thus indicating a leak.
- The SePem 100 data loggers with integrated aerial are perfect for mobile use in the water pipe network. They are placed on fittings at measuring points in a specified section of network and record the level for a programmable period of time during the night – usually half an hour. The loggers are collected in the next day. The measurement data is transmitted to the SePem® 01 Master by radio. Noticeably high measurement values indicating a leak are immediately flagged up by an audible signal. This is a reliable way of detecting existing leaks. The data loggers are then successively inserted in other sections of the network until the whole network has been checked.
- The SePem 150 data loggers are designed for the stationary monitoring of water supply networks. They have an external aerial and are permanently fixed to fittings. The SePem® 150s record the minimum level every night for a programmable period of time, for example half an hour. The locations are periodically patrolled, for instance daily or weekly, when the noise loggers send their data telegrams to the SePem® 01 Master. Unlike the mobile application, there is no comparison of the absolute levels of two measuring points, but rather a relative change in the level at a measuring point means that a new leak can be very quickly identified.