Reed switches in Magnet Extensometers

Whenever there is a deep excavation that is done prior to construction, the excavation has to be monitored prior to starting construction. This is a safety precaution. The depth at which any settlement may occur needs to be noted and this is where magnetic extensometers help.

Reed Switches are used in Magnet Extensometer probes to monitor settlement and heave in foundations, excavations, dams, embankments, construction sites, mines and tunnels. The data collected by an Extensometer helps indicate the depths at which settlement are present. First, access pipes are inserted into the earth, and magnets are provided at every joint and coupling, at known, fixed distances. These joints are grouted to the soil and move whenever settlement occurs. The reed switch probe, coupled to a measuring tape is inserted from above. Each time the probe comes near one of the magnets at the junctions of the pipes, it triggers the reed switch and an indication is given. The depth can be read off the tape.

Application Classification

Applications are classified as Position Sensing, Pulse Counting, Electromagnetic or Relay, Temperature Sensing or Magnet Biasing types. This application is classified as follows and the link gives more information on best practices to help select the most suitable AT band and matching magnet.

Position sensing Type

Position Sensing type application When an application requires the end position of a movement sensed, or the sensing of a part when it Continue reading -> Nov 7, 2020

Recommended Products

The Reed Switches and Sensors used in such applications need to be robust, durable and efficient in meeting a high life expectancy. Our engineers work hard in life testing our products under various conditions, and our intention is to ensure end product durability and life. Although we wouldn’t want to restrict any of our products for use in only certain applications, the recommended products for use in this application are listed below.

MS-228, M8 Threaded Cylindrical Sensor

MS-228 M8 Threaded Sensor Drawing starFeatures30W Contact Rating. Normally Open contact. Three sensitivity bands. Sputtered Ruthenium Continue reading -> Nov 20, 2020

HW-5052 Reed Switch for High Wattages

This HW-5052 High Wattage Reed Switch is physically robust and can switch up to 120W. The two types of contact ratings available cover a Continue reading -> Dec 3, 2020