Construction

Reed Sensor Applications in Construction and Security

A reed sensor is the best choice when it comes to construction and security, due to the fact that they can work reliably in dirty environments amidst dust, grease, and oil. Unlike optic sensors, reed sensors used in dirty greasy environments are maintenance free and do not need any cleaning. A few applications are listed below. We have also suggested few of our products for use in each application, but this does not mean that the other products in the same product category will be unsuitable.

• Deep bore liquid detection
• Door and window security
• Floor detection in elevators and lifts
• End position sensing in hoists
• Emergency lamp holders
• Explosion proofing in mines
• Monitoring settlement in the soil and rock
• Blowers and vacuum ducts
• Adjustable chairs and beds
• Tamper proofing meters

Deep bore liquid detection probes

Reed switch based float switches are fitted with a perforated sheet around the whole float assembly. This assembly can be used as a depth probe and lowered into narrow bores with the help of the lead wire. The perforated sheet...

Door and window Security

Magnets can be mounted on doors and windows, and reed sensors, on the fixed frames. As long as the doors or windows remain closed, the contact is not broken. Normally open (NO), or normally closed (NC) reed sensors can be used depending on the circuit logics. Special reed sensors which contain highly accurate magnets can even sense metal doors using the principal of field shunting. Suitable products: MS-324 and MS-328 flat pack sensors

Floor detection in Elevators and Lifts

Latching reed sensors can be mounted on every floor, and a magnet on the elevator or lift will actuate them as floors change. Latching reed sensors can be mounted in two ways with respect to the pole of the magnet. Reed sensors on floors above can be latched and floors below can be unlatched, or vice versa. The latched and unlatched condition of the sensors can be compared to electronic flip flops with built in driver circuits, and have the added advantage of switching higher loads. Suitable products: R2E latching reed sensors, HW-5052 reed switches, and MS-228 threaded sensors

End position sensing in hoists and fork lifts

Hoists and fork lifts use hydraulics to move cylinders and pistons to life heavy weights. Reed sensors can be used on these pistons and cylinders to sense end positions and intermediary positions and the signals can be used by the proportional pressure valves for control of oil pressure to the cylinders and pistons. Suitable products: MS-216-L cylindrical sensors, MS-228 threaded sensors, and MS-328 flat pack sensors

Emergency lamp holders

When emergency lamps are taken off their holders, a buzzer should sound. The lamp itself can be built with a small magnet, and a normally closed reed sensor can be mounted on the holder. As long as the lamp is in its holder, the buzzer circuit remains open. Taking the lamp off the holder, closes the reed sensor and triggers the buzzer circuit. Suitable products: R2B normally closed reed sensors, R2 normally open reed sensors, and MS-10x miniature PCB mountable reed sensors

Power switches for explosive areas

Reed switches, being hermetically sealed and unaffected by the atmosphere and surroundings, can be used with sliding magnets to work as on / off switches in explosive areas, for example, in mines where arcing could cause an explosion. Reed switch based reed relays are also safe devices to use in explosive areas for switching higher loads. Suitable products: MS-10x PCB mountable reed sensors, and goal post formed SM-1322 and HB-2232 reed switches

Magnet Extensometers

Reed switches are used in magnet extensometer probes to monitor settlement and heave in construction sites, dams, excavations, mines and tunnels. Access pipes are inserted into the earth, and magnets are provided at every joint and coupling. The reed switch probe, coupled to a measuring tape is inserted from above. Each time the probe comes near one of the magnets, an indication is given and the depth can be read off the tape. Suitable products: HB-2232 and LV-1925 reed switches with cropped leads, encapsulated in probes

Blower and Vacuum duct efficiency

In blowers and vacuum ducts, a vane with a tiny light magnet is fitted across the flow of air, inside the duct. A reed sensor is mounted outside the duct. Nominal flow of air lifts the vane and keeps it near the reed sensor. If the rate of blowing or sucking decreases due to dust collection in the filters, the reed sensor does not get actuated. This signal is used to trigger a "filter change" LED. Suitable products: MM-1018 and UM-0018 ultra-miniature reed switches with cropped leads, in vane sensors

Adjustable chairs and beds

Chairs and beds with electronic controls for adjusting tilting and height use reed sensors to sense intermediary and end positions. A magnet is mounted on the moving part with the reed sensor mounted on the stationary part. These sensing voltages are very low and therefore, there is no risk of electric shocks. Suitable products: MS-328 flat pack sensors and MS-216-L cylindrical sensors

Tamper proof meters

Electricity meters, water meters, and gas meters use a reed sensor to prevent unauthorized opening of the panel covers. The reed sensor is mounted inside the housing with a magnet on the cover. If the meter cover is opened, the reed switch opens and shuts off the meter. Only a service person with an adapter which plugs into the system can reset the meter with an external command. Suitable products: MS-324 miniature flat pack sensors, and MS-214 cylindrical sensors