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Level & Flow
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Proximity Switches
MLS-3EX
The MLS-3EX is a magnetically activated single pole double throw switch. When the MLS-3EX is mounted on an external chamber (such as the VISI 1310 or 1322V/VA sight tube) that has a magnetic indicator, it can sense high or low levels within a vessel.
The unique magnetic coupling action eliminates the need for such things as seals, diaphragms, springs, or torque tubes because there is no physical contact with the process. Magnetic coupling eliminates process connections to the switch and ensures complete isolation from the process. No valves are required to block off the switch from the process to perform any maintenance or operational checks.
The MLS-3EX consists of a Form C reed switch and a bias magnet. The reed switch uses precious metal contacts in an inert gas atmosphere sealed by a glass-to-metal bond. The bias magnet is what allows the switch to maintain contact after the activation magnetic field is removed. A Magnetic float passing by the MLS-3EX in either the upward or downward direction will cause the reed switch to change states. After the float has passed, the reed switch will maintain its state until the float reverses direction and passes the switch going in the opposite direction. The action is break before make.
A pneumatic version is also available.
Features:
- Unique concept of magnetic coupling eliminates direct contact with the process
- No process piping or valves required
- Easy mounting and adjustment: only a small screwdriver required
- Trip point infinitely adjustable without changing process piping
- SPDT switch (Normally open or closed contacts)
- Not affected by vibration
- Compact design
Applications:
The MLS-3EX will provide either a normally open or closed dry contact that can be used to activate external devices such as alarms or solenoids. The capacity of the switch allows for a wide range of devices to be switched, as long as the stated limits are not exceeded. Since the MLS-3EX is magnetically activated, it is suited for any application where it is necessary to sense the passing of a magnet or magnetic field near to it. However, its main application is to sense the passing of a magnetic float in a chamber attached to a vessel containing a fluid. This will provide for the detection of a start/stop trip point of either a total or interface level in any vessel. These trip points can be used for alarms or to activate a pump motor starter relay.