EMS Blog

Why EMS Monitors Do Not Require Fail Safe Shutters

In reality, failsafe shutters to fail and don not afford the protection that is claimed by the manufacturer.  Because they are in a dirty air stream, in a short period of time dirt and corrosion causes them to get stuck.  Because of these problems, some of our competitors actually require the user to check them routinely.  This requires extra time for the user as well as defeating the purpose of the shutters in the first place.

Most failsafe shutters do not have gas tight seals, so even when they are closed gas gets through and damages the sensors.  This is because the sensors are designed without protection and they depend on the shutters.

Some designs utilize the air flow rather than solenoids to close the flapper valve, which causes them to get stuck fully or halfway open.  This will cause the shutter to dip into the beam causing high opacity readings.  Basically, they cause more problems then they solve.

What does EMS Do In Place of Failsafe Shutters?

EMS has designed the sensors with protective, gas tight glass windows.  If the air purge should fail, there is no damage to the sensor optics or electronics because of the protective window.  A simple alarm condition in the controller alerts the operator of the flow failure because left unresolved dirt will collect on the windows (dirt is also alarmed).

Our monitors have been field proven for over 20 years with over one thousand applications without incident.  We are so confident in our protection, that we will extend our warranty for damage to our sensors caused by blower failure.  The extension is 3 years longer than the competitors written warranty against sensor damage if their blower or failsafe shutter should fail.  Historically our competitors have refused to put such guarantees in writing even with so called “failsafe shutters”.

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