Float Switches replacement 1

[RSTEng1]

Hi,
I am looking for the option to replace 'classic' float switches used in sanitary pumping applications, with something more reliable with less maintenance.
Maybe some type of capacitive proximity switches?
We need four switches for LoLo, Lo, Hi, and HiHi alarm, connected to the PLC digital input card.
At the same time LoLo will be implemented into the hardwired circuitry (pump protection if analog level stop failed) as well.
HiHi will also go to the hardwired logic to provide backup pump start signal created by analog level indication and start setpoint.
Is there anyone with some experience in this matter?
Please suggest.
Best,
Filip

 

[TugboatEng]

Vibrating fork type switches are the most reliable. If you can afford them, start there. Oriented correctly, they can self clean. Most can also provide a heartbeat output to alert of a switch failure. Start here:

https://www.emerson.com/en-us/catalog/rosemount-sku-2120-switch---vibrating-fork

You already have an analog sensor. The analog sensor should provide your high and low alarms (pump failure). The additional level switches are for the lolo and hihi and indicate a failure of the analog sensors.

Also. Consider using radar sensors for level as they can see through foam that may occur on the surface of the fluid. Pneumatic bubbler sensors work well provided you have a constant supply of air.

 

[RSTEng1]

Hi TugboatEng,
Thank you for your prompt post.
Although Vibration Fork is excellent method, I am afraid is not suitable for wet well application.
Best,
Filip

 

[horacio Torres]

Level Magnetic or ultrasonic level switches are reliable instrument devices. I set you a rosemont and  Ameteck web page.

https://www.drexelbrook.com/products/point-level-measurement/ultrasonic-level-measurement

emerson.com/en-us/catalog/automation-solutions/measurement-instrumentation/level/magtech-ltm-level-transmi

horacio

 

[bimr]

The Ametek 675 Submersible Level Sensor was specifically designed to perform in sewer lift stations.

Link

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