vibrating screen protection ideas

[lespoils]

Hi all,

Here is my situation. At the plant i work at there is a vibrating screen to seperate the fines out of woodchip biomass. Our problem is that the arms suspending the screen sometimes break and the screen falls down on the structure.

Currently, there is nothing telling the PLC that the screen has fallen and the screen is located in a remote place, so the vibrating motors sometimes keep running for an hour or two. Damaging the screen and structure.

I am thinking of adding 2 pull cords forming an "X" beneath the screen, so that when if falls off, the plc will at least be able to stop the motors. But to my knowledge, safety pull cord dont let go of the cable, so i started looking for something like a "pull pin switch" and haven't found anything that seemed made for industrial settings.

found this which seemed interesting : https://leemangeophysical.com/product/pull-pin-switch/

So basically, i'm asking if anybody can propose any other product that could help the PLC detect that screen has fallen down.

Hope i am being clear and precise enough in my explaining.

Thanks
Lespoils

 

[waross]

This Ain't my first Rodeo!
This is an also an issue in the otherwise unrelated arena of rodeo timed events.
When an animal is to be released from the chute in a timed event, there is a barrier that may be released or broken.
The purpose is to give the animal a head start over the cowboy.
The animal has a rope about 10 feet long that pulls a pin and releases the barrier.
If the cowboy starts before the pin is pulled he will "Break the barrier".
The barrier rope has a joint formed by a piece of string joining two rings.
If the cowboy hits the barrier before the pin is pulled, the string breaks and the cowboy is assessed a time penalty.
So, in your case, use a weak link that is strong enough to activate the safety switch but not strong enough to support the screen.

 

[IRstuff]

That's certainly one way. There are a number of non-mechanical sensors, photoelectric, Hall, capacitive, etc. They have the benefit of not necessarily being bothered by dust and dirt