Pneumatic sensor help!

Mr. Tezza

Hey everyone!

So I'm trying to design a pneumatically operated system and I want to add a sensor to the system for a bit of safety but I'm a bit lost, I'm pretty sure it a proximity sensor that I'm looking for but I don't know what one to go for (probably going to get it from rs-online.ie).

So to give you an idea of the pneumatic system its basically a 5/2 switch connected to a single-acting pneumatic cylinder. At the moment when you press the button the cylinder goes forward, very simple.

I want to introduce a sensor into this circuit so that unless the sensor is closed when the button is pressed nothing happens.

Can this be done or do I need some sort of PLC for this to work? If I change the button for an electro-pneumatic one will that do anything?

TIA

Hijpo

Do you really need a sensor? What scenario are you looking to protect against?

If its for making sure the operators fingers are not in there you could use two push buttons so the cylinder only fires once both buttons are pressed.

Mr. Tezza

https://www.boards.ie/discussion/comment/119313015#Comment_119313015

I the introduction of a second push button is not what I want to do, it wouldn't work.

Hijpo

Okay so what safety scenario are you trying to overcome?

Is it going on a guard door? Is it going on the cylinder? Is it to make sure a part is in position before firing the cylinder??

Need more info regarding it's application.

PM if you want.

Mr. Tezza

The system is a pneumatically operated can crusher.

The idea is to add the sensor to the door so that the cylinder will only go forward when the door is closed, thats where the sensor comes in, adding a 2nd button would have made the system bulky and I want it to be somewhat portable.

I made a simpler version before without the sensor and no door. I'm in the prtogress of drawing up the system using Fusion 360, the goal is the 3D print as Much as possible using my 3D printer.

Hijpo

I'll send you a PM

The Continental Op

Whats wrong with the traditional chepo cheap microswitch tucked away so you can't manually press it with the door open?

kirving

If it was me, I'd be going for a normally open microswitch (so a broken wire would be failsafe), two push buttons (as you never know who might end up using it).

How do you intend to control the solenoid valve?

The Continental Op

If you want super safe also add a pneumatic valve that purges the system as the door is open. Then there is no air pressure and can't be any until the door is closed.

Mr. Tezza

https://www.boards.ie/discussion/comment/119328023#Comment_119328023

I actually like the idea of that, I can use the purged air to blow the crushed can away into a bin or something!