Safety Interlock for Pressure Vessel

[hanabie]

Hello,

I'm currently looking for an appropriate safety interlock for a small pressure vessel. The lock is to prevent the user from opening the door when the vessel is pressurized.
I'm not using any quick opening design. Do you guys know which safety interlock can be used for small pressure vessel around 6 gallon?
We would like to control the safety interlock too.

Thanks in advance.

Best

 

[gr2vessels]

As the QOC's are proprietary designs, so are the interlocks too. I'm not aware of any design given out for free, but you might be lucky, try the internet. However, you either need to re-invent the 'wheel', then prove it works, copy an existing design and test it to destruction to prove it works or order one from the pro's. Your choice.
Cheers,

 

[EngAddict]

If it isn't quick opening then the seal will likely leak before they get it open. Will a pressure gauge and warning sign on the door cover your liability?

 

[hanabie]

Hello,

@engaddict, Yes we have a switch that on the door and a pressure gauge. When the user does not tighten the door, the program will never start. It will also alert the user.
However, we can't rely on that switch. Some curious users, they will still try to open the door even with "two steps open" (open a small gap and let the steam release before fully open the door).
We do not want to see that happen. I've been searching for off the shelves safety interlocks. It could be solenoid. It would be great.
At this moment, I could not see any safety interlock that will fit to our design mainly due to experience.

My point is trying to prevent the door from fully open during the operation even the user try to do something differently. As soon as the operation is done, the user will be able to open the door whenever they like.

Thanks anyway.

 

[EngAddict]

Ah so it is rather quick opening. What about a standard solenoid locking interlock, like the one in the link below, hooked up to a pressure transducer. You can feed it into the control system or keep it local.

http://www.warnerelectric.com/PDF/P-1201-WE_sensors-pg54-55.pdf

 

[austsa]

Try Smith Flow Control. GD uses SFC interlocks on their QOCs.
I'm aware that you can get a (special order) SFC interlock with pneumatic cylinder (perhaps elec solenoid?) as a secondary lock. This way, the cylinder must be retracted (usually by the control room operator) before vessel operator can use their key to unlock the primary lock and gain access.
Note though that quite a bit of design work is involved to add an interlock to a vessel:
- Interlock is generally bolted to a bracket that is welded to the vessel
- When interlock is operated, a slide bracket (included when you buy the interlock) is released. So, you'll need to do some design work - add components to your door so that door cannot be opened unless slide bracket is released first.