floating ball valve 3

[engahmedbahgat]

good afternoon, I have a question about floating ball valve, when this valve is closed, the pipeline upstream pressure pushes the ball against downstream seat ring to attain tight seal, at this case I imagine that the ball as pushed toward downstream seat, it pushes away from upstream seat, so the valve cavity will be connected to pipe upstream pressure and if I trying to open body bleed to depressurize the cavity, it won't be depressurized, it that true or not? and what will be the case in open positions? thank you in advance

 

[SkyeTan]

Perhaps this link would be more appropriate.

Source:

https://www.youtube.com/watch?v=hSIqpzr6nu0

 

[LittleInch]

Skyetan,

No it doesn't count. If you look carefully at the first diagram, you can see at the bottom of the ball a little pin. This is the trunnion which olds the ball in place while the seats move to adjust it. The video makes it look like the ball is not perfectly round and that the seats move as it is opened and closed. this might be artistic licence (I like the way the valve contents just drain onto the ground.....?), but does indicate that it is the seats which move, not the ball.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[zdas04]

What LittleInch said. It looks like a pretty cool version of the trunion ball valve (and I like the video), but nothing to do with floating ball.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

 

[SkyeTan]

LittleInch,

Oh I see. The field I'm in (HVAC) did not classify ball valves so strictly so the exposure to different types of almost similar looking ball valve is quite minimal to me. I should also explain that I am just a fresh grad in the business for almost half a year.

Thanks for the info.

 

[eliam]

floating ball valves are not suitable for body bleeding. is dangerous, you have the upstream pressure inside of the cavity.