Recent content by fpnut

How common/safe is it to braze a threaded joint? Not looking to do it, just curious since I came across a really old piping manifold (30+ years old) that was still in use. Seemed to me like an threaded valve brazed onto a block. I'm just wondering how common it is, or any pros and cons of doing...

I ended up making a silicone gasket cut out of sheets. Works fine for now while a redesign is being worked on. Any recommended books on designing plastic parts?

I'll look into it, thanks.

Well the diffuser manufacturer (and most of them) offers it only from HDPE/UMWHDPE, so I don't have much of a choice here.

The difference is about 35-130 x 10^-6/K (diffuser is HDPE, the inner part is PC). In regards to creep - the parts will be interference fit, so probably yes.

I don't have experience designing plastic parts that mate together, so I'd appreciate some pointers. Basically I ordered plastic gas diffuser that will be pressed to fit, and I have made the inner diameter of the filter too loose, causing gas to leak from the mating surfaces. Both diameters I...

1503-44, I initially thought about it, but decided against it for privacy reasons. Littleinch, He did do a table for different pressures, but only for a few pressures, since that's all we are dealing with at the moment. I plan to gather data using existing field installations, perhaps that...

Thanks all for the discussion. Well my application is relatively simple and not complex/critical like those in O&G requirements. And it's more of scratching a personal itch rather than doing it for production work. I recently started work in a company mainly doing gas distribution...

Hi Goutam, thanks, I'll have a look at Crane. Hi Katmar, thanks, I'll do some verification based on your links.

Hi All, I've just made a simple spreadsheet for estimating pipe diameters. Since my application is for gas, lower pressures (<30 bar), short lengths of pipe (<30 metres), relatively low pressure drop, I've opted for a simple Darcy-weisbach equation, coupled with Swamee-Jain friction factor...

Hi All, I recently came across this problem, though I am not responsible for it, but found it interesting nonetheless. A chemical plant recently replaced a valve for a cryogenic liquid (ethylene). Previously they had been using a ball valve, but for some reason they chose to use a globe valve...

I've scoured over the internet looking for information on this, and there seems to be little to no information on the track record of such usage. I did find one company with a picture of what looks like an electric actuator on a copper piping line that is implied to be oxygen. The company didn't...

Hi MR, Thanks for the detailed explanation. Looking at those documents and the risks involved, I think I'll have to change the design to avoid using electric actuators. I am aware of those documents, but have not consulted them. In regards to the oil/grease, assuming pneumatic actuation is...

Hi, I am in the process of designing some pipelines for gaseous oxygen, and is in need of an actuated shut off ball valve. Typically I would use a pneumatic actuator for this service. However, for this application there are no compressed air or nitrogen available for actuating the ball valve...

It's the yield strength, which will be the reference limit for stress calculations.