thread378-478159
This seems to be a recurring thread topic.
Just wondering where people go for reference information?
Do people stick to the tried and tested Pearson or do people look at some of the newer books which have been coming out recently?
Pros the vague content of Zappe etc. enough...
Working for a manufacturer who makes Bronze valves there are 4-5 manufacturers globally who produce products worthy buying.
Depending on the application Bronze can be superior to Stainless, I’ve seen a stainless valve fail in 5 years whereas a Bronze equivalent has been shown to last 30years+...
This is a bit mad, you’ve got a potential leak path behind your screwed insert; not that it’s a big issue on a check valve with the leakage rates on offer. There needs to be a way to retain that ring by mechanical means too to stop is unscrewing in service
Most wouldn’t do this but offer a...
Erm, what concentration is your Sodium Hypochlorite? Usually when there is any of this you’d used a Titanium valve.
The actuator output is also set to the MAST rather than a multiple of your BTO I.e. BTO x 2 would be 17000Nm. So looks like you’ve damage the stem or drivetrain or related...
Just because the company is in the Uk doesn’t preclude specs which aren’t BS or BS EN. The only specs which actually cover this valve type are API specs.
You’d be better off requiring coverage from on of these specifications.
None, is no need to hard face it; we have this debate with lists of these products which go through expert contractors who seem to think all gate valves need hardfacing.
If you want a better performance use a Monel Wedge
I’d go with a dual plate check valve, small size good cost, spring loaded so a good response.
With that much water head you could be going for water hammer depending on the exact details of the setup you’ve got there. Plus this is what they were design for…
BCD is definitely correct there then.
Didn’t you request an IOM from the manufacturer? Wondering what manufacturer it comes from…
A typical recommendation for some systems is if you want a FF wafer dual-plate check to take a lugged valve manufactured from bar so the gasket is compressed between...
Btrueblood, nicely noted everything which is not recommended practice.
If you were to read ASME PCC-1 it would show you for joint integrity the gasket should be suitable for the flanges it is used on; no lubricants or sealant should be applied to the gasket faces or the flange faces...
Considering you have a PN16 raised face flange you won’t be able to use a full face gasket as you won’t get compression past the raised face portion.
It would be sensible to specify the material you want to use I.e. EPDM, the shore hardness required and the raised face and bore dimensions to a...
That’s true, but the location of where you put the smallest flow area in the valve will have a massive affect on the performance and service life of the installed valve.
If it is at the seat and you design the valve properly and select the right materials the valve could work for 30+ years, if...
Assuming this is a standard isolation valve?
The flow area wants to never drop below the pipeline area for the valve, except across the seat diameter which code rules allow down to 90%.
This way you ensure any fluid phenomena in the valve is across a replaceable component.
Chasing cost for the...
Hopefully the valve is to API 609 and not a commodity valve as it is a triple-offset.
API 609 requires the bolts to be the relevant flange bolting and threaded to a minimum depth, you should be able to use standard flange bolting to complete the joint even with these holes being threaded/studded.
It will depend on what valve you are trying to design as to what method you should use.
It also depends how critical any leak from your flanges joint is as to the method used.
I’d imagine you have a MAST figure for the gate valve if yourselves designed it or it was supplied from a reputable manufacturer?
By the looks of your figures you MAST will be high enough to handle the load. If in doubt you can calculate the shear stress in the stem which is engaged when the...
I have a recollection that the responsibility for the PTFE seats not to melt when the valve is welded into the line lies with the manufacturer.
From memory Velan manufacture this valve with a cryogenic stem extension and access hatch, might be worth a look?
Just workout the open area of the disc against the seat then plug those figures into the calculations from Crane?? The area will vary depending on what type of gate valve you’re thinking of, I.e. a circle closing over a circular area will create a crescent shaped area.
Just need to be a bit...
