Most valve manufacturers catalogs carry P-T ratings in the appendix. For example you can go on-line to the VELAN site at www.velan.com and find the ratings for some materials. Go to PRODUCTS, CATALOGS, CAST STEEL VALVES, page 34-35, where you will find ratings per ASME B16.34.
"ASA" (American...
API 602 covers small steel socket welding end valves. In general, there are no end-to-end dimensions provided, however, there is a range given for the "extended body" styles.
Carletes
You would use the relevant Code and other references to determine the suitability of the trim materials just as you would for the body material keeping one thing in mind: the trim materials have to be equal or better than the body material because they are "working" parts...
PTFE (or any other "soft" material) and sand don't go together. Metal seated valves are recommended. I dont know what your application is, but if you are looking for zero or low leakage, you might try lubricated plug valves or the triple eccentric HPBV.
Forgings are better than castings as described by "bljnv" above. API 602 for small compact gate valves allows both. Lately, I have also noticed that many ball valve and needle valve manufacturers are offering cast bodies - especially in stainless steel. I believe it is a question of...
TBP makes a good point. Butterfly valves will make a more cost-effective solution even if you go with the top-of-the-line triple eccentric metal-seated butterfly valve.
However, if you still wish to pursue the ball valve, I would suggest the following spec assuming that the water is treated...
Carletes
I think it's a question of the risk/reward ratio. Why spend more money on water service valves? The worst that can happen is that the water will leak - more a nuisance than anything else. If you pick a good quality manufacturer, then his quality system should be adequate. Also, your...
The valve manufacturer is the best one to ask.
In general, I can think of two concerns during welding and PWHT: (1) Weld splatter could cause damage. This is to be avoided by putting the valve in the position where the least damage can occur e.g. if it is a ball valve, keep it in the open...
I would appreciate receiving the names of companies that are capable of undertaking market research for valve manufacturing in the Middle East.
Thanks.
These are some common standards:
Ductile iron flanged valves - ASME B16.42
Cast Iron flanged gate valves - ASME B16.1 & MSS-SP-70
Wafer, Lug, Flanged Buterfly valves - API 609
Butterfly valves don't always follow the standards. Suggest you check with the manufacturer as recommended by...
As far as I can tell from ASTM A194, the chemical compositions are the same but the manufacturing process and heat treatment is different. This results in hardness range requirements of Brinell Hardness 126 - 300 for 8M and 126 - 192 for 8MA.
