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If the cavity is the problem and you only need a unidirectional valve, look at a segment type valve, AKA C-Ball. Just a thought.

Good luck on this one! I cannot provide you with any experience but I would comment that slurry service and valves with a cavity are not a good mix. The cavity will fill with the slurry particles and, in the case of ball valves, the torque will just climb as the particles compact. You COULD have...

Lip seals are very finicky and have all sorts of issues, often associated with the assembly process and good design (or rather lack of). A bit more information would assist: lip seal material; drawing of arrangement; photo of the failure. The first thing I would look at is the surface finish on...

Have you looked at thread 292-471432?

IMO an API 6D compliant valve will have a face to face per API 6D. The exception would be where there is no prescribed face to face dimension for that size/class. In that instance it is up to negotiation between manufacturer and end user. It does occasionally occur that a valve was made when...

Would Table 1 in API 6D not be relevant? 4.4.2 Full-opening valves shall be unobstructed in the fully open position and have an internal minimum circular opening etc etc. I do not believe that B16.34 goes into that area itself.

My stock reply to: How much torque to apply to gland packing?" is: "Until it stops leaking!" Not a particularly useful response, I'll grant, but the best one I can come up with. There are SOOOOO many variables with gland packing, not least: the size and number of the gland bolts, the type of...

Good luck on that one! A dry, abrasive powder would have to be one of the most difficult services for a valve of any description. Certainly avoid any with a cavity where product can become trapped and compacted. My initial thoughts were for a pinch valve, but with the frequency of operation I...

I do not understand the comment "expiry of a Fire Test cert". Assuming we are talking API 607, the test is a type test and is current for the design whilst the date of manufacture was when that standard was current, and, of course, there is a period of grace between the new standard coming into...

I suggest that the reason I would recommend testing a valve that has been in store for a period of time is that (often) valves are not stored particularly well and it is much better to find out that the valve is not working as it should BEFORE it is installed into line and NOT afterwards! The...

For flow capacity, read Cv of the valve.

I would tend to agree with BCD, the material selection should be suitable for the application unless there is some peculiar additive in the fuel. One of the causes for increasing operational torque in trunnion mounted ball valves is the acculuation of foreign matter betweent the back of the seat...

If you can give some more details it would assist: Size? Class? Floating/trunnion? I assume it is just under natural head pressure from your description. How much head? Did you do any examination of the previous valves removed from service? Did you notice swollen eastomers/seals that lead you to...

I would concur with bcd, this is an upstream seat. As the ball moves from the closed to open position, this part of the seat beconmes unsupported by the ball and if pressure gets behind the seat it can push this part of the seat out. The small grooves (notches) that you can see in the...

If you are considering triple offset butterfly then there is a preferred flow direction and that is for the flow to assist in closing the valve. These valves are torque seated and therefore have prescribed limits for the amount of torque that the shaft should be subjected to to limit the seat...

IMO I would say: No. The valve is not the same basic design; I would consider the fact that the body shell is joined differently to disqualify based on this clause. In my experience, the way the body expands and contracts with heating and subsequent cooling affects the performance of the valve...

Hi Tory You really have to go back to the respective manufacturers for an answer on this one. Fire safe sealing is achieved in a variety of ways, one of which is for the seals to 'burn out' and allow components to move and create a 'metal to metal' seal and NOT necessarily rely on, say, a...

I'll just add my two pence worth. I do not have the experience with using but making valves. If you are looking at 1 & 2" valves, I would suggest that you are looking at 3 piece, bolted construction? These are generally rated anywhere from 60 to 138 bar, so the pressures in a vacuum system are...

UAEPiping, You fail to mention the specification to which you are testing. API 607, size 8" (DN200) covers all sizes above. API 6FA a 12" API 6D valve covers 24". Does the vendor not have existing fire safe certs on these size valves? If it is just your configuration that needs to be covered...

Sorry, should have read the question more slowly! However provided that the welding is performed in accordance with ASME IX &c &c &c then the reality is that there is no difference between a flange welded on to pipe or a valve.