Which ball valve to use when high diff. pressure after closing? 1

[UMIST]

1/2" Valve on the chemical injection skid used for scale inhibitor shutdown.
Norsok VDS: BL7941
Material, trim: AISI 316
Material, Seat: PTFE based (teflon)

Normal operating pressure is 4 barg, but the valve could see a diff pressure of 226 barg after closing.

The suppliers I've been in contact with so far say they can't deliver because of the high diff pressure.

Does anyone know of any valve types that can handle the high dp requirement?

 

[bcd]

UMIST,

Ball valve is a good choice, except PTFE seat is not strong enough to withstand such high DP. Same valve with Nylon, Delrin, PEEK, or other strong plastic seat will do the job very well. Small ball valves with such seats can handle up to 310 bar or more. Contact a respected ball valve supplier and they should have no problem getting you this type of valve.

 

[valvetech]

Depending on the actual flow rate of the system, and the required Cv to pass the flow, you might be able to go with any number of some of the globe style fractioanl flow valves on the market. Some can handle Delta p's as high as 344 bar (5000 psig).

Again this if dependent on the flow parameters.

Another solution might be to reduce the amount of pressure that the valve will see when it closed by installing a recurculating line, or by-pass if the system can tolerate it. This will acomplish two things: 1) allow you use a simple valve in the current installation. 2) ensure that the valve will have a longer life by not having to work so hard to cover both the high and low pressurers in this application.

 

[chuchcatlanta]

for extreem pressures you might consider a VOGT gate valve--they have some rated up to 6000psi ---commonly used in NUKE plants