Hi Djaz
My selection for this application is usually a monoflange DBB valve with 2 metal seated ball valves in the main bore, and a needle valve for bleeding. I am also adding a instrument block and bleed manifold with needle valves to the transmitter pressure connection. This make it possible...
No Valving, I am not saying there is no wear between disc and sealing. Unlike a single eccentric, a double eccentric valve, will have no swiping contact between the disc and the sealing. This fact will reduce the wear, and prolong the lifetime of your valve. if your service is clean like...
A single offset valve will have the shaft placed behind the centerline of the sealing area. In addition on a double eccentric, the shaft is placed offset to one side of the valve centerline. Benefits of an double eccentric valve versus a single eccentric is that the seat and the disk will not...
My opinion is that you should not open an actuator of this type unless it is necessary. There is a greater chance of damaging anything than prolong the life of the actuator.
A visual inspection and functional test shall be a sufficient maintenance. The frequency of maintenance should be driven...
I mostly work with Statoil specs. The requirements for this TCC spec is:
The coating shall be in the range 0.15 to 0.25 mm after grinding and lapping. All coated parts shall have maximum roughness of Ra = 0.15 µm.
The spec is not referring to any quality standard else than for bonding test.
Se...
The acceptance criteria for the leakage test could be stated in the valves design code.
API 6D/ISO 14313 set criteria for acceptable leak rate according to ISO 5208 in the testing chapter.
Leakage for soft seated valves shall according to API 6D not exceed ISO 5208 Rate A
ISO 5208 is harmonized...
My proposal is a trunnion mounted ball valve with metal seats, and an actuator with a "fail safe" mode. Like this: http://www.biffi.it/details.asp?vi=1&liv2=Electric&pos=2&mod=EFS+2000+INTELLIGENT+FAIL-SAFE+ACTUATOR
