A P4 valve by MFV (image courtesy of MFV)
The valves are the first of their kind to feature the Hardide-T coating, which can be applied to choke valve stems so they can withstand temperatures up to 200°C and pressures of 1370 bars.
Canada-headquartered MFV found that alternative hard coatings previously applied to the stem assembly were not rated to sufficiently high temperatures. The challenge was to have a durable coating with a completely smooth finish to form a tight metal to metal seal.
The two companies worked together to engineer a solution and develop a manufacturing process plan: Hardide Coatings and MFV oversaw the manufacturing process and fine-tuned it to ensure specific surface finish and geometrical tolerance requirements were met.
The coating has been applied to MFV’s P4-15K choke valve, which is rated from -28°C to 200C and 1000 bars, and the P4-20K choke valve, which is rated to the same temperatures but a greater pressure of 1370 bars.
They are typically installed on subsea production trees and are used for single/multi-phase production or water/chemical/gas injection. There is also an application for use on a capping stack, designed to be deployed in the event of a blow-out situation.