Weld-In Bulkhead Coupling

The weld-in bulkhead coupling is a pass-through fitting that is permanently fixed by welding to a bulkhead, tank wall or shell plate. It has a 24° cone on each side; the tubes on both faces of the bulkhead are connected with a nut and ferrule. Unlike a bulkhead coupling with locknut, the penetration is made permanent by welding, both mechanically and in terms of bulkhead tightness.

It is used in shipbuilding on hydraulic lines passing through watertight bulkheads, between the steering gear room and the engine room, at tube outlets on hydraulic tanks and pressure vessels, and at enclosure penetrations on offshore platforms.

• Weld compatibility between the coupling and bulkhead materials must be evaluated; when welding a stainless steel coupling to a carbon steel bulkhead, a suitable filler metal is selected.
• Welding heat must not distort the cone seats; the cone surfaces should be protected during welding and, if necessary, welding paused to let the part cool.
• Bulkhead thickness and hole diameter should be provided before ordering.

Installation note: After welding, remove oxide and burrs from both faces, and make up the tube connections only after the cone seats have been checked.