Hydraulic Bulkhead Fittings for Panels, Tanks, and Barriers

A hydraulic bulkhead fitting lets a hose, pipe, tube, or instrumentation line pass through a barrier while keeping the connection controlled. The barrier may be a panel, tank wall, steel plate, machine frame, enclosure, truck floor, or other surface that the line has to cross.

The fitting creates a fixed pass-through point. Instead of leaving a hose or tube unsupported at a hole, the bulkhead fitting holds the connection in place and allows the line to continue on the other side.

How the fitting mounts

One end of the bulkhead fitting has an extended threaded section that passes through the barrier. A locknut is installed on the opposite side to secure the fitting. Depending on the design, the fitting may help create an air-tight or water-tight seal between the two sides, or it may simply support the hydraulic line and protect the route.

Once the bulkhead fitting is secured, hoses, tubes, or adapters connect to each side. The result is a continuous flow path through a surface that would otherwise interrupt the line.

Where bulkhead fittings are used

Bulkhead fittings can be used to move fluid into or out of tanks, through panels, through enclosure boxes, through truck floors, or through machinery walls. They may also act as distribution outlets or fixed service points in piping systems.

Common locations include hydraulic panels, valve cabinets, reservoirs, tank walls, brackets, agricultural equipment, construction equipment, mining equipment, oil and gas systems, trucks, and industrial machinery.

The reason for using a bulkhead fitting is usually control. It controls the route, protects the line at the pass-through point, and makes the connection easier to inspect or replace.

Body configurations

Bulkhead fittings are available in straight unions, 45 degree elbows, 90 degree elbows, and tee configurations. The correct shape depends on the route on both sides of the barrier.

A straight bulkhead may be enough when the line continues directly through the panel. An elbow or tee may be needed when space is tight, the hose must turn immediately, or the connection also has to feed another line.

Body style should be selected with the installed route in mind. A fitting with the right thread but the wrong shape can pull a hose into a tight bend or force it against the panel.

Thread and sealing styles

Bulkhead describes the mounting style, not the thread standard. A bulkhead fitting may use NPT, 37 degree JIC flare, O-ring face seal, O-ring boss, DIN, BSP, or other connection styles.

That means the replacement must be identified by both sides and by the mounting section. One side may be JIC, the other may be NPT, ORFS, ORB, BSP, metric, tube, hose-end, or another adapter connection.

The sealing method also matters. A JIC bulkhead fitting seals on a flare. An ORFS bulkhead seals on a face O-ring. An NPT bulkhead uses pipe thread engagement and sealant practice. Similar-looking bodies can fail if the sealing style is wrong.

Materials and applications

Bulkhead fittings are used across many industries, including aerospace, automotive, chemical processing, construction, agriculture, mining, oil and gas, and pulp and paper. They are available in a range of sizes and materials to match the same pressure, corrosion, fluid, and service requirements as other hydraulic fittings.

Before ordering a replacement, record the connection on side A, the connection on side B, the barrier thickness, hole size, locknut details, washer or seal details, body shape, material, and installed orientation. The fitting has to work as both a connection and a mounting part.