Spray Bar Hydraulic Fold Cylinder

Function

Each cylinder must carry the static and dynamic load of the wing — typically 60–150 kg (132–330 lb) per wing depending on bar material and width — smoothly through the fold arc without shock loading the pivot frame or nozzle headers. Controlled speed, governed by hydraulic flow restrictors in the circuit, prevents wing bounce on uneven ground and protects nozzles from impact damage. End-of-stroke cushioning reduces shock loads at both the retracted and extended positions, extending pivot-pin and spray bar frame service life.

Construction & quality

Cylinder barrel: cold-drawn seamless steel tube, hard-chrome bored and honed to Ra 0.4 µm. Piston rod: 45–50 mm diameter (1.77–2.0 in), 45CrMo4 steel, hard-chrome plated to a minimum 25 µm depth, ground and polished to Ra 0.2 µm. Seals: polyurethane wiper ring, NBR O-ring piston seal and PTFE guide ring — all rated to 180 °C (356 °F) to withstand radiant heat from the adjacent insulated tank. End caps: welded or threaded steel, SAE O-ring face seal ports. Mounting: clevis ends with DIN ISO 12240-1 GX-grade spherical plain bearings and grease nipples.

When to replace

• Wing folds or unfolds sluggishly, or stops mid-travel under normal hydraulic pressure
• Visible rod seal weep — oil film or drip tracks on the chrome rod surface
• Bar wing drifts or sags when the fold cylinder is nominally locked in deploy position
• Scored or pitted chrome rod surface visible on inspection during wash-down
• Excessive hydraulic pressure demand on the fold circuit compared to the other wing