Oleodinamica Marchesini VN631 npt in-line check valve

Oleodinamica Marchesini VN631 is the 1 1/4" NPT execution of the VU family. Its complete article code and NPT size are explicitly listed in the supplier catalogue. The original manufacturer sheet specifies NPT as an option with the VN code prefix; this actual code was observed as an offer, not generated from that ordering rule.

The original VU 1 1/4 performance row gives maximum flow 250 l/min and maximum component pressure 300 bar. Connect V to supply and C to the actuator or function. Flow is free from V to C and blocked in the reverse direction.

The exact supplier row and the original size row give the standard opening reference 0.7 / 1 bar. This is retained as a text reference, not converted to one exact cracking-pressure filter. No 1, 3, 5 or 8 bar calibrated spring is inferred for this bare NPT code.

The VU family uses hardened and ground steel internals in a zinc-plated steel body with guided-poppet sealing. BSP-thread lengths, masses and envelopes printed in the separate dimensional table are not assigned as exact NPT dimensions. No seal compound is invented where the original VU sheet does not state it.

The local technical PDF retains the complete relevant original manufacturer spread, including the exact size or kit row, option legend, hydraulic circuit and installation drawing. Adjacent executions apply only to their named rows.