Description
When pressure at V2 rises above the check spring bias pressure, the check seat is pushed open and upstream flow is allowed from V2 to C2. Reverse flow (C2 - V2) is locked, in a leak free mode, by valve (1). Downstream flow (C2 - V2) is possible when Pil pressure rises above the bias pressure of the valve (1) spring. The back-pressure at V2 is directly additive to the spring and tends to close the control plunger: it restricts the flow area and it increases the pressure drop through valve (1). If Pil pressure is limited and kept constant, also back-pressure at V2 will remain constant, and downstream flow (C2 - V2) will stay constant, controlled only by the Main Control Valve opening (V2 to T), independently from the load (C2 pressure). The result is easier and better control during lowering. The leak free pressure relief valve (2) senses C2 pressure and opens under overload or shock conditions.
Note: port identified with M are not protected with calibrated orifice but in direct connection with pressure channels.
Note: aluminium bodies are often strong enough for operating pressures
exceeding 210 bar (3000 psi), depending from the fatigue life expected in the
specific application. If in doubt, consult our Service Network.
