Function D20 - 1:2 ratio
The standard directional cover (model code letter N), contains a pilot pressure passage with an orifice to control the poppet’s opening and closing rate. When used with insert model D15 (1:1.5 area ratio poppet), or model D20 (1:2 area ratio poppet), the combined cover and insert, becomes a check valve. Port X in the cover is connected to port B in the insert. This allows free flow from insert port A to port B while blocking flow from B to A.
Single or dual solenoid pilots are applicable, depending on circuit requirements. The spool center condition of the solenoid pilots also depends on the circuit function desired. Ports Z1 and Z2 are for remote control of additional cartridges. That is, for D3 covers, Z1 is connected to pilot port A. The X port is the pilot pressure port. The Y port should always go directly to the reservoir. The insert used can be either the model D15 (1:1.5 area ratio poppet), or model D20 (1:2 area ratio poppet).
The shuttle function in combination with a solenoid operated pilot valve is available in cartridge sizes 16 through 63. In each cartridge size, the pilot valve is the DG4V-3 that mounts to the ISO 4401, size 03 (ANSI/B93.7M-D03) interface. There are two functional cover types, W13 and W33, that are applied with a model DG4V-3 pilot valve. The insert used can be either the model D15 (1:1.5 area ratio poppet), or model D20 (1:2 area ratio poppet).