DZ Pilot Operated Pressure Sequence Valve

Pressure sequence valve, pilot operated, type DZ...L5XPressure valves type DZ are pilot operated pressure sequence valves. They are used for pressure dependent sequence switching of a secondary circuit.The pressure sequence valves basically consist of main valve (1) with main spool insert (7) , pilot valve (2) with pressure adjustment element and optional check valve (3).The valve function is dependent on pilot oil drain configuration:Type DZ.. -.-L5X/.....(Control lines 4.1, 12 and 13 open；control lines 4.2, 14 and 15 plugged)The pressure in port A acts on the pilot spool (5) of the pilot valve (2) via the control line (4.1). At the same time it acts on the spring loaded side of the main spool (7) via orifice (6). When the pressure exceeds the setting value of spring (8), the pilot spool (5) is moved against the spring (8). The fluid on the spring loaded side of the main spool (7) flows to port B via orifice (9), control land (10) and control lines (11) and (12). There is now a pressure drop at main spool (7), the connection from port A to port B opens to maintain the pressure set by spring (8). The leakage oil at pilot spool (5) is led to port B internally via control line (13). An optional check valve (3) can be fitted for free flow from port B to A.Sequence valve type DZ .. -.-L5X/ ... X ..(Control lines 4.2, 12 and 13 open; control lines 4.1, 14 and 15 plugged)The function of this valve is principally the same as valve DZ .. -.-L5X/ .... However, on pressure sequence valve type DZ .. -.-L5X/ ... X .. the signal is achieved externally by means of control line (4.2).Sequence valve type DZ .. -.-L5X/ ... Y ..(Control lines 4.1 12 and 14 or 15 open; control lines 4.2, and 13 plugged)The function of this valve is principally the same as valve type DZ.. -.-L5X/.... However, for type DZ.. -.-L5X/ ... Y.. leakage at pilot spool(5) must be drained to tank without pressure via line (14) or(15) . Pilot oil is fed to port B via line (12).Bypass valve type DZ .. -.-L5X/ ... XY ..(Control lines 4.2 14 or 15 open; control lines 4.1, 12 and 13 plugged)Pressure in port X acts on the pilot spool (5) in the pilot valve (2) via control line (4.2). At the same time pressure in port A acts on the spring loaded side of the main spool (7) via orifice (6). When the pressure in port X exceeds the setting value of the spring (8), the pilot spool( 5) is moved against the spring (8 ), fluid can flow from the spring loaded side of the main spool (7) into the spring chamber (17) of the pilot valve (2) via orifice (9) and line (16) and pressure decreases on the spring loaded side of the main spool (7).The fluid can, therefore, flow from port A to B with minimum pressure loss. The pilot oil in spring chamber (17) should be drained to tank without pressure via line (14) or (15). An optional check valve (3) can be fitted for free flow from port B to A.DZ...L5X.pdf