Pressure Shut-off Valve DAW

Established in 1979, Huade Hydraulic has cooperated with Bosch Rexroth twice. The two long term cooperation enable Huade® pressure valves to reach the same level as Rexroth products. Type DAW pressure shut-off valves can replace the same series from Rexroth with a lower price. As a leading brand in China's hydraulic industry, all branches of the enterprise have passed ISO9001, ISO14001 and OH SAS18001. Huade® pressure shut-off valve DAW has passed CE certificate. Huade® pressure valves has won wide market recognition and user trust.

Product parameter of Pressure Shut-off Valve DAW

Product Feature And Application of Pressure Shut-off Valve DAW

Features:

▶ For subplate mounting:

▶ 4 adjustment elements:

● Rotary knob

● Sleeve with internal hexagon and protective cap

● Lockable rotary knob with scale

● Rotary knob with scale

▶ 3 pressure ratings

▶ Solenoid actuated unloading via a built-in directional valve

Application:

Pressure control valves type DAW are pilot operated pressure shut-off valves. They are used to switch a pump flow over to unpressurised by-pass as soon as the accumulator loading pressure is reached. Further applications for the valve are in systems that have high and low pressure pumps. In this case the low pressure pump is switched to unpressurised by-pass as soon as the set high pressure is reached.

Section And Symbols of Pressure Shut-off Valve DAW

Pressure shut off valves basically consist of the main valve with the main spool assembly, pilot valve with pressure adjustment element and check valve. In size 10 valves, the check valve is built into the main valve. In valve sizes 25 and 32 the check valve is built into a separate plate installed under the main valve.

Pressure shut-of valve type DAW

Diverting pump flow from P to A or P to T.

The pump delivers flow via check valve (1) into the hydraulic system (P to A). Pressure in port A acts via pilot line (3) on the pilot control spool (4). At the same time, pressure in port P passes via orifices (5) and (7) to the spring loaded side of the main spool (6) and poppet (8) in the pilot valve (2). As soon as the set cut-off pressure in the hydraulic system is reached, the poppet(8) lifts off against spring(9). Pressure fluid now flows via orifices(5) and(7) into spring chamber(11). From

here, the fluid is returned to tank either internally via control line in valve type DA...30B/... or externally via control line in valve type DA.30B/..Y... Due to orifices(5) and (7), a pressure drop is now present at the main spool (6). The main spool(6) now lifts off its seat and opens the connection from P to T. The check valve(1) now doses the connection from A to P. The poppet(8) is now held open by the system pressure via pilot spool (4).

Diverting pump flow from P to T or P to A.

The area of the pilot spool (4) is 17% greater than effective area of the poppet(8). The effective force on the pilot spool (4) is, therefore, 17% greater than the effective force on the poppet (8) . When the actuator pressure falls in relation to the cut-off pressure by a valve which corresponds to the switching pressure differential, spring(9) pushes poppet(8) on to its seat. Pressure is then built up on the spring loaded side of the main spool(6).In conjunction with spring(10), this closes the main spool(6) and isolates the connection from P to T. The pump flow passes once more via the check valve (1) into the hydraulic system(P to A).

A solenoid actuated directional valve(12) can, however switch the set cut-off pressure which is under the pilot valve (2) either from P to T or form P to A.

structure of DAW20,30 ...30B

Symbols of DAW...30B