Kalmar ContChamp DRD S Series, Техническое руководство

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ContChamp DRD-S
Technical Handbook
Main valve
Description
39 S. Grupp 70
9407
04-10
Main valve
The main valve is a load-sensing, pressure-compensated direc-
tional control valve of modular type. In the hydraulic system there
are two units, each one comprising:
z Inlet section
z Control section
z Combined control and outlet section
The inlet section is provided with:’
1. Pump connection
2. Tank connection
3. Adjustable pilot-controlled main pressure limiting valve. A
small direct acting pressure limiter controls the spool of the
shunt valve 4 and opens the connection to the tank by moving
the spool when the preset pressure is reached.
The pilot pressure is fed from the supply channel. The load
signal channel is blocked.
4. Shunt valve with two parts, one idling spool and one control
spool. When the main valve spools are in neutral position, the
idling spool is open, e.g. the flow is passing to the tank with
low pressure drop. Whenever a function is being manouvred,
the idle spool will close and the control spool will take over.
The pressure drop over the control spool is determined by the
heaviest load plus the spring power of the shunt valve. This re-
sults in the pump pressure always being higher than what is
required by the heaviest load.
5. A counter pressure valve in the return line with the function to
maintain the pressure in the return line thereby improving the
refill function.
The control section is equipped with:
6. A check valve in the supply line to prevent inadvertent lower-
ing of the load when several functions are operated simultane-
ously.
7. Control section EXTENSION with double-acting, electrohy-
draulically controlled spool for one double-acting function. The
spool is spring-centred.
8. Control section LIFT/LOWER with double-acting, electrohy-
draulically controlled spool for one single-acting function. The
spool is spring-centred.
9. Load sensing valve for transmitting the load signal to the var-
iable pumps for pump activation. The load sensing valve em-
ploys the pump pressure to control a copy spool which, in turn,
is supplied with oil from the supply line to control the pumps.
10.For single acting function, e.g. LIFT/LOWER there is no copy
spool for LOWER.
11.The pressure outlet is protected against overload and cavita-
tion by a combined shock and anti-cavitation valve.
The outlet section has, in addition to 6, 7, 9/10:
12.Anti-cavitation valve in the pressure outlet for refilling and cav-
itation prevention.
13.For single acting function, e.g. LIFT/LOWER there is anti cav-
itation valve only for LOWER. The connection in this case is
plugged.
14.Pressure compensated load signal drain.
15.Load signal connection for pump activation.
1. Pump connection
2. Tank connection
3. Main pressure limiting valve
4. Shunt valve
5. Counter pressure valve
6. Check valve
7. Control spool EXTENSION
8. Control spool LIFT/LOWER
9. Load sensing valve with copy spool
10. Load sensing valve connection plugged
11. Shock and anti-cavitation valve
12. Anti-cavitation valve
13. Plug
14. Pressure compensated load signal
drain
15. Load signal connection for pump
activation
KL1796
4
3
5
6
7
9
9
10
9
12
11
13
8
6
15
14
2
11
1