- Valves that impede the flow pipe to control the oil flow volume in order to speed hydraulic motors and cylinders can be controlled on a fixed displacement hydraulic pump is used.
- Throttle
- Valve which controls the flow by blocking resistance in the valve, but changes according to the change of pressure before and behind the valve. This valve can be set in a simple (niddle valve) or fixed barriers to the flow (orifice).
- Flow control valve with pressure compensation
- This valve has a pressure compensation mechanism to keep the pre-design pressures difference before and behind the throttle valve. By doing this, the flow volume can be kept constant regardless of fluctuations in pressure before and behind the valve. Design orifice pressure compensation will normally provide yagn viscosity changes due to temperature. Some designs may have springs made of bi-metal that will compensate for temperature changes.
Flow divider valve
Valve which divides the oil flowing into the two hydraulic flow which has a different pressure than the source of power regardless of the pressure flow. This type of valve can be used to divide the flow of the hydraulic pump or source into two separate chain crawler tractor steering. Both of these series can operate, independently of the other. In industrial applications, where the flow should be divided with a very accurate or if the flow is divided into more than two streams, then there must be some means of rotary flow divider installed and connected to the hydraulic motor.
Directional control valve
The drain valve or stop the flow of oil flow so that the actuator can be operated to come forward or back and hold it in the middle, and dioperasikn with external power (manpower, solenoid or mechanical power).
Directional valves are manufactured with many configurations depending on the number of doors and operating position but the valve is commonly used for the hydraulic circuit will be the valve spool type 2 posisis – 4 way (2/4) or 3 positions – 4 way (3/4). In earthmoving machinery, valves directionalnya for blade, dump body, buscket could have 4 positions (4/4), the next position will provide a full cylinder float.
Common center position on the 4/3 way valve
Figure below shows about 4/3 way valve with a wide range of middle position and is accompanied by a brief description of the method of operation:
Center position valve 4/3-way “recirculation pump” (tandem center).
Center position valve 4/3-way “closed” (flashlight closed).
Middle position “H” valve 4/3-way (open flashlight).
Four ports that interconnect: relif power components and hydraulic pump (eg. The cylinder can be changed).
Center position valve 4/3-way “power lines exhausted” (floating flashlight).
