Vibratory Hydraulic System (OFF)
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| Illustration 1 | g01189102 |
When the engine is running, the fixed displacement vibratory pump generates flow. Supply oil flows to the vibratory manifold. When the vibratory system is off, the vibratory drive solenoid is de-energized. Supply oil flows through the dump valve in the control spool. Supply oil is directed into the charge circuit for the material feed hydraulic system.
Under these conditions, the vibratory motors do not rotate.
Vibratory Hydraulic System (ON)
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| Illustration 2 | g01189156 |
When the paving parameters are met and the screed vibrator switches are in the ON position, the vibratory drive solenoid is energized. The vibratory drive solenoid shifts the vibratory control spool. This action closes the dump valve. This also directs supply oil to the relief valve in the control spool. The relief valve controls the maximum pressure in the vibratory system. Since the passage through the dump valve is closed, pump supply oil must flow through the vibratory control valve.
The flow control valve in the vibratory control valve determines the amount of flow which is forced through the vibratory motors. The volume of flow through the motors determines the vibratory frequency. The flow control valve can be opened in order to decrease the vibratory frequency. The flow control valve can be closed in order to increase the vibratory frequency.