The basic principle.
For a conventional upward journey, the control system coordinates pump operation and valve states so fluid reaches the actuator in a controlled way. Initial bypass or metering can shape the start, depending on design.
As the destination approaches, control reduces actuator flow and brings motion to a stop. The load-holding arrangement then limits return flow while the car is stationary.
Downward travel.
A controlled return path allows fluid to leave the actuator under the load. The valve arrangement shapes speed and stopping; the pump may remain stopped in a conventional gravity-lowering circuit.
Follow the relationship.
- AscentSupply fluid to extend the actuator.
- HoldClose intended return paths.
- DescentMeter fluid back to the tank.
Connect it to the lift.
Fluid conditions and load can influence valve response. Electronic valves and variable-speed pump systems may manage the profile differently from mechanically controlled blocks. A schematic and functional description identify the installed arrangement.
A closer look
Car movement can differ from ram movement in roped systems. Journey analysis must carry the roping relationship through from actuator speed to car speed.
Check your understanding
Is the hydraulic path necessarily the same for upward and downward journeys?
Reveal the explanation
No. Conventional lifting and lowering use different flow paths and control functions.