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 worked-through example

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.

One circuit, three journey states.

Follow the same pipes through three different states. This example uses a single-acting cylinder, a fixed-delivery pump and gravity lowering. The drawings show the steady part of each state; a real valve block also manages the transitions.

1. Ascent

Pump running · load rising

1. Ascent in a conventional hydraulic lift circuitFluid travels from tank through pump and open check valve to the cylinder. The bypass and lowering paths are closed in this simplified steady-ascent state.UP123456

Fluid travels from tank through pump and open check valve to the cylinder. The bypass and lowering paths are closed in this simplified steady-ascent state.

2. Hold

Pump stopped · load held

2. Hold in a conventional hydraulic lift circuitNo through-flow. The check valve seats against return flow and the lowering valve is shut. Cylinder pressure supports the load. The pump-side bypass is open but carries no flow.STILLPressureheld123456

No through-flow. The check valve seats against return flow and the lowering valve is shut. Cylinder pressure supports the load. The pump-side bypass is open but carries no flow.

3. Descent

Pump stopped · load lowering

3. Descent in a conventional hydraulic lift circuitThe load drives fluid from the cylinder through the metering lowering valve back to tank. The check valve blocks the reverse route through the pump. The bypass remains open with no pump flow.DOWN123456

The load drives fluid from the cylinder through the metering lowering valve back to tank. The check valve blocks the reverse route through the pump. The bypass remains open with no pump flow.

  1. Tank. Stores the fluid and receives the return flow.
  2. Pump. Delivers fluid during ascent. It is stopped in the holding and gravity-lowering states shown.
  3. Check valve. Opens for supply towards the cylinder; reverse pressure seats the ball in this simplified picture.
  4. Bypass path. Returns pump delivery to the tank when open. It is shown shut during steady ascent. Opening it progressively can reduce cylinder flow during levelling; it is a different function from pressure relief.
  5. Lowering path. Meters the cylinder’s return flow. Shut for ascent and hold; open by a controlled amount for descent.
  6. Cylinder. Incoming fluid extends the actuator. During descent, the supported load pushes fluid back through the lowering path.
Read the lines: solid orange lines with arrowheads carry the flow shown. Dashed grey lines have no through-flow in that state; they may still contain pressurised fluid. A thick bar closes a valve path; a gap opens it, and opposed points indicate a metering restriction. These are simplified teaching pictograms, not a complete ISO hydraulic schematic. Relief protection, pilot passages and installation-specific protective devices are omitted so the journey paths remain clear. They remain essential parts of the real design; see hydraulic rupture protection.

Why the bypass matters: pump delivery divides between the cylinder and any open bypass path. Reducing cylinder flow reduces actuator speed. During conventional descent the energy comes from the lowering load, and controlling the return flow controls the speed.

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.

Further reading.

Optional reading to explore this lesson in more detail.

  • Blain: service manual (PDF)

    Technical example: the journey curves on page 8 connect valve operation with acceleration, travel, levelling and stopping.

  • Blain: EV / KV service manual (PDF)

    Compare the check, bypass and lowering functions labelled on pages 4–5 with the EV100 journey curves on page 8. The teaching circuit simplifies these functions; it does not reproduce the installed schematic.

  • Bucher Hydraulics: VF-LRV

    An alternative approach: a frequency converter acts on the motor and pump, while the valve includes flow measurement. Compare this with the fixed-delivery-pump example above.