The basic principle.
A valve block is a body containing connected passages and valve functions. It can combine check, relief, metering, bypass and lowering functions while reducing the need for separate external pipe connections.
The exterior does not reveal the whole circuit. A drawing shows how passages and elements connect, while the functional description explains how those connections change during operation.
Three states of a conventional lift circuit.
During ascent, pump flow reaches the actuator through the intended path. At rest, load-holding paths close. During descent, a controlled return path allows fluid back to the tank.
Follow the relationship.
- Supply and protectionManage pump input and pressure limits.
- Movement controlShape lifting and lowering flow.
- Load holdingRestrict unintended return paths at rest.
Connect it to the lift.
Blocks may use mechanical adjustment, electronic feedback or a combination. A symptom such as rough stopping can involve the command, fluid condition, valve response or load. Individual adjustments cannot be understood independently of the whole circuit.
A closer look
Two blocks that look similar can have different internal functions and control sequences. Identification and the correct hydraulic schematic are essential for engineering work.
Check your understanding
Is a valve block just a single large on/off valve?
Reveal the explanation
No. It commonly integrates several interacting functions and passages.