What is hydraulic elevator cylinder seal?

Basic Components of a Felt Kit

In the neck (head) section of an elevator cylinder, an integrated set of seals typically serves instead of a single seal:

• Rod Seal: This is the main sealing element of the system. It resists the dynamic pressure inside the cylinder, preventing oil from escaping around the piston rod.

• Wiper Seal: Located on the outermost part of the cylinder. It prevents dust, mortar, metal shavings, and debris from being carried into the cylinder as the piston rod enters.

• Bearing Elements (Guide Bands): Ensure smooth axial movement of the piston shaft within the cylinder housing, prevent metal-to-metal friction, and withstand radial (lateral) loads.

• O-Rings and Support Rings (Static Sealing): Prevent leaks in fixed areas between the cylinder liner and the cylinder head (flange).

Functions and Importance

Duty	Function
Pressure Holding	It ensures the cabin remains stable at floor level under load; it prevents pressure drop.
Preventing External Leakage	It prevents oil from seeping to the bottom of the well, thus preventing environmental pollution and oil loss.
System Protection	It prevents external particles from entering the hive and scratching the surfaces.

What happens if the felt wears out or deforms?

1. Floor Drop (Level Loss): When the seal wears down, oil leaks under pressure, causing the elevator to sink millimeter by millimeter while stopped at the floor level.

2. Oil Accumulation at the Bottom of the Well: Oil leaking from the cylinder head accumulates at the bottom of the well or in the collection container.

3. Gradual/Jumping Movement: When bearing belts and seals dry out or deform, jolting (stick-slip) occurs during starts and stops.