Sealing rings for metallurgical hydraulic cylinders are one of the key components for cylinder sealing. Cylinder sealing belongs to dynamic sealing, which is further divided into rotary sealing and reciprocating sealing by function; sealing for metallurgical hydraulic cylinders falls under reciprocating sealing. There are various types of reciprocating seals, with different structures and materials. Below is an introduction to how to select the structure, material, and model of sealing rings based on the characteristics of metallurgical hydraulic cylinders.

What are the characteristics of metallurgical hydraulic cylinders?

First, due to the harsh working environment in the metallurgical industry, metallurgical hydraulic cylinders often operate under conditions of high temperature, high pressure, high radiant heat, and multi-medium exposure. During operation, the cylinders act relatively frequently, with the liquid pressure inside reaching up to 30–40 MPa and the oil temperature approaching 200°C. Therefore, cylinders require high stability and durability, and maintenance is relatively cumbersome.

What types of sealing rings are generally suitable for metallurgical hydraulic cylinders?

Cylinder sealing includes dynamic sealing and static sealing. For static sealing, O-ring seals (or O-ring seals with backup rings for high pressure), rectangular seals (or rectangular seals with backup rings for high pressure) are commonly used; X-ring seals can be used occasionally. In most cases, static sealing materials are made of NBR rubber. When the operating temperature exceeds 100°C, special material selection is required. The following introduces the models of reciprocating seals for metallurgical hydraulic cylinders, classified by function and structural form.

1. Classified by function:

   Rod seals (lip-type, Y-type, U-type), piston seals, and wiper seals (combination rings).

2. Classified by structural form of seal products:

   Lip-type reciprocating seals and combination seals.

3. Another type of seal for reciprocating motion:

   Guide rings (also called support rings or wear rings), which function to guide the piston or piston rod and absorb radial forces.