Hydraulic Seals…Introduction

Hydr1Hydraulic Seals 

are relatively soft, non-metallic rings captured in a groove or fixed in a combination of rings, to form a seal assembly, to block or separate fluid in reciprocating motion applications. Hydraulic seals are vital in machinery. Their use is critical in providing a way for fluid power to be converted to linear motion.

Types of Hydraulic Seals

A Static Hydraulic Seal is located in a groove and sees no movement and only sealing within its confined space. E.g. cap seals, flange gaskets

A Dynamic Hydraulic Seal called a Rod Seal is exposed to movement on its inner diameter along the shaft or rod of a hydraulic cylinder.

A Dynamic Hydraulic Seal called a Piston Seal is exposed to movement on its outer diameter along the tube or bore of a hydraulic cylinder.

Hydraulic seals are made from a variety of materials such as…

  • Polyurethane
  • Rubber
  • PTFE

The material used will depend on the specific operating conditions, e.g.

  • Fluid type
  • Pressure
  • Temperature

Poly-SealPolyurethane is the most common material used in the manufacture of hydraulic seals as it is…

Abrasion Resistant
Polyurethane Hydraulic Seals will often outwear other materials by large margins especially in abrasive conditions. Polyurethane is proven superior to plastics, rubber and even metal in many applications.

Weather Resistant
Polyurethane hydraulic seals have an outstanding resistance to general weather conditions.

Tear Resistant
Tear-strength range of polyurethane hydraulic seals is far superior to rubbers. As a result, urethane is also often used as drive belts, diaphragms, roll covers, cutting pads and many other products

Oil and Solvent Resistant
Polyurethane hydraulic seals have excellent resistance to oils, solvents, fats, greases and petroleum products.

Load Bearing Capacity
Polyurethane has a high load-bearing capacity and because of this characteristic not only is it an ideal material for hydraulic seals but also for load wheels, heavy duty couplings, metal-forming pads, shock pads, expansion joints and machine mounts.