Fluid power actuator systems use a fluid of some sort, often oil for hydraulics and gas in pneumatic ones, that is enclosed in a piston, rod, and cylinder assembly or other closed system. When the fluid is sufficiently pressurized, it creates linear movement. Common examples include the brakes on a vehicle, the bucket on a frontloader, or an elevator car. The key to this type of movement is reliable fluid pressure, so it’s critical to ensure the fluid is sealed inside the system.  

Leaks can cause lower and inconsistent power, costly repairs and downtime, and even pose safety hazards to workers, passengers, and the surrounding environment. There are a variety of fluid power sealing solutions that effectively close gaps between moving parts and around valves and joints. Pneu-Draulics is a leading supplier of fluid sealing rings and products for hydraulic systems. Learn more about these seals and their uses.

About Fluid Power Sealing Solutions

There are multiple types of fluid power seals for hydraulic systems, and they are generally made from elastomers like fluorocarbon, nitrile, or urethane, which can withstand high pressures and are compatible with the oil or other system fluid. Seals fall into two broad categories: 

  • Static seals sit in a groove between two stationary parts to create a seal.
  • Dynamic seals sit at points where components move past each other or relative to each other, such as a piston rod and cylinder. They must be able to stay securely in place while the parts are moving.

Pneu-Draulic’s comprehensive selection of seals for hydraulic systems includes: 

O-Rings

O-rings are a simple type of static seal. They have a circular, or O-shaped, cross-section and sit snugly in a groove between components. When the components are squeezed together, the ring is compressed and closes any potential gaps between the components. This seals the pressurized fluid inside.  

O-rings have a simple profile that is simple to manufacture in many dimensions, and can be cost-effective. They are also easy to install by placing them into the proper groove between parts. 

V-Ring Seals

V-ring seals are mounted to the cylinder shaft and help keep fluid and lubricants inside hydraulic or pneumatic systems. They have a V-shaped cross-section, and one lip of the seal usually sits against a surface that is perpendicular to the cylinder. Because the center of the ring is angled inward and has a smaller circumference than the outer edges, the outer edges form a tight lip that prevents leaks. The shape also reduces friction for better overall performance.  

Piston Ring Seals

These dynamic seals create a seal between the piston and the cylinder wall inside the assembly. As the piston moves, this seal presses tightly against the interior walls to ensure fluid cannot leak out and that the fluid maintains optimal pressure levels. 

Rod Seals

These dynamic seals maintain the seal around the rod where it enters and exits the cylinder. They help keep an even pressure and seal out contaminants that could get inside the cylinder. While they are similar in function to piston seals, rod seals are often made of a more flexible material. Rod seals are frequently used in conjunction with buffer seals, which help protect the rod from excessive vibration and shock during operation.

Wiper Seals

Also called scraper seals, wiper seals sit on the outside of the cylinder head, in contact with the rod as it retracts into the cylinder. The pressure from the seal prevents dust, dirt, or particles from entering the cylinder and causing damage.

U-Cups

U-cup seals are ring-shaped and have a profile shaped like the letter U. This shape allows the seal to press tightly into position, even in highly pressurized systems, and they can work in both static and dynamic environments without requiring an initial compression force to create the seal. U-cups can fit in gland spaces as little as 110% of the height of the seal. Their unique shape creates little friction and resists extrusion as well.

Industries That Rely on Fluid Power Sealing Technologies

Fluid power seals are widely used in many industries for equipment and vehicles. Common industry uses include:

  • Chemical processing: Hydraulic presses and actuators for opening and closing valves
  • Pharmaceuticals: Pumps, mixers, and valve controllers for product flow
  • Food processing: Hydraulic juice and oil presses, conveyance systems, and filling line equipment
  • Oil and gas: Pumps and compressors in offshore platforms and refineries
  • Power generation: Pumps and turbines  
  • Water and wastewater management systems: Pumps for sewage and water treatment
  • Aerospace: Landing gear, flight controls, wing flaps, and braking systems
  • Automotive: Steering, brakes, and suspension systems
  • Construction: Actuation for arms, levers, and buckets in heavy equipment for earthmoving and digging

Fluid Power Solutions at Pneu-Draulics

High-quality seals for fluid power systems reduce the risk of leaks, contamination, and depressurization, which lead to processing inefficiencies, equipment damage, and safety hazards. Pneu-Draulics is a trusted supplier of standard and custom gaskets and seals. We are ISO 9001:2015 certified, and our capabilities include extruding, injection molding, and die, laser, and water jet cutting. In business since 1982, we are a trusted partner for as-needed, contract, or just-in-time manufacturing, and custom kitting, labeling, and packaging. 

Contact us to learn more about our products and services, or request a quote to start your order.