Tag Archives: fluid power

Fluid Power Seals for Pneumatic Cylinder Systems

continuous molding technologyFluid power seals used in pneumatic cylinder systems represent some of the most overlooked, yet vital components in its construction and operation. Without these rubber seals – or if using inferior seals – the friction and leakage created by the process of using a pneumatic cylinder application could cause the equipment to catastrophically fail, risking severe damage and injury, and requiring great cost to repair or replace.

Gallagher Fluid Seals’ partner, Precision Associates, has innovated to create our own unique and patented compounds for rubber pneumatic piston seals—suitable for all sorts of pneumatic applications. These U-Cups are designed to function with vastly lower breakaway and operating friction than any similar product in the marketplace.

What Are Pneumatic Cylinder Systems?

Utilizing compressed gas as a power source, mechanical pneumatic cylinders produce a reciprocating linear motion force. Like hydraulic cylinders, this force drives a piston in the required direction and the piston is usually a disc or cylinder. The corresponding rod transfers the force it creates to the object requiring movement. Engineers often choose pneumatic cylinders over other methods due to pneumatics being quieter, producing less waste, and requiring significantly less amounts of space for fluid storage.

Pneumatic cylinders can vary in configuration, but generally fit into one of three specific categories: Continue reading Fluid Power Seals for Pneumatic Cylinder Systems

Installation of Linear Fluid Power Seals

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Nathan Wells, application engineer, Engineered Polymer Systems Division.


So, you’ve unboxed the shiny new Parker seals you ordered – now what?  Installing seals for the first time can be challenging without the right know-how and tools. In this article we’ll discuss best practices for seal installation in linear fluid power systems, and how to design your system to make seal installation fast and damage-free.

SEAL GROOVE STYLES

picture of closed rod seal groove

First, let’s look at three common groove styles:

•    Closed
•    Stepped, and
•    Open (or two-piece)

Closed groove

The closed seal groove fully encapsulates the seal and is the most common style used (see Figure 1).

Closed grooves are simple to machine and offer the best support for seals. Since seals in this configuration are surrounded by solid metal, without a well-developed process, installation can be challenging. Rod seals need to be folded to fit into internal (throat) grooves and piston seals must be stretched over the outside of the piston.

picture of cylinder head and piston seals

Notice how both designs shown in Fig. 2 and Fig. 3 utilize static seals (turquoise colored seal) on the opposing side of the dynamic, primary seals. Therefore, installation in either instance requires techniques and tools for both rod and piston seals.

Stepped groove

Typically utilized to ease seal installation, stepped grooves feature a reduced diameter on the low-pressure side of the seal as shown in Fig. 4 and Fig. 5.

picture of rod stepped groove

As shown, the “step” is just wide enough to hold the seal in place as the rod or piston strokes back and forth. This way, seals don’t have to be folded or stretched nearly as much when installing. This design works well for single seals only holding pressure from one direction, like Parker FlexiSeals™.

When using multiple seals stacked in series or in systems with bi-directional pressure, a closed or two-piece groove is needed for support on both sides.

Open and two-piece grooves

Open or two-piece grooves are used when the seal is either too small to be stretched or folded into a closed groove, or if it’s made of a material that doesn’t spring back after flexing.

Figures 6 and 7 show two examples of open grooves. Figure 6 uses a washer and a snap ring to hold the seal in place. Figure 7 uses a bolt-on cap. These groove designs can be used for bi-directional seals, too. As you can see, open grooves cost more to produce but seal installation is a snap.

picture of open rod groove

Open grooves also make removing the seal much easier – useful in systems which require periodic seal replacement. Continue reading Installation of Linear Fluid Power Seals

Fluid Power Applications: Part 3

This article is the third of a three-part series, focusing on common fluid power products, along with a description of the sealing systems that are typically used in those products.  Part 1 and Part 2 on our blog, or you can download the entire Fluid Power Application White Paper by clicking on the image below.

Fluid Power - Applications WhitepaperPiston Type Accumulator
In a fluid power system, piston-type accumulators are used to store pressurized fluid for use when additional fluid volume is required. As shown in Figure 9, a wide floating piston separates a compressible gas from a liquid. In this example, pressurized gas is located on the cavity side of the piston. A floating piston also allows for pressure fluctuation in the system.

Continue reading Fluid Power Applications: Part 3

Modular Seal Kit for Pneumatic Cylinders

Pneumatic CylindersParker Prädifa offers a large number of combined pneumatic seals and wipers for the open groove of the EU system. By installing the right type of seal, a wide range of applications can be covered with just one cylinder. Another advantage – thanks to the open groove, the seals are very easy to install and remove.

For various application conditions
The available materials range from NBR, HNBR to FKM and TPU through to PA-based materials:

  • If extreme resistances, dry-running properties or stick-slip-free operation are required, PTFE compounds or UHMW PE will be used.
  • Further materials can be provided at the customer’s request.
  • The wide range of available solutions can cover temperatures from -200°C to 260°C at a maximum speed of 1m/s.
  • Modified wiper geometries are available to provide protection against ambient influences. Without additional expense to the customer, they prevent ingress of liquids or fluids, viscous media or slight deposits into the cylinder.
  • For anti-torsion piston rods with two flat sides, special seals are available.
  • In case of harsh conditions, the use of split versions is recommended. This means that the material can be optimally adapted to the function of the seal and the wiper lip.

Continue reading Modular Seal Kit for Pneumatic Cylinders

Fluid Power Applications: Part 2

We’ve previously spoken about Fluid Power Sealing Theory and the multitude of options when it comes to selecting the most suitable sealing product for your application.  We also published the first article in this three-part series, which covered a handful of Fluid Power Applications.  This article is the second of a three-part series, focusing on common fluid power products, along with a description of the sealing systems that are typically used in those products.  You can also download the entire Fluid Power Application White Paper by clicking on the image below.

Continue reading Fluid Power Applications: Part 2

Fluid Power Applications – Part 1

We’ve previously spoken about Fluid Power Sealing Theory and the multitude of options when it comes to selecting the most suitable sealing product for your application.  This article will be the first of a three-part series, focusing on common fluid power products, along with a description of the sealing systems that are typically used in those products.  You can also download the entire Fluid Power Application White Paper by clicking on the image below.

Continue reading Fluid Power Applications – Part 1