All posts by GFS Marketing

Case Study: 3-A® Compliant Rod Seal Capable of Handling High-Pressure

Valves are indispensable components in the hygienically sensitive systems used in the food, beverage and pharmaceutical industries. Until now, there were no high-pressure valves available for food-product contact applications that conformed to 3-A® standards. These global hygiene standards address the design and manufacturing of components that come into contact with food.

Bardiani Valvole approached Gallagher’s partner, Freudenberg Sealing Technologies, for help in developing a solution to tap into its material expertise. As a result of joint cooperation, Freudenberg engineers developed a main rod seal that was both 3-A® compliant and capable of handling high-pressure of up to 2175 psi (150 bar) that the customer’s valve required. The main rod seal incorporates proven Freudenberg technology with advanced component design in an entirely new combination that is also compatible with other industrial high-pressure valves.

picture of valve example
Copyright: Bardiani Valvole Spa

Prototypes produced without any tools

The 3-A® compliant main rod seal combines a sealing lip, manufactured from EPDM 302 or Fluoroprene® XP 43, with a backup ring made of PTFE. Freudenberg’s product engineers were inspired by the design of a proven shaft seal and an O-ring with a backup ring. In order to meet development and cost deadlines, the team initially produced one-off prototypes to share with Bardiani Valvole using the unique capabilities of Freudenberg Xpress®, a fast turnaround, high-quality manufacturing service that can generate custom seals in as little as a day. It offers machined seals made of original materials and original profiles for prototypes, spare parts or economical small series.

By eliminating the need to set up manufacturing tooling to produce sample parts, this results in considerable cost and time advantages for the customer. Thanks to special turning and milling techniques, individual designs can be tuned to exact specifications. The tailor-made sealing solution for the new high-pressure valve could also be produced economically in an extremely short time. The Freudenberg Xpress® Service is represented at numerous Freudenberg sites worldwide, enabling rapid delivery of spare parts, for example.

The seal’s design is free of dead space and prevents residue infiltration from process and cleaning media. It is hygienic, easier to clean, and compliant with all relevant material specifications for food, beverage, and pharmaceutical industry applications. Both materials used have very good thermal resistance and excellent mechanical properties. They also meet the demanding requirements for use in Cleaning in Place and Sterilization in Place (CIP/SIP) processes. Continue reading Case Study: 3-A® Compliant Rod Seal Capable of Handling High-Pressure

How Much Do You Know About Compressive Stress Relaxation? CSR Part 1

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

Original content can be found on Parker’s Website and was written by Dan Ewing, senior chemical engineer, Parker Hannifin O-Ring & Engineered Seals Division.


black o-ringsCompressive Stress Relaxation (CSR) is a means of estimating the service life of a rubber seal over an extended period of time. As such, it can be thought of as the big brother of compression set testing. Rather than measuring the permanent loss of thickness of a compressed rubber specimen as is done in the compression set, CSR testing directly measures the load force generated by a compressed specimen and how it drops over time. In part 1 of our blog series, we will explore the theory of CSR testing, common test methods, and how CSR differs from compression set testing.

Theory of Compressive Stress Relaxation Testing

To understand the value of CSR testing and how it differs from compression set testing, it is helpful to return to the basic theory of how a rubber seal functions. In a standard compressed seal design, a rubber seal is deformed between two parallel surfaces to roughly 75% of its original thickness. Because the material is elastic in nature, the seal pushes back against the mating surfaces, and this contact force prevents fluid flow past the seal, thus achieving a leak-free joint. Over time, the material will slowly (or perhaps not so slowly) relax. The amount of force with which the seal pushes against the mating surfaces will drop, and the seal will become permanently deformed into the compressed shape. In compression set testing, the residual thickness of the specimen is measured, and it is assumed that this residual thickness is valid proxy for the amount of residual load force generated by the compressed seal. In CSR testing, the residual load force is measured directly.

In practice, compressive stress relaxation results are typically presented very differently from compression set results. In CSR testing, it is common to see multiple time intervals over a long period of time (3,000 hours or more of testing), thus allowing a curve to be created (see Figure 1). In practice, however, specifications are written such that only the final data point has pass/fail limits. In compression set testing, it is common to see a single data point requirement with a single pass/fail limit. Multiple compression set tests can be performed to create a curve, but this is almost always done for research purposes rather than for specification requirements. In most cases, compounds that excel in compression set resistance also demonstrate good retention of compressive load force over time. However, there are exceptions.

Figure 1: Typical CSR curve. These results display a fluorocarbon seal material immersed in engine oil at 150°C.

Continue reading How Much Do You Know About Compressive Stress Relaxation? CSR Part 1

Can I Use a Metal Hose for Food Applications?

That’s a Tricky Question…

A question we are frequently asked by our customers is “Can I use a metal hose for food-related applications?” It’s a simple question, but the answer isn’t always so simple.

The quick answer is no, metal hose generally cannot be used for the transfer of food-grade materials. This has nothing to do with the capabilities of the manufacturer or the quality of materials used in the hose. On the contrary, while the steel used may indeed be “food-grade,” the corrugations in the hose can potentially trap food media and make it difficult to clean the hose to the proper standard. Instead, you typically see PTFE hoses in these types of applications. The only exception to this would be if the media is at a temperature high enough to kill off any bacteria, which may allow for a metal hose to be used in some cases.

However, just because metal hose generally cannot be used to transfer food-grade materials does not mean that there are not applications for metal hose elsewhere in production! You just have to know where to look for them…

Metal Hose for Food Industry Applications

Clean in Place Systems

A key component of food production that requires the use of metal hose is clean-in-place (CIP) systems. Clean-in-place systems serve as a way to clean and sanitize the internal surface of a piping system as part of the routine cleaning of the production line or when production is being changed over to a different product. These systems utilize steam and chemicals (such as sodium hydroxide) to clean the piping system, which can be hard on any non-metal hoses that are used in the system. Instead, non-metal hoses are removed to be cleaned separately and metal hoses are installed in their place during the cleaning process. These metal hoses are better suited to handle the high heat and caustic cleaning solution running through the system, making metal hose an optimal solution for this application. Continue reading Can I Use a Metal Hose for Food Applications?

Preventing Seal Failure

Seals are small components that have a big function. At their most essential purpose, they keep fluid in and debris out. Failure to do this can lead to costly machine destruction, and even endanger the lives of people working around these machines. Preventing seal failure is very important on many different levels.

What Seals Are Up Against

Many factors can cause a seal failure. Being aware of these factors will help you in preventing an avoidable failure. Seals are under constant pressure because of the liquid or gas being contained. Typically, the seals in pipes or machinery have some type of matter within transferred at high velocities. This is a huge part of what they were designed to do, but too much or too little pressure could wear down the seals.

In addition, extreme temperatures can cause the seal to become brittle. A mixture of extreme temperatures and pressure is a recipe for cracking and leaking. Also, debris can contaminate the integrity of the seal. Even in clean environments, the small shavings from pistons or hydraulics can get into the seal. Chemical compounds can cause a much faster seal breakdown, so be aware of what type of matter stays concealed. Finally, time will cause the seal to break down. There is no way to avoid this one, so ensuring you mitigate the other factors can help the longevity of a seals life.

Different Types of Seals

Each seal has a specific purpose and function. Putting the right seal in the right environment will help you have a more successful operation.

  • Types of O-Ring ApplicationsO-rings are the most popular type of seal. They are meant for static conditions and can conceal liquid and gas.
  • Rod seals should work with hydraulic cylinders. They typically work best with concealing fluid and can withstand movement.
  • Piston seals should also be used with hydraulics, but specifically pistons instead of cylinders.
  • Wear rings find usage in sewage pumps mostly. They are used to decrease the leakage around an impeller, which is the rotor that increases the flow of liquid.

Preventing Seal Failure: How To

These are the main points of failure for seals and the best ways to avoid them:

  • Install the seal properly. Even with improper installation, a seal can work initially, but it will fail much quicker. Seals need to have the exact size for a precise fit. Or they will fail. Make sure to get the correct seal for the area in which you plan to install it.
  • Cleanliness is paramount. Although it is important to keep debris away from the seals, that is not where cleanliness needs to begin. You also need to make sure that the area is clean of debris during installation.
  • Find the proper rating for the environment. Seals have different ratings for temperature and pressure. Make sure the seal can handle these two factors for longevity.
  • The finish of the seal and the shaft need to match. You can’t have a smooth shaft with a seal that has edges or burrs. Anything that can be caught or cause friction will create debris. This mismatch can also throw the seal out of alignment.
  • Ensure all other parts of the machinery are functioning correctly. An anomaly somewhere else can cause undue stress to the seals.
  • Periodically check the fluid conditions. The purpose of a seal is to prevent leaks, but too much or too little fluid can cause damage. Verifying the fluid conditions stay consistent will keep the seal in good shape.
  • Replace seals promptly. This one comes more with experience. Always replace seals before they get too worn to stay effective.

The original article was written by staff at Real Seal and can be found on their website here.

For more information about seal problems you are having and how Gallagher Fluid Seals can help, contact our engineering department.

Eclipse Announces MicroLip™ Prototype Program

picture of microlip rotary

Eclipse has been working hard during the Covid-19 downtime on finding solutions to issues that customers have brought to the table over the past few years.

Many new designs have been sent into testing while focusing on processes that will help improve productivity and lower costs.

The MicroLip™ is an example of a viable solution to rotary seal issues that many customers have struggled with. This is especially true when the order volumes are relatively low or the shaft diameters are small, such as with encoders or chemical-processing facilities.

The Eclipse MicroLip™ Prototype Program

When moving from rubber to Teflon lip seals, Eclipse has found that the cost to bring the product to market is often a hindrance. The high cost is due to tooling and the number of pieces that must be manufactured to make the product viable in the prototype phase.

Because of this, many customers sneak by using inappropriately-applied rubber lip seals to solve rotary seal problems.

MicroLip™ seals have proven to be a powerful component in rotary services. Since the MicroLip’s inception, it has been applied to a variety of applications including mobile hydraulics, robotics, surgical drills, and semiconductor processing and encoders.

Over the last 3 years, Eclipse has designed and manufactured various styles of MicroLips in diameter sizes of under 1/8 inch (5mm) and over an inch. Since the components of the MicroLip™ can be machined, Eclipse has made the seal in quantities of less than 10, and batches in the thousands. Continue reading Eclipse Announces MicroLip™ Prototype Program

Garlock’s New Isolation Gasket: The Future of Flange Isolation

The Garlock Family of Companies has launched a new fully-coated isolation gasket known as EVOLUTION.

picture of garlock evolution isolation gasket

EVOLUTION® Isolation Gaskets

The next generation of isolation gaskets, EVOLUTION®, features easier installation, tight sealing, high-temperature operation, no permeation, hydrotesting isolation, fire-safety and chemical-resistance.

Featuring a thinner, 1/8-inch design, EVOLUTION minimizes the difficulties encountered when attempting to install thicker isolating gaskets. The full-coating encapsulation allows the gasket to be hydrotested and left in the pipeline with the same isolation properties as before it was tested.

EVOLUTION’s coating is highly resistant to abrasion and impact while providing chemical resistance to hydrogen sulphide (H2S), steam, carbon monoxide, carbon dioxide and other chemicals often found in oil and gas pipelines. This fully encapsulated coating also prevents the need for expensive exotic cores, as it eliminates contact to exposed metal. Continue reading Garlock’s New Isolation Gasket: The Future of Flange Isolation

How to Properly Choose Commercially Available O-Ring Cross Sections

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

Original content can be found on Parker’s website and was written by Dorothy Kern, applications engineering lead, Parker O-Ring & Engineered Seals Division.


There are 400+ standard O-ring sizes, so which is the right one for an application? Or maybe you are wondering if one O-ring thickness is better than another. This short article will walk through some of the design considerations for selecting a standard, commercially available O-ring for an application.

Design Considerations

Hardware geometry and limitations are the first consideration. A traditional O-ring groove shape is rectangular and wider than deep. This allows space for the seal to be compressed, about 25% (for static sealing), and still have some excess room for the seal to expand slightly from thermal expansion or swell from the fluid.  Reference Figure 1 as an example. Once the available real estate on the hardware is established, then we look at options for the O-ring inner diameter and cross-section.

AS568 Sizes

From a sourcing perspective, selecting a commercially available O-ring size is the easiest option.  AS568 sizes are the most common options available both through Parker and from catalog websites.  A list of those sizes is found in a couple of Parker resources including the O-Ring Handbook and the O-Ring Material Offering Guide. They are also listed here.  The sizes are sorted into five groups of differing cross-sectional thicknesses, as thin as 0.070” and as thick as 0.275”, shown in Table 1 below.
Continue reading How to Properly Choose Commercially Available O-Ring Cross Sections

Freudenberg Sealing Technologies Launches Modular Sealing Unit

Freudenberg Sealing Technologies has developed a new, innovative sealing concept for small, electric household appliances. // Copyright: Freudenberg Sealing Technologies 2020

Freudenberg Sealing Technologies has launched series production of a modular sealing unit that combines a classic radial shaft seal with a plastic outer case. The design promotes better long-term seal performance and longevity, is easier to assemble, and significantly lowers manufacturing costs in comparison with traditional metal-encased radial shaft seal units. Freudenberg has developed the innovative sealing concept for use in general industry applications that are especially focused on small, electric household appliances.

Whether it’s to knead bread dough, mix a cake batter, puree soup ingredients or blend a smoothie, most people reach for an electric kitchen appliance to get the job done. The durability of the appliance depends largely on how well the seal at the outlet point of the drive shaft protects the interior from ingress of food residue or liquids. Seals made of high-quality elastomers or the polymer polytetrafluoroethylene (PTFE) combine low wear with excellent long-term resistance against leakage. In the past, a metal case was the best option available to maintain the integrity of the seal’s performance over a long period of time. Freudenberg Sealing Technologies has now succeeded in developing a modular sealing concept with a plastic case that meets the specific requirements for long-term performance as well as those made of metal. There are three major advantages to the new design: Significantly, in the price-sensitive, small appliance industry, the lower production costs associated with forming enclosures from plastic is an important consideration. In addition, Freudenberg’s modular sealing unit concept accommodates the integration of additional components, such as shaft bearings. Finally, because small appliance housings are typically made from plastic, fastening the seal case to the appliance housing is easier to achieve. Continue reading Freudenberg Sealing Technologies Launches Modular Sealing Unit

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

Designing Cryogenic Seals for High and Low Temperature Sealing

cryogenic

When designing for low temperature sealing, the first step is to define the temperature range that the seal will be operating in.

Typically, cryogenic as seals are those that are operating below -65 Fahrenheit. Gallagher’s partner, Eclipse, chooses this benchmark because they currently have elastomers that have a usable TR10 value at this temperature.

When designing at this level — with high temperatures around 300 Fahrenheit — an understanding of what level of leakage control is required on the low temp end. Seals that operate in aircrafts must function within this range.

However, there may be an allowable leakage rate which allows for reduced drag. When requiring zero leak, the drag in the system is often increased to support some elastomeric contact with a dynamic surface. In the case of static seals, elastomers span this range although increased squeeze may be necessary.

Eclipse Engineering routinely designs in the range indicated above.

While -65 Fahrenheit is extreme cold, it’s not considered cryogenic. Liquid nitrogen at -320° Fahrenheit (-195°Celsius) requires special hardware and seal material consideration.

To begin, many projects and applications don’t utilize lubricant in dynamic applications. To improve sealability, a better-than-average surface finish is required.

Surface finish often holds lubricity. But without this, a smooth finish reduces friction, improves life, lowers drag, and improves sealability.

Static seals are often required to have leak rates approaching zero; meaning hardware considerations and surface can be even more important. This may mean polishing the groove, which in some applications can be very challenging.

Cryogenic Seal Materials

The next criteria are the seal materials. Elastomeric materials lose their flexibility at these extreme temperatures, so Eclipse relies on polymer-type materials to bridge the gap. When we experience temperatures below -180° Fahrenheit ( -195° Celsius), that’s when it becomes wise to move away from basic PTFE to modified fluoropolymers such as PCTFE, known for operating down to -460 Fahrenheit. Continue reading Designing Cryogenic Seals for High and Low Temperature Sealing