Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Website and was written by Nathaniel Reis, Applications Engineer for Parker O-Ring & Engineered Seals Division.
In our semiconductor entry from last month, we noted that lowering the cost of ownership is a multi-faceted goal. We discussed how one of the areas for potential improvement
But what’s great for an individual customer – a cherry-ginger-lime cream soda, for example – can play havoc with the elastomer seals inside the machine. Add in hygienic cleaning requirements and proper food contact certifications and equipment manufacturers can find themselves spending months chasing challenges like flavor transfer, leaks and material compliance approvals.
Freudenberg-NOK Sealing Technologies, a leading specialist in advanced sealing applications, has a portfolio of solutions to resolve these issues. The company, which runs the business operations for Freudenberg
The O-Ring & Engineered Seals Division of Parker Hannifin Corporation, the global leader in motion and control technologies, recently announced the launch of VA179, a new extreme high temperature fluorocarbon (FKM) compound. VA179 is an innovative, 70 durometer rubber seal material providing increased high temperature limits while maintaining chemical resistance and low temperature sealing consistent with standard FKMs.
VA179 consists of a breakthrough rubber technology increasing the FKM continuous high temperature limit an additional 20°C (68ºF) over standard FKM materials on the market today. This provides a new industry sealing solution to long-term compression set issues for customers using traditional fluorocarbons and silicones.
"In markets such as aerospace, automotive, and heavy-duty, we are frequently challenged to expand the temperature capabilities of our rubber compounds,” says Nathaniel Sowder, aerospace, military and chemical processing business development engineer, O-Ring & Engineered Seals Division, “With the launch of VA179, we now have a solution that will reach higher temperatures without sacrificing the low temperature and chemical resistance attributes that make standard FKM such a popular choice.”
Gallagher recently released our High Performance Elastomer Seals for the Instrumentation Industry White Paper. This was written by Russ Schnell, an Elastomer Consultant contracted by Gallagher Fluid Seals, and a former Senior Application Engineer with the Kalrez® perfluoroelastomer parts business at DuPont. This white paper is now available for download on our Resources page.
Below is the third and final section of the white paper, which will discuss the importance of proper seal and groove design.
Proper seal design is a necessity for elastomer seals to perform reliably over the long term. Many of the instrument applications mentioned above use o-ring seals. The suggested compression for an elastomer o-ring seal to perform properly is typically a minimum of 16%, and a maximum of 30%. However, this range must also take into account the thermal expansion of an elastomer at elevated temperatures as well as any swell due to chemical exposure. Many of the elastomer seals used in instruments are small o-rings, which can create design issues. This is especially true for perfluoroelastomer parts which have a relatively high coefficient of thermal expansion (CTE). Fluoroelastomers have a lower CTE, making seal design easier at elevated temperatures.
Gallagher recently released our High Performance Elastomer Seals for the Instrumentation Industry White Paper. This was written by Russ Schnell, an Elastomer Consultant contracted by Gallagher Fluid Seals, and a former Senior Application Engineer with the Kalrez® perfluoroelastomer parts business at DuPont. This white paper is now available for download on our Resources page.
Below is the second section of the white paper, diving into applications where the measurement is made in analytical laboratories which employ numerous solvents in a wide range of analyses and test equipment.
The final set of instrumentation is laboratory test equipment. As opposed to the laboratories in chemical plants, which often perform the same routine analyses on plant process streams, general analytical labs employ numerous solvents in a wide range of analyses and test equipment. As such, the ability of seals to resist a breadth of chemicals without degradation or leaching contaminants into a sample is of great importance. Although instrument seals are easily replaced in a laboratory environment, this operation still takes a technician time. It is always easier if the system can be flushed with a cleaning solvent and then be ready to run the next sample versus having to change out an elastomer seal due to incompatibility with a solvent.
Gallagher recently released our High Performance Elastomer Seals for the Instrumentation Industry White Paper. This was written by Russ Schnell, an Elastomer Consultant contracted by Gallagher Fluid Seals, and a former Senior Application Engineer with the Kalrez® perfluoroelastomer parts business at DuPont. This white paper is now available for download on our Resources page.
Below is the first section of the white paper, diving into applications where the measurement is made at the process and the results then transmitted to a control system. This section will review the four types of in-line measurement devices, all involving slightly different elastomer sealing applications.
Flowmeters are used to measure the flow of liquid. In this section we will only consider the measurement of liquid flow in a closed piping system. Several examples of flow measurement devices include: flowmeters, Venturi tubes and orifice plates.
Note that these devices are “in-line” and require isolating the process line to remove and repair, or replace the measurement device. Shutting down a process to remove a device is time consuming, involves loss of production, and may require specific procedures to protect the operators and environment when a line is opened. All of these devices require seals to prevent leakage of the process to the environment and the elastomer seals should last the life of the flowmeter. For aggressive chemicals or high temperature applications, FKM or FFKM seals are an excellent choice. These products offer a long service life and resist deterioration in harsh environments.
Gallagher recently released our High Performance Elastomer Seals for the Instrumentation Industry White Paper, available for download on our site. This was written by Russ Schnell, an Elastomer Consultant contracted by Gallagher Fluid Seals, and a former Senior Application Engineer with the Kalrez® perfluoroelastomer parts business at DuPont. This white paper is now available for download on our Resources page.
The term instrumentation covers a wide variety of applications. In the broadest sense, instrumentation may be considered as any equipment used for measurements. This equipment may be in a process stream and include devices such as flowmeters, pressure gages, and inline probes. Data from these devices are used for process control. In automobiles, sensors are used for a variety of applications including measuring the exhaust stream to “tune” the engine to yield maximum performance. Analytical laboratory instruments such as chromatographs and flame ionization detectors are used to determine the composition of samples. Instruments are used in the medical industry for product analysis as well as analysis of blood and urine samples. Of course this is only a partial list of the many applications involving instruments.
Gallagher Fluid Seals recently made our Fluoroelastomer Basics webinar available on the website.
This webinar will discuss:
An elastomer is made up of long chain polymers which are connected by crosslinks. Crosslinks are analogous to springs and provide an "elastic" (recovery) nature to the material. The crosslinks are relatively stable, but can break down under extreme temperatures and pressures.
Gallagher recently released our Introduction to Perfluoroelastomers White Paper, available for download on our site. This was written by Russell Schnell, a current contracted employee of Gallagher Fluid Seals, and more importantly, a former Senior Application Engineer with the Kalrez® perfluoroelastomer parts business at DuPont. The following is the third and final excerpt from the White Paper, discussing seal design and a cost-benefit analysis of using perfluoroelastomer seals.
Seal Design with Perfluoroelastomer Seals
Care must be taken when designing and using seals made of perfluoroelastomers. These elastomers typically have a higher coefficient of thermal expansion when compared to other elastomers; plus, they are often used at higher temperatures. If the seal gland design is not correct, seal extrusion will occur, resulting in seal failure. For example, a fluoroelastomer seal is scheduled for replacement with a perfluoroelastomer seal, due to high application temperatures. Shortly after this substitution, the FFKM seal fails due to extrusion. The probable cause is that the seal gland volume was too small to accommodate the thermal expansion of the high performance perfluoroelastomers, a factor that many of today’s seal design handbooks do not adequately take into account.
The spectrum of elastomers range from very simple forms, like the natural rubber already in use in the 19th century, to modern, high performance elastomers from the second half of the 20th century. They are continually being improved.
This blog article is the second in a two-part series discussing the many different elastomer materials available today, as discussed in Freudenberg's The World of Freudenberg Sealing Technologies.
The first post discussed Natural Rubber (NR), Nitrile Rubber (NBR), and Hydrogenated Nitrile Rubber (HNBR).
Polyacrylate Rubber (ACM)
ACM elastomers are made of polar acrylic acids. As polar materials, they display good resistance to high-additive lubricating oils. Due to its saturated¹ main chain, the material exhibits good resistance to ozone, weather and heated air. Petroleum-based oils and fluids (for engines, transmissions and automatic transmissions) cannot harm them. But the material offers only moderate strength and low elasticity while displaying limited cold behavior.