The right mixture does the trick – even for seals used in hydraulic cylinders. But the optimal interplay of the individual seals is a delicate matter. To save its customers a great deal of time and effort, Freudenberg Sealing Technologies (FST) has developed five preassembled sealing systems. They contain all the components needed for specific customer applications.
Until now, it took extensive experience and even more stamina to assemble a sealing package for hydraulic cylinders. To start with, the selection is huge: The FST catalog offers well more than 100 different rod and piston seals as well as wipers. Moreover, the individual seals have to function in combination, ideally supporting and complementing one another. Due to this mutual influence, every change has an effect on the functionality and performance of neighboring components. The approach to the result is gradual and cautious.
SIMPLER, FASTER, INTEGRATED…
An Entire Solution in a Single Package
Freudenberg takes the customer out of the complex, tedious process of selection, adjustment and modification, providing integral sealing systems. The company has developed so-called ‘application cards’ that specific dedicated sealing systems for selected market segments and their applications. Here FST has gone beyond what is normal among its competitors. It doesn’t merely provide a fraction of all the components needed for hydraulic cylinders – it delivers all of them, from piston guides and seals, to primary and secondary rod seals, all the way to rod guides and wipers – and considers all their interactions in the process. As a result, a specialized knowledge of individual sealing elements is no longer needed. Continue reading Sealing Systems for Hydraulic Cylinders→
Freudenberg Sealing Technologies has introduced a new generation of polyurethane for seals that set new standards. Freudenberg’s development of its own materials is an important core competency. The company has succeeded in manufacturing a basic material for seals with a far longer operating life than the polyurethane materials used so far.
Watch the video below to see how the seals of today are fulfilling the requirements of tomorrow.
The Freudenberg Simmerring has been a successful product for about 85 years. It seals rotating shafts reliably, and is used in millions of applications and machines in many industries. The Simmerring is flexible, highly loadable, and very dependable. Freudenberg Sealing Technologies has now further developed Simmerrings for use in the process industry – and they are made of food-grade materials.
At high rotational speeds and pressures, traditional PTFE shaft seal rings quickly reach their limits. Seal malfunctions and leaks are the result. Moreover, it has not been possible to use Simmerrings in the food industry to this point because their PTFE materials have not been approved for food-related applications. That’s why experts at Freudenberg Sealing Technologies have developed two new materials – from which tried-and-tested Simmerrings are manufactured – especially to meet the process industry’s requirements.
Maximum Performance even under Extreme Pressure: B2PT
Simmerrings with the B2PT design can be stressed with pressures of up to 10 bar. The B2PT consists of a newly developed material, Quantum® PTFE F18245, and a housing made of 1.4571 (V4a) stainless steel. The PTFE used here has been conceived especially for direct contact with foods. The still-required approvals under FDA 21 CFR §177.1550 und EC 10/2011 are in preparation. This Simmerring design is thus superbly suited for the food and pharmaceutical industries. The design of the B2PT can also be adapted for customer-specific, individualized applications.
Small, nondescript and ostensibly unspectacular – it is often developments of this exact description that lead to groundbreaking innovations in the world of technology. The idea of manufacturing seal sleeves from leather scraps became the starting point in one of the most important developments in sealing technology: the Simmerring®. For 85 years, the Simmerring has been inseparable from the Freudenberg history of success, and, in Europe, its name has even become a synonym for (radial) shaft seal rings of every kind. Today the Simmerring is a high-tech product whose key functions go far beyond the sealing of the shaft against its housing.
It all started with the economic crisis of 1929, which plunged the leather industry and thus the Freudenberg tannery – which was founded in 1849 – into difficulties. To better distribute its risks in the future, Freudenberg began to diversify the company and serve a broader market. A sample of a leather sleeve from the United States was the inspiration for giving Walther Simmer and his team the job of developing a machine that could be used to produce lip seals made of leather scraps.
Seals are increasingly being asked to do more than just seal. In the future, they should be able to forecast when they will break down and perform condition monitoring in real time – all on their own. As a technology specialist, Freudenberg Sealing Technologies is not just anticipating the steadily rising demands on seals but on future sealing materials as well. At Drinktec 2017 in Munich (Germany), the company presented a new generation of smart seals that is becoming possible for the food and process industries, thanks to a combination of various material characteristics.
Seals primarily consist of materials that cannot process signals in their pure form. That’s why Freudenberg Sealing Technologies’ material developers are investigating materials that seals can employ to become sensors or even actuators, for example, without impairing their original mission.
What do you do when you need an urgent spare part for a made-to-order seal? What do you do when special seals are required for a short production run of 400 machines? It’s hard to know. Here’s where the Freudenberg Xpress® experts come into play.
Timo Furrer oversees Freudenberg Xpress, which now includes 12 facilities worldwide. He and his team are in demand whenever time is pressing or the manufacture of prototypes or short production runs is required. “Customers traditionally turn to us when they need a specific sealing solution fast for maintenance and repair work,” Furrer said. But there are other occasions as well. Freudenberg Xpress experts are also called on when a manufacturer develops new equipment and has to find the best possible sealing systems for it. To avoid costly field tests, the manufacturer tests the limits of various prototypes that Freudenberg Xpress can provide on short notice.
From Tiny to Huge
To these sealing specialists, it doesn’t matter whether their customers need seals with diameters of just two millimeters or a full twenty meters – a size that can be found in wind turbines or hydro-electric plants. Nor does it matter whether the order is for a standard seal or a customer-specific product. “Within 24 hours of the incoming order’s arrival, we can produce and deliver up to 50 units,” Furrer said.
Lightweight design has recently become a much more significant trend in the auto industry. Even with small components like seals, a great deal of weight can be saved. From Freudenberg’s standpoint, several forward-looking issues come together in these approaches.
In his office, Dr. Ted Duclos, the CTO of Freudenberg Sealing Technologies, is holding up a palm-sized plastic ring. “I know that it seems very small and insignificant,” he said. “But components like this quickly add up to several kilograms of weight in an engine.” And weight is one of the factors getting special attention from the auto industry – for a range of very different reasons.
Duclos has just returned from the Lightweight Summit in Würzburg, an international gathering of more than 300 experts from industry and research. Specialized lectures, discussion panels and presentations focus on lightweight design in the auto industry and especially in electric mobility. “Lightweight design is a trend,” Duclos said. In the design of classic internal combustion engines because low weight reduces emissions. And for the future of the electric car because reduced weight increases the vehicle’s range. Or to put it another way, lightweight design is one of several trends that are now logically tied to one another.
Polytetrafluoroethylene (PTFE) is commonly known as a coating for pans under the DuPont trade name Teflon™. It is also superbly suited as a sealant and is superior to many materials in specific ways. For example, it can be used at low and high temperatures and in combination with gasoline, solvents, water and other polar media such as lyes, standard lubricants and brake fluid. PTFE’s chemical resistance is nearly universal.
In 1938, while working for DuPont, American chemist Roy Plunkett was looking for a substitute for the fluorohydrocarbon Freon, which his employer was only allowed to sell to General Motors’ Frigidaire division for patent-related reasons. For his research, he had obtained a supply of tetrafluoroethylene (TFE), which was used as refrigerator coolant. He stored it in small pressurized gas cylinders at low temperatures. When he was ready to use the gas after a fairly long storage period, none was left in the container. But its weight was unchanged. After it was opened, there were white crumbs inside and the inner walls of the container were covered with a thin layer. Plunkett quickly realized that the TFE gas had been polymerized into a plastic. This new plastic, PTFE, proved to be completely resistant to chemical exposure. Not even aqua regia¹ could harm it in any way. But its production was so costly that practical uses seemed inconceivable.
Anyone who has ever enjoyed a fruit tea out of a mug that previously contained coffee knows the problem: taste transfer. It is an undesirable phenomenon during product changeovers in the food industry.
With Fluoroprene XP, a line of premium seal materials, Freudenberg has brought out an all-purpose weapon to handle steam sterilization, aggressive media used for cleaning in place (CIP) and sterilization in place (SIP), and high-fat concentrations. Until now, production processes in the food industry, in particular, have required the use of an extremely wide range of material options. Depending on the fat, flavor or acid concentrations in the food, and the specifications of the CIP/SIP processes and steam sterilization, seals made from EPDM, VMQ or FKM are used.
Thanks to their high elasticity and their very good resistance to wear and abrasion, elastomers made of rubber are generally superbly suited to seals. But they also have disadvantages: Due to their limited Shore hardness (a maximum of 90 SH A), they are not suited to applications at all levels of pressure. Dynamic applications are only achievable with the use of lubricants. Freudenberg Sealing Technologies polyurethane materials offer an alternative in cases where rubber elastomers cannot be used or where highly specialized elastomers are out of the question for cost-related reasons.
In 1937, a research group at I.G. Farben led by Dr. Otto Bayer (1902–1982) produced polyurethane (PU) synthetically for the first time, and the material made its triumphant march around the world. The industrial production of PU began in 1940. The first foam material based on PU was developed between 1952 and 1954. Many additional developments based on PU followed over the course of decades. As early as 1960, the production of PU foam material came to 45,000 tons. Global demand has greatly increased since then. At present, more than 12 million tons are processed annually. Today it is difficult to imagine our everyday lives without polyurethanes. They are actually one of the most multifaceted categories of plastic. We encounter them as soft polyester foams, as thermal insulating materials, in the soles of our shoes and in the steering wheels of our cars. Polyurethanes above all owe their wide distribution to two special attributes: They can be produced by mixing liquid feed materials. This can even be done in small processing operations. And since innumerable feed materials are available, it is possible to manufacture made-to-order materials in consistencies ranging from soft to hard or from foamed to compact, for a broad range of applications.