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|Legal form||Gesellschaft mit beschränkter Haftung|
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|Kompass member for||+ 3 years|
Presentation - Trelleborg Sealing Solutions Germany GmbH
Our customers come from all corners of the industry, including service and maintenance/repair, manufacturing and wholesale distribution. Our products are specifically intended to suit a variety of hydraulic applications, from light-duty linear hydraulic to heavy-duty rotary seals and static applications.
Our broad and diversified product range sets us apart from the rest, notably our extensive selection of FKM seals. On top of everything, all products are immediately available from stock (unless otherwise stated).
News - Trelleborg Sealing Solutions Germany GmbH
Oct 17 2019Product Article
Plunger Cylinders in Forklift TrucksAbout the Mobile Hydraulic Equipment Sector
From pumps and valves to cylinders, mobile hydraulics have become an integral part of our daily lives and find applications in many different industrial areas. Often taken for granted, these devices provide the power to lift heavy loads, exert high forces for clamping or pressing and to accurately position a wide range of mechanical arms.
Mobile hydraulics are one of the most important components of forklift trucks. These vehicles are regularly used, which means that the truck and its many pieces need constant maintenance and repair, which can greatly affect efficiency of the machine.
In the following example, we will focus on the maintenance of a plunger cylinder in forklift trucks assumed to be operating in temperatures ranging from -10°C to 95°C.
Maintenance of a Forklift Plunger Cylinder
The plunger cylinder is a single-acting cylinder used for lifting. It is installed in an upright position such that when the control valve is switched to the lowering position, the weight of the carriage (with or without a load) forces the fluid back through the return lines, allowing for smooth lowering.
Once a forklift plunger cylinder needs to be replaced, our recommended solution for the rod seals is a polyurethane primary seal, a high-strength nylon wear ring, and a polyurethane scraper seal. The combination of Zurcon® Rimseal, Himod® Slydring® and Zurcon® Scraper DA22 provides an economical, high-performance sealing solution for this type of hydraulic cylinder. If you require a smaller rod seal, you could also use the Zurcon® U-Cup RU9 instead of the Rimseal.
Since it is not always possible to have replacement parts in stock and they may not be immediately available for delivery, as Trelleborg Sealing Solutions online shop, we offer all the above-mentioned parts in a range of different diameters to suit your specific needs, and so minimizing downtime. Our replacement parts are ready for immediate shipping to help make maintenance and repair even easier and faster. For more information, visit our product pages.
Please note, recommendations on application and system design are provided as suggestions only. It is the customer’s responsibility to ensure safe and adequate performance in their own application. Seals-Shop or its supply partners cannot accept liability for the form, fit, or function sold through the Seals-Shop or consequential damages thereafter.Show More Show less
Apr 9 2019Product Article
Forklift Mast CylindersMobile hydraulics are one of the main components found in forklift trucks, providing the power to maneuver the forks, for example. These vehicles have become indispensable in a number of working environments, as they are particularly useful in both the areas of manufacturing and logistics, ensuring items are in the right place at the right time.
As a result, these trucks are often in constant use, meaning that the vehicle and its many sub-systems require regular maintenance and repair, which can have a large impact on productivity. While this can be done in house by the forklift owner, the replacement parts need not be ready to use immediately, and it may not always be possible to keep parts in stock. Seals-Shop.com offers many proven products for such sealing solutions, ready for immediate shipping, to help make maintenance and repair easier and faster. Keeping downtime to a minimum.
In the following example, we will focus on the maintenance of a forklift mast cylinder assumed to be operating in temperatures ranging from -10°C to 95°C.
Maintenance of a Forklift Mast Cylinder
The lift or mast cylinder is an essential part of the forklift, controlling the vertical assembly on the front that allows the truck to fulfil its main function: raising and lowering the load in question. As such, these cylinders are subjected the largest volume of fluid flow.
When this hydraulic cylinder needs to be repaired, it is recommended that a polyurethane u-cup is used as a primary seal, together with a high-strength nylon wear ring as a guiding element, together with a polyurethane wiper seal to achieve an optimum cost-performance ratio. A combination of the RU9 U-Cup, Himod® Slydring®, and Zurcon® Scraper DA22 make for an ideal configuration.
All these hydraulic seals and many more are available in Trelleborg’s Seals-Shop in a range of sizes and can be shipped in a couple of days within Europe. For more information, visit Seals-Shop.com.
Please note, recommendations on application and system design are provided as suggestions only. It is the customer’s responsibility to ensure safe and adequate performance in their own application. Seals-Shop or its supply partners cannot accept liability for the form, fit, or function sold through the Seals-Shop or consequential damages thereafter.Show More Show less
Mar 5 2019Product Article
Avoid Seal DamageCritical to the function of just about any hydraulic application is the seal. Hydraulic seals serve a number of functions, the most important of which involves preventing fluid leakage while withstanding temperature extremes, high pressures and transverse forces.
Hydraulic seals include piston seals, rod seals, wear rings, scrapers, o-rings, quad-rings, static seals and rotary seals.
- The purpose of the piston seal is to seal in fluid, halting its flow to the piston. This results in the build-up of pressure on one of the piston’s sides.
- Rod seals are the external seals that halt cylinder leakage.
- Wear rings serve to guide both the piston rod and the piston in the cylinder, thereby eliminating metal-on-metal contact.
- The purpose of the scraper is to prohibit cylinder damage by denying access to dangerous contaminants.
- Considered one of the most widely used seals, O-rings are appropriate for both dynamic and static applications, sealing all media.
- Quad-rings are often considered a variation on the traditional O-ring. With its X-shaped cross section, this seal is ideal for both static and dynamic applications.
- Static seals are ideal for sealing applications that do not require movement between sealing surfaces.
- Rotary seals, on the other hand, are used in applications where components are rotating or oscillating.
A breakdown in of any of these units will culminate in inevitable harm to machinery.
Considering the toll on hydraulic seals in hydraulic applications, avoiding hydraulic seal damage becomes a critical matter of selecting the right seal for the right application.
Found in applications ranging from off-highway vehicles, machine tools, trucks and injection molding machines, hydraulic seals need to fit the application and environment for their intended uses.
Here are considerations for making such a determination and, consequently, avoiding hydraulic seal damage.
Different pressure demands will govern different applications. In order to select the right seal, the pressure limit of the application needs to be evident. When considering the pressure needs of the machinery, the first factor to consider is the megapascal (MPa) pressure unit necessary.
Without reliable, quality parts, the cylinder will only be capable of inferior performance, not to mention a shorter service life. That is why hardware is critical to the function of hydraulic systems. A good rule of thumb in selecting a seal is to remember that the better the hardware, the better the seal.
Component design will significantly affect the selection of seals. Governing those design decisions are considerations such as necessary speed, efficiency and compliance with standards and reliability. Knowledge of the installation dimensions also informs the seal selection process.
Some questions to ask when making a seal selection with the goal of avoiding future seal damage:
- Can the seals combat contamination?
- Are the seals low-friction?
- Can the seals be assembled with ease?
- Will the seals be easy to maintain?
- How will the seals perform against temperature extremes and media?
- Are the seals compliant with industry standards?
Seals-Shop, with its variety of seals made from high-quality materials such as Zurcon® or Turcon®, can help make the right seal selection. Seals-Shop offers a variety of hydraulic seals that are durable and that rely on only a minimal amount of maintenance. Additionally, because the seals are compact, they can be installed with ease.
Let Seals-Shop help find the ideal seal for any application using their convenient Product Finder. Need installation help? Each Seals-Shop product description includes an easy-to-follow diagram detailing the installation steps for each specific seal — just another way that Seals-Shop helps to avoid costly seal damage.
Seals-Shop, the official online shop of Trelleborg Sealing Solutions, offers a wide range of hydraulic, pneumatic and mechanical sealing products for a variety of applications. For more information, visit Seals-Shop.com.Show More Show less
Jan 29 2019Product Article
How to Convert Imperial Units of O-Rings to Metric SizesO-rings are the most widely used seals because they are efficient, economical, and can be used in a wide variety of static and dynamic applications. In order to get the most out of an O-ring, it is critical that its dimensions and specifications meet part requirements.
Sometimes, this can be difficult if a part is metric and the only available seals have Imperial units dimensions, or vice versa. Still, this is not an insurmountable obstacle if an engineer knows the conversions involved. Here are some common seal units and the conversions between metric and imperial units for them.
There are several specifications that are essential to selecting the correct O-ring. The inside diameter, outside diameter and cross section define the dimensions of an O-ring. The inside and outside diameters are the distances from the center to the O-ring’s inside and outside surfaces, respectively. The cross section is the difference between the outer and inner diameters. All three dimensions are typically given in millimeters (mm) for metric O-rings and inches (in) for imperial O-rings.
One inch is equal to 25.4 mm, so when converting from an imperial dimension to a metric dimension, simply multiply by 25.4 mm/in. In order to convert from metric to imperial dimensions, multiply by the inverse of 25.4 mm/in, which is approximately 0.0394 in/mm. Imperial specifications are sometimes given as fractions (such as 1/3”) where the quote symbol after the fraction represents the imperial unit inch. In these cases, the first step is to always convert the fraction to a decimal, then perform the unit conversion. Thus, for example, 1/3” = ~0.33 in = 0.33 in x 25.4 mm/in = ~8.5 mm.
Another important O-ring specification is the maximum pressure rating. Generally, this tends to be expressed in megapascals (MPa) for metric O-rings. Imperial O-rings usually express this specification in units of pound-force per square inch (psi). One MPa is equal to approximately 145 psi. Therefore, to convert the required maximum pressure for an O-ring to imperial units, multiply by 145 psi/MPa. To convert an imperial maximum pressure to MPa, multiply by the inverse, equal to ~.007 MPa/psi. Occasionally, rather than MPa, maximum pressure will be given in bar. A bar is simply one-tenth of an MPa, so the conversion here is simple: 1 bar = 0.1 MPa = 14.5 psi.
Operating temperature range is another important specification that helps one understand whether an O-ring can withstand the environmental challenges of its application. It is therefore very important that a conversion is done correctly when comparing metric and imperial units. Metric O-rings have temperature ranges given in degrees Celsius. Imperial O-rings have operating temperature ranges given in degrees Fahrenheit.
To convert from Celsius to Fahrenheit, use the following formula:
T(°F) = T(°C) × 1.8 + 32
To convert from Fahrenheit to Celsius, use the following formula:
T(°C) = (T(°F) - 32) / 1.8
The specifications of inner diameter, outer diameter, cross section, maximum pressure and operating temperature range are critical to accurately identifying the correct O-ring for an application. Consequently, it is imperative, when confronted by metric or imperial units for these O-rings or their applications, that an engineer is able to convert between the two-unit systems for those specifications. Although the metric and imperial units don’t have to exactly agree, it is a good idea to try to get them as close as possible for optimal O-ring performance and part life.
Seals-Shop, the online shop of Trelleborg Sealing Solutions, offers a wide number of hydraulic, pneumatic and mechanical sealing products for a variety of applications available for immediate shipment in most cases. For more information, visit Seals-Shop.com.Show More Show less
Jan 8 2019Product Article
The correct selection of Radial Oil SealsSimply put, the function of seals is to minimize or prevent leakage between two parts. While seals provide this very basic role, choosing the right seal for the job takes real consideration and knowledge. Selection also assumes that the seal purchaser grasps the potential effects of the environment on the seal in addition to understanding the machine or equipment where the seal will reside. In this case, for radial oil seals.
Choosing the right radial oil seal for virtually any application depends on operating conditions and the physical dimensions of the seal itself. While there are many considerations, here is a breakdown of the top four things you need to know when selecting a seal and why each is important.
The temperature within the seal’s environment is the main factor that dictates the radial oil seal materials. There is generally a stated temperature range that is optimal for that particular rotary seal. For example, there may be a stated range of 4 to 49° C. When the operating environment is too cold a seal may become brittle and at high temperatures the seal material may show greater elasticity. Increased temperature also accelerates the aging of the rubber. When axial cracks at the sealing edge are visible, the radial oil seal has been exposed to excessively high temperature, clearly out of its recommended range. An ambient air temperature increase of 10° C can halve the theoretical useful life of the rubber.
It isn’t just air temperature that can affect seals. Temperatures can fluctuate from:
- High-speed rotation that generates excess heat
- Insufficient lubricating and thermal management capabilities of the lubricant
- The circumferential velocity
- Applied pressure
Position or Size
Measurement is a key element for proper radial oil seal selection. The groove or the position into which the seal will be housed must be measured correctly so that there is as perfect fit as possible. This is critical because if your rotary seal does not fit, it will not be viable and leakage or contamination is a certainty.
Seal size is determined by the seal bore, the diameter of the hole in the housing where the seal will be fitted, seal outer and inner diameters (OD and ID) and seal width, which is the total width of the seal including inner and outer shells.
- Seal bore represents the diameter of the hole into which the radial oil seal will be seated.
- Seal OD: Measurements should be taken in at least three places equally spaced around the radial oil seal. The average of these readings can then be used as the OD.
- Seal width is a measurement of the radial oil seal height when laid on a level surface, which includes inner and outer shells.
- Shaft ID: A radial oil seal’s inner diameter can vary, so the shaft diameter is used as the inside dimension. If you don’t know the actual shaft diameter, you can estimate it by measuring the seal’s inside dimensions.
As the amount of pressure grows, the radial load and friction of the sealing lip increases as it contacts the shaft. Like temperature, recommended pressure for optimum performance is spelled out for each radial oil seal. Excess pressure causes seals to wear faster and shortens their life.
When a seal is under too much pressure, specified values of peripheral speed cannot be maintained but must be lowered relative to the magnitude of the pressure. At high pressures leakage between the seal’s periphery and the housing bore can be avoided by using radial oil seals with rubber-covered cases. When a seal is under pressure there is also a risk of axial movement in the housing bore, which is prevented by locating the seal against a shoulder with a spacer ring.
The speed at which a radial oil seal can effectively operate depends on such conditions as pressure, temperature, the lubricant or fluid involved, shaft finish and seal design. Lubrication between the seal lip and a moving surface reduces friction, an important seal degradant. The thickness of the lubricating film establishes the level of friction. Initially, when velocity increases, friction decreases as the lubricant is dispersed. Even at increased velocity, frictional forces will begin to climb, causing wear.
Various seal designs allow for a variety of maximum peripheral speeds. Higher peripheral speeds are appropriate for larger shaft diameters more than for smaller diameters, as cross-sectional area increases in proportion to the square of the diameter, thus increasing the heat dissipation capacity.
While higher speeds affect performance and seal life, speeds under and over the recommended range cause increased friction, impacting the seal material.
Common Causes of Radial Oil Seal Failure
While all seals eventually wear out, the most common causes of rapid failure include:
- Installation — damaged by handling, incorrect measurement, etc.
- Seal face open during operation, enabling particles to penetrate and affect seal fastening
- Improper radial oil seal selection
- Poor design
- Inadequate environmental controls
Not often considered is the chemical composition of the radial oil seal components, corrosion resistance, effects of compression, chemical attack, material choice and changing ambient conditions during use.
Today, there are interactive tools such as a Fits & Tolerances Calculator that allows you to determine lower and upper limit deviations and maximum and minimum interferences based on the selected tolerance classes for seal bore and shaft, which helps with the selection of the right radial oil seal.
The information in this article should provide the basics of selection. In addition, should a radial oil seal fail, look at the evidence, which should lead to the reason for the failure. Is the seal brittle or too elastic? The issue is temperature. Are particles getting through the seal? Check the rotary seal face opening.
Finding the best seal for your application does not need to be a larger-than-life exercise. For that best seal, begin here or try our Product Finder.Show More Show less
Nov 12 2018Product Article
Single-acting vs. Double-acting Piston SealsWithout the proper seal, the failure of a hydraulic cylinder, and thus the entire hydraulic system, is all but guaranteed.
As such, it is critical to make sure that the right seal is selected based on factors such as how the cylinder is expected to operate as the piston is pushed down the cylinder bore.
As a necessary component of fluid sealing in hydraulic cylinders, piston seals, also known as piston rings, are designed to seal in fluid, thus preventing the flow of fluid across the piston. This is made possible when the piston seal secures against the cylinder bore from inside the hydraulic cylinder, meaning that pressure will build up on one side of the piston.
Yet, because hydraulic cylinder seals are found in everything from machine tools, trucks and off-highway vehicles to injection mold machines, it stands to reason that a seal will sometimes need to conceal pressure from both sides of the piston.
This demonstrates a scenario where the choice between single-acting hydraulic seals versus double-acting hydraulic seals becomes crucial.
Single-acting vs. Double-acting Piston Seals
Single-acting piston seals are designed to keep pressure on one side of the piston without leakage. Because the seal operates in one direction (unidirectional), the pressure is applied on one side only.
Double-acting piston seals, on the other hand, are designed to conceal pressure from both sides, which means that they are designed to be bidirectional.
Selecting between single-acting and double-acting piston seals has everything to do with the intended use of the system and the direction that the system will be operating in. As such, choosing wisely can make all the difference in the life of a cylinder and thus help avoid unwanted machine downtime.
Helping to make that decision easier is Seals-Shop, with a variety of Trelleborg piston seals to fit just about any application. Made from high-quality materials that are durable in most conditions, Trelleborg seals have the answer to just about any question concerning hydraulic, pneumatic and mechanical seals and, as its online shop, Seals-Shop will help find the ideal seal for any application using their convenient Product Finder. Need installation help? Each product description on Seals-Shop.com includes an easy-to-follow diagram detailing the installation steps for each specific seal. For more information, visit Seals-Shop.com.Show More Show less
Oct 2 2018Product article
O-ring sizes for hydraulic sealsAn O-ring is a loop of elastomer with a round cross-section designed to be seated in a groove/gland and compressed during assembly, creating a seal between two or more parts. O-rings cover a wide range of applications and are used in all industries, for both the maintenance of older products and for new product designs. The relatively low-production costs and ease of installation and use have made the O-ring the most widely used seal. Practically all liquid and gaseous media can be sealed using one of the many elastomeric O-rings available.
O-rings are particularly well-suited for hydraulics, both for maintenance and new applications. They seal over a wide range of pressures, temperatures and tolerances, require very little space and are lightweight and sometimes reusable. They come in many sizes and materials, often specialized for particular applications. O-rings are particularly important for hydraulic systems since they seal connections by being forced into a channel and held in place by hydraulic pressure. The O-ring is used to prevent leakage and prevent outside contaminants from penetrating the hydraulic system. Following is a breakdown of some specifications, materials and features of O-rings for hydraulics.
There are several essential specifications for selecting the correct O-rings in hydraulic systems. The inside diameter, outside diameter and cross section define the dimensions of an O-ring. The inside and outside diameters are the distances from the center to the O-ring’s inside and outside surface respectively. The cross section is the difference between the outer and inner diameters. O-ring inside diameters and outside diameters can vary significantly, from a few millimeters to a meter or more. Be sure to leave some space when specifying O-ring inside diameter to account for swelling and possible thermal expansion.
Avoid stretching the O-ring more than five percent, if possible, as stretching can cause the cross section of the O-ring to flatten. O-ring cross sections tend to vary less, from a few millimeters to tens of millimeters. When selecting an O-ring for your hydraulic application, it is very important to know the depth of the gland so that the O-ring selected has the appropriate cross section to avoid extrusion and tearing and to ensure a proper seal.
O-rings come in a variety of materials, including nitrile rubber (NBR), ethylene propylene diene rubber (EPDM), fluoroelastomers (FKM) such as Viton®, silicone rubber (VMQ) and others. NBR has excellent resistance to hydraulic fluids and can be used in the temperature range of -35° C to +120° C. NBR is a copolymer of butadiene and acrylonitrile that becomes more resistant to hydraulic fluids as its nitrile component increases, but it also becomes less flexible. Although NBR does not possess good resistance to ozone, sunlight or weather, it has excellent resistance to compression set, tear and abrasion. O-rings made of NBR generally are an excellent choice for hydraulic applications.
EPDM O-rings have excellent resistance to heat, water, steam, ozone and sunlight. EPDM O-rings are particularly useful when sealing phosphate-ester hydraulic fluids and may be appropriate for some applications in place of NBR. FKM (Viton®) O-rings have very high resistance to high temperatures, greases, fuels, silicone oils and many other materials and are well-suited for aerospace applications. Increasing fluorine content in FKM increases chemical resistance while low-temperature characteristics regress. FKM can be used with non-flammable hydraulic fluids and may be an appropriate choice for hydraulic applications under certain circumstances. Finally, VMQ has good ozone and weather resistance as well as good cold flexibility and high heat resistance, though it is susceptible to superheated steam. VMQ O-rings have relatively low tensile and tear strength and are susceptible to wear. Although excellent for many applications, VMQ is not usually used for hydraulic O-rings.
Another set of important O-ring specifications are the maximum pressure and the operating temperature range.
Generally, maximum pressure tends to be expressed in megapascals (MPa) and operating temperature range is expressed in degrees Celsius. Depending on the O-ring material, maximum pressure can be as high as 25 MPa and operating temperature ranges can vary from -40° C to +200° C. It is very important when selecting an O-ring that the maximum pressure and operating temperature range encompass the extremes of the O-ring application. O-ring chemical resistance, flexibility, tear resistance, abrasion resistance, weather resistance and other properties can be compromised if an O-ring is exposed to conditions beyond its maximum pressure or operating temperature range.
Some applications involving pressures greater than 5 MPa may be ideal for a backup ring. When internal pressure becomes too high, an O-ring may extrude and quickly lose material through wear. Seal failure usually follows fairly quickly afterward. A backup ring is a ring of hard, extrusion resistant material that fits between the O-ring and extrusion gap, thus preventing O-ring extrusion. This can be a cost-effective alternative to more durable yet more expensive materials. An alternative to O-rings that can also be used with backup rings is the X-ring, or Quad-Ring®. Quad-Rings® have two sealing areas per side as opposed to the one for O-rings. As a consequence, Quad-Rings® require less deformation to maintain an effective seal. Less deformation means less friction and wear, which gives Quad-Rings® a longer seal life compared to O-rings. Quad-Rings® come in a variety of materials and sizes and can be an alternative to O-rings for hydraulic system sealing.
The specifications of inner diameter, outer diameter, cross section, material, maximum pressure and operating temperature range are critical to identifying the correct O-ring for your hydraulic application. Backup rings can help prevent extrusion in high-pressure applications while quad-rings offer a longer-life alternative to O-rings for particular applications. Although O-rings are usually a very small and inexpensive part of your hydraulic system, they can be critical to its performance and are worth researching and understanding so that the correct O-ring (or Quad-Rings®) is selected and installed. Putting in the time to understand the O-ring that you need now may buy you years of operation for your hydraulic system. If you are unsure of the article number of your seal, product finders or some online-shops (such as seals-shop.com) quite often have the option to search by the aforementioned criteria when applying filters during product selection.Show More Show less
Aug 30 2018Product article
How To Prevent Hydraulic LeaksConsidering that a seal failure in almost any number of hydraulic system applications will generally result in total machine failure, sealing a hydraulic cylinder is a critical matter.
When replacing a failing seal it is important to make sure that certain critical factors are considered before making a selection. To make the right selection, it is important to first understand how a hydraulic cylinder is sealed.
Particularly challenging for seals are hydraulic applications where fluid must be kept from leaking from a cylinder. Add to that the high pressures, transverse forces and extreme temperatures within the cylinder, and the challenge is amplified. As such, preventing leaks becomes only one of several concerns surrounding hydraulic seals.
Hydraulic cylinder seals, found in everything from machine tools, trucks, off-highway vehicles and injection mold machines, serve a variety of functions. Most critically, this includes closing a gap, making sure that the system is leak-tight and capable of transferring forces within the system.
To ensure the long lifetime and low maintenance of a hydraulic system, it is vital to consider the hydraulic seals that are best suited to help protect the cylinder from damage.
Hydraulic sealing systems can include:
- Piston seals, which work to seal in fluid, thus preventing the flow of fluid across the piston, allowing pressure to build up on one side of the piston.
- Rod seals, which are external seals that prevent leakage from the cylinder.
- Wear rings, which guide the piston and piston rod in the cylinder and prevent metal on metal contact.
- Scrapers, which prevent damage to the cylinder by sweeping away dangerous contaminants.
As such, it is important to consider pressure, hardware and design requirements of a hydraulic seal when making a selection.
Different applications will have different pressure requirements. When considering pressure limits of the application, first consider the required megapascal (MPa) pressure unit.
Hardware is also a crucial consideration for hydraulic systems. Without quality hardware, the cylinder will only offer sub-par system performance and abbreviated service life.
Design considerations will greatly impact seal selection, and these considerations are dictated by factors such as required speed, efficiency, compliance with standards and reliability. To determine what seal is necessary for what application, ask the following questions when making a selection:
- Will the seals resist abrasive particles?
- Are the seals low-friction?
- Are the seals easy to assemble and maintain?
- Are the seals stable against temperature and media?
- Do the seals comply with industry standards?
- Are reliable replacement parts available for the seals, even for minimum quantities?
Seals-Shop, a partner and provider of Trelleborg Sealing Solutions products, offers many hydraulic, pneumatic and mechanical sealing solutions for a variety of applications, whether new or for maintenance. For more information, visit Seals-Shop.com.Show More Show less
May 7 2018Product article
How To Prevent Seal FailureThe two main functions of a seal are to minimize or prevent leakage of fluid while keeping dirt and debris out. If a seal is not made as per functional requirements, or is installed and maintained improperly, it may fail and cause a loss of fluid.
To function properly seals must withstand extreme temperatures, high pressures, chemicals and contaminants. Seals can be composed of a number of different materials, and choosing the right seal for the job is not a trivial task; it takes consideration and knowledge of not only the machine or equipment that the seal will reside on or in, but also the potential effects of the seal’s environment.
Preventing Seal Failure
Seal failure will lead to equipment problems and costly downtime. And while they are durable if used in proper applications, in the wrong setting they can cause serious problems.
Even if a hydraulic system continues to operate safely when leaking, leaks will be costly. Six drops of oil a minute leaking from a connector in a hydraulic system — assuming the volume of each drop is 0.5 ml — is 179.8 liters over the course of a year and more than a hundred euros’ worth of replacement oil. A steady stream leak of 0.16 cm diameter adds up to 1,968 liters of lost oil per year. Now multiply that by the number of connectors used and it adds up quickly.
Such issues can be prevented, however, with an understanding of the causes of seal failure and how to prevent them. So while all seals eventually wear out, the most common causes of premature failure include improper installation, contamination, excess temperature, pressure or speed and chemical erosion. Let’s look at these concerns one at a time:
Improper installation. An improperly-installed seal can fail in a number of ways, due to improper handling, contamination or even being an incorrect fit for the application. Improper installation can result in tears or nicks to the seal, consequently leading to failure. A seal can even be installed backwards, resulting in immediate leaks.
The location where the seal will be housed must be measured correctly so that it is a precise fit. Without the correct size, the seal can either break (if too big) or not seal at all (if too small). For example, an O-ring seal size is determined by the seal bore (the diameter of the hole in the housing where the seal will be fitted), the seal outer diameter and the seal width (the total width of the seal). Seals are sized to fit a certain shaft or rod diameter and are identified as such. A seal should only be used in the dimensions that it is designed for.
Contamination. Metallic shavings, powder, dirt, mud, grit and other minute solid particles can be picked up during operation and damage the seal, possibly getting into the protected area. Causes can include internal cylinder contamination, cylinder wear over time, clogged filters, dirty oil and poor wiper performance. Any liquid used in these applications should be properly filtered of debris.
Excess temperature. Heat can cause hardening of the elastomer and can cause the seal to degrade, eventually becoming brittle and cracking apart. Material can break off, causing further contamination. There is generally a stated temperature range that is optimum for a particular seal’s use and should be adhered to. Increased temperature also accelerates aging; the temperature of the application and constant friction can decrease a hydraulic seal’s life expectancy significantly. For instance, if axial cracks at the sealing edge are visible when replacing a seal, the seal may have been exposed to excessively high temperatures. On the other hand when the operating environment is too cold a seal may become brittle.
Pressure. When a seal is stressed beyond its limits and fails, it could be the result of over-pressurization. Failure modes range from cracking to complete structural failure. Check for pressure spikes and make sure the seal design is rated for the pressure in the given application. Like temperature, recommended pressure for optimum performance is specified for each seal by the supplier. Seals-Shop products are specifically intended to suit a variety of hydraulic applications, from light-duty linear hydraulic to heavy-duty rotary seals and static applications and pressure and temperature specs can be easily identified during product selection. When recommended pressure is exceeded a seal wears faster. Additionally, using the wrong lubricant or oil may result in the fluid density becoming too thick or slippery, causing incorrect hydraulic pressure to be applied to the seal.
High speed rotation. If used in an environment that requires a certain speed (like a rotating shaft), the seal may not withstand the rotation speed. Seals are designed to ride on lubrication between the seal lip and a moving surface. The thickness of the lubricating film establishes the level of friction. When velocity increases, friction decreases initially, but over time at an increased velocity the frictional forces will climb, causing seals to wear. Speeds under and over the recommended range cause friction values to rise sharply, impacting the seal material.
Chemical deterioration. A corrosive fluid or incompatible chemical composition, such as oil additives, can cause the breakdown of seal material. This can occur when the improper seal material is chosen for an application. Connecting a seal to a hydraulic system using chemical fluid may create material fractures or extrusions to the material. Chemical deterioration can manifest itself in the swelling or shrinking of the seal.
Leakage prevention involves not only selecting and installing the right component for the specific application, but maintaining the conditions that allow the component to continue performing without leaking. For optimum component performance, designers must be aware of the products available that achieve zero leakage for each specific application and how to install them. Products exist to reduce or eliminate the problem of leakage, but the key is in selecting the right product — and installing it correctly — for the application at hand.
Seals-Shop offers a wide range of Trelleborg Sealing Solutions products to fit applications ranging from light-duty linear hydraulics to heavy-duty seals. With materials such as high-performance thermoplastics, polymers and elastomers, all seals on the online platform are specifically developed to help a system reach its optimal performance and maximum durability with minimum maintenance. The company is based in Stuttgart, Germany, and serves many areas of industry, including service and maintenance, repair, manufacturing, wholesale and research and development.
O-rings, the most popular seals, are used mainly in static sealing applications (meaning there is no movement between the sealing surfaces or between the seal surface and its mating surface). Seals-Shop offers O-rings with cross sections in the range of 0.8 to 8.4 mm and inside diameters up to 810 mm. O-rings can be used to seal practically all liquid and gaseous media and they are available in elastomeric and other materials, including ethylene propylene diene monomer (EPDM) rubber, fluoroelastomers (FKM) and nitrile butadiene rubber (NBR).
Hydraulic rod seals prevent fluid leakage from within the cylinder to the outside. The online platform offers a wide range of rod seals for both single-acting and double-acting systems. Rod seals are available as Turcon® polytetrafluoroethylene (PTFE) products and Zurcon® polyurethane (PU) U-cups, where the focus of the design is on low friction, compact form and simple installation.
Hydraulic Piston seals are installed in the cylinder head and seal against the cylinder bore to ensure that pressurized fluid does not leak. This allows pressure build up on one side of the piston, making the cylinder extend or retract. Piston seals can be double-acting (pressure on both sides) or single-acting (pressure on one side) and are available from Seals-Shop in a variety of materials.
Wear rings guide the piston and piston rod within the hydraulic cylinder, preventing metal-to-metal contact. The online platform offers Slydring® hydraulic wear rings in three different material types: Turcite® for low- to medium-duty applications where there are limited radial forces; HiMod® for medium- to heavy-duty applications; and Orkot® materials for heavy-duty applications where there are high radial forces.
For more technical information on the handling of seals as well as installation guides, visit Seals-Shop.com.Show More Show less
Mar 28 2018Product article
Application Areas of Hydraulic Rod SealsThe rod seal is a crucial element in fluid power systems, as it prevents fluid leakage from the hydraulic cylinder. Such leaks undermine equipment performance and service life but can be avoided by attention to seal characteristics that meet the specifications for a given application.
The appropriate elastomeric rubber for fluid movement, vibration isolation or other use is defined based on system pressure, chemical compatibility, temperature regime, friction and economic considerations for single- or double-acting seals. The distinguishing requirement for a single- or double-acting seal is pressure direction: Single-acting seals take pressure from one side only and are used between fixed components while double-acting seals handle pressure from both sides and are installed between parts that are in relative motion.
Rod seals supplied by Seals-Shop are available as O-ring energized polytetrafluoroethylene (PTFE) products and polyurethane (PU) U-cups, all from Trelleborg Sealing Solutions. The design and material focus is on low friction, compact form and simple installation.
Turcon®, a proprietary PTFE-based sealing material, is compatible with almost all chemicals, making it suitable for use in equipment where seals are likely to be exposed to demanding media. These materials deliver excellent low friction and self-lubricating characteristics for dynamic and rotating applications. The low-friction properties reduce power loss while positional accuracy and control are enhanced by the elimination of stick-slip movements and conditions.
Different grades made with special processing methods and incorporating fillers can be fabricated to achieve specific operating properties. For example, Turcon® Stepseal® 2K is a single-acting O-ring energized rod seal designed to provide high static and dynamic sealing results. It can be installed together with other seals in a tandem configuration for advanced static and dynamic tightness and is marked by high-extrusion resistance, low friction with no stick-slip, minimal break out force and high wear resistance.
A double-acting O-ring energized rod seal for dynamic applications also offers low friction with no stick-slip, minimal break out force and high wear resistance. The trapezoidal cross-section of the Turcon® Glyd Ring® T provides very good static leak-tightness and the angles of each lip are designed to provide improved leakage control and better resistance to extrusion.
Another high performance polymer family for sealing service is available in a range of compounds, additives and hardness levels to optimize sealing element compatibility and performance with diverse industrial fluid media types. The Zurcon® line of injection and cast molded polyurethanes is designed to meet the rigorous demands of hydraulic and pneumatic sealing systems. High mechanical strength and abrasion resistance as well as the ability to withstand petroleum oils are hallmarks of this material.
The Zurcon® Rimseal is a single-acting rod seal energized by an elastomer O-ring, providing high static and dynamic leak tightness and high wear resistance. It functions as a suitable secondary element to ensure reliable sealing of thin oil films at low secondary pressures.
The Zurcon® U-Cup RU9 can be specified for applications requiring very high sealing performance with lower friction and lower heat generation than standard U-cups. The trimmed lip design allows for outstanding wear and extrusion resistance. Compatible with virtually all media, it also has a wide operating temperature range (from minus 35 degrees Celsius to 110 degrees Celsius).
Proper hydraulic-cylinder operation hinges on choosing the best seal for the job. A good working knowledge of available seal options and application parameters — such as fluid pressure range, temperature range, stroke speed and fluid type — helps achieve that goal. For more information on rod seals and for installation guides, you can visit Seals-Shop.Show More Show less
General Information - Trelleborg Sealing Solutions Germany GmbH
Brands - Trelleborg Sealing Solutions Germany GmbH
Turcon® is a perfluoroelastomer (FFKM) compound from Trelleborg Sealing Solutions which is matched to the needs of critical sealing environments, combining the media resistance of a PTFE with the elasticity of an elastomer.
Turcite® is dimensionally stable and wear resistant with excellent performance in dry and boundary lubrication.
The engineered plastic based sealing material Zurcon® provides outstanding wear resistance combined with good friction properties, making it suitable for reciprocating, slow rotating and oscillating applications.
HiMod®, a high modulus thermoplastic is suitable for custom molded components, reinforcing rings and Back-up Rings.
The composite bearing material Orkot® consists of technical fabrics impregnated with thermosetting resins and evenly dispersed solid lubricants gives unrivalled performance in dry running conditions.
Location - Trelleborg Sealing Solutions Germany GmbH
Executives - Trelleborg Sealing Solutions Germany GmbH
Mr. Carsten Stehle
Chairman (Chairman of the Board)
Key figures - Trelleborg Sealing Solutions Germany GmbH
Opening hours - Trelleborg Sealing Solutions Germany GmbH
Participation - Trelleborg Sealing Solutions Germany GmbH
Activities - Trelleborg Sealing Solutions Germany GmbH
- Moulded parts, rubber
Rings and washers, rubber
- Diaphragms, rubber
- Packing rings, rubber
- O-rings, rubber
- Rings, rubber, for screw stoppers
- Rings, rubber cord, sealing
- Rings, cellular/foam rubber, sealing
- Rings, rubber, conical, sealing
- Rings, rubber, hexagonal, sealing
- Rings, rubber, flat, sealing
- Rings, rubber, square section, sealing
- Bushes, rubber
- Seals, rubber
- Seals, rubber, for bottles and jars
- Seals, rubber, dam and lock gate
- Rings, rubber, to customer specification
- Tapes and straps, plastic
Jointings, packings and gaskets, plastic
- Gaskets, ethylene-propylene-diene monomer (EPDM)
- Gaskets, polyethylene (PE)
- Gaskets, polytetrafluoroethylene (PTFE)
- Gaskets, polytetrafluoroethylene (PTFE) filled
- Gaskets, polyvinyl chloride (PVC)
- Gaskets, plastic, for glazing and draught-proofing
- Packing rings, plastic
- Packing rings, vee type, plastic
- Packings, polytetrafluoroethylene (PTFE)
- Oil seals, plastic or synthetic rubber
- O-rings, polytetrafluoroethylene (PTFE)
- Seals, filled polytetrafluoroethylene (PTFE)
- Jointing materials, plastic
- Plastic products, industrial use
- Plastic products for the mechanical engineering industry
- Plastic products for the electrical and electronics industries
- Seals and gaskets, metal
- Packings, metal
- Internal combustion engine components NES
Other classifications (for some countries)
NACE Rev.2 (EU 2008) : Manufacture of other rubber products (2219)
ISIC 4 (WORLD) : Manufacture of other rubber products (2219)