Tag: Polymer Seals

  • Chesterton® Polymer Seals for Increasing the Efficiency of Paper Machines – the Performance Lies in the Detail

    Chesterton® Polymer Seals for Increasing the Efficiency of Paper Machines – the Performance Lies in the Detail

    The pulp and paper industry uses complex paper machines that run 24/7. As in every industry, efficiency is also the key word for this sector. The goal is to achieve a high level of reliability for machine components and significantly reduce downtime for equipment repairs. With the suitable polymer seals for the various machine components, Chesterton can help to effectively extend the operational reliability and MTBF (Mean Time Before Failure).

    Paper machines consist of a variety of equipment, ranging from rotating equipment of all kinds to hydraulic and pneumatic cylinders, hydraulic directional valves, control automation, but also various types of fittings such as valve flanges and dispensing systems. Chesterton offers specific polymer seals made from high-performance materials for these different devices.

    Chesterton EPS for pulp and paper machine
    Agitator for Pulp and Paper Mill

    Rotating equipment in the paper industry: What are the challenges and how can we counteract them?

    In rotating machinery such as pumps, agitators, hydropulpers, gearboxes, fans, bearing housings, electric motors, and roll pivots, bearing failure is the main challenge. In the tough world of the pulp and paper industry, bearings are exposed to a variety of contamination including water, dust, heavy loads, vibration, abrasive contaminants and corrosive vapors. This leads to unreliability and very often to a significantly shorter bearing life.

    Bearings usually have lip seals (usually made of some kind of elastomer such as rubber) as a first line of defense. However, these only protect the bearing for a short time, far below the actual bearing service life. The rubber lip seal is there for keeping lubricant such as oil or grease inside the bearing not as protection function and was not designed for it even in many cases.

    If these conventional lip seals fail, liquid from the environment penetrates into the bearing housing. This washes away the second line of defense – the grease – and exposes the bearing metal to the extremely corrosive atmosphere. Heat, chemical load and the humid ambient conditions lead to bearing corrosion. Due to corrosion, bearings fail after a few thousand operating hours and, in the worst case, to the failure of the entire machinery. The solution to premature bearing failure is, of course, a high-quality grease for smooth bearing movement and a functioning lip seal. This can significantly extend the MTBF (Mean Time Before Failure) and the bearing service life.

    The first line of defense for equipment storage – Chesterton® Rotary Seals

    Chesterton has an extensive portfolio of excellent rotary seals, in particular the 30K Bearing and Gearbox Protection Seal, which is often chosen in the paper industry for its outstanding protective properties and durability.

    Furthermore, the split polymer seals are explicitly suitable for rotating equipment in the paper industry, offering high performance and quick and easy installation. For example, Chesterton’s patented  Matrix Rotary Seal is a split bearing protection seal developed to work on worn shafts and applications with high shaft runout.

    The non-contact Split Polymer Labyrinth Seal (SPLS) is specially developed for splash water lubricated bearing protection in large pumps, gearboxes and other rotating equipment. Here, the specific design helps to ensure effective protection: during operation, centrifugal forces and gravity ensure that the lubricant remains in the labyrinth and flows back into the bearing housing, while contamination from outside is excluded and directed back into the atmosphere.

    The R22KN5 Split Rotary Seal is used for slow-rotating applications. There are high-performance polymer materials, such as AWC860 Cherry Polymer, which are one of the best sealing solutions for pulp washer screens and filters in cellulose production.

    Product advantages and product benefits of Chesterton polymer seals for the protection of machine bearings

    • Low shaft friction
    • Sealing against external contamination of the bearing
    • Maintaining bearing lubrication
    • Long service life
    • High-performance construction and material
    • Simple installation (with split seals)
    • Extending the MTBF of rotating equipment

    Cylinder optimization with the 1-2-3 System from Chesterton – extending the service life of hydraulic cylinders

    In the pulp and paper industry, there are numerous hydraulic devices such as cylinders, presses, lifters, valve drives, pumps, control valves and directional valves. If cylinder seals do not perform adequately, leaks occur and hydraulic fluids spill out. These leakages cause contamination of the product, which leads to production losses, and have a negative impact on the environment and occupational safety.

    Chesterton EPS for pulp and paper machine

    Defective seals also provide no protection against external influences and contamination. Dirt particles enter the cylinder, causing corrosion and failure of the hydraulic system.

    Product-specific designs and complete sealing kits for cylinder applications optimize the performance of your systems. Complex packages for engineering advice, on-site support, failure analysis and retrofit components are also included in the comprehensive Chesterton service.

    The use of our high-performance cylinder seals in application-specific materials can

    • Minimize downtimes and maintenance costs
    • Improve reliability of the hydraulic system
    • Help extend the service life of hydraulic cylinders
    • Reduce the consumption of hydraulic fluid, avoid leakages
    • Significantly reduce operating costs and achieve considerable savings

    Benefit from our experience – here you can gain an insight into our field of activity:

    Case Study APAC0032 – Pulp and Paper – Polymer Labyrinth Seal

    Case Study APAC0038 – Pulp and Paper, OEM lip seal – Polymer Labyrinth Seal

    Case Study EN600351 – Spring-Energized Seals Deliver Better Performance of Offset Printing – Paper Industry

    Conclusion

    Chesterton’s advanced polymer seals increase the reliability of rotating and hydraulic equipment in all sort of Pulp and Paper plants. They help to protect bearings and hydraulic systems from wear and abrasion, enabling a longer service life for mechanical equipment. Our special polymer materials with excellent mechanical properties contribute to the efficiency of your equipment, even in the most demanding applications. Our unique split sealing solutions offer technically superior sealing and savings of thousands maintenance hours. Discover the comprehensive Chesterton portfolio.

    If you have any technical questions or if you would like assistance selecting the best sealing solutions for your specific pulp and paper application, please feel free to contact our Ask the Expert desk.

    You can also make a preliminary selection using our product selector. Our product consultants will gladly assist you in selecting the ideal product for your application.

  • Sealing Solutions for Hydropower Equipment – ​​​​Boost Turbine Dependability and Reduce Downstream Pollution

    Sealing Solutions for Hydropower Equipment – ​​​​Boost Turbine Dependability and Reduce Downstream Pollution

    For many years, Chesterton has offered hydropower facilities cost-effective hydraulic and pneumatic sealing solutions that ensure leak-free sealing and increased turbine efficiency. Worldwide, OEMs, operators, and refurbishment businesses rely on our incredibly dependable and high-quality products.

    In your cylinders, using a combination of high-performance seals and Chesterton-exclusive materials can significantly reduce total equipment costs, increase mean time between repairs (MTBR), and enhance operating performance. Our flexible manufacturing capabilities allow us to produce almost any design, any material, and any size seal with quick lead times for both molded and machined products.

    Chesterton delivers various sealing solutions for cylinders, turbines, and valves in this industry,​including:

    • Kaplan Blade Runners
    • Wicket Gate Cylinders
    • Servo Cylinders
    • Blade Pitch Cylinders
    • Brake and Jack Cylinders
    • Butterfly, Spherical, and Ball Valves

    Kaplan Turbine – Most common Type of Turbine in Hydropower

    The Kaplan turbine is an overpressure turbine. The guide vanes installed in front of the impeller create a swirl in the water. As the water flows through the water turbine, the force of the water acts on the guide vanes. This causes the impeller to rotate.

    In addition to the guide vanes, the blades of the Kaplan turbine are also movable and adjustable. This allows the angle of attack to the water flow to be changed. The guide vanes direct the inflowing water so that it hits the blades of the impeller at an optimum angle. This makes it possible to react optimally to fluctuations in the water supply and achieve a high level of efficiency even with a low water volume. Kaplan turbines are ideally suited for use with low heads and large fluctuating flow rates. The Kaplan turbine is therefore predestined for large, run-of-river power plants with low to medium heights of up to 80m.

    The Kaplan turbine has around 4 to 8 adjustable runner blades. The adjustability of the blades means that efficiency losses outside of nominal load operation can be kept to a minimum. At 30 percent to 100 percent of the nominal volume flow, the efficiency is around 85 to 95 percent. Therefore, it is no wonder that the Kaplan turbine – named after its inventor Victor Kaplan – has been shaping energy generation from hydropower for more than 100 years.

    Sealing Challenges

    There are many sealing challenges to overcome that are directly or indirectly associated with the equipment used to generate hydropower. Applying advanced sealing materials and designs can help address some of these challenges by:

    • Improving mean time between repairs
    • Simplifying installation
    • Reducing maintenance costs
    • Minimizing downtime
    • Positively impacting the environment

    Particularly with Kaplan turbines, runner blade trunnion seals are essential for preserving dependability, effectiveness, and shielding the surrounding area from oil seepage. More than 60% of Kaplan turbine leaks are caused by ineffective or failing blade trunnion seals, according to a survey done among owners of Kaplan turbines.

    Common Blade Runner Trunnion Sealing Issues

    There are several blade trunnion sealing challenges that need to be considered to establish optimal sealing reliability. They include:

    • Failure to keep water/contaminants out of the hub: Poor seal fit or poor seal design and seal material are most often the culprits, along with the impact of factors below.
    • Failure to keep oil in the hub: Also due to poor seal fit or poor design and seal material
    • Not accounting for blade droop: Due to manufacturing tolerances and running clearances of machined components, there is a certain (natural) droop of the turbine blades.

    A common bearing/bushing material for blade trunnion is cast bronze, which has a relatively low stiffness. This can lead to deformation of the bearing under high load, caused by the weight of the blade and by reaction force created on the blade during operation. Such bearing deformation will increase the blade droop value.

    The wearout of blade trunnion bearings is the third factor that can affect the blade droop value. When the blade oscillates, boundary friction arises if a stable oil-film between the trunnion and the bearings ring is not maintained. This, combined with a high radial load, might result in excessive wear of the trunnion/bearing assembly.

    Blade droop challenges the trunnion seals, changing the original cross-section for which the seals were designed. This must be compensated by the sealing devices as well. Blade droop can have a serious impact on performance, positive sealing, and seal life expectancy.

    Such geometrical changes can lead to:

    • Radial overload of the seals (in the direction where the seal cavity cross-section has been reduced)
    • Radial opening of the seals (in the direction where the seal cavity cross-section has been increased)
    • Excessive deformation and friction (wear out of sealing devices)

    How can you achieve optimal Runner Blade Trunnion Sealing?

    • Get exact turbine/blade measurements
      One of the most basic, but often overlooked aspects of selecting runner blade trunnion seals for Kaplan turbines is accounting for the wide variation in turbines and blades when determining the seal size needed. There are no technical specifications or internal standards for designing runner blade seal stuffing boxes. For this reason, and because as equipment dimensions change from the original specification after years of use, make sure you obtain actual equipment dimensions both by turbine and by blades.
    • Check the seal cavity cross section values around the blade trunnion
      It is important to understand that blade droop plays a factor in these measurements. The typical number of Kaplan runner is 4-8 blades. The natural wear of bearings and consequential blade droop values can vary blade by blade even with the same turbine. The seals should be designed and manufactured individually.
    • Check and resolve equipment conditions
      Surface conditions and the roughness of dynamic and static counter surfaces have to be considered. These uneven and abrasive surfaces can have an enormous impact on seal device performance and service life.
    • Consider operation/environmental conditions
      Fluctuation of turbine pressure – water head levels drop and rise, and can periodically change the pressure load on sealing devices. This can have an adverse impact on seal performance and reliability.
      Vibration and cavitation – a certain level of vibration and cavitation is standard to the operation of Kaplan turbines, this has a major impact on turbine components, including runner blade trunnion seals. Flexible seal design and elastic seal material can respond to such impact and withstand for a longer time.
      Low water heard schemes – Low water head can represent a high risk of abrasive environment caused by water contaminants, sediment, and mud. Using a seal with an abrasion-resistant thermoset polymer material can offset these abrasive effects.
    • Select the best runner blade trunnion seal
      Advanced hydraulic sealing technology can significantly improve meantime between failures, and reduce meantime to repair. The optimum seal also helps to reduce operational and maintenance costs, lower the risk of unplanned downtime, and lessen downstream pollution.

    Chesterton delivers the Ultimate Solution
    Chesterton Kaplan Turbine Runner Blade Trunnion Split Seal –

    High-Performance Split Lip Seal for Heavy Duty Rotary and Oscillating Applications

    Specifically for Kaplan Turbines, Chesterton invented innovative Kaplan Runner Blade Trunnion Split Seals – high-performance lip seals for heavy-duty, dynamic rotary and oscillating seals applications in the hydropower industry. These seals are specifically designed for the Kaplan (or “propeller Type” turbine runner blade trunnions.

    The Runner Blade Trunnion Seal is just one of the fully array of Kaplan Turbine product solutions available from Chesterton.

    • Faster Installation & Increased Reliability
      Because to its split design, the seal can be installed quickly and easily, reducing downtime. The removal of the blade is not required for installation and there is no need for complex welding, gluing, or post processing of the split joint. Furthermore, instead of requiring a complete stacked set, just two seals need to be installed back-to-back. This configuration also keeps the hydraulic media and lubricant in the turbine hub, and protects the hub against ingress of water, solid particles and sediments.
    • Maintains Load Pressure & Rotary Shaft Movement
      The positive, flared dynamic lip design of the Chesterton Kaplan Runner Blade Trunnion Seal prevents the split from being pulled apart by rotating motion and uses load pressure to join the cut ends. During blade positioning, Chesterton’s seal maintains load pressure and allows for rotary shaft movement with minimal frictional drag.
    • Compensates for Blade Droop
      A typical reliability issue with an older Kaplan Turbine is blade droop caused by worn trunnion bushings. The Chesterton trunnion seal design compensates by providing reliable sealing despite any droop.
    • Durable Seal Material Offers Longer Life in Hydropower Environment
      This seal is comprised of Chesterton’s AWC800 high-performance thermoset polymer material, which has a proven record of withstanding harsh operating conditions and provides exceptional abrasion resistance and durability. To reduce frictional drag, the polymer contains a built-in molybdenum disulfide lubricant. Because of its superior memory, the seal can automatically adjust and correct for radial cross-sectional differences caused by blade droop.

    Conclusion

    The Chesterton’s 22KN5 Double Acting Kaplan Runner Blade Seals in Split Interlock configuration are considered as the most user friendly and ease installation sealing solution by worldwide end users comparing to other seals as traditional rubber seals or hot welded modern polyurethanes. Optimized, smart and precise design of the 22KN5 seals combined with high performance thermoset polymer material technology provides sealing, which does not need any glue bonding, welding or vulcanization process on site, making installation simple, fast and secure.

    Do you have questions about our specific Kaplan turbine solution?  

    You can find more interesting details and information in our White Paper.

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    Please get more information about the mining applications of our sealing technology:

    In our blog, we provide information on sealing Kaplan turbines and troubleshooting leaks

    If you would like assistance selecting the best hydraulic seal solutions for your specific cylinder application, feel free to contact our Ask the Expert desk.

    You can also make a preliminary selection using our product selector. Our product consultants will gladly assist you in selecting the ideal product for your application.

  • Polymer Sealing Solutions for the Mining and Ore Processing Industry

    Polymer Sealing Solutions for the Mining and Ore Processing Industry

    In the mining busi​ness, your operation must meet critical demands and anticipate the unexpected every day to help reduce the costs of downtime. Challenging environments and destructive loads take their toll on your equipment.

    Chesterton’s industry-proven hydraulic sealing solutions provide maximum value by extending the hours of operation between maintenance intervals of your equipment and increasing overall asset life. Our custom and turnkey cylinder repair kits combine proprietary polymer technologies with unique seal geometries to increase reliability and improve productivity.

    Mega-Machines have to run constantly

    Nowadays, gigantic hydraulic excavators shovel the valuable raw materials out of the ground and continuously load huge dump trucks. The mega machines are crucial for high mine production, but they have to run reliably. Any breakdown has a significant impact on production and means financial losses for mine operators.

    The hydraulic systems on these vehicles do amazing work: they dig, lift, lower and move extremely heavy loads in dusty environments.  The performance, life and reliability of a hydraulic system is determined by several factors. In addition to the design of the components themselves and the choice of a high-quality hydraulic oil, it is the seals that ensure that the cylinders operate efficiently for a long time.

    Our hydraulic sealing solutions effectively help to increase the productivity and service life of large machinery

    Choosing high-quality polymer seals from Chesterton allows miners to:

    • Increase equipment service life
    • Increase operating hours between maintenance intervals
    • Reduce breakdowns and costly downtime
    • Reduce hydraulic fluid consumption
    • Extend leak-free operating time

    The quality of the selected sealing system determines the reliability and performance of the cylinders

    The various hydraulic systems and their different functions, such as lift cylinders, stick cylinders, steering cylinders or bucket cylinders, also differentiate in the demands placed on the sealing system. This can be, for example, higher speed, higher pressure or excessive radial load.

    Our sealing kit for heavy-duty hydraulic cylinders consisting of Wear Ring, Piston Seal, Rod Seal, Static Seal and wiper can efficiently improve the performance of the cylinder and the machine.

    What does Chesterton provide?

    We use high-performance, thermoset or even wear-resistant polyurethane material combinations that withstand high speeds, pressures and operating temperatures, have low friction, are highly elastic and have excellent tear and abrasion resistance.

    Our custom-built sealing systems allow customization to meet existing performance requirements. “Mobile Mining Kits,” individual high-performance cylinder repair kits have been proven to achieve longer off-highway machine uptime between maintenance intervals. These kits help companies control costs and maintain your profit margins by optimizing the value of equipment investments.

    Chesterton’s proprietary thermoset polymer technologies provide high abrasion and wear resistance. Our unique seal geometries are specifically designed to offset known sealing issues related to pressure spikes, side loading, contamination, and low pressure leakage.

    Please get more information about the mining applications of our sealing technology:

    Chesterton Blog “Reliability Matters” – Hydraulicseals – Reliability for Mega Mining Hydraulic Excavators

    Chesterton Blog “Reliability Matters” – Hydraulicseals – Selecting right retrofitting Mining Equipment

    If you would like assistance selecting the best hydraulic seal solutions for your specific cylinder application, feel free to contact our Ask the Expert desk.

    You can also make a preliminary selection using our product selector. Our product consultants will gladly assist you in selecting the ideal product for your application.