Special coated O-rings for renewable energy applicationOur customer manufactures wind sensors for a variety of applications in different environments. This seal application was within ultrasonic wind sensors designed for wind turbine control. The Application For optimal performance wind turbines need critical, consistent and reliable data on wind speed and wind direction measurements. Therefore we recommended special coated O-rings for this renewable energy application. The sensors that provide this must be able to operate continuously for many years, sometimes in the harshest of weather. Operating conditions are extremely challenging as the wind turbine sensors (and accompanying electronics) are exposed to fluctuating, extreme environmental changes over the years. Depending on the location of the turbines, temperatures can range from -40°C to +90° C. Additionally, humidity changes from 0-100%, and turbines are subject to rain, hail, snow, ice, lightning, vibration, sand, corrosion and altitude. Our Sealing Solution For this application, the required life cycle of the sensors is10+ years. Therefore, to achieve this, a robust protective housing for the electronics and sensors requires a series of reliable, consistent, high-quality seals. These will perform without compromise in challenging conditions. Each size of sensor requires a set of environmental seals in the separated top and bottom sections. Together with our customer’s intensive testing program, we specified EPDM O-rings (which offered exceptional ozone resistance) with a special coating. The coatings are colour coded for identification purposes according to the size of sensor. Therefore, this creates a fool-proof assembly process with no risk of error by operators. Customer Satisfaction Our range of seals have been cycle tested and approved by our customer. Furthermore, these have been built into nearly half of wind turbine projects globally. Read this link for more on our range of O-rings HERE One of our key industries is Hydrogen and Renewable Energy, learn more about our work HERE
Special coated O-rings for renewable energy application 
Why use PTFE seals?Polytetrafluoroethylene (PTFE) is a thermoplastic polymer that can be used in a variety of sealing applications; it is particularly suitable where the application conditions exceed the parameters of elastomeric seal use, but are not as highly demanding as applications that require the use of metal seals.
What is PTFE?
Discovered accidentally in the DuPont™ laboratory in Jackson, New Jersey, USA in in 1938. The molecular structure of PTFE is based on a linear chain of carbon atoms which are completely surrounded by fluorine atoms. The carbon-fluorine bonds are among the strongest occurring in organic compounds. As a result PTFE has thermal stability across a wide temperature range. It’s high melting point (342 °C) and morphological characteristics allow seal components made from virgin PTFE to be used continuously at service temperatures of up to 260 °C, and with the addition of fillers – up to 300°C. It has the unique ability to resist material degradation, heat-aging and alteration in its physical properties during temperature cycling. Alongside this rare combination of material characteristics PTFE also has unlimited shelf life.
Why use PTFE seals?
Notably PTFE demonstrates extraordinary chemical resistance: the intrapolymer chain bond strengths preclude reactions with most chemicals, thereby making it chemically inert at elevated temperatures and pressures with virtually all industrial chemicals and solvents. Only a few media (some molten alkalis) are known to react with PTFE seals making them the perfect sealing solution for highly aggressive chemical applications. PTFE also has the lowest friction coefficient of any known solid; it has self-lubricating capabilities which offers continuous dry running ability in dynamic sealing applications and has superb stick/slip capabilities.
Focus on dry coatings
The advantages of using PTFE in sealing applications are; functionality at high and low temperatures, dynamic sealing with high wear capabilities, high pressure sealing (using combinations of PEEK back-up rings) and compatibility with highly aggressive chemical combinations. Our range of PTFE seal products include back-up rings, rod and piston seals, slipper seals and spring energised seals in a wide variety of sizes. Materials depend on application requirements but we offer a wide range from Virgin PTFE or including filler combinations of MoS2, glass, carbon, carbon fibre, graphite, and bronze. These characteristics make PTFE seals perfect for the demanding applications involved in Oil & Gas, Aerospace, Automotive and Chemical Process markets (to name but a few) and Ceetak’s engineering team are experienced in the design of PTFE sealing solutions to meet the complex specifications these types of application demand. Read our overview and more detail about PTFE seals HERE
Why use PTFE seals? 
Seals for Renewable Energy ApplicationsRenewable energy is derived from our planet's natural resources such as sunlight, wind, rain, tides, waves, biomass and thermal energy stored in the earth’s crust. With increasing fossil fuel prices, and the very real threat of global warming and climate change to our planet; the development of renewable energy production sources is more important than ever. In this article, we take a deeper look into seals for renewable energy applications and the different types of power the natural world provides.
Geothermal energy and Hydro power
Geothermal energy is generated from heat from the sub-surface of the earth. Heat is produced by the decay of elements known as radioactive isotopes. This is a constant process in the earth’s core, and as a result temperatures reach in excess of 5,000˚C. Wells of up to a mile deep or more are drilled into underground reservoirs to tap into the geothermal resources. Steam from these reservoirs is harnessed and used to rotate turbines that activate a generator, consequently producing electricity. There are different designs of geothermal power plants. A dry stream plant extracts steam directly from the ground and into a turbine, driving a generator to produce electricity. The most common type are flash plants; where high pressure hot water is pumped to the surface and mixed with cooler, lower pressure water. This causes the fluid to rapidly vaporise, and the resulting steam drives a turbine. Binary power generation plants will differ from the other systems. The water and steam from the geothermal reservoir never comes in contact with the turbine units. A low-moderately heated geothermal fluid, and a secondary “binary” fluid (with a much lower boiling point than water) pass through a heat exchanger. The heat from the geothermal fluid causes the secondary fluid to flash to vapour. This drives the turbines to power the generator.
Sealing in Geothermal applications
Application conditions to consider are high temperature requirements (up to 320°C) and high pressure requirements (up to 1400 BAR). Steam is present in working turbines and drilling fluids is present downhole (which may sharply change in viscosity during operational stages). The ability to seal drilling bores with large radial gaps is required. To suit application needs, there are various materials available. For example, EPDM with steam, FKM/FFKM for high temp, NBR has high expansion capabilities to seal large radial gaps. Spring energised seals offer exceptional pressure and temperature compatibility and can be offered in NACE approved springs which are corrosion resistant. Packer elements can also assist bore alignment and offer a dense sealing arrangement which prevents cross contamination of fluids.
Hydro Power
All forms of hydropower convert energy from water flow into electricity through the operation of a turbine and generator. There are different methods of hydropower production. Three of the main techniques are Impoundment, Diversion and Pumped Storage. Impoundment uses a dam to store river water in high reservoir. The water in the reservoir is manually released and the kinetic energy of its flow (as a result of gravity) is converted to electricity through a turbine and a generator. A diversion facility channels a portion of a flowing river through a separate channel. The channel will direct the water to a turbine and turn it before it re-enters the river at a lower point. The principle behind a pumped storage facility is that water is pumped to a higher elevation, and then manually released back to the original lower reservoir. The energy that was used to originally pump the water up can be extracted by a turbine and generator for use as electricity. The idea of pumped storage is to store the energy like a battery and use this in times of demand.
Sealing in Hydro Power applications
This technology provides a range of application environments, with varying water conditions and sources. Hydro power stations contain large and heavy duty mechanisms when dictating the flow of water, and high rotational speeds will be achieved on some turbines. Wear and abrasion resistance must be considered with potential for higher load impacts from initial water release and seals in a comprehensive range of elastomer compounds must be considered to ensure compatibility between varying water conditions. Heavy duty application rotary seal designs are suitable (in some cases with metal casings, and PTFE seals are suitable for applications that require abrasion and wear resistance.
Wind Energy
This is the process of converting the kinetic energy of wind into electricity through a wind turbine. Most wind turbines have three blades, and the shape of the blades are similar to the design of an aircraft wing so that the air flow around them provides lift. The force of the lift is much stronger than the wind’s force against the front side of the blade (which is called drag). The combination of lift and drag causes the rotor to spin like a propeller. This, in turn causes rotation of a shaft at the blades’ axis. The shaft is attached to a generator, which produces electricity from the torque of the shaft. A streamlined enclosure called the nacelle houses the key components of the turbine; including the gears, rotors, braking system and generator. There is a pitch control mechanism (comprising of hydraulic cylinders) to ensure that the blades are rotated at an angle to receive the wind and encourage lift most efficiently, and a yaw mechanism (located at the base of the nacelle) which rotates the entire body so that the front of the hub faces the direction of the wind. The shaft is incorporated into a gear system which has another higher speed shaft attached to the end. The high-speed shaft provides torque to a generator which converts this force into electricity. Application conditions for seals will vary depending where in the turbine they are located. General environmental factors include varying weather conditions, vibration, contaminants, corrosion, altitude and diverse (and often fluctuating) temperature ranges (-40˚C to 85 ˚C). Often long-life cycle and ease of installation are considered important (as downtime and maintenance are extremely costly). Areas of application are broken down below.
Gearboxes
There are a range of rotational shaft speeds to consider here. Typical high-speed shafts can reach approximately 2,000 RPM so require high wear resistant seals and shaft misalignment often needs to be considered. In low speed shaft applications, contamination from outside elements must be prevented. Rotary V-Seals reduce contact pressure as RPM increases (due to centrifugal force) which allows operation at a variety of speeds and reduces the chance of heat friction/friction loss. They also offer flexible lip arrangement to compensate for shaft misalignment. Oils and grease are used to lubricate systems so multiple compounds are available for compatibility.
Braking Systems
A wide range of pressure requirements are seen; low working pressure until brakes are applied, and then high and uni-directional pressures activated. Material compatibility is considered, therefore a range of brake fluids and oils are used. O-ring energised Polypak® seals, step seals and slipper seals will seal at a flexible tolerance range and offer sealing capability at low and higher pressures. PTFE seals offer a very consistent and strong chemical resistance. Scraper seals will contain fluids in brake system compartments and prevent components running dry.
Pitch & Yaw Systems
These present both static and dynamic sealing applications, but inconsistent dynamic operation (as it depends upon wind conditions). Both low and high pressure will be seen (for example, accumulators within pitching system present up to 250 BAR). Shaft offset/misalignment must be considered in heavy duty yaw systems. Hydraulic fluids and diverse lubricants will require material compatibility choices. O-ring energised PTFE step seals will seal at a flexible tolerance range and offer sealing capability at low pressures. Sealing assemblies comprising of other products can be designed to be used in conjunction to seal against high pressures. For example, products like back up rings, wear rings and slipper seals. Polypak® seals also offer sealing when high pressure is applied and also when under ambient conditions. O-ring energisers and wear rings help to contain shaft run out.
Seals for Renewable Energy Applications
In summary, seals are a vital part of the critical function of components in renewable energy power generation. They are required to provide long term functionality and provide durability in harsh environmental conditions. Our range of engineered sealing materials are designed to withstand critical sealing characteristics in these applications, including wear resistance, high pressure and high temperature conditions. Hydrogen and renewable energy is one of our key industries. Read more HERE
Seals for Renewable Energy Applications 
3D printing for seals3D printing has developed significantly and now performs a crucial role in many applications. 3D printed products vary from fully functional to purely aesthetic applications; with the most common application being for manufacturing. Here we discuss how our engineers use 3D printing to demonstrate a seal concept.
What is 3D printing?
3D printing is typically the more common name used for additive manufacturing. This process involves the construction of a three dimensional shape that is designed and generated from a computer aided design program (or CAD). The most typical process used for 3D printing is FFF (Fused Filament Fabrication) or FDM (Fused Deposition Modelling). The FDM process uses a continuous filament of a thermoplastic material that is then deposited onto the 3D print bed, creating layer by layer and gradually building up the structure of the 3D model. This is the process we commonly use to create our design and development range of 3D printed models and seal prototypes.
What material is suitable for 3D printing?
The materials used for 3D printing must of course be compatible with the process – these include a range of thermoplastic grades. Typical suitable material grades include; Polylactic acid (PLA), Acrylonitrile Butadiene Styrene (ABS), Thermoplastic Polyurethane (TPU), Nylon and Polypropylene (PP). The most common grade we use for 3D printing is PLA – for its great strength and stability. We’ve also adapted our design process to use more TPU based material grades, as it loosely demonstrates the same properties as elastomer grades and is better for using in prototype programmes where mechanical fit in groove is tested.
Why use 3D printing for seals?
3D printing can be used for a variety of designs and seal types; from O-rings, gaskets and lip seals – to grommets, multi shot mouldings and large seal assemblies. There are many benefits of using 3D printing during the initial design stages of a project. The rapid turnaround means that a simple seal design can be produced in around 15 minutes, and even more complicated parts can be manufactured in the same day. We can even print the application housings and it’s the perfect way to demonstrate to an engineer what they can expect from a seal part in terms of shape and fit for hardware without the lead time and cost of cutting a prototype tool for moulded parts. One example of this is by quick turnaround of gasket designs typically to suit automotive applications or similar critical markets. Our engineers can design the concept and then 3D print a rapid prototype of a gasket to suit a 3D printed gauge groove. This further demonstrates to the customer that the seal has been fit checked for installation and builds further confidence in the design recommendation. Our engineers combine the 3D print with FEA simulation reports to offer a fully engineered sealing solution. Learn more about our design and simulation service HERE
3D printing for seals 
Seals for Hydrogen ApplicationsHydrogen is the most common element in our universe, and is becoming an increasingly vital part in decarbonisation and a global sustainable energy future for our planet.
How is hydrogen produced?
Hydrogen is a clean energy solution to parts of the economy that are difficult to decarbonise. These include industrial processes, domestic and industrial heating, and hard-to-electrify transport. For example heavy-duty vehicles, ships and aircraft (where battery solutions are much less practical than they are for passenger cars). The majority of natural hydrogen is not easily obtainable and is locked away as either hydrocarbons (in fossil fuels) or water. Here we detail how seals are used for hydrogen applications. Extracting hydrogen from either of these sources takes energy (and a lot of it!) but hydrogen becomes emission-free at the point of use. Today, 96% of the world’s hydrogen is produced using grey and brown processes, consequently, in reality it’s not very environmentally friendly at all. It is widely accepted that we need to switch to and expand green hydrogen production. However, the electricity sources for green hydrogen (solar, wind, etc) are not always located where the hydrogen needs to be used. Consequently, cannot be turned on and off as energy demand fluctuates.
How is hydrogen obtained?
Hydrogen can be obtained in a variety of different ways, and each of these methods is generally categorised by a different colour. Grey hydrogen is produced by reforming natural gas (methane). Brown hydrogen is produced by converting carbon rich materials (such as coal) into hydrogen and carbon dioxide. These are common processed, but both result in substantial carbon emissions. Turquoise hydrogen is produced by the pyrolysis of methane at temperatures over 1000°C. Solid carbon is a by-product which can then be used or buried without emitting greenhouse gases or causing groundwater pollution. Blue hydrogen is generated by the steam methane reforming of natural gas. This generates large amounts of CO2 which must then be captured and safely stored. Pink hydrogen is created where large amounts of electricity is used to chemically split water into hydrogen and oxygen. Manufactured from a nuclear power plant, it’s free from ongoing emissions (other than those emissions produced in building the nuclear power station). The oxygen can be used by industry or vented to the atmosphere, with no negative effects to the environment. Green hydrogen is also produced by electrolysis of water. However, the electricity required is taken purely from renewable sources such as solar, wind, tidal and geothermal processes. This is widely regarded as the ONLY totally clean hydrogen extraction method. Today, 96% of the world’s hydrogen is produced using grey and brown processes. This means in reality it’s not very environmentally friendly at all. It is widely accepted that we need to switch to, and expand green hydrogen production. However, the electricity sources for green hydrogen (solar, wind, etc) are not always located where the hydrogen needs to be used. Consequently, cannot be turned on and off as energy demand fluctuates.
Engineered seals for hydrogen applications
Sealing hydrogen presents challenges and we need to consider the following parameters when designing a sealing solution. Gas permeability of the sealing materials with pressures of 700 bar or more.
Tightness of the static or dynamic sealing surfaces – including surface finish requirements for the mating components. Hydrogen can be within a carrier. Therefore the chemical compatibility requirements of the carrier medium (e.g. ammonia or liquid organic hydrogen carriers) need to match the sealing materials specified. EPDM elastomer based solutions are often the most cost effective for seal applications in hydrogen with no particularly high demands in any one area. For permeation resistance, we offer chlorobutyl elastomer or polyurethane seals. In high pressure applications, alternatives are available. For example, elastomers or polyurethanes with high extrusion resistance and resistance to rapid gas decompression, or PTFE which is not affected by RGD. In electrolysers and fuel cells, the purity and cleanliness requirements can be met with materials and treatments we frequently use within the semiconductor market. In applications below -60°C, elastomers become hard and brittle, but PTFE, PCTFE and metal sealing solutions can be used down to cryogenic temperatures. For high temperature applications, some FKM or even FFKM elastomers can be used up to 220°C or even 300°C. However, the normal preference here would be PTFE sealing solutions. Metal seals are capable of even higher temperatures up to around 870°C. Metal seals can also have soft coatings such as tin or indium to achieve gas tight sealing, or gold or silver to reduce the risk of hydrogen embrittlement.
The evolving hydrogen industry
The hydrogen industry is technically vast and challenging for sealing applications. Extremes of temperature, alongside demanding pressure and chemical resistance requirements are challenges. Additionally, stringent leakage limits and associated safety requirements. Applications typically demand long service life and in certain cases require parts with high levels of technical cleanliness and purity. There are requirements for elastomer, polyurethane, PTFE and metal sealing solutions. It is important full consideration of the application to select the most appropriate seal design and materials. Learn more about how we serve customers in the Hydrogen & Renewable Energy Industry HERE
Seals for Hydrogen Applications 