The Technical Hub
O-Ring Calculator
This interactive calculator assists engineers with selection of O-ring and hardware dimensions, and to form the basis of an O-ring installation.
Chemical Compatibility Checker
This interactive guide will help you choose a seal material based on existing compatibility test results of known chemicals and elastomers.
Interactive Engineering Calculators
Click here for volume, mass and compression set values for O-rings and rotary seal and hydraulic cylinder calculations.
Unit Converter
Our interactive conversion tools allow engineers to switch between units of measurement when preparing engineering calculations.
Engineering Tables
Our reference tables provide cross reference information for surface finish, metal hardness and polymer hardness measurement units.
Using Finite Element Analysis (FEA) in seal designFinite Element Analysis (FEA) is a computerised modelling method for predicting how an object reacts to forces. This could be whether directly applied or generated by pressure, temperature effects or vibration. (more…)
Surface finish requirements for static and dynamic sealingWhat is hardware surface finish? Any surface can look (and even feel) perfectly smooth. However, look closely enough with high magnification and all surfaces will have a degree of fluctuation and a topography that looks similar to a mountain range or the surface of the moon. The roughness of a surface is generally linked to the way a surface is produced or machined, and any subsequent processes such as coating or platings. Ra (metric) is the unit of measurement for surface hardware finish. Ra simply, is the mean roughness; the average calculated from the peak heights and valley depths. A surface that is mostly spiked can have the same Ra value as one that is mostly troughed, but each could have a very different impact on seal performance. Surface finish measuring equipment is capable of tracing a surface finish using a diamond tipped stylus or non-contact 3D laser scanning. Static and dynamic sealing applications will have different requirements for seal finish. Measuring and analysing the hardware surface finish is important to ensure the correct conditions and no leakage occurs. If a seal application is static, and is sealing a low molecular size gas such as helium, for example, then a very smooth surface is preferable. For some dynamic applications, it can be critical for either seal friction, or wear life, that the interface between the seal and the hardware is well lubricated. Specifying the right surface finish for the hardware components that contact a seal can be complex and daunting. Our expert team advise our customers on the relevant parameters, with consideration to what is important for the given application. We ensure the optimum finish is fully specified to achieve right-first-time seal performance. Find out how our expert quality engineers and inspectors ensure the highest level of quality assurance HERE
Are all elastomers the same?Elastomer rubbers look very similar - but are they all the same? With many different base groups and recipe formulations, there's a huge range of elastomer materials suitable for applications with varying temperature ranges and chemical media compatibility. It's critical to the seal performance to make the right choice. There are number of factors to consider, these include: Material hardness Elastomer material hardness can impact assembly loads, seal friction and extrusion resistance. Softer seal compounds can be used effectively against rough hardware surface finishes, as the softer rubber can better accommodate surface imperfections (especially when sealing low pressure gas). Harder compounds will have greater wear resistance in dynamic applications. Chemical compatibility Unlike PTFE seals (where there are very few chemicals that will attack and breakdown the material) elastomer seal materials have to be carefully selected. It's important to ensure properties are not affected by any fluids or gasses that the seals come into contact with. Temperature range Outwardly, elastomer rubbers seem straightforward, but the technology can be complex. Material groups often have well published temperature ranges. For example, the silicone family is able to reach -100°C (or even lower with special grades), and perfluoroelastomer (FFKM) grades are able to withstand 320°C (or even higher for short durations). Whilst guidance can be given on maximum temperature capability for any specific elastomer grade, this is often in a benign air environment. Therefore the chemical impact of being exposed to hot fluids in the sealing application should be considered. For information about our extensive product range, see HERE
The importance of engineering tolerancesTolerances are present in every man-made item. It is practically impossible to repeatedly manufacture something to an exact size or specification. In seal manufacturing, it's important to understand which tolerances impact performance and by how much. This will ensure a system is optimized for overall performance, and whole-life product cost. Considerations for tolerances include the seal material and the hardware for sealing installation.
Seal material, polymer and metal seals
Almost all polymer seal materials contain multiple ingredients. For PTFE and polyurethanes this is typically 2 or 3 different elements. Additionally, for an elastomer material, as many as 30 different ingredients can be used in the recipe. In machined seals, polymer seal materials tend to have high rates of thermal expansion. Together with their relative softness, this makes it difficult to maintain the same level of tolerance that can be achieved when machining metal components.
Hardware tolerances
When designing hardware for seal installation, engineering tolerances are sometimes more obvious, and certainly where engineers can focus some attention. A stack-up of tolerances for many applications should be considered. Together with tolerances of the assembly such as concentricity or misalignment (especially for dynamic sealing applications). Other considerations include bearing wear and the resulting increase in misalignment or runout as the equipment approaches the end of it’s target life.
Why are engineering tolerances important for sealing systems?
Every application starts from a nominal condition, and the maximum and minimum tolerance conditions should always be considered. Even in seemingly straightforward applications, it's important to ensure the seal is continuing to operate within it’s ideal set of conditions. Click on the link for information about our engineering, design and innovation service, click on this link HERE Use our interactive tools HERE
Elastomer manufacturing moulding processesHow is it manufactured? A question we get asked in the seal design process, but perhaps not considered often enough. How a rubber seal is produced can affect a number of things; the cost, the material choice...even how a part should be designed. All of these can have a significant impact on the performance of the seal in application. Let's take a look at the three main manufacturing methods for moulding elastomer seals. Compression Moulding This is the most simple method of converting a piece of rubber into a finished seal product. First, the rubber compound is mixed and prepared. The material has a stiff and non-elastic consistency (like thick dough). From this dough we produce a rubber blank (also known as a pre-form) by either cutting, punching or extruding cord. These blanks are normally a little bigger than the finished part (normally based on weight) will be placed into a metal moulding tool. The tool (in its simple form) is in two halves with the final product shape cut into the metal. This is known as the mould cavity. Injection Moulding This manufacturing process is often used to produce plastic components, but for rubbers, the temperatures are switched. A warmed rubber is injected into a hot tool, as the force required to inject uncured rubber is much greater than what’s required to push molten plastic into a chilled mould. Otherwise the equipment and principles remain similar. Transfer Moulding This is a variation on compression moulding. It uses the same hydraulic compression presses, but this tooling is a little more sophisticated (and consequently a little more expensive). Comparing the three most common methods of producing an elastomer seal, it's clear that evaluating how the part is going to be made, is key to ensuring the technical and commercial success of the seal in the application. Read more about our engineering, design and innovation service HERE
Polyurethane as a seal materialThe foam in your armchair. The strap on your wristwatch. The wheels on a supermarket shopping trolley and beyond; Polyurethane certainly has a diverse range of uses since its invention almost 85 years ago. Aside from day-to-day products; it is also a highly capable and versatile sealing material - and an option that is often overlooked.
What is Polyurethane?
This material is rubber, plastic, rigid and flexible. Polyurethane covers a group of materials; plastic polymers produced by the combination (or synthesis) of di-isocyanates with polyols and a chain extender. This makes Polyurethane an excellent seal material.
How are Polyurethane materials manufactured?
There is a one and two-step process to manufacturing polyurethane.
One-step process
This is when a compound containing multiple hydroxyl groups (called a polyol), is mixed with highly reactive low molecular weight chemicals (isocyanate), and a chain extender (low molecular weight diols or diamines). Consequently, the result is a random copolymer with a physically cross-linked irregular molecular structure.
Two-step process
In a two-step process, the polyol and isocyanate are mixed first to produce a pre-polymer. This is mixed with the chain extender to produce a block copolymer with more regular molecular structure. Although this often results in improved and more consistent material properties, there is a slightly higher production cost.
Why is Polyurethane a good seal material?
Evidently, when formulated appropriately, Polyurethane does produce an impressive set of material properties that make it an ideal material for sealing products. Consequently, its flexible, with very high abrasion resistance, tensile strength and stiffness. The tensile and tear strengths are typically 3-5 times higher compared to rubber seal materials. Although it lacks the chemical resistance and temperature capability of PTFE, it is compatible with mineral oils. There is more information on polyurethane as a seal material HERE You will learn more about our range of materials HERE
Diaphragms for precise control in critical applicationsIn applications that require precise and rapid pressure responses, our diaphragms offer an engineered sealing solution for high performance valves and actuators. Why use diaphragms? Diaphragms provide excellent sealing results in multiple applications. For example: Valves, actuators, pumps, pressure & flow control, pressure switches/sensors, dispensing, metering, ventilation, and media separation applications. Valves and actuators controlling the flow of liquids or gases frequently utilise diaphragms for fast responses to small pressure changes. The sensitivity to signal pressure changes will give reliable valve positioning (with very low hysteresis, for example). Additionally, successful sealing in large diameter, high pressure and long stroke applications can all be achieved with the right design. Large diameter & long stroke engineered diaphragms We supply diaphragms in a wide selection of materials including elastomers, fabric reinforced and thermoplastics. Additionally, our range of diaphragms are an excellent seal of choice for a variety of hydraulic and pneumatic applications. Are diaphragms suitable for your application? Our experienced team of application engineers will design your seals and use the latest developments for each individual application. Additionally, we provide a complete seal design service from start to finish. As well as optimal sealing performance in an application, we will assist with hardware design to provide the most cost-effective sealing package. We will optimize the tooling in key areas to produce complex geometries. This is achieved by using modelling and specialist FEA technologies to predict the performance of fibre & fabric reinforced materials. Manufactured in a range of materials with industry specific approvals, our diaphragms are used in applications across many different markets. These industries include oil & gas, process control, potable water management, LPG & natural gas, life sciences and food & beverage. Learn more about diaphragms on this link HERE
Rotary seals for heavy duty transportationSupply Plus Ltd designs, manufactures, supplies and distributes safety and fuel delivery equipment, with brands including AS Fire & Safety, Bayley and Collins Youldon. The application Our customer, Supply Plus approached us with a requirement for their 2” Swing joint power spindle. The outlet pipe from the fuel tank on delivery vehicles is fed into the centre of a rotating hose reel. This is located between the tank and cab of the vehicle. This is powered by an electric motor and pumped through at relatively low pressure. The current design experienced issues of leakage from the hose fitting in low temperatures especially at -25°C, and particularly when vehicles are parked overnight. Therefore we recommended a rotary seal for this heavy duty transportation. The challenges This application required a rotary seal with low temperature capability and excellent resistance to oil-based fuels. A design was required to replace the existing seal in the available housing between the rotating metal faces. Therefore a standard spring energised rotary seal would not work in the application; a bespoke design was required. Leakage at night when vehicles are not in use often means the issue worsens because the seal is cold and not energised. Therefore, we designed a rotary seal for heavy duty transportation that would remain energised at low temperatures and low pressure. Our sealing solution Our engineers designed a simple but effective seal, incorporating a large heel in the base of the housing. This energised a lip sealing on a rotating metal face. The volume of rubber in the heel of the seal, combined with the 170° angled base, created sufficient force to maintain a seal at low pressure. We used a low temperature Viton ensuring the seal retained elastomeric properties and applied the sealing force at low energising pressures and very low temperatures. This also provided excellent resistance to fuel oils, diesel and aviation fuel. We tested prototypes at both an in-house test unit and in the field over four winter months. Results showed no issues during dispense of fuel and a complete cessation of leakage. The seal was approved and production orders placed, and the design has been incorporated across additional sizes of hose reels. Learn more about our rotary seals HERE
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
Moulded gaskets for an automotive applicationAn existing customer (an automotive manufacturer) approached our engineers with an application where they were experiencing failures of a seal designed and manufactured by another rubber seal provider.
The application
This moulded gasket is used within a valve housing in an automotive application. The competitor gasket experienced failure at the “T-junction” areas of the seal. Our customer had experienced chronic failures of their existing moulded gasket design at high temperatures and high pressures. The seal is required to perform under pulsating pressure of up to 50 Bar and temperatures of up to 150°C. Our engineers reviewed the existing gasket design and application conditions and recommended an increase in height of 0.40 mm. This was to increase the compression and improve the sealing function. Additional beads were also added to further stabilise the gasket in the groove.
The challenges
Prototype parts were manufactured from a single cavity soft tool and sent to the customer for in-house testing and validation. The prototype gaskets very nearly passed testing but did not quite reach the 50 Bar pressure requirement at 150° C (42 Bar reached). This was still a great improvement on the performance of the customer’s original gasket. Analysis of the customers test data and images of the tested parts, determined there were areas where the gasket was sliding in the groove and then shearing as the pressure pulsed. We resolved this issue by our engineers adding beads to the rear of the T-intersections of the gasket. This provided additional support and further stabilised the gasket at the high-pressure stress points in the groove, and reduced movement within the housing. The number of additional beads added needed to be balanced carefully with calculations on groove fill. Further development captured the cleanliness requirements and altered radii on the beads.
Customer satisfaction
The new design was approved, and the customer moved to production tooling stage and sample parts were produced to PPAP Level 3 for production. More information about our mouldings & gaskets on the link HERE
Special O-rings for an automotive applicationOur customer manufactures high performance oil and vacuum pump solutions, and approached our engineers with a new O-ring application for review.
The application
Our customer required an FKM (Viton™) 60 shore special O-ring. This is to meet Porsche material specification PN707 Class 2 (Oil), Class 5 (Fuel/FAME mix) and Class 12 (Blowby gas). This proved to be a very cost sensitive project with a short lead time. Additionally, we did not have an existing grade in our materials portfolio to meet this specialised O-ring specification.
The challenges
Our engineers reviewed the application and we provided two material options. The first is a lower cost grade of FKM (Viton™) A grade, and would possibly meet the Porsche specification required. The second material, a medium to higher cost FKM (Viton™) B grade that will definitely meet the specification. We supplied a quotation for the two material types. Additionally, the quotation included production tooling, PPAP Level 3 submission, testing for both materials and a pre-production batch of O-rings. The project was urgent and we were able to accommodate PPAP Level 3 grade O-rings for both materials to be manufactured from the same tool. Also, to save time we conducted material testing in tandem with the manufacture and preparation of the the production tool. The choice of compound to be used in the tool would be made on review of the results of material testing. On completion of the material testing, the customer reviewed the results with Porsche. The decision to produce O-rings from the FKM B grade was made.
Customer satisfaction
By this stage of testing, production tooling was complete, allowing manufacture of PPAP 3 samples and the pre-production batch to commence. Pre-production O-rings were supplied to the customer in the promised 12-week lead time together with PPAP Level 3 and PPAP 3 samples. See this link for more on our O-ring range and expertise: HERE
High speed Rotary seals for electric vehiclesThe electric vehicle industry is growing; global manufacturing and registrations of electric vehicles is increasing exponentially each year. Our engineers have extensive experience in designing seals for automotive applications, but we still find new challenges involved in sealing components within hybrid, hydrogen fuel and full battery powered electric vehicles.
Silicone O-rings for De Soutter EcoPulse™ lavage systemDe Soutter Medical Ltd specialises in the development, production and worldwide distribution of high performance orthopaedic tools for surgical procedures, offering their customers a comprehensive range of technically innovative and high quality products.
Gold plated metal seals for Oil & Gas couplingsOur customer designs and manufactures hydraulic distribution products and systems used to control subsea production systems for the offshore energy industry globally.
PTFE Rotary Seal for Oil & Gas drilling toolOur customer designs and manufactures a leading range of unique downhole technology and drilling solutions that contribute to a net zero energy industry.
Why the focus on PFAS?PFAS is a blanket term used to describe Poly- and Per- fluoroalkyl substances. There are currently around 10,000 substances in existence that fit this description, with potentially more variants still yet to be produced. Some are already known to be harmful to human and animal health and the environment (such as PFOA and PFOS), and these specific PFAS are already controlled under legal restrictions. But in February 2023, The European Chemical Agency (ECHA) published a regulatory proposal to further restrict the manufacture, placing on the market, and use of all PFAS within the EU.
Seals for cryogenic applicationsCryogenic sealing means controlling or sealing a media at very low temperatures. This process can be complex and advanced, and spans a range of markets; from pharmaceutical, chemical and refrigeration, to automotive and electronics.
Why use 2-Shot moulded seals?2-Shot moulding is a manufacturing process that allows the co-polymerisation of hard (or soft) plastics and thermoplastic elastomers (TPE’s). We use the 2-Shot manufacturing approach to deliver engineered parts that perform a critical sealing function.
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.
Why use metal seals?The use of metal seals as an engineered sealing solution is appropriate where it is not possible to use elastomeric or polymer seals due to extremely demanding application requirements. For example, these could include applications with extremely high temperatures (300°C upwards) and pressures, intense radiation, cryogenic conditions or highly aggressive chemicals.
Why use Push-in-Place gaskets?Where a seal groove follows an irregular path or profile, a common sealing solution is to design a custom Push-In-Place (PIP) gasket that has the same profile as the centre line of the groove, simply drops into place and is retained by the features of its own design.
Perfluoroelastomers in valvesIs it time to re-visit using perfluoroelastomer seals in your valves? First developed by DuPont™ in the late 1960s, perfluoroelastomers (or FFKMs), are now widely known and understood in a variety of markets. But for those that may be less familiar with these high performance materials, here is a quick recap...
Seals for electric vehiclesPropelled by one or more electric motors and using energy stored in rechargeable batteries, electric vehicles are quieter, have zero exhaust emissions and lower emissions in general compared to internal combustion engines. The number of electric vehicles on the road grows exponentially every year globally, and our engineers support manufacturers with innovative sealing solutions in these specialist areas of application.
Seals for valve applicationsValves are imperative for isolation and control functions, and can be found in a broad range of industries such as Oil & Gas, Water & Wastewater, Food & Beverage and Hydraulics & Pneumatics. We supply seal products into valve applications in a variety of styles including ball, gate, flap, plug, butterfly, spool, check and solenoid valves.
Seals for Oil & Gas applicationsWith diverse applications in harsh environments, the Oil & Gas industry presents some of the most challenging demands on engineered sealing solutions. Our collaboration with Parker Seal Group allows us to integrate their materials and sealing expertise to meet our customer demands.
Seals for Life Sciences & Medical ApplicationsWhen designing and manufacturing sealing solutions for applications within critical devices and equipment, the strictest demands in product integrity and the highest specifications of hygiene and cleanliness must be met.
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.
Seals for Semiconductor ApplicationsSemiconductor and electronics manufacturers are facing greater demands for more complex and powerful devices to fulfil applications across all industry segments. High performance seals and ultra high purity elastomer materials are crucial for these critical 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.
O-rings with special coatingsAll seals require some form of installation into application hardware and often this may seem to be a simple push in place function. However, without consideration of certain conditions this can potentially create sealing problems further into the life cycle of the seal. Once installation is achieved a seal can often sit in the housing hardware for many months...which potentially allows it to stick to the housing material and cause further issues. This is where special coatings can make a difference.
Tools
O-Ring Calculator
This interactive calculator assists engineers with selection of O-ring and hardware dimensions, and to form the basis of an O-ring installation.
Chemical Compatibility Checker
This interactive guide will help you choose a seal material based on existing compatibility test results of known chemicals and elastomers.
Interactive Engineering Calculators
Click here for volume, mass and compression set values for O-rings and rotary seal and hydraulic cylinder calculations.
Unit Converter
Our interactive conversion tools allow engineers to switch between units of measurement when preparing engineering calculations.
Engineering Tables
Our reference tables provide cross reference information for surface finish, metal hardness and polymer hardness measurement units.
Articles
Using Finite Element Analysis (FEA) in seal designFinite Element Analysis (FEA) is a computerised modelling method for predicting how an object reacts to forces. This could be whether directly applied or generated by pressure, temperature effects or vibration. (more…)
Surface finish requirements for static and dynamic sealingWhat is hardware surface finish? Any surface can look (and even feel) perfectly smooth. However, look closely enough with high magnification and all surfaces will have a degree of fluctuation and a topography that looks similar to a mountain range or the surface of the moon. The roughness of a surface is generally linked to the way a surface is produced or machined, and any subsequent processes such as coating or platings. Ra (metric) is the unit of measurement for surface hardware finish. Ra simply, is the mean roughness; the average calculated from the peak heights and valley depths. A surface that is mostly spiked can have the same Ra value as one that is mostly troughed, but each could have a very different impact on seal performance. Surface finish measuring equipment is capable of tracing a surface finish using a diamond tipped stylus or non-contact 3D laser scanning. Static and dynamic sealing applications will have different requirements for seal finish. Measuring and analysing the hardware surface finish is important to ensure the correct conditions and no leakage occurs. If a seal application is static, and is sealing a low molecular size gas such as helium, for example, then a very smooth surface is preferable. For some dynamic applications, it can be critical for either seal friction, or wear life, that the interface between the seal and the hardware is well lubricated. Specifying the right surface finish for the hardware components that contact a seal can be complex and daunting. Our expert team advise our customers on the relevant parameters, with consideration to what is important for the given application. We ensure the optimum finish is fully specified to achieve right-first-time seal performance. Find out how our expert quality engineers and inspectors ensure the highest level of quality assurance HERE
Are all elastomers the same?Elastomer rubbers look very similar - but are they all the same? With many different base groups and recipe formulations, there's a huge range of elastomer materials suitable for applications with varying temperature ranges and chemical media compatibility. It's critical to the seal performance to make the right choice. There are number of factors to consider, these include: Material hardness Elastomer material hardness can impact assembly loads, seal friction and extrusion resistance. Softer seal compounds can be used effectively against rough hardware surface finishes, as the softer rubber can better accommodate surface imperfections (especially when sealing low pressure gas). Harder compounds will have greater wear resistance in dynamic applications. Chemical compatibility Unlike PTFE seals (where there are very few chemicals that will attack and breakdown the material) elastomer seal materials have to be carefully selected. It's important to ensure properties are not affected by any fluids or gasses that the seals come into contact with. Temperature range Outwardly, elastomer rubbers seem straightforward, but the technology can be complex. Material groups often have well published temperature ranges. For example, the silicone family is able to reach -100°C (or even lower with special grades), and perfluoroelastomer (FFKM) grades are able to withstand 320°C (or even higher for short durations). Whilst guidance can be given on maximum temperature capability for any specific elastomer grade, this is often in a benign air environment. Therefore the chemical impact of being exposed to hot fluids in the sealing application should be considered. For information about our extensive product range, see HERE
The importance of engineering tolerancesTolerances are present in every man-made item. It is practically impossible to repeatedly manufacture something to an exact size or specification. In seal manufacturing, it's important to understand which tolerances impact performance and by how much. This will ensure a system is optimized for overall performance, and whole-life product cost. Considerations for tolerances include the seal material and the hardware for sealing installation.
Seal material, polymer and metal seals
Almost all polymer seal materials contain multiple ingredients. For PTFE and polyurethanes this is typically 2 or 3 different elements. Additionally, for an elastomer material, as many as 30 different ingredients can be used in the recipe. In machined seals, polymer seal materials tend to have high rates of thermal expansion. Together with their relative softness, this makes it difficult to maintain the same level of tolerance that can be achieved when machining metal components.
Hardware tolerances
When designing hardware for seal installation, engineering tolerances are sometimes more obvious, and certainly where engineers can focus some attention. A stack-up of tolerances for many applications should be considered. Together with tolerances of the assembly such as concentricity or misalignment (especially for dynamic sealing applications). Other considerations include bearing wear and the resulting increase in misalignment or runout as the equipment approaches the end of it’s target life.
Why are engineering tolerances important for sealing systems?
Every application starts from a nominal condition, and the maximum and minimum tolerance conditions should always be considered. Even in seemingly straightforward applications, it's important to ensure the seal is continuing to operate within it’s ideal set of conditions. Click on the link for information about our engineering, design and innovation service, click on this link HERE Use our interactive tools HERE
Elastomer manufacturing moulding processesHow is it manufactured? A question we get asked in the seal design process, but perhaps not considered often enough. How a rubber seal is produced can affect a number of things; the cost, the material choice...even how a part should be designed. All of these can have a significant impact on the performance of the seal in application. Let's take a look at the three main manufacturing methods for moulding elastomer seals. Compression Moulding This is the most simple method of converting a piece of rubber into a finished seal product. First, the rubber compound is mixed and prepared. The material has a stiff and non-elastic consistency (like thick dough). From this dough we produce a rubber blank (also known as a pre-form) by either cutting, punching or extruding cord. These blanks are normally a little bigger than the finished part (normally based on weight) will be placed into a metal moulding tool. The tool (in its simple form) is in two halves with the final product shape cut into the metal. This is known as the mould cavity. Injection Moulding This manufacturing process is often used to produce plastic components, but for rubbers, the temperatures are switched. A warmed rubber is injected into a hot tool, as the force required to inject uncured rubber is much greater than what’s required to push molten plastic into a chilled mould. Otherwise the equipment and principles remain similar. Transfer Moulding This is a variation on compression moulding. It uses the same hydraulic compression presses, but this tooling is a little more sophisticated (and consequently a little more expensive). Comparing the three most common methods of producing an elastomer seal, it's clear that evaluating how the part is going to be made, is key to ensuring the technical and commercial success of the seal in the application. Read more about our engineering, design and innovation service HERE
Polyurethane as a seal materialThe foam in your armchair. The strap on your wristwatch. The wheels on a supermarket shopping trolley and beyond; Polyurethane certainly has a diverse range of uses since its invention almost 85 years ago. Aside from day-to-day products; it is also a highly capable and versatile sealing material - and an option that is often overlooked.
What is Polyurethane?
This material is rubber, plastic, rigid and flexible. Polyurethane covers a group of materials; plastic polymers produced by the combination (or synthesis) of di-isocyanates with polyols and a chain extender. This makes Polyurethane an excellent seal material.
How are Polyurethane materials manufactured?
There is a one and two-step process to manufacturing polyurethane.
One-step process
This is when a compound containing multiple hydroxyl groups (called a polyol), is mixed with highly reactive low molecular weight chemicals (isocyanate), and a chain extender (low molecular weight diols or diamines). Consequently, the result is a random copolymer with a physically cross-linked irregular molecular structure.
Two-step process
In a two-step process, the polyol and isocyanate are mixed first to produce a pre-polymer. This is mixed with the chain extender to produce a block copolymer with more regular molecular structure. Although this often results in improved and more consistent material properties, there is a slightly higher production cost.
Why is Polyurethane a good seal material?
Evidently, when formulated appropriately, Polyurethane does produce an impressive set of material properties that make it an ideal material for sealing products. Consequently, its flexible, with very high abrasion resistance, tensile strength and stiffness. The tensile and tear strengths are typically 3-5 times higher compared to rubber seal materials. Although it lacks the chemical resistance and temperature capability of PTFE, it is compatible with mineral oils. There is more information on polyurethane as a seal material HERE You will learn more about our range of materials HERE
Diaphragms for precise control in critical applicationsIn applications that require precise and rapid pressure responses, our diaphragms offer an engineered sealing solution for high performance valves and actuators. Why use diaphragms? Diaphragms provide excellent sealing results in multiple applications. For example: Valves, actuators, pumps, pressure & flow control, pressure switches/sensors, dispensing, metering, ventilation, and media separation applications. Valves and actuators controlling the flow of liquids or gases frequently utilise diaphragms for fast responses to small pressure changes. The sensitivity to signal pressure changes will give reliable valve positioning (with very low hysteresis, for example). Additionally, successful sealing in large diameter, high pressure and long stroke applications can all be achieved with the right design. Large diameter & long stroke engineered diaphragms We supply diaphragms in a wide selection of materials including elastomers, fabric reinforced and thermoplastics. Additionally, our range of diaphragms are an excellent seal of choice for a variety of hydraulic and pneumatic applications. Are diaphragms suitable for your application? Our experienced team of application engineers will design your seals and use the latest developments for each individual application. Additionally, we provide a complete seal design service from start to finish. As well as optimal sealing performance in an application, we will assist with hardware design to provide the most cost-effective sealing package. We will optimize the tooling in key areas to produce complex geometries. This is achieved by using modelling and specialist FEA technologies to predict the performance of fibre & fabric reinforced materials. Manufactured in a range of materials with industry specific approvals, our diaphragms are used in applications across many different markets. These industries include oil & gas, process control, potable water management, LPG & natural gas, life sciences and food & beverage. Learn more about diaphragms on this link HERE
Rotary seals for heavy duty transportationSupply Plus Ltd designs, manufactures, supplies and distributes safety and fuel delivery equipment, with brands including AS Fire & Safety, Bayley and Collins Youldon. The application Our customer, Supply Plus approached us with a requirement for their 2” Swing joint power spindle. The outlet pipe from the fuel tank on delivery vehicles is fed into the centre of a rotating hose reel. This is located between the tank and cab of the vehicle. This is powered by an electric motor and pumped through at relatively low pressure. The current design experienced issues of leakage from the hose fitting in low temperatures especially at -25°C, and particularly when vehicles are parked overnight. Therefore we recommended a rotary seal for this heavy duty transportation. The challenges This application required a rotary seal with low temperature capability and excellent resistance to oil-based fuels. A design was required to replace the existing seal in the available housing between the rotating metal faces. Therefore a standard spring energised rotary seal would not work in the application; a bespoke design was required. Leakage at night when vehicles are not in use often means the issue worsens because the seal is cold and not energised. Therefore, we designed a rotary seal for heavy duty transportation that would remain energised at low temperatures and low pressure. Our sealing solution Our engineers designed a simple but effective seal, incorporating a large heel in the base of the housing. This energised a lip sealing on a rotating metal face. The volume of rubber in the heel of the seal, combined with the 170° angled base, created sufficient force to maintain a seal at low pressure. We used a low temperature Viton ensuring the seal retained elastomeric properties and applied the sealing force at low energising pressures and very low temperatures. This also provided excellent resistance to fuel oils, diesel and aviation fuel. We tested prototypes at both an in-house test unit and in the field over four winter months. Results showed no issues during dispense of fuel and a complete cessation of leakage. The seal was approved and production orders placed, and the design has been incorporated across additional sizes of hose reels. Learn more about our rotary seals HERE
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
Moulded gaskets for an automotive applicationAn existing customer (an automotive manufacturer) approached our engineers with an application where they were experiencing failures of a seal designed and manufactured by another rubber seal provider.
The application
This moulded gasket is used within a valve housing in an automotive application. The competitor gasket experienced failure at the “T-junction” areas of the seal. Our customer had experienced chronic failures of their existing moulded gasket design at high temperatures and high pressures. The seal is required to perform under pulsating pressure of up to 50 Bar and temperatures of up to 150°C. Our engineers reviewed the existing gasket design and application conditions and recommended an increase in height of 0.40 mm. This was to increase the compression and improve the sealing function. Additional beads were also added to further stabilise the gasket in the groove.
The challenges
Prototype parts were manufactured from a single cavity soft tool and sent to the customer for in-house testing and validation. The prototype gaskets very nearly passed testing but did not quite reach the 50 Bar pressure requirement at 150° C (42 Bar reached). This was still a great improvement on the performance of the customer’s original gasket. Analysis of the customers test data and images of the tested parts, determined there were areas where the gasket was sliding in the groove and then shearing as the pressure pulsed. We resolved this issue by our engineers adding beads to the rear of the T-intersections of the gasket. This provided additional support and further stabilised the gasket at the high-pressure stress points in the groove, and reduced movement within the housing. The number of additional beads added needed to be balanced carefully with calculations on groove fill. Further development captured the cleanliness requirements and altered radii on the beads.
Customer satisfaction
The new design was approved, and the customer moved to production tooling stage and sample parts were produced to PPAP Level 3 for production. More information about our mouldings & gaskets on the link HERE
Special O-rings for an automotive applicationOur customer manufactures high performance oil and vacuum pump solutions, and approached our engineers with a new O-ring application for review.
The application
Our customer required an FKM (Viton™) 60 shore special O-ring. This is to meet Porsche material specification PN707 Class 2 (Oil), Class 5 (Fuel/FAME mix) and Class 12 (Blowby gas). This proved to be a very cost sensitive project with a short lead time. Additionally, we did not have an existing grade in our materials portfolio to meet this specialised O-ring specification.
The challenges
Our engineers reviewed the application and we provided two material options. The first is a lower cost grade of FKM (Viton™) A grade, and would possibly meet the Porsche specification required. The second material, a medium to higher cost FKM (Viton™) B grade that will definitely meet the specification. We supplied a quotation for the two material types. Additionally, the quotation included production tooling, PPAP Level 3 submission, testing for both materials and a pre-production batch of O-rings. The project was urgent and we were able to accommodate PPAP Level 3 grade O-rings for both materials to be manufactured from the same tool. Also, to save time we conducted material testing in tandem with the manufacture and preparation of the the production tool. The choice of compound to be used in the tool would be made on review of the results of material testing. On completion of the material testing, the customer reviewed the results with Porsche. The decision to produce O-rings from the FKM B grade was made.
Customer satisfaction
By this stage of testing, production tooling was complete, allowing manufacture of PPAP 3 samples and the pre-production batch to commence. Pre-production O-rings were supplied to the customer in the promised 12-week lead time together with PPAP Level 3 and PPAP 3 samples. See this link for more on our O-ring range and expertise: HERE
High speed Rotary seals for electric vehiclesThe electric vehicle industry is growing; global manufacturing and registrations of electric vehicles is increasing exponentially each year. Our engineers have extensive experience in designing seals for automotive applications, but we still find new challenges involved in sealing components within hybrid, hydrogen fuel and full battery powered electric vehicles.
Silicone O-rings for De Soutter EcoPulse™ lavage systemDe Soutter Medical Ltd specialises in the development, production and worldwide distribution of high performance orthopaedic tools for surgical procedures, offering their customers a comprehensive range of technically innovative and high quality products.
Gold plated metal seals for Oil & Gas couplingsOur customer designs and manufactures hydraulic distribution products and systems used to control subsea production systems for the offshore energy industry globally.
PTFE Rotary Seal for Oil & Gas drilling toolOur customer designs and manufactures a leading range of unique downhole technology and drilling solutions that contribute to a net zero energy industry.
Why the focus on PFAS?PFAS is a blanket term used to describe Poly- and Per- fluoroalkyl substances. There are currently around 10,000 substances in existence that fit this description, with potentially more variants still yet to be produced. Some are already known to be harmful to human and animal health and the environment (such as PFOA and PFOS), and these specific PFAS are already controlled under legal restrictions. But in February 2023, The European Chemical Agency (ECHA) published a regulatory proposal to further restrict the manufacture, placing on the market, and use of all PFAS within the EU.
Seals for cryogenic applicationsCryogenic sealing means controlling or sealing a media at very low temperatures. This process can be complex and advanced, and spans a range of markets; from pharmaceutical, chemical and refrigeration, to automotive and electronics.
Why use 2-Shot moulded seals?2-Shot moulding is a manufacturing process that allows the co-polymerisation of hard (or soft) plastics and thermoplastic elastomers (TPE’s). We use the 2-Shot manufacturing approach to deliver engineered parts that perform a critical sealing function.
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.
Why use metal seals?The use of metal seals as an engineered sealing solution is appropriate where it is not possible to use elastomeric or polymer seals due to extremely demanding application requirements. For example, these could include applications with extremely high temperatures (300°C upwards) and pressures, intense radiation, cryogenic conditions or highly aggressive chemicals.
Why use Push-in-Place gaskets?Where a seal groove follows an irregular path or profile, a common sealing solution is to design a custom Push-In-Place (PIP) gasket that has the same profile as the centre line of the groove, simply drops into place and is retained by the features of its own design.
Perfluoroelastomers in valvesIs it time to re-visit using perfluoroelastomer seals in your valves? First developed by DuPont™ in the late 1960s, perfluoroelastomers (or FFKMs), are now widely known and understood in a variety of markets. But for those that may be less familiar with these high performance materials, here is a quick recap...
Seals for electric vehiclesPropelled by one or more electric motors and using energy stored in rechargeable batteries, electric vehicles are quieter, have zero exhaust emissions and lower emissions in general compared to internal combustion engines. The number of electric vehicles on the road grows exponentially every year globally, and our engineers support manufacturers with innovative sealing solutions in these specialist areas of application.
Seals for valve applicationsValves are imperative for isolation and control functions, and can be found in a broad range of industries such as Oil & Gas, Water & Wastewater, Food & Beverage and Hydraulics & Pneumatics. We supply seal products into valve applications in a variety of styles including ball, gate, flap, plug, butterfly, spool, check and solenoid valves.
Seals for Oil & Gas applicationsWith diverse applications in harsh environments, the Oil & Gas industry presents some of the most challenging demands on engineered sealing solutions. Our collaboration with Parker Seal Group allows us to integrate their materials and sealing expertise to meet our customer demands.
Seals for Life Sciences & Medical ApplicationsWhen designing and manufacturing sealing solutions for applications within critical devices and equipment, the strictest demands in product integrity and the highest specifications of hygiene and cleanliness must be met.
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.
Seals for Semiconductor ApplicationsSemiconductor and electronics manufacturers are facing greater demands for more complex and powerful devices to fulfil applications across all industry segments. High performance seals and ultra high purity elastomer materials are crucial for these critical 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.
O-rings with special coatingsAll seals require some form of installation into application hardware and often this may seem to be a simple push in place function. However, without consideration of certain conditions this can potentially create sealing problems further into the life cycle of the seal. Once installation is achieved a seal can often sit in the housing hardware for many months...which potentially allows it to stick to the housing material and cause further issues. This is where special coatings can make a difference.
Downloads
Contact
Product Range
Our seal products range from simple static O-rings to complex and bespoke seal designs in specialist materials. Whatever your application, we have the seal product for you.
