Extrusions are discharged through special die assemblies. The elastomers are loaded into extrusion machines, heated and forced at pressure, then they slide through the die section, where they’re shaped into a desired cross-sectional outline. Continuing outwards, like toothpaste from a tube, the die-profiled extrusions assume many functional shapes, including those that have edge trims.
A Side-On Viewpoint
Viewing this gasketing medium from the side, we see its extruded profile. In one case, the synthetic rubber has been heated and pressed through an ‘H’ shaped die. There’s a curved notch on the lower half of the rubber lining, plus a subtly different notch located on the top section. Picture this material formed into a framing shape or a ring. For a custom-fabricated gasket, it precisely fits two mating surfaces because the die was perfectly profiled. For a glazing seal, the material stretches slightly when panes of glass slot into place. And that profile, the ‘H’ shape, isn’t alone. Indeed, there are limitless options here, including U-channel extrusions and hollow-tubed variations.
Extrusions: The Different Types
Materially, neoprene and EPDM rubber gaskets dominate the industry. Silicone variants and Viton alternatives are also available. Whatever the material choice, it must suit its application. Utilizing a die insert, the extrusion equipment profiles the tubular or flat-formed material lengths. U-shaped channels are squared or squeezed into ovals. For tubing seals and D-shaped inserts, there are die plates to accommodate those profiles, too. Essentially, there’s a limitless number of extrusion shapes available, each of which satisfies one of a thousand applications. However, there are material limitations and client parameters to regulate the material/shape selection process. Let’s look at those now.
Shaped By Material Limitations
Unlike geometrical shaping, this form-fitting approach depends on the application domain. For example, glazing extrusions, ones used in the automotive industry, should always source weather and UV resistant rubbers. Likewise, an extruded gasket, perhaps destined to suit some high-altitude aerospace application, won’t satisfy a client if it can’t retain its gasket-compressing capabilities when the temperature turns icy cold. Indeed, unlike pipe face gaskets, extrusions are more geometrically intricate, so a capacity for keeping that shape when attacked by the harshest environmental and/or mechanical forces ranks high here, especially when a potential seal discontinuity represents a substantial application or user hazard.
This is a second but equally relevant branch of the gasketing tree. Instead of die cutting entire shapes from a sheet, the material is pressed by a hydraulically powered piston through a toughened die. Heat and pressure are the driving forces here, and they produce some amazingly feature-rich, cut-to-length seals and gaskets. Arguably more flexible than their ring-shaped gasketing peers, extrusions assume countless cross-sectional profiles.
Full face gaskets are wide enough to cover an entire flange. That means the ring starts at the edge of the flange face, moves in towards the internal pipe diameter, and thus covers the whole seal surface. Securing bolts pass through the gasket, so there’ll be bolt holes included on the die-cut material. Talking of materials, Viton is the selected base here, with its fluoroelastomer-backed features dispensing heat-resisting resilience.
Outstanding Mechanical Performance
Applications include processing constructs that carry pressurized petroleum-based fluids. In large-scale pipes, oil refinery zones and fuel depot sections convey corrosive oils and fuels. In here, Viton type full face gaskets retain their sealing characteristics when they’re exposed to high pressures. Similarly, in chemical processing environments, the ring gaskets, compressed by circles of tightened fastener bolts, refuse to be impacted by dynamic state changing events, as encountered in catalyst-rich processing plants.
Heat Resistance Applications
Heat exchangers use streams of pressurized steam to warm independently connected heating networks. Stack and tube configurations channel the steam in, the second stream of cooler water is warmed, and the system works its heat exchanging magic. Thanks to Viton’s high-temperature capabilities, full-face gaskets made from the fluoroelastomer perform grandly in boiler-side applications. If the steam is super-pressurized or carrying hundreds of degrees of thermal energy, it just won’t matter; the bolt-tightened Viton sealed flanges will safely and surely channel the super-hot (+200°C), super-pressurized fluid. Granted, a regular Viton gasket can also manage high-temperature fluids, but blowout dangers are more likely when these seals are selected. To manage high temperatures and higher pressures, the design engineer opts for a stronger, more resilient solution. And that’s where Viton full-face gaskets enter the scene.
Chemically Based Heat Exchangers
Since Viton features moderate low-temperature capabilities (-20°C), let’s stick with the synthetic rubber’s heat-biased applications. In the above paragraph, heat exchanger technology was discussed, but the usage domain was strictly limited to hot water. That’s a popular and essentially important industry, but heat exchangers are also employed in the chemical processing sector. Efficiently isolating two or more chemical phases, Viton seals resist this triple threat. They contain heat, retain their mechanical form when high pressures flow, and they also handle incredibly corrosive chemical reagents. That three-way threat exists in chemically-based heat exchangers, so Viton full-face gaskets are also on-hand to manage the multiple fluid hazards.
Skipping up a level, flanges assume raised faces. Meanwhile, flat-surface or full-faced gasketing applications demand a compressible but rigid material base. Cut with bolt holes, the fluoroelastomer isn’t weakened by those rings of fastening apertures. To the contrary, they function with reinforced heat and pressure resisting strength across countless industrial applications.
Low-pressure pneumatic systems employ less than 75-kPa of pump compressed air. That figure can climb as high as a several hundred kilopascal load. For hydraulic equipment, the design engineer can easily pop another zero on the end of that number, for these heavy-duty systems are often asked to handle thousands of kilopascals, and those kinds of fluid loads are unforgiving, at least when it comes to a leaky gasket.
Demystifying Fluid Mechanics
As a central premise, capable hydraulic and pneumatic gaskets are designed to keep compressed gasses and pressurized liquids within fluid power equipment. The equipment employs a closed loop, with the contained fluid forces conveying energy from pumps and reservoirs to onboard actuators. Those actuators include rod and piston devices, plus several branching families of force manipulating component classes. In fact, just like electrical equipment, a whole science has sprung up around fluid transmission technology. There are complex circuit elements in the systems, plus numerous feedback-controlled network forms, many of which are built to responsively turn small signals into proportionally larger mechanical actions.
Essential Qualities For Fluid Power Transmission Gaskets
Clearly, thanks to the immense contained pressures, a leaky gasket represents a major health hazard. From one point of view, the energy losses impact machinery. The gear becomes less responsive, an outrigger fails on a crane, there’s a chassis-toppling risk, and the boom of a heavy lifter could fail at the worst possible moment. More directly, tiny leaks act like invisible jets, which can send fluid rocketing towards an unprotected eye or someone’s skin. Forcefully ejected fluids can easily penetrate soft tissue and cause serious physical harm. Unfortunately, there’s no way around this danger, not without a high-quality gasketing series. Conforming to the irregular surfaces of a pneumatic or hydraulic tube interface or flange, quality gasket seals fill microscopically tiny mating surface voids. Installed correctly, though, o-rings and flat-faced gaskets stop fluid leakage effects in their tracks.
Unique among other equipment forms, hydraulic and pneumatic equipment handle huge loads, but they’re also built to function as clean closed loop systems. That’s a tough restriction to solve. No pollutants can enter from the outside, no oils or water, air or particulates. Meanwhile, hydraulic oils can be corrosive while pneumatic gasses suck in large quantities of system-corroding moisture. The selected gaskets can’t fail when they’re attacked by corrosive oils or parts-fatiguing water, nor can they break down if the fluid emulsifies. Heat and pressure, plus a slew of other system-impacting variables are waiting for their chance to damage the fluid seals, so high-quality gasket seals are a must-have feature.
When seeking low-temperature gaskets, coolroom designers use their engineering skills to select suitable materials. A conventional sealing material, although compressible and surface conformable, isn’t necessarily good enough here, not if it becomes brittle when the temperature drops below zero degrees Celsius. Clearly, then, as well as all of the normal, highly desirable material compressibility features, freezer gaskets require a little something extra.
Studying Seal Fracturing Events
If a freezer seal does harden and become inelastic, then the slightest amount of material expansion will be enough to cause a sealant crack. All it takes is one tiny crack. Such fractures grow, they propagate until they compromise energy-efficient freezers and coolrooms. It’s impossible to stop a material from expanding then contracting, and it’s impossible to eliminate compressibility stress. It’s also plainly impossible to eliminate door seal strain, as caused by a forcefully closed coolroom entryway. Spring-loaded door closers help, but the mechanical stress still works its way into the portal gasket. As for the other system seals, there’s just no avoiding the material-deforming forces that are pushing down on their stiffening forms.
Equipped With Freeze-Resisting Resilience
To be brutally honest, those gaskets must endure, even when the enclosure temperature dips far below freezing point. Logically, then, if the cold is unavoidable, what can be done to fix matters? There are heating elements of course, which are designed to protect door gasket elasticity. Better yet, though, system designers opt for gasket materials that feature low-temperature performance. In profile, the door gaskets mentioned earlier tend to be manufactured out of extruded silicone. Double or triple layered, the strip geometry conserves energy. As a heavily reinforced door closes, the folded silicone uses an air cushion to protect the compressible rubber so that it squashes evenly all around the door frame. Expect this material to function when the enclosure temperature drops as low as -60°C. Of course, few freezers and no coolrooms require this degree of ultra-low elastomeric performance.
Silicone and PTFE gasketing materials retain their squashable features, even when they’re used in cryogenic applications. For more conventional applications, however, soft PVC, nitrile, and other synthetics are acceptable. Other desirable features, ones that play a role in the decision-making process here, include pressure handling capabilities, tensile strength, and even an aptitude for accepting magnetically charged additives. Easy to clean, not impacted by popular cleaning chemicals, and unaffected by sudden temperature spikes, the chosen gasketing elastomer should also be die-cut congenial and extrusion tool friendly. Incidentally, since coolrooms and freezers contain oil-laden foodstuffs, the selected rubber should be as oil-resistant as it is low-temperature capable.
Acids and oils course like water through wide channels. And although the compounds aren’t as toxic as those found interred inside chemical processing plants, that doesn’t mean they can’t eat their way through a rubber gasket. That’s why the food industry can’t operate for long without food grade gaskets. Anything less, well, those corrosive fluids will eventually eat away their material bases.
Seal Materials That Frustrate Food Corrosiveness
Some rubbers deteriorate when they’re exposed to acids. Other materials, they break down when heavy oils are present. Granted, the fluids here are mildly acidic, and those oily fluids are nothing more than animal fat or vegetable oil. Still, in food grade applications, those seals are exposed to acids and oils 24/7, all year round. The liquefied foodstuff could also be hot or chilled, so the selected food grade gasket better provide plenty of chemical resistance strength.
Generally speaking, gaskets that are designed to satisfy the FDA (Food Drug Administration) standards and the FSANZ (Food Standards Australian and New Zealand) lack the additives that are commonly injected into most sealing products. But let’s leave this feature alone, just for the moment. The gaskets are die cut from sheets of silicone and nitrile, from modified PTFE and other food safe gasketing rubbers. Oftentimes, for maintenance and sanitizing reasons, the industry opts for a standardized style, a white or translucent sheeting material. Clearly, then, there are weighty issues in play.
Comprehensive Gasketing Solutions
The foodstuff in the pipes could be waste, could be some stringy residue, but it could also be headed for a jar or can, which then hits the highway on the back of a truck as it heads to market. As such, food grade rubber needs more than the system-beneficial chemical resistance feature mentioned earlier. Those seals must also guarantee a food safe build. Remember, pickling juices, vinegars, oils, and salts break down gaskets, but that action occurs slowly. This is what’s known as the food leeching effect. Going back to additives, the plasticizers and fillers touched upon in the previous paragraph, food safe gaskets cannot incorporate such additives, not if they’ll end up migrating into the edible stream.
Food safe and food-proof, the rubbers used in this mildly corrosive industrial and commercial application are designed to retain their fluid sealing features and elastoviscous characteristics, even when a strong vinegar, citric acid, or salt is conveyed. Beyond that key feature, of course, the rubber gaskets, be they nitrile or silicone, must be designed to neutralize the rubber leeching effect, for this is a consumables stream, a product that’s meant for human consumption.
If a smaller O-Ring gasket ends up in the beefy hands of an installer, it’s hard to ignore that slight form. How can this seemingly trivial system component ever hope to provide sealing strength? Well, for starters, this sealing component has more geometry than a conventional gasket. It’s shaped like an emaciated doughnut, but looks can be deceiving.
The Secrets of O-Ring Gasket Strength
In truth, that geometry, the torus-like structure of it, is designed to deform uniformly when it’s placed into its cavity. Gaskets act similarly, but the compressive forces applied to those rings moves linearly along one dimension, perhaps two if we incorporate flange twisting forces. Squeezed into its companion gland channel, the flexible O-Ring material compresses equally and in every direction.
Primary Installation Tips
Going on the above passage, the first piece of advice is to ensure the rubberized ring is properly inserted into its matching cavity. Remember, the rubber is designed to be compressed radially during the installation phase. If it fits loosely, then this isn’t the right O-Ring for the job. Similarly, the diameter of the uniformly shaped band should be slightly smaller than that cavity, because the flexible material is meant to be stretched as it’s fitted.
When the cross-sectional area issue and ring diameter problems are sorted, the loop of rubber fits snugly. But does the material ring come equipped with the right fluid-handling specs? Chemical attacks are likely, temperature extremes are probable, and pressure variables certainly can’t be ignored. Select an elastomer, a silicone, neoprene, nitrile, or other fluid compatible material that will endure when it’s assaulted by any or all of these fluid forces.
Understand Application Tolerances
O-Rings can be used in static applications or in systems that employ dynamic fluid pressures. Select a product accordingly, one that fits a fixed flange or a dynamically capable variant that can conceivably function in a system that uses reciprocating cylinders. Next, avoid cross-sectional rolling. If the application does use an awkwardly located gland channel, then the installer may end up twisting or kinking the ring when it’s being fitted. Always avoid O-Ring twisting.
Check the work after the fitting is coupled. Is there an extrusion protruding from the channel? Undo the pipe, replace the O-Ring, and try again. Last of all, do understand the different elastomers, the alternate ring application usage spheres, and the knock-on effects on each and every equipment type. Is this pneumatic equipment? Is there a reciprocating cylinder riding behind the O-Ring? Essentially, this fitting is indeed slight, but its geometry and material base will operate efficiently as long as the fluid conditions and ring specifications correspond.
A pause in the narrative is on the cards, at least for this post, while we tender a structured engineering guide. Intended to function as a gasket material and application guide, the following article will list, in alphabetical order, many popular and not so popular gasketing materials and their roles in different applications. After each material, a description of its properties and commonly assigned usage areas will be listed, too.
Used for relatively low-pressure applications, places where the fluid temperature won’t exceed 120°C, this specially coated paper is saturated with a plasticized compound. It acts as a petroleum, solvent, and oil jointing medium. Expect to find paper gaskets in engine, pump, lubrication, and fuel system joints.
Again, here’s a material that performs best in low temperature and low-pressure applications. As such, this highly compressible natural substance is best employed as an oil and petroleum sealing product. It’s installed in fuel lines, designed to contain higher pressures than paper, and cork is also a naturally wear resistant gasketing solution.
Perhaps filled with the most comprehensively capable catalogue of different material types, there are thousands of different plastics and rubbers available. There’s EPDM, a popular cooling system option and a plastic that’s often found performing at its best in chemical processing facilities. If that aggressive fluid load strengthens, then turn to Viton or Teflon, which both have robust fluoroelastomer-based backbones.
From high-pressure aramid fibres to equally capable fibreglass gaskets, this material category covers a vast number of applications. Aramid seals, for example, can easily tolerate 825°C of fluid heat. Then there are cellulose and vulcanized fibres, carbon fibres and more. They retain dimensional stability, even when they’re exposed to large compressive forces. Fibre-based seals are oil, petrol, pressure, and temperature resistant, depending on their exact composition.
When the pressures carried in a fluid line reach unendurable levels, carbon steel or titanium-based rings hold back those formidable forces. They’re used along with other material inserts to seal heat exchangers, boiler pipes, massive arrays of high-pressure pumps, land-crossing oil pipelines, and in other large-scale, off-the-chart industrial applications.
This guide contains a fraction of the materials and applications that rule countless commercial and industrial usage domains. Sure, these are the mainstays, the elastomers and fibres that serve these areas best, plus they can blend with each other to form even more usable composite products, but there’s more to check out. There are felt and sponges, products that perform better in vibration-prone or food-safe environments, for instance. Without a doubt, there’s a gasket for every application, and it’s up to the engineer-in-charge to match a gasket material, plus its geometry, with the correct application.
Whether you are working with automobiles or plumbing components, it is important to have the proper gaskets on hand for your project. Finding gaskets to buy can be as simple as heading to your favourite search engine. With that being said, you won’t find quality gaskets without going to a reputable gasket manufacturer. The big question we have for our readers is this: what makes for an ideal gasket manufacturer? Today, we are going to highlight the qualities that you need to look for when shopping around for a gasket manufacturer. With our advice, you’ll be able to find the right team to provide you with the right components for your project.
Important Qualities in a Gasket Manufacturer
While there are numerous gasket manufacturers all vying for your business, there are very few that can combine the traits required in order to give you the products you need at a cost you can afford without sacrificing any service. Here are the traits that we believe make for the best gasket manufacturers. Read the following qualities and use them as a guideline as you begin shopping for your gaskets.
1) Excellent Customer Service – Leading the charge is our focus on quality customer service. In the service industry, it is absolutely imperative that companies focus on making their customers feel both welcome and appreciated. Here at Gasketech, we are well known for our focus on customer service. Every point of contact between our employees and our customers is an important one.
2) Superior Technical Performance – We aren’t solely focused on customer service because it is also important for the actual gasket product itself to be of premium quality. That is why we believe in purchasing from manufacturers who offer products with superior gasket performance. From graphite and PTFE to Viton products, Gasketech is here for you.
3) Product Availability – Customer service and superior products only work if you have access to the products when you are ready to make a purchase. It is important for all great gasket manufacturers to have a large catalogue of quality products that they can dip into in order to provide their customers with quality components.
4) Customer Satisfaction – Finally, we believe that all gasket manufacturers should be willing to stand by a customer satisfaction guarantee. After all, you are calling on us in your time of need so it is only right that we respond with great products and customer service.
For all of your gasket manufacturing needs, contact Gasketech. We provide excellent products at an affordable price, all based around your needs and schedule.
Heavy-duty industrial piping systems require equally robust gaskets, so says engineering science. Look deep, the larger than life tubular conduits are conveying higher volumes, which are held at stunningly high pressures. Meanwhile, acids and harsh chemicals are attacking the pipe seals. To keep these forces safely in check, an aptitude for optimizing a chosen gasket, one designed to counterbalance these challenges, is considered a gold standard engineering strength.
Considering Torque Parameters
Mechanics don’t throw new tyres on cars and begin indiscriminately tightening the ring of fasteners until they seem tight. Likewise, gasket installation procedures require special approaches. Torque charts are viewed and studied. Sequential bolt tightening patterns are applied all around the pipe flanges. Frankly, industrial piping is off-the-scale massive, so the adoption of these two load distributing practices will make sure the flange faces couple evenly with the interceding gasket.
Designed to Match Known Fluid Characteristics
And just how many seal impacting forces are in play? Pipe geometry and dimensions are inherent, of course, so large cross-sectional areas incur larger fluid volumes. Then there are the properties of the fluid medium, which will directly influence gasket design. Low temperatures aren’t as material-abrasive as higher thermal loads. Still, ultra-low temperatures will cause brittleness and seal fractures. Then there are super concentrated acids and caustic chemicals to address. At the end of the day, industrial piping systems require gaskets that can handle extreme mechanical loading effects. Moreover, they must incorporate a material build that won’t fail when one of the above fluid characteristics tries its abrasive best to break down the selected gasket.
A Three-Factor Guide to Industrial Gasketing
Material design is essential when we’re working with systems of industry-capable piping. However, material density isn’t the only relevant metric, so let’s skip up another rung on the gasketing applications ladder. Material suitability, as evaluated during the fluid medium management phase, is impacted by mechanical extremes, so traditional elastomeric solutions may not be enough. Composite material, fluoroelastomers, and fibrous substitutes operate alongside special laminates and metals to solve such issues. Factors one and two, therefore, are the material and mechanical features of the chosen gasket. Factor three, the dimensions of the seal, calls into action torque and bolt fastening patterns.
As a fourth gasket design and selection factor in industrial piping systems, we add Man’s influence. Preventative maintenance programs dovetail with gasket performance studies to assess the seal’s capabilities in specific operational case studies. This way, gasket design engineers can fine-tune their product families and ingrain the best possible fluid-restraining parameters into those essential flange sealing rings.
Expanded PTFE, also known as ePTFE, is a compressible gasketing material. During production, it’s stretched into sheets, with heat acting as a form expansion facilitator. The process endows the sheets with a tightly organized microstructure, a synthetic fluoropolymer base that’s a lot stronger than it looks. Used as a purpose-designed gasketing solution, the microscopic voids create a soft, irregular surface that suits a broadened number of applications.
Expanded ePTFE: A Transformation Guide
Before going any further, let’s expand that acronym. PTFE gaskets use Polytetrafluoroethylene as chemically resistant and heat tolerant seals. Elevating the material range, ePTFE physically “expands” the synthetic polymer. During the production phase, the already durable gasketing stuff is exposed to mechanical stretching energy. Fabric-softening heat provides the second structure-transforming ingredient. It’s here that the PTFE transitions, it opens up physically and assumes a web-like structure, which is filled with countless voids.
Loaded with Material Properties
Solid fluoropolymer nodes stretch into interconnected matrices. The expanded sheets are soft to the touch, and they’re very compressible. That’s a characteristic that any gasketing application can utilize. Moreover, this spongelike form is chemically obdurate, plus it can tolerate 250°C of baking hot heat or -240°C of arctic frost. To make gaskets that can take advantage of those twin properties, the rough and irregularly formed polymer base is layered into laminate strips. Now, with the ePTFE gasket positioned on a pipe flange, thousands of pounds of pressure can be applied. And, with the super-durable base matter capable of resisting the most caustic mediums, the seal won’t fail, not even when a chemical load flows with harsh corrosive impact.
Common Applications for Expanded PTFE
Conforming to match the most geometrically intricate flange faces, all while displaying a superior strength-to-weight ratio, ePTFE gaskets are mechanically robust, yet they seem deceptively soft. Expect to see this attribute employed specifically in heat exchanger technology. Over at a high-pressure, highly acidic chemical processing plant, the expanded material is working flat-out to endure high pressures while it also packs a chemical-shielding punch. Food processing complexes or solvent-based production plants, the tough fluoropolymer-based gasketing solution will reliably generate a formidable seal.
Expanded PTFE is available as laminated gaskets or as gasket tape. The polymer base does feel deceptively soft and weak, but this sponge-like form conceals a strong matrice-exploded microstructure. Capable of enduring massive quantities of compressive flange-face stress, the seals will quickly conform to the desired seal profile while maintaining the features listed above. Look for glass-lined ePTFE products if even more sealing performance is called for from this synthetic gasketing solution.