Bacteria accumulation can ruin product and put consumer health at risk.
Bacteria accumulation is a serious issue in the food manufacturing industry – it can ruin product and put consumer health at risk.
While many know that Polytetrafluoroethylene (PTFE) is an excellent choice for use in diaphragms and gaskets, most do not realize that there exist varying grades of PTFE. Some lower cost PTFE offerings may contain an excessive volume of pores within their structure which can harbor organic contaminants such as bacteria.
To address this problem, a calendared manufacturing process is used. Calendared PTFE is a premium grade PTFE designed for use in aseptic applications requiring ultra-high purity standards. It is ideal for use in food, pharmaceuticals and a variety of clean markets.
Distinguished by an extremely low void content, calendared PTFE resists permeation and the accumulation of foreign matter, reducing the risk of harboring unwanted bacteria or residual media.
To achieve this, the unique manufacturing process orients the chains of PTFE in a lattice-like structure that reduces voids in the material and provides it with biaxial strength. This unique structure also delivers a very high flex life. When tested in an MIT Folding Endurance Tester, the flex life of calendared PTFE is four-times greater than conventional PTFE materials.
Unlike the skived process that is commonly used for PTFE manufacturing, the calendaring process produces uniform sheets of material with consistent physical properties. This gives calendared PTFE a renowned reputation for predictable performance and quality. The opposite is true for skived PTFE where variable properties lead to varying performance and reliability.
Gylon Epix’s patterned material provides enhanced compressibility for better sealing
Gaskets are ubiquitous components in a processing plant. Every flange, equipment joint and connection point will have some form of gasket to prevent fluids from compromising (i.e., leaking from) a process system. However, effective sealing can pose challenges. A new form of polytetrafluoroethylene (PTFE) gasket, Gylon Epix, already has successfully addressed a number of persistent problems at plants.
The gasket, which is available in 3⁄32-in.-thick, 60-in. × 60-in. sheets, features a raised hexagonal pattern (Figure 1). It exhibits enhanced compressibility over both 1⁄16-in. and 1⁄8-in. traditional gaskets, seals easily when compressed by flanges and maintains assembled bolt torque better than comparable 1⁄8-in. PTFE gasket materials.
Successes with Gylon 3501-E and Gylon 3504
Trials at three early adopters of the new material underscore its value.
Fatty acid production. A German manufacturer of oleo-based chemicals, including fatty acids, glycerin, fatty alcohols and fatty esters used in consumer and personal health products, was experiencing problems sealing a 29.3-in. (745-mm) outside-diameter spiral heat exchanger. A gasket located atop the heat exchanger was exposed to polysaturated fatty acid and coolant at a continuous temperature of 428°F (220°C) and pressure of 87 psig (6 bar). J-type clamp bolts fasten the lid to the heat exchanger. Spiral heat exchangers present challenges because the gasket must seal across the entire face of the lid, requiring a gasket that will efficiently transmit the force from the bolts across its entire surface.
The traditional PTFE sheet gasket was allowing leakage across the exchanger’s spiral passes, decreasing efficiency. The gasket exhibited cuts from the spiral separation bars and required frequent changes that disrupted manufacturing and decreased plant productivity.
Gylon Epix 3501-E was installed in December 2017 and, after six months of testing, concluded it sealed well. Upon disassembly in July 2018, it was found to be in good condition, with no traces of cuts, discoloration, brittleness or sticking to the lid (Figure 2). A new gasket was installed in July 2018, which now has completed a successful one-year trial; the gasket continues to perform well.
Phosphate processing. New or refurbished equipment generally seals bolted connections well. As the equipment ages, gaskets and flange surfaces help seal gaps caused by corroded, worn, misaligned or repositioned equipment flanges. At a Mexican acid processor, Class 150, 8-in. raised-face flanges of the inlets and discharges of phosphoric and sulfuric acid transfer pumps had become worn and corroded. Temperatures were 104°F (40°C) and pressures 57 psig (4 bar). The 1⁄8-in.-thick glass-filled PTFE gaskets didn’t consistently provide a tight seal. So, the plant applied mastic filler to treat damaged flange surfaces as a stop-gap measure.
Gylon Epix 3504 was installed in December of 2017; it performed successfully without the need for flange treatments or special installation handling. Its enhanced compressibility fills the gap of imperfect flanges. It performed well until its removal in September of 2018 when the pump mechanically failed for a reason not related to the gasket. The acid processor is adding Gylon Epix to its approved materials list because it worked without the need for mastic, was flexible and easy to handle, and performed with zero leaks.
Terephthalic acid manufacturing. A southeastern U.S. producer of terphthalic acid (TPA) was experiencing leaks with traditional glass-filled PTFE sheet gaskets on a pressure vessel operating at 230°F and 60 psig that has a 60-in. × 10-in. rectangular gasket joint opening. Large rectangular joints can have uneven surfaces due to warpage of the cover. In July of 2018, Gylon Epix 3504 was installed and is still in service as of September 2019 and performing well. The company has accepted the product into its system and is re-ordering.
The original article can be found here and was written by Jim Grago, PE, a principal applications engineer for Garlock.
Gallagher Fluid Seals is an authorized distributor of Garlock. For questions about products or to see if Gylon Epix is the right fit for your application, contact our engineering department.
Original content can be found on Parker’s Website and was written by Ben Nudelman, Market Development Engineer, Chomerics Division.
Form-in-place EMI gaskets, also known as FIP EMI gaskets, is a robotically dispensed electromagnetic interference (EMI) shielding solution that is ideal for modern densely populated electronics packaging.
The most important distinction of form-in-place EMI gaskets is that they were developed for applications where inter-compartmental isolation is required to separate signal processing and/or signal generating functions.
Simply put, form-in-place gaskets are meant to reduce “noise” between cavities on a printed circuit board (PCB) or in an electronics enclosure.
In addition, form-in-place gaskets provide excellent electrical contact to mating conductive surfaces, including printed circuit board traces for cavity-to-cavity isolation. Parker Chomerics form-in-place gasket materials are known as CHOFORM.
7 reasons why form-in-place EMI gaskets can be an ideal choice
Small form factor – form-in-place gaskets can be dispensed in smaller bead sizes than most traditional EMI shielding gasket solutions, 0.018” tall by 0.022” wide.
Excellent adhesion – 4-12 N/cm adhesion on prepared surfaces such as machined metals, cast housings, and electrically conductive plastics.
High shielding effectiveness – Parker Chomerics CHOFORM materials can provide more than 100 dB shielding effectiveness in the 200 MHz to 12 GHz frequency range.
Quick programming – Because form-in-place EMI gaskets are robotically dispensed, a standard CAD file can be used to program the dispensing system and quickly map out the dispensing pattern.
Complex geometries – The positional tolerance of the gasket can be held to within 0.001” and is able to follow very complex geometries including sharp turns, corners, and serpentine patterns. Other gaskets such as die cut sheets or o-rings manufacture and/or fabricate into such shapes and patterns.
“T” joints – Traditional extruded gaskets are difficult to mate at intersections or “T” joints. The robot dispensing systems produce reliable junctions between bead paths to provide continuous EMI/EMC shielding and environmental sealing.
Integrated solutions – CHOFORM technology combined with a Parker Chomerics supplied metal or conductive plastic housing provides an integrated solution ready for the customers’ highest level of assembly. This approach requires no additional assembly or process steps for the installation of gaskets and/or board-level auxiliary components.
Form-in-place EMI gasket limitations
Large form factor enclosure sealing that can accommodate a groove. For larger areas such as machined covers that can accommodate a gasket groove, other EMI shielding solutions are better suited. In most applications, conductive elastomers such as the CHO-SEAL product line by Parker Chomerics will provide better shielding and sealing. Form in place gaskets can be dispensed in bead sizes only as large as about 0.062” tall x 0.075” wide.
Enclosures requiring submersion or durable weather sealing. Because of the small form factor, FIP gaskets will not meet stringent environmental sealing requirements such as IP 67 or higher. While silicone-based, the material is better at preventing dust and environmental moisture from entering an enclosure. FIP gaskets can be paired with additional sealing gaskets for enhanced weatherproofing.
Gallagher Fluid Seals is an authorized distributor for Parker. For more information about their products, including o-rings or their various compounds, contact Gallagher Fluid Seals today.
Enhancing the surface profile can improve sealing capabilities, extending the functionality of aging piping systems in chemical plants.
There are many aged and aging process plants in operation today. In fact, many of the processing plants for power, chemicals, oil, etc., have been in service for more than 50 years. And while the piping itself may remain intact, their bolted flange gasket joints and connections are becoming misaligned, corroded and damaged due to repeated handling, chemical exposure and thermal cycling. This can lead to costly ruptures that may result in millions of dollars in damages, downtime, noncompliance penalties, irreparable environmental impact and litigation.
There is a solution that can extend the life of aging piping systems, preserving their functionality: raising the surface profile on polytetrafluoroethylene (PTFE) gaskets. This design modification can prevent leaks, spills and other releases in chemical processing plants by reducing and managing the contacted area of the gasket, thus achieving and maintaining a strong seal.
A Brief History of Gasket Technology
Traditionally, gasket thickness and sealability always involved a performance tradeoff. One could use 1/16-inch-thick (1.6 millimeter) gaskets when flanges were in good condition, achieving a tight seal with reduced creep.
However, when the flanges had bad or misaligned surfaces, the seal integrity was degraded.
In those instances when the flanges are in poor condition (or if the shape of the flange condition is unknown), one would choose a 1/8-inch-thick (3.2 mm) gasket. The reason? A user does not want to risk installing a thinner gasket and discover that it does not seal properly, which then requires a timely and costly uninstall and reinstall. However, the thicker gaskets do not seal as well as their 1/16-inch counterparts when placed under comparable load. Additionally, with the thicker gaskets, creep is higher, requiring re-torque.
To address the limitations of both gasket options, the ideal gasket should combine the creep resistance of a 1/16-inch gasket with the compressibility and conformability of a 1/8-inch gasket—easier said than done.
Historically, gaskets have not always been forgiving, easy to use or simple to remove. Yet technology has evolved, allowing sealing products to be engineered and designed to optimize the work that is put into them, delivering a tighter, more durable seal.
The approach is one that does not focus on the gasket thickness but rather its surface profile. The results produce gaskets that reduce leaks, spills and other releases from piping systems, including those of aging chemical plants.
Raising the Gasket Profile
The concept of using surface profiling to reduce area and increase stress is found in many products, such as running shoes and car tires. Reducing the contact area while maintaining a given amount of compressive force results in increased stress. In the case of shoes or tires, this stress provides traction. In the case of gaskets, traction or friction between a gasket and a flange face is critical to holding internal pressure. If the downward force created by the fasteners in a flange is evenly spread over a larger area, the created stress contributes to making a seal more effective. This approach enables the aging piping system to maximize its sealing potential.
Impact on Raising Gasket Profile
Surface profiling positively impacts gasket technology in five key areas: compressibility, pressure resistance, scalability, load retention and dimensional flexibility.
Compressibility is a critical functionality of gaskets, as it represents the ability of the gasket to conform to the surfaces that it seals. Adding raised features to the surface of a gasket directly impacts compressibility by reducing the contact area and increasing the resulting stress.
When flange surfaces are worn, pitted or scratched—such as those in aging piping systems in chemical plants—it can be cost prohibitive and nearly impossible to repair/replace the flange to a “good as new” condition. The more compressible the gasket, the better chance of producing an effective seal with the flanges. Continue reading Raising the Gasket / Surface Profile in Aging Systems→
The search for the ideal Polytetrafluoroethylene (PTFE) gasket has been elusive. Competing applications and workplace variables have led to the creation of myriad solutions, yet none that has proven fully adaptable and appropriate for universal adoption.
Garlock Sealing Technologies considered this to be a critical yet entirely solvable shortcoming. And it is against this backdrop that in 2016, they set out to compile a comprehensive list of attributes for the ideal PTFE gasket — a wish list, as it were — in order to build a better gasket.
Working with a third-party survey development company, Garlock developed an exhaustive questionnaire that probed every aspect and functionality of PTFE gaskets, testing and adjusting the questions until they had a workable, finalized version.
Using this final questionnaire, Garlock conducted extensive interviews at 15 major chemical processor companies, speaking with 20 engineers responsible for process operations, projects, maintenance and reliability. The goal was simple: to discover the ideal characteristics and their relative importance that engineers sought in a PTFE gasket.
After several months of data collection, Garlock analyzed the feedback and noted the most popular responses:
28% of respondents said that they struggled with how different gaskets required different compressive loads and how to ensure that those gaskets had been installed properly
21% expressed frustration with the creep properties of PTFE gaskets
21% desired a gasket that seals with less compressive load
14% expressed frustration at the installation inconsistencies of their fitters
14% expressed frustration with leaking, especially after a successful installation and start-up
From those answers, Garlock drew the following conclusions, representing the most desirable and essential PTFE gasket characteristics:
Seal: Seals easily
Installation and assembly: Forgiving of poor installation or assembly practices
Forgiving: Forgiving of poor flange conditions
Retention: Maintains a seal after installation
Flexible: Can be used in a broad range of services to avoid user confusion and reduce inventory
Introducing: GYLON EPIX
Garlock used this feedback in developing a next generation PTFE gasket — GYLON EPIX. Featuring a hexagonal surface profile, GYLON EPIX offers superior compressibility and sealing for use in chemical processing environments. Its enhanced surface profile performs as well or better than existing 1/16″ or 1/8″ gaskets, allowing end-users and distributors to consolidate inventory, lower the risk of using incorrect gasket thicknesses and reduce stocking costs.
GYLON EPIX checks off the most desirable gasket attributes:
Installation and assembly: Even distribution of the bolt load over the contacted area of the gasket during the assembly process
Retention: Retention of the bolt load administered at assembly
Seal: Efficient translation of bolt load to sealing performance
Forgiving: The ability to perform in imperfect flanges and installation conditions
GYLON EPIX with its raised, hexagonal profile allows it to perform the job of both traditional 1/16” and 1/8” gaskets. It accomplishes this by combining the bolt retention of the former with the forgiveness for bad flange conditions of the latter, a truly innovative feature for PTFE sheet gasketing. Continue reading The Ideal PTFE Gasket for Tough Applications – GYLON EPIX→
Recent gasket failures in flanged joints of High Density Polyethylene (HDPE) piping.
HDPE piping joints are typically thermal fusion welded joints, but flanges may also be used. When flanges are used, an HDPE flange adapter with a metal backing ring is fused to HDPE piping, as shown in Figure 1. The HDPE flange adapters are used to connect to other flanged fittings, such as valves, elbows, tees, etc., with gaskets inserted between the flanged fittings.
In 2018, two HDPE flange adapter gaskets on two different valves that were part of an underground fire suppression system at a Department of Energy (DOE) nuclear facility in Amarillo, TX failed, causing several weeks of unplanned interruptions to nuclear facility operations. Fire suppression water was isolated to two nuclear facilities, requiring nuclear operations to be paused and fire watches to be established. Both couplings were installed by the same contractor and had been in service for approximately eight years. Both flanges were correctly torqued to 160 foot-pounds with no indication of the necessary re-torque. The initial failure of the gasket caused a low flow, high-pressure leak that was not detected for some time. With the system pressure operating at approximately 150 pounds per square inch (psi), the orifice created by the failure of the gasket(s) between the two flanged faces created a water jet, which eroded the metal valve flange and bolts.
Because HDPE will relax after the flange bolts are torqued, a re-torque after 24 hours is required. Even after the bolts are re-torqued, the face stresses drop to 400–600 psi. The lower face stress reduces the friction for maintaining the gasket in between the flange faces. The challenge is finding a gasket that can handle pressures that may exceed 200 psi, gauge (psig), but also seal well at relatively low stresses.
Due to the many inquiries from customers and engineering firms for gasket applications involving HDPE piping, Garlock, a gasket manufacturer, published a memo in January 2017 recommending using either GYLON® Style 3545 or MULTI-SWELL™ Styles 3760/3760U as the best options for HDPE flanges, even though the available compressive loads are lower than recommended. The reinforced gasket material of the GYLON and MULTI-SWELL has proven to prevent the internal water pressure from damaging the gasket under low-compression loads.
Other gasket manufacturers may have similar gaskets that will work for this application. It is important for the Design Engineer to work with the gasket manufacturer to properly specify the correct gasket.
Recommendations to HPDE Piping and Flanged Joints
When using HPDE piping with flanged joints, ensure that the flange bolts are re-torqued at least 24 hours after gasket installation.
When evaluating gasket material, be sure to include any surge pressure that could be caused by opening valve and starting pumps. Also, include any additional design/safety factors in your gasket calculation. And, directly work with the gasket manufacturer in making a selection.
Rare and Ultra-Pure Resources Present Unique Challenge to Finding Appropriate Low Temp Gasket
Modern technology often requires rare or ultra-pure materials that can only be handled or obtained within extreme environmental conditions. These same conditions present unique and hazardous difficulties when transporting or utilizing these resources. Resources such as liquid oxygen, nitrogen, or argon; all of which are classified as “industrial gases” are handled well below the normal temperature ranges that every-day liquids exist; ranging as low as -195.8°C (-320.4°F). This often makes it a challenging task to find a low temp gasket to fit the specifications for the application.
As an example, let’s look at argon; an important gas used in Welding, Neon Lights, 3D Printing, and Metal Production, just to name a few. It is far more economical to house and transport argon in its liquid state. However, it must be held at an astonishingly low -185.9°C. Fitting the pipes together and maintaining a seal in a cryogenically engineered system that the liquid argon is housed presents unique difficulties. Argon gas is colorless, odorless, tasteless, and can irritate the skin and the eyes on contact. In its liquid form it can cause frostbite.
There are important considerations that should be taken into account when installing gaskets for dangerous extreme low temp materials.
Proper Gasket Installation
Many gasket materials can become brittle, crack, shrink, and blow out when exposed to extreme cold – not something you want to happen at any time, let alone with a liquid that can freeze you into a meatsickle. So, proper installation is also key. During installation, it is important that all parts are dry, the installation is done at ambient temperature, and then re-adjusted with changes in temperature.
Any mechanical seal that is sealing a product with a temperature below 0 degrees Celsius is given the name “Cryogenic”. Liquefied gases (LNG), such as liquid nitrogen and liquid helium, are used in many cryogenic applications, as well as hydrocarbons with low freezing points, refrigerants and coolants.
When selecting a low temp gasket or sealing material to be used in cryogenic service, it is important that the material can withstand cryogenic temperatures.
Low temperature applications are found across many industries, these include:
Garlock GYLON® and KLINGER SLS/HL
Good gasketing materials that can withstand the frigid cold and are pliable in the requirement to maintain the seal would be the Garlock GYLON family of gaskets (PTFE, capable of -450°F (-268°C)) or the Klinger SLS/HL, which is made of flexible graphite and can withstand -400°F (-240°C)
As with all gasket applications, environmental conditions should be considered in conjunction with the functional requirements of the device. Though there are limited options to solve extreme low temp gasketing challenges, Gylon and Klinger can be a good fit for your application.
Portions of the original article were written by Michael Pawlowski and Sylvia Flegg of Triangle Fluid Controls Ltd. The article can be found on Empowering Pumps website here.
How this feature can improve performance and efficiency with gaskets
Gaskets have always been part of industrial production. However, gaskets have not always been forgiving, easy to use or simple to remove. What if the sealing products were designed to optimize the work put into them? What if the design had a level of intelligence built in? What if the design could make up for equipment damage? When used properly, enhanced surface profiles for gaskets can reduce leaks, spills and other releases that can damage the environment, put people at risk, result in fines and lead to costly downtime.
Using surface profiling to reduce area and increase stress is found in everyday life, from the soles of running shoes to the treads on vehicle tires. Reducing the contact area while maintaining compressive force results in increased stress. In the case of gaskets, traction or friction between a gasket and the flange faces is critical to holding internal pressure. If the downward force created by the fasteners in a flange is diluted or spread over a larger area, the overall stress is reduced.
Adding raised features to the surface of a gasket to reduce contact area and increase stress also tends to impact compressibility. Compressibility represents the ability of the gasket to conform to the surfaces it is being used to seal. Flange surfaces usually show signs of wear, pitting, scratches or other defects. It is cost-prohibitive to make two mating flange faces smooth and flat enough to seal without a gasket. The more compressible a gasket is, the better chance the user has of attaining an effective seal.
Compressibility also impacts the amount of pressure exposure on the gasket. When a flange assembly is pressurized, the internal media pushes outward on the inner diameter of the gasket. The thinner a gasket becomes, the less outward force it sees from internal pressure. This is referred to as improved “blowout resistance.” Unfortunately, one common error made when a gasket blows out is to replace it with a thicker gasket. This puts more gasket surface in the pipe or vessel for the internal pressure to act on.
To create an effective seal, there are two functions the gasket must accomplish.
Have you ever received the dreaded 2 a.m. call from plant staff saying that things are at a standstill – production is down?
You arrive at the plant, walk through the parking lot, coffee in hand, and head to the locker room. When you come out on to the plant floor, there are several people staring at you with a look of panic on their faces as steam or process chemical sprays from a pipe flange.
You think to yourself “didn’t we just replace that gasket?”, or perhaps “we should have replaced it during the last shutdown but chose not to because of time constraints or cost cutting.”
If this scenario is new to you, you are lucky and you can go back to sleep… the 2 a.m. call was a wrong number. If it’s not new to you, this means you are most likely a Plant Supervisor, Maintenance Manager or Plant Personnel in some capacity.
Roll up your sleeves, grab your torque wrench and let’s get to work!
If I had a nickel for every time someone asked me, “How long will my gasket last?” I would be a rich man. As you can probably guess, “How long will my gasket last?” is a loaded question to which the practical, factual, and political answer is… an Application Engineer’s nightmare!
A gasket may last 5 years, or it could last 20 years. I cannot give you an exact date or lifespan of a gasket; however I can give you some insight into factors that will give your gasket the best chance at a long and prosperous life between the flanges.
The GYLON Style 3504 gasket is made of PTFE with aluminosilicate microspheres. It is designed for use in moderate concentrations of acids, caustics, hydrocarbons, refrigerants, and more.
It provides a tight seal, improved performance over conventional PTFE, reduced product loss and emissions, reduced creep relaxtion, excellent bolt torque retention, it doesn’t burn, will not support bacterial growth, plus many more benefits.
Food Processing – Fried Snack Foods
A major diversified food & beverage manufacturer, with facilities located in all regions across the globe.
The customer had persistent problems when sealing hot oil applications on its bulk snack food fryers across several production sites. Build-up of polymerised vegetable oil on the flanges caused unsightly mess, maintenance complications, financial implications, and posed a significant fire risk.
As well as ensuring that the sealing material was compliant to FDA and EN1935 standards, the challenge was to ensure that the gaskets would perform well under the difficult conditions presented by the high oil temperatures. Additionally, because the production line was also subject to regular and aggressive cleaning cycles, the gasket material was required to be compatible with other aggressive chemicals across a broad pH range.