ePTFE
- July 05, 2023
Since 1958, Gore has developed products that improve lives. At the center of these solutions is polytetrafluoroethylene (PTFE), a polymer with exceptional properties like high tensile strength, a low dielectric constant, UV resistance and many more. In 1969, the possibilities for PTFE expanded with Bob Gore’s discovery of expanded PTFE, or ePTFE.
In the years since, Gore has developed unparalleled expertise in manipulating ePTFE and other fluoropolymers. Gore's engineers can change a material’s structure, shape, thickness and surface geometry, then pair it with complementary materials to provide the performance qualities required by the application and the customer. The resulting product can be strong or permeable, rigid or flexible, thin or thick — with many additional combinations of properties that can be applied to meet the end use requirements.
Since its very founding, Gore has been passionate about solving the complex challenges of their global customers. From the first suggestion of a product need, to its delivery to market, this passion is apparent in everything Gore does.
- Curiosity: From keeping water off a person’s skin to preventing leaks from happening in chemical containers, Gore listens to their customers and analyze the challenges to determine the underlying problem.
- Competency: Gore determines how they can apply their expertise in fluoropolymer science to deliver solutions that are valued and differentiated from the competition.
- Commitment: Gore rigorously tests their products to ensure they deliver failure-free performance and suit their customers’ needs and applications, the first time and every time.
- March 24, 2023
Gore Joint Sealant and Gore Gasket Tape Series 500
Created more than 40 years ago, Gore Joint Sealant was the first form-in-place gasket. It was and still is a great sealing solution for steel flanges with large diameters, irregular shapes, or rough/pitted surfaces. It forms a thin yet strong seal when compressed and works in applications where bolt loads are low.
With a reliable, easy install and being a cost-effective sealing method, it's become standard seal for MRO applications all over the world. Installing it is very easy, too: Simply peel off the adhesive backing, apply it to the
- September 22, 2021
Not all applications are created equal, and when the application is especially demanding, one, at times, must consider different solutions.
Such is the case regarding air operated double diaphragm (AODD) pumps. Typically, applications associated with this type of pump involve chemical compatibility 0.0 issues, abrasive element concerns, or a combination of the two.Some examples include:
- Mining applications involving slurries of acids and solids
- Paint and coatings applications including chemical compatibility issues relating to solvents/additives and abrasion from pigments
- Ceramics
- Chemical processing
- Pulp and paper
- Similar applications using process media with abrasive solids
- September 08, 2020
Fiber Reinforced Plastic (FRP) pipes and flanges are increasingly used in the oil and gas industry where metal is simply too heavy and expensive. In addition to cost pressure, the need for lightweight chemically resistant materials are also driving the use of fiberglass pipes and flanges. Innovations in FRP flange design coupled with improvements in manufacturing technology have allowed FRP piping to be used in even more demanding applications. However, these demanding applications have added challenges for sealing the bolted flange connections.
More aggressive media and higher internal pressures have pushed the limits of the commonly used rubber gasketing materials, such as Nitrile Butadiene Rubber (NBR), Ethylene Propylene Diene Monomer (EPDM), or neoprene. Obtaining a reliable seal in FRP flanges using conventional gasketing materials has become more difficult.
Fiberglass pipes are generally known to have strength limits and a lower pressure resistance, making sealing fiberglass flanges difficult. Gore solved this problem with its patented expanded polytetrafluoroethylene (ePTFE) gasket, specifically designed to seal flanges at low stresses. This solution was successfully demonstrated in a multistage testing procedure conducted in cooperation with a globally leading manufacturer of anti-corrosive fiberglass pipe systems.
- May 19, 2020
Attention: When installing GORE Gasket Tape Series 1000 in joints with multiple (2 or more) gaskets compressed with a single set of bolts or clamps, see the installation supplement “Installation on Joints with Multiple Gaskets,” for additional mandatory instructions.
1. Select the size
GASKET WIDTH
Select the gasket width that provides enough material to align the gasket tape flush with the inner and outer diameter. Ensure full coverage of the glass surface. Excess material may exceed the outer diameter.
GASKET THICKNESS
Most applications require a base layer of 6 mm (1/4") tape, which can accommodate deviation up to 1.5 mm (1/16") without shimming. Applications with deviation up to 2.3 mm (0.090") can utilize 9 mm (3/8") tape without shimming.
SHIMMING
To effectively seal flanges with deviations beyond the maximum for the base layer, a shimming process is recommended. Use of 3 mm (1/8") GORE® Series 1000 shim tape as a shim layer will accommodate an additional 1.5 mm ( 1/16") of flange deviation. Ensure the shim layer has the same width as the base layer.
2. Determine a Torque Value
To achieve a reliable seal, adequate gasket stress must be applied during installation.
Typical minimum stress to seal values for GORE Gasket Tape Series 1000 are:
- 6 mm (1/4"): 14 MPa (2,030 psi)
- 9 mm (3/8"): 18 MPa (2,610 psi)
Perform an engineering calculation to determine the torque value for your specific application.
Industry guidance is available, for example in ASME PCC-1 Guidelines for Pressure Boundary Bolted Flange Joint Assembly, and EN 1591-1 Flanges and their Joints - Design Rules for Gasketed Circular Flange Connections - Part 1: Calculation.
However, ASME PCC-1 does not include glass-lined steel specialties. Therefore, it is advised to contact the equipment manufacturer for an adequate torque recommendation.
- March 10, 2020
ePTFE Gasket Tapes for High Chemical Resistance
The connections to shell and tube heat exchangers pose immense challenges for the seals that are used because of both the chemically aggressive media and the frequent temperature load changes. Despite its excellent chemical resistance,polytetrafluoroethylene (PTFE) is not typically suitable as a sealing material in this case because the creep tendency of this material jeopardizes a reliable seal.
Shell and tube bundle heat exchangers generally include not only several connection pieces but also a shell cover flange with a significantly larger nominal diameter.The shell cover flange creates the seal to the tube bundle flange, which then seals the shell flange. These connections are subjected to the full operating pres-sure and test pressure of dozens of bar and seal it from the environment. Oftentimes the tube bundles are arranged in several passes that are channeled by the use of partition plates. This requires a seal at
- March 14, 2019
A newly developed gasket tape made by Gore - of expanded polytetrafluorethylene (ePTFE) is specifically designed to address the challenges of creating reliable seals in large glass-lined steel equipment.
Equipment made of glass-lined steel is used when manufacturing or processing aggressive chemicals such as aniline derivatives and sulphuric or hydrochloric acid. The Achilles heel of such systems is the gaskets needed to seal the joints between components. Exposure to aggressive media causes the seals to degrade overtime, resulting in damage to equipment and posing a health risk to operators. Replacing the seals costs a great deal of time and effort, with a corresponding drop in production output.
A newly developed gasket tape made of ePTFE (expanded polytetrafluorethylene) is specifically designed to address the challenges of creating reliable seals in large glass-lined steel equipment.
Operators of chemical plants choose sealing materials according to a wide range of criteria such as process medium, flange type, sealing performance, pressure and heat resistance, cost and longevity. Other important selection criteria include time required for installation and inventory management. And, of course, a plant operations prior gasket experience weighs in as well. Gaskets for glass-lined-steel equipment are safety-relevant parts because their failure can endanger human lives and/or harm the environment, but they are often treated for administrative purposes as C-class items, that is, parts of minor significance.
This classification doesn’t reflect the true importance of these sealants. There is a need for more explicit regulations to supplement the general legislation pertaining to occupational health and safety and the handling of hazardous substances. The introduction of a European-wide regulatory basis for establishing detailed, standard processes would be welcome, for instance with respect to approval procedures and safety. As things stand today, companies are obliged to find their own compromise between varying sets of requirements. These include compliance with EU-wide and national directives concerning environmental protection and occupational health and safety. At the same time, companies are making efforts to augment the reliability of their products, simplify inventory management and installation processes, and reduce downtime and overall costs. An added factor in both cases is specific process requirements with respect to temperature, pressure and media.
SEALING CHALLENGES
One particular challenge is that of choosing the right sealant for glass-lined steel systems, because these involve the use of aggressive media such as aniline derivatives and sulphuric or hydrochloric acid under demanding conditions. Glass-lined steel presents the advantage of being highly resistant to corrosive and/or abrasive media. Other characteristic features of this material are its smooth surface, which is easy to clean due to its low adhesion properties, and its biologic and catalytic inert behaviour. Nonetheless, it can be difficult to achieve reliable seals in glass-lined steel equipment. This is because the glass lining is more brittle than the metal, and can therefore split or splinter if handled incorrectly. As a result, the gasket load that can be applied to the seal is lower than that for an all-steel flange. Consequently, care must be taken to limit the pressure applied when installing gaskets between interconnecting parts of the system.
Another problem is that of achieving a reliable seal if the flange surface is uneven or has surface deviations. Once the glass lining has fused, its surface cannot be reworked. The challenges posed by these characteristics of glass-lined steel, combined with the exposure to aggressive chemicals and high temperatures, must be met by the chosen sealant. In practice, these difficult conditions often lead to premature sealing failure and a greater risk of corrosion. The further consequences of sealing failure include leaks and uncontrolled emissions, damage to equipment, high replacement and repair costs, production losses, unplanned maintenance and downtime, and potential risks to employees’ health and safety.