Spiral Wound Gaskets – The Durlon Difference!

By: Chett Norton, C.E.T

November 3, 2015

Spiral wounds gaskets ( SWGs) are a great multi-purpose gasket used in piping systems throughout the world. They are somewhat inexpensive, durable and in most cases readily available (pending metallurgical and filler requirements). The good thing about SWGs is that they can be used in all pressure classes, 150# up to and including 2500#. The design of spiral wound gaskets makes them blowout resistant and well accepted within the industry as a “Fire Safe” type of gasket.

Are all Spiral Wound Gaskets the Same?

The general assumption with spiral wound gaskets is that they are all the same. This is both true and false. Now I am going to play devil’s advocate on this. The reason I answered true is because all standard size spiral wound gaskets are typically manufactured to ASME B16.20, which is a dimensional manufacturing standard covering Metallic Gaskets for Pipe Flanges – Ring-Joint, Spiral Wound, and Jacketed (Gaskets). Also included in the publication of this standard are grooved metal gaskets with covering layers, otherwise known as Kammprofile gaskets. The most recent revision was published in 2012, hence, the current standard reference of ASME B16.20-2012. This standard covers gasket dimensional sizes in accordance to ASME B16.5 or B16.47 pipe flanges as well as the construction, metal joining, centering ring, inner ring, gasket compression and marking (general, pressure class and colour code) of the gaskets.

However, to answer the direct question, “Are all spiral wound gaskets the same?”, my answer would be no they are not. The reason for this is that things such as metal quality, filler quality (density, grade, thickness) and whether or not the gaskets were made on machines that control both pressure and tension on the gasket winding while being manufactured, ultimately control the final quality of the spiral wound gasket.

Spiral Wound Gasket Identification

SWG Colour Chart

Spiral wound gaskets at times can seem to be very confusing with so many colours and stripes on them. However, it should be noted that using the ASME designation colour chart is pretty straight forward. The paint colour code system refers to the gaskets’ outer edge of the centering ring and the vertical stripes painted on the outer edge of the centering ring. The solid outer edge colour indicates the metal winding used and the vertical stripes indicate the filler used (see applicable charts below). Please note that the inner material should also match the winding material as noted in ASME B16.20-2012, unless specified by the user. For outer rings, the epoxy colour on the face of the rings is only brand specific, though some epoxies are more resistant to chemical attack and general atmospheric degradation. If the material of the centering ring is anything other than carbon steel, it will also be stamped on the ring.

Spiral Wound Gasket Constraints

The limiting factor in most cases for spiral wound gaskets is temperature. In general, it is the filler material that creates this limit.

Example:
For a 2” 300/400/600 spiral wound gasket construction of 304SS winding (760°C/1,400°F) and flexible graphite filler (510°C/950°F), the maximum temperature will be 510°C/950°F. This is governed by the flexible graphite filler even though the 304SS winding strip is rated to 760°C/1,400°C.

There are few exceptions to this rule and one of them is our Durlon® SWG DRI-ETG gasket. This gasket utilizes Durlon® HT1000® (Phlogopite Mica) material on both the ID and OD of the sealing element, while using super inhibited graphite in the middle of the sealing element for enhanced sealing capabilities. These layers of Durlon® HT1000® act as a heat shield or anti-oxidation layer and allow the gasket to seal up to 1,000°C/1832°F, where normal inhibited graphite is limited to approximately 565°C/1,050°F.

 

Benefits of Durlon® Spiral Wound Gaskets:

  • All Durlon® SWGs in Class 150 & 300 are designed to seal at lower than standard loads, thus making it a low stress sealing gasket. Therefore you do not need to stock both standard and low stress sealing types of gaskets and can consolidate your inventory levels.
  • All gaskets have been manufactured with inhibited graphite since January 2015. Inhibited graphite performs much better than standard grade. It allows you to extend your operating temperature to 1,050°F vs. 950°F. The rate of graphite oxidation at the higher temperatures is much lower which leaves more graphite to seal your application.
  • All metals on gaskets made at Triangle Fluid Controls (TFC) are sourced from North America and the UK.  This gives full traceability of materials as we provide MTRs for metal in the gasket windings and PMI testing for both the inner and outer rings (non-carbon steel). TFC can also provide this documentation free of charge.
  • Large in stock inventory of specialty metals: 316Ti, 317SS, 321SS, 347SS, Hastelloy C276, Alloy 20, Alloy 400 (Monel), Titanium, Alloy 2205 (Duplex) Alloy 600/625/800 and many others. This allows for a short turnaround on non-standard gasket materials. In some cases next-day delivery for critical shutdown requirements.
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  • Fillers available: Flexible Graphite (standard, inhibited & super inhibited grades), PTFE, Mica, HT1000® and Durlon® ETG (combination of super inhibited graphite with HT1000®). This availability of fillers allows us to seal basically any need or requirement from aggressive chemicals to high temperature applications found in today’s industries.

 

Spiral Wound Gasket Facts

  • All gaskets should be supplied with an inner ring, unless the purchaser or end user specifies otherwise, as per ASME B16.20-2012 to help prevent inward buckling (see image).
  • All PTFE filled SWGs shall have inner rings as per ASME B16.20-2012.
  • For all other filler materials, inner rings shall be supplied in spiral wound gaskets in the below sizes/classes. (Higher bolt loads generated by the larger bolt diameter/quantity decrease the risk of inward buckling):NPS 24 and larger in Class 900
    NPS 12 and larger in Class 1500
    NPS 4 and larger in Class 2500
  • Centering rings are not designed to be used as compression stops.
  • Centering rings are carbon steel by default (epoxy coated or zinc electroplated to prevent corrosion), unless otherwise specified by the purchaser or end user. Carbon steel will not be stamped on the outer ring whereas materials such 304SS or 316SS will be.

Final Thoughts

In closing, spiral wound gaskets are still considered to be an existing technology or simple commodity. However, based on proper metallurgy selection and filler materials it can be a very innovative, engineered solution to today’s modern sealing challenges. So the next time you have to replace a gasket and you are unsure or have questions, ask yourself WWTGGD (What would the Gasket Guru Do?). You could also fill out the Gasket Application Data Form or call us (toll free) 866-537-1133.
 

 



Triangle Fluid Controls Bantam Jr Bulls

The Triangle Fluid Controls Bantam Jr. Bulls entered the 6th annual Prince Edward County Minor Hockey Association, Milk Tournament, October 23rd – 25th with a .500 record on the regular season to date.

The TFC Jr. Bulls first game featured a matchup with the host, Prince Edward County Kings, on Friday, October 23rd. The TFC Jr. Bulls came out flying and put up a dominating performance winning 8-0. The second match of the tournament for the TFC Jr. Bulls saw them facing the well-rested Mount Brydges Cougars on Saturday, October 24th. In a tight match from start to finish, the TFC Jr. Bulls were downed 3-1. Twelve hours later in their third and final match of the round robin portion of the tournament the TFC Jr. Bulls faced Valley Storm needing at least a tie game to advance to the finals on Sunday. In a dramatic finish, the TFC Jr. Bulls scored with under 5 seconds left in regulation to seal the victory in a 7-6 barn burner.

Finally, on Sunday the TFC Jr. Bulls were up against the Mount Brydges Cougars who had beat them a little more than 24 hours earlier in what was expected to be a tight game. The TFC Jr. Bulls jumped out to a 2-0 lead only to have Mount Brydges come back with two of their own to tie it at 2-2. The Jr. Bulls went up 3-2 and never looked back. They put the game out of reach with an empty net goal late in the third period to seal the victory and the championship 4-2.

Triangle Fluid Controls Ltd. would like to extend our congratulations to the players and team staff on a well-deserved title!

By: Chett Norton, C.E.T & Alison Brent

Thursday, September 10, 2015

In the gasket industry there are a multitude of tests performed on materials that will supposedly help the end user make an educated decision on which material to use based on specific application criteria. However due to the lack of gasket property knowledge, what often ends up happening is that the end user becomes more confused, running the risk of choosing an incorrect material and causing untimely leaks or even unsafe gasket blowouts.

This article is intended to shed some light on four commonly misinterpreted and misunderstood gasket material tests: Flexibility (ASTM F147); Tensile Strength (ASTM D4745, ASTM F152); Sealability (ASTM F2378); and Maximum Pressure.

ASTM F147 – Standard Test Method for Flexibility of Non-Metallic Gasket Materials

Durlon 9000 Flexibility Test

A sample of Durlon 9000 being checked for flexibility.

This test method measures the gasket material’s Flexibility both transverse and longitudinal to the grain orientation. This test can also determine quality of the gasket material by determining the product’s Flexibility factor.

In this test, several “dog bone” shaped samples (based on the ASTM F147 standard) are cut in both transverse and longitudinal orientations. These samples are are placed in a conditioning oven at 100˚C (212˚F) for an hour then cooled to room temperature in a desiccator. The test material’s thickness is determined with a micrometer and recorded. The test material is firmly held at one point on a circular mandrel (ranging in diameter from 4.8mm to 101.6mm, starting with the largest diameter) and forced slowly to contact 180˚ of the full diameter. This procedure is repeated using decreasing mandrel diameters on a new sample until a failure occurs. A failure is considered to be any cracks, breaks, or surface separations at the end of the Flexibility test. When a failure occurs the mandrel diameter is recorded.

A Flexibility factor can be calculated by taking the Minimum Diameter divided by the Original Thickness. It is important to understand that when looking at the Flexibility factor the lowest possible value is considered a positive result. For example, Flexibility values are a lot like golf scores, meaning the lower the score, the better. Therefore, with Flexibility a value of 4 would be more flexible than a value of 10.

Tensile Strength (ASTM D4745 & ASTM F152)

Durlon 9000 Tensile Test (ASTM F2378)

A sample of Durlon 9000 being pulled during the Tensile testing process.

 

At Triangle Fluid Controls we do 2 different types of Tensile testing using ASTM D4745 and F152 meaning we test both little “dog bones” and big “dog bones”. The test used is dependent on the type of material being tested, i.e. fiber, PTFE, and graphite. These “dog bones” are predetermined test specific shaped samples. Tensile testing is a quality control test by measuring the strength of the product, which in turn, determines the conformance of the manufacturing process. It should be noted that Tensile strength is not equivalent to the maximum pressure rating of the product, but more of a standard internal QA check.

ASTM D4745 – Standard Classification System and Basis for Specification for Filled PTFE Molding and Extrusion Materials

The ASTM D4745 Tensile test involves cutting material both transversely and longitudinally (conditioned based on sample type). These samples are then placed and clamped into our Tensile machine with an extensometer also attached to the sample. An extensometer is used to determine the strain measurement of the material under stress. The machine is then set up and parameters of the sample are imported. The machine is then started and runs until a failure occurs (any cracks, breaks, or surface separations at the end of the test). The results are recorded in psi and percent elongation.

ASTM F152 – Standard Test Methods for Tension Testing of Nonmetallic Gasket Materials

The ASTM F152 Tensile test is similar to the D4745 Tensile test except this test only involves samples to be cut transversely (conditioned based on sample type) and no extensometer is attached. These samples are then placed and clamped into the Tensile machine and the test is performed.

ASTM F2378 – Standard Test Method for Sealability of Sheet, Composite, and Solid Form-in-Place Gasket Materials

This test method is suitable for evaluating the leakage rate, sealing properties and characteristics of gasket materials under a load pressure at room temperature (21-30˚C/70-86˚F).

This testing process involves placing a cut sample (conditioned-based on sample type) using the ASTM F2378 specified die dimensions in between 2 flat steel platens. A seating load of 4,640 psi is applied and nitrogen is introduced into the center gasket cavity at a pressure of 580 psi. A timer is set for one hour, forty-five minutes. The evaluation stage occurs next as a manometer is connected to measure any leakage coming through or around the gasket. The leak rate is recorded at one minute, and again at fifteen minutes. The results are recoded and the average leak rate is calculated. The lower the average leak rate, the higher the gasket’s ability to seal. However there are many units used to measure Sealability (mL/min, cc/min or mL/hr) so you must make sure that you are comparing the correct test method and the reported units as well. Sealability is one of the most important characteristics in today’s sealing world, as even “small” leaks are frowned upon due to worker safety and environmental concerns.

Maximum Pressure

Maximum Pressure is used to determine a value where the material can be used safely (at room temperature). The material samples are pressurized until the gasket “blows” out and then using a FOS (Factor of Safety) a number can be determined, however it should be noted that in most cases, gasket materials are not used at room temperature. What we mean by this is that as gasket material is exposed to elevated temperatures the properties of the gasket change, so it is very important to check a PxT (Pressure x Temperature) chart for the material selected and your specific application (pressure, temperature, and media).

For instance, Durlon 9000 is rated for 1500psi, however as you can see in the below PxT chart at 400°F the maximum pressure would be 1000 psi. The Green area = safe to use; Yellow area = Do not use in these conditions or contact TFC applications engineering.

Durlon 9000 Pressure times Temperature chart

Final Thoughts

Hopefully this gives you a little more understanding and information on these four commonly misinterpreted and misunderstood gasket material tests, so that you can select a quality gasket material or at least be able to compare gasket materials on an “apples to apples” basis. If you are still unsure about gasket material selection, you can download our handy iGasket App, visit our website at www.trianglefluid.com or contact TFC application engineering (tech@trianglefluid.com). Chett Norton can also be reached via Twitter at @TFCgasketguru.



August 13, 2015

Triangle Fluid Controls Ltd.® Set to Release New Blog Covering Hot Industry Topics.

 

Triangle Fluid Controls Ltd. ®, the global Durlon® sealing solutions company, is set to launch their new blog September 2015 in order to provide a valuable resource for engineers, end-users and channel partners who may not have the specialized knowledge of a fluid sealing applications engineer.

“Providing excellent customer service for gasket users is tricky because we serve such a wide range of industries and end-users. We feel everyone should be able to find a reliable and accessible information source for their needs,” says Mike Shorts, Vice President and General Manager of Triangle Fluid Controls Ltd. ® “Not only will we be able to educate users on industry changes and standards, but by providing this resource we will be able to answer the questions we see as ‘hot topics’ on our customers’ and users’ minds. Some of these ‘hot topics’ just aren’t being addressed by others in the market, and that’s where we are prepared to step in.”

Some of the topics TFC plans on tackling are emissions, maintenance, leakage, safety, product lifecycles, and system failures in both gaskets and check valves. The new resource will be updated monthly by a team of contributors with extensive backgrounds in gasket and check valve application in order to help users determine their individual needs.

TFC is currently in the final stages of this new project after a very successful release of their new website late last year. Triangle Fluid Controls Ltd. ® has seen a flurry of web traffic and has noticed a need for this type of specialized technical information. Visit http://trianglefluid.com/category/gasket_blog/ for more details.

Established in 2007 in Belleville, Ontario, Canada, Triangle Fluid Controls Ltd. ® is globally known as the Durlon® sealing solutions company with innovative gasketing products for all major industrial sectors including oil and gas, petrochemical, mining, food and pharmaceuticals, and pulp and paper. Don’t miss a blog update by following Triangle Fluid Controls Ltd. on LinkedIn.
 

 



Triangle Fluid Controls Ltd.® is pleased to announce that they will be a supporting partner of SecureTrack™, a new program designed by Gasket Resources Inc (GRI®) that standardizes gasket materials, equipment, and installation procedures to eliminate bolted joint related non-accident releases (NARs) on railroad tank cars. Durlon® filled-PTFE sealing products, manufactured by TFC, are highly reliable, standardized gasket materials that are compatible with virtually any shipping commodity. TFC is excited to offer the SecureTrack™ technical support, training and customer service to our Canadian end-users.

Maureen Boyle, Rail Equipment Coordinator at Sunoco Inc. had this to say about the SecureTrack™ Program:

“Sunoco has over 3,000 tank cars in our fleet carrying various hazardous commodities. We were pleased to learn through testing by our laboratory that [the] Durlon® 9000 material is acceptable for use in all commodities we ship. Simplifying to one gasket material has helped Sunoco with compatibility, performance and standardization. We have confidence in the suitability and traceability of the branded Durlon® 9000 gasket material and have received excellent technical support, training and customer service.”

In coordination with GRI, TFC is proud to offer these improvements to railway safety in Canada. For more information on the SecureTrack™ program and to learn more about how Durlon® sealing products are compatible for your product shipments, please contact Triangle Fluid Controls Ltd.® at 1-866-537-1133, info@trianglefluid.com or by visiting www.SecureTrackProgram.com.

The Nozzle-Style BNC™ Check Valve Is Long Lasting and Low Maintenance

 

BNC

 

Exton, PA—DFT Inc., an industry leader in the manufacture of valves for more than 70 years, proudly announces the release of its new BNC™ Check Valve, a nozzle-style, axial-flow check valve specifically designed to excel in high-pressure applications.

Many natural gas companies and other power industries are now placing their pipelines below ground and are looking for a one-piece valve they can weld in and bury. The BNC™ Check Valve answers that demand with a precision nozzle-style valve that uses axial-flow technology to eliminate turbulence and prevent erosion and vibration. This design reduces downtime and maintenance costs and boosts capacity and accuracy.

Additionally, the BNC™ Check Valve provides a critical service to the power industry because the valve’s enhanced leak proofing under high pressure virtually eliminates acid and chemical leakage.

The BNC™ Check Valve is a spring-assisted, center-guided, non-slam check valve. It has an in-line globe-style body with butt weld ends, with the seat integral to the valve body.

The one-piece valve is designed for long life and low maintenance. Because it is welded into piping for service, the valve does not have any in-line maintenance capabilities.

The BNC™ Check Valve’s design meets API 6D and ASME B16.34, and its testing meets MSS SP-61 and API 598 (shell and seat). The valve is available in 10″ to 24″ line sizes, and it is constructed of A216-grade WCB carbon steel and other alloys per ASME 16.34 by request.

Trim materials are carbon steel and stainless steel with a hard-faced seat and disc. The valve can be installed either horizontally or vertically and is compatible with steam, water, and gaseous media. Custom sizing is available.

ABOUT DFT INC.

DFT Inc. manufactures severe service control valves and in-line check valves in its Exton, Pennsylvania, facility. DFT takes pride in working closely with end users to solve problems. The results are valves that provide superior performance, long service life, and low maintenance costs. Triangle Fluid Controls Ltd. is the Canadian channel partner for DFT. Our valves are available nationally through our qualified distribution network.

Durlong Sealing Products Logo

Triangle Fluid Controls Ltd. is excited to announce the release of our new DURLON® logo and tagline Durlon Sealing Solutions™. The new logo will become a global symbol of premium quality and superior performing sealing products continuing on the well-established Durlon® brand.

No matter where you are in the world, Durlon Sealing Solutions™ is your trusted partner for industrial sealing applications.

Sealing Devices in the
Environmental Goods Agreement

On April 9th, FSA President Mike Shorts met with senior trade officials from the Canadian Department of Foreign Affairs to discuss the sealing device market in Canada, and the positive and important role that these devices play in environmental protection efforts.

Unlike the USA and Europe, Canada has not fully supported the inclusion of sealing devices in the Environmental Goods Agreement which reduces or removes trade tariffs on environmental goods. Mr. Shorts traveled to Ottawa to educate the Foreign Affairs officials on the necessity of sealing devices so that they may be added to the program. The elimination or reduction of trade tariffs on sealing devices would allow access to better existing technologies at cost competitive prices and provide process industries with products that will exceed existing global emissions regulations.

“Reducing tariffs is a great step towards establishing market access to Canadian sealing device manufacturers and other FSA member companies,” he says.

“The sealing device manufacturing industry in Canada is relatively small compared to the USA, Europe and China but it has a long established history here and continues to be competitive in the global marketplace. Our company, Triangle Fluid Controls Ltd., through affiliated companies in its history, has been in the Canadian sealing products arena since 1922.”

 

Read Empowering Pumps blog here.