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How to Solve Large-Size Sealing Challenges at Temperatures up to 800°C (1472°F)

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Thorsten Kleinert, Business Unit Manager, Composite Sealing Systems Engineered Materials Group, Europe.


When classic sealing materials reach their limits, such as temperature ranges above 300°C and below -50°C – alternative materials are sometimes required, such as metal seals with appropriate coating/plating.

picture of metal sealParker offers metal seals made of stainless steel or nickel alloys in C-rings, E-rings, and other o-ring designs characterized by high pre-loading force and significant resilience. Drawing on many years of experience in the gas turbine market, Parker has continually expanded its expertise in large diameters and developed special problem solutions that substantially increase the efficiency of the machines.

Metal Seal Types and Sizes

The most important manufacturing technologies used to produce metal seals from stainless steel or nickel alloys are rolling, forming, CNC machining, welding, heat treatment, and coating/plating. In its more than 60-year history of producing metal seals, Parker has continually tackled the challenge of manufacturing increasingly large metal seals. Currently, spring-energized C-rings with a diameter of up to 7.6 m can be produced for which special forming machines and patented welding techniques were developed. They are supported by optimized special heat treatment and electroplating processes that make it possible to manufacture high-quality products even in such large dimensions. Additionally, Parker offers non-rotationally symmetric metal seals. These E-, O- and C-seals can be produced in lengths of up to 2.3 m on machines specifically developed for this purpose.

Products

  • C-seals: ≤ 3,000 mm (118 inches)
  • Spring-energized C-seals: ≤ 7,600 mm (299 inches)
  • O-rings: ≤ 1,200 mm (47 inches)
  • E-seals:
    • Heat-treated ≤ 2,700 mm (106 inches)
    • Segmented ≤ 7,600 mm (299 inches)

Materials and Coatings

picture of gas turbineThe base materials used are special nickel alloys that withstand temperatures of more than 800 °C. These cobalt-nickel-chromium-tungsten alloys or heat-treatable nickel super-alloys make high demands on the welding technology used and are reliably processed at Parker due to optimized manufacturing processes and comprehensive suitability tests.

The choice of plating is primarily focused on wear protection, corrosion resistance and improvement of the sealing properties. For this purpose, the surface properties of the metal seal are modified and a formable external surface layer with adjusted hardness is created.


For more information about  sealing large-size applications with high temperatures, contact Gallagher’s engineering department.

Gallagher is an authorized distributor for Parker products.

Case Study: Style 204 Expansion Joint w/ GUARDIAN® FEP Liner – Paper Mill

Garlock Style 204 Rubber Expansion Joint

picture of style 204The Style 204 family of spool-type expansion joints are manufactured with the industry standard narrow arch design. This style is intended to be used in dynamic conditions where both pressure and vacuum concerns are present.

Features and Benefits

  • Fully laboratory and field tested for long life and exceptional reliability
  • High pressure and vacuum resistance offer increased safety and ensure suitability for a wide range of applications
  • Single and multi-arch designs are available for a range of movement capabilities
  • Concentric and eccentric reducing configurations can be provided to join piping of unequal diameters
  • Available in a variety of elastomers and fabric combinations to meet the varied demands of temperature, pressure, and media

picture of paper mill

INDUSTRY

Pulp and Paper

CUSTOMER

Large South Eastern Paper Mill

BACKGROUND

A U.S. paper mill experienced multiple failures of expansion joints on the knotter screen pumps in the fiber area of the plant. The failures caused significant downtime and posed a safety hazard to employees working in the area.

OPERATING CONDITIONS

  • Size- 24”ID (DN600)
  • Temperature- Less than 250°F (120°C)
  • Application- Knotter screen feed pump
  • Media- Black liquor with wood fiber
  • Pressure- Less than 65 psi (4.5bar)

CHALLENGES FACED

A field survey determined that the expansion joints were experiencing significant elongation during installation. It was also evident that the pump and pipe flanges were not in parallel, creating angular misalignment. Additionally, the expansion joints were handling an aggressive media of black liquor and wood fibers, which collectively contributed to the failure.

SOLUTION AND BENEFITS

Through on-site troubleshooting and surveying of the expansion joints, engineers were able to recommend and design an adapter plate for the pump flanges to realign the pump to the piping. This allowed the plant to standardize the replacement expansion joints to Style 204 with GUARDIAN® FEP liner to be used in multiple locations. In addition, the mechanical bond of the GUARDIAN® FEP liner provided greater reliability than the adhesive bond of competitive PTFE lined expansion joints. Replacement cost and frequency has been significantly reduced as a result of this engineered solution.


The original case study can be found on Garlock’s website here.

Gallagher Fluid Seals is an authorized distributor of Garlock. For questions about products or to learn more about rubber expansion joints, contact our engineering department.

The Manufacturing Challenges of Tiny Spring Energized Seals

tiny spring energized sealEclipse Engineering has in-house capabilities to manufacture seals up to 55 inches in diameter, and over 100 inches through production partners.

While seals with huge diameters certainly grant their own significant levels of intricacy, here we’ll look at the other end of the spectrum: the micro-sized seals.

We won’t just look at a simple seal ring, but an inherently more complicated and geometrically detailed spring energized seal. As we’ll see, very small diameters make multiple manufacturing aspects more involved and challenging.

The Client’s Issue

A sealing solution in a customer’s epoxy dispensing equipment. They needed an effective seal for the reciprocating rod responsible for the flow-control and metering of the epoxy while being dispensed.

Operating Conditions:

  • Reciprocating Rod Seal
  • Epoxy Dispensing Head
  • Rod Diameter: 1.2mm [0.047”]
  • Stroke Length: 6mm [0.236”]
  • Cycle Rate: 15 per min
  • Media: Epoxy
  • Operating Pressure: 1,500 PSI
  • Temperature: 70° to 150°F

In general terms, most viscous media sealing solutions have three things in common:

  1. A variant of UHMW for the seal jacket,
  2. heavy spring loading, and
  3. multiple point contacts with increased interference.

In most cases, multiple nested V-Springs are incorporated to provide optimal load and energize the compound contact points on the seal. With this formula, we’ve had great success sealing media like epoxy, urethane, silicones and acrylics.

The heavy loading is necessary to effectively wipe the reciprocating rod. This is balanced with the correct material and design geometry to provide long wear life of the seal, which has the potential to be compromised under such loading.

The challenge in this case was to incorporate these same proven principles in a micro-sized seal.

The Eclipse Solution

Continue reading The Manufacturing Challenges of Tiny Spring Energized Seals

What Makes Kalrez® Different?

Oil and gas production and chemical manufacturing industries present sealing technologies with some of the harshest and most demanding operating environments.

Harsh and Demanding Operating Environments Require Chemically Resistant and Thermally Stable Seals

“We screen Kalrez against some of the most aggressive corrosive fluids,” says Dr Christopher Bish, Technical Fellow. “And in addition to the fluid testing, we did some compression set testing and stress relaxation testing at high temperatures. We now have one of the most chemically resistant and thermally stable compounds possible.”

We screen Kalrez against some of the most aggressive corrosive fluids

What really makes Kalrez sealing technology superior and more durable than competitors?

One of the things that sets Dupont Kalrez apart is their quality control system, which gives them the ability to track materials as they flow through the plant. Scanning the barcode on the part bag can pull up the entire production history of that part, including raw materials and process conditions.

Is Every Kalrez Seal Inspected?

Elastomer Seal: Perfluoroelastomer Parts

Dupont performs a 100% visual inspection. It’s one way to ensure the quality rate is high and the return rate is virtually non-existent.

Despite the foreseen images of clean rooms, manufacturing in the semiconductor industry can be a harsh environment and cost of o-ring and seal replacement is significant.

“Kalrez parts are used as sealing materials in semiconductor wafer processing equipment, where high temperatures, aggressive chemicals, and plasmas are used. The most important thing for Kalrez sealing prodcuts is that the materials are resisting those aggressive conditions and not degrading  or contaminating the chambers,” says  Dr. Shuhong Wang, Technical Fellow.

Chemical and Science That Makes Kalrez Better

The polymer chains are fully fluoronated, forming one of the most inert polymer structures possible. Other elastomers have weak points along the chain structure, which are vulnerable to chemical attack and thermal instability. This, in combination with the unique cross-link technologies, many of which are patented, provides optimum durability and protection.

Check out a tour of one of the Kalrez manufacturing plants and learn what makes it the best choice for your demanding applications.


The original video can be seen on the Dupont website.

For more information, or to find which compound is best for you, contact Gallagher Seals. We are an exclusive distributor of Kalrez® seals.

Incorrect Uses for a Rubber Expansion Joint

Pay careful attention to these possible rubber expansion joint issues

What’s wrong with this picture?

A rubber expansion joint is likely the least understood and most abused component in a piping system. They are flexible, stretchy, and easily forced into lots of places despite what the installation instructions say. Most of the time, rubber expansion joints are merely an afterthought in a multimillion-dollar piping systems – until things go awry.

The rubber expansion joint is unmatched for vibration isolation. If properly installed, a rubber joint can greatly reduce equipment nozzle loads. Its resilience allows it to be installed in many different systems under a range of temperatures, pressures, and media. What could possibly go wrong?

Blame Murphy’s Law if you want, the fates, or the alignment of planets. The reality of most failures is more straightforward. Most of the time, it is installation. More specifically, not following the manufacturer’s instructions. See Images 1 to 7 illustrating the ugly aftermath of ignored installation instructions and unforeseen operating conditions.

Learn these lessons well so your piping system does not become the subject of another article.

Respect the Dimensions

picture of joint being compressed
Image 2

Sometimes flexibility is a disadvantage. Why? Because it is easy to compress a joint into a space that is too small, which is exactly the problem in this example. The bead was damaged as the joint was forced into a gap between flanges, resulting in a seal failure. Spherical expansion joints rely on this bead to form a seal between flanges. If the bead is damaged, the building engineer will curse your name for eternity. Do not violate the face-to-face dimensions of an expansion joint.

Alignment is Still Necessary

picture of joint between misaligned flanges
Image 3

Pipes misaligned? Think a bendy, stretchy rubber expansion joint will fix the situation? Thank again. This joint was installed between two misaligned flanges. A typical scenario may look like this:

  1. Joint installed between two misaligned flanges
  2. Joint begins leaking at the flange-to-flang seal in a week (or month, or several months)
  3. Bolts tightened, leak stops. In the meantime, the rubber bead takes a compression set, becoming less resilient
  4. Repeat steps 2 and 3 several times
  5. Bead is compressed to about 1/16th inch, rips apart from the body, pump room is now  a water park

Do not turn your pump room into a water park  or, even worse, a sewage tank. Align those flanges before installing expansion joints.

Consider Steam Generation

picture of failed expansion joint
Image 4

Did you know water pumps can generate steam? This operator did not. In this unfortunate scenario (Image 4), the operator closed the pump isolation valves with the pump operating, dead-heading the pump. This situation is fine for a short duration, but eventually all that mechanical energy added to the water has to go somewhere. It went into heat. The water contained in the pump and pipe up to the isolation valves had so much energy added, that it flashed to steam. The expansion joint was the first component to fail, which was fortunate for the pump. The temperatures and pressures exceeded the rubber performance limits and the joint failed, nobly sacrificing itself for the greater good of the pump and piping. Continue reading Incorrect Uses for a Rubber Expansion Joint

Next Level PTFE Performance for Sanitary Applications

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.

picture of molded diaphragm
Molded Diaphragm made from calendared PTFE

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.

Continue reading Next Level PTFE Performance for Sanitary Applications

Sealing Solutions for Drinking Water and Service Water Systems

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Dr. Stefan Reichle, Market Unit Manager, Engineered Materials Group Europe.


picture of drinking waterWherever drinking water is obtained from any of its sources, pumped and processed, materials with low extraction levels and without any harmful ingredients are required. Sealing compounds for use in drinking water and heating applications are subject to diverse approval regulations. These regulations serve to assure the safety of water from the time of intake, via treatment, processing and transportation through to the consumer. Practically every country in the world has its own drinking water regulations specifying particular tests and including lists of approved ingredients. These regulations are complemented by physical and microbiological examinations.

The Parker Engineered Materials Group has developed a number of compounds, each of which meets a wide range of the required approvals, thus permitting the global utilization of sealing systems.

New universal compound combines excellent compression set and improved resistance against autoxidation

The peroxide-crosslinked plasticizer-free EPDM compound EJ820 was specifically developed for use in drinking water applications. The material conforms to all standard national and international drinking water approvals such as KTW, W270, W534, EN681-1 including the supplementary requirement, W534, NSF61, KIWA, WRAS, ACS. The material’s low compression set guarantees long life and thus permanent and reliable sealing of all fittings, valves and pipe systems. In addition, EJ820 exhibits enhanced resistance against autoxidation.

Parker materials cover a broad range of drinking and service water applications

  • Seals for solar thermal energy systems
  • Bathroom taps and shower heads
  • Press fittings
  • Heater valves and valve blocks
  • Drinking water applications
  • Heater pumps

Below are Parker material compounds and associated specifications:

picture of parker compounds

picture of regulations for drinking water


For more information about Parker products that are applicable for drinking water and service water systems, contact Gallagher’s engineering department.

Properly Measure Metal Hose Length: An Important Factor

There are several important factors to note when designing a metal hose assembly: alloy, fittings, media, pressure, and so on. One of the most crucial factors that is often taken for granted in industrial applications is hose length.  Utilizing the incorrect length in an assembly can be detrimental to its cycle life and potentially result in failure in an assembly.  If an assembly is too short, there is potential for the corrugation geometry to be deformed as the assembly is stretched between the connecting points.  Conversely, if an assembly is too long, it risks being over-bent as the hose tries to move out of its own way. To avoid these unnecessary failures, let’s review the steps to properly measure metal hose assemblies.

How to Measure Metal Hose Assemblies

picture of OAL and live lengthTo calculate the proper length of an assembly, it is first necessary to verify that the existing installation was properly designed.  Indication of improper design are factors such as torsion, over-bending, or compression of the assembly, which can lead to premature failure.

Next, you will need to measure the overall length of the assembly. The overall length is the total length of the assembly from end-to-end. When measuring for overall length, it is important to be aware that the points from which measurement should be taken vary between fitting types.  Measuring for overall length from an incorrect point on a fitting would result in an inaccurate measurement. How to measure various fitting types are as follows:

  • picture of measurements with various fittingsJIC/SAE Fittings: Measure from the seat of the fitting
  • Elbows: Measure to the center line of the fitting
  • Fixed Flanges: Measure to the face of the flange
  • Floating Flanges: Measure to the face of the stub end
  • Threaded Fittings: Measure to the end of the fitting

Finally, make sure that there is enough live length in the assembly to accommodate the required movements during service.  The live length is the portion of the assembly that is “active,” or has the ability to flex while in service. There are various formulas available to help calculate these length requirements. If it is determined that the existing live length is insufficient to accommodate the required movements, then Gallagher’s engineering team can provide expertise in appropriately adjusting the overall length of the design.

Utilizing these guidelines when measuring metal hose assemblies will help to ensure that an assembly is designed to sufficiently support the intended application.

Meeting the Tightest Tolerances

After proper measurement and design, it is important for a metal hose assembly to meet certain tolerance requirements as well. NAHAD sets guidelines for metal hose manufacturers in regards to the length tolerances to which a finished hose assembly must conform. Hose Master’s metal hoses are able to hold to those tolerances, as well as tighter specifications when the application requires. Adhering to strict tolerances in a completed assembly not only allows for solutions to the most stringent of applications, but also aids in providing maximum reliability, longevity, and safety.

For More Difficult Measurements

Taking measurements in the field can be difficult, especially if the installed assembly contains bends. For more difficult measurements, Gallagher can help.


The original article was written by Abby Svitana, Market Analyst at Hose Master.

For more information about measuring metal hose or for general inquiries about metal hose products, contact Gallagher Fluid Seals today.

The Danger of Complacency in Equipment Selection & Installation

Ensuring the correct materials are suitable for the application

When working with valves, flanges, and pumps, operators should never be complacent. The wrong gasket or packing in a deadly application could result in loss of life. Ensuring the correct materials are suitable for the application requires special attention because safety is critical. As Gordon DeLeys, compliance assistance specialist at the United States Occupational Safety and Health Administration (OSHA), said, “Safety should not be a company priority since priorities in an organization can and usually change. Safety and health need to be a core value of an organization. Safety is really a case of values versus priorities.”

picture of uss iwo jima
The USS Iwo Jima was an amphibious assault ship that experienced a catastrophic event in October 1990.

In October 1990, the USS Iwo Jima was heading into port for routine maintenance in Manama, Bahrain. The ship was the first to be designed and built from the keel up as an amphibious assault ship in Puget Sound Naval Shipyard, Bremerton, Washington, on Sept. 17, 1960.

Small packing leak can turn catastrophic

Valve 2MS-7 was a globe valve in the boiler room, and it needed to be repacked for a small packing leak and reconditioned while in port. The valve was worked on by an outside contractor who had limited understanding of military specifications and procedures.

The mechanic—who had 10 years of experience—decided to replace the fasteners on the bonnet because they were worn. Apparently, the mechanic asked one of the boiler room personnel for new nuts and bolts and was given permission to look through the boiler room’s spare parts bins. He selected four bolts, eight studs and 20 3/4-inch nuts. The mechanic had not noticed that some of the nuts were brass. Because those fasteners were covered with a manufacturer-applied black coating, they were mistaken for the correct grade 4 steel nuts. Closer examination and use of a scratch or magnetic test would have revealed their metal content, but instead the black brass nuts were installed.

The next day the valve was reinsulated with lagging. The foreman had not inspected the work done on 2MS-7.

The valve should have been reassembled using only B-16 steel studs—anything else was a violation of good engineering practice based on the service condition.

When the brass nuts were used on the studs holding down the bonnet of the valve, no one realized this was a critical mistake since the valve was going to be in service above 800 F and the temperature limit for brass is 400 F.

On Oct. 30, 1990, in preparation to get underway and proceed to her operating area, fires were lighted in the boilers of the vessel.

Shortly after, one side of 2MS-7 was initially pressurized with steam generated from Boiler No. 1. Three hours later, valve 2MS-7 was opened to supply steam to the generator that supplied electrical power to the vessel.

As steam at 600 pounds per square inch (psi) and 850 F began flowing through the valve, the brass nuts were expanding at a greater rate than the steel studs. The bolts started losing the strength to secure the bonnet to the valve body. After less than 30 minutes of operation, the valve failed catastrophically. Continue reading The Danger of Complacency in Equipment Selection & Installation

Freudenberg Develops Next-Generation Low Friction Bearing for Improved Lubrication

Freudenberg Sealing Technologies has developed an optimized design for its proven Levitorq axial thrust washers.

Through a new “scoop” feature, the enhanced Levitorq design is able to collect and push lubrication under the washer to enable higher critical speeds and enhanced performance. Levitorq is part of the company’s Low Emission Sealing Solutions (LESS) product portfolio.

The original Levitorq design was created to reduce weight, decrease friction, improve thickness/flatness control and often provide a cost benefit to the customer. It relies on the principles of hydrodynamic oil film technology and is designed to create a surface on which a bearing can roll, or a load can be applied. Traditionally, thrust washers are made from metals, but Freudenberg has used its material expertise and design knowledge, along with proprietary software and testing capabilities, to develop design alternatives in thermoplastic or thermoset materials that allow engineers to replace heavy metal thrust washers.

In pushing thrust washer technology further, Freudenberg engineers and material scientists looked at a variety of application parameters to optimize design performance, including thrust load, rotation speed, temperature, counter surface characteristics, lubricant type, and availability of the lubricant. A team of experts developed several scoop designs based on the types and availability of lubricants used in powertrain applications. These designs help optimize the availability of lubrication at the inner diameter, thus improving lubrication across the washer.

Nine Times the Pumping Ability, Three Times the Critical Speed

picture of levitorqPressurized or splash lubrication from the outer diameter is challenging to address because of limited fluid availability to remove heat. Recent design and material innovations from Freudenberg have enabled the use of polymeric thrust washers for such applications. The new Levitorq scoop feature significantly affects performance as it enables the application to use available fluid more effectively. Also, polymeric materials are designed to have low friction coefficients even in dry running conditions. These materials have dry friction coefficient one tenth of metal thrust washers.

Critical speed is when loss of pumping ability occurs due to centrifugal force. In a comparison between Freudenberg’s patent-pending D11 polymer thrust washer and its traditional thrust washer, the effectiveness of the new scoop design becomes obvious. The new polymeric thrust washers have nine times the pumping ability and three times the critical speed.

These designs are ideal for applications with limited or splash lubrication. The scoop feature is able to successfully move fluid under the washer to enable the application to run at higher critical speeds – up to 10,000 rpm – and pressures without failure.

An Exciting New Industrial Solution

“This patent-pending design is ideal for transmissions and driveline components, as well as a number of industrial applications,” says Ray L. Szparagowski, Technical Director Automotive and High Performance Plastics at Freudenberg-NOK Sealing Technologies.

“Our new Levitorq thrust bearings have the potential to optimize lubrication in most applications, so the possibilities are very broad and exciting.”

Freudenberg’s LESS portfolio of engine, transmission and E-Mobility products includes a variety of seals, gaskets, encoders, accumulators, sealing modules and lightweight housings. These products have been uniquely engineered to reduce friction and weight, cut fuel consumption, ease installation challenges and lower emissions. First developed and benchmarked for automotive applications, Freudenberg has been able to leverage its LESS technology for other industrial applications resulting in a significantly shortened development cycle.


The original article was featured on Fruedenberg’s website and can be found here.

Gallagher is an authorized distributor of Freudenberg products. For more information about this low friction bearing, LESS technology, or other Freudenberg products, contact our engineering department.