How to Choose the Best Sealing Materials Based on Chemistry & Strong Oxidizers

Strong oxidizers can damage metal, causing pitting or rust and treating possible safety concerns.

In chemistry, strong oxidizers are substances (like chromic acid) that can cause other substances (like seals and gaskets) to lose electrons. So, an oxidizer is a chemical species that undergoes a reaction that removes one or more electrons from another atom.

This causes a change in mass. Metals will turn into their respective heavier oxides, and the carbon in graphite will oxidize into carbon dioxide—which, although molecularly heavier, is a gas at room temperature.

This happens in pumps, valves, pipelines or any other equipment that have seals and gaskets carrying a strong oxidizer. It will cause pitting or rust and, depending on your choice of seal material, may require shorter service intervals. Ultimately, you may have to look for a more suitable material that can handle strong oxidizers.

More importantly, an oxidizing agent can cause or contribute to the combustion of another material.

The U.S. Department of Transportation defines oxidizing agents specifically. DOT’s Division 5.1(a)1 means that a material may enhance combustion or quickly raise pressure causing a rapid chemical reaction. A fire may start or, even worse, create or facilitate an explosion.

There have been instances of fires or explosions in mining, chemical process and even fertilizer factories where strong oxidizers were used.

Deadly Force

A West Texas fertilizer company storage and distribution facility caught fire on April 17, 2013. As firefighters attempted to extinguish the blaze, the plant exploded with the force of 10 tons of TNT, killing 15 people and injuring 200. It destroyed 60 nearby homes and left a 93-foot-wide crater where the plant once stood.

All said, it is important to choose the right sealing material for strong oxidizers. There are multiple products on the market for the chemical processing, oil and gas, mining and aerospace industries.

Gasket Selection - PTFE
PTFE (Polytetrafluoroethylene) Molecule

A fluoropolymer, such as polytetrafluoroethylene (PTFE), can handle most strong oxidizers, as long as the temperature is below 260 C (500 F). This is also true with a modified PTFE because they are chemically inert and stable.

Strong oxidizers will weaken most other material to various degrees. Much of a material’s capability to withstand a strong oxidizer depends on the used concentration, the service temperature and the service pressure. Therefore, consult with the sealing material manufacturer to ensure compatibility.

How Graphite Handles Strong Oxidizing Environments

Graphite starts as natural mineral flake and is mined in various parts of the world. The flakes form a layered structure of completely crystalline graphite, which is essentially elemental carbon. In this form, it is used for products like powdered lubricant and lead in pencils. It has excellent lubricity in this form.

Expanded graphite is produced with the use of strong oxidizing agents such as sulfuric and nitric acids. The acids weaken the bonds between the graphite layers, the flakes are then rinsed, dried and exposed to high heat.

The heat causes the layers to separate and expand dramatically to form expanded worm-like macro structures. The structures can then be recompressed into flexible graphite forms.

Graph Lock Flexible Graphite Garlock
Garlock’s Flexible Graphite, GRAPH LOCK

Flexible graphite is a soft material that is resistant to many strong chemicals and high heat. It has a low coefficient of friction and is proven to be advantageous over braided carbon or graphite fiber packings mainly as it is a better conductor of heat—a plus on moving shafts.

Flexible graphite is also naturally lubricious, conformable and resilient. It has good corrosion resistance and is compressible, allowing it to conform to most mating surfaces or valve cavities.

The chemical compatibility of flexible graphite can be enhanced with a blocking agent like PTFE. However, flexible graphite’s temperature limit will be restricted by PTFE’s limit of 260 C (500 F). If high temperature is an issue, this configuration will not work.

Flexible graphite, in combination with PTFE, is an extremely effective material in sealing fugitive emissions or volatile organic compounds (VOCs). VOCs have been targeted by several government agencies as a source of air pollution. Although, flexible graphite alone has a long way to go in stopping all fugitive emissions, it is a trusted sealing material for valves, flanges and stems in the chemical process, power generation, and oil and gas industries.

Flexible Graphite Pitfalls

Flexible graphite may be susceptible to chemical attack in the presence of strong oxidizing fluids, including air at extremely high temperatures. These include liquids such as 20 percent concentration of nitric acid or a 98 percent concentration sulfuric acid, the same chemicals that are used to break down mined graphite into expanded graphite flake.

Some flexible graphite compositions include oxidation inhibitors or are physically structured to extend temperature capability when exposed to these extra strong oxidizers.

The class of organic chemicals that should not be used are those that are highly oxidizing like nitrates, persulfates, perbenzoates and peroxides. Unacceptable compatibility for inorganic chemicals includes molten sodium, potassium hydroxide and chlorine dioxide.

However, many of the chemicals depend on the concentration, and some engineering groups can create an inhibitor that is right for a specific oxidizer. For instance, a 704 stainless steel cladding provides the user with protection against strong oxidizers while still providing the benefits of flexible graphite.

When in doubt, do a test loop using a pump to pressurize the strong oxidizer exposing it to flexible graphite. The pressure, temperature and concentration of the oxidizer must be exact as used in service, as to provide some idea of how the material will react to a given chemical.

It is easier to list the chemicals that are not compatible with flexible graphite (about 50) than those that are (more than 600 tested). A list of incompatible materials are listed below:

Strong Oxidizers for Flexible Graphite

  • Aqua Regia
  • Bromine (dry)
  • Calcium Chlorate
  • Calcium Hypochlorite
  • Calcium Nitrate
  • Chlorazotic Acid
  • Chlorine Dioxide
  • Chlorine Trifluoride
  • Chloric Acid
  • Chloroazotic Acid
  • Chloronitrous Acid
  • Chromates
  • Chromic Acid
  • Chromic Anhydride
  • Chromium
  • Chromium Trioxide
  • Dichloropropionic Acid
  • Dichromates
  • Hydrogen Dioxide
  • Hydrogen Peroxide
  • Lime Nitrate
  • Lime Saltpeter
  • Molten Alkaline
  • Nitrates
  • Nitric Acid
  • Nitric Oxide
  • Nitrocalcite
  • Nitrohydrochloric Acid
  • Nitromuriatic Acid
  • Norge Niter
  • Norwegian Saltpeter
  • Oleum (Fuming
  • Sulfuric Acid)
  • Oxygen (above +600 F)
  • Ozone
  • Perchloric Acid
  • Permanganate Solutions
  • Persulfates
  • Perbenzoates
  • Perborates
  • Peroxide Potassium
  • Bichromate
  • Potassium Chlorate
  • Potassium Chromate
  • Potassium Dichromate
  • Potassium Nitrate
  • Sodium Chlorite*(over 4%)
  • Sodium Hypochlorite
  • Sodium Peroxide
  • Sulfuric Acid
  • Sulfur Trioxide

For more information about which materials would be the best fit for your specific chemical application, contact Gallagher Fluid Seals today.

This original article was featured on the Pumps & Systems website and was written by Mark Freeman.

RoTechBooster Supplies Compressor Seals in the Power Plant

What is the RoTechBooster by EagleBurgmann?

RoTechBoosterThe RoTechBooster ensures abundant, reliable, and consistent seal gas flow, through fluctuating operating conditions; thus, clean and dry gas is supplied to the gas seal in every situation.

Features of the RoTechBooster

  • Electric driven centrifugal design
  • Hermetically sealed
  • Delivers seal gas flow as defined by API
  • 24,000 hours of operation before required maintenance
  • Various models available, depending on requirements

Advantages of the RoTechBooster

  • Simple to set-up, easy to operate
  • High reliability and availability
  • Unlimited continuous operation
  • Avoid seal failures
  • Low maintenance costs
  • Energy efficient
  • Eliminates the concern of unreliable external seal gas source


RoTechBooster Case Study: Clean Gas Despite Fluctuating Operating Conditions

The “Dock Sud“ combined power cycle plant in Buenos Aires, Argentina, is designed to adjust the power generation to the fluctuating electrical demand throughout all seasons. Managing the high demand during the summer months is particularly challenging, and the requirements for system component reliability are correspondingly high.

dock-sud-power-station

The power plant uses diesel engines and gas turbines to drive the generators. The diesel-driven generators run on a regular basis. The gas turbines are operated in start/stop mode so that they can respond quickly to high energy requirements or cope with peak loads.

As a low-pressure gas supply for the plant was only available to use for the gas turbines, a MAN Diesel & Turbo four-stage geared compressor with dry gas seals provided the means to increase gas pressure to the appropriate level for them. There is one geared compressor for each of the two gas turbines on site. Another geared compressor is used as back-up. Due to the nature of the operation, the turbines stop and start frequently placing the geared compressors in a pressurized stand-by mode when electrical demand drops. Continue reading RoTechBooster Supplies Compressor Seals in the Power Plant

Garlock Launches FLOOD-GARD Bearing Isolators for Fully Flooded Applications

FLOOD-GARD Offers Bearing Protection in Challenging Flooded Environments

Garlock has launched FLOOD-GARD Bearing Isolators for flooded applications. The patent-pending seal design provides bearing protection even in the most challenging flooded environments, extending the life of rotating equipment such as gearboxes, pumps, and motors.

“FLOOD-GARD™ allows Garlock to unlock value for our customers by taking industry leading bearing isolator technology, and advancing it even further, into a seal that excels in flooded conditions,” says Kevin Allison, Product Manager, KLOZURE®.

The latest addition to Garlock’s family of KLOZURE® Bearing Isolators, FLOOD-GARD™ is a revolutionary seal that combines improved safety and overall process efficiency with cost savings through extended equipment and bearing life. FLOOD-GARD’s Cam-Lock design provides excellent bore retention while allowing easy installation by hand, without the need for an arbor press. Other benefits include the ability to accommodate up to .015” of radial shaft misalignment and patented PTFE unitized construction that eliminates metal-to-metal contact, all while achieving an IP66 rating in most configurations — flanged, small cross section, step shaft and vertical.

FLOOD-GARD Benefits

  • Patented seal design provides bearing protection even in the most challenging flooded environments, extending the life of rotating equipment
  • Rugged, unitized construction for ease of installation
  • IP66 in most common design configurations
  • Available in standard and small cross section configurations
  • Substantially reduced installation time – NO ARBOR PRESS NEEDED
  • No metal-to-metal contact between stator and rotor
  • Handles up to .015″ of misalignment

FLOOD-GARD™ allows Garlock to unlock value for our customers by taking industry leading bearing isolator technology, and advancing it even further, into a seal that excels in flooded conditions.

FLOOD-GARD Design Parameters

  • Temperature: -22ºF (-30ºC) to 400ºF (204ºC)
  • Shaft to bore misalignment: ±0.015” (0.38 mm)
  • Axial motion to ±0.010” (0.25 mm)
  • Surface speed: to 3,000 FPM Max. (15.24 m/s)
  • Pressure: 7 psi intenal pressure

FLOOD-GARD Beta Sites

  • Gearboxes are common, but industries vary
  • Over 100,000 hours of runtime
  • Great success in all these industries

Beta Sites


For more information about Garlock products, or to learn more about the FLOOD-GARD, contact Gallagher Fluid Seals today.

Gallagher Fluid Seals is a preferred distributor of Garlock products and can help provide custom engineering solutions.

Why is Outgassing Critical in Optics and Electronics Applications?

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

Original content can be found on Parker’s Website and was written by Dorothy Kern, applications engineering manager, Parker O-Ring & Engineered Seals Division.


electronic boardFor some applications, a critical component of selecting a seal material is a phenomenon known as “outgassing”. However, even within the elastomer community, outgassing is not something that is commonly considered. Which begs the questions: what is outgassing and why is it important?

Outgassing is usually most relevant in vacuum applications, where the vacuum causes the elastomer to release constituent material. The constituent material could include water vapor, plasticizers, oils, byproducts of the cure reaction, or other additives used in the seal material. Outgassing becomes a problem if a thin film of those chemicals condenses and is deposited on nearby surfaces. Such a film poses major challenges in highly sensitive applications, such as optics or electronics, where cleanliness is of utmost importance. A seal material with low outgassing  is essential because it shows the seal material does not emit volatile constituents under vacuum conditions.

Weight loss of compounds in vacuum

Outgassing is most often characterized by weight loss of the seal material. The ASTM test method E595 is one way to quantify outgassing by measuring Total Mass Loss (TML %), Collected Volatile Condensable Materials (CVCM %) and a reported value for Water Vapor Regain (WVR %).  Measurements are taken following a 24 hour exposure to vacuum of 5×10-5 torr at a temperature of 257°F.

Taken together, these three parameters tell a complete story. The TML is reported as the percent of the specimen’s initial weight that is lost during the test; under standard criteria, the result must be less than 1.00% mass loss. Obviously, minimizing TML is a good thing, but it is not the only important factor. Collected volatile condensable material (CVCM) is the amount of outgassed matter from a specimen that condenses onto a collector during the maintained time and temperature. CVCM is of particular concern because any material that readily condenses in the test is likely to condense on and contaminate nearby surfaces during use. To pass the standard CVCM requirement, the amount collected relative to the initial mass of the specimen must be less than 0.10%. The final measurement, WVR, is the mass of the water vapor absorbed by the specimen after a 24-hour stabilization at 23°C in a 50% relative humidity atmosphere. There is seldom a pass/fail limit for WVR; instead this result is merely reported. In many applications, the small amount of water vapor lost by a seal may not be of concern, particularly if the application already includes a means of controlling moisture. Further, any WVR is presumed to be equal to the portion of original TML that was water vapor. The difference between TML and WVR is therefore presumed to be volatile organic material that has evaporated out of the material (only some of which condenses in the CVCM test), so minimizing the difference between TML and WVR is also of considerable importance.

To illustrate, we can look at the most recent outgassing data completed on a few popular low temperature fluorocarbon materials. Table 1 contains the results from a 3rd party laboratory to measure the outgassing properties of VM125-75 and VX065-75. Both had undetectable amounts of CVCM and very small differences between TML and WVR.  VX065-75 in particular displayed remarkably little outgassing as well as a low WVR.

There are a few additional resources detailing seal materials that are known for having low weight loss. The O-Ring Handbook ORD 5700, Table 3-19 (page 65 of the pdf), has a few legacy materials with weight loss percent after a two-week exposure to 1 x 10-6 torr vacuum level, at room temperature. Additionally, non-Parker resources such as the NASA website contain an interesting summary of a much broader range of materials.


For more information about outgassing or electronics applications, contact the Gallagher Fluid Seals engineering department.

The Future of Seals – Identifying and Communicating Levels of Wear

Seals do their jobs tirelessly, usually behind the scenes. Until now, machines mostly had to be dismantled to check the condition of these parts. That’s expected to change: At Freudenberg Sealing Technologies, a cross-disciplinary team is testing seals that identify and communicate their level of wear. They are based on a novel material that functions as a sensor.

It’s time for maintenance at a beverage bottling facility. Different components of the equipment are opened up, and the seals on tubes, pumps and valves are checked. If they are worn out, they have to be replaced. But if they are still intact, the check itself – a common yet expensive process – is superfluous. What would happen if the seals themselves could autonomously measure and transmit information about the level of their wear? And determine the exact point – no sooner and no later – when little of the seal lip is left and the seal has to be replaced? The future of seals may lie in self-identifying seals.

Seals Identifying Wear Automatically

A cross-disciplinary research team at Freudenberg Sealing Technologies addressed this question. Working with a customer from the process industry, experts developed a seal that measures its own wear. The key benefit: The maintenance of processing equipment – filling equipment in this case – could be performed based on actual need. Moreover, the service staff would have the opportunity to time the maintenance perfectly for the equipment’s operating schedule. Unplanned stoppages due to leaks would become a thing of the past.

Measurement Principle
The seal lip serves as an insulator. If it is worn, the capacity between the electrically conductive seal body and the housing changes.

Electrically Conductive Rubber

Seals are mostly made of elastomers that, in their pure form, are unable to process signals. To arm them with intelligence, it is possible to integrate a sensor or a microchip into a seal. But since the integrated element is a foreign body, it could impair the seal’s functioning. “So we focused our attention on approaches where the intelligence comes from the material itself,” Dr. Boris Traber, who is in charge of the development of new materials at Freudenberg Sealing Technologies. The researchers equipped a sealing material with special fillers to make the elastomer electrically conductive. At the same time, the material had to have qualities that are just as functional as those of a conventional seal. And, since the seals come into direct contact with the food during the filling process, they can only contain components that are on the positive list approved by the EU and the FDA.

Electric Signal Points to Leakage

The design and measurement principles that the seal uses to convey the level of its wear are just as important as its material mixture. In this particular application, an external transducer sends an electric signal over a lead to the seal. This creates voltage between the electrically conductive portion of the seal and the external housing, and the seal lip in-between insulates the two surfaces from one another. The greater the wear of the seal, the less it can effectively insulate the two electrodes from one another. As a result, the electrical capacity changes. If you measure the change, you can draw conclusions about the condition of the seal lip.

Development to Production Readiness

This smart seal is now due to be developed to production-readiness for specific applications. The effort involves material developers, product developers, process specialists and sensor experts who are working hand-in-hand with colleagues from operating areas, the Freudenberg Sealing Technologies sales organization and the customer’s application experts. Of course, it would take a good many experts to actually make seals that were talkative. But it would be possible – that much is clear, and the future of seals is looking bright.


For more information about sealing technologies, and to find out which seal might be a fit for you, contact Gallagher’s Engineering Department.

The original article was featured on Freudenberg’s website and can also be found in the May 2019 edition of their ESSENTIAL magazine.

Symptoms of Bad Valve Seals

Valve Seals Help Control Oil Consumption and Valve Lubrication

Valves are an important part of regulation in any system, and their seals are designed to be used in different types of engines for controlling oil consumption, and valve lubrication.The design and manufacturing of the seal is the key to ensure seal performance and longevity.

bad valve seals symptomsValves have many uses and are found in virtually every industrial process, including water & sewage processing, mining, power generation, processing of oil, gas & petroleum, food manufacturing, chemical & plastic manufacturing and many other fields.

Some examples of valve seals include: ball valve seats, globe valve discs, stem packing, stem seals, valve discs, valve packing, valve seals, and valve stem packing.

Having a proper valve seal can save you thousands of dollars in repairs at the end of the day, so it’s important to check them semi-regularly. For example purposes, we’ll focus on cars, but this can be translated across a variety of systems and industries. Here are some symptoms of a bad valve seal that may need to be replaced:

Performing the Cold Engine Test

One sure-fire way to tell if you have a faulty valve seal is to perform a cold engine test. When your vehicle has been sitting overnight or for a longer period of time, the top of the head of the valve cover will have some oil left over from the last time you drove. When you start the engine, the oil ends up getting sucked down through the bad seal into the combustion area, producing a blueish smoke out of the tailpipe. This may indicate that your valve is not securely sealed and that it’s time to get a new one.

Idling

Another way to test a bad valve seal is to be aware of what happens while your vehicle is idling. When your vehicle is stopped for a significant amount of time, high vacuum levels will cause the oil to build up around the valve system while it is closed. In a faulty valve seal situation, when you begin to accelerate again, this oil can end up getting sucked past the seal an into the valve guide. This causes more of this blueish smoke, due to the burning of oil, to come out the tailpipe.

High Levels of Oil Consumption

High levels of oil consumption is another indicator that you have a bad valve seal. This is because oil is being leaked out or burned excessively and causing oil to decrease at a higher rate than normal. You can detect this loss of oil with a basic oil dipstick and keeping a regular log of oil levels. If no oil leaks can be found around the vehicle, you may still have a bad valve seal, as the oil will likely be burned up causing excessive smoke.

High Levels of Smoke

Another indicator of a faulty valve seal, as mentioned above, is the high presence of smoke. It’s common for some exhaust smoke to be present when you first start your vehicle, but if it begins to last longer than normal, your valve seal may be deteriorating. In addition, if you have a bad valve seal, the excessive smoke will tend to come in waves as an indicator of oil burning.

Engine Braking Test

Engine braking is when other ways besides external braking are used to slow down your vehicle within an engine. When you have a bad valve seal, the oil that collects at the front cover of the head will end up burning when you push on the accelerator after coasting for a while. This is apparent especially when going downhill and again will be indicated by the excessive smoke that leaves the tailpipe. The oil here burns longer than in normal cases.

Acceleration Power is Compromised

The final indicator of a poor valve seal is a lack of acceleration power. You can also perform a compression test to see if this is the case. A higher level of compression will indicate that it’s a valve seal problem, while a low level of compression will indicate a piston ring problem. These two areas can be very similar in their faulty symptoms so it’s best to be informed on their differences.

A badly designed seal can result in engine oil flooding, which can eventually cause a breakdown. Gallagher Fluid Seals understands the importance of a well-designed industrial seal and can help design a custom solution for you, or supply you with standard off-the-shelf seals from the world’s top suppliers.


For more information about valve seals what why they fail, or to find solutions, contact Gallagher’s engineering department.

The original article can be found on Real Seals’ website.

A Short Guide for Rubber Seals & Design

Rubber seals are used in numerous industries to prevent the unwanted leakage of liquids and gases in various components such as pumps, valves, pipe fittings, and vacuum seals, to name only a few. However, all seals are not created equally. Rubber seal design consists of several elements to ensure that the seal delivers optimal performance in the given environment.

One of the most common types of industrial rubber seals, the O-ring, relies on mechanical compressive deformation to act as a barrier between mating surfaces, thus restricting the flow of fluid in predetermined areas. Several factors must, therefore, be taken into account in O-ring seal design to sustain the compressive force and maintain an effective seal.

Key Design Considerations

Rubber seals are available in a large number of material compositions, each with its own set of advantages and limitations. The selection of the appropriate material involves the consideration of specific factors including:

Dimensional Requirements

To provide a proper seal, the O-ring needs to be compressed between the mating surfaces. The deformation caused by this compression is what prevents fluid leakage. To achieve the proper compressive force and deformation, the cross section of the O-ring needs to be sufficiently larger than the gland depth.

As the two mating surfaces press together, the O-ring seal compresses axially and exerts an equal and opposite force at the top and bottom ends of the seal. If the O-ring is too small, the seal may not compress when the surface come together. On the other hand, an O-ring that is too large will over pack the gland and disrupt the connection between the mating surfaces.

Friction

Friction considerations are essential in dynamic applications – in situations that involve relative movement between the mating surfaces.

In reciprocating applications, these movements can generate frictional forces which may cause failure due to abrasion or extrusion and successive nibbling of the seal. In rotary applications, friction may generate excessive heat and seal expansion due to the Joule effect. In both of these applications, proper groove design, along with appropriate lubrication and speed of operation can help to avoid these issues. Silicone and related materials such as Fluorosilicone, liquid silicone rubber, and medical grade silicone are often avoided in dynamic applications due to their low abrasion/tear resistance.

temperature considerationTemperature

Long-term exposure to excessive heat can cause inappropriate rubber seals materials to deteriorate physically or chemically over time. Excessively high temperatures can cause specific materials to swell and harden, resulting in permanent deformation. Conversely, overly cold temperatures may cause material shrinkage and result in leakage due to loss of seal contact, or insufficient compressive force due to stiffening of the rubber compound.

Therefore, the appropriate seal material should be selected to withstand the expected temperature ranges of the environment. The length of exposure should also be considered. For example, would the temperatures be sustained in short intervals or at sustained levels?

Pressure

Differential pressures tend to push rubber seals (o-rings) to the low-pressure side of the gland causing it to distort against the gland wall. This action blocks the diametrical gap between the mating surfaces and results in the formation of a positive seal. Excessively high pressures can cause softer O-ring materials to extrude into the diametrical gap resulting in permanent seal failure and subsequent leakage. To avoid this situation, seal materials that operate optimally within the expected temperature range should be selected.

chemical compatibilityChemical Compatibility

One of the most critical considerations for rubber seals design and material selection is determining the material’s resistance to exposure to specific chemicals. Some fluids can react negatively with certain materials while having little to no effect on another. For example, Nitrile is highly resistant to petroleum-based oils and fuels, while the use of Butyl is avoided in applications with exposure to petroleum and other hydrocarbon-based solvents due to its poor resistance.

Remember to keep dimensional requirements, friction, temperature, pressure, and chemical compatibility in mind when it comes to customizing a rubber seal solution for your application.


For more information about custom seal designs or to see which seal might be the best fit for your application, contact Gallagher Fluid Seals.

The original article can be found on Precision Associates website, and was written in January 2019.

Compressor Seals: The Espey™ WKA250ND

Espey chamber seals have a modular design which means the seals can be composed using standard parts to meet individual application requirements. Espey chamber seals work with a very small operation gap between shaft and seal ring – leading to very low leakage – and are designed for dry-running and compensate radial and axial shaft deflections. Another advantage is that no sealing components which could generate additional shaft vibrations are actually fitted on the shaft. The seal rings are axially spring-loaded to prevent swinging up at pressure-less machine operation.

Espey chamber seals are applied in several turbo machines: integral gear, screw and chiller compressors, steam turbines, and shut-off valves for power plants. The main industries in which it is implemented are oil and gas, refining, chemical and petrochemical industry, power plants, and plants for iron and steel production. A further industry field with several references and successes is carbon dioxide capture and storage (CCS). So, what might a success story look like? Check out this WKA 802 HD mechanical seal for a multi-stage integral-gear compressor:

Espey Application Story

Espey™ WKA 802 HD as sealing for a multi-stage integral-gear compressor in a fertilizer production facility.

Client’s Issue

Urea is the worldwide leader in nitrogen fertilizer production. Urea is produced via high pressure synthesis from liquid ammonia and a gas-water mixture with 88.7 % carbon dioxide under high pressure and elevated temperatures in a synthesis tower. Thereby synthetic ammonia carbamate is produced, which is finally obtained as white granules under supply of acid and heat. The high pressure processes are generated by multi-stage radial integrally geared compressors. The seal has to work as leakage protection of the highly-compressed CO2.

The Espey Solution

turbo compressorEspey developed the compact chamber seal Espey™ WKA 802 HD with barrier gas and leakage port and up to 8 seal rings for this radial integrally geared compressor (which was designed by MAN Diesel & Turbo SE). The operation pressure of 140 bar (2031 PSI), the temperature of 225 °C (437 °F) and revolutions up to 40,000 min-1 were the main design parameters. Each of the 8 stages was equipped with an individual Espey ™ WKA 802 HD with different installation lengths, seal, and outer diameters. The one-piece seal rings with titanium bandage were designed axially spring-loaded to avoid vibrations during start and spin-out phase.

The Espey Result

The seal solution has been highly reliable and routinely operates maintenance-free, helping to maximize production.

About the Shaft Seal Espey™ WKA250ND – 1100HP

picture of WKA250NDFeatures
  • Chamber seal (modular design), optional with housing and lidVery small operation gap – low leakage
  • Dry running
  • Compensation of radial and axial shaft deflections
  • No sealing components mounted on the shaft and hence no additional shaft vibrations
  • Seal rings running contact-free – sliding faces and machine consume no additional power
  • One-piece seal ring with titanium bandage
  • Both side balanced seal ring inside chamber for short-term back pressure operation
  • Seal ring axially spring-loaded – no swinging up at pressure-less machine operation
Advantages
  • High reliability
  • Maintainability
  • Maintenance-free
Recommended Applications
  • Gases
  • Fumes and exhaust, solids containing, flammable
    (ATEX), acid containing and toxic gases
  • (Solids containing) steams/liquid mist
  • Oil mist/penetrating oil
  • Water
  • Oil and gas industry
  • Refining technology
  • Chemical and petrochemical industry
  • Pulp and paper industry
  • Metal production and processing
  • Power plant technology
  • Integral-gear compressors (one or multi-stage)
  • Screw and chiller compressors

For more information about mechanical seals, contact Gallagher Fluid Seals today. Gallagher is a preferred distributor for EagleBurgmann mechanical seals.

The original case study and materials for Espey WKA 802 HD can be found on EagleBurgmann’s website.

Maximizing Service Life: Recommendations for Storing Metal Hoses

When it comes to industrial products and applications, much of the discussion is focused on how to pair the right product and the right application. There are many different manufacturers of components that offer different features and benefits to suit the huge variety of factors that can affect plant components regardless of the industry. Vibration, corrosion, media consideration, service life, flow velocities, fluid dynamics…there are too many to list here! But what often gets ignored is how to handle and store those products before they ever get put into service.

picture of industryAfter personnel safety, avoiding unplanned downtime is the main priority for all industrial operations. Plants typically keep an inventory of maintenance items like hoses on hand to swap out as needed to minimize lost production time. Unfortunately, this inventory is not always stored or cared for properly. Some power plants keep replacement hoses, pumps, gaskets, and flanges on the ground outside. The end result of this kind of storage often defeats the purpose of having inventory parts because they can fail or lose significant service life before they’re ever even used. While these storage concepts apply to all maintenance components, let’s discuss metal hoses specifically.

External Considerations

The storing of hoses outside may come as a bit of a surprise (or may not) but it’s actually relatively common. Rain or dust seem like insignificant elements to stainless steel but they can actually facilitate a great deal of damage, especially over time. With rain, the phrase “evaporation equals concentration” helps to illustrate this point. Everything that is picked up by the rainwater on its way down (including nearby plant gasses) is delivered in a diluted state, but as the water slowly dries up, it leaves behind a concentrated residue that can cause corrosion (especially if the hose is in a position to collect water that can then pool on the interior).

Dust and particulate matter can do this too, especially inside the plant. Maintenance storage cribs and spare parts inventories can often be found near the equipment they’re meant to service. Heavy dust and particulate matter from process equipment can pick up other chemicals and off gases that are present in the plant, and carry them down onto the outside of uncovered hoses. This new mixture can cause unintentional chemical reactions that can corrode the exterior of the hose. Here is a specific example: In a coal-fired power plant – a baghouse collecting ash was improperly releasing a large amount of particulate…which then combined with lime dust and landed on nearby hose assemblies causing the exterior to become embrittled and fail. Even in cases where corrosion isn’t an issue, these fines can buildup on the outside of the hose in-between the corrugations and underneath the braid. This can be difficult or impossible to clean out, and can affect the hose corrugation’s ability to flex, or can become entrapped in the braid causing increased wear.

Hose Options for Storage

Fortunately, there are simple remedies for most of these issues. It’s always up to the end-user how they want to properly address their plant processes: be it either with a modification of the hose itself, or by rearranging how they store the hoses in the plant. Let’s break down each one separately: Continue reading Maximizing Service Life: Recommendations for Storing Metal Hoses

PTFE in Motorsports

PTFE and its many applications

Polytetrafluoroethylene (PTFE) has an interesting history and has been used in a number of ways over the years. There is, of course, the best-known PTFE brand Teflon® – the miracle cookware coating. But PTFE is also used in aerospace and computer wiring, and it’s even coated the fiberglass dome of the Hubert H. Humphrey Metrodome in Minneapolis. But the Metrodome isn’t the only sports-related application for PTFE. Because it’s so slippery and resistant to extreme temperature changes and chemical reactions, PTFE is an excellent component for many parts such as: bearings, gears, and of course, seals – like those used in so many motorsport vehicles. So, what role does PTFE play in the exciting world of motorsports?

PTFE in racing cars and trucks

TRITEC Seal’s PTFE rotary lip seals can be found in the race cars of nearly every NASCAR team, ensuring reliability for the chassis, drive train, and accessory drive systems. In addition to these high pressure seals, PTFE is now part of fuel hoses of many high performance vehicles. Relatively recent changes in fuel additives have shortened the life span of rubber fuel hoses, and PTFE, with its extreme temperature durability and chemical inertness, has been an ideal addition to fuel hoses.

picture of motorcycle ptfePTFE in motorcycles

Because of its ability to withstand high vibrations and temperature extremes, PTFE is an important component of a motorcycle’s piston seals. It can also be found in chain lubricant and some motorcycle oil.

PTFE in boats

High performance boats such as MasterCraft use PTFE seals to improve the output of their inboard shaft drive systems. PWC’s such as SeaDoo’s also take advantage of engineered sealing solutions by using PTFE rotary lip seals as well as wear sleeves in all of their PWC models. PTFE is often part of boat wax because of its ability to repel dirt and stains, and offer a high-sheen finish.

PTFE in riding mowers

Believe it or not, PTFE can even be found in the specialized sport of lawnmower racing. It is sometimes a part of the lubricant for belt pulleys. And PTFE rotary oil seals are used extensively in John Deere riding lawn motors to seal the crankshaft.

PTFE in go-karts

Go-kart racers may use a lubricant that includes PTFE, or it may also be part of the seal on a kart’s ceramic bearings, although there are a number of healthy debates about whether ceramic bearings make any significant difference in performance over standard bearings. (But that’s another story!).


For more information about PTFE and to see if it’s the right application for you, contact the Gallagher Fluid Seals engineering department.

This original article was originally featured on Tritec Performance Solution’s website.