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Case Study: A Single Mechanical Seal, But Twice As Safe Under High Pressure

Mechanical Seal SHVI and Plan 66A for Unmanned Pump Station of an Oil Pipeline

A well-known Canadian operator of an oil pipeline commissioned EagleBurgmann to develop a sealing solution for crude oil pumps. The requirement: It needed to be a single seal that was just as safe as a double seal with buffer pressure system. In addition, the sealing solution was not to be designed for only one pump type but should be installed in various pumps of one station.

SHVI Operating Conditions

The operating parameters were quite extensive: The seal needed to be suitable for a pressure range from 2.5 bar (36 PSI) to 99 bar (1,436 PSI) as well as for shaft diameters from 115 mm to 155 mm (4.53’’ to 6.10’’). Since the pump stations are operated unmanned, the seal must operate without an additional supply system. To protect the environment and personnel, however, the seal housing must not leak if the seal fails unexpectedly.

The solution: Mechanical seal SHVI from EagleBurgmann

These requirements were best met by the SHV series which has proven itself thousands of times over in crude oil pumps and MOL pumps (MOL: Main Oil Line) of all types worldwide for many years. For the Canadian customer, EagleBurgmann developed the SHVI sealing variant with loosely inserted seal face specifically for the high-pressure range. The seal face is single, but is twice as safe under high pressure and is designed such that it always builds a parallel sealing gap with the stationary seat. The deformation behavior of the seal  face was optimized for use in crude oil pumps so that the seal operates reliably even under very high pressures, sliding velocities and temperatures as well as pressure and temperature fluctuations.

Silicon CarbideEagleBurgmann selected a special quality of the silicon carbide material to be used in the pumps of the pipeline operator. This provides the seal face with particularly good emergency running properties and tolerance for partial dry running. In addition, the sliding faces have extremely precisely ground grooves which allow the seal face to be lifted quickly even in the low pressure range and contribute to stable operation in a wide pressure range.

Safety: Optimized API Plan 66A

Plan 66A, which has been available since introduction of API 682 4th Edition, was the obvious choice for the safety concept. Accordingly, the seal housing contains two throttles, and the seal chamber is connected to a pressure transmitter.

SHVI PipelineEagleBurgmann optimized the plan and uses a special inner, floating  throttle. This can withstand a product pressure of 99 bar (1,440 PSI) in an emergency. The pressure transmitter detects pressure changes in the seal chamber and signals an alarm if certain values are exceeded. At the same time, the seal leakage accumulated under low pressure is discharged to a central collection system in the pump station.

Test and Acceptance

The SHVI seal and the optimized Plan 66A were subjected to dynamic and static tests individually and together on EagleBurgmann test benches. The constant and reliable sealing performance in all operating states and the safe function of Plan 66A in the event of a fault provided impressive results. The required system safety was provided at all times.

The new concept of the SHVI single seal with optimized Plan 66A is economical, modular, reliable in operation, and offers the safety of a double seal.

There are plans to convert further pumps of the pipeline operator. The new concept of the SHVI single seal with optimized Plan 66A is economical, modular, reliable in operation and offers the safety of a double seal. For other customers as well, this type of seal has since proven itself in MOL pumps for several thousand operating hours.


To Learn More about the SHV series of mechanical seals, contact us today at 1-800-822-4063 or click the button below.

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Reduce Maintenance Costs When Sealing Dry Running Equipment

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

Original content can be found on Parker’s Website and was written by Nathan Wells, Application Engineer, Parker Engineered Polymer Systems Division.


My grandpa used to have a rusty, old air compressor in his shop. As a child, when my siblings and I would visit him, he’d use it to power air wrenches, grinders, and inflate flat soccer balls for us. I noticed it had a port labeled “ADD OIL DAILY” that was covered in the same thick layer of greasy dust as all the other unused junk in his shop. Knowing my grandpa, if asked about adding oil he probably would have said, “Oil is expensive. That’s how the companies get ya!” The compressor’s seals leaked so badly, you could hear the hissing even over the loud motor. I was certain one day it would explode.

picture of dry running equipmentPneumatic tools are common in factories, tool shops, and DIY garages around the world. Using compressed air for power is convenient, simple, and — when maintained properly — safe and efficient. However, air treatment costs can add up fast. Traditional rubber seals used in air tools require clean, low moisture, compressed air with the proper amount of lubrication added. Good Filter/Regulator/Lubricator systems (FRLs) cost as much as the tools themselves! So, what would happen if we didn’t have to provide pristine air?

Today we have the technology to create seals for tools which don’t require daily or even yearly upkeep. You’ll find these tools labeled “maintenance-free,” which sounds great to the guy responsible for maintenance. It sounds even better to the guy paying for maintenance … and to engineers designing tools who want to keep warranty costs down.

Seal materials for dry running

Early pressure seals were made out of leather. My grandpa’s compressor probably wasn’t that old, but even since his time, we’ve come a long way.

When I’m asked for seal recommendations in totally dry-running applications, my mind clicks to a material called PTFE (chemical name polytretrafluoroethylene). Most people know PTFE by the brand name Teflon® and are familiar with its use when applied to cookware as a high temperature, slippery, non-stick coating.

PTFE is a semi-hard plastic which feels slick to the touch thanks to its low friction properties. It’s considered self-lubricating because it leaves micro deposits on the sealing surface and reduces friction after just a few strokes. Because of this, it’s good for high-speed sealing and can operate completely dry.

By adding fillers to PTFE, seal manufacturers can tailor materials for greater suitability in meeting performance requirements for a wide range of conditions. String-like additives including fiberglass and carbon fiber increase pressure rating, wear resistance and seal life. Dry lubricant-type additives such as graphite or molybdenum disulfide (MoS2) further increase a seal’s ability to run without lubrication, and at higher speeds and pressures. In pneumatic medical, pharmaceutical, and food processing systems, clean grade mineral-based strengtheners may be used as additives.

PTFE seals for dry running equipment are available in several profile configurations:

Continue reading Reduce Maintenance Costs When Sealing Dry Running Equipment

What to Know, Avoid, and Consider When Planning Seals for Medical Devices

Seals are one of the most important components in many medical devices. While small in cost, seals for medical devices have a profound affect on the function of said device and the outcome of a medical procedure.

Engineered sealing solutions have advanced to meet the new medical device designs due both to new materials and to new processes for producing these seals. An understanding of the fundamentals of seal design, the tools available to assist in the manufacturing process and pitfalls to avoid will help in achieving a successful seal and medical device outcome.

Classifying the three basic seal designs

When approaching a new seal design, It is important to classify the seal based on its intended function. All seals fall into one of three distinct groups. While certain applications may combine more than one group, there is always one that is dominant. The three basic seal designs are:

Static — seal applications where there is no movement.
Reciprocating — seal applications where there is linear motion.
Rotary — seal applications where there is rotation.
Static seal applications are the most common and include those that prevent fluids and drugs from escaping into or out of a medical device. The seal design can range from basic O-rings to complex shapes. Static seals can be found in the broadest range of medical devices from pumps and blood separators to oxygen concentrators.

trocar design
New advances in trocar designs incorporating specialized seals allow multiple instruments to be inserted in the single trocar.

A reciprocating seal application with linear motion would include endoscopes that require trocar seals. These trocar seals are complex in design and allow the surgeon to insert and manipulate instruments to accomplish the medical procedure. These procedures range from relatively simple hernia repairs to the most difficult cardiac procedures. All of these minimally invasive surgeries employ endoscopes with seals that rely on seal stretch, durability and ability to retain shape during lengthy and arduous procedures. This particular seal application combines both reciprocating and rotary motion with the main function being linear motion.

A rotary seal application most commonly includes O-rings used to seal rotating shafts with the turning shaft passing through the inside dimension of the O-ring. Systems utilizing motors such as various types of scanning systems require rotary seals but there are many other non-motorized applications that also require rotary seals. The most important consideration in designing a rotary seal is the frictional heat buildup, with stretch, squeeze and application temperature limits also important.

Function of a particular seal design

What is the function of the seal? It is important to identify specifically if the design must seal a fluid and be impermeable to a particular fluid. Or will the seal transmit a fluid or gas, transmit energy, absorb energy and/or provide structural support of other components in device assembly. All of these factors and combinations need to be thoroughly examined and understood to arrive at successful seal design.

A seal’s operating environment

In what environment will a seal operate? Water, chemicals and solvents can cause shrinkage and deformation of a seal. It is important therefore to identify the short and long term effects of all environmental factors including oxygen, ozone, sunlight and alternating effects of wet/dry situations. Equally important are the effects of constant pressure or changing pressure cycle and dynamic stress causing potential seal deformation.

There are temperature limits in which a seal will function properly. Depending on the seal material and design, a rotary shaft seal generally would be limited to an operating temperature range between -30° F and +225°F. To further generalize, the ideal operating temperature for most seals is at room temperature.

Expected seal life – How long must the seal perform correctly?

Continue reading What to Know, Avoid, and Consider When Planning Seals for Medical Devices

Switching from PTFE to Kalrez® O-Rings Increase Life by 6,000%

The Seal Challenge

The filling line at Dow AgroSciences plant in Drusenheim, France – a global leader in pest management and biotechnology products – processes aggressive solvents, surfactants and concentrated herbicides at temperatures ranging from 10 to 45 °C, and pressures from 1.5 to 3.5 bars Eff. Filling machine valves on the line were fitted with dynamic PTFE O-rings, while the machine hoses were equipped with static O-rings, also of PTFE.

Each time the mechanical maintenance team performed a clean-in-place procedure at 80 °C, or made a product change on the filler, the PTFE seals became mechanically damaged. This meant they had to change the PTFE O-rings on a daily basis, since seal lifetime never extended beyond 24 hours before replacement.

In a different application at the same plant, seals of FEP/FKM, fitted to the piston rod of a Type SRC Alfa Laval valve, failed regularly after only 8 hours operation.

The cost to Dow AgroSciences in extra performance time and maintenance had become unacceptable, and the company sought a much more resilient sealing material that would better withstand frequent cleaning and product changes.

picture of kalrez as ptfe replacement

The Kalrez® Spectrum™ 6375 Solution

Dow Agro Sciences S.A. installed Kalrez 6375 perfluoroelastomer O-rings to replace the PTFE seals, with dramatic and immediate improvement.

They managed to extend the lifetime of dynamic and static seals fitted to their product filling line from one day to an average of two months, an improvement of some 6000%.

Also the seals of FEP/FKM, fitted to the piston rod of a Type SRC Alfa Laval valve, were replaced by Kalrez perfluoroelastomer parts. Operating lifetime has increased from 8 hours to between 8–12 months!

Kalrez 6375 parts are designed specifically for the chemical process industry. They provide outstanding performance in an extremely wide range of chemicals including acids, bases, amines and steam. The innovative patented curing system allows for continuous upper service temperatures of up to 275 °C in applications such as mechanical seals, valves, flanges and pumps where elastomeric sealing is critical.

In addition, Kalrez is a thermoset perfluoroelastomer part and offers excellent elastic properties and resistance to mechanical damage, unlike PTFE which is a thermoplastic and appears to lack the necessary resilience to withstand mechanical shock in a process application such as this.

Key Advantages of Kalrez 6375

Since switching to custom Kalrez 6375 O-rings Dow AgroSciences S.A. reports an average seal lifetime of two months. That’s an increase of approximately 6,000% over the previously fitted PTFE seals.

The operating lifetime of the seals fitted to the piston rod of a Type SRC Alfa Laval valve increased from 8 hours to between 8–12 months.

Switching to Kalrez® Spectrum™ 6375 parts allowed Dow AgroSciences to increase the operating uptime of their filling machines and to improve overall reliability of their packing line. They have also significantly reduced the time spent in O-ring replacement. The Mechanical Maintenance Manager also reported cost savings as a result of major improvements in safety and reliability, and in reduced maintenance.


Gallagher Fluid Seals is a preferred distributor of Dupont Kalrez® products. For more information or to speak with an engineer, visit Gallagher Fluid Seals or call 1-800-822-4063.

Your Seal Pump Just Failed and Production is at a Stop… Now What?

Can your Facility Afford Extra Downtime?

Introducing the new CartexExpress Rapid Ship Program!

CartexExpress

Fast delivery for Cartex mechanical seals is available (if necessary) when an order is received by 12pm CST.


Not familiar with Cartex by EagleBurgmann?

Cartex Mechanical Seals are engineered to provide the extra margin of performance.

EagleBurgmann’s mechanical seals are designed with greater attention to functional details like tighter tolerances for more accurate seal operation, greater axial movement to handle pump shaft movement, seal parts with robust cross sections for optimal seal stability in operation, and castings that meet ASTM A 351/351M standards for proven quality.

cartex mechanical sealHighlights and Advantages of Cartex

  • Ideal for use in ANSI process pumps
  • Universally applicable for packings conversions, retrofits or original equipment
  • Ideal seal for standardizations
  • No dimensional modification of the seal chamber necessary, small radial installation height
  • No damage to the shaft by dynamically loaded o-ring
  • Extended service life
  • Installation faults are avoided, cost-effective
  • No damage caused by dirt entered during assembly
  • Straight-forward and easy installation due to pre-assembled unit (reduced downtimes)

Recommended Applications

Cartex Seals are designed with greater attention to functional details like tighter tolerances for more accurate seal operation, greater axial movement to handle pump shaft movement, seal parts with robust cross sections for optimal seal stability in operation and castings that meet ASTM A 351/351M standards for proven quality.

  • Process, petrochemical, chemical, pharmaceutical, power plant, pulp and paper, water and waste water, mining, food and beverage, universally applicable, ANSI process pumps

Cartex Seal High-Performance Materials

cartex materials


So, Which Cartex Seals are Included in the Express Program?

  • Single seals
    • -ASTN and -ABTN
  • Dual seals
    • -ASDN and -ABDN

cartex express single and dual seals

Comparison With Competition: Part vs Part

Cartex seal faces, o-rings, drive pins and spring are more robust and
specifically engineered for superior strength, heat removal and maximum reliability and performance vs. competing modular seals.

  • Robust engineered design – Less sensitive
  • Fewer o-rings and components – Reduced possible leakage paths
  • High-performance pumping feature – Lower operating temperatures

cartex vs modular


So the next time your production is suddenly at a stop or you have unplanned issues and need a mechanical seal fast – contact Gallagher Fluid Seals and ask about the CartexExpress program.

Contact Gallagher

How Material and Spring Type Affect Friction Calculation

Dynamic Sealing Applications

This article will discuss how we understand and control friction in dynamic sealing applications.

It’s easy to stop a leak in a system by just welding it shut. But when you create a dynamic application, you generally have a limited amount of power to move the device you’re sealing.

Friction is a force that must be overcome in all moving pieces. Controlling friction allows us to make efficient equipment that can have a long wear life and move with a limited amount of force.

There are many factors that drive friction up or down in a dynamic application. Although this blog will focus on shaft seals, the same considerations apply to piston or face seals.

Below we’ll cover the following factors and how they affect the friction calculation in our seals:

  1. Shaft material, hardness, and finish.
  2. If the system will operate when lubricated or dry.
  3. The system pressure or vacuum.
  4. System operating temperature
  5. Seal material and the types of fillers.

canted flange with hardware

Seal Substrate

As a seal supplier, we usually like shaft materials to be hardened steel with surface finishes that are highly effective. Hardness above 50 Rc usually gives long wear life.

Having a good finish of 8 Ra. will insure long seal life and carry lubrication. However, depending on the application, there are times when a super finish of 2 or 3 Ra is justified.

Depending on shaft loading, there are many choices of surface finish that can reduce friction and improve the life of the seal. Understanding the bearing load under the seal helps to understand what finish is required to withstand the operating conditions.

There are some finishes that are detrimental to seal life. An example is a heavy chrome surface that looks sturdy, but usually can’t be ground smooth and is left with large peaks or valleys. Thin, dense chrome is often the opposite, giving good seal life if applied correctly. The engineers at Eclipse Engineering are prepared to make recommendations on hardness and finish. Continue reading How Material and Spring Type Affect Friction Calculation

Enhanced Surface Profiles for Gaskets

How this feature can improve performance and efficiency with gaskets

Gaskets have always been part of industrial production. However, gaskets have not always been forgiving, easy to use or simple to remove. What if the sealing products were designed to optimize the work put into them? What if the design had a level of intelligence built in? What if the design could make up for equipment damage? When used properly, enhanced surface profiles for gaskets can reduce leaks, spills and other releases that can damage the environment, put people at risk, result in fines and lead to costly downtime.

Using surface profiling to reduce area and increase stress is found in everyday life, from the soles of running shoes to the treads on vehicle tires. Reducing the contact area while maintaining compressive force results in increased stress. In the case of gaskets, traction or friction between a gasket and the flange faces is critical to holding internal pressure. If the downward force created by the fasteners in a flange is diluted or spread over a larger area, the overall stress is reduced.

Compressibility

Adding raised features to the surface of a gasket to reduce contact area and increase stress also tends to impact compressibility. Compressibility represents the ability of the gasket to conform to the surfaces it is being used to seal. Flange surfaces usually show signs of wear, pitting, scratches or other defects. It is cost-prohibitive to make two mating flange faces smooth and flat enough to seal without a gasket. The more compressible a gasket is, the better chance the user has of attaining an effective seal.

picture showing different gasket views
Image 1. (clockwise left to right) Traditional material sees heavier load around the gasket bolts and lighter load farther from the bolts. Image 2. Load distributed more evenly. Image 3. More stress toward the bolts. Image 4. Stress spread evenly around the gasket. (Images courtesy of Garlock)

Pressure Resistance

Compressibility also impacts the amount of pressure exposure on the gasket. When a flange assembly is pressurized, the internal media pushes outward on the inner diameter of the gasket. The thinner a gasket becomes, the less outward force it sees from internal pressure. This is referred to as improved “blowout resistance.” Unfortunately, one common error made when a gasket blows out is to replace it with a thicker gasket. This puts more gasket surface in the pipe or vessel for the internal pressure to act on.

Sealability

To create an effective seal, there are two functions the gasket must accomplish.

First, it needs to conform to the flange face to prevent the media from passing between itself and the flange faces. This is where the compressibility is important. Continue reading Enhanced Surface Profiles for Gaskets

Long Lead Times for Thordon? Try Vesconite – Available for delivery… NOW!

In 2018, Vesconite Bearings made a commitment to the U.S. market, increasing its readily available stock of Vesconite polymers and Vesconite Hilube in order to deliver quickly to customers.

Vesconite Bearings manufactures two main product types:

  • Vesconite is a specialised hard-wearing thermopolymer designed for challenging operating conditions, Vesconite gives up to 10 times the life of traditional bronze or nylon bushings. Combining internal lubrication, a low friction coefficient and low wear rates, Vesconite does not require external lubrication, even where conditions are dry and dirty.
  • Vesconite Hilube is a highly advanced thermopolymer in theVesconite Hilube Vesconite range, particularly suited to operating in wet conditions, including pump and marine applications. Combining low friction and low wear properties, Vesconite Hilube performs exceptionally well under high loads in difficult operating environments.

Their products can be found across a wide variety of industries, including agriculture, automotive, earthmoving, hydro, marine, mining, pumps, rail, and energy.

Whether customers need large bearings or small, stock is readily available and can be processed quickly … so you can minimize or eliminate downtime.

If you have ever experienced long lead times with Thordon, try Vesconite. Their products are consistent with quality, and they’ve had success across the globe in complex applications, including the U.S., Canada, UK, Africa, Norway, Argentina, Australia, and more.

Below are just a few quotes from satisfied customers:

VESCONITE HILUBE BUSHINGS SHOW NO SIGNS OF WEAR AFTER 7253 HOURS IN 3D PRINTER.
-Deon Eksteen

THIS PRODUCT WITHSTANDS THE MOST EXTREME CONDITIONS…
-Jonathan von Biljon

OUTLIVES ANY OF THE ALTERNATIVES AVAILABLE.
-Aleksandras Kaliberda

12 YEARS ON AND VESCONITE BEARING SHOWN MINIMAL WEAR.
-Martin Wibmer

Dr. Jean-Patrick Leger, Vesconite Bearings chairperson says Vesconite is dedicated to serving the U.S. market effectively. “We see the US market is as a high-growth-potential market,” says Leger.

 

With increased representation for Vesconite in the USA, its no wonder their high quality products are disrupting the market.


To learn more about Vesconite products, speak to a Gallagher representative today by calling 1-800-822-4063

BlackHawk Seals – The RBR Buffer Seal

The BlackHawk RBR Buffer Seal

The RBR Buffer Seal by Blackhawk Seals is a uni-directional rod seal designed to function as a buffer seal, protecting the primary rod seal from high pressure intensification and impulses. The RBR Buffer Seal provides the majority of the sealing function, while allowing a small amount of fluid bypass to assist in the pressure actuation of the primary rod seal. The use of the RBR Buffer Seal will greatly extend the life of the primary rod seal by protecting it from excessive pressure conditions. Pressurized fluid between the RBR Buffer Seal and the primary rod seal is allowed back into the cylinder via the slotted outside diameter rib, flexible outer sealing lip and side wall slots. This relieving function prevents excessive pressure build-up between the RBR Buffer Seal and the primary rod seal, which results in the premature failure of the primary rod seal due to excessive frictional heat build-up and seal extrusion. A high-performance Backup Ring is nested into the Buffer Seal inside diameter to prevent seal extrusion at high pressure and elevated temperatures. Both ID and OD sealing lips are knife trimmed to provide reliable sealing performance.

The RBR Buffer Seal is a dual element seal design made from a high grade of water resistant polyurethane material that can withstand the inherent strain of heavy duty mining and mobile cylinder applications. The Backup Ring provides superior extrusion resistance during high pressure operation and allows for increased extrusion gaps. When used in conjunction with a high performance primary rod seal, the RBR Buffer Seal provides extended service life and effective zero leakage sealing performance for medium and heavy-duty cylinder applications.

The RBR Buffer Seal can be utilized in a variety of demanding hydraulic cylinders requiring superior reliability and lasting performance, which is particularly suited for earth moving and other mobile equipment applications. The product range consists of industry standard sizes to accommodate imperial (inch) dimensioned housings.

So, what’s the RBR buffer seal material?

Continue reading BlackHawk Seals – The RBR Buffer Seal

Parker’s Low Temperature FFKM Provides Critical Oil & Gas Sealing Solutions

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

Original content can be found on Parker’s Website.


Oil & Gas Sealing Solutions with a Low Temperature FFKM

Technology advancements and new-to-world discoveries are constantly creating a new series of challenges for seal materials in the Oil and Gas industry. In today’s environments, seals are being pushed to perform in temperature, pressure and chemical extremes never before thought to be obtainable with rubber products. Application pressures exceeding 20,000 psi, service temperatures ranging from -40°F to upwards of 500°F, and exposure to some of the most aggressive media on the planet are placing immense amounts of stress on sealing elements. Parker’s FF400-80 compound has been formulated to provide a solution to all of these sealing challenges.

FF400-80 Compound – FFKM Product Features

  • Temperature range: -40° to 527°F
  • Best-in-Class low-temperature FFKM
  • Excellent compression set resistance
  • RGD resistant per ISO 23936-2 and TOTAL GS EP PVV 142
  • Sour service H2S resistant per ISO 23936-2
  • Maintained resilience at high pressures and low temperatures
  • Great for use in HTHP applications

Sounds great, but what’s the catch?

Continue reading Parker’s Low Temperature FFKM Provides Critical Oil & Gas Sealing Solutions