Custom Expansion Joints – Rubber

A flexible choice can adapt to permanent misalignment, preventing future damage.

Keeping aging facilities and equipment maintained is an ever-changing task that can jeopardize the goal of maximizing uptime. Years of thermal cycling, vibration or foundation settling can disorient piping or pumps. Piping engineers will use rubber expansion joints to account for these types of challenges in a rigid piping system. Permanent misalignment can set in after years of operation. The original-size expansion joint could no longer be the best fit when it comes time to replace.

Replacing a permanently misaligned expansion joint connection with the original part could lead to reduced service life and/or missed expectations of the new expansion joint. Determining the best way to accommodate this when it comes time to replace the existing expansion joint can have long-term effects on reliability. Since the original components may not fit in the newly disoriented flange connection, they are limited in their reliability.

Types of Customization & Benefits

Expansion joints are designed to withstand the pressure retention of rigid pipes, yet be flexible and absorb misalignment induced in these systems. However, there are limits to exactly how much flexibility can be absorbed before damage occurs. Using this flexibility to connect two misaligned pipe flanges will take away from how much movement can be absorbed during the actual operational period when the system is running.

Attempting to retrofit a standard-size expansion joint to connect a misaligned pipe connection can put excessive stress on the component and could lead to a shorter operational service life. For this reason, the Fluid Sealing Association (FSA) recommends no greater than ±1/8-inch misalignment of the pipe flanges during installation. Depending on the severity of misalignment, it can be advantageous to implement  custom expansion joints to minimize the stresses that cause these joints to fail or become damaged during installation.

Maintenance crews can also benefit by having a component that will fit precisely. Concerns for safety are present when attempting to put enormous pressure to compress, elongate or offset the joint so it will fit in place.

Face-to-Face Tailoring

Stress area stretched axially
Image 1. Stress area stretched axially during installation

Years of cycling, wear and other factors can contribute to the disorientation of a particular pipe connection. The length of an expansion joint, a dimension commonly referred to as face-to-face, bridges the gap between two parallel pipe flanges. A common industry problem is created when foundations settle and piping support structures transition lower than where it was originally constructed (Image 1). Expansion joints are designed to account for this, but choosing the correct replacement will make the difference between continued reliable service life or system failure.

Stretching an expansion joint to fit the changed flange connection often results in immediate damage that is only sometimes visual to the naked eye. A stress point on the outer cover of the expansion joint will usually become visible at the transition corner between the flat portion and the base of the arch in the form of a crack. The severity of cracking, elongation and settling will be aggravated when pressure in the pipeline is turned on.

Depending on nominal pipe size, industry standards will include standard face-to-face sizes of 6, 8, 10 or 12 inches, according to the FSA. When a standard 6-inch face-to-face joint is removed, the length between flanges could have been elongated to 7 inches or more. Many expansion joint consumers are not aware of the capability to build the expansion joint to the required nonstandard 7-inch face-to-face since it is not a standard offering. Building the replacement expansion joint to the nonstandard 7-inch face-to-face will eliminate any initial stress imposed on the joint.

picture of lateral expansion joint
Lateral offset expansion joint. and Angular offset expansion

Continue reading Custom Expansion Joints – Rubber

The Many Uses of Polytetrafluoroethylene Seals (Teflon)

Better known as Teflon in the industry, Polytetrafluoroethylene is widely used in practically every industry on and off the planet (and even beneath its surface!)

Medical Uses

white ptfe o-ring-teflonThis material’s primary claim to fame is its resistance to most chemicals. It inherently has an extremely low coefficient of friction, it’s easily machined from rods, tubes, or compression-molded shapes.

It’s one of the few polymers that are approved for medical implants due to its inertness to bodily fluids — the immune system principally ignores its presence in the body.

Moving away from the body, you’ll find PTFE or Teflon products in medical devices such as heart lung machines, rotary tools for cutting, and sealing devices for maintaining fluid streams for irrigation and pumping. Tiny fragments that may come loose during usage are not harmful to the body, and simply pass through the system.

Pharmaceutical Uses

In the pharmaceutical industry, Teflon is used in the processing of drugs for equipment used to manufacture such as mixers, presses, and bushings. Teflon is found in a variety of applications, as any debris from the seal will pass through the body without consequence.

When considering press machinery (which are often water driven to ensure any leakage will not spoil the product), Teflon seals are often used to help reduce friction — especially in repetitive presses where a build-up of heat would be detrimental to the seal and the product.

Food & Beverage Uses

Mixers are another area to ensure keeping grease and other contaminants from the motor to not descend into the product from the mixer shaft.

Another area is pressure vessels where two shells are clamped together to ensure product remains sealed inside. Failure of these seals usually results in loss of product.

Non-metal bearings that don’t requiring grease in rotary motion are an excellent place for Teflon style bushings. These bushings provide long life with very low friction while not contaminating the product. Shaft wear from the bushing may be eliminated with the use of Teflon.

Types of PTFE (Teflon) Seals

Seals in the medical field can be as simple as a static O-Ring, or a mechanical face seal which is costly and requires special consideration during installation. Most dynamic applications can be resolved with spring-energized style seals, which often have very low friction and can be clean in place (CIP) if required.

There are different styles of springs, such as cantilever or canted coil that provide varying loads. The cantilever-style spring-energized seal provides a linear load based on deflection providing a high level of seal-ability. It can be silicone-filled to provide CIP for ease of washing, and there are a variety of materials that are FDA compliant and that work well in both viscous and pure aqueous fluids.

Canted coil spring-energized seals provide a unique feature of controlling the load the spring exhibits on the sealing element. This allows for control of a device being manipulated during a procedure.

The polymer properties give the user materials with the lowest possible friction, while still sealing in an application. The load from a canted coil spring allows the user to feel a tool in a catheter while passing the catheter through a tube, and still retaining a seal.

As you can see, PTFE has a variety of uses across a broad range of industries. GFS’ partner, Eclipse Engineering, manufactures PTFE and can help provide solutions to customers facing both simple fixes or complex problems.

Contact us today to see if PTFE might be the right choice for your application.


For custom engineered parts, or for more information about a variety of PTFE seals we can provide, contact Gallagher Fluid Seals today.

The original article was written by Eclipse Engineering and can be found on their website.

What does a good seal engineering drawing look like?

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

Original content can be found on Parker’s Website and was written by Fred Fisher, technical sales engineer of the Engineered Materials Group.


seal drawingYou just spent 6 months testing, stretching, aging and exposing your new seal design to 12 different chemicals. Finally, you are done. So what does a good technical drawing for a seal include? For most companies, the drawing is simple. For an O-ring, we draw a generic circle and show an ID and width with some sort of material call out.

But now fast forward 20 years. Someone consults the drawing – how do they know the criteria you used to select the seal specified?

Just last week I asked my customer, who was having seal failure, about the issues on their engine sensor: “Was the original seal specified to be compatible with biodiesel?” The engineer consulted their drawing, but besides the generic circle, it lacked any background on what material compatibility was considered when the seal material was selected. The ASTM description on the drawing did not include a reference to or indicate compatibility with biodiesel.

Be specific with materials

Over time, the operating parameters of a system or product can change, so it is important to know what parameters were used for the original seal selection. The goal of the drawing is to assure that the engineers and procurement team understand what performance is required from the seal and why the specific elastomer was chosen.

So how do you make your drawing more valuable to your company?

  1. Define and list on your drawing all the operating conditions you anticipate the seal will see, such as temperature, pressure, and any other application specific operating conditions.
  2. Prepare a list of fluids as well as the concentrations of each fluid that your seal will be exposed to. Add these on your drawing. In addition, make sure you consider fluids that could come into contact with the seal indirectly through failure of other systems that are part of the product or even by cleaning the product.
  3. List the selected compound and manufacturer on the drawing. Clearly define what testing the compound was put through or what testing is required for approval.
  4. If you select a compound that was resistant to compression set, high temperatures or low temperatures, as well as explosive decompression, this should be clearly stated on the drawing.
  5. List clearly the industry standards the seal is required to meet, such as UL, FDA or NSF.

List fluid compatibility requirements

fluid compatabilityTime and time again, I see seal quality and performance failures when a new supplier is selected and the real requirements for the seal were either forgotten or not clearly defined. Clearly defining these parameters and making them transparent will allow your purchasing and technical team to understand, select, and evaluate the correct compound that meets your products sealing requirements.

Once you select a compound for your specific application, it is important to test and validate that the compound chosen is compatible with the fluids you are using. Parker can typically supply small compound samples for soak testing in the fluids your seal is exposed to. If you choose to list an alternate compound on your drawing, that compound must also be tested and validated for compatibility.

Remember when developing drawings standards, assure yourself that if someone consults a drawing that is 2 years old, 5 years old or even 20 years old, they will know the intent of the original seal design.


For more information about custom sealing solutions or information about Parker seals, please contact Gallagher’s engineering department.

A New Generation of Conductive Seals

Freudenberg Sealing Technologies is developing a new generation of conductive seals designed to ensure a durable electrical connection between housings and shafts while preventing bearing damage caused by electricity and electromagnetic radiation.

In many operating conditions, the shafts used in electric powertrains are electrically insulated from their housings. The insulation is created by the lubricating films in the contact zones for the bearing and the shaft seals. Lubrication is necessary to promote long-term system functionality. Alternating current and its electromagnetic fields produce changes in the electric potential between the rotor and the stator and the rotor becomes charged. The current can only be drained off through a grounded system that allows the electricity to travel from the shaft to the housing. If there is no grounded pathway, the current flows to the area of least resistance – the bearing – and produces an abrupt discharge when electricity flows from the inner ring to the outer ring across the bearing. Discharge flashes cause surface burns and material compromises that permanently damage the system. The result: The contact surfaces in the rolling bearing are steadily and systematically destroyed. The mounting becomes noisy and the bearing must be replaced to prevent powertrain failure.

Finding the conducting element

conductive simmeringDamage from electric current must absolutely be avoided. The simple solution is to develop a lasting, reliable electrical contact between the shaft and the housing that facilitates a continuous flow of electricity and prevents excessive build up and sudden discharges. The more difficult challenge is to find a system element that can conduct the current via ongoing contact with both the housing and the shaft. As a rule, seals are made of insulating materials and are not suited for this purpose.

For several years, Freudenberg Sealing Technologies has been producing an electrically-conductive nonwoven disk as a series- production system element. The advantage: It is firmly connected to the shaft seal ring and requires almost no additional installation space. The conductivity of the nonwoven is achieved with special fibers that are embedded in a matrix. The system has been used in regular-production electric vehicles for years and reliably prevents bearing damage. The electric resistance in this approach is already at a very low level, but the sealing specialists at Freudenberg continue to develop the solution further.

Power densities continue to grow in upcoming electric powertrains, increasing current, voltage and disruptive electromagnetic fields. To offer a robust solution for these situations, the company is now developing a new generation of conductive seals. The first validated, functional models in this category will be available within a few months. “Our goal is to achieve constant resistance values over a long period of operation – even in adverse conditions,” said Dr. Tim Leichner, who is responsible for Strategic Product Advance Development at Freudenberg.

A new dynamic testing procedure

To fulfill the new requirements for seals in electric powertrains, Freudenberg Sealing Technologies has developed the appropriate test procedure to evaluate and compare the functioning of current dissipation elements. Test stand trials have shown that static measurements of the elements’ electrical resistance are not adequate to predict electrical conductivity during actual dynamic use. So development engineers in Germany developed a dynamic testing procedure that delivers alternating-current flows in the frequencies found in automobiles.

“There is the possibility of doing even more with conductive seals,” said Francois Colineau, who is in charge of the development of this product line at Freudenberg Sealing Technologies. “High electrical conductivity lends itself to possible shielding of disruptive electromagnetic radiation.” The exit point of the shaft from the housing, in particular, is normally a location where “impermeability” is only achieved with difficulty. At this location on every electric motor, there is a shaft seal that could help handle the shielding. It would be possible to combine the sealing of oil and other media with impermeability to electromagnetic radiation – without necessarily adding another nonwoven layer. “Perhaps we will even find an entirely new electrically conductive sealing material. We’re working on it,” Colineau said.


The original article can be found on Freudenberg’s website.

For more information about this new generation of conductive seals, contact Gallagher’s engineering department.

Heisman Winner… and Rubber Salesman?

Jay Berwanger, Heisman Winner.

To football aficionados, Jay Berwanger is well-known as the winner of the first Heisman Trophy and the first player chosen during the National Football League’s first draft. Less well-known is that he achieved his athletic successes at the University of Chicago, a school now more closely associated with Nobel prizes than big-time football. Berwanger, a halfback, played for the University of Chicago Maroons at a time when Chicago was a member of the Big Ten Conference–before Robert Hutchins, the University’s president, famously abolished varsity football in 1939.

Even in an era before football teams were divided up into offensive and defensive squads, Berwanger was renowned for his versatility.

Berwanger PosingIn 23 varsity games in three seasons with the Maroons, he scored 22 touchdowns and kicked 20 extra points. He gained 1,839 yards on 439 rushes for a 4.2 average. As a sophomore, he played 60 minutes of every Big Ten conference game and was voted the team’s MVP. During his collegiate career he returned 54 kickoffs and punts for a 31.8-yard average, completed 50 of 146 passes for 921 yards and caught 12 passes himself for 189 yards. He averaged 38 yards on 233 punts and 46.3 yards on 34 kickoffs. He once recorded 14 tackles playing linebacker in one half.

In 1935, the Chicago Tribune awarded Berwanger the Silver Football for Most Valuable Player in the Big Ten. His coach, Clark Shaughnessy, called him “every football coach’s dream player. You can say anything superlative about him, and I’ll double it.” Of the 107 opposing team players he faced during his senior year, 104 said the six-foot, 195-pound Berwanger was the best halfback they had ever seen.

In November of 1935, Berwanger received a telegram from Manhattan’s Downtown Athletic Club, informing him that he had won a trophy for being the “most valuable football player east of the Mississippi,” as well as a trip for two to New York. “It wasn’t really a big deal when I got it,” Berwanger recalled in 1985. “No one at school said anything to me about winning it other than a few congratulations. I was more excited about the trip than the trophy because it was my first flight.” The prize was later renamed the John W. Heisman Memorial Trophy, after the club’s athletic director, the following year.

He was born John Jay Berwanger in 1914 in Dubuque, Iowa. In high school, he excelled at wrestling and track as well as football, winning renown as an all-state halfback. After graduation, Iowa, Michigan, Minnesota, and Purdue all tried to recruit him, but he opted for Chicago, which had offered only a basic tuition scholarship of $300 a year. To meet his expenses, Berwanger waited tables, cleaned the gymnasium, fixed leaky toilets, and operated elevators. “Times were tough then,” he said. “I wanted to attend a school that would give me a first-rate education in business, without special treatment, so that I would be prepared when opportunities were certain to return.”

During his freshman year, Berwanger was coached by the legendary Amos Alonzo Stagg, who helped define the game of football as we see it today. Berwanger’s first year at Chicago was Stagg’s last. As well as captain of the football team, Berwanger was captain of the track team, senior class president, and head of his fraternity, Psi Upsilon.

Berwanger was the only Heisman recipient who was ever tackled by a future president of the United States–Gerald Ford, during a 1934 game between Chicago and Michigan. “When I tackled Jay in the second quarter, I ended up with a bloody cut and I still have the scar to prove it,” President Ford recalled. “Jay was most deserving of his Heisman Trophy. He could do it all. He was an outstanding runner as well a passer, he could kick, punt, and make field goals–and in those days the ball was round so it was much harder to throw. He and I had met several times in the years since that game and I remember him fondly as one of the greatest athletes I’ve known.”

Berwanger was also the first player chosen for the National Football League during its first-ever draft in 1936. After the Philadelphia Eagles signed him, Coach George Halas of the Chicago Bears acquired the signing rights. But when Berwanger asked for $25,000 over two years, Halas decided that was too much money, so Berwanger took a job as a foam-rubber salesman.

Jay Berwanger, Rubber Salesman and Lieutenant Commander

Shortly after starting his job as a rubber salesman, Berwanger enrolled in the Navy’s flight training program and became a Naval officer during World War II. He eventually earned the rank of lieutenant commander.

After the war, Jay Berwanger founded Jay Berwanger, Inc., a manufacturers’ sales agency specializing in rubber, plastic, urethane and other elastomeric materials for car doors, trunks, and farm machinery. His company established a guiding philosophy to create superior value for all customers and principals through dedicated service and by providing integrated solutions to customers’ applications.  Jay sold his company in the early 1990’s when its annual revenue was $30 million.

Post-Heisman and Rubber

Berwanger Heisman and FootballBerwanger was never sure what to do with his Heisman Trophy, which was too wide for a mantelpiece and too large for a coffee table. For years, his Aunt Gussie used it as a doorstop. Berwanger eventually gave the trophy to the University of Chicago where it is on display.

In 1954, Berwanger was inducted into the College Football Hall of Fame. In 1989, he was included on Sports Illustrated’s 25-year anniversary All-America team, which honored players whose accomplishments extended beyond the football field.

Berwanger died in the summer of 2002 and is survived by three children, three step-children, 20 grandchildren, and 13 great-grandchildren.


Information for this article was gathered from Sports Illustrated’s vault, the University of Chicago, and New York Times.

Gallagher has no relationship or partnership with Jay Berwanger Inc. If you liked this article or have an idea about another topic, please let us know!

The Proper Use of Lubrication and its Success with Bolted Flange Connections

Extra energy transmitted can produce larger sealing stress on the gasket.

The bolt as a screw is one of the six simple machines. A simple machine magnifies or changes the direction of an input force. By means of mechanical advantage, a bolt can dramatically increase its input force. Take for example an 8-bolt flange with 3/4-inch diameter bolts. By manual effort alone, a person can easily develop a total bolt load of over 110 tons. This article explains the mechanics by which the mechanical advantage is possible and then draws attention to how friction can deteriorate the end effect of a bolt’s mechanical advantage.

The means by which a bolt can greatly magnify input load is by leverage. One source of this leverage is afforded by the geometry of the bolt. The other is the leverage from a tightening tool—in this example, a torque wrench. To illustrate the mechanics of a screw thread, consider a 3/4-inch diameter, Unified Course (UNC), A193 B7 bolt with a yield strength of 105,000 pounds per square inch (Image 2 identifies the geometrical characteristics of a bolt that create leverage).

The pitch circle is defined as the circle that passes through the pitch line of the threads. The pitch line is the theoretical point of contact between the male and female threads.

Threads of a bolt
Image 1. The threads of a bolt essentially form an inclined plane

The pitch is the distance between thread crests, and is the axial distance the bolt travels in a single 360-degree turn. The threads of a bolt essentially form an inclined plane wrapped around the minor diameter of the bolt (Image 1).

The horizontal distance (pitch circle) traveled divided by the vertical distance traveled (pitch) is the mechanical advantage of the bolt geometry.

For the 3/4-inch bolt, the values for the pitch (P), pitch circle diameter (Pd) and pitch circle circumference (Pcc) take on the following values: 0.10 inch, 0.6850 inch and 2.152 inch, respectively. The helix angle becomes Tan-1 (P/Pcc) = 0.266 degrees.

Image 2. Geometrical characteristics of a bolt that creates leverage

The pure mechanical advantage of the threads, designated as MAt, is the horizontal distance traveled divided by the vertical distance traveled, in Image 2. Its value becomes MAt = 2.152 inch/0.10 inch = 21.52:1. Relative to the pitch circle, 1 pound of input force would create almost 22 pounds of output force.

Now evaluate the additional mechanical advantage of a torque wrench. Presume the use of a 3/4-inch drive, 48-inch-long torque wrench with an effective length (based on the pull-point of a person’s hand) of 44 inches. The mechanical advantage of the wrench is its effective length (Le) divided by radius of the pitch circle.

Now calculate the pure mechanical advantage of the wrench (MAw) as Mw= Le/(Pd/2) = 44 inches/(0.6850/2) = 128:1. A single pound of input force on the torque wrench results in 128 pounds of output force.

To get the total pure mechanical advantage of this system, combine MAt and MAw. This is done by taking the product of the two values.

The total pure mechanical advantage (Mtot) of the two effects then becomes Mtot = Mt x Mw = 21.5 x 128 = 2,752:1. If the mechanical advantage actually attained this value, 15 pounds of input force would yield the bolt.

Obviously, it does not. The reason is, pure mechanical advantage of a system can never be attained. There are always (energy) losses.

In the instance of a bolt being torque tightened, those losses can be extraordinarily high. The most important energy loss is friction. To better understand how dramatically friction can negatively impact a bolt’s clamping force, evaluate its affect using a common, long-form version of the torque equation. Tlbf is the calculated torque to attain a bolt load, FB.

The first term in Equation 1 is the useful input energy that goes to stretching the bolt. The second and third terms account for the energy being lost to friction.


T = [(pt/2 π) + (utdt/2 cos(a)) + (un dn/2)] FB/12
Where:
pt = pitch of the bolt thread = 0.10 inch
dt = mean contact diameter of thread = 0.685 inch
dn = mean contact diameter on nut spot face = 0.8738 inch
a = half thread angle = 30 degrees
ut = friction coefficient on threads = 0.13
un = friction coefficient on bearing surface (spot face) = 0.08
FB = value of (single) bolt load = 17,561 lbf.
T = torque, in. lbf.
Equation 1


Specifically, the second term is the energy lost to friction between mating threads, while the third term accounts for the energy lost to bearing surfaces during the tightening process. Now evaluate these terms for the example bolt.

In addition to bolting geometry values, consider the published values of friction coefficients for a commonly used paste, lubricant. The definition and values for each variable are noted in Equation 1.

Substituting these into the respective terms they are evaluated and compared in Image 3. Term 1 is the useful work in creating the clamping force.

Image 3. Input energy going into stretching the bolt, and energy lost to friction

The sum of the other two terms is the energy loss to friction.

In this particular instance, with the presumed coefficients of friction, only ~16 percent of the applied energy is converted to the useful work of creating bolt stretch. A total of 84 percent of the tightening load is lost to friction. This explains why only a small portion of the system’s mechanical advantage is realized. The effect of friction should not be underestimated. A torque wrench measures the value of torque being input to the bolt system. It does not reveal how much useful energy is actually being delivered to the bolt.

Clearly, the proper use of lubrication can have a dramatic effect on the success of a bolted flange connection. The liberal use of lubrication is one of the easiest, least expensive, quickest and most effective ways to ensure the targeted clamping load is realized. In the case of gasketed, bolted flange joints, the extra energy transmitted produces a larger sealing stress on the gasket and ultimately results in few emissions and a cleaner, safer environment.


For more information about the right sealing solution for your specific application, contact Gallagher Fluid Seals.

This original article was features on Pumps & Systems website and was written by Randy Wacker, P.E., consultant for Inertech Inc.

Angled Spring Grooves for Custom Spring Energized Ball Seats

A ball valve is a simple and robust valve used in applications and industries across the spectrum. It consists of a ball with a hole through the center that can be rotated 90°.

custom spring energized ball seat

The hole is either aligned with flow and open, or perpendicular to flow and closed. The straightforward, quarter-turn action is fast and simple to operate, and the position of the handle provides a clear indicator of whether the valve is open or closed.

Most ball valves are typically used as a shut-off valve. Many households likely use ball valves at some point in the water supply plumbing.

Not relegated to common plumbing, many industries use ball valves for critical control applications including aerospace and cryogenics. Their reliable operation and high-pressure handling ability make them an attractive solution for many specialty operations.

Seals Inside a Ball Valve

The seals inside the ball valve play an important role in their performance and reliability. There are two main seals in a common ball valve, which are referred to as seats.

The seats are typically machined or molded to match the diameter of the ball and are mechanically compressed against the ball face. Seat material varies by application needs, but virgin PTFE is frequently used for this application.

The Client’s Issue

The customer wanted a very specialized ball seat: utilizing a spring energizer in the seat. While easy to suggest, this would create a significant challenge in how the seal is manufactured.

The customer was looking for a sealing solution for a ball valve in their industrial gas processing plant. The ball valve would serve as a critical shut-off point in the system. The valve would be actuated by an electric motor, and could therefore be operated remotely.

The customer was looking for an improvement in the overall wear life of the ball seats, while still providing consistent and predictable actuation torque. Being motor activated, the torque required to move the ball open or closed was limited—so the friction generated by the ball seats would need to be carefully controlled.

Operating Conditions:

  • Ball Valve Seat
  • Ball Diameter: Ø2.500”
  • Media: Petroleum Processing Gases
  • Pressure: 100 PSI
  • Temperature: -40° to 175°F

The Challenge

Continue reading Angled Spring Grooves for Custom Spring Energized Ball Seats

How to Fight Leakage & Bearing Contamination with the Right Sealing Solution

Consider mechanical seals, gland packed seals, and lip seals.

The drive for operational efficiency, optimization of assets, and adherence to the International Standards Organization (ISO) 14001 Standard for environmental management systems and ISO-50001 standard for energy management systems must always be balanced against the bottom line.

However, it is fair to say in some cases this can lead to short-sightedness when it comes to selecting sealing solutions, with lower cost at point-of-purchase taking precedence over total cost of ownership.

Mechanical seals have been on the market for around 80 years, and while pump design has remained largely unaltered, sealing technology has evolved over time. This has resulted in advances in reliability, operational efficiency, and environmental sustainability.

Traditional sealing options like gland packed seals and lip seals are traditional for a reason. These products are comparatively inexpensive when taking the purchase price into account, and work well in many applications. This article will take a look at the differences between mechanical seals, gland packed seals and lip seals.

Excessive Wear

Leakage, product loss and bearing contamination that leads to premature failure are three common issues with traditional seals.

There is no reason why bearings should not last for their full predicted lifespan, which is typically calculated at roughly 15,250 operational hours. Leakage caused by inefficient sealing is the simple reason why they do not last. With research showing that water contamination of just 0.002 percent—a single drop—in a bearings chamber can reduce bearing life by almost half, it is easy to see why bearing failure is one of the most frequent causes of pump malfunction. The cost of regularly replacing damaged seals and bearings accumulates over time and can escalate if the pump shaft suffers wear damage and must be repaired or replaced.

Another key cost, which is often overlooked, is the number of hours demanded to maintain, repair and replace these components. Continue reading How to Fight Leakage & Bearing Contamination with the Right Sealing Solution

Semiconductor Fab Processes Benefit From Retention Ribbed EZ-Lok Seals

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

Original content can be found on Parker’s Website and was written by Nathaniel Reis, applications engineer, Parker O-Ring & Engineered Seals Division.


When it comes to semiconductor fabrication processes, reducing the cost of ownership is a multi-faceted goal approached from a variety of angles. Tool engineers and equipment technicians take pride in their ability to identify factors that limit tool uptime. One constant headache they face is the mechanical failure of seals in dynamic environments. This can lead to premature downtime or reduced preventative maintenance (PM) intervals, both of which lead to a higher cost of ownership. Fortunately, tool owners have begun to implement seal designs better suited for these dynamic environments: Parker EZ-Lok is a proven solution.

Spiral Failure

picture of spiral o-ring failure

One of the more extreme forms of mechanical failure to be prevented is twisting and spiraling of an O-ring during operation. This occurs with O-rings in dovetail glands where one of the sealing surfaces is a door that opens and closes against the seal. The combination of stiction to the door and stretch in the gland causes the O-ring to roll and twist repeatedly with each cycle, resulting in permanent cyclic deformation. This means that a seal profile with a flat contact surface is vital for this type of dynamic function.

Other designs

The basic D-profile is the fundamental simple shape that serves as the basis of the EZ-Lok solution. The flat portion of the “D” holds the seal in place and prevents rolling, while the opposite, round contact surface focuses the sealing force and helps keep volume requirements at a minimum. These geometric features make for sound sealing function while preventing the drastic spiral damage seen so often in the industry.

picture of d-profile

A standard D-ring is still more limited by volume requirements than traditional seals like O-rings. In addition, a D-ring’s sharp corners can become difficult to install past the top groove radii if the seal is made much wider than the groove opening. On the other hand, a seal made any narrower would be easily removed without intention, such as that induced by stiction to the door. These reasons are why the basic D-profile alone is not the answer to these failure modes.

The Solution

picture of Parker EZ-Lok seal

The solution to these dilemmas is a unique D-shaped profile with a geometry that lends itself to the spacial constrictions of dovetail glands, prevents rolling, and locks into place: the Parker EZ-Lok seal. These seals are designed with special retention ribs placed with precise frequency around the seal circumference that allows for smooth installation and keeps the seal retained in the gland. This design also removes any tendency to stretch the seal during installation, which is often seen with more conventional seals.

The combination of retention ribs with a fundamental D-ring profile makes EZ-Lok the ideal geometry for effective use of the high-performance compounds typically required for aggressive semiconductor chemistries. EZ-Lok seals allow for lower cost of ownership through PM-minimization and reduced seal overhead costs, made possible by effective mechanical design. This is an example of how Parker’s effective design engineering can reduce the cost of ownership and bring premier solutions to the table.


For more information about Parker’s full suite of solutions and sealing products, contact Gallagher Fluid Seals’ engineering department.

Freudenberg Announces New VMQ Materials

When it comes to food, Freudenberg wants to be sure that its sealing materials are free of harmful substances.

In the food processing industry, in order to guarantee food safety, both the food and the hardware that come into contact with it must meet particularly stringent criteria. These guidelines also apply to sealing materials.

picture of food processing plantIn China, specific standards were created in 2016 with the two standards GB 4806 and GB 9685, which deviate from the existing relevant American and European regulations for food-grade materials. To meet the stringent Chinese regulations, FST has now successfully tested two proven VMQ materials: 70 VMQ 117055 and 60 VMQ 117117 for their conformity with Chinese guidelines.

The Chinese standard GB 9685 specifies which ingredients may contain materials that come into contact with food in a so-called positive list. A large number of seal-relevant ingredients that conform to 21 CFR 177.2600 of FDA (U.S. Food & Drug Administration) and European EU (Reg.) 1935/2004 are not listed here. This applies to elastomers. For a global food release, new material compositions must therefore be developed or proven materials tested for their conformity with the specifications.

Global food approvals require extensive testing

The basic requirements for gasket materials as well as sensory tests and migration tests are defined in standard GB 4806. Two of Freudenberg’s newly developed EPDM materials have successfully passed the tests: 75 EPDM 386 and 85 EPDM 387. 

After extensive testing, FST’s two new VMQ materials now meet the requirements of the Chinese standards. As an example: the silicones in the migration measurement in mg/dm2 had a result of <1, and are far below the specified limit of ≤10.

In addition to the EPDM materials which are characterized by media resistance, good processing behavior and a long service life, FST’s new silicones, 70 VMQ 117055 and 60 VMQ 117117 provide grease-resistant material selection for use in contact with food in the Chinese market.


Gallagher Fluid Seals is a preferred distributor of Freudenberg sealing. For information about Fruedenberg, or if you have needs for a custom solution, contact our engineering department.

The original article or press release can be found on Freudenberg’s website.