Category Archives: Compression Packing

The Braid Variations of Compression Packing

picture of compression packingSuccessful fluid sealing of valves and pumps cannot be accomplished without the appropriate sealing device. Whether using mechanical seals or compression packing, one must understand the specific needs of the application.

While mechanical seals in general are considered the superior sealing device, they are more expensive and less versatile than compression packing. Compression packing is more versatile due to the vast selection of materials used to make it and the various ways it is constructed. Materials such as vegetable fibers, man-made fibers, metals, graphite, and hybrids are all used to make packing. Construction types include braided, twisted, wrapped (rolled, folded), extruded, laminated, bulk, and die formed.

Construction types of compression packing each have variations within. This article will focus on braided packing. The most common braiding styles are square braid, round braid, twisted braid, braid-over-core, and lattice (interlock) braid.

Square Braid

The majority of braid types covered in this article are described by a geometric shape. One of the most common braids used to make compression packing is the square braid. Square braid is known to be soft and pliable, relatively loose, and can carry a large percentage of lubrication. Square braided compression packing can be formed from a variety of materials and can be woven as a homogeneous or composite product, where strands are passed over and under each other in the same direction and have a square or rectangular cross-section. Given its soft and loose characteristics, square braid will expand more radially than other braid types, which is especially effective when trying to seal worn, old equipment where voided space needs to be filled. Square braid packing is best used in applications of high speed rotary motion at relative low pressure. Continue reading The Braid Variations of Compression Packing

Braided Packing Materials: From Flexible Graphite To Fiberglass Rope

picture of braided packingIt’s highly likely that, at some point or another, you have seen braided packing in or out of its “natural environment.” Braided packing looks like rope and is cut into rings that wrap around a rod. While packing used to be available in fairly limited styles, the mechanical packing industry has expanded over time, resulting in braided packing that is available in everything from flexible graphite to fiberglass yarn. Let’s dive into this topic, and discuss the different materials from which braided packing is made in this day and age.

Fiberglass Rope

One of the reasons why fiberglass ropes are favored for braided is that it does not burn. It can be used in continuous temperatures, up to 1,000 degrees Fahrenheit. This makes it perfect for products that are going to exist in high pressure, high-temperature environments. Furthermore, E glass in particular consists of more than 50% SiO2. SiO2, as well as B2O3, are prominent network formers, further emphasizing the usefulness of this product.

Flexible Graphite

Flexible graphite is another product used for braided packing, in part because it is made up of 95% to 99% carbon. It is the softest material, and has a score of 1 out of 10 on the Mohs hardness scale, but can resist high temperatures, and has high levels of chemical resistance. While some favor fiberglass rope over flexible graphite, it remains a classic material associated with braided packing.

Ceramic Fiber Cloth

A product known for its ability to withstand high temperatures is ceramic fiber cloth. This particular material is known to withstand temperatures up to 2,300 degrees Fahrenheit — making it even more durable than fiberglass rope. The strength of this particular product means that it shouldn’t be discounted, even when compared to flexible graphite and fiberglass rope.

Ultimately, the types of materials used for braided packing can depend on exactly what the braided packing will be used for, as well as the costs associated with the order and the long-term needs of the buyer. However, when choosing a material, one will not receive poor results when relying upon the materials like fiberglass rope, flexible graphite, and ceramic fiber cloth. There is a reason why these materials have long been valued in the braided packing industry.


The original article was featured on Mineral Seal Corporation’s website and can be found here.

For more information about compression packing and braided packing, contact Gallagher Fluid Seals today.

The Danger of Complacency in Equipment Selection & Installation

Ensuring the correct materials are suitable for the application

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

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

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

Small packing leak can turn catastrophic

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

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

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

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

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

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

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

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

Gallagher Fluid Seals Announces e-Commerce Store

Better and faster access to the seals you need to keep your production running.

King of Prussia, PA. October 29, 2019 /News and Updates/ — Gallagher Fluid Seals (GFS) is excited to announce the launch of its e-commerce store, providing a brand new experience to shop for seals.

“It’s been a complete team effort,” says Chris Gallagher, CEO. “Our team has worked diligently over the past several months to prepare and deliver a state-of-the art e-commerce store for both new and returning customers.”

As the world’s economy has evolved to an online platform, GFS felt seal buying should be easier. Gone are the days of calling in and ordering a replacement seal – or sending an RFQ. This new online experience allows greater and faster access to the seals you need to keep your facility up-and-running.

“Maximizing the ease-of-purchase and visibility of fluid sealing products is imperative to the future of seal buying, and that’s why we are well-positioned to help our customers for years to come,” says Chris.

To start, Gallagher’s e-commerce store will focus on six main product categories:

  1. O-Rings
  2. Gaskets
  3. Sheet Material
  4. Expanded PTFE
  5. Compression Packing
  6. Mechanical Seals

In the coming months, the full product array will be added to shop.gallagherseals.com, providing even more fluid sealing options. Specialty products such as expansion joints, bearings & bushings, rotary seals, and more will be added.

We’re excited about this new chapter in Gallagher Fluid Seals’ history, and we hope you will join us in this journey to make your seal shopping experience easier and more transparent.

Shop our new e-commerce website here:

>> shop.gallagherseals.com

For larger orders or custom-engineered sealing needs, it’s suggested that customers complete a form on our e-commerce website requesting to speak with an engineer or member of the customer service team.


About Gallagher Fluid Seals, Inc.

For 60+ years, Gallagher Fluid Seals has taken pride in being the industry leader for all things seals. Not only was Gallagher the first North American seal distributor to achieve ISO 9001 certification, but year-after-year, GFS takes steps to maintain its status as the leading distributor for fluid sealing products: In January 2019, Gallagher made an additional company acquisition – this time acquiring Quality Seals out of Bethel, CT. This strategic acquisition has been great for customers. It has helped to bolster capabilities and expand product lines while simultaneously opening a custom engineering channel to Quality Seals’ existing customers.

Contact:
Kevin Patton
Marketing & Communications Analyst
610-277-8200

Upgrade from Pump Packing to Mechanical Seals

Mechanical sealing conserves water, improves energy efficiency, and minimizes environmental impact

The environmental performance of products and processes in all industrial sectors increasingly is cause for critical inspection, with sustainability, conservation of natural resources, and reduced environmental contamination concerns influencing equipment design and selection.

Many industrial processes can be addressed to improve sustainability and minimize environmental impact, while at the same time maintaining or reducing operating costs. Implementing energy-efficient and environmentally friendly processes and technologies should be embraced as a priority at the component, process, and system levels.

One aspect of these processes is mission-critical rotating equipment, and specifically centrifugal pumps, which represent a significant proportion of the equipment found in industrial operations. One vital component of a centrifugal pump is the seal around the rotating shaft that passes through a stationary pressure casing or housing. The seal contains the liquid or gas from escaping to the environment.

Sealing systems help maintain acceptable pump efficiency, reliability, energy consumption, water usage, and emissions control. These factors can materially facilitate achieving total-life cycle cost-reduction and sustainability objectives. Sealing performance can be improved for centrifugal pump applications by upgrading from traditional compression packing to mechanical seal technology.

When sealing a centrifugal pump, the objective is to allow the rotating shaft to enter the wet area of the pump without large volumes of pressurized fluid escaping. The pump discharge pressure forces the fluid back behind the impeller, where it is induced to exit by way of the rotating drive shaft. To minimize leakage, a seal is needed between the shaft and pump housing to contain the pressure of the process being pumped and withstand friction caused by shaft rotation.

Compression packing is the traditional means to seal centrifugal pumps, going back more than 100 years. Also referred to as gland packing, it is a braided, rope-like, and lubricated material packed around the shaft in rings, physically stuffing the gap between the shaft and the pump housing, within a stuffing box.

Water leakage and consumption

Charred packingFor compression packing to work, some leakage must be maintained to lubricate and cool the packing material. Therefore, packing rings allow for an adjustable, close-clearance leak path parallel to the shaft axis. As the packing is used, however, some of the lubricant that is embedded into the packing is lost, reducing the packing ring’s volume. The pressure squeezing the rings together is also reduced, increasing leakage.

Periodic adjustment of the packing follower brings the pressure back into specification and controls the excess leakage. In today’s world, however, this maintenance is not always being done at required intervals or adjusted correctly. As the number of centrifugal pumps incorporating the use of compression packing decreases, training for and understanding of packing maintenance has waned.

Consequently, under-tightening and over-tightening of packing rings is a prevalent and growing misapplication of centrifugal pump maintenance, with critical consequences to both water consumption and energy draw.

Under-tightening results in too much leakage. Already, when properly adjusted, packing leakage can amount to gallons of liquid leaked per minute. This can be either aqueous solutions comprised of varied benign or caustic chemical compositions, or particles in suspension or slurry, depending on the process.

The heavier the suspension or slurry content in the pumped liquid, the more water is needed to get packing to work reliably. Typically, a clean external flush is piped into the stuffing box through a lantern ring, which keeps the packing lubricated and cool while flushing abrasives and chemicals.

Normally, some portion of the leakage is released continually into the atmosphere. Under-tightening of the packing rings and use of external flushes increase this atmospheric release proportionately, along with environmental impact potential. Continue reading Upgrade from Pump Packing to Mechanical Seals

How to Investigate Compression Packing Failure Modes

Over-tightening, excessive speed and improper installation can cause a system to falter.

In many respects, troubleshooting and failure analysis of compression packing materials is similar to the investigation of a crime scene. A good investigator knows how to gather clues from many different sources and put them together to understand what has happened. A good troubleshooter uses the same information gathering method, familiarizing themselves with the sealing materials, the process equipment and the systems where they are used.

Start by Interviewing Witnesses

The troubleshooter should seek information from the people who work with the equipment on a regular basis. Seal installers, maintenance personnel, operators, process engineers and others can all shed light on potential causes of failure. Some key questions should be:

  • How is failure defined? Some examples include excessive leakage, overheating, high rate of flush water consumption, excessive friction load and blowout.
  • Is this application the source of chronic seal failures, or was this an unexpected event?
  • Were there any changes to the seal material, the equipment or the overall process that preceded the failure?
  • Were there any system upsets or cleaning cycles that preceded the failure?
  • Can you describe the installation procedure?

Gather Information About the Victim

Knowing the limitations of the sealing product is a key step. The acronym “STAMPS” will help remember the key elements to ensure the right packing is selected for the application.

  • S: Size. Is the correct packing cross-section being used? Are the rings cut or formed to the correct length?
  • T: Temperature. Check the system temperature against the packing manufacturer’s established temperature ratings for the product.
  • A: Application. Some packings are made specifically for rotary equipment while others are intended for valves or static seals. Check to make sure the packing is suitable for the equipment where it is being used.
  • M: Media. This refers to the fluid being sealed. Check with the manufacturer or with compatibility charts to be sure the seal material is compatible with the media. If the media is slurry, abrasion-resistant materials may need to be specified. If the media is toxic, explosive or required to be contained within certain maximum allowable leakage requirements, then a packing must also be selected on the basis of its ability to seal at low leakage levels.
  • P: Pressure. Check the system pressure against the packing manufacturer’s established pressure ratings for the product.
  • S: Speed. Check the equipment speed against the packing manufacturer’s established surface speed ratings for the product. Surface speed is expressed in feet per minute or meters per second and not revolutions per minute.

Investigate the Crime Scene

When possible, observe the equipment while it is running. Can you see, hear, feel, smell or use a sensor to make observations? Smoke, vibration, grinding noises, the scent of burning fibers and system pressure fluctuations are only a few of the clues that can be noticed or measured while the equipment is up and running.

Examine the condition of the equipment. Most packings are robust seals that can handle less than perfect equipment condition, but there are limits to the amount of degradation they can withstand.

Valve stems and pump shafts or sleeves should be checked for scratches, corrosion pitting and general surface roughness. Rough surfaces can damage the sealing surface and result in excessive leakage and quick wear of the seal.

Extrusion of the seal material
Image 1. Extrusion of the seal material

Excessive clearances at the top or bottom of the stuffing box can lead to extrusion of the seal material and intrusion of large solid particle into the seal area (see image 1).

In severe cases, excessive clearance may result in a seal blowout.

Most packings are not meant to function as both a seal and a bearing. In rotating equipment, poor bearing condition may result in shaft runout that “wallows out” the inside diameter of the seal. Misalignment may result in shaft/stuffing box offset that causes one side of the packing set to be heavily compressed while the other side is compressed much more lightly. A similar side loading of a packing set can occur in large horizontally oriented valves where the packing is forced to bear the weight of the stem.

Check to make sure all the parts are in place. During the breakdown, repair and reassembly of equipment it is possible to misplace parts. Equipment might be put back into service without seat rings, bushings, lantern rings, O-rings and other parts that are essential to proper equipment operation.

Look at the seal and the equipment as a part of a big picture.

Consider how this piece of equipment is affected by other equipment and control devices in the system. For example, is there a downstream valve that creates pressure spikes in an upstream pump seal when the valve closes and the pump is still operating?

Continue reading How to Investigate Compression Packing Failure Modes

VIDEO: Garlock Compression Packing

Garlock compression packing is rigorously tested to ensure effective sealing in valves, pumps, agitators, and other rotary equipment. The development of the compression packing line reflects the evolution and innovation in the materials used in its production. Garlock develops and manufactures it’s own technical yarn braided into packing, along with high performance proprietary coatings, that are essential in this age of sealing performance requirements.

Garlock’s product line includes industry recognized Low Emission valve stem packing, leading-edge and award winning pump packing sets like dry-running DSA, and water saving HYDRA-JUST.


Gallagher Fluid Seals is an Authorized Garlock Master Distributor, stocking many styles and cross-sections of compression packing.  Remember, all packings are not created equal, so feel free to contact us if you need assistance determining which packing is best for your application.