eclipse
- November 09, 2023
Back-Up Rings
Back-up rings serve an important role in world of seals. While the design principle and construction are incredibly simple, they greatly extend the usefulness of the most common and prolific sealing device in the world: the O-ring.
Back-up rings are aptly named as they do just that: they back-up an O-ring.
Back-up rings are commonly nothing more than a ring of polymer meant to space the O-ring away from the extrusion gap in hardware. By blocking off the extrusion gap, the pressure-handling ability of an ordinary O-ring is greatly increased.
Solid or split back-up rings out of virgin PTFE can usually be found on the shelf, and are largely considered commodity items.
- December 29, 2022
In the world of engineering, machinery, and mechanical systems, dust can be the difference between a reliable piece of equipment and disaster.
Dust can cause major damage to cylinder walls, rods, seals and other components inside of machinery. And if you’re not careful, dirt, mud, debris, and water can all cause damage as well.
These foreign contaminants are real problems for mechanical systems, especially as they build up in small quantities over time. A single particle of dust today may be no big deal. But a speck of dust per day will eventually become enough of a presence to cause serious issues, like friction, surface wear, and imperfect seal contact between surfaces.
These issues could compound until the mechanical system experiences a complete failure. And in some applications, like in automobiles and aircraft, failure is simply not an option.
Beyond those industries, many types of equipment need to stay clean on the inside, even when things get extremely messy
- October 20, 2022
Channel Seals for Hydraulic and Pneumatic Systems
The Channel Seal (or Cap Seal, as it’s often referred to), was one of the earliest forms of Polymer or Teflon sealing in the seal industry.
The product is easily applied. It didn’t replace the O-ring, but instead offered improved life while reducing drag.
In doing so, hydraulic and pneumatic systems operated cooler and quieter, while improving overall performance of the product.
Evolution of the Channel Seal
Before the Channel Seal, the Backup ring was established. The first Backup rings started out as leather,
- July 16, 2021
As the operating parameters of industrial technologies and manufacturing processes get more extreme, the need for optimal sealing solutions become that much more important.
Elevated temperatures and pressures, higher speeds, extreme environments, faster gas decompression, and aggressive medias all make sealing more critical. This extends right across static, reciprocating, rotary, and oscillating applications.
This challenge has been met very effectively by the inventive addition of energizers to seals. Energized seals give the ultimate performance in the most demanding conditions and critical applications.
Spring or o-ring energizers can extend the normal limits of PTFE and plastic materials to deliver durable ultra-tight sealing capability. Here’s a rundown of how energizers work and how they can elevate your next sealing challenge.
- October 20, 2020
When considering polymer jacketed seals — especially PTFE-based products — some form of energizer is typically required. These types of seals are usually specified to operate both in very high pressures, low pressures, or even in a vacuum.
At certain pressures (typically above 100psi), the system pressure will energize the seal and prevent leakage. But at low pressures, additional energy is required to force the jacket material to mate with the hardware.
The solution to this is to add a spring to the seal. The spring provides the needed sealing-energy to prevent leakage at low media pressures.
When considering a high pressure-application, there are start/stop conditions where the system is at low pressure. If the seal allows some amount of leakage at low pressure, it becomes possible for that leakage level to increase once as the pressure builds.
This phenomenon is called “blow-by.” Once it occurs in a system, it’s difficult to get the seal to seat and seal correctly.
Canted Coil Spring Energizer
There are several types of energizers to consider when specifying a seal. These can be as simple as an O-Ring or some other elastomer.
- September 25, 2020
“How much pressure can this seal handle?”
The answer to this question depends on a number of parameters and conditions. But the principle limiting factor in the pressure handling of any seal system is the extrusion gap.
Commonly referred to as the “E-Gap,” the extrusion gap is one of the most critical design aspects in any high-pressure application. Seal design, type, and material are all influenced by the extrusion gap and the desired pressure handling capability.
What exactly is an extrusion gap, and why is it so important in the successful design of a sealing system? Let’s find out.
The Basics: What is an Extrusion Gap?
In terms of sealing systems, the extrusion gap is defined as the clearance between the hardware components.
In a piston configuration, this would be the clearance between the piston and bore. In a rod configuration, this is the clearance between the rod and housing it’s passing through.
The extrusion gap can be expressed in terms of radial or diametral clearance, which can lead to some confusion. Our partners at Eclipse define the E-Gap by stating it as the radial clearance. The radial clearance is equal to the diametral clearance divided by two.
It’s important to note that while hardware components might be machined to have a specified clearance, this gap might not be perfectly realized or maintained.
- September 01, 2020
When it comes to maintaining a high-functioning rotary shaft, you need to select the appropriate lip seal.
The shaft seal protects the rotary shaft from contaminants such as dust and dirt, and it keeps water out and lubricant in.
A rotary seal, also known as a radial shaft seal, typically sits between a rotary shaft and a fixed housing — such as a cylinder wall — to stop fluid leaking along the shaft. The rotary seal’s outside surface is fixed to the housing, while the seal’s inner lip presses against the rotating shaft.
Common applications for shaft seals include motors, gear boxes, pumps and axles. They’re also increasingly used for food and chemical processing, as well in pressurized gas applications.
Three of the most important considerations when the choosing the best lip seal for a rotary shaft are:
- The material the seal is made of,
- the hardness of the shaft’s surface, and
- the roughness of the shaft’s surface.
Here’s your quick go-to guide on how to achieve optimum performance and longevity for your seals and shafts, ultimately minimizing the risk of seal failure. Presented by our partners at Eclipse Engineering:
- June 12, 2020
Eclipse has been working hard during the Covid-19 downtime on finding solutions to issues that customers have brought to the table over the past few years.
Many new designs have been sent into testing while focusing on processes that will help improve productivity and lower costs.
The MicroLip™ is an example of a viable solution to rotary seal issues that many customers have struggled with. This is especially true when the order volumes are relatively low or the shaft diameters are small, such as with encoders or chemical-processing facilities.
The Eclipse MicroLip™ Prototype Program
When moving from rubber to Teflon lip seals, Eclipse has found that the cost to bring the product to market is often a hindrance. The high cost is due to tooling and the number of pieces that must be manufactured to make the product viable in the prototype phase.
Because of this, many customers sneak by using inappropriately-applied rubber lip seals to solve rotary seal problems.
MicroLip™ seals have proven to be a powerful component in rotary services. Since the MicroLip’s inception, it has been applied to a variety of applications including mobile hydraulics, robotics, surgical drills, and semiconductor processing and encoders.
Over the last 3 years, Eclipse has designed and manufactured various styles of MicroLips in diameter sizes of under 1/8 inch (5mm) and over an inch. Since the components of the MicroLip™ can be machined, Eclipse has made the seal in quantities of less than 10, and batches in the thousands.
- May 26, 2020
When designing for low temperature sealing, the first step is to define the temperature range that the seal will be operating in.
Typically, cryogenic as seals are those that are operating below -65 Fahrenheit. Gallagher's partner, Eclipse, chooses this benchmark because they currently have elastomers that have a usable TR10 value at this temperature.
When designing at this level — with high temperatures around 300 Fahrenheit — an understanding of what level of leakage control is required on the low temp end. Seals that operate in aircrafts must function within this range.
However, there may be an allowable leakage rate which allows for reduced drag. When requiring zero leak, the drag in the system is often increased to support some elastomeric contact with a dynamic surface. In the case of static seals, elastomers span this range although increased squeeze may be necessary.
Eclipse Engineering routinely designs in the range indicated above.
While -65 Fahrenheit is extreme cold, it's not considered cryogenic. Liquid nitrogen at -320° Fahrenheit (-195°Celsius) requires special hardware and seal material consideration.
To begin, many projects and applications don't utilize lubricant in dynamic applications. To improve sealability, a better-than-average surface finish is required.
Surface finish often holds lubricity. But without this, a smooth finish reduces friction, improves life, lowers drag, and improves sealability.
Static seals are often required to have leak rates approaching zero; meaning hardware considerations and surface can be even more important. This may mean polishing the groove, which in some applications can be very challenging.
Cryogenic Seal Materials
The next criteria are the seal materials. Elastomeric materials lose their flexibility at these extreme temperatures, so Eclipse relies on polymer-type materials to bridge the gap. When we experience temperatures below -180° Fahrenheit ( -195° Celsius), that's when it becomes wise to move away from basic PTFE to modified fluoropolymers such as PCTFE, known for operating down to -460 Fahrenheit.
- April 29, 2020
The coronavirus has prompted all of us to do everything we can to protect ourselves from catching and spreading the virus. We are all taking important safety measures to maintain a clean and uncontaminated home environment, and limiting our exposure to a potentially hazardous outdoor environment.
In this blog, our partners at Eclipse will be examining the role that seals play throughout a pandemic. The very role of seals is to keep a certain environment in, and certain environment out, similar to how we are living these days.
In Eclipse's last blog, they wrote about boundary seals in aircraft and how seals allow the aircraft to be pressurized. In the research lab, a different style of boundary seal is required to keep the outside environment out.
Labs all over the world are working toward preventing the spread of coronavirus. Scientists are working with test equipment to find a cure and a vaccine to prevent not just the spread of this virus, but other viruses which we’ve not yet seen.
When we design seals, we must consider keeping something as small as a single cell from entering a test chamber. Last week, Eclipse received a call directly from a customer building a prototype ventilator to be built in volume to help support patients suffering from coronavirus.
The client requested that Eclipse's engineering and manufacturing team turn an 8-inch (203mm) seal around from concept, design, and finally produced and shipped in less than 4 hours — and they made it happen.
Keep reading to explore the important role that seals play in research equipment as scientists seek to find the cure for coronavirus and beyond.