The client came to our partners at Eclipse with a challenge: for the sealing requirements of their existing spring energized seal to provide optimal performance in a “worst case” scenario.
The client had an issue with outside seals failing at the deepest possible ocean depth and at max temperature of the instrument.
When tested, the seals were failing at the max temperature of 300°F.
Our partner at Eclipse was approached by a valve component manufacturer for a sealing solution for a heavy-lift expendable launch vehicle.
The valve was used in the Hydrogen fuel side of advanced rocket boosters. These boosters are designed to carry the next generation of both cargo and manned exploration vehicles into deep space.
With ever increasing payload requirements and intensive cost sensitivity, rocket booster design and technology has been advanced to meet the demands and requirements.
Being commodity items, U-Cups are readily available in a number of materials and can be found on the shelf from multiple distributors and manufacturers in many standard sizes.
Named for the shape of their cross-section, a U-Cup’s design will be pressure energized increasing sealing effectiveness when compared to a standard O-Ring.
This means as pressure increases, the sealing lips are continually forced into the mating hardware surface, ensuring good contact at all times.
The simple and easily moldable design is an effective sealing solution to many systems in both hydraulic and pneumatic applications. Modifications in lip thickness and inclusion of an O-Ring Energizer can tailor sealing loads and wear life to specific situations.
A key advantage to an elastomeric U-Cup is the relatively small and simple hardware space needed.
Shortly after the discovery and use of PTFE as a seal material, the need for a secondary energizing method became apparent. Unlike rubber or urethane which possess elastic and spring-like properties, PTFE will not return to its original state once deformed.
This is obviously not a desirable trait for sealing material, especially in dynamic sealing applications. PTFE seal designs were soon developed to incorporate energizing elements such as O-Rings and metallic springs. These energizers ensure the PTFE seal is always in contact with the sealing surface.
Our partners at Eclipse utilize three different spring types to internally energize PTFE and other polymer seals, each with its own advantages and drawbacks. Below we’ll discuss in detail some of the pros and cons of Cantilever V-Springs and
While reciprocating applications can certainly test seals to the edge of capability, rotary applications can present the greatest challenge to seal integrity and wear life.
Unlike reciprocating configurations where the seal acts on a different part of the shaft or bore throughout its operating range, rotary seals must operate on the same sealing area continuously.
This makes things like heat rejection much more difficult — especially in unlubricated or dry running
The current global electric motor market is valued at more than 100 billion dollars and is slated for continued growth in the decades to come.
It’s estimated that more than 30 million electric motors are produced every year. The increased development of robotics and automation in many industrial processes as well as demand for numerous consumer applications continues to fuel growth.
The recent push and increased adoption of electric vehicles, including everything from electric bicycles to automobiles is a prime example of the expanding need for electric motors.
The oil and gas industry poses some of the most challenging seal applications for any seal designer. This is largely due to the varying chemical compatibility of fluids, and extremely high temperatures. The fluids often contain solids, which tend to be extremely abrasive. And applications are usually at high rotary speeds with extreme pressures.
This combination creates PV values (pressure x velocity) often reaching the limits of the seal materials. On top of these extremes, as seal designers we are also faced with containing fugitive emissions from valves and rotary equipment, in a very hostile environment like the oil field.
That’s where the rising stem valve has provided numerous solutions in the oil and gas industry.
“Green energy” or renewable energy is collected from renewable resources and replenished by the simple existence of the planet.
Some examples are energy from the sun, wind, tidal wave and geothermal heat.
The process of energy from renewable resources is the conversion of these different forms of energy into electricity. In the case of geothermal energy, it could be electricity or heat transfer for heating and cooling of a structure.
One common theme in the development of seals for green or renewable energy is that the seals have extremely low drag.
Because we typically harness small amounts of energy from these various sources, a high drag style seal can completely negate the gain of energy we are trying to harness.
Spring Energized Polymer Seals and O-Rings are very different products, yet they can ultimately accomplish the same goal of sealing a system.
The humble O-Ring is, in simplest terms, a ring of rubber. A Spring Energized Seal consists of an engineered plastic jacket, usually a PTFE blend or UHMW-PE, and a metallic spring element. One is made in quantities of tens of thousands and then stocked on a shelf, one is machined and assembled per individual order.
While both are seals, their commonality in design, intent, and functionality is limited. The applications where each is successfully employed can be very different.
While seal performance, leakage control, and wear-life characteristics are frequently discussed, one critical aspect of a successful sealing system is often overlooked — how a seal is contained in the hardware.
Whether you want to call it a gland or a groove, the physical space for housing a seal is an important part of the system’s performance. The type of gland greatly dictates the ease and even the possibility of seal installation. Certain seals demand specific gland types, so it’s essential to take these requirements into account.
Below we’ll discuss the most common types of rod and piston glands and what seals work best for each one.