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The Role of Seals in the Quest for a Coronavirus Cure

Cliff • April 23, 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.

At Eclipse, we’ve been interested in examining the role that seals play throughout the pandemic. The very role of seals is to keep a certain environment in, and certain environment out.

We recently 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, we received a call from a customer building a prototype ventilator to be built in volume to help support patients suffering from coronavirus.

The client requested that our 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 we 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.

Seals in Test Equipment

Oftentimes the lab equipment has its own environment, such as an inert gas or some other purging environment to keep the outside world from contaminating the specimen being tested. These types of seals can be static or dynamic.

Static seals are typically used to provide a barrier to the outside world and maintain an environment within a chamber. Dynamic seals, on the other hand, allow for a change in environment by changing the pressure, or allowing the flow of fluids into the environment.

This could include pressurizing the sealed-off environment to allow a further change in how the specimen reacts. The chamber itself may include seals to capture heat and cold for processing the specimen.

When we design for test equipment, we must consider not just the first test run in a chamber but ultimately many tests, so seals must have the capacity to be cleaned or sanitized.

An autoclave is often used to thoroughly clean a test chamber. The seals in the chamber must be able to withstand heat, steam and gamma radiation to insure the next test sample is not contaminated by the previous sample.

Designing and Manufacturing Lab Seals

We take into consideration all of the factors explored above when designing our seals for lab equipment. The number of seals in any order and how they’re going to be installed is considered for the purpose of manufacturability.

Lab-type equipment also often requires seals with extremely small cross section and diameter to ensure that loss of volume displacement is extremely small during testing.

Manufacturing seals to 1mm ID allows for volume displacement during the injection or titration to be extremely small and accountable. We normally use materials like Teflon or PTFE and load the seal with springs, like a Canted Coil spring , which affords us the ability to make small seals in very small envelopes.

Seals like these are often found in test equipment for High Pressure Liquid Chromatography , or HPLC. These seals are often used with pistons made of ceramic. That means low friction is extremely important, as pressures may reach over 300 bar as the fluid is pushed through a filter bed.

Again, contamination of the sample is of utmost importance, so static boundary seals around the test chamber are critical to ensure the validity of test results.

Best Material for Lab Seals

These boundary seals are often made of rubber. However, when we consider the cleaning fluids, autoclave, or gamma radiation, this often makes standard rubber boundary seals unusable.

Spring energized seals can be a promising answer. Spring energized seals have extremely low porosity, and allow for metal springs which will maintain a constant force against the outside environment. Plus, these seals have no problem tolerating the operating environment along with the rigors of cleaning.

These seals are often custom-designed to support the optimal design of the test equipment. Seals can be manufactured to easily be extracted and replaced without damage to the test equipment or other seals in proximity.

Eclipse Engineering custom-designs seals for virtually every application under, on, and off the planet. But today, we’re dedicated to helping scientists all over the world find a cure for coronavirus.

Eclipse Engineering is engaged in keeping those segments of our economy such as food, pharmaceuticals, and chemical processing in place for our everyday lives to continue safely. When called to action, we’re here to support your needs.

By Doug Montgomery January 17, 2025
Eclipse deals regularly with challenging sealing applications from all industries. High pressures and speeds create unique sets of conditions where seal design and material properties are pushed to the limit. While reciprocating applications can certainly test seals to the edge of capability, often times rotary applications can present the greatest challenge to seal integrity and wear life. Unlike reciprocating configurations where the seal is acting on a different part of the shaft or bore throughout it’s 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 applications. Extreme localized heating can have negative affect on both seal and hardware life. Rotary applications also pose sealing difficulties due to the simple fact that surface speeds can be much higher than in reciprocating systems. A simple electric motor can operate at very high rpm, while long stroke, high speed reciprocating machinery is a major piece of equipment that is far less common (though Eclipse also has sealing solutions in a number of these situations). A customer approached Eclipse with an application that was beyond the scope and capability of any standard, off-the-shelf rotary seal. This sealing system would require a combination of both wear resistance in high-speed rotary, as well as excellent leakage control and sealability. Two factors that, more often than not, work in opposition to each other. The Customer Issue The customer was developing a test system that required an electric motor shaft passed through the wall of a large vacuum chamber. The testing apparatus needed a sizable motor to meet the speed and torque requirements. Adapting the motor to operate inside the chamber would not be practical due to contamination and motor cooling concerns. Therefore, the motor would have to be placed outside the chamber and a driveshaft would have to go through the chamber wall. Which, of course, would need a seal. Operating Conditions:
 Rotary Shaft Seal
 Shaft Diameter: 2.5”
 RPM: 7,500 RPM - unlubricated
 Pressure: Vacuum internal side / 1 ATM external side Temperature: 40° - 90°F The customer knew any kind of off-the-shelf rotary seal with a rubber element would not last any amount of time in the combination of speed and a dry running condition. They also knew a single lip PTFE seal would likely not meet their leakage requirements. Therefore, they turned Eclipse for a custom sealing solution.
By Doug Montgomery November 25, 2024
Eclipse has engineered sealing solutions for applications all over the planet and in a plethora of environments. From the bottom of the ocean to orbiting the earth, Eclipse is challenged by the unique conditions in each application. Whether it be extreme temperature and pressure or severely caustic or abrasive media, Eclipse has a solution for most every sealing problem. One distinct environment presents a particularly challenging set of circumstances for seal design – high radiation. Eclipse’s primary seal material choice for many applications is PTFE and PTFE blends. With all the wonderful attributes PTFE possesses as a seal material, radiation resistance is not one. In high radiation environments PTFE’s properties can degrade to essentially rule it out as a suitable material. The options for effective sealing materials that are also radiation resistant becomes very limited. The seal designer is therefore confronted with creating a seal that is expected to perform in every way a typical PTFE seal operates, out of materials that are not as favorable to sealing. This is where Eclipse’s engineering experience and expertise in seal design come to the forefront. The Client's Issue Eclipse was approached by a customer that was looking for a seal solution for a sensor used in a nuclear application. It would be operating in an environment with both high temperature and high Gamma radiation. Operating Conditions:
 Reciprocating Rod Seal
 Rod Diameter: Ø1.000
 Stroke: 1.5”
Cycle Rate: 2-4 cycles per minute
 Media: Air, Salt Water Mist
 Pressure: 100 PSI
 Temperature: 70° to 450°F
 Gamma Radiation Exposure: 10^6 rads
By Doug Montgomery November 14, 2024
Technological advancements in the area of robotics have led to more and more life-like creations existing only in works of science fiction a few decades ago. Development in autonomous logic processing and sensing allows bipedal robots to walk over uneven ground, up and down stairs, open doors and carry loads. Fast response to dynamic and unpredictable real-world environments is critical for the future use of robots in true-life service and practical employment in the years to come. While software and sensor development remain the primary focus of most research, the physical mechanics of next-gen robotics are also continually progressing. Physical components and control systems such as hydraulic pumps and cylinders, servo motors, and structural members are under pressure to continually be lighter, stronger, more efficient and less expensive. Increased demands on the physical components facilitate the need for innovative solutions in design and material usage. Advancements in construction and technology have spilled into all areas of robotic mechanisms and the many seals located throughout the system need to meet the challenges of tomorrow. Eclipse has been at the forefront of this research and has developed innovative solutions pushing the boundaries of conventional sealing devices. MicroLip™ by Eclipse is a prime example of most demanding applications forging new technologies in the sealing world. The Client's Issue Eclipse was approached by a leading robotics company looking for a sealing solution operating under a challenging set of conditions. While many components of tomorrow’s robotics are now controlled and actuated by servo/stepper motors and various electronic devices, the heaviest and most powerful movements are still driven by traditional hydraulics. The constant demand for more powerful hydraulic actuation in ever deceasing size and weight requirements has put tremendous strain on component design. But if robots are to progress to the point where they are usefully employed in the world, high power in a compact design is necessary. A robot, for example, used to survey and assist in a disaster zone too unstable for normal rescuers, must fit through doorways and over obstacles yet still be physically strong enough to render assistance. Large hydraulic systems are capable of moving extremely heavy loads but size and weight constraints of a humanoid size robot limit potential. The robot’s internal power supply to drive all components is also a limiting factor. Our client was developing a new hydraulic pump to drive all major motion aspects of their robotic systems. Their main objective was to minimize the pump’s physical size as much as possible while increasing output and improving power consumption efficiency. This means higher pressures and speeds on increasingly smaller and lighter components. Application Parameters: Shaft Diameter: Ø9.5mm Seal Housing Envelope: 5mm radial cross-section by 6mm axial width Rotational Speed: 3,500 RPM nominally; 6,000 RPM max Operating Pressure: 125 PSI min, 225 PSI nominal, 350 PSI max Surface Finish: 0.04µm Media: Hydraulic Oil While the above combination of pressure and speed might present difficulties for any conventional seal alone, the client’s extremely small physical envelope to house the seal further complicated the matter. If that wasn’t enough, the application presented the additional sealing challenge of up to 0.003” [0.08mm] of shaft runout. As part of the downsizing of all components in the pump, shaft support bearings were minimized leading to the possibility of runout. The wobbling effect of the shaft creates problems as the sealing lip has follow a moving, uneven mating surface, therefore potential leak-paths are created. Wear life can also be compromised due to higher concentrations of uneven loads. The combination of high pressure, high speed, high runout and minimal gland size present a worst-case scenario for a typical seal. Unsurprisingly, the client faced leakage of hydraulic fluid after only short periods of service with any conventional seal they had tested. Eclipse knew the had the perfect solution for this application. One developed to handle such extreme rotary sealing conditions: MicroLip™.
By Doug Montgomery October 14, 2024
How Eclipse reverse-engineered custom PTFE gaskets to restore a brewery’s historic equipment, ensuring leak-free connections and consistent, quality beer production.
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