Every year, nearly 1 in 6 people in the U.S. get sick (~48 million people), 100,000+ are hospitalized, and 3,000 die from foodborne illnesses or diseases, according to data from the CDC. Though this is largely a preventable problem, it still poses a significant public health burden.
Although one might think the relevancy of the FSMA is more geared towards the food or beverage product itself, this act is actually vital to the processing operations in food, beverage, and pharmaceutical industry.
Over time, exposure to continuous vibration, volatile temperatures, and corrosive chemicals can cause O-rings in processing operations to become worn and eventually fail. When this occurs, particles of rubber from seals and gaskets can shear-off and migrate through sanitary systems, piping mechanisms, or by other means, eventually entering the product stream.
In some cases when a problem is discovered, equipment must be shut down and visual inspections conducted to find the source of contamination. This leads to downtime, lost production, and lost revenue. If the contaminant ends up in the supply chain, even more risk is assumed due to recalls or litigation.
Sealing can often be a frustrating challenge when dealing with flow batteries. Determining what materials are compatible with certain chemistries or developing a profile that provides optimal sealing under available compression can be a time-consuming task for those outside the sealing industry. A trial and error approach can have a significant overall cost impact through multiple prototype iterations, prolonged testing, and ultimately, delaying product commercialization.
Parker’s design and material engineers can provide support to your team in the critical, early stages of product development. With hundreds of engineered elastomeric materials to choose from, our team can identify and recommend a compound that works with your specific electrolytes or other fluids. With the exceptionally long lifetime requirements of flow batteries, our homogeneous rubber provides the elasticity needed to handle the many charge-discharge cycles the battery will see in its life.
Radial shaft seals, also known as lip seals, are used to seal rotary elements, like a shaft or rotating bore. Hydraulic pump seals, axle seals, valve stem seals, or strut seals are the most common examples the average person would recognize.
Radial shaft seals are used in a variety of applications and perform two essential functions: the first is to avoid leakage through retaining the bearing or system lubricant; the secondary function is to avoid the contamination of the system by outside impacts (external particles or environmental issues).
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.
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?
Gaskets from NA 1122 Compressed Non-Asbestos Sheet Material
For nearly five decades, the fluid sealing industry attempted to pinpoint an ideal solution to replaced asbestos-based gaskets… until recently. TEADIT’s NA 1122 is a Compressed Non-Asbestos sheet rubber specially formulated for severe-service applications.
NA 1122 sheets provide a new option that meet the needs of users while helping to avoid the hazards of using asbestos-based gaskets in the workplace.
TEADIT style NA 1122 was developed to exhibit superior thermal stability during extreme thermal cycling applications. It is specifically recommended for saturated and superheated steam services but has also proven itself to be very effective in sealing liquid petroleum derivates, ethanol, chemical products and other fluids.
The Difference Between Thermal Conductivity and Thermal Impedance
Thermal Interface Materials (TIMs) are useful for thermal management in electronic components, as they enhance heat transfer from a heat-generating component to a heat dissipater, or heat sink. One important aspect when selecting a TIM for your application is knowing the material’s ability to transfer heat, which is often given by way of thermal conductivity and/or thermal impedance.
Across the industry, manufacturers often publish thermal conductivity in units of Watts / meter-Kelvin as well as thermal impedance in units of °C – inches2 / Watt on their datasheets. So, what is the difference between these two, and how should you consider them when selecting a TIM?
Thermal conductivity is a material property and describes the ability of the given material to conduct heat. Therefore, when a material’s thermal conductivity is high, the material is a better thermal conductor. This property is independent of material size, shape or orientation in a homogeneous material, and because of this, thermal conductivity is an idealized value.
To understand thermal impedance, we must first understand thermal resistance and thermal contact resistance.
Metal hose applications can be tricky. Hoses can fail or have a variety of other problems due to a few different factors: improper installations or outside factors from the surrounding piping system. In this video, Erik Kane, Hose Master’s Product Specialist, discusses various do’s and don’ts when installing metal hose. Follow these tips and more to help maximize the life of your hose and optimize your safety.
This video was produced by Hose Master and can be found on their Youtube channel or on their website.
Gear motors, pumps and stirring units keep process material in constant motion in the process industry’s production facilities. A large number of shaft seals are used at drive shafts to keep liquids securely within the equipment. But leaks may be more likely to occur if the pressure acting on the seals becomes too great. Freudenberg Sealing Technologies has developed a new rotary seal, the Gerromatic, which has a wave-shaped sealing lip. This increases the maximum amount of pressure that can be applied. The sinusoidal contact path also reduces friction and provides self-cleaning, which extends operating life.
In the process industry, including the food and beverage sector, shaft seals used in equipment mostly have a rotation-symmetrical seal lip, which abuts the rotating shaft with a groove-like contact pattern. During wet-running, this can cause the medium to be displaced at the contact surface. The seal then runs in a more or less dry condition, leading to increased friction and higher temperatures. The increased friction increases wear and reduces the efficiency of the equipment. The accompanying rise in temperature is not desirable, especially when the process media are temperature-sensitive. If the seal lip is also exposed to high temperatures at high rotational speeds – for example, due to a process material that applies pressure to the seal lip in a vessel with a stirring unit below it – the lip can fold down on the low-pressure side, which would result in immediate leakage and the seal’s failure.