Latest Seals Articles

Compression packing has been around since the beginning of the industrial revolution and is still used extensively in types of equipment in which a stuffing box seal is required to prevent loss of process fluids to the environment. While advanced sealing solutions for rotary applications, such as mechanical seals, emerged over time, compression remains an important industrial tool.

Q. What principles drive the pumping action in a controlled-volume metering pump?

A. The pumping action is developed by a reciprocating piston. This reciprocating motion develops a flow profile represented by a sine wave. Actual rate of flow is determined by the following formula:

The phrase “It’s just a small leak” is rarely found in the vocabulary of any maintenance manager, pump operator or pipefitter.

A fact of life is that equipment operators spend more time with pumps than mechanics do. Leveraging this familiarity with equipment, operator-driven reliability (ODR) programs focus on maximizing plant reliability by enhancing the techniques operators use to monitor the equipment for which they are responsible.

Rubber expansion joints are used in piping installations to compensate for thermal growth, relieve piping stress during operation, and reduce vibration and noise caused by rotating equipment. While a rubber expansion joint can compensate for pipeline misalignment, this compliant product has installation and operational limitations.

The life of equipment, such as compressors or pumps, depends on the functionality of individual parts, including seals. As the useful life of a seal increases, so does the reliability and robustness of the pump. Premature seal failure is one of the reasons for growing maintenance costs and overall cost of ownership.

Cryogenic products are produced globally and are critical to industries such as refining, steel, medical, plastics, chemical, petrochemical, brewing, welding and fuels. Liquid nitrogen (LN2), liquid oxygen (LOX) and liquid argon (LAR) are some of the specific liquefied gases used in these products. During cryogenic production and distribution, operating conditions can be extreme.

Maintenance personnel usually dislike rotary seals. This is because replacing a low-cost oil seal requires dismantling a whole piece of equipment.

Pump manufacturing companies have made strides in improving design, efficiency and energy usage in recent years through developments in impeller profile and the use of optimized motors and variable frequency drives. All of these changes enhance end users' bottom lines by reducing energy costs.

In the U.S. and abroad, governments, regulators and third-party activist groups are considering policies and actions that could have implications for the sealing device industry. The passing of the Clean Air Act in the early 1990s was a watershed moment for the industry.


For those of you old enough to remember Lawrence Welk, you’ll notice that the title of this brief column is the final quote from his show’s closing song. I am still a loyal fan of his reruns today.

Lev Nelik answers a reader's question on thermodynamic sub-processes that are highly time dependent

A reciprocating power pump, as depicted in Figure 1, is a displacement machine. It has characteristics that are different than a centrifugal pump.


More than 6,500 kilometers separates Frankfurt, Germany, and Dubai, UAE. To the average traveler, this distance might sound intimidating.

Part one of two: This column discusses valves and fittings and evaluates how these devices affect the operation of piping systems.
Cahaba Media Group

See also:

Upstream Pumping

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