Last updateMon, 10 May 2021 4pm

Putting the “P” in PVF

Of course, the “P” in PVF stands for pipe, those long round things with the hole down the middle! Learning a little bit more about the pipes that connect to your valves will help you as a valve professional.

First, we need to understand how pipe is sized. Pipe is measured by utilizing a dimensionless number known as nominal pipe size or “NPS”. These sizes run from ¼ inch to above 72 inches. If you take a caliper to a 1 inch NPS pipe you will be surprised to see that it is not 1 inch in diameter, rather, it is actually 1.315 inches in diameter. This oversize dimensioning applies to pipe through NPS 12 inches. For diameters 14 inches and above, the NPS is the actual outside diameter. When it comes to dimensions, pipe should not be confused with tubing. Tubing size is equal to its outside diameter.

Advances in Mechanical Seals

Manufacturers of mechanical seals today are constantly working to engineer longer-lasting, safer, easier-to-use and lower-emission seals for the benefit of seal users, the products they produce and the environment. Technology can be an enabling key to mechanical seal reliability, but it is not the only key. Without knowing the true process conditions, understanding interrelated effects of the larger system, and operating the system properly, good technology applied badly may not ultimately improve reliability.

Use of Hard Coatings for Valves

What types of coatings are available for valves in severe service abrasion service?
Valves operating in this type of service require enhanced durability and corrosion resistance. The coatings widely used for valves include HVOF, hard chrome and D-gun, all of which provide a hard surface with much better resistance to abrasion compared to uncoated parts.

How to Select a Valve Controller

Process manufacturers are faced with multiple considerations when choosing a valve controller or switchbox that will best meet their application needs. Key aspects to consider include product endurance in demanding application environments, agency certifications, ease of installation, maintenance requirements, and product support.

Water Hammer—Check It Out

Have you ever been in an area of the plant that had just shut down a pump, only to hear an explosive sound a few seconds later? The noise you heard was the pump check valve, accompanied by the water hammer, or reverse flow, that slammed it shut.

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