As we learned last month, carbon/graphite fiber packings have proven to be effective solutions to many common sealing applications.
What factors should be considered for stainless steel fasteners in bolted flanged connections?
The focus has been on the main source of the emissions—valve stem packing. Several companies have evaluated current industry standards and have crafted testing protocols specific to their application requirements.
What are the current industry best practices for the assembly of bolted flange connections?
A discussion of current compression packing technology will help set the stage for an example of how this can be accomplished. Compression packing is still widely used to seal rotating equipment such as pumps.
Mechanical sealing systems can be compared in a number of ways. Obviously, one of the more important areas is reliability.
Gasket manufacturers are frequently asked to provide gaskets that comply with Food and Drug Administration (FDA) regulations. This is a broad and complex area and frequently extends beyond food processing plants to those involved in the making of pharmaceutical products. The information that follows will help explain some of the requirements for FDA compliant gaskets.
Blow outs can be avoided with proper gasket selection and installation procedures.
It is important to understand that pipe strain is one of the leading causes of premature pump failure. Pipe strain can cause "failure" of the packing or mechanical seal since they are both sensitive to misalignments introduced by pipe strain.
Gasket stress is a term commonly used to describe the unit load on its surface. It is one of the most important parameters of a bolted joint because it directly impacts the ability of the gasket to seal.
If stress analysis can ensure that piping loads are within ASME limits, why are rubber expansion joints needed?
Today's pipe stress analysis software provides engineers with a tool for designing complete piping systems and performing structural analysis in compliance with ASME and other well-known piping codes.
Application and maintenance of the manufacturers' recommended torque to valve packing is critical to meeting emissions requirements and long service life. While approaches to the application of torque for braided and die-formed packing may be different, the generally accepted practices are important to all valve packing. Consultation with the packing manufacturer on specifics of the application can help to ensure reliable performance.