2 . In some wastewater applications , combining different packing materials may be necessary to balance performance and longevity . A dual packing system , for example , combines two types of packing : one designed to handle abrasive materials and another with lower friction and higher heat dissipation . For example , a dual packing system could consist of the first two packing rings ( closer to the impeller ) being a synthetic fiber packing style , highly resistant to abrasion . The subsequent packing rings could then be graphite and PTFE to minimize energy consumption and ensure smooth operation . π www . valve-world . net Valve World November 2024
SEALING WASTEWATER APPLICATIONS
Highly resistant synthetic fiber packings
For the most abrasive wastewater applications , such as those containing heavy slurries , highly resistant synthetic fiber packing like Teadit style 2773 is recommended . These packings offer exceptional abrasion resistance and can withstand harsh operating conditions . Style 2773 , for instance , is primarily composed of phenolic fibers and impregnated with PTFE , graphite , and similarly heat-resistant silicone oil . Both styles provide excellent options for handling varying levels of abrasiveness .
Seals for pump applications
It is important to note that the packing used for valve stems often differs from that used in pump systems . Valve packing is typically designed to eliminate visible leakage entirely , providing a highly effective seal . In contrast , pump packing is expected to leak very slightly in a controlled manner . This minimal leakage is necessary to cool and lubricate the packing ; without it , the packing can overheat and potentially burn .
Example of PTFE ( Polytetrafluoroethylene ) packings , such as Teadit 2006 style packing .
There are three primary types of packing seals typically used in wastewater applications to address these factors .
Graphite or carbon fiber packing
For general applications involving moderately abrasive media or chemical aggressiveness , graphite and carbon fiber packings — such as Teadit ’ s style 2200C and 2002 — are excellent choices . Known for their ability to withstand high temperatures and resist aggressive chemicals , these packings provide a long-lasting seal with exceptional performance . Both of these styles , for instance , are constructed with a diagonal braiding of high-purity , continuous filament carbon fiber yarn impregnated with graphite and a corrosion inhibitor . This combination gives it enhanced properties , including a very low coefficient of friction and excellent heat dissipation , enabling use without flush water . These materials are ideal for abrasive environments and help extend the service life of pumps and valves by reducing wear .
PTFE ( Polytetrafluoroethylene ) packings
For highly chemically aggressive wastewater applications , PTFE packings are ideal due to their excellent chemical resistance and low friction properties . Although not all PTFE packings are FDA-compliant , choosing FDA-compliant materials can support standardization across an entire plant , even as FDA standards are not typically required for wastewater systems . Teadit ’ s packing styles 2005 and 2006 , for example , offer versatile and efficient sealing solutions when aggressive media is not present . Style 2005 is particularly suited for lowshaft-speed equipment , such as valves , while style 2006 includes a break-in lubricant , making it suitable for highershaft-speed equipment , like pumps . The complex braiding method using filled ePTFE results in packing with uniform density , high flexibility , and smoothness . This leads to very low emission values and an extremely long service life for the packing . Due to the high suppleness , only a minimum of maintenance is required .
There are three main approaches to preventing leaks when working with abrasive materials in pump packing . 1 . For pumps that process abrasive or slurry-filled media , packing materials with highly resistant synthetic fibers , like those with synthetic fibers , phenolic , and similar packing styles , are recommended . While these durable materials resist abrasives well , they also have higher coefficients of friction than other options , like carbon / graphite packing , which can sometimes cause challenges with temperature management .
2 . In some wastewater applications , combining different packing materials may be necessary to balance performance and longevity . A dual packing system , for example , combines two types of packing : one designed to handle abrasive materials and another with lower friction and higher heat dissipation . For example , a dual packing system could consist of the first two packing rings ( closer to the impeller ) being a synthetic fiber packing style , highly resistant to abrasion . The subsequent packing rings could then be graphite and PTFE to minimize energy consumption and ensure smooth operation . π www . valve-world . net Valve World November 2024
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