A scenario sometimes seen with mechanical packing is where the packing in a pump or valve is run beyond its expected service life to the point of failure. This is usually done in an attempt to get the most out of the packing, thus avoiding the need to execute a change-out.
Operators and maintenance personnel can get a false sense security when mechanical packing is pushed beyond its recommended service life. Pumps and valves will often continue to operate normally until the packing fails. Then, the only recourse is to take the equipment offline and change the packing.
The problems with this approach are twofold. First, one can never be sure when the packing will fail. Murphy’s Law usually prevails – the packing will fail at the most inopportune time for it to do so, causing unwanted downtime and throughput losses. Secondly, as the packing deteriorates, operating costs increase. This occurs because worn packing increases equipment wear and tear through increased heat and friction, while additional maintenance labour must often be utilized to maintain an acceptable leak rate.
Signs of Mechanical Packing Failure
Failure of mechanical packing usually manifests itself in three ways:
Increased leakage rate
Uncontrolled leakage
Smoke and heat
Other symptoms of failed packing include packing extruding from the pump or valve body, hard and brittle packing discovered upon inspecting the pump or valve interior, or the failure to achieve baseline leakage rates with normal equipment adjustments. All of these symptoms are strong clues that the packing should be replaced.
Preventing Mechanical Packing Failure
The best policy for reducing packing failures is to replace the packing at frequent intervals. These intervals should be no longer than that recommended by the packing manufacturer for your operating conditions. Since the life cycle of a given packing is highly depended upon the specific conditions in which it is operating, manufacturers’ service life recommendations may need to be shortened according to the specific equipment and application in which the packing is used. Always consult the packing supplier for specific guidance.
For optimal service life and performance, always procure packing from a reputable supplier such as Canada Rubber Group Inc. (CRGI). At CRGI, we stock and supply a wide variety of mechanical packing manufactured by Teadit. These high quality packings support a wide range of applications and service conditions, providing users with unmatched reliability and performance.
To find out more about the mechanical packing that CRGI can supply, please contact our sales department directly at crg@canadarubbergroup.com.