0ed2c426_3____The_ClusterManager_object__Attribute
[Description] Frequency of the session expiration, and related manager operations. Manager operations will be done once for the specified amount of backgroundProcess calls (i.e., the lower the amount, the more often the checks will occur). The minimum value is 1, and the default value is 6. [Attribute] 
processExpiresFrequency
Apache Tomcat 7 Configuration Reference (7.0.63) - The ClusterManager object