Method and mold for making a pleated filter cartridge

A method for making a pleated filter cartridge using a mold that has an elastomeric surface for forming a seal with a bottom end of a pleated filter, the method comprising the steps of:

• placing the bottom end of the pleated filter on an elastomeric surface of the mold, the pleated filter having pleats that define an inner cavity and a perimeter, the elastomeric surface comprising a circular bump protruding from the elastomeric surface, the circular bump being disposed within the inner cavity and having a height that is at a maximum at the center of the circumference of the circular bump and diminishes in height from the center of the circumference to the perimeter of the circumference, the center of the circumference intersecting a central longitudinal axis of the pleated filter;
• applying a downward force to the top end of the pleated filter to cause the pleated filter to establish a seal with the elastomeric surface of the mold;
• adding a polymerizable potting compound to the inner cavity and permitting the potting compound to cover the portion of the elastomeric surface of the mold that is encompassed by the pleats including the spaces between the pleats that are part of the inner cavity, the circular bump being shaped to guide the potting compound toward the pleats, the potting compound being selected to form a polyurethane after polymerization, wherein the polymerizable potting compound does not extend outside the perimeter of the pleated filter;
• permitting the potting compound to polymerize to form a polyurethane bottom end cap;
• and
• removing the polyurethane bottom end cap from the mold.