Abstract: An automatic center cavity equalizing valve for equalizing pressure in a main valve. The equalizing valve includes a body with a bore for providing fluid communication between an upstream port and a center cavity port, and a downstream port and the center cavity port. A metal ball is disposed within the bore and is arranged to mate with upstream and downstream seats to seal communication with the upstream or downstream port and the center cavity port depending upon the differential pressure across valve. The metal ball is spring biased against the downstream seat to prevent damage to the downstream seat due to rattling. In addition, access plugs are provided at opposite ends of the bore to allow for access to the interior of the bore for repairing or replacing the metal ball, the seats, and/or other internal components.

Abstract: A valve is presented comprising a valve body defining a chamber, a valve stem extending into said chamber, a disk attached to the valve stem, a discrete annular seat movably disposed in the chamber, a resilient ring disposed in the chamber adjacent the annular seat, and a retainer fixed in the chamber on a side of the seat opposite from the ring, wherein the ring exercises a bias on the seat in a direction toward the disk, urging the seat into engagement with the disk. The invention further contemplates a method for making the valve.

Abstract: This is a unitary all-plastic ball valve particularly for use with natural gas distribution lines which are plastic and buried in the earth, where the parts are designed to assure accurate assembly in order to provide a unitary sealed valve body impervious to most elements encountered, inside or outside the valve.

Abstract: An all-plastic valve having a unitary body has a cap assembly for excluding external contaminants from the interior of the valve while allowing venting of excess pressure from the interior.

Abstract: A method of assembling an all-plastic valve that assures proper positioning of the associated parts while forming a unitary, leaf-proof valve body.