Garry J Dodson

US Patent:

49346571, Jun 19, 1990

Filed:

Mar 10, 1986

Appl. No.:

6/837791

Inventors:

Garry W. Dodson - Pelham AL

International Classification:

F16J 1520
F16J 1524
F16K 4102

US Classification:

251214

Abstract:

A helical spacer, e. g. made of stiffly flexible nylon and having flat axially-presented surfaces, in slid onto a cylindrical mandrel, e. g. a die inside body. Flexible corrugated ribbon of expanded graphite is helically wound onto the mandrel between turns of the spacer. This assembly is placed in a tubular die outside body and tubular punches are run into the die outside body, and moved axially towards one another telescopically of the mandrel. The punches, engaging opposite turns at ends of spacer axially compress and radially expand the helix of graphite, raising its density and producing a product which, in transverse cross-section, closely resembles conventional pre-formed stuffing box packing rings made of the same ribbon starting material. The helical graphite packing stock is disassembled from the spacer and mandrel by rotation, and supplied to the trade. In use, some of the stock is telescoped onto a valve stem, or a mandrel of the same diameter as the valve stem, and cut to length, e. g.