| 摘要 |
PURPOSE:To make the thickness of coating uniform by a method wherein valve plugs are pinched by split molds, which have a resin pouring port and an gas discharging port and make a uniform gap between the outside surface of the main body of any one of pipe joints and the inside surfaces of the molds, and finally two-part reaction type resin is forced in the gap. CONSTITUTION:A pref-formed polyacetal resin packing 2 is fitted to the rotary part of a cock and rubber rings 3 are fitted to both the ends of the cock as the airtight sealing means under the condition that the cock 1 is pinched horizontally from both sides by molds. After that, the molds and the cocks 1 as a body to be coated are heated up to 80+ or -5 deg.C. Under the above-mentioned condition, pressurized polyurethane- based two-part reaction type resin liquid mixed with coal tar is forced from a resin pouring port, which is provided on the lower part of the matching surfaces of the molds, in a cavity so as to fill the cavity with the resin liquid by displacing the air in the cavity in about 20 seconds. After being held at 50 deg.C for 3 hours in order to complete the cure reaction of the resin liquid, the molds are dismantled. The projections of resin cured in the resin pouring port and in a gas discharging port of the mold and cut off, resulting in leaving the resin pouring port mark 4 and the gas discharging port mark 3 on the cock as cooling marks. |
