Abstract Molten, thermoplastic resin is extruded from an annular die having a central hole through which an elongated article, such as a pipe is moved axially, so as to cost the article with hot resin. The hot resin coating is then precooled by a uniform stream of air issuing from an annular slot in a ring surrounding the coated article. The slot is inclined in the direction of axial movement of the article. The article then enters a similar ring also having a second inclined slot for discharging a uniform stream of cooling water onto the coated article. The direction and force of the stream of air deflects the sprayed stream of water so that it contacts the coated article in a substantial axial direction so that the contact line of the water spray is substantially tangential to the surface of the elongated article. Thereafter, the article enters through a gasketed opening in its side wall, of a tank containing a liquid to effect cooling of the coated article by immersion. The coating is free of defects due to prior deflection of cooling water preventing direct impingement and providing substantially tangential contact zones of the water on the article.
Apparatus according to claim 1 wherein, said cooling air blowing means is a ring with an annular nozzle directed along the axis of movement of the coated articles at an angle of 0 to 30* thereto and is conical in shape.
Claim 2
Dependent Claim
42 words
Apparatus according to claim 1 wherein, said water cooling means is a ring that has an annular nozzle directed in the axis of movement of the coated articles at an angle of 30* to 60* thereto, and is also conical in shape.
Claim 3
Independent Claim
130 words
The method for coating elongated articles with thermoplastic resins which comprises coating the outer surface of said articles with molten thermoplastic resin and solidifying the resin coat by cooling with cooling air from a cooling air blowing ring blown along the surface of the coated articles to pre-cool the same, and then with cooling water from a water cooling ring said air being blown along the surface of the article toward the cooling water so that the cooling water is prevented from directly impinging on the coated articles, and the contact line of the cooling water on the coated articles is thereby maintained substantially tangent with respect to the surface of the elongated coated articles along its major axis and subsequently introducing said articles into a bath of cooling water.
Claim 4
Dependent Claim
196 words
Method of coating an elongated article with thermoplastic resin according to claim 4, which comprises, extruding molten resin through an annular die surrounding the article to form a coating thereon, moving the coated article axially in the direction of its length through a hole in the axial center of the die, while such resin is so extruded, to coat the article, blowing cool air, from an annular slot in a first ring surrounding such coating, in a direction substantially parallel to the direction of movement onto the moving surface of the resulting coating on the moving article, said slot being inclined in the direction of movement of said coated article and then spraying cooling water from a second annular slot in a second ring surrounding said coated article positioned downstream with respect to said first ring, such second slot being also inclined in the direction of movement of the coating whereby the air blown from said first ring deflects the water from said second ring in a direction tangential to said coating moving surface to prevent direct impingement of said water upon said coated surface and subsequently introducing said article into a bath of cooling water.
Claim 5
Dependent Claim
37 words
The invention as defined by claim 5, in which the coated article is subsequently introduced into a bath of cooling water by moving same through a gasket-sealed opening in the side wall of a cooling water tank.