Multi-layer pipe manufacturing apparatus and method of manufacturing multi-layer pipes using the same

Abstract

An apparatus for manufacturing a multi-layer pipe is provided. The apparatus includes a ram extruding a matrix pipe, which is formed by inserting one or more insert pipes having different diameters into a receiving pipe, with a constant compression force, a heat-treatment unit heat-treating the matrix pipe extruded from the ram, and a drawing unit drawing, with a constant drawing force, the matrix pipe passing through the heat-treatment unit into a multi-layer pipe having a predefined diameter.

1 . An apparatus for manufacturing a multi-layer pipe, the apparatus comprising:
 a ram extruding a matrix pipe, which is formed by inserting one or more insert pipes having different diameters into a receiving pipe, with a constant compression force;   a heat-treatment unit heat-treating the matrix pipe extruded from the ram; and   a drawing unit drawing, with a constant drawing force, the matrix pipe passing through the heat-treatment unit into a multi-layer pipe having a predefined diameter.   
     
     
         2 . The apparatus according to  claim 1 , wherein the constant compression force and the constant drawing force are identical or different. 
     
     
         3 . The apparatus according to  claim 1 , wherein an outer surface of an outermost insert pipe inserted into the receiving pipe comes into contact with an inner surface of the receiving pipe, and an outer surface of another insert pipe inserted into a former-inserted insert pipe inserted into the receiving pipe comes into contact with an inner surface of the former-inserted insert pipe. 
     
     
         4 . The apparatus according to  claim 1 , wherein the heat-treatment unit is a heat furnace accommodating the matrix pipe extruded from the ram, or a high-frequency induction heater arranged along a direction in which the matrix pipe extruded from the ram is formed. 
     
     
         5 . The apparatus according to  claim 4 , wherein the high-frequency induction heater includes:
 a single-frequency generator for high-frequency induction heating bonding of the receiving pipe and the insert pipes that are formed of the same material to constitute the matrix pipe; and   a multi-frequency generator for high-frequency induction heating bonding of the receiving pipe and the insert pipes, respectively, that are respectively formed of different materials to constitute the matrix pipe.   
     
     
         6 . The apparatus according to  claim 1 , wherein the drawing unit includes:
 a die having an extrusion hole section through which the multi-layer pipe is extruded from the ram into a smaller outer diameter relative to that of the matrix pipe;   a clamp clamping an end of the multi-layer pipe extruded from the die; and   a carrier carrying the multi-layer pipe with the constant drawing force along a direction of the multi-layer pipe being extruded, the clamp being provided to the carrier.   
     
     
         7 . The apparatus according to  claim 6 , wherein the extrusion hole section includes:
 a first end hole having a first diameter that is disposed on a first side of the die so as to face the ram;   a middle hole disposed in the die concentrically with the first end hole and having a second diameter smaller than the first diameter;   a second end hole disposed on a second side of the die opposite to the first side, concentrically with the middle hole and having the second diameter;   a first extrusion guide part connecting the first end hole and the middle hole and having a diameter decreasing towards the carrier; and   a second extrusion guide part connecting the middle hole and the second end hole and having a constant diameter towards the carrier,   wherein the first diameter corresponds to an outer diameter of the matrix pipe and the second diameter corresponds to an outer diameter of the multi-layer pipe.   
     
     
         8 . The apparatus according to  claim 6 , wherein the drawing unit further includes a mandrel extending from the carrier towards the ram separately from the clamp and disposed at the center of the clamp so as to, when inserted into the multi-layer pipe, maintain an inner diameter of the multi-layer pipe to be constant. 
     
     
         9 . The apparatus according to  claim 6 , wherein the clamp is provided with a plurality of chucks attached to the carrier and radially arranged so as to be separated from or to contact an outer surface of the multi-layer pipe. 
     
     
         10 . The apparatus according to  claim 1 , wherein the receiving pipe and the insert pipes are formed of the same material or different materials. 
     
     
         11 . The apparatus according to  claim 1 , wherein the receiving pipe and the insert pipes are any one of an electric resistance welding (ERW) pipe and a seamless pipe. 
     
     
         12 . The apparatus according to  claim 1 , wherein the insertion pipe is formed of one of stainless steel, aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, and a combination thereof. 
     
     
         13 . The apparatus according to  claim 1 , wherein the receiving pipe is formed of one of carbon steel, cobalt-base alloy steel, aluminum, aluminum alloy, brass, high manganese steel, and a combination thereof. 
     
     
         14 . The apparatus according to  claim 1 , wherein the receiving pipe or the insert pipe is provided, on an outer or inner surface thereof, with a plurality of reinforcing ribs spaced at regular intervals and linearly extending along a longitudinal direction of the receiving pipe or the insert pipe, the reinforcing ribs having alternating linear ridges and valleys. 
     
     
         15 . The apparatus according to  claim 1 , wherein the receiving pipe or the insert pipe is provided, on an outer or inner surface thereof, with a plurality of reinforcing ribs spaced at regular intervals and involutely extending along a longitudinal direction of the receiving pipe or the insert pipe, the reinforcing ribs having alternating involute ridges and valleys. 
     
     
         16 . The apparatus according to  claim 1 , further comprising a rotary actuator provided in one or both of the ram and the drawing unit and driven to rotate the extruded matrix pipe or the drawn multi-layer pipe in one direction. 
     
     
         17 . The apparatus according to  claim 6 , wherein the extrusion guide parts are provided with a duplex physical vapor deposition (PVD) coating layer or a diamond-like-carbon (DLC) coating layer. 
     
     
         18 . The apparatus according to  claim 8 , wherein the mandrel is provided, on an outer surface thereof, with a duplex physical vapor deposition (PVD) coating layer or a diamond-like-carbon (DLC) coating layer. 
     
     
         19 . A method of manufacturing a multi-layer pipe using an apparatus for manufacturing a multi-layer pipe, the method comprising:
 a first stage of forming a matrix pipe by inserting one or more insert pipes having different diameters into a receiving pipe;   a second stage of introducing the matrix pipe into a ram to extrude the matrix pipe with a constant compression or extrusion force;   a third stage of introducing the matrix pipe extruded from the ram into a heat-treatment unit to heat-treat the matrix pipe; and   a fourth stage of clamping an end of the matrix pipe heat-treated by the heat treatment unit and drawing the matrix pipe with a constant drawing force to form a multi-layer pipe having a desired diameter, using a drawing unit.   
     
     
         20 . The method according to  claim 19 , wherein an outer surface of an outermost insert pipe inserted into the receiving pipe comes into contact with an inner surface of the receiving pipe, and an outer surface of another insert pipe inserted into a former-inserted insert pipe inserted into the receiving pipe comes into contact with an inner surface of the former-inserted insert pipe. 
     
     
         21 . The method according to  claim 19 , wherein in the third stage, the matrix pipe extruded by the ram is heat-treated at a temperature ranging from 150° C. to 1350° C. by a heat furnace accommodating the matrix pipe or a high-frequency induction heater arranged along a circumferential face of the matrix pipe.