Hose extrusion mandrel and method for manufacturing a hose
A hose extrusion mandrel for manufacturing rubber hoses includes: a solid thermoplastic, elongate core; and a rubber compound outer layer covering a surface of the elongate core. A ratio between a diameter of the core and a thickness of the rubber compound layer may be between 8 and 11.
1. A hose extrusion mandrel for manufacturing rubber hoses, comprising:
a solid thermoplastic, elongate core having a diameter of at least 24 millimeters; and
a rubber compound outer layer covering a surface of the elongate core,
wherein the outer layer directly contacts the surface of the elongate core, and
wherein a ratio between a diameter of the core and a thickness of the rubber compound layer is between 8 and 11.
2. The hose extrusion mandrel of claim 1 , wherein the solid thermoplastic, elongate core comprises polypropylene or polyamide.
3. The hose extrusion mandrel of claim 1 , wherein the rubber compound outer layer comprises ethylene propylene diene rubber (EPDM) or acrylonitrile butadiene rubber (NBR).
4. The hose extrusion mandrel of claim 1 , wherein an outer diameter of the elongate core and the outer layer combined is at least 31.4 millimeters.
5. A method for manufacturing rubber hoses, comprising:
providing an extruder having a die with a die opening;
providing the hose extrusion mandrel of claim 1 , which hose extrusion mandrel has an outer diameter smaller than the die opening;
extruding a rubber mass through the die opening; and
advancing the hose extrusion mandrel together with the extruded rubber mass through the die opening so that the hose extrusion mandrel is lined with a layer of the extruded rubber mass.
6. The method of claim 5 , further comprising:
braiding a reinforcement layer around the hose extrusion mandrel lined with the layer of the extruded rubber mass, downstream of the die opening; and
extruding a covering layer of rubber mass around the hose extrusion mandrel provided with the reinforcement layer to cover the reinforcement layer.
7. The method of claim 5 , wherein the hose extrusion mandrel is provided wound on a reel, and
wherein the hose extrusion mandrel is supplied to the die opening by unwinding the hose extrusion mandrel from the reel.
8. The method of claim 5 , further comprising:
after a length of hose is manufactured, cutting the rubber mass at the die; and
removing the hose extrusion mandrel from the manufactured length of hose.