Distributor tube for cooling metal strips
The invention refers to a distributor tube ( 400 ) for cooling metal or similar products, in particular steel strips, comprising along the longitudinal extension of said distributor tube ( 400 ), a plurality of outlet openings ( 406 ) through which a cooling fluid can be ejected; an inlet ( 402 ) and a closure ( 404 ) of said tube at its ends; a connection for connecting a source of cooling fluid and feeding said distributor tube ( 400 ) with said fluid. At least on the inlet side ( 402 ) there is a zone of change in the diameter of the tube, which varies from a sector with a smaller diameter, followed in the direction of flow by a sector with a larger diameter. Upstream of said plurality of outlet openings ( 406 ) there is an orifice ( 414 ) in the area of the flow section. Further described are a corresponding hot-rolling plant and a use of the distributor tube.
1. A distributor tube for cooling metal, leaving a hot-rolling mill comprising:
(a) along a longitudinal extension of said distributor tube, a plurality of outlet openings through which a cooling fluid can be ejected;
(b) an inlet located at one end of said distributor tube for said cooling fluid and a closure of said distributor tube at another end, and
(c) a connection for connecting a source of cooling fluid and feeding said distributor tube with said cooling fluid;
wherein at least on an inlet side of said distributor tube there is a zone of change in a diameter of the distributor tube, which varies from a sector with a smaller diameter, followed in a direction of flow by a sector with a larger diameter,
wherein upstream of said plurality of outlet openings there is an orifice in an area of a flow section,
wherein the orifice is a plate comprising a plurality of holes.
2. The distributor tube according to claim 1 , wherein the plurality of holes have a diameter in a range of 5 to 10 mm.
3. The distributor tube according to claim 2 , wherein the plurality of holes are arranged in a triangular pitch.
4. The distributor tube according to claim 3 , wherein the pitch between adjacent holes is between 7.5 and 15 mm.
5. The distributor tube according to claim 1 , wherein a ratio of a sum of surfaces of the plurality of holes of the orifice to an internal surface of the distributor tube in an area of larger diameter, is in a range from 30 to 40%.
6. The distributor tube according to claim 1 , wherein the plurality of outlet openings are arranged on a straight line.
7. The distributor tube according to claim 1 , wherein said orifice is located in said sector with larger diameter.
8. The distributor tube according to claim 1 , wherein a number of the plurality of outlet openings is in a range from 22 and 32 for a tube length in a range of from 1.5 to 2 m.
9. The distributor tube according to claim 1 , wherein the orifice is located at a distance of at least 10 cm from a nearest outlet opening.
10. A hot-rolling plant comprising in a cooling zone;
a roller conveyor for a transport of a product to be cooled, wherein at least one distributor tube according to anyone of the preceding claims is placed between rollers of the roller conveyor.
11. The hot-rolling plant of claim 10 , wherein the product to be cooled includes a strip having a width/thickness ratio ranging from 2000 to 75.
12. The distributor tube of claim 1 , wherein the metal comprises a steel strip.