Cooling tank for rails

Abstract

A cooling tank for the thermal treatment of a rail head provided with a structure comprising a first volume (2), adapted to be filled with a cooling fluid; a second volume (4), arranged above the first volume and communicating therewith, so that the fluid passes from the first to the second volume and the rail head to be thermally treated can be immersed therein; a partition plate (5) between first and second volume, provided with a single row of holes (6), preferably arranged at the center of the width of the second volume, for generating jets of cooling fluid from the first to the second volume; a pair of longitudinal bulkheads (7), arranged in said second volume perpendicular to the plate and symmetrically with respect to the single row of holes, adapted to direct the jets of fluid exiting from the holes vertically upwards.

Claims

1. A cooling tank, defining a longitudinal axis, for a thermal treatment of a rail head by immersion, comprising a volume adapted to be filled with a cooling fluid in which the rail head to be thermally treated can be immersed, said volume having a bottom, wherein the bottom is provided with only one single row of nozzles, arranged along said longitudinal axis and parallel to a symmetry plane of said volume, whereby jets of cooling fluid can be generated in said volume, wherein there is provided at least one pair of substantially reciprocally parallel longitudinal bulkheads, arranged in said volume substantially perpendicular to said bottom and symmetrically with respect to said single row of nozzles, configured to direct upwards and towards a center of the rail head said jets of cooling fluid, wherein adjustment means are provided in order to adjust a position of the longitudinal bulkheads in a vertical direction and/or to adjust a distance L between the two longitudinal bulkheads of said at least one pair, and wherein said, adjustment means for adjusting the position of the longitudinal bulkheads in a vertical direction comprise a plurality of flat support elements, each flat support element being arranged orthogonal to the longitudinal bulkheads and provided with two slits having a shape complementary to a shape of at least a part of a transversal section of the longitudinal bulkheads; and said longitudinal bulkheads are inserted in said slits of the flat support elements.

2. A cooling tank according to claim 1, wherein the longitudinal bulkheads and the single row of nozzles extend along the entire longitudinal extension of the tank.

3. A cooling tank according to claim 1, wherein the longitudinal bulkheads rest on the bottom.

4. A cooling tank according to claim 1, wherein the longitudinal bulkheads are distanced from the bottom.

5. A cooling tank according to claim 1, wherein a distance L between the longitudinal bulkheads is comprised in a range dL2d, where d is a diameter of the nozzles.

6. A cool tank according to claim 4, wherein a distance G between the longitudinal bulkheads and the bottom is comprised in a range 0<G1.5L, where L is a distance between the longitudinal bulkheads.

7. A cooling tank according to claim 1, wherein a height H of the longitudinal bulkheads is equal to H2L, where L is a distance between the longitudinal bulkheads.

8. A cooling tank according to claim 7, wherein the height H of the longitudinal bulkheads is equal to four or five times the distance L between the longitudinal bulkheads.

9. A cooling tank according to claim 1, comprising two or more longitudinal modules connected in succession to each other at ends thereof so as to define said volume.

10. A cooling tank according to claim 1, comprising a further volume, arranged under the volume and communicating therewith by means of said single row of nozzles.

11. A cooling tank according to claim 10, wherein there are provided one or more delivery manifolds, for an introduction of the cooling fluid into said further volume, provided with a bifurcation with two longitudinal stretches parallel to said symmetry plane, whereby the cooling fluid introduced into said further volume passes through the single row of nozzles into the volume.

12. A cooling tank according to claim 4, wherein lower ends of said bulkheads are chamfered or comprise an end stretch bent outwards, inclined by an angle other than zero with respect to a bulkhead body and to the symmetry plane of the volume.

13. A cooling tank according to claim 1, wherein the longitudinal bulkheads have a rectangular transversal section and a closed inner end of the slits is obtained at a distance equal to a distance G from a first base surface of the flat support elements, and wherein an open outer end of the slits is provided at a same height as one or more second base surfaces of the flat support elements, parallel to said first base surface.

14. A cooling tank according to claim 1, wherein the longitudinal bulkheads have a body having a rectangular transversal section and an end stretch bent outwards with respect to said body, inclined by an angle other than zero with respect to said body and to the symmetry plane of the volume, and wherein the longitudinal bulkheads are provided with a plurality of slits, obtained at the two slits provided in each of the flat support elements.

15. A cooling tank according to claim 14, wherein a closed inner end of the slits is made at a first distance from a first base surface of the support elements, and a first end of the longitudinal bulkheads, totally inserted into the slits, is at a second distance, shorter than said first distance, from the first base surface.

16. A cooling tank according to claim 13, wherein said distance is comprised in the range 0<G1.5L, where L is the distance between the longitudinal bulkheads.

17. A cooling tank according to claim 15, wherein said second distance is comprised in the range 0<G1.5L, where L is the distance between the longitudinal bulkheads.

18. A cooling tank according to claim 6, wherein lower ends of said longitudinal bulkheads are chamfered or comprise an end stretch bent outwards, inclined by an angle other than zero with respect to a bulkhead body and to the symmetry plane of the volume.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the invention will appear more clearly from the detailed description of preferred but non exclusive embodiments of a cooling tank, illustrated by way of a non-limiting example with the aid of the accompanying drawing tables, wherein:

(2) FIG. 1 shows a perspective view of a module of the cooling tank according to the invention;

(3) FIG. 2a shows a schematic section view of a first embodiment of the tank according to the invention;

(4) FIG. 2b shows a schematic section view of a second embodiment of the tank according to the invention;

(5) FIG. 3a shows the rate vectors of the cooling fluid, at operating speed, in the case of a tank without bulkheads;

(6) FIG. 3b shows the rate vectors of the cooling fluid, at operating speed, in the case of the tank of FIG. 2a;

(7) FIG. 3c shows the rate vectors of the cooling fluid, at operating speed, in the case of the tank of FIG. 2b;

(8) FIG. 4a shows a schematic section view of a variant of the tank of FIG. 2a;

(9) FIG. 4b shows a schematic section view of a variant of the tank of FIG. 2b;

(10) FIG. 5a shows a perspective view of some components of the tank according to the invention in a first operating position;

(11) FIG. 5b shows a perspective view of some components of the tank according to the invention in a second operating position;

(12) FIG. 6 shows an exploded view of the components of FIG. 5b;

(13) FIG. 7 shows a front view of the components of FIG. 6.

(14) The same reference numerals in the figures identify the same elements or components.

DETAILED DESCRIPTION OF THE INVENTION

(15) With reference to FIGS. 1 and 2, there is shown a preferred embodiment of a cooling tank for the thermal treatment of the rail head, object of the present invention.

(16) The tank is provided with a structure comprising: a lower volume 2, adapted to be filled with a cooling fluid; an upper volume 4, arranged above said lower volume 2 and communicating therewith so that the cooling fluid can move from the lower volume 2 to the upper volume 4, said upper volume 4 having a vertical symmetry plane and having the upper end open for immersing the rail head to be thermally treated; a partition plate between lower volume 2 and upper volume 4, defining the bottom 5 of the volume 4, provided with a single row of holes or nozzles 6 which generate vertical jets of cooling fluid, directed upwards, from the lower volume to the upper one; a pair of longitudinal bulkheads 7, arranged in the upper volume 4 perpendicular to the partition plate and symmetrically with respect to said single row of nozzles 6, adapted to direct the jets of cooling fluid exiting the nozzles 6.

(17) Preferably but not necessarily the longitudinal axis X, wherealong holes 6 are arranged, lies on the symmetry plane of the upper volume 4 of the tank.

(18) Advantageously, the longitudinal bulkheads 7 and the single row of nozzles 6 extend along the entire longitudinal extension or length of the tank.

(19) In order to obtain an optimal cooling, rail 10 to be treated is at least partly immersed with the head 10 thereof into the upper volume 4, arranging the rail 10 with its symmetry plane arranged vertically and coincident with the symmetry plane. In this way, the jets of cooling fluid, directed centrally with respect to the tank width, are also directed towards the center of the rail head so that there is treatment symmetry.

(20) The lower volume 2 is the so-called delivery volume whereas the upper volume 4 is the so-called cooling volume where the thermal treatments of the rail are carried out. The two volumes 2 and 4 are put in communication through the holes 6, all having a same diameter d, wherethrough the cooling fluid is pushed from the lower volume to the upper one. The axis of holes or nozzles 6 is perpendicular to the partition plate and parallel to bulkheads 7.

(21) Advantageously, the diameter d of holes 6 is about 6-12 mm, preferably equal to 10 mm, whereas the pitch between the holes is about 1.5-5 times the diameter of the holes, preferably 3 times the diameter of the holes.

(22) The partition plate, defining the bottom 5 of the volume 4, is arranged perpendicular to the side walls of the tank. The lower volume 2 and the upper volume 4 preferably have the same width B and a reciprocally different height (AC in FIGS. 2a and 2b). However, an alternative variant may provide for a same height for both volumes 2, 4.

(23) With reference to FIGS. 2a and 2b, the distance L between the two bulkheads 7 preferably has a minimum value equal to diameter d of the holes and, in order not to lose the positive effect of the presence of the bulkheads and therefore not to reduce the rate of the jet of fluid exiting holes 6, a maximum value equal to twice the diameter of holes 6. Preferably, the distance L is larger than the diameter d of holes 6 by about 4-6 mm.

(24) Thickness s of the bulkheads 7, preferably (but not necessarily) made of a metal material, advantageously is as small as possible inasmuch it is possible to ensure an adequate sturdiness and stiffness of the bulkheads, for example equal to about 5 mm.

(25) Height H of the bulkheads 7 cannot be too short as it must allow the jet of fluid to be channeled by a sufficiently long path so that it reaches the rail head to be treated without flitting. Preferably, height H is not shorter than twice distance L between the bulkheads (H2L); even more preferably, it is equal to four-five times distance L between the bulkheads.

(26) In a first advantageous variant of the tank of the invention, illustrated in FIG. 2a, the longitudinal bulkheads 7 rest on the partition plate 5, for example welded to said plate by the entire longitudinal extension or length thereof.

(27) On the other hand, in a second, even more advantageous variant of the tank of the invention, shown in FIG. 2b, a distance or gap G is provided between the lower end of the bulkheads 7 and the bottom of the upper volume 4 consisting of the partition plate 5. Such gap G cannot be too large since, if the jet of cooling liquid was not restrained, it would proceed enlarging with respect to the axis of holes 6 and would hit against the lower part of the bulkheads 7, drastically losing speed and risking not to be channeled into the longitudinal slit or channel 9 defined by the reciprocally parallel bulkheads 7.

(28) Advantageously, the distance or gap G is comprised in the range 0G1.5 L. If a distance G other than zero is provided between the lower end of the bulkheads 7 and the partition plate 5, the lower ends of said bulkheads are advantageously chamfered so as to facilitate the conveying of the jet of cooling fluid in the longitudinal slit 9. An alternative variant (not shown) provides that the lower ends of the longitudinal bulkheads 7 comprise an end stretch 7 bent outwards (see bulkheads 7 in FIG. 7), inclined by an angle other than zero with respect to body 7 of the bulkhead and to the symmetry plane of the volume 4. Preferably, the inclination angle of the end stretches 7 is less than 10, preferably comprised in the range between 1 and 8. Such end stretch 7 may have a height equal to about 1/3H1/4H . This variant is particularly useful if the distance between the bulkheads 7 and the partition plate 5 is significant, as it allows the fluid flow exiting nozzles 6 to be prevented from hitting the lower end of bulkheads 7 and allows the fluid flow to be received and centrally conveyed into the longitudinal slit 9.

(29) A further embodiment of the cooling tank of the invention provides for adjustment means for adjusting the bulkhead position (either manual or automatic), for adjusting the distance L between the two bulkheads and/or the gap G from the bottom of the tank when provided, so as to change the cooling rate without modifying the cooling fluid flow rate.

(30) In a preferred embodiment, such adjustment means comprise a plurality of support elements 11, in jargon referred to as supporting legs.

(31) In a first variant, illustrated in FIG. 4a or 4b, each substantially flat support element 11 is provided with two slits or notches 12 having a shape complementary to the shape of the rectangular transversal section of the two longitudinal bulkheads 7. The two bulkheads 7 are therefore entirely inserted into slits 12 of the plurality of support elements 11 and are integrally fixed to said support elements 11, for example by welding.

(32) Advantageously, the dimensions of the support elements 11 and of the slits 12 are designed so as to allow the bulkheads 7 to be positioned at two predetermined distances from the bottom of the volume 4. The related figures show an example wherein the two predetermined distances whereat bulkheads 7 may be positioned with respect to the bottom of the volume 4 are G and 0 (zero). The closed inner end 13 of the slits 12 is made at a distance equal to the distance G from a first base surface 14 of the support elements 11. In this way, a first end of the bulkheads 7 is at distance G from the first base surface 14. The open outer end 16 of the slits 12, on the other hand, is provided at the same height as one or more second base surfaces 15 of the support elements 11, parallel to the first base surface 14. In this way, making slit 12 with a height shorter than or equal to the height H of the bulkheads 7, a second end of the bulkheads 7 is at the most at a null distance from the second base surface(s) 15.

(33) A second variant, not shown, may provide for making slit 12 with a higher height than height H of the bulkheads 7, in any case keeping the same height as elements 11 as in FIG. 4; in this way, when the bulkhead is totally inserted in the respective slit, the second end of the bulkheads 7 is at a distance G (advantageously shorter than G) from the second base surfaces 15. In this latter variant, the support elements 11 are made so that both the two positions thereof, indicated in the Figures, allow the bulkheads to be arranged at a gap other than zero from the partition plate 5 or bottom of the tank. In this case, along the longitudinal axis X, both longitudinal ends of the bulkheads 7, having respective central longitudinal bodies reciprocally parallel and each defining a plane perpendicular to the partition plate 5, may optionally be inclined outwards by an angle other than zero with respect to the bulkhead body and to the symmetry plane of the volume 4. Preferably, the inclination angle of the lower and upper end stretches is less than 10, preferably in the range between 1 and 8. The sum of the heights of such lower and upper end stretches may for example be equal to about 1/3H1/4H, where H is the bulkhead height. Advantageously, the bulkheads 7 are provided with a plurality of slits or notches (such as for example the slits 16 shown in FIG. 6), made at the connection points of the bulkheads 7 with the support elements 11, i.e. at the two slits or notches 12 provided in each one of the support elements 11. The slits on the bulkheads are made along the entire height of the lower and upper end stretches and optionally also in a part of the body of the bulkhead 7 defining a plane perpendicular to the partition plate 5.

(34) In a third variant, shown in FIG. 5a o 5b-7, each substantially flat support element 11 is provided with two slits or notches 12 having a shape complementary to a part of the transversal section of the two longitudinal bulkheads 7. The longitudinal bulkheads 7, reciprocally parallel and each defining a plane perpendicular to the partition plate 5, comprise at least one end stretch 7 bent outwards, inclined by an angle other than zero with respect to the bulkhead body 7, defining said perpendicular plane, and to the symmetry plane of the volume 4. Preferably, the inclination angle of the end stretches 7 is less than 10, preferably in the range between 1 and 8. Such end stretch 7 may have a height equal to about 1/3H1/4H.

(35) Advantageously, the bulkheads 7 are provided with a plurality of slits or notches 16 made at the connection points of the bulkheads 7 with the support elements 11, i.e. at the two slits or notches 12 provided in each one of the support elements 11. Slits 16 are made along the entire height of the end stretches 7 and optionally also in a part of the body 7 of the bulkhead 7 defining a plane perpendicular to the partition plate 5. The two bulkheads 7 are inserted in slits 12 of the plurality of the support elements 11 and are integrally fixed to said support elements 11, for example by welding. The dimensions of the support elements 11 and of the slits 12 are designed so as to allow the bulkheads 7 to be positioned at two predetermined distances from the bottom of the volume 4. The closed inner end 13 (FIG. 7) of the slits 12 is made at a distance equal to a distance J>G from a first base surface 14 of the support elements 11. A first end of the bulkheads 7, in particular the end stretch 7, when they are totally inserted into slits 12, is at distance G from the first base surface 14. On the other hand, the open outer end 16 of the slits 12 is provided at the same height as one or more second base surfaces 15 of the support elements 11, parallel to the first base surface 14. A second end of the bulkheads 7, when totally inserted into slits 12, is at a null distance from the second base surface(s) 15.

(36) In the variants described above, the support elements 11 are arranged reciprocally parallel and orthogonal to the symmetry plane of the volume 4, and are regularly positioned along the bulkheads 7 and, thus, along the volume 4 of the tank. The distance between one support element and the next one is for example equal to about 500 mm. By arranging the support elements 11 and the bulkheads 7, welded thereto, with the second base surfaces 15 resting on the partition plate 5, i.e. on the bottom of volume 4, as shown in FIG. 4a or 5a, the longitudinal bulkheads 7 rest on the partition plate 5. On the other hand, by arranging the support elements 11 and the bulkheads 7, welded thereto, with the first base surface 14 resting on the partition plate 5, i.e. on the bottom of the volume 4, as shown in FIG. 4b or 5b, the longitudinal bulkheads 7 are positioned at a distance or gap G from the bottom of the upper volume 4 consisting of the partition plate 5. In order to switch from the position of FIG. 4a or 5a to the position of FIG. 4b or 5b it is simply possible to rotate the monolithic group, consisting of the bulkheads 7 and of the support elements 11, by 180.

(37) On the side of the upper volume 4 of the cooling tank there are provided respective side volumes (not shown) where the cooling fluid overflowing from the top of said upper volume 4 is collected. The two side volumes are provided with discharge tubes along the extension thereof. The cooling fluid already used for the thermal treatment of the rail flows, through the discharge tubes, into a recirculation circuit of the cooling fluid.

(38) The cooling tank may advantageously consist of a plurality of longitudinal modules 1, reciprocally connected by flanges or other suitable connecting means so as to form a single element. The longitudinal extension and the number of such modules 1 are such as to define a total length of the cooling tank longer than the length of the rail to be thermally treated by immersion of the head into said tank. A variant is provided with sliding blocks for sliding the modules in a longitudinal direction for allowing any thermal expansion of the tank. Only the central module or modules are fixed without possibility of movement.

(39) Advantageously, modules 1 may be fed through a cooling fluid delivery circuit which is provided with symmetric branches, in a number equal to a power of two, and thus a uniform distribution of the rate among the modules.

(40) Each module 1 is provided with a fluid inlet conduit arranged laterally and centrally with respect to the longitudinal extension of the same module. Such inlet conduit is connected to a delivery manifold 3 provided in the lower volume 2 of each module 1. Such delivery manifold 3, downstream of a first stretch defining an axis perpendicular to the longitudinal axis of the tank, is provided with a bifurcation with two longitudinal stretches 3 parallel to the symmetry plane of the upper volume of the tank. The two longitudinal stretches 3 may be positioned exactly below the vertical of the holes 6 or staggered with respect to the row of holes 6 by a distance equal, for example, to the conduit diameter.

(41) Inlet conduit and delivery manifold 3 may be made as a single piece. The delivery manifold 3, comprising the two longitudinal stretches 3, is positioned in the lower part of the lower volume 2 of the tank.

(42) By suitably selecting the section of the delivery manifold 3 and of the respective longitudinal stretches 3 as well as the number and dimensions of the holes 6, a substantially equal distribution of the rates exiting said holes is obtained on the entire longitudinal development of the tank, allowing a flow uniformity and, thus, a thermal treatment uniformity.

(43) The cooling fluid continuously enters the delivery manifold 3, and thus the two longitudinal stretches 3, at a predetermined first pressure and exits at a predetermined second pressure, at least equal to the piezometric load exerted by the hydraulic head of the overlying fluid, through the plurality of the calibrated holes 6, in the lower part of the upper volume 4. Then, passing through the longitudinal slit or channel 9 defined by bulkheads 7, the fluid proceeds aligned and with no flitting along a vertical direction towards the piece to be treated, to then continue on the sides of the same, cooling them.

(44) A continuous, on the average uniform upward flow is obtained with the structure of the tank of the invention, which laps the immersed rail head at a relative fluid-head surface rate such as to ensure a constant thermal exchange and thus make the thermal treatment of the same head uniform on the entire rail length.