EP0283869B1 - Device to expose to a gas stream objects with flat surfaces in a position which can be traversed - Google Patents

Description

The invention relates to a device for the flow application of flat material in an arrangement with flowable gaps of the type specified in the introduction of claim 1.

"Areal goods" are understood to mean, in particular, plates, laminated cores, ingots and sheets which are produced from metallic, but also from non-metallic materials, for example from ceramics.

These areal goods can either be arranged in stacks with clear spaces between them or in the form of rows, i.e. the two-dimensional goods are arranged vertically next to each other.

In addition, the term "flat goods" also includes layers of bars, profiles or narrow bars or stacks of baskets which are filled with bulk goods or small good parts.

It is therefore only essential that the goods to be treated form at least one horizontal position or can be positioned vertically with a small width dimension relative to the height and have spaces that can be flowed through.

For the heat treatment of flat goods which are arranged in stacks or rows in broad layers, systems are usually used in which a gas flow is conveyed through the stack or the row by means of a suitable flow drive. In order to suppress asymmetries in heat treatment with this type of flow application, in particular by leading the temperature on the inlet side of the flow compared to the temperature on the outlet side, such systems are usually equipped with reversible flow drives, i.e. drives with reversible flow direction, or with complicated flap controls for Reverse flow direction.

However, such "reversing flaps" are particularly problematic when they have to be used in larger heat treatment systems with higher temperatures. In these cases, the reversing flaps can warp and jam, which leads to frequent malfunctions or even business interruptions.

As a practicable reversible flow drive, there is only one axial fan with appropriately selected blading available, in which a reversal of the conveying direction of the gas flow can be achieved by changing the direction of rotation of the impeller. With such axial fans, however, only relatively low pressures can be achieved since their peripheral speed is only limited for reasons of strength, in particular at high temperatures. This is why axial fans are only suitable for flow circuits with relatively low resistances, while with higher resistances, such as those that occur especially with a wide stack of flat good layers or high good rows compared to the width of the gaps, the achievable pressure figures for an effective flow are much are too low.

Another disadvantage of axial fans is that they usually have to be installed in a wall in high-temperature systems for storage reasons. This asymmetrical installation results in different outputs for the two directions of rotation of the fan wheel despite its corresponding adaptation and design. The differences in the heat transfer due to this can in principle be compensated for by a correspondingly longer treatment time of the goods. However, these longer treatment times lead to increased operating and thus manufacturing costs, so that the aim is generally to shorten the treatment times.

The invention is therefore based on the object of providing a device for the flow application of flat material of the type specified, in which the disadvantages mentioned above do not occur.

In particular, a device is to be proposed that ensures the uniform flow of the material in a structurally simple manner.

This is achieved according to the invention by the features specified in claim 1.

Expedient embodiments are defined by the features of the subclaims.

The advantages achieved with the invention are based on the fact that the reversing effect required for uniform flow application of the stack of a flat material or the series of flat material elements is achieved by a suitable design of the flow drive and flow guidance. Because with the blow-out channels or nozzles arranged offset on both sides of the stack of goods or the series of goods, the material is acted upon via relatively narrow zones with different flow directions, that is to say in counterflow. In this way, the same effect results as in a reversing system, without the flow direction having to be reversed. This effect can be reinforced by moving the stack of goods back and forth during the blowing in the longitudinal direction, that is to say perpendicular to the blowing devices. Since the stack of goods in the same direction in the If the device is introduced, the charging device, which is usually present anyway, is suitable, at most with a small modification.

By eliminating the need for a flow reversal, the use of radial fans is possible, as a result of which the disadvantages explained above associated with axial fans can be avoided.

The "universal blow chamber" constructed in this way can be operated with particularly high gas capacity flows because of its favorable flow design, which means that a uniform temperature can be achieved in the material to be heated, for example in heat treatment systems; moreover, the residence time of the goods can be shortened and the efficiency of the entire system can be increased, so that overall the operating costs are reduced. And finally, the inner housing can be constructed in a simple manner from many identical parts, so that a particularly cost-effective production is possible.

• Fig. 1 einen Querschnitt durch eine Vorrichtung zur Beaufschlagung eines Stapels eines flächenhaften Gutes mit einer Gas-Strömung,
• Fig. 2 einen Horizontalschnitt durch die Vorrichtung nach Figur 1 entlang der in Figur 1 eingetragenen Schnittebene B-B
• Fig. 3 einen Vertikalschnitt durch einen Ausblaskanal nach Figur 1 in vergrößertem Maßstab
• Fig. 4 einen horizontalen Schnitt durch einen Ausblaskanal der Vorrichtung nach Figur 1 in vergrößertem Maßstab
• Fig. 5 einen Querschnitt einer Vorrichtung zur Strömungsbeaufschlagung von hochkant gestellten Barren,
• Fig. 6 einen Horizontalschnitt durch die Vorrichtung nach Figur 5 längs der in dieser Figur eingetragenen, an der Mittellinie horizontal versetzten Schnittlinie A-A,
• Fig. 7 einen Längsmittelschnitt durch die Vorrichtung nach Figur 5,
• Fig. 8 im vergrößerten Maßstab einen Querschnitt durch einen Strömungskanal der Vorrichtung nach Figur 5 mit aufgesetzten Düsenrohren,und
• Fig. 9 verschiedene Anordnungen von flächenhaften Gütern.
• Fig. 10 die schematische Darstellung einer Vorrichtung gemäß Figur 1 mit einer Einrichtung zum Hin- und Herbewegen des Gut-Stapels während der Beblasung.

The invention is explained in more detail below with the aid of an exemplary embodiment of a device for the flow application of a stack of goods and a device for the flow application of a series of goods with reference to the accompanying schematic drawings. Show it

• 1 shows a cross section through a device for applying a gas flow to a stack of a flat good,
• 2 shows a horizontal section through the device according to FIG. 1 along the section plane BB entered in FIG. 1
• 3 shows a vertical section through a blow-out duct according to FIG. 1 on an enlarged scale
• 4 shows a horizontal section through a blow-out duct of the device according to FIG. 1 on an enlarged scale
• 5 shows a cross section of a device for pressurizing the flow of upright bars,
• 6 shows a horizontal section through the device according to FIG. 5 along the section line AA entered in this figure and horizontally offset at the center line, FIG.
• 7 shows a longitudinal central section through the device according to FIG. 5,
• Fig. 8 on an enlarged scale a cross section through a flow channel of the device of Figure 5 with nozzle pipes attached, and
• Fig. 9 different arrangements of areal goods.
• 10 shows the schematic representation of a device according to FIG. 1 with a device for moving the stack of goods back and forth during the blowing.

With the device shown in FIGS. 1 and 2, indicated overall by reference numeral 10, four bars 12 arranged one above the other to form a stack in the case illustrated by way of example are to be formed by means of suitable spacers, e.g. simple square profiles, kept at a distance of 13, are acted upon by a gas flow for the purpose of heat treatment.

A radial fan 14 is arranged vertically above the stack of bars 12 and conveys its volume flow into a housing 16 which blows out on two sides. From this housing 16, which opens into a collecting channel or box 17 on each blow-out side, blow-out channels 18 are supplied which are offset from one another on the two sides of the stack from the bars 12. In the embodiment shown, two blow-out channels 18 are provided on each side of the stack of goods, the other half of the housing 16 with the blow-out channels 18 being arranged in a rotationally symmetrical manner as shown in FIG. 2.

Between the two blow-out channels 18 there are return flow spaces 20 which are spatially arranged in such a way that each return flow space 20 has a blow-out channel 18 in the center on the other side of the stack of goods 12. The treatment gas, which has passed through the intermediate spaces between the layers of the material stack 12 (see FIG. 1, where the direction of flow is indicated by the arrows), is discharged out of the treatment chamber and fed into the suction chamber 22 of the radial fan 14 through the return flow chambers 20.

The blow-out ducts 18, which serve as inflow ducts, are dimensioned in such a way that a uniform inflow velocity is achieved over the entire duct length, that is to say over the entire height of the material stack 12. The deflecting grille 19 arranged in the blow-out cross section of the blow-out channels 18, which is shown enlarged in FIG. 3 and which causes the flow deflection in particular due to the underpressure arising on the outer surfaces of the cylindrical guide vanes 23 as a result of the Coanda effect, advantageously serves this purpose.

Depending on the nature of the material stack 12, it can be expedient if the blow-out channels 18 are provided with a strong side contraction, for example corresponding to a Borda inlet, as shown in FIG Flow direction suddenly tapered. This allows the expansion that would otherwise occur limit the emerging jet when inflating to the long sides of the goods, i.e. the bars 12.

As can be seen in particular from FIG. 2, the treatment gas flows downward from the radial fan 14 arranged vertically above the stack of goods 12, then through the outlet ducts into the spaces 13 between individual bars 12 of the stack and finally on the opposite side through the return flow spaces 20 back into the suction chamber 22 of the radial fan 14, so that, as is customary in systems of this type, a closed circuit results. Heating or cooling devices for the circulated gas stream can be arranged either in the collecting channels 17 or at the ends of the two-way ventilating fan housing 16 on the fan pressure side or in the suction chamber 22 on the fan suction side. Such devices are not shown in the figures since their embodiment is generally known.

In the description of an exemplary embodiment of a device for the flow application of a series, the application of the heat treatment of bars, e.g. B. in the light metal industry. FIG. 5 shows a cross section through such a device, in which case bars 32 placed on edge on a suitable support or transport construction, indicated by the I-profiles 40, form a good series and therefore appear in the figure in plan view as a rectangular area. The spatial arrangement of the bars 32 can be seen in particular from FIG. 7, in which the gaps 33 between the bars forming the good row 32 are also shown.

In the case of a device through which the bars 32 are pushed onto transport rails 40, that is to say a so-called "pushing furnace", the formation of the gaps is e.g. achieved in that the bars are placed in the middle of so-called shoes, designated 39 in Figures 5 and 7. The length of the closely fitting shoes, which are pushed through the furnace on the profiles 40 serving as rails, determines the division of the sequence and the gap width results from: division minus bar thickness. Since the transport movement always progresses by the same shoe length per pushing operation, the position of the gaps in the furnace always remains the same. Therefore, flow channels 35 a above and 35 b below the Gut-order can be arranged, on which nozzles 34 aligned with the gaps 33 are attached. In the example shown in FIGS. 5 to 8, a flow channel 35 supplies three rows of nozzles 34, each aligned with three adjacent gaps 33. Between the flow channels 35, large spaces are created due to the curved or cranked shape of the outer nozzle tubes 36 b. The nozzles 34 are arranged offset on the upper flow channel 35 a and the lower flow channel opposite this, so that the gaps in question are alternately partially flowed through from above and partly from below. In the case of a device with transport of the goods, as described above, it is advisable to move the nozzles additionally from pair of flow channels to pair of flow channels, because then in connection with the movement of the goods, a further change in loading serves to equalize. This arrangement is shown in FIG. 6 in the right half section for the two nozzle groups 35 aa and 35 from the two upper flow channels. However, it can also be expedient in devices with the described shock transport of the goods to select the flow direction in a gap in each case the same, but different from Lükke to gap. This is particularly advantageous if, with a flow direction changing within a gap, excessive flow mixing between opposite flows would occur with flow paths that are long relative to the gap width. Depending on the design of the device, a fan can be provided to supply only one pair of flow channels 35 a and 35 b or several pairs.

The backflow of the gas stream blown into the gaps 33 with the nozzles 34 takes place on the side of the product series 32 opposite the nozzles from the free spaces 38 a and 38 b. The gas flow partly mixes with the gas blown out of the neighboring nozzle groups due to the mixing tendency of free gas jets. As a result of this jet induction, a larger gas volume is set in motion than the fan promotes, which in turn promotes the uniformity of the action. To achieve free jets with the largest possible core length, as shown in FIG. 8, well-rounded mouthpieces 37 can be inserted into the ends of the nozzle tubes 36. In the embodiment of the device for the flow application of a good series, the gas flow takes place in a closed circuit, as shown with the schematic flow arrows in FIG. For the installation of fans, the arrangement of heating or cooling devices, the same basic considerations apply as for the previously described embodiment of the device for the flow loading of material stacks.

The main advantage of this device, namely the change in the flow direction in the free space between the good elements or good layers in relation to the dimensions of the Good small distances and, due to this, an equalization of the flow admission, become clear from both exemplary embodiments. Naturally, this also applies to other stacks of goods, for example layers of pipes, rods or profiles and other rows of goods, for example plates or boards held in racks or a barbed tape, so that there is a further area of application for such a device.

A further equalization of the flow loading can be achieved in that the flat material, in particular a stack of goods, is moved back and forth in an oscillating movement in the direction of its horizontal longitudinal axis during the blowing; the amplitude of this back and forth movement is adjusted so that it corresponds to the division of the blowing device, for example the blowing device 18 in the embodiment according to FIGS. 1 to 4.

For the same purpose, the intermediate layers or spacers or the transverse frame supports in the described embodiments should also be matched to the division of the blowing device in order to achieve a very homogeneous flow admission. In addition, the mutually directed gas flows in the interstices of the good locations can thereby be largely distinguished from one another, since mixing with the opposing neighboring flows is largely avoided; this in turn allows the flow velocity in the channel formed in this way, viewed in the direction of flow, to be maintained longer.

FIG. 9a shows two views of a stack of plates, ingots and sheets, the individual, horizontal layers being separated from one another by intermediate layers and thereby forming intermediate spaces, as can be seen in the illustration on the right.

FIG. 9b shows a stack of goods, in which the three upper layers are formed by bolts and rods and the lower layer by narrow bars. This position is held by mutually supported frames, which are shown in the right view of Figure 9b without the good.

FIG. 9c finally shows a plurality of horizontal layers formed by baskets which are stacked on top of one another; these baskets are filled with bulk goods or small parts.

The horizontal layers are also arranged so that there are gaps between the individual basket layers. These stacks can e.g. B. be built on a charging device 50 shown in FIG. 10 in the manner of a bogie and be driven into the device with this. With the help of appropriate facilities, e.g. Hydraulic cylinders 51, which are arranged on one or both end faces of the device 10, the material stack 12 is moved back and forth between the two end positions 19a and 19b covering the division of the blow box 18.

Claims (18)

1. Apparatus for flow impingement on laminar material in an arrangement with through-flow gaps

a) with at least one radial fan, wherein

b) the volumetric flow conveyed by the or each radial fan (14) blows the material (12, 32) by means of nozzles (34) or discharge channels (18)

c) which are provided offset from each other on opposite sides of the laminar material (12, 32),

d) so that a through-flow which alternates in its direction according to the offset arrangement of the nozzles (34) or discharge channels (18) is produced in the gaps (13, 33).

2. Apparatus according to claim 1, characterised in that

e) the radial fan (14) arranged above the laminar material (12, 32) delivers in two opposite directions into collecting channels (17) for supply of the nozzles (34) or discharge channels (18).

3. Apparatus according to either of claims 1 or 2, characterised in that

f) the radial fan (14) is equipped with a spiral housing (16) which discharges in two directions.

4. Apparatus according to any of claims 1 to 3, characterised in that

g) respectively adjacent to the individual discharge channels (18) on both sides of the stacked laminar material (12) are arranged return-flow spaces (20).

5. Apparatus according to claim 4, characterised in that

h) the return-flow spaces (20) collect the volumetric flow discharged from the opposite discharge channel (18) after flow through the stick of material (12), and deliver it to the intake region (22) of the radial fan (14).

6. Apparatus according to any of claims 1 to 5, characterised in that

i) the discharge channels (18) are provided in their outlet plane with a deflector grid (19).

7. Apparatus according to claim 6, characterised in that

j) each deflector grid (19) deflects the flow utilising the wall jet affect due to the partial pressure arising at cylindrically curved grid elements (23).

8. Apparatus according to any of claims 1 to 7, characterised in that

k) the cross-section of each discharge channel (18) decreases from the inlet to the outlet.

9. Apparatus according to any of claims 1 to 8, characterised in that

I) the discharge channels (18) due to screen-like aprons (24) on both longitudinal sides produce strong lateral contraction of the issuing flow similar to a Borda mouthpiece and hence reduce the expansion of the jet blown onto the stacked material (12).

10. Apparatus according to any of claims 1 to 3, characterised in that

m) for blowing a row of material (32), above and below the material (32) are arranged flow channels (35a) and (35b) with offset nozzles (34) aligned with the gaps (33) between the individual item of material.

11. Apparatus according to claim 10, characterised in that

n) the nozzles (34) are offset from each other not only on the two mutually opposed flow channels (35a) and (35b), but also on adjacent flow channels (35aa, 35bb).

12. Apparatus according to any of claims 1 to 11, characterised in that

o) several rows of nozzles (34) are supplied by a flow channel (35a, 35b).

13. Apparatus according to any of claims 1 to 3 and 10 to 12, characterised in that

p) the nozzles consists of straight pipes (36a) or bent pipes (36b) with rounded mouthpieces (37) the inside diameter of which is smaller than that of the pipes (36a, 36b).

14. Apparatus according to any of claims 1 to 13, characterised in that

q) the laminar material (12, 32) can be reciprocated in the direction of its horizontal longitudinal axis during blowing.

15. Apparatus according to claim 14, characterised in that

r) the amplitude of reciprocation of the material (12, 32) corresponds to the spacing of the discharge channels (18) or of the nozzles (34).

16. Apparatus according to any of claims 1 to 15, characterised in that

s) the intermediate layers between the laminar material are coordinated with the spacing of the discharge channels (18) or nozzles (34) and delimit from each other the alternately directed gas streams in the gaps between the layers of material.

17. Apparatus according to claim 16, characterised in that

t) the spacers or the transversely extending frame supports between the individual layers of material are coordinated with the spacing of the nozzles (34) or of the discharge channels (18).

18. Apparatus according to any of claims 1 to 17, characterised in that

u) the direction of flow in each gap between materials is the same but alternates from one gap to another.

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