EP0864519B1 - Apparatus to guide webs in a floating manner - Google Patents

Abstract

The appliance has at least one blowing section (2,3) with suspension jets (11) for blowing processing gas onto at least one side of the web (1). A radial ventilator (7,8) with a 360 degree spiral housing (22) supplies the suspension jets. The radial ventilators blow in a direction (19) parallel to the direction (27) in which the web travels. The current from the radial ventilator at each longitudinal end of each blowing section is deflected in a U-shape to the web.

Description

The invention relates to a device for floating guidance and stabilization of strips, preferably metal strips, for the purpose of heat treatment of the genus specified in the preamble of claim 1.

In such a device, the tapes are blown with treatment gas suspended from below and possibly also from above while doing so heat treated at the same time. The heat treatment can heat and hold to annealing temperature and subsequent cooling for metallurgical reasons or also for the purpose of surface treatment, e.g. B. drying one Coating the tape.

Such devices are usually made of individual, one behind the other Sections constructed and included, such as DE-OS 2446983 or DE 4010280 A1 shows, for each section, a flow guide with at least one fan and across Floating nozzle systems arranged above and below the belt for the belt run, with which the tape is used for the purpose of convective heat exchange blow the gas circulated by the fan and at the same time through the acting Flow forces is stabilized.

In particular, devices for operation at higher gas temperatures are in the Usually equipped with radial fans for strength reasons.

In the device according to DE-OS 2446983 is arranged laterally by only one Fan per section achieved a particularly compact design, but there one fan that supplies both upper and lower floating nozzles is one easy adjustment of the load capacity, e.g. B. to adapt to the weight of the floating to leading band, not by changing the fan speed possible because it affects the upper and lower nozzle systems in the same way would. In addition, the device according to DE-OS 2446983 has the disadvantage that that the backflow of the treatment gas inflated onto the belt only after one side towards the fan. This creates a backflow from the belt and inflow in the nozzle fins for a heat exchange in the Cross current, which z. B. in a heating zone in which the gas from the belt flows out colder than it is inflated onto the belt, a decrease in temperature of the inflated gas along the nozzle rib from that facing away from the fan Side to the fan side.

The device according to DE 4010280 A1 avoids this disadvantage by mutual inflow to the nozzle fins within a section, required but four fans per section and is therefore only for systems for floating Run very wide tapes where appropriate because of the larger ones to be blown Area and the higher gas volume flow required thereby this higher technical effort is worthwhile. A big disadvantage of this device with side supplied nozzle fins is that complex guide vane systems for recirculation the nozzle outflow must be used perpendicular to the belt surface, which, in addition to costs, cause noticeable pressure drops. Especially with plants for non-ferrous metal tapes made of brass, copper, bronze, nickel silver and similar materials but is the range because of compared to light metal or steel strips usually limited considerably smaller rolling width, so that the Device according to DE 4010280 A1 hardly for the hovering mostly relatively heavy and narrow non-ferrous metal tapes.

DE-A 19 623 303 discloses a device for drying material webs with a housing, inside of which by means of blowers and blow nozzle boxes each After the temperature zone, hot to slightly tempered air is blown against the material web becomes. The circulating air fan motors are in one chamber for preheating the fresh air arranged with inlet and outlet openings so that the fresh air this chamber flows through and absorbs the thermal energy from the cooling of the electric motors. The air flow emerging from the circulating air blowers, see for example FIG. 1, immediately undergoes a 90 ° bend, which results in relatively poor efficiency results. No information is given on the outflow of the circulated air.

The invention is therefore based on the object of a device of the specified To create genus that avoids the disadvantages described. In particular is to provide a technically relatively inexpensive, compact device in which the bilateral adjustment of the flow to the weight of a Band or the regulation of the load capacity in a simple manner by changing the Fan speed is possible.

This is achieved by the features formulated in claim 1. The subclaims describe advantageous execution details.

A radial fan, preferably a drum rotor radial fan, is shown in each zone with axis vertical to the belt level above and below the belt the ceiling or the bottom of a section of the device.

The discharge cross-section of the spiral casing of the radial fan is oriented in such a way that the blowout into a channel piece of at least the length of about a hydraulic Diameter, essentially parallel to the belt run.

This section of duct is connected to an end wall of a section of the device a flow deflection by 180 °, i.e. against the blow-out direction of the radial fan, on. At the end of this 180 ° deflection there is another flow channel, which is also parallel to the belt run and over the extends the entire length of the section. This channel forms in connection with the 180 ° deflection and the 360 ° spiral housing with subsequent exhaust duct, in viewed vertical longitudinal central section of the device, the shape of a horizontal lying U, whose two legs are parallel to the belt run. On the the tape facing side of the flow channel adjoining the 180 ° deflection the nozzle field is arranged. This nozzle field can be from the usual, the state of Technically appropriate floating nozzles, but preferably from a floating nozzle field with nozzle surfaces, which have the shape of the axial section of a truncated cone or a barrel, the base of the truncated cone or the largest diameter of the barrel is in the middle of the floating nozzle.

In both cases, there are between the floating nozzle ribs or the nozzle surfaces return flow channels open to the belt, the cross-section of which extends to the belt edges can expand.

It is also possible to use a nozzle surface as the nozzle field, in which nozzle openings are partially grouped around outflow openings. These outflow openings are formed by the inlet cross-section in channels, which the flow channel penetrate perpendicular to the band plane. In this case the Backflow from the belt to the fan partly through these flow channels, where the division of the backflow into the portion that is lateral to the belt flows back, and takes place in the proportion, which by the above, the Flow channel penetrating backflow channels the load capacity characteristic of Floating nozzle field determined.

In any case, however, the major part of the outflow takes place on both sides the device and comes out of the room to the side of the flow channel in the area between the two U-legs, towards which the suction opening the centrifugal fan is oriented.

Arranged on both sides of the belt and flow guide and from the the outer housing of the device enclosed spaces are accessible and can be used for inspection and maintenance work.

When heating the device with burners, heating devices are at least a side wall of the outer case installed and protrude into the space between the Legs into the U-shaped flow guide.

With electrical heating, the electrical heating register is either in the range of Deflection of the U-shaped flow guide installed or on the suction side in front of the Fan arranged.

In sections which are designed as cooling zones with a closed flow circuit are, the cooler for the circulating gas in the area of the U-shaped deflection installed, the cross section of the to increase the installation area Flow guidance - viewed from the fan - to the cooler inlet cross-section can expand. It is also the arrangement of the cooler on the suction side in front of the Fan possible.

The floating nozzles can be via the flow channel from which they are supplied will survive laterally.

At the beginning and end of the devices composed of sections gas jet seals attached to the tape inlet and tape outlet his. This embodiment is particularly advantageous when it comes to avoidance of gas exchange between the interior of the device and the external environment or between adjacent zones of a multi-zone Device special requirements are made.

Fig. 1

einen vertikalen Längsschnitt durch einen Schwebeofen mit Heiz- und Kühlzone,

Fig. 2

eine vergrößerte Darstellung der U-förmigen Strömungsführung in der oberen Hälfte der ersten Heizzone aus Figur 1,

Fig. 3

einen vertikalen Querschnitt durch eine Heizzone,

Fig. 4

einen vertikalen Querschnitt durch eine Kühlzone, und

Fig. 5

eine perspektivische Darstellung eines Ausschnittes aus einem Schwebedüsenfeld.

The invention is explained below using exemplary embodiments with reference to the accompanying schematic drawing. Show it:

Fig. 1

a vertical longitudinal section through a floating furnace with heating and cooling zone,

Fig. 2

2 shows an enlarged illustration of the U-shaped flow guide in the upper half of the first heating zone from FIG. 1,

Fig. 3

a vertical cross section through a heating zone,

Fig. 4

a vertical cross section through a cooling zone, and

Fig. 5

a perspective view of a section of a floating nozzle field.

The device shown in Figure 1 is used for floating guidance and stabilization from narrow to medium-wide metal bands. This means metal straps with a width between about 800 mm and 1200 mm. This device has, see Figure 1, four heating zones 2 and two cooling zones 3. Volume 1 is running from right to left horizontally through the device. In the end, behind the last one Cooling zone 3, the device is through a water cup 4 through which the belt 1 is guided by means of an immersion roller. Before entering the first Heating or furnace zone are the usual roles for controlling the belt position and the Belt tension arranged.

At the beginning and at the end of the device, namely heating and / or cooling zones, advantageous under protective gas or ice gas seal 12 be attached. The gas jet seal 12 at the inlet should a mixture of the protective gas atmosphere, which is preferably an extremely low one Avoid oxygen content with the ambient air. The gas jet seal 12 at the outlet of the device advantageously prevents this Penetration of water vapor from the housing of the water cup 4 into the cooling zone 3, whereby the dew point of the protective gas atmosphere is raised disadvantageously would.

Each zone 2, 3 of the device has two U-shaped flow guides 50 and 5u or 6o and 6u above the belt (5o, 60) or below the belt (5u, 6u). In the legs of this U facing away from volume 1 are heating or furnace fans 7 or cooling zone fans 8 installed. The outlet direction 19 of the fan 7, 8 in a U-shaped flow guide 5o or 5u, 6o or 6u points against the Connection of the two legs of the U. In this connection, as done by the Flow arrow 21 is indicated in Figure 2, a change in the direction of flow 180 ° into the entry of a flow channel 25, which is the second U-leg represents and from which nozzle fins 11 are supplied with treatment gas.

The great advantage of the U-shaped flow guide is that a fan 7, 8, preferably a particularly compact one with regard to the conveying capacity Drum rotor fan, in a 360 ° spiral housing - in Figure 2 by the Reference numeral 22 marked - can be used. To unfold the full fan, each fan 7, 8 is the straight blow-out section 20 of the Length about a hydraulic diameter in the, in the illustration in figure 2 shown, upper U-leg up to the flow deflection 21 available.

As can be seen in particular in Figure 2, is used to generate the U-shaped Flow guide 5, 6 an approximately U-shaped flow plate 29, which in each Section of the device is arranged. The top, flat horizontal surface of this Flow plate 29 runs parallel to the outer wall of the device and forms together with the inner surface of this outer wall, the straight blow-out section 20, whose length corresponds approximately to a hydraulic diameter. The redirection of the Flow by 180 °, indicated by the flow arrow 21, takes place, as mentioned, at the junction of the two legs of the U-shaped flow plate 29, so that the blowing gas between the lower leg of the U-shaped flow plate 29 and the nozzle surfaces of the floating nozzles 11 flows. The lower Starting from the 180 ° flow deflection, the leg is somewhat downwards inclined so that a flow channel 25 is formed, which ends with the Radial fan 7 narrowed somewhat. The resulting higher gas velocities serve to compensate for the pressure loss at the floating nozzles 11 the entire length of a section 2, 3.

As can be seen in FIG. 1, the connection points are located in two adjacent sections the leg of the U-shaped flow plate 29 on opposite one another Ends of the two sections, so that the side view is about Form of an inverted iron results.

When blowing the band 1 as shown in FIG. 1, point it from both sides the flow guides 5o, 5u, 60, 6u on both sides of the belt 1 in the same Direction, so they are arranged mirror-symmetrically with respect to the tape 1.

In the oven or heating zones 2 are in the area between the two legs of the U for the example shown in the figures indirectly gas-heated radiant tubes 9 arranged. The cooling zones 3 with gas flow in a closed circuit contain one in each U in the junction between the two U-legs arranged cooler 10. This cooler 10 can be used as a finned or finned tube cooler or be carried out in another usual design.

In cross section through a heating zone 2 (Figure 3) are rooms 13 to the side of the U-shaped flow guide 5o and 5u can be seen. These rooms 13 are in usually through manholes, which can be screwed gas-tight; accessible and allow easy inspection and cleaning of the device and easy access for maintenance work.

The radial fan 7 is driven in the example shown by a belt drive. The motor 15, the fan 7 on the side of the device is advantageous relocated because then only the V-belts to remove the fan 7 must be dismantled and the heavy motor 15 with its electrical connections can remain on the system.

In the example shown, an auxiliary motor 18 can also be seen, which is driven by a Emergency generator is driven and the fan 7 continues to rotate offset if, e.g. B. by a power failure, an unintentional downtime occurs. This auxiliary motor 18 then prevents the fan 7 stops and is damaged at high temperatures inside the furnace could.

The structure of the cooling zone 3, which is shown in cross section in Figure 4, corresponds essentially the structure of the heating zone 2. The fan 8 is also by a laterally arranged motor 16 driven by a belt drive. inspection and inspection rooms 14 result from the area between the U-shaped Flow guide 6o or 6u and the outer housing.

The device can be equipped with various floating nozzle systems. Figure 2 shows the equipment with floating nozzle ribs 11 according to the state of the Technology. These nozzle ribs 11 are with slot nozzles or perforated nozzles or one Combined with perforated and slotted nozzles, they run across the belt run and have the same width across the entire working width. If on both sides of the band 1 floating nozzles 11 are arranged, these are expedient offset by half the pitch, as in the prior art generally known, in the case of thin, moving with little pull through the device Tapes 1 can impress a transverse wave form that stabilizes the tape run.

The outflow of the gas stream inflated from the nozzle ribs 11 onto the belt can take place through return flow channels 24 which are located between the nozzle ribs 11 are trained. The gas flows laterally out of these return flow channels 24 Flow channel 25 between the nozzle surface and flow plate 29 over, which shown in Figure 2 with decreasing in the flow direction in the channel 25 height is. Then, as indicated by the flow arrow 26, the outflow occurs Gas flow into the suction area 22 of the radial fan 7, namely into 360 ° spiral housing.

A new type of floating nozzle field is shown in FIG. Nozzle surfaces whose Width extends transversely to the tape running direction indicated by the arrow 27 in FIG changed, are lined up one behind the other in the tape running direction. These nozzle areas are framed by slot nozzles 17 in part of their circumference. The nozzle surfaces themselves are equipped with perforated nozzles.

For the backflow there are backflow channels 24 between the nozzle surfaces Available, their cross-section from the supply center to the two edges increases because the top of the flow channel 25 is approximately gabled in shape, like one recognizes in Figure 5.

The nozzle surfaces have an elongated, tapered shape when viewed from above, such as through an axial section of a truncated cone or a barrel is formed, the base of the truncated cone or the largest diameter of the barrel lies in the middle of the floating nozzle 11.

The slot nozzles 17 extend over the entire circumference of the nozzle surfaces except for their blunt ends, as can be seen in Figure 5.

Finally, there is the design of the device with a continuous Floating nozzle surface possible, which the side facing the volume 1 of the Flow channel 25 forms. To facilitate the backflow can be in the middle this surface channels are arranged, which the flow channel 25 into a Penetrate direction perpendicular to the belt and in this way the outflow a part of the gas stream inflated onto the belt 1 with the nozzle openings allow directly to the suction area of the radial fan 7, 8. Much of the overall volume flow inflated onto the belt continues to flow sideways and reaches the suction area of the radial fan 7, 8, as by the flow arrow 26 is indicated.

In this embodiment, the nozzle openings are expediently in groups arranged around the return flow channels penetrating the flow channel, which are preferably only present in the central region of the flow channel. The advantage this embodiment is, on the one hand, that a smooth surface is available, on which there are sensitive tapes even when pulling into the device nowhere to get stuck and that the manufacturing cost because of the simple Components are comparatively small.

Claims (12)

1. An apparatus for levitational guidance and stabilisation of webs (1), preferably metal webs (1), for the purpose of its heat-treatment, comprising at least one jetting section (2, 3), and comprising:

   a) levitation nozzles (11) for jetting the web (1) at least on one side with a treatment gas; and

   b) a radial fan (7, 8) arranged on the jetting side of the web (1) and including a 360° spiral housing (22) for feeding the levitation nozzles (11); comprising the following features:

   c) said radial fan (7, 8) with an internal intake opening is disposed at each jetting side in the transport direction of said web respectively at one longitudinal end of each jetting section (2, 3);

   d) said radial fan (7, 8) is arranged so that it delivers in a direction (19) located substantially parallel to said transport direction (27) of said web;

   e) a straight ducting length (20) is connected to the delivery cross-section of said radial fan (7, 8), which is roughly as long as a hydraulic diameter;

   f) the flow from said ducting length (20) is returned (21) at the respective other longitudinal end of each jetting section (2, 3) in the shape of a U to said web (1) so that in the region of said levitation nozzles (11) the flow again runs in a flow passageway (25) substantially parallel to said transport direction (27) of said web as a counter current to said flow (19) from said radial fan (7, 8); and

   g) the return flow from said web (1) occurs initially parallel to the plane of said web to a space (13, 14) laterally adjoining the flow ducting (So, 5u; 6o; 6u) and from this space (13, 14) into the region between said flow from said radial fan (7, 8) and said flow at said levitation nozzles (11) and to the intake cross-section of said radial fan (7, 8).
2. The apparatus as set forth in claim 1 with jetting on both sides characterised in that said flow ducts (So, 5u; 60, 6u) guide the flow in the same direction on both sides of said web (1) and are thus arranged mirror-symmetrical to said web (1).
3. The apparatus as set forth in at least one of claims 1 or 2, characterised in that each radial fan (7, 8) is a compressor drum.
4. The apparatus as set forth in at least one of claims 1 to 3, characterised in that each of the spaces (13, 14) arranged on both sides of said web (1) and said flow ducting, encompassed by the outer housing of said apparatus, are accessible for inspection and maintenance tasks.
5. The apparatus as set forth in one or more of claims 1 to 3, characterised in that for heating said apparatus with burners, heating means (9) are incorporated in at least one side wall of said outer housing and protrude into the space between the parallel opposing flow sections, or for electrically heating, an electrical heating register is incorporated in the region of said U-shaped return flow.
6. The apparatus as set forth in at least one of claims 1 to 5, characterised in that in sections configured as closed-circuit cooling zones (3) the cooler (10) for the circulating gas is incorporated in the region of said U-shaped return flow, the cross-section of said ducting (60), (6u) being flared towards the cooler inlet cross-section, as viewed from said radial fan (8), to increase the installation surface area.
7. The apparatus as set forth in at least one of claims 1 to 6, characterised in that at the web inlet and outlet openings gas jet seals (12) are mounted at the beginning and end of said apparatus composed of at least one jetting section (2, 3).
8. The apparatus as set forth in at least one of claims 1 to 7, characterised in that, for levitational guidance of said web (1), levitational nozzles (11) are employed, equipped with at least one of either slotted nozzles (17) or orifice nozzles (20), having unequal width over the width of said web, wherein between said levitational nozzles (11), return flow passageways (24) are formed permitting lateral outflow of the gas jetted to said web (1) and in that said levitation nozzles (11) protrude laterally beyond the flow passageway (25) through which said levitation nozzles (11) are supplied.
9. The apparatus as set forth in claim 8, characterised in that each levitation nozzle (11) arranged transversely to said web (1) comprises two outer nozzle slots (17) encompassing its nozzle surface area in the form of the axial section of a double truncated cone or a barrel, the base of said double truncated cone or the largest diameter of said barrel being located in the middle of said levitation nozzle (11), and in that the jets (28) of a levitation nozzle (11) exiting said two nozzle slots (17) are inclined towards each other.
10. The apparatus as set forth in at least one of claims 8 or 9, characterised in that orifice nozzles (20) are arranged between said nozzle slots (17) of a levitation nozzle (11).
11. The apparatus as set forth in at least one of claims 1 to 10, characterised in that said flow passageway (25), as viewed in the vertical longitudinal centre section of said apparatus forming said U-leg adjoining said web (1), is equipped at its side facing said web with a nozzle area comprising, in its middle region, return flow passageways (24) passing through the flow passageway perpendicular to said web, nozzle apertures being clustered around said return flow passageways.
12. The apparatus as set forth in at least one of claims 1 to 11, characterised in that said web (1) to be stabilised is transported inclined with respect to the horizontal.

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