EP1399276B1 - Method and nozzle arrangement for a variable-width lubrication of the rolling nip of a rolling stand - Google Patents

Abstract

The invention relates to a method for lubricating rolls, in particular for lubricating a rolling nip in rolling stands for rolled strips. According to the invention, said lubrication takes place using an oil-in-water dispersion whilst maintaining both a predetermined blend characteristic and a volumetric flow of the dispersion. The dispersion is prepared in the form of a homogeneous blend in a mixer ( 1 ) using adjustable quantities of water and oil. The dispersion is supplied to various spray zones (Zi) for a distribution (Bi) that is variable in width. Said method for roll lubrication can be improved by the allocation of at least one row of nozzles (Di) to each spray zone (Zi), which has a corresponding spray range width (Bi), each nozzle being controlled by at least one relay valve (Si).

Description

The invention relates to a method for roller lubrication, in particular for Rolled-gap lubrication, in rolling mills for rolled strip with an oil-in-water dispersion under specifiable compliance with both a mixing characteristic as well as a volume flow of the dispersion, which in a mixer with adjustable proportions of water and oil to a homogeneous dispersion prepared and different for the bandwidth variable distribution Spray zones is abandoned and each spray zone with an assignable Spray width is assigned at least one row of nozzles, each of is controlled at least one switching valve. The invention also relates to a Nozzle arrangement for carrying out the method according to the invention.

Of crucial importance for the effectiveness of roll lubrication, in particular the roll gap lubrication, in rolling stands for the production hot strip is the production of a dispersion in the form of a water-in-oil mixture from oil droplets in the water, but they are not dissolved in each other and whose composition is constant. At the same time, this dispersion must be in Regarding the rolling bandwidth with the requirement of a width-dependent Rolling or roll gap lubrication be reconciled.

In known roll-gap lubrication, the maintenance of the mixing conditions with only one mixer, the so-called mixer the connection of nozzles to extend the width of spray zones not be respected. The dispersion is produced in the mixer. In these flows Water with presettable amount at a given pressure and thus assigned Flow velocity through the mixing system. The flow velocity can be an essential factor in the mixing process be considered.

If now, as for example in the scheme of a rolling gap lubrication according to the state the technique shown in FIG. 1 is shown, depending on the width connected nozzles thereby increasing the amount of water. Because this amount of water always through the same cross-section in the mixer and through the subsequent piping system must flow through, according to the continuity equation the flow velocity too. If doing the mixing of oil and Water is designed to the maximum flow, the effect is added minimal bandwidth and thus with minimal flow due to decreasing Flow velocity significantly lower. Also, the stability decreases the dispersion during the flow through the supply line to the tubes from.

As shown in the example of FIG. 1, in a structure of a Width-dependent roll gap lubrication e.g. ten nozzles of three groups each connected. The minimum rolling bandwidth requires four nozzles. Depending on the bandwidth Then two additional nozzles are switched on sequentially. This results in purely mathematical nonuniformity of 4/10 or 1 / 2.5 for the amount of water.

Now, if this disadvantage should be eliminated, several mixers and This also means that several pumps with piping per bandwidth are used come to achieve always ideal flow and mixing ratios.

The document EP 1 040 877 A1 shows a device for roller lubrication or for roll-gap lubrication of the rolls in a roll stand. The spray device, which corresponds to the aforementioned prior art, shows three switching valves. The spent dispersion is collected, in the different Phases of water / oil separated and after reprocessing in the device fed. This is an emulsion with 2% oil in water in a Mixer tank prepared and mixed by a stirrer. The device is with Triple dovetail nozzles for a flat, wide-spreading Spray formed.

Document EP 0 367 967 B1 describes a method for cooling and Lubrication of rolls in a rolling stand during cold rolling of metal strips under supply of emulsifiers and at least one oil phase containing Oil / water emulsion by means of nip emulsion nozzles, wherein the emulsion before the rolls of the rolling stand or before the strip inlet in the of Work rolls formed nip in a disperser by separate feeding the emulsion forming media is prepared and the emulsion collected after the completion of their cooling / lubricating function behind the roll stand, separated and the separated liquid phases separately to form the input emulsion be used.

With this emulsion circulating system, any oil concentration in the Emulsion at any time and with extremely little time delay to the respective Specifications of the rolling process can be adjusted. As a result of the delay-free Flexibility of the cooling and lubrication system for cold rolling mills is better Product quality with regard to the surface quality and flatness of the rolled strip reachable. In addition, the treatment of the emulsion is simplified and environmentally friendly, at the same time the equipment costs in the Be reduced compared to known emulsion circulating systems.

Document EP 0 776 710 A1 discloses a device for influencing the profile of rolled rolled strip. To possible during cold rolling of tape To counteract emerging "edge drops" is proposed, the band edge contact areas To cool the work rolls regulated by means of the effect caused by the cooling change in the crown essentially counteracted by the Materialquerfließverhalten caused "edge drops" is regulated. For this purpose, in each case the two end regions of the bales of the rollers further spray bars assigned, the scope of each of a bale end in the region of the rolled strip edge facing this bale end extend beyond.

According to the document JP-A-03-128113 is for a significant shortening of the time delay in the injection stop of rolling oil a shut-off valve on the outlet side of a mixer with a connecting line for hot water, bypassing the mixer and the closing valve equipped.

Based on the aforementioned prior art, the invention has the object to provide a method and a nozzle arrangement, with the spray different rolling belt widths, whereby one of constant, adjustable volume flow of the water is assumed and the mixture of the phases water / oil should always remain constant (ideal).

To solve the problem, the inventive method for roller lubrication, in particular for roll gap lubrication, in rolling mills for rolled strip according to the preamble of claim 1 above, that in each case only one Switching valve the total dispersion amount of a spray zone is discharged, and each nozzle row is designed so that the total number of their nozzle holes with activated switching valve always the same amount of dispersion discharges and thus the flow conditions in the mixer for each spraying zone remain unchanged.

Further embodiments of the method are corresponding to the associated Dependent claims provided.

A nozzle arrangement for roller lubrication, in particular roller gap lubrication in rolling mills for rolled strip for carrying out the method This is characterized by the fact that in each case one for the predeterminable Sprühmittel volume flow required number of spray nozzles of a spray zone in one separate nozzle row is arranged, each with at least one controllable Switching valve communicates, and that each nozzle row so is designed so that their total number of nozzle holes are the same Volumetric flow result. By this measure, the flow conditions remain in the dispersion mixer and thus the mixing of Wasserund Oil shares always constant. Decisive for the mixing is therefore the Flow rate of the water and not the amount of oil.

Further embodiments of the nozzle arrangement are in accordance with the subclaims intended.

1. Bis 900 mm Bandbreite:
Wasser ca. 20 l/min + 0,25 l/min Öl = 20,25 l/min

2. Bis 1350 mm Bandbreite:
Wasser ca. 20 l/min + 0,3 l/min Öl = 20,30 l/min

3. Bis 1800 mm Bandbreite:
Wasser ca. 20 l/min + 0,40 l/min Öl = 20,40 l/min

With these measures, advantageously, for example, the following rolled strip widths can be sprayed:

1. Up to 900 mm bandwidth:
Water approx. 20 l / min + 0.25 l / min Oil = 20.25 l / min

2. Up to 1350 mm bandwidth:
Water about 20 l / min + 0.3 l / min oil = 20,30 l / min

3. Up to 1800 mm bandwidth:
Water approx. 20 l / min + 0,40 l / min Oil = 20,40 l / min

With the claimed method ideal mixing independent of width produced using only a single mixer with pump, piping and Return for all bandwidths is required and there are only three Switching valves of the same series for controlling the dispersion quantity for all spray zones required.

By the measure according to the invention, according to which each nozzle row designed so is that the total number of their nozzle holes when driven Switching valve always discharges the same amount of dispersion is achieved with advantage that the flow conditions in the mixer for each spray zone unchanged stay. This will always ideal and comparable conditions maintained.

Furthermore, the method according to the invention provides that for an increasing Width adjustment of individual spraying zones additionally the proportionate oil quantity in the dispersion is increased, for example, from 0.25% to 0.40%.

Finally, the method according to the invention provides a further embodiment in that the opening angle α of the nozzle bores and / or their Number is formed in accordance with the spray width of each nozzle row.

In a further advantageous embodiment of the invention, it is provided that the Nozzle rows in a nozzle bar at approximately the same distance parallel are arranged to the rollers or to the nip. The width setting is then about the nozzle spacing of each nozzle row, the opening angle of Nozzles, the number of nozzles or a combination of opening angle, number and distance in each row exactly tunable.

Further advantageous embodiments of the nozzle arrangement are in others Subclaims specified.

Figur 1

das Funktions- und Schaltschema einer Vorrichtung zur Walzenschmierung nach dem Stand der Technik,

Figur 2

eine Vorrichtung zur Walzenschmierung nach der Erfindung.

Details, features and advantages of the invention will become apparent from the following explanation of an embodiment schematically illustrated in the drawing. Show it:

FIG. 1

the functional and circuit diagram of a device for roller lubrication according to the prior art,

FIG. 2

a device for roller lubrication according to the invention.

The apparatus shown in Fig. 1 of a rolling gap lubrication or roller lubrication in a roll stand not shown with width adjustment In the prior art shows a water supply 2 and an oil line 3. Both media are supplied to the device under pressure. With the reference numbers 4 and 7 are each flow meter for the two media water and oil. The number 6 shows a metering pump for a proportionate metering small amounts of dispersion oil. With the number 1 is a in itself known mixer, in which the two media water and oil with each other be intimately mixed. S1 to S3 are three switching valves, the example. By means of compressed air 9 are switched individually. Each of these switching valves S1 to S3 is connected to a spray zone Z1 to Z3.

In the example shown, the spraying zone Z1 is assigned four spray nozzles d1 to d4. The spray zone Z2 are four switchable nozzles d6 and the spray zone Z3 are also associated with two further spray nozzles d7.

Now, as shown for example in Fig. 1, the zone Z1 is the width-dependent Nozzles d6 and d7 of zones Z2 and Z3 are switched on, then the required number decreases Amount of water too. Because this amount of water is always through it Cross-section in the mixer 1 must flow, takes the flow velocity with the switching of the switching valves S2 and S3 respectively. When doing so the Mixing of oil and water is designed for maximum flow The effect is minimal bandwidth and thus with minimal amount of water decrease a lot. Also, the stability of the dispersion during the flow through the supply to the tubes decreases.

As shown in Fig. 1, in the example shown, a total of ten Nozzles in three spray zones Z1 to Z3 interconnected. It requires the minimum Bandwidth four nozzles d1 to d4. Depending on the bandwidth then up to six Nozzles, three nozzles d5, d6 d7 on the right and three nozzles d5, d6 d7 on the left switched on. In purely mathematical terms, this results in a nonuniformity of 4/10 or 1 / 2.5 for the amount of water.

With the embodiment of a device for roller lubrication shown in Fig. 2 with an oil-in-water dispersion is the disadvantage of the device according to Fig. 1 avoided.

The circuit diagram of the device according to the invention according to FIG. 2 shows also the supply line 2 for water and the line 3 for oil and the flow meter 4 for water and the flow meter 7 for oil. With the reference numerals 5 and 8 are pressure gauge for water and oil designated and with the Reference numeral 6 indicates a metering pump for oil metering.

The media water and oil are intimately mixed in the mixer 1 to a homogeneous dispersion edited. This dispersion is a water-in-oil mixture of the smallest Oil drops in the water. The dispersion becomes a broad variable distribution on the non-illustrated rollers of a rolling mill initially three Switching valves S1 to S3 and fed from these the way to the different Spray zones Z1 to Z3 released. Each one of the switching valves S1, S3, S2 is associated with a separate spray zone Z1 to Z3. Every spraying zone Z1, Z2, Z3 has an associated spray width B3 to B1 with an associated Nozzle row D3 to D1 on.

With this nozzle arrangement according to the invention it is achieved that over each only one switching valve S1 to S3 the total dispersion amount of a connectable Spraying zone Z1 to Z3 for the width B3 to B1 of an associated row of nozzles D3 to D1 is discharged. Each nozzle row D3 to D1 is designed to that the number of their nozzle bores with activated switching valve S1 to S3 always discharges the same amount of dispersion, and thus the flow conditions remain unchanged in the mixer 1 for each spraying zone Z1 to Z3. For an increasing width adjustment of individual spray zones is additionally the proportional amount of oil in the dispersion, for example. Increased from 0.25% to 0.40%. For a decreasing width adjustment, the proportionate amount of oil in the dispersion reduced accordingly.

The opening angle α shown in FIG. 2 of the nozzle bores and / or their Number is in accordance with the spray width B3 to B1 each nozzle row educated. Each nozzle row D3 to D1 is designed so that its nozzle bores each result in the same volume flow and consequently the Flow conditions in the mixer 1 and thus the mixing of Wasserund Oil shares always remain constant.

• breitenunabhängig ideale Durchmischung
• nur ein Mixer für alle Bandbreiten
• z.B. nur drei Schaltventile einer Baureihe für die gesamte Dispersionsmenge für beispielhaft drei Sprühbreiten.

Particularly recognizable in Fig. 2, the arrangement according to the invention that the nozzle rows D1 to D3 and the züordenbaren switching valves S2, S3, S1, only a single mixer is associated with a corresponding connection for water and oil. This outweighs the slightly increased number of nozzles over the prior art. The advantages of the nozzle arrangement according to the invention are:

• independent of the width ideal mixing
• just a mixer for all bandwidths
• For example, only three switching valves of a series for the entire amount of dispersion for example, three spray widths.

Claims (6)

1. Method of roll lubrication, particularly for roll gap lubrication, in roll stands for rolled strip by an oil-in-water dispersion with predeterminable maintenance not only of a mixture characteristic, but also of a volume flow of the dispersion, wherein this is prepared in a mixer (1) with settable quantity proportions of water and oil to form a homogeneous dispersion and is delivered to different spray zones (Z_i) for distribution (B_i) variable over strip width, and at least one nozzle row (D_i), which is respectively controlled by at least one switching valve (S_i), is associated with each spray zone (Z_i) with an assignable spray strip width (B_i), characterised in that the total dispersion quantity of a spray zone (Z_i) is discharged each time by way of only one switching valve (S_i) and each nozzle row (D_i) is so designed that the total number of the nozzle bores thereof when the switching valve (S_i) is controlled in drive always discharges the same quantity of dispersion and thus the flow ratios in the mixer (1) for each spray zone (Z_i) remain unchanged.
2. Method according to claim 1, characterised in that for an increasing width adjustment of individual spray zones (Z_i) the proportional oil quantity in the dispersion is additionally increased, for example from 0.25% to 0.40%.
3. Method according to claim 1 or 2, characterised in that the opening angle (α) of the nozzles and/or the number thereof and/or the spacing thereof is formed in accordance with the spray strip width (B_i) of each nozzle row (D_i).
4. Nozzle arrangement for roll lubrication, particularly roll gap lubrication in roll stands for rolled strip, for carrying out the method according to one of the preceding claims, characterised in that each time a number, which is required for the predeterminable spray medium volume flow, of spray nozzles of a spray zone (Z_i) is arranged in a separate nozzle row (D_i) connected in each instance with a controllable switching valve (S_i) and that each nozzle row (D_i) is so designed that the total number of nozzle bores thereof each time gives the same volume flow.
5. Nozzle arrangement according to claim 4, characterised in that the nozzle rows (D_i) are arranged in a nozzle bar at approximately equidistant spacing parallel to the rolls or to the roll gap of the roll stand.
6. Nozzle arrangement according to claim 4 or 5, characterised in that only a single mixer (1), with a corresponding connection for water and oil, as well as metering pumps (6) and throughflow meters (4, 7) arranged in the connecting ducts, is associated with the nozzle rows (D_i) or with the switching valves (S_i).

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