CN213530190U - Cooling element - Google Patents

Abstract

The present invention describes a cooling element for cooling a long product along a material flow, wherein the device features a plurality of nozzles for releasing coolant onto the long product, which nozzles are arranged circumferentially around the material flow. The nozzles are arranged at even intervals in the circumferential direction so that the coolant can be uniformly discharged onto the long product, being distributed throughout the circumferential direction.

Description

Cooling element

Technical Field

The utility model relates to a cooling element for cooling long product.

Background

The rolling process of hot metal bars, wires and pipes requires the use of so-called cooling lines. These cooling lines serve to intentionally influence the microstructure of the material by cooling the hot rolled product. In rolling mills, cooling lines are arranged at different positions before or after the individual rolling stands of the rolling line and usually consist of a water box and a subsequent equalization zone. The long product is cooled in a water tank. Since the cooling process cools the surface of the rolled product, an equalization zone is typically behind the water box in order to even out the reduced surface temperature with the core temperature of the product.

The long products within the framework of the invention are semi-finished products manufactured by rolling, drawing or forging while keeping the cross section constant along the length. In contrast to flat products, their length is greater than the thickness/height and width. In particular, long products include rods, wires, tubes and profiles.

In the framework of the present invention, the production line or rolling line is a main straight line or line segment, along which the long products move through the production device.

On its way through the cooling circuit, the long product passes through several different cooling and equalization zones. Without the provision of an equalization zone, excessive cooling of the product surface would result in surface "freezing" while the core temperature of the material is still high, resulting in an insufficient microstructure of the finished product.

The microstructure of the finished product is thus particularly affected by the cooling process.

The meaning of this is twofold: on the one hand this means that the equalization zone described above needs to be in place after each cooling element, and on the other hand, if applicable, the plurality of cooling elements each followed by an equalization zone must be in place.

Furthermore, the cooling that takes place in the cooling line for the long products being processed must be carefully controlled in order to achieve the desired cooling process. The amount of cooling required varies depending on the requirements of the finished product.

Thus, a cooling line comprises a plurality of cooling elements fed with a coolant, which release the coolant to the surface of the passing product in order to cool said surface.

By way of example, document EP 2274113B 1 discloses a device for conditioning the cooling of hot-rolled sheet or strip metal using a plurality of cooling elements. However, EP 2274113B 1 does not disclose the possibility of controlled cooling of long products. None of the prior art discloses the possibility of individually adjusting the cooling conditions of individual sections of the rolled product along the material flow.

Such adjustment or control of the cooling conditions of the individual zones may be necessary, for example, in order to influence the microstructure in a desired manner by applying an adjusting and/or controlled cooling process.

Furthermore, especially for long products, it is particularly desirable to provide uniform cooling conditions over the entire circumference of the long product. The inventors of the present invention have determined that uneven cooling over the circumference results in different microstructures; this is a fact not shown in the prior art.

In order to achieve the best cooling result, it is important to adjust the cooling line for the long product to be cooled: generally, the cooling line comprises a series of annular cooling elements, such as cooling nozzles, arranged in series coaxially, and one or more water stripping towers through which the hot rolled material passes centrally. Pressurized water is fed through the nozzle gap into the cooling nozzle until the cooling tube is completely filled. Generally, the amount of water used is 50m³In the range of/h. It is essential to guide the rolled material in as perfect an alignment as possible in the centre of the cooling tube in order to achieve a uniform cooling result over the circumference of the rolled material.

Further, it is important that the nozzle gap between the rolled material and the cooling pipe filled with the coolant does not exceed a certain size or does not fall below a certain size. Therefore, it is necessary to use a plurality of cooling elements having different inner diameters suitable for different rolled material diameters. For example, three different cooling tube diameters are necessary in order to cover a product range of rolled material diameters from 20mm to 100mm with acceptable quality.

It has proven a technique to arrange several cooling paths each adapted to a specific rolled material diameter in one cooling box so that the cooling paths can be quickly inserted into or removed from the production line in case of product changes. Since product changes can occur several times a day, the speed at which such changes are made is critical to the efficiency of the mill, since the mill must be stopped during this process.

Due to the different product requirements, it is not always necessary to run a complete sequence of hot-wire treatments for long products in a hot rolling mill. For example, only a part of the cooling elements that meet the cooling line may be in operation in order to cool long products.

Furthermore, it may be necessary to set different coolant volume flows for different long product diameters in order to accommodate the size and heat capacity of the long product. In order to do so, the amount of coolant dispensed by the cooling element needs to be finely set. However, the adjustability of such valves depends on the operating point of the valve. For example, in contrast to several DN65 valves, the DN200 valve only allows for significantly less stable adjustment of the volume flow in a small volume range.

Another problem found in the prior art is uneven cooling of the long product over its diameter. Typically, a coolant is dispensed through the nozzle gap onto the long product in order to cool the long product (see EP 3395463B 1). However, due to this, the point where the coolant hits the surface of the long product is subjected to strong cooling, which may result in the formation of a martensitic structure at the point of impact. Other areas over the circumference of the long product are subject to less cooling than other areas over the circumference of the long product, resulting in uneven cooling conditions over the circumference of the long product. From the perspective of the inventors of the present invention, such non-uniformities result in the formation of undesired microstructures and thus in undesired material properties of the finished product.

SUMMERY OF THE UTILITY MODEL

Against this background, it is an object of the present invention to provide a device for cooling long products, which device is capable of flexibly influencing the microstructure of hot-rolled long products. This is done on the one hand by creating the possibility of setting suitable cooling conditions for the production conditions with low pressure and/or volume flow, and on the other hand by achieving a uniform cooling of the hot rolled material.

This object is achieved by a cooling element for cooling a long product along a material flow, wherein the cooling element features a plurality of nozzles for releasing a coolant onto the long product, which nozzles are arranged circumferentially around the material flow, which nozzles are arranged at regular intervals in the circumferential direction, so that the coolant can be released uniformly onto the long product and distributed over the entire circumferential direction. Advantageous embodiments of the invention result from the following description.

According to the present invention, a cooling element or device for cooling a long product along a material flow is provided, in particular with regard to the further description thereof in the following sections.

The cooling element features a plurality of nozzles for releasing coolant onto the long product, which nozzles are arranged circumferentially around the material flow. The nozzles are arranged regularly in the circumferential direction, in which case the coolant can be discharged uniformly in the circumferential direction onto the long products. That is, the nozzles are arranged at regular intervals in the circumferential direction so that the coolant can be uniformly discharged onto the long product and distributed throughout the circumferential direction.

The preferred coolant is water.

A plurality of nozzles are arranged in the circumferential direction around the long product to be cooled in order to reliably achieve uniform cooling of the long product along its circumference.

Such uniform cooling facilitates uniform cooling conditions throughout the circumference of the long product, thus permitting the formation of a homogeneous microstructure in the circumferential direction of the long product. In other words, this cooling achieves uniform cooling at every point of the material.

It is preferred to use spray nozzles arranged circumferentially. Furthermore, advantageously, the nozzle is a spray nozzle configured as a flat spray nozzle.

In contrast to drop nozzles, which release coolant drop-wise, for example following gravity, spray nozzles are defined as nozzles that use pressure to pressurize a liquid through an opening. This is particularly advantageous in the case when the coolant has to be sprayed upwards or sideways against the force of gravity towards the long product. Furthermore, the spray nozzles are able to disperse the coolant, allowing for finer adjustment of the amount of coolant applied. Furthermore, this dispersion spreads the specific surface area of the coolant, which allows better utilization of the coolant and reduces consumption of the coolant.

The use of spray nozzles reduces the consumption of the required coolant, which (in addition to increased efficiency and more favourable environmental impact) allows a finer adjustment of the cooling process to the production process of the individual materials, thereby deliberately achieving individual technical properties and microstructure formation.

Preferably, the nozzles are arranged in at least two consecutive rings with respect to the material flow, and preferably alternately in the circumferential direction within consecutive rings, in order to achieve a uniform cooling throughout the circumference of the long product.

According to another preferred aspect of the invention, the device features a coolant supply pipe for supplying coolant and a plurality of cooling elements, each connected to the coolant supply pipe via an individually adjustable control valve. The release of coolant by the cooling elements is each dependent on the opening degree of the respective control valve, so that the distribution of coolant along the material flow can be flexibly adjusted due to the individual adjustment of the opening degrees of the control valves.

According to another preferred aspect of the present invention, the device is characterized by comprising a cooling line and an equalization zone, wherein the equalization zone is characterized by a discharge outlet for draining coolant from the long product.

The cooling element is used to apply a coolant to the long product to be cooled. Each of the cooling elements is connected to a coolant supply pipe via an individually adjustable control valve, allowing to modify the release of coolant from each of these thus connected cooling elements onto the long product via adjustment of the opening degree of the respective control valve.

The term "release of coolant" in this context refers to the coolant volume flow, i.e. the volume of coolant per time unit.

In this context, a control valve is defined as being able to adjust the release of coolant in the area around its operating point by changing its opening degree.

In this context, "distribution of the coolant" means that the share of the coolant distributed to the individual cooling elements is adjusted by individually setting the respective control valve when it relates to the amount of coolant supplied via the coolant supply pipe.

If the cooling elements are arranged along the material flow of the long product, the cooling program adapted to the microstructure requirements of the long product can be selected by adjusting or controlling the control valves in different regions of the cooling device.

Providing a plurality of controllable, individually adjustable valves allows for finer adjustment of the cooling conditions than would be possible with only one central valve. In conventional arrangements, the release of coolant through the cooling elements is collectively regulated by a single valve, while the provision of multiple control valves at individual cooling elements allows for precise adjustment of the cooling conditions. For example, one central control valve, which regulates the entire release of coolant by the cooling elements running through the cooling line, is necessarily designed for one of the operating ranges of the volume flow rate sufficient to supply all the cooling elements with a maximum coolant volume flow rate as well as a minimum coolant volume flow rate. However, this operating range of appreciable size makes it impossible to fine-tune the coolant flow rate in the entire volume range from a minimum coolant volume flow to a maximum coolant volume flow. In contrast, the provision of a plurality of control valves (each of which affects the coolant flow rate of only one single cooling element) has the advantage that: each of the individual control valves has a narrower operating range within which the amount of coolant supplied can be more precisely adjusted. In other words, using a plurality of individual control valves with a narrow operating range each achieves a much finer quality of control of the cooling conditions along the material flow than is possible when using one central valve with a wide operating range.

Preferably, the opening degree of the at least one control valve or preferably of the plurality of control valves is infinitely variable.

Infinitely variable in this context refers to any form of continuous adjustment that conforms to common manufacturing and control tolerances.

In particular, a control valve is a valve characterized by at least one range, after setting fully closed and fully open, in which an adjustment of the opening degree of the control valve causes a continuous change in the resulting flow rate.

Preferably, the total amount of coolant released by the cooling element is equal to the total amount of coolant supplied by the coolant supply pipe.

This means that the total amount of coolant supplied via the coolant supply pipe is distributed among the cooling elements. The effect of this is twofold: on the one hand, the distribution of the total coolant volume flow over the individual cooling elements is adjusted by adjusting the opening degree of the control valve at the cooling element. On the other hand, adjusting the total coolant volume flow in the coolant supply pipe allows presetting the total cooling capacity of the cooling device. The exact distribution over the individual zones is effected by the control valves at the cooling elements.

Preferably, the coolant supply pipe features a latching valve in order to allow or prevent supply of coolant, optionally with a specified coolant flow rate, to the cooling element via the coolant supply pipe.

The term latching valve is intended in particular to mean an "on-off valve", i.e. a valve which is characterized by exactly two settings, i.e. an open position which permits a specified flow rate and a latching position which completely closes the volume flow.

In particular, the term "lockout valve" is used herein to distinguish from the term "control valve": the latching valve, when opened very slowly, permits a flow rate of zero flow that corresponds neither to the above-specified flow rate nor to the latched position. However, the expert knows that such a valve is not considered a control valve within the framework of the present invention, since the intermediate phase between full opening and locking is undefined.

Preferably, the device is further characterized by: measuring means for measuring the pressure of the coolant in the coolant supply pipe and/or measuring means for measuring the pressure of the coolant between the control valve and the respective cooling element and/or measuring means for measuring the temperature of the long product passing through the device.

Such a coolant pressure measured by a measuring device located in front of and/or behind the control valve can be used to draw conclusions about the amount of released coolant regulated by the control valve, in particular if the characteristic curve and/or the opening degree of the control valve is known. These values may be suitable for controlling, adjusting or setting the cooling conditions.

The temperature of the material measured by the temperature measuring device may be used as a basis for determining the amount of coolant fed to the cooling element, in particular if the temperature value corresponds to a point that will be affected by the cooling applied by the cooling element.

Preferably, the cooling elements are arranged continuously along the material flow, such that each cooling element cools a section of the long product along the material flow.

By means of a continuous arrangement of a plurality of cooling elements, the material can be cooled to a first surface temperature, for example in a first cooling element, then the surface and core temperatures can be equalized while passing through an equalization zone, and can be cooled to a second surface temperature in a second cooling element, and so on. This continuous arrangement of a plurality of cooling elements makes it possible to achieve a strong heat dissipation without the surface of the long product cooling too much in one of the cooling elements to possibly trigger the formation of undesired microstructures.

Preferably, the device also features a measuring device that determines the position of the long product passing through the device.

Determining the location of the long product can help match the cooling procedure to the material if the dimensions of the long product are known. Furthermore, this positioning allows those cooling elements that do not currently hold long products to be switched off, resulting in a more energy efficient and better environmental impact of the device.

Further advantageous embodiments of the invention result from the following description of the figures and the overall description of the claims.

Drawings

Fig. 1 shows a schematic circuit diagram of a cooling device into which the present invention can be inserted.

Fig. 2 shows a cross-sectional view of a cooling element according to an embodiment of the invention.

Detailed Description

Fig. 1 shows a schematic circuit diagram of a cooling device 100 into which the cooling element 70 of the present invention can be inserted.

The device 100 for cooling long products, into which the cooling element of the present invention can be inserted, features a plurality of cooling elements 70. The cooling elements 70 may be arranged, for example, continuously along the material flow of the long product through the device 100. However, the present invention is not limited to such an embodiment. For example, the cooling elements 70 may also be arranged along several separate production lines in order to cool different long products.

In a cooling device 100 for cooling long products as depicted in fig. 1, the cooling device 100 defines a material flow of the long products. The device 100 features a coolant supply pipe 42 for supplying coolant and a plurality of cooling elements 70 connected to the coolant supply pipe 42 via respective individually adjustable control valves 90. The coolant flow rate of the cooling element 70 depends on the opening degree of the respective control valve 90, whereby a flexible distribution of the coolant flow rate along the material flow is achieved by adjusting the opening degree of the control valve 90.

The cooling elements 70 are each connected to the coolant supply pipe 42 via a control valve 90. Each control valve 90 is configured to continuously control the coolant flow rate fed into the cooling element 70 over its control range via the coolant supply pipe 42.

The embodiment describes three cooling elements 70 arranged consecutively in the direction of the material flow. However, the present invention is not limited thereto: first, the number of cooling elements 70 may vary: for example, an embodiment with seven cooling elements 70 has proven effective. Secondly, not all cooling elements 70 fed by the coolant supply pipe 42 have to be arranged in the same production line. In particular the coolant supply tube 42 may feed coolant to several production lines by arranging the cooling elements 70 in several different production lines for long products. In this case, distribution of the coolant supplied from the coolant supply pipe 42 on different production lines is carried out by adjusting the opening degree of the control valve 90.

The supply of coolant to the coolant supply tube 42 may be permitted and blocked by the latching valve 102. The latching valve may be a ball valve or another type of valve that alternately permits or blocks the volumetric flow of coolant.

The coolant pressure in the coolant supply pipe 42 may be measured by the pressure measuring device 104.

Using the pressure measurement device 106, the respective coolant pressure behind each control valve 90 may be measured. In this context, the term "rearward" of each control valve 90 refers to a position that is rearward, i.e., downstream, of the control valve 90 in the flow direction of the coolant. In the embodiment depicted in fig. 1, this position is between the control valve 90 and the respective cooling element 70. At the same time, however, other embodiments of the arrangement of the pressure measurement device 106 are possible. For example, the pressure measurement device 106 may be positioned inside the cooling element 70.

Thus, each pressure measuring device 106 measures the pressure of the coolant released by the cooling element 70 in the direction of the long product. A pressure measuring device 104 measures the pressure in the coolant supply pipe 42 in front of each control valve 90. The drop in pressure behind each control valve 90 can be determined by calculating the difference between the pressure measured by the pressure measuring device 104 and the pressure measured by the pressure measuring device 106. The pressure measured by the pressure measuring device 106 is related to the flow rate of the coolant released by the cooling element 70, which means that this flow rate can be determined from the pressure difference.

Thus, setting the opening degree of each individual control valve 90 individually allows adjusting the distribution of the coolant flow rate through the coolant supply pipe 42 onto the cooling element 70 at a given coolant flow rate. Thus, long products directed through the apparatus 100 along the material flow may be cooled in different sections of the apparatus 100 at different coolant flow rates. Along the material flow, the long product may be cooled only slightly in the first cooling element 70, e.g. due to the low coolant flow rate released by this first cooling element 70. Then, in the subsequent cooling element 70 along the material flow, the long product may undergo more intensive cooling due to the higher coolant flow rate released by this cooling element 70. The local fine tuning of the coolant flow rate in the apparatus 100 relative to the passing long product allows for the timed setting of the coolant flow rate as the long product moves along the material flow. Although in principle such settings may be estimated based on production parameters, it is preferred to provide means for separately measuring to determine the position of the long product in the apparatus, in order to determine the position of the long product, which allows for a finer adjustment of the temperature of the long product over time.

The variation of the fine adjustment temperature over time depends on the desired requirements of the finished product.

Fig. 2 shows a cross-sectional view of a cooling element 70 according to an embodiment of the invention.

In the embodiment of the cooling element 70 as depicted in fig. 2 for cooling the long product during processing, the circumferential direction is defined by the cooling element 70 such that the long product to be cooled passes through the cooling element substantially perpendicular to the circumferential direction.

The cross-sectional view in fig. 2 presents a view perpendicular to the material flow of the long product, which moves parallel to the longitudinal axis 214 and to the circumferential direction of the cooling element.

The cooling element 70 features a cooling line 202 for releasing coolant in the direction of the long product. The cooling line 202 features a first ring 208 and a second ring 210, the first ring 208 and the second ring 210 each spanning an entire circumference of the cooling element 70 about the material flow and the longitudinal axis 214, respectively. The rings 208, 210 constitute the nozzle 206 and are configured to apply coolant uniformly to the passing long product.

The rings 208, 210 are arranged consecutively. The nozzles 206 configured as flat spray nozzles are arranged alternately in the ring and in the circumferential direction, so that the nozzles 206 of the second ring 210 are arranged centrally in the circumferential direction, i.e. in an angular position between two nozzles 206 of the first ring 208. This design allows a particularly uniform application of the coolant to the surface of the long product.

Behind the cooling head 202, the cooling element 70 features an equalization zone 204 along the material flow. The equalization zone 204 features a discharge outlet 212 to quickly drain coolant from the rolled material to be cooled (correspondingly, the long product) and to facilitate temperature equalization between the core and the surface of the long product. The discharge outlet 212 may be shaped like a slit, as depicted, or in the form of a screen-like hole, for example.

REFERENCE LIST

42 coolant supply pipe

70 cooling element

90 control valve

100 device

102 lock valve

104 pressure measuring device

106 pressure measuring device

202 cooling head

204 equalization zone

206 nozzle

208 first ring

210 second ring

212 discharge outlet

214 longitudinal axis.

Claims (5)

1. A cooling element (70) for cooling long products along a material flow, characterized in that

The cooling element (70) is characterized by a plurality of nozzles for releasing coolant onto the long products, which nozzles are arranged circumferentially around the material flow,

the nozzles (206) are evenly spaced along the circumferential direction so that the coolant can be evenly released onto the long product and distributed throughout the circumferential direction.

2. The cooling element (70) according to claim 1, characterized in that the nozzles (206) are configured as spray nozzles arranged annularly in the circumferential direction.

3. Cooling element (70) according to claim 2, characterized in that the spray nozzle is configured as a flat spray nozzle.

4. A cooling element (70) according to any of claims 1-3, characterized in that the nozzles (206) are arranged in at least two consecutive rings (208, 210) along the material flow in order to allow uniform cooling of the entire circumference of the long product.

5. Cooling element (70) according to one of claims 1 to 3, characterized in that it comprises a cooling line (202) and an equalization zone (204), the cooling line (202) having a nozzle (206),

wherein the equalization zone (204) features a drain outlet (212) to drain coolant from the long product.

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