COILING MANDREL AND RELATIVE PROCEDURE FOR MONITORING THE CONDITION THEREOF

Abstract

The present invention refers to a cooling control system of a coiling mandrel (102; 202; 302; 402; 502; 602) for metal products which comprises: an internal shaft (108; 308) with a plurality of sectors (109); an external drum which as a whole contains coaxially said internal shaft and which is circumferentially subdivided into a plurality of segments (104) arranged in a direct or indirect coupling connection with said sectors; and an internal and/or external cooling system of the mandrel The segments are movable in a radial direction with respect to said internal shaft through an axial movement of the latter, causing the consequent radial expansion or collapse of the drum. The mandrel is further provided with a group of temperature detection sensors (130, 132, 134, 136; 234, 236; 332, 336; 43N; 53N; 63N; 3N). A method for monitoring and adjusting the temperature of a coiling mandrel is also described.

Claims

1. A cooling control system of a coiling mandrel for metal products originating from a hot rolling mill plant comprising: a coiling mandrel which comprises an internal shaft with a plurality of sectors; an external drum which as a whole contains coaxially said internal shaft and which is circumferentially subdivided into a plurality of segments arranged in a direct or indirect coupling connection with said sectors, wherein the indirect coupling connection is realized by wedges coupled to anyone of said sectors and interposed between said segments and said sectors; an internal and/or external cooling system of the mandrel; wherein said segments are movable in a radial direction with respect to said internal shaft by an axial movement of the latter, subsequently to the internal shaft, causing the consequent radial expansion or collapse of the drum; and wherein said mandrel is provided with a group of temperature detection sensors; and a control unit adapted to:  receive temperature data measured in the mandrel, and provided with an algorithm which:  compares said data with temperature nominal values,  increases, reduces or maintains constant the flow of the cooling liquid based on the difference determined between the measured value of the temperature and the target nominal value of the temperature.

2. The cooling control system of a coiling mandrel according to claim 1, further comprising: electronics for managing said sensors; and an electric power supply unit to feed the electronics and the temperature sensors.

3. The cooling control system of a coiling mandrel according to claim 2, further comprising: (g) a telecommunicating system to permit the transmission of the measured temperature data to an external receiver.

4. The cooling control system of a coiling mandrel according to claim 1, wherein the temperature measuring sensors are arranged in positions selected from the drum segments, the wedges, if present, the sectors of the internal shaft, the free spaces inside the mandrel and the external surface of the drum and/or combinations thereof.

5. The cooling control system of a coiling mandrel according to claim 4, wherein the temperature measuring sensors are predominantly arranged in the free spaces inside the mandrel.

6. The cooling control system of a coiling mandrel according to claim 2, wherein said electric power supply is selected from flywheel masses inserted at the rotational axis of the mandrel wherein the rotation of the shaft puts in rotation the flywheel mass which permits through an alternator the generation of an electromotive force, batteries, permanent magnets, Peltier elements.

7. The cooling control system of a coiling mandrel according to claim 1, wherein the temperature measuring sensors are selected from junction thermocouples, infrared thermocouples, fibre optic temperature sensors and infrared sensors.

8. The cooling control system of a coiling mandrel according to claim 2, wherein said electronics are configured such that said electronics comprise: an A/D converter to converting the data measured by the sensors from analog signals to digital signals; and an antenna to transmit the digital signals to an external reader, wherein the electronics are self-powering, and self-powering is accomplished from an action of a flywheel mass oriented in the rotational axis of the mandrel to server as an inertial electric generator or self-powering is provided from a battery.

9. A process for monitoring and adjusting the temperature of a coiling mandrel by a cooling control which comprises the following steps: making available a cooling control system for a coiling mandrel according to claim 1; coiling a product coming from a hot rolling mill around said mandrel and simultaneous internal cooling of the mandrel; measuring, using said temperature measuring sensors with a desired frequency, the temperature at various measurement points of the mandrel; data processing and sending to a control unit; comparing the measured data (T.sub.meas) with nominal data (T.sub.n) stored in the control unit; and increasing the flow of the cooling liquid where the measured value is greater than the nominal value, reducing the flow of the cooling liquid where the measured value is lower than the nominal value, and maintaining the flow of the cooling liquid where the measured value is equal to the nominal value.

10. The cooling control system of a coiling mandrel, according to claim 9, wherein the battery is a backup battery loaded by the action of said inertial generator.

Description

DESCRIPTION OF PREFERRED EMBODIMENTS

[0054] FIG. 1 shows a longitudinal section of a coiling mandrel according to the state of the art.

[0055] FIG. 2 shows a cross-section along the line II-II of FIG. 1 of the coiling mandrel according to the state of the art.

[0056] FIG. 3 shows the insertion of a coiling mandrel in a hot rolling line.

[0057] FIG. 4 shows a longitudinal section of a coiling mandrel according to the invention.

[0058] FIG. 5 shows in a sketched form a coiling mandrel according to the invention with a first exemplary embodiment of the configuration of the sensors inside the mandrel.

[0059] FIG. 6 shows in a sketched form a coiling mandrel according to the invention with a second exemplary embodiment of the configuration of the sensors inside the mandrel.

[0060] FIG. 7 shows a coiling mandrel according to the invention with a first exemplary embodiment of the power supply of the electronics.

[0061] FIG. 8 shows a coiling mandrel according to the invention with a second exemplary embodiment of the power supply of the electronics.

[0062] FIG. 9 shows a coiling mandrel according to the invention with a third exemplary embodiment of the power supply of the electronics.

[0063] FIG. 10 shows in a block diagram an exemplary embodiment for the electronics installed in a mandrel according to the invention.

[0064] FIG. 11 shows a feedback scheme of an exemplary embodiment of a method for governing the internal and external cooling of a coiling mandrel according to the invention.

[0065] FIG. 1 shows a longitudinal section of a coiling mandrel according to the state of the art. The traditional mandrels 2 (see for example U.S. Pat. No. 3,658,274) are made by means of a system of radially expandable segments 4 thanks to wedges 6 coupled to the action of a conical shaft 8 moved axially along the arrow a with respect to the mandrel so as to increase or decrease the mutual distance between the segments and the shaft. The mandrel 2 is supported by means of bearings 10 supported by a frame 12. FIG. 1 shows the sliding ratio created between the shaft and wedges/segments (arrow a).

[0066] FIG. 2 shows in a cross-section along the line II-II of FIG. 1 a coiling mandrel to the state of the art, which allows to understand how the mandrel 2 can expand or collapse according to the different steps of the coiling process. The area A shows the fully expanded segment 4, the area B shows an intermediate expansion of the segment 4, while the area C shows the segment 4 in the completely collapsed version. The shaping 14 represents the end of stroke for the expansion of the segments 4.

[0067] The coiling starts with the partially collapsed mandrel 2, therefore with a diameter close to the minimum and a reduced rotation speed. A strip (not shown) is driven by suitable known deflectors (not shown) around the mandrel 2 until the formation of at least one complete turn around it, so that the head of the strip is stuck and held by the following strip. Once this has occurred, the coiling speed is increased and the mandrel 2 begins the step of progressive expansion of its diameter: in this way the internal friction between the strip and the mandrel 2 gradually increases in order to avoid slippage between the coiled layers and thus increase the quality of the coiling. The coiling step lasts about 3 minutes with the strip temperature at 600-700° C.

[0068] FIG. 3 shows an example of a coiling mandrel in a hot rolling line. The mandrels 2 which operate on the downcoilers are used for coiling the rolled strip 16 in a hot rolling line. A series of mill stands 18 provide a progressive thinning of the thickness of the strip 16, which then passes on a roller path 20 and is cooled by jets of water 22 at a temperature suitable for coiling (about 600-700° C.).

[0069] The product is then sent through conveyor systems and bridles 24, suitable for keeping the strip 16 in traction, to the coiling area in a coiling mandrel 2, wherein the latter begins to coil the rolled product 16 on itself until it reaches the limit weight at which a known shear (not shown) intervenes separating the coil formed from the rest of the strip 16 upstream for its evacuation from the line.

[0070] FIG. 4 shows a longitudinal section of a coiling mandrel 102 according to the invention. The mandrel 102 is provided with a shaft 108 with various conical sectors 109, interfacing with wedges 106, so as to permit the mutual approach/departure between the different segments 104 of the mandrel 102. The structure of the mandrel essentially corresponds to that of the mandrel disclosed in U.S. Pat. No. 3,658,274. Further constructional details or possible variants of the mandrel are widely known and therefore do not require a more detailed disclosure. The inventive concept of thermal control of the mandrel is applicable to the most varied embodiments of mandrels of the type defined in the first claim.

[0071] The black points distributed both in the structure of the mandrel 102, and in the free spaces created between the different components, symbolize the measurement points of the temperature sensors (130 the sensors in the segments, 132 the sensors in the wedges, 134 the sensors in the conical sectors of the shaft and 136 the sensors in the free spaces) which are installed to measure the thermal gradient of the area. The electronics 142 deals with the power supply of the sensors 130, 132, 134, 136 and of the data accumulation which are sent through the antenna 140 to an external processing unit (not shown) which compares them with threshold or nominal values so as to actively drive the cooling. In a preferred variant, the electronics 142 is housed in the area supporting the rotation of the mandrel on the operator side.

[0072] By way of example, these sensors 130, 132, 134, 136 can be junction thermocouples, infrared thermocouples, optic fibre temperature sensors, infrared sensors.

[0073] FIG. 5 shows in a sketched form a coiling mandrel 202 according to the invention with a first exemplary embodiment of the configuration of the sensors 234, 236 inside the mandrel 202, and precisely in the conical sectors of the shaft and in the free spaces. The wiring 250 connects the sensors 234, 236, the electronics 242 and the antenna 240.

[0074] FIG. 6 shows in a sketched form a coiling mandrel 302 with shaft 308 and wedges 306 according to the invention with a second exemplary embodiment of the configuration of the sensors inside the mandrel. Here it is possible to note sensors 332 inside the wedges 306 and sensors 336 in the free spaces. A wiring 350 connects the sensors 332, 336, the electronics 342 and the antenna 340.

[0075] FIG. 7 shows a coiling mandrel 402 with sensors 43N (N stands for 0, 2, 4, 6 to indicate that the position of the sensor does not matter here, but that the types of power supply represented apply to all imaginable positions of the sensors) with a first exemplary embodiment of the power supply of the electronics which is represented here by permanent magnets 460. In addition, it is possible to note wiring 450, electronics 442 and antenna 440.

[0076] FIG. 8 shows a coiling mandrel 502 according to the invention with sensors 53N (N stands for 0, 2, 4, 6 to indicate that the position of the sensor does not matter here, but that the types of power supply represented apply to all imaginable positions of the sensors) with a second exemplary embodiment of the power supply of the electronics which is represented here by a plurality of Peltier elements 570. In addition, it is possible to note wiring 550, electronics 542 and antenna 540. The wiring 550 also connects the Peltier elements 570 to the electronics 542.

[0077] FIG. 9 shows a coiling mandrel 602 according to the invention with sensors 63N (N stands for 0, 2, 4, 6 to indicate that the position of the sensor does not matter here, but that the types of power supply represented apply to all imaginable positions of the sensors) with a third exemplary embodiment of the power supply of the electronics which is represented here by a contactless device 680 comprising power supply with current and the signal transmission. The wiring is referred with 650.

[0078] FIG. 10 shows in a block diagram an exemplary embodiment for the electronics installed in a mandrel according to the invention for the power supply of the sensors.

[0079] The sensors (e.g. thermocouples) detect an analog signal which is converted into digital and stored in a memory and sent in the form of data packages to an external reader by means of the antenna. The sensors 3N of temperature T1, T2, T3, T4, T5 send analog signals to the A/D converter 19 which converts them into digital signals which through a temperature recording and analysis electronics 17 and a receiver/transmitter module 15 are processed and sent to an external control unit (not represented) through the antenna 40. These disclosed elements constitute an analysis and communication module, which is powered by an electric power supply module composed of a battery 13, a battery charging module 11 and an energy converter 7 powered by an inertial generator 5 with connections and operations well known in the art. These electronic components can be powered in different ways. For example, it is possible to arrange a battery, vice versa the preferred solution is the ability of the system to self-power without the aid of external power supply sources but through the action of a flywheel mass inserted in the rotational axis of the mandrel and which behaves as an alternator and called an inertial electric generator.

[0080] Depending on the operating conditions, a second solution provides for the use of a backup battery which is charged by the energy made available by this inertial generator.

[0081] Finally, FIG. 11 shows a feedback scheme of an exemplary embodiment of a method for governing the internal and external cooling of a coiling mandrel according to the invention. At the beginning 21 there is a heat source with a certain temperature which is measured 23 by a sensor. The measured temperature T.sub.meas is compared 25 with a target temperature nominal value T.sub.n corresponding to a temperature at which the surface should remain. If the values coincide 29, the cooling system receives the message 31 to keep the cooling flow constant. If the values do not correspond 27, 33 there can be two situations wherein T.sub.meas≠T.sub.n, and precisely the case 37 wherein T.sub.meas<T.sub.n and the case 35 wherein T.sub.meas>T.sub.n. In the first case 37, the cooling system receives the command to reduce the cooling flow 41, in the second case 35, it receives the command to increase the cooling flow. Subsequently 43 the process continues with a new temperature measurement 23, a following comparison of the temperature with respect to the target one and a subsequent cooling control.

[0082] In the executive step, it will be possible to make non-disclosed further modifications or executive variants to the coiling mandrel for products originating from hot rolling, to the cooling control system of the coiling mandrel and to the procedure for controlling and adjusting the temperature of the coiling mandrel by controlling its cooling, object of the invention. If such modifications or such variants should fall within the scope of the following claims, they should all be considered protected by the present patent.