UA55901A - Device for hydrojet removal of scale from blanks of rolling mill - Google Patents

Abstract

A device for hydrojet removal of scale from blanks of rolling mill contains nozzles mounted by their exits towards blank surface to be cleared, and by entrances they are connected to exit of pump station which contains two or more connected in parallel pumps and a pressure regulator, and also a control device containing a block for information input. A pressure regulator is manufactured as controlled by-pass valves with gating elements which number corresponds to the number of pumps. A block of pressure formation is additionally added to the control device. Entrances of gating elements are connected to entrances of by-pass valves, and exits are connected to an exit of pump station.

Description

The invention belongs to the field of metallurgy and can be used for hydrojet cleaning of scale, oxide film, slag, dirt and surface defects of various blanks on rolling mills, including slabs on hot rolling mills.

The well-known slag hydraulic crushing system of the company "5ZM5 - Zspibtapp -5ietad AS" (industry report of UNRS and rolling plant: "Technical possibilities and further improvement of technologies C5V", author

Wolfgang Rohde and Gunther Flemming. - Spec. exit from MPT. Ed. Stalleisen Dusseldorf. My. 19 (1996) pp. 13-14).

The known system includes spraying heads with nozzles connected to a hydraulic station, which contains pumps with adjustable water pressure of 30-32 MPa. A feature of this system is the small distance of the nozzles to the surface of the sheet with their increased number. Due to the relatively high pressure and the small distance of the nozzles to the surface, the quality of cleaning of the specified water hammer is quite high. However, constant pressure with various types of scale leads to increased consumption of electricity and water. The latter is also enhanced by a large number of nozzles.

There is also a known device for water jet cleaning of rolling mill blanks from scale (Application of the Federal Republic of Germany

Me3125146 from June 26, 1981, Bull. "Inventions in the USSR and abroad", Me13, 1983, p. 36) with a working pressure of 20.0-50.0 MPa and a suffocating beam that rotates and is equipped with nozzles, which allows it to repeatedly spray the roll with water streams. This device has the same disadvantages - high energy and water consumption.

The closest in terms of technical substance to the stated one is a device for water jet cleaning of rolling mill blanks from scale (A. Krol "Hydromechanical scale removal on wide-strip hot rolling mills", "Black metal!", March 2000, pp. 48-52, fig. 5), which contains nozzles installed with outputs to the surface of the workpiece to be cleaned, and the inputs are connected to the output of the pumping station, which includes two or more pumps connected in parallel and a pressure regulator, as well as a control device that contains an information input unit , the input is connected to the workpiece presence sensor. In this device, the pressure regulator is made in the form of one adjustable valve with an electropneumatic regulator, and the output of the latter is connected to the input of the valve adjustment. In addition, the pumps are triple-plunger with push-off suction valves. The pressure regulator allows you to set the specified pressure in advance and maintain its constant level when cleaning the workpieces. Thanks to the squeezing of the pump valves in the absence of a workpiece, the pumps are unloaded from the pressure, as a result of which this device is more economical compared to the previous ones.

The disadvantages of the known device are as follows: there is no possibility of controlling the pressure during the operation of the rolling mill, as a result of which, with less strong types of scale of the workpieces, the set pressure is excessive, therefore there is an increased consumption of electricity and water; unloading pumps from pressure by squeezing the suction valves is structurally complex with low reliability; with the indicated design of the pressure regulator and unloading of the pumps, it is impossible to unload one pump or a part of the pumps while the rest of the pumps are working, which is necessary, for example, for cleaning weak scale at the pressure that provides the unloaded remaining pumps. This also leads to high energy and water consumption and, in addition, to a low resource, because all pumps work continuously under pressure, and the pressure value is set high according to the strongest type of scale.

The invention solves the problem of improving the device for hydrojet cleaning from scale of rolling mill blanks by such improvement of the pressure regulator and the control device, which ensures economical unloading of pumps, reduction of working pressure, which ensures low consumption of energy and water with a high resource of the equipment, simplifying the design and increasing reliability work

The task is solved by the fact that in the device for hydrojet cleaning of rolling mill blanks from scale, which contains nozzles installed with outlets to the surface of the billet being cleaned, and the inlets are connected to the outlet of the pumping station, which contains two or more pumps connected in parallel and a pressure regulator, as well as a control device containing an information input unit, the input is connected to a sensor for the presence of a workpiece, according to the proposed invention, the pressure regulator is made in the form of controlled bypass valves with shut-off elements according to the number of pumps, and an additional input is added to the control device pressure forming unit, the input is connected to the information input unit, and the outputs are connected to the corresponding control inputs of the bypass valves with shut-off elements, and the inputs of the shut-off elements are combined with the inputs of the bypass valves, and the outputs are connected to the output of the pumping station.

At the same time, the closing element is made in the form of a non-return valve, the input of which is combined with the input of the bypass valve, and the output is connected to the output of the pumping station.

The essence of the invention is as follows. In order to obtain high-quality rolled products, it is necessary to completely clean the surface of the workpiece. So, for example, the incomplete extraction of furnace slag in front of the cage leads to its pressing by rollers into the body of the workpiece and, accordingly, the lack of rolling due to the so-called rolled slag.

Physico-mechanical parameters and scale strength of slabs in hot rolling conditions are significantly different, and for their removal by water jets, different pressures are required at the entrance of the nozzles, since the hydromechanical force of the water jet on the surface of the workpiece depends on the value of this pressure. So, for example, if the heating furnace works in the oxidizing mode, then we get a thick, dry scale that is easily removed, which allows us to use a relatively low water pressure in the nozzles, that is, much lower than the nominal pressure of the pumping station. At the same time, even in the oxidation mode, high-alloy and low-carbon steels produce the so-called sticky scale, which has high strength and requires the use of high pressure. Nowadays, rolling mills use hydraulic scum removal systems, which have a constant pre-set pressure in the process of cleaning the workpieces, which is chosen in such a way as to ensure the cleaning of the workpiece from the strongest scum. In the case when the scum is less strong, it is lost by the same pressure, which in this case is excessive. As is well known (see T. M. Bashta "Obyemnse naso's! y hydravlicheskie dynusti hidrosistem", M., "Mashinostroenie", 1974, pp. 17-19), the energy consumption of the pump is directly proportional to the pressure at its outlet, and the flow of water through the nozzles also depend on this pressure. In this regard, in the case of cleaning weak scale, there is an excess consumption of energy and water. The consequences of this are the high rental cost and low environmental performance.

Saving energy and water consumption, as well as increasing the resource of the equipment, simplifying its design and increasing reliability are achieved by combining the functions of the pressure regulator not only to control the pressure at the outlet of the pumping station, but also to cut off one or more pumps from the outlet of the pumping station with their simultaneous unloading from pressure This set of functions of the pressure regulator in the proposed device is also possible thanks to the pressure forming unit introduced into the device, which sets the minimum pressure levels required for different types of scale at the control inputs of the corresponding bypass valves with shut-off elements, at which cleaning of the workpieces is carried out economically in terms of energy and water consumption. At the same time, if the pressure level required for a specific type of scum is provided without one or more pumps, the pressure forming unit sets zero pressure levels at the inputs of the corresponding bypass valves with shut-off elements, i.e. it relieves the specified pumps from pressure. In the absence of a workpiece, all pumps are relieved of pressure in the same way. This, along with the specified control of the pressure level depending on the type of scale, increases the resource of the equipment, and the combination of the pump unloading functions in the pressure regulator made it possible to eliminate the mechanism of suction valve imprinting, which simplifies the design and increases reliability. This effect is enhanced when the shut-off element is made in the form of a non-return valve, the input of which is combined with the input of the bypass valve, and the output is connected to the output of the pumping station, because when the pump is unloaded, it is cut off from the output of the pumping station thanks to the non-return valve without a separate control signal and drive locking element.

The essence of the invention is explained by the drawings, which show: Fig. 1 - a general view of the device for hydrojet cleaning from scale of rolling mill blanks; Fig. 2 - a closing element made in the form of a non-return valve. The device (see Fig. 1) contains nozzles 1, installed on the collector with outputs to the surface of the workpiece 2, which is cleaned, and the inputs are connected to the output of the pump station, which contains two or more pumps 3-1 connected in parallel... 3 - n and the pressure regulator 4, as well as the control device 5, which includes the information input unit 6, the input is connected to the sensor 7 of the presence of the workpiece. The pressure regulator is made in the form of controlled bypass valves 8 - 1... 8 - p with closing elements 9 - 1... 9 - p according to the number of pumps, and a pressure generating unit 10 is additionally introduced to the control device, the input is connected to the unit 6 information input, and the outputs - with the corresponding control inputs of the bypass valves with shut-off elements, and the inputs of the shut-off elements are combined with the inputs of the bypass valves, and the outputs are connected to the output of the pumping station. At the same time, all elements of the pressure regulator - bypass valves and shut-off elements - can be controlled. The pressure forming unit can be made in the form of several - by the number of pumps - electrically controlled pneumatic pressure transmitters, the pneumatic outputs of which are connected to the corresponding control inputs of the bypass valves with shut-off elements. It is also possible to implement it in the form of electrically controlled hydraulic pressure setters.

The closing element can be made in the form of a non-return valve 11 (Fig. 2), the input of which is combined with the input of the bypass valve 8, and the output is connected to the output of the pumping station. In this version of the pressure regulator, only the bypass valve is controlled.

The device works as follows. Water under low pressure, for example, from the water main is supplied to the inlet of pumps Z - 1... Z - n (Fig. 1) and further through the pressure regulator 4 of each pump - to the outlet of the pumping station and to the inlet of the collector with nozzles 1. the absence of workpiece 2 and, accordingly, the signal of the sensor 7 of the presence of the workpiece at the output of the unit 6 of the information input and the unit 10 of the pressure formation of the control device 5, signal levels corresponding to the zero pressure of all pumps 3 are set. At the same time, the bypass valves 8 - 1... 8 - p unload the pumps to the drain, and the closing elements 9 - 1... 9 - p cut them off from the pump station outlet. Accordingly, there is no pressure at the inlets of nozzles 1 and water flow through them. When feeding the workpiece 2 along the roller conveyor to the nozzle 1, the sensor 7 of the presence of the workpiece is activated, the signal of which is fed to the input of the information input unit 6. At the same time, the input of this unit receives information, for example, from the information support system and the methodical furnace control system about the parameters of the workpiece, including the type and strength of the scale. Such information from the information input unit 6 enters the input of the pressure generation unit 10, which sets at its outputs such signal levels that ensure the optimal pressure at the output of the pumping station, that is, the minimum necessary pressure that ensures high-quality cleaning of workpieces from scale at the lowest possible consumption energy and water. These signals enter the control inputs of the pressure regulator 4, which, with the help of bypass valves 8 - 1... 8 - n, sets the specified optimal pressure at the outlet of the pumping station and, accordingly, at the inlet of the nozzles 1, which form water jets that provide cleaning from workpiece scum in the optimal mode. At the same time, the output signals of the unit 10 of pressure formation may not have the same levels. In particular, if the output pressure level of the pumping station formed by this block can be ensured, for example, without one of the pumps, then the corresponding output signal of the block 10 will have a value in which any of the pumps will be unloaded by the bypass valve for draining, and the pump output is turned off with the help of a closing element from the output of the pumping station. In this case, the nozzles will be fed by the remaining group of pumps at the specified optimal pressure level, and the bypass valves of these pumps can be controlled by different signal levels of the unit 10 of pressure formation. This ensures, in particular, an increase in the resource of pumps and bypass valves. In the case of the closing element in the form of a non-return valve 11 (Fig. 2), when the pump is unloaded from the pressure using the bypass valve 8, the non-return valve 11 is automatically closed by the pressure from the pump station outlet and cuts off the output of this pump. After complete cleaning of the scale, the workpiece 2 comes out from under the nozzle 1, the signal from the output of the sensor 7 of the presence of the workpiece disappears, and the device returns to its initial state.

Thus, the proposed device provides the minimum possible energy consumption during hydrojet cleaning of rolling mill blanks from scale with economical water consumption. At the same time, an increase in the resource and reliability of the equipment is also achieved due to the reduction of the load.

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Claims (2)

1. A device for hydrojet cleaning of rolling mill blanks from scale, containing nozzles installed with outlets to the surface of the billet to be cleaned, and the inlets connected to the outlet of the pumping station, which contains two or more pumps connected in parallel and a pressure regulator, and also a control device containing an information input unit, the input is connected to a sensor for the presence of a workpiece, which is distinguished by the fact that the pressure regulator is made in the form of controlled bypass valves with shut-off elements according to the number of pumps, and a pressure forming unit is additionally introduced to the control device, the input connected to the information input unit, and the outputs - to the corresponding control inputs of the bypass valves with shut-off elements, and the inputs of the shut-off elements are combined with the inputs of the bypass valves, and the outputs are connected to the output of the pumping station. 2. The device according to point I, which differs in that the closing element is made in the form of a non-return valve, the input of which is combined with the input of the bypass valve, and the output is connected to the output of the pumping station.