RU1768341C - Header for cooling rolled products - Google Patents

Abstract

SUMMARY OF THE INVENTION: the collector comprises a filling container with a slotted nozzle installed in its lower part along the entire length, formed by two plates inclined to each other at an angle of 10-90 °, and a movable element for regulating the flow of coolant located inside the nozzle, connected to the drive of its reciprocating movement, made in the form of a wedge, with the sharp end directed towards the exit slit for the entire length of the nozzle. Inside the collector, on the upper surface of the wedge, for its entire length, an additional capacity is installed, for example a pipe, through holes are made in the wedge connected to the additional capacity. Compressed air or water may be supplied to the additional vessel to implement various rolling cooling schemes. 2 ill.

Description

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WITH

The invention relates to rolling production, in particular to devices for cooling rolled products during various heat treatment processes.

The purpose of the invention is the expansion of technological capabilities by increasing the number of implemented methods of supplying a cooler for hire and expanding the range of regulation of coolant flow.

Figure 1 shows the proposed collector, General view; figure 2 is a section aa in figure 1.

The collector for cooling the rolling stock contains a filling tank 1, in the lower part of which are mounted mirror-symmetrically two converging at an angle of the plate 2, forming a slotted nozzle with a width

slots a (Fig. 2) along the entire length of the tank 1. The collector is equipped with a cooler flow control device made in the form of a wedge 3 mounted with the possibility of reciprocating movements in the direction of coolant flow from the drive (for example, a hydraulic cylinder) 4 and rod 5, rigidly associated with the wedge 3. The wedge 3 is made equal in length to the length of the slit nozzle and divides it into two dispensing slots 6 of varying width, which are created on both sides of the wedge 3 between its forming surfaces 7 and the edges of the plates 2 of the slit nozzle, the total e cross section equal jets flowing a-ai (Figure 2).

The flow rate of the cooler from the tank 1 is controlled by changing the cross section of the dispensing slots 6 at

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00

with

reciprocating wedge 3 drive 4.

In order to increase the number of chiller supply schemes for the rolled steel being processed and the range of regulation of the coolant flow rate inside the collector (tank 1), an additional tank (pipe 9) is installed on the upper surface of the wedge 3 along its entire length, and the vertical axis in both the wedge 3 and the symmetrical axis - end-to-end reliably with respect to this element; Version 8c with d. The distance between the centers / longitudinal lines of the holes is tf, and the sum b + d is less than the gap width a. The holes 8 are arranged with a pitch h equal to 2-20 of the diameter d. Either cooling liquid or, for example, air or another gas can be supplied to cavities I and II (Fig. 2).

The proposed device makes it possible to realize four schemes for supplying a cooler to the rolled steel: a flat jet, a turbulized film, a water-air mixture, and round jets. This provides the widest range of regulation of the flow rate of cooling components,

Scheme I (flat jet). Water is supplied to cavity I, and nothing is supplied to cavity II. In this case, we obtain a flat film of water, known from the prototype. Water flow rate is regulated by changing the cross-sectional area of the dispensing slots by moving the wedge 3 or by changing the pressure of the water in the reservoir. The flow rate of water flowing from the collector is calculated by the formula

Q and a)

2d R

where g is the acceleration of gravity, g 9.8 m / s2;

/ and - coefficient of water flow;

(L is the cross-sectional area of the dispensing slots, m2;

P - water pressure in the collector, kg / m;

p is the density of the coolant, kg / m.

The angle of inclination of the plates forming the slot nozzle is selected within 10-90 °, while the wedge angle is equal to or 1-40 ° less than the angle of inclination of the plates. Depending on the angle of inclination of the plates, the angle of the wedge is such that the conicity angle of the formed slot nozzles is less than 50 ° to ensure continuity of the jet. If the angle of the wedge is equal to the angle of inclination of the plates, the coolant flows out from the dispensing slots and closes

5 10 15

0 5

0 5

0

5

0 5

the end of the wedge, forms a continuous inextricable flat stream. With increasing water pressure in the reservoir, increased turbulence of the flows and a discontinuity in the flat flow are observed. If the wedge angle is 1-40 ° less than the angle of inclination of the plates, then the coolant flows merge into one stream at a smaller angle and their interaction does not violate the continuity of the flat stream with increasing water pressure in the reservoir.

The slit nozzle of the proposed collector is cleaned of precipitating coolant impurities by purging the collector with water and air while periodically lowering and raising the movable element.

Scope I of the cooler supply circuit:

1) cooling of plate in sections of intense heat removal;

2) cooling the strip before winding. Example (according to Scheme I). With accelerated

when cooling sheets of steel 10KHSND after normalization heating by technology, it is required to reduce the temperature of the sheet from 910 to 650 ° C with a cooling rate of 25 ° C / s. Sheet width 2400 mm, thickness 12-30 mm. The collector has the parameters: Hydraulic diameter, mm 150 Width of the nozzle slit, mm20

Slot length of nozzle, mm 2400

The angle of inclination of the plates, degree 50 The angle of the wedge of the movable element, degree 25

When cooling sheets of 12 mm thickness, the water flow rate per collector is 50 m3 / h at a water pressure of 0.05 MPa. According to the above formula, the total width of the dispensing slots is 2.0 mm. By moving the wedge, a slit width of 2.0 mm is set. The water entering the collector is divided by the wedge into two streams and, flowing out from the dispensing slots, is reconnected into one stream and then falls onto a sheet in the form of a uniform flat film.

For a sheet 30 mm thick at a water pressure of 0.1 MPa and a water flow rate of 120 m3 / h, the estimated nozzle slot width is 3.4 mm. The readjustment is carried out by moving the wedge gate valve up.

Scheme II (round jets). In this case, water is supplied to the cavity II, and nothing is supplied to the cavity I. The water flow rate is calculated as in Scheme I, however, the cooling uniformity is worse, the flow rate can only be controlled by changing the water pressure in the collector. The distance between the centers of the holes in

the longitudinal direction is taken equal to 2-20 of their diameters, because closer proximity does not make sense due to the mutual flow of adjacent water jets, and a step greater than 20 diameters sharply worsens the uniformity of cooling.

Scheme III (turbulized film). Water is supplied to cavity I, air to cavity II. In this case, a water-air mixture is formed in which the water / air ratio is regulated over a wide range by moving the wedge. Scheme II allows one to control the cooling intensity over a very wide range from a turbulized water film at low air flow rates with a heat removal efficiency similar to that of a water film according to Scheme I, but with the saving of water to water mist at minimum water consumption with a cooling rate close to air, and also provide flows with intermediate cooling rates.

Scope of the scheme III:

1) cooling the strips after coating;

2) cooling of thin strips and sheets;

3) cooling the plate in sections of reduced cooling intensity. In the zone of increased cooling intensity according to Scheme I, the surface temperature of the rolled metal quickly decreases to 100 ° C, after which the convective cooling mode sets in, and the heat removal process is determined not by the increased flow rate of the cooler, but by internal thermal conductivity. After cooling in a section of increased intensity to tn 100 ° C with a heat flux q 3-4 mW / m, which is achieved at specific flows W 70-100 m / h-m, it is advisable to switch to cooling with q 1-1 to save the chiller 5 mW / m, which is achieved at W 10-30m3 / h-m2;

4) cooling of massive plates and billets, sheets of high alloy steel.

High-intensity cooling of such products leads to an increase in thermal stresses and the formation of cracks and other defects. Water-air cooling provides a wide range of cooling rates for the surface; therefore, it is possible to replace quenching in oil and various quenching media with cheaper and environmentally friendly cooling.

Scheme IV (water-air mixture). Air is supplied to cavity I, water to cavity II. The air flow rate, and therefore the water / air ratio, is controlled in this case by moving the wedge. The scheme is applicable for cooling sheet metal with significant water savings at the same heat sink rate.

The proposed collector makes it possible to implement four cooling schemes for rolled products, due to which the range of regulation of the flow rate of coolant is significantly expanded, and the range of chilled rolled products is greatly expanded. The collector is simple in design and reliable in operation.

Claims (1)

SUMMARY OF THE INVENTION A collector for cooling a rolling stock, comprising a filling container with a lower portion installed along its entire length a slit nozzle formed by two plates inclined to each other at an angle of 10-90 °, and located inside of the plate on its entire length, the regulating body connected to the drive of its reciprocating movement, made in the form of a wedge, with the sharp end directed towards the exit nozzle slots, characterized in that, in order to increase the number of implemented methods for supplying a cooler for hire and to expand the range for regulating the flow of coolant, it is equipped with an inside mounted collector on the upper surface to ins on its entire length with an additional tank, and the wedge has through holes connected to an additional tank. / 1 .Ј f O G 1 GTS1 | SH1GISCH1 -dy-f- -F- -f- -f -f- -O- -O- -F- -f-- -6L 4 $ 3 9 , -. tfto /