SU765626A1 - Gas-distributing plate - Google Patents

Description

: 54) GAS DISTRIBUTION PLATE

one

The invention relates to heat engineering, in particular, to designs of a device such as a gas jet cushion, and can be used in metallurgical and other industries.

A known furnace for heating a sheet metal on a gas cushion, where the sheet is supported and heated by jets emanating from the holes in the jet grille 1.; The spent gas forms a cross-flow directed to the edges of the sheet. This flow causes a deviation of the jets, i.e. The conditions of meeting the jet with the heat exchange surface change and, as a result, the heat transfer coefficient over the sheet surface decreases by 1.5 times, the heat transfer unevenness increases, thermal deformations occur, and the sheet stability decreases, since the distribution of static pressure across the width of the pillow is uneven.

Also known is the gas distribution plate (under the furnace) having openings 2.

The gas jet is created by a special organization.

Jet gas flow between the perforated plate and the part. The product is supported above the plate due to the dynamic effects

5 jets impacting its surface due to the overpressure between the part and the jet array. The direction of the flow of exhaust gas moving between the jet grille

10 and the product in the gas cushion of rectangular and square formulas in plan coincides with the axes of symmetry in; central area, in the areas adjacent to the edges of the sheet, the flow goes

.15 from a gas cushion at an angle to the main axis of symmetry. Moreover, by the measures of accumulation of the waste gas, the demolition of the jets increases, which leads to a decrease in the intensity of heat exchange.

20 on the surface, there is a significant non-uniformity.

The aim of the invention is to intensify heat exchange and improve the uniformity of the heat sink.

25

This is achieved by the fact that the plate is provided with protective visors of convex shape with an angle of coverage J3 of 160-180 °, installed from the axis of the holes of the plate at a distance of 0 С + 2Н tgof,

thirty

where I fT is the relative diameter J, the visor; - the relative diameter li of the holes in the plate; H — c- —relative height

visor;

- the angle of the jet;

D is the diameter of the visor;

h- height of the visor.

The drawing shows the proposed device, a General view.

The gas distribution plate is a perforated plate 1, on the surface of which protective visors 2 are installed. The protective visors have a convex profile and the end surface is rigidly fixed to the surface of the perforated plate.

When gas is applied to the stove 1, OTBepcTliH is hit by gas jets, hit the surface of the product, supply (discharge) to it (from it) heat and keep the product alive. The exhaust gas forms a cross flow. The protective visors 2 do not allow the cross-flow of the exhaust gas to deflect the jets, forming dead zones. Conditions of impact of the jet with the heat exchange surface and, consequently, the heat transfer coefficient at the center of the product and at its periphery is the same and has the maximum value, thereby achieving maximum intensity, high teloexchange uniformity, as well as the stability of the product on a gas cushion.

The jet heat exchange is greatly influenced by the process of turbulent displacement of the jet with the medium. Therefore, the profile of the visor does not close around the jet. The angle of coverage ranges from 160 to 180 °. The angle 160 is determined by the beginning of the zone of turbulization of the flow on the surface of the visor, the angle of 180 ° is determined by the yielding II of the jet displacement from the environment. The side curtains of the visor are flow turbulators, and the flow separation zone is a source of turbulent transverse pulsations that intensify the jet displacement with the environment, and therefore improves heat transfer on the surface of the product. . efficiency, exchange in devices like a gas jet pillow, but also contributes to the intensification of this process. The protective visor should not deform the jet flow, therefore the distance from the axis of the hole on which the visor is installed is determined by the angle of jet opening and is calculated by

 B D + 2 N. tg

where D g i. -, relative dian

meter visor;

DO- o

-dia and meter holes in the jet array;

M ji

- relative height

n visor; l

angle of the jet;

D

-diameter otzya hzti in the jet array;

n

- the distance between the jet grating and the surface of the product;

h, is the height of the visor.

ShksitLapna efficiency of jet heat exchange is achieved at DO 0.125-0, 5.

The jet angle is 7-10. Let's set the relative height of the visor. Then the relative diameter of the goat will be 125-5.856.

Claims (2)

Invention Formula A gas distribution plate, having openings, characterized in that, in order to intensify heat exchange and improve the uniformity of heat dissipation, it is equipped with convex-shaped transparent visors with an angle of coverage 160-180, installed from the axis of the plate openings at a distance of D p + 2 H-tgo (, B-0 where -diaT k meter visor; -relative dian meter holes in -L stove; AND -relative height n visor; d ( angle of the jet; D n - diameter of the visor; - the distance between the plate and fire; DO- diameter of holes in stove; h- height of the visor, Sources of information taken into account in the examination 1, USSR author's certificate 276134, cl. C 21 D 9/46, 1968, 2. USSR author's certificate 350844, cl. F 27 B 9/28, 1974.