SU1195166A1 - Heat insulation of bottom tubes - Google Patents

Abstract

HEAT INSULATION OF GRADE PIPES containing refractory cylindrical blocks covering the pipe symmetrically, having thicknesses in the upper part and grooves for highlighting them on the edges of the pipe, characterized in that, in order to increase insulation resistance, the outer surface of each block is made with a radius of 1.82 -2.85 of the pipe radius, and the inner surface with a radius of 1.0-1.37 of the pipe radius, while the axes of the indicated surfaces of the blocks are located eccentrically at a distance of 0.5-0.6 of the pipe radius. (L coed 05 O5

Description

The invention relates to devices for transporting metal when it is heated in furnaces and can be used in the metallurgical and other sectors of the industry.

The aim of the invention is to increase the insulation resistance of the bottom tubes.

This design of the insulation segments causes the center of gravity of the suspended segment, in contrast to the known, to be positioned in such a way that the steep angle from the force of gravity will press the segment against the bottom tube, which will increase the stability of the segment relative to the attachment point and unload the segment at the slot. In addition, this self-clamping insulation to the bottom tube allows the segment to be hung on the pipe edge with gaps between the bottom pipe, its edges and the segment itself, which removes the additional stresses that occur in the segment during installation (due to the inevitable inaccuracies of welding of the fins to the pipes) and when moving the blanks through the pipes (due to the vibration of the pipe).

The drawing shows the insulation design of the bottom pipes, a general view.

Insulation consists of 1 refractory blocks 2 suspended from the bottom tube with slots 3 in which metal bars enter. pa 4. Refractory blocks are made in the form of identical segments thickened to the top with a total angle of coverage of the bottom tube 270 °

The segments are hung freely, without mutual engagement and with gaps between the surfaces of the segment and the bottom tube 1 (equal to b), as well as the ribs 4 of the tube and the groove 3 of the segment.

In order to prevent the metal deposits falling from the metal scale into the gap 6, as well as to protect the refractory segments from the mechanical impact of the billets advanced along the reiter 5, there is a gap between the visor 6. There is a gap between the shield 6 and the refractory block 2. Between the visor 6 and the rider 5, the insulation is made in the form of a refractory coating 7 reinforced with metal rods 8 welded to the pipe.

The upper surface of the segment, not covered with a visor, made in the form of a bevel under. angle of 30 ° to the horizon. This bevel angle is sufficient for the scale to crumble from the upper surface of the segment.

The pipe 1 itself and the fins 4 before being attached to them of refractory blocks 2 can be pre-coated with a layer of refractory fibrous material (kaolin wool), which will increase the thermal insulation properties of the insulation and the durability of the fins.

When moving the workpieces along the bottom 5 of the bottom tube 1, scale enters the upper part of the insulation of the bottom tube 1, which is then poured over the furnace along the beveled surface of the segment. Mechanical effects that occur when advancing the workpieces are perceived by protective visors and metal rods welded to the upper part of the bottom tube 1. The torque generated by the gravity of the segment P with shoulder h presses the segment to the bottom tube 1. The segments fit the tube tightly 1, the heat insulating fibrous material (if present) is pressed against the pipe, thereby protecting it from destruction and crumbling. When moving the workpieces, the tube vibrates. The destructive effect of vibration on the segments is practically eliminated by the existing gaps between the bottom tube 1, its ribs 4 and the segments themselves.

Refractory blocks have been developed for the whole range of diameters of the bottom pipes (from 80 to 220 mm) used in industrial furnaces.

Over the entire range of bottom pipes, to ensure reliable suspension, the segment groove is chosen as low as possible (according to the condition of durability of the rib, which is associated with the heat sink, and segment strength) equal to 20-22 mm, and located at an angle of 30 ° to the horizon the segment is selected depending on the thickness of the rib, provided that the rib enters the groove with a gap, the smallest segment thickness (in the lower part of the hinged segment) is also accepted as low as possible (according to the conditions of high-quality pressing of the refractory mass) and equal to 35-40 mm

For the proposed segment design, the radius of the outer cylindrical surface of the segment is determined from the expression

RH S4-RT + (5 + b, (1) where S is the distance between the axes of the outer and inner cylindrical surfaces of the segment (eccentricity), mm;

RY - radius (outer) of the bottom tube, mm; O - the gap between the pipe and the inner

segment surface, mm; 6 (35-40) segment thickness at the thinnest point (lower part), mm, and the inner cylindrical surface of the segment from the expression

 (2)

To ensure that the torque from the force of gravity pressed the segment to the bottom surface of the bottom tube, and the maximum thickness of the segment (in its upper part) was minimal (due to "shading the heated metal segment), the minimum possible eccentricity ratio between external and internal cylindrical surfaces of the S segment to the radius of the bottom tube R, equal to S / RT 0.5-0.6, where 0.5 corresponds to the largest and 0.6 to the smallest diameter of the bottom tube. The size of the gap between the segment and the bottom tube (5 is determined by the stability of the mounting ribs, which is caused by the heat sink of the rib. As the bench studies showed, under the conditions of the heat sink for the whole range of the bottom tubes, the optimum gap between the segment and the bottom tube is S 10-15 mm. For the entire diameter range of the bottom tube, the ratio of the radius of the inner cylindrical surface of the segment to the outer radius of the bottom tube RBH / RT varies from 1.0 for the largest diameter of the bottom tube when the segments are suspended a bottom tube without gap (b 0), to 1.37 for the smallest diameter of the bottom tube (RT 40 mm) and maximum gap value (6 15 mm). The ratio of the radius of the outer cylindrical surface of the segment to the outer radius of the bottom tube varies from 1, 82 for the largest diameter of the bottom tube (RT 110 mm) with the suspension of the segment to the bottom tube without a gap (() up to 2.85 for the smallest diameter of the bottom tube and the maximum gap value & Example. For the bottom tube, an outer diameter of 168 mm (R 84 mm) and a gap between the bottom tube and the inner cylindrical surface of the segment equal to b 10 mm, the segment dimensions are as follows: S 46 mm 0.55 Rg 84 + 10 94 mm - 1, formula 2); К „46 + 84 + 10 + mm 2,08 R, (according to formula I). Thus, thermal insulation, the refractory blocks of which are made in the form of segments with such an eccentric arrangement of the outer and inner cylindrical surfaces and hung on the ribs of the bottom pipe with a gap between the bottom pipe, its edge and the segment itself, has the following advantages over lime. Under the action of its own weight, the insulation blocks are pressed against the bottom surface of the bottom tube ("self-clamping insulation), which ensures a stable position of the block relative to the block attachment to the tube, thereby increasing the reliability of the block fixing to the tube, increasing the quality of the insulation, its durability. The refractory insulation blocks do not experience external mechanical impacts from the advancement of the workpieces, since they are covered with protective visors welded to the upper part of the bottom tube, which also increases the resistance of the insulation. The isolation blocks are suspended without mutual engagement, both between themselves and with adjacent links, there are gaps between the bottom tube, its edge and the block itself, which virtually eliminates additional loads on the refractory blocks not only in a static position, but also when the tube vibrates ( when moving metal on the feeder). The thickened upper part (strengthens the refractory block at the place of block attachment to the pipe), as well as the simplicity of the block forms (no small parts) make it possible to obtain blocks with high strength properties during pressing.

Claims (1)

THERMAL INSULATION OF UNDER PIPES, containing refractory cylindrical blocks, covering the pipe symmetrically, having grooves in the upper part and grooves for hanging them on the pipe ribs, characterized in that, in order to increase the insulation resistance, the outer surface of each block is made with a radius of 1.82—2 , 85 of the radius of the pipe, and the inner surface with a radius of 1.0-1.37 of the radius of the pipe, while the axes of the indicated surfaces of the blocks are eccentric at a distance of 0.5-0.6 of the radius of the pipe. SB SL CX>