RU2544724C2 - Shaft furnace - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: invention relates to a shaft furnace for heat treatment of parts. A furnace includes an external frame, a muffle, which are isolated from each other with fibrous heat insulation, a cover plate, a lifting mechanism, a vessel and electrical equipment. The cover plate is lined with fibrous heat insulation by means of pins and brackets located inside the heat insulation and attached to the upper cover. Fibrous heat insulation of the cover plate is covered with insulation fabric.

EFFECT: providing safe operation of a furnace, uniform heating of a working space of a furnace and improving heat treatment quality of parts.

6 cl, 2 dwg

Description

The invention relates to the field of engineering, and in particular to devices for heat treatment of parts.

Known electric furnace (mine high-temperature electric furnace ПШЗ 10.20 / 9, INSTRUCTIONS FOR USE, firm "Nakal", Equipment for heat treatment), made in a welded frame made of profile and sheet metal, lined with fireclay bricks. The furnace is equipped with a hydraulic lifting mechanism, the lid is lifted up by a hydraulic pump and pulled to the side.

The disadvantages of the prototype are:

- uneven heating;

- long heating and cooling times (high inertia);

- the complexity of manufacturing chamotte masonry;

- quick wear of the masonry;

- lack of control of the wear of the hydraulic cylinder seal;

- the inability to enter the control thermal converter and pipelines for the supply of inert gases.

The proposed invention solves the problem:

- improving the quality of heat treatment of parts;

- reducing the complexity of manufacturing a shaft furnace;

- ensuring safety when working with the furnace;

- increase the life of the furnace.

The technical result of the invention is:

- uniform heating of the working space of the furnace;

- short time of heating the furnace and its cooling;

- reducing the complexity of manufacturing due to the less costly design of the furnace;

- reduction of power consumption;

- control of the wear of the hydraulic cylinder seal;

- free entry of a control thermocouple and pipelines for the supply of inert gases;

- safe operation of the shaft furnace;

- weight reduction.

The specified technical result is achieved in that in the shaft furnace, consisting of an external frame, a muffle isolated from each other by fiber insulation, a cover, a lifting mechanism, a retort, electrical equipment, it is new that there is an air gap between the muffle and the external frame with fiber insulation .

In the shaft furnace on the frame, a limit stop may be located.

In the furnace, the shaft lifting mechanism may be provided with a locking stop.

A hole for diagnostics may be provided in the shaft furnace in the hydraulic cylinder of the lifting mechanism.

In the furnace, the shaft cover can be lined with fibrous thermal insulation in a certain way using pins and brackets located inside the insulation and fixed to the upper closure, and the fibrous thermal insulation is covered with a heat-insulating fabric.

In the furnace, the mine lining of the working area can be made with fireclay plates, which are attached to the outer frame with studs.

In the shaft furnace, a chute can be located in the chamotte plate connecting the outer frame and the muffle.

The muffle is lined in the working area with chamotte plates. The external frame is insulated with fiber insulation. An air gap is provided between the muffle and the frame. The fibrous insulation of the outer frame is separated from the outer closure by an air gap. A double air gap reduces heat transfer to the outer surface of the furnace, which ensures safe operation near the shaft furnace and reduces power consumption.

A limit stop is provided on the frame, which, when the lid is closed, guarantees its correct position in the horizontal plane.

The shaft furnace is equipped with a locking stop, which, when the lid is open, fixes its position, which allows safe loading and unloading of parts.

The hydraulic cylinder of the lifting mechanism contains a hole for diagnosing the integrity of the seal, which allows you to change the seal in time.

The cover is a welded structure, lined in a certain way with fibrous thermal insulation. The thermal insulation is attached to the upper closure with pins and brackets that are located inside the thermal insulation, that is, there are no metal structures in the heating zone, which reduces power consumption.

The thermal insulation is covered with an insulating cloth to prevent premature wear of the fiber and getting it into the working space of the furnace, which improves the quality of heat treatment of parts, as well as on the outer surface of the furnace when opening and closing, making the work on the furnace safe. The fibrous insulation of the lid allows you to align the muffle masonry, thereby improving the sealing of the furnace working area.

The lining of the muffle is made of fireclay plates, which are fixed with studs to the frame of the muffle. Studs can reduce the pressure on the bottom of the shaft furnace, which prevents premature destruction of thermal insulation and loss of fireclay plates, and also reduces the complexity in the manufacture of shaft furnace. Fireclay plates have a short cooling time, which reduces the inertia of the furnace.

The external frame and the muffle are interconnected by a fireclay plate in the upper part of the furnace to improve sealing of the working area. A gutter is located in the plate for introducing a control thermal converter and for supplying an inert gas in the case of heat treatment of parts in a protective atmosphere. The gutter is blocked by fibrous insulation of the lid.

All of the above distinguishing features allow you to get parts of very high quality after heat treatment.

Technical solutions with features distinguishing the claimed solution from the prototype are not known and do not follow explicitly from the prior art. This allows us to consider that the claimed solution is new and has an inventive step.

The invention is illustrated by drawings, where figure 1 shows a structural diagram of a shaft furnace; figure 2 - view A; figure 3 is a view of B; figure 4 is a diagram of the laying of the thermal insulation of the cover, figure 5 is a trough for the input control thermocouple and the pipeline for inert gas.

The shaft furnace consists of an external frame 1 and a muffle 2, which are closed by a cover 3 by means of a lifting mechanism 4. A muffle 2 is placed inside the external frame 1. The external frame 1 and the muffle 2 are connected by fireclay plates 5 in the upper part of the furnace. In the plate 5 there is a groove 6 for introducing a control thermal converter or supplying an inert gas. The groove 6 is blocked by the fibrous insulation of the lid. The muffle 2 is lined with fireclay plates 7 in the working area, which are fastened with pins 8 to the frame of the muffle 9. The muffle 2 is isolated from the outer frame 1, equipped with fiber insulation 10, with an air gap 11 to prevent heat transfer to the outer surface of the furnace. In the working space along the walls of the muffle 2 on the ceramic screws 12 are spiral heaters 13, wound on ceramic tubes 14. Inside the muffle 2 a retort 15 is installed, which is a welded construction of sheet metal and a bar. Retort 15 allows you to equalize the temperature inside the furnace. The lid 3 is lined in a certain way with the help of pins 16 and brackets 17 located in the heat insulation 18. The fiber insulation 18 of the lid 3 is closed with an insulating cloth 19. The brackets 17 are attached to the upper closure 20 and do not have contact with the shaft of the shaft furnace, which reduces heat transfer the outer surface of the furnace, thereby ensuring safe operation near the furnace and reducing power consumption. The closed cover 3 is limited in movement by a stop 21, which is located on the outer frame 1. The cover 3 can be opened using a lifting mechanism 4. The lifting mechanism 4 is a prefabricated structure consisting of a hydraulic cylinder 22, a stop 23, brackets 24 and 25, a hydraulic pump 26 The hydraulic cylinder 22 is a prefabricated structure with which the cover 3 rises and lowers. The hydraulic cylinder 22 has a diagnostic hole 27 that allows you to control the wear of the seal 28. The movement of the cylinder piston is carried out with with the help of a hydraulic pump 26. The stop 23 serves as a rotary mechanism of the hydraulic cylinder 22 and the cover 3. The brackets 24 and 25 connect the hydraulic cylinder 22 and the cover 3. A locking stop 29 is located on the lifting mechanism 4, which secures the cover 3 in the open state.

A proximity switch 30 is installed on the frame, which serves to turn off the heaters 13 when opening the cover 3. Inside the retort 15, temperature sensors 31 are installed to monitor the temperature regime in the working area. The sensors are connected to an automated control system, which includes "Multichannel temperature controllers" Thermodat 16E5 "(see Instructions for use by the manufacturer Instrument-making enterprise" Control Systems ", Perm, Kostycheva St., 42 A). The devices allow temperature control according to the proportional-integral-differential (PID) law, minimizing the inertia of the system for maintaining the set temperature in each zone, as well as allowing remote control of the shaft furnace using a computer. Temperature control devices and controls for the shaft furnace are included in electrical equipment 32. To prevent the destruction of plates 5 and regulate the closure density of the lid 3 there are adjustable stops 33.

The shaft furnace works as follows.

The shaft furnace is set to a predetermined mode by the value set on the adjustable channels of Thermodat 16E5 and by selecting the PID coefficients of the control law that ensure the minimum inertia of the system for maintaining the set temperature. Details are loaded into the shaft furnace, for which they open the lid 3 using a lifting mechanism 4 and fix it with an emphasis 29, then close it, press the lid 3 tightly against the muffle 2 masonry due to its weight, the correct closure provides the limit stop 21. Turn on the heating. There is a heat treatment process. The exposure time of parts in a shaft furnace is determined by the technological process. After the heat treatment process, the heating is turned off. To quickly lower the temperature, it is necessary to open the lid 3 by adjusting the stops 33 or turn it by a small angle. After cooling the shaft furnace, which is controlled by Thermodat 16E5 devices, open the lid and unload the parts.

Claims (6)

1. A shaft furnace containing an external frame, a muffle insulated from the frame by fibrous insulation, a cover, a lifting mechanism and a retort, characterized in that the cover is lined with fiber insulation, fixed to the upper closure by means of pins and brackets located inside the insulation without contact with the working area shaft furnace, while the fibrous insulation is closed with a heat-insulating fabric. 2. The furnace according to claim 1, characterized in that a hole for diagnosis is provided in the hydraulic cylinder of the lifting mechanism. 3. The furnace according to claim 1, characterized in that the lining of the working area is made of fireclay plates, which are attached to the outer frame with studs. 4. The furnace according to claim 3, characterized in that in the chamotte plate connecting the outer frame and the muffle, a gutter is located. 5. The furnace according to claim 1, characterized in that there is an air gap between the outer frame with fibrous insulation and the muffle. 6. The furnace according to claim 1, characterized in that the limit stop is located on the frame.

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