RU2370717C1 - Vacuum oven - Google Patents

Abstract

FIELD: personal demand items.

SUBSTANCE: oven consists of a hollow housing with end covers, one of which is fixed on the housing, and the other one is provided with the possibility of being moved, as well as end, side, upper and lower heater units which are arranged in the housing; at that, lower heater unit is the bottom and has the possibility of being moved back-and-forth by means of feed-and-removal mechanism, and on the bottom there are mounting seats for the item to be installed. The oven is equipped with a flange with an annular protrusion fixed on the housing end on the side of the movable cover provided with an annular seal on its end contacting the flange end; on the movable cover generatrix there is an annular groove wherein a pneumatic seal is located, which has the possibility, when the cover is in the closed position, of interacting with the flange protrusion generatrix which forms together with the cover generatrix an annular chamber connected to the vacuum system.

EFFECT: increasing efficiency and obtaining high-quality products.

4 cl, 4 dwg

Description

The invention relates to thermal equipment and can be used in the design of furnaces for heat treatment and / or soldering of products, for example heat exchangers made of aluminum alloys.

Known high-temperature vacuum electric furnace containing a water-cooled housing with two end caps, which houses thermal screens and heating elements. End heat shields are made in the form of single or multi-auger screws attached to the covers by means of brackets. A table for mounting the workpiece is mounted on the hearth in the hearth furnace. Under can be made withdrawable. Loading and unloading of the product is carried out by rolling one of the end caps pivotally connected to the hearth. They are installed on the under the product, rolled under the furnace, close the end cover, seal its joint with the end of the case. Turn on the furnace system, for example, vacuum, heating the working space of the furnace, and hold the product in the furnace for a specified time, then turn off the system, if necessary, cool the processed product, open the lid and roll out under the table on which the product is located. Remove the product from the table.

(See A.S. USSR No. 1446434, class F27B / 04, 1988)

As a result of the analysis of the design of the known furnace, it should be noted that the heating elements installed in its body do not provide uniform heating of the working volume of the body, especially if it has an elongated shape. This leads to lower quality products. In addition, the design of this furnace does not guarantee the reliability of the joint “movable cover - end face of the joint” and, as a result, the quality of processing is reduced.

Known electric furnace containing a hollow body with end caps. One cover is permanently attached to the casing, and the second has the ability to move (rollback from the furnace casing). The retractable lid is mounted on a self-propelled trolley moving along rails (rails).

Consoles are mounted on the inner surface of the movable cover, on which thermal screens are installed. Under (the position is not indicated) is made roll-out. It has a table for installing the product. A heating element is installed on the inner surface of the movable cover, made in the form of a U-shaped plate through a current supply connected to a power source.

A second heating element is mounted in the housing, made in the form of a U-shaped plate, by means of a current supply connected to a power source.

Thermal screens are also mounted in the casing.

The heating elements have an identical shape, are installed horizontally, with end walls to the covers, respectively, on the cover and in the housing with a 90 ° turn relative to each other relative to the axis of the furnace body. Heating elements are made of heat-resistant sheet metal.

(See published application No. 2006144911, class F27B 5/04, published June 27, 2008 — the closest analogue.)

As a result of the analysis of the design of this furnace, it should be noted that the mechanism for fixing the front cover at the end of the body is complicated, fixing takes a long time, which does not guarantee reliable sealing of the working volume of the furnace at the junction with the front cover. In addition, the known design of the furnace does not allow for the adjustment of the position of the product in the processing zone. All this reduces the productivity of the furnace and the quality of processing products in it.

The objective of the present invention is to develop the design of a vacuum furnace with high performance in operation and allowing to obtain products of consistently high quality.

The task is ensured by the fact that in a vacuum furnace containing a hollow body with end caps, one of which is mounted on the body and the other has the ability to move, as well as end, side, upper and lower heater blocks placed in the housing, made in the form of panels with screen insulation, the last screen of the heater blocks is a supporting structure, and the lower heater block is mechanically connected to the sliding cover and has the ability to reciprocate, performing the function ode in which the product is installed. On the lower block of the heater (bottom) there are base surfaces for installing the product. In the sliding cover at the end of its flange in contact with the housing flange, a cord seal is installed, and an inflatable seal is installed along the forming flange in the groove. The front flange of the housing in the end part is equipped with an annular protrusion; in the closed position, the inflatable seal of the lid interacts with the inner surface of the protrusion, while the annular chamber formed by the seals and the protrusion is connected to the vacuum system.

The seats of the lower block of the heater (hearth) intended for installation of the product may have the ability to adjust movement vertically.

When conducting patent research from the prior art, no solutions are identified that are identical to the claimed, and therefore, the claimed invention meets the condition of patentability “novelty”. The essence of the claimed invention does not follow explicitly from solutions known from the prior art, and therefore, the claimed invention meets the condition of patentability "inventive step".

The information set forth in the application materials is sufficient for the practical implementation of the invention.

The invention is illustrated by drawings, in which:

figure 1, 2 - vacuum oven, General view;

figure 3 - remote element A in figure 1;

figure 4 - remote element B in figure 1.

The vacuum furnace contains a hollow body 1 of predominantly cylindrical shape with end caps 2 and 3. The cover 2 (rear) is fixed to the body 1, and the cover 3 (front) has the ability to move, that is, it is retracted from the end of the body into which loading and unloading is carried out products (products).

Case 1, covers 2 and 3 are water-cooled. Their cooling system is known and is not described in the materials of this application.

In the furnace body 1, heater blocks are placed: front front 4, front rear 5, side left 6, side right 7, upper 8 and lower 9.

The blocks of heaters form a closed space in which the product is processed (for example, soldering). Each block of heaters is made in the form of a layered package consisting of shields 10, electrical insulators 11 and resistive zig heaters 12. The end blocks of the heaters are mounted on the covers, and the rest are installed inside the furnace body. The outer screen of all heating blocks is a supporting structure.

On the outer screens of the heater blocks (side, top and bottom), rolling bearings 13 are installed, thanks to which the blocks move along the guides of the furnace body.

The lower block of the heater 9 is a roll-out hearth, the outer screen of which is pivotally coupled to the cover 3.

The cover 3 through a ball joint 14 is suspended on a support mounted on a loading-unloading device.

The draw-out under has two positions:

1) front (working) - when the product is inside the furnace body;

2) back (loading-unloading of the product) - when under is located outside the furnace.

On the hearth provided seats "B" (figure 4), allowing vertical movement of the pallet 15, for example, by installing sleeves 16, providing a given position of the product along the height of the furnace, which allows heating of the product in optimal conditions.

At the end of the lid 3 (Fig.3), facing the flange 17 of the housing 1, there is a seal 18, for example, in the form of a cord. On the generatrix of the cover 3 there is an annular groove in which the end-face inflatable seal 19 is located. The inner diameter of the protrusion of the flange of the housing 17 is slightly larger than the outer diameter of the flange of the cap 3, which enters the cavity of the protrusion of the flange, that is, between the outer surface of the flange of the cover and the inner surface of the protrusion of the flange of the housing annular clearance (annular cavity) 20.

The furnace is equipped with a vacuum system for evacuating the cavity of the housing 1 and the cavity 20. The implementation of the vacuum system is known.

Naturally, to ensure the functioning of the furnace, it is equipped with all necessary means: a heating system for the working space of the furnace, a cooling system for the furnace, a vacuum system for the furnace cavity, a system for measuring the temperature of the furnace, etc. All these tools are known to specialists, they do not constitute a patent subject and therefore no need for a detailed description of them.

A vacuum oven operates as follows. We will consider the operation of the furnace using the example of soldering an aluminum alloy heat exchanger.

The furnace must be connected to all its systems. Under 9 roll out to the rear position. On the pallet 15 install the item to be soldered, for example a radiator. The sleeves 16 adjust the position of the product in height, ensuring that when soldering in the furnace it occupies a position that ensures its uniform heating from all sides. Depending on the size of the product and the working volume of the furnace, one or more radiators can be loaded into the furnace. Therefore, the term "product" in this application should be understood as one product, or several, simultaneously undergoing processing in an oven. The use of spacer sleeves 16 provides the necessary position of the product in height. To obtain high-quality products, it is necessary that the product is located at approximately equal distances from the heating elements of the heater blocks, therefore, when changing the dimensions of the products, it is necessary to adjust their position in the furnace by means of elements 16. It can also be washers, gaskets, etc. Such adjustment ensures the same temperature processing mode of the entire product, which improves the quality of processing.

After installing the product on the pallet from the control panel, they give a command to move the hearth 9 to the front position, as a result of which the product moves into the furnace cavity and is located in the processing zone (inside the cavity formed by the heater blocks 4-9). The working surface of the cover 3 is located inside the protrusion of the flange 17 of the cavity 20. The seal 18 is pressed against the end surface of the flange 17.

Turn on the vacuum system to pump out the atmosphere of the housing. Upon reaching a residual pressure of not more than 100 mm Hg open the valve, through which the atmosphere is supplied under pressure to the inflatable seal 19. The seal is inflated, pressed to the inner surface of the protrusion of the flange 17 and seals the cavity 20. After sealing the cavity 20, the valve opens and the vacuum system is connected. This eliminates the ingress of the atmosphere into the cavity of the furnace seal 19.

The advantages of this cover-flange connection are: complete absence of fasteners; fixing the cover in the closed position is very fast; the cavity of the furnace is securely sealed from the front cover side; the manufacturing technology of the flange and the cover is simplified, since their surfaces are installed relative to each other with a gap; the cover cannot be retracted from the flange until the cavity 20 is depressurized.

Due to the fact that the product is in a closed volume at an equal distance from the heating elements, the product is heated simultaneously from all sides, inside this volume, the set temperature is maintained throughout the entire technological cycle, which allows soldering with high quality.

The temperature and pressure in the furnace during the processing of the product are controlled by sensors.

At the end of the soldering process, the furnace systems are turned off, the working volume is filled with atmosphere, the pressure is removed from the inflatable seal 19 and the cover 3 is unlocked with the housing 1. By moving the loading-unloading mechanism, the cover 3 is removed from the end of the housing 1 and the finished product is rolled out of the furnace cavity. Remove the product from the pallet, install a new product to be processed on it, and then the cycle repeats.

This furnace can be used not only for soldering, but also for heating and heat treatment of products.

Claims (4)

1. A vacuum furnace containing a hollow body with end caps, one of which is mounted on the body, and the other is movable, end, side, upper and lower heater blocks and a vacuum system are placed in the housing, the lower heater block being a hearth and has the possibility of reciprocating movement through the mechanism of loading and unloading, and on the hearth made seats for installation of the product, characterized in that it is equipped with a flange with an annular protrusion mounted on the end of the housing with on the side of the movable cover having, at its end contacting the end of the flange, an annular seal, the movable cover being made with an annular groove along its generatrix, in which an inflatable seal is placed having in the closed position of the lid the interaction of the protrusion of the flange along its generatrix to form an annular chamber connected to a vacuum system. 2. The vacuum furnace according to claim 1, characterized in that the inflatable seal is made with the function of a locking device. 3. The vacuum oven according to claim 1, characterized in that the heating blocks are made in the form of panels in which the external cold screen is a supporting structure, while the rolling bearings are installed on the side, upper and lower outer screens of the blocks. 4. The vacuum oven according to claim 1, characterized in that the seats of the lower block of heaters are designed to install the product and have the ability to adjust movement vertically.

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