阅读说明：本技术 一种真空烤箱 (Vacuum oven ) 是由 刘亿锋 何世检 李辉进 刘淼城 谢志清 于 2020-07-30 设计创作，主要内容包括：本发明公开了一种真空烤箱,通过循环风道及发热包的设置,发热管群产生热量后,经过风扇向左侧板及右侧板吹出,热量不断从左斜板、左直板、右斜板及右直板达到内腔室的各个位置,并从背板再次进入风扇,形成热量循环,可以快速均衡内腔室各位置的热量,还可以解决门板处较难加热的问题。本发明真空烤箱,包括烤箱主体及至少一个内腔室,所述内腔室内设置有循环风道及发热包；所述循环风道包括左侧板、背板及右侧板,所述左侧板包括左斜板及左直板,所述右侧板包括右斜板及右直板；所述发热包设置于真空烤箱的内腔室与循环风道之间,包括中部分隔板及在所述中部分隔板两侧对称设置的发热包模块。(The invention discloses a vacuum oven, wherein through the arrangement of a circulating air channel and a heating bag, after a heating tube group generates heat, the heat is blown out from a left side plate and a right side plate through a fan, the heat continuously reaches each position of an inner chamber from a left inclined plate, a left straight plate, a right inclined plate and a right straight plate, and enters the fan again from a back plate to form heat circulation, so that the heat at each position of the inner chamber can be quickly balanced, and the problem that a door plate is difficult to heat can be solved. The invention discloses a vacuum oven, which comprises an oven main body and at least one inner chamber, wherein a circulating air duct and a heating bag are arranged in the inner chamber; the circulating air duct comprises a left side plate, a back plate and a right side plate, the left side plate comprises a left inclined plate and a left straight plate, and the right side plate comprises a right inclined plate and a right straight plate; the heating bag is arranged between the inner chamber of the vacuum oven and the circulating air duct and comprises a middle partition plate and heating bag modules symmetrically arranged on two sides of the middle partition plate.)

1. A vacuum oven comprises an oven main body and at least one inner chamber, and is characterized in that a circulating air duct and a heating bag are arranged in the inner chamber;

the circulating air duct comprises a left side plate, a back plate and a right side plate, the left side plate comprises a left inclined plate and a left straight plate, and the right side plate comprises a right inclined plate and a right straight plate;

the left side plate, the back plate and the right side plate form a flat-bottom U-shaped structure, the left inclined plate and the right inclined plate are arranged at the top of the flat-bottom U-shaped structure, and the left inclined plate and the right inclined plate form an inverted V-shaped structure; one side of the left inclined plate is abutted against the opening of the inner chamber, and the other side of the left inclined plate is connected with the left straight plate; one side of the right inclined plate is abutted to the opening of the inner chamber, and the other side of the right inclined plate is connected with the right straight plate; the left side plate and the right side plate are both provided with vent holes;

the heating bag is arranged between the inner chamber of the vacuum oven and the circulating air duct and comprises a middle partition plate and heating bag modules symmetrically arranged on two sides of the middle partition plate;

the middle part of the back plate is provided with a vent hole, and the middle part of the partition plate is arranged in the middle of the back plate and connects the back plate with the back surface of the inner side of the inner cavity; the heating bag module comprises a heating bag shell, a heating pipe group and a fan, wherein an air inlet and an air outlet are formed in two ends of the heating bag shell respectively, the air inlet faces the middle partition plate, the fan is installed on the air inlet, and the air outlet faces the left side plate or the right side plate and a side wall air channel formed by the inner side of the inner chamber; the heating pipe group is arranged in the heating bag shell and between the air inlet and the air outlet.

2. The vacuum oven of claim 1, wherein the left inclined plate, the left straight plate, the right inclined plate and the right straight plate are uniformly provided with vent holes;

the middle part of the back plate is uniformly provided with vent holes.

3. The vacuum oven of claim 2, wherein the area of the back plate aperture is one-fourth to one-half of the area of the back plate.

4. The vacuum oven of any one of claims 1 to 3 wherein the circulating air duct further comprises a ceiling;

the top plate comprises a top inclined plate and a top straight plate, one side of the top inclined plate is abutted against the opening of the inner chamber, and the other side of the top inclined plate is connected with the top straight plate;

one side of the top straight plate is connected with the top inclined plate, and the other side of the top straight plate is connected with the back plate;

the top sloping plate and the top straight plate are evenly provided with vent holes.

5. The vacuum oven of claim 1, wherein the heat-generating pack housing is a cuboid-like structure comprising a left end face, a right end face, and four side faces;

the right end face is an inclined face, and an included angle formed by the right end face and the back plate is an acute angle;

a groove position for mounting the fan is formed in the right end face;

the cuboid-like structure is in the one end at left end face place is close to the end angle of the inner chamber indoor side is the cambered surface design, is close to the end angle department of backplate has seted up the cross-section and has been L type trench, L type trench is the air outlet.

6. The vacuum oven of claim 5, wherein said fans are two;

the right end face is provided with two slot positions.

7. The vacuum oven of claim 5 or 6, wherein the heat generating tube group is a combination of a plurality of heat generating tubes;

the heating tubes are arranged in the heating bag shell in a honeycomb manner.

8. The vacuum oven of claim 7, wherein the heat-generating tube is a hollow copper tube;

and a heating wire is arranged in the hollow copper pipe.

9. The vacuum oven of claim 1, further comprising a cooling device disposed between the vacuum oven's oven body and the interior chamber;

the cooling device comprises a fan, a back air duct and a bent duckbill air duct which are sequentially connected;

the fan, the back air duct and the bent duckbill air duct are arranged on the back of the outer side of the inner chamber;

connectors are arranged at two ends of the back air duct, one connector is connected with an air outlet of the fan, and the other connector is connected with an air inlet of the bent duckbill air duct;

the air outlet in bent type duckbilled wind channel extends to the first side of interior chamber, the air intake of fan is close to the second side of interior chamber, first side reaches the second side sets up relatively and with horizontal plane mutually perpendicular.

10. The vacuum oven of claim 9, wherein a cooling air conditioner is further provided on the oven body;

and an air outlet of the cooling air conditioner is arranged between the box body and the inner chamber.

Technical Field

The invention relates to the field of drying equipment, in particular to a vacuum oven.

Background

A vacuum oven is a box type drying device for drying a drying material under a negative pressure condition. The principle is as follows: the vacuum pump is used for pumping air and dehumidifying, so that a vacuum state is formed in the working chamber, the boiling point of water is reduced, and the drying speed is accelerated.

Traditional vacuum oven locates the heating tube in the oven, utilizes the heating tube to dry article after the heated air, can lead to the local high temperature of the position of heating tube place usually. Because the space of the industrial oven is large, the air heat is heated unevenly, so that the drying efficiency is not high, and excellent products cannot be produced. In addition, the heat is generally difficult to be transmitted to the door plate of the vacuum oven, so that the material close to the door plate is difficult to be heated well.

Disclosure of Invention

The invention discloses a vacuum oven, wherein through the arrangement of a circulating air channel and a heating bag, after a heating tube group generates heat, the heat is blown out from a left side plate and a right side plate through a fan, the heat continuously reaches each position of an inner chamber from a left inclined plate, a left straight plate, a right inclined plate and a right straight plate, and enters the fan again from a back plate to form heat circulation, so that the heat at each position of the inner chamber can be quickly balanced, and the problem that a door plate is difficult to heat can be solved.

The vacuum oven comprises an oven main body and at least one inner chamber, wherein a circulating air duct and a heating bag are arranged in the inner chamber;

the circulating air duct comprises a left side plate, a back plate and a right side plate, the left side plate comprises a left inclined plate and a left straight plate, and the right side plate comprises a right inclined plate and a right straight plate;

the left side plate, the back plate and the right side plate form a flat-bottom U-shaped structure, the left inclined plate and the right inclined plate are arranged at the top of the flat-bottom U-shaped structure, and the left inclined plate and the right inclined plate form an inverted V-shaped structure; one side of the left inclined plate is abutted against the opening of the inner chamber, and the other side of the left inclined plate is connected with the left straight plate; one side of the right inclined plate is abutted to the opening of the inner chamber, and the other side of the right inclined plate is connected with the right straight plate; the left side plate and the right side plate are both provided with vent holes;

the heating bag is arranged between the inner chamber of the vacuum oven and the circulating air duct and comprises a middle partition plate and heating bag modules symmetrically arranged on two sides of the middle partition plate;

the middle part of the back plate is provided with a vent hole, and the middle part of the partition plate is arranged in the middle of the back plate and connects the back plate with the back surface of the inner side of the inner cavity; the heating bag module comprises a heating bag shell, a heating pipe group and a fan, wherein an air inlet and an air outlet are formed in two ends of the heating bag shell respectively, the air inlet faces the middle partition plate, the fan is installed on the air inlet, and the air outlet faces the left side plate or the right side plate and a side wall air channel formed by the inner side of the inner chamber; the heating pipe group is arranged in the heating bag shell and between the air inlet and the air outlet.

Preferably, the first and second liquid crystal materials are,

the left inclined plate, the left straight plate, the right inclined plate and the right straight plate are uniformly provided with vent holes;

the middle part of the back plate is uniformly provided with vent holes.

Preferably, the first and second liquid crystal materials are,

the area of the back plate opening is one fourth to one half of the area of the back plate.

Preferably, the first and second liquid crystal materials are,

the circulating air duct also comprises a top plate;

the top plate comprises a top inclined plate and a top straight plate, one side of the top inclined plate is abutted against the opening of the inner chamber, and the other side of the top inclined plate is connected with the top straight plate;

one side of the top straight plate is connected with the top inclined plate, and the other side of the top straight plate is connected with the back plate;

the top sloping plate and the top straight plate are evenly provided with vent holes.

Preferably, the first and second liquid crystal materials are,

the heating bag shell is of an approximately cuboid structure, and the approximately cuboid structure comprises a left end face, a right end face and four side faces;

the right end face is an inclined face, and an included angle formed by the right end face and the back plate is an acute angle;

a groove position for mounting the fan is formed in the right end face;

the cuboid-like structure is in the one end at left end face place is close to the end angle of the inner chamber indoor side is the cambered surface design, is close to the end angle department of backplate has seted up the cross-section and has been L type trench, L type trench is the air outlet.

Preferably, the first and second liquid crystal materials are,

the number of the fans is two;

the right end face is provided with two slot positions.

Preferably, the first and second liquid crystal materials are,

the heating tube group is a combination of a plurality of heating tubes;

the heating tubes are arranged in the heating bag shell in a honeycomb manner.

Preferably, the first and second liquid crystal materials are,

the heating tube is a hollow copper tube;

and a heating wire is arranged in the hollow copper pipe.

Preferably, the first and second liquid crystal materials are,

the cooling device is arranged between the box body and the inner cavity of the vacuum oven;

the cooling device comprises a fan, a back air duct and a bent duckbill air duct which are sequentially connected;

the fan, the back air duct and the bent duckbill air duct are arranged on the back of the outer side of the inner chamber;

connectors are arranged at two ends of the back air duct, one connector is connected with an air outlet of the fan, and the other connector is connected with an air inlet of the bent duckbill air duct;

the air outlet in bent type duckbilled wind channel extends to the first side of interior chamber, the air intake of fan is close to the second side of interior chamber, first side reaches the second side sets up relatively and with horizontal plane mutually perpendicular.

Preferably, the first and second liquid crystal materials are,

the box body is also provided with a cooling air conditioner;

and an air outlet of the cooling air conditioner is arranged between the box body and the inner chamber.

The vacuum oven comprises an oven main body and at least one inner chamber, wherein a circulating air duct and a heating bag are arranged in the inner chamber; the circulating air duct comprises a left side plate, a back plate and a right side plate, the left side plate comprises a left inclined plate and a left straight plate, and the right side plate comprises a right inclined plate and a right straight plate;

the left side plate, the back plate and the right side plate form a flat-bottom U-shaped structure, the left inclined plate and the right inclined plate are arranged at the top of the flat-bottom U-shaped structure, and the left inclined plate and the right inclined plate form an inverted V-shaped structure; one side of the left inclined plate is abutted against the opening of the inner chamber, and the other side of the left inclined plate is connected with the left straight plate; one side of the right inclined plate is abutted to the opening of the inner chamber, and the other side of the right inclined plate is connected with the right straight plate; the left side plate and the right side plate are both provided with vent holes; the heating bag is arranged between the inner chamber of the vacuum oven and the circulating air duct and comprises a middle partition plate and heating bag modules symmetrically arranged on two sides of the middle partition plate; the middle part of the back plate is provided with a vent hole, and the middle part of the partition plate is arranged in the middle of the back plate and connects the back plate with the back surface of the inner side of the inner cavity; the heating bag module comprises a heating bag shell, a heating pipe group and a fan, wherein an air inlet and an air outlet are formed in two ends of the heating bag shell respectively, the air inlet faces the middle partition plate, the fan is installed on the air inlet, and the air outlet faces the left side plate or the right side plate and a side wall air channel formed by the inner side of the inner chamber; the heating pipe group is arranged in the heating bag shell and between the air inlet and the air outlet. Through the arrangement of the circulating air duct and the heating bag, after the heating tube group generates heat, the heat is blown out from the left side plate and the right side plate through the fan, the heat continuously reaches all positions of the inner chamber from the left inclined plate, the left straight plate, the right inclined plate and the right straight plate, and enters the fan again from the back plate to form heat circulation.

Drawings

FIG. 1 is a schematic diagram of a vacuum oven according to an embodiment of the present invention;

fig. 2 is a schematic diagram of an inner chamber 001 of a vacuum oven according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a circulating air duct in a vacuum oven according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a circulating air duct in a vacuum oven including a top plate 6 according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a heat-generating pack in a vacuum oven according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a vacuum oven including a cooling device according to an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a cooling device in a vacuum oven according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a cooling device in a vacuum oven including a cooling air conditioner 10 according to an embodiment of the present invention.

Detailed Description

The invention discloses a vacuum oven, wherein through the arrangement of a circulating air channel and a heating bag, after a heating tube group generates heat, the heat is blown out from a left side plate and a right side plate through a fan, the heat continuously reaches each position of an inner chamber from a left inclined plate, a left straight plate, a right inclined plate and a right straight plate, and enters the fan again from a back plate to form heat circulation, so that the heat at each position of the inner chamber can be quickly balanced, and the problem that a door plate is difficult to heat can be solved.

The technical solutions in the embodiments of the present invention are described in detail and clearly with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Referring to fig. 1 to 8, the vacuum oven of the present invention includes an oven main body 111 and at least one inner chamber 001, wherein a circulation air duct and a heat generating pack are disposed in the inner chamber 001;

the circulating air duct comprises a left side plate 1, a back plate 2 and a right side plate 3, the left side plate 1 comprises a left inclined plate 11 and a left straight plate 12, and the right side plate 3 comprises a right inclined plate 31 and a right straight plate 32;

the left side plate 1, the back plate 2 and the right side plate 3 form a flat-bottom U-shaped structure, the top of the flat-bottom U-shaped structure is provided with the left inclined plate 11 and the right inclined plate 31, and the left inclined plate 11 and the right inclined plate 31 form an inverted V-shaped structure; one side of the left inclined plate 11 is abutted against the opening of the inner chamber 001, and the other side of the left inclined plate is connected with the left straight plate 12; one side of the right inclined plate 31 is abutted to the opening of the inner chamber 001, and the other side of the right inclined plate 31 is connected with the right straight plate 32; the left side plate 1, the back plate 2 and the right side plate 3 are all provided with vent holes;

the heating bag is arranged between the inner chamber 001 of the vacuum oven and the circulating air duct and comprises a middle partition plate 4 and heating bag modules 5 symmetrically arranged on two sides of the middle partition plate 4;

a vent hole is formed in the middle of the back plate 2, and the middle partition plate 4 is arranged in the middle of the back plate 2 and connects the back surface of the back plate 2 with the back surface of the inner side of the inner chamber 001; the heating bag module 5 comprises a heating bag shell 51, a heating tube group 52 and a fan 53, wherein an air inlet 511 and an air outlet 512 are respectively formed at two ends of the heating bag shell 51, the air inlet 511 faces the middle partition plate 4, the fan 53 is installed on the air inlet 511, and the air outlet 512 faces a side wall air duct formed by the left side plate 1 or the right side plate 3 and the inner side of the inner chamber 001; the heat generation pipe group 52 is installed inside the heat generation pack case 51 between the air inlet 511 and the air outlet 512.

In the embodiment of the invention, during operation, the heat-generating tube group 52 generates heat, the fan 53 blows air to the heat-generating tube group 52, the heat is guided to the two side wall air channels of the circulating air channel, then the heat flows out through the vent holes on the left inclined plate 11, the left straight plate 12, the right inclined plate 31 and the right straight plate 32, finally enters the opening 42 from the vent hole of the back plate 2 again, and the heat circulation is realized through the fan 53. Through the design of the circulating air duct and the heating bag, after heat is generated, the heat quickly reaches each position of the inner chamber 001 through the circulating loop, particularly the door of the inner chamber 001, and the materials can be heated more uniformly. It should be noted that, the manner of the heat generating pack modules 5 symmetrically disposed on both sides of the middle partition plate 4 is mainly to form a double-loop circulation in the two side-wall air ducts, so as to more uniformly and rapidly disperse heat.

Preferably, the first and second liquid crystal materials are,

the left inclined plate 11, the left straight plate 12, the right inclined plate 31 and the right straight plate 32 are uniformly provided with vent holes;

the middle part of the back plate 2 is evenly provided with vent holes.

It should be noted that the design of the vent shape mainly takes into account the following two points: 1. whether heat circulation is facilitated; 2. whether the method is convenient for industrial production. In the embodiment of the invention, the selection of the combination of the round hole or the square hole and the round hole is considered to be convenient for processing, and the rigidity of the processed straight plate is improved.

Preferably, the first and second liquid crystal materials are,

the area of the opening of the back plate 2 is one fourth to one half of the area of the back plate.

Preferably, the first and second liquid crystal materials are,

the circulating air duct also comprises a top plate 6;

the top plate comprises a top inclined plate 61 and a top straight plate 62, one side of the top inclined plate 61 is abutted to the opening of the inner chamber 001, and the other side of the top inclined plate is connected with the top straight plate 62;

one side of the top straight plate 62 is connected with the top inclined plate 61, and the other side extends towards the direction of the back plate 2;

vent holes are uniformly formed in the top inclined plate 61 and the top straight plate 62.

It should be noted that the vacuum oven with the circulation air duct of the present invention may further include a top plate at the top of the inner side of the inner cavity 001, and the arrangement of the top plate may further enhance the heat circulation effect. However, it should be noted that one of the left side plate 1, the right side plate 3 or the top plate 6 may not be provided according to design requirements, especially considering the volume of the material placed inside the inner chamber 001, and is not limited herein.

Preferably, the first and second liquid crystal materials are,

the heating bag shell 51 is of an approximately cuboid structure, and the approximately cuboid structure comprises a left end face 513, a right end face 514 and four side faces 515;

the right end surface 514 is an inclined surface, and an included angle formed between the right end surface 514 and the backboard 2 is an acute angle;

a slot for mounting the fan 53 is formed in the right end surface 514;

the cuboid structure is in the one end at left end face 513 place, is close to the inboard end angle of interior chamber 001 designs for the cambered surface, is close to backplate 2's end angle department has seted up the cross-section and has been L type trench, L type trench is the air outlet.

Preferably, the first and second liquid crystal materials are,

the number of the fans 53 is two;

two slots are formed in the right end surface 514.

Preferably, the first and second liquid crystal materials are,

the heat generation tube group 52 is a combination of a plurality of heat generation tubes;

the plurality of heating tubes are arranged in the heating pack case 51 in a honeycomb shape.

Preferably, the first and second liquid crystal materials are,

the heating tube is a hollow copper tube;

and a heating wire is arranged in the hollow copper pipe.

Preferably, the first and second liquid crystal materials are,

the cooling device is arranged between the box body 002 and the inner cavity 001 of the vacuum oven;

the cooling device comprises a fan 7, a back air duct 8 and a bent duckbill air duct 9 which are connected in sequence;

the fan 7, the back air duct 8 and the bent duckbill air duct 9 are arranged at the back 0011 of the outer side of the inner chamber 001;

connectors are arranged at two ends of the back air duct 8, one connector is connected with the air outlet 71 of the fan 7, and the other connector is connected with the air inlet 91 of the bent duckbill air duct 9;

air outlet 92 of bent duckbilled wind channel 9 extends to the first side 0012 of interior chamber 001, air intake 71 of fan 7 is close to the second side 0013 of interior chamber 002, first side 0012 reaches second side 0013 sets up relatively and with horizontal plane mutually perpendicular.

Referring to fig. 6 and 7, in the embodiment of the present invention, the temperature of the inner chamber 001 after the heating process is relatively high, heat is dissipated to the outer peripheral surface of the inner chamber 001 in a heat exchange manner, when the fan 7 works, the heat is sucked from one side of the inner chamber 001 through the air inlet 91 and then is conveyed to the back air duct 8 from the air outlet 92, the back air duct 8 conveys the heat to the bent duckbill air duct 9 while dissipating the heat, the bent duckbill air duct 9 conveys the heat to the other side of the inner chamber 001, and the heat continuously circulates under the action of the fan 7 without being concentrated at a certain position, so that heat exchange can be performed rapidly, and the temperature of the inner chamber 001 can be reduced rapidly.

Preferably, the first and second liquid crystal materials are,

the box body 002 is also provided with a cooling air conditioner 10;

the air outlet of the cooling air conditioner 10 is arranged between the box body 002 and the inner chamber 001.

It should be noted that the cooling speed of the inner chamber 001 can be increased to a certain extent through the fan 7, the back air duct 8 and the bent duckbill air duct 9, but when the user needs to take out the heated material quickly, the speed of the cooling mode cannot meet the requirement of the user. Referring to fig. 8, a cooling air conditioner 10 may be additionally provided, and the cooling air conditioner 10 may rapidly reduce the temperature of the inner chamber 001 by delivering cold air to the outer circumferential surface of the inner chamber 001 and further circulating the cold air through the fan 7.

The vacuum oven comprises an oven main body 111 and at least one inner chamber 001, wherein a circulating air duct is arranged in the inner chamber 001; the circulating air duct comprises a left side plate 1, a back plate 2 and a right side plate 3, the left side plate 1 comprises a left inclined plate 11 and a left straight plate 12, and the right side plate 3 comprises a right inclined plate 31 and a right straight plate 32; the left side plate 1, the back plate 2 and the right side plate 3 form a flat-bottom U-shaped structure, the top of the flat-bottom U-shaped structure is provided with the left inclined plate 11 and the right inclined plate 31, and the left inclined plate 11 and the right inclined plate 31 form an inverted V-shaped structure; one side of the left inclined plate 11 is abutted against the opening of the inner chamber 001, and the other side of the left inclined plate is connected with the left straight plate 12; one side of the right inclined plate 31 is abutted to the opening of the inner chamber 001, and the other side of the right inclined plate 31 is connected with the right straight plate 32; the left side plate 1, the back plate 2 and the right side plate 3 are all provided with vent holes; the heating bag is arranged between the inner chamber 001 of the vacuum oven and the circulating air duct and comprises a middle partition plate 4 and heating bag modules 5 symmetrically arranged on two sides of the middle partition plate 4; a vent hole is formed in the middle of the back plate 2, and the middle partition plate 4 is arranged in the middle of the back plate 2 and connects the back surface of the back plate 2 with the back surface of the inner side of the inner chamber 001; the heating bag module 5 comprises a heating bag shell 51, a heating tube group 52 and a fan 53, wherein an air inlet 511 and an air outlet 512 are respectively formed at two ends of the heating bag shell 51, the air inlet 511 faces the middle partition plate 4, the fan 53 is installed on the air inlet 511, and the air outlet 512 faces a side wall air duct formed by the left side plate 1 or the right side plate 3 and the inner side of the inner chamber 001; the heat generation pipe group 52 is installed inside the heat generation pack case 51 between the air inlet 511 and the air outlet 512. Through the arrangement of the circulating air duct and the heating bag, after the heating tube group 52 generates heat, the heat is blown out from the left side plate 1 and the right side plate 3 through the fan 53, the heat continuously reaches each position of the inner chamber from the left inclined plate 11, the left straight plate 12, the right inclined plate 31 and the right straight plate 32, and enters the fan 53 again from the back plate 2 to form heat circulation.

While the present invention has been described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.