CN112629254A

CN112629254A - Melting furnace for metal casting

Info

Publication number: CN112629254A
Application number: CN202011303606.4A
Authority: CN
Inventors: 吴慧东
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-11-19
Filing date: 2020-11-19
Publication date: 2021-04-09

Abstract

The invention discloses a melting furnace for metal casting, which comprises a furnace body, wherein a feed inlet is formed in one side of the upper part of the furnace body, a motor is fixedly arranged on one side of the feed inlet in the upper part of the furnace body, an air pump is fixedly arranged on one side of the motor in the upper part of the furnace body, a plurality of stirring columns are fixedly arranged on the outer surface of a rotating shaft, a crushing roller is rotatably arranged in a crushing groove, a rotating gear is fixedly arranged at one end, positioned in a gear bin, of the crushing roller, a plurality of first screening openings, a second discharge pipe and a third screening opening are formed in the upper side of a first discharge material on a partition plate, a supporting gear is fixedly arranged at the top end of a vertical shaft, a friction plate is sleeved outside the vertical shaft in a sliding mode, 2 weight sensors are fixedly arranged on the. The invention can make the metal materials enter the electric heating barrel in sequence from big to small, thereby being beneficial to improving the melting efficiency.

Description

Melting furnace for metal casting

Technical Field

The invention relates to the technical field of melting furnaces, in particular to a melting furnace for metal casting.

Background

The metal melting furnace is a common metal processing device, quickly melts metal through electric heating or other heating modes, and is widely applied to the casting industry. Traditional melting furnace function singleness lacks necessary sieving mechanism and reducing mechanism, makes the metal material of variation in size mix at will in the stove, and the uneven being heated of each metal material often appears the metal of the bottom in the stove and melts the back upper portion metal and still does not melt, need reheating, causes the waste of energy.

Disclosure of Invention

The present invention is directed to a melting furnace for metal casting, which solves the problems set forth above in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: a melting furnace for metal casting comprises a furnace body, wherein a feed inlet is formed in one side of the upper portion of the furnace body, a motor is fixedly arranged on one side of the feed inlet in the upper portion of the furnace body, an air pump is fixedly arranged on one side of the motor in the upper portion of the furnace body, an air inlet end of the air pump is communicated with an air inlet pipe, the air inlet pipe penetrates into the furnace body downwards, an output shaft of the motor penetrates into the furnace body, a rotating shaft is fixedly arranged at the bottom of the output shaft of the motor, a plurality of stirring columns are fixedly arranged on the outer surface of the rotating shaft, crushing grooves are formed in the stirring columns, crushing rollers are rotatably arranged in the crushing grooves, spiral crushing blades are fixedly arranged on the outer walls of the crushing rollers, gear bins are formed in the rotating shaft, the crushing rollers penetrate into the gear bins, rotating gears are fixedly arranged at, the separator is communicated with a first discharging pipe, one side of the first discharging pipe on the separator is communicated with a second discharging pipe, one side of the second discharging pipe on the separator is communicated with a third discharging pipe, the first discharging pipe, the second discharging pipe and the third discharging pipe are symmetrically distributed around the center of the separator, a plurality of first screening openings are formed in the upper side of the first discharging pipe on the separator, a plurality of second screening openings are formed in the upper side of the second discharging pipe on the separator, a plurality of third screening openings are formed in the upper side of the third discharging pipe on the separator, a supporting cylinder is fixedly arranged on the inner side of a rotating shaft in the middle of the separator, a vertical shaft is rotatably arranged in the supporting cylinder, a supporting gear is fixedly arranged at the top end of the vertical shaft, the supporting gear is meshed with a rotating gear, a friction plate is sleeved outside the vertical shaft in a sliding manner, guide grooves, the two sides of the friction plate are respectively fixedly connected with the sliding block, one side of a vertical shaft in the supporting cylinder is fixedly provided with an air cylinder, the top end of the air cylinder is fixedly connected with the friction plate, the air cylinder is communicated with an external air source, the right side of the vertical shaft in the supporting cylinder is fixedly provided with a supporting sleeve, the two ends of the supporting sleeve are respectively fixedly connected with the friction plate and the partition plate, the lower ends of the first discharging pipe, the second discharging pipe and the third discharging pipe are respectively and fixedly provided with a first valve, a second valve and a third valve, the bottom parts of the first valve, the second valve and the third valve are respectively communicated with discharging pipes, one side of each discharging pipe is respectively communicated with a branch pipe, the branch pipes are respectively communicated with an air valve, the branch pipes penetrate through the furnace body to be communicated with the lower side of the air outlet end of the air pump, the partition plate in the furnace body is uniformly provided with a heat preservation, the fixed electric heating bucket that is provided with in one side of the bottom heat preservation insulating layer of furnace body, the fixed apron that is provided with in upside of the electric heating bucket in the furnace body, the discharging pipe runs through the apron downwards respectively, the molten liquid export has been seted up to the furnace body bottom, the molten liquid is provided with the drain pipe in the export is fixed, the furnace body external fixation is provided with the controller, the controller respectively with motor, air pump, weighing transducer and cylinder electric connection.

Preferably, the number of the stirring columns is 3, and the stirring columns are uniformly and symmetrically distributed around the rotating shaft.

Preferably, the first valve, the second valve and the third valve are electromagnetic valves, and the first valve, the second valve and the third valve are respectively electrically connected with the controller.

Preferably, the air valves are all electromagnetic valves, the model of the air valve is LD7220, and the air valves are respectively and electrically connected with the controller.

Preferably, the liquid outlet pipe is connected with a discharge valve.

Preferably, a fixing ring is sleeved on one end, close to the cover plate, of the discharge pipe, and the fixing ring is fixedly connected with the inner wall of the furnace body.

Preferably, the number of the first screening openings, the second screening openings and the third screening openings is not less than 6, and the first screening openings, the second screening openings and the third screening openings are respectively and uniformly distributed on the surfaces of the first discharge pipe, the second discharge pipe and the third discharge pipe.

Preferably, the first screening opening, the second screening opening and the third screening opening are arranged from large to small in size.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention is provided with a first screening opening, a second screening opening and a third screening opening, the first screening opening, the second screening opening and the third screening opening are positioned in the same plane and sequentially reduced in size, the trouble of arranging a plurality of layers of screening nets is saved, metal materials are sequentially put into an electric heating barrel according to the size by controlling the opening of a corresponding first valve, a second valve and a third valve for heating and melting, therefore, the metal materials with larger volume enter the electric heating barrel and are distributed at the bottommost layer, and by analogy, the metal materials with moderate volume are distributed at the middle part after falling into the electric heating barrel, and the metal materials with the minimum volume are distributed at the topmost layer of the electric heating barrel finally, so that the metal materials with the maximum volume are directly contacted with the bottom surface of the electric heating barrel, the heating area is the maximum, the metal materials are easier to melt, the heating efficiency is improved, and the metal materials in the heated barrel are fully melted, the condition that the upper metal is still not melted after the metal at the bottom is melted due to uneven heating caused by different distribution positions of metal materials with different volumes is avoided, and the energy consumption is increased;

2. the invention is also provided with the weight sensor, which can detect the amount of the residual metal material on the partition board so as to judge whether the metal material is completely put into the heating barrel;

3. the metal material crushing device is provided with the stirring column and the crushing roller at the same time, when the metal material which cannot pass through the first screening opening, the second screening opening and the third screening opening is left on the upper part of the partition plate and crushed, the air cylinder is started through the controller, the friction plate is jacked up after the air cylinder is started, the friction plate moves to drive the sliding block to slide in the guide groove, the support sleeve is stretched, the air cylinder tightly presses the friction plate to the bottom of the support gear, the support gear does not rotate any more after receiving pressure, when the crushing roller rotates along with the stirring column, the rotating gear rotates around the support gear under the action of a reaction force, the rotating gear rotates to drive the crushing roller to rotate, the crushing roller rotates to drive the crushing blade to rotate, namely, the crushing roller also rotates along with the rotating shaft, and the metal material outside is crushed through the crushing;

4. the branch pipes are arranged at the same time, the air pump is started through the controller at the moment, one or more of the three air valves are opened at the same time, the specific opening quantity is determined by the controller according to the weight of the residual metal material measured by the weight sensor and is determined according to the quantity of the metal powder in the furnace, the metal powder in the air is sucked out and sent into the electric heating barrel through the corresponding branch pipes to be melted, and therefore the utilization rate of the metal material is improved.

Drawings

FIG. 1 is a sectional view showing a front structure of a melting furnace for metal casting according to the present invention;

FIG. 2 is a schematic top view of a melting furnace for casting metal according to the present invention;

FIG. 3 is a schematic side view of a melting furnace for metal casting according to the present invention;

FIG. 4 is a cross-sectional view taken along line A-A of FIG. 1 in accordance with the present invention;

FIG. 5 is a cross-sectional view taken along line B-B of FIG. 1 in accordance with the present invention;

FIG. 6 is an enlarged view of the structure at A in FIG. 1 according to the present invention;

FIG. 7 is an enlarged view of the structure at B in FIG. 1 according to the present invention.

In the figure: 100. a feed inlet; 101. a feed inlet; 102. a motor; 103. an air pump; 104. an air inlet pipe; 105. a rotating shaft; 106. a stirring column; 107. a crushing tank; 108. a crushing roller; 109. crushing the leaves; 110. a gear chamber; 111. a rotating gear; 112. a partition plate; 113. a second discharge pipe; 114. a third discharge pipe; 115. a first discharge pipe; 116. a first screening port; 117. a second screening port; 118. a third screening port; 119. a support cylinder; 120. a vertical axis; 121. a support gear; 122. a friction plate; 123. a cylinder; 124. a support sleeve; 125. a first valve; 126. a second valve; 127. a third valve; 128. a material receiving pipe; 129. a branch pipe; 130. an air valve; 131. a heat insulation layer; 132. a weight sensor; 133. an electrical heating barrel; 134. a cover plate; 135. a liquid outlet pipe; 136. and a controller.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below 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 of the 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. 1-7, the present invention provides a technical solution: a melting furnace for metal casting comprises a furnace body 100, a feed inlet 101 is arranged on one side of the upper part of the furnace body 100, a motor 102 is arranged on one side of the feed inlet 101 on the upper part of the furnace body 100 through a bolt, an air pump 103 is arranged on one side of the motor 102 on the upper part of the furnace body 100 through a bolt, an air inlet pipe 104 is communicated with an air inlet end of the air pump 103, the air inlet pipe 104 penetrates downwards into the furnace body 100, an output shaft of the motor 102 penetrates into the furnace body 100, a rotating shaft 105 is arranged at the bottom of the output shaft of the motor 102 through a coupler, a plurality of stirring columns 106 are welded on the outer surface of the rotating shaft 105, crushing grooves 107 are arranged in the stirring columns 106, crushing rollers 108 are rotatably arranged in the crushing grooves 107, spiral crushing blades 109 are welded on the outer walls of the crushing rollers 108, a gear bin 110 is arranged, a partition plate 112 is welded and installed on the lower side of a stirring column 106 in a furnace body 100, a first discharge pipe 115 is communicated with the partition plate 112, a second discharge pipe 113 is communicated with one side of the first discharge pipe 115 on the partition plate 112, a third discharge pipe 114 is communicated with one side of the second discharge pipe 113 on the partition plate 112, the first discharge pipe 115, the second discharge pipe 113 and the third discharge pipe 114 are symmetrically distributed around the center of the partition plate 112, a plurality of first screening openings 116 are formed in the upper side of the first discharge pipe on the partition plate 112, a plurality of second screening openings 117 are formed in the upper side of the second discharge pipe 113 on the partition plate 112, a plurality of third screening openings 118 are formed in the upper side of the third discharge pipe 114 on the partition plate 112, a support cylinder 119 is welded and installed on the inner side of a rotating shaft 105 in the middle of the partition plate 112, a vertical shaft 120 is rotatably installed in the support cylinder 119, a support, guide grooves are formed in two sides of a supporting cylinder 119, sliding blocks are slidably mounted in the guide grooves, two sides of a friction plate 122 are respectively connected with the sliding blocks in a welding manner, an air cylinder 123 is mounted on one side of a vertical shaft 120 in the supporting cylinder 119 through a bolt, the top end of the air cylinder 123 is connected with the friction plate 122 in a welding manner, the air cylinder 123 is communicated with an external air source, a supporting sleeve 124 is mounted on the right side of the vertical shaft 120 in the supporting cylinder 119 in a welding manner, two ends of the supporting sleeve 124 are respectively connected with the friction plate 122 and a partition plate 112 in a welding manner, a first valve 125, a second valve 126 and a third valve 127 are respectively mounted at the lower ends of a first discharging pipe 115, a second discharging pipe 113 and a third discharging pipe 114, material receiving pipes 128 are respectively communicated with the bottoms of the first valve 125, the second valve 126 and the third valve 127, a branch pipe 129 is respectively communicated with one side of each material receiving pipe 128, the utility model discloses a furnace body 100 inner partition 112 is located the downside and evenly installs heat preservation insulating layer 131 on the surface, 2 weight sensor 132 are installed through the bolt to heat preservation insulating layer 131 inner partition 112's downside, electric heating bucket 133 is installed in the welding of one side of furnace body 100's bottom heat preservation insulating layer 131, cover plate 134 is installed in the upside welding of electric heating bucket 133 in furnace body 100, material receiving pipe 128 runs through cover plate 134 downwards respectively, the melt outlet has been seted up to furnace body 100 bottom, the welded installation has drain pipe 135 in the melt outlet, controller 136 is installed through the bolt to furnace body 100 outside, controller 136 respectively with motor 102, air pump 103, weight sensor 132 and cylinder 123 electric connection.

The number of the stirring rods 106 is 3, and the stirring rods 106 are uniformly and symmetrically distributed around the rotating shaft 105.

The first valve 125, the second valve 126 and the third valve 127 are all solenoid valves, and the first valve 125, the second valve 126 and the third valve 127 are respectively electrically connected to the controller 136.

The first air valve 130, the second air valve 130 and the third air valve 130 are all electromagnetic valves, the model of the first air valve 130, the model of the second air valve 130 and the model of the third air valve 130 are LD7220, and the first air valve 130, the second air valve 130 and the third air valve 130 are respectively and electrically connected with the controller 136.

The liquid outlet pipe 135 is connected with a discharge valve.

One end of the material receiving pipe 128 close to the cover plate 134 is sleeved with a fixing ring, and the fixing ring is connected with the inner wall of the furnace body 100 through a bolt.

The number of the first sieve openings 116, the second sieve openings 117 and the third sieve openings 118 is not less than 6, and the first sieve openings 116, the second sieve openings 117 and the third sieve openings 118 are respectively and uniformly distributed at the upper parts of the first discharge pipe 115, the second discharge pipe 113 and the third discharge pipe 114.

The first, second and

third orifices

116, 117 and 118 are sized in a large to small array.

The working principle is as follows: when the metal material dissolving device is used, metal materials to be dissolved are added from the feeding hole 101, the metal materials enter the furnace body 100, the motor 102 is started, the motor 102 drives the rotating shaft 105 to rotate after rotating, the rotating shaft 105 drives the stirring column 106 to rotate, the stirring column 106 rotates to drive the metal materials on the partition plate 112 to rotate, the crushing roller 108 rotates along with the stirring column 106 when the stirring column 106 rotates, meanwhile, the rotating gear 111 is connected to the end part of the crushing roller 108, the rotating resistance of the crushing roller 108 in the circumferential direction is larger than the resistance of the supporting gear 121 to the rotating gear 111, therefore, when the crushing roller 108 rotates along with the stirring column 106, the supporting gear 121 rotates along with the rotating shaft 105 under the driving of the rotating gear 111, and because the partition plate 112 is provided with the first screening hole 116, the second screening hole 117 and the third screening hole 118 which are different in size, the metal materials sequentially pass through the first screening hole 116, the second, The second screening opening 117 and the third screening opening 118 screen the metal materials through the first screening opening 116, the second screening opening 117 and the third screening opening 118, the controller 136 controls the first valve 125 to open, the metal materials continuously fall from the first screening opening 116 and enter the electric heating barrel 133 through the material receiving pipe 128, the controller 136 automatically opens the second valve 126 after a certain time interval, the remaining metal materials fall from the second screening opening 117 and enter the electric heating barrel 133 through the material receiving pipe 128, after a certain time interval, the controller 136 opens the third valve 127, the metal materials after two times of screening fall from the third screening opening 118 into the material storage pipe and enter the electric heating barrel 133 through the material receiving pipe 128, the operator determines each time interval, and the metal materials are installed and stored in the controller 136, because the sizes of the first screening opening 116, the second screening opening 117 and the third screening opening 118 are gradually reduced, therefore, the metal material falling from the first screening opening 116 has a large volume, and since the first screening opening 116 is opened first, the metal material with a large volume is distributed at the bottommost layer after entering the electric heating barrel 133, and so on, the metal material with a moderate volume is distributed at the middle part after falling into the electric heating barrel 133, and the metal material with the minimum volume which falls at last is distributed at the uppermost layer of the electric heating barrel 133, so that the metal material with the largest volume is directly contacted with the bottom surface of the electric heating barrel 133, the heating area is largest, the metal material is easier to melt, the heating efficiency is improved, the metal material in the heated barrel is fully melted, the condition that the metal material at the bottom is not melted due to the fact that the metal materials with different volumes are distributed at different positions, and the energy consumption is increased;

the weight sensor 132 at the lower part of the partition 112 can detect the weight of the metal material at the upper part of the partition 112, when stirring and screening are performed for a certain period of time, the metal material of the electric heating barrel 133 which does not enter still remains on the partition 112, which indicates that the residual metal material has too large volume and cannot pass through the first screening opening 116, at this time, the controller 136 starts the air cylinder 123, the friction plate 122 is jacked up after the air cylinder 123 is started, the friction plate 122 moves to drive the sliding block to slide in the guide groove, the supporting sleeve 124 is stretched, the air cylinder 123 presses the friction plate 122 at the bottom of the supporting gear 121, at this time, the supporting gear 121 does not rotate after receiving pressure, when the crushing roller 108 rotates along with the stirring column 106, the rotating gear 111 rotates around the supporting gear 121 under the action of reaction force, the rotating gear 111 rotates to drive the crushing roller 108 to rotate, the crushing roller 108 rotates to drive the crushing blade, that is, the crushing roller 108 rotates along with the rotation shaft 105, and crushes the metal powder outside through the crushing blade 109 so that the size of the metal powder can pass through the first screening port 116, the second screening port 117 or the third screening port 118, and at the same time, the metal powder is splashed during the crushing process, at this time, the air pump 103 is started through the controller 136, one or more of the three air valves 130 are opened, the specific opening amount is determined by the controller 136 according to the weight of the remaining metal powder measured by the weight sensor, and is determined according to the amount of the metal powder in the furnace, the metal powder in the air is sucked out and sent into the electric heating barrel 133 through the corresponding branch pipe 129 to be melted, and therefore, the utilization rate of the metal material is improved.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A melting furnace for metal casting, includes furnace body (100), its characterized in that: a feed inlet (101) is formed in one side of the upper portion of the furnace body (100), a motor (102) is fixedly arranged on one side of the feed inlet (101) in the upper portion of the furnace body (100), an air pump (103) is fixedly arranged on one side of the motor (102) in the upper portion of the furnace body (100), an air inlet pipe (104) is communicated with an air inlet end of the air pump (103), the air inlet pipe (104) penetrates through the furnace body (100) downwards, an output shaft of the motor (102) penetrates through the furnace body (100), a rotating shaft (105) is fixedly arranged at the bottom of the output shaft of the motor (102), a plurality of stirring columns (106) are fixedly arranged on the outer surface of the rotating shaft (105), crushing grooves (107) are formed in the stirring columns (106), crushing rollers (108) are rotatably arranged in the crushing grooves (107), and spiral crushing blades (, a gear bin (110) is arranged in the rotating shaft (105), the grinding roller (108) penetrates into the gear bin (110), one end, located in the gear bin (110), of the grinding roller (108) is fixedly provided with a rotating gear (111), the lower side of the stirring column (106) in the furnace body (100) is fixedly provided with a partition plate (112), a first discharging pipe (115) is communicated with the partition plate (112), a second discharging pipe (113) is communicated with one side of the first discharging pipe (115) on the partition plate (112), a third discharging pipe (114) is communicated with one side of the second discharging pipe (113) on the partition plate (112), the first discharging pipe (115), the second discharging pipe (113) and the third discharging pipe (114) are symmetrically distributed around the center of the partition plate (112), a plurality of first screening openings (116) are formed in the upper side of the first discharging pipe on the partition plate (112), a plurality of second screening openings (117) are formed in the upper side of the second discharging pipe (113) on the partition plate (, a plurality of third screening openings (118) are formed in the upper side of a third discharge pipe (114) on the partition plate (112), a support cylinder (119) is fixedly arranged on the inner side of a middle rotating shaft (105) of the partition plate (112), a vertical shaft (120) is arranged in the support cylinder (119) in a rotating manner, a support gear (121) is fixedly arranged at the top end of the vertical shaft (120), the support gear (121) is meshed with a rotating gear (111), a friction plate (122) is sleeved on the outer sliding sleeve of the vertical shaft (120), guide grooves are formed in two sides of the support cylinder (119), a sliding block is arranged in the guide grooves in a sliding manner, two sides of the friction plate (122) are respectively and fixedly connected with the sliding block, an air cylinder (123) is fixedly arranged on one side of the vertical shaft (120) in the support cylinder (119), the top end of the air cylinder (123) is fixedly connected with the friction plate (, a supporting sleeve (124) is fixedly arranged on the right side of a vertical shaft (120) in the supporting cylinder (119), two ends of the supporting sleeve (124) are fixedly connected with a friction plate (122) and a partition plate (112) respectively, the lower ends of a first discharge pipe (115), a second discharge pipe (113) and a third discharge pipe (114) are fixedly provided with a first valve (125), a second valve (126) and a third valve (127) respectively, the bottoms of the first valve (125), the second valve (126) and the third valve (127) are communicated with discharge pipes (128) respectively, one side of each discharge pipe (128) is communicated with a branch pipe (129) respectively, the branch pipes (129) are communicated with an air valve (130) respectively, the branch pipes (129) penetrate through the furnace body (100) and are communicated with an air outlet end of an air pump (103), and heat-insulating layers (131) are uniformly arranged on the surface of the lower side of the partition plate (112) in the furnace body (100), the fixed 2 weight sensors (132) that are provided with of downside of baffle (112) in heat preservation insulating layer (131), one side of bottom heat preservation insulating layer (131) of furnace body (100) is fixed and is provided with electric heating bucket (133), the fixed apron (134) that is provided with of upside of electric heating bucket (133) in furnace body (100), discharging pipe (128) run through apron (134) downwards respectively, the melt export has been seted up to furnace body (100) bottom, the fixed drain pipe (135) that is provided with in the melt export, furnace body (100) external fixation is provided with controller (136), controller (136) respectively with motor (102), air pump (103), weight sensor (132) and cylinder (123) electric connection.

2. The melting furnace for metal casting according to claim 1, wherein: the number of the stirring columns (106) is 3, and the stirring columns (106) are uniformly and symmetrically distributed around the rotating shaft (105).

3. The melting furnace for metal casting according to claim 1, wherein: the first valve (125), the second valve (126) and the third valve (127) are all electromagnetic valves, and the first valve (125), the second valve (126) and the third valve (127) are respectively electrically connected with the controller (136).

4. The melting furnace for metal casting according to claim 1, wherein: the first air valve (130), the second air valve (130) and the third air valve (130) are all electromagnetic valves, the model numbers of the first air valve (130), the second air valve (130) and the third air valve (130) are LD7220, and the first air valve (130), the second air valve (130) and the third air valve (130) are respectively and electrically connected with the controller (136).

5. The melting furnace for metal casting according to claim 1, wherein: and a discharge valve is connected to the liquid outlet pipe (135).

6. The melting furnace for metal casting according to claim 1, wherein: one end of the material receiving pipe (128) close to the cover plate (134) is sleeved with a fixing ring, and the fixing ring is fixedly connected with the inner wall of the furnace body (100).

7. The melting furnace for metal casting according to claim 1, wherein: the quantity of first sieve opening (116), second sieve opening (117) and third sieve opening (118) is no less than 6, first sieve opening (116), second sieve opening (117) and third sieve opening (118) evenly distributed respectively in first discharging pipe (115), second discharging pipe (113) and third discharging pipe (114) upper portion.

8. The melting furnace for metal casting according to claim 1, wherein: the first screening opening (116), the second screening opening (117) and the third screening opening (118) are arranged in a size from large to small.