JP3157330B2 - Smoke exhaust system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a smoke exhaust device for exhausting smoke from a low-frequency melting furnace containing molten metal used in, for example, sand casting.

[0002]

2. Description of the Related Art Conventionally, there is a dust collecting device as described in Japanese Utility Model Laid-Open No. Sho 62-1725. That is, a transport duct connected to a dust collector having a suction blower, a suction duct connected to the transport duct and facing each of a plurality of dust generating facilities, and a valve mechanism provided in each of the suction ducts to open and close each suction duct. The driving state of each of the dust generating facilities described above is detected, and as the number of stopped dust generating facilities increases, the rotational speed of the suction blower is reduced and the suction duct is provided in the suction duct facing the stopped dust generating facilities. And a control mechanism for closing the valve mechanism.

According to this conventional apparatus, the number of rotations of a single suction blower is reduced and the valve mechanism is controlled in accordance with the number of stopped dust generating facilities, so that the capacity of the suction blower is effectively utilized. While there is an advantage that the energy consumption of the suction blower can be suppressed, there are the following problems.

That is, since the above-mentioned dust collecting apparatus merely controls the number of rotations of the suction blower in accordance with only the number of stopped dust generating facilities, this conventional apparatus is used, for example, for low-frequency melting and melting of molten metal. When applied to a device that collects smoke generated from a furnace, this low-frequency melting furnace has a different amount of smoke generation depending on both the operation / stop state and the opening / closing state of the furnace lid, so that the above-described conventional apparatus is not sufficient. There was a problem that it was not possible to perform a proper control.

[0005]

The invention according to claim 1 of the present invention is based on a smoke generation means based on a smoke generation state corresponding to the operation / stop state of a plurality of molten metal storage furnaces and the open / close state of the furnace lid. It is an object of the present invention to provide a smoke exhaust device capable of performing sufficient control by controlling the smoke recovery capacity and suppressing a decrease in the temperature of the molten metal in the molten metal storage furnace.

The invention according to claim 2 of the present invention, in addition to the object of the invention according to claim 1, uses a ring hood disposed along the outer peripheral edge of the furnace lid, thereby greatly increasing the smoke recovery capacity. It is an object of the present invention to provide a smoke exhaust device capable of achieving significant improvement.

[0007]

According to a first aspect of the present invention, there is provided a smoke exhaust device for exhausting smoke generated from a molten metal storage furnace, comprising a plurality of molten metal storage furnaces and each of the molten metal storage furnaces. A plurality of smoke recovery means for recovering smoke generated from each of these molten metal storage furnaces, a smoke recovery passage communicating each of the smoke recovery means and a single smoke discharge means, A variable means for varying the smoke recovery capacity, a distribution means interposed in the smoke recovery passage for distributing the smoke recovery capacity, a first detection means for detecting the operation / stop state of each of the molten metal storage furnaces, Second detection means for detecting the open / closed state of the furnace lid in the molten metal storage furnace; required amount calculation means for calculating the total required capacity required for smoke recovery based on the first and second detection means; A plurality of molten metal storage furnaces based on the first and second detection means; Ratio calculating means for calculating the ratio of the collecting capacity, and control means for controlling the smoke exhaust means via the variable means based on the required amount calculating means and driving the distribution means based on the ratio calculating means. Characterized in that it is a smoke exhaust device provided with:

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the ring hood is provided such that the smoke recovery means is disposed along the outer peripheral edge of the furnace lid of the molten metal storage furnace. Characterized in that it is a smoke exhaust device constituted by:

[0009]

According to the first aspect of the present invention, as shown in the claim correspondence diagram of FIG. 8, the first detecting means P1 detects the operation / stop state of the plurality of molten metal storage furnaces P2 and P3. The second detecting means P4 is connected to the plurality of molten metal storage furnaces P described above.
The open / closed state of the furnace lids P5 and P6 in P2 and P3 is detected. The required amount calculating means P7 calculates the total required capacity required for smoke recovery based on the output from each of the detecting means P1 and P4, while the ratio calculating means P8 calculates the output from each of the detecting means P1 and P4. Based on the above, the ratio of the smoke recovery capacity required for the plurality of molten metal storage furnaces P2 and P3 is calculated. Then, the control means P9 controls the smoke exhaust means P1 with the minimum necessary control force that satisfies the above-mentioned all required capabilities via the variable means P10.
1 and drive the distribution means P12 and P13 in accordance with the above ratio.

As a result, the smoke generated from the plurality of molten metal storage furnaces P2 and P3 is in operation, in the stopped state, and in the furnace lids P5 and P3.
The smoke collection means P14 and P15 and the smoke collection passage P16 collect the smoke into a single smoke exhaust means P11 with the minimum necessary capacity for the smoke collection corresponding to the open / close state of No. 6.

As described above, the above-mentioned control means controls the smoke collection capability of the smoke exhaust means based on the smoke generation state corresponding to the operation and stop states of the plurality of molten metal storage furnaces and the open / close state of the furnace lid. Sufficient control can be performed, and when the furnace lid is closed, the smoke recovery capability for the molten metal storage furnace is controlled so as to be small, so that there is an effect that a decrease in the temperature of the molten metal in the molten metal storage furnace can be suppressed. .

According to the second aspect of the present invention,
In addition to the effect of the first aspect of the present invention, since the above-mentioned smoke recovery means is constituted by a ring hood provided along the outer peripheral edge of the furnace lid of the molten metal storage furnace, it is possible to greatly improve the smoke recovery capacity. There is an effect that can be done.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a system diagram showing an entire sand mold casting apparatus provided with a smoke exhaust device according to the present invention. In FIG. 1, a static pressure molding machine 1 for molding a mold and gas vent holes are formed in a sand mold molded corresponding to an upper mold and a lower mold. Drilling machine 2 for punching, reversing device 3 for reversing only the upper die,
Sand cutter 4 for removing sand fragments on the surface of the sand mold, core setting device 5 for disposing cores in the sand mold as required, and weight for pressing the sand mold in advance because the sand mold expands due to the pressure during pouring. A setting device 6 and an automatic pouring machine 7 for automatically pouring molten metal into a cavity formed in a sand mold are provided.
7 are arranged substantially in a straight line from left to right as viewed from the plane, and the part after the automatic pouring is referred to as a turning point 8, and this turning point 8 is located from the right to the left as viewed from the plane. A relatively long in-frame cooling line 9 is connected.

A punching-up device 11 for extracting a sand mold with a built-in casting from a casting flask is provided at a release station 10 set at a stage next to the terminal end of the in-frame cooling line 9. Oscillate conveyor 1 in the next stage
2, a drum shaker 13 for separating sand and casting (product) is provided.

Further, an oscillating conveyor 14 is provided at the next stage of the above-mentioned drum shaker 13, and a rotary screen 1 is provided from the lower part of the sand falling port of the oscillating conveyor 14.
5 to convey the sand in the direction of the arrow a,
The product taken out from the product outlet of the above-mentioned oscillation conveyor 14 is transferred to an overhead conveyor 16 having a hanger.
To convey in the direction of arrow b.

On the right side of the above automatic pouring machine 7, for example, 2
The low-frequency melting furnaces 17A and 17B are provided, and smoke generated from the first and second low-frequency melting furnaces 17A and 17B is sucked by a suction fan 19 through a smoke collection duct 18. .

Each of the low-frequency melting furnaces 17A and 17B described above
Tracks 20 and 20 are laid between the front of the machine and the automatic pouring machine 7, and a moving carriage 21 that moves on these tracks 20 and 20
The ladle 22 is placed on top of the partition wall 23, and as shown by phantom lines in FIG.
It is surrounded by 4.

By the way, each of the above-mentioned low-frequency melting furnaces 17A, 17A,
The smoke exhaust device that collects and emits the smoke generated from 17B is configured as shown in FIG. 2, FIG. 3, and FIG.

That is, the low-frequency melting furnaces 17A, 17A,
Ring hoods 26, 26 are arranged along the outer peripheral edges of the respective furnace lids 25, 25 in 17B, and these ring hoods 26, 26 have communication ducts 27, 27 and a swivel, for example, composed of heat-resistant flexible ducts. (Swivel) Independent recovery duct 29,2 via 28,28
9 is connected in communication with the upstream end of each of these independent collection ducts 2.
The downstream portions 9 and 29 are joined to form a collecting portion 30, and the collecting portion 30 and the suction portion of the suction fan 19 are connected by a single common collection duct 31.

Here, the above-mentioned smoke collecting duct 18 is composed of independent collecting ducts 29, 29 and a common collecting duct 31, while the above-mentioned suction fan 19 has a fan motor 3
2 is transmitted via a driving pulley 33 fitted to the rotation shaft of the fan motor 32, a belt 34, and a driven pulley 35 on the fan side.

The above-mentioned swivels 28, 28 are disposed at or near the tilting fulcrum of the low-frequency melting furnaces 17A, 17B, while the low-frequency melting furnaces 17A, 17B are provided with a melting chamber 36. And a furnace cover 25, a tilting cylinder, and an energizing coil (not shown). When an electric current is supplied to the energizing coil, an induced current is generated in the molten metal (material) in the furnace. Then, the material is melted by Joule heat to form the molten metal M.

Further, each of the low-frequency melting furnaces 17A, 17
First and second air discharge devices 40, 41 for forcibly flowing smoke to the tap holes 39, 39 at the time of tapping are attached to the upper surfaces of the furnace bodies 38, 38 that are tilted integrally with B. .

The orbit 2 of each of the low-frequency furnaces 17A and 17B described above.
A frame 42 is erected on the opposite side of the frame
The suction fan 43 that sucks and collects smoke from the hot water
43 (however, only one is shown in the drawing), and at the time of tilting of each of the low-frequency melting furnaces 17A, 17B (see FIG. 4), above the tap holes 39, 39 and the movable carriage 21.
Opposite to the upper ladle 22, the smoke collection hoods 44, 44
Are arranged, and these smoke collection hoods 44, 44 are fixed to the above-mentioned frame 42.

The communication ports 45, 45 of the smoke collecting hoods 44, 44 and the suction portions of the suction fans 43, 43 are connected to each other via communication ducts 46, 46, and the suction fans 43, 43 are connected to each other. , 43 are provided at the discharge section.
7 is connected.

On the other hand, a single suction fan 1 is provided inside the independent collecting ducts 29, 29 in the above-mentioned smoke collecting duct 18.
9 as the distribution means for distributing the smoke recovery capacity
A valve 48 and a second valve 49 are separately mounted, and these valves 48 and 49 are connected to the first and second actuators 5 respectively.
It is configured to open and close at 0, 51 (see FIG. 6).

The above-described first and second air discharge devices 4
Numerals 0, 41 form air curtains 52, 53 (see FIG. 5) at the time of tapping and force the smoke generated at the time of tapping to flow toward the smoke collecting hoods 44, 44. The pneumatic circuit 53 is configured, for example, as shown in FIG. That is, an aftercooler 57, an air pressure tank 58, and a main line filter 5 are connected to a discharge line 56 of an air compressor 55 driven by a motor 54.
9. The respective air lines 61 and 62 are connected via the dryer 60, and the respective air lines 61 and 62 are connected to the respective air discharge devices 40 and 41, while the aforementioned air pressure tank 58 and the main line filter 59 are connected. The motor 54 is configured to be controlled via the pressure switch 63 with the air pressure between the motor 54 and the motor 54. It should be noted that a solenoid on-off valve is provided in each of the air lines 61 and 62 as required.

FIG. 6 shows a control circuit of the smoke exhaust device,
Reference numeral 70 denotes a first power switch 64 for detecting the operation / stop state of the first low frequency melting furnace 17A, and a second low frequency melting furnace 17B.
A second power switch 65 for detecting the operation / stop state of the
Outputs of a first limit switch 66 for detecting the open / closed state of the furnace lid 25 in the first low-frequency melting furnace 17A and a second limit switch 67 for detecting the open / closed state of the furnace lid 25 in the second low-frequency melting furnace 17B. ROM based on signal
The first and second actuators 50 and 51, the inverter 69 as a frequency conversion device, and the first and second air discharge devices 40 and 41 in accordance with the program stored in the storage device 68.
, And the RAM 71 stores necessary data, maps, and the like.

Here, the CPU 70 described above controls the minimum power required for smoke recovery based on the outputs of the first and second power switches 64 and 65 and the outputs of the first and second limit switches 66 and 67. Requested amount calculating means for calculating the total required capacity (refer to the third step S3 in the flowchart shown in FIG. 7)
And ratio calculating means for calculating the ratio of the smoke collection capacity of the two low-frequency melting furnaces 17A and 17B based on the outputs of the power switches 64 and 65 and the limit switches 66 and 67 (flow chart shown in FIG. 7). 4th step S4
), And variably controls the number of rotations of the fan motor 32 or the air flow rate by the suction fan 19 via an inverter 69 as a variable means based on the calculation result of the required amount calculation means. Based on the result, it also serves as a control unit (see the fifth step S5 in the flowchart shown in FIG. 7) for controlling the opening and closing of the first valve 48 and the second valve 49 by the distribution unit.

In this embodiment, the set frequency of the inverter 69 by operating and stopping the low-frequency melting furnaces 17A and 17B, and opening and closing the furnace lid 25, and the respective valves 48 and
The open / close state of 49 and the air volume are set as shown in the following [Table 1], and these set contents may be stored as a map in the RAM 71 described above.

[0030]

[Table 1]

The operation of the smoke exhaust device configured as described above will be described in detail below with reference to the flowchart of FIG.

In a first step S1, the CPU 70 reads the operating state of each of the low-frequency melting furnaces 17A and 17B based on signals from the first and second power switches 64 and 65.

Next, in a second step S2, the CPU 70 reads the open / closed state of the furnace lids 25, 25 in each of the low frequency melting furnaces 17A, 17B based on the signals from the first and second limit switches 66, 67. Put in.

Next, in a third step S3, the CPU 70 operates and stops each of the low-frequency melting furnaces 17A and 17B, as well as the furnace lids 25 and 25 in each of the low-frequency melting furnaces 17A and 17B.
The required capacity (required minimum value) required to recover the smoke generated from the two low-frequency melting furnaces 17A and 17B is calculated in accordance with the open / closed state, that is, the smoke generation state.

Next, in a fourth step S4, the CPU 70 turns ON / OFF signals from the power switches 64, 65 and ON / OFF signals from the limit switches 66, 67.
Based on the OFF signal, two low-frequency melting furnaces 17A,
Calculate the 17B smoke recovery capacity ratio. That is, a distribution ratio is determined as to how to distribute the total required capacity corresponding to the above-described minimum value (specifically, the air volume) to the two low-frequency melting furnaces 17A and 17B.

Next, in a fifth step S5, the CPU 70 controls the drive of the fan motor 32 via the inverter 69 in accordance with the total required capacity as a necessary minimum value, and in accordance with the distribution ratio described above. Each actuator 50,
The first valve 48 and the second valve 49 are controlled to open and close via 51.

The above description will be described in more detail based on Table 1 described above.
When the low-frequency melting furnace 17A is operating, the furnace lid 25 of the melting furnace 17A is open, the second low-frequency melting furnace 17B is operating, the furnace lid 25 of the melting furnace 17B is open, and all switches shown in FIG. When the switches 64, 65, 66, and 67 are ON, the CPU 70 sets the frequency of the inverter 69 to 60 Hz, the air volume corresponding to the total required capacity to 350 m ³ / min, and the distribution ratio by the valves 48 and 49 to 50:50. While driving the motor 32, the first
The valve 48 and the second valve 49 are both opened.

The smoke generated from each of the low-frequency melting furnaces 17A and 17B under the above-described conditions corresponding to the above-described material charging time is supplied to the ring hood 26, the communication duct 27, and the swivel 2
8, after being collected by the suction fan 19 through the independent collection duct 29, the collecting part 30, and the common collection duct 31, smoke is discharged from the discharge part thereof through the smoke discharge duct 72 by the rotation of the impeller in the suction fan 19. Is done.

On the other hand, as shown in the sixth row from the top of Table 1,
When the first low-frequency melting furnace 17A is in the operating state, the furnace lid 25 of the first melting furnace 17A is closed, and the second low-frequency melting furnace 17B is stopped,
When only the first power switch 64 shown in FIG. 6 is ON,
The CPU 70 sets the frequency of the inverter 69 to 30 Hz, the air volume corresponding to the total required capacity to 100 m ³ / min,
The fan motor 32 is driven while the distribution ratio of the actuators 50 and 5 is set to 100: 0.
1, one first valve 48 is opened and the other second valve 48 is opened.
The first low-frequency melting furnace 17 in operation is closed by closing the valve 49.
Smoke generated from A is transmitted to each element 26, 27, 28, 29,
Collect and exhaust via 30, 30, 19, 72.

In the case of other various conditions, the above Table 1 was used.
The frequency of the inverter 69 and the minimum required airflow are set as shown by
While the valve 49 is controlled to open and close, at the time of tapping, the air discharge devices 40 and 41 corresponding to the low-frequency melting furnaces 17A and 17B during tapping are driven as shown in FIG.
The air curtains 52 and 53 are formed by air discharged from the slit-shaped air discharge ports of the air curtain 5.
Smoke generated from the low-frequency melting furnaces 17A, 17B and the ladle 22 during tapping at 2 and 53 is supplied to the smoke recovery hoods 44 and 4, respectively.
4 and the smoke suctioned and collected by the smoke collection hood 44 by the rotation of the suction fan 43.
Exhaust smoke through 6, 43, 47.

As described above, the plurality of low frequency melting furnaces 17A, 1
7B based on the smoke generation state corresponding to the operation / stop state of 7B and the open / close state of the furnace lids 25 in each of the melting furnaces 17A and 17B (see the fifth step S5 in the flowchart shown in FIG. 7). Controls the number of revolutions of the fan motor 32 to a necessary minimum via the inverter 69, so that the energy consumption of the smoke exhaust unit can be reduced while effectively utilizing the capacity of the smoke exhaust unit including the suction fan 19 and the fan motor 32. Of course, there is an effect that sufficient control corresponding to the smoke generation state that is changed by two parameters can be performed.

As is clear from the above-mentioned Table 1 and the flow chart of FIG. 7, when the furnace lid 25 is closed, the low-frequency melting furnaces 17A and 17B are controlled so as to reduce the smoke recovery capacity. Low frequency melting furnace 17A,
There is an effect that the temperature drop of the molten metal M in 17B can be suppressed.

In addition, when the above-described ring hood 26 is used as the smoke collecting means, the smoke collecting capacity can be greatly improved, and the excess space above the low-frequency melting furnaces 17A and 17B can be provided inside the furnace. There is an effect that the material can be effectively used as a space for arranging a material charging conveyor for material charging.

In correspondence between the configuration of the present invention and the above-described embodiment, the molten metal storage furnace of the present invention corresponds to the first and second low frequency melting furnaces 17A and 17B of the embodiment. The smoke collecting means corresponds to the ring hood 26, the smoke exhausting means corresponds to the suction fan 19 and the fan motor 32, the smoke collecting passage corresponds to the smoke collecting duct 18, and the distributing means corresponds to the first valve 48 and Corresponding to the second valve 49,
The first detecting means corresponds to the first power switch 64 and the second power switch 65, the second detecting means corresponds to the first limit switch 66 and the second limit switch 67,
The variable means corresponds to the inverter 69, the required amount calculation means corresponds to the third step S3 controlled by the CPU 70,
The ratio calculating means performs the fourth step S under the control of the CPU 70.
4, the control means corresponds to the fifth step S5 under the control of the CPU 70, but the present invention is not limited to only the configuration of the above-described embodiment.

[Brief description of the drawings]

FIG. 1 is a system diagram of a sand casting device provided with a smoke exhaust device of the present invention.

FIG. 2 is a plan view showing the smoke exhaust device of the present invention.

FIG. 3 is a side view of FIG. 2;

FIG. 4 is an explanatory view at the time of tapping.

FIG. 5 is a pneumatic circuit diagram showing an air pressure source for the air discharge device.

FIG. 6 is a control circuit block diagram.

FIG. 7 is a flowchart showing smoke control.

FIG. 8 is a diagram corresponding to claims.

[Explanation of symbols]

 17A, 17B: Low frequency melting furnace 18: Smoke collection duct 19: Suction fan 25 ... Furnace lid 26 ... Ring hood 32 ... Fan motor 48, 49 ... Valve 64, 65 ... Power switch 66, 67 ... Limit switch 69 ... Inverter S3 ... Requested amount calculation means S4 ... Ratio calculation means S5 ... Control means

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-58-29567 (JP, A) JP-A-4-32691 (JP, A) JP-A-62-144728 (JP, A) JP-A-62-144728 56775 (JP, A) JP-A-62-56774 (JP, A) JP-A-52-103305 (JP, A) JP-A-3-24361 (JP, U) JP-A-1-143365 (JP, U) Japanese Utility Model Application Showa 54-136322 (JP, U) Japanese Utility Model Application Showa 55-77562 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22D 43/00 F27D 17/00 104

Claims (2)

(57) [Claims] 1. A smoke exhaust device for exhausting smoke generated from a molten metal storage furnace, comprising: a plurality of molten metal storage furnaces; and a plurality of the molten metal storage furnaces. A plurality of smoke collecting means to be collected, a smoke collecting passage communicating each of the smoke collecting means and a single smoke exhausting means, a variable means for varying a smoke collecting ability of the smoke exhausting means, and a smoke collecting passage. Distribution means interposed for distributing the smoke collection capacity, first detection means for detecting the operation / stop state of each of the molten metal storage furnaces, and second detection for detecting the open / closed state of the furnace lid in each of the molten metal storage furnaces Means, required amount calculating means for calculating the total required capacity required for smoke recovery based on the first and second detecting means, and a plurality of molten metal storages based on the first and second detecting means. A ratio calculating means for calculating the ratio of the smoke recovery capacity of the furnace; Controls the flue gas section through the variable means based on the amount computing means, flue gas and control means for driving the dispensing means based on said ratio calculation means. 2. The smoke exhaust device according to claim 1, wherein said smoke collecting means is constituted by a ring hood disposed along an outer peripheral edge of a furnace lid of said molten metal storage furnace.