JP4329058B2 - Method of controlling kneaded sand conveying screw conveyor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a screw for conveying the kneaded sand that is used to molding the green sand mold - a method of controlling the conveyor equipment.
[0002]
[Prior art]
In general, kneaded sand for molding green sand molds is kneaded by adding clay and additives and water as a binder to silica sand, and has good adhesion because it has good moldability and mold retention. It is expensive. Conventionally, a belt conveyor has been widely used as a transport means for kneaded sand having such a high adhesion property. In recent years, a screw conveyor having an entire transport path in a sealed structure so as not to deteriorate the working environment. Are increasingly being used.
[0003]
However, when the kneaded sand is conveyed by a screw conveyor, the kneaded sand adheres to the screw, and when this adhesion grows, a significant decrease in conveying ability or a state where conveyance is impossible occurs. For this reason, powder conveyors intended to solve these problems have been disclosed in Japanese Patent Laid-Open Nos. 60-71426, 60-81918, and 2000-233817. ing.
[0004]
[Problems to be solved by the invention]
However, JP-A-60-71426 discloses that only the powder particles below the powder particle inlet are fluidized by the powder fluidizing gas, and the adhesion preventing effect is insufficient. Japanese Utility Model Laid-Open No. 60-81918 has only a slight gap at the base of the screw shaft, which is not a satisfactory solution. Further, JP-A-2000-233817 discloses a method for preventing clogging of powder particles, but there is a problem that the structure is complicated and the manufacturing cost is increased.
[0005]
The present invention has been made in view of the above problems, and can easily remove sand adhering to troughs and screws, or can provide a screw structure in which kneaded sand is less likely to adhere and kneaded sand. and to provide a method of controlling a conveyor equipment - conveying screw kneading sand that can be realized with a simple structure that conveys better flow of kneaded sand while loosening.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the control method of the kneaded sand conveying screw conveyor apparatus according to the present invention includes a step of measuring the current value of the motor during operation of the motor for rotating the screw, and during measurement. When the current value exceeds the desired reference current value, the supply of the kneading sand into the trough is stopped while the screw is still rotating, and this state is maintained for a predetermined time, and the kneading remaining in the trough A step of discharging the sand, a step of discharging the compressed sand from the blow nozzle after discharging the kneaded sand from the trough, and a point when the current value during measurement drops below the desired reference current value, A step of stopping the injection of the compressed air from the blow nozzle and restarting the supply of the kneaded sand into the trough, and monitoring the time from the stop of the supply of the kneaded sand to the restart of the supply with a timer. Stop supplying kneaded sand Supply even after more than a predetermined time, characterized in that makes a trouble display if it can not resume.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, a kneaded sand conveying screw conveyor apparatus and its control method capable of easily removing sand adhering to troughs and screws will be described as a first embodiment with reference to FIG.
In FIG. 1, a rotary shaft 5 a that is rotated by a motor 4 is disposed in a trough 3 that has an input port 1 at the top and a discharge port 2 at the bottom. A plate-like scraping plate 5b is spirally attached to the rotating shaft 5a, and a screw 6 is formed by the rotating shaft 5a and the scraping plate 5b.
[0012]
Further, a large number of blow nozzles 7 and 7 inclined in the kneading sand conveying direction are arranged at intervals on the bottom and inclined side surfaces of the trough 3, and the blow nozzles 7 and 7 are provided with compression air. -Is injected. An air pipe 8 communicates with the plurality of blow nozzles 7, 7, and an electromagnetic on-off valve 9 is attached to the base end of the air pipe 8. Further, an ammeter 11 for measuring the current value of the motor 4 is connected to the power line 10 of the motor 4, and the ammeter 11 and the electromagnetic on-off valve 9 are connected via a controller 12. They are electrically connected by a control line 12a. The current value of the motor 4 is constantly measured by the ammeter 11 when the motor 4 is in operation, and a desired reference current value is preset in the controller 12. .
[0013]
In the structure as described above, the screw 6 is first rotated by the motor 4. Then, the kneaded sand is introduced into the trough 3 from the inlet 1, transported in the direction of the outlet 2 by the scraping plate 5 b of the screw 6, and discharged from the outlet 2. If this operation is continued, the kneaded sand adheres to the trough 3 and the screw 6, and the adhesion gradually grows to lower the efficiency of conveying the kneaded sand, and the rotational resistance of the screw 6 is proportional to the adhered amount of the kneaded sand. Increase.
[0014]
At this time, as the rotational resistance of the screw 6 increases, the current value of the motor 4, which is constantly measured by the ammeter 11, increases, but a desired reference current preset in the controller 12. When the value is exceeded, the supply of the kneaded sand into the trough 3 is stopped while the screw 6 is rotated. Then, when a predetermined time elapses in this state, the kneaded sand remaining in the trough 3 is discharged. The predetermined time at this time is set in advance by a timer (not shown).
[0015]
When the timer expires, the electromagnetic on-off valve 9 is opened, the compressed air is sprayed from the blow nozzles 7 and 7, and the kneaded sand adhering to the trough 3 and screw 6 is peeled and removed by the air blower. Then, the removed adhered sand is conveyed toward the discharge port 2 and discharged. During this time, when the current value of the motor 4 being measured by the ammeter 11 falls below a desired reference current value preset in the controller 12, the electromagnetic on-off valve 9 is closed and adhered by an air blower. The sand removal operation is stopped and the supply of the kneaded sand into the trough 3 is resumed.
[0016]
In addition, the time from the supply stop of the kneaded sand to the restart of the supply is monitored by a timer or the like, and if the supply cannot be resumed even after a predetermined time has elapsed after the supply of the kneaded sand is stopped, an abnormality is displayed. Good.
[0017]
Next, a second kneaded sand conveying screw conveyor apparatus that can realize a screw structure in which the kneaded sand is less likely to adhere and a kneaded sand that is conveyed and loosened to improve the flow of the kneaded sand with a simple structure. An embodiment will be described with reference to FIG.
In FIG. 2, a rotating shaft 16a that is rotated by a motor (not shown) is disposed in a trough 15 that has an input port 13 at the top and a discharge port 14 at the bottom.
[0018]
A large number of round bars 16b and 16b as support members are spirally arranged on the rotary shaft 16a at intervals, and a plate-shaped scraping plate 16c is disposed on the large number of round bars 16b and 16b. The space 17 is formed between the bottom of the scraping plate 16c and the rotary shaft 16a. Further, a large number of round bars 16d and 16d as stirring members are arranged at intervals in front and rear positions of the spiral scraping plate 16c on the rotary shaft 16a, and the round bars 16d and 16d and the rotary shaft are arranged. A screw 18 is formed by 16a, round bars 16b, 16b and scraping plate 16c.
[0019]
In the structure as described above, the screw 18 is first rotated by a motor (not shown). Then, the kneaded sand is introduced into the trough 15 from the inlet 13, transported in the direction of the outlet 14 by the scraping plate 16 c of the screw 18, and discharged from the outlet 14.
[0020]
At this time, the scraping plate 16c is spirally attached to the large number of round bars 16b and 16b in a state of being lifted from the rotating shaft 16a. By forming 17 and 17, the kneaded sand is less likely to adhere to the screw 18. Further, a large number of round bars 16d, 16d are arranged at intervals in the front and rear positions of the spiral scraping plate 16c on the rotary shaft 16a, so that a part of the kneaded sand is condensed into a lump of sand. Even if it is supplied, the lump of sand is crushed and stirred by the large number of round bars 16d, 16d, so that the flow of the kneaded sand can be improved.
[0021]
In the embodiment of the present invention, the first example and the second example have been described, but the screw 18 of the second example is applied to the first example instead of the screw 6 of the first example. If this is done, the sand adhering to the trough and screw can be easily removed, and the kneaded sand can be prevented from adhering to the screw structure, and the kneaded sand is conveyed while being loosened to improve the flow of the kneaded sand. Can be realized with a simple structure.
[0022]
【The invention's effect】
As is apparent from the above description, the present invention has a step of measuring the motor current value during operation of the motor for rotating the screw, and the current value during measurement exceeds a desired reference current value. In this case, the step of stopping the supply of the kneaded sand into the trough while the screw is rotating, maintaining this state for a predetermined time, and discharging the kneaded sand remaining in the trough; After discharging the air, the process of injecting the compression air from the blow nozzle, and the injection of the compression air from the blow nozzle is stopped when the current value during measurement drops below the desired reference current value. And a step of restarting the supply of the kneaded sand into the trough, and monitoring the time from the supply stop of the kneaded sand to the restart of the supply with a timer, If the supply cannot be resumed after a lapse It is so arranged to the fault display, trough and screw - is equal various effects is Ru can be easily remove adhering sand to.
[Brief description of the drawings]
FIG. 1A is a longitudinal sectional front view showing a first embodiment of the present invention.
(B): It is an AA arrow view in (A).
FIG. 2A is a longitudinal sectional front view showing a second embodiment of the present invention.
(B): It is an AA arrow view in (A).
(C): It is a partially cutaway enlarged view of (A).
[Explanation of symbols]
1 13 Input port 2 14 Discharge port 3 15 Trough 4 Motor 5a 16a Rotating shaft 5b 16c Scraping plate 6 18 Screw
7 Blow nozzle 9 Electromagnetic switching valve 11 Ammeter 12 Controller 16b Support member 16d Stirring member 17 Space

Claims (1)

When the motor that rotates the screw is operating, the process of measuring the current value of the motor, and when the current value during measurement exceeds the desired reference current value, the screw remains rotated The supply of the kneaded sand into the trough is stopped, this state is maintained for a predetermined time, the kneaded sand remaining in the trough is discharged, and after the kneaded sand is discharged from the trough, the compression air is discharged from the blow nozzle. And when the current value being measured falls below the desired reference current value, the injection of the compressed air from the blow nozzle is stopped and the supply of the kneaded sand into the trough is resumed. It possesses a step of, wherein the time from the supply stop of the kneaded sand to supply restart timer - abnormality display when monitored by, even after more than a predetermined time after stop of the supply of kneading the sand supply can not be restarted kneading, characterized in that makes the The method of the conveyor device - screw conveyor of.

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