JP3133320U - Powder coating equipment - Google Patents

Abstract

Disclosed is a powder coating apparatus capable of performing coating by controlling the discharge amount of a powder paint with excellent responsiveness.
A discharge amount control panel 11 is fixed to an outer surface of a paint tank 1 to which an injector 2 and a powder flow rate measuring device 7 are attached, and the discharge amount control panel 11 and the injector 2 are mutually connected via an air tube 12. The powder flow rate measuring device 7 is connected to the discharge amount control panel 11 via the signal cable 13 while being connected. A gun voltage control panel 15 is fixed to a gun support 14 that supports the powder coating gun 6, and the gun voltage control panel 15 and the powder coating gun 6 are connected via a gun cable 16 and the powder coating gun 6. The injector 2 is connected via a paint hose 5. A main control panel 17 is installed apart from the tank 1 and the gun support 14 and is electrically connected to the discharge amount control panel 11 and the gun voltage control panel 15 via communication cables 18 and 19, respectively.
[Selection] Figure 1

Description

  The present invention relates to a powder coating apparatus, and more particularly to a technique for improving control response of a discharge amount of a powder paint.

  In the powder coating operation, it is always necessary to supply a certain amount of the powder coating material to the coating gun for homogenization of the finished coating film and effective use of the powder coating material. A conventional powder coating apparatus of this type is shown in FIG. The injector 2 is attached to the tank 1 containing the powder coating material, and suction air is blown from the controller 3 to the nozzle of the injector 2 through the air tube 4, whereby the powder coating material in the tank 1 is sucked and the coating hose 5 is connected. To the powder coating gun 6. A powder flow rate measuring device 7 for measuring the flow rate of the powder paint is attached to the injector 2, and the actual flow rate of the powder paint measured by the powder flow rate measuring device 7 and the discharge amount set value input from the controller 3. The pressure of the suction air blown into the nozzle of the injector 2 is controlled so that the actual flow rate becomes equal to the discharge amount set value. Then, a gun voltage is applied from the controller 3 to the powder coating gun 6 via the gun cable 8, and the powder coating material is discharged from the powder coating gun 6 toward the object to be coated.

  In general, the powder coating gun 6 and the tank 1 are arranged in a painting environment such as a painting booth, while the controller 3 operated by an operator needs to be installed in a clean environment. The painting gun 6 and the tank 1 are arranged apart from each other. For this reason, the air tube 4 that connects the controller 3 and the injector 2 and the gun cable 8 that connects the controller 3 and the powder coating gun 6 usually have a length of about 10 to 20 m.

  However, the longer the air tube 4 is, the more time is required for the air pressure supplied from the controller 3 to reach the injector 2, and the start of the discharge of the powder paint from the powder coating gun 6 is delayed. In particular, in a coating method in which the presence or absence of an object to be coated conveyed by a conveyor or the like is detected by a photoelectric sensor or the like and the discharge of the powder coating from the powder coating gun 6 is automatically turned on / off, the air tube 4 The discharge start timing is deviated due to the length.

  Further, when changing the discharge amount setting value by changing the discharge amount setting value, the longer the air tube 4 is, the longer time it takes for the actual flow rate of the powder paint to reach the discharge amount setting value. Become. For example, as shown in FIG. 5, when the discharge rate is changed from 100 g / sec to 150 g / sec, when the length L = 2 m of the air tube 4, the actual flow rate of the powder paint is discharged in 1.2 sec. While the amount set value was reached, it took 2.6 seconds for the length L = 10 m of the air tube 4 and 3.7 seconds for the length L = 20 m.

  So, before the object reached the coating position, it started to discharge the powder paint as soon as possible, or when the discharge amount setting value was changed, it was thrown away for a few seconds and then applied to the object. In this case, there is a problem that a large amount of the powder coating material that has been ejected but does not adhere to the object to be coated is wasted. Although the powder coating material that does not adhere to the object can be collected and reused, it is difficult to recover 100%, and generation of useless powder coating material has been forced.

  Furthermore, since a pressure loss proportional to the length of the air tube 4 occurs, the longer the air tube 4 is, the lower the maximum discharge amount that can be discharged, and there is a possibility that a necessary discharge amount cannot be obtained depending on the conditions. When a plurality of tanks 1 and powder coating guns 6 are arranged, the lengths of the air tubes 4 are different even if the controller 3 supplies the same air pressure to the injectors 2 of the plurality of tanks 1. And a difference arises in the pressure before the injector 2, and as a result, a discharge amount will also differ.

  The present invention has been made to solve such problems, and an object thereof is to provide a powder coating apparatus capable of performing coating by controlling the discharge amount of the powder paint with excellent responsiveness. To do.

  A powder coating apparatus according to the present invention includes a tank for storing a powder coating, an injector connected to the tank, a powder coating gun connected to the injector, and a flow rate of the powder coating sucked by the injector. Measured with a powder flow rate measuring device and a powder flow rate measuring device which is disposed in the vicinity of the tank and sucks air into the injector and sucks the powder paint from the tank and supplies it to the powder coating gun. A discharge amount control panel that feedback controls the suction air pressure so that the flow rate of the powder coating becomes the discharge amount set value, and a gun voltage that is disposed in the vicinity of the powder coating gun and that is applied to the powder coating gun. The gun voltage control panel, the discharge amount control panel, and the gun voltage control panel are electrically connected to each other via a communication cable, and the discharge amount set value is output to the discharge amount control panel. It is obtained by a main control board for driving and controlling the discharge amount control panel and cancer voltage control board outputs a cancer voltage setting value to the voltage control board.

The injector has a main nozzle and a sub nozzle, the main control panel outputs the carrier air flow rate setting value to the discharge amount control panel, and the discharge amount control panel blows suction air into the main nozzle of the injector and dilutes air into the sub nozzle. The pressure of the suction air and the pressure of the dilution air can be adjusted such that the sum of the flow rate of the suction air and the flow rate of the dilution air becomes the carrier air flow rate set value. Preferably, the discharge amount control panel performs PID control on the pressure of the suction air and the pressure of the dilution air.
A reciprocator that moves the powder coating gun while holding it may also be provided.

  According to this device, the discharge amount control panel is disposed in the vicinity of the tank and the gun voltage control panel is disposed in the vicinity of the powder coating gun, and the discharge amount control panel and the gun voltage control panel are respectively connected via the communication cables. Since the main control panel is electrically connected, the discharge control panel and tank injector can be connected with a short air tube while the main control panel is placed away from the tank and powder coating gun. Thus, it is possible to perform coating by discharging a powder coating with a large discharge amount with excellent responsiveness.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1
FIG. 1 shows the configuration of a powder coating apparatus according to Embodiment 1 of the present invention.
An injector 2 and a powder flow rate measuring device 7 are attached to a tank 1 that contains a powder coating material. Further, a discharge amount control panel 11 is fixed to the outer surface of the tank 1, and the discharge amount control panel 11 and the injector 2 are connected to each other via an air tube 12, and the powder flow rate measuring device 7 receives a signal. The discharge amount control panel 11 is connected via a cable 13.

A powder coating gun 6 is supported on a gun support 14, and an injector 2 is connected to the powder coating gun 6 via a paint hose 5. A gun voltage control board 15 is fixed to the gun support base 14, and the gun voltage control board 15 and the powder coating gun 6 are connected via a gun cable 16.
The tank 1 and the gun support 14 are arranged in a painting environment such as a painting booth (not shown), and the main control panel 17 is installed in a clean environment away from the painting environment. The main control panel 17, the discharge amount control panel 11, and the gun voltage control panel 15 are electrically connected via communication cables 18 and 19, respectively.

The discharge amount control panel 11 is connected to a compressed air source (not shown). By blowing suction air into the injector 2, the powder paint is sucked from the tank 1 and supplied to the powder coating gun 6 and the powder flow rate is measured. The suction air pressure is feedback-controlled so that the flow rate of the powder coating material measured by the apparatus 7 becomes the discharge amount set value.
The gun voltage control panel 15 applies a gun voltage to the powder coating gun 6 via the gun cable 16.

  The main control panel 17 drives and controls the discharge amount control panel 11 and the gun voltage control panel 15. The main control panel 17 outputs a discharge amount setting value and a carrier air flow rate setting value to the discharge amount control panel 11, and The gun voltage set value and the gun current set value are output to drive and control the discharge amount control panel and the gun voltage control panel. Further, the main control panel 17 displays input conditions for inputting painting conditions including these various set values, driving / stopping instructions, etc., and the operating status and painting conditions of the entire powder coating apparatus. For example, the input unit and the display unit can be configured from a combination of a display and a keyboard or a touch panel type liquid crystal screen.

  Here, the configuration of the tank 1, the injector 2, the powder flow rate measuring device 7 and the discharge amount control panel 11 is schematically shown in FIG. The tank 1 for storing the powder coating material F is a so-called fluidized bed tank provided with a porous plate 21, and fluidized air is blown into the powder coating material F so that the powder coating material F is kept in a fluid state in the tank 1. One end of the transfer pipe 22 is inserted into the tank 1, and the injector 2 is connected to the other end of the transfer pipe 22. A powder flow rate measuring device 7 is disposed between the tank 1 and the injector 2. The powder flow rate measuring device 7 measures the flow rate of the powder coating F based on the density in the transfer tube 22 measured as a change in capacitance and the flow rate Qf of measurement air introduced into the transfer tube 22. And a plurality of conductor plates 23 wound around the outer periphery of the conveyance tube 22, an amplifier circuit 24 connected to these conductor plates 23, and a correction circuit 25 connected to the amplifier circuit 23. . An output signal from the correction circuit 25 is input to the discharge amount control panel 11 via the signal cable 13, and suction air and dilution air are supplied from the discharge amount control panel 11 to the main nozzle 2a and the sub nozzle 2b of the injector 2, respectively. The

  The discharge amount control panel 11 is connected to a compressed air source (not shown) and opened / closed based on an operation signal of the powder coating gun 6, and suction connected to the valve 26 via a branch point A, respectively. An air pressure regulator 27 and a dilution air pressure regulator 28 are provided. These regulators 27 and 28 are connected to the main nozzle 2 a and the sub nozzle 2 b of the injector 2 through the corresponding air tubes 12. Further, the discharge amount control panel 11 has a control circuit 29 connected to the regulators 27 and 28 and the correction circuit 25 of the powder flow rate measuring device 7. The main control panel 17 is electrically connected to the control circuit 29 via the communication cable 18.

Next, the operation of this powder coating apparatus will be described. First, the discharge amount setting value Qm of the powder coating material F from the main control panel 17 by the operator, the transfer air flow rate setting value Qt for transferring the powder coating material F to the powder coating gun 6, the gun voltage setting value, and the gun current Setting values are input, and these setting values are stored in a memory (not shown) built in the main control panel 17. Further, when an operation signal for instructing the start of operation of the powder coating apparatus is input from the main control panel 17 by the operator, the main control panel 17 sets the discharge amount stored in the memory via the communication cable 18. The value Qm, the conveyance air flow rate setting value Qt, and the operation signal are transmitted to the discharge amount control panel 11, and the gun voltage setting value, the gun current setting value, and the operation signal stored in the memory are transmitted via the communication cable 19. Is transmitted to the gun voltage control panel 15.
It is assumed that fluid air is previously blown into the tank 1 and the powder coating material F is kept in a fluid state in the tank 1.

The powder coating gun 6 is driven with the set gun voltage and gun current by the gun voltage control panel 15 which has received the gun voltage set value, gun current set value and operation signal from the main control panel 17.
On the other hand, the valve 26 is opened by the control circuit 29 of the discharge amount control panel 11 that has received the operation signal from the main control panel 17, and compressed air from a compressed air source (not shown) passes through the valve 26, and then at a branch point A. The divided air is blown into the main nozzle 2a of the injector 2 through the suction air pressure regulator 27, and the dilution air is blown into the sub nozzle 2b of the injector 2 through the dilution air pressure regulator 28. The powder paint F is sucked into the transport pipe 22 from the tank 1 by the suction air blown into the main nozzle 2a, and further the powder paint F is passed through the paint hose 5 by the suction air and dilution air. 6 and ejected from the powder coating gun 6 toward the object to be coated.

  When the powder coating is started in this way, the flow rate of the powder coating material F flowing through the transport pipe 22 is detected as a change in capacitance by the plurality of conductor plates 23 of the powder flow rate measuring device 7, and the amplification circuit After the detection signal amplified in 24 is subjected to, for example, zero point correction in the correction circuit 25, it is input to the control circuit 29 of the discharge amount control panel 11 as a signal representing the supply amount Qp of the powder coating material F. Here, the zero point correction is to reduce the influence of the powder adhering to the inner wall of the conveying pipe 22 during the supply of the powder coating F to a level that does not cause a practical problem. The measured value during operation is corrected using the measured value (measured value corresponding to the amount of adhered powder) as a correction reference value.

  The control circuit 29 that has input a signal representing the supply amount Qp from the correction circuit 25 compares the supply amount Qp represented by this signal with the discharge amount setting value Qm of the powder paint F input from the main control panel 17. The suction air pressure regulator 27 is adjusted according to the excess / deficiency with respect to the discharge amount setting value Qm, and the suction air pressure Pfm blown into the main nozzle 2a of the injector 2 is feedback-controlled. Thus, the powder coating gun 6 is always supplied with the powder coating F having the discharge amount set value Qm. At the same time, the control circuit 29 calculates the difference Qt−Qfm between the carrier air flow rate setting value Qt input from the main control panel 17 and the suction air flow rate Qfm, and the dilution air flow rate Qfs matches this difference. The pressure regulator 28 for dilution air is adjusted as follows. That is, the dilution air is controlled so that the flow rate Qt of the carrier air, which is the sum of the flow rate Qfm of suction air and the flow rate Qfs of dilution air, is constant.

  In this way, the fluctuation of the suction air flow rate Qfm accompanying the control of the powder coating material discharge amount from the powder coating gun 6 can be compensated by the dilution air flow rate Qfs, and the conveyance air flow rate Qt can be kept constant. It is possible to form a coating film having a stable film thickness distribution.

As described above, the discharge amount control panel 11 is fixed to the outer surface of the tank 1, and the main control panel 17 drives and controls the discharge amount control panel 11 via the communication cable 18. The injector 2 can be connected with a short air tube 12. Accordingly, it is possible to perform coating while suppressing a decrease in responsiveness and an increase in pressure loss due to the length of the air tube, and controlling the discharge amount of the powder paint with excellent responsiveness.
In addition, the gun voltage control panel 15 is fixed to the gun support 14 that supports the powder coating gun 6, and the gun voltage control panel 15 is driven and controlled by the main control panel 17 via the communication cable 19. The gun cable 16 that connects 15 and the powder coating gun 6 can be shortened.

Note that the measurement air introduced into the conveyance pipe 22 in the powder flow rate measuring device 7 is also a part of the conveyance air for conveying the powder coating material F to the powder coating gun 6. Since Qf is extremely smaller than the flow rate Qfm of suction air and the flow rate Qfs of dilution air, it does not have to be included in the flow rate Qt of transport air. However, the sum of the flow rate Qf of suction air, the flow rate Qfs of dilution air, and the flow rate Qf of measurement air may be taken as the flow rate Qt of transport air, taking into account the flow rate Qf of measurement air.
Furthermore, the pressure regulators are used as means for adjusting the flow rates of the suction air and the dilution air, respectively. However, the present invention is not limited to this, and for example, a control valve may be used.

  Further, the discharge amount control panel 11 is fixed to the outer surface of the tank 1, but the present invention is not limited to this, and the discharge amount control panel 11 and the injector 2 are arranged by arranging the discharge amount control panel 11 in the vicinity of the tank 1. It is only necessary that the length of the air tube 12 to be connected can be set short.

Embodiment 2
FIG. 3 shows the configuration of a powder coating apparatus according to Embodiment 2 of the present invention. In the second embodiment, in the apparatus of the first embodiment shown in FIG. 1, the powder coating gun 6 is held by the reciprocator 30 instead of the gun support 14 and the powder coating gun 6 is moved. It is configured to perform powder coating.
In general, when the powder coating gun 6 is moved up and down using such a reciprocator 30, the discharge amount of the powder paint from the powder coating gun 6 may fluctuate, but the discharge amount control panel 11 and the injector 2 is connected by a short air tube 12, the control response of the discharge amount is improved, and a stable discharge amount can be ensured.

  In the first and second embodiments, the actual supply is based on the difference between the actual supply amount Qp of the powder paint measured by the powder flow rate measuring device 7 and the discharge amount setting value Qm input from the main control panel 17. The pressure Pfm of the suction air blown into the main nozzle 2a of the injector 2 can also be PID controlled so that the amount Qp becomes equal to the discharge amount set value Qm. The PID control is a control system that combines a proportional operation that performs smooth control without hunting, an integration operation that automatically corrects an offset, and a differential operation that accelerates the response to a disturbance. By adopting such a control method, it becomes possible to smoothly control the discharge amount of the powder paint with excellent responsiveness.

  In the first and second embodiments, powder coating is performed using only one powder coating gun 6, but a plurality of powder coating guns 6 are driven by a common main control panel 17. It can also be configured. A plurality of tanks 1 and a plurality of injectors 2 are arranged corresponding to a plurality of powder coating guns 6, respectively, and a plurality of gun voltage control panels 15 corresponding to the vicinity of the plurality of powder coating guns 6 are arranged. A plurality of discharge amount control panels 11 corresponding to the vicinity of the tank 1 are arranged, and the plurality of discharge amount control panels 11 and the plurality of gun voltage control panels 15 are connected to each other by a communication cable. The drive control may be performed with In each tank 1, the length of the air tube 12 connecting the injector 2 and the discharge amount control panel 11 can be set short, and the discharge amount in each powder coating gun 6 can be controlled with excellent responsiveness. Is possible.

It is a figure which shows the structure of the powder coating apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows typically the structure of a tank, an injector, a powder flow rate measuring apparatus, and a discharge amount control panel. It is a figure which shows the structure of the powder coating apparatus which concerns on Embodiment 2. FIG. It is a figure which shows the structure of the conventional powder coating apparatus. It is a graph which shows the relationship between the length of an air tube, and the control responsiveness of the discharge amount of a powder coating material.

Explanation of symbols

  1 Tank, 2 Injector, 2a Main nozzle, 2b Sub nozzle, 5 Paint hose, 6 Powder coating gun, 7 Powder flow rate measuring device, 11 Discharge control panel, 12 Air tube, 13 Signal cable, 14 Gun support base, 15 Gun voltage control panel, 16 Gun cable, 17 Main control panel, 18, 19 Communication cable, 21 Porous plate, 22 Transport pipe, 23 Conductor plate, 24 Amplifier circuit, 25 Correction circuit, 26 Valve, 27 Pressure regulator for suction air, 28 Pressure regulator for dilution air, 29 control circuit, 30 reciprocator.

Claims (4)

A tank for storing powder paint,
An injector connected to the tank;
A powder coating gun connected to the injector;
A powder flow rate measuring device for measuring the flow rate of the powder paint sucked by the injector;
The powder coating material disposed near the tank and sucking air into the injector to suck the powder coating material from the tank and supplying the powder coating gun to the powder coating gun. A discharge amount control panel for feedback controlling the pressure of the suction air so that the flow rate becomes the discharge amount set value;
A gun voltage control panel disposed in the vicinity of the powder coating gun and controlling a gun voltage applied to the powder coating gun;
The discharge amount control panel and the gun voltage control panel are electrically connected to each other via a communication cable, and output a discharge amount set value to the discharge amount control panel and output a gun voltage set value to the gun voltage control panel. And a main control panel for driving and controlling the discharge amount control panel and the gun voltage control panel. The injector has a main nozzle and a sub nozzle,
The main control panel outputs a conveyance air flow rate set value to the discharge amount control panel,
The discharge amount control panel blows suction air into the main nozzle of the injector and blows dilution air into the sub nozzle, and sucks air so that the sum of the suction air flow rate and the dilution air flow rate becomes the transport air flow rate setting value. 2. The powder coating apparatus according to claim 1, wherein the pressure of the air and the pressure of dilution air are adjusted.   The powder coating apparatus according to claim 2, wherein the discharge amount control panel performs PID control of suction air pressure and dilution air pressure.   The powder coating apparatus according to claim 1, further comprising a reciprocator that moves the powder coating gun while holding the powder coating gun.

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