JPH0346337Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that issues an alarm when the amount of coating agent supplied from a coating agent supply source to a coating machine deviates from a predetermined supply amount.

For example, a hydraulic atomization type (airless) applicator is normally used when applying mold coating agents and mold release agents such as graphite powder slurry liquid to castings and molds; Since the nozzle hole is extremely small, the nozzle hole is easily clogged by coarse particles contained in the coating agent. In addition, even if the nozzle hole expands due to wear and the discharge amount of the coating agent changes, adjusting the discharge amount by adjusting the fluid pressure of the coating agent will affect the finished state of the coated item. This is not preferable because it adversely affects the atomization state of the coating agent, which is closely related. Therefore, if the amount of coating material discharged changes due to clogging of the nozzle hole or enlargement of the nozzle hole, it is necessary to clean the nozzle hole or replace the nozzle body. Therefore, in order to obtain high-quality coated products, it is necessary to constantly monitor the discharge condition of the coating material from the hydraulic atomization type coating machine, that is, the coating condition, but the environment for coating operations is generally very poor. In many cases, the entire application process is automated due to extremely high temperatures and high concentrations of hazardous substances, making it difficult for people to constantly monitor the application status of the applicator, and In many cases, it is not possible to detect changes in the coating condition of the coating machine just by looking at it, so abnormalities in the coating condition are not noticed until coating defects such as uneven coating or sagging occur on the object to be coated. This is the actual situation.

The present invention was developed in view of the above-mentioned circumstances, and the purpose of the present invention is to improve the steady discharge amount of the coating agent from the coating machine, that is, the constant discharge amount of the coating agent supplied from the coating agent supply source to the coating machine. The supply amount is constantly monitored, and when the steady supply amount deviates from the predetermined supply amount, an alarm is immediately issued, and an abnormality in the coating state of the coating machine is detected before a coating defect occurs on the coated article. The objective is to provide a device that can detect

Another purpose of the present invention is to detect the flow rate of the coating agent without contacting it and to control the supply (discharge) of the coating agent.
To provide a device capable of monitoring the steady supply amount of a coating agent without causing malfunction even when ON-OFF control is performed, and promptly generating an alarm when the steady supply amount deviates from a predetermined value range. There is a particular thing.

However, according to the present invention, in a coating device in which the control valve is opened and closed to supply and stop supplying the coating agent to the coating machine based on a signal from the coating agent ON-OFF control section, the coating agent is connected from the coating agent supply source to the coating machine. A flow rate detection section using ultrasonic waves that detects the flow rate of the supplied coating material and outputs a signal according to the flow rate, and a signal level from the flow rate detection section that does not reach a predetermined permissible signal level. an alarm signal output section that outputs an alarm signal when the alarm signal is exceeded, an alarm device that issues an alarm according to the signal from the alarm signal output section, and interposed between the alarm device and the alarm output section, A switching mechanism that opens a circuit between the alarm signal output section and the alarm in synchronization with the control valve when the supply of coating material to the coating machine is stopped, and a switching mechanism that opens a circuit between the alarm signal output section and the alarm when the supply of coating material to the coating machine is stopped, and a switching mechanism that is delayed only at the start when supplying the coating material to the coating machine is started. There is provided a flow rate abnormality alarm device comprising: a delay operation section that closes the circuit of the switching mechanism.

In other words, the flow rate abnormality alarm device according to the present invention is as follows:
The steady flow rate of the coating material supplied to the coating machine is constantly monitored, and if the steady flow rate deviates from a predetermined flow range, a warning can be immediately issued, thereby preventing coating defects on the coated article. It is possible to detect an abnormality in the coating state of the coating machine before it occurs.

In addition, since the flow rate of the coating agent is detected non-contact using ultrasonic waves, there is no obstruction to the flow of the coating agent or cause of clogging, and the detection area is not attacked by the coating agent. do not have.

Furthermore, during coating work, ON-OFF control of coating material supply (discharge) is normally performed, and the flow rate of coating material flowing into the coating machine fluctuates in a pulsed or pulsating manner, and the flow rate detection signal also fluctuates accordingly.
In the device of this invention, the coating agent supply is ON-
The switching mechanism operated by the OFF control signal eliminates the influence of pulsed or pulsating signals that interfere with steady flow rate detection, so ON-OFF control of coating agent supply is performed. It is possible to monitor the steady supply flow rate of the coating agent without causing any malfunction even when the steady supply flow rate deviates from a predetermined value range, and to immediately issue an alarm.

The flow rate detection unit used in this invention may be one in which the detection unit body and the detector (sensor) are integrated, but in practice, flow rate detection is often performed at multiple locations, so a single unit may be used. It is more economical and desirable to have a configuration in which a plurality of detectors (sensors) can be connected separately to the main body of the detection unit via a distributor.

Further, the predetermined permissible level of the flow rate detection signal may be a preset fixed level, but in practice it can be varied stepwise or steplessly so that any permissible level can be easily set at any time. It is desirable that

The present invention will be explained in detail below based on one embodiment.

FIG. 1 is a flowchart showing an example of a case where the device of the present invention is applied to a hydraulic atomization electrostatic coating machine for graphite powder slurry liquid. The liquid 2 is supplied by a coating agent supply pump 3 to a hydraulic atomizing electrostatic applicator 5 via coating agent supply paths 4a and 4b. A control valve 6 is connected in the middle of the coating agent supply paths 4a and 4b, and controls ON/OFF the supply of the graphite powder slurry liquid 2 supplied from the coating agent supply pump 3 to the electrostatic coating machine 5. . Further, a coating agent circulation path 7 is provided in the coating agent supply paths 4a, 4b and the control valve 6.
are in communication with each other to prevent graphite powder from settling and accumulating in the coating agent supply path 4a and the coating agent circulation path 7.
The graphite powder slurry liquid 2 is constantly circulated. A back pressure valve 8 is connected in the middle of the coating agent circulation path 7, so that when the control valve 6 is turned on and off, the load applied to the coating agent supply pump 3 does not fluctuate so much. The pressure in channel 4a is adjusted so that it does not increase or decrease appreciably. Since there is a risk that high voltage may be leaked and applied to the control valve 6 from the electrostatic applicator 5 through the coating agent supply path 4b, the control valve 6 is supplied with the coating agent by compressed air from the compressed air supply source 9. ON-OFF control section 10
It is operated in an electrically insulating manner via the solenoid valve 11 by an electric signal from the solenoid valve 11. In some cases, the coating agent tank 1, coating agent supply pump 3, coating agent supply path 4a, coating agent circulation path 7, etc. are also provided with electrical insulation measures. It goes without saying that if there is no risk of high voltage being applied to the control valve 6, the control valve 6 may be operated directly electrically.

As shown in FIG. 2, an ultrasonic transmitter 12 and an ultrasonic receiver 12' are built into the coating agent supply path 4b to detect the flow rate of the graphite powder slurry liquid 2 flowing therethrough. A detector (sensor) 13 is attached to the outside of the coating material supply pipe (in this embodiment, an electrically insulating pipe such as a polyethylene pipe) 4'b, and transmits the transmitted wave 14 from the ultrasonic transmitter 12. is emitted and its reflected wave 14' is received by a receiver 12'. Then, the detection unit main body 15 connected to the detector (sensor) 13 accurately measures the frequency difference between the transmitted wave 14 and the reflected wave 14', and utilizes the Doppler effect to
The flow rate of the graphite powder slurry liquid 2 flowing through b is accurately detected, and an electric signal corresponding to the flow rate is output.
The detector (sensor) 13 and the detector main body 15 constitute a flow rate detection section. 1 detection unit body 1
5, when detecting the flow rate of the coating agent flowing into multiple coating agent supply paths, the detection unit main body 15 and the detector 1
It is possible to connect a distributor (not shown) between the detector 3 and the detector 3, and to connect a plurality of detectors 13 via the distributor to sequentially perform detection. In addition to the method using the above-mentioned Doppler effect as a flow rate detection method using ultrasonic waves, there are also methods that measure the propagation angle of ultrasonic waves, and in the case of the present invention, any of these methods can be adopted. You may.

The flow rate detection signal outputted from the flow rate detection unit body 15 is checked in the alarm signal output unit 16 to see if it is within a predetermined permissible signal level, and the flow rate detection signal level is determined to be within a predetermined permissible signal level. When it does not reach or exceeds
An alarm signal is output from the alarm signal output section 16.
The permissible level of the signal can be varied stepwise or steplessly, so that a predetermined supply amount of the graphite powder slurry liquid 2 to the electrostatic coating machine 5 can be arbitrarily set at any time. Although the predetermined supply amount of the graphite powder slurry liquid 2 can be set by changing the permissible level of the signal itself as described above, it is possible to set the predetermined supply amount of the graphite powder slurry liquid 2 by changing the permissible level of the signal itself.
This can also be done by making the amplification or attenuation rate of the flow rate detection signal variable.

The signal output from the alarm signal output section 16 is transmitted to the alarm device 18 via the switching mechanism 17, and the alarm device 18 issues a light and/or sound alarm.

In addition, during the coating work, ON-OFF control of the coating agent supply (discharge) is performed by discharging or stopping the coating agent from the applicator 5 according to the shape of the article to be coated, the purpose of coating, etc. In this example, the coating agent is
By operating the control valve 6 in response to a signal from the -OFF control section 10 and controlling the supply of the coating agent, ON-OFF control of coating agent discharge is performed.
Therefore, the flow of the coating agent (graphite powder slurry liquid 2) flowing through the coating agent supply path 4b fluctuates in a pulsed or pulsating manner, and accordingly, the flow rate detection signal from the detection unit main body 15 that detects the flow also changes. It fluctuates as well. Since it would be inconvenient for the alarm 18 to operate each time due to signal fluctuations that are essentially unrelated to substantial flow rate changes, in the present invention, as shown in this embodiment, the alarm signal output section 16
The influence of the signal fluctuation is removed by a switching mechanism 17 that is interposed between the controller and the alarm 18 and operates synchronously with the solenoid valve 11 in response to the OFF control signal of the coating material supply (discharge). ing. That is, when a signal to stop the coating agent supply is transmitted from the coating agent ON-OFF control section 10 to the solenoid valve 11, the signal is simultaneously transmitted to the switching mechanism 17, and the switching mechanism 17 outputs the alarm signal output section 1.
6 and the alarm device 18, the signal from the alarm signal output section 16 is not transmitted to the alarm device 18. Therefore, the supply of the coating agent is stopped and the flow rate detection signal indicates that the flow rate flowing through the coating agent supply path 4b is 0, and the alarm signal output section 16 outputs a subsequent alarm signal indicating that the coating condition is abnormal. However, since the signal is not transmitted to the alarm device 18, the alarm device 18 will not operate. Next, the coating agent
When a signal to start supplying the coating agent is issued from the ON-OFF control unit 10, the signal is transmitted to the solenoid valve 11, and at the same time, it is transmitted to the switching mechanism 17 after a certain period of time via the delay circuit unit 19 as a delay operation unit. transmitted to. That is, it takes a certain amount of time (time lag) after the electromagnetic valve 11 operates to operate the control valve 6 and the supply of the coating agent is started until the coating agent starts to steadily flow inside the coating agent supply path 4b. Therefore, the delay circuit section 19 interposed between the coating agent ON-OFF control section 10 and the switching mechanism 17 allows the switching mechanism 17 to be turned on only when the coating agent supply starts.
The switching mechanism 17 is operated to close the circuit between the alarm signal output 16 and the alarm 18 after the coating agent starts flowing steadily in the coating agent supply path 4b. ing.
Therefore, the alarm 18 will not malfunction even due to fluctuations in the flow rate detection signal at the start of coating agent supply.
As described above, the delay circuit section 19 transmits the coating agent supply stop signal to the switching mechanism 17 immediately, and transmits the coating agent supply start signal to the switching mechanism 17 after a certain elapsed time. Operate. As the switching mechanism 17, a semiconductor such as an SCR is preferably used in addition to a normal electromagnetic relay. Note that when a delay relay is used as the switching mechanism 17, the delay circuit section 19 is not necessary. Furthermore, in this embodiment, ON-OFF control of the coating agent supply (discharge) was performed by the control valve 6, but a needle valve is built into the applicator 5, and the coating agent is supplied by opening and closing the needle valve. (Discharge) ON
-OFF control may be performed.

Using the apparatus described above, experiments were conducted by setting a predetermined supply amount of coating agent each time for various coating agents such as graphite powder slurry liquid, organic solvent paint, water-based paint, and metallic paint. When I got used to it, I was able to monitor the steady supply amount of the coating material without causing any malfunction even when ON-OFF control of the coating material supply (discharge) was performed, and when the steady supply amount was outside the permissible range of the prescribed supply amount. In some cases, the alarm could be issued quickly. In addition, by providing a switching mechanism that operates in synchronization with the control valve, and by using a delay operation part to delay the operation of the switching mechanism only when the supply of coating material starts, it is possible to prevent the flow rate from decreasing temporarily during supply. It was extremely effective in preventing false alarms and in cases where ON-OFF control of the coating machine was frequently repeated. For example, when a coating machine is installed on a robot installed on a conveyor or the like and coats moving parts by repeating automatic ON-OFF control frequently, the functionality of this flow rate abnormality alarm device is important. was very effective.

The device of this invention can be applied to various electrostatic and non-electrostatic coating devices such as hydraulic atomization, air atomization, centrifugal atomization, and electrostatic atomization, as well as oil application devices and humidification devices. Furthermore, it can be applied to various supply devices for surface treatment liquids, various chemical solutions, suspensions of graphite powder, etc., inks, dyes, and the like.

[Brief explanation of drawings]

Figure 1 is a flowchart (system diagram) showing an example of the case where the device of the present invention is applied to a hydraulic atomization type electrostatic coating machine for graphite powder slurry liquid, and Figure 2 shows the detector (sensor) of the present invention. ) is a partial cross-sectional view of a coating agent supply path with a coating agent tank, 4a and 4b a coating agent supply path, 5 a hydraulic atomizing electrostatic applicator, 6 a control valve, 1
2 is an ultrasonic transmitter, 12' is an ultrasonic receiver, 13
is the detector (sensor), 15 is the detection unit body, 16
is an alarm signal output section, 17 is a switching mechanism, 1
8 indicates each alarm.

Claims (1)

[Scope of utility model registration request] In a coating device that opens and closes a control valve to supply and stop supplying coating agent to the applicator based on signals from the coating agent ON-OFF control section, the flow rate of the coating agent supplied from the coating agent supply source to the applicator is controlled. detect,
A flow rate detection section using ultrasonic waves that outputs a signal according to the flow rate, and an alarm that outputs an alarm signal when the signal level from the flow rate detection section does not reach or exceeds a predetermined permissible signal level. a signal output section; an alarm device that issues an alarm in response to a signal from the alarm signal output section; and an alarm device that is interposed between the alarm device and the alarm signal output section, and that A switching mechanism that opens a circuit between the alarm signal output section and the alarm in synchronization with a control valve, and an operation that closes the circuit of the switching mechanism with a delay only at the start of supply of coating agent to the coating machine. 1. A flow rate abnormality alarm device comprising: a delay operation section for causing