JPH0644204B2 - Spray gun monitor - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to monitoring devices, and more particularly to monitoring devices used to detect fluid distributor malfunctions.

PRIOR ART Certain fluid dispensing systems include a pump having an inlet connected to a material source and an outlet connected to a distributor. For precise dispensing, the dispenser includes a valve that allows fluid to flow through an outlet such as a nozzle or fluid tip. In some systems the valves of the distributor are actuated by a controller programmed to dispense the fluid precisely or in a predetermined amount.

In many cases, it is desirable to dispense in a precise pattern or in predetermined amounts or in tandem. When operating, nozzle wear,
The precision and quantity are affected by impurities in the fluid, nozzle clogging, and factors such as pump performance.

In particular, clogging of the material flow passages in the distributor presents a major problem that adversely affects the performance of the precision dispensing system. For example, in a precision dispensing system used to coat the interior surface of the body of a multi-part can, nozzle clogging and wear can cause the body of the can to be incomplete or improperly applied.

The body of the can is applied at a rate of hundreds of minutes per minute during the manufacturing process. Therefore, an improperly functioning dispenser, or in particular, a can with a large number of improper coats, before being detected by inspection or other known means by a worn or worn nozzle. Will be manufactured. Inappropriately coated cans can adversely affect performance for storage. In some cases, the can is accelerated in degradation (ie, has a shorter life), and in other cases, such as in food and beverages, the contents are adversely affected in terms of taste and spoilage. Therefore, improper application is not desirable, and cans with such improper application cannot be used, which is costly.

Other systems, including precise deposition of thermoplastics,
Easy to get clogged. An example of such a system is described in US Pat. No. 4,166,246. These systems are used for manufacturing packaging materials such as cardboard boxes and assembling products. Clogged distribution systems can result in defective products, delaying the manufacturing process and adding unnecessary extra costs.

Known jam detection systems are inadequate and unusable for the desired accurate and rapid jam detection. For example, U.S. Pat.
072,934 discloses a method and apparatus for detecting obstructions in vapor distribution lines such as those used in liquid gasoline distributors. Such a device cannot be used for accurate coating application because it is not possible to determine nozzle conditions, i.e. clogging or wear. Hillers and others are trying to determine if there is an obstruction in the steam line by detecting the pressure on both sides of the blockage and triggering an alarm when the differential pressure exceeds a predetermined maximum value.

U.S. Pat. No. 3,816,025 describes a fluid circulation system for paint spray equipment. The secondary recirculation loop pressure sensor detects that the pressure in the secondary loop has dropped below a predetermined value in order to close the paint supply pump should the paint distribution line break.

U.S. Pat. No. 4,315,317 to Orchyard discloses a measuring, calculating and recording device for monitoring spray parameters for insecticides dispensed from an aircraft. Orchyard et al. Records pressure information, total liquid volume, liquid flow velocity, number of sprays, spraying time, and the like. The user must interpret the results of the recorded items to determine, among other things, whether a clogging condition exists. Such a delay in the determination of system conditions cannot be applied to precise coating application such as the case of the can body described above.

U.S. Pat. No. 3,482,781 includes a paint spray gun that uses air to spray paint during dispensing. A pressure gauge is attached to the gun to indicate the atomizing air pressure during dispensing operation. This device cannot accurately and reliably determine if the paint flow passage is blocked.

[Problems to be Solved by the Invention] At present, there is no system capable of quickly and automatically determining whether or not a coating spray gun is applying a coating material in a state other than a predetermined or desired state.

Accordingly, it is an object of the present invention to provide a spray gun monitoring device that can quickly and automatically determine when paint is no longer properly sprayed.

[Means for Solving the Problems] In the first and second aspects of the present invention, there is provided a spray gun for spraying paint under pressure, and a control device for giving an operation signal to the spray gun to control the opening / closing conditions thereof. In a paint system, a monitor assesses spray gun operation. The monitor has a sensor attached to the spray gun to detect the fluid pressure in the spray gun and generate a signal indicative of the fluid pressure. The comparator receives both the fluid pressure signal and the actuation signal. The pressure signal is compared to the first and second pressures. When the activation signal indicates that the spray gun is open, the monitor issues a malfunction signal if the pressure signal is not between the first and second pressures.

In an embodiment of the second aspect of the invention, the second comparator compares the fluid pressure signal with a predetermined pressure value when the spray gun is not open. If the fluid pressure signal exceeds a predetermined pressure value, a malfunction signal is emitted indicating either a defective system pump or improper system fluid pressure.

[Embodiment] FIG. 1 shows a distribution (paint) of an embodiment according to the first invention, which comprises a main distributor (spray gun) 20, a distributor (spray gun) control device 22, and a fluid (paint) source 30. The system is shown. The decomposer controller 22 provides an actuation signal via a conductor 23 to energize a solenoid 24. A valve (not shown) in distributor 20 is then opened to allow fluid from fluid source 30 to flow through nozzle 26. The fluid distributed by the distributor 20 is heated by the reciprocating pump 31 to the heating hose 3
2, continuously circulated through the distributor 20, and the hose 34. The sensor 40 is fixed to the distributor 20.
A signal is provided that is indicative of fluid pressure within.

Distributor 20 is preferably of the type shown in U.S. Patent Application No. 339,730.

In the preferred embodiment of the first aspect of the invention, the sensor 40 is a transducer which provides an electrical signal indicative of detected pressure. The signal is transferred to monitor 15 via conductor 42. Monitor 1
5 also receives the actuation signal provided by distributor controller 22 via conductors 23 and 50. Each time the activation signal is issued, the monitor 15 compares the detected pressure signal with a pressure within a predetermined range. The pressure amplitude or value to which the sensor signal is compared is empirically determined to indicate that the nozzle 26 is clogged or worn.

As shown in FIG. 2, the switch 62 is a normally open switch that is closed during the operation signal period from the control device 22. When switch 62 is closed, the sensor signal passes to signal shaper 64, which converts the pressure signal into substantially pulsed form before being transferred to signal comparator 66.
The comparator 66 compares the amplitude of the pulse signal from the signal shaper 64 with a predetermined pressure value. If the magnitude of the shaped signal is outside the predetermined pressure value range, a malfunction signal is provided at output 68.

In the preferred embodiment of the first aspect of the invention, the monitor 15 also has an information processing device 70. The information processing device 70 receives the signal from the output 68 of the comparator and the actuation signal from the distributor control device 22 and, for example, increments a counter or gives an alarm audible by the user's ear or eye or by the partner. To occur.

In the embodiment relating to the second invention shown in FIG.
A sensor 5 receives an electric signal from a sensor 40 to a pre-shaper (not shown) via a conductor 42. The preshaper conventionally preamplifies the AC and DC components of the pressure signal from the sensor and inverts the pressure signal such that a pressure drop is indicated by a positive signal width.

The signal from distributor controller 22 is transferred to conductor 100 via conductor 50. Stretcher 100 causes the actuation signal of the control signals to be long or stretched in time. The stretched control signal causes the distributor 20 to close even after the distributor has actually closed. The actuation signal is prevented from being transmitted through the monitor 15. The stretched signal is then OR gate 19
9 to the second signal comparator 500 by means of a conductor 101. The output of OR gate 199 is in the form of a stretched pulse signal provided by conductor 101 if the signal on conductor 601 is low. Therefore, a signal substantially the same as the signal transferred from the stretcher 100 to the OR gate 199 is transferred to the switch and signal shaper 200, the first signal comparator 300, and the information processing device 600. Switch and signal shaper 200 performs substantially the same functions as switch 62 and signal shaper 64 described above and shown in detail in FIG. The first signal comparator 300 operates in a predetermined manner on the signal received via conductor 201 to the distributor 2.
It is compared with a pressure value of a predetermined width indicating 0. By this comparison, a malfunction signal is emitted and transferred to the information processing device 600 through the conductor 301. The first signal comparator 300 only acts on the signal from conductor 201 when the distributor 20 is activated by the distributor controller 22.

If the distributor is not activated by the distributor controller 22, the signal from the sensor 40 is representative of the third system and pump operation information. The pump circulates fluid from the fluid source through the distributor 20 and back to the fluid source. Pressure drop occurs between strokes when a continuous action reciprocating pump is incorporated into the system. Nordson Corporation, Amberst, Ohio
During proper operation with a pump such as that manufactured by, this pressure drop is approximately 30-40 psi. For example, when pump performance deteriorates due to worn seals, the pressure drop between strokes is approximately 100 to 200 psi. Therefore,
By comparing this signal with a predetermined pressure value indicating the pressure in the pump that is operating properly, proper performance can be monitored and mechanical defects such as wear seals can be detected. This is accomplished by passing the signal from the presheater to clamp 400. The clamp 400 holds down the DC component of the sensor signal from the pre-shaper and holds that portion of the signal when the pump is in stroke, i.e. when there is no pressure drop.
The part is clamped and held at zero value. The clamped signal is transferred to the second signal comparator 500 by the conductor 401.

The second signal comparator 500 also receives the stretched pulse signal from the conductor 101, and the second signal comparator is not activated when the distributor 20 is activated. Lead wire 401
If the clamped pressure signal from the
The signal comparator 500 outputs the malfunction signal to the information processing device 600.
Send to.

The information processing device 600 receives signals from the OR gate 199, the first signal comparator 300, and the second signal comparator 500. An embodiment of the information processing device 600 will be described in more detail below. The information processing device 600 indicates the type of malfunction or severity of malfunction and / or activates an alarm or other remedy. In FIG. 10, when a worn or clogged nozzle or a worn pump seal is detected, the information processing device 600 sends a signal to the OR gate 199,
Transfer to the first and second signal comparators 300 and 500 to prevent the monitor 15 from providing further output. In fact, the lead 601 is an OR gate 199, a non-actuated signal shaper 200
And the monitor 15 no longer provides a malfunction signal because it provides a high signal at the output of the first signal comparator 300. This situation continues until the monitor is reset, as described below in connection with the description of FIG.

FIG. 4 shows the above-mentioned preshaper including the preamplifier 80. The pressure signal is shaped by the arrangement of resistors and capacitors as shown in FIG. 4, and unnecessary nozzles are removed. The operation amplifier 90 (for example, TL084) operates only to increase the AC portion of the pressure signal. The signal appearing at point 96 is applied to the inputs of switch and signal shaper 200 and clamp 400. Suitable values for the resistors R ₁ , R ₂ , R ₃ and R ₄ are 1 kΩ, 2.2 kΩ, 100 kΩ and 51 kΩ respectively, and the capacitors C ₁ and C ₂ are 470 μF and 1 μF respectively.
Is.

FIG. 5 shows a specific example of the circuit of the switch and signal shaper 200. The signal from the precipiter is first filtered by the high-pass filter 201. The signal then passes through analog switch 206. In the position shown in FIG. 5, the analog switch 206 sends the signal from the precipitator to the operational amplifier (for example, TL084) 210, and the capacitor 21
8 is prevented from discharging to ground at point 208 and is instead charged by an arithmetic amplifier 210. When the signal at point 198 moves switch 206 to a position opposite that of FIG. 5,
Capacitor 218 discharges to ground. The calibration network work 228 is a calculation amplifier 220 (for example, TL).
084) to calibrate and hold a given voltage output. In this embodiment, when distributor 20 is operating properly, the output voltage of operational amplifier 220 is calibrated to 5 volts. The variable resistor 222 is adjusted for calibration, which affects the brightness of the light emitting diodes 252 and 262. When the light emitting diode has a substantially uniform brightness, the operational amplifier 220 is calibrated. The preferred values for the resistors and capacitors shown in FIG. 5 are as follows. R ₁ = 1 kΩ, R ₂ = 2.2 kΩ, R ₃ = 100 kΩ, R ₅ =
10 kΩ, R ₆ = 1 MΩ, 202; 0.47 μF, 204; 2
0 kΩ, 218; 0.47 μF. Further, a preferred example of the operation amplifier and the diode shown in FIG. 5 is as follows. Two
06; MC14053B, 210; TL084, 21
6; IN4148, 220; TL084, 230; TL
084, 240; TN4401, 250; 2N440.
3, 260; 2N4401, 254; 2N4403.

The pre-shaped signal transferred through conductor 201 is provided to a first signal comparator 300 shown in more detail in FIG. The signal from the conductor 201 is the comparator 310.
, And the positive input of the comparator 320. The reflected voltage applied to the comparators 310 and 320 sets a parameter of a predetermined pressure value range. The comparator 310 (for example, LM239) is connected to the point 3 when the input voltage from the lead wire 201
It is arranged as an inverting comparator so that its output remains at the voltage level at point 318 until it approaches the input voltage at 11. At point 311, comparator 310
Directs its output to ground. The reference voltage applied to input 311 is selected in the preferred embodiment by switch 316 connecting points AB, BC, or CD.

The comparator 320 is, for example, LM239 as shown in FIG.
And does not have an inverted output. Comparator 320
Causes the voltage at point 324 to change to resistor 326 and capacitor 3
The capacitor 330 will be charged according to the time constant given by 30. Capacitor 330 discharges through resistor 328 according to resistor 326 and the time constant associated with capacitor 330.

The outputs of the comparators 310 and 320 are OR gates 34.
Given to 0 input. This output is further OR gate 35.
0 input 354 is provided. Schmitt trigger 360
Reverses the output of OR gate 350, while Schmitt trigger 352 causes OR gate 199.
Invert the output from. In FIG. 6, suitable values for the resistor and the capacitor are R ₂ ; 2.2 kΩ, R ₅ ; 10 kΩ, R ₇ ;
27 kΩ, R ₈ ; 43 kΩ, R ₉ ; 39 kΩ, R ₁₀ ; 20 k
Ω, 328; 1 kΩ, 326; 10 kΩ, 330; 0.1
μF. Further, a comparator, an OR gate, a shift trigger and the like are preferably 310 and 320; LM23.
9, 340 and 350; MC14071B, 352 and 360; MC14584B.

Signals from distributor controller 22 of FIG. 1 are transferred via conductor 50 to the stretcher circuit of FIG. This circuit is mainly used for diode bridges (102, 104, 106).
And 108) and optical isolators (eg HIIA
I) 110. Capacitor 122 is charged according to the time constant associated with capacitor 122 and resistor 124. Then, a low output is produced on conductor 101 until the threshold of Schmitt trigger 130 is reached, which stretches the signal from distributor controller 22. Ground when low in this example. The time constant is chosen so that the output of the trigger 140 remains high until after the distributor 20 has actually closed. Suitable values for the resistors and capacitors in FIG. 7 are R ₁ ; 1 kΩ, R ₃ ; 100 kΩ, C ₃ ;
01 μF, 124; 100 kΩ, 122; 1 μF, 11
9; 43 kΩ.

The signal from the pre-shaper shown in FIG. 4 is applied to the input of the clamp 400 shown in FIG. 8 and is transferred to the second signal comparator 500 shown in FIG. The signal from lead 401 passes through the variable resistor to the positive input of comparator 510, which is connected as a basic comparator. The variable resistor is adjusted so that the voltage level of the pressure signal is 2.5 volts when the distributor is operating in proper condition. Therefore, when the signal from conductor 401 approaches the reference voltage of 2.5 volts in this embodiment, the output of comparator 510 goes from ground to an open circuit.

While the output of comparator 510 is grounded, the voltage at point 540 travels through the comparator to ground. When this output is an open circuit, the voltage at point 540 propagates through switch 530, closing it to point 534. Switch 530 is now closed and latched, and the voltage at point 540 is transferred to information processor 600 via conductor 501.

The output of OR gate 199, which propagates through diode 520, holds switch 530 in the position of FIG. 9 when distributor 20 is activated by the signal from distributor controller 22. The signal transferred from the stretcher 100 to the input of the OR gate 199 causes the output at point 198 to be low, subsequently holding the voltage at the output of the comparator 510 at a level insufficient for the switch 530 to reposition. . In FIGS. 8 and 9, preferably R ₁ ;
1 kΩ, R ₂ ; 2.2 kΩ, R ₅ ; 10 kΩ, R ₆ ; 1 MΩ,
R ₁₁ ; 4.7 kΩ, C ₂ ; 1 μF, C ₃ ; 0.01 μF, 410 and 510; LM239, 430; 2N4401, 530;
MC14053B.

FIG. 10 is a schematic diagram of a specific example of the information processing device 600.
This information processor counts the number of times the distributor has improperly dispensed material. Furthermore, this information processing device also indicates whether the detected pressure is above or below a predetermined pressure range, and also indicates whether the pump pressure is above a predetermined value. The information processing device 600 also provides a device for resetting the system after a malfunction is detected, and the monitor 15 stops providing further malfunction indications. The information processing device also provides at output 700 a signal to raise an alarm or to close the transport line moving the substrate under the dispenser.

The central processing unit 600 inputs the clock input to the OR gate 199.
It includes a counter 620 having as an output from.
The reset input of the counter is connected to conductor 301. Pins 11, 9, 6 and 5 are the multiple storage controller 630.
Connected to pins 4, 2, 5 and 12. Pin 1
The output of counter 620 at 1, 9 and 6 is also connected to inverter drivers 621, 622 and 623, respectively. The signal from the inverter driver 621 passes through diodes 624 and 625, which are IN4148 diodes in this example. Counter 62
A high signal appearing at pin 11 of 0 causes a low signal to appear at the output of the inverter driver 621, causing the voltage to flow through the light emitting diode 627 from point 631. Inverter drivers 622 and 623 operate similarly. In one embodiment, light emitting diodes 627, 628 and 629 correspond to a respective consecutive number of malfunctioning distributors 2, 4 and 8.

The output of the multiple storage controller 630 is connected to the input of the OR gate 650. The output of the OR gate 650 is connected to the driver inverter 660. In the present embodiment shown in FIG. 10, all driver inverters are Motorola MC11416B.

The output of the multiple storage controller 630 is also an OR gate 640.
Also provided to actuation inputs of A, 640B and 640C.
In this embodiment, OR gates 640A, 640B and 640C are configured so that no output appears at points QA, QB or QC unless the components are activated with the RS flip-flop included on a single electronic component. There is. A shift trigger inverter 604 is also used in this circuit.

The QA output of latch 640A is grounded and a normally low signal is provided to OR gate 199 whose output generally follows the input provided by stretcher 100. When latch 640A is not activated, the outputs at QA, QB and QC are observed as high impedance. Latch 6
When the output of 40B becomes high, the output of the driver 624 becomes low and the voltage applied to the point 648 becomes the light emitting diode 64.
It will flow through 5. The light emitting diode 646 is operated similarly.

When a high signal is applied to information processing device 600 via conductor 501, inverter driver 652 provides a low output, causing the voltage at point 656 to flow through light emitting diode 654.

A reset input is also provided so that inverter drivers 670 and 672 pass through diode 676 and lead 6
03 and through diode 674 to conductor 602, providing a high signal. Preferably in the embodiment of FIG.
R ₁ ; 1 kΩ, R ₅ ; 10 kΩ, R ₁₂ ; 470 Ω, 650;
MC14071B, 620; MC14024B, 63
0; MC14051B, 604; MC14584B, 6
40B; MC14044B.

FIG. 11 shows 4 at the point 96 of the presieper of FIG.
Two pressure waveforms are shown. Waveform A shows the pump pressure. Waveform B shows the fluid pressure within a predetermined range within the distributor. Waveform C shows fluid pressure in the distributor above a predetermined range, such as pressures of 60 psi and above, which typically indicate a worn nozzle. Waveform D represents the fluid pressure within distributor 20 below a predetermined range, such as a pressure of 40 psi or less, which indicates a clogged nozzle. The height of the waveform is shown in voltage and the length of the waveform is in time.

Waveform A shows the pressure drop detected during the stroke of the reciprocating piston pump described above. This signal is shown when distributor 20 is not operating, as shown by the waveform appearing at point 32. "Low" in the preferred embodiment of this second invention means that this signal is at zero volts or ground. If the signal at point 32 is continuously low, then the signal at point 198 is continuously high. Therefore, the latch 206 is in a position opposite to the position shown in FIG. Therefore, the waveforms appearing at points 207 and 219 are low signals. Since the signal at point 219 is continuously low, point 3
The outputs of comparators 310 and 320 at 18 and 321, respectively, are continuously high and continuously low. Subsequently, it continuously outputs a high output from OR gate 340.
Apply to point 354 at the input of R-gate 350. If the waveform at point 198 is continuously high, inverter 352 will provide a continuously low input to point 353 of OR gate 350. Therefore, the output of OR gate 350 is continuously high and
The waveform that appears on 1 is continuously low.

If the waveform at point 198 is high, the pump pressure will be
When the reference set within 10 is exceeded, the switch 530 in FIG. 9 is likely to change from the position shown to a point 534. For the sake of explanation, it is assumed that the waveform A exceeds a predetermined pressure value. Accordingly, point 198 is grounded and the pressure at point 540 flows through switch 530, latching the switch to point 534.

The waveform B in FIG. 11 shows an appropriate pressure condition in the distributor 20. Since the distributor is active, the signal at point 32 appears as shown. As mentioned above, the distributor 20 has an inherent mechanical delay between when the actuation signal is received and when the distributor actually opens. The same happens when closing. These are the periods 80 in FIG. 11, respectively.
0 and 801.

The signal appears at point 198 because distributor 20 is active. The stretched output at point 198 is shown at 802. Since the waveform at point 198 is low, switch 206
Is in the position shown in FIG. The waveform at point 207 is the 11th
Appears as shown and is detected by operational amplifier 210 charging capacitor 218. Therefore, point 21
The signal appearing at 9 indicates that the capacitor 218 is charging and discharging. Depending on the time of discharge, the output of the comparator 310 reaches low at point 318 until the capacitor is discharged so that the voltage is below the reference voltage provided at point 311. This period is 8 in FIG.
It is shown at 04. Since the voltage of the waveform at point 219 does not exceed the reference voltage at point 324 provided to comparator 320, the output at point 321 reaches a continuous low level. During the period 804, the OR gate 340 has inputs 342 and 34.
4 will have a low signal. As a result, the pulse appears in the waveform transferred by conductor 301. This pulse counts the rising edge of the waveform at point 198 and resets the counter 620 of FIG. This count is erased here,
No activation signal is provided to the latches 640A, B or C.

The waveform C indicates a high pressure drop in the distributor 20, for example, wear of the distributor nozzle in the coating process of the can. Since the distributor 20 is activated,
The same signals as for waveform B appear at points 32 and 198. The waveform appearing at point 207 is similar to that appearing in waveform B except for the amplitude. Therefore, the waveform appearing at point 219 is very similar to that of waveform B except that its amplitude is higher. This high signal at point 219 causes the output of comparator 310 at point 318 to be
It is similar to that of waveform B except that period 804 is slightly longer because 8 has been charged to a higher voltage. The pressure drop in waveform C is so large that it exceeds the reference voltage at point 324 for comparator 320, 324
The voltage at the point of time will charge the capacitor 330 according to the time constant of the resistor 326 and the capacitor 330. This signal appears at point 321. Capacitor 2 ensures that the input to comparator 320 is lower than the reference voltage at point 324.
When 18 is fully discharged, capacitor 330 discharges to ground through resistor 328 according to the time constants of capacitor 330 and resistor 328. Point 321 due to capacitor discharge
It is delayed that the voltage at becomes zero. It is OR gate 3
When a low signal is applied to the 40 inputs 344 and 342,
A low signal is applied to the input 354 of the OR gate 350 which causes the OR gate 350 to temporarily go low and the conductor 30
This is because a false pulse is given to 1. Therefore, resistance 3
The time constant set by 28 and capacitor 330 allows sufficient time for the signal at point 318, shown as 806 in FIG. 11, to return high. The resulting signal on conductor 301 is always low. Since no pulse appears on conductor 301, the counter 620 of the information processor is not reset and the rising edge at point 198 counts the counter.

If the counter 620 measures a predetermined number of consecutive numbers from the OR gate 199, the signal is transferred to the OR gate 199 through the multiplex storage device 630, and the latches 640A, 640B.
And C. Point RA of latch 640A receives a high signal and point SA receives a low signal, providing a high output at point QA. The shift trigger inverter 604 is also a conductor 6.
A high signal is provided to the negative input of the multiple storage device 630 through 05. Since the output of QA is high, the output of OR gate 199 will reach high, "freezing" the system.

When the operation signal is given by the multiple storage device, the latch 6
40C gives high input at RC with respect to waveform C, and also QC
SC gives a low output, and SC gives a high input. The low output at QC gives a high input at SB, is inverted by the inverter triber 644, and then gives a low input at RB.
Give B a high output. It is indicated that the subsequent actuation of light emitting diode 645 caused a high pressure drop.

Waveform D in FIG. 11 shows the pressure drop across distributor 20 which is too low to indicate a blockage. Since distributor 20 is in operation, the signals shown in more detail in waveform B occur at points 32 and 198. Switch 206 is at the position shown in the figure and is point 2
There is a waveform at 07. A waveform appears at point 219 due to the charging of capacitor 218. The signal at point 219 is relatively small in amplitude so that it is not close to either of the reference voltages for comparator 310 or 320, resulting in point 3
The output at 18 reaches high and the waveform at point 321 reaches low for full operation. High-low signal is OR gate 340
, The high output appears at the input 354 of the OR gate 350. Accordingly, OR gate 350 has a high output which provides a low output on conductor 301 by a shift trigger inverter 360. As mentioned above, conductor 3
The low signal on 01 causes the counter 620 to OR gate 1
99 pulse signals will be counted. If waveform D indicates the appropriate number of consecutive counts by counter 620, then multiple store 630 provides a high signal to OR gate 650 to activate latches 640A, B and C. As the output of comparator 310 reaches high continuously, a low signal is applied to the RC input of latch 640C. As before, a high signal is received at the input SC. In a preferred embodiment of the second aspect of the invention, the inverter is a latch 6
Each of the 40A, B and C inputs and the fourth unused latch input, not shown, in the set is placed before it is connected to ground. Once activated, the latch 640C has a high output at QC. The operation of the light emitting diode indicates that the pressure drop across the distributor 20 is too small.

It will be easily understood by those skilled in the art that other changes and modifications can be made within the scope of the present invention, and the present invention is not limited to the above embodiments.

EFFECTS OF THE INVENTION According to the spray gun monitoring device of the present invention, it can be quickly and automatically determined that the paint is no longer properly sprayed from the spray gun.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a system showing an embodiment of the first invention,
FIG. 2 is a block diagram of the monitor of FIG. 1, and FIG.
FIG. 4 is a block diagram showing another embodiment of the invention, FIG. 4 is a circuit diagram of the pre-shaper circuit of FIG. 3, FIG. 5 is a circuit diagram of the switch and signal shaper of FIG. 3, and FIG. 6 is of FIG. The circuit diagram of the first signal comparator, FIG. 7 is the circuit diagram of the stretcher of FIG. 3, FIG. 8 is the circuit diagram of the clamp of FIG. 3, and FIG.
FIG. 10 is a circuit diagram of the second signal comparator in FIG. 10, FIG. 10 is a circuit diagram of the information processing device in FIG. 3, and FIG. 11 is from FIG. 4 in different phases of the distribution operation at different points in FIG. FIG. 6 is a waveform chart under different distribution conditions. [Description of symbols of main parts] 15 ... Monitor 64 ... Signal shaper 300 ... First signal comparator 22 ... Distributor (spray gun) control device 66 ... Comparator 500 ... Second signal comparator 40 …… Sensor 70,600 …… Information processing device 400 …… Clamp 26 …… Nozzle 100 …… Stretcher 200 …… Switch and signal shaper 20 …… Distributor (spray gun) 62 …… Switch

Claims (9)

[Claims] 1. A spray gun (20) for spraying paint under pressure, and a control means (22) for giving an operation signal to the spray gun (20) for controlling the opening / closing conditions of the spray gun (20). And a monitor for evaluating the operation of a spray gun, which is used in a coating system having a pressure sensor, and which detects a fluid pressure of paint inside the spray gun (20) and generates a pressure signal representing the fluid pressure. Detection means (4
0) and monitor means (15) connected to receive the pressure signal and the actuation signal, the monitor means being connected to receive the pressure signal and having a first end connected to the pressure signal. When the control means gives an operation signal for opening the spray gun, the one pressure value and a predetermined pressure value range having a second pressure value at the other end are compared, and when the pressure signal is outside the pressure value range. A spray gun monitoring device comprising a comparison means (66) for generating a malfunction signal. 2. The spray according to claim 1, wherein the spray gun includes a nozzle having an opening through which the paint is sprayed, and the first pressure value represents clogging of the opening. Gun monitoring device. 3. The spray gun includes a nozzle having an opening through which the paint is sprayed, and the second predetermined pressure value indicates that the opening is worn. The spray gun monitoring device according to the item. 4. The pressure signal is an electrical signal, connected to receive the pressure signal, to substantially shape the pressure signal into pulses and to transfer the shaped pressure signal to the comparison means. The spray gun monitoring device according to claim 1, further comprising shaping means. 5. A switch for connecting the monitoring means to the shaping means when connected to receive the pressure signal and the actuation signal and when the actuation signal indicates opening of the spray gun. The spray gun monitoring device according to claim 4, further comprising means. 6. The actuation signal and the malfunction signal by connecting to receive the actuation signal and the malfunction signal, counting each malfunction of the spray gun and generating a signal representative of this count. The spray gun monitoring device according to claim 1, further comprising an information processing unit for processing the spray gun. 7. The detection means (40) generates an electrical pressure signal as the pressure signal, and the monitoring means (15) is connected to receive the electrical pressure signal and the electrical pressure signal Spray gun (2
Shaping means (64) for shaping into an analog pulse signal which is approximately proportional to the corresponding portion of the pressure signal indicating the open state of (0).
Is connected to receive the adjusted analog signal, comparing the analog signal with first and second predetermined analog values when the actuation signal indicates opening of the spray gun, and the analog signal is the first analog signal. Means for generating a malfunction signal indicating that it is not between the second analog value and the second analog value (6
6) and Claim 1 characterized by the above-mentioned.
The spray gun monitoring device according to the item. 8. A spray gun (20) for spraying paint under pressure, and a control means (22) for giving an operation signal to the spray gun (20) for controlling the opening / closing conditions of the spray gun (20). And a monitoring device for evaluating the spray gun operation, the pressure signal representing the fluid pressure of the paint inside the spray gun (20) being detected by the fluid pressure of the paint. Generating means for detecting (40), the pressure signal and the first and second predetermined pressures being connected to receive the pressure signal and the actuation signal, the actuation signal indicating the opening of the spray gun (20). A first comparing means (300) for comparing the pressure signal and a pressure signal indicating that the pressure signal is not between the first and second pressures, and the pressure signal and the actuation signal. And connected to receive Second comparing means for comparing the signal with a third predetermined pressure value and for generating a malfunction signal representative of the pressure signal exceeding a third pressure value when the actuation signal indicates a non-actuated state of the spray gun. (500) and a spray gun monitoring device. 9. Clamping means connected between said detecting means and said second comparing means for clamping said sensor signal such that said sensor signal is only positive. The spray gun monitoring device according to claim 8.