JPH06339890A - Internal pressure explosion-proof mechanism - Google Patents

Abstract

PURPOSE:To simplify a wiring system or the like by making common use of an electric wire of a solenoid valve to open and close an exhaust hole of an external frame and an explosion-proof object apparatus when infiltration of flammable gas is prevented while maintaining the inside of the external frame to shield the explosion-proof object apparatus in a high pressure condition. CONSTITUTION:When painting work is carried out by a robot 1, since explosive gas happens to generate from paint or the like, the robot 1 is shielded by an external frame 2. Before the painting work is carried out, explosion-proof work is carried out. That is, a hand valve 61 of an air pipe 60 is opened, and air is supplied inside of the external frame 2 from an air inlet hole 52. At the same time, a solenoid valve 51 is opened, and the air in the external frame 2 is discharged from an exhaust hole 50. When a pressure detector 53S detects that air pressure in the external frame 2 reaches an upper limit value, an electric current is carried to a robot control device 10 or the like by a protective monitoring device 20 after prescribed timer time passed. The solenoid valve 51 is closed, and the air pressure in the external frame 2 is held under high pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal pressure explosion-proof mechanism, which is devised so that an air supply system and a wiring system can be simplified.

[0002]

2. Description of the Related Art When painting by a robot,
Explosive (or flammable) gas may be generated from paints, etc. In this case, the robot must have an explosion-proof structure.

FIG. 2 shows a robot apparatus having an internal pressure explosion-proof structure. In the figure, the dotted line shows the electric wire,
The solid line indicates the air pipe. In addition, the members with "S" added to the reference numeral are intrinsically safe members, that is, members for which measures are taken such as reducing the power consumption so that the flammable gas does not ignite even if a short circuit occurs.

As shown in FIG. 2, the robot 1 is installed in a dangerous place where flammable gas or the like exists, and the robot controller 1
0 and the protection and monitoring device 20 are installed in a non-hazardous area where flammable gas or the like does not exist.

The robot 1 is provided with an electric part (servo motor, various sensors, etc.) 3 in an external frame 2. The electric wires L ₁ and L ₂ electrically connect the robot control device 10 and the electric part 3 of the robot 1 via the shields 4 and 5, and the signals between the robot control device 10 and the electric part 3 are electrically connected. Transmission and reception is performed by the electric wire L ₁ , and electric power is supplied from the robot controller 10 to the electric part 3 by the electric wire L ₂ .

On the outer frame 2 of the robot 1, an upper limit pressure detector (essentially safe type) 30S, a lower limit pressure detector 31,
A relief valve 32, a normally open solenoid valve 33, and air supply holes 34 and 35 are provided. Air is supplied to the air supply holes 34 and 35 from an air source (not shown) via an air pipe 36 and pipes 36H and 36L branched from the air pipe 36. The air pipe 36 has a hand valve 37,
A filter 38 and a pressure reducing valve 39 are installed, and pressure reducing valves 40 and 41 are installed in the branched pipes 36H and 36L. The air supply hole 34 is connected to the solenoid valve 33.

The solenoid valve 33 is de-energized and is in the open state.
If the hand valve 37 is opened while the
Air is supplied from the air holes 34) and the air supply holes 35. D
Ah pressure is P₁, P₂, P₃, P_Four(However, P₁> P₂>
P₃> P_Four> Atmospheric pressure), blow from the solenoid valve 33
The air pressure to output is P₁And blow out from the air supply hole 35.
Earth pressure is P₃So that the pressure reducing valves 39, 40, 41 are
Has been adjusted. The relief valve 32 is an external frame.
The air pressure in 2 (air pressure in the frame) is P₂And above
The upper limit pressure detector 30S opens when the air pressure in the frame
Is P₂When the above is reached, the detection signal DP₂Output, lower limit pressure
For the force detector 31, the air pressure in the frame is P _FourBecame below
Detection signal DP_FourIs output.

The protection monitoring device 20 comprises a protection monitoring section 21 and an intrinsically safe barrier relay (intrinsically safe type) 22S. The protection monitoring unit 20 uses the electric wire L ₄ to control the solenoid valve 3
When the detection signal DP ₄ is received from the lower limit pressure detector 31 via the electric wire L ₃ while controlling the excitation / de-excitation of No. 3, the power supply to the robot control unit 10 and the robot 1 is cut off. The intrinsically safe barrier relay 22S receives the detection signal DP ₁ from the upper limit pressure detector 30S via the electric wire L ₅ .

In the robot apparatus having the above-mentioned internal pressure explosion-proof structure, before the actual operation of the robot 1, the explosion-proof work is performed to prevent the flammable gas from entering the outer frame 2. That is, the hand valve 37 is opened to supply air into the outer frame 42. When the air pressure in the frame exceeds P ₂ , air is discharged from the relief valve 32. Therefore, the outside air guided from the non-hazardous area enters the outer frame 2 and the air in the frame is discharged to perform the scavenging. When the in-frame air pressure reaches P ₂ , the detection signal DP ₂ is output from the upper limit pressure detector 30S, and the protection monitoring device 20 starts counting the timer. The inside of the outer frame 2 and the air pipes 36, 36H, 36L
The time required to be scavenged with five times or more of the volume of air is preset as the timer time. Therefore, when the timer time elapses after the timer starts counting, the protection monitoring unit 21 is excited and the solenoid valve 3 is excited.
Close 3 to complete scavenging.

When the scavenging is completed, the robot controller 10
The robot 1 is operated. Even while the robot 1 is operating
Air pressure is P from the air pipe 36L₃Became air
Will be supplied to the outside unless there is a special accident or defect.
Air pressure in frame 2 is P ₃Held above.

When some kind of accident or defect occurs, the air pressure in the outer frame 2 is lowered, and when the air pressure becomes lower than P ₄ , the lower limit pressure detector 31 outputs a detection signal DP ₄ . When the air pressure in the frame becomes P ₄ or less, flammable gas or the like may enter the outer frame 2. To prevent ignition and explosion. It also issues an emergency warning.

[0012]

By the way, in the prior art shown in FIG. 2, two branched air pipes 36H, 36 are provided.
Due to L, air must be supplied into the outer frame 2, which complicates the air system. Moreover, since three electric wires L3, L4, and L5 are required for transmitting signals and electric power between the protection monitoring device 20 and the robot 1, the wiring system becomes complicated.

[0013]

The structure of the present invention for solving the above-mentioned problems is to be installed in a hazardous area and to be installed in a non-hazardous area with an explosion-proof device to which air is supplied in an external frame. An internal pressure having a control device that supplies a command signal and power to the explosion protection target device, and a protection monitoring device that shuts off the power supply of the control device and the explosion protection target device when the air pressure in the external frame drops below a certain value. In the explosion-proof mechanism, one air pipe for supplying air into the external frame, a pressure detector that detects the air pressure in the external frame and sends a detection signal corresponding to the air pressure to the protection monitoring device, It is installed in the outer frame, and when it is in the open state, the inside and the outside of the outer frame are in communication with each other, and it is excited by the electric power sent to the explosion-proof mechanism to be in the closed state. Characterized by comprising a chromatography circle open type electromagnetic valve.

[0014]

Since the solenoid valve for opening to the atmosphere is excited by the electric power sent to the explosion-proof target device (robot), the power supply and excitation wires can be shared and the wiring system can be simplified. Further, since the air is supplied to the explosion-proof device by one air pipe, the air system can be simplified.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. It should be noted that parts having the same functions as those of the conventional technique are denoted by the same reference numerals, and redundant description will be omitted.

FIG. 1 shows an embodiment of the present invention. As shown in the figure, the robot controller 10 and the electric part 3 of the robot 1
Signals are exchanged with the electric wire L ₁ , and electric power is supplied from the robot control unit 10 with the electric wire L ₂ .

The outer frame 2 of the robot 1 is provided with an exhaust hole 50, a solenoid valve 51, an air supply hole 52, and a pressure detector 53S. Solenoid valve 51 is disposed in the internal space of the outer frame 2, a normally open type that coil 51a is connected to the wire L ₂ for power, the valve 51b is communicated with the exhaust hole 50. The electric wire L ₂ has a function of supplying electric power to the electric part 3 and a function of sending a current for exciting the coil 51 a of the solenoid valve 51. The pressure detector 53S detects the air pressure inside the outer frame 2, and a detection signal D corresponding to the detected air pressure inside the frame.
P is the intrinsic safety barrier relay 22S of the protection and monitoring device 20.
Send to.

One air pipe 60 is provided in the air supply hole 52.
Air is supplied from an air source (not shown) via. The pipe 60 has a hand brub 61 and a filter 6
2. A pressure reducer 63 is provided.

In the robot apparatus of the present invention having the above-mentioned internal pressure explosion-proof structure, the explosion-proof work before the actual work is performed as follows. That is, the hand valve 61 is opened to supply air into the outer frame 2. At this time, the robot controller 10
Also, since the power supply of the robot 1 is cut off in advance, the valve 51b of the solenoid valve 51 is in an open state, and as the air is supplied to the outer frame 2, the air in the frame is released to the outside via the valve 51b and the exhaust hole 50. It is discharged to and the scavenging is executed.

When the pressure detector 53S detects that the air pressure in the frame has reached the upper limit value P _max , the protection monitoring device 2
At 0, the timer starts counting. The time required for the inside of the outer frame 2 and the inside of the pipe 60 to be scavenged with air whose volume is 5 times or more is preset as the timer time. Therefore, the protection monitoring unit 21 turns on the power supplies of the robot control device 10 and the robot 1 when the timer time has elapsed after the timer starts counting.

Then, a current flows through the electric wire L ₂ to excite the coil 51a of the solenoid valve 51 and close the valve 51b. Therefore, the air pressure in the outer frame 2 is kept higher than the atmospheric pressure. Therefore, the flammable gas cannot enter the outer frame 2.

External frame 2 due to some accident or failure
When the pressure detector 53S detects that the internal air pressure has fallen below the lower limit P _min , the protection monitoring device 20 shuts off the power supply of the robot control device 10 and the robot 1.

In this embodiment, the coil 51a of the solenoid valve 51 is
Since the electric wire L ₂ used for exciting the electric field and the electric wire L ₂ used for supplying electric power to the electric part 3 are commonly used,
The number of wires can be reduced accordingly. Further, it is not necessary to branch the air pipe, and only one air pipe 60 is required.

The present invention can be applied not only to the robot device but also to other explosion-proof electronic and electric devices.

[0025]

According to the present invention, as described in detail with reference to the embodiments, the air system and the wiring system can be simplified and the structure is simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional technique.

[Explanation of symbols]

 1 Robot 2 External Frame 3 Electrical Part 4, 5 Shield 10 Robot Controller 20 Protection Monitoring Device 21 Protection Monitoring Unit 22S Intrinsically Safe Barrier Relay 30S Upper Limit Pressure Detector 31 Lower Limit Pressure Detector 32 Relief Valve 33 Solenoid Valve 34, 35 Air Supply Hole 36,36H, 36L Air pipe 37 Hand valve 38 Filter 39,40,41 Pressure reducing valve

Claims (1)

[Claims] 1. An explosion-proof device which is installed in a hazardous area and is supplied with air into an external frame, and a control device which is installed in a non-hazardous area and supplies a command signal and power to the explosion-proof device. In an internal pressure explosion-proof mechanism having a protection monitoring device that shuts off the power supply of the control device and the explosion-proof target device when the air pressure in the external frame drops below a certain value, one that supplies air into the external frame Of the air pipe, a pressure detector that detects the air pressure in the outer frame and sends a detection signal according to the air pressure to the protection and monitoring device, and the inside and outside of the outer frame when installed in the outer frame and open. And a normally open solenoid valve that is closed by being excited by electric power sent to the explosion-proof target mechanism. Internal pressure explosion-proof mechanism.