JP2796482B2 - Internal pressure explosion-proof mechanism - Google Patents

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 designed so that an air supply system and a wiring system can be simplified.

[0002]

2. Description of the Related Art When painting with a robot,
An explosive (or flammable) gas may be generated from paint or the like, and in this case, the robot needs to have an explosion-proof structure.

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

[0004] As shown in FIG. 2, the robot 1 is installed in a danger area where a flammable gas or the like exists, and the robot controller 1
0 and the protection monitoring device 20 are installed in a non-hazardous area where no flammable gas or the like exists.

The robot 1 has 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 controller 10 and the electric part 3 of the robot 1 via the shields 4 and 5, and signal transmission between the robot controller 10 and the electric part 3 is performed. exchange is carried out in the wire L _1, power supply from the robot controller 10 to the electric part 3 is carried out in the wire L _2.

The outer frame 2 of the robot 1 has an upper limit pressure detector (intrinsically 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 provided, and pressure reducing valves 40 and 41 are provided 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 becomes open.
When the hand valve 37 is opened while the
Air is supplied from the air holes 34) and the air supply holes 35. D
Pressure is P₁, P_Two, P_Three, P_Four(However, P₁> P_Two>
P_Three> P_Four> Atmospheric pressure), blows from solenoid valve 33
Air pressure is P₁And blows out from the air supply hole 35.
Pressure is P_ThreeSo that the pressure reducing valves 39, 40, 41
Has been adjusted. Also, the relief valve 32 is connected to an external frame.
Air pressure in 2 (air pressure in frame) is P_TwoOver
Open, and the upper limit pressure detector 30S
Is P_TwoWhen the above occurs, the detection signal DP_TwoIs output and the lower limit pressure
When the air pressure in the frame is P _FourBecame
Detection signal DP_FourIs output.

[0008] The protection monitoring device 20 comprises a protection monitoring unit 21 and an intrinsically safe barrier relay (intrinsically safe type) 22S. Protection monitoring unit 20, the electromagnetic valve 3 through the wire L ₄
3 controls the excitation and non-excitation of, when receiving a detection signal DP ₄ from the lower limit pressure detector 31 through an electric wire L _3, to cut off the power supply to the robot control unit 10 and the robot 1. The intrinsically safe barrier relays 22S receives the detection signal DP ₁ from the upper limit pressure detector 30S through an electric wire L _5.

In the robot apparatus having the above-mentioned internal pressure explosion-proof structure, an explosion-proof operation for preventing flammable gas from entering the outer frame 2 is performed before the actual operation of the robot 1. That is, the hand valve 37 is opened to supply air into the outer frame 42. Frame air pressure air is discharged from the relief valve 32 exceeds P _2. Therefore, the outside air led from the non-hazardous place enters the outer frame 2 and the air in the frame is discharged to perform scavenging. Frame air pressure is output the detection signal DP ₂ from the upper limit pressure detector 30S When turned P _2, start the counting of the protection monitoring device 20 in timer. The inside of the outer frame 2 and the air pipes 36, 36H, 36L
The time required for the air to be scavenged by the air of 5 times or more of the volume is preset as a timer time. Therefore, when the timer time elapses after the timer starts counting, the protection monitoring unit 21 excites the solenoid valve 3.
3 is closed to complete the scavenging.

When the scavenging is completed, the robot controller 10
The robot 1 is operated more. Even when the robot 1 is operating
Air pressure is P from air pipe 36L_ThreeBecame air
Are supplied, unless there is a special accident or defect.
Air pressure in frame 2 is P _ThreeIt is held above.

When an accident or failure occurs, the air pressure in the outer frame 2 decreases and when the air pressure becomes lower than P ₄ , a detection signal DP ₄ is output from the lower limit pressure detector 31. Since the intraframe air pressure is P ₄ below flammable gas or the like there arises a possibility of entering into the outer frame 2, the protection monitoring device 20 powers down the robot control unit 10 and the robot 1, short circuit or the like To prevent ignition and explosion. In addition, an emergency warning is issued.

[0012]

In the prior art shown in FIG. 2, two branched air pipes 36H and 36H are provided.
Due to L, air must be supplied into the outer frame 2 and the air system becomes complicated. Further, 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]

Means for Solving the Problems The constitution of the present invention which solves the above-mentioned problem is that an explosion-proof equipment which is installed in a danger area and air is supplied into an external frame, and which is installed in a non-dangerous area, An internal pressure, comprising: a control device that supplies a command signal and power to the explosion-proof device; and a protection monitoring device that shuts off the power of the control device and the explosion-proof device when the air pressure in the external frame falls below a certain value. In the explosion-proof mechanism, one air pipe that supplies air into the external frame, a pressure detector that detects 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 in the open state, it connects the inside and the outside of the outer frame to the communicating state, and is closed by being excited by the power sent to the explosion-proof mechanism. Characterized by comprising a chromatography circle open type electromagnetic valve.

[0014]

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

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. The parts performing the same functions as those of the prior art are denoted by the same reference numerals, and overlapping 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
Signal exchange between was carried out by the wire L _1, the supply of power from the robot control unit 10 is performed by wire L _2.

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

The air supply hole 52 has a single air pipe 60.
Air is supplied from an air source (not shown) via the. The pipe 60 includes a hand valve 61 and a filter 6.
2. A decompressor 63 is interposed.

In the robot apparatus of the present invention having the above-mentioned internal pressure explosion-proof structure, the explosion-proof operation before the actual operation 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
Since the power supply of the robot 1 is shut off in advance, the valve 51b of the solenoid valve 51 is in an open state. As the air is supplied to the external frame 2, the air in the frame is externally discharged through the valve 51b and the exhaust hole 50. And scavenging is performed.

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

[0021] Then the coil 51a of the electromagnetic valve 51 a current through the wire L ₂ is energized valve 51b is closed. For this reason, 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.

The external frame 2 due to any accident or failure
When the pressure detector 53S detects that the air pressure in the inside falls below the lower limit value _Pmin , 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
Since the wire L ₂ used for excitation, and shared the wire L ₂ used to power the electric part 3,
The number of electric wires can be reduced accordingly. In addition, there is no need to branch the air pipe, and only one air pipe 60 is required.

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

[0025]

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

[Brief description of the 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]

 REFERENCE SIGNS LIST 1 robot 2 outer frame 3 electric 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)

(57) [Claims] An explosion-proof device installed in a hazardous area and supplied with air in an external frame, a control device installed in a non-hazardous location and supplying a command signal and power to the explosion-proof device. An internal pressure explosion-proof mechanism, comprising: a protection monitoring device that shuts off power to the control device and the explosion-proof equipment when the air pressure in the external frame falls below a certain value. An air pipe, a pressure detector that detects an air pressure in the outer frame and sends a detection signal corresponding to the air pressure to the protection monitoring device, and a pressure detector installed in the outer frame and inside and outside the outer frame when opened. And a normally open solenoid valve which is closed by being excited by the electric power sent to the explosion-proof mechanism. Internal pressure explosion-proof mechanism.