KR100320998B1 - A explosion and flame proof control switch box - Google Patents

Abstract

The present invention relates to an explosion-proof control switch box, a conventional explosion-proof control switch box is the explosion-proof gas is introduced into the box through the opening covered by the transparent panel for visually confirming the current value of the power supply safety of explosion-proof The explosion-proof control switch box of the present invention has an explosion-proof housing structure by combining the upper case and the lower case formed with a power cable connection hole, and has a plurality of select switches and select switches inside the upper and lower cases. In the explosion-proof control switch box formed with an ammeter for measuring the current value of the power applied from the outside, a transparent panel for visually checking the current value measured by the ammeter is formed on the upper case, the transparent panel is integrated with the upper case To form.

Therefore, when used in a dangerous area has the effect of blocking the introduction of external explosive gas to the inside to significantly reduce the risk of explosion and fire when sparks occur.

Description

Explosion proof control switch box {A explosion and flame proof control switch box}

The present invention relates to an explosion-proof control switch box, and in particular, an explosion-proof control switch box that improves the sealing and sealing properties which are characteristics of the explosion-proof to reduce the risk of explosion and fire.

There is always a risk of explosions and fires in oil refineries, gas refineries and plants handling flammable materials.

Therefore, these hazardous areas are classified according to their risk status in international conventions such as the National Electric Code (NEC) or the International Electrotechnical Committee (IEC).

As a representative example of this classification, the dangerous place is divided into three places.The place where the dangerous atmosphere is continuously generated or is likely to occur in the normal state is classified as 0 places and the place where the dangerous atmosphere may occur in the ordinary place. There are three kinds of places, one place and the place where dangerous atmosphere can exist for a short time under abnormal conditions.

There are always risks of explosions and fires in places 0 and 1 of these hazardous areas, so electrical devices (power cables, switches and switch boxes, connectors, etc.) used in these areas may have sparked or unsafe power connections. If this occurs, it will soon cause an explosion and fire, so that electrical devices require a means to ensure that they are not particularly exposed to the risk of explosion and fire.

Such means uses an explosion-proof structure that seals and seals an electrical device.

1 and 2 are front and cross-sectional views of an explosion-proof switch box used in a hazardous area where explosion and fire hazards exist by using such an explosion-proof structure, and the unexplained reference numeral 13 is for showing a stepped portion. Reference numeral 22 is for showing the adhesive.

Referring to the conventional explosion-proof switch box with reference to the explosion-proof switch box is formed of a polyester (Polyester) material is formed of the upper, lower case (10, 11) having an explosion-proof housing structure sealed and sealed inside when combined.

Push buttons 15 and 16 for on / off operation are formed on the upper surface 10-1 of the upper case 10 so as to be operated up and down, and contacts not shown inside the lower case 11 are united. Selected switches 19 and 20 that are explosion-proof and are connected to the up and down operations of the push buttons 15 and 16 operated on / off to short-circuit or open the contacts to apply power. Is located.

In addition, an ammeter 21 is installed inside the lower case 11 to measure the current of the power applied to the selection switch 19, and on one side of the lower case 11, an external power cable not shown is pulled out. In order to connect the selection switches 19 and 20, cable connection holes 14 are formed.

Here, a screw thread is formed in the cable connection hole 14 and is screwed together with the power cable.

In addition, the measured value of the ammeter 21 for measuring the current value of the power source connected to the selection switch 19 through the cable connection hole 14 on a predetermined portion of the upper surface 10-1 of the upper case 10 is visually displayed. Opening 12 is opened to a predetermined width and width to confirm with.

The inside of the opening 12 is stepped in a stepped manner, and the step portion 13 covers the opening 12 so as to prevent external explosive gas from being introduced through the opening 12. Is bonded with an adhesive material such as adhesive 22 to cover the opening.

Accordingly, the explosion-proof control switch box connects an external power cable to the selection switches 19 and 20 through the cable connection hole 14, and the power is supplied according to the up and down operations of the push buttons 15 and 16. FIG. The current value of the power applied to the ammeter 21 while being applied or cut off is measured, and the measured current value is visually confirmed through the transparent panel 17 of the opening 12.

However, such a conventional explosion-proof control switch box has a problem that the explosion-proof of the transparent panel for visually confirming the current value of the power source measured by the ammeter is unstable.

In other words, the transparent panel is adhered to the stepped step of the opening with an adhesive or the like to cover the opening and explosion-proof.However, the transparent panel is dropped or the sealing property is degraded due to the adhesive thickness of the adhesive and the poor adhesion of the adhesive. Through the opening, it is introduced into the explosion-proof control switch box, which increases the risk of explosion and fire in the event of a spark.

In addition, the conventional explosion-proof control switch box has a problem that wears when connecting the power cable frequent screw thread of the cable connection hole.

That is, since the thread of the cable connection hole is formed in the lower case made of polyester material, when the thread of the power cable is mutually screwed together, the thread of weak strength is worn out and the explosive gas flows into the worn thread, causing the explosion and fire. The risk is rich.

Accordingly, the present invention has been made in order to solve the problems of the prior art, by completely blocking the outside gas introduced through the opening and the cable connection hole that is covered by the transparent panel covering the explosion and The purpose is to provide an explosion-proof control switch box that eliminates the risk of fire.

Therefore, in order to achieve the above object, the present invention has an explosion-proof housing structure in which the upper case and the lower case formed with the power cable connection hole are coupled to each other, and the upper and lower cases are applied from the outside with a plurality of selection switches and the selection switch. In the explosion-proof control switch box is formed with an ammeter for measuring the current value of the power supply, a transparent panel that can visually check the current value measured by the ammeter on the upper case, but the transparent panel is formed integrally with the upper case .

In addition, a threaded metal bushing is attached to the power cable connection hole of the lower case, but the bushing is integrally formed with the lower case.

1 is a front view of a conventional explosion-proof control switch box,

2 is a cross-sectional view of the <II-II '> direction of FIG.

3 is a front view of the explosion-proof control switch box of the present invention,

FIG. 4 is a cross-sectional view of the <IV-IV '> direction in FIG.

■ Brief description of the main parts of the drawing ■

10,11: Case 12,100: Opening

14: cable connection hole 15, 16: push button

17,101: transparent panel 19,20: selection switch

21 Ammeter 102 Bushing

Hereinafter, with reference to the accompanying drawings illustrating a preferred embodiment of the present invention explosion-proof control switch box as follows.

First, FIG. 3 is a front view of the explosion-proof control switch of the present invention, and FIG. 4 is a cross-sectional view of the <IV-IV '> direction of FIG. 3 for explaining the inside of the explosion-proof control switch of the present invention.

The explosion-proof switch box of the present invention is formed of a polyester (Polyester) material, the lower case (10, 11) is formed in an explosion-proof housing (housing) structure for sealing and sealing the inside.

Upper and lower push buttons 15 and 16 are formed on the upper surface 10-1 of the upper case for the on / off operation, and the push buttons 15 and 16 of the lower case 11 are formed inside the upper case 10. Select switches 19 and 20 are positioned to apply power by shorting or opening internal contacts, which are not shown, in conjunction with up and down operations.

In more detail, when the push button 15 for turning on the power is pressed, the internal contacts of the selector switch 19 are short-circuited to each other so that the power is applied, and the push button for turning the power off ( When 16) is pressed, the internal contacts of the selector switch 20 are opened to shut off power.

In addition, an ammeter 21 is installed inside the lower case 11 to measure a current value of the power applied to the selection switch 19, and an external power cable not shown on one side of the lower case 11 is provided. Cable connection holes 14 are formed to draw inside the lower case 11 and connect the selection switches 19 and 20, respectively. Here, the cable connection hole 14 is provided with a threaded metal bushing 102, the bushing 102 is molded at the same time molding the polyester (polyester) as the molding material during the injection molding of the lower case 11 (cable connection) To be installed in the ball (14).

Therefore, when the external power cable is not inserted into the cable connection hole 14 and installed, the power cable and the bushing 102 made of metal are mutually screwed together, and thus, wear of the thread is suppressed to block external gas from being introduced. Done.

In addition, a power cable not shown in the upper case 10 is drawn into the lower case 11 through the cable connection hole 14 and the bushing 101 to be connected to and applied to the selection switches 19 and 20, respectively. In order to visually confirm the current value measured by the ammeter 21 for measuring the current value of the power source from the outside, an opening 100 opened in a predetermined width and width is formed.

In this opening 100, a transparent panel 101 is formed to cover the opening and prevent an external explosive gas from being introduced through the opening 100, and the transparent panel 101 is ejected from the upper case 10. At the time of molding, it is molded at the same time as polyester (polyester) as a molding material to be formed integrally with each other in the upper case (10).

Accordingly, the transparent panel 101 integrally formed with the upper case 10 blocks the opening 100 from being introduced through the opening 100 to completely cover the opening 100, and the transparent panel 101 falls down. Will be prevented.

The explosion-proof control switch box of the present invention having such a structure, even when used in a dangerous area where the risk of explosion and fire is high, is not drawn into the explosion-proof control switch box to significantly reduce the risk of explosion and fire. do.

As described above, the explosion-proof control switch box of the present invention blocks the inflow of the outside air through the opening in which the transparent panel for visually confirming the current value of the applied power source, and the thread in the cable connection hole By installing the formed metal bushing to prevent the wear of the thread when connecting the power cable, it prevents the introduction of external explosive gas into the inside when used in the hazardous area, and has the effect of significantly reducing the risk of explosion and fire when a spark occurs. have.

Claims (2)

An upper case and a lower case formed with a power cable connection hole are coupled to each other to have an explosion-proof housing structure, and a plurality of selection switches inside the upper and lower cases and an ammeter for measuring a current value of power applied from the outside by the selection switch. In the explosion-proof control switch box is formed, Form a transparent panel on the upper case to visually check the current value measured by the ammeter, An explosion-proof control switch box, characterized in that the transparent panel is formed integrally with the upper case. The method according to claim 1, Attach a bushing made of metal to the power cable connection hole of the lower case, An explosion-proof control switch box, characterized in that the bushing is formed integrally with the lower case.