Brief Discussion on the Technical Requirements of Flameproof Joint of Flameproof Electrical Equipment

Nanyang Explosion-proof Group Co., Ltd. 2 Flameproof Joint Technical Requirements Flameproof electrical equipment refers to the electrical equipment with flameproof enclosures. The explosion-proof symbol is d. The flameproof enclosure is capable of withstanding the explosion pressure inside, and can prevent the explosion flame from Explosion-proof enclosure that spreads around the environment. Flameproof electrical equipment has good flameproof and explosion-resistant properties and is widely used in explosive environmental workplaces such as coal mines.

The explosion-proof enclosure consists of many parts, and the connection gap between the parts will become the route through which the explosive products in the enclosure pass and ignite the explosive gas mixture around. In order to prevent the internal explosion from propagating to the explosive gas mixture surrounding the housing, the mating parts of these parts are called flameproof joints, and the engagement gap is called the flameproof joint clearance.

The flameproof effect of the flameproof shell is to use the flange clearance of the shell to achieve flameproof. Flange clearance can play a role in flameproofing. The larger the flange clearance, the more explosive energy generated through the gap, the stronger the transmission performance, and the worse the flameproof performance. On the contrary, the smaller the flange clearance, the weaker the explosiveness and the better the flameproof performance.

The length of the flanged explosion-proof surface is also closely related to the flameproofness of the flange clearance. The longer the flameproof surface is, the less likely it is to transmit explosives, and the shorter the flameproof surface, the greater the possibility of propagation. In order to make the flameproof enclosure have the best flameproof property, people carried out experimental research on the size and explosion-proof performance of the flange gap of the flameproof enclosure. The test shows that the maximum non-detonation gap is the maximum test safety clearance. Studies have shown that the factors affecting the maximum test safety clearance are: (1) the concentration of the explosive mixture; the length of the flameproof flange and the surface roughness; (3) the volume of the flameproof enclosure; (4) the initial pressure of the explosion mixture , temperature and humidity; (5) the distance from the ignition source to the inner edge of the explosion-proof gap; (6) the flow state of the explosive mixture and many other factors. The following is a brief discussion of the technical requirements for the design of flameproof joints.

2.1 General requirements to go to 1 joint Lrrm I type outside the first PR of the S and S small heavy and big "with the outside of the first volume with P (c:> paired into a large joint in addition to the plane joint and only joint and iron Plunger shafts of longitudinal and plain bearings °1) In addition to the numerical values ​​shown in this table, the values ​​in Table 2-4 can be used for external filling of mills.

2) Thousands of hidden materials, affiliates, and annihilations between them.

040. The external charge volume does not exceed 5800 cW. It is only suitable for 1000-plane contact surface. And there are no moments of ignorance.

4> The small width of the flame-proof light-shielding surface of a large-scaled table, such as the straight drill of the Li-Lian vertical rod fU oil. The width of the joint surface is not less than one thousand inches of vertical bar or straight bar.

However, it is not necessary to use a large scale of 25mm 5, such as the small width of the erroneous combination of the erroneous dictates of the erroneously defined sequels of the 。 筏. According to the T race, with a sliding bearing compartment: the length of the flame through the bearing cover 矜 length, not less than 25mmH. Sleeveless sleeve sleeve aft: when the steam sleeve direct duty 25rwnH. into a small 25mm. Li uses the reed-type bearing or bearing-type bearing in the pit-type electric power supply of the Yu-you-yo bearing. a. Sets the unilateral distance between Hf and the unilateral disjoint displacement of the larger-than-benefit-allowed part. No matter how the sparks are played (such as the British W) 喵 改 改 改 改 改 改 - - 承 - 钤 钤 功 功 功 功 功Slide bearings are permitted for cylindrical metal parts (for example bushings with a metal flameproof enclosure wall with a volume of not more than 2000 cm3). If the design structure meets the following requirements, the joint width can be shortened to 5 mm: no interference fit In order to prevent parts from undergoing displacement during the type test of Clause 15 of GB3836.2, the structure can meet the requirements of the impact test in GB3836.1 in the most unfavorable interference fit tolerance; the diameter of the interference fit part must not exceed 60mm. Bonding jaw width / tLmm100 and outer bearing capacity with large clearance w 400.40 loose rod and shaft 40040 plain bearing journal >> 500.500.50 Foil bearing shaft> 7500.7500.7501> In addition to the teaching value of this table. The values ​​given in Tables B and C can be measured in thousands of A-series, 2-in. In addition to the foot 棺 S 筏茇 筏茇 筏茇 对 筏茇 对 L L L L 9.5 9.5 9.5 9.5 9.5 . . . . 0. However, if there is a conical surface on the joints, the width of the joint and the gap perpendicular to the surface of the joint should conform to the corresponding dimensions specified in Table 4 of Table 1. The gap between the entire conical parts should be uniform. For C electrical equipment enclosures, the taper must not exceed 5°.

The surface roughness R of the flameproof surface shall not be less than 6.3 microns. Except for the quick opening of the door or the cover, no intentional gap shall exist between the plane joints. If there is a gap between the joints, no matter where Table 1 shows the corresponding maximum values ​​specified in Table 4.

For Class I electrical equipment, it should be possible to check, directly or indirectly, the clearances of the plane joints of the doors or lids that are frequently opened.

Flameproof joints are available in flat, nosing, and threaded configurations. The cooperation of the joystick and the shaft is a cylindrical structure, which is respectively applied to the joint of the shell and the shell cover, the joint of the shell and the joystick, the joint of the motor shaft extension and the end cap, and the introduction of the cable or the wire. The junction with the housing and the junction between the meter and display window and the housing.

The joint width j of the joint of the spigot joint and the joint surface of the external replenishment volume KcnO form the joint between the 0 plane and the joint surface Xt 姊 degree 和 and the shaft 4> the rotation axis of the rotative bearing °> In addition to the values ​​given in this table outer. The values ​​in Table 4 can be used to charge thousands of B -> thousands of candles, sleeves, and 钤 axes. In the meantime, it means the big direct service.

Thousands of L, except 0.040im. outside the first volume does not exceed 5800cW only for the use of thousands of flat joints. For the millenium, he joints without volume HI.> According to Table 1笫'> Article Saido -> According to Table 1笫 "Secure game--) According to Table 1笫 K. Competition requirements - When determining the width of the joint of the mouth, should be The following conditions apply: When both the cylindrical part and the planar part are counted, the following additional conditions shall apply (see): When considering only the cylindrical part (see ), the flat part shall meet the following requirements: For Class I, A and B, The plane portion does not have to meet the clearance requirement; for C, the clearance of the plane portion should not exceed the maximum clearance specified in Table 4 for the cylindrical portion.

If spacers (see ) are installed on the flat part, the clearance of the flat part should be measured after compressing the liner. The minimum width of the joint portion of the cylindrical portion should be maintained before and after compressing the liner. However, if the C electrical equipment uses a metal or metal-clad compressible liner (see), then the gap between each surface of the planar portion and the seal liner should be measured after the liner is compressed.

For C equipment containing explosive atmospheres of acetylene, only planar surfaces are allowed to comply with the conditions of Note 2 of Table 4.

Holes or screw holes in the mating surface When the holes are outside the housing, the distance between each hole and the inside of the housing should be measured; when the holes are inside the housing, the distance between each hole and the outside of the housing should be measured distance. (See, 7, 8) When f and the gap in the cylindrical portion is not greater than 0 for Class I and A. Table 4C Foreign Minor M Minor S Smallness and Big 0 Joint Width and External First Volume Wcm) UN General Assembly to explain the plane junction joint surface (scarred joint surface (囝2> 12.5 矣 B 40 B "circular joint and escapement or axial n foil bearing press 抟 motor bearing 益 益 轻 轻 轻 轻 轻The surface 5 strokes 25 strokes is the sum of the width a of the cylindrical portion and the width b of the flat portion (see); if the above conditions are not satisfied, the distance is only the width of the flat portion b. The minimum engagement of the A and B housings, the thread engagement surface The number is 5. When the volume is greater than 100cm3, the minimum meshing axial length is 8mm;When the volume is not greater than 100cm3, the minimum axial meshing length is 5mm.(2) For the C shell, the threaded joint surface should meet the requirements of Table 5. .

2.4 Lining and O-Rings (1) If liners of compressible materials are used (eg IP protection against moisture, dust intrusion or liquid penetration), the liner should only be used as an auxiliary to the flameproof joint. Pieces. However, the effective parameters of the flameproof joint surface that cannot be included in the flameproof joint surface meet the requirements in Table 1 of Table 1. This requirement does not apply to wire and cable lead-in devices and sealing gaskets for transparent parts of lamps.

(2) If the liner is a metal or metal clad ISO-compliant compressible, non-combustible material, the liner can be fitted with a mating surface of the insulating sleeve and the transparent member.

2.5 Adhesive bonding surface 3 Concluding remarks When adhesive or sealing materials are used, the strength of the designed housing must not depend on the adhesive strength of the adhesive material or the sealing material.

The shortest path from the inside to the outside of the flameproof enclosure of volume V is through the adhesive bonding surface; the enclosure of the explosion-proof electrical equipment can ensure that the internal explosive gas mixture will not ignite the surrounding explosive gas mixture after explosion. It is safe and can be used for Zone 1 and Zone 2 explosive gas hazardous environments. The gap between the flameproof surfaces can play the role of flameproof. If the design of the flameproof surface does not meet the requirements of the standard, the electrical equipment will not achieve the explosion-proof effect. Therefore, we must strictly follow the national explosion-proof standards when designing and manufacturing flameproof electrical equipment.

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