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Technical requirements and operation methods for explosion-proof isolation and sealing
Release time:
2024/07/04
Electrical circuits in Zone 1, Zone 2 and Zone 10 must be isolated and sealed. The purpose of the isolation seal is to cut off the explosive gas or flame isolation to prevent it from spreading to other parts through the tube, which shall meet the following requirements:
1. The following parts of steel pipe wiring must be isolated and sealed:
(a) Before the conductor is introduced into the joint parts (such as inlet and outlet boxes) of electrical equipment enclosures equipped with switches, air circuit breakers, fuses, relays, resistors or other electrical equipment enclosures that may generate arcs, sparks or dangerous high temperatures, if there is no isolation seal in the joint parts of the electrical equipment itself, the isolation seal box must be installed at a distance of not more than 45cm from the inlet and outlet equipment enclosures and as close to the electrical equipment as close as possible;
(B) Steel pipes with diameter of 50mm and above are within 45cm from the junction box with joints and taps introduced;
(c) Pipelines with diameter of steel pipe of 50mm and above shall be 15m away from each other;
(d), adjacent Zone 1, Zone 2 or Zone 10 explosion hazard environment; Zone 1, Zone 2, Zone 10 and adjacent other hazardous environment or non-hazardous environment.
The isolation seal box shall be located as close as possible to the partition wall. No pipe joints, junction boxes or any other connections are permitted between the wall and the isolation seal.
2. Isolation and sealing may not be done under the following conditions:
(a) The manufacturer of the equipment itself has been equipped with isolation and sealing devices;
(B) For pipelines passing through Zones 1, 2 and 10, where there are no unions, joints, junction boxes or fittings on the entire pipeline, and where there are no fittings within 300mm outside the boundary of each of the above hazardous areas, if the terminal of this complete pipeline is located in a non-hazardous environment, no isolation seal is required. (The steel pipe cannot be connected by welding).
Technical requirements for isolation and sealing
1. The isolation and sealing box shall be suitable for explosion-proof grade requirements of explosive hazardous environment.
2. The isolation and sealing box shall not be used as the connection or distribution of wires, nor shall other accessories with joints or taps be filled with glue.
3. The vertical type, horizontal type or general type isolation sealing box shall be selected according to the actual position of the pipeline. Where condensate may be introduced, the isolated sealed box of drainage type should be selected.
Operating method of isolation seal
1. Install the explosion-proof isolation seal box correctly and reliably in the specified position according to the design and specification requirements. The threaded engagement between the box and the wire pipe shall be tight, and the number of buckles shall be DN25mm and not less than 5 buckles below; No less than 6 buckles above DN32mm. Do a good job of anti-corrosion treatment. The inner wall of the box shall be cleaned and there shall be no oil, rust or other impurities to avoid affecting the performance.
2. Wire threading:Do not damage the insulation of the wire sheath during threading, and check whether the wire type and specification meet the design.
3. Filling and sealing material:
(1) Open the operation port cover of the explosion-proof isolation seal box, and separate the wires with a spatula.
(2) Fill the plugging material. Use a spatula to sequentially fill the sealing fibers around the wire. First fill the back of the wire, then plug between the wires, and finally fill the front of the wire. The sealing fiber must be pressed in tightlyExplosion-proof isolation seal boxThe neck of the plug. Fibers are used as a bottom layer or barrier for the filler layer to prevent the sealing compound from flowing out. Only the lower part of the longitudinal box shall be blocked, and both sides of the transverse box shall be blocked. The effective thickness of the filling layer must be greater than the inner diameter of the steel pipe.
(3) Tighten the operating cover after filling the plugging material. The injection port of the transverse type should face upward. The drainage type only needs the baffle plate, and it is not necessary to screw on the operating cover.
(4) Open the injection port and make preparations before pouring.
4. Blending powder sealing filler:
(1) Clean the container and pour clean water according to the dosage specified in the product specification of the manufacturer.
(2), gradually evenly pour the right amount of powder filler, so that all the filler in the water soaked.
(3) After the powder sealing filler is completely saturated with water, vibrate the container slightly, and then slowly stir for 1~2min at a speed of 60 revolutions per minute with a stirring rod to make it all evenly mixed.
5. Pouring and sealing packing
(1) Inject the mixed sealing packing into the box while stirring. Inject about 80% of the dosage, beat the explosion-proof isolation sealing box to make the sealing packing uniform, and then fill it up. During the pouring process, if the sealing filler starts to harden, it cannot be forcibly stirred by adding water, and the pouring shall be stopped immediately, and the remaining material cannot be reused. After injection, the filler shall remain unmoved until it has hardened completely.
(2) The normal temperature initial setting time of the sealing packing is about 40min, and the final setting time is about 1hr. After confirming that the powder sealing packing is fully hardened, tighten the injection bolts. For drainage type, screw cap shall be tightened.
(3) The filling height or length of the sealing filler shall be strictly implemented according to the requirements, and shall not be less than the pipe diameter and shall not be less than 20mm.
The above items should be operated by trained personnel, and the inspectors should cooperate at any time to ensure the quality and make records.
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