+ Submit your article here

Types of Explosion Protection Equipment

10/8/2013 4:27:38 PM | by Anonymous

Explosion Protection Equipment

Explosion is a sudden destructive shattering reaction involving a rapid chemical, physical oxidation reaction or decay generating an increase in pressure or temperature or both simultaneously. The most familiar violent expansions are flammable gases, dusts or vapors with oxygen contained in the air.

 

Explosion protection equipment was introduced into the households and industry, immediately after the occurrence of coal dusts in mining and methane prompted the development of the basics of electrical explosion protection. They were so convincing that the intensive work was carried out to find a way that can reliably prevent contact between an explosive atmosphere and ignition sources originated from the use of electrical equipment to prevent explosion.

 

They are installed at locations specifically designed and tested to ensure that these equipments do not initiate an explosion due to the arcing contacts or high surface temperature of equipment. An example would be a household light switch that may emit a small and harmless visible spark when switching. But in an ordinary atmosphere this arc is of no concern and if a flammable vapor is present, the arc might start an explosion. Some types of explosion protection equipment that are used in the households and industry are encapsulation, non-incendive component, encapsulation device and non-sparking device.

 

Encapsulation Device

They are parts that could ignite an explosive atmosphere by the means of heat or sparks that are potted to prevent the ignition of the explosive atmosphere. This can be achieved by encapsulating the components in a compound resistant to physical such as thermal, electrical, mechanical and chemical influences. They are designed to be resistant to various influences, low water absorption and casting compound. This must be of the stipulated thickness all round and breakdown strength but the cavities are only permitted to a limited extent. This equipment may include cavities which are fully enclosed that are similar to the encapsulation type of protection such as in a casting compound so that the outer atmosphere is prevented. However, it is impossible to open the equipment during the normal operation or internal free volume that is less than or equal to 100cm. Besides, the external connections, cables and terminals must be available; cast seal must permit to permanent operating temperature that is less than 10 K as compared to the maximum operating temperature.

 

Non-Incendive Components

They are the variant of the ex and type of protection with contacts which can close and open a circuit box. This will enable to trigger an explosion where the contact mechanism or the enclosure into the contacts that are enclosed and designed in such a way that the ignition of a mixture of the subgroup IIA, IIB, IIC in the surrounding environment and is prevented as long as the operating conditions apply. The explosion protection equipment is limited to AC 254 V and 16 A, free internal volume that is less than or equal to 20cm, the encapsulation must permit to a permanent temperature of more than or equal to 10 K and has a combination of the parts that is tightly sealed. This component is to have contacts for making and breaking an incendive circuit as well as the contacting mechanism that is constructed so that the component is incapable of igniting the specified flammable gas-air or vapor-air mixture. However, the housing of a non-incendive component is not intended to exclude containing of an explosion or flammable atmosphere.

 

Non-Sparking Device

This explosion protection equipment is constructed and ensures reliable prevention of unacceptably high sparks and temperature or electrical arcs. Both are internal and external parts of the electrical equipment whose normal operation does not involve unacceptably high temperature that sparks or arcing. However, special requirements must be fulfilled by certain types of equipment as well as the air and creep age gaps are specified.

 

Enclosed-break Device

This is a switchgear which can open and close a circuit potentially and able to trigger an explosion where the enclosure will withstand an internal explosion of a mixture of subgroup such as IIB, IIA and IIC without transferring the explosion to the external mixture in the surrounding area and being damaged. They are designed in free interval volume less than or equal to 20cm and they must permit a permanent temperature of more than 10K as compared to the maximum operating temperature.

 

Pressurized Enclosures

This explosion protection equipment is the enclosure of the electrical equipment and is prevented by maintaining an ignition shield gas such as air or a different suitable gas. An advantage of this equipment is that the overpressure is maintained with and without constant flushing of the protective gas. The pressurized enclosures are designed to strengthen the enclosure of the surrounding and flushed enclosure must withstand 1.5 times of the overpressure experience during the normal operation. However, if the flushing gas overpressure or gas flow fails the equipment will shut down.

Are you sourcing for a product or service?

Do you need a quotation?