1. INTENDED USE AND SCOPE OF APPLICATION
SHORVA type explosion-proof boxes are stationary devices which are intended for arrangement of terminal blocks, control, signaling devices and other electrotechnical components for installation in hazardous areas.1
Scope of application – mines and pits hazardous with gas (methane) or coal dust, outdoor and indoor hazardous areas, as per explosion protection marking, GOST 30852.13-2002 (IEC 60079-14:1996), and areas with presence of combustible dust, as per GOST IEC 61241-3-2011, dangerous production facilities of I, II, III, IV hazard class supervised by Rostechnadzor and national technical supervision bodies of the CU and CIS countries.
SHORVA explosion-proof boxes with a window are applied for control and measuring equipment arrangement, as well as for any equipment for visual control (including monitors).
All cable glands, as well as installed components (terminal blocks, circuit breakers, etc.) are used as per the rules specified in the description of CCFE boxes.
2. DESCRIPTION OF THE PRODUCT DESIGN AND MEANS OF EXPLOSION PROTECTION
SHORVA explosion-proof boxes consist of an enclosure and a cover manufactured from modified corrosion-resistant aluminum-silicon alloy resistant to salt spray and other chemical substances including hydrogen sulfide and hydrochloric acid vapors, salty and acidimic mine waters, frictionally intrinsically safe. Upon request, the boxes can be manufactured from stainless steel grade 03Х17Н13М2 as per GOST 5632-2014 (AISI 316L), resistant to alkali and drops of hydrochloric and sulfuric acid.
Composition of aluminum-silicon alloy GALSi13 grade “KSi13”: Cu 0.1%, Fe 0.4%, Si 12-13,5%, Mg 0.1%, Mn 0.4%, Zn 0.1%, Ti 0.15%, Ni 0.1%, impurities: 0.3%, others - Al.
Composition of stainless steel grade 03Х17Н13М2 as per GOST 5632-2014 (AISI 316L): C 0.035%, Cr 16.0-18.0%, Ni 10.0-15.0, Mo 2.0- 3.0%, P 0.04%, S 0.03%, Mn 2%, Si 0.75% (often used at chemical plants and in marine equipment as it is highly strong, resistant to high temperatures and corrosion).
Cable glands are arranged on the side surfaces of the enclosure. Control boxes have inner and outer ground clamps.2
The type of explosion protection “flameproof enclosure” is reached by design features of the enclosures with parameters of flameproof joints conforming to the requirements of GOST 30852.1-2002 (IEC 60079-1-1998). Flameproof enclosures withstand explosion pressure and make its distribution to hazardous atmosphere impossible, which is confirmed by test results.
Marking applied to terminal boxes shall contain the following information:
– trademark of the manufacturing plant;
– type of the product;
– serial number and the year of production;
– explosion protection marking - 1ExdIICT4/T5/Т6 or 1Exd[ia]CT5/T6 or DIP А21 TA T4/T5/T6/70°C;
– warning sign “De-energize before opening”;
– ambient temperature range;
and other information which shall be indicated in the marking if this is required by technical documentation.
4. LIST OF REGULATORY DOCUMENTS THE PRODUCTS COMPLY WITH
GOST 12.2.007.0-75. Occupation safety standards system. Electrical equipment. General safety requirements.
GOST 30852.0-2002 (IEC 60079-0:1998). Explosion-proof electrical apparatus. Part 0. General requirements.
GOST 30852.1-2002 (IEC 60079-1:1998). Explosion-proof electrical apparatus. Part 1. "Flameproof joint" type of explosion protection.
GOST R 51330.13-2002. Explosion-proof electrical apparatus. Part 14. Electrical installations in explosive gas atmospheres (other than mines).
Ch. 7.3 Electrical Installations Code, Ch. 7.4 Electrical Installations Code,
1SHORVA series explosion-proof boxes are multifunctional and can be used for solving a wide range of tasks, including their application as terminal boxes in general industrial version or for installation in a hazardous area. Peculiarities of the design of these boxes allow using them for various purposes: as terminal boxes, boxes for power clamps, boxes for arrangement of various equipment inside, as enclosures and control cabinets for potentially hazardous areas and conditions with aggressive atmosphere. It is necessary to point out the possibility of application of these products by integrated equipment manufacturers, where superior quality of mechanical processing of aluminum is put to the forefront.
2Outer and inner ground clamps are manufactured from stainless steel and can be connected to the mounting rail for terminals, mounting plate or a grounding bar. As aluminum is an excellent conductor, grounding for cable glands is provided by a contact with enclosure wall without necessity of taking additional measures for ensuring continuity of grounding circuit.
3SHORVA series boxes are approved for application in hazardous areas and are supplied with certificates (depending on the project): ATEX, TR CU – zone 1 and zone 2. CCA series boxes can be supplied in different versions: with installation of terminals for various currents, with Ex-components as per customer’s specification or empty as an Ex-component required in the customer’s equipment during certification.
Application of modified corrosion-resistant aluminum-silicon alloy resistant to salt spray and other chemical substances including hydrogen sulfide and hydrochloric acid vapors, frictionally intrinsically safe, ensures relatively light weight of the enclosures which significantly simplifies installation on the site. This is especially noticeable on small or medium-sized enclosures.
Various combinations of cable glands are possible. Thickness of enclosure walls is sufficient for drilling threaded holes in enclosure walls for connection of cable glands of various types.
Exd enclosures of the majority of manufacturers are intended for temperatures not lower than -20°C/-25°C, further lowering of the temperature requires installation of internal nondisconnecting heater, which makes the design of the product more complex and increases its cost (enlargement of enclosure size for the arrangement of a heater and a thermostat, provision of uninterruptible power supply and application of external protective safety switch). SHORVA enclosures manufactured by "ZAVOD GORELTEX" Co. Ltd. (previously "CORTEM-GORELTEX" Co. Ltd.) are designed and tested in conditions to -60 °C. This is especially important for terminal boxes.
Conformity of enclosures manufactured by "ZAVOD GORELTEX" Co. Ltd. (previously "CORTEM-GORELTEX" Co. Ltd.) to the requirements of TR CU regarding means that ensure the level and type of explosion protection. Features of Russian norms which are different from ATEX and IEC standards are taken into account when manufacturing.
"ZAVOD GORELTEX" Co. Ltd. (previously "CORTEM-GORELTEX" Co. Ltd.) has a wide range of enclosures for arrangement of different equipment considering convenience of installation. It is possible to install modular circuit breakers, contactors as well as buttons and signal lamps on the cover of enclosures.
Additional support of the cover on SHORVA enclosure by means of hinges significantly simplifies installation.
Control elements manufactured by "ZAVOD GORELTEX" Co. Ltd. (previously "CORTEM-GORELTEX" Co. Ltd.) are small-sized, hence increasing of the enclosure depth for their arrangement is not necessary.
The cover of the increased diameter on SHORVA enclosures provides more convenient access to internal components.
Modified corrosion-resistant aluminum-silicon alloy has low copper content (less than 0,1%) and iron (less than 0,4%), which ensures its resistance to aggressive exposure to sea water and increases its anti-corrosion properties, as the alloy has a special form of material structure, which was reached in the process of enclosure manufacturing. The alloy is characterized by low contents of magnesium which improves anti-frictional properties of the enclosure. These advantages allow using Goreltex enclosures made from modified corrosion-resistant aluminum-silicon alloy instead of stainless steel enclosures.
Technology implemented during production of enclosures by "ZAVOD GORELTEX" Co. Ltd. (previously "CORTEM-GORELTEX" Co. Ltd.) prevents formation of cracks in the enclosure, hence the additional processing of internal surface of the enclosure is not required. This enables to increase the value of heat dissipated power of the enclosure (painting of the internal surface significantly reduces thermal conductivity of enclosure walls which can lead to overheating and malfunction of electrotechnical components). Enclosures manufacture by "ZAVOD GORELTEX" Co. Ltd. (previously "CORTEM-GORELTEX" Co. Ltd.) can be operated for more than 30 years.
Nameplate with the name and a serial number is made from an aluminum plate and has a specially designated installation area, which conforms to TR CU norms.
The certificate covers not only the enclosure but also entire assembly when control cabinets are ordered. Finished product is delivered to the customer. "ZAVOD GORELTEX" Co. Ltd. (previously "CORTEM-GORELTEX" Co. Ltd.) installs all required Ex-components according to the customer’s specification.
Engineering support. "ZAVOD GORELTEX" Co. Ltd. (previously "CORTEM-GORELTEX" Co. Ltd.) helps to select an enclosure in accordance with the requirements of the customer and provides AutoCad drawings.