Explosion analysis of changes in the standard bridge cranes

National Development and Reform Commission on 27 November 2006 issued by China Machinery Industry Standard JB/T5897--2006 "explosion-proof crane" (hereinafter referred to as 2006 version of the standard) was May 1, 2007 officially started to implement. This standard replaces the JB/T5897--1991 "explosion-proof crane" (hereinafter referred to as 1991 version of the standard). 2006 version of the standard compared with the 1991 version of the standard has changed a lot, mainly in the following aspects.

1 adds new content
In the 2006 version of the standard compared with the 1991 version of the standard adds two chapters, namely Chapter 3, "Terms and Definitions" and Chapter 1O "use and maintenance."
Increase in new Chapter 3, "Terms and definitions" including explosive gas atmospheres and flammable "raw dust atmospheres - Terms and definitions into two categories. Which by the GB3836.1-200O "Electrical apparatus for explosive gas atmospheres - Part 1: General requirements" and GB3836.14-2000 "Electrical apparatus for explosive gas atmospheres - Part 14: Classification of hazardous areas" identified in the terms used in explosive gas atmospheres and the definition of "explosive gas atmospheres" and 8.
By the GB12476.1-200O "combustible dust electrical equipment - Part 1: Use protective enclosures and surface temperature limitation of electrical equipment - Part 1: Electrical equipment technical requirements" identified in flammable dust atmospheres - Terms and definitions have "combustible dust" etc. 12. These terms and definitions to determine the explosion  overhead bridge crane  production and testing has a very important significance.
Increase in new Chapter 10, "use and maintenance" for the first explosion-proof  bridge crane  users were asked the corresponding requirements. Are:
(A) the provisions of the crane rail installation should comply with GB/T10183 requirements, and grounding resistance is not greater than 4Ω.
(2) provides for the crane wire rope during use them to pay attention to maintenance and timely replacement.
(3) provides for the use of the crane unit according to standards established a sound management system at all times to ensure that the crane is in good running condition.

Two clear proof crane classification
In the 2006 version of the standard Chapter 4, "classification and grouping" for the first time clearly states that "a crane with its electrical equipment used to classify and group environment." 2006 version of the standard provisions of the crane based
GB3836.1-2000 requirements, according to explosive atmospheres are divided into class I and class II electrical equipment; GB12476.1-2000 based on the provisions of combustible dust electrical equipment only in Class I, the corresponding crane is divided into three classes.
Class I: Coal crane;
Class II: In addition to coal mines and other explosive gas atmospheres crane;
Dust categories: combustible dust cranes.
Where explosive gas atmospheres Class Ⅱ Crane flameproof "d" and intrinsically safe "i", GB3836.1-2000 Appendix B of the characteristics of explosive gases by divided into IIA, IIB, IIC
Class cranes. But IIC environments containing acetylene should be stated in the contract.
Combustible "raw dust with a crane on the ability of electrical equipment Dust divided into A, B type two types, of which type A type B is based on the increase of the" thermal cycle test "requirement, expressed respectively DIPA and DIPB .

3 Material changes
(1) In the 2006 version of the standard crane metal structure welded structure important material from the 1991 version of the standard required in a B or 16Mn Q235 changed to killed steel.
(2) In the 2006 version of the standard crane cable pulley wheel and limit switch on the touch wheel from the 1991 version of the standard material requirements of copper to brass or bronze surface resistance of less than 1GΩ engineering plastics.
(3) In the 2006 version of the standard crane buffers required by the 1991 version of the standard material of the surface resistance of less than 1GΩ rubber to the surface resistance of less than 1GΩ rubber or polyurethane.

4 Technical data changes
(1) In the 2006 version of the standard deviation from the helical groove rope hoist drum minimum angle required by the 1991 version of the standard 2. To 3. .
(2) In the 2006 version of the standard crane lifting speed quickly by the 1991 version of the standard in the 2 ~ 4m/min to 2 ~ 8m/mino
(3) In the 2006 version of the standard speed of the crane rope involved in the 1991 version of the standard to the maximum 16m/min max 28m/min.
(4) In the 2006 version of the standard crane trolley travel speed by the 1991 version of the standard to the maximum 10m/min max 25m/min, but IIC maximum of 10m/min.
(5) In the 2006 version of the standard crane walking speed by the 1991 version of the standard, the maximum 16m/min, IIC maximum of lOm / min to max 25m/min, but IIC maximum of 16m/min.

5 model representation has changed
In the 2006 version of the standard crane model representation by the 1991 version of the standard of proof required in overhead crane Code QB + nominal weight + span + crane working level, to crane Code QB + rated lifting capacity crane span + Work + level + proof mark, thus more prominent crane proof mark.