5.1.2 Insulating Sleeves
1.Basic Structure and Function of Insulating Sleeves
(1)Basic structure
Insulating sleeves include impregnated and molded types.Impregnated rubber insulating sleeves have the same process with the insulating gloves,but the molded insulating sleeves are formed by a mold press type.
The insulating sleeve buckles and sleeves are shown in Fig.5-5 and 5-6.
Fig.5-5 Insulating Sleeve Buckles
Fig.5-6 Insulating Sleeves
(2)Basic function
Insulating sleeves for live working are used in contracted grade insulating gloves to protect the shoulder arm;the sleeve buckles are used with sleeves and require good electrical properties,high mechanical properties,and good insulation properties.
2.Classification and Technical Specifications of Insulating Sleeves
(1)Classification
①Insulating sleeves are divided into two types:straight and elbow,according to the shape.
②Insulating sleeves with special properties can be divided into five types:A,H,Z,S and C,which are resistant to acid,oil,ozone and low temperature.
③The sleeves are divided into 0,1,2 and 3 levels according to the pressure level.
(2)Technical specifications
①Thickness:Insulating sleeves shall be sufficiently flexible and flat,and the maximum thickness of the synthetic rubber must meet the requirements of Table 5-4.
Table 5-4 Maximum Thickness of Synthetic Rubber
②Insulating sleeves shall be seamlessly made,and the small holes left by the sleeves and the cuffs must be made of non-metallic reinforced edges,typically 8 mm in diameter.
③The inner and outer surfaces of the sleeves shall be even,smooth,regular,without small holes,cracks,local bulges,no inclusions of conductive foreign matter at the incision,no creases,irregular corrugations and cast marks.(https://www.daowen.com)
3.Inspection Items for Insulating Sleeves
Before use,insulating sleeves must be inspected,including visual inspection(visual inspection of the inner and outer surfaces of the cuff,requiring uniform surface),dimensional inspection,thickness inspection,process and molding inspection,marking inspection,ad packaging inspection.
4.Usage of Insulating Sleeves
(1)Before use,it is necessary to carry out appearance inspection.
(2)Connect the insulating sleeve and the insulation buckle securely.
(3)Avoid being scratched by sharp objects or sharp objects.
5.Precautions for Storage of Insulating Sleeves
(1)The insulating sleeves cannot be folded,for crease will cause the rubber to be oxidized and reduce the insulation performance.The storage of the insulating sleeves is shown in Fig.5-7.
Fig.5-7 Storage of Insulating Sleeves
(2)The sleeves should be stored in the correct size storage,placed flat,and a storage bag placed in a pair of cuffs.
(3)Insulating sleeves shall be packed by pieces.Attention shall be paid to prevent direct sunlight or being stored near artificial heat sources.In particular,it is necessary to avoid direct contact with sharp objects,which may result in punctures or scratches.
(4)It is not allowed to contact with oil,acid,alkali or other harmful substances,and be more than 1m away from the heat source.The storage environment temperature should be 10-21°C.
(5)In case that the sleeves are dirty,it is necessary to wash with soap and water,and apply talcum powder after thorough drying.In case that a mixture of tar and paint adheres to the gloves,it is necessary to wipe it off with suitable solvent.
(6)In case that the sleeve is wet during use or dried thoroughly after washing,the drying temperature shall not exceed 65°C.
6.Test Items for Insulating Sleeves
The conventional test contents of conventional insulating sleeves are as follows.
(1)Mechanical test.The mechanical test includes tensile strength and elongation test,mechanical puncture resistance test,and tensile permanent deformation test.
(2)Electrical withstand voltage test.Including type test,sampling test and factory routine test.The voltage duration for the type test and sampling test is 3min and that for the predelivery test is 1min.
(3)The preventive test of the insulating sleeve shall be conducted once every six months.