BS 4371-1991 Specification for fibrous gland packings《纤维质密封垫规范》.pdf

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1、BRITISH STANDARD BS 4371:1991 Specification for Fibrous gland packingsBS4371:1991 This British Standard, having been prepared under the directionof the Piping Systems Components Standards Policy Committee, was published underthe authority of the Standards Board and comes intoeffect on 28June1991 BSI

2、 12-1999 First published October 1968 Second edition June 1991 The following BSI references relate to the work on this standard: Committee reference PSE/2 Draft for comment 88/77248 DC ISBN 0 580 19621 6 Committees responsible for this British Standard The preparation of this British Standard was en

3、trusted by the Piping Systems Components Standards Policy Committee (PSE/-) to Technical Committee PSE/2, upon which the following bodies were represented: Asbestos Information Centre Ltd British Adhesives and Sealants Association British Compressed Gases Association British Gas plc British Pump Man

4、ufacturers Association British Railways Board Energy Industries Council Engineering Equipment and Materials Users Association Institution of Gas Engineers Institution of Water and Environmental Management Liquefied Petroleum Gas Industry Technical Association (UK) Water Services Association of Engla

5、nd and Wales Amendments issued since publication Amd. No. Date CommentsBS4371:1991 BSI 12-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Shape and cross section 2 3 Size 2 4 Packaging 2 5 Marking 2 6 Type A: Lubricated plaited cotton packing 2 7 Type B: Lubric

6、ated plaited bast fibre packing 3 8 Type C: Lubricated plaited or braided asbestos packing 3 9 Type E: Plaited or braided asbestos packing, metallic wire reinforced 4 10 Type H: Lubricated PTFE dispersion impregnated plaited or braided asbestos yarn packing 4 11 Type J: Lubricated, PTFE dispersion i

7、mpregnated plaited or braided aramid yarn packing 5 12 Type K: Lubricated, PTFE dispersion impregnated plaited or braided PTFE yarn packing 5 13 Type L: Lubricated, plaited or braided packing or graphited PTFE yarn 6 14 Type M: Loose fibre packing (non-asbestos) 6 Appendix A Methods of test 7 Append

8、ix B Information to be supplied by the purchaser 9 Table 1 Types of fibrous gland packing 1 Table 2 Cross sections and tolerances 2 Table 3 Materials for wire 4 Publication(s) referred to Inside back coverBS4371:1991 ii BSI 12-1999 Foreword This British Standard has been prepared under the direction

9、 of the Piping Systems Components Standards Policy Committee and supersedes BS4371:1968 which is withdrawn. Three types of packing (types D, F and G) that were in the original specification are now obsolete and, therefore, are omitted from this standard. (To avoid confusion, these three designations

10、 have not been reallocated in this standard.) Five additional types have been included to cover developments since the initial publication. Certain of the packings contain polytetrafluoroethylene (PTFE) which, when heated to elevated temperatures, may produce fumes which give unpleasant effects if i

11、nhaled. Care should be taken to avoid contaminating tobacco with PTFE. The method of designating density of yarns in this specification is in accordance with BS947. Fibrous gland packing may contain asbestos. The manufacture of all asbestos based products is covered by the requirements of the Contro

12、l of Asbestos at Work Regulations1987, introduced on1March1988. These set out comprehensive provisions covering work activities involving exposure to asbestos. Advice on how to comply with these regulations can be obtained from the manufacturers of the material, from the Asbestos Information Centre

13、Ltd., Derby Road, Widnes, Cheshire WH8 9ND from the local area office of the Health and Safety Executive or from the Environmental Health Department of the Local Authority. Particular note has to be taken of the Asbestos Products (Safety) Regulations1985, made under the Consumer Safety Act1978 and t

14、he Health and Safety at Work etc. Act1974, which sets out requirements for the labelling of all products containing asbestos. All the above legislation implements European Directives. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standard

15、s are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. In particular attention is drawn to the Control of Asbestos at Work Regulations 1987, and the Asbestos Products (Safety Regulations)1985 and the Health and S

16、afety at Work etc. Act 1974. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the am

17、endment table on the inside front cover.BS4371:1991 BSI 12-1999 1 1 Scope This British Standard specifies the description, materials, lubricants, size, mass, packaging and marking of nine types of fibrous gland packings. Tests are specified for the determination of lubricant content, size, mass and

18、ignition loss (seeAppendix A). NOTE 1This standard does not specify electrical cable gland packings. NOTE 2Table 1 gives guidance on the normal usage of the nine types of fibrous gland packings specified in this standard. The purchaser should state in his enquiry or order the type of packing (seeApp

19、endix B). NOTE 3The titles of the publications referred to in this standard are listed on the inside back cover. NOTE 4The information to be supplied by the purchaser at the time of enquiry and/or order is given inAppendix B. Table 1 Types of fibrous gland packing Designation General description Fur

20、ther description and application Type A Lubricated, plaited or braided cotton packing. Cotton packing with a mineral hydrocarbon lubricant. Temperature limit85 C. Typical duties: Centrifugal pumps, sludge pumps, water pumps. Type B Lubricated, plaited or braided bast fibre packing. Bast fibre packin

21、g with a percentage of tallow. Temperature limit 85 C. Typical duties: Reciprocating pumps, hydraulic equipment. Type C Lubricated, plaited or braided asbestos packing. Asbestos packing with a mineral oil content. Temperature limit300 C. Typical duties: Rotary and reciprocating shafts, steam, boiler

22、 feed pumps, process liquor pumps, caustic pumps, mild chemical duties, gas valves, condensate pumps, evaporators, compressed air valves. Type E Plaited or braided asbestos packing, metallic wire reinforced. Wire reinforced asbestos packing treated with a binder and, if required, further lubricated

23、with mica or graphite. Temperature limit510 C. Typical duties: Dry heat applications, boiler stop valves, (not suitable for acid or alkali service). Type H Lubricated, PTFE dispersion impregnated plaited or braided asbestos yarn packing. An asbestos packing impregnated with PTFE and a mineral oil lu

24、bricant. Temperature limit260 C. Typical duties: Rotary pumps. For general chemical service including alkalis and certain acids. Type J Lubricated, PTFE dispersion impregnated plaited or braided aramid yarn packing. An aramid yarn packing impregnated with PTFE and silicone oil lubricant. Temperature

25、 limit260 C. Typical duties: Rotary and reciprocating pumps, and valves, and suitable for service with many chemicals including weak acids and alkalis, solvents and abrasives. Type K Lubricated, PTFE dispersion impregnated plaited or braided PTFE yarn packing. A PTFE yarn packing impregnated with PT

26、FE dispersion and silicone oil lubricant. Temperature limit260 C. Typical duties: Service with highly corrosive chemicals on rotary pumps, reciprocating pumps and valves (except strong oxidizing agents and molten alkali metals). Type L Lubricated, plaited or braided packing of blended graphite and P

27、TFE yarn. A blended PTFE and graphite yarn packing with additional PTFE and silicone oil lubricant. Temperature limit260 C. Typical duties: Valves and rotary pumps handling a wide range of media (except strong oxidizing agents and molten alkali metals). Type M Loose fibre packing (non-asbestos). A l

28、oose (non-asbestos) fibre packing for caulking of stuffing boxes. Temperature limit450 C. Typical duties: Cocks and valves. NOTETypes D, F and G are obsolete. WARNING NOTE. Materials containing asbestos are subject to legislation that requires precautions to be taken when handling them to ensure tha

29、t they do not constitute a hazard to health (see foreword).BS4371:1991 2 BSI 12-1999 2 Shape and cross section 2.1 The packing shall be provided in length form unless requested as rings. 2.2 The packing shall have a square cross section. 3 Size The cross section size of the packing, when determined

30、in accordance with A.4, shall not vary from the nominal thickness in either thickness direction by more than the limits given inTable 2. Table 2 Cross sections and tolerances 4 Packaging All gland packings shall be despatched in sealed parcels and shall be protected against damage and ingress of dir

31、t in transit. 5 Marking Each parcel shall be clearly and legibly marked with the following information: a) the manufacturers name or other means of identification, b) the number of this British Standard followed by the type of packing, e.g. “BS 4371/type A”, 1) c) the cross section size and the leng

32、th of the gland packing or number of rings. NOTEWhere relevant, warning labels and safety instructions as required by any relevant legislation should be included (seeforeword). 6 Type A: Lubricated plaited cotton packing 6.1 Description The packing shall be plaited or braided. The cotton yarn shall

33、be uniformly impregnated prior to, or during, manufacture with either: a) lubricant and graphite, or b) lubricant and mica. NOTE 1The purchaser should state in his enquiry or order whether graphite or mica is to be used (seeAppendix B). NOTE 2The purchaser should state in his enquiry or order the di

34、mensions of the packing (seeAppendix B). 6.2 Yarn The yarn shall be spun from cotton having a minimum staple length of12mm. The single ply yarn shall not exceed475tex 2) . Straight ends in the centre and/or the corners shall be of the same grade as the yarn used in the rest of the packing and shall

35、not exceed30% of the mass of the packing for sizes10mm section and above and shall not exceed35% of the mass of the packing for sizes less than10mm section. 6.3 Lubricant The lubricant shall be either petroleum jelly, a mixture of petroleum oil and petroleum jelly, or a lime-base grease. The lubrica

36、nt content of the packing, when determined as described inA.2.4.1, shall be a minimum of40% and a maximum of50% by mass of the total mass of the packing. The graphite or mica content of the packing, as appropriate, when determined as described inA.2.4.2, shall be a minimum of5% and a maximum of15% b

37、y mass. 6.4 Mass The mass in grams per metre of packing, when determined as described inA.5, shall be not less than1.00S 2 , where S is the nominal cross section width of the packing inmm. Nominal section Tolerance mm mm k 9 0.5 9 to 18 1.0 18 to 38 1.5 38 to 60 2.0 60 to 75 3.0 75 5.0 1) Marking BS

38、4371 on or in relation to a product represents a manufacturers declaration of conformity, i.e. a claim by or on behalf of the manufacturer that the product meets the requirements of the standard. The accuracy of the claim is therefore solely the responsibility of the person making the claim. Such a

39、declaration is not to be confused with third party certification of conformity which may also be desirable. 2) 1 tex =10 6 Kg/m.BS4371:1991 BSI 12-1999 3 7 Type B: Lubricated plaited bast fibre packing 7.1 Description The packing shall be plaited or braided. The bast fibre yarn shall be uniformly im

40、pregnated prior to, or during, manufacture with either: a) lubricant and graphite, or b) lubricant and mica. NOTE 1The purchaser should state in his enquiry or order whether graphite or mica is to be used (seeAppendix B). NOTE 2The purchaser should state in his enquiry or order the dimensions of the

41、 packing (seeAppendix B). 7.2 Yarn The yarn shall be spun from bast fibre tow. The single ply yarn shall not exceed: Straight ends in the centre and/or the corners shall be of the same grade as the yarn used in the rest of the packing and shall not exceed30% of the mass of the packing for sizes10mm

42、section and above and shall not exceed35% of the mass of the packing for sizes less than10mm section. 7.3 Lubricant The lubricant of the packing shall consist of refined mutton tallow with a percentage of free acid (expressed as oleic acid) not exceeding2% by mass of the total mass of the packing at

43、 the time of manufacture, or a combination of such tallow and a mineral lubricant. The tallow content or combined tallow/mineral lubricant content of the packing, when determined as described inA.2.4.1, shall be a minimum of35% and a maximum of45% by mass of the total mass of the packing. The graphi

44、te or mica content of the packing, as appropriate, when determined as described inA.2.4.2, shall be a minimum of5% and a maximum of15% by mass of the total mass of the packing. 7.4 Mass The mass in grams per metre of packing, when determined as described inA.5, shall be not less than1.00S 2 , where

45、S is the nominal cross section width of the packing in millimetres. 8 Type C: Lubricated plaited or braided asbestos packing 8.1 Description The packing shall be plaited or braided. The asbestos fibre yarn shall be uniformly impregnated prior to, or during, manufacture with either: a) mineral lubric

46、ating oil and graphite, or b) mineral lubricating oil and mica. NOTE 1The purchaser should state in his enquiry or order whether graphite or mica is to be used (seeAppendix B). NOTE 2The purchaser should state in his enquiry or order the dimensions of the packing (seeAppendix B). WARNING. Materials

47、containing asbestos are subject to legislation that requires precautions to be taken when handling them to ensure that they do not constitute a hazard to health (see foreword). 8.2 Yarn The yarn shall be spun from long, white chrysotile asbestos fibre, having an abestos content of not less than85% b

48、y mass. The single ply yarn excluding that in the central core shall not exceed: Straight ends in the centre and/or the corners shall be of the same grade as the yarn used in the rest of the packing. The straight ends used in the centre and/or the corners shall not exceed30% of the mass of the packi

49、ng for sizes10mm section and above and shall not exceed35% of the mass of the packing for sizes less than10mm section. 8.3 Lubricant The lubricant shall consist of a mineral hydrocarbon oil with the following characteristics: The mineral hydrocarbon oil shall contain not more than25% additives to improve oil performance. The mineral oil content of the packing, when determined as described inA.2.4.1, shall be a minimum of23% and a maximum of33% by mass of the total mass of the packing. The graphite or mica content of the packing, as appropriate, w