1、BRITISH STANDARD BS7335-2:1991Installation of monolithic refractoriesPart2: Code of practice for installation by gunningBS7335-2:1991This BritishStandard, having been prepared under the directionof the Refractory Products Standards Policy Committee, was published underthe authority of the BoardofBSI
2、 and comesintoeffecton 28February1991 BSI 01-2000The following BSI references relate to the work on this standard:Committee reference RPM/8Draft for comment89/40140DCISBN 0 580 18709 8Committees responsible for this BritishStandardThe preparation of this BritishStandard was entrusted by the Refracto
3、ry Products Standards Policy Committee (RPM/-) to Technical CommitteeRPM/8, upon which the following bodies were represented:British Cement AssociationBritish Ceramic Research Ltd.British Metallurgical Plant Constructors AssociationBritish Steel IndustryCoke Oven Managers AssociationCombustion Engin
4、eering AssociationDepartment of Trade and IndustryEnergy Industries CouncilEngineering Equipment and Materials Users AssociationInstitute of Refractories EngineersMETCONNational Federation of Master Steeplejacks and Lightning Conductor EngineersRefractories Association of Great BritainRefractory Con
5、tractors AssociationAmendments issued since publicationAmd. No. Date CommentsBS7335-2:1991 BSI 01-2000 iContentsPageCommittees responsible Inside front coverForeword ii1 Scope 12 Definitions 13 Planning 14 Personnel 25 Gunning materials 26 Water supply 37 Equipment 38 Preparation for gunning 79 Inst
6、allation 910 Replacement of unsatisfactory panels 1311 Curing 1412 Drying out and initial firing 1513 Quality of the lining 15Figure 1 Operation of feed-wheel gun 17Figure 2 Detail of lower chamber of feed-wheel gun 19Figure 3 Detail of barrel of rotating barrel gun 20Figure 4 Rotating bowl gun 21Fi
7、gure 5 Components of typical dry mix gunning nozzle 21Figure 6 Test panel box 22Table 1 Air pressure guide 11Table 2 Troubleshooting guide 14Publication(s) referred to Inside back coverBS7335-2:1991ii BSI 01-2000ForewordThis Part of BS7335 was prepared under the direction of the Refractory Products
8、Standards Policy Committee.The purpose of this code of practice is to advise on good or recommended practices before, during and after installation. Nothing in the code should be taken as a specification for either the materials or their installation.Assessed capability. Users of this BritishStandar
9、d are advised to consider the desirability of assessment and registration of a suppliers quality systems against the appropriate Part of BS5750 by a third party certification body.A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards ar
10、e responsible for their correct application.Compliance with a British Standard does not of itself confer immunity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, pagesi andii, pages1 to22, an inside back cover and a back cover.This standard has be
11、en updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS7335-2:1991 BSI 01-2000 11 ScopeThis Part of BS7335 describes good practice for working procedures in the installation of refractory linings by gunning
12、techniques. The code is specifically concerned with the “dry” gunning of initial or replacement linings, using refractory materials bonded by calcium aluminate cement. Major repairs, involving the removal of old panels of the lining back to the shell, are also covered. Recommendations for ensuring t
13、hat compliance with the agreed design has been achieved are included, where appropriate.Wet gunning and gunning repairs to hot linings are excluded. The gunning of linings for steel chimneys is specifically described in BS4207.NOTEThe titles of the publications referred to in this standard are liste
14、d on the inside back cover.2 DefinitionsFor the purposes of this Part of BS7335, the definitions given in BS3446-1 apply, together with the following.2.1 gunningthe hot or cold application of a refractory material by means of a pneumatic gun1)2.2 predampingthe process of mixing an amount of water, l
15、ess than the total water content, with dry material prior to dry gunning2.3 dry gunninga gunning process in which dry or predamped material is pneumatically conveyed to a nozzle where water is added2.4 wet gunninga gunning process in which concrete premixed with the total water content is conveyed u
16、nder pressure to a nozzle where air is used to propel the concrete into position2.5 hot gunningthe repair of a hot furnace lining by gunning2.6 material delivery hosehose used for conveying the gunning material from the gun to the nozzle2.7 panelthe minimum area of lining that is gunned in any conti
17、nuous operation3 PlanningNOTEThe installation should be planned in detail, in advance, so that work on site can proceed quickly and efficiently. The check list in 3.1 to 3.19 is given as an aid to drawing up such a plan.3.1 The safety requirements of the site should be considered, taking guidance wh
18、ere necessary from appropriate publications by the Health and Safety Executive. (See7.11.)3.2 A drawing detailing the materials of construction, the thickness of the lining layer(s), specification and arrangement of anchors, and other features, such as expansion allowance and joint arrangements, sho
19、uld be available.3.3 The extent of the job and the time available should be determined so that the required rate of installation may be calculated and an appropriate schedule for gunning prepared. Allowance should be included for any preparation of the shell which may be necessary, including the fix
20、ing of anchors.3.4 The number of men required to enable each panel of the lining to be placed continuously and correctly in the allocated time should be established.3.5 The material storage conditions and storage duration should be evaluated so that suitable packaging, for example hermetically seale
21、d drums or paper sacks, may be agreed. If possible gunning material should be ordered well in advance and delivered to site shortly before installation commences.3.6 A water supply of appropriate quality, capacity and temperature should be provided.3.7 Materials handling and waste disposal facilitie
22、s should be provided as appropriate for the materials and equipment involved.3.8 The number and type of formers, profile boards, scaffolding and staging required to achieve the planned installation should be determined, and prepared and installed prior to commencement of refractories installation.3.
23、9 Guns, nozzles, predamping equipment, and hoses for air, water and gunning material, appropriate for the planned installation, should be provided. Wear of components within the gunning equipment, and the possible effect of the inclusion of trace materials from this source in the gunned lining, shou
24、ld be assessed and appropriatecounter-measures taken where necessary.1) Repeated from BS3446-1.BS7335-2:19912 BSI 01-20003.10 Suitable electrical power supplies should be arranged, with due regard to voltage, frequency, current and phase requirements. Artificial lighting should be provided, if neces
25、sary.3.11 A compressed air supply for gunning equipment should be arranged. An existing on-site air supply may be adequate in some cases but provision of an air compressor is usually necessary.3.12 If necessary, auxiliary heating or cooling should be arranged, for example space heating or water cool
26、ing of the shell of the unit to be lined.3.13 The optimum siting of the various items of gunning equipment for efficient operation should be decided.3.14 A suitable welding procedure for anchors should be agreed.3.15 The size of panels to be gunned and the sequence of panel installation should be de
27、cided, if not specified in the vessel design. If the size and shape of the vessel are suitable, square panels of1m to2m side are usually employed.3.16 If not already designated (in a working drawing), the refractories manufacturer/supplier or the furnace designer should be consulted regarding the ty
28、pe and spacing of joints between panels.3.17 The curing and drying out procedure to be adopted should be agreed (seeclauses11 and12.3.18 If required, a quality control procedure should be agreed for gunning materials (seeclause5)and/or for the gunned lining, samples taken from it or samples fabricat
29、ed simultaneously with it (seeclause13).3.19 If required, the quality of workmanship and the efficiency of the equipment may be assessed at the commencement of the operation.4 PersonnelOperations directly involved in installation by gunning are as follows:a) nozzle operation;b) gun operation;c) feed
30、ing the gun;d) trowelling off and removal of rebound;e) curing.With certain types of gun, more than one operation may be performed by a single operator. However, with most types of gun a minimum crew of two men is required, a nozzleman and a gun operator. The gun operator may also feed material to t
31、he gun, and both men may perform the other operations on completion of gunning each panel of the lining. The number of men employed may be increased for faster installation.If predamping is undertaken using a batch type mixer (see7.7), additional personnel may be required to feed, operate and empty
32、the mixer and to transport the predamped material to the gun. If a continuous type mixer is used and arranged to feed directly into the gun, it is usually possible to proceed without extra personnel.5 Gunning materials5.1 Quality controlThese recommendations are concerned with the quality of the gun
33、ning material as tested prior to installation. The quality of the gunned lining, which depends on both the quality of the gunning material and on the method of installation, is described in clause13.Any problem associated with the gunning material will be compounded in terms of time and expense if i
34、t remains undetected until after installation, particularly if it causes failure on commissioning or in service. It is recommended, therefore, that acceptable limits for appropriate properties of the gunning material should be agreed between the parties concerned, and that supplies of the gunning ma
35、terial should be sampled and tested to ensure that the agreed requirements are met. The following options may be considered for quality control of supplies of gunning material.a) It may be agreed between the parties concerned that the quality control procedures of the refractories manufacturer/suppl
36、ier are adequate, particularly where an accredited quality assurance scheme is operated. (SeeBS5750).b) A scheme of sampling and testing specific to the job in hand may be agreed between the parties concerned. (See,for example, the sampling scheme and testing procedures in BS1902-7.)If option b) is
37、implemented, the sampling of the material is most easily carried out at some stage before final palleting or storage of the consignment, such as at the end of the manufacturers production line. Only whole bags or containers should be taken as samples. Selected samples should be stored in accordance
38、with the guidance given in5.2 until required for the preparation of test pieces, in order to avoid deterioration.NOTEProperties obtained from test pieces prepared by casting will not necessarily agree with those for gunned test panels or samples taken from the installed lining.BS7335-2:1991 BSI 01-2
39、000 35.2 StorageAll gunning materials should be used as soon as possible after manufacture, since they deteriorate during storage. Storage time may be reduced by arranging for the manufacturer/supplier to deliver fresh stock shortly before the work commences.No precise storage life can be quoted, bu
40、t, as a guide, the manufacturers of most gunning materials aim for a storage life of at least6months under good conditions. Gunning material in torn, punctured or open containers should be discarded. If undated material is to be stored, it should be stamped with the delivery date or batch number.For
41、 prolonged storage times, the gunning material should be kept in a clean, dry, well-ventilated building. It should be stored off the ground on a ventilated platform (e.g.a pallet) and placed under a cover (e.g.a tarpaulin), arranged so as to prevent any ground moisture from causing condensation or h
42、igh humidity under the cover.Gunning materials should not be stored at temperatures above35C immediately before use, as rapid setting may result. In cold conditions, the precautions recommended in8.5.2 may be taken.After being stored for some time, gunning material from the bottom of stacks may have
43、 lumps in it. These should break down when lightly rubbed between the fingers. If they do not, the material may have hydrated and the whole bag should be discarded.Storage life depends on many factors, including the type of aggregate, cement, additives, packaging and storage conditions. Some additiv
44、es, such as accelerators or inhibitors, may themselves deteriorate in storage. Gunning materials may be supplied in various types of container, from hermetically sealed drums to multi-walled paper sacks. Whilst better quality containers provide better protection in adverse storage conditions, they d
45、o not necessarily extend storage life. Some gunning materials may deteriorate even when stored in hermetically sealed containers.Where the condition of the gunning material after storage is uncertain or any doubts exist, the refractories manufacturer/supplier should be consulted.6 Water supply6.1 Qu
46、alityThe water for mixing to make the concrete should be clean, free from harmful matter and preferably of drinking quality to avoid the presence of dissolved chemicals which might have adverse effects on the setting or refractory properties of the gunned material. If there is any uncertainty, sampl
47、es of water should be taken for analysis. (SeeBS3148.)6.2 Capacity6.2.1 GeneralThe water supply should conform to the conditions of feed rate and pressure detailed in6.2.2 and6.2.3. If the mains water supply is inadequate, a water pump should be used (seeclause7).6.2.2 Feed rateThe supply rate requi
48、red depends on the number and capacity of the guns and predamping machines to be used, the water addition required for the materials to be installed, and the proposed installation rate. As a guide, a supply of30L/min would be sufficient to supply one predamping machine and one gun operating at a hig
49、h feed rate and with a high water addition.6.2.3 PressureThe minimum water supply pressure should be2.8bar2), plus0.1bar per metre of lift from the supply location to the nozzle.6.3 TemperatureThe water temperature should normally be in the range5C to25C. In cold conditions a heated water supply may be used (see8.5.2). A heated water supply may be obtained by placing immersion heater(s) in the water tank (if used), or by using a water pump with an integral heater.7 Equipment7.1 GeneralThe number, type and capacity of guns and hoses required will be dependent o
