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1、BRITISH STANDARD MARINE SERIES CONFIRMED AUGUST 1980 BS MA 27:1974 Specification for Sight-flow indicators for tank overflow systems UDC 629.12.011.52.004.53:621.642.2.057.6 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:16:00 GMT+00:00 2006, Uncontrolled Co
2、py, (c) BSI BS MA 27:1974 This British Standard having been approved by the Shipbuilding and Marine Industry Standards Committee, was published under the authority of the Executive Board on 15 January 1974 BSI 02-2000 The following BSI references relate to the work on this standard: Committee refere
3、nce SME/3 Draft for comment 72/35130 ISBN 0 580 08210 5 Foreword This British Standard has been prepared under the authority of the Shipbuilding and Marine Industry Standards Committee and is based on a proposal of the British Ship Research Association. In general, tanks built into the ship structur
4、e or of separate construction require the provision of a high level alarm or other device such as a sight-flow indicator, to detect overflow conditions. This standard concerns a basic range of sight-flow indicators which are intended to be used in the overflow piping systems of oil or water tanks. T
5、his standard makes reference to the following British Standards: BS 1452, Grey iron castings. BS 1832, Oil resistant compressed asbestos fibre jointing. BS 3463, Observation and gauge glasses for pressure vessels. BS 3643, ISO metric screw threads Part 2: Limits and tolerances for coarse pitch serie
6、s threads. BS 3692, ISO metric precision hexagon bolts, screws and nuts. BS 4439, Screwed studs for general purposes. BS 4504, Flanges and bolting for pipes, valves and fittings. Metric series. NOTEAttention is drawn to certification facilities offered by BSI; see the inside back cover of this stand
7、ard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document compr
8、ises a front cover, an inside front cover, pages i and ii, pages 1 to 4, 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 amendment table on the inside front cover. Amendments issued sin
9、ce publication Amd. No.DateComments Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:16:00 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 27:1974 BSI 02-2000i Contents Page ForewordInside front cover 1Scope1 2Type1 3Designation1 4Nominal sizes1 5Pressure and
10、 temperature rating1 6Design characteristics1 7Materials2 8Quality of manufacture2 9Dimensions and tolerances2 10Tests2 11Preparation for despatch3 12Marking3 13Information to be supplied with an enquiry or order3 Appendix A Installation of sight-flow indicators4 Figure 1 Face-to-face dimensions and
11、 minimum nozzle diameters for sight-flow indicators4 Table 1 Requirements for plate glass ports for sight-flow indicators2 Table 2 Material specification2 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:16:00 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blan
12、k Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:16:00 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 27:1974 BSI 02-20001 NOTEUsers of this British Standard, Marine Series should note that while observing the requirements of the standard they should at th
13、e same time ensure compliance with such statutory requirements, rules and regulations as may be applicable to the individual ship concerned. 1 Scope This British Standard specifies the general requirements with regard to design, materials and size range of transparent glass ported straight-through t
14、ype sight-flow indicators intended for use in the overflow piping systems from tanks containing oil or water. The sight-flow indicator bodies, having in-line branches, and the cover plates for securing the plate glass ports are of cast iron construction. The range of nominal sizes specified is from
15、32 mm to 200 mm inclusive. 2 Type 2.1 Sight-flow indicators specified in this standard shall conform to the following types as required by specific application. Type A. Sight-flow indicators for flammable fluids incorporating special features to ensure integrity of the indicator during fire conditio
16、ns. Type B. Sight-flow indicators for non-flammable fluids. 2.2 Both types of sight-flow indicator shall be of the double-sided porthole type with body of cylindrical cross-section at right angles to the direction of fluid flow. The indicators have ranged “in-line” inlet and outlet circular body bra
17、nches of equal size. 2.3 An internal convergent-type nozzle is incorporated in the sight-flow indicator and the minimum internal diameters of the nozzles are given in Figure 1. 2.4 These types of sight-flow indicators are intended for gravity flow and when specified shall be installed with the axis
18、vertical as shown in Figure 1. 2.5 For special features applicable to Type A indicators see 6.4. 3 Designation The sight-flow indicator shall be designated by the nominal adjoining pipe size as given in Clause 4. 4 Nominal sizes The nominal sizes of the sight-flow indicators, in mm, correspond to th
19、eir nominal bores, and are: 32, 40, 50, 65, 80, 100, 125, 150 and 200. 5 Pressure and temperature rating For the intended service of oil and water overflow, all sight-flow indicators shall have a pressure rating of 1.0 bar (0.10 MN/m2) and a temperature rating of 100 C. 6 Design characteristics 6.1
20、The sight-flow indicator body shall be a one-piece casting with integral inlet and outlet branches, the bores of which shall be circular on a common axis and the diameters in accordance with the nominal size range as stated in Clause 4. 6.2 The face-to-face dimensions of sight-flow indicators shall
21、be in accordance with Figure 1 and standard flanges shall be fitted in accordance with dimensions given in BS 4504 for NP6 rating. Flanges shall be at right angles to the axis of the branch bore and concentric with the bore, and the faces shall be parallel to each other. Flanges may have flat or rai
22、sed jointing faces and shall be drilled with bolt holes off centre lines. The body and branch wall thicknesses for the castings shall be based on branch thicknesses given in BS 4504 for NP6 rating. 6.3 The internal design of the body shall be such as to obviate, as far as is practicable, the splashi
23、ng of the liquid onto the glass ports at any condition of flow. For this purpose a convergent-type nozzle, of integral or separate form, shall be incorporated in the inlet branch of the indicator together with any other feature considered to be of assistance in preventing splashing of the liquid, su
24、ch as enlarging the diameter of the entry to the outlet portion of the body. The minimum diameter of the nozzle outlet shall be not less than the sizes given in Figure 1 in order that the minimum flow area shall be not less than 1.25 times the sectional area of the corresponding filling line as requ
25、ired by the classification societies. 6.4 The arrangement and specification of circular glasses for the sight-flow indicators shall be as follows. Type A. The manufacturer shall be responsible for the protective arrangement of the indicator by means of double glazing, or any other acceptable means t
26、o ensure that the indicators will satisfy the requirements of the fire test specified in 10.2 of this standard. Type B. Single glazing consisting of single glasses of toughened soda-lime in accordance with BS 3463-4. Licensed Copy: London South Bank University, London South Bank University, Sat Dec
27、09 02:16:00 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 27:1974 2 BSI 02-2000 6.5 The width of the annular bearing surface for the glass ports provided by the body and cover plates shall be not less than the thickness of the glass. 6.6 The dimensions for the toughened soda-lime plate glass port
28、s covering the nominal size range of sight-flow indicators are shown in Table 1. 6.7 The manufacturer shall ensure that the method adopted for effectively sealing and securing the plate-glass ports for both Type A and Type B indicators shall not cause damage or cracking of the glass. 6.8 A raised ar
29、row shall be cast on each side of the body indicating the direction of flow. Table 1 Requirements for plate glass ports for sight-flow indicators 7 Materials The materials used in the construction of the sight-flow indicators shall be in accordance with the minimum qualities given in Table 2. Other
30、materials may be used provided they are at least as suitable in all respects for the intended duty and are equally acceptable by the purchaser. Table 2 Material specification 8 Quality of manufacture 8.1 The castings shall have no detrimental defects such as porosity, blow holes, fins, attached foun
31、dry sand or scale on either the internal or external surfaces and the fluid passages shall be clean and smooth. The inside rim of the nozzle outlet shall be free from irregularities which may adversely influence the flow pattern of the fluid. 8.2 The edge of the plate glass ports shall be taped with
32、 suitable material to ensure edge protection against damage during assembly and subsequently when located in the recess. The cover gaskets shall be of such dimensions that will ensure complete coverage of the annular beating surface of the glass. 8.3 Where studs are used for the cover fastening, the
33、 holes for the studs shall not protrude through the rim of the body. The depth of insertion of the metal end of the studs shall be equal to the nominal diameter of the stud. The threads of the tapped holes shall be to the standard limits of tolerance class 6H (medium fit) as specified in BS 3643-2.
34、9 Dimensions and tolerances 9.1 All component parts for the sight-flow indicator shall be interchangeable between units of the same size from any one manufacturer. 9.2 The face-to-face dimensions for the sight-flow indicators given in Figure 1 shall be subject to a tolerance of 2 mm. 10 Tests 10.1 E
35、ach completed sight-flow indicator shall be leak-proof and mechanically sound when tested to 2.0 bar (0.20 MN/m2). The test shall be carried out using clean water and the test pressure maintained for sufficient time to permit proof and inspection but shall be not less than for a period of two minute
36、s duration. 10.2 In the case of Type A indicators, the manufacturer shall be able to produce a certificate endorsed by the relevant regulatory bodies stating that the design has been subjected to, and passed, a fire test of 800 C for 20 minutes during which time the fluid was maintained and circulat
37、ed at the normal working condition. 10.3 Where specified by the purchaser, a test certificate shall be issued by the manufacturer or regulatory body confirming that the sight-flow indicator has been tested in accordance with the requirements of this standard. Nominal size Glass ports Nominal diamete
38、rNominal thickness 32 40 50 65 80 100 125 150 200 mm 65 65 75 100 125 150 175 200 255 mm 6 6 6 6 6 6 6 12 12 ComponentMaterial Specification BS No.Designation Body Covers Glass ports Gaskets Grey cast iron Grey cast iron Toughened soda-lime glass Compressed asbestos fibre BS 1452 BS 1452 BS 3463-4 B
39、S 1832 Grade 12 Grade 12 Design stress 35 N/mm2 Cover fasteners Steel studs Steel nuts BS 4439 BS 3692 Grade 4.8 Grade 4 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:16:00 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 27:1974 BSI 02-20003 11 Preparation
40、 for despatch 11.1 After testing, each sight-flow indicator shall be drained, cleaned and dried, and where specified the body and covers shall be protected on the internal and external surfaces with a suitable corrosion resistant paint. When the sight-flow indicator is used in oil overflow systems i
41、t is recommended that the internal surfaces should not be painted unless the paint is of a special oil resistant type. 11.2 All exposed machined faces shall be adequately protected from corrosion and the plate glass ports protected against breakage. The branch openings shall be suitably sealed to pr
42、event the ingress of dirt or other foreign matter during storage or transit. 12 Marking All completed sight-flow indicators shall have the following markings either on the body or on a corrosion resistant plate securely attached: 1) The number of this British Standard i.e. BS MA 27 2) The type (see
43、2.1) 3) The manufacturers name or registered trade mark 4) The nominal size (see Clause 4). 13 Information to be supplied with an enquiry or order The following information shall be supplied by the purchaser when making an enquiry or placing an order for sight-flow indicators to this standard: 1) Th
44、e number of this British Standard i.e. BS MA 27 2) The type (see 2.7) 3) The nominal size (see Clause 4) 4) The quantity required 5) The quantity of spare glass ports if required 6) If a test certificate is required (see 10.2). Licensed Copy: London South Bank University, London South Bank Universit
45、y, Sat Dec 09 02:16:00 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 27:1974 4 BSI 02-2000 Appendix A Installation of sight-flow indicators When the sight-flow indicator is installed in the overflow pipe line it is essential that the arrow indicating the direction of flow is pointing downwards. A
46、n electric light of sufficient brilliance to ensure satisfactory illumination of the interior of the body should be sited as close as practicable to one of the plate glass ports of the sight-flow indicator. In order to ensure ideal visibility it is suggested that the sight-flow indicator should be i
47、nstalled in the pipeline so that the centre of the plate glass ports should be at a height not exceeding 1 600 mm above the viewing platform. Nominal size Face-to-face dimension L Nominal bore of tank filling line Minimum nozzle dia. d for flow area 25 % greater than sectional area of filling line 3
48、2 40 50 65 80 100 125 150 200 195 195 210 225 280 305 330 355 405 25 32 40 50 65 80 100 125 150 28 36 45 56 75 90 112 140 170 Dimensions in millimetres Figure 1 Face-to-face dimensions and minimum nozzle diameters for sight-flow indicators Licensed Copy: London South Bank University, London South Ba
49、nk University, Sat Dec 09 02:16:00 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 27:1974 BSI 02-2000 BSI Certification Trade Mark The Kitemark The British Standards Institution is the owner of a registered certification trade mark. It is usually associated with the words “approved to British Standard” as shown below, the number of the relevant British Standard being added. This mark may be used only by those licensed under the certification mark scheme operated by BSI. The presence of this mark on or in relation to a product is an assurance that the