1、BRITISH STANDARD BS6068-6.7: 1994 ISO5667-7: 1993 Water quality Part 6: Sampling Section 6.7 Guidance on sampling of water and steam in boiler plants UDC 614.777:556.11:620.113BS6068-6.7:1994 This British Standard, having been prepared under the directionof the Environment andPollution Standards Pol
2、icy Committee, was published underthe authority of the Standards Board and comes intoeffect on 15March1994 BSI02-1999 The following BSI references relate to the work on this standard: Committee reference EPC/44 Draft for comment 91/55510DC ISBN0580229459 Committees responsible for this British Stand
3、ard The preparation of this British Standard was entrusted by the Environment and Pollution Standards Policy Committee (EPC/-) to Technical CommitteeEPC/44, upon which the following bodies were represented: Association of Consulting Scientists British Association for Chemical Specialities British Ga
4、s plc Chemical Industries Association Convention of Scottish Local Authorities Department of the Environment (Water Directorate) Department of the Environment for Northern Ireland Department of Trade and Industry (Laboratory of the Government Chemist) Electricity Association Industrial Water Society
5、 Institution of Gas Engineers Institution of Water Officers Institution of Water and Environmental Management National Rivers Authority Royal Institute of Public Health and Hygiene Royal Society of Chemistry Scottish Association of Directors of Water and Sewerage Services Soap and Detergent Industry
6、 Association Water Companies Association Water Research Centre Water Services Association of England and Wales The following bodies were also represented in the drafting of the standard through subcommittees and panels: Automatic Vending Association of Great Britain British Association for Chemical
7、Specialities British Geological Survey Convention of Scotish Local Authorities Department of Trade and Industry (Warren Spring Laboratory) Electricity Association Institute of Oceanographic Sciences Power Generation Contractors Association (BEAMA Ltd.) Society for General Microbiology Society of Che
8、mical Industry University of Bradford Amendments issued since publication Amd. No. Date CommentsBS6068-6.7:1994 BSI 02-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Sampling General aspects 2 5 Sampling equipm
9、ent 3 6 Sampling locations 8 7 Collection of water samples 10 8 Collection of steam samples 10 9 Preservation of samples 10 10 Sample identification and records 10 Annex A (informative) Sampling points in boiler plants 11 Annex B (informative) Coolers 12 Annex C (informative) Report Sampling of wate
10、r and steam in boiler plants 14 Figure 1 Schematic water sampling system 3 Figure 2 Example of a straight circular sampling probe for sampling soluble species 4 Figure 3 Example of a directional sampling probe for sampling particulates in water 4 Figure 4 Example of a water sampling probe for both s
11、oluble and particulate sampling 5 Figure 5 Examples of sampling probes for sampling saturated steam 5 Figure 6 Example of a steam sampling probe, multiport type 6 Figure 7 Radii of circles for dividing a circular pipe into annuli of equal areas 7 Figure 8 Typical capillary sampler arrangement 9 Figu
12、re A.1 Location of principal sampling points 11 Figure B.1 Example of a typical sample cooler 13 Table 1 Recommended minimum mass flow through sampling probe for various steam pressures 6 Table A.1 Typical sample conditions at various sampling points in steam and water circuits 11 Table B.1 Operatin
13、g parameters of a sample cooler 12 List of references Inside back coverBS6068-6.7:1994 ii BSI 02-1999 National foreword This Section of BS6068 has been prepared under the direction of the Environment and Pollution Standards Policy Committee and is identical with ISO5667-7:1993 Water quality Sampling
14、 Part 7: Guidance on sampling of water and steam in boiler plants, published by the International Organization for Standardization (ISO). It supersedes BS1328:1969 and BS3285:1960 which are withdrawn. The international standard was prepared by Technical Committee147, Water quality, of the Internatio
15、nal Organization for Standardization (ISO) with the active participation and approval of the UK. BS6068 is being published in a series of Parts subdivided into Sections that will generally correspond to particular international standards. Sections are being, or will be, published in Part 1 to Part 7
16、 which, together with Part 0, are listed below. Part 0: Introduction; Part 1: Glossary; Part 2: Physical, chemical and biochemical methods; Part 3: Radiological methods; Part 4: Microbiological methods; Part 5: Biological methods; Part 6: Sampling; Part 7: Precision and accuracy. This Section of BS6
17、068 is one of a group of standards dealing with the sampling of specific types of water. It should be read in conjunction with BS6068-6.1, BS6068-6.2 and BS6068-6.3, which deal respectively with the design of sampling programmes, sampling techniques and the preservation and handling of samples. The
18、general terminology is in accordance with BS6068-1 and in particular Section 1.2. Cross-references International standard Corresponding British Standard BS 6068 Water quality ISO5667-1:1980 Section 6.1:1981 Guidance on the design of sampling programmes (Identical) ISO5667-2:1991 BSEN25667-2:1993 Wat
19、er quality. Sampling Part 2: Guidance on sampling techniques (Identical) BS6068 Water quality ISO5667-3:1985 Section6.3:1986 Guidance on the preservation and handling of samples (Identical) ISO6107-1:1986 Section1.1:1987 Terms relating to types of water, and treatment and storage of waste water (Ide
20、ntical) ISO6107-2:1989 Section1.2:1990 Additional terms relating to types of water, and treatment and storage of water and waste water, and terms used in sampling and analysis of water (Identical) ISO8199:1988 Section4.2:1989 Guide to the enumeration of micro-organisms by culture (Identical)BS6068-6
21、.7:1994 BSI 02-1999 iii 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
22、This document comprises a front cover, an inside front cover, pages i to iv, pages1 to 14, 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 theinside front cover.iv bl
23、ankISO5667-7:1993(E) BSI 02-1999 1 1 Scope This part of ISO5667 recommends procedures and equipment for sampling water and steam in boiler plants including examples of sampling apparatus, to provide samples for physical and chemical analysis that are representative of the main body of water or steam
24、 from which they are taken. The procedures for sampling water apply to raw water; make-up water; boiler feed water; condensate; boiler water; cooling water. The procedures for sampling steam cover both saturated and superheated steam. This part of ISO5667 does not apply to the sampling of water and
25、steam in nuclear power plants. Figure 2 to Figure 6 are only given as examples of sampling apparatus. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO5667. At the time of publication, the editions indic
26、ated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO5667 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid Internatio
27、nal Standards. ISO5667-1:1980, Water quality Sampling Part 1: Guidance on the design of sampling programmes. ISO5667-2:1991, Water quality Sampling Part 2: Guidance on sampling techniques. ISO5667-3:1985, Water quality Sampling Part 3: Guidance on the preservation and handling of samples. ISO6107-1:
28、1986, Water quality Vocabulary Part 1. ISO6107-2:1989, Water quality Vocabulary Part 2. ISO8199:1988, Water quality General guide to the enumeration of micro-organisms by culture. 3 Definitions For the purposes of this part of ISO5667, the following definitions apply. 3.1 isokinetic sampling a techn
29、ique in which the sample from a water or steam stream passes into the orifice of a sampling probe with a velocity equal to that of the stream in the immediate vicinity of the probe ISO6107-2 3.2 sampler a device used to obtain a sample of water or steam, either discretely or continuously, for the pu
30、rpose of examination of various defined characteristic ISO6107-2 3.3 sampling point the precise position within a system from which samples are taken ISO6107-2 3.4 sampling probe that part of sampling equipment which is inserted into a body of steam or water and into which the sample initially passe
31、s ISO6107-2 3.5 sampling line the conduit which leads from the sampling probe to the sample delivery point or the analysing equipment ISO6107-2 3.6 sample delivery point the end of a sampling line, often remote from the sampling probe, from which a sample is removed, either discretely or continuousl
32、y, for examination 3.7 raw water water which has received no treatment whatsoever, or water entering a plant for further treatment ISO6107-1 3.8 make-up water water which has to be added to the system in order to make up for losses 3.9 condensate condensed steam from power plants or processes, which
33、 is not mixed with any other water 3.10 boiler water the water present in a operational boilerISO5667-7:1993(E) 2 BSI 02-1999 3.11 feed water the water consisting of the condensate (3.9) and the make-up water (3.8) and which passes through the feed pump or injector 3.12 saturated steam steam having
34、a temperature equal to the saturation temperature corresponding to its pressure 3.13 superheated steam steam having a temperature above the saturation temperature corresponding to its pressure 4 Sampling General aspects 4.1 Introduction A prerequisite of any sampling system is that it should extract
35、 a sample representative of the fluid in the given part of the circuit for subsequent analysis. Problems are most likely to arise when more than one phase is present. 4.2 Sampling system General information The sampling system for the collection of samples of water and steam consists of the followin
36、g parts (seeFigure 1): the sampling probe; a sampling line, including valves and fittings; a cooler (this can be omitted when the sample temperature is permanently below 50C); a sample delivery point. The design of the sampling system and the selection of materials are influenced by the analyses to
37、be carried out and the required accuracies; the chemical composition of the water or steam to be examined; the temperature and pressure at the sampling point; the chemical composition of the cooling water. For most applications, all the parts of sampling equipment in contact with the sample should b
38、e made of stainless steel, 18Cr8Ni. In some cases, other materials may be used, for example, copper for sampling from low pressure boilers. It is essential that these are suitable for the use for which they are required, and they should not interact with the constituents of the sample. The various p
39、arts of the sampling system are described in more detail in clause 5. 4.3 Sampling points General guidelines Sampling points should be positioned in those parts of the circuit where the composition, or changes in the composition, of the water or steam need to be determined. Figure A.1 shows typical
40、sampling locations in the steam/water circuit. A sample point for a shell boiler should be located a minimum of150mm below the normal working level of the boiler. It is recommended that the sample should be taken during the normal boiler operations, but not when the boiler is being fired. Whenever p
41、ossible, samples should be taken from flowing systems. Stagnant areas should be avoided, unless samples are specifically required from such areas (e.g. wet stored boilers). Where waters of different origin and composition are blended, or chemicals are added, sampling points should be positioned wher
42、e complete mixing has taken place. In most cases, this can be achieved by sampling downstream of a turbulence promoter such as a valve, pump or pipe bend. To obtain a representative sample of particulate matter in water flowing in a pipe, it is necessary to a) sample at a location where the particul
43、ate matter is uniformly distributed in the pipe; b) withdraw a representative sample from the bulk fluid; c) transport the sample in the sample line to the sample delivery point, with minimum changes in either the concentration or nature of the particulate matter. To meet these criteria for systems
44、with turbulent flow, the sampling points should preferably be installed in vertical pipework and the sample taken isokinetically. If this is not possible, sampling points should be positioned beside horizontal piping at least10internal pipe diameters downstream and5internal pipe diameters upstream o
45、f any flow disturbance such as pumps, valves and pipe bends. Further guidance on choosing sampling points is given in clause 6.ISO5667-7:1993(E) BSI 02-1999 3 5 Sampling equipment 5.1 Materials The materials selected for the sampling probe, including fittings, and the weld material used to install t
46、he probe should be compatible with the piping material and the fluid being sampled. The design of the welded joint and the welding and inspection procedures should comply with all applicable codes to ensure an adequate, reliable joint. The material used for the sampling probes should also be selecte
47、d so that the sample is not contaminated by the material. For example, a system containing brass components would not be suitable if it was required to determine total copper. 5.2 Water sampling probes For collecting samples of homogeneous water, an off-take connection as shown schematically in Figu
48、re 2 is recommended. When it is required to sample water containing particulate matter, ideally the sample needs to be taken isokinetically. Representative sampling of particulate matter is important, for example, in the estimation of corrosion products in a system. Experience has shown that, for so
49、me applications, a straight probe (off-take connection) will be sufficient. In other cases, the use of a directional probe will be necessary. The choice of either a straight or directional probe is best made by experimentation using both designs. The probe should face into the direction of flow. The directional probe should be used when sampling water containing particulate matter of a wide range of particle sizes. A straight probe should be considered when s
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