BS DD ISO TS 3716-2006 Hydrometry - Functional requirements and characteristics of suspended-sediment samplers《液体比重测定法 悬浮沉积物取样器的功能要求和特性》.pdf

《BS DD ISO TS 3716-2006 Hydrometry - Functional requirements and characteristics of suspended-sediment samplers《液体比重测定法 悬浮沉积物取样器的功能要求和特性》.pdf》由会员分享，可在线阅读，更多相关《BS DD ISO TS 3716-2006 Hydrometry - Functional requirements and characteristics of suspended-sediment samplers《液体比重测定法 悬浮沉积物取样器的功能要求和特性》.pdf（20页珍藏版）》请在麦多课文档分享上搜索。

1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58characteristics of suspended-sediment samplersICS 17.120.20Hydrometry Functional requirements and D

2、RAFT FOR DEVELOPMENTDD ISO/TS 3716:2006DD ISO/TS 3716:2006This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 31 October 2006 BSI 2006ISBN 0 580 49389 Xan international Standard, to extend the life of the Technical Specification or to withdr

3、aw it. Comments should be sent to the Secretary of the responsible BSI Technical Committee at British Standards House, 389 Chiswick High Road, London W4 4AL.The UK participation in its preparation was entrusted to Technical Committee CPI/113, Hydrometry.A list of organizations represented on CPI/113

4、 can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Amendments issued since publicationAmd. No. Date Commentsthat UK experience can be reported to the international or

5、ganization responsible for its conversion to an international standard. A review of this publication will be initiated not later than 3 years after its publication by the international organization so that a decision can be taken on its status. Notification of the start of the review period will be

6、made in an announcement in the appropriate issue of Update Standards.According to the replies received by the end of the review period, the responsible BSI Committee will decide whether to support the conversion into National forewordThis Draft for Development was published by BSI. It is the UK impl

7、ementation of ISO/TS 3716:2006. This publication is not to be regarded as a British Standard.It is being issued in the Draft for Development series of publications and is of a provisional nature. It should be applied on this provisional basis, so that information and experience of its practical appl

8、ication can be obtained.Comments arising from the use of this Draft for Development are requested so Reference numberISO/TS 3716:2006(E)TECHNICAL SPECIFICATION ISO/TS3716First edition2006-08-15Hydrometry Functional requirements and characteristics of suspended-sediment samplers Hydromtrie Spcificati

9、ons de fonctionnement et caractristiques des appareils dchantillonnage pour la dtermination des charges sdimentaires en suspension DD ISO/TS 3716:2006ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Requirements of samplers. 1 5 Chara

10、cteristics of suspended-sediment samplers . 3 6 Types of samplers 3 6.1 Open containers 3 6.2 Vertical and horizontal cylinders 4 6.3 Bottle samplers . 4 6.4 Pumping samplers 5 6.5 Single-stage samplers 6 6.6 Point-integrating samplers 7 6.7 Depth-integrating samplers . 8 6.8 Clean samplers . 8 7 Mo

11、dels of samplers 9 Bibliography . 11 DD ISO/TS 3716:2006iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committ

12、ees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the Int

13、ernational Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International

14、Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In other circumstances, particularly when there is an urgent market requirement for such docu

15、ments, a technical committee may decide to publish other types of normative document: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication if it is approved by more than 50 % of the members of the

16、parent committee casting a vote; an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An ISO/PAS or ISO/TS is reviewed after three years in

17、 order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an International Standard or b

18、e withdrawn. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO/TS 3716 was prepared by Technical Committee ISO/TC 113, Hydrometry, Subcommittee SC

19、6, Sediment transport. This first edition of ISO/TS 3716 cancels and replaces ISO 3716:1977, which has been technically revised. DD ISO/TS 3716:2006vIntroduction Suspended-sediment samplers are used to collect a representative sample of the water-sediment mixture of rivers and streams. Ideally, the

20、sampler should be able to collect samples that represent the mean concentration of suspended sediment or define the horizontal and vertical variation of suspended-sediment concentration so that the mean concentration can be determined. Samplers have gradually evolved from those that collect an insta

21、ntaneous sample at one point in a stream or river to streamlined samplers that collect time and/or depth-integrated samples. There are a number of different types of samplers available for collecting suspended sediment, including open containers, vertical and horizontal cylinders, bottle samplers, p

22、umping samplers, single-stage samplers, point-integrating samplers and depth-integrating samplers. Some samplers have also been adapted to enable the collection of clean (uncontaminated) samples of trace metal and organic compounds that are commonly associated with suspended sediment in streams and

23、rivers. DD ISO/TS 3716:2006blank1Hydrometry Functional requirements and characteristics of suspended-sediment samplers 1 Scope This Technical Specification specifies the functional requirements and characteristics of the different types of suspended-sediment samplers. NOTE The units of measurement u

24、sed in this Technical Specification are SI units. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including a

25、ny amendments) applies. ISO 772, Hydrometric determinations Vocabulary and symbols 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 772 and the following apply. 3.1 isokinetic intake velocity of the suspended-sediment sampler equals the ambient stream

26、 velocity 4 Requirements of samplers In order that the samples taken by a sampler are truly representative of the sediment concentration of a stream at a point of sampling, the ideal sampler should fulfil the following technical requirements. a) The sampler shall be streamlined to reduce drag and to

27、 minimize disturbances to normal sediment flow. b) The velocity of inflow in the mouth of the sampler, nozzle or sampling tube shall be isokinetic or as close as possible to the velocity of the current of water at the sampling point, irrespective of what this velocity may be or irrespective of what

28、the depth of submergence at this point may be. This aspect is most important if large sampling errors are to be avoided. c) The mouth/intake of the sampler shall always face into the current at the sampling point. d) The mouth/intake of the sampler shall be outside the zone of the disturbances of th

29、e flow set up by the body of the sampler and its operating gear, and the flow lines shall be disturbed as little as possible, especially near the mouth. DD ISO/TS 3716:20062 e) Filling arrangements shall be smooth so that there is no sudden inrush of water-sediment mixture; the air escaping from the

30、 sampler shall not hinder the entry of the sample; this necessitates a separate port for air exhaust. f) The sampler shall be able to collect samples at the desired depth without the samples being disturbed or contaminated by the water-sediment mixture at other points while the sampler is being rais

31、ed or lowered. g) It shall be possible to take a sample exactly when and where it is required, in particular when sampling close to the streambed. h) The sampler shall be portable, yet sufficiently heavy to minimize deflection of the supporting cable from the vertical due to current drag. i) The sam

32、pler shall be simple in design and robust in construction and shall require minimum care in maintenance and operation. j) The removable-type container within the sampler shall be easily removed, readily capped or sealed and easily transported to a laboratory without loss of contents. Alternatively,

33、if the container forms part of the sampler, it shall be installed so as to secure complete drainage of the contents. k) The volume of the sample collected by the sampler shall be sufficient for determining the concentration and size distribution of the sediment. The minimum sample size is generally

34、0,5 l. l) Depth-integrating samplers should be lowered or raised at a uniform and slow speed, a fraction of the current velocity (for example, between 1/15 and 2/5 see Note). NOTE Depth integration (with uniform vertical motion see Figure 1): A v t = V, assuming v = vn(1) i = k v, where k = vn/v (2)

35、 h = i t (3) where A is the area of the mouth or tube; v is the current velocity; vnis the velocity in the mouth/intake (nozzle) of the sampler; t is the maximum duration of sampling; V is the sample volume to be taken; i is the uniform rate for sampler movement; k is the transit rate ratio; h is th

36、e maximum vertical distance for sampling. From Equations (1), (2) and (3): VhkA= (4) For example, with A = 28,3 mm2( 6 mm), k = 1/10 and V = 0,5 l, the maximum depth of sampling is 1,76 m. If the flow depth is greater, sampling should be done with two or more sections in the vertical. DD ISO/TS 3716

37、:20063Key A area of the mouth or tube v current velocity vnvelocity in the mouth/intake (nozzle) of the sampler t maximum duration of sampling V sample volume to be taken i uniform rate for sampler movement h maximum vertical distance for sampling Figure 1 Schematic diagram of a suspended-sediment s

38、ampler and the factors affecting sample volume 5 Characteristics of suspended-sediment samplers Since the sampling conditions encountered in streams vary widely, a single sampler for all the conditions cannot be recommended. Factors such as availability, cost and specific requirements of the samplin

39、g also influence the choice of the sampler to a great extent. The different types of samplers include open containers, vertical and horizontal cylinders, bottle samplers, pumping samplers, single-stage samplers, point-integrating samplers and depth-integrating samplers. All of these types of sampler

40、s can collect a representative sample of the water-sediment mixture in a river or stream under the right conditions, but many of them cannot be used in rivers with swift currents and a non-uniform distribution of sediment concentration. For general use in rivers and streams, point-integrating and de

41、pth-integrating samplers are recommended. The use of trade, product or firm names in this document is for descriptive purposes only and does not imply endorsement. 6 Types of samplers 6.1 Open containers This type of sampler consists of an ordinary pail, can or open bottle. The sample is collected b

42、y holding the container under the surface of the water or by lowering it to the water surface with a rope or cable. The filled container can be sealed for transport and subsequent analysis or the sample can be transferred into another container that can be sealed. DD ISO/TS 3716:20064 The limitation

43、 of these samplers is that they can only collect a sample at the water surface. Representative samples will be collected only if the water-sediment mixture is thoroughly mixed and free of silt and sand. 6.2 Vertical and horizontal cylinders These samplers (see Figure 2) are typically made of steel,

44、brass or plastic. They are made in various diameters and lengths. The cylinder is lowered to the desired sampling point with the valves at each end of the cylinder in the open position. The sample is collected by closing the valves and retrieving the cylinder. The valves are actuated by an electrica

45、l impulse or by sending a weight down the suspension cable to trip spring-loaded valves. The sample is typically transferred to another container so the cylinder can be reused. These samplers, particularly the vertical cylinders, offer considerable resistance to flow and are only stable at very low

46、velocities. Vertical cylinders cannot sample close to the streambed. Horizontal samplers can sample near the streambed. Figure 2 Kemmerer sampler 6.3 Bottle samplers There are many different variations of bottle samplers. They generally consist of a weighted container to hold a 0,5 l to 2 l sample b

47、ottle. The sampler is lowered to the desired depth by a rope or cable and then the cap is removed from the bottle to collect the sample. Some models have the capability of both opening and closing the bottle cap so the sample is sealed and no intermixing of the sample with the water-sediment mixture

48、 in the river occurs while the sampler is being retrieved. These samplers offer considerable resistance to flow and are only stable at very low velocities. Samples cannot typically be collected close to the streambed. The potential for intermixing of the sample and water-sediment mixture in the rive

49、r is high for those samplers that cannot be sealed at the sampling point. DD ISO/TS 3716:200656.4 Pumping samplers 6.4.1 General There are two types of pumping samplers used for collecting suspended-sediment samples: those with a fixed orifice that are operated in automatic mode and those with a moveable orifice that are deployed from a boat, walkway or bridge. 6.4.2 Fixed-orifice samplers Fixed-orifice samplers (Figure 3) typically are used at sites where personnel are not available to take samples manually, such as