IEC 61518 pdf download.Mating dimensions between differential pressure (type) measuring instruments and flanged-on shut-off devices up to 41 3 bar (41 ,3 MPa)
This International Standard is applicable to differential pressure (type) measuring instruments (instrument) with a shut-off device (manifold) directly bolted on to them. This standard specifies mating dimensions and tolerances, threads, bolts, and gaskets for a maximum allowable working pressure of 41 ,3 MPa (41 3 bar) at 38 °C. This standard does not apply to assemblies that provide additional sealing elements (adapters) between the instrument and the manifold. Where the possibility exists, shut-off devices shall be mounted on either side of the instrument, and all connections shall then meet this standard. Elements, such as flanged coupling joints, may apply this standard or parts thereof to increase standardization at the discretion of the supplier and the end-user. This standard is only valid for instrument and manifold flanges manufactured from a metallic material with yield strength equal to, or larger than, 1 90 N/mm 2 .
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 48:1 994, Rubber, vulcanized or thermoplastic – Determination of hardness (hardness between 1 0 IRHD and 1 00 IRHD) ISO 898-1 :1 999, Mechanical properties of fasteners made of carbon steel and alloy steel – Part 1 : Bolts, screws and studs ISO 1 629:1 995, Rubber and latices – Nomenclature ISO 3506 (all parts)
ISO 3601 -1 :1 988, Fluid systems – Sealing devices – O-rings – Part 1 : Inside diameters, cross- sections, tolerances and size identification code ISO 3601 -3:1 987, Fluid systems – Sealing devices – O-rings – Part 3: Quality acceptance criteria ASME B1 8.3.1 M:1 986 (R1 993), Screws, socket head cap (metric series) ASME B1 8.2.1 :1 996, Square and Hex Bolts and Screws Inch Series ASTM A1 93:1 999, Specification for alloy steel and stainless steel bolting materials for high- temperature service ASTM A449:1 993, Specification for quenched and tempered steel bolts and studs
Dimensions in figures and tables are in millimetres, except where stated otherwise. Leak-tight connection between the differential (type) measuring instrument and the flanged instrument manifold depends upon the conformance to the dimensions and the tolerances. 3.1 Connection dimensions at the differential pressure (type) instrument See figure 1 . 3.2 Connection dimensions at the shut-off device Two designs for the manifold facings are recommended: – Type A: design with an extended spigot (see figure 2); – Type B: design without an extended spigot (see figure 3). NOTE Type B design may also be suitable for differential pressure (type) transmitters, where the connecting dimensions are not in accordance with this standard. The user is responsible for ensuring compatibility for trans- mitters with different dimensions. 3.3 Seal rings The specifications for the flat ring are those of tables 1 and 2. The O-rings are in accordance with the ISO standards quoted. Materials and temperature limits for the flat rings and the O-ring are for reference only. It is the responsibility of the user to ensure compatibility between the selected gasket ring material and the process requirements, such as pressure, temperature, and chemical compatibility.22.214.171.124 O-Ring No suitable ISO-standardized O-ring is available for the manifold without the spigot. It is the user’s responsibility to apply O-rings according to a local standard. 3.4 Flange connection (see figures 4 and 5) Flange connections, as described, shall only be used within the defined limits for pressure and temperature of the instrument and manifold assembly.