API 7NRV 2020 pdf download.Specification for Drill String Non-return Valves.
0 Introduction This standard has been developed by users/purchasers and suppliers/manufacturers of Drill String Non-return Valve equipment intended for use in the petroleum and natural gas industry worldwide. This Standard is intended to give requirements and infor- mation to both parties in the selection, manufacture, testing and use of Drill String Non-return Valve equipment. Further, this Standard addresses requirements that set the minimum parameters with which the supplier/manufacturer must comply to claim conformity with this standard. Users of this standard should be aware that further or differing requirements might be needed for individual applications. This standard is not intended to inhibit a supplier/manufacturer from offering, or the user/purchaser from accepting, alternative equip- ment or engineering solutions. This may be particularly applicable where there is innovative or developing technology. Where an alternative is offered, the supplier/manufacturer should identify any variations from this standard and provide details. This document does not cover maintenance and inspection once the NRV has left the manufacturer and is in operation. These are important to the safety and reliability of the equipment and should be considered. 1 Scope This standard was formulated to provide the minimum acceptable requirements for Drill String Non-return Valve (NRV) equip- ment. It covers Drill String Non-return Valves, Non-return Valve Subs, Non-return Valve landing nipples, Non-return Valve Equalizing Heads and all components that establish tolerances and/or clearances which may affect performance or interchange- ability of the NRV equipment. Non-return Valve Subs, Non-return Valve landing nipples, Non-return Valve Equalizing Heads and NRVs manufactured by different facilities or manufacturers may be supplied as separate items. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this stan- dard.
3 Terms and definitions For the purposes of this standard, the following terms and definitions apply: 3.1 AQL: Acceptance quality level. 3.2 chloride stress corrosion cracking: Cracking under the combined action of tensile stress and corrosion in the pres- ence of chlorides and water. 3.3 design acceptance criteria: Defined limits placed on characteristics of materials, products, or services, established by the manufacturer to ensure conformance to the product design. 3.4 design verification test: Test performed to qualify a particular size, type and model of NRV equipment for a specific class of service. 3.5 end connection: NRV equipment/tubular connecting interface.
3.6 failure: Any condition of NRV equipment that prevents it from performing the design function. 3.7 fit: The geometric relationship between parts. 3.8 form: The essential shape of a product including all its component parts. 3.9 function: The operation of a product during service. 3.10 functional test: Test performed to confirm proper operation of NRV equipment. 3.11 heat treatment/heat treating: Alternate steps of controlled heating and cooling of materials for the purpose of chang- ing physical or mechanical properties. 3.12 interchangeable: Conforming in every detail, within specified tolerances, to both fit and function of a safe design but not necessarily to the form. 3.13 manufacturer: The principal agent in the design, fabrication and furnishing of NRV equipment, who chooses to comply with this Standard. 3.14 model: NRV equipment with unique internal part(s) and operating characteristics which differentiate it from other NRV equipment of the same type. 3.15 NDE: Nondestructive examination. 3.16 NRV: A Drill String Non-return Valve. 3.17 NRV Equalizing Head: Used to equalize the NRV on surface, venting any trapped pressure prior to the removal of the NRV from the drill string. 3.18 NRV equipment: The Drill String Non-return Valve, Non-return Valve Subs, Non-return Valve landing nipples, Non- return Valve Equalizing Heads and all components that establish tolerances and/or clearances which may affect performance or interchangeability of the NRV equipment. 3.19 NRV Sub / NRV Landing Nipple: A receptacle with internal sealing surfaces in which an NRV may be installed. 3.20 operating manual: A publication issued by the manufacturer which contains detailed data and instructions related to the design, installation, operation and maintenance of NRV equipment.