【国外标准】 Standard Specification for Glass Stopcocks with Polytetrafluoroethylene (PTFE) Plugs

This specification covers dimensional interchangeability requirements of glass stopcocks with polytetrafluoroethylene (PTFE) plugs for use in ordinary laboratory and industrial applications. However, it does not cover the design characteristics of the stopcock-plug assembly nor the physical or chemical properties of the materials used. Glass stopcocks with glass plugs or stopcocks for use in high-vacuum applications are not covered as well. The plug shall be manufactured from PTFE material of Types I and IV, extrusion and molding grade resins. Stopcocks, on the other hand, shall be manufactured from glass into one of various types: single straight-bore stopcock, single oblique-bore stopcock, double oblique-bore (three-way) stopcock, T-bore stopcock, or angled-bore stopcock. Tests for dimension conformity, taper, leak rate, and performance shall be performed and shall conform to the requirements specified.1.1 This specification covers standard dimensional requirements for obtaining, within practical limits, interchangeability in glass stopcocks (Note 1) with polytetrafluoroethylene (PTFE) plugs for ordinary laboratory and industrial applications. It covers dimensional interchangeability only and does not involve design characteristics of the item except where specified, nor does it involve physical or chemical characteristics of the material used. It does not cover glass stopcocks with glass plugs (Note 2) or stopcocks intended for use in high-vacuum work.NOTE 1: A stopcock is defined as consisting of a plug and barrel in assembled configuration.NOTE 2: Glass stopcocks with glass plugs are covered by Specification E675.NOTE 3: The dimensions pertaining to stopcocks were taken from the now obsolete Commercial Standard CS 21-58 of the U.S. Department of Commerce and Product Standard PS 28-70 published by the National Bureau of Standards.NOTE 4: Although glass is the most common material for stopcocks, other materials may be used as specified. Stopcocks constructed from glass shall be in accordance with Specifications E438 and E671.1.2 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.