{"id":620212,"date":"2024-11-05T23:38:15","date_gmt":"2024-11-05T23:38:15","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/iso-6145-72018\/"},"modified":"2024-11-05T23:38:15","modified_gmt":"2024-11-05T23:38:15","slug":"iso-6145-72018","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/iso\/iso-6145-72018\/","title":{"rendered":"ISO 6145-7:2018"},"content":{"rendered":"<p>ISO 6145 is a series of documents dealing with various dynamic methods used for the preparation of calibration gas mixtures. This document specifies a method for continuous preparation of calibration gas mixtures, from nominally pure gases or gas mixtures by use of thermal mass-flow controllers. The method is applicable to preparation of mixtures of non-reacting species, i.e. those which do not react with any material of construction of the flow path in the thermal mass-flow controller or the ancillary equipment.<\/p>\n<p>If this method is employed for preparation of calibration gas mixtures the optimum performance is as follows: the relative expanded measurement uncertainty <i>U<\/i>, obtained by multiplying the standard uncertainty by a coverage factor <i>k<\/i> = 2, is not greater than 2 %.<\/p>\n<p>If pre-mixed gases are used instead of pure gases, mole fractions below 10<sup>-6<\/sup> can be obtained. The measurement of mass flow is not absolute and the flow controller requires independent calibration.<\/p>\n<p>The merits of the method are that a large quantity of the calibration gas mixture can be prepared on a continuous basis and that multi-component mixtures can be prepared as readily as binary mixtures if the appropriate number of thermal mass-flow controllers is utilized.<\/p>\n<p>NOTE       Gas blending systems, based upon thermal mass-flow controllers, and some including the facility of computerization and automatic control, are commercially available.<\/p>\n","protected":false},"excerpt":{"rendered":"<p><b>Gas analysis \u2014 Preparation of calibration gas mixtures using dynamic methods \u2014 Part 7: Thermal mass-flow controllers<\/b><\/p>\n<table style=\"width: 100%\" border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td>Published By<\/td>\n<td>Publication Date<\/td>\n<td>Number of Pages<\/td>\n<\/tr>\n<tr>\n<td><a href=\"https:\/\/pdfstandards.shop\/product-category\/publishers\/iso\/\"><b>ISO<\/b><\/a><\/td>\n<td>2018-12<\/td>\n<td>20<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":620227,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[1000,2634],"product_tag":[],"class_list":{"0":"post-620212","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-71-040-40","7":"product_cat-iso","9":"first","10":"instock","11":"sold-individually","12":"shipping-taxable","13":"purchasable","14":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/620212","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/620227"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=620212"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=620212"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=620212"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}