DOP\/PAO High-Efficiency Filter Leak Detection Principle (Full Version)
\nI. Core Sentence
\nInject aerosol towards the upstream, measure the leakage concentration at the downstream, and determine the integrity of the filter and seal by the “penetration rate”.
\nII. Detailed Principle (GMP\/ISO Standard Explanation)
\n1. What is DOP\/PAO
\nDOP: Di-Isopropyl Phthalate, an early used aerosol
\nPAO: Poly \u03b1-Ether, the current mainstream, safe, and recommended
\nBoth are oily aerosols, capable of generating challenge particles of about 0.3\u03bcm \u2014
\nThis is precisely the particle size that is most difficult for HEPA filters to filter and most prone to leakage.
\n2. Leak Detection Physical Principle: Challenge upstream + Scan downstream
\n1) In the upstream, create a stable concentration of aerosol to heat or cool it and send it into the filter intake side (upstream). Form a uniform and stable challenge concentration C\u2080.
\n2) The normal filtration principle of HEPA: HEPA filters have a filtration efficiency of \u2265 99.97% for 0.3\u03bcm particles. Under normal circumstances:
\nUpstream: There is aerosol
\nDownstream: Almost undetectable
\n3) Leakage = Aerosol “circles around” the filter. If any of the following occurs:
\nFilter paper damage
\nPinholes
\nBorder seal not tight
\nInstallation gap
\nRubber strip aging
\nThe aerosol will directly leak to the downstream without passing through the filter, and the photometer will immediately read the number skyrocketing.
\nIII. What is Measured by the Photometer?
\nIt measures: Downstream concentration \/ Upstream concentration \u00d7 100% which is the penetration rate (% Leakage)
\nQualified Judgment Principle (GMP General)
\nNormal and intact filter:
\nPenetration rate \u2264 0.01%
\nOnce > 0.01%
\n\u2192 Judged as leakage
\nIV. Analogical Explanation (Convenient for Training)
\nYou can understand it this way:
\nHigh-efficiency filter = A super-precise sieve
\nDOP\/PAO particles = Fine sand
\nUpstream = Continuously spreading fine sand
\nDownstream = Use a detector to find out if any sand leaks over
\nNormal sieve: Sand is almost completely blocked, downstream has almost none.
\nLeaked: Sand directly passes through the broken hole \/ gap, the detector immediately alarms.
\nV. Why Must Use DOP\/PAO?
\nBecause:
\nThe particle size of 0.3\u03bcm is the most difficult point for HEPA
\nThe particles are single-distributed, stable, and easy to detect
\nNon-conductive, non-hygroscopic, does not affect production
\nComplies with ISO 14644, GMP, FDA leak detection requirements
\nVI. Summary (Most Concise Version, Can Be Memorized Directly)
\nDOP\/PAO Leak Detection Principle:
\nInject standard aerosol upstream, scan the filter surface and border with a photometer downstream,
\nBy measuring the aerosol penetration rate, determine if the filter paper is damaged and the seal is intact.<\/p>","protected":false},"excerpt":{"rendered":"
DOP\/PAO High-Efficiency Filter Leak Detection Principle (Full Version) I. Core Sentence Inject aerosol towards the upstream, measure the leakage concentration at the downstream, and determine the integrity of the filter and seal by the “penetration rate”. II. Detailed Principle (GMP\/ISO Standard Explanation) 1. What is DOP\/PAO DOP: Di-Isopropyl Phthalate, an early used aerosol PAO: Poly […]<\/p>","protected":false},"author":3,"featured_media":4884,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[92],"tags":[],"class_list":["post-5137","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry-technology"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.bacintl.com\/es\/wp-json\/wp\/v2\/posts\/5137","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bacintl.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bacintl.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bacintl.com\/es\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bacintl.com\/es\/wp-json\/wp\/v2\/comments?post=5137"}],"version-history":[{"count":1,"href":"https:\/\/www.bacintl.com\/es\/wp-json\/wp\/v2\/posts\/5137\/revisions"}],"predecessor-version":[{"id":5138,"href":"https:\/\/www.bacintl.com\/es\/wp-json\/wp\/v2\/posts\/5137\/revisions\/5138"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bacintl.com\/es\/wp-json\/wp\/v2\/media\/4884"}],"wp:attachment":[{"href":"https:\/\/www.bacintl.com\/es\/wp-json\/wp\/v2\/media?parent=5137"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bacintl.com\/es\/wp-json\/wp\/v2\/categories?post=5137"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bacintl.com\/es\/wp-json\/wp\/v2\/tags?post=5137"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}