{"id":459,"date":"2015-08-05T15:04:00","date_gmt":"2015-08-05T15:04:00","guid":{"rendered":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/uncategorized\/the-flapper-nozzle\/"},"modified":"2015-08-05T15:04:00","modified_gmt":"2015-08-05T15:04:00","slug":"the-flapper-nozzle","status":"publish","type":"post","link":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/the-flapper-nozzle\/","title":{"rendered":"The flapper-nozzle."},"content":{"rendered":"<div class=\"eqzqu6a0dbc79839c0\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '61e5902552e2353963d8d2f1bd1f4a8f',\n\t\t'format' : 'iframe',\n\t\t'height' : 250,\n\t\t'width' : 300,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/61e5902552e2353963d8d2f1bd1f4a8f\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.eqzqu6a0dbc79839c0 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.eqzqu6a0dbc79839c0 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.eqzqu6a0dbc79839c0 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.eqzqu6a0dbc79839c0 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.eqzqu6a0dbc79839c0 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<p align=\"justify\"><b>The flapper-nozzle<\/b> <\/p>\n<p align=\"justify\">Most properties (eg flow, pressure, level, error, desired valve position) can be converted to a small movement. The heart of all pneu&shy;matic process control devices is a device to convert a small displacement into a pressure change, which represents the property causing the displacement. This is invariably based on the flapper&shy; nozzle, whose arrangement, characteristic and application are illus&shy;trated in Figure 7.3. <\/p>\n<p align=\"justify\">An air supply (typically, 2 to 4 bar) is applied to a very fine nozzle via a restriction as shown in Figure 7.3a. The signal output side of the nozzle feeds to a closed (non-venting) load, such as an indicator. Air escapes as a fine jet from the nozzle, so the pressure at A is lower than the supply pressure because of the pressure drop across the restriction. <\/p>\n<p align=\"justify\"><a href=\"http:\/\/lh3.googleusercontent.com\/-UdjOU4VlptE\/VcIl4jYlgBI\/AAAAAAABz1Y\/cH_UL9m75cQ\/s1600-h\/Process%252520control%252520pneumatics-0190%25255B2%25255D.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-bottom: 0px; border-left: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top: 0px; border-right: 0px; padding-top: 0px\" title=\"Process control pneumatics-0190\" border=\"0\" alt=\"Process control pneumatics-0190\" src=\"http:\/\/lh3.googleusercontent.com\/-r_Geqi9-K3Y\/VcIl6kUZ34I\/AAAAAAABz1g\/GlFGLgDcszQ\/Process%252520control%252520pneumatics-0190_thumb.jpg?imgmax=800\" width=\"224\" height=\"244\" \/><\/a> <\/p><div class=\"kxjhn6a0dbc7983b7f\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '0c1eb4c533eaedb7b996f49a5a4983a9',\n\t\t'format' : 'iframe',\n\t\t'height' : 300,\n\t\t'width' : 160,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/0c1eb4c533eaedb7b996f49a5a4983a9\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.kxjhn6a0dbc7983b7f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.kxjhn6a0dbc7983b7f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.kxjhn6a0dbc7983b7f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.kxjhn6a0dbc7983b7f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.kxjhn6a0dbc7983b7f {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<div class=\"kqczi6a0dbc7983a9d\" ><script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-0778475562755157\"\n     crossorigin=\"anonymous\"><\/script>\n<!-- 300x600 hydraulics-and-pneumatics -->\n<ins class=\"adsbygoogle\"\n     style=\"display:inline-block;width:300px;height:600px\"\n     data-ad-client=\"ca-pub-0778475562755157\"\n     data-ad-slot=\"3735577695\"><\/ins>\n<script>\n     (adsbygoogle = window.adsbygoogle || []).push({});\n<\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.kqczi6a0dbc7983a9d {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.kqczi6a0dbc7983a9d {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.kqczi6a0dbc7983a9d {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.kqczi6a0dbc7983a9d {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.kqczi6a0dbc7983a9d {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n\n<p align=\"justify\">Air loss from the jet (and hence pressure at A) is influenced by the gap x between the nozzle and movable flapper; the smaller the gap, the lower the air flow and higher the pressure. A typical response is shown in Figure 7.3b, illustrating the very small range of displacement and the overall non-linear response. The response can, however, be considered linear over a limited range (as shown) and the flapper-nozzle is generally linearised by use of a force balance system as described later. <\/p>\n<p align=\"justify\">Figure 7.3c shows a very simple differential pressure transducer which may be used as a flow transmitter by measuring the pressure drops across an orifice plate. The difference in pressure between P1 and P2 causes a force on the flapper. Assuming P1&gt;P2 (which is true for the direction of flow shown), the top of the flapper is pushed to  <\/p>\n<p align=\"justify\">the right until the force from (P1-P2) is matched by the force from the spring extension. Flapper nozzle gap, and hence the output pressure, is thus determined by the differential pressure and the flow through the orifice plate. <\/p>\n<p align=\"justify\">The arrangement of Figure 7.3c is non-linear, and incapable of maintaining output pressure to a load with even a small loss of air. Even with a totally sealed load the minimal air flow through the restriction leads to a first order lag response with a very long time constant. A flapper-nozzle is therefore usually combined with an air amplifier, or volume booster, which takes a pressure as the input and gives a linearly-related pressure output &#8211; with an ability to supply a large volume of air. When combined with the force balance principle described later, the inherent non-linearity of the flapper nozzle can be overcome.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The flapper-nozzle Most properties (eg flow, pressure, level, error, desired valve position) can be converted to a small movement. The heart of all pneu&shy;matic process control devices is a device to convert a small displacement into a pressure change, which represents the property causing the displacement. This is invariably based on the flapper&shy; nozzle, whose [&hellip;]<br \/><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/the-flapper-nozzle\/\" class=\"more-link\" >Continue reading&#8230;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/posts\/459"}],"collection":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/comments?post=459"}],"version-history":[{"count":0,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/posts\/459\/revisions"}],"wp:attachment":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/media?parent=459"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/categories?post=459"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/tags?post=459"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}