{"id":17253,"date":"2022-11-08T15:10:23","date_gmt":"2022-11-08T14:10:23","guid":{"rendered":"https:\/\/www.ness.de\/?p=17253"},"modified":"2022-11-08T15:14:16","modified_gmt":"2022-11-08T14:14:16","slug":"avoidance-of-excessive-pressure-rises","status":"publish","type":"post","link":"https:\/\/ness.de\/en\/2022\/11\/08\/avoidance-of-excessive-pressure-rises\/","title":{"rendered":"Avoidance of excessive pressure rises of trapped thermal oil or water in pipelines"},"content":{"rendered":"\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-vktadn-26fd2059ab497e4ccdcc7f68c88144f8\">\n.flex_column.av-vktadn-26fd2059ab497e4ccdcc7f68c88144f8{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-vktadn-26fd2059ab497e4ccdcc7f68c88144f8 av_one_full  avia-builder-el-0  el_before_av_one_half  avia-builder-el-first  first flex_column_div av-zero-column-padding  '     ><section  class='av_textblock_section av-k9cer3aa-25b005807f71f2b92d12e5e22aee906d '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h1>Avoidance of excessive pressure rises of trapped thermal oil or water in pipelines<\/h1>\n<\/div><\/section><br \/>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-k9cew20y-73b426f9d452b2e4f0850bc59af7feb1\">\n.avia-image-container.av-k9cew20y-73b426f9d452b2e4f0850bc59af7feb1 img.avia_image{\nbox-shadow:none;\n}\n.avia-image-container.av-k9cew20y-73b426f9d452b2e4f0850bc59af7feb1 .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<div  class='avia-image-container av-k9cew20y-73b426f9d452b2e4f0850bc59af7feb1 av-styling- avia-align-center  avia-builder-el-2  el_after_av_textblock  el_before_av_hr '   itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\" ><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class='wp-image-17263 avia-img-lazy-loading-not-17263 avia_image ' src=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/slider-Eingeschlossenes-thermaloel-1030x328.jpg\" alt='' title='slider-Eingeschlossenes-thermaloel'  height=\"328\" width=\"1030\"  itemprop=\"thumbnailUrl\" srcset=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/slider-Eingeschlossenes-thermaloel-1030x328.jpg 1030w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/slider-Eingeschlossenes-thermaloel-300x95.jpg 300w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/slider-Eingeschlossenes-thermaloel-768x244.jpg 768w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/slider-Eingeschlossenes-thermaloel-1536x489.jpg 1536w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/slider-Eingeschlossenes-thermaloel-2048x652.jpg 2048w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/slider-Eingeschlossenes-thermaloel-1500x477.jpg 1500w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/slider-Eingeschlossenes-thermaloel-705x224.jpg 705w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/slider-Eingeschlossenes-thermaloel-1320x420.jpg 1320w\" sizes=\"(max-width: 1030px) 100vw, 1030px\" \/><\/div><\/div><\/div><br \/>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-k9cf9pjr-684b10e07a089a30a62590e0cf8d2244\">\n#top .hr.hr-invisible.av-k9cf9pjr-684b10e07a089a30a62590e0cf8d2244{\nheight:15px;\n}\n<\/style>\n<div  class='hr av-k9cf9pjr-684b10e07a089a30a62590e0cf8d2244 hr-invisible  avia-builder-el-3  el_after_av_image  el_before_av_textblock '><span class='hr-inner '><span class=\"hr-inner-style\"><\/span><\/span><\/div><br \/>\n<section  class='av_textblock_section av-k9ceof5r-7c3f497f3aa6ddd72ba0c8a48bfbbe5b '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>If thermal oil or water is trapped in pipe ends or pipelines &#8211; e.g. during maintenance work &#8211; and heated therein, it expands greatly and leads to a massive pressure increase in the affected area. The heating of the enclosed liquid can take place due to various external influences, e.g. heat conduction of hot medium from plant areas nearby, solar radiation or heating due to an external fire. <\/p>\n<p>The resulting increase in pressure can cause damage to fittings as well as pipelines and, in the worst case, lead to a leakage of thermal oil or hot water.<\/p>\n<p>The effect of heating by thermal conduction occurs mainly when the associated pipe section is insulated and thus no cooling by thermal conduction and\/or heat radiation to the environment can take place.<\/p>\n<\/div><\/section><br \/>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-5xsrpb8-130e16df620c285051ee60a54f771d34\">\n#top .hr.hr-invisible.av-5xsrpb8-130e16df620c285051ee60a54f771d34{\nheight:15px;\n}\n<\/style>\n<div  class='hr av-5xsrpb8-130e16df620c285051ee60a54f771d34 hr-invisible  avia-builder-el-5  el_after_av_textblock  el_before_av_textblock '><span class='hr-inner '><span class=\"hr-inner-style\"><\/span><\/span><\/div><br \/>\n<section  class='av_textblock_section av-la87dgh1-00a79469ee304be072bdab88f0f43b62 '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h2>Theory<\/h2>\n<\/div><\/section><br \/>\n<section  class='av_textblock_section av-la87he5a-b429448f083b118b7f29161aa71282ff '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>In order to find a measure for a pressure increase, we now take a closer look at a filled pipeline. The calculation below describes this pressure rise for the thermal oil type <em>Mobiltherm 603<\/em> as an example:<\/p>\n<\/div><\/section><br \/>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-k9cf9pjr-3-f31e0bdc62864951f40f993320b17f92\">\n#top .hr.hr-invisible.av-k9cf9pjr-3-f31e0bdc62864951f40f993320b17f92{\nheight:15px;\n}\n<\/style>\n<div  class='hr av-k9cf9pjr-3-f31e0bdc62864951f40f993320b17f92 hr-invisible  avia-builder-el-8  el_after_av_textblock  el_before_av_image '><span class='hr-inner '><span class=\"hr-inner-style\"><\/span><\/span><\/div><br \/>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-w5ybr8-87090edc65173bfa975211b49ad201dd\">\n.avia-image-container.av-w5ybr8-87090edc65173bfa975211b49ad201dd img.avia_image{\nbox-shadow:none;\n}\n.avia-image-container.av-w5ybr8-87090edc65173bfa975211b49ad201dd .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<div  class='avia-image-container av-w5ybr8-87090edc65173bfa975211b49ad201dd av-styling- avia-align-center  avia-builder-el-9  el_after_av_hr  el_before_av_hr '   itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\" ><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class='wp-image-17347 avia-img-lazy-loading-not-17347 avia_image ' src=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/Beispiel-druckanstieg-en-1030x328.jpg\" alt='' title='Beispiel-druckanstieg-en'  height=\"328\" width=\"1030\"  itemprop=\"thumbnailUrl\" srcset=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/Beispiel-druckanstieg-en-1030x328.jpg 1030w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/Beispiel-druckanstieg-en-300x95.jpg 300w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/Beispiel-druckanstieg-en-768x244.jpg 768w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/Beispiel-druckanstieg-en-1536x489.jpg 1536w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/Beispiel-druckanstieg-en-2048x652.jpg 2048w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/Beispiel-druckanstieg-en-1500x477.jpg 1500w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/Beispiel-druckanstieg-en-705x224.jpg 705w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/Beispiel-druckanstieg-en-1320x420.jpg 1320w\" sizes=\"(max-width: 1030px) 100vw, 1030px\" \/><\/div><\/div><\/div><br \/>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-k9cf9pjr-2-12f0c028306f586cfa1acd9ee98c57ba\">\n#top .hr.hr-invisible.av-k9cf9pjr-2-12f0c028306f586cfa1acd9ee98c57ba{\nheight:15px;\n}\n<\/style>\n<div  class='hr av-k9cf9pjr-2-12f0c028306f586cfa1acd9ee98c57ba hr-invisible  avia-builder-el-10  el_after_av_image  el_before_av_textblock '><span class='hr-inner '><span class=\"hr-inner-style\"><\/span><\/span><\/div><br \/>\n<section  class='av_textblock_section av-k9chcuww-be14312cef66e34693ea55efc91af84d '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p><strong>Conclusion<\/strong>: With a completely filled pipeline, there is a pressure increase of approx. 6 bar per 1 K temperature increase for <em>Mobiltherm 603<\/em>.<\/p>\n<p>In general, the value for the coefficient of volume expansion for thermal oils varies between the values 0.00065 and 0.00095 1\/K. Thus, depending on the type of thermal oil, the pressure increase can be between 6 and 10 bar per Kelvin temperature increase. For water at 90\u00b0C, the coefficient of volume expansion is 0.000696 1\/K and is thus in the same magnitude.<\/p>\n<\/div><\/section><br \/>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-5f6urfo-e9dd5bdf1433e6d56887fa4c4a98f1ce\">\n#top .hr.hr-invisible.av-5f6urfo-e9dd5bdf1433e6d56887fa4c4a98f1ce{\nheight:15px;\n}\n<\/style>\n<div  class='hr av-5f6urfo-e9dd5bdf1433e6d56887fa4c4a98f1ce hr-invisible  avia-builder-el-12  el_after_av_textblock  el_before_av_textblock '><span class='hr-inner '><span class=\"hr-inner-style\"><\/span><\/span><\/div><br \/>\n<section  class='av_textblock_section av-la87ssgh-8a545c538d33c98ffadc74f88109ad76 '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h2>Effects<\/h2>\n<\/div><\/section><br \/>\n<section  class='av_textblock_section av-la87tuh1-11bbf2af1d141a014b33f021fbeb0e0a '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>Depending on the design of the affected area, the effects are different. If the closing pressure of the valve is lower than the failure pressure of the seal and the pressure rise is located before the seat of the stop valve, the poppet is pressed into the actuator. As a result, only an undefined opening of the valve occurs and medium as well as pressure can be exchanged between the two areas.<\/p>\n<p>The situation is different if the pressure increase occurs behind the seat of a stop valve or the closing pressure of the valve is greater than the failure pressure of the seal. In this case, the pressure cannot escape, so massive damage can occur to the valve or another component in the section with the high pressure.<\/p>\n<p>Due to the high pressure behind the valve seat, the sealing surface, which separates the medium from the actuator area, is pressed against the housing. In addition, a change can be seen on the bellows. Elastic as well as plastic deformations occur at the valve. After failure of the graphite seal, thermal oil escapes from the separated area, causing the pressure there to decrease and the elastic deformation to return. The plastic deformation at the valve remains and opens it partially. This creates a connection from the main system to the environment, which can result in a major leakage.<\/p>\n<\/div><\/section><\/p><\/div><div  class='flex_column av-4oxxp8k-b73f0695609f916d241745eb67dc2c81 av_one_half  avia-builder-el-15  el_after_av_one_full  el_before_av_one_half  first flex_column_div  column-top-margin'     ><p>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-4j1kdr8-8802a945bffcb46be891266b23346c66\">\n@keyframes av_boxShadowEffect_av-4j1kdr8-8802a945bffcb46be891266b23346c66 {\n0%   { box-shadow:  0 0 0 0 ; opacity: 1; }\n100% { box-shadow:  0 0 10px 0 ; opacity: 1; }\n}\n.avia-image-container.av-4j1kdr8-8802a945bffcb46be891266b23346c66 img.avia_image{\nbox-shadow: 0 0 10px 0 ;\n}\n.avia-image-container.av-4j1kdr8-8802a945bffcb46be891266b23346c66 .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<div  class='avia-image-container av-4j1kdr8-8802a945bffcb46be891266b23346c66 av-styling- avia-align-center  avia-builder-el-16  el_before_av_textblock  avia-builder-el-first  av-img-box-shadow av-box-shadow-not-animated'   itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\" ><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class='wp-image-17284 avia-img-lazy-loading-not-17284 avia_image shadow-not-animated' src=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/beschaedigtes-ventil.jpg\" alt='' title='beschaedigtes-ventil'  height=\"500\" width=\"500\"  itemprop=\"thumbnailUrl\" srcset=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/beschaedigtes-ventil.jpg 500w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/beschaedigtes-ventil-300x300.jpg 300w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/beschaedigtes-ventil-80x80.jpg 80w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/beschaedigtes-ventil-36x36.jpg 36w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/beschaedigtes-ventil-180x180.jpg 180w\" sizes=\"(max-width: 500px) 100vw, 500px\" \/><\/div><\/div><\/div><br \/>\n<section  class='av_textblock_section av-la88ffaa-e71bcd97da695e5e0533dbf6362a2fd5 '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h6><em>Damaged angle seat valve<\/em><\/h6>\n<\/div><\/section><\/p><\/div><\/p>\n<div  class='flex_column av-44pjzr8-4b52ea162113fdac6c198ad9f29e2e17 av_one_half  avia-builder-el-18  el_after_av_one_half  el_before_av_one_full  flex_column_div  column-top-margin'     ><p>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-la88e0d4-b3f824272f5e3d56a49704251a616e10\">\n@keyframes av_boxShadowEffect_av-la88e0d4-b3f824272f5e3d56a49704251a616e10 {\n0%   { box-shadow:  0 0 0 0 ; opacity: 1; }\n100% { box-shadow:  0 0 10px 0 ; opacity: 1; }\n}\n.avia-image-container.av-la88e0d4-b3f824272f5e3d56a49704251a616e10 img.avia_image{\nbox-shadow: 0 0 10px 0 ;\n}\n.avia-image-container.av-la88e0d4-b3f824272f5e3d56a49704251a616e10 .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<div  class='avia-image-container av-la88e0d4-b3f824272f5e3d56a49704251a616e10 av-styling- avia-align-center  avia-builder-el-19  el_before_av_textblock  avia-builder-el-first  av-img-box-shadow av-box-shadow-not-animated'   itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\" ><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class='wp-image-17288 avia-img-lazy-loading-not-17288 avia_image shadow-not-animated' src=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/unbeschaedigtes-ventil.jpg\" alt='' title='unbeschaedigtes-ventil'  height=\"500\" width=\"500\"  itemprop=\"thumbnailUrl\" srcset=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/unbeschaedigtes-ventil.jpg 500w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/unbeschaedigtes-ventil-300x300.jpg 300w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/unbeschaedigtes-ventil-80x80.jpg 80w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/unbeschaedigtes-ventil-36x36.jpg 36w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/unbeschaedigtes-ventil-180x180.jpg 180w\" sizes=\"(max-width: 500px) 100vw, 500px\" \/><\/div><\/div><\/div><br \/>\n<section  class='av_textblock_section av-la88fvik-514791795dbd376d93025da94348905e '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h6><em>Intact angle seat valve<\/em><\/h6>\n<\/div><\/section><\/p><\/div>\n<div  class='flex_column av-bsgah0-1915b992d3db7d8908c227d3314307c6 av_one_full  avia-builder-el-21  el_after_av_one_half  el_before_av_one_half  first flex_column_div  column-top-margin'     ><section  class='av_textblock_section av-la88gwfk-1cf79f03d68be66a09f96596e5a80ca4 '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h2>Recommendations for action<\/h2>\n<\/div><\/section><br \/>\n<section  class='av_textblock_section av-la88hl6w-51b4799a03f48f834936e6280b9e7f8c '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>The following is required for safe operation of the systems:<\/p>\n<ul>\n<li>In case of a valve shuts off a closed pipeline end (welded cap or blind flange), it must be open during operation. It is recommended to secure these valves in their correct position, e.g. with a plastic safety device.<\/li>\n<li>In case of the valve cannot be opened at a pipeline end, the pipeline end after the valve must not be insulated and it must not be completely filled with liquid. There must be a gas cushion.<\/li>\n<li>In case of two valves are installed one behind the other in a pipe section and both must be closed for safety reasons (&#8220;double block&#8221;), we recommend installing a test and drain valve in the intermediate space. This allows to empty the space in between, fill the pipe section with air, and prevent excessive pressure buildup by the compressible medium.<\/li>\n<li>In case of two valves are installed one after the other in drain pipes, care must be taken to ensure the correct closing sequence.<\/li>\n<\/ul>\n<p>The actions above are of particular importance when valves and nozzles are insulated.<\/p>\n<p>Service interventions (e.g. maintenance) or temporarily closed quick-closing flaps due to safety circuits can lead to temporary trapping of thermal oil. Here, care must be taken to ensure that these conditions are kept as short as possible in order to avoid pressure increases or vacuum. In addition, pressure monitoring or other actions are recommended.<\/p>\n<\/div><\/section><br \/>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-33a5wmc-78f6b280306a7fb5188539cd9171dc6b\">\n#top .hr.hr-invisible.av-33a5wmc-78f6b280306a7fb5188539cd9171dc6b{\nheight:15px;\n}\n<\/style>\n<div  class='hr av-33a5wmc-78f6b280306a7fb5188539cd9171dc6b hr-invisible  avia-builder-el-24  el_after_av_textblock  el_before_av_textblock '><span class='hr-inner '><span class=\"hr-inner-style\"><\/span><\/span><\/div><br \/>\n<section  class='av_textblock_section av-la88i6jg-9ad321db6f9b19e1514e61a452ec7a1f '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h2>Example: Reserve connection with welding pipe cap or blind flange<\/h2>\n<\/div><\/section><br \/>\n<section  class='av_textblock_section av-la88m7pj-2407ed22167d7f900cd25933c958dc40 '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>This is implemented, for example, at unused connections of manifolds or to connect temporarily used equipment to the overall system. <\/p>\n<p>As the welded pipe cap and the flange-soft seal-blind flange connection are considered to be technically tight, we recommend that the valve is always left open during normal operation. The test and drain valve must be closed during operation.<\/p>\n<\/div><\/section><\/p><\/div>\n<div  class='flex_column av-2oijykk-450f7e9e2a1203693ef4663f0dcf637e av_one_half  avia-builder-el-27  el_after_av_one_full  el_before_av_one_half  first flex_column_div  column-top-margin'     ><p>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-la88qik9-497b81f09285fe38b70a74bd2f7121f9\">\n@keyframes av_boxShadowEffect_av-la88qik9-497b81f09285fe38b70a74bd2f7121f9 {\n0%   { box-shadow:  0 0 0 0 ; opacity: 1; }\n100% { box-shadow:  0 0 10px 0 ; opacity: 1; }\n}\n.avia-image-container.av-la88qik9-497b81f09285fe38b70a74bd2f7121f9 img.avia_image{\nbox-shadow: 0 0 10px 0 ;\n}\n.avia-image-container.av-la88qik9-497b81f09285fe38b70a74bd2f7121f9 .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<div  class='avia-image-container av-la88qik9-497b81f09285fe38b70a74bd2f7121f9 av-styling- avia-align-center  avia-builder-el-28  el_before_av_textblock  avia-builder-el-first  av-img-box-shadow av-box-shadow-not-animated'   itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\" ><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class='wp-image-17300 avia-img-lazy-loading-not-17300 avia_image shadow-not-animated' src=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-rohrkappe.jpg\" alt='' title='reserveanschluss-rohrkappe'  height=\"500\" width=\"500\"  itemprop=\"thumbnailUrl\" srcset=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-rohrkappe.jpg 500w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-rohrkappe-300x300.jpg 300w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-rohrkappe-80x80.jpg 80w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-rohrkappe-36x36.jpg 36w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-rohrkappe-180x180.jpg 180w\" sizes=\"(max-width: 500px) 100vw, 500px\" \/><\/div><\/div><\/div><br \/>\n<section  class='av_textblock_section av-la88qsi2-0dd082851d66b21de112dbf53646684b '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h6><em>Reserve connection with weld-on cap<br \/>\n<\/em><\/h6>\n<\/div><\/section><\/p><\/div>\n<div  class='flex_column av-1xmnkf8-925a55b6b63bd9784aca5d281c71e01a av_one_half  avia-builder-el-30  el_after_av_one_half  el_before_av_one_full  flex_column_div  column-top-margin'     ><p>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-la88r4zf-967cc8b98f4def22e5f965aa296aec76\">\n@keyframes av_boxShadowEffect_av-la88r4zf-967cc8b98f4def22e5f965aa296aec76 {\n0%   { box-shadow:  0 0 0 0 ; opacity: 1; }\n100% { box-shadow:  0 0 10px 0 ; opacity: 1; }\n}\n.avia-image-container.av-la88r4zf-967cc8b98f4def22e5f965aa296aec76 img.avia_image{\nbox-shadow: 0 0 10px 0 ;\n}\n.avia-image-container.av-la88r4zf-967cc8b98f4def22e5f965aa296aec76 .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<div  class='avia-image-container av-la88r4zf-967cc8b98f4def22e5f965aa296aec76 av-styling- avia-align-center  avia-builder-el-31  el_before_av_textblock  avia-builder-el-first  av-img-box-shadow av-box-shadow-not-animated'   itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\" ><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class='wp-image-17304 avia-img-lazy-loading-not-17304 avia_image shadow-not-animated' src=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-blindflansch.jpg\" alt='' title='reserveanschluss-blindflansch'  height=\"500\" width=\"500\"  itemprop=\"thumbnailUrl\" srcset=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-blindflansch.jpg 500w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-blindflansch-300x300.jpg 300w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-blindflansch-80x80.jpg 80w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-blindflansch-36x36.jpg 36w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/reserveanschluss-blindflansch-180x180.jpg 180w\" sizes=\"(max-width: 500px) 100vw, 500px\" \/><\/div><\/div><\/div><br \/>\n<section  class='av_textblock_section av-la88rtj5-74f463374d99e8cf1e61a72af8e403ca '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h6><em>Reserve connection with blind flange<\/em><\/h6>\n<h6><em>\u00a0<\/em><\/h6>\n<\/div><\/section><\/p><\/div>\n<div  class='flex_column av-1i23ydg-abab7e73f17599955fcaa249a83bb6ff av_one_full  avia-builder-el-33  el_after_av_one_half  el_before_av_one_third  first flex_column_div  column-top-margin'     ><section  class='av_textblock_section av-la88tedc-5ad5b8a9f3dfc4630e4601a98747a18c '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h2>Example: Two valves one after the other in the piping system<\/h2>\n<\/div><\/section><br \/>\n<section  class='av_textblock_section av-la88wkan-3989a60cd96b5bb932cff646986e759a '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>For safety reasons, two valves are installed in series in the piping system, called &#8220;double block&#8221;.<\/p>\n<p>This application as an example for the connection of the entire system to an expansion tank. In the event that the expansion tank has to be disconnected from the system, both shut-off valves must always be closed. This is necessary because redundancy and the associated safety have the highest priority.<\/p>\n<p>To avoid trapping thermal oil between the two shut-off devices, a test and drain valve must be installed between them. This allows to empty the space in between, fill the pipe section with air, and prevent excessive pressure buildup by the compressible medium.<\/p>\n<\/div><\/section><\/p><\/div>\n<div  class='flex_column av-177jlj8-1d7a67e693da09ab1601956b3626e470 av_one_third  avia-builder-el-36  el_after_av_one_full  el_before_av_one_full  first flex_column_div  column-top-margin'     ><p>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-la890wex-4ed47b3acf1917f201caeb308ccc249f\">\n@keyframes av_boxShadowEffect_av-la890wex-4ed47b3acf1917f201caeb308ccc249f {\n0%   { box-shadow:  0 0 0 0 ; opacity: 1; }\n100% { box-shadow:  0 0 10px 0 ; opacity: 1; }\n}\n.avia-image-container.av-la890wex-4ed47b3acf1917f201caeb308ccc249f img.avia_image{\nbox-shadow: 0 0 10px 0 ;\n}\n.avia-image-container.av-la890wex-4ed47b3acf1917f201caeb308ccc249f .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<div  class='avia-image-container av-la890wex-4ed47b3acf1917f201caeb308ccc249f av-styling- avia-align-center  avia-builder-el-37  el_before_av_textblock  avia-builder-el-first  av-img-box-shadow av-box-shadow-not-animated'   itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\" ><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class='wp-image-17311 avia-img-lazy-loading-not-17311 avia_image shadow-not-animated' src=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/anbindung-ausdehnungsgefaess.jpg\" alt='' title='anbindung-ausdehnungsgefaess'  height=\"500\" width=\"250\"  itemprop=\"thumbnailUrl\" srcset=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/anbindung-ausdehnungsgefaess.jpg 250w, https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/anbindung-ausdehnungsgefaess-150x300.jpg 150w\" sizes=\"(max-width: 250px) 100vw, 250px\" \/><\/div><\/div><\/div><br \/>\n<section  class='av_textblock_section av-la891649-a44cd78835b5e8ae345efab09ffc3acf '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h6><em>Connection to the expansion tank<br \/>\n<\/em><\/h6>\n<\/div><\/section><\/p><\/div>\n<div  class='flex_column av-s1pe4k-d0888cf3dd5a5569f7546b5e24982551 av_one_full  avia-builder-el-39  el_after_av_one_third  avia-builder-el-last  first flex_column_div  column-top-margin'     ><section  class='av_textblock_section av-la892erg-0da22d6b7ca9c8fea203f14e7085d4e1 '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h2>Example: Two valves one after the other with open line end<\/h2>\n<\/div><\/section><br \/>\n<section  class='av_textblock_section av-la893t6y-9c4dd4e6ebcd1baf838a3ec4868f929f '   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>This case occurs, for example, at tank emptying. To prevent trapping of thermal oil, attention must be paid to the sequence when closing the valves: The shut-off valve that is closer to the medium must be closed first. Only if no more thermal oil flows out of the open end of the line may the second, outer valve be closed.<\/p>\n<\/div><\/section><\/p><\/div>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":3,"featured_media":17263,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23,18],"tags":[],"class_list":["post-17253","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-ness-news-en","category-ness-news"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.9 (Yoast SEO v27.9) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Avoidance of excessive pressure rises of trapped thermal oil or water in pipelines<\/title>\n<meta name=\"description\" content=\"Excessive pressure rises of trapped thermal oil or water in pipelines - avoidance strategies and examples from practice\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/ness.de\/en\/2022\/11\/08\/avoidance-of-excessive-pressure-rises\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Avoidance of excessive pressure rises of trapped thermal oil or water in pipelines\" \/>\n<meta property=\"og:description\" content=\"Excessive pressure rises of trapped thermal oil or water in pipelines - avoidance strategies and examples from practice\" \/>\n<meta property=\"og:url\" content=\"https:\/\/ness.de\/en\/2022\/11\/08\/avoidance-of-excessive-pressure-rises\/\" \/>\n<meta property=\"og:site_name\" content=\"NESS W\u00e4rmetechnik\" \/>\n<meta property=\"article:published_time\" content=\"2022-11-08T14:10:23+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2022-11-08T14:14:16+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/ness.de\/wp-content\/uploads\/2022\/11\/slider-Eingeschlossenes-thermaloel.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"2200\" \/>\n\t<meta property=\"og:image:height\" content=\"700\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"J. 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