![\"\"](\"https:\/\/zecovalve.com\/wp-content\/uploads\/2022\/01\/20220105083122-61d5575ae65f4.jpg\")
<\/figure>\n<\/div>\n\n\nComment fonctionne une vanne \u00e0 membrane ?<\/h2>\n\n\n\n
La puissance de fonctionnement d\u2019une vanne \u00e0 membrane peut provenir de diverses sources. Une vanne pneumatique \u00e0 membrane utilise la pression de l\u2019air pour l\u2019ouvrir ou la fermer. Parfois, un sol\u00e9no\u00efde \u2013 un composant m\u00e9tallique envelopp\u00e9 de fil qui peut produire un champ magn\u00e9tique en pr\u00e9sence d\u2019\u00e9lectricit\u00e9 \u2013 est utilis\u00e9 pour actionner la vanne. D\u2019autres fois, il peut \u00eatre actionn\u00e9 manuellement. De plus, la pression hydraulique est \u00e9galement couramment utilis\u00e9e.<\/p>\n\n\n\n
Types de vannes \u00e0 membrane<\/h2>\n\n\n\n- Vannes \u00e0 membrane de type d\u00e9versoir<\/strong>
- La vanne \u00e0 membrane de type d\u00e9versoir est l'une des conceptions les plus courantes disponibles et correspond \u00e0 celle illustr\u00e9e \u00e0 la figure 2 ci-dessus. La conception \u00e0 l\u00e8vre\/selle sur\u00e9lev\u00e9e est la mieux adapt\u00e9e au contr\u00f4le de petit d\u00e9bit et reste \u00e9tanche gr\u00e2ce au chapeau sur le diaphragme et l'actionneur. Cette conception est optimale pour les liquides et gaz dangereux ou corrosifs, car toute d\u00e9faillance de la membrane sera contenue par ce capot. De plus, le corps inclin\u00e9 rend cette vanne intrins\u00e8quement auto-drainante, mais cette vidange peut se produire dans les deux sens de la vanne, ce qui peut ne pas \u00eatre optimal pour certaines applications. La vanne de type d\u00e9versoir est principalement sp\u00e9cifi\u00e9e pour les fluides propres et homog\u00e8nes, car des boues visqueuses et des s\u00e9diments peuvent s'accumuler de chaque c\u00f4t\u00e9 de la selle. On les trouve le plus souvent dans des processus tels que les applications alimentaires\/chimiques, la production de gaz, les applications corrosives et l'eau.<\/li><\/ul><\/li>
- Vannes \u00e0 membrane de type traversant droit<\/strong>
- La vanne \u00e0 membrane directe est structurellement similaire aux types \u00e0 d\u00e9versoir\u00a0; cependant, il ne contient pas la selle caract\u00e9ristique et a plut\u00f4t un chemin compl\u00e8tement droit. Leurs membranes sont g\u00e9n\u00e9ralement plus flexibles et permettent une distance de d\u00e9placement plus longue, car elles doivent toucher tout le bas de la valve. Ces vannes doivent souvent \u00eatre entretenues\/remplac\u00e9es, car leur dur\u00e9e de vie est g\u00e9n\u00e9ralement inf\u00e9rieure \u00e0 celle des conceptions \u00e0 d\u00e9versoir en raison de leurs membranes plus flexibles. Les vannes \u00e0 membrane directe sont utilis\u00e9es pour les boues, les fluides visqueux et d'autres applications o\u00f9 le blocage doit \u00eatre r\u00e9duit. Ils sont \u00e9galement utiles pour les r\u00e9gimes d'\u00e9coulement bidirectionnels, car il n'y a pas de selle pour emp\u00eacher le passage rapide de l'entr\u00e9e \u00e0 la sortie.<\/li><\/ul><\/li><\/ul>\n\n\n\n
Avantages des vannes \u00e0 membrane ?<\/h2>\n\n\n\n- Les vannes \u00e0 membrane peuvent \u00e9galement \u00eatre utilis\u00e9es pour le service d'\u00e9tranglement.<\/li>
- Ses caract\u00e9ristiques d'\u00e9tranglement sont essentiellement celles d'une vanne \u00e0 ouverture rapide en raison de la grande zone d'arr\u00eat le long du si\u00e8ge.<\/li>
- Une vanne \u00e0 membrane de type d\u00e9versoir est disponible pour contr\u00f4ler les petits d\u00e9bits.<\/li>
- Les vannes \u00e0 membrane sont particuli\u00e8rement adapt\u00e9es \u00e0 la manipulation de fluides corrosifs, de boues fibreuses, de fluides radioactifs ou d'autres fluides qui doivent rester exempts de contamination.<\/li>
- Le m\u00e9canisme de fonctionnement d'une vanne \u00e0 membrane n'est pas expos\u00e9 aux fluides pr\u00e9sents dans la canalisation. Les fluides collants ou visqueux ne peuvent pas p\u00e9n\u00e9trer dans le capot et interf\u00e9rer avec le m\u00e9canisme de fonctionnement.<\/li>
- De nombreux fluides susceptibles d'obstruer, de corroder ou de gommer les pi\u00e8ces actives de la plupart des autres types de vannes passeront \u00e0 travers une vanne \u00e0 membrane sans causer de probl\u00e8mes. \u00c0 l\u2019inverse, les lubrifiants utilis\u00e9s pour le m\u00e9canisme de commande ne peuvent pas contaminer le fluide manipul\u00e9.<\/li>
- Il n\u2019y a aucun presse-\u00e9toupe \u00e0 entretenir et aucune possibilit\u00e9 de fuite de tige dans les vannes.<\/li><\/ul>\n\n\n\n\n
Balises associ\u00e9es :<\/h2>\n\n\n\n\n\nSoupape ZECO<\/a>\n\n<\/div>\n\n\n\n\nDiff\u00e9rence entre la vanne \u00e0 vanne et la vanne papillon<\/a>\n\n<\/div>\n\n\n\n\nQue sont les vannes \u00e0 soupape\u00a0?<\/a>\n\n<\/div>\n\n\n\n\nFabricant de robinets-vannes \u00e0 commande manuelle<\/a>\n\n<\/div>\n\n\n\n\nQu'est-ce qu'un robinet-vanne ?<\/a>\n\n<\/div>\n\n\n\n\nUsine de soupapes de r\u00e9duction de pression de Shanghai<\/a>\n\n<\/div>\n\n\n\n\nQue sont les vannes de r\u00e9gulation automatique ?<\/a>\n\n<\/div>\n\n\n\n\nRobinet \u00e0 soupape et robinet \u00e0 bille<\/a>\n\n<\/div>\n\n\n\n\nFournisseur de vannes \u00e0 vanne de 12 pouces<\/a>\n\n<\/div>\n\n\n\n\nMat\u00e9riaux thermoplastiques comme si\u00e8ge de robinet \u00e0 tournant sph\u00e9rique et si\u00e8ge de vanne papillon<\/a>\n\n<\/div>","protected":false},"excerpt":{"rendered":"Dans la plupart des situations, les vannes \u00e0 membrane ne constituent pas une consid\u00e9ration importante. Mais lorsqu\u2019une vanne peut am\u00e9liorer vos performances dans les processus en aval, elle\u2026 Lire plus<\/a><\/p>","protected":false},"author":2,"featured_media":13348,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_generate-full-width-content":"","kt_blocks_editor_width":"","footnotes":""},"categories":[1],"tags":[2702,2704,2703,3205],"class_list":["post-3059","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-diaphragm-valve","tag-diaphragm-valve-diagram","tag-diaphragm-valve-function","tag-diaphragm-valve-manufacturers","generate-columns","tablet-grid-50","mobile-grid-100","grid-parent","grid-50"],"featured_image_src_large":["https:\/\/zecovalve.com\/wp-content\/uploads\/2022\/01\/20220105083122-61d5575ae65f4.jpg",924,1004,false],"author_info":{"display_name":"Jerry","author_link":"https:\/\/zecovalve.com\/fr\/author\/jerry"},"comment_info":0,"category_info":[{"term_id":1,"name":"Uncategorized","slug":"uncategorized","term_group":0,"term_taxonomy_id":1,"taxonomy":"category","description":"","parent":0,"count":452,"filter":"raw","cat_ID":1,"category_count":452,"category_description":"","cat_name":"Uncategorized","category_nicename":"uncategorized","category_parent":0}],"tag_info":[{"term_id":2702,"name":"Diaphragm Valve","slug":"diaphragm-valve","term_group":0,"term_taxonomy_id":2702,"taxonomy":"post_tag","description":"","parent":0,"count":3,"filter":"raw"},{"term_id":2704,"name":"diaphragm valve diagram","slug":"diaphragm-valve-diagram","term_group":0,"term_taxonomy_id":2704,"taxonomy":"post_tag","description":"","parent":0,"count":2,"filter":"raw"},{"term_id":2703,"name":"Diaphragm Valve Function","slug":"diaphragm-valve-function","term_group":0,"term_taxonomy_id":2703,"taxonomy":"post_tag","description":"\r\n\r\n\r\n\r\nGET DIAPHRAGM VALVE DIAGRAM INFORMATION<\/strong><\/a>\r\n\r\n\r\n\r\n\r\nWhat is a Diaphragm Valve?<\/h2>\r\n\r\n\r\n\r\n\r\nDiaphragm valves get their name from a flexible disc that comes into contact with a seat at the top of the valve body to form a seal. A diaphragm is a flexible, pressure-responsive element that transmits force to open, close, or control a valve. Diaphragm valves are related to pinch valves, but use an elastomeric diaphragm, instead of an elastomeric liner in the valve body, to separate the flow stream from the closure element.\r\n\r\n\r\n\r\n\r\n![\"\"](\"https:\/\/zecovalve.com\/wp-content\/uploads\/2022\/07\/20220708083634-62c7ec92aba44.jpg\")
<\/figure>\r\n\r\n\r\n\r\nHow do Diaphragm Valves Work?<\/h2>\r\n\r\n\r\n\r\n\r\nDiaphragm valves are simple in construction and operation. A valve actuator is in contact with the inner membrane (or \u201cdiaphragm\u201d) of the valve in its open position. When the user desires the valve to be shut, the actuator is pressed and\/or turned and the membrane is pushed into the edge of the solid damn, closing the valve. Certain diaphragm valves can also have half open\/restricted positions where the membrane is partially closed, allowing a throttled flow through the valve. In the next section, we will examine the broad categories of diaphragm valves and where they are most useful.\r\n\r\n\r\n\r\n\r\nTypes of Diaphragm Valves<\/h2>\r\n\r\n\r\n\r\nWeir-Type Diaphragm Valves<\/h3>\r\n\r\n\r\n\r\n\r\nThe weir-type diaphragm valve is one of the most common designs available and is what is shown in Figure 2, above. The raised lip\/saddle design is best suited for small flow control and is kept leak-proof thanks to the bonnet over the diaphragm and actuator. This design is optimal for dangerous or corrosive liquid and gas, as any failure with the membrane will be kept contained by this bonnet. Also, the sloped body makes this valve inherently self-draining, but this draining can happen in both valve directions which may not be optimal for some applications. The weir-type valve is mostly specified for clean, homogenous fluids, as viscous slurries and sediments may build up on either side of the saddle. They are most often found in processes such as food\/chemical, gas production, corrosive, and water applications.\r\n\r\n\r\n\r\n\r\nStraight Through Type Diaphragm Valves<\/h3>\r\n\r\n\r\n\r\n\r\nThe straight-through diaphragm valve is structurally similar to weir-types; however, it does not contain the characteristic saddle and instead has a completely straight pathway. Their membranes are typically more flexible and allow for farther travel distance, as it must touch the very bottom of the valve. These valves must often be serviced\/replaced, as their lifespan is typically less than weir-type designs due to their more flexible membranes. Straight-through diaphragm valves are used for slurries, viscous fluids, and other applications where blocking must be reduced. They are also useful for bi-directional flow regimes, as there is no saddle to impede swift changing from inlet to outlet.\r\n\r\n\r\n\r\n\r\nDiaphragm Valve Parts<\/h2>\r\n\r\n\r\n\r\n\r\nThe components of diaphragm valves are the following:\r\n\r\n\r\n\r\n\r\nDiaphragm Valve Bonnet<\/h3>\r\n\r\n\r\n\r\n\r\nThe bonnet serves as the top cover and is bolted to the valve body. It protects the compressor, stem, diaphragm, and other non-wetted components of the diaphragm valve.\r\n\r\n\r\n\r\n\r\nDiaphragm Valve Body<\/h3>\r\n\r\n\r\n\r\n\r\nThe valve body is the component directly connected to the pipeline wherein the fluid passes. The flow area inside the valve body depends on the type of diaphragm valve.\r\n\r\n\r\n\r\n\r\n\r\nBoth the valve body and bonnet are constructed from strong, rigid, and corrosive resistant materials.\r\n\r\n\r\n\r\n\r\nDiaphragm Valve Diaphragm<\/h3>\r\n\r\n\r\n\r\n\r\nThe diaphragm is made from a highly elastic polymeric disc that moves down to touch the bottom of the valve body to limit or obstruct the passage of fluid. The diaphragm lifts if the fluid flow rate is to be increased or the valve is to be fully opened. The fluid flows underneath the diaphragm. However, this component limits the valve\u2019s operating temperature and pressure due to the diaphragm\u2019s material and structure. It must also be replaced periodically since its mechanical properties degrade during usage.\r\n\r\n\r\n\r\n\r\n\r\nThe diaphragm isolates the non-wetted components (compressor, stem, and actuator) from the flowing media. Therefore, solids and viscous fluids are less likely to interfere with the operating mechanism of the diaphragm valve. This also protects the non-wetted components from corrosion. Conversely, the fluid in the pipeline will not be contaminated with the lubricant used in operating the valve.\r\n\r\n\r\n\r\n\r\nMaterial of Diaphragm Valve Diaphragm<\/h4>\r\n\r\n\r\n\r\n\r\nUnlined or Rubber Lined Type<\/strong>\r\n\r\n\r\n\r\n\r\n\r\n \t- NR\/Natural Rubber<\/li>\r\n \t
- NBR\/Nitrile\/Buna-N<\/li>\r\n \t
- EPDM<\/li>\r\n \t
- FKM\/Viton<\/li>\r\n \t
- BUNA-N<\/li>\r\n \t
- SI\/Silicone rubber<\/li>\r\n \t
- Leather<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n\r\nFluorine Plastic Type<\/strong>\r\n\r\n\r\n\r\n\r\n
\r\n \t- FEP, with EPDM backing<\/li>\r\n \t
- PTFE, with EPDM backing<\/li>\r\n \t
- PFA, with EPDM backing<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
Diaphragm Valve Compressor<\/h3>\r\n\r\n\r\n\r\n\r\nThe compressor is a disc that lies between the valve stem and the diaphragm. It supports the diaphragm valve and distributes the forces from the stem during linear movement. The compressor design is optimized to provide better flow throttling and control.\r\n\r\n\r\n\r\n\r\nDiaphragm Valve Stem<\/h3>\r\n\r\n\r\n\r\n\r\nThe stem is a vertical shaft connected to the compressor that exerts linear motion to move both compressor and diaphragm, thus operating the diaphragm valve. It transmits the motion exerted by the actuator. Diaphragm valves can either have piston- or threaded-type stems. As the name implies, piston-type valves are moved by a piston assembly inside the bonnet, with the valve stem likely acting as the piston rod. This type requires linear force exerted by fluid pressure. Threaded stem valves have a matching stem nut. This type requires torque to linearly move the stem, as well as lubrication for smooth motion.\r\n\r\n\r\n\r\n\r\n\r\nThe threaded stems of diaphragm valves can have a rising or non-rising mechanism:\r\n\r\n\r\n\r\n\r\n\r\n \t- Rising Stem<\/strong>: Rising stems or indicating stems extend their length up to the handwheel. As the handwheel is turned, the stem rises or descends to open or close the valve, respectively. Hence, it is easier to determine the extent to which the valve is opened by looking at the amount of stem exposed. However, rising stems take up more space than non-rising stems.<\/li>\r\n \t
- Non-Rising Stem:<\/strong> Non-rising stems or non-indicating stems are rotated to open or close the valve, but it does not cause the stem to move up or down. Non-rising stem valves are used in limited spaces, such as in underground piping systems.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
Advantages and Disadvantages of Diaphragm Valves<\/h2>\r\n\r\n\r\n\r\n\r\n
- La vanne \u00e0 membrane de type d\u00e9versoir est l'une des conceptions les plus courantes disponibles et correspond \u00e0 celle illustr\u00e9e \u00e0 la figure 2 ci-dessus. La conception \u00e0 l\u00e8vre\/selle sur\u00e9lev\u00e9e est la mieux adapt\u00e9e au contr\u00f4le de petit d\u00e9bit et reste \u00e9tanche gr\u00e2ce au chapeau sur le diaphragme et l'actionneur. Cette conception est optimale pour les liquides et gaz dangereux ou corrosifs, car toute d\u00e9faillance de la membrane sera contenue par ce capot. De plus, le corps inclin\u00e9 rend cette vanne intrins\u00e8quement auto-drainante, mais cette vidange peut se produire dans les deux sens de la vanne, ce qui peut ne pas \u00eatre optimal pour certaines applications. La vanne de type d\u00e9versoir est principalement sp\u00e9cifi\u00e9e pour les fluides propres et homog\u00e8nes, car des boues visqueuses et des s\u00e9diments peuvent s'accumuler de chaque c\u00f4t\u00e9 de la selle. On les trouve le plus souvent dans des processus tels que les applications alimentaires\/chimiques, la production de gaz, les applications corrosives et l'eau.<\/li><\/ul><\/li>
- Vannes \u00e0 membrane de type traversant droit<\/strong>
- La vanne \u00e0 membrane directe est structurellement similaire aux types \u00e0 d\u00e9versoir\u00a0; cependant, il ne contient pas la selle caract\u00e9ristique et a plut\u00f4t un chemin compl\u00e8tement droit. Leurs membranes sont g\u00e9n\u00e9ralement plus flexibles et permettent une distance de d\u00e9placement plus longue, car elles doivent toucher tout le bas de la valve. Ces vannes doivent souvent \u00eatre entretenues\/remplac\u00e9es, car leur dur\u00e9e de vie est g\u00e9n\u00e9ralement inf\u00e9rieure \u00e0 celle des conceptions \u00e0 d\u00e9versoir en raison de leurs membranes plus flexibles. Les vannes \u00e0 membrane directe sont utilis\u00e9es pour les boues, les fluides visqueux et d'autres applications o\u00f9 le blocage doit \u00eatre r\u00e9duit. Ils sont \u00e9galement utiles pour les r\u00e9gimes d'\u00e9coulement bidirectionnels, car il n'y a pas de selle pour emp\u00eacher le passage rapide de l'entr\u00e9e \u00e0 la sortie.<\/li><\/ul><\/li><\/ul>\n\n\n\n
Avantages des vannes \u00e0 membrane ?<\/h2>\n\n\n\n
- Les vannes \u00e0 membrane peuvent \u00e9galement \u00eatre utilis\u00e9es pour le service d'\u00e9tranglement.<\/li>
- Ses caract\u00e9ristiques d'\u00e9tranglement sont essentiellement celles d'une vanne \u00e0 ouverture rapide en raison de la grande zone d'arr\u00eat le long du si\u00e8ge.<\/li>
- Une vanne \u00e0 membrane de type d\u00e9versoir est disponible pour contr\u00f4ler les petits d\u00e9bits.<\/li>
- Les vannes \u00e0 membrane sont particuli\u00e8rement adapt\u00e9es \u00e0 la manipulation de fluides corrosifs, de boues fibreuses, de fluides radioactifs ou d'autres fluides qui doivent rester exempts de contamination.<\/li>
- Le m\u00e9canisme de fonctionnement d'une vanne \u00e0 membrane n'est pas expos\u00e9 aux fluides pr\u00e9sents dans la canalisation. Les fluides collants ou visqueux ne peuvent pas p\u00e9n\u00e9trer dans le capot et interf\u00e9rer avec le m\u00e9canisme de fonctionnement.<\/li>
- De nombreux fluides susceptibles d'obstruer, de corroder ou de gommer les pi\u00e8ces actives de la plupart des autres types de vannes passeront \u00e0 travers une vanne \u00e0 membrane sans causer de probl\u00e8mes. \u00c0 l\u2019inverse, les lubrifiants utilis\u00e9s pour le m\u00e9canisme de commande ne peuvent pas contaminer le fluide manipul\u00e9.<\/li>
- Il n\u2019y a aucun presse-\u00e9toupe \u00e0 entretenir et aucune possibilit\u00e9 de fuite de tige dans les vannes.<\/li><\/ul>\n\n\n\n\n
Balises associ\u00e9es :<\/h2>\n\n\n\n\n
\nSoupape ZECO<\/a>\n\n<\/div>\n\n\n\n\nDiff\u00e9rence entre la vanne \u00e0 vanne et la vanne papillon<\/a>\n\n<\/div>\n\n\n\n\nQue sont les vannes \u00e0 soupape\u00a0?<\/a>\n\n<\/div>\n\n\n\n\nFabricant de robinets-vannes \u00e0 commande manuelle<\/a>\n\n<\/div>\n\n\n\n\nQu'est-ce qu'un robinet-vanne ?<\/a>\n\n<\/div>\n\n\n\n\nUsine de soupapes de r\u00e9duction de pression de Shanghai<\/a>\n\n<\/div>\n\n\n\n\nQue sont les vannes de r\u00e9gulation automatique ?<\/a>\n\n<\/div>\n\n\n\n\nRobinet \u00e0 soupape et robinet \u00e0 bille<\/a>\n\n<\/div>\n\n\n\n\nFournisseur de vannes \u00e0 vanne de 12 pouces<\/a>\n\n<\/div>\n\n\n\n\nMat\u00e9riaux thermoplastiques comme si\u00e8ge de robinet \u00e0 tournant sph\u00e9rique et si\u00e8ge de vanne papillon<\/a>\n\n<\/div>","protected":false},"excerpt":{"rendered":"Dans la plupart des situations, les vannes \u00e0 membrane ne constituent pas une consid\u00e9ration importante. Mais lorsqu\u2019une vanne peut am\u00e9liorer vos performances dans les processus en aval, elle\u2026 Lire plus<\/a><\/p>","protected":false},"author":2,"featured_media":13348,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_generate-full-width-content":"","kt_blocks_editor_width":"","footnotes":""},"categories":[1],"tags":[2702,2704,2703,3205],"class_list":["post-3059","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-diaphragm-valve","tag-diaphragm-valve-diagram","tag-diaphragm-valve-function","tag-diaphragm-valve-manufacturers","generate-columns","tablet-grid-50","mobile-grid-100","grid-parent","grid-50"],"featured_image_src_large":["https:\/\/zecovalve.com\/wp-content\/uploads\/2022\/01\/20220105083122-61d5575ae65f4.jpg",924,1004,false],"author_info":{"display_name":"Jerry","author_link":"https:\/\/zecovalve.com\/fr\/author\/jerry"},"comment_info":0,"category_info":[{"term_id":1,"name":"Uncategorized","slug":"uncategorized","term_group":0,"term_taxonomy_id":1,"taxonomy":"category","description":"","parent":0,"count":452,"filter":"raw","cat_ID":1,"category_count":452,"category_description":"","cat_name":"Uncategorized","category_nicename":"uncategorized","category_parent":0}],"tag_info":[{"term_id":2702,"name":"Diaphragm Valve","slug":"diaphragm-valve","term_group":0,"term_taxonomy_id":2702,"taxonomy":"post_tag","description":"","parent":0,"count":3,"filter":"raw"},{"term_id":2704,"name":"diaphragm valve diagram","slug":"diaphragm-valve-diagram","term_group":0,"term_taxonomy_id":2704,"taxonomy":"post_tag","description":"","parent":0,"count":2,"filter":"raw"},{"term_id":2703,"name":"Diaphragm Valve Function","slug":"diaphragm-valve-function","term_group":0,"term_taxonomy_id":2703,"taxonomy":"post_tag","description":"\r\n\r\n\r\n\r\nGET DIAPHRAGM VALVE DIAGRAM INFORMATION<\/strong><\/a>\r\n\r\n\r\n\r\n\r\n
What is a Diaphragm Valve?<\/h2>\r\n\r\n\r\n\r\n\r\nDiaphragm valves get their name from a flexible disc that comes into contact with a seat at the top of the valve body to form a seal. A diaphragm is a flexible, pressure-responsive element that transmits force to open, close, or control a valve. Diaphragm valves are related to pinch valves, but use an elastomeric diaphragm, instead of an elastomeric liner in the valve body, to separate the flow stream from the closure element.\r\n\r\n\r\n\r\n\r\n
<\/figure>\r\n\r\n\r\n\r\nHow do Diaphragm Valves Work?<\/h2>\r\n\r\n\r\n\r\n\r\nDiaphragm valves are simple in construction and operation. A valve actuator is in contact with the inner membrane (or \u201cdiaphragm\u201d) of the valve in its open position. When the user desires the valve to be shut, the actuator is pressed and\/or turned and the membrane is pushed into the edge of the solid damn, closing the valve. Certain diaphragm valves can also have half open\/restricted positions where the membrane is partially closed, allowing a throttled flow through the valve. In the next section, we will examine the broad categories of diaphragm valves and where they are most useful.\r\n\r\n\r\n\r\n\r\n
Types of Diaphragm Valves<\/h2>\r\n\r\n\r\n\r\n
Weir-Type Diaphragm Valves<\/h3>\r\n\r\n\r\n\r\n\r\nThe weir-type diaphragm valve is one of the most common designs available and is what is shown in Figure 2, above. The raised lip\/saddle design is best suited for small flow control and is kept leak-proof thanks to the bonnet over the diaphragm and actuator. This design is optimal for dangerous or corrosive liquid and gas, as any failure with the membrane will be kept contained by this bonnet. Also, the sloped body makes this valve inherently self-draining, but this draining can happen in both valve directions which may not be optimal for some applications. The weir-type valve is mostly specified for clean, homogenous fluids, as viscous slurries and sediments may build up on either side of the saddle. They are most often found in processes such as food\/chemical, gas production, corrosive, and water applications.\r\n\r\n\r\n\r\n\r\n
Straight Through Type Diaphragm Valves<\/h3>\r\n\r\n\r\n\r\n\r\nThe straight-through diaphragm valve is structurally similar to weir-types; however, it does not contain the characteristic saddle and instead has a completely straight pathway. Their membranes are typically more flexible and allow for farther travel distance, as it must touch the very bottom of the valve. These valves must often be serviced\/replaced, as their lifespan is typically less than weir-type designs due to their more flexible membranes. Straight-through diaphragm valves are used for slurries, viscous fluids, and other applications where blocking must be reduced. They are also useful for bi-directional flow regimes, as there is no saddle to impede swift changing from inlet to outlet.\r\n\r\n\r\n\r\n\r\n
Diaphragm Valve Parts<\/h2>\r\n\r\n\r\n\r\n\r\nThe components of diaphragm valves are the following:\r\n\r\n\r\n\r\n\r\n
Diaphragm Valve Bonnet<\/h3>\r\n\r\n\r\n\r\n\r\nThe bonnet serves as the top cover and is bolted to the valve body. It protects the compressor, stem, diaphragm, and other non-wetted components of the diaphragm valve.\r\n\r\n\r\n\r\n\r\n
Diaphragm Valve Body<\/h3>\r\n\r\n\r\n\r\n\r\nThe valve body is the component directly connected to the pipeline wherein the fluid passes. The flow area inside the valve body depends on the type of diaphragm valve.\r\n\r\n\r\n\r\n\r\n\r\nBoth the valve body and bonnet are constructed from strong, rigid, and corrosive resistant materials.\r\n\r\n\r\n\r\n\r\n
Diaphragm Valve Diaphragm<\/h3>\r\n\r\n\r\n\r\n\r\nThe diaphragm is made from a highly elastic polymeric disc that moves down to touch the bottom of the valve body to limit or obstruct the passage of fluid. The diaphragm lifts if the fluid flow rate is to be increased or the valve is to be fully opened. The fluid flows underneath the diaphragm. However, this component limits the valve\u2019s operating temperature and pressure due to the diaphragm\u2019s material and structure. It must also be replaced periodically since its mechanical properties degrade during usage.\r\n\r\n\r\n\r\n\r\n\r\nThe diaphragm isolates the non-wetted components (compressor, stem, and actuator) from the flowing media. Therefore, solids and viscous fluids are less likely to interfere with the operating mechanism of the diaphragm valve. This also protects the non-wetted components from corrosion. Conversely, the fluid in the pipeline will not be contaminated with the lubricant used in operating the valve.\r\n\r\n\r\n\r\n\r\n
Material of Diaphragm Valve Diaphragm<\/h4>\r\n\r\n\r\n\r\n\r\nUnlined or Rubber Lined Type<\/strong>\r\n\r\n\r\n\r\n\r\n
- \r\n \t
- NR\/Natural Rubber<\/li>\r\n \t
- NBR\/Nitrile\/Buna-N<\/li>\r\n \t
- EPDM<\/li>\r\n \t
- FKM\/Viton<\/li>\r\n \t
- BUNA-N<\/li>\r\n \t
- SI\/Silicone rubber<\/li>\r\n \t
- Leather<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n\r\nFluorine Plastic Type<\/strong>\r\n\r\n\r\n\r\n\r\n
- \r\n \t
- FEP, with EPDM backing<\/li>\r\n \t
- PTFE, with EPDM backing<\/li>\r\n \t
- PFA, with EPDM backing<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
Diaphragm Valve Compressor<\/h3>\r\n\r\n\r\n\r\n\r\nThe compressor is a disc that lies between the valve stem and the diaphragm. It supports the diaphragm valve and distributes the forces from the stem during linear movement. The compressor design is optimized to provide better flow throttling and control.\r\n\r\n\r\n\r\n\r\n
Diaphragm Valve Stem<\/h3>\r\n\r\n\r\n\r\n\r\nThe stem is a vertical shaft connected to the compressor that exerts linear motion to move both compressor and diaphragm, thus operating the diaphragm valve. It transmits the motion exerted by the actuator. Diaphragm valves can either have piston- or threaded-type stems. As the name implies, piston-type valves are moved by a piston assembly inside the bonnet, with the valve stem likely acting as the piston rod. This type requires linear force exerted by fluid pressure. Threaded stem valves have a matching stem nut. This type requires torque to linearly move the stem, as well as lubrication for smooth motion.\r\n\r\n\r\n\r\n\r\n\r\nThe threaded stems of diaphragm valves can have a rising or non-rising mechanism:\r\n\r\n\r\n\r\n\r\n
- \r\n \t
- Rising Stem<\/strong>: Rising stems or indicating stems extend their length up to the handwheel. As the handwheel is turned, the stem rises or descends to open or close the valve, respectively. Hence, it is easier to determine the extent to which the valve is opened by looking at the amount of stem exposed. However, rising stems take up more space than non-rising stems.<\/li>\r\n \t
- Non-Rising Stem:<\/strong> Non-rising stems or non-indicating stems are rotated to open or close the valve, but it does not cause the stem to move up or down. Non-rising stem valves are used in limited spaces, such as in underground piping systems.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
Advantages and Disadvantages of Diaphragm Valves<\/h2>\r\n\r\n\r\n\r\n
\r\n - Non-Rising Stem:<\/strong> Non-rising stems or non-indicating stems are rotated to open or close the valve, but it does not cause the stem to move up or down. Non-rising stem valves are used in limited spaces, such as in underground piping systems.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n
- Rising Stem<\/strong>: Rising stems or indicating stems extend their length up to the handwheel. As the handwheel is turned, the stem rises or descends to open or close the valve, respectively. Hence, it is easier to determine the extent to which the valve is opened by looking at the amount of stem exposed. However, rising stems take up more space than non-rising stems.<\/li>\r\n \t
- La vanne \u00e0 membrane directe est structurellement similaire aux types \u00e0 d\u00e9versoir\u00a0; cependant, il ne contient pas la selle caract\u00e9ristique et a plut\u00f4t un chemin compl\u00e8tement droit. Leurs membranes sont g\u00e9n\u00e9ralement plus flexibles et permettent une distance de d\u00e9placement plus longue, car elles doivent toucher tout le bas de la valve. Ces vannes doivent souvent \u00eatre entretenues\/remplac\u00e9es, car leur dur\u00e9e de vie est g\u00e9n\u00e9ralement inf\u00e9rieure \u00e0 celle des conceptions \u00e0 d\u00e9versoir en raison de leurs membranes plus flexibles. Les vannes \u00e0 membrane directe sont utilis\u00e9es pour les boues, les fluides visqueux et d'autres applications o\u00f9 le blocage doit \u00eatre r\u00e9duit. Ils sont \u00e9galement utiles pour les r\u00e9gimes d'\u00e9coulement bidirectionnels, car il n'y a pas de selle pour emp\u00eacher le passage rapide de l'entr\u00e9e \u00e0 la sortie.<\/li><\/ul><\/li><\/ul>\n\n\n\n