Typically,\nonce a fan system is designed and installed, the fan operates at a constant\nspeed.<\/p>\n\n\n\n
There are\nalso instances when the fan is over size land flow reduction is required.<\/p>\n\n\n\n
Various ways\nto achieve change in flow are pulley change, damper control, inlet guide vane\ncontrol, variable speed drive and series and parallel\noperation of fans.<\/p>\n\n\n\n
(1)Pulley\nchange :<\/strong><\/p>\n\n\n\n When a fan\nvolume change is required on a permanent basis, and the existing fan can handle\nthe change in capacity, the volume change can be achieved with a speed change.<\/p>\n\n\n\n The simplest\nway to change the speed is with a pulley change. For this, the fan must be\ndriven by a motor through a v-belt system.<\/p>\n\n\n\n (2)Damper\ncontrols :<\/strong><\/p>\n\n\n\n Dampers can\nbe located at inlet or outlet of fan<\/p>\n\n\n\n They provide\na means of changing air volume by adding or removing system resistance.<\/p>\n\n\n\n This\nresistance forces the fan to move up or down along its characteristic curve,\ngenerating more or less air without changing fan speed<\/p>\n\n\n\n (3)Inlet\nguide vanes<\/strong>:<\/p>\n\n\n\n Inlet guide\nvanes are another mechanism that can be used to meet variable air demand.<\/p>\n\n\n\n Guide vanes\nare curved sections that lay against the inlet of the fan when they are open.<\/p>\n\n\n\n When they\nare closed, they extend out into the air stream.<\/p>\n\n\n\n As they are\nclosed, guide vanes pre-swirl the air entering the fan housing. This changes\nthe angle at which the air is presented to the fan blades, which, in turn,\nchanges the characteristics of the fan curve.<\/p>\n\n\n\n Axial-flow\nfans can be equipped with variable pitch blades, which can be hydraulically or\npneumatically controlled to change blade pitch, while the fan is at stationary.<\/p>\n\n\n\n (4)\nVariable speed drives :<\/strong><\/p>\n\n\n\n Variable\nspeed control may not be economical for systems, which have in frequent flow\nvariations.<\/p>\n\n\n\n When\nconsidering variable speed drive, the efficiency of the control system (fluid\ncoupling, eddy current, VFD, etc.) should be accounted for, in the analysis of\npower consumption.<\/p>\n\n\n\n (5)Series\nand parallel operation :<\/strong><\/p>\n\n\n\n Fans in\nparallel can be additionally equipped with dampers, variable inlet vanes,\nvariable-pitch blades, or speed control to provide a high degree of flexibility\nand reliability.<\/p>\n\n\n\n Combining\nfor series or parallel can achieve the desired airflow without greatly\nincreasing the system package size or fan diameter.<\/p>\n\n\n\n Parallel\noperation is defined as having two or more fans blowing together side by side.<\/p>\n\n\n\n The\nperformance of two fans in parallel will result in doubling the volume flow,\nbut only at free delivery<\/p>\n\n\n\n Series\noperation can be defined as using multiple fans in a push-pull arrangement.<\/p>\n\n\n\n By staging\ntwo fans in series, the static pressure capability at a given airflow can be\nincreased, but again, not to double at every flow point.<\/p>\n","protected":false},"excerpt":{"rendered":" Typically, once a fan system is designed and installed, the fan operates at a constant speed. There are also instances when the fan is over size land flow reduction is required. Various ways to achieve change in flow are pulley change, damper control, inlet guide vane control, variable speed drive and series and parallel operation […]<\/p>\n","protected":false},"author":1,"featured_media":828,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-827","page","type-page","status-publish","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/pages\/827","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/comments?post=827"}],"version-history":[{"count":1,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/pages\/827\/revisions"}],"predecessor-version":[{"id":830,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/pages\/827\/revisions\/830"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/media\/828"}],"wp:attachment":[{"href":"https:\/\/www.zillionsbuyer.com\/blog\/wp-json\/wp\/v2\/media?parent=827"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}