{"id":4876,"date":"2026-09-23T05:37:55","date_gmt":"2026-09-23T05:37:55","guid":{"rendered":"https:\/\/sayiair.com\/?p=4876"},"modified":"2026-09-23T05:37:56","modified_gmt":"2026-09-23T05:37:56","slug":"how-to-size-an-oil-free-scroll-air-compressor","status":"publish","type":"post","link":"https:\/\/sayiair.com\/ru\/how-to-size-an-oil-free-scroll-air-compressor\/","title":{"rendered":"How to Size an Oil-Free Scroll Air Compressor: Flow, Duty Cycle and Receiver Tank Math"},"content":{"rendered":"<p class=\"wp-block-paragraph\">The spec sheet said 2.2 kW. The old unit had been 2.2 kW. So the replacement was ordered to match, bolted in, and switched on \u2014 and within a week the dental lab was complaining that two handpieces running together starved the third.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The new compressor was not underpowered. It was asked to deliver steady continuous flow from a package whose rating was quoted at a different reference pressure than the old one, feeding a smaller receiver tank, in a plant where the peak demand lasted longer than anyone had measured. Three errors, none of them horsepower.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Scroll compressors are forgiving machines, but they are not immune to bad arithmetic. Here is how to size one properly \u2014 the sequence we walk buyers through before quoting.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Start with demand, not horsepower<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Motor power is an input. What your process consumes is flow at pressure, and it should be measured rather than guessed.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Two practical ways to get the number:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Tool-by-tool audit.<\/strong> List every consumer, note its rated consumption and convert to a common unit. Note also which devices can run simultaneously \u2014 a compressed-air audit almost always finds that the installed tool nameplate total far exceeds realistic concurrent demand.<\/li>\n\n\n\n<li><strong>Existing system observation.<\/strong> Install a temporary flow meter, or watch how far the pressure gauge falls during a peak draw and how long the compressor takes to recover. That recovery time is direct evidence of the gap between consumption and pumping capacity.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Then apply a <strong>diversity factor<\/strong> to simultaneous use. Sizing to the arithmetic sum of every tool in the building typically produces a unit 30\u201350% larger than needed, which costs more to buy and more to run at part load.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Reading a scroll rating without getting fooled<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Three things on a scroll spec sheet routinely mislead:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Reference pressure.<\/strong> Flow quoted at 7 bar is not comparable to flow quoted at 10 bar. Higher discharge pressure means lower delivered flow from the same machine. Always convert to the pressure you will actually run at.<\/li>\n\n\n\n<li><strong>Free air delivery vs. displacement.<\/strong> Displacement is swept volume \u2014 the geometric amount the scrolls move. Free air delivery is what actually comes out of the outlet. The second number is always smaller.<\/li>\n\n\n\n<li><strong>Voltage.<\/strong> Single-phase 220 V availability caps what you can install in most buildings. Our <a href=\"https:\/\/sayiair.com\/ru\/product\/sy-sf3-10-2-2kw-220v-oil-free-scroll-air-compressor-10-bar\/\">SY-SF3\/10 in 220 V form<\/a> covers sites with no three-phase supply; where three-phase exists, the same machine is built as a <a href=\"https:\/\/sayiair.com\/ru\/product\/sy-sf3-10-2-2kw-380v-3ph-oil-free-scroll-air-compressor-10-bar\/\">380 V unit<\/a> with better motor economics.<\/li>\n<\/ol>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"572\" height=\"588\" src=\"https:\/\/sayiair.com\/wp-content\/uploads\/2026\/09\/image-2.png\" alt=\"\" class=\"wp-image-4884\" title=\"\" srcset=\"https:\/\/sayiair.com\/wp-content\/uploads\/2026\/09\/image-2.png 572w, https:\/\/sayiair.com\/wp-content\/uploads\/2026\/09\/image-2-12x12.png 12w, https:\/\/sayiair.com\/wp-content\/uploads\/2026\/09\/image-2-292x300.png 292w\" sizes=\"(max-width: 572px) 100vw, 572px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Our current range steps through three capacities, all rated to 10 bar:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u041c\u043e\u0434\u0435\u043b\u044c<\/th><th>\u041c\u043e\u0449\u043d\u043e\u0441\u0442\u044c \u0434\u0432\u0438\u0433\u0430\u0442\u0435\u043b\u044f<\/th><th>Supply<\/th><th>Notes<\/th><\/tr><\/thead><tbody><tr><td>SY-SF3\/10<\/td><td>2.2 kW<\/td><td>220 V single-phase or 380 V three-phase<\/td><td>Entry unit for clinics and small labs<\/td><\/tr><tr><td>SY-SF5\/10<\/td><td>3.7 kW<\/td><td>Three-phase<\/td><td>IP54 motor for dusty sites<\/td><\/tr><tr><td>SY-SF7.5\/10<\/td><td>5.5 kW<\/td><td>Three-phase<\/td><td>Around 505 L\/min delivered<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Full details are on each product page \u2014 this table is for the selection conversation, not the purchase specification.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Duty cycle: where scroll genuinely differs<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Scroll air ends are capable of continuous duty, which is why they replaced piston units in many professional settings. But &#8220;capable of continuous duty&#8221; is a statement about the air end, not about the whole package. In the real installation the constraint is usually one of two things:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Motor thermal load.<\/strong> Continuous operation in a hot, unventilated cupboard is the most common cause of premature scroll failure. Room temperature and airflow across the motor decide whether 100% duty is honest.<\/li>\n\n\n\n<li><strong>Duty cycle of the downstream process.<\/strong> Intermittent peaks are better served by a receiver than by a bigger pump \u2014 see the next section.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">As a working rule: if average consumption is below roughly 60% of the compressor&#8217;s continuous output, you are in intermittent territory and a correctly sized tank will let you install a smaller machine. Above that, size the compressor to the load and use the tank only for stabilisation.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Receiver tank sizing, without guessing<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The receiver is the cheapest capacity you can buy. It covers short peak demands, smooths the pressure swings, removes some condensate, and stops the motor from short-cycling itself to death.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A usable approximation for buffer storage:<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\"><strong>V (litres) \u2248 Q (L\/min) \u00d7 t (minutes) \u00f7 \u0394p (bar)<\/strong><\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">Where <strong>V<\/strong> is tank volume, <strong>Q<\/strong> is the extra flow above compressor output during the peak, <strong>t<\/strong> is how long the peak lasts, and <strong>\u0394p<\/strong> is how much pressure drop you can tolerate before the process notices.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Worked example: handpieces and a suction unit together draw 400 L\/min for 30 seconds, the compressor supplies 200 L\/min continuously, and the process tolerates a drop from 10 bar to 8 bar.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Extra flow above supply: 400 \u2212 200 = 200 L\/min<\/li>\n\n\n\n<li>Duration: 0.5 minutes<\/li>\n\n\n\n<li>Allowed pressure drop: 2 bar<\/li>\n\n\n\n<li>V \u2248 200 \u00d7 0.5 \u00f7 2 = <strong>50 litres minimum<\/strong><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Add margin \u2014 typically 30\u201350% \u2014 and spec 75\u2013100 litres. In practice this is why units ship matched with receivers rather than bare: the <a href=\"https:\/\/sayiair.com\/ru\/product\/sayi-sy-750-2250w-oil-free-silent-air-compressor-8-bar-200l\/\">SY-750 silent unit<\/a> carries a 200 L tank precisely so peaks do not have to be met by the pump.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Build modular capacity instead of one big unit<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Scroll packages are natively modular. Two mid-size units running in parallel with sequenced control give you:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Part-load efficiency<\/strong> \u2014 one unit runs near its efficient point instead of one large machine throttling.<\/li>\n\n\n\n<li><strong>Redundancy<\/strong> \u2014 a service interval or a fault costs you a share of capacity, not the whole supply.<\/li>\n\n\n\n<li><strong>Staged capital<\/strong> \u2014 add the second unit when demand actually arrives rather than paying for it years early.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The trade-off is floor space and a control panel to manage sequencing. For a plant of any size, that trade is usually worth taking.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For example, the step from the 3.7 kW SF5\/10 to the 5.5 kW SF7.5\/10 is not your only lever: two SF5\/10 units in parallel may serve a variable load better than one larger machine.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Do not forget drying and filtration<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Oil-free means no oil. It does <strong>not<\/strong> mean dry.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Every cubic metre drawn from the atmosphere carries water vapour, and compressing it concentrates that water. It condenses in the tank, runs down your pipework and reaches the point of use. If your application is instrument air, powder handling, food contact or painting, specify the dew point as carefully as the flow.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A <a href=\"https:\/\/sayiair.com\/ru\/product-category\/air-dryer\/\">refrigerated air dryer<\/a> is the standard answer for general applications \u2014 the <a href=\"https:\/\/sayiair.com\/ru\/product\/cd-36f-1kw-127cfm-10bar-dehumidifier-air-dryer\/\">CD-36F unit<\/a> is typical of the compact end that labs pair with a scroll package. If you are buying several, our notes on <a href=\"https:\/\/sayiair.com\/ru\/bulk-purchasing-air-dryers-from-china\/\">bulk purchasing air dryers<\/a> are worth five minutes.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">A four-step sizing worksheet<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Run these in order and the number falls out cleanly:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Measure concurrent demand<\/strong> \u2014 not the nameplate total. Record flow in L\/min at your working pressure over a representative hour.<\/li>\n\n\n\n<li><strong>Determine duty profile<\/strong> \u2014 what share of each ten-minute window is the compressor actually loaded? Below roughly 60% average, plan on receiver storage; above it, size the pump for continuous output.<\/li>\n\n\n\n<li><strong>Size the receiver<\/strong> for the longest credible peak using the formula above, plus 30\u201350% margin.<\/li>\n\n\n\n<li><strong>Specify air treatment<\/strong> against the dew point your process needs, then add filtration if particles matter.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">If any of those steps produces an uncomfortable number, talk to us before ordering \u2014 send the details via the <a href=\"https:\/\/sayiair.com\/ru\/contact\/\">\u0441\u0442\u0440\u0430\u043d\u0438\u0446\u0430 \u00ab\u041a\u043e\u043d\u0442\u0430\u043a\u0442\u044b\u00bb<\/a> and we will check the arithmetic against your actual process.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u0427\u0430\u0441\u0442\u043e \u0437\u0430\u0434\u0430\u0432\u0430\u0435\u043c\u044b\u0435 \u0432\u043e\u043f\u0440\u043e\u0441\u044b<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">How much oversizing is sensible?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">15\u201320% above measured peak concurrent demand is the usual figure. More than that and you pay for capacity you will not use, plus the part-load penalty of running a larger machine below its efficient point.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Can I run a scroll compressor continuously at full load?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The air end is designed for it, provided the package gets the ambient temperature and ventilation it needs. Continuous operation in a sealed cupboard is the single most common cause of shortened scroll life.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Single-phase or three-phase?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Whatever your building supply allows, with a preference for three-phase where it exists \u2014 380 V motors generally run cooler and are cheaper to buy per kilowatt. Where only single-phase is available, the 220 V SF3\/10 covers low-throughput applications.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Why does my scroll unit cycle on and off?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Usually an undersized receiver relative to the peak draw, or a pressure band set too tightly between cut-in and cut-out. Either add storage or widen the differential \u2014 cycling itself is what wears the motor and starter, not steady running.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Where does scroll sit compared with screw and piston?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Scroll wins where air cleanliness, low noise and low-to-medium flow meet \u2014 typically below a whole-plant scale. Above that, rotary screw takes over. Our comparison of <a href=\"https:\/\/sayiair.com\/ru\/piston-vs-screw-vs-scroll-air-compressor-duty-cycle\/\">piston, screw and scroll technologies<\/a> walks the boundaries in detail.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Browse the full <a href=\"https:\/\/sayiair.com\/ru\/product-category\/oil-free-scroll-air-compressor\/\">\u043b\u0438\u043d\u0435\u0439\u043a\u0430 \u0441\u043f\u0438\u0440\u0430\u043b\u044c\u043d\u044b\u0445 \u043a\u043e\u043c\u043f\u0440\u0435\u0441\u0441\u043e\u0440\u043e\u0432 \u0431\u0435\u0437\u043c\u0430\u0441\u043b\u044f\u043d\u043e\u0433\u043e \u0442\u0438\u043f\u0430<\/a> or read our broader guide to <a href=\"https:\/\/sayiair.com\/ru\/the-future-of-compressed-air-solutions-the-oil-free-air-compressor\/\">the future of oil-free compressed air<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>","protected":false},"excerpt":{"rendered":"<p>Size an oil-free scroll compressor in four steps: real demand, duty cycle, receiver tank math, then drying. Includes the buffer-tank formula and a worked example.<\/p>","protected":false},"author":1,"featured_media":4873,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_joinchat":[],"footnotes":""},"categories":[3,32],"tags":[],"class_list":["post-4876","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-resources","category-blog"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/sayiair.com\/ru\/wp-json\/wp\/v2\/posts\/4876","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sayiair.com\/ru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sayiair.com\/ru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sayiair.com\/ru\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/sayiair.com\/ru\/wp-json\/wp\/v2\/comments?post=4876"}],"version-history":[{"count":3,"href":"https:\/\/sayiair.com\/ru\/wp-json\/wp\/v2\/posts\/4876\/revisions"}],"predecessor-version":[{"id":4887,"href":"https:\/\/sayiair.com\/ru\/wp-json\/wp\/v2\/posts\/4876\/revisions\/4887"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/sayiair.com\/ru\/wp-json\/wp\/v2\/media\/4873"}],"wp:attachment":[{"href":"https:\/\/sayiair.com\/ru\/wp-json\/wp\/v2\/media?parent=4876"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sayiair.com\/ru\/wp-json\/wp\/v2\/categories?post=4876"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sayiair.com\/ru\/wp-json\/wp\/v2\/tags?post=4876"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}