{"id":19740,"date":"2025-12-12T15:52:56","date_gmt":"2025-12-12T14:52:56","guid":{"rendered":"https:\/\/www.darda.de\/?page_id=19740"},"modified":"2026-05-18T12:32:02","modified_gmt":"2026-05-18T10:32:02","slug":"hose-bore","status":"publish","type":"page","link":"https:\/\/www.darda.de\/en\/knowledge\/hose-bore","title":{"rendered":"Hose bore"},"content":{"rendered":"<div class=\"wissen-inhaltsbereich\">\n<p>The hose bore is a central parameter in the <em>hydraulics<\/em> of demolition and cutting technology. It largely determines how much fluid a hose and its connection components can safely transport per unit of time. In Darda GmbH applications &#8211; such as <a href=\"https:\/\/www.darda.de\/en\/product-overview\/hydraulic-rock-and-concrete-splitters\">hydraulic rock and concrete splitters<\/a>, concrete demolition shears, combination shears, or steel shears &#8211; the correct hose bore directly affects working speed, energy efficiency, and the thermal load of the overall system. Especially in <em>concrete demolition<\/em>, <em>special demolition<\/em>, rock excavation, and <em>tunnel construction<\/em>, the right sizing ensures precise, reproducible sequences, short cycle times, and calm, controlled operation. In practice, accurate hose sizing also improves component longevity by limiting pressure peaks and friction losses in continuous duty.<\/p>\n<h2>Definition: What is meant by the hose bore?<\/h2>\n<p>Hose bore refers to the inner diameter of a hydraulic hose, often designated as <em>inner \u00d8<\/em>, <em>ID<\/em>, or nominal diameter <strong>DN<\/strong>. In day-to-day technical usage, the term functionally also includes the <em>narrowest point<\/em> of the entire line &#8211; such as reductions in couplings, fittings, adapters, elbows, or valves. This narrowest point defines the maximum possible flow rate for a given pressure drop. The hose bore is therefore a flow cross-section that determines the flow rate, the pressure drop, the heating of the medium, and ultimately the speed of cylinders, shears, or splitting wedges. As a rule of thumb, the required area A follows A = Q\/v, with the inner diameter d derived from d = \u221a(4A\/\u03c0) &#8211; a practical relation when translating delivery rate and target flow velocity into an ID selection. DN values typically approximate inner diameters in millimeters but must always be verified against manufacturer data sheets.<\/p>\n<h2>Structure and designation: DN, inner \u00d8, and the narrowest point in the line<\/h2>\n<p>Hydraulic hoses consist of an inner tube, several reinforcement\/pressure-bearing layers, and an outer cover. Decisive for sizing is the <strong>inner bore<\/strong>. Metric specifications in millimeters as well as nominal diameters (DN) are common. Important: Effective flow capacity is often limited not by the hose alone but by <em>quick couplings, hose fittings<\/em>, and their <em>insertion parts<\/em>. In practice, the smallest bore along the line governs the flow. Anyone sizing the hose bore therefore always considers the complete section from the <em>hydraulic power pack<\/em> to the tool &#8211; including pressure line, return line, and control lines.<\/p>\n<p><strong>Typical restriction points along the line:<\/strong><\/p>\n<ul>\n<li>Quick couplings with undersized through-bore<\/li>\n<li>Adapters, reducers, and elbows with sharp internal transitions<\/li>\n<li>Check valves, flow dividers, and throttle points<\/li>\n<li>Swivel joints or rotary unions with small orifices<\/li>\n<\/ul>\n<h2>Hydraulic effects: Flow rate, pressure drop, and working speed<\/h2>\n<p>An undersized hose bore increases flow velocity. This leads to higher pressure losses, heating of the oil, potential cavitation effects, and noticeable performance losses. With tools such as concrete demolition shears or hydraulic wedge splitters for rock and concrete, this manifests in longer cycle times, reduced responsiveness, and increased thermal load. Conversely, a sufficiently large bore lowers flow velocity and thus friction losses &#8211; the system runs cooler, quieter, and more efficiently. Sizing is therefore always a trade-off between the desired speed, the available delivery rate of the power pack, the permissible pressure drop, and practical hose dimensions. In general, pressure drop scales strongly with velocity in the turbulent regime common to hydraulics, so even modest diameter increases can meaningfully reduce losses.<\/p>\n<h3>Key influencing factors<\/h3>\n<ul>\n<li>Flow rate of the hydraulic power pack<\/li>\n<li>Viscosity and temperature of the hydraulic oil<\/li>\n<li>Line length, number of bends and fittings<\/li>\n<li>Inner surface quality and restrictions in couplings<\/li>\n<li>Permissible flow velocity by line type (pressure, return, suction)<\/li>\n<li>Pulsation level and load changes over the duty cycle<\/li>\n<li>Cleanliness state and filter loading over service life<\/li>\n<\/ul>\n<h2>Sizing in concrete demolition, special demolition, and rock excavation<\/h2>\n<p>In mobile hydraulic applications by Darda GmbH &#8211; from concrete demolition shears to Multi Cutters and hydraulic wedge splitters &#8211; the hose bore is selected so that the desired tool speed is achieved without thermally overloading the system. For pressure lines, flow velocities of roughly 3 to 5 m\/s are often targeted; return lines are typically lower, suction lines lower still (often well below 2 m\/s to avoid inlet issues). These ranges are practical guidelines and can vary depending on the characteristics of <a href=\"https:\/\/www.darda.de\/en\/product-overview\/hydraulic-power-units\">Darda hydraulic power units<\/a>, oil temperature, and line length. Especially with long supply lines in <em>tunnel construction<\/em> or when there is significant spatial distance between the <em>hydraulic power pack<\/em> and the tool, a larger hose bore is recommended to limit pressure drop and keep tool response stable.<\/p>\n<p><strong>Example calculation:<\/strong> For Q = 20 l\/min (0.000333 m\u00b3\/s) and a target velocity v = 4 m\/s, the required area is A = Q\/v = 8.33e-5 m\u00b2, giving an inner diameter d \u2248 10.3 mm. For Q = 30 l\/min at the same velocity, d rises to about 12.6 mm. In practice, select the next available hose and coupling sizes with at least this through-bore.<\/p>\n<h3>Relation to concrete demolition shears and hydraulic wedge splitters<\/h3>\n<p>With concrete demolition shears, the hose bore directly affects the closing and opening speed of the shear. Bottlenecks &#8211; such as in plug-in couplings &#8211; can noticeably extend cycle time and promote heat build-up. For hydraulic wedge splitters for rock and concrete, a sufficient cross-section is crucial so the required pressure builds quickly and the splitting process starts without delay. In both cases, a well-matched hose bore improves controllability, reduces noise, and stabilizes process quality in daily deconstruction work. Undersized return lines can also elevate back pressure, which slows opening strokes and raises oil temperature.<\/p>\n<h2>Installation and operation: Bend radii, lengths, and couplings<\/h2>\n<p>Beyond the bore itself, routing and attached components also affect flow. Bend radii that are too tight cause internal cross-section constrictions that increase pressure drop. Likewise, multiple elbows or reducers in series generate additional turbulence. Clean, stress-free routing with few changes of direction and properly sized couplings is therefore critical for low-loss operation. Consistent clamping and support prevent vibration-induced wear and minimize micro-leakage at fittings.<\/p>\n<ul>\n<li>Observe minimum bend radius and avoid torsion<\/li>\n<li>Reduce unnecessary chains of adapters and tight 90\u00b0 elbows<\/li>\n<li>Select couplings with sufficient through-bore<\/li>\n<li>Limit line lengths to what is necessary<\/li>\n<li>Ensure protection against abrasion and crushing<\/li>\n<\/ul>\n<h2>Common symptoms of an unsuitable hose bore<\/h2>\n<p>If a hydraulic tool moves slowly despite adequate power pack pressure, the hose bore &#8211; or a constriction somewhere in the line &#8211; is a typical checkpoint. Indicators include elevated oil temperatures, noticeable heating of individual fittings, flow-related noises, and delayed response under load changes. In practice, quick couplings and adapters are checked first, followed by an assessment of hose lengths and bend radii. With concrete demolition shears, the effect can be observed directly in the change of closing times after the bottleneck is removed.<\/p>\n<ul>\n<li>Compare measured cycle times with specification or baseline values<\/li>\n<li>Use an IR thermometer on couplings\/fittings to identify hot spots<\/li>\n<li>Check return line back pressure during rapid opening strokes<\/li>\n<\/ul>\n<h2>Step-by-step sizing of the hose bore<\/h2>\n<ol>\n<li>Determine the flow rate and operating mode of the hydraulic power pack.<\/li>\n<li>Define target flow velocities for pressure, return, and suction lines (use practical ranges).<\/li>\n<li>Calculate inner \u00d8: From flow rate and desired velocity, derive the required cross-sectional area and thus the inner \u00d8.<\/li>\n<li>Consider the complete line: couplings, valves, elbows, reducers &#8211; the smallest through-bore must not unduly limit the cross-section.<\/li>\n<li>Conduct a practical test under typical operating conditions (temperature, line length, load changes) and adjust the bore if necessary.<\/li>\n<li>Verify thermal behavior at steady state and under peak load; confirm that oil temperature and cycle times remain within target limits.<\/li>\n<\/ol>\n<h2>Influence of operating conditions<\/h2>\n<p>Oil temperature and viscosity change over the day and with the ambient conditions. Cold increases viscosity and thereby pressure drop; for long lines, a larger hose bore is worthwhile for stable start-up and transition phases. In <em>tunnel construction<\/em> and <em>natural stone extraction<\/em>, greater distances are common &#8211; damping pressure peaks and avoiding local bottlenecks is particularly important here. In building gutting and cutting, where equipment is frequently repositioned, robust <em>quick couplings<\/em> with sufficient through-bore are useful to ensure repeated coupling without performance loss. In special operations with confined space, careful routing while maintaining the bend radius helps avoid cross-section losses.<\/p>\n<h2>Materials, media, and temperature range<\/h2>\n<p>The inner materials of hydraulic hoses must be compatible with the oil used. Temperature ranges, additives, and any rapidly biodegradable media influence swelling behavior and aging. A resistant inner layer supports long-lasting flow characteristics &#8211; worn or damaged inner layers can cause delamination that reduces the effective cross-section and loads the filters. Media-compatible materials and regular visual inspections are essential for stable operating values of the hose bore. Where biodegradable media are used, observe reduced lifetime and adjust inspection intervals accordingly.<\/p>\n<h2>Maintenance and replacement<\/h2>\n<p>The hose bore is effective only if the line is in good technical condition. Regular checks for abrasion, pinch points, leaks, and coupling wear are part of safe operation. O-rings and sealing cones in couplings should be renewed as needed to prevent internal restrictions from damaged seals. Condition-based or time-based hose replacement supports consistent flow conditions and reduces unplanned downtime in day-to-day <em>deconstruction<\/em>. After any replacement, perform cleanliness checks and pressure testing to confirm correct assembly and flow capacity.<\/p>\n<h2>Practical notes for tools from Darda GmbH<\/h2>\n<p>For concrete demolition shears, a sufficiently large return line pays off to minimize back pressure and speed up the opening movement. For hydraulic wedge splitters for rock and concrete, a harmonized cross-section of pressure line, return line, and <em>quick coupling<\/em> pairs leads to rapid pressure build-up at the splitting cylinder. The same applies to combination shears, Multi Cutters, steel shears, and tank cutters: A balanced hose bore along the entire line increases process stability, reduces heating, and supports precise controllability &#8211; especially under repeated load changes and varying ambient conditions. Matching the through-bore of couplings to the selected hose ID avoids hidden bottlenecks.<\/p>\n<h2>Safety and general notes<\/h2>\n<p>Hoses and fittings should be rated for the intended operating pressure with an appropriate safety factor. Damaged lines must be taken out of service immediately and replaced properly. Work on pressure lines is performed de-energized and clean; contamination inside must be avoided, as it narrows flow cross-sections and can impair components. In general, it is advisable to follow recognized engineering standards and manufacturer specifications. These notes are general in nature. If accumulators are present, discharge them safely before any intervention and verify zero pressure prior to opening connections.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>The hose bore is a central parameter in the hydraulics of demolition and cutting technology. It largely determines how much fluid a hose and its connection components can safely transport per unit of time. In Darda GmbH applications &#8211; such as hydraulic rock and concrete splitters, concrete demolition shears, combination <a class=\"moretag\" href=\"https:\/\/www.darda.de\/en\/knowledge\/hose-bore\">read more&#8230;<\/a><\/p>\n","protected":false},"author":9,"featured_media":0,"parent":14846,"menu_order":0,"comment_status":"open","ping_status":"open","template":"tmpl\/template-wissen.php","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-19740","page","type-page","status-publish","hentry"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Hose Bore - Hydraulic Inner Diameter &amp; Sizing<\/title>\n<meta name=\"description\" content=\"Master hose bore in hydraulics \u2713 Learn inner diameter, flow, pressure drop &amp; sizing for faster, cooler tools.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.darda.de\/en\/knowledge\/hose-bore\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Hose Bore - Hydraulic Inner Diameter &amp; Sizing\" \/>\n<meta property=\"og:description\" content=\"Master hose bore in hydraulics \u2713 Learn inner diameter, flow, pressure drop &amp; sizing for faster, cooler tools.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.darda.de\/en\/knowledge\/hose-bore\" \/>\n<meta property=\"og:site_name\" content=\"Darda GmbH\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/DardaDemolition\" \/>\n<meta property=\"article:modified_time\" content=\"2026-05-18T10:32:02+00:00\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"9 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.darda.de\\\/en\\\/knowledge\\\/hose-bore\",\"url\":\"https:\\\/\\\/www.darda.de\\\/en\\\/knowledge\\\/hose-bore\",\"name\":\"Hose Bore - Hydraulic Inner Diameter & Sizing\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.darda.de\\\/en#website\"},\"datePublished\":\"2025-12-12T14:52:56+00:00\",\"dateModified\":\"2026-05-18T10:32:02+00:00\",\"description\":\"Master hose bore in hydraulics \u2713 Learn inner diameter, flow, pressure drop & sizing for faster, cooler tools.\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/www.darda.de\\\/en\\\/knowledge\\\/hose-bore#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/www.darda.de\\\/en\\\/knowledge\\\/hose-bore\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/www.darda.de\\\/en\\\/knowledge\\\/hose-bore#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/www.darda.de\\\/en\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Knowledge\",\"item\":\"https:\\\/\\\/www.darda.de\\\/en\\\/knowledge\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Hose bore\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/www.darda.de\\\/en#website\",\"url\":\"https:\\\/\\\/www.darda.de\\\/en\",\"name\":\"Darda GmbH\",\"description\":\"\",\"publisher\":{\"@id\":\"https:\\\/\\\/www.darda.de\\\/en#organization\"},\"alternateName\":\"Abbruchwerkzeuge\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/www.darda.de\\\/en?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/www.darda.de\\\/en#organization\",\"name\":\"Darda GmbH\",\"url\":\"https:\\\/\\\/www.darda.de\\\/en\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/www.darda.de\\\/en#\\\/schema\\\/logo\\\/image\\\/\",\"url\":\"https:\\\/\\\/www.darda.de\\\/wp-content\\\/uploads\\\/2017\\\/09\\\/android-icon-192x192-1.png\",\"contentUrl\":\"https:\\\/\\\/www.darda.de\\\/wp-content\\\/uploads\\\/2017\\\/09\\\/android-icon-192x192-1.png\",\"width\":192,\"height\":192,\"caption\":\"Darda GmbH\"},\"image\":{\"@id\":\"https:\\\/\\\/www.darda.de\\\/en#\\\/schema\\\/logo\\\/image\\\/\"},\"sameAs\":[\"https:\\\/\\\/www.facebook.com\\\/DardaDemolition\",\"https:\\\/\\\/www.instagram.com\\\/darda_demolition\",\"https:\\\/\\\/www.youtube.com\\\/user\\\/DardaGmbH\",\"https:\\\/\\\/www.xing.com\\\/pages\\\/darda-gmbh\",\"https:\\\/\\\/de.linkedin.com\\\/company\\\/darda-gmbh\"]}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Hose Bore - Hydraulic Inner Diameter & Sizing","description":"Master hose bore in hydraulics \u2713 Learn inner diameter, flow, pressure drop & sizing for faster, cooler tools.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.darda.de\/en\/knowledge\/hose-bore","og_locale":"en_US","og_type":"article","og_title":"Hose Bore - Hydraulic Inner Diameter & Sizing","og_description":"Master hose bore in hydraulics \u2713 Learn inner diameter, flow, pressure drop & sizing for faster, cooler tools.","og_url":"https:\/\/www.darda.de\/en\/knowledge\/hose-bore","og_site_name":"Darda GmbH","article_publisher":"https:\/\/www.facebook.com\/DardaDemolition","article_modified_time":"2026-05-18T10:32:02+00:00","twitter_card":"summary_large_image","twitter_misc":{"Est. reading time":"9 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.darda.de\/en\/knowledge\/hose-bore","url":"https:\/\/www.darda.de\/en\/knowledge\/hose-bore","name":"Hose Bore - Hydraulic Inner Diameter & Sizing","isPartOf":{"@id":"https:\/\/www.darda.de\/en#website"},"datePublished":"2025-12-12T14:52:56+00:00","dateModified":"2026-05-18T10:32:02+00:00","description":"Master hose bore in hydraulics \u2713 Learn inner diameter, flow, pressure drop & sizing for faster, cooler tools.","breadcrumb":{"@id":"https:\/\/www.darda.de\/en\/knowledge\/hose-bore#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.darda.de\/en\/knowledge\/hose-bore"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/www.darda.de\/en\/knowledge\/hose-bore#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.darda.de\/en"},{"@type":"ListItem","position":2,"name":"Knowledge","item":"https:\/\/www.darda.de\/en\/knowledge"},{"@type":"ListItem","position":3,"name":"Hose bore"}]},{"@type":"WebSite","@id":"https:\/\/www.darda.de\/en#website","url":"https:\/\/www.darda.de\/en","name":"Darda GmbH","description":"","publisher":{"@id":"https:\/\/www.darda.de\/en#organization"},"alternateName":"Abbruchwerkzeuge","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.darda.de\/en?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/www.darda.de\/en#organization","name":"Darda GmbH","url":"https:\/\/www.darda.de\/en","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.darda.de\/en#\/schema\/logo\/image\/","url":"https:\/\/www.darda.de\/wp-content\/uploads\/2017\/09\/android-icon-192x192-1.png","contentUrl":"https:\/\/www.darda.de\/wp-content\/uploads\/2017\/09\/android-icon-192x192-1.png","width":192,"height":192,"caption":"Darda GmbH"},"image":{"@id":"https:\/\/www.darda.de\/en#\/schema\/logo\/image\/"},"sameAs":["https:\/\/www.facebook.com\/DardaDemolition","https:\/\/www.instagram.com\/darda_demolition","https:\/\/www.youtube.com\/user\/DardaGmbH","https:\/\/www.xing.com\/pages\/darda-gmbh","https:\/\/de.linkedin.com\/company\/darda-gmbh"]}]}},"_links":{"self":[{"href":"https:\/\/www.darda.de\/en\/wp-json\/wp\/v2\/pages\/19740","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.darda.de\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.darda.de\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.darda.de\/en\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/www.darda.de\/en\/wp-json\/wp\/v2\/comments?post=19740"}],"version-history":[{"count":2,"href":"https:\/\/www.darda.de\/en\/wp-json\/wp\/v2\/pages\/19740\/revisions"}],"predecessor-version":[{"id":27535,"href":"https:\/\/www.darda.de\/en\/wp-json\/wp\/v2\/pages\/19740\/revisions\/27535"}],"up":[{"embeddable":true,"href":"https:\/\/www.darda.de\/en\/wp-json\/wp\/v2\/pages\/14846"}],"wp:attachment":[{"href":"https:\/\/www.darda.de\/en\/wp-json\/wp\/v2\/media?parent=19740"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}