{"id":6654,"date":"2026-07-17T17:04:07","date_gmt":"2026-07-17T17:04:07","guid":{"rendered":"https:\/\/europascal.de\/product\/flule-calibration-molbloc-s\/"},"modified":"2026-10-01T09:57:47","modified_gmt":"2026-10-01T09:57:47","slug":"fluke-calibration-molbloc-s","status":"publish","type":"product","link":"https:\/\/europascal.de\/en\/product\/fluke-calibration-molbloc-s\/","title":{"rendered":"Fluke Calibration molbloc-S Precise Sonic Nozzle Flow Element"},"content":{"rendered":"<p><strong>Fluke Calibration molbloc-S<\/strong> is a precise sonic nozzle flow element designed for professional gas mass flow measurement and calibration. Used together with a compatible Fluke Calibration molbox flow terminal, the molbloc-S provides a highly stable reference for calibrating gas flow meters, mass flow meters and mass flow controllers at medium and high gas flow rates.<\/p>\n<p>The molbloc-S operates according to the proven <strong>critical flow venturi or sonic nozzle principle<\/strong>. When the required pressure ratio across the nozzle is reached, the gas reaches sonic velocity at the nozzle throat. Under these choked-flow conditions, the mass flow rate is primarily determined by the upstream absolute pressure, gas temperature, nozzle characteristics and gas properties.<\/p>\n<p>This operating principle provides excellent stability and repeatability while minimizing sensitivity to downstream pressure variations within the permitted critical-flow operating range.<\/p>\n<p>Depending on the selected molbloc-S size and operating pressure, the system can cover gas flows extending up to approximately <strong>5,000 slm<\/strong> for air and nitrogen applications. Different molbloc-S sizes can be connected to the same compatible molbox flow terminal, creating a modular calibration system that can be adapted to different flow ranges.<\/p>\n<p>With Premium calibration, the molbloc-S system provides a measurement uncertainty as low as <strong>\u00b10.125% of reading<\/strong>, making it suitable for demanding calibration laboratories, industrial metrology and research applications.<\/p>\n<p>At <strong>europascal<\/strong>, the Fluke Calibration molbloc-S complements a comprehensive range of professional flow and calibration equipment. For information about professional calibration and metrological traceability, visit the <a href=\"https:\/\/europascal.de\/en\/calibration-services\/\">europascal Calibration Service<\/a>.<\/p>\n<h2>Your Benefits at a Glance<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> combines the proven sonic nozzle measurement principle with high accuracy, excellent stability and flexible integration into molbloc\/molbox calibration systems.<\/p>\n<p>Key advantages include:<\/p>\n<ul>\n<li>Sonic nozzle flow element for gas mass flow calibration<\/li>\n<li>Proven critical-flow Venturi nozzle principle<\/li>\n<li>Gas flow capability up to approximately 5,000 slm depending on model and operating conditions<\/li>\n<li>Measurement uncertainty down to \u00b10.125% of reading with Premium calibration<\/li>\n<li>Standard calibration uncertainty of \u00b10.2% of reading<\/li>\n<li>Precision of \u00b10.06% of reading<\/li>\n<li>Resolution of 0.0015% FS<\/li>\n<li>Excellent long-term stability<\/li>\n<li>Usable range from 10% to 100% of full scale<\/li>\n<li>Up to 10:1 turndown with appropriate molbox configuration<\/li>\n<li>Integral gas temperature conditioning and measurement<\/li>\n<li>Multiple calibration gases available<\/li>\n<li>Low sensitivity to contamination<\/li>\n<li>No moving parts<\/li>\n<li>Continuous real-time flow measurement<\/li>\n<li>Multiple pressure calibration ranges<\/li>\n<li>Can be fully automated<\/li>\n<li>Compatible with Fluke Calibration molbox flow terminals<\/li>\n<li>Compatible with molbox2 and molbox2-S systems<\/li>\n<li>Integration with COMPASS for Flow software<\/li>\n<li>Accredited calibration report included with standard configurations<\/li>\n<\/ul>\n<h2>Critical Flow Sonic Nozzle Principle<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> uses a critical-flow Venturi nozzle as its fundamental measurement element.<\/p>\n<p>Gas enters the nozzle from the upstream side and accelerates as the cross-sectional area decreases.<\/p>\n<p>At the narrowest point of the nozzle, known as the throat, the gas can reach:<\/p>\n<p><strong>Mach 1<\/strong><\/p>\n<p>or sonic velocity.<\/p>\n<p>When this condition is reached, the flow is described as:<\/p>\n<p><strong>critical flow<\/strong><\/p>\n<p>or:<\/p>\n<p><strong>choked flow<\/strong>.<\/p>\n<p>Once the flow is choked, further reductions in downstream pressure do not significantly increase the mass flow through the nozzle.<\/p>\n<p>The mass flow is then primarily determined by:<\/p>\n<ul>\n<li>Upstream absolute pressure<\/li>\n<li>Gas temperature<\/li>\n<li>Nozzle geometry<\/li>\n<li>Gas properties<\/li>\n<\/ul>\n<p>This makes the sonic nozzle an excellent transfer standard for gas mass flow calibration.<\/p>\n<h2>Mass Flow Proportional to Upstream Pressure<\/h2>\n<p>Under critical-flow conditions, the mass flow through a molbloc-S is approximately proportional to the absolute upstream pressure.<\/p>\n<p>Fluke characterizes each molbloc-S using a:<\/p>\n<p><strong>Pressure to Flow Conversion Ratio KF<\/strong>.<\/p>\n<p>The KF value describes the relationship between upstream pressure and mass flow.<\/p>\n<p>Different molbloc-S models provide different KF values.<\/p>\n<p>This enables the appropriate sonic nozzle element to be selected according to the required flow range.<\/p>\n<p>By changing the upstream pressure, the user can vary the mass flow through the molbloc-S while maintaining critical-flow conditions.<\/p>\n<h2>Flow Rates up to Approximately 5,000 slm<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> family is designed to cover medium to high gas flow rates.<\/p>\n<p>Depending on nozzle size, calibration range, gas and operating pressure, molbloc-S elements can cover flow rates extending to approximately:<\/p>\n<p><strong>5,000 slm<\/strong><\/p>\n<p>for nitrogen and air.<\/p>\n<p>This complements the lower-flow capability of Fluke Calibration molbloc-L laminar flow elements.<\/p>\n<p>A complete molbloc\/molbox system can therefore cover an exceptionally broad range of gas flows using interchangeable flow elements.<\/p>\n<h2>10:1 Rangeability<\/h2>\n<p>A major advantage of the <strong>Fluke Calibration molbloc-S<\/strong> is its potential rangeability.<\/p>\n<p>The specified flow measurement range is:<\/p>\n<p><strong>10% to 100% of molbloc full scale<\/strong>.<\/p>\n<p>This corresponds to a potential:<\/p>\n<p><strong>10:1 turndown<\/strong>.<\/p>\n<p>The achievable range depends on the available upstream pressure and required downstream-to-upstream pressure ratio.<\/p>\n<p>When combined with a suitable high-pressure molbox2-S configuration, a molbloc-S can cover a particularly broad flow range without requiring a vacuum pump in many common applications.<\/p>\n<h2>Measurement Uncertainty Down to \u00b10.125%<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> provides excellent measurement performance for professional gas flow calibration.<\/p>\n<p>With Standard calibration, Fluke specifies measurement uncertainty of:<\/p>\n<p><strong>\u00b10.2% of reading<\/strong>.<\/p>\n<p>With Premium calibration, this improves to:<\/p>\n<p><strong>\u00b10.125% of reading<\/strong>.<\/p>\n<p>The specified precision is:<\/p>\n<p><strong>\u00b10.06% of reading<\/strong>.<\/p>\n<p>Resolution is:<\/p>\n<p><strong>0.0015% of full scale<\/strong>.<\/p>\n<p>These specifications apply over the specified 10% to 100% full-scale operating range and under the corresponding calibration and operating conditions.<\/p>\n<h2>Excellent Long-Term Stability<\/h2>\n<p>The sonic nozzle principle provides excellent long-term stability because the molbloc-S contains no moving measurement components.<\/p>\n<p>For Standard calibration, Fluke specifies predicted one-year stability of:<\/p>\n<p><strong>\u00b10.05% of reading<\/strong>.<\/p>\n<p>With Premium calibration, the corresponding value is:<\/p>\n<p><strong>\u00b10.03% of reading<\/strong>.<\/p>\n<p>This stability is an important characteristic for calibration laboratories because long-term changes in the reference standard directly influence calibration results and measurement uncertainty.<\/p>\n<h2>molbloc-S with Fluke Calibration molbox2<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> is designed to operate as part of the molbloc\/molbox gas flow calibration system.<\/p>\n<p>A modern configuration consists of:<\/p>\n<p><strong>molbloc-S + Fluke Calibration molbox2<\/strong><\/p>\n<p>The molbloc-S provides the characterized sonic nozzle flow element.<\/p>\n<p>The molbox2 measures the upstream absolute pressure and temperature required for determining the gas mass flow.<\/p>\n<p>The calibration data stored for the molbloc is then used by the flow terminal to calculate and display the corresponding flow value in real time.<\/p>\n<p>This modular design enables different molbloc flow elements to be connected to the same molbox terminal.<\/p>\n<h2>molbloc-S with molbox2-S<\/h2>\n<p>For maximum rangeability, the <strong>Fluke Calibration molbloc-S<\/strong> can be combined with the special:<\/p>\n<p><strong>molbox2-S<\/strong><\/p>\n<p>flow terminal configuration.<\/p>\n<p>The molbox2-S is specifically optimized for sonic nozzle applications.<\/p>\n<p>It is available with upstream Q-RPT pressure measurement up to:<\/p>\n<p><strong>2 MPa absolute \/ 300 psia<\/strong>.<\/p>\n<p>The higher upstream pressure capability allows the molbloc-S to operate over a wider flow range when positioned upstream of a device under test operating near atmospheric pressure.<\/p>\n<p>This can provide a full:<\/p>\n<p><strong>10:1 flow turndown<\/strong><\/p>\n<p>without requiring a vacuum pump in many applications.<\/p>\n<h2>Example of Extended Rangeability<\/h2>\n<p>Fluke provides practical examples showing the benefit of combining molbloc-S with molbox2-S.<\/p>\n<p>For example, a:<\/p>\n<p><strong>1E2-S<\/strong><\/p>\n<p>molbloc-S may provide approximately:<\/p>\n<p><strong>15 to 60 slm<\/strong><\/p>\n<p>with a Standard Pressure calibration and molbox2 A700K when the device under test operates at atmospheric pressure.<\/p>\n<p>With a High Pressure calibration and molbox2-S A2M, the usable range can increase to approximately:<\/p>\n<p><strong>20 to 300 slm<\/strong>.<\/p>\n<p>For a:<\/p>\n<p><strong>5E2-S<\/strong><\/p>\n<p>element, a typical Standard Pressure configuration provides approximately:<\/p>\n<p><strong>67 to 300 slm<\/strong>.<\/p>\n<p>With High Pressure calibration and molbox2-S, the usable range can extend to approximately:<\/p>\n<p><strong>100 to 1,000 slm<\/strong>.<\/p>\n<p>This expanded rangeability can reduce the number of flow elements required to cover a broad calibration range.<\/p>\n<h2>Multiple Pressure Calibration Ranges<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> can be calibrated for different upstream pressure ranges.<\/p>\n<p>Fluke defines three primary pressure calibration ranges.<\/p>\n<p><strong>Low Pressure \u2013 LP<\/strong><\/p>\n<p>Upstream absolute pressure:<\/p>\n<p><strong>20 to 200 kPa absolute<\/strong><\/p>\n<p><strong>Standard Pressure \u2013 SP<\/strong><\/p>\n<p>Upstream absolute pressure:<\/p>\n<p><strong>50 to 500 kPa absolute<\/strong><\/p>\n<p><strong>High Pressure \u2013 HP<\/strong><\/p>\n<p>Upstream absolute pressure:<\/p>\n<p><strong>200 kPa to 2 MPa absolute<\/strong><\/p>\n<p>The appropriate calibration range depends on the required flow range, system configuration and position of the device under test.<\/p>\n<p>Multiple calibration types can be stored for the same molbloc-S, providing additional flexibility.<\/p>\n<h2>Required Back Pressure Ratio<\/h2>\n<p>For a sonic nozzle to operate under critical-flow conditions, a sufficient pressure ratio must exist between the upstream and downstream sides.<\/p>\n<p>Fluke specifies a required back-pressure ratio of approximately:<\/p>\n<p><strong>0.4 to 0.9<\/strong><\/p>\n<p>depending on Reynolds number.<\/p>\n<p>The exact critical pressure ratio depends on operating conditions.<\/p>\n<p>If the downstream pressure becomes too high relative to the upstream pressure, the nozzle leaves the critical-flow condition.<\/p>\n<p>Correct system design must therefore ensure that the required pressure ratio is maintained throughout the intended flow range.<\/p>\n<h2>Integral Gas Temperature Conditioning<\/h2>\n<p>Accurate gas temperature measurement is essential for determining mass flow through a sonic nozzle.<\/p>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> therefore incorporates gas temperature conditioning and measurement.<\/p>\n<p>The molbox terminal reads the temperature information together with the upstream pressure.<\/p>\n<p>These parameters are combined with the molbloc calibration data and gas properties to determine the mass flow.<\/p>\n<p>This integrated approach supports accurate real-time flow measurement.<\/p>\n<h2>Multiple Calibration Gases<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> can be calibrated for several gases.<\/p>\n<p>Standard calibration is performed using:<\/p>\n<p><strong>dry air<\/strong>.<\/p>\n<p>Optional calibration gases include:<\/p>\n<ul>\n<li>Nitrogen \u2013 N\u2082<\/li>\n<li>Argon \u2013 Ar<\/li>\n<li>Hydrogen \u2013 H\u2082<\/li>\n<li>Helium \u2013 He<\/li>\n<li>Nitrous oxide \u2013 N\u2082O<\/li>\n<\/ul>\n<p>Additional gases may be available depending on molbloc size and calibration range.<\/p>\n<p>Fluke recommends consultation regarding the availability of specific gas and range combinations.<\/p>\n<p>A dry-air calibration is required for humid-air operation.<\/p>\n<h2>Real-Time Gas Flow Measurement<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> provides continuous real-time flow measurement when used with a compatible molbox terminal.<\/p>\n<p>This is a major practical advantage compared with flow standards that require gas to be collected over a defined time interval.<\/p>\n<p>The operator can directly observe how the device under test responds to changes in gas flow.<\/p>\n<p>This is particularly useful when calibrating:<\/p>\n<ul>\n<li>Mass flow controllers<\/li>\n<li>Mass flow meters<\/li>\n<li>Rotameters<\/li>\n<li>Variable-area flow meters<\/li>\n<li>Turbine gas meters<\/li>\n<li>Process flow instruments<\/li>\n<\/ul>\n<p>Real-time measurement also simplifies adjustment of analog flow devices.<\/p>\n<h2>Calibration of Mass Flow Controllers<\/h2>\n<p>One of the most important applications of the <strong>Fluke Calibration molbloc-S<\/strong> is calibration of mass flow controllers.<\/p>\n<p>A typical system can consist of:<\/p>\n<p><strong>Gas Supply \u2192 molbloc-S \u2192 MFC Under Test<\/strong><\/p>\n<p>with the molbox terminal measuring the upstream conditions at the molbloc-S.<\/p>\n<p>The reference flow calculated by the molbox is compared with the indicated or commanded flow of the mass flow controller.<\/p>\n<p>Depending on the required system configuration, additional pressure regulation, valves and vacuum equipment may be used.<\/p>\n<p>With molbox2-S and a suitable high-pressure calibration, many applications can be performed without a downstream vacuum pump.<\/p>\n<h2>Calibration of Gas Flow Meters<\/h2>\n<p>The molbloc-S is also suitable for calibration of various gas flow meters.<\/p>\n<p>Typical devices include:<\/p>\n<ul>\n<li>Thermal mass flow meters<\/li>\n<li>Mass flow controllers<\/li>\n<li>Rotameters<\/li>\n<li>Variable-area flow meters<\/li>\n<li>Turbine gas meters<\/li>\n<li>Roots-type gas meters<\/li>\n<li>Critical flow devices<\/li>\n<li>Process gas flow meters<\/li>\n<li>Flow transfer standards<\/li>\n<\/ul>\n<p>The broad range of available molbloc-S sizes allows a calibration system to be configured for different flow requirements.<\/p>\n<h2>Minimal Sensitivity to Contamination<\/h2>\n<p>Sonic nozzle flow elements provide good resistance to contamination compared with measurement principles containing small laminar flow passages or moving components.<\/p>\n<p>Fluke highlights the molbloc-S as having:<\/p>\n<p><strong>minimal sensitivity to contamination<\/strong>.<\/p>\n<p>Nevertheless, clean calibration gas should always be used.<\/p>\n<p>Contamination or physical damage to the nozzle geometry can influence the relationship between upstream conditions and mass flow and therefore affect calibration performance.<\/p>\n<p>Appropriate filtration and careful handling remain important for maintaining metrological performance.<\/p>\n<h2>No Moving Parts<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> contains no moving measurement parts.<\/p>\n<p>This provides several advantages:<\/p>\n<ul>\n<li>Excellent repeatability<\/li>\n<li>High reliability<\/li>\n<li>Low mechanical wear<\/li>\n<li>No mechanical flow fluctuations<\/li>\n<li>Excellent long-term stability<\/li>\n<li>Reduced maintenance requirements<\/li>\n<\/ul>\n<p>This simple and stable measurement principle is particularly valuable for reference standards used repeatedly in professional calibration laboratories.<\/p>\n<h2>Traceability to Gravimetric Flow Standards<\/h2>\n<p>The performance of the molbloc-S is supported by primary gravimetric calibration.<\/p>\n<p>Fluke Calibration uses gravimetric mass flow measurement as the basis for establishing traceability of its molbloc flow elements.<\/p>\n<p>This provides the metrological foundation for using molbloc-S elements as transfer standards in professional gas flow calibration systems.<\/p>\n<h2>Accredited Calibration Report<\/h2>\n<p>A new <strong>Fluke Calibration molbloc-S<\/strong> is supplied with a standard uncertainty calibration at Standard Pressure using air and an accredited calibration report.<\/p>\n<p>Premium uncertainty calibration is available as an option.<\/p>\n<p>Low Pressure and High Pressure calibrations are also available according to the required application.<\/p>\n<p>Additional gas calibrations can be ordered depending on the selected model and operating range.<\/p>\n<p>This enables the molbloc-S to be configured specifically for the intended calibration task.<\/p>\n<h2>molbloc-S Models<\/h2>\n<p>Fluke offers several molbloc-S sizes with different pressure-to-flow conversion ratios.<\/p>\n<p>Examples include:<\/p>\n<p><strong>1E1-S \u2013 KF 10 sccm\/kPa<\/strong><\/p>\n<p><strong>2E1-S \u2013 KF 20 sccm\/kPa<\/strong><\/p>\n<p><strong>5E1-S \u2013 KF 50 sccm\/kPa<\/strong><\/p>\n<p><strong>1E2-S \u2013 KF 100 sccm\/kPa<\/strong><\/p>\n<p>Additional sizes are available for higher flow ranges.<\/p>\n<p>The correct molbloc-S should be selected according to:<\/p>\n<ul>\n<li>Required minimum flow<\/li>\n<li>Required maximum flow<\/li>\n<li>Gas<\/li>\n<li>Upstream pressure<\/li>\n<li>Downstream pressure<\/li>\n<li>Required calibration uncertainty<\/li>\n<li>Device-under-test pressure requirements<\/li>\n<\/ul>\n<h2>molbloc-S vs. molbloc-L<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> and molbloc-L are both interchangeable flow elements for the molbloc\/molbox gas flow calibration system, but they use different measurement principles.<\/p>\n<p>The <strong>molbloc-S<\/strong> uses a:<\/p>\n<p><strong>critical-flow sonic nozzle<\/strong>.<\/p>\n<p>The <strong>molbloc-L<\/strong> uses a:<\/p>\n<p><strong>laminar flow element<\/strong>.<\/p>\n<p>molbloc-L is particularly suitable for lower flow rates and provides continuous operation down to very low percentages of full scale.<\/p>\n<p>molbloc-S is optimized for medium and higher gas flows and operates over approximately:<\/p>\n<p><strong>10% to 100% FS<\/strong>.<\/p>\n<p>The molbloc-S family extends the molbloc\/molbox system into flow ranges up to approximately:<\/p>\n<p><strong>5,000 slm<\/strong>.<\/p>\n<p>Both technologies can be used within the same overall Fluke Calibration flow calibration platform.<\/p>\n<h2>molbloc-S vs. Critical Nozzle<\/h2>\n<p>The molbloc-S is fundamentally a precision <strong>critical-flow Venturi nozzle<\/strong>, often also called a sonic nozzle.<\/p>\n<p>However, it is more than an uncharacterized nozzle.<\/p>\n<p>Each molbloc-S is individually calibrated and contains the information required by the compatible molbox terminal to determine mass flow from the measured operating conditions.<\/p>\n<p>The combination of characterized nozzle, integrated temperature measurement, pressure measurement and molbox calculation transforms the sonic nozzle into a professional gas flow transfer standard.<\/p>\n<h2>COMPASS for Flow Automation<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> can be integrated into automated calibration systems using:<\/p>\n<p><strong>COMPASS for Flow<\/strong>.<\/p>\n<p>The software supports automated gas flow calibration procedures in combination with compatible Fluke Calibration hardware.<\/p>\n<p>Depending on system configuration, automation can include:<\/p>\n<ul>\n<li>Flow point generation<\/li>\n<li>Pressure control<\/li>\n<li>Reference flow measurement<\/li>\n<li>Device-under-test measurement<\/li>\n<li>Calibration sequence execution<\/li>\n<li>Data acquisition<\/li>\n<li>Result processing<\/li>\n<li>Calibration documentation<\/li>\n<\/ul>\n<p>This makes molbloc-S suitable for both manually operated calibration benches and highly automated flow calibration laboratories.<\/p>\n<h2>Typical Applications<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> is suitable for:<\/p>\n<ul>\n<li>Gas mass flow calibration<\/li>\n<li>High gas flow calibration<\/li>\n<li>Mass flow controller calibration<\/li>\n<li>Mass flow meter calibration<\/li>\n<li>Rotameter calibration<\/li>\n<li>Variable-area flow meter calibration<\/li>\n<li>Turbine gas meter calibration<\/li>\n<li>Process flow meter calibration<\/li>\n<li>Sonic nozzle calibration systems<\/li>\n<li>Flow transfer standards<\/li>\n<li>Semiconductor applications<\/li>\n<li>Pharmaceutical applications<\/li>\n<li>Aerospace<\/li>\n<li>Environmental monitoring<\/li>\n<li>Energy applications<\/li>\n<li>Reference gas production<\/li>\n<li>Research laboratories<\/li>\n<li>Calibration laboratories<\/li>\n<li>Gas flow metrology<\/li>\n<\/ul>\n<h2>Why Choose the Fluke Calibration molbloc-S?<\/h2>\n<p>The <strong>Fluke Calibration molbloc-S<\/strong> combines the inherently stable sonic nozzle principle with individual characterization and integration into the proven Fluke Calibration molbloc\/molbox measurement system.<\/p>\n<p>The critical-flow operating principle makes the mass flow primarily dependent on upstream pressure, gas temperature, nozzle geometry and gas properties once sonic conditions have been established.<\/p>\n<p>With Premium calibration, measurement uncertainty can be as low as <strong>\u00b10.125% of reading<\/strong>, while precision is specified at <strong>\u00b10.06% of reading<\/strong>.<\/p>\n<p>The usable measurement range extends from <strong>10% to 100% of the individual molbloc full scale<\/strong>, providing up to <strong>10:1 turndown<\/strong> when suitable pressure conditions are available.<\/p>\n<p>Combined with the modern <strong>molbox2-S<\/strong>, molbloc-S elements can operate at upstream pressures up to 2 MPa absolute, significantly extending their usable flow range and reducing or eliminating the need for vacuum pumps in many calibration configurations.<\/p>\n<p>Multiple molbloc-S sizes and calibration pressure ranges allow the system to be adapted to specific gas flow applications.<\/p>\n<p>The result is a highly stable, modular and traceable gas flow standard suitable for demanding industrial and laboratory calibration.<\/p>\n<p>At <strong>europascal<\/strong>, we provide Fluke Calibration flow, pressure, temperature and electrical calibration technology for professional laboratory and industrial applications.<\/p>\n<p>For professional calibration and metrological traceability, visit the <a href=\"https:\/\/europascal.de\/en\/calibration-services\/\">europascal Calibration Service<\/a>.<\/p>\n<p>Further products from <strong>Fluke Calibration<\/strong> are available from europascal.<\/p>\n<p>Manufacturer information about the <strong>Fluke Calibration molbloc-S<\/strong> is available on the official Fluke Calibration website.<\/p>\n<p><a class=\"download-datasheet\" href=\"#\" data-pdf=\"https:\/\/europascal.de\/wp-content\/uploads\/2026\/07\/Fluke-molbloc-S-Sonic-Nozzle-Based-molblocs-for-Gas-Flow-up-to-5000-slm \/\/ Fluke-molbloc-S-ranges-with-high-pressure-standard-pressure-and-low-pressure-calibrations.pdf\"><span style=\"color: #0000ff;\"><strong><em>Download Datasheet<\/em><\/strong><\/span><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The <strong>Fluke Calibration molbloc-S<\/strong> is a precise sonic nozzle flow element for professional gas mass flow measurement and calibration. Based on the proven critical-flow Venturi principle, it provides excellent stability, real-time flow measurement and measurement uncertainty down to <strong>\u00b10.125% of reading<\/strong> with Premium calibration. Combined with molbox2 or molbox2-S, it creates a flexible reference system for gas flow meter and mass flow controller calibration.<\/p>\n","protected":false},"featured_media":3161,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center 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