{"id":6656,"date":"2026-07-17T17:04:10","date_gmt":"2026-07-17T17:04:10","guid":{"rendered":"https:\/\/europascal.de\/product\/fluke-calibration-molbloc-l\/"},"modified":"2026-10-01T10:03:44","modified_gmt":"2026-10-01T10:03:44","slug":"fluke-calibration-molbloc-l","status":"publish","type":"product","link":"https:\/\/europascal.de\/en\/product\/fluke-calibration-molbloc-l\/","title":{"rendered":"Fluke Calibration molbloc-L Precise Laminar Flow Element"},"content":{"rendered":"<p><strong>Fluke Calibration molbloc-L<\/strong> is a precise laminar flow element designed for professional gas mass flow measurement and calibration from approximately <strong>1 sccm to 100 slm<\/strong>. Combined with a compatible Fluke Calibration molbox flow terminal, the molbloc-L creates a highly accurate, stable and flexible reference system for calibrating gas flow meters, mass flow meters and mass flow controllers.<\/p>\n<p>The molbloc-L operates according to the laminar flow principle. Its precisely manufactured flow path consists of the annular gap between a piston and a closely fitted cylindrical bore inside the molbloc body. Gas flowing through this defined restriction produces a differential pressure that is related to the gas mass flow.<\/p>\n<p>Different molbloc-L models use different gap dimensions and body sizes to provide different flow ranges. Smaller flow paths are used for low gas flows, while larger molbloc bodies extend the system into higher flow ranges.<\/p>\n<p>Unlike mechanical flow meters, the Fluke Calibration molbloc-L contains no moving measurement parts. This provides excellent repeatability, long-term stability and low maintenance requirements.<\/p>\n<p>Combined with a molbox terminal such as the <strong>Fluke Calibration molbox2<\/strong>, the pressure and temperature conditions at the molbloc are measured and combined with the individual molbloc calibration data and gas properties to calculate the actual gas mass flow in real time.<\/p>\n<p>With Premium calibration, the system can achieve measurement uncertainty down to <strong>\u00b10.125% of reading from 10% to 100% FS<\/strong>, making the molbloc-L particularly suitable for demanding calibration laboratories, industrial metrology and research applications.<\/p>\n<p>At <strong>europascal<\/strong>, the Fluke Calibration molbloc-L complements a comprehensive range of professional gas flow calibration equipment. For 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-L<\/strong> combines the proven laminar flow principle with high measurement performance and the modular flexibility of the molbloc\/molbox calibration system.<\/p>\n<p>Key advantages include:<\/p>\n<ul>\n<li>Gas flow measurement from approximately 1 sccm to 100 slm<\/li>\n<li>Laminar flow measurement principle<\/li>\n<li>Precision down to \u00b10.07% of reading<\/li>\n<li>Measurement uncertainty down to \u00b10.125% of reading with Premium calibration<\/li>\n<li>Resolution of 0.0015% FS<\/li>\n<li>Continuous real-time flow measurement<\/li>\n<li>No moving parts<\/li>\n<li>Excellent repeatability<\/li>\n<li>Excellent long-term stability<\/li>\n<li>Integrated contamination filter<\/li>\n<li>Integral gas temperature conditioning<\/li>\n<li>Integrated gas temperature measurement<\/li>\n<li>Different molbloc sizes for different flow ranges<\/li>\n<li>Multiple operating pressure calibration options<\/li>\n<li>Different gas calibrations available<\/li>\n<li>Compatible with Fluke Calibration molbox flow terminals<\/li>\n<li>Compatible with molbox2<\/li>\n<li>Can be fully automated<\/li>\n<li>Compatible with COMPASS for Flow software<\/li>\n<li>Calibration report with measured calibration data<\/li>\n<li>Traceability to NIST<\/li>\n<li>Suitable for laboratory and industrial flow calibration<\/li>\n<\/ul>\n<h2>Gas Flow from 1 sccm to 100 slm<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> family covers gas flow rates from approximately:<\/p>\n<p><strong>1 sccm<\/strong><\/p>\n<p>to:<\/p>\n<p><strong>100 slm<\/strong>.<\/p>\n<p>This makes the molbloc-L particularly suitable for low and medium gas flow calibration.<\/p>\n<p>The actual operating range of an individual molbloc depends on several factors, including:<\/p>\n<ul>\n<li>molbloc size<\/li>\n<li>Gas type<\/li>\n<li>Gas density<\/li>\n<li>Gas viscosity<\/li>\n<li>Upstream pressure<\/li>\n<li>Differential pressure<\/li>\n<li>Operating pressure calibration<\/li>\n<\/ul>\n<p>The modular design allows several molbloc-L elements to be used with the same compatible molbox flow terminal.<\/p>\n<p>A calibration laboratory can therefore cover several decades of gas flow using a set of individually characterized molbloc-L elements.<\/p>\n<h2>Laminar Flow Measurement Principle<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> operates according to the laminar flow principle.<\/p>\n<p>Inside the molbloc is a precisely manufactured cylindrical flow path.<\/p>\n<p>Fluke describes the actual flow path as the:<\/p>\n<p><strong>gap between a piston and a close-fitting cylindrical bore in the molbloc body<\/strong>.<\/p>\n<p>Gas flows through this narrow annular gap.<\/p>\n<p>Under the specified operating conditions, the gas flow remains predominantly laminar.<\/p>\n<p>This means the gas moves in organized layers rather than the strongly mixed motion associated with turbulent flow.<\/p>\n<p>A differential pressure develops across the flow restriction.<\/p>\n<p>This differential pressure, together with gas pressure, temperature, gas properties and the individual calibration characteristics of the molbloc, allows the gas mass flow to be calculated.<\/p>\n<h2>Differential Pressure and Flow<\/h2>\n<p>The operating principle of a laminar flow element is based on the relationship between flow and pressure drop across a defined restriction.<\/p>\n<p>For a given molbloc-L, the differential pressure changes as the gas flow changes.<\/p>\n<p>The molbox terminal accurately measures this differential pressure.<\/p>\n<p>It also determines the relevant absolute pressure and the temperature of the molbloc.<\/p>\n<p>The complete flow calculation therefore considers more than differential pressure alone.<\/p>\n<p>Important input quantities include:<\/p>\n<ul>\n<li>Differential pressure<\/li>\n<li>Absolute pressure<\/li>\n<li>Gas temperature<\/li>\n<li>Gas type<\/li>\n<li>Gas viscosity<\/li>\n<li>Gas density<\/li>\n<li>Individual molbloc calibration coefficients<\/li>\n<\/ul>\n<p>This approach enables the molbloc-L to function as a high-performance gas mass flow transfer standard.<\/p>\n<h2>Different molbloc-L Sizes<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> is available in multiple sizes.<\/p>\n<p>Examples include:<\/p>\n<ul>\n<li>1E1<\/li>\n<li>5E1<\/li>\n<li>1E2<\/li>\n<li>2E2<\/li>\n<li>5E2<\/li>\n<li>1E3<\/li>\n<li>5E3<\/li>\n<li>1E4<\/li>\n<li>3E4<\/li>\n<li>1E5<\/li>\n<\/ul>\n<p>The model designation is related to the nominal flow impedance of the molbloc.<\/p>\n<p>Different flow ranges are achieved by changing the size of the annular gap and, for higher flows, by using larger molbloc bodies.<\/p>\n<p>This enables the appropriate flow element to be selected according to the required calibration range.<\/p>\n<h2>Nominal Flow Conditions<\/h2>\n<p>Fluke defines the nominal molbloc-L flow ranges using nitrogen under specified pressure conditions.<\/p>\n<p>The nominal impedance produces the nominal flow range when operating with:<\/p>\n<p><strong>Nitrogen \u2013 N\u2082<\/strong><\/p>\n<p>at approximately:<\/p>\n<p><strong>250 kPa absolute upstream pressure<\/strong><\/p>\n<p>and:<\/p>\n<p><strong>50 kPa differential pressure<\/strong><\/p>\n<p>across the molbloc.<\/p>\n<p>The actual flow range can differ significantly from the nominal value when another gas or another operating pressure configuration is used.<\/p>\n<p>This is because gas density and viscosity influence the relationship between differential pressure and mass flow.<\/p>\n<h2>Measurement Uncertainty Down to \u00b10.125%<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> provides excellent measurement performance.<\/p>\n<p>With Standard calibration and a compatible molbox terminal, Fluke specifies measurement uncertainty from 10% to 100% FS of:<\/p>\n<p><strong>\u00b10.2% of reading<\/strong>.<\/p>\n<p>Below 10% FS, the specification becomes:<\/p>\n<p><strong>\u00b10.02% FS<\/strong>.<\/p>\n<p>With Premium calibration, performance improves to:<\/p>\n<p><strong>\u00b10.125% of reading from 10% to 100% FS<\/strong><\/p>\n<p>and:<\/p>\n<p><strong>\u00b10.0125% FS below 10% FS<\/strong>.<\/p>\n<p>This measurement performance makes the molbloc-L suitable for demanding calibration and metrology applications.<\/p>\n<p>Premium calibration is not available for the 1E5 molbloc-L.<\/p>\n<h2>High Precision<\/h2>\n<p>For Standard and Premium molbloc-L configurations, Fluke specifies precision of:<\/p>\n<p><strong>\u00b10.07% of reading from 10% to 100% FS<\/strong><\/p>\n<p>and:<\/p>\n<p><strong>\u00b10.007% FS below 10% FS<\/strong>.<\/p>\n<p>Precision combines important short-term measurement characteristics including linearity, hysteresis and repeatability.<\/p>\n<p>The specified resolution is:<\/p>\n<p><strong>0.0015% FS<\/strong>.<\/p>\n<p>These characteristics allow small changes in gas flow to be detected and evaluated.<\/p>\n<h2>Excellent Linearity<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> provides specified linearity of:<\/p>\n<p><strong>\u00b10.05% of reading from 10% to 100% FS<\/strong>.<\/p>\n<p>Below 10% FS, linearity is specified as:<\/p>\n<p><strong>\u00b10.005% FS<\/strong>.<\/p>\n<p>This is particularly valuable when one molbloc-L is used across a broad part of its calibrated range.<\/p>\n<p>The excellent linearity contributes to the overall measurement performance of the molbloc\/molbox system.<\/p>\n<h2>Excellent Repeatability<\/h2>\n<p>Repeatability is specified at:<\/p>\n<p><strong>\u00b10.05% of reading from 10% to 100% FS<\/strong><\/p>\n<p>and:<\/p>\n<p><strong>\u00b10.005% FS below 10% FS<\/strong>.<\/p>\n<p>Good repeatability is essential for calibration work because repeated measurements at the same nominal flow should provide consistent reference values.<\/p>\n<p>Combined with the absence of moving measurement components, this contributes to the molbloc-L&#8217;s suitability as a flow transfer standard.<\/p>\n<h2>Long-Term Stability<\/h2>\n<p>With Standard calibration, predicted one-year stability is specified as:<\/p>\n<p><strong>\u00b10.09% of reading from 10% to 100% FS<\/strong><\/p>\n<p>and:<\/p>\n<p><strong>\u00b10.009% FS below 10% FS<\/strong>.<\/p>\n<p>With Premium calibration, predicted one-year stability improves to:<\/p>\n<p><strong>\u00b10.03% of reading<\/strong><\/p>\n<p>and:<\/p>\n<p><strong>\u00b10.003% FS below 10% FS<\/strong>.<\/p>\n<p>Long-term stability is particularly important for reference standards because changes between calibration intervals directly influence the uncertainty of measurements performed with the system.<\/p>\n<h2>No Moving Parts<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> contains no moving measurement parts.<\/p>\n<p>This provides several important advantages:<\/p>\n<ul>\n<li>No mechanical wear of a rotating measurement element<\/li>\n<li>High repeatability<\/li>\n<li>Excellent long-term stability<\/li>\n<li>Reduced maintenance<\/li>\n<li>Continuous measurement<\/li>\n<li>Predictable calibration behavior<\/li>\n<\/ul>\n<p>These characteristics make the molbloc-L particularly suitable for repeated use as a reference standard in professional calibration laboratories.<\/p>\n<h2>Integrated Contamination Filter<\/h2>\n<p>Clean gas is important for laminar flow measurement because contamination of the precision flow path could influence its flow characteristics.<\/p>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> therefore incorporates an integrated filter to help protect the flow element against contamination.<\/p>\n<p>Appropriate external gas preparation and filtration should nevertheless be used where necessary.<\/p>\n<p>Clean, dry calibration gas helps preserve the long-term metrological characteristics of the molbloc.<\/p>\n<h2>Integrated Gas Temperature Conditioning<\/h2>\n<p>The molbloc-L incorporates gas temperature conditioning and measurement.<\/p>\n<p>This is important because gas viscosity and density depend on temperature.<\/p>\n<p>The temperature information is measured by the molbox system and incorporated into the flow calculation.<\/p>\n<p>Together with pressure measurement and gas property data, this enables accurate determination of mass flow through the molbloc.<\/p>\n<h2>molbloc-L with Fluke Calibration molbox2<\/h2>\n<p>A modern molbloc-L calibration system can consist of:<\/p>\n<p><strong>Fluke Calibration molbloc-L + Fluke Calibration molbox2<\/strong><\/p>\n<p>The molbloc-L provides the characterized laminar flow element.<\/p>\n<p>The molbox2 measures the pressure and temperature conditions required to determine gas mass flow.<\/p>\n<p>The flow terminal combines these measurements with:<\/p>\n<ul>\n<li>Individual molbloc calibration data<\/li>\n<li>Gas characteristics<\/li>\n<li>Operating pressure<\/li>\n<li>Differential pressure<\/li>\n<li>Temperature<\/li>\n<\/ul>\n<p>to calculate the reference flow.<\/p>\n<p>The result is displayed continuously in real time.<\/p>\n<h2>Improved Performance with molbox2<\/h2>\n<p>The modern <strong>Fluke Calibration molbox2<\/strong> includes expanded molbloc modeling specifically designed to improve molbloc-L performance across different operating pressures.<\/p>\n<p>The molbox2 also uses updated gas property information based on:<\/p>\n<p><strong>NIST REFPROP10<\/strong>.<\/p>\n<p>Fluke Calibration has additionally continued to improve its molbloc calibration chain using fundamental mass- and time-based measurements with its dynamic gravimetric flow standard.<\/p>\n<p>These developments provide additional flexibility when using molbloc-L elements with different gases and operating pressures.<\/p>\n<h2>Different Operating Pressure Calibrations<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> can be calibrated for different operating pressure conditions.<\/p>\n<p>Available configurations include operating with atmospheric pressure downstream as well as defined low-pressure and high-pressure upstream conditions.<\/p>\n<p>For example, Fluke lists molbloc-L operating pressure calibration options including:<\/p>\n<p><strong>Low Pressure: approximately 250 to 325 kPa absolute upstream<\/strong><\/p>\n<p>and:<\/p>\n<p><strong>High Pressure: approximately 325 to 525 kPa absolute upstream<\/strong>.<\/p>\n<p>The correct configuration depends on the intended gas flow range and calibration setup.<\/p>\n<p>Selecting the appropriate operating pressure calibration improves the performance of the molbloc under the actual conditions of use.<\/p>\n<h2>Different Gas Calibrations<\/h2>\n<p>A standard molbloc-L is supplied with a low-pressure nitrogen calibration.<\/p>\n<p>Additional calibrations can be ordered for other pressure ranges or gases.<\/p>\n<p>This provides flexibility when the molbloc-L is used in applications involving gases other than nitrogen.<\/p>\n<p>With modern molbox2 modeling and NIST REFPROP10 gas properties, traceable specifications are also available for selected gases based on nitrogen calibration without requiring actual-gas calibration in every case.<\/p>\n<p>For the highest measurement performance, the selected calibration configuration should be matched to the actual gas and operating conditions.<\/p>\n<h2>Calibration of Mass Flow Controllers<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> is particularly well suited to calibration of thermal mass flow controllers.<\/p>\n<p>A typical setup consists of:<\/p>\n<p><strong>Gas Supply \u2192 Device Under Test \u2192 molbloc-L<\/strong><\/p>\n<p>or an alternative arrangement appropriate to the pressure requirements of the device under test.<\/p>\n<p>The molbox terminal determines the reference gas mass flow through the molbloc.<\/p>\n<p>This value can then be compared with:<\/p>\n<ul>\n<li>MFC setpoint<\/li>\n<li>MFC indication<\/li>\n<li>Analog output<\/li>\n<li>Digital output<\/li>\n<\/ul>\n<p>Multiple calibration points can be generated across the flow range to evaluate the performance of the mass flow controller.<\/p>\n<h2>Calibration of Mass Flow Meters<\/h2>\n<p>The molbloc-L can also be used to calibrate a broad range of 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>Variable-area flow meters<\/li>\n<li>Rotameters<\/li>\n<li>Gas flow sensors<\/li>\n<li>Process flow meters<\/li>\n<li>Low-flow meters<\/li>\n<li>Gas analyzers<\/li>\n<li>Air monitoring flow standards<\/li>\n<\/ul>\n<p>The continuous real-time measurement allows the operator to directly observe the response of the device under test.<\/p>\n<h2>Real-Time Flow Measurement<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> provides continuous real-time flow measurement.<\/p>\n<p>Unlike flow standards that require gas to be collected over a defined time interval before a result is available, the molbloc\/molbox system provides an immediate reference flow indication.<\/p>\n<p>This is particularly useful for:<\/p>\n<ul>\n<li>Adjusting mass flow controllers<\/li>\n<li>Calibrating analog flow meters<\/li>\n<li>Evaluating flow stability<\/li>\n<li>Performing multiple calibration points<\/li>\n<li>Automated calibration sequences<\/li>\n<\/ul>\n<p>Real-time measurement can significantly increase calibration productivity.<\/p>\n<h2>Fully Automated Calibration<\/h2>\n<p>The molbloc-L system can be fully automated.<\/p>\n<p>Combined with compatible Fluke Calibration hardware and software, complete gas flow calibration sequences can be performed automatically.<\/p>\n<p>Automation can include:<\/p>\n<ul>\n<li>Device-under-test control<\/li>\n<li>Flow setting<\/li>\n<li>Pressure measurement<\/li>\n<li>Temperature measurement<\/li>\n<li>Reference flow determination<\/li>\n<li>Stabilization<\/li>\n<li>Data acquisition<\/li>\n<li>Calibration point sequencing<\/li>\n<li>Result processing<\/li>\n<\/ul>\n<p>This makes the system suitable for laboratories with both low-volume manual calibration requirements and high-throughput automated calibration workloads.<\/p>\n<h2>COMPASS for Flow Software<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> can be integrated with:<\/p>\n<p><strong>COMPASS for Flow<\/strong><\/p>\n<p>calibration software.<\/p>\n<p>COMPASS for Flow supports automated flow calibration procedures using Fluke Calibration flow hardware.<\/p>\n<p>Depending on system configuration, the software can coordinate the reference standard, device under test and associated flow control hardware.<\/p>\n<p>This enables reproducible calibration sequences and efficient data collection.<\/p>\n<h2>NIST Traceability<\/h2>\n<p>Each standard molbloc-L is supplied with a calibration report documenting traceability to the:<\/p>\n<p><strong>United States National Institute of Standards and Technology \u2013 NIST<\/strong>.<\/p>\n<p>The report includes measured calibration data.<\/p>\n<p>This documented traceability is an important part of using the molbloc-L as a professional gas flow transfer standard.<\/p>\n<p>The individual calibration data characterize the specific molbloc rather than relying solely on nominal manufacturing dimensions.<\/p>\n<h2>Standard Scope of Delivery<\/h2>\n<p>According to Fluke Calibration, each molbloc-L is supplied with:<\/p>\n<ul>\n<li>Storage and shipping case<\/li>\n<li>Soft reusable VCR O-rings<\/li>\n<li>Mounting instructions<\/li>\n<li>Full-modification low-pressure nitrogen calibration<\/li>\n<li>Calibration report<\/li>\n<li>Measured calibration data<\/li>\n<li>Documented NIST traceability<\/li>\n<\/ul>\n<p>Alternative nitrogen calibrations or calibrations using other gases can be ordered separately.<\/p>\n<h2>molstic-L Mounting System<\/h2>\n<p>Fluke Calibration also offers the:<\/p>\n<p><strong>molstic-L<\/strong><\/p>\n<p>mounting system for molbloc-L elements.<\/p>\n<p>The molstic-L provides a practical mechanical and pneumatic platform for installing the molbloc within a gas flow calibration system.<\/p>\n<p>It helps address practical issues such as:<\/p>\n<ul>\n<li>Stable mounting<\/li>\n<li>Pneumatic connections<\/li>\n<li>Flow system configuration<\/li>\n<li>Changing molbloc elements<\/li>\n<li>Integration into calibration benches<\/li>\n<\/ul>\n<p>The combination of molbloc-L, molstic-L and molbox creates a modular flow calibration workstation.<\/p>\n<h2>Technical Highlights<\/h2>\n<table>\n<tbody>\n<tr>\n<th>Feature<\/th>\n<th>Fluke Calibration molbloc-L<\/th>\n<\/tr>\n<tr>\n<td>Device type<\/td>\n<td>Laminar flow element<\/td>\n<\/tr>\n<tr>\n<td>Measurement principle<\/td>\n<td>Laminar gas flow<\/td>\n<\/tr>\n<tr>\n<td>Family flow range<\/td>\n<td>Approx. 1 sccm to 100 slm<\/td>\n<\/tr>\n<tr>\n<td>Individual range<\/td>\n<td>Depends on molbloc size, gas and pressure<\/td>\n<\/tr>\n<tr>\n<td>Standard uncertainty<\/td>\n<td>\u00b10.2% of reading from 10\u2013100% FS<\/td>\n<\/tr>\n<tr>\n<td>Premium uncertainty<\/td>\n<td>\u00b10.125% of reading from 10\u2013100% FS<\/td>\n<\/tr>\n<tr>\n<td>Precision<\/td>\n<td>\u00b10.07% of reading from 10\u2013100% FS<\/td>\n<\/tr>\n<tr>\n<td>Linearity<\/td>\n<td>\u00b10.05% of reading from 10\u2013100% FS<\/td>\n<\/tr>\n<tr>\n<td>Repeatability<\/td>\n<td>\u00b10.05% of reading from 10\u2013100% FS<\/td>\n<\/tr>\n<tr>\n<td>Resolution<\/td>\n<td>0.0015% FS<\/td>\n<\/tr>\n<tr>\n<td>Premium 1-year stability<\/td>\n<td>\u00b10.03% of reading from 10\u2013100% FS<\/td>\n<\/tr>\n<tr>\n<td>Measurement update rate<\/td>\n<td>1 second<\/td>\n<\/tr>\n<tr>\n<td>Moving measurement parts<\/td>\n<td>None<\/td>\n<\/tr>\n<tr>\n<td>Contamination protection<\/td>\n<td>Integrated filter<\/td>\n<\/tr>\n<tr>\n<td>Temperature measurement<\/td>\n<td>Integrated<\/td>\n<\/tr>\n<tr>\n<td>Standard calibration gas<\/td>\n<td>Nitrogen<\/td>\n<\/tr>\n<tr>\n<td>Compatible terminal<\/td>\n<td>molbox2 \/ compatible molbox systems<\/td>\n<\/tr>\n<tr>\n<td>Automation<\/td>\n<td>COMPASS for Flow<\/td>\n<\/tr>\n<tr>\n<td>Traceability<\/td>\n<td>NIST documented<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>molbloc-L vs. molbloc-S<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> and molbloc-S are both precision gas mass flow elements within the Fluke Calibration molbloc\/molbox system, but they use fundamentally different measurement principles.<\/p>\n<p>The <strong>molbloc-L<\/strong> uses a:<\/p>\n<p><strong>laminar flow element<\/strong>.<\/p>\n<p>The <strong>molbloc-S<\/strong> uses a:<\/p>\n<p><strong>critical-flow sonic nozzle<\/strong>.<\/p>\n<p>The molbloc-L family is particularly suitable for low and medium flow rates, covering approximately:<\/p>\n<p><strong>1 sccm to 100 slm<\/strong>.<\/p>\n<p>The molbloc-S extends the molbloc concept into significantly higher gas flow ranges.<\/p>\n<p>Another important difference is the usable measurement range.<\/p>\n<p>The molbloc-L can operate from near zero to the full-scale flow of the selected element, depending on gas and operating pressure.<\/p>\n<p>The molbloc-S requires critical-flow conditions and is normally specified from approximately 10% to 100% FS.<\/p>\n<p>The two technologies therefore complement each other within a complete professional gas flow calibration laboratory.<\/p>\n<h2>molbloc-L vs. Conventional Flow Meter<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> should not be considered a conventional stand-alone flow meter.<\/p>\n<p>It is a characterized reference flow element intended to operate with a compatible molbox flow terminal.<\/p>\n<p>The molbloc provides the precision flow restriction and individual calibration characteristics.<\/p>\n<p>The molbox provides the required pressure and temperature measurements, gas property calculations and flow indication.<\/p>\n<p>Together they form the complete gas mass flow measurement system.<\/p>\n<p>This modular design enables one flow terminal to be used with several molbloc elements covering different flow ranges.<\/p>\n<h2>Applications of the Fluke Calibration molbloc-L<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> is suitable for:<\/p>\n<ul>\n<li>Gas mass flow calibration<\/li>\n<li>Low gas flow calibration<\/li>\n<li>Mass flow controller calibration<\/li>\n<li>Mass flow meter calibration<\/li>\n<li>Thermal flow meter calibration<\/li>\n<li>Rotameter calibration<\/li>\n<li>Variable-area flow meter calibration<\/li>\n<li>Gas flow sensor calibration<\/li>\n<li>Process flow meter calibration<\/li>\n<li>Air monitoring equipment<\/li>\n<li>Gas analyzer flow calibration<\/li>\n<li>Semiconductor applications<\/li>\n<li>Pharmaceutical applications<\/li>\n<li>Environmental monitoring<\/li>\n<li>Research laboratories<\/li>\n<li>Calibration laboratories<\/li>\n<li>Industrial metrology<\/li>\n<li>Gas flow metrology<\/li>\n<\/ul>\n<h2>Why Choose the Fluke Calibration molbloc-L?<\/h2>\n<p>The <strong>Fluke Calibration molbloc-L<\/strong> provides a precise, stable and highly flexible reference for low and medium gas flow calibration.<\/p>\n<p>Its laminar flow path is formed by the precisely controlled gap between a piston and cylindrical bore, providing a predictable relationship between gas flow and differential pressure.<\/p>\n<p>A family flow range from approximately <strong>1 sccm to 100 slm<\/strong> enables different molbloc-L elements to cover several decades of gas flow.<\/p>\n<p>With Premium calibration, measurement uncertainty can reach <strong>\u00b10.125% of reading from 10% to 100% FS<\/strong>, while precision is specified at <strong>\u00b10.07% of reading<\/strong>.<\/p>\n<p>The absence of moving measurement parts supports excellent repeatability and long-term stability, while the integrated filter protects the precision flow path against contamination.<\/p>\n<p>Integral gas temperature conditioning and measurement provide the temperature information required for accurate mass flow calculation.<\/p>\n<p>Combined with the modern <strong>Fluke Calibration molbox2<\/strong>, expanded molbloc modeling and NIST REFPROP10 gas property data further improve flexibility across different operating pressures and gases.<\/p>\n<p>The result is a modular gas flow transfer standard that can be used manually or integrated into a fully automated calibration system using COMPASS for Flow.<\/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-L<\/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-L-1E5-molbloc-100-slm-Mass-Flow-Element.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-L<\/strong> is a precise laminar flow element for professional gas mass flow measurement and calibration from approximately <strong>1 sccm to 100 slm<\/strong>. With no moving parts, integrated temperature measurement and measurement uncertainty down to <strong>\u00b10.125% of reading<\/strong> with Premium calibration, it provides an accurate and stable reference for flow meter and mass flow controller calibration when combined with a compatible molbox flow terminal.<\/p>\n","protected":false},"featured_media":3160,"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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