Fluke Calibration molstic-S is a modular flow mounting system designed specifically for Fluke Calibration molbloc-S sonic nozzle mass flow elements. It provides an engineered solution for mounting molbloc-S elements, connecting the gas supply, regulating operating pressure and integrating the device under test into a professional gas flow calibration system.
Rather than being a flow measurement standard itself, the molstic-S provides the mechanical and pneumatic infrastructure required to operate molbloc-S flow elements correctly and efficiently. Combined with a molbloc-S and a compatible molbox flow terminal, the system creates a flexible platform for calibrating mass flow meters, mass flow controllers and other gas flow measurement devices.
The modular design allows the device under test to be positioned either upstream or downstream of the molbloc-S, depending on the operating principle and pressure requirements of the instrument being calibrated.
Fluke Calibration offers the molstic-S in both 1/4 inch and 1/2 inch system plumbing sizes as well as Single and Dual configurations. The Dual version allows two molbloc-S elements to remain installed simultaneously, enabling two different flow ranges to be used without changing the flow hardware between tests.
Integrated shut-off and metering valves simplify leak testing and flow adjustment, while optional pressure regulators, back-pressure regulators, high-resolution metering valves and an adjustable DUT stand allow the system to be configured for different calibration applications.
At europascal, the Fluke Calibration molstic-S complements a comprehensive range of professional flow calibration equipment including molbox flow terminals and molbloc flow elements. For professional calibration and metrological traceability, visit the europascal Calibration Service.
Your Benefits at a Glance
The Fluke Calibration molstic-S provides a professional and modular platform for building molbloc-S gas flow calibration systems.
Key advantages include:
- Designed specifically for molbloc-S sonic nozzle flow elements
- Professional mechanical mounting platform
- Integrated pneumatic connections
- Single and Dual configurations available
- 1/4 inch and 1/2 inch system plumbing sizes
- Allows upstream or downstream DUT positioning
- Integrated flow shut-off and metering valves
- Supports system leak testing
- Optional pressure reducing regulator
- Optional back-pressure regulator
- Optional high-resolution metering valves
- Filter included with the 1/4 inch version
- Protects smaller molbloc-S elements against contamination
- Optional adjustable DUT stand
- Dual configurations support two molbloc-S ranges
- Two molbloc-S outlets can be connected in parallel
- Designed for professional calibration laboratories
- Optimized for the molbloc/molbox calibration system
Designed for molbloc-S Sonic Nozzle Flow Elements
The Fluke Calibration molstic-S has been developed specifically for the molbloc-S family of sonic nozzle mass flow elements.
A complete calibration configuration can consist of:
Gas Supply + molstic-S + molbloc-S + molbox Flow Terminal + Device Under Test
The individual components perform different functions.
The molbloc-S is the characterized sonic nozzle flow element.
The molbox measures the required pressure and temperature parameters and calculates the reference mass flow.
The molstic-S provides the mechanical mounting, pneumatic connections and flow system components required to integrate the molbloc-S and the device under test.
This clear separation makes the molbloc/molbox platform highly modular.
Single and Dual Configurations
The Fluke Calibration molstic-S is available in Single and Dual configurations.
The:
molstic-S Single
accommodates one molbloc-S flow element.
This configuration is suitable when one flow range is required or when molbloc elements are changed manually for different calibration tasks.
The:
molstic-S Dual
allows two molbloc-S flow elements to be mounted simultaneously.
This provides an important practical advantage for laboratories working across multiple flow ranges.
Two molbloc-S elements with different nominal flow ranges can remain installed on the platform, allowing the operator to switch between ranges without physically replacing the reference flow element.
Dual molbloc-S Operation
The Dual molstic-S can accommodate two molbloc-S elements at the same time.
This allows:
two different flow ranges
to be available within the same calibration setup.
In suitable configurations, the outlets of the two molbloc-S elements can also be connected in parallel using a downstream tee assembly.
This enables additional flow capacity when used with an appropriate two-channel molbox system.
The Dual configuration can therefore improve both range coverage and laboratory productivity.
1/4 Inch molstic-S
The 1/4 inch molstic-S is intended for the smaller molbloc-S flow elements.
Fluke specifies it for:
molbloc-S 1E2-S and lower.
The 1/4 inch system is therefore particularly suitable for lower and medium flow applications.
A filter is integrated into the 1/4 inch molstic-S to help protect the smaller molbloc-S elements against contamination.
This is particularly important because contamination of a precision sonic nozzle can affect its metrological characteristics.
1/2 Inch molstic-S
The 1/2 inch molstic-S is intended for higher-flow molbloc-S elements.
Fluke specifies this version for:
molbloc-S 2E2-S through 2E3-S.
The larger plumbing diameter reduces unwanted pressure losses at higher gas flow rates.
Both Single and Dual versions are available with 1/2 inch plumbing.
The appropriate molstic-S configuration should therefore be selected according to the molbloc-S elements and flow ranges used in the calibration system.
Integrated Shut-Off and Metering Valves
All Fluke Calibration molstic-S platforms include integrated flow shut-off and metering valves.
These valves provide important practical functions during calibration.
They can be used for:
- Isolating sections of the flow system
- Performing system leak tests
- Starting and stopping gas flow
- Adjusting flow where required by the DUT configuration
- Preparing the system for component changes
The integrated valve arrangement reduces the need to assemble a calibration system from individual third-party pneumatic components.
High-Resolution Metering Valve Option
For applications requiring particularly fine flow adjustment, Fluke offers optional high-resolution metering valve kits for the:
1/4 inch molstic-S.
These valves provide finer flow control than the standard metering arrangement.
This can be useful when calibrating instruments at specific flow points or when the device under test requires precise manual flow adjustment.
Upstream and Downstream DUT Positioning
One of the most important advantages of the Fluke Calibration molstic-S is its modular layout.
The device under test can be installed:
upstream of the molbloc-S
or:
downstream of the molbloc-S.
The correct arrangement depends on the type of device being calibrated and its operating pressure requirements.
This flexibility is particularly useful because sonic nozzle calibration systems have different pneumatic requirements depending on whether the device under test controls the flow or simply measures it.
DUTs with Flow Control
The molbloc-S operates in the critical-flow regime.
For a device under test that has its own flow control capability, Fluke specifies that the DUT must be installed:
upstream of the molbloc-S.
Examples can include certain mass flow controllers and other active flow-control devices.
In this arrangement, the DUT controls the gas flow while the molbloc-S provides the reference flow measurement.
The molstic-S modular plumbing concept supports this upstream configuration.
DUTs Operating at Atmospheric Pressure
Devices intended to be calibrated at atmospheric pressure are generally installed:
downstream of the molbloc-S.
In this arrangement, the gas first passes through the molbloc-S sonic nozzle and then through the device under test.
The molstic-S can be equipped with the appropriate pressure regulation components to support this configuration.
The ability to configure the DUT either upstream or downstream significantly increases the versatility of the calibration platform.
Pressure Regulation
Correct inlet pressure regulation is extremely important in a molbloc/molbox calibration system.
The pressure transducers inside the molbox must be protected against excessive pressure.
For this reason, Fluke offers pressure regulation options for the molstic-S.
A pressure reducing regulator can be installed when calibrating devices that operate at atmospheric pressure.
This provides controlled supply pressure to the molbloc-S and helps maintain the required operating conditions.
Supply Only molstic-S
Fluke also offers a:
molstic-S Supply Only
configuration.
This version acts as an upstream gas supply regulation platform.
It is available in:
1/4 inch
and:
1/2 inch
versions.
Fluke recommends the Supply Only configuration upstream of devices that have their own flow control capability.
This provides a controlled gas supply while protecting the pressure measurement components of the calibration system.
Optional Back-Pressure Regulator
An optional back-pressure regulator can be installed on the Fluke Calibration molstic-S.
The back-pressure regulator can be used to control the downstream pressure of a device under test positioned upstream of the molbloc-S.
This is particularly useful when the DUT requires a defined outlet pressure for correct operation or calibration.
The modular regulator options therefore allow the molstic-S to be adapted to different pneumatic calibration requirements.
Protection Against Contamination
Clean gas is essential for maintaining the metrological performance of precision flow standards.
The 1/4 inch molstic-S includes a filter specifically designed to protect the smaller molbloc-S elements from contamination.
Particles entering the sonic nozzle could alter its effective geometry and therefore influence its flow characteristics.
The integrated filter helps protect the reference element and supports long-term stability.
Appropriate clean and dry calibration gas should nevertheless always be used.
Optional Adjustable DUT Stand
Large devices under test may not fit directly on the standard molstic-S platform.
For these applications, Fluke offers an optional:
Adjustable DUT Stand
with part number:
401934.
The stand provides mechanical support for larger DUTs while maintaining an appropriate connection to the molstic-S flow system.
This is particularly useful for larger mass flow meters and other instruments with substantial housings or unusual connection positions.
Compact Modular Construction
The molstic-S integrates high-quality pneumatic components into a compact mounting platform.
A typical Single molstic-S has an overall platform length of approximately:
590 mm / 23 inches.
The basic platform height is approximately:
103.5 mm / 4 inches.
Its modular design helps create a cleaner and more reproducible calibration setup than assembling the system from separate tubing, valves, filters and mounting hardware.
This is particularly valuable in professional calibration laboratories where repeatable system configuration is important.
molstic-S with molbloc-S
The Fluke Calibration molstic-S and molbloc-S perform complementary functions.
The:
molbloc-S
is the actual precision sonic nozzle mass flow element.
The:
molstic-S
is the mounting and pneumatic system.
The molstic-S does not independently measure gas flow.
Instead, it ensures that the molbloc-S can be installed and operated in a controlled and practical calibration configuration.
The complete system then uses a compatible molbox terminal to determine and display the reference gas mass flow.
molstic-S with molbox
A complete professional flow calibration system can combine:
molstic-S + molbloc-S + molbox
The molstic-S handles:
- Mechanical mounting
- Gas connections
- Isolation
- Flow adjustment
- Pressure regulation options
- DUT integration
The molbloc-S provides:
- Precision sonic nozzle
- Characterized flow element
- Reference flow characteristics
The molbox provides:
- Pressure measurement
- Temperature measurement
- Flow calculation
- Reference flow indication
- System communication
Together, these components form a modular gas flow calibration platform.
Critical Flow Considerations
The molbloc-S mounted on the molstic-S operates according to the critical-flow or choked-flow principle.
When the required pressure ratio is reached, the gas reaches sonic velocity at the nozzle throat.
Under these conditions, mass flow is primarily determined by:
- Upstream absolute pressure
- Gas temperature
- Sonic nozzle geometry
- Gas properties
The downstream pressure must remain sufficiently low relative to upstream pressure to maintain critical-flow conditions.
The molstic-S helps create the required pneumatic configuration while providing the flexibility needed for different DUT arrangements.
Calibration of Mass Flow Controllers
The Fluke Calibration molstic-S is particularly useful for building calibration systems for mass flow controllers.
For an MFC that controls its own flow, the typical arrangement places the MFC:
upstream of the molbloc-S.
A controlled gas supply feeds the MFC.
The molbloc-S then provides the reference flow downstream of the MFC.
Depending on the application, the molstic-S Supply Only platform and optional back-pressure regulation can be used to establish the required pressure conditions.
Calibration of Flow Meters
For passive flow measurement devices, the device under test can often be positioned downstream of the molbloc-S.
Typical DUTs can include:
- Mass flow meters
- Thermal flow meters
- Variable-area flow meters
- Rotameters
- Process gas flow meters
- Gas flow sensors
The exact configuration depends on the pressure requirements and pressure drop of the DUT.
The modular molstic-S concept makes it easier to adapt the system to these different applications.
Single vs. Dual molstic-S
The correct Fluke Calibration molstic-S configuration depends primarily on the required number of flow ranges.
A Single molstic-S is suitable when:
- One molbloc-S is normally used
- Flow ranges are changed infrequently
- A compact configuration is preferred
A Dual molstic-S is particularly useful when:
- Two flow ranges are frequently required
- Calibration throughput is important
- Hardware changes should be minimized
- Two molbloc-S elements need to remain permanently installed
The Dual configuration can therefore significantly improve workflow efficiency in a calibration laboratory.
Technical Highlights
| Feature | Fluke Calibration molstic-S |
|---|---|
| Device type | Mounting system for molbloc-S |
| Application | Gas flow calibration |
| Reference element | molbloc-S sonic nozzle |
| Configurations | Single / Dual |
| Plumbing sizes | 1/4 inch / 1/2 inch |
| 1/4 inch compatibility | molbloc-S 1E2-S and lower |
| 1/2 inch compatibility | molbloc-S 2E2-S through 2E3-S |
| Integrated valves | Shut-off / metering |
| Leak testing | Supported |
| Integrated filter | 1/4 inch version |
| Pressure regulator | Optional |
| Back-pressure regulator | Optional |
| High-resolution metering valve | Optional for 1/4 inch |
| DUT position | Upstream or downstream |
| Adjustable DUT stand | Optional |
| Single platform length | Approx. 590 mm |
| Automation | Suitable for automated molbloc/molbox systems |
Available molstic-S Configurations
Fluke Calibration offers several molstic-S configurations to match different flow calibration requirements.
These include:
molstic-S Single 1/4 inch
For one molbloc-S, 1E2-S and lower.
molstic-S Single 1/2 inch
For one molbloc-S, 2E2-S through 2E3-S.
molstic-S Dual 1/4 inch
For two molbloc-S elements, 1E2-S and lower.
molstic-S Dual 1/2 inch
For two molbloc-S elements, 2E2-S through 2E3-S.
molstic-S Supply Only 1/4 inch
Upstream regulation platform with 1/4 inch plumbing.
molstic-S Supply Only 1/2 inch
Upstream regulation platform with 1/2 inch plumbing.
Optional pressure reducing regulators and back-pressure regulators are available for both plumbing sizes.
molstic-S vs. molbloc-S
The distinction between the two products is important.
Fluke Calibration molstic-S = Mounting and pneumatic system
Fluke Calibration molbloc-S = Sonic nozzle mass flow element
The molstic-S itself is therefore not a flow reference or flow meter.
Its purpose is to provide a professionally engineered platform on which the molbloc-S and the device under test can be operated under suitable pneumatic conditions.
molstic-S vs. molstic-L
The molstic-S is designed for:
molbloc-S sonic nozzle flow elements.
The molstic-L is designed for:
molbloc-L laminar flow elements.
The different mounting systems reflect the different operating principles and pneumatic requirements of the two molbloc technologies.
For a calibration laboratory using both molbloc-L and molbloc-S standards, the corresponding molstic platforms provide a structured and modular approach to system construction.
Typical Applications
The Fluke Calibration molstic-S is suitable for building systems for:
- Gas mass flow calibration
- Mass flow controller calibration
- Mass flow meter calibration
- Sonic nozzle flow calibration
- Rotameter calibration
- Variable-area flow meter calibration
- Thermal mass flow meter calibration
- Process flow meter calibration
- Gas flow sensor calibration
- Calibration laboratory applications
- Industrial flow metrology
- Research and development
- Automated gas flow calibration
Why Choose the Fluke Calibration molstic-S?
The Fluke Calibration molstic-S provides a professionally engineered mechanical and pneumatic platform for molbloc-S sonic nozzle mass flow elements.
Rather than assembling a flow calibration system from individual valves, fittings, filters, tubing and mounting components, the molstic-S integrates the key elements into a compact modular platform designed specifically for the molbloc/molbox system.
Single and Dual configurations allow one or two molbloc-S elements to be permanently installed.
The 1/4 inch version supports molbloc-S elements 1E2-S and lower, while the 1/2 inch version supports elements from 2E2-S through 2E3-S.
Integrated shut-off and metering valves simplify system isolation, leak testing and flow adjustment. Optional pressure reducing regulators, back-pressure regulators and high-resolution metering valves allow the system to be optimized for different DUT configurations.
The modular design also enables the device under test to be positioned upstream or downstream of the molbloc-S depending on its operating principle and pressure requirements.
Combined with a Fluke Calibration molbloc-S and compatible molbox flow terminal, the molstic-S forms an important part of a flexible and professional gas mass flow calibration system.
At europascal, we provide Fluke Calibration flow, pressure, temperature and electrical calibration technology for professional laboratory and industrial applications.
For professional calibration and metrological traceability, visit the europascal Calibration Service.
Further products from Fluke Calibration are available from europascal.
Manufacturer information about the Fluke Calibration molstic-S is available on the official Fluke Calibration website.
