Laminar flow elements for flow from 1 sccm to 100 slm

molbloc-Ls are laminar flow elements for use with molbox mass flow terminals. The molbloc flow path is the longitudinal, annular gap between a piston and a close fitting cylindrical bore in the molbloc body. Different molbloc ranges are obtained by varying the size of the gap. For high flow ranges (size 1E4 and above), a larger molbloc body with a larger cylindrical bore is used.

Features at a glance

Learn the difference between mass flow and volume flow in "Mass flow versus volume flow in gas flow calibration."

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  • Useable with existing molbox1+ and molbox RFM mass flow terminals and COMPASS software
  • Integrated filter to protect against contamination
  • Integral gas temperature conditioning and measurement
  • Continuous, real-time reading
  • Can be fully automated
  • No moving parts

molbloc-L Ranges
molblocs sizes are designated by a number relative to their nominal flow impedance. The nominal impedance results in nominal flow ranges when flowing nitrogen gas with 250 kPa absolute (36 psia) upstream pressure and 50 kPa (7.5 psid) differential pressure across the molbloc. In practice, the molbloc flow range may be quite different from the nominal flow range. The difference comes from differences in density and viscosity between gases and from different molbloc operating pressure calibration options.

Specifications - Standard molbloc-L Calibrations - Used with molbox1+ terminal

Measurement Update Rate 1 second
Range 0 to molbloc full scale depending on gas and molbloc pressure
dependent calibration type (see Section 1.2.5.1.3)
Resolution 0.0015 % FS
Linearity ± 0.05 % of reading from 10 to 100 % FS,
± 0.005 % FS under 10 % FS
Repeatability ± 0.05 % of reading from 10 to 100 % FS,
± 0.005 % FS under 10 % FS
Precision1 ± 0.07 % of reading from 10 to 100 % FS,
± 0.007 % FS under 10 % FS
Stability2
(1 year)
± 0.09 % of reading from 10 to 100 % FS,
± 0.009 % FS under 10 % FS
Measurement Uncertainty3 ± 0.2 % of reading from 10 to 100 % FS,
± 0.02 % FS under 10 % FS
(N2 and any molbox1+ supported gas for which the molbloc in use is calibrated) 1E5 molbloc
± 0.5% of reading from 25 to 100 % FS,
± 0.125 % FS under 25 % FS
1 Precision: Combined linearity, hysteresis, repeatability.
2 Stability: Maximum change in zero and span over specified time period for typical molbox1+ and molbloc used under typical conditions. As stability can only be predicted, stability for a specific molbloc and molbox1+ should be established from experience.
3 Measurement uncertainty (accuracy): Maximum deviation of the molbox1+ flow indication from the true value of the flow through the molbloc including precision, stability and Fluke calibration standard measurement uncertainty.

Specifications - Premium molbloc-L Calibrations - Used with molbox1+ terminal

Measurement Update Rate 1 second
Range 0 to molbloc full scale depending on gas and molbloc pressure dependent calibration type (see Section 1.2.5.1.2)
Resolution 0.0015 % FS
Linearity ± 0.05 % of reading from 10 to 100 % FS,
± 0.005 % FS under 10 % FS
Repeatability ± 0.05 % of reading from 10 to 100 % FS,
± 0.005 % FS under 10 % FS
Precision1 ± 0.07 % of reading from 10 to 100 % FS,
± 0.007 % FS under 10 % FS
Stability2
(1 year)
± 0.03 % of reading from 10 to 100 % FS,
± 0.003 % FS under 10 % FS
Measurement Uncertainty3 ± 0.125 % of reading from 10 to 100 % FS,
± 0.0125 % FS under 10 % FS
(N2 and any molbox1+ supported gas for which the molbloc in use is calibrated) 1E5 molbloc-L Premium calibration not available
1 Precision: Combined linearity, hysteresis, repeatability.
2 Stability: Maximum change in zero and span over specified time period for typical molbox1+ and molbloc used under typical conditions. As stability can only be predicted, stability for a specific molbloc and molbox1+ should be established from experience.
3 Measurement uncertainty (accuracy): Maximum deviation of the molbox1+ flow indication from the true value of the flow through the molbloc including precision, stability and Fluke calibration standard measurement uncertainty.

Specifications - Standard molbloc-L Calibrations - Used with molbox RFM terminal

  molbloc-L (ranges 1E1-L thru 3E4-L)
Measurement update rate 1 second
Range 0 to molbloc full scale depending on gas and molbloc pressure dependent calibration type (see molbloc-L range sheet tables)
Resolution 0.01 % FS
Linearity ± 0.23 % of reading from 10 % to 100 % FS, ± 0.023 % FS under 10 % FS
Repeatability ± 0.1% of reading from 10 % to 100 % FS, ± 0.01% FS under 10 % FS
Precision1 ± 0.25 % of reading from 10 % to 100 % FS, ± 0.025 % FS under 10 % FS
Predicted stability2
(one year)
± 0.15 % of reading from 10 % to 100 % FS, ± 0.015 % FS under 10 % FS
Measurement uncertainty3 ± 0.5 % of reading from 10 % to 100 % FS, ± 0.05 % FS under 10 % FS

molbox RFM with Microrange option

  molbloc-L (ranges 1E1-L thru 3E4-L) molbloc-L (ranges 1E5 only)
Measurement update rate 1 second 1 second
Range 0 to molbloc full scale depending on gas and molbloc pressure dependent calibration type (see molbloc-L tables) 0 to molbloc full scale depending on gas and molbloc pressure dependent calibration type (see molbloc-L tables)
Resolution 0.01 % FS, 0.001 % FS under  0.001 % FS under 10% FS 0.01 % FS
Linearity ± 0.23 % of reading from 1 % to 100 % FS,
± 0.0023 % FS under 1 % FS
± 0.25 % of reading from 5 % to 100 % FS, ± 0.0125 % FS under 5 % FS
Repeatability ± 0.1 % of reading from 1 % to 100 % FS, ± 0.001 % FS under 1 % FS ± 0.2 % of reading from 5 % to 100 % FS, ± 0.01 % FS under 5% FS
Precision1 ± 0.25 % of reading from 1 % to 100 % FS, ± 0.0025 % FS under 1% FS ± 0.32 % of reading from 5 % to 100 % FS, ± 0.016 % FS under 5 % FS
Predicted stability2
(one year)
± 0.15 % of reading from 1 % to 100 % FS, ± 0.0015 % FS under 1 % FS ± 0.2 % of reading from 5 % to 100 % FS, ± 0.01 % FS under 5 % FS
Measurement uncertainty3 ± 0.5 % of reading from 1 % to 100 % FS, ± 0.005 % FS under 1 % FS ± 0.5 % of reading from 5 % to 100 % FS, ± 0.025 % FS under 5 % FS
Model Name Description
1E1 VCR-V-Q

molbloc Mass Flow Element
Each molbloc is delivered complete with:

  • Storage and shipping case
  • Soft, reusable VCR O-rings and mounting instructions
  • Full mod, low pressure Nitrogen (N2) calibration.
    A different N2 calibration and/or calibration with non-N2 gases must be ordered as separate line item.
  • Calibration report documenting traceability to the United States National Institute of Standards and Technology (NIST) and reporting measured calibration data
5E1 VCR-V-Q

molbloc Mass Flow Element
Each molbloc is delivered complete with:

  • Storage and shipping case
  • Soft, reusable VCR O-rings and mounting instructions
  • Full mod, low pressure Nitrogen (N2) calibration.
    A different N2 calibration and/or calibration with non-N2 gases must be ordered as separate line item.
  • Calibration report documenting traceability to the United States National Institute of Standards and Technology (NIST) and reporting measured calibration data
1E2 VCR-V-Q

molbloc Mass Flow Element
Each molbloc is delivered complete with:

  • Storage and shipping case
  • Soft, reusable VCR O-rings and mounting instructions
  • Full mod, low pressure Nitrogen (N2) calibration.
    A different N2 calibration and/or calibration with non-N2 gases must be ordered as separate line item.
  • Calibration report documenting traceability to the United States National Institute of Standards and Technology (NIST) and reporting measured calibration data
2E2 VCR-V-Q

molbloc Mass Flow Element
Each molbloc is delivered complete with:

  • Storage and shipping case
  • Soft, reusable VCR O-rings and mounting instructions
  • Full mod, low pressure Nitrogen (N2) calibration.
    A different N2 calibration and/or calibration with non-N2 gases must be ordered as separate line item.
  • Calibration report documenting traceability to the United States National Institute of Standards and Technology (NIST) and reporting measured calibration data
5E2 VCR-V-Q

molbloc Mass Flow Element
Each molbloc is delivered complete with:

  • Storage and shipping case
  • Soft, reusable VCR O-rings and mounting instructions
  • Full mod, low pressure Nitrogen (N2) calibration.
    A different N2 calibration and/or calibration with non-N2 gases must be ordered as separate line item.
  • Calibration report documenting traceability to the United States National Institute of Standards and Technology (NIST) and reporting measured calibration data
1E3 VCR-V-Q

molbloc Mass Flow Element
Each molbloc is delivered complete with:

  • Storage and shipping case
  • Soft, reusable VCR O-rings and mounting instructions
  • Full mod, low pressure Nitrogen (N2) calibration.
    A different N2 calibration and/or calibration with non-N2 gases must be ordered as separate line item.
  • Calibration report documenting traceability to the United States National Institute of Standards and Technology (NIST) and reporting measured calibration data
5E3 VCR-V-Q

molbloc Mass Flow Element
Each molbloc is delivered complete with:

  • Storage and shipping case
  • Soft, reusable VCR O-rings and mounting instructions
  • Full mod, low pressure Nitrogen (N2) calibration.
    A different N2 calibration and/or calibration with non-N2 gases must be ordered as separate line item.
  • Calibration report documenting traceability to the United States National Institute of Standards and Technology (NIST) and reporting measured calibration data
1E4 VCR-V-Q

molbloc Mass Flow Element

Each molbloc is delivered complete with:

  • Storage and shipping case
  • Soft, reusable VCR O-rings and mounting instructions
  • Full mod, low pressure Nitrogen (N2) calibration.
    A different N2 calibration and/or calibration with non-N2 gases must be ordered as separate line item.
  • Calibration report documenting traceability to the United States National Institute of Standards and Technology (NIST) and reporting measured calibration data
3E4 VCR-V-Q

molbloc Mass Flow Element
Each molbloc is delivered complete with:

  • Storage and shipping case
  • Soft, reusable VCR O-rings and mounting instructions
  • Full mod, low pressure Nitrogen (N2) calibration.
    A different N2 calibration and/or calibration with non-N2 gases must be ordered as separate line item.
  • Calibration report documenting traceability to the United States National Institute of Standards and Technology (NIST) and reporting measured calibration data
1E5 VCR-V-Q

molbloc Mass Flow Element
Each molbloc is delivered complete with:

  • Storage and shipping case
  • Soft, reusable VCR O-rings and mounting instructions
  • Full mod, low pressure Nitrogen (N2) calibration.
    A different N2 calibration and/or calibration with non-N2 gases must be ordered as separate line item.
  • Calibration report documenting traceability to the United States National Institute of Standards and Technology (NIST) and reporting measured calibration data
molbloc-S Calibration Options

Low Pressure 20 to 200 kPa (3 to 30 psia)
upstream of the molbloc (specify premium or standard)

Standard Pressure 50 to 600 kPa (7 to 87 psia)
upstream of the molbloc (specify premium or standard)

High Pressure 200 to 2000 kPa (30 to 300 psia)
upstream of the molbloc (specify premium or standard)

Accessories common to all models:

Accessory Description
molbloc-L Downstream

Operating Pressure (absolute):
Atmospheric pressure downstream of the molbloc
Specify Premium or Standard

molbloc-L High Pressure

Operating Pressure (absolute):
325 to 525 kPa (48 to 76 psia) upstream of the molbloc

molbloc-L Low Pressure

Operating Pressure (absolute):
250 to 325 kPa (36 to 48 psia) upstream of the molbloc
Specify Premium or Standard

Priority Gold Instrument CarePlan

Fluke Calibration Priority Gold Instrument CarePlans are available for most calibration products. Please contact your local Fluke Calibration sales representative for details or to request a quote. You may also call the Customer Care Center at 877-355-3225 or send email to careplans@flukecal.com.