molbox1+ Flow Terminal

Features at a glance

± 0.125 % of reading uncertainty on mass flow measurements with molbloc-L and molbloc-S elements with premium calibrations

• molbox1+S configuration gives extra rangeability with molbloc-S elements without requiring vacuum pumps
• Now use any molbloc element for both high and low pressure applications in the same gas
• Even more robust internal pneumatic design
• Full suite of software automation products and hardware accessories to create a complete gas flow calibration system—including new COMPASS® for Flow calibration assistance software

Unparalleled uncertainty specifications

molbox1+ innovations enable the molbloc/ molbox1+ system to achieve the lowest gas flow measurement uncertainties in the industry. The lower uncertainty is made possible by several key improvements, including:

• Use of Fluke Calibration's exclusive quartz reference pressure transducer (Q-RPT) technology to precisely measure both absolute and differential pressure. molbox1+ Q-RPTs are specially characterized sensors benefitting from the same technology used in Fluke Calibration’s pressure transfer standards.
• Premium molbloc calibrations linearize molbloc flow output to better capitalize on existing precision and repeatability.
• Expanded molbloc modelization enables improved performance of molbloc-L laminar flow elements across their range of operating pressures.
• Reduced uncertainty on gas properties utilizing data from NIST Reference Fluid Thermodynamic and Transport Properties Database (REFPROP).
• Continued improvements in Fluke Calibration’s molbloc calibration chain, based on fundamental massand time-based mass flow measurements using Fluke Calibration’s own dynamic Gravimetric Flow Standard.

Two levels of molbloc flow element calibration are now available to let you balance uncertainty and cost:

• Premium: ± 0.125 % of reading flow measurement uncertainty (with molbox1+)
• Standard: ± 0.2 % of reading flow measurement uncertainty (with molbox1 or molbox1+)

New molblocs are eligible for either calibration type. Existing molblocs are compatible with molbox1+ at ± 0.2 % of reading uncertainty with no changes required. See below for details on upgrade service to existing molblocs to allow premium calibration and measurement specifications.

The molbloc/molbox system has stood the test of time for flow meter calibration since the early 1990’s, used in many demanding calibration laboratories, intercomparisons and government organizations worldwide. Fluke Calibration’s uncertainty specifications are conservative and backed by a thorough uncertainty analysis and metrology support. Fluke Calibration’s innovation and design is continually aimed at making sure our products deliver specifications that can be realized by the user, not under best case conditions but in your real-world application.

molbox1+S sonic nozzle calibration device expands rangeability—without vacuum pumps molbox1+S is a special configuration of molbox 1+ that enables you to cover a wide range (10:1 range turndown) with molbloc-S sonic nozzle flow elements, without requiring costly vacuum pumps. molbox1+S sonic nozzle calibration device is available with upstream Q-RPT pressure range up to 2 MPa (300 psia) to allow molbloc-S elements to be conveniently used over a wide flow range upstream of flow meters being tested at atmospheric pressure, a common application. This extra rangeability makes it simple to configure a calibration system using fewer molbloc elements and minimal accessories. It also greatly extends the range of your existing molbloc-S elements when a high pressure molbloc calibration is added.

molbloc-S range example with device under test at atmospheric pressure

*Minimum usable flow of molbloc-S elements with SP calibrations are limited by back pressure requirements for sonic flow when used upstream of a device at atmospheric pressure. Flow values are in standard liters per minute referenced to 0 °C.

molbox1+S is designed for use with molbloc-S sonic nozzle calibration devices and therefore is configured for absolute pressure measurement only, reducing its cost. It also reduces flow system complexity and overall cost, as well as ongoing recalibration costs.

Use the same molbloc in multiple applications

Multiple molbloc calibrations are now supported for each gas. This means that you can now have a molbloc calibrated separately for use both at high pressure (upstream of the device under test) and low pressure (downstream of the device under test) to support different applications instead of requiring two molblocs or manually loading separate molbloc calibration files. All calibrations are stored on the molbloc EEPROM and the user simply selects the calibration type from the molbox1+ front panel or via molbox1+ remote interface.

COMPASS® for molbox and new COMPASS® for Flow software add automation and more

COMPASS calibration assistance software takes molbloc/molbox to the next step in automating calibrations. COMPASS and a personal computer work with molbloc/molbox to create a modern, full function, turnkey system for calibrating and testing flow devices.

COMPASS sets up device under test (DUT) records (also known as unit under test), defines and associates test procedures with DUTs, runs tests, acquires reference and test data, produces standard and custom calibration reports. Mass flow device gas correction factors and gas density corrections for volumetric devices like rotameters are easily supported, with options to dynamically calculate the corrected flow using automatic input of pressure and temperature measurements. All reference, DUT and test data are collected and stored in standard delimited files that can be easily downloaded to other applications.

A new version of the software, COMPASS for Flow, brings features to flow calibration that were previously only available in Fluke Calibration’s COMPASS for Pressure software. These include: 

• Ability to export data to Fluke MET/TRACK® software.
• Enhanced support for devices under test requiring custom calculations on output indications, special communications support and calibration of multiple devices at once.
• Macro support to handle almost unlimited test system automation.
• More complete and flexible support for accessory devices like MFC-CB (DHI mass flow controller control box).