With over 40 years experience of designing and building high integrity test and calibration systems, Chell's team of mechanical, electronic and software engineers are ready to design and build solutions for your R&D and production test and calibration applications.
Chell provides customers with a comprehensive calibration service covering all measurement instruments supplied by the company.
Chell Instruments offer a wide range of high quality and reliable mass flow meters, controllers and systems suitable for use in a wide range of applications and industries.
With over 40 years of experience in flow measurement and control, we are extremely well placed to assist in specifying and supplying instumentation for your application, from single instruments to bespoke automated systems. Chell's impressive calibration and repair facilities also allow us to offer comprehensive after sales support.
Chell Instruments are the UK distributor for the 'SAES Pure Gas' range of gas purification equipment. These offer incredible purification performance over a huge range of gases and flow rates through the use of absorber, adsorber, catalyst, heated getter and palladium membrane purification technologies.
We also supply a range of gas handling solutions, from full, bespoke gas panels to high performance needle valves and regulators.
Chell offer a wide range of equipment for the measurement and control of gas pressure. This could be a very high-end primary pressure standard, benchtop calibrator, portable calibrator or simply a single transducer. We can also provide bespoke, automated pressure measurement systems tailored to your exact process requirements.
Chell's impressive calibration and repair facilities also allow us to offer comprehensive after sales support.
Chell supply a range of temperature scanners to complement the pressure scanners
Chell Instruments offer a wide range of high quality and reliable vacuum measurement instrumentation for use in a huge variety of applications and industries.
With over 30 years of experience in vacuum measurement and control, we are extremely well placed to assist in specifying and supplying instrumentation for your application, from single instruments to bespoke automated systems.
Chell's impressive calibration and repair facilities also allow us to offer comprehensive after sales support.
molbloc flow elements are connected to molbox RFM Flow Monitors with two pressure connections and one data line. molbox RFM Flow Monitors read calibration data off the molbloc EEPROM and measures molbloc upstream and downstream pressure with a built-in high accuracy Reference Pressure Transducers (RPTs). An ohmic measurement system reads the resistance of the molbloc platinum resistance thermometers from which molbloc temperature is calculated. Using the molbloc calibration data, pressures, temperature and gas properties stored in molbox RFM memory, the flow rate of the gas flowing through the molbloc is calculated. For molbloc-L flow elements, a microrange option is available to increase flow measurement resolution and accuracy under 10 % FS of the flow range.
Flow Measurement Specifications
molbox RFM measures the flow through molbloc flow elements. The flow range, usable operating pressure, and differential pressure for molbloc-L, or the flow range and absolute pressure range for molbloc-S, depend on the molbloc element used and its calibration options. See the molbloc-L and molbloc-S range sheets for calibration and range details.
For molbloc-L ranges up to 3E4, the resolution and accuracy under 10% FS are improved by the microrange option. For the 1E5-L molbloc, the microrange option is necessary to achieve the specification.
molbox RFM Reference Flow Monitors |
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molbloc-L (ranges 1E1-L thru 3E4-L) |
molbloc-S (all ranges) |
Measurement update rate
|
1 second |
1 second |
Range |
to molbloc full scale depending on gas and molbloc pressure dependent calibration type (see molbloc-L range sheet) |
The flow related to 20 kPa to 200 kPa absolute (3 psia to 30 psia) or 50 kPa to 500 kPa absolute (7 psia to 70 psia) upstream (see molbloc-S range sheet) |
Resolution |
0.01 % FS |
± 0.01 % of reading |
Linearity |
± 0.23 % of reading from 10 % to 100 % FS, ± 0.023 % FS under 10 % FS |
± 0.25 % of reading |
Repeatability |
± 0.1% of reading from 10 % to 100 % FS, ± 0.01% FS under 10 % FS |
± 0.1 % of reading |
Precision1 |
± 0.25 % of reading from 10 % to 100 % FS, ± 0.025 % FS under 10 % FS |
± 0.3 % of reading |
Predicted stability2 |
± 0.15 % of reading from 10 % to 100 % FS, ± 0.015 % FS under 10 % FS |
± 0.2 % of reading |
Measurement uncertainty3
|
± 0.5 % of reading from 10 % to 100 % FS, ± 0.05 % FS under 10 % FS |
± 0.5 % of reading from 50 kPa to 500 kPa, ± 0.5 % of the flow @ 50 kPa from 20 kPa to 50 kPa |
molbox RFM with Microrange option |
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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 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 |
± 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 |
Specifications are the same as a molbox RFM without Microrange. The Microrange transducer is disabled whenever the molbox RFM is connected to a molbloc-S.
1 Precision: Combined linearity, hysteresis, repeatability.
2 Predicted Stability: Maximum change in zero and span over one year for typical molbox RFM and molbloc used under typical conditions. As stability can only be predicted, stability for a specific molbox RFM should be established from experience.
3 Measurement Uncertainty: Maximum deviation of the molbox RFM flow indication from the true value of the flow through the molbloc including precision, stability and DHI calibration standard uncertainty. Measurement uncertainty specifications for molblocs are valid only for gases with which the molbloc has been calibrated. All molblocs are calibrated for N2. Calibrations with other gases are optional. DHI calibration capability is not maintained at all times for all gases on all molbloc designations. Check for availability before ordering.