SevenStar D07-19CM Thermal Mass Flow Meter

Overview

The SevenStar D07-19CM is a precision thermal mass flow meter engineered for stable, real-time measurement of gas mass flow rates under controlled process conditions. Unlike volumetric flowmeters, it operates on the principle of constant-temperature anemometry: two platinum resistance temperature detectors (RTDs) are embedded in the flow path—one heated, one unheated—forming a thermal sensor bridge. As gas flows across the heated element, convective heat transfer alters the temperature differential between the sensors, generating a voltage signal linearly proportional to mass flow rate. This method eliminates dependence on pressure and temperature fluctuations when referenced to standardized conditions (0 °C, 101.325 kPa), making the D07-19CM particularly suitable for applications requiring traceable, repeatable gas delivery in vacuum-compatible or low-pressure environments.

Key Features

• Thermal-based measurement architecture with dual-platinum RTD sensing elements for high long-term stability and minimal zero drift
• Analog output signal (0–5.00 V DC) directly proportional to mass flow, compatible with PLCs, DAQ systems, and PID controllers without additional signal conditioning
• Robust mechanical design featuring multiple sealing material options—FKM, PTFE, and CR—to ensure chemical compatibility across aggressive process gases including NH₃, Cl₂, HCl, O₂, Ar, and He
• CE-certified electromagnetic compatibility (EMC) for reliable operation in industrial control cabinets and semiconductor tool environments
• Standardized DB15 male electrical interface and internationally recognized mechanical connection options (VCR, Swagelok, and metric tube fittings) enabling seamless integration into existing gas distribution systems
• Fast dynamic response (<1.5 s) and excellent repeatability (±0.2% F.S.) support closed-loop process control and rapid gas switching protocols

Sample Compatibility & Compliance

The D07-19CM is calibrated using nitrogen (N₂) as the reference gas under ISO 6551 and ASTM D3588 standard conditions (0 °C, 101.325 kPa). While factory calibration is performed on N₂, built-in gas correction factors allow accurate measurement of other gases—including argon, helium, oxygen, hydrogen, and carbon dioxide—via user-configurable scaling coefficients. The device meets ISO 9001 manufacturing quality requirements and complies with CE marking directives for electromagnetic immunity (EN 61326-1) and low-voltage safety (EN 61010-1). Its leak integrity—verified at ≤1×10⁻⁹ SCCS He—ensures suitability for ultra-high-purity (UHP) gas handling in semiconductor fabrication, optical fiber preform synthesis, and analytical instrument carrier gas supply. All wetted materials are documented per ASME BPE and meet USP Class VI biocompatibility criteria where applicable.

Software & Data Management

The D07-19CM operates as a standalone analog transducer and does not require proprietary software or firmware updates. Its 0–5 V output is inherently compatible with industry-standard data acquisition platforms (e.g., National Instruments LabVIEW, Keysight PathWave, or Beckhoff TwinCAT). For system-level traceability, users may integrate the meter into validated environments compliant with FDA 21 CFR Part 11 by logging output signals alongside timestamped metadata in audit-trail-enabled SCADA or MES systems. Optional analog-to-digital conversion modules with built-in linearization and temperature compensation are available from authorized SevenStar system integrators for enhanced metrological rigor in GLP/GMP-regulated laboratories.

Applications

• Precise gas dosing in plasma-enhanced chemical vapor deposition (PECVD) and sputtering tools
• Carrier and purge gas control in gas chromatography (GC) and residual gas analyzers (RGA)
• Process gas monitoring in pharmaceutical lyophilization and sterilization cycles
• Flow verification in calibration laboratories performing ISO/IEC 17025-accredited gas flow instrument verification
• Gas blending and mixture ratio control in specialty gas production facilities
• In-line flow validation for cleanroom environmental monitoring systems

FAQ

Is the D07-19CM suitable for use with corrosive gases such as chlorine or hydrogen chloride?

Yes—when configured with fluorocarbon (FKM) and PTFE seals, the D07-19CM maintains integrity and accuracy in chemically aggressive gas streams. Consult the material compatibility chart prior to installation.
Does the meter require external temperature or pressure compensation?

No—the thermal mass flow principle inherently measures mass flow independent of ambient T/P variations; however, output is referenced to standard conditions (0 °C, 101.325 kPa), so no real-time compensation is needed for reporting.
Can the device be used in vacuum environments?

It is rated for operation up to 10 MPa burst pressure and functions reliably at inlet pressures down to 1 kPa absolute, provided the pressure drop across the sensor remains below 0.02 MPa.
What is the recommended recalibration interval?

Annual calibration is advised for critical applications; however, field verification using a primary standard (e.g., bell prover or laminar flow element) can extend intervals per ISO/IEC 17025 internal procedures.
Is digital communication (e.g., RS-485 or Modbus) available?

The base D07-19CM model provides only analog output. Digital variants (e.g., D07-19CM-D) with RS-485/Modbus RTU are available upon request through authorized distributors.