SevenStar D07-7CM Thermal Mass Flow Meter

Overview

The SevenStar D07-7CM Thermal Mass Flow Meter is an industrial-grade, analog-output gas mass flow measurement instrument engineered for high-reproducibility quantitative gas delivery and process monitoring in controlled environments. It operates on the principle of constant-temperature anemometry (CTA), where a heated sensing element—typically a platinum RTD or micro-machined thermal resistor—is maintained at a fixed temperature differential relative to the ambient gas stream. As gas flows across the sensor, convective heat transfer alters the power required to sustain that temperature difference; this electrical power change is linearly correlated to the mass flow rate. Unlike volumetric flowmeters, the D07-7CM directly measures mass flow without requiring real-time pressure or temperature compensation, making it inherently suitable for applications where gas composition remains stable (e.g., N₂, Ar, O₂, He, CO₂, and common process gases). Calibrated using nitrogen under standard conditions (0 °C, 101.325 kPa), its readings are traceable to SI-based mass flow units (SCCM, SLM), ensuring compatibility with international metrological frameworks including ISO 8503-2 and ASTM E2653 for thermal flow instrumentation.

Key Features

• Tubular bypass architecture—minimizes pressure drop (<0.01 MPa) while extending service life through reduced sensor exposure to particulates and condensates
• Fully analog signal path with 0–5.00 V DC output, optimized for integration into legacy PLC, DCS, and PID control systems without digital protocol conversion
• High repeatability (±0.2 % F.S.) and linearity (±1 % F.S.), validated per IEC 61298-2 procedures for analog transmitters
• Robust mechanical construction featuring fluorocarbon (FKM) or chloroprene elastomer seals—rated for helium leak integrity ≤1×10⁻⁸ atm·cm³/s, meeting vacuum compatibility requirements per ISO 2859-1 sampling plans
• CE-marked electromagnetic compatibility—tested to EN 61326-1 for industrial environments with conducted/radiated immunity up to 10 V/m
• Standard DB15 female connector and multiple wetted-end connection options (VCR 1/4″, Swagelok 1/4″, φ3/φ4/φ6 stainless steel tubing) enabling rapid installation in semiconductor tooling, vacuum coating chambers, and analytical gas supply manifolds

Sample Compatibility & Compliance

The D07-7CM is designed for clean, dry, non-corrosive, and non-particulate gas streams. Its calibration is referenced to nitrogen; for other gases, optional correction factors (based on specific heat ratio and thermal conductivity) may be applied per manufacturer-provided gas coefficient tables. While not intrinsically safe or explosion-proof certified, it complies with general-purpose industrial safety standards when installed per IEC 60079-14 guidelines. The device supports GLP/GMP-aligned operation through stable analog output and documented calibration history; though it lacks built-in audit trail functionality, its analog interface allows seamless integration with compliant data acquisition systems supporting FDA 21 CFR Part 11 electronic record requirements when paired with validated software and hardware timestamping.

Software & Data Management

As a standalone analog transmitter, the D07-7CM does not incorporate embedded firmware, display, or digital communication protocols (e.g., RS-485, Modbus, or EtherNet/IP). Its 0–5.00 V output is intended for direct routing to external analog input modules in programmable logic controllers (PLCs), data loggers, or SCADA systems. Users retain full ownership of data handling workflows—including scaling, unit conversion, alarm triggering, and long-term archival—within their existing infrastructure. For laboratories requiring traceable calibration documentation, SevenStar provides factory calibration certificates referencing NIST-traceable nitrogen standards, including as-found/as-left data, uncertainty budgets, and environmental test conditions (temperature, barometric pressure).

Applications

• Precise gas dosing in plasma-enhanced chemical vapor deposition (PECVD) and sputtering systems
• Process gas monitoring in semiconductor etch and cleaning tools (e.g., NF₃, Cl₂, SF₆ delivery)
• Carrier and purge gas control in fiber optic preform fabrication and laser crystal growth furnaces
• Calibration reference flow in gas chromatography (GC) carrier gas loops and breath analysis analyzers
• Mass flow verification in medical gas mixing systems (ISO 8573-1 Class 2 compressed air, oxygen, nitrous oxide)
• Research-scale gas blending for catalytic reaction studies and fuel cell testing rigs

FAQ

Is the D07-7CM suitable for use with corrosive gases such as HCl or ClF₃?
No. The wetted materials—stainless steel body, FKM/Neoprene seals, and platinum-based sensor—are incompatible with strongly oxidizing or halogenated corrosives. Use only with chemically inert or mildly reactive gases listed in the manufacturer’s compatibility matrix.
Can the device be recalibrated for a gas other than nitrogen?
Yes—via application of certified gas-specific correction factors provided by SevenStar. However, recalibration requires revalidation against traceable standards for the target gas; field recalibration is not supported.
What is the maximum allowable upstream/downstream pressure differential?
The specified pressure drop across the meter must remain below 0.01 MPa during operation. Exceeding this limit may degrade linearity and accelerate thermal drift.
Does the D07-7CM meet vacuum system leak-integrity requirements for UHV applications?
It meets helium leak rate specifications (≤1×10⁻⁸ atm·cm³/s) appropriate for high-vacuum (HV) systems (10⁻⁶ to 10⁻⁷ mbar), but is not rated for ultra-high vacuum (UHV, <10⁻⁹ mbar) due to outgassing characteristics of elastomeric seals.
Is there a digital version of the D07-7CM available?
SevenStar offers digitally enhanced variants (e.g., D07-7C series with RS-485/Modbus) for networked deployments; however, the D07-7CM remains strictly analog-output to ensure deterministic response timing and EMI resilience in electrically noisy tool environments.