HUANKONG GHK-7500 Digital Gas Flow Measurement and Control System

Overview

The HUANKONG GHK-7500 Digital Gas Flow Measurement and Control System is a precision metrological instrument engineered for the calibration and verification of low-flow gas flowmeters in laboratory and metrology institute environments. It operates on a digitally regulated positive/negative pressure generation principle, utilizing a piston-driven constant-flow air source coupled with high-resolution digital flow sensing technology. Unlike conventional calibration setups requiring bulky auxiliary equipment—such as bell prover systems, compressed air receivers, vacuum pumps, or pressure stabilization tanks—the GHK-7500 integrates all core functions into a compact, self-contained architecture. Its design conforms to fundamental fluidic metrology principles, enabling traceable volumetric flow measurement under controlled thermobaric conditions. The system supports dual-mode operation: positive-pressure mode for calibrating soap film meters, rotameters, and thermal mass flowmeters; and negative-pressure (vacuum) mode for orifice-type flowmeter verification. All measurements are referenced to four standardized gas state definitions—actual operating conditions, standard conditions at 273.15 K and 101.325 kPa, standard conditions at 293.15 K and 101.325 kPa, and reference conditions at 298.15 K and 101.325 kPa—ensuring full compliance with international gas volume normalization conventions.

Key Features

• Integrated digital flow control module with programmable setpoint input—eliminates manual flow adjustment and enables repeatable, stepwise calibration sequences
• Dual-mode pressure generation: electronically stabilized positive pressure (up to +100 kPa gauge) and negative pressure (down to –95 kPa gauge) for comprehensive flowmeter coverage
• Onboard temperature and pressure sensing: simultaneous measurement of ambient temperature, pre-meter temperature, atmospheric pressure, and pre-meter pressure with automatic compensation
• Full-state volumetric flow calculation: real-time conversion and display of flow rates in operational, NTP (273.15 K), STP (293.15 K), and reference (298.15 K) conditions
• End-to-end digital traceability: integrated microcontroller-based data acquisition platform with timestamped storage, error-checking algorithms, and GLP-compliant audit trail generation
• Factory-calibrated system-level accuracy: eliminates need for separate pressure and temperature transducer calibration prior to metrological use—supports in-situ full-system verification per JJG requirements

Sample Compatibility & Compliance

The GHK-7500 is validated for calibration of Class 1 accuracy gas flow instruments, including soap film flowmeters (JJG 586–2006), orifice flowmeters (JJF 2033–2023), variable-area (rotameter) devices (JJG 257–2007), and thermal mass flowmeters (JJG 1132–2017). Its flow range and stability characteristics align with ISO 4064-2:2014 (water meters) and ISO 6789-2:2017 (torque tools) metrological frameworks, adapted for gaseous media. While designed for domestic metrological standards, its thermodynamic modeling engine supports user-defined gas properties and compressibility corrections (Z-factor), facilitating adaptation to ASTM D3588–98 (natural gas energy content) and ISO 5167–1:2003 (differential pressure flow) workflows. All firmware and data handling modules comply with basic data integrity principles aligned with FDA 21 CFR Part 11 Annex 11 expectations for electronic records.

Software & Data Management

The embedded microcontroller firmware implements deterministic real-time sampling at ≥10 Hz, with 16-bit ADC resolution for analog sensor inputs. Data is stored locally in non-volatile memory with cyclic redundancy check (CRC-32) validation. Optional PC connectivity via RS-232 or USB-C enables bidirectional communication using ASCII-based command protocol. The companion software (Windows-compatible, no runtime dependencies) provides automated report generation in PDF and CSV formats, with configurable certificate templates compliant with ILAC-P14 and CNAS-CL01:2018 documentation requirements. Audit logs record operator ID, calibration date/time, environmental parameters, raw sensor outputs, correction coefficients applied, and final certified values—with immutable timestamps and digital signature placeholders for authorized sign-off.

Applications

• Primary calibration of low-flow gas flowmeters in provincial and municipal metrology institutes
• Verification of environmental monitoring analyzers (e.g., NO_x, SO₂, VOC samplers) requiring precise sample draw rate control
• Quality assurance testing of medical gas delivery devices (e.g., anesthesia vaporizers, ventilator flow sensors)
• R&D support for gas sensor development labs needing stable, programmable flow profiles across multiple gas species
• Validation of cleanroom airflow hoods and laminar flow cabinets per ISO 14644-3:2019 Annex B

FAQ

Does the GHK-7500 require external pressure regulators or vacuum pumps?

No—the system incorporates an integrated piston pump and digital pressure regulation circuitry, eliminating dependency on external pneumatic infrastructure.
Can it calibrate flowmeters using gases other than air?

Yes—users may input custom gas composition and compressibility factors to adjust density and viscosity calculations accordingly.
Is the system suitable for field use or only laboratory environments?

It is designed for controlled laboratory settings; environmental operating limits are 15–30 °C ambient temperature and ≤80% RH non-condensing.
How is traceability maintained without external calibration of individual sensors?

The GHK-7500 undergoes full-system calibration at the manufacturer’s ISO/IEC 17025-accredited facility, with documented uncertainty budgets for combined flow, temperature, and pressure measurements.
What data export formats are supported?

Raw time-series data (CSV), calibrated results (CSV), and formal calibration certificates (PDF) with digital watermarking and optional electronic signature integration.