Precision Laboratory Gas Mixing for a Leading CRO: A Multi-Component Dynamic Gas Dilution System Case Study

Contents

Executive Summary

Key Design Optimizations

Customer Requirements

Key Engineering Challenges

Challenge 1: Dual output requirement

Challenge 2: Cleanroom hygiene compliance

Challenge 3: 1:1000 mixing ratio with low-flow precision

MR-DF2 System Configuration

Gas path configuration

Output configuration

Alarm protection

HMI and data management

Specification Compliance Summary

Core Technical Parameters

Validation and Service

Items Pending Customer Confirmation

Why This Matters for Laboratories and Dealers

About Beijing Airppb

Executive Summary

Key Design Optimizations

This solution incorporates three critical optimizations based on the customer's technical requirements:

1. Optimized MFC Configuration: Air and oxygen channels use 10 L/min MFCs, while CO₂ employs a 1 L/min high-precision MFC with minimum controllable flow of 5 mL/min, achieving a dilution ratio of 2000:1 — exceeding the 1:1000 requirement.

1. Clarified Dual Output Implementation: The current design provides relay-controlled alternating dual output (Output 1 OR Output 2). Simultaneous dual output would require design modifications and is listed as a pending confirmation item.

1. Verified Parameter Compliance: All specification claims have been recalculated and verified against actual performance, with conditional compliance clearly noted where applicable.

Customer Requirements

The customer operates a cleanroom laboratory environment that demanded both precision and compliance. The core requirements:

Key Engineering Challenges

Figure 2. Dilution ratio design. The 1 L/min high-precision CO2 MFC reaches a minimum controllable flow of 5 mL/min, giving 1:2000 against a 1:1000 requirement.

Challenge 1: Dual output requirement

The customer wanted two independent mixed-gas outputs so one instrument could serve two workstations or two incubators.

Current Solution: The MR-DF2 itself is designed with dual output capability, fully meeting the customer's usage requirements.

Challenge 2: Cleanroom hygiene compliance

Wetted parts had to survive routine disinfection with 75% ethanol and sodium hypochlorite.

Solution:

· All gas-path components — MFC valve bodies, fittings — are 316L stainless steel, electropolished

· Gas tubing uses silane-passivated tubing design to minimize CO₂ adsorption and improve trace gas accuracy

· Seals use EPDM/PTFE, resistant to routine disinfectants

· This configuration meets hygiene standards for cleanroom use while optimizing trace gas performance

Figure 3. Cleanroom wetted-part material stack: 316L stainless steel, silane-passivated tubing and EPDM/PTFE seals.

Challenge 3: 1:1000 mixing ratio with low-flow precision

To generate 1,000 ppm CO₂ from pure CO₂, the dilution ratio is 1000:1. The smallest controllable flow must be ≤ 10 mL/min.

Optimized Solution:

· Air and oxygen channels: 10 L/min MFCs each, meeting "≥10 L/min per channel" and "≥20 L/min combined output"

· CO₂ channel: 1 L/min high-precision MFC, minimum controllable flow ≈ 0.5% F.S. = 5 mL/min

· Dilution ratio: 10 L/min air ÷ 5 mL/min CO₂ = 2000:1, exceeding the 1:1000 requirement

· Combined output: Air 10 L/min + Oxygen 10 L/min = 20 L/min (CO₂ trace addition negligible)

Calculation Example:

· Air (diluent): 10 L/min

· Oxygen (feed/balance gas): 10 L/min

· CO₂ (feed gas): 5 mL/min (1 L/min MFC operating at 0.5% F.S.)

· CO₂-to-air ratio = 5 mL ÷ 10,000 mL = 1:2000 ≥ 1:1000 ✓

MR-DF2 System Configuration

Figure 1. MR-DF2 gas path configuration for the CRO application: three gas channels, three MFCs, mixing chamber and dual output.

Gas path configuration

Note: Silane-passivated tubing reduces CO₂ adsorption compared to all-metal tubing, improving trace gas accuracy while maintaining chemical resistance.

Output configuration

Output	Flow range	Material	Control
Output 1	0–20 L/min	Silane-passivated tubing	Existing design
No. 11 Kechuang 14th Street, Beijing Economic and Technological Development Zone, Beijing, China E-mail: icelb1983@gmail.com Tel: +86 13439052733 Tel: +86 13439052733 The Largest R&D and Production FTIR Gas Analyzer Supplier in China 861343905273 +86 13439052733 Privacy Policy | sitemap | China Good Quality FTIR Gas Analyzer supplier. 2026 Beijing Airppb Environmental Protection Equipment Co., Ltd. . All Rights Reserved.