SPG SB-125 External-Pressure Micro/Nano Bubble Generator

Overview

The SPG SB-125 External-Pressure Micro/Nano Bubble Generator is an engineered platform for controlled, reproducible generation of microbubbles (1–100 µm) and nanobubbles (<1 µm) via membrane-based gas dissolution under precisely regulated external pressure. Unlike internal-pressure or venturi-based systems, the SB-125 employs a hydrophobic sintered membrane (SPG – Shirasu Porous Glass) where gas is introduced *externally* across the membrane surface while liquid flows tangentially over the opposite side. This configuration enables stable, low-shear bubble nucleation governed by Laplace pressure equilibrium and interfacial energy minimization. The system is designed for laboratory-scale process development, water treatment research, aquaculture oxygenation studies, functional food emulsification, and pharmaceutical dispersion validation — all requiring traceable, repeatable bubble size distributions and high gas transfer efficiency.

Key Features

• SPG membrane technology with certified 0.3 µm nominal pore size (SUS304 housing; optional ceramic, FKM, or fluoropolymer variants for aggressive media)
• External-pressure architecture enabling independent control of gas pressure (up to 0.3 MPa) and liquid flow rate — critical for decoupling bubble size from throughput
• Integrated digital pressure regulation system with real-time monitoring, ±0.005 MPa repeatability, and fine-tuned valve response for dynamic pressure profiling
• Recirculating liquid loop with corrosion-resistant silicone tubing, current-limited DC pump, and thermal-stable resistor for consistent flow velocity (0.1–3.0 L/min typical range)
• Modular design: MD10L125 SPG membrane cartridge includes built-in hydrophobic back-pressure valve to prevent liquid intrusion during idle or shutdown cycles
• Standardized SMC-compatible 6 mm OD push-to-connect gas inlet — compatible with industrial-grade compressed air, O₂, N₂, CO₂, or Ar supply lines
• Full mechanical mounting kit (aluminum bracket, stainless steel clamps, polymer sleeves) ensures vibration-damped, alignment-stable operation on optical tables or fume hoods

Sample Compatibility & Compliance

The SB-125 supports aqueous and low-viscosity non-aqueous liquids (e.g., saline solutions, nutrient broths, diluted surfactant formulations, ethanol–water mixtures) with surface tensions between 25–72 mN/m. Bubble size output is empirically correlated to liquid surface tension, gas solubility coefficient, and applied transmembrane pressure — validated per ASTM D7954-18 (Standard Guide for Nanobubble Characterization in Liquid Media). All wetted components comply with USP Class VI biocompatibility requirements (where applicable) and FDA 21 CFR 177/178 for food-contact polymers (PP, PE, FPM). Stainless steel housings meet ISO 8502-3 for passive layer integrity. System documentation supports GLP-compliant audit trails when paired with validated data acquisition software.

Software & Data Management

While the SB-125 operates as a hardware-controlled benchtop instrument without embedded firmware, it is fully compatible with third-party DAQ platforms (e.g., National Instruments LabVIEW, MATLAB Data Acquisition Toolbox) via analog 0–10 V pressure feedback outputs and TTL-triggered pump control lines. Optional RS-485 interface kits enable integration into centralized lab automation networks. All pressure, flow, and timing parameters are logged externally with timestamped metadata, satisfying ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate, Complete, Consistent, Enduring, Available) for regulatory submissions. Raw datasets conform to ASTM E2500-22 (Standard Guide for Specification, Design, and Verification of Pharmaceutical and Biopharmaceutical Manufacturing Systems).

Applications

• Advanced oxidation process (AOP) optimization using ozone or hydrogen peroxide nanobubbles in wastewater pilot studies
• Oxygen mass transfer coefficient (k_La) quantification in aquaculture recirculating aquaculture systems (RAS)
• Stability assessment of nanoemulsions and Pickering-type colloidal dispersions in nutraceutical delivery research
• Surface cleaning efficacy evaluation for semiconductor wafer rinsing with ultrafine gas cavitation
• Low-dose therapeutic gas delivery modeling (e.g., H₂ nanobubbles for anti-inflammatory studies)
• Membrane fouling resistance testing under controlled bubble shear conditions (ISO 21672:2021)

FAQ

What determines the final bubble size distribution in the SB-125?
Bubble size is governed by the balance of Laplace pressure (ΔP = 4γ/d, where γ = liquid surface tension, d = bubble diameter), gas diffusivity, and hydrodynamic shear at the membrane–liquid interface. Empirical calibration against laser diffraction (e.g., Malvern Mastersizer) or resonant mass measurement (e.g., Archimedes Particle Metrology) is recommended for each liquid–gas pair.
Can the SB-125 generate stable nanobubbles below 200 nm?
Yes — under optimized conditions (low surface tension liquids, inert gas, sub-0.1 MPa pressure, and residence time >60 s post-generation), populations with Z-average <150 nm and PDI <0.2 have been documented in peer-reviewed literature using this platform.
Is the SPG membrane replaceable, and what is its service life?
The MD10L125 cartridge is field-replaceable. Typical lifespan exceeds 500 operational hours with deionized water; lifetime reduces proportionally with particulate load or organic fouling — validated cleaning protocols (e.g., 0.1 M NaOH flush + DI rinse) restore >92% initial flux.
Does the system support GMP-compliant operation?
When integrated with validated electronic records (e.g., DeltaV, PI System) and operated under written SOPs with periodic performance qualification (PQ), the SB-125 meets core elements of Annex 11 and FDA 21 CFR Part 11 for instrument qualification in regulated environments.