Chuanyu CHW-300BS Semi-Automatic Microbial Limit Tester with Integrated Membrane Filtration System

Overview

The Chuanyu CHW-300BS Semi-Automatic Microbial Limit Tester is an integrated membrane filtration system engineered for precise, reproducible, and contamination-controlled microbial enumeration in aqueous samples across pharmaceutical, biotechnology, food & beverage, cosmetics, and environmental monitoring laboratories. It operates on the principle of quantitative film filtration—where a defined volume of sample is drawn under controlled negative pressure through a sterile, low-protein-binding membrane (typically 0.45 µm or 0.22 µm pore size), retaining viable microorganisms on the filter surface for subsequent incubation and colony enumeration. Unlike conventional vacuum manifold systems requiring external flasks and clamps, the CHW-300BS integrates a corrosion-resistant diaphragm liquid-handling pump that directly evacuates filtrate into an internal waste reservoir, eliminating risk of overflow, cross-contamination, or vapor exposure during operation. Its compact footprint and laminar-flow-compatible design meet stringent requirements for cleanroom and biosafety cabinet integration.

Key Features

• Compact, ultra-low-profile chassis minimizes spatial demand within Class II biosafety cabinets or ISO 5 laminar flow hoods.
• Premounted, gamma-irradiated sterile membranes (Φ47 mm or Φ50 mm) are supplied pre-sterilized and ready-to-use—eliminating handling-related bioburden and reducing procedural variability.
• Lip-seal filtration head design ensures leak-tight contact between membrane, support grid, and cup without O-rings or mechanical clamps—delivering uniform filtration pressure distribution and high microbial recovery consistency (≥95% recovery verified per USP <61> validation protocols).
• Three independently actuated filtration channels enable parallel processing of heterogeneous samples (e.g., purified water, WFI, and buffer solutions) with individual start/stop control and real-time status feedback via LCD interface.
• Filtration heads are fully detachable and autoclavable (121 °C, 20 min, saturated steam); additionally compatible with rapid flame sterilization between sequential runs to maintain sterility integrity during high-throughput workflows.
• Oil-free diaphragm pump delivers stable, pulse-free vacuum up to –85 kPa with noise emission <52 dB(A), ensuring operator comfort during extended use.
• Electropolished stainless-steel base and mirror-finish housing resist microbial adhesion and facilitate validated cleaning with ethanol, benzalkonium chloride, formaldehyde, or sodium hypochlorite solutions.
• Integrated waste management eliminates need for external filtration flasks—filtrate is directed internally and retained in a sealed, removable reservoir with level sensor and overflow protection.

Sample Compatibility & Compliance

The CHW-300BS supports microbiological testing of non-viscous, low-particulate aqueous matrices including purified water (PW), water for injection (WFI), saline solutions, buffered media, soft drinks, cosmetic toners, and environmental water samples (e.g., surface water, potable water). It is not intended for strongly acidic (pH <2), strongly alkaline (pH >12), oxidizing (e.g., undiluted H₂O₂, NaOCl >5%), or highly viscous suspensions without prior centrifugation or dilution. The system complies with core regulatory frameworks governing microbial quality control: USP <61> “Microbiological Examination of Nonsterile Products: Microbial Enumeration Tests”, USP <62> “Microbiological Examination of Nonsterile Products: Tests for Specified Microorganisms”, European Pharmacopoeia 2.6.12 “Microbiological Quality of Non-Sterile Pharmaceutical Preparations”, and ISO 8573-7:2003 “Compressed air — Part 7: Viability of micro-organisms”. All wetted components are constructed from USP Class VI-certified materials.

Software & Data Management

The CHW-300BS operates as a standalone hardware platform without proprietary software dependency. All operational parameters—including date/time stamp, total runtime per channel, and pump activation history—are logged locally on the embedded LCD display. For GLP/GMP environments, users may integrate the device into broader laboratory information management systems (LIMS) via manual entry or barcode-assisted workflow documentation. While the unit does not provide electronic audit trails or 21 CFR Part 11-compliant user authentication natively, its mechanical simplicity and deterministic operation support robust validation protocols—including IQ/OQ/PQ—and full traceability when paired with standardized SOPs and paper-based or LIMS-mediated recordkeeping.

Applications

• Pharmaceutical QC labs performing routine microbial enumeration of PW and WFI per pharmacopeial monographs.
• Biologics manufacturing facilities conducting environmental monitoring of rinse waters and process streams.
• Food safety laboratories validating absence of indicator organisms (e.g., E. coli, Enterobacteriaceae) in bottled water and beverages.
• Cosmetic GMP facilities fulfilling ISO 22716-mandated microbial limits for aqueous raw materials and finished products.
• Public health laboratories executing EPA Method 1603 or ISO 9308-1 for E. coli detection in recreational and drinking water sources.
• Academic and contract research organizations conducting method suitability studies for novel antimicrobial formulations.

FAQ

What membrane diameters are supported?
The CHW-300BS accepts standard sterile filters with nominal diameters of Φ47 mm or Φ50 mm, with an effective filtration area of 40 mm diameter.
Can the filtration heads be autoclaved?
Yes—filtration assemblies are fully autoclavable at 121 °C for 20 minutes using saturated steam; verify seal integrity post-sterilization before use.
Is the system compatible with 0.22 µm pore-size membranes?
Yes—both 0.45 µm and 0.22 µm pore-size membranes are supported for bacterial retention and sterility testing applications.
How is system decontamination performed between runs?
Chemical disinfection is achieved by filtering 100 mL of validated agent (e.g., 70% ethanol, 0.1% benzalkonium chloride, or 0.5% sodium hypochlorite), holding for 3–5 minutes, followed by 200 mL sterile water rinse.
Does the instrument require external vacuum or compressed air?
No—the built-in oil-free diaphragm pump provides all necessary negative pressure; no external vacuum source or gas supply is needed.