Multi-Channel Proportional Dilutor HDP-01A by Tianjin HengAo

Overview

The HDP-01A Multi-Channel Proportional Dilutor is an automated liquid handling instrument engineered for precise, repeatable serial dilution in microbiological and food safety laboratories. It operates on the principle of gravimetric proportional dilution: real-time mass feedback from an integrated high-resolution balance (0.01 g resolution, up to 3000 g capacity) drives dual peristaltic pump heads to deliver exact volumes of diluent—calculated dynamically based on user-specified dilution ratios (1/2 to 1/99). Unlike volumetric dispensers, this system compensates for density variations and container tare inconsistencies, ensuring traceable, weight-based accuracy without manual calculation or pipetting. Designed for seamless integration into standardized sample preparation workflows—particularly those aligned with ISO 6887-1, FDA-BAM, and AOAC guidelines—the HDP-01A eliminates subjective operator intervention during diluent addition, thereby reducing inter-operator variability and supporting GLP-compliant documentation requirements.

Key Features

• Two independent peristaltic pump channels enable parallel or sequential dilution across multiple sample bags—ideal for high-throughput labs processing batches of food, environmental, or clinical specimens.
• Fixed-arm mechanical architecture with no moving joints or robotic arms ensures long-term stability, minimal maintenance, and consistent positioning over thousands of cycles.
• Intuitive two-button operation: tare → select ratio → initiate. No touchscreen or complex menu navigation required—reducing training time and minimizing software-related failure points.
• Onboard microprocessor performs real-time mass interpolation, automatically adjusting pump runtime to achieve target dilution accuracy (>98%) regardless of fluid viscosity or ambient temperature drift.
• Integrated weighing module logs raw bag weight before and after diluent addition, generating timestamped records compatible with laboratory information management systems (LIMS) via optional RS-232 or USB export.
• Gravimetric validation support: each dilution event includes recorded initial mass, final mass, calculated diluent mass, and applied ratio—enabling retrospective audit of dilution integrity per ISO/IEC 17025 clause 7.7.

Sample Compatibility & Compliance

The HDP-01A accommodates standard Stomacher®-compatible filter bags (e.g., 400 mL polyethylene or nylon mesh), as well as custom pouches up to 3000 g total load. Its open-platform design allows direct placement onto commercial analytical balances (Ohaus, Mettler Toledo, Sartorius) with platform dimensions ≥180 × 180 mm. The system complies with electrical safety standards IEC 61010-1 and electromagnetic compatibility per EN 61326-1. When operated in conjunction with the HMB-400 series paddle-beater homogenizers, it fulfills critical pre-homogenization steps outlined in ISO 6887-1:2017 (preparation of microbiological test samples) and USP (microbiological examination of nonsterile products). All firmware logic adheres to ALCOA+ data integrity principles, with immutable event logging suitable for FDA 21 CFR Part 11–aligned environments when paired with validated LIMS interfaces.

Software & Data Management

The HDP-01A operates without proprietary software—control and configuration are managed entirely via front-panel membrane buttons and LED indicators. All operational parameters (dilution ratio, pump calibration offsets, unit preferences) are stored in non-volatile memory. Weight and timing data are buffered internally and exportable as plain-text CSV files via USB flash drive or serial transmission. Optional firmware upgrade paths support timestamped audit trails with operator ID fields (when integrated with external badge-readers), fulfilling traceability requirements under ISO/IEC 17025:2017 section 8.4.2 and EU Annex 11 for computerized system validation. No cloud connectivity or remote access functionality is included—ensuring full data sovereignty and alignment with institutional IT security policies.

Applications

• Routine dilution of food homogenates prior to aerobic plate count (APC), coliform, or pathogen enrichment per ISO 4833-1 and FDA-BAM Chapter 3.
• Environmental water sample preparation for membrane filtration assays (ISO 9308-1) and heterotrophic plate count (HPC) analysis.
• Pharmaceutical raw material testing where USP mandates defined dilution protocols prior to microbial limit testing.
• Clinical microbiology labs performing quantitative culture of stool or wound specimens using standardized dilution matrices.
• QC/QA labs validating cleaning efficacy in pharmaceutical manufacturing—where reproducible 10-fold or custom-ratio dilutions are required for ATP bioluminescence or endotoxin recovery studies.

FAQ

Does the HDP-01A require calibration against certified weights?
Yes. Initial setup requires verification using Class M2 or better certified masses at 100 g, 500 g, and 2000 g intervals. Annual recalibration is recommended per ISO/IEC 17025 internal procedure.
Can the dilution ratio be programmed in non-integer increments (e.g., 1/3.7)?
No. The device accepts only integer denominator values from 2 to 99 (i.e., 1/2, 1/3, …, 1/99) to maintain deterministic pump control and regulatory traceability.
Is the peristaltic tubing chemically resistant to ethanol or sodium hypochlorite?
Standard tubing is silicone-based (compatible with aqueous buffers and 10% ethanol). For oxidizing agents such as hypochlorite, fluoropolymer-reinforced tubing kits are available as optional accessories.
How is compliance with 21 CFR Part 11 ensured?
The device itself does not provide electronic signatures or role-based access. However, its immutable CSV logs—when ingested into a validated LIMS with audit-trail-enabling middleware—fulfill Part 11 record retention and attribution requirements.
What maintenance is required beyond tubing replacement?
None. The fixed-arm design eliminates lubrication points, gear trains, or positional encoders. Routine checks include visual inspection of tubing wear and balance zero-stability verification every 8 hours of continuous use.