Chu Ding HDP-01A Proportional Dilutor

Overview

The Chu Ding HDP-01A Proportional Dilutor is an electromechanical precision instrument engineered for automated, gravimetrically controlled liquid dilution in microbiological and food safety laboratories. It operates on a closed-loop proportional dilution principle: the device measures the mass of a sample placed on an integrated high-resolution balance, then calculates and dispenses a precisely defined volume of diluent—based on user-specified dilution ratios—to achieve exact mass-to-volume proportionality. Unlike volumetric or fixed-pipetting systems, the HDP-01A eliminates cumulative error from manual weighing or pipette calibration drift by anchoring dilution accuracy directly to real-time mass feedback. Its design supports ISO 6887-1, FDA Bacteriological Analytical Manual (BAM) Chapter 3, and AOAC Official Method 990.12 requirements for standardized sample preparation prior to microbial enumeration, pathogen enrichment, or toxin extraction.

Key Features

• Dual-button operational interface: Initiate weighing and diluent dispensing with minimal tactile input—reducing training time and operator variability.
• Fixed-arm dispensing architecture: Eliminates moving mechanical joints, belts, or stepper-driven actuators; enhances long-term repeatability and reduces maintenance requirements.
• Gravimetric feedback control: Continuously monitors sample mass during diluent addition and terminates dispensing at the target mass threshold, ensuring >99% volumetric delivery fidelity for 250 mL cycles.
• Microprocessor-controlled ratio logic: Supports integer dilution factors from 1/2 to 1/99, including both serial and single-step proportional modes—enabling compliance with USP & EP dilution schemes for pharmaceutical environmental monitoring.
• Automatic bag weight registration: Records tare mass of filter bags pre- and post-dilution, generating traceable metadata for GLP audit trails.
• Broad power compatibility: Dual-voltage (110 V / 220 V) and dual-frequency (50 Hz / 60 Hz) operation ensures stable performance across global laboratory infrastructure without external converters.

Sample Compatibility & Compliance

The HDP-01A interfaces seamlessly with standard stomacher-style filter bags (e.g., 400 mL polyethylene or nylon mesh bags) used in conjunction with the HMB-400 series paddle-blade homogenizers. Its 1000 g maximum load capacity accommodates viscous samples—including ground meats, dairy concentrates, and leafy produce homogenates—without requiring pre-filtration or viscosity compensation. The system complies with ISO/IEC 17025 documentation requirements for equipment calibration records and maintains full traceability of dilution parameters per sample batch. All firmware operations are deterministic and non-volatile; no user-modifiable code or configuration files exist—supporting 21 CFR Part 11 readiness when paired with compliant LIMS or ELN platforms.

Software & Data Management

While the HDP-01A operates as a standalone hardware unit with embedded microcontroller firmware, it generates timestamped, ASCII-formatted log entries (via optional RS-232 or USB-C serial output) containing: sample ID (user-entered), tare mass, net sample mass, selected dilution factor, delivered diluent mass, and completion status. These logs are compatible with common laboratory data acquisition systems and can be parsed into CSV or XML for integration into validated electronic lab notebooks (ELNs) or quality management systems (QMS). Audit trail functionality includes immutable event timestamps and operator-initiated action codes—satisfying ALCOA+ principles for data integrity in regulated environments.

Applications

• Pre-enrichment dilution of food and environmental swab samples prior to Salmonella, Listeria, or E. coli O157:H7 detection per ISO 11290 and USDA-FSIS MLG protocols.
• Standardized suspension preparation for ATP bioluminescence assays in cleanroom monitoring programs.
• Controlled dilution of clinical stool specimens for Clostridioides difficile toxin A/B immunoassays under CLIA-waived conditions.
• Reproducible matrix-matched calibration standard preparation in residue analysis workflows compliant with SANTE/11813/2017 guidelines.
• High-throughput dilution for rapid microbiological method validation studies requiring ≥30 replicate dilutions per test condition.

FAQ

Does the HDP-01A require external calibration or periodic verification?
Yes—users must perform daily balance verification using certified Class M2 weights (per ISO 9001 and ISO/IEC 17025), and annual full-system metrological validation is recommended.
Can the HDP-01A dispense multiple diluents sequentially?
No—the unit is configured for single-diluent operation only; multi-solvent protocols require manual intervention or integration with external fluid handling modules.
Is the firmware upgradable in the field?
Firmware updates are performed exclusively by authorized Chu Ding service engineers via secure diagnostic port; no end-user flash capability is provided to preserve regulatory compliance.
What safety certifications does the HDP-01A hold?
It conforms to IEC 61010-1:2010 for electrical safety in laboratory equipment and carries CE marking under the Low Voltage Directive (2014/35/EU) and EMC Directive (2014/30/EU).
How is sample cross-contamination prevented between runs?
The dispensing nozzle features a self-flushing rinse cycle (programmable duration) using the same diluent reservoir, and all wetted surfaces are constructed from autoclavable 316 stainless steel and PTFE.