Hershey ES5000-4 Intelligent Balancing Scale

Overview

The Hershey ES5000-4 Intelligent Balancing Scale is a dedicated multi-pan weighing system engineered for precise mass matching of blood collection bags prior to centrifugation in clinical transfusion laboratories and blood bank processing facilities. Unlike general-purpose analytical or precision balances, the ES5000-4 operates on a comparative static-load balancing principle—simultaneously measuring and digitally displaying the mass differential across four independent load cells—to ensure symmetrical loading of low-speed refrigerated centrifuges. This function directly addresses a critical operational requirement: minimizing mechanical stress on centrifuge rotors caused by unbalanced loads, which can compromise separation efficiency, accelerate bearing wear, and introduce safety hazards during high-G-force operation. The device is not a replacement for metrological-grade mass measurement but a purpose-built process instrument designed for rapid, repeatable, and traceable load equalization under routine blood component manufacturing conditions.

Key Features

• Four independently calibrated stainless-steel weighing pans (175 × 175 mm each), optimized for simultaneous placement of standard blood bags (up to 500 mL whole blood units) and ancillary containers.
• Dual-function capability: real-time differential mass display for balancing + absolute mass readout per pan for documentation and batch record generation.
• Microprocessor-based control with 1 g readability and ≤1 g repeatability across the full 0–5000 g range per pan, validated under ISO 9001-controlled manufacturing conditions.
• Fast stabilization time of ≤1.5 seconds ensures throughput alignment with high-volume blood processing workflows (e.g., platelet-rich plasma or cryoprecipitate preparation).
• Integrated environmental compensation: automatic temperature drift correction (0.005 %/°C sensitivity stability) within the specified 10–35 °C operating range.
• Manual calibration protocol compliant with internal quality procedures; supports user-performed span and zero-point verification using certified reference masses.

Sample Compatibility & Compliance

The ES5000-4 accommodates standard polyolefin and PVC blood bags—including CPD/CP2D/AS-1/AS-3 anticoagulant systems—as well as secondary containers used in pathogen reduction or leukoreduction workflows. Its large pan surface and low-profile design prevent bag tipping or leakage during loading. From a regulatory perspective, the scale meets functional requirements outlined in AABB Standard 5.12.1 (Centrifuge Load Balancing), CLSI GP44-A4 (Procedures for the Handling and Processing of Blood Components), and EU Directive 2002/98/EC Annex III (Good Manufacturing Practice for Blood Establishments). While not certified to OIML R76 or NIST Handbook 44, its performance parameters align with in-house validation protocols required for GLP and GMP-aligned blood banking operations.

Software & Data Management

The ES5000-4 operates as a standalone hardware unit with no embedded data logging or network interface. However, its RS-232 serial output (optional cable kit available) enables connection to laboratory information systems (LIS) or electronic batch record (EBR) platforms for automated capture of balance readings and differential values. All displayed data—including individual pan masses, net imbalance, timestamp (when externally synchronized), and operator ID—can be exported in ASCII format for audit trail generation. When integrated into validated workflows, the system supports 21 CFR Part 11 compliance through external software controls governing user authentication, electronic signatures, and audit log retention.

Applications

• Blood bank centrifuge load balancing for red blood cell, platelet, and plasma fractionation.
• Pre-centrifugation weight matching of paired blood bags in double-spin or buffy coat methods.
• Quality control checks for anticoagulant-to-blood volume ratio consistency across donor units.
• Supporting automated blood component labeling systems requiring verified mass inputs before seal integrity testing.
• Calibration support for volumetric fill verification in closed-system component processing lines.

FAQ

Is the ES5000-4 suitable for ISO/IEC 17025 accredited calibration labs?
No—it is not designed for primary mass calibration or traceable metrology; it serves as a process-balancing tool meeting clinical workflow requirements.
Can the scale be used outside blood banking applications?
Yes, provided the application requires simultaneous multi-container mass comparison within ±1 g tolerance and does not demand legal-for-trade certification.
What maintenance is required beyond manual calibration?
Routine cleaning with 70 % ethanol; annual verification of load cell linearity and pan-leveling using certified test weights is recommended.
Does the device include built-in audit trail functionality?
No—audit trails must be generated externally via LIS/EBR integration or manual recording per SOP.
Are replacement pans or custom pan inserts available?
Yes—Hershey offers optional silicone-coated pans and anti-slip inserts compatible with the ES5000-4 mechanical interface.