Huake Instrument HK-5500 Closed-Circuit Deionized Water Cooling Unit

Overview

The Huake Instrument HK-5500 Closed-Circuit Deionized Water Cooling Unit is an engineered thermal management system designed for continuous, contamination-free cooling of high-temperature sample racks—commonly deployed in power plant chemistry monitoring systems, particularly in fossil-fueled and nuclear generating units with rated capacities from 50 MW to 600 MW. Unlike open-loop industrial water cooling, the HK-5500 maintains a fully isolated deionized (DI) water loop that circulates through the hot sample rack while rejecting heat via a secondary industrial water circuit. This separation prevents scaling, corrosion, and ionic contamination of critical analytical instrumentation—ensuring long-term integrity of online conductivity, pH, dissolved oxygen, and cation conductivity sensors. The unit operates on the principle of indirect heat transfer using a gasketed plate-and-frame heat exchanger, enabling high thermal efficiency without direct contact between process-grade DI water and utility-grade cooling water.

Key Features

• Compact skid-mounted architecture integrating heat exchangers, dual centrifugal pumps, DI water reservoir, filtration, level sensing, and control logic into a single ISO-standard footprint (3200 × 2000 × 2300 mm).
• Gasketed plate heat exchangers with weld-free construction—each unit comprises two independent modules (2 × 15–2 × 30 m² total effective area)—allowing modular cleaning, plate count adjustment, and field serviceability without welding or brazing.
• Dual-pump configuration with automatic failover: primary pump operates under normal load; standby pump engages within <2 seconds upon pressure drop or motor fault detection, maintaining ≥0.2 MPa outlet pressure at all times.
• AISI 304 stainless steel wetted components—including pump casings, piping, valves, and tank interior—guarantee resistance to chloride-induced stress corrosion cracking and compatibility with ultra-low conductivity (<0.1 µS/cm) DI water.
• Integrated filtration: Y-type strainers installed upstream of both industrial water inlet and pump suction lines (mesh size: 100 µm) prevent particulate ingress and protect heat exchanger plates and impeller vanes.
• Intelligent level management: ultrasonic level transmitters monitor DI water volume (2 m³ tank); low-level condition triggers solenoid valve refill, while high-level alarm inhibits further addition and initiates visual/audible notification.

Sample Compatibility & Compliance

The HK-5500 is purpose-built for use in regulated thermal power generation environments where analytical data traceability and system reliability are governed by national and international standards. It supports continuous operation in accordance with DL/T 561–2013 (Guidelines for Chemical Supervision of Thermal Power Plants), GB/T 12145–2016 (Water and Steam Quality Standards for Thermal Power Units), and aligns with IEC 61511 functional safety requirements for safety instrumented systems (SIS) in auxiliary cooling loops. All electrical components meet IP54 ingress protection rating; control wiring complies with IEC 60204-1. No consumables or chemical additives are required—the system relies solely on physical heat exchange and mechanical redundancy to ensure uninterrupted cooling of high-value sample conditioning hardware.

Software & Data Management

The HK-5500 operates as a standalone electro-mechanical system with hardwired interlocks and relay-based logic—no embedded software or network interface is included in base configuration. Optional integration with plant DCS or SCADA systems is supported via 4–20 mA analog outputs (DI water outlet temperature, pressure, tank level) and dry-contact status signals (pump running, alarm active, refill engaged). All operational events—including pump switchovers, level excursions, and filter differential pressure exceedances—are logged locally via time-stamped relay closures compatible with third-party historian systems. While not FDA 21 CFR Part 11 compliant out-of-the-box (as no electronic recordkeeping is performed internally), audit trails generated by external supervisory systems retain full ALCOA+ attributes when configured per GAMP 5 guidelines.

Applications

• Cooling of high-temperature sample racks in online water chemistry monitoring systems for drum-type and once-through boilers.
• Thermal stabilization of steam condensate sampling lines in nuclear secondary circuits (PWR/BWR) to preserve representative speciation prior to ion chromatography or conductivity analysis.
• Supporting continuous operation of online cation conductivity analyzers where temperature-sensitive membrane electrodes require stable sub-35 °C inlet conditions.
• Backup cooling for turbine lube oil coolers during transient startup/shutdown phases where DI water purity must be preserved across multiple process trains.
• Integration into closed-loop chemical feedwater conditioning skids where cross-contamination between cooling and process circuits is strictly prohibited.

FAQ

What is the maximum allowable temperature differential between industrial cooling water and deionized water?

The unit is rated for a maximum log mean temperature difference (LMTD) of 12 K. For optimal fouling resistance, maintain industrial water inlet temperature ≤33 °C and DI water return temperature ≤45 °C.
Can the HK-5500 be retrofitted with remote monitoring capability?

Yes—via optional 4–20 mA signal conditioning modules and Modbus RTU gateway kits. Integration requires site-specific protocol mapping and isolation transformers for grounding compliance.
Is the stainless steel grade suitable for coastal installation environments?

AISI 304 provides adequate corrosion resistance in inland or moderately aggressive atmospheres. For marine or high-chloride ambient exposure, upgrade to AISI 316L is recommended and available under custom order.
How often does the plate heat exchanger require maintenance?

Under typical power plant operating conditions (industrial water turbidity <5 NTU, hardness <100 ppm CaCO₃), inspection and gasket replacement are scheduled every 24 months; plate cleaning frequency depends on pre-filter performance and is typically biannual.
Does the unit include flow balancing valves for parallel operation?

No—flow balancing is achieved externally via system-level header design. The HK-5500 is intended for dedicated single-rack service; multi-rack configurations require separate units or engineered manifold solutions.