HK-5300 Series Chemical Dosing System by Huake Instrument

Overview

The HK-5300 Series Chemical Dosing System is an engineered solution for precise, reliable, and adaptive chemical injection in high-integrity industrial water treatment processes—specifically tailored for boiler feedwater, drum water, condensate polishing, and circulating cooling water systems. Built upon a modular architecture, the system implements closed-loop process control using real-time analog inputs (e.g., pH, conductivity, dissolved oxygen, phosphate concentration) from field-mounted analyzers. Its core control logic integrates dual-mode algorithmic regulation: a primary PID controller for rapid setpoint convergence and a secondary fuzzy inference engine to handle nonlinear load variations—such as transient steam demand shifts or feedwater quality fluctuations—without integral windup or overshoot. This hybrid approach ensures stable dosing performance across dynamic operational envelopes, meeting the stringent repeatability requirements of ASME PTC 19.11 (Performance Test Codes for Feedwater Treatment Systems) and ISO 14690-1 (Risk Management for Process Industries). The system operates within Class II, Division 2 hazardous location environments when configured with appropriate enclosures (NEMA 4X/IP66), and supports seamless integration into plant-wide automation via Modbus RTU/TCP or Profibus DP interfaces.

Key Features

• Modular unit design: Configurable as single-pump–single-tank, dual-pump–single-tank, triple-pump–dual-tank, or quad-pump–dual-tank assemblies—enabling scalability from small industrial boilers to multi-unit power plants.
• Variable-frequency drive (VFD)-controlled metering pumps: Enables continuous, stepless flow adjustment across the full operating range (0.1–100% stroke), delivering ±1.5% volumetric accuracy per ISO 10628 and maintaining dosing linearity under variable backpressure conditions up to 16.0 MPa.
• Redundant safety architecture: Includes low-low level pump interlock, spring-loaded pressure relief valves with certified lift capacity, automatic pump switchover between primary and standby units, and fail-safe valve positioning logic during signal loss.
• Multi-mode operation: Hardware-locked manual, soft-manual (operator-adjustable setpoint override), and fully automatic modes—each mutually exclusive to prevent conflicting commands; mode transitions logged with timestamped audit trail per FDA 21 CFR Part 11 Annex 11 requirements.
• Integrated instrumentation: Flip-type level indicator with visual/audible high/low alarms and isolated 4–20 mA analog output for remote HMI monitoring; optional corrosion-resistant wetted materials (316L SS, PTFE diaphragms, EPDM seals) compliant with ASTM A240 and NACE MR0175.
• Electrical protection suite: Thermal overload relays, phase-loss detection, short-circuit interrupters, and ground-fault circuit interrupters (GFCI) conforming to IEC 60204-1 and UL 508A standards.

Sample Compatibility & Compliance

The HK-5300 system accommodates aqueous solutions of sodium tripolyphosphate (STPP), hydrazine hydrate, carbohydrazide, morpholine, cyclohexylamine, and polyacrylic acid-based scale inhibitors—subject to material compatibility verification per NACE TM0177 and ASTM D1384 corrosion testing protocols. All fluid-contact components meet USP Class VI biocompatibility criteria where required for pharmaceutical-grade steam generation. The control cabinet complies with electromagnetic compatibility (EMC) per EN 61000-6-2/6-4 and carries CE marking for machinery directive 2006/42/EC. For nuclear or marine applications, optional ASME Section III, Div. 1 qualified pressure parts and ABS-certified structural mounting frames are available upon specification.

Software & Data Management

The embedded industrial PC runs a deterministic real-time OS with deterministic loop execution (≤100 ms scan time) and stores ≥30 days of compressed process data locally (tagged timestamps, setpoints, actual values, alarm states, pump status). Data export supports CSV, OPC UA, and secure FTP protocols. Audit trails include user login/logout events, parameter modifications, and mode changes—with SHA-256 hashing and write-once storage to prevent tampering. Optional cloud gateway enables encrypted TLS 1.3 telemetry to enterprise MES platforms (e.g., Siemens Opcenter, Rockwell FactoryTalk) while preserving on-premise data sovereignty.

Applications

• Thermal power plants: Coordinated phosphate-hydrazine treatment for drum-type boilers (ASME B31.1 piping code compliance).
• Combined-cycle gas turbine (CCGT) facilities: Ammonia dosing in condensate return lines to maintain pH >9.2 at 25°C per EPRI TR-102527.
• Chemical manufacturing sites: Continuous inhibitor injection into recirculating cooling towers per CTI STD-201 guidelines.
• Fertilizer production units: Precise ammonium hydroxide dosing in high-purity deionized water loops for catalyst protection.
• Steel mill desalination plants: Polymeric dispersant delivery to reverse osmosis pretreatment stages.

FAQ

What communication protocols does the HK-5300 support for DCS integration?

Modbus RTU (RS-485), Modbus TCP (Ethernet), and Profibus DP (with optional gateway module); all configurable via web-based engineering interface.

Can the system operate without external analyzer signals?

Yes—manual and soft-manual modes allow fixed-rate dosing; however, automatic closed-loop control requires live 4–20 mA or HART inputs from compatible online analyzers.

Is the solution tank equipped with level measurement redundancy?

Standard configuration includes a mechanical flip-level gauge with dry-contact alarm outputs; optional ultrasonic or guided-wave radar transmitters (SIL 2 certified) are available for critical applications.

How is pump calibration traceability maintained?

Each metering pump is supplied with a factory calibration certificate (ISO/IEC 17025 accredited lab), and on-site verification can be performed using gravimetric or volumetric methods per ASTM D1193.

Does the system meet cybersecurity requirements for modern OT networks?

Yes—the embedded controller supports role-based access control (RBAC), firmware signature validation, disabled default credentials, and network segmentation via VLAN tagging per IEC 62443-3-3 SL2 recommendations.