Weighing hood controller: The core of intelligent control for powder weighing in GMP cleanroom environments.
I. Industry Demand-Driven: Why is a Weighing Hood Controller Indispensable?
The unique nature of powder weighing dictates high requirements for control equipment. On one hand, the weighing of materials such as raw pharmaceutical materials and vaccine raw materials needs to be carried out in a strictly negative pressure environment to prevent dust from escaping and contaminating the workshop environment or harming the health of operators. On the other hand, the production process must meet the rigid requirements of GMP for data traceability, cleanliness maintenance, and cross-contamination prevention. Traditional manual control methods not only struggle to achieve precise and stable negative pressure and airflow, but also cannot meet the needs of automated recording and coordinated control. The emergence of the weighing hood controller precisely fills this technological gap. By integrating intelligent control modules, sensing and detection units, and coordinated execution components, it achieves integrated control of key aspects such as negative pressure, airflow, sterilization, and dust removal. This ensures the cleanliness and safety of the weighing process and provides reliable support for production compliance, making it an essential core component of modern clean production workshops.
II. Core Function Analysis: Precise Control of Every Key Aspect The value of the weighing hood controller lies in its customized functional design for powder weighing scenarios, enabling intelligent management throughout the entire process, from environmental control to safety protection.
1. Precise Steady-State Control of Negative Pressure and Air Velocity This is the core function of the weighing hood controller. Through variable frequency speed control technology, the controller can precisely adjust the speed of the supply and exhaust fans, stabilizing the negative pressure inside the hood within the GMP standard range of -5 to -20 Pa, fundamentally preventing powder dust from escaping. Simultaneously, based on the weighing requirements of different materials, it can achieve stepless adjustment of airflow speed from 0.3 to 0.5 m/s, forming a stable vertical or horizontal airflow barrier, preventing external pollutants from entering the weighing area and avoiding cross-contamination of materials. Whether manually adjusting the airflow speed or automatically adjusting it dynamically according to dust concentration and hood status, it ensures the stability and adaptability of environmental parameters.
2. Multi-dimensional Monitoring and Intelligent Alarms To ensure the traceability and safety of the production process, the weighing hood controller integrates comprehensive status monitoring and alarm functions. By connecting to components such as differential pressure sensors, wind speed sensors, and dust concentration sensors, it collects key data in real time, including filter differential pressure, negative pressure inside the hood, fan operating current, and dust concentration, and displays them intuitively on the touchscreen. When situations such as excessive filter differential pressure (indicating the need to replace the filter), negative pressure deviating from the set range, fan overload, or abnormal dust concentration occur, the controller will immediately trigger an audible and visual alarm and record the fault code and occurrence time, facilitating quick troubleshooting by operators and avoiding production risks caused by equipment failure. The intelligent controller also supports data storage and export functions, allowing data such as operating parameters and alarm records to be exported to Excel format via USB flash drive, fully meeting the stringent GMP requirements for production process data traceability.
3. Full-Process Automated Linkage Control The intelligent advantages of the weighing hood controller are further reflected in its powerful linkage control capabilities, realizing automated coordination of processes such as weighing, sterilization, and dust removal. In the sterilization process, the UV lamp's delayed start and stop programs can be preset. For example, the UV lamp can automatically turn on for 30 minutes before weighing, and automatically switch to working mode after sterilization, requiring no manual intervention. In the dust removal process, the matching dust removal device can be automatically activated during weighing to adsorb loose powder particles in real time, keeping the inside of the hood clean. Regarding door control, when the weighing hood's protective door is opened, the controller automatically increases the fan speed to enhance negative pressure and airflow barrier; after the door is closed, the fan speed drops back to energy-saving mode, balancing cleanliness and energy consumption control. Furthermore, high-end controller models support industrial communication protocols such as Modbus and Profinet, allowing seamless integration with the workshop's central control system or MES system. This enables centralized management of multiple weighing hoods, unified parameter settings, and real-time data upload, significantly improving production management efficiency.
4. Safety and Energy-Saving Design
Regarding safety, the weighing hood controller incorporates multiple electrical protections, including overload, undervoltage, and short-circuit protection, effectively preventing fan damage due to abnormal operating conditions. For UV lamp usage scenarios, a human body induction interlock device is provided; when personnel approach the weighing hood, the UV lamp automatically shuts off to prevent UV burns and ensure operator safety. It also features a power-off memory function, automatically restoring previous operating parameters after a power outage and restart, eliminating the need for resetting and ensuring production continuity.
Energy efficiency is another key highlight. Adopting a variable frequency speed control design, compared to traditional fixed-speed control, the fan speed can be dynamically adjusted according to actual production needs, avoiding ineffective energy consumption. The overall energy saving rate can reach over 30%, significantly reducing enterprise production and operating costs in the long term.