Different from ordinary clean‑room equipment, the negative‑pressure weighing booth adopts a unique airflow design: air supply from top and air suction from bottom, clean airflow toward the working zone and negative‑pressure toward external environment. The two systems operate independently yet cooperate with each other to realize bidirectional protection.
The upper section is the vertical laminar air‑supply system. After three‑stage filtration by G4 pre‑filter, F8 medium‑efficiency filter and H14 HEPA filter, air forms ISO Class 5 (Class 100) vertical laminar flow covering the weighing working area. It isolates dust and microorganisms from outside the booth to prevent the powder materials from external contamination, so as to guarantee material purity and product quality.
The lower section and surrounding areas constitute the negative‑pressure dust‑collection and pollution‑control system. A stable slight negative‑pressure of 5‑10 Pa is maintained inside the unit, building an inward airflow pressure gradient. Fine dust particles generated during powder weighing and feeding are rapidly drawn into the exhaust filtration system by negative‑pressure airflow, thoroughly preventing dust from escaping and spreading into the clean workshop. This mechanism fundamentally solves common problems of traditional open‑mode operation such as dust dispersion, workshop pollution and cross‑contamination between different materials.
Coordination logic of dual‑systems: Laminar air supply guarantees material cleanliness, while negative‑pressure suction restrains dust diffusion. The supply‑and‑suction combination forms a stable closed‑loop airflow. It not only protects materials against contamination, but also keeps the workshop free of dust pollution, meanwhile prevents operators from inhaling powder dust. Triple objectives are achieved: material safety, environmental cleanliness and personnel protection.
The whole system delivers stable airflow without eddies or dead corners, with efficient dust interception. It fully satisfies mandatory GMP requirements on cross‑contamination prevention and dust control for powder‑handling processes, and serves as essential compliant equipment for powder‑related operations in pharmaceutical, chemical and food industries.
