The working principle of the explosion-proof air shower room can be summarized as follows: high-speed clean air flow circulation for dust removal + full-loop explosion-proof electrical and anti-static design + double-door interlocked air lock isolation. It simultaneously achieves personnel purification and inherent safety in flammable and explosive environments. 1. Basic purification principle (the same as ordinary air shower room) Induction and interlock: When personnel enter the air shower room, the explosion-proof infrared sensor detects the position, and the dual-door electronic interlock is activated. The two doors cannot be opened simultaneously, forming an air lock isolation. Air circulation: The explosion-proof centrifugal fan sucks in the indoor air, passing through G4 primary filter (intercepting particles larger than 5 μm) → static pressure box for pressure stabilization → H13/H14 high-efficiency filters (filtering particles of 0.3 μm with an efficiency of ≥ 99.97%). High-speed blowing: Clean air is blown through the multi-angle adjustable nozzles on both sides and the top of the box at a speed of 25–35 m/s, forming a 360° no-corner blowing, removing dust, fibers, and microorganisms from the surface of clothing. Return air filtration: The contaminated air flows back through the bottom return grille and enters the primary / high-efficiency filters

Select explosion-proof air shower cabinets, the core is to first determine the explosion-proof level → then match the purification and size → finally check the material, electrical and certification. Five steps can lock in the compatible model, avoiding both safety and purification risks. 1. First, clearly define the hazardous environment (the explosion-proof level is the lifeline) 1) Hazard zone classification (GB 3836/GB 50058) Zone 0: Continuous presence of flammable gas (rarely used, requires Ex ia intrinsically safe type) Zone 1: May occur during normal operation (mainstream: Ex d IIB T4 flameproof type) Zone 2: Only briefly present during abnormal conditions (optional: Ex d IIB T4 or Ex ec enhanced safety type) 2) Temperature group (T4 is the most commonly used) T4 (≤135℃): Lithium batteries, chemicals, pharmaceuticals (suitable for most solvents / dust) T6 (≤85℃): Highly flammable media (such as ether, ethylene oxide) 3) Typical industry configuration reference Lithium battery workshop (aluminum powder / electrolyte vapor): Ex d IIB T4, 304 stainless steel, anti-static Chemical / pharmaceutical (organic solvents): Ex d IIB T4, 316 stainless steel, corrosion-resistant Spraying / ink (paint mist / solvent): Ex d IIB T4, anti-static nozzle, spark-free fan 2. Match purification level and air shower performance 1)

The complete working principle of explosion-proof FFU (easy-to-understand + professional version) I. Overall Definition Explosion-proof FFU = Explosion-proof sealed motor + centrifugal fan + efficient filter + explosion-proof electrical sealing structure that combines local air circulation purification + explosion-proof flame retardancy and elimination of ignition sources as the two core functions. II. Basic purification working principle (consistent with ordinary FFU) Negative pressure intake The fan rotates at high speed, sucking in the workshop air from the top; Positive pressure supply The centrifugal fan generates static pressure, evenly pushing the air downward; Efficient filtration The airflow passes through HEPA/ULPA efficient filters, filtering dust and particles; Laminar air supply The clean air is sent downward in a uniform laminar flow, maintaining the pressure difference and cleanliness of the clean room / explosion-proof clean area. III. Core: Explosion-proof principle (key difference) This is the core part of explosion-proof FFU, used to prevent flammable and explosive gases, solvent vapors, and combustible dust from being ignited. 1. Motor explosion-proof isolation A flameproof / enhanced safety type explosion-proof motor is used, with the motor stator, coil, and wiring chamber being fully enclosed explosion-proof cavities; Even if there is a short circuit, sparking, or generation of electric

Explosion-proof FFU standard maintenance cycle (industry standard + lithium battery / chemical / pharmaceutical explosion-proof scenarios) Based on explosion-proof regulations + cleanroom operation + annual explosion-proof electrical inspection requirements, the cycle is clearly defined in four major items and directly implemented. 1. Daily inspection (daily) Check for abnormal sounds, vibrations, excessive heat, and odors Check for any loosening or cracking of explosion-proof junction boxes, shells, and seals Check the grounding of the machine body and the integrity of the equipotential connection lines Applicable: All explosion-proof FFUs, mandatory 2. Routine maintenance (monthly) Clean the FFU body and floating dust in the intake ports Tighten explosion-proof screws, connection terminals, and explosion-proof sealing joints of cables Check the pressure difference of the filter, and the uniformity of the air outlet Check the temperature rise of the motor and whether the operating current is normal 3. Mid-term maintenance (every 3 to 6 months) 1. Filter replacement General explosion-proof clean areas: about 6 months Lithium battery / chemical / high solvent, high dust environment: about 3 months Based on the pressure difference value: replace immediately if the resistance exceeds the standard (prioritize checking the pressure difference, not strictly adhering to the time limit) 2. Fan

Explosion-proof FFU Installation + Maintenance Complete Set of Precautions (Industry Practical Version) I. Installation Precautions 1. Preliminary Selection and Environmental Matching Select according to the actual explosion-proof area level (Ex d IIB/IIC T4/T6, gas / dust explosion-proof classification), and strictly prohibit using ordinary FFU to replace explosion-proof units. Confirm the temperature and humidity, corrosive gases, and concentration of flammable and explosive vapors on site, and match with anti-corrosion and anti-static models. Verify the load-bearing capacity of the clean room ceiling, as the explosion-proof FFU is heavier, the brackets and ceiling frame must be reinforced. 2. Electrical Installation (Explosion-proof Core) Use explosion-proof conduit, explosion-proof junction boxes, and sealed joints for electrical wiring. Ensure the sealing of interface fillers is compact to prevent combustible gas from entering the cavity. Must perform reliable grounding and equip potential equalization connections. Connect the entire machine, frame, and metal parts of the ceiling to eliminate static accumulation. Do not privately modify or connect power lines; the wiring must be firmly pressed to prevent short circuits and sparking; switches and controllers must be of explosion-proof type. Use explosion-proof frequency converters / explosion-proof control modules for variable frequency control. Ordinary speed regulators are prohibited from use in explosion-proof

Explosion-proof FFU (Explosion-proof Fan Filter Unit) is mainly used in places where there is a risk of fire and explosion and where high cleanliness standards are required. Its core lies in simultaneously meeting the two demands of “explosion-proof safety” and “air purification”. I. Electronics / Semiconductor and Display Industry Semiconductor manufacturing: Chip fabrication, lithography / etching workshops, wafer clean rooms (organic solvents / silane flammable). Optoelectronic display: LCD/OLED panels, backlight modules, optical lens workshops (ink / solvent evaporation). Precision electronics: Hard drives / magnetic heads, micro-motors, sensor assembly (anti-static + explosion-proof). II. New Energy and Battery Industry Lithium battery manufacturing: Cathode and anode coating, injection, formation workshops (electrolyte vapor flammable). Energy storage / hydrogen: Energy storage stations, fuel cell workshops, hydrogen production area (hydrogen explosion-proof). III. Medicine and Biochemical Engineering Pharmaceutical workshops: Sterile raw materials, organic solvent crystallization / drying areas, explosion-proof clean sheds (ethanol / acetone etc.). Biological preparations: Fermentation tank areas, sterile sampling, biosafety laboratories (BSL-3/4). Fine chemicals: Explosion-proof clean reaction areas, powder feeding / mixing (combustible dust). IV. Food / Cosmetics and Powder Industry Food processing: Milk powder / cocoa powder production, sterile filling lines (starch / milk powder dust explosion-proof). Cosmetics: Perfume / perfume formulation, powder

The core difference between a negative pressure weighing chamber and a laminar flow hood lies in the pressure direction, protection goals, air flow organization, and application scenarios: A negative pressure weighing chamber is a negative pressure isolation, focusing on preventing the escape of dust / harmful substances and protecting personnel and the environment; a laminar flow hood is a positive pressure laminar flow, focusing on preventing external pollution intrusion and protecting product cleanliness. I. Core Principle and Pressure State Negative Pressure Weighing Chamber (Negative Pressure Weighing Hood) Pressure: The internal pressure is relatively lower than the external pressure (-10 to -30 Pa), with air flowing from the outside into the chamber and not escaping inside. Air Flow: Vertical single-direction laminar flow, with some circulation and some filtered before being discharged externally, to prevent the diffusion of dust / aerosols. Protection: Protecting personnel and the external environment, preventing the escape of material dust, active pharmaceuticals, and harmful reagents, and preventing cross-contamination. Laminar flow hood (clean laminar flow cabinet) Pressure: Internal is slightly positive pressure relative to the outside, clean air flows “blowing out” from the inside to prevent external contamination from entering. Air flow: Vertical / Horizontal unidirectional laminar flow (ISO

Conclusion: Under normal maintenance, the negative pressure weighing chamber typically lasts for 8–12 years, and the laminar flow hood typically lasts for 10–15 years; the core components (fans, electrical control, HEPA) have a shorter lifespan and need to be replaced in the middle stage. I. Negative Pressure Weighing Chamber (Whole Machine) Design Life: 8–12 years (industry standard) Good Maintenance: Up to 10–15 years (304 stainless steel, properly sealed, regular verification) Harsh Conditions / Minimal Maintenance: 5–8 years (highly active dust, acid-base corrosion, air leakage, not replacing filter materials in time) Core Component Lifespan Fan (supply + exhaust): 5–8 years (approximately 60,000 hours) Control System (PLC, differential pressure sensor): 6–8 years Supply HEPA: 1–2 years; Exhaust HEPA: 0.5–1 year (high dust load) Sealing / Soft Curtains: 0.5–1 year (frequent replacement) II. Laminar Flow Hood (Whole Machine) Design Life: 10–15 years (simple structure, positive pressure, low dust) Good Maintenance: Up to 15–20 years (stainless steel / zinc-aluminum plate coating, only replace HEPA, clean environment) Minimal Maintenance / High Humidity: 8–10 years (line aging, box rusting, uneven wind speed) Core Component Lifespan Fan: 8–10 years (6–10,000 hours, single fan, low load) Control System: 8–12 years (simple speed regulation, no negative pressure interlock) Supply

1. Environmental conditions for use Temperature and humidity: High humidity and frequent washing environment, prefer 304 stainless steel; dry and regular environment can choose aluminum alloy. Corrosion: Presence of acid and alkali gases, organic solvents, frequent ozone / peracetic acid disinfection, do not use ordinary carbon steel, choose 304 stainless steel. Dust and cleanliness level: High cleanliness level requires smooth surface, no dust accumulation, easy to wipe, avoid rough and easily dusty ordinary steel. 2. Industry compliance requirements Pharmaceuticals, medical devices, food, biological laboratories: Must comply with GMP, require corrosion resistance, water washability, no precipitation, easy cleaning, prefer 304 stainless steel. Electronics, semiconductors, optoelectronics: No special compliance requirements, focus on cost performance, choose aluminum alloy. 3. Service life and durability Long-term fixed use (more than 8 years): Aluminum alloy, 304 stainless steel. Temporary transition, short-term use (3–5 years): Can choose galvanized square steel, powder-coated carbon steel, control costs. 4. Structural load-bearing and stability Large shed area, many FFU, need to install lamps / pipelines: Select stronger thickened aluminum alloy or stainless steel to avoid frame deformation. Small and simple clean shed: Ordinary standard aluminum profiles can meet requirements. 5. Budget cost Cost ranking: Powder-coated carbon steel < Aluminum alloy <

I. Unique Identification and Traceability (One Item, One Code; One Machine, One Number) Each air supply ceiling unit is assigned a unique equipment number, installation area, and cleanliness level. These details are fixed in the record header and are not reused or misnumbered. All records, filter ledgers, pressure difference data, and maintenance records are bound to the same equipment number, allowing for the retrieval of the full cycle archives by the equipment number at any time. Filters, fans, seals and other components are individually numbered and linked to maintenance records, enabling traceability of the replacement batch, supplier, and installation time. II. Time Chain Traceability (No Interruption, No Skipping Periods) Records are meticulously kept according to daily inspections, weekly maintenance, monthly pressure difference checks, and quarterly leak detection cycles. The dates are consecutive, without gaps or skipped days. During production, downtime, and holidays, reasons must be noted in text form. Blank dates are not allowed. Ensure the time chain is complete and traceable. Each record must precisely fill in the year / month / day / hour and minute to avoid only writing the date without the specific time. III. Personnel Traceability (Responsibility Assigned to Individuals) The principle of “who operates,

The automatic air shower room, as the core purification buffer equipment in a clean environment, mainly functions to remove dust, hair, dander, microorganisms and other contaminants on the surfaces of personnel and materials, and to prevent non-clean air from invading the clean area. It is suitable for various industries and scenarios with strict standards for environmental cleanliness, hygiene safety and production accuracy. The specific application fields and sub-scenarios, as well as the core adaptation requirements are as follows: 1. Pharmaceutical and medical device industry (core essential field) This industry has the top standards for cleanliness and sterility. The automatic air shower room is a necessary supporting equipment for GMP certification and sterile production. It is mainly applied in chemical pharmaceutical workshops, biological pharmaceutical workshops, vaccine research and production workshops, sterile injection production lines, hospital sterile operating rooms, medical device workshops (including disposable consumables, implantable devices), biological safety laboratories, etc. Its core function is to purify the personnel, laboratory personnel and small medical materials entering the clean area, prevent dust, bacteria and microorganisms from contaminating, ensure the quality of drugs, experimental safety and the sterility of medical devices, avoid cross-infection and production compliance risks. 2. Electronics and semiconductor new energy industry

I. Working Principle The negative pressure weighing chamber is a type of local purification and negative pressure isolation equipment. The core lies in the use of vertical unidirectional flow and stable negative pressure to prevent dust from spilling out and protect personnel and the environment, meeting the protection requirements of GMP for the weighing of highly active/toxic materials. 1. Airflow organization (vertical unidirectional flow) Three-stage filtration: Return air first passes through the primary filter (for large particles) → the intermediate filter (pre-filter, protecting HEPA) → the high-efficiency HEPA (with a 0.3μm retention rate ≥ 99.99%). Air flow distribution: The fan sends the clean air into the static pressure box, 90% of which is vertically downward (forming a class 100 / ISO5 clean area), 10% of which is a small amount of exhaust air, maintaining a relative negative pressure of -5 to -15 Pa in the operation area. Negative pressure isolation: Air only enters and does not exit. Dust is filtered by the airflow and does not escape, avoiding cross-contamination and occupational exposure. 2. Core structure Box: 304 stainless steel, seamless welding, corrosion-resistant, easy to clean. Filter system: Primary G4, intermediate F8, high-efficiency H14/ULPA. Fan + static pressure box: Provide stable