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The production environment for semiconductor devices is extremely sensitive to the presence of contaminants. Even small amounts of gaseous or particulate contaminants can reduce product quality. Therefore, cleanliness requirements in semiconductor device manufacturing are far higher than in other industries.     Throughout the entire chip and semiconductor device manufacturing process, process environment contamination control is crucial. The air cleanliness of core processes needs to meet ISO Class 1 standards, with gaseous molecular contaminant (AMC) concentrations below one part per billion. Substandard process environments can lead to a significant reduction in product yield.   Ordinary air contains a large number of particulate contaminants such as microparticles and dust, as well as gaseous contaminants such as sulfur dioxide, nitrogen oxides, and ammoniaaa. Only after treatment can it enter a cleanroom. Because cleanrooms used for producing semiconductors and other microelectronic devices must maintain standard cleanliness levels 24/7, the cleanroom air conditioning system (including the exhaust system), its associated heat and cold sources, and corresponding delivery systems must operate 24 hours a day, which is significantly different from other conventional air conditioning systems.   As the power source, the fan consumes most of its energy due to the combined resistance of its components. Furthermore, the air filter's resistance accounts for approximately 50% of the fan's total head. Therefore, reducing the energy consumption of air conditioning filters is crucial for lowering building energy consumption and carbon emissions. From the perspective of improving energy efficiency and reducing energy consumption, optimizing air filter performance without compromising filtration requirements is essential.     Filter energy consumption is directly determined by average resistance and is related to initial resistance and dust holding capacity. Reducing initial resistance, increasing dust holding capacity, and minimizing the increase in resistance during dust holding are effective ways to reduce energy consumption, thus lowering energy costs for customers and contributing to environmental protection.

Air filters are filtration-based air purifiers. The HEPA filter we often hear about stands for High-efficiency Particulate Air Filter.   Let's break down the five core principles of air filtration to help you understand its underlying logic.     1. Interception Effect: The fibers in a filter are intricately arranged. When airborne dust particles come into contact with the surface of the filter fibers, they are directly trapped if the particle is close enough to the filter material. This phenomenon is particularly evident in dense filter materials, such as the three-dimensional mesh structure formed by ultra-fine fibers in meltblown fabric for masks, which can firmly lock viral aerosols within the fiber gaps.   2. Inertial Effect: The complex arrangement of filter fibers in an air filter causes airflow to encounter obstacles and deflect as it passes through the filter material. Dust particles in the air, under the influence of inertial forces, break away from the streamline and collide with the surface of the filter fibers, depositing there. The larger the particle, the greater the inertial force, the greater the likelihood of it being blocked by the filter fibers, and the better the filtration efficiency.   3. Diffusion Effect: The diffusion effect targets ultrafine particles smaller than 0.1 micrometers. Particles smaller than 0.1 micrometers primarily undergo Brownian motion, exhibiting a disordered trajectory, significantly increasing the probability of contact with filter fibers; the smaller the particle, the easier it is to remove.   4. Gravity Effect: When the airflow velocity is lower than the particle settling velocity, larger particles naturally settle under gravity. Flue gas treatment towers in thermal power plants expand the space and reduce the flow velocity, allowing dust to fall into the dust collection hopper like sand settling to the bottom of water. This mechanism is economical and efficient for treating high concentrations of dust, but its effect on suspended particles is limited, and it is usually used as a pretreatment method.   5. Electrostatic Effect: Electrostatic electret technology charges the fibers, giving the filter material the ability to actively capture particles with opposite charges, much like a magnet attracts iron filings. This mechanism is particularly effective for charged particles in PM2.5, and industrial dust removal equipment performs electret treatment on the filter surface.

Cleanrooms place stringent requirements on ventilation systems. They must provide sufficient airflow and pressure while precisely controlling temperature and humidity, ensuring consistent air quality. These requirements apply to various airflow patterns and room sizes.   Many production processes mandate cleanroom conditions because cleanrooms, and even ultra-cleanrooms, guarantee the environmental quality of products during rigorous manufacturing. Even minute impurities in the air can adversely affect production processes, leading to high scrap rates. For example, production environments in fields such as optics and lasers, aerospace, biosciences, medical research and treatment, food and pharmaceutical production, and nanotechnology require a near 100% dust-free and bacteria-free air supply.   However, air conditioning and ventilation systems in cleanrooms consume significant amounts of energy due to high air exchange rates, making energy efficiency and cost critical issues. Therefore, in addition to meeting aerodynamic performance requirements, fans must also meet key standards such as compact size, low noise, use cleanroom-compatible materials, proper control capabilities, networking capabilities, and energy-efficient operation.   FFU are designed specifically to address these needs. They effectively improve ventilation in cleanrooms, ensuring the stability of the production environment and product quality.     An FFU is a device that cleverly combines a filtration system with a fan. It features a ceiling-mounted design, is compact and efficient, and requires minimal installation space. The FFU contains pre-filters and high-efficiency filters. Air is drawn in from the top by the fan, finely filtered, and then uniformly delivered at a velocity of 0.45 m/s ± 20%.   FFU play a crucial role in cleanrooms, clean benches, clean production lines, modular cleanrooms, and localized Class 100 environments. These applications span semiconductor, electronics, flat panel display, and disk drive manufacturing, as well as optics, biomedicine, and precision manufacturing—industries with stringent requirements for air pollution control.   The flexibility and ease of use of FFU: The self-powered, modular design of the FFU makes replacement, installation, and relocation simple and easy. Its matching filters are easy to replace, not limited by location, and ideal for the zoned control needs of cleanrooms. FFU can be easily replaced or moved to adapt to different clean environments as needed. Furthermore, FFU can be used to easily create simple clean benches, clean booths, clean pass-through cabinets, and clean storage cabinets to meet various cleanliness requirements. Its ceiling-mounted installation method, especially in large cleanrooms, significantly reduces construction costs.   Negative Pressure Ventilation Technology: The unique negative pressure ventilation design of the FFU fan filter unit allows it to easily achieve high-level cleanliness in various environments. Its self-powered characteristic maintains positive pressure inside the cleanroom, effectively preventing the infiltration of external particles and ensuring a safe and convenient seal.   Quiet Operation: The FFU fan filter unit boasts excellent quiet operation, maintaining low noise even during prolonged use. Its vibration is very low, ensuring smooth stepless speed regulation and uniform airflow distribution, providing stable support for the clean environment.    Cleanroom Air Supply Units    * Rapid Construction: Utilizing FFU technology, there is no need for ductwork fabrication and installation, significantly shortening the construction cycle.   * Reduced Operating Costs: Supplying clean air to cleanrooms with FFU technology is not only economical but also remarkably energy-efficient. Although the initial investment for FFU may be slightly higher than ducted ventilation, their maintenance-free operation over the long term significantly reduces overall operating costs.   * Space Saving: Compared to other systems, FFU systems occupy less floor height within the plenum chamber and take up virtually no space within the cleanroom.   * Wide Applicability: FFU systems can adapt to cleanrooms and microenvironments of varying sizes and cleanliness requirements, providing high-quality clean air. During the construction or renovation of cleanrooms, it not only improves cleanliness but also effectively reduces noise and vibration.   FFU System Applications in Semiconductor Wafer Shops: FFU systems are widely used in cleanrooms requiring ISO 1-4 air purification levels, playing a crucial role, particularly in the vertical laminar flow operations of semiconductor wafer shops. In the technical mezzanine, air is efficiently delivered to the clean production layer via FFU. This airflow then passes through raised floors and waffle slab openings, reaching the clean lower technical mezzanine. Finally, after being processed by DCC (Dry Cooling Coils) in the return air duct, the air returns to the upper technical mezzanine, forming a cycle. This design effectively supports the wafer fabrication workshop's stringent control over the production environment, including temperature, humidity, cleanliness, and vibration damping.   Furthermore, the application of FFU systems in biological laboratories is also significant. When laboratory personnel handle pathogenic microorganisms, experimental materials containing pathogenic microorganisms, or parasites, FFU systems impose special requirements on laboratory design and construction to ensure experimental safety and a pollution-free environment.   Current laboratory purification systems typically consist of multiple parts, including a static pressure layer, a process layer, a process auxiliary layer, and a return air duct. This system primarily relies on FFU to process the air. Its working principle is: the FFU provide the necessary circulation power, mixing fresh air with recirculated air, which is then delivered to the process layer and process auxiliary layer after passing through ultra-high efficiency filters. At the same time, by maintaining a negative pressure state between the static pressure layer and the process layer, the leakage of harmful substances is effectively prevented, ensuring the cleanliness and safety of the laboratory environment.

The breakthrough in rubber tree tissue culture technology is accelerating the upgrading of modern agriculture. The innovative technology from the Rubber Research Institute of the Chinese Academy of Tropical Agricultural Sciences, through somatic embryogenesis and cutting propagation, has achieved efficient propagation and quality improvement of rubber seedlings, injecting new vitality into the plant tissue culture industry.   However, plant tissue culture requires extremely high demands on the growth environment, necessitating highly clean laboratory conditions to ensure sterile growth. Traditional air purification equipment often fails to meet the stringent requirements for particle and microbial control, leading to increased contamination risks and affecting the survival rate and quality of tissue-cultured seedlings.     Therefore, the upgrading of air purification equipment has become crucial for the development of tissue culture technology.   With 20 years of accumulated experience in air purification technology, KLC, with its innovative technology and professional design, provides comprehensive clean environment support for rubber tree tissue culture technology. Together, they have built an efficient, intelligent, and easy-to-maintain air purification system, providing strong protection for the growth environment of plant tissue culture.      Wide-Area Purification, Ensuring Sterile Growth  KLC's HEPA air filters, with their excellent filtration performance, ensure that the air cleanliness of the tissue culture laboratory reaches ultra-high efficiency standards. Its high-efficiency filtration performance ensures that tissue-cultured seedlings grow under sterile conditions, reducing the risk of contamination. Continuous air purification covers the entire space, achieving seamless purification and providing stable support for all areas of the tissue culture laboratory, ensuring pollution-free operation throughout the tissue culture process and guaranteeing the continuous and stable operation of a large clean area.      Air Shower Protection, Blocking Contamination Invasion  KLC air shower pass-through windows are used for material transfer, ensuring that materials are air-showered before entering the laboratory to remove surface contaminants. This effectively prevents external contaminants from entering the laboratory through materials, protecting the growth environment of tissue-cultured seedlings.      Horizontal Cleanliness, Protecting Sterile Operations  Some plant tissue culture processes require highly clean bench to ensure sterility. KLC horizontal laminar flow bench provide a horizontal clean airflow, ensuring the air cleanliness of the work area. This provides a sterile working environment for operations such as inoculation and cultivation of rubber tree tissue-cultured seedlings.      Laminar Flow Coverage, Precisely Guaranteeing Sterile Space  Plant tissue culture requires extremely high cleanliness in localized operating areas, especially in some high-precision experimental operations. KLC laminar flow hoods, through their precise laminar flow design, provide a highly clean air environment for specific areas. Their vertical or horizontal laminar airflow patterns effectively remove contaminants from localized areas, ensuring sterile conditions in critical operating zones. Whether for inoculation, cultivation, or other sensitive operations, KLC laminar flow hoods provide precise cleanliness assurance for tissue culture growth, facilitating the smooth progress of experimental procedures.     KLC's air purification solutions provide high-quality clean air for plant tissue culture technology and offer strong support for the development of modern agricultural technology. KLC is committed to providing customized air purification solutions for tissue culture laboratories, research institutions, and agricultural enterprises, helping to advance tissue culture technology.

The core functions and detailed differences between air shower and pass box in cleanrooms: The core commonality of both is to control contamination and maintain the cleanroom environment level. Both must comply with regulations and standards such as GMP and ISO 14644. However, there are significant differences in their applicable objects, working principles, and operating requirements, as detailed below:      I. Similarities  1. Structural Anti-Cross-Contamination Both are equipped with a double-door interlocking device, preventing both doors from opening simultaneously. This physically blocks the direct airflow between the cleanroom and non-cleanroom (or different levels of cleanrooms), preventing cleanroom pressure imbalance and pollutant diffusion.     2. Consistent Regulations and Management Requirements Both must be included in the cleanroom equipment management system, with complete maintenance and calibration records, and subject to regular audits and inspections.Daily cleaning requires the use of lint-free cleanroom wipes to wipe the inner walls, and no miscellaneous items are allowed to be stored inside the equipment to prevent them from becoming new sources of contamination.   3. Similar Maintenance and Calibration Principles Both require regular inspection of the door seal integrity and the operating status of functional components, and timely replacement of aging consumables (such as filters and UV lamps) to ensure that the equipment is always in a compliant operating state.    II. Differences  1. Applicable Objects Air shower are applicable to personnel and large material carriers, such as operators and inspectors entering the cleanroom, as well as stainless steel trolleys and large turnover boxes carrying materials. They can meet the needs of large and bulk material carriers. Pass box are only suitable for small materials, tools, and documents, such as sample bottles, reagent tubes, cleanroom wipes, sterile gloves, and clean versions of batch production records. Personnel or large items are strictly prohibited from passing through.   2. Core Purification Principles The air shower chamber uses high-speed airflow blowing and filtration as its core principle.A fan blows air, filtered by a high-efficiency particulate air (HEPA) filter, through nozzles at a speed of no less than 25 m/s, forcibly removing dust particles and microorganisms attached to personnel clothing fibers and trolley surfaces. The blown-off contaminants are collected through the return air vents and filtered again, forming a circulating purification process. The pass box uses physical isolation and auxiliary disinfection as its core principle. The basic model only achieves spatial isolation through interlocking doors and has no active purification function; models with UV disinfection have a built-in 253.7nm wavelength UV lamp, which, when activated, irradiates for 15-30 minutes, killing bacteria by destroying the DNA structure of microorganisms.There is no airflow blowing function throughout the process, so it does not change the attachment state of particles on the surface of objects.   3. Installation Location and Environmental Requirements The air shower chamber should be installed in the buffer zone at the main entrance for personnel/materials in the clean area, forming a three-level separation between the non-clean area and the clean area (non-clean area → air shower chamber → clean area). The installation area needs to have sufficient space for passage to ensure that the doors can be fully opened. It also needs to be linked to the pressure difference of the clean area; the pressure difference inside the air shower chamber should be slightly lower than the clean area and higher than the non-clean area. The pass box is directly embedded in the partition wall between the clean area and the non-clean area, or between different levels of clean areas. The installation location should be convenient for personnel on both sides to operate. The wall opening size needs to match the specifications of the pass box. No additional pressure difference control is required; it only needs to ensure consistency with the environmental parameters of the surrounding area.   4. Operating Procedure The operating procedure of the air shower chamber is as follows: After personnel or a trolley enters, the outer door closes, and the interlocking device locks the inner door; the infrared sensor triggers the fan to blow air, with a preset blowing time of 15-30 seconds (adjustable according to the cleanroom class); after the blowing is completed, the fan stops, the inner door unlocks, and personnel or the trolley can enter the clean area. Forcibly opening the interlocking doors is prohibited throughout the process. The emergency stop button should only be used in emergency situations. The pass box operates as follows: personnel on the non-clean side open the outer door, place the items inside, and close the outer door to ensure the interlock is activated; if it is a model with UV disinfection, the UV lamp must be turned on and remain on for the set disinfection time before being turned off; personnel on the clean side confirm that the outer door is closed, then open the inner door to retrieve the items, and finally close the inner door. Note that it is prohibited to open either door while the UV lamp is on to prevent UV radiation leakage and potential injury.   5. Maintenance and Calibration Details Daily maintenance of the air shower room includes checking that the fan is running without abnormal noise, the sensing device is sensitive, and the interlock function is working correctly; weekly maintenance includes cleaning the pre-filters, wiping the nozzles, and checking that the door seals are not damaged; monthly maintenance includes checking the integrity of the HEPA filter (PAO leak test) and calibrating the airflow speed to be no less than 25 m/s; every six months, the pre-filters should be replaced and the fan motor should be inspected.   Daily maintenance of the transfer window includes checking that the interlock function is working correctly, the UV lamp indicator light is on (for models with disinfection), and the observation window is free of stains; weekly maintenance includes wiping the internal surfaces with 75% ethanol and checking that the door hinges rotate smoothly; monthly maintenance includes calibrating the UV lamp irradiation intensity (which must reach a bactericidal threshold of ≥70 μW/cm²) and replacing aging seals; quarterly maintenance includes replacing the UV lamp tubes (which typically have a lifespan of 8000 hours).    III. Complementary Functions  The air shower room addresses the active purification of personnel and large material carriers, preventing the entry of large amounts of contaminants into the clean area; the transfer window addresses the sterile isolation and transfer of small items, avoiding disruption of the clean area pressure difference and environmental stability due to frequent door openings. Both are indispensable and together constitute a comprehensive pollution control system for personnel and material entry and exit in the clean area.