How to properly use and maintain the pass box to ensure its performance and cleanliness?

1. Use the pass box correctly
Code of practice for delivery of goods
When using the pass box to deliver items, you should first place the items in the delivery window, close the door on one side, and then open the door on the other side to remove the items. For example, when transferring pharmaceutical raw materials in the pharmaceutical workshop, the staff should ensure that the interlock device of the pass box works properly and the doors on both sides cannot be opened at the same time. Opening the door at the same time will destroy the isolation function of the pass box, resulting in direct air convection in different clean areas, so that pollutants in the lower cleanliness area will enter the higher cleanliness area, affecting the quality of drugs.
For some large or irregularly shaped items, pay attention to the way they are placed to avoid obstructing the airflow channel inside the transfer window. For example, when transferring a large circuit board in an electronics workshop, the circuit board should be placed flat in the transfer window to ensure that laminar flow or other airflow can flow smoothly through the surface of the circuit board to play the role of purification and isolation.
Follow clean room workflow.
When using the pass box, it is necessary to work closely with the workflow of the entire clean room. Before entering the clean room, staff should be familiar with the routes and requirements for the transfer of items between different areas. For example, in a semiconductor manufacturing clean room, the transfer of silicon wafers from the lithographic zone to the etching zone is performed by the specified transfer time and sequence. If the transmission is not timely, it may cause the silicon wafer to stay in the pass box for too long, increasing the risk of contamination; If the transmission sequence is wrong, it may make the silicon wafer not meet the cleanliness requirements of the etching area enter the area, affecting the quality of the product.
In addition, staff in different clean areas should strictly follow the clean operating procedures of their respective areas when using the transfer window. For example, in the food processing cleaning shop, workers in the high cleanliness area may need to perform additional cleaning steps such as hand disinfection before opening the transfer window to pick up items to prevent the introduction of external contaminants into the high cleanliness area.
Precautions for the use of special types of transfer Windows
Laminar flow pass box: Pay attention to the direction and speed of laminar flow when using. In general, after opening the laminar flow pass box, you need to wait for some time for the laminar flow to stabilize before placing items. For example, in the aseptic transfer process of biopharmaceuticals, it is necessary to ensure that the item is placed in the direction of the laminar flow of air so that the laminar air can effectively purify the surface of the item. Moreover, the wind speed of the laminar flow pass box is usually within a specified range, too low wind speed may not be able to effectively remove pollutants on the surface of the item, and too high wind speed may cause the item to shift or even damage.
Air shower pass box: After placing items, ensure that the air shower process is complete. The air shower time of the air shower pass box can generally be set, and different items and cleanliness requirements may require different air shower times. For example, in the precision optical instrument manufacturing workshop, for high-precision lens transfer, it may take a long air shower time to completely remove the tiny dust on the surface of the lens. At the same time, pay attention to the cleaning of the interior of the air shower pass box, because the pollutants blown off during the air shower process will accumulate in the interior, and if it is not cleaned up in time, it may pollute the delivered items again.
Vacuum pass box: When using the vacuum transfer window, the process of vacuuming and restoring normal pressure should be carried out in strict accordance with the operating procedures. For some pressure-sensitive items, such as fragile biological samples or special chemical materials, it is necessary to control the speed and degree of vacuuming to avoid damage to the items. Moreover, after the transfer is completed, check the sealing performance of the vacuum transfer window to ensure that there is no air leakage, because leakage may cause outside air to enter and affect the effect of the next transfer.
2. Maintenance measures of pass box
Cleaning work
External cleaning: Clean the outer surface of the pass box regularly, and wipe the shell with a clean damp cloth to remove dust and stains. During the cleaning process, care should be taken to avoid moisture entering the inside of the pass box. For example, in a clean laboratory of the hospital, the outer surface of the transmission window should be cleaned at least once a week to prevent the microorganisms in the dust from breeding and spreading to the interior through personnel contact and other ways.
Internal cleaning: For the interior of the pass box, the frequency of cleaning depends on the use. If it is in a high pollution risk environment, such as a chemical workshop, it may be necessary to clean the interior every day. When cleaning, first turn off the power to the transfer window (if any), and then clean it from the inside out with special cleaning tools and cleaners. For the nooks and crannies inside, pay special attention to cleaning, as these places tend to accumulate dust and pollutants. In the electronic cleaning workshop, use non-fiber cleaning cloths and electronic-grade cleaners to clean the interior of the transfer window to avoid fiber residue and chemical contamination.
Component inspection and replacement
Filter inspection and replacement: The air filter in the pass box is a key component to ensure clean results. Check the status of the filter regularly to see if there is blockage, damage, etc. In general, the primary filter is checked every 1-3 months, and the medium and high-efficiency filter is checked every 3-6 months. If it is found that the filter resistance increases (can be judged by monitoring the pressure difference before and after the filter) or there is damage, it should be replaced in time. For example, in a class 100,000 clean workshop of a pharmaceutical company, after the resistance of the HEPA filter exceeds the specified value, it needs to be replaced immediately to ensure that the air quality in the transfer window meets the requirements.
Fan check: The fan is an important part of ensuring the normal circulation of air inside the pass box. It is necessary to check the operation of the fan regularly, including the speed of the fan, noise, vibration, etc. If the fan is found to be operating abnormally, such as a significant decrease in speed, increased noise, or severe vibration, the fan should be repaired or replaced in time. In some biological laboratories with high cleanliness requirements, a simple inspection of the transfer window fan should be carried out every month, and comprehensive maintenance should be carried out every six months.
Interlock device inspection: The interlock device is the key to ensure that the doors on both sides of the pass box cannot be opened at the same time. The function of the interlock device should be checked regularly to ensure that it works properly. You can check whether the interlock device is sensitive and reliable by simulating the opening of the door. In places such as food processing workshops, the interlock device of the pass box should be checked every time the equipment is maintained to avoid cross-contamination caused by the failure of the interlock device.
Performance testing and calibration
Airflow testing: The airflow organization of the pass box is tested regularly, including airflow speed, direction, and uniformity. For laminar flow transfer Windows, professional airflow testing instruments, such as a hot wire anemometer, should be used to measure whether the speed of laminar flow meets the design requirements. In the electronic chip manufacturing clean room, the airflow of the laminar flow pass box is tested every quarter to ensure that the laminar flow speed is within the specified range, such as 0.3-0.5m /s, to ensure the cleanliness of the chip in the transfer process.
Tightness test: the tightness of the pass box directly affects its isolation effect. The tightness of the transfer window can be checked through methods such as pressure attenuation testing. Pressure the inside of the pass box to a certain extent, and then observe the pressure attenuation, if the pressure drops too fast, it indicates that there is a sealing problem. In the medical device manufacturing clean room, the tightness of the pass box is tested at least once a year to ensure that no air leaks and prevent outside contaminants from entering the clean area.
Purification effect test: To ensure the purification function of the pass box, the purification effect test should be carried out regularly. The purification can be evaluated by placing test particles (such as the standard particles used by dust particle counters) inside the pass box and then checking for a reduction in the number of particles after passing through the pass box. In the clean room of the pharmaceutical and electronics industries, according to the requirements of different cleanliness levels, the purification effect is tested regularly (such as once every six months) to ensure that the pass box can effectively remove contaminants on the surface of the transfer item.