With the continuous improvement of China's pharmaceutical industry, in accordance with the requirements of international standardization quality, it is very necessary to build a clean plant in compliance with GMP regulations.

   At present, the use of central air conditioning and three-stage filtration is the classical model of purification technology. This requires a dedicated air-conditioned room and about 2m high technical mezzanine, the higher technical requirements of the basic building, suitable for larger new construction projects. However, in the pharmaceutical industry, especially in the biological products industry, many of the production and pilot projects are small in size and many of the old factories also need to be utilized. Due to the structural constraints and costs of the buildings, the above methods have encountered great difficulties.

Generally, the height of the old factory is about 3m, the area and shape are different from the actual needs, and the air duct can not be installed as usual, and the technical mezzanine and the special air-condition system can not be installed. According to the basic principles of air purification, in practice, we explore a very practical method of technological transformation of clean room, especially for small and medium-sized clean room technical transformation. Now introduced as follows:

    1 structure model

    The use of ordinary air-conditioning directly to the main air area to send cold air to transform the clean room schematic diagram clean room built in the old plant, the room height of 3m, clean room walls using sandwich color steel plate construction, about 2.4m high, Fan room, about 0.6 m high, with windbox. Fan room all around the closed, with inward ventilation in the efficiency filter inlet. Fan installed in the wind box, the lower part of the plenum and high efficiency filter. There is no air return filter on the lower side of the clean room, the air return channel is on the outside of the clean room, and the air return channel is communicated with each other. At least one split type air conditioner is provided therein. Air conditioner can be ordinary cabinet with split air conditioners, the outlet is equipped with shrouds and cold duct, the other end of the cold duct installed in the fan room. Under normal circumstances, the air conditioner blower can deliver cold air outside the 15 m, basically to meet the general use of small and medium-sized clean room, when the air supply distance, can be installed in the cold duct fan to increase the supply pressure. It must be noted that the shroud and the cold duct must be heat treated. The thickness of the indoor unit of ordinary cabinet split air conditioners is generally 0.25m ~ 0.35m (air conditioner cooling capacity 5000W ~ 15000W) taking into account the width of the shroud, the width of the return air duct can be made as small as 0.5m ~ 0.7m . When wall-mounted air conditioners are selected, the width of the air return channel can be reduced, and the width of the remaining air return channel can be made as small as 0.1 m. In this way, cleanrooms are designed to maximize the use of building space.

    2 air circulation mode

    Air flow into the plenum by the wind through the high efficiency filter into the clean room, and then from the air filter into the return air inlet wind, some return air flow and fresh air from the filter into the fresh air through the filter efficiency into Fan room, the other part of the return air flow directly into the air inlet, air cooling through the shroud and cold duct into the fan room. Two parts of the flow in the fan chamber after mixing, through the wind box on the efficiency filter by the fan into the plenum, and then through the high efficiency filter into the clean room to form air circulation system. It can be seen from the circulation of the air stream that in fact, a good three-stage filtration state has been formed. Therefore, the clean room air quality has been a reliable guarantee. On this basis, adjust the structure and layout of the high-efficiency filter outlet, with the corresponding air volume, you can determine the cleanliness of the clean room form and cleanliness to suit different needs. The clean room shown in Figure 1, on both sides of which constitutes a local 100 clean air mainstream area, the remaining million clean area.

     3 main technical features and advantages

     3.1 without main air duct and dedicated air-conditioned room, reduce investment

    Air flow in the return air duct and fan room flow, air conditioners are also installed in the return air channel, do not need special air-conditioned room, return air channel in addition to installing air-conditioning, but also for maintenance and process access. Air conditioners are characterized by air supply air pressure at the end of cold air sent by the air conditioner directly into the fan room, in addition to the cold air duct of its own resistance, there is no other resistance loss, especially the cold duct outlet, the wind box to form a certain vacuum Degree, but also help to overcome the cold air supply resistance. Due to the pressure on the cold duct is very low, so the cold duct can choose the lighter quality at the end of the thin plastic or metal hose. The entire air circulation system except for a small amount of auxiliary role of the cold duct, other main duct and pipe valve can be omitted. There is no main air duct in the whole clean room or no special air-conditioned room. The airflow passage is formed by clean room walls and wall panels. Air conditioners are cheap, reliable, and easy to install, saving engineering investment and shortening the construction cycle.

    3.2 air conditioning and rapid cooling, significant energy saving

    Normally, the temperature of the clean room is conditioned by the central air conditioning to cool the air before sending to the clean room. The method requires a large number of ducts for long-distance air supply, resulting in significant energy losses along the way with resistance loss and temperature loss. In addition, there are also air conditioners installed in a dedicated return air straight pipe, and then from the fan and duct to send air to the efficient delivery method, although this method eliminates the need for central air-conditioning, is still in need of special fan and duct , The structure is complex, the cost is high, and occupies a limited space, which is inconvenient to repair and operate the air conditioner, and the energy loss caused by the fan and the air duct is also large. This program uses the cold air duct direct air way, the cold air produced by the air conditioner directly to the mainstream of clean air, cold stroke and the shortest, the most concentrated cold air, without special pipe valve, saving investment, installation and more simple. What's more important is to reduce the resistance loss and temperature loss of these pipe valves so as to achieve the goal of improving the efficiency and saving energy.

    3.3 simple operation, easy maintenance

    No special air-conditioned room, no special operation, the wind box and efficient air filter is set according to need grouping, so maintenance and use can be sub-unit.

    3.4 Make full use of existing plant, tap the potential efficiency

    The use of existing plant transformation clean room, short construction period, the end of the cost, flexible and practical, enterprises tap the potential for efficiency.

    Following this methodology, we conducted a retrofit test of my sterile laboratory at QA. The laboratory area of about 50 square meters, with two partial 100 clean room, are combined with the drawings, with one of the 12 square meters of clean room as an example to introduce the room clean room on both sides of the set 3m wide and 0.8 m clean air mainstream area, covered with high efficiency air filter, set a refrigeration capacity of 7500w cabinet air conditioner for the entire laboratory use, the outlet of the cold air duct is mainly set above the clean room. The mainstream area Cleanliness of 100, the remaining area of 10000, the clean room temperature within 5mim within the rapid decline from 33 ℃ 21.4 ℃, the rest of the room temperature also gradually decreased to about 22 ℃, 20mim after the various parts of the temperature reaches a balance. For the clean room test data, the technical indicators have reached the GMP requirements.According to the actual situation, the remaining rooms also set the corresponding high efficiency air filter outlet and cold duct, the cleanliness of the room and the temperature reached the corresponding Requirements, the entire laboratory design has also achieved the desired purpose.

    It can be seen from the above experiments that the method of sending cold air directly to the mainstream of clean air using ordinary air conditioners not only saves investment, saves energy, and is convenient for installation and use. More importantly, the mainstream airflow is used to enhance the air circulation in the clean area to achieve the purpose of purification. At the same time, a large amount of cold air is sent to the area, causing the temperature to drop rapidly.

    Using this method, we have reworked the G-CSF clean lab and other departments of our blood preparation sub-assembly plant and achieved satisfactory results. After testing the technical indicators have reached the relevant national standards, successfully passed the national GMP certification testing, to ensure the smooth progress of production and scientific research.