Clean room purification solution

Purification Solutions

1、Whole room purification

The purification treatment method that creates the same clean environment in the whole room by centralized purification air conditioning system is called whole room purification. This is one of the earliest developed methods in clean technology and is still used today. This method is suitable for the place where the process equipment is tall, the number is large and the room requires the same cleanliness. However, this method has large investment, complicated operation and management, and long construction period.

2、Partial purification

Purification air conditioner or local purification equipment (such as clean bench, shed vertical laminar flow unit, laminar flow hood, etc.), in the general air conditioning environment to cause a local area with a certain cleanliness level environment of purification treatment method called local purification. This way is suitable for the production batch is small or use the original plant for technical transformation. At present, the most widely used is the whole room purification and local purification combined purification processing method, which is the clean technology development purification method, it can ensure that the room has a certain degree of cleanliness, but also in the local area to achieve high cleanliness environment, so as to achieve both to meet the requirements of the production of high cleanliness environment, but also to save energy for dual purposes. For example, when the production batch is small, the operation section which needs class 100 cleanliness can be purified by using local purification equipment such as clean bench or laminar flow hood in the messy flow clean room with low cleanliness, so as to realize the purification method combining whole room purification and local purification.

3、Clean tunnel

The purification treatment method that consists of two laminar flow process areas and the chaotic flow operation activity area in the middle to form a tunnel-shaped clean environment is called clean tunnel. This is a typical combination of whole-room purification and local purification, and is the purification method currently being promoted, and is also called the third generation purification method.

According to the different equipment composing the clean tunnel, the clean tunnel can be divided into the following forms.

(1) Benchtop clean tunnel

This form of clean tunnel is to connect clean benches with each other and eliminate the middle side wall to form a tunnel type production line for production needs. When the process requires vertical laminar flow, the vertical laminar flow workbench can be used. When the process requires horizontal laminar flow, the horizontal laminar flow workbench is used. This purification method is easier to ensure the high cleanliness of the local space than the whole room purification, and can reduce or prevent cross-contamination because the benches are connected with each other. In addition, the requirements for the building are relatively simple, only the environment of a messy flow clean room is required. The disadvantage is that the size of the clean bench is fixed, so that the operating surface lacks sufficient flexibility, and the process equipment must adapt to the size of the bench, and it is not very convenient to adjust.

(2) Shed type clean tunnel

This form of clean tunnel is composed of a clean shed, i.e. a shed-type vertical laminar flow unit connected in series in a production line. According to the process requirements, the area of the clean shed can be varied, and the air can be all indoor circulating type, or connected to the centralized purification air conditioning system to draw some new air. The shed type clean tunnel is suitable for places with large process equipment.

(3) Hooded clean tunnel

This form of clean tunnel is formed by connecting laminar flow hoods, i.e. hooded vertical laminar flow units, in series on a production line. Since the depth of the laminar flow hood is smaller than that of the clean shed, it is only suitable for places where the process equipment is small. The air circulation method is the same as that of the shed type clean tunnel and the table type clean tunnel, and it is one of the clean tunnels that are currently used more often.

(4) Centralized air supply type clean tunnel

This form of clean tunnel is composed of a static pressure box full of high efficiency filters with a centralized air supply system. The width of the laminar flow working area can be determined according to the requirements of the process, unlike bench, shed and hood type clean tunnels, where the width of the laminar flow working area is not limited by the size of the local purification equipment, and the design can be more flexible. With this form, the return air can pass through a technical mezzanine or, as in the figure, a trench can be set up in the active area of the turbulent flow operation. In addition, industrial ducting can be arranged on the side of the work area along the wall panel, with the exhaust air duct connected to the gutter.

The characteristics of the clean tunnel are as follows：

(1) It causes different cleanliness in the tunnel, thus making full use of the characteristics of different clean airflow to meet the process requirements to the maximum extent. Generally, the tunnel is flanked by a high cleanliness laminar flow work area and a turbulent flow operation activity area in the middle. The process areas are connected into a line, which is easy to use and the activities of personnel do not cause cross contamination.

(2) Due to the reduction of laminar flow area in the tunnel, the infrastructure cost and operation cost are more than one-third saving than the vertical laminar flow clean room with full room purification. The net height of the turbulent flow activity operation area is much higher than that of the laminar flow process area, which can meet the requirements of personnel comfort.

(3) The technical mezzanine can be used as a return air duct, and can also arrange various industrial ducts and install process auxiliary equipment. The maintenance of the local purification equipment (clean bench, clean shed and laminar flow hood, etc.), industrial ducts and process auxiliary equipment that make up the clean tunnel can be carried out in the technical mezzanine. Since the technical mezzanine is negative pressure compared with the clean tunnel, the maintenance work will not cause pollution in the clean tunnel, and the maintenance work can be carried out without stopping the process production.

The components required for the clean tunnel, such as local purification equipment, roof, wall panels, air return vents and doors and windows, can be standardized and modulized, processed and produced by professional factories and assembled on site. At the same time, the clean tunnel can be disassembled and reassembled quickly, which provides convenience for process changes.

(4) clean tunnel can be configured according to a certain scale purification air conditioning system, so the air conditioning system can be generalized and serialized, which can greatly reduce the design cycle.

(5) In general, clean tunnels have relatively simple requirements for construction, as long as they have the environment of a messy flow clean room, they can meet the requirements.

4、Clean pipeline

The purification treatment method of putting the process line that needs ultra-high cleanliness level (such as class 1 or class 10) in a duct isolated from indoor air environment is called clean duct. This method requires that the process production must be automated and the high efficiency filter must be 0.1μm dust particles in order to achieve ultra-high cleanliness. In addition, this way, because the air being purified is in the duct, the air supply and return volume is very small, so it can save energy substantially, which is the development direction of clean technology and is also called the fourth generation purification method.

The purification treatment options described above need to be determined on a case-by-case basis.

At present, the technical development has been more mature is the whole room purification, local purification (including the whole room purification and local purification combined) and clean tunnel three kinds of purification treatment, engineering design should be combined with the specific situation to choose one or two purification methods as a design scheme.

Under the condition of meeting the process requirements, local purification method should be used as much as possible. Local purification adopts local purification equipment, which is realized in general air conditioning environment. Because local purification equipment are generally produced by professional factories, high quality equipment, and can speed up the site construction, in the reconstruction project can give priority to this solution.

When only the local purification method cannot meet the process requirements, a combination of local purification and whole room purification can be used as the design solution.

When the above purification methods are not able to meet the process requirements, only then choose the whole room purification purification method as the design scheme. Because this way to cause the whole room has the same cleanliness, especially when the cleanliness level is high, the initial investment and operating costs are very high, therefore, the area of the clean room should be strictly controlled.