With the rapid development of modern industry, the technical content of its products is more complex. In order to adapt to more and more industries, they rely on clean indoor production and assembly of their own products to ensure the stability of equipment quality and high service life. So the modern clean workshop is used in all walks of life. How to ensure that the cleanliness level of modern clean workshop always meets the requirements of production process.
Modern clean workshop technology introduces three categories of clean workshop design and construction, clean workshop test and detection, and clean workshop operation. To understand the control mechanism of positive pressure difference in clean workshop and ensure the energy-saving operation of clean workshop is to meet the urgent requirements of modern industrial production for clean workshop environment.
The clean workshop is first designed by the architectural design institute according to the requirements of the construction unit and the environmental requirements of the industry products. This is the premise work for the design and construction of clean workshop, and it is also the basic work
Operating room purification workshop purification laboratory purification
(I) establishment of differential pressure in clean workshop
The test and detection of the clean workshop is the sub item test and measurement carried out by the construction unit according to the design and construction drawings of the design unit after all the ventilation and air conditioning designs are installed in place, mainly including air volume commissioning and pressure difference commissioning, cleanliness test, and indoor temperature and humidity measurement of the clean workshop.
(1) air volume debugging: according to the design and calculation of the design and construction drawings, the air supply and return pipelines; the size of the design air volume, determine the opening state of the air supply and return valves of each pipeline, and test the air volume of each branch. This article is not going to elaborate.
(2) cleanliness test: it is divided into air condition test, static condition test and dynamic condition test, respectively testing the dust content in the clean workshop.
The test under empty condition refers to the test under the condition that the system (clean workshop) has been in normal operation state, but the process equipment and production personnel have not yet entered.
Static condition test means that the system (clean workshop) has been in normal operation, the process equipment has been installed but not operated, and there is no production personnel in the room.
Dynamic condition test refers to the system (clean workshop) has been in normal operation, and the process equipment and production personnel have been working.

According to the above test results, the construction unit shall test the dust content concentration under different production environment conditions, so as to achieve the cleanliness level required by the construction designer and the construction unit, ensure that the dust concentration is always lower than this value, and deliver it to the construction unit for use.

(3) pressure difference commissioning: in order to prevent the external pollutants from entering the clean workshop and increase the indoor cleanliness, it is required to keep the indoor pressure higher than the external pressure, that is to say, a certain pressure gradient must be maintained for rooms with different cleanliness in the clean workshop, so that the clean workshop can be effectively prevented from being polluted by the adjacent rooms or polluting the adjacent rooms under a certain indoor pressure difference. The process of pressure difference commissioning is to ensure the air change frequency of clean workshop and the effect of equipment ventilation and dust removal, and try not to change the air supply volume and the air volume of equipment exhaust fan and dust removal fan. The pressure difference is mainly adjusted by adjusting the return air volume and the system exhaust air volume. The code for design of clean workshop clearly states that if the indoor pressure of clean workshop is kept higher than the external pressure, it is called positive pressure clean workshop, otherwise it is called negative pressure clean workshop. Positive pressure and negative pressure are relative. A clean workshop is a positive pressure clean workshop for the atmosphere, but it may be a negative pressure clean workshop for another room. It is specified that the pressure difference between clean workshop of different grades and between clean area and non clean area shall not be less than 5pa, and that between clean area and outdoor shall not be less than 10Pa
All functional rooms in the human purification area shall follow the human purification route: unclean corridor, shoe changing, primary dressing room, secondary dressing room, buffer room and clean inner corridor.
Maintain a positive pressure difference of at least 30Pa between the corridor and the non clean area in the clean workshop.
The basic principle of establishing the pressure difference is that the supply air volume is larger than the return air volume, the exhaust air volume and the leakage air volume to maintain the positive pressure. The pressure difference is established when the balance between the incoming air volume and the exhaust air volume + differential pressure air volume (residual air volume) of the clean workshop is achieved.
For fresh air system: fresh air volume = exhaust air volume + differential pressure air volume
For circulating air system: fresh air volume + return air volume = return air volume + exhaust air volume + differential pressure air volume
In the final analysis, the pressure difference in the clean workshop, that is, the new air volume = exhaust air volume + pressure difference air volume, and the balance relationship between them is established.
In a word, design, construction and commissioning are three important links to ensure the normal operation of the purification system. Through commissioning, we can understand the problems in the operation of the system, so as to improve the design scheme, standardize the construction operation and avoid the above problems. Debugging is an important and necessary link to ensure whether the indoor pressure difference and cleanliness of the clean workshop are up to the standard. The normal operation of the system belongs to the normal use and production link.
(II) interference factors and control methods of differential pressure fluctuation in clean workshop:
The change of the outdoor wind pressure and wind speed causes the change of the pressure difference between the clean workshop and the outdoor
For coastal cities and cities with high wind speed, it is necessary to recheck and calculate the head-on wind speed pressure and adjust the pressure difference.
When the air conditioning system is running over time, the resistance of the system will change, mainly due to the change of filter resistance, which causes the change of air supply volume and affects the establishment of the pressure difference in the clean workshop. Because when the resistance of the air conditioning system changes to a certain value after a certain period of operation, the resistance of the system increases and the total air supply volume decreases. The actual air supply volume is less than the set value The supply air volume can not guarantee the establishment of the original indoor pressure difference. At the same time, due to the flow of people in the clean workshop, the doors and windows in the clean workshop are opened frequently, the original sealing performance in the clean workshop is reduced, and serious air leakage will affect the establishment of the original pressure difference in the clean workshop. For the above problems. In order to keep a certain pressure difference in the clean workshop, some measures must be taken to maintain the positive indoor pressure.
(1) install the air damping layer at the return air port;
(2) the exhaust pipe is equipped with a medium efficiency filter with an electric closed valve;
(3) the residual pressure valve is generally set on the wall at the downwind side of the clean workshop. When taking such measures, sufficient residual air volume is required in the room;
(4) adjust the return valve or exhaust valve;
(5) adjust the fresh air valve;
(6) fan and air valve interlock control;
(7) regularly replace some necessary filters.
As a powerful purification engineering company in China, Shandong ed purification Engineering Co., Ltd. has a special project department responsible for the design, production, installation and commissioning of purification in food workshop, cosmetics workshop, printing and packaging workshop, and electronic dust-free workshop. The company integrates professional scheme design team, complete supporting product channels, professional system construction team and perfect after-sales service. With the relevant construction qualification issued by the national construction department; with an experienced engineering technology research and development team; with years of professional accumulation in the field of purification, combined with the construction management practice of many domestic projects, to provide comprehensive and high-quality overall purification system technical support for domestic customers. If you want to know more about the workshop purification construction, please contact the engineering personnel of the project department in detail. For more knowledge of medical purification industry, please pay attention to WeChat public address: Aide-188 (Ed purify oxygen supply).