CN115183958A - Method for measuring airtightness of clean room - Google Patents
Method for measuring airtightness of clean room Download PDFInfo
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- CN115183958A CN115183958A CN202210732982.8A CN202210732982A CN115183958A CN 115183958 A CN115183958 A CN 115183958A CN 202210732982 A CN202210732982 A CN 202210732982A CN 115183958 A CN115183958 A CN 115183958A
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- clean room
- air
- particle concentration
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
- G01M3/32—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
- G01N15/06—Investigating concentration of particle suspensions
Abstract
The invention relates to the technical field of indoor pollution control, and discloses a method for measuring the airtightness of a clean room. The measuring method calculates the air infiltration quantity of the clean room by measuring the air quantity and the particle concentration of an upper technical interlayer and a lower technical interlayer of the clean room system and a fresh air handling unit and the particle concentration outside the clean room system, thereby reducing the workload and accurately and conveniently measuring the sealing condition of the clean room.
Description
Technical Field
The invention relates to the technical field of indoor pollution control, in particular to a method for measuring the airtightness of a clean room.
Background
With the development of science and technology, the requirements of more and more technical fields on the environment are improved, and the parameters of cleanliness, indoor pressure and the like in the environment are required to be controlled within a specified range, so that the clean room is invented. Usually, a clean room enclosure structure is arranged around a clean room, and a clean room purifying air conditioning system is arranged, wherein the clean room enclosure structure system and the purifying air conditioning system work together and cooperate, and through removing and purifying pollutants such as corpuscles, harmful air, microorganisms and the like in a certain space environment, the cleanliness level, the pressure, the microorganism limit and the like in the certain space environment can meet the specified requirements.
To ensure cleanliness levels within a clean room, the clean room is typically maintained at a pressure differential with the ambient environment of the clean room. So as to prevent the air of the surrounding environment from entering the clean room through the clean room enclosure structure and influencing the cleanliness grade in the clean room. If dirty air in the surrounding environment of the clean room enters the clean room through the enclosure structure, on one hand, the cleanliness grade in the clean room is influenced, and on the other hand, the service life of the high-efficiency or ultra-high-efficiency air filter is shortened. In the prior art, if the problem of poor sealing performance of a clean room occurs, the air supply quantity of a fresh air handling unit is increased so as to maintain the pressure difference required by the clean room. However, this kind of processing scheme is not energy-saving on one hand, and on the other hand, if the sealing performance of the clean room enclosure is poor, the fresh air handling unit does not necessarily have enough margin to compensate for air leakage. Therefore, after the construction of the clean room is completed, the tightness of the clean room is usually tested to determine whether the tightness of the clean room meets the requirements.
In the prior art, a light leakage method, a particle counter scanning method, an air leakage method and the like are generally adopted for testing the airtightness of a clean room. The light leakage method is to introduce a light source into a connecting seam of the clean room enclosure structure and observe whether light penetrates through the seam, so as to judge the airtightness of the clean room enclosure structure. However, the method can only be used for qualitatively judging the sealing performance of the clean room, cannot obtain quantitative data, can only be used for roughly judging, and cannot detect non-straight-through gaps.
The particle counter scanning method is to scan the connecting seam of the clean room enclosure structure with the particle counter and to judge whether the seam leaks air based on the reading value of the particle counter. Although this method can find the air leakage point of the clean room enclosure, the workload is too large for the large clean room with the same volume of the flat panel display and the semiconductor factory building. In addition, because of the structure of the clean room, some joint personnel and instruments cannot reach the joint, so that the joint is rarely adopted in practical engineering.
The air leakage method is to seal the clean room to be tested, i.e. to block the air inlet, air outlet and other openings, and then to maintain certain air pressure inside the clean room by using air filter set or blower. This test method is effective for a clean room with a small volume, but similarly, for a large clean room such as a flat panel display and a semiconductor factory, the number of openings of various clean rooms to be plugged before testing is too large, and the method is not practical.
Therefore, it is still difficult for the prior art to accurately determine the tightness of the clean room while reducing the workload.
Disclosure of Invention
The invention discloses a method for measuring the airtightness of a clean room, which can calculate the air infiltration rate of the clean room by measuring the air rate and the particle concentration of each part of the clean room, thereby reducing the workload and accurately measuring the airtightness of the clean room.
In order to achieve the purpose, the invention provides the following technical scheme:
a method for determining the sealing performance of a clean room, which is used for determining the sealing performance of the clean room in a clean room system; the clean room system comprises a clean room, a clean room enclosure structure and a clean room purifying and air conditioning system; the clean room enclosure structure comprises an upper technical interlayer positioned at the top of the clean room, a lower technical interlayer positioned at the bottom of the clean room and an air return channel connected between the upper technical interlayer and the lower technical interlayer; the clean room purification air conditioning system comprises a fresh air handling unit, a fan filter unit arranged at the top of the clean room and a dry cooling coil arranged in the lower technical interlayer; the assay method comprises:
acquiring the air output of the clean room of the upper technical interlayer, the air return quantity of the clean room of the lower technical interlayer and the fresh air quantity of the fresh air handling unit;
acquiring the particle concentration of the upper technical interlayer, the particle concentration of the lower technical interlayer, the particle concentration of an air supply outlet of the fresh air handling unit and the particle concentration outside the clean room;
calculating the air infiltration volume of the clean room enclosure structure according to the air supply volume of the clean room of the upper technical interlayer, the air return volume of the clean room of the lower technical interlayer, the fresh air volume of the fresh air processing unit, the particle concentration of the upper technical interlayer, the particle concentration of the lower technical interlayer, the particle concentration of the air supply opening of the fresh air processing unit and the particle concentration outside the clean room;
and comparing the air infiltration quantity of the clean room enclosure structure with the standard value of the air infiltration quantity of the clean room enclosure to evaluate the air tightness of the clean room.
Optionally, the calculating according to the clean room air volume of the upper technical interlayer, the clean room air return volume of the lower technical interlayer, the fresh air volume of the fresh air handling unit, the particle concentration of the upper technical interlayer, the particle concentration of the lower technical interlayer, the particle concentration of the air supply opening of the fresh air handling unit, and the particle concentration outside the clean room obtains the air infiltration volume of the clean room enclosure structure, and the calculating includes:
calculating the air infiltration quantity of the clean room enclosure structure by adopting the following formula:
Ls＝(Lt·Ct-Lr·Cr-Lx·Cx)/Cs；
wherein Ls is the air infiltration volume of the clean room enclosure structure, lt is the air output of the clean room of the upper technical interlayer, ct is the particle concentration of the upper technical interlayer, lr is the air return volume of the clean room of the lower technical interlayer, cr is the particle concentration of the lower technical interlayer, lx is the fresh air volume of the fresh air handling unit, cx is the particle concentration of the air outlet of the fresh air handling unit, and Cs is the particle concentration outside the clean room.
Optionally, obtaining the particle concentration of the upper technology interlayer comprises:
a first concentration of particles at an inlet of the fan filter bank is determined.
Optionally, obtaining the particle concentration of the lower technology interlayer comprises:
a second particle concentration at the dry cooling coil is determined.
Optionally, determining the second particle concentration at the dry cooling coil comprises:
and (4) determining the particle concentration at the air inlet of the dry cooling coil or the particle concentration at the air outlet of the dry cooling coil.
Optionally, obtaining the amount of clean room air delivered by the upper technical interlayer comprises:
and obtaining the air output of the clean room according to the debugging and acceptance result of the clean room.
Optionally, obtaining the clean room return air for the lower technology mezzanine comprises:
the amount of air passing through the dry cooling coil was measured.
Optionally, determining the amount of air passing through the dry cooling coil comprises:
and measuring the air speed at the air inlet of the dry cooling coil or the air speed at the air outlet of the dry cooling coil and the area of the dry cooling coil.
Drawings
FIG. 1 is a simplified schematic diagram of a clean room system according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a method for determining the sealing performance of a clean room according to an embodiment of the present invention.
Reference numerals:
1-a clean room; 2-upper technical interlayer; 3-lower technical interlayer; 4-return air channel;
5-a fan filter unit; 6-dry cooling coil; 7-waffle slab; 8-raised floor;
9-fresh air handling unit.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a method for measuring the sealing performance of a clean room, which is used for measuring the sealing performance of the clean room in a clean room system. The clean room system comprises a clean room 1, a clean room enclosure and a clean room purifying and air conditioning system. As shown in fig. 1, the clean room enclosure comprises an upper technical interlayer 2 located at the top of the clean room 1, a lower technical interlayer 3 located at the bottom of the clean room 1, and a return air duct 4 connected between the upper technical interlayer 2 and the lower technical interlayer 3. The clean room clean Air conditioning system includes a fresh Air handling Unit (MAU) 9, a Fan Filter Unit (FFU) 5 disposed on the top of the clean room 1, and a Dry Cooling Coil (DCC) 6 disposed on the lower technical interlayer 3. It should be understood that the fresh air handling unit 9 is connected to the clean room by piping, and the piping is omitted here. In addition, in order to facilitate the air from the clean room to enter the lower technical interlayer 3, an open-pored raised floor 8 and a waffle plate 7 are provided between the lower technical interlayer 3 and the clean room 1.
In practice, however, since the clean room 1 usually has a positive pressure of 10Pa to 20Pa with respect to the surroundings, the raised floor 8 and the wafer sheet 7 themselves have an air resistance of 3Pa to 5Pa during the air passage from the open-pored raised floor 8 and the wafer sheet 7 into the lower sandwich 3, and therefore the lower sandwich 3 usually has a positive pressure of 5Pa-17Pa with respect to the surroundings. The air in the lower sandwich 3 then passes through the dry cooling coil 6 and enters the return air duct 4, and since the dry cooling coil 6 usually has an air resistance of about 40Pa, a negative pressure of-35 Pa to-23 Pa is usually present in the return air duct 4 relative to the ambient environment. The pressure of the upper technical interlayer 2 connected with the return air channel 4 is lower than the pressure in the return air channel 4, so that the clean room system can be divided into a positive pressure area and a negative pressure area. Wherein the clean room 1 and the lower technical interlayer 3 are positive pressure areas, and the return air interlayer 4 and the upper technical interlayer 2 are negative pressure areas. In the vicinity of the negative pressure zone, due to the pressure difference, the dirty air around the clean room system will permeate into the return air channel 4 and the upper technical interlayer 2 through the gaps of the clean room enclosure, and the dirty air is directly mixed with the clean air in the circulation without any filtering measure and enters the fan filter unit 5. This affects the cleanliness class in the clean room system on the one hand and also shortens the filter life of the fan filter unit 5 on the other hand. Therefore, clean room density is very important for a clean room system.
The method for determining the sealing performance of the clean room provided by the invention is used for accurately measuring the air quantity permeated by the clean room in the clean room system so as to accurately judge the sealing performance of the clean room, and as shown in figure 2, the method for determining the sealing performance of the clean room comprises the following steps:
s1: acquiring the air output of a clean room of an upper technical interlayer, the air return quantity of a clean room of a lower technical interlayer and the fresh air quantity of a fresh air handling unit;
s2: acquiring the particle concentration of the upper technical interlayer, the particle concentration of the lower technical interlayer, the particle concentration of an air supply outlet of a fresh air handling unit and the particle concentration outside a clean room;
s3: calculating the air infiltration volume of the clean room enclosure structure according to the air output of the clean room of the upper technical interlayer, the air return volume of the clean room of the lower technical interlayer, the fresh air volume of the fresh air processing unit, the particle concentration of the upper technical interlayer, the particle concentration of the lower technical interlayer, the particle concentration of the air outlet of the fresh air processing unit and the particle concentration outside the clean room;
s4: and comparing the air infiltration quantity of the clean room enclosure structure with the standard value of the air infiltration quantity of the clean room enclosure to evaluate the air tightness of the clean room.
Because the whole clean room system is a closed environment, circulating air enters the return air channel 4 from the lower technical interlayer 3, is mixed with permeated air and air sent by the fresh air processing unit 9, is finally mixed into the upper technical interlayer 2, and enters the clean room 1 through the fan filter unit 5. Therefore, the total of the number of particles in the lower technical sandwich 3, the number of particles sent by the fresh air handling unit 9, and the number of particles penetrating into the air can be obtained as the number of particles in the upper technical sandwich. And the air output of the clean room of the upper technical interlayer 2 corresponds to the concentration of the particles in the upper technical interlayer 2, the air output of the clean room of the lower technical interlayer 3 corresponds to the concentration of the particles in the lower technical interlayer 3, and the air output of the fresh air processing unit 9 corresponds to the concentration of the particles at the air output of the fresh air processing unit, so that the air output of the enclosure structure of the clean room at the infiltration position and the concentration of the particles outside the clean room also correspond to each other. In the case of measuring several other parameters, the air quantity of the air to be permeated can be accurately calculated. In a specific application, the order of step S1 and step S2 may be exchanged, and is not limited. The sequence of acquiring the air volume parameters of different positions of the clean room in the step S1 is not limited, and the sequence of acquiring the particle concentration parameters of different positions of the clean room in the step S3 is not limited.
Meanwhile, the numerical value of the air infiltration quantity can be accurately calculated, and the calculated numerical value can be compared with a standard value required to be compared, so that the condition of the airtightness of the clean room is obtained, and more accurate evaluation is carried out.
Specifically, the following laws exist in the air volume and the particle concentration at each position of the clean room system:
Lr·Cr+Lx·Cx+Ls·Cs＝Lt·Ct；
wherein Ls is the infiltration air volume of the clean room enclosure structure, lt is the clean room air volume of the upper technical interlayer 2, ct is the particle concentration of the upper technical interlayer 2, lr is the clean room return air volume of the lower technical interlayer 3, cr is the particle concentration of the lower technical interlayer 3, lx is the fresh air volume of the fresh air processing unit 9, cx is the particle concentration of the air supply outlet of the fresh air processing unit 9, and Cs is the particle concentration outside the clean room.
Therefore, the amount of air infiltration into the clean room can be calculated using the following formula:
Ls＝(Lt·Ct-Lr·Cr-Lx·Cx)/Cs；
that is, the amount of air permeated into the clean room enclosure is calculated by dividing the total number of particles permeated by the number of particles introduced into the clean room enclosure by the concentration of particles in the permeated portion, i.e., the concentration of particles outside the clean room system, and the total number of particles permeated is calculated by subtracting the number of particles in the upper technical interlayer 2 from the number of particles in the lower technical interlayer 3 from the number of particles sent by the fresh air handling unit 9. The calculation method of the number of particles at the upper technical interlayer 2 is the product of the air volume of the clean room at the upper technical interlayer 2 and the particle concentration, the calculation method of the number of particles at the lower technical interlayer 3 is the product of the air volume of the clean room at the lower technical interlayer 3 and the particle concentration, and the calculation method of the number of particles fed by the fresh air handling unit 9 is the product of the fresh air volume and the particle concentration of the air inlet of the fresh air handling unit.
Specifically, since the air in the upper technology interlayer 2 will eventually enter the clean room through the fan filter unit 5, the particle concentration and the clean room air supply amount at the upper technology interlayer 2 can be obtained by measuring the particle concentration and the air supply amount at the inlet of the fan filter unit 5. Similarly, since the air in the lower interlayer 3 will finally pass through the dry cooling coil 6 and enter the return air duct 4, the particle concentration and the clean room return air volume in the lower interlayer 3 can be obtained by measuring the particle concentration and the air volume in the dry cooling coil 6. Meanwhile, due to the different specific structures of different clean rooms, the particle concentration and the air volume of other structures of the technical interlayer 2 can be measured according to actual conditions, and the obtained results can be regarded as the particle concentration and the air volume of the clean room of the technical interlayer 2. Similarly, the particle concentration and the air volume can be measured for other structures of the lower technical interlayer 3 as is, and the obtained results can be regarded as the particle concentration and the clean room return air volume of the lower technical interlayer 3.
Specifically, the particle concentration and the air volume of the dry cooling coil 6 can be measured at the air inlet of the dry cooling coil 6, the air outlet of the dry cooling coil 6, and both the air inlet and the air outlet of the dry cooling coil 6. The data measured at the air outlet of the dry cooling coil 6 is more accurate, but the data can be measured at the air inlet of the dry cooling coil 6 for convenient operation.
In addition, because the fresh air volume sent by the fresh air processing unit 9 and the air volume sent by the fan filter unit 5 in the clean room purifying air conditioning system are basically fixed and unchangeable within a certain time, namely after the clean room system is built, the two numerical values are basically fixed and unchangeable within a certain time, the numerical values can be directly obtained through the debugging and acceptance results of the clean room system and applied to subsequent calculation.
The present invention may employ an apparatus for determining a clean room hermeticity for performing the above-described determination method to determine the clean room hermeticity of a clean room system. The measuring device comprises a clean room system, a particle counter and an anemometer. The wind meter is used for detecting wind quantity of a part needing to be measured, and the particle counter is used for measuring particle concentration of the part needing to be measured. And calculating the air infiltration amount of the clean room enclosure structure through the measured air amount and the particle concentration, and comparing the air infiltration amount with the standard parameters of the air leakage amount of the clean room to obtain a final clean room airtightness result. In the measuring process, the particle counter is respectively arranged at the position of the fan filter unit 5, the air inlet or the air supply port of the dry cooling coil 6, the position of the fresh air processing unit 9 and the outer parts of the return air channel 4 and the upper technical interlayer 2 in sequence. It should be noted that the determination sequence is not specified, and may be changed according to actual situations.
It will be apparent to those skilled in the art that various changes and modifications may be made in the embodiments of the invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (8)
1. The method for determining the airtightness of the clean room is characterized in that the method is used for determining the airtightness of the clean room in a clean room system; the clean room system comprises a clean room, a clean room enclosure structure and a clean room purifying and air conditioning system; the clean room enclosure structure comprises an upper technical interlayer positioned at the top of the clean room, a lower technical interlayer positioned at the bottom of the clean room and an air return channel connected between the upper technical interlayer and the lower technical interlayer; the clean room purification air conditioning system comprises a fresh air handling unit, a fan filter unit arranged at the top of the clean room and a dry cooling coil arranged in the lower technical interlayer; the assay method comprises:
acquiring the air output of the clean room of the upper technical interlayer, the air return quantity of the clean room of the lower technical interlayer and the fresh air quantity of the fresh air handling unit;
acquiring the particle concentration of the upper technical interlayer, the particle concentration of the lower technical interlayer, the particle concentration of an air supply outlet of the fresh air handling unit and the particle concentration outside the clean room;
calculating the air infiltration volume of the clean room enclosure structure according to the air output of the clean room of the upper technical interlayer, the air return volume of the clean room of the lower technical interlayer, the fresh air volume of the fresh air processing unit, the particle concentration of the upper technical interlayer, the particle concentration of the lower technical interlayer, the particle concentration of the air outlet of the fresh air processing unit and the particle concentration outside the clean room;
and comparing the air infiltration quantity of the clean room enclosure structure with the standard value of the air infiltration quantity of the clean room enclosure to evaluate the air tightness of the clean room.
2. The method for determining the sealing performance of a clean room according to claim 1, wherein the amount of air infiltration into the clean room enclosure is calculated from the amount of air blown into the clean room by the upper technical interlayer, the amount of air returned into the clean room by the lower technical interlayer, and the amount of fresh air from the fresh air handling unit, the particle concentration in the upper technical interlayer, the particle concentration in the lower technical interlayer, the particle concentration in the air outlet of the fresh air handling unit, and the particle concentration outside the clean room, and the method comprises the steps of:
calculating the air infiltration quantity of the clean room enclosure structure by adopting the following formula:
Ls＝(Lt·Ct-Lr·Cr-Lx·Cx)/Cs；
wherein Ls is the air infiltration volume of the clean room enclosure structure, lt is the air output of the clean room of the upper technical interlayer, ct is the particle concentration of the upper technical interlayer, lr is the air return volume of the clean room of the lower technical interlayer, cr is the particle concentration of the lower technical interlayer, lx is the fresh air volume of the fresh air handling unit, cx is the particle concentration of the air outlet of the fresh air handling unit, and Cs is the particle concentration outside the clean room.
3. The method for determining clean room hermeticity according to claim 1, wherein obtaining the particle concentration of the upper technology interlayer comprises:
and measuring the particle concentration at the inlet of the fan filter unit.
4. The method for determining the tightness of a clean room according to claim 1, wherein obtaining the particle concentration of said technical interlayer comprises:
and measuring the particle concentration at the air inlet of the dry cooling coil or the particle concentration at the air outlet of the dry cooling coil.
5. The method for determining the airtightness of a clean room according to claim 1, wherein the obtaining of the air volume of the upper technical interlayer comprises:
and obtaining the air output of the clean room according to the debugging and acceptance result of the clean room.
6. The method for determining the airtightness of the clean room according to claim 1, wherein the step of obtaining the fresh air volume of the fresh air handling unit comprises:
and obtaining the fresh air volume of the fresh air handling unit according to the debugging and acceptance result of the clean room.
7. The method for determining clean room air tightness according to claim 1, wherein obtaining the clean room air return of the technical interlayer comprises:
the amount of air passing through the dry cooling coil was measured.
8. The method of claim 7, wherein determining the amount of air passing through the dry cooling coil comprises:
and measuring the air speed at the air inlet of the dry cooling coil or the air speed at the air outlet of the dry cooling coil, and the area of the dry cooling coil.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115585959A (en) * | 2022-11-08 | 2023-01-10 | 江苏雷默智能科技有限公司 | Sealing strip evaluation method and system for purifying space |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115585959A (en) * | 2022-11-08 | 2023-01-10 | 江苏雷默智能科技有限公司 | Sealing strip evaluation method and system for purifying space |
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