DEHUMIDIFICATION/HUMIDIFICATION AIR SUPPLY APPARATUS

Abstract: A dehumidified/humidified air supply apparatus comprises two sets of air passages (A, B) including heating units (5, 6) disposed at an upstream side thereof, a dehumidifying/humidifiying unit (10) having two portions 10a, 10b disposed at a downstream side thereof and a blower 2, wherein when dehumidified air is supplied by the dehumidifying/humidifying unit (10) of the first air passage (A), the dehumidifying/humidifying unit (10) is dehumidified by air which is heated by the heating unit (6) of the second air passage (B), and when humidified air is supplied by the heating unit (5) of the first air passage (A) and the dehumidifying/humidifying unit (10), the dehumidifying/humidifying unit (10) is humidified by air of the second air passage (B). The dehumidifying/humidifying unit (10) is moved between the first air passage (A) and the second air passage (B) by a driving unit (17).

Description: Technical Field The present invention relates to a dehumidified/humidified air supply apparatus for keeping the inside of a semiconductor production apparatus, etc. at a fixed humidity. Background Art In order to dehumidify the inside of a semiconductor production apparatus or the like, it has been hitherto adopted that a refrigerating machine is installed directly to a semiconductor production apparatus and the inside air is cooled until a targeted dew point by the refrigerating machine to liquefy and remove the moisture in the air and then circulated in the semiconductor production apparatus. The refrigerating machine contains a compressor, a condenser, an evaporator, etc. and thus it has a vibration problem. Further, the condenser needs means for radiating heat to the outside and the construction is complicated. A heat exchanger and an electric heater are required to adjust the humidity of the inside of the semiconductor production apparatus. In addition, means for discharging water which is liquefied and removed for dehumidification and means for supplying water for humidification are needed. JP-09-126493 discloses a heat exchanger ventilating apparatus. Heating means heat room air sucked into a main body by blowing means during humidifying, and heat outside-of-room air during dehumidifying. A heat exchanger rotor is provided with an air path portion allowing the room air and the outside-of-room air to flow through and is rotated by dynamic pressure of the air blown by the blowing means. Passage switching means change paths of the room air and the outside-of-room air. JP-08-210668 discloses a dry type dehumidifying and humidifying device. It comprises a turnable adsorption rotor made of an adsorption material and a rotary drive motor for the rotor and an air fan which sucks indoor air and introduces it into an air passage. Heaters are provided which heat the sucked air, they are on/off controllable. It is the object of the present invention to provide a dehumidified/humidified air supply apparatus having a simple construction, producing little vibration and requiring neither supply nor discharge of water. This object is accomplished in accordance with the features of the independent claims. Dependent claims are directed on preferred embodiments of the invention. When the air of the first set of air passages A is heated by the heating means 5 at the upstream side of the dehumidifying/humidifying means 10, moisture is supplied from the dehumidifying/humidifying means 10 into the air, which means that humidified air is supplied in the first air passage A while the moisture absorption is carried out by the dehumidified dehumidifying/humidifying means 10 in the second air passage B. On the other hand, when the air of the first set of air passages A is not heated by the heating means 5 at the upstream side of the dehumidifying/humidifying means 10, the dehumidifying/humidifying means 10 absorbs the moisture in the air, which means the supply of dehumidified air in the first air passage A and also the dehumidification of the dehumidifying/humidifying means 10 in the second air passage B by actuating the heating means 6 of the second air passage B. The dehumidifying/humidifying means 10 is moved between the portion 10a connected to the first air passage A and the portion 10b connected to the second air passage B, by the driving means 17. When the dehumidified air is supplied by the dehumidifying/humidifying means 10 as described above, the moisture is removed by the air heated by the heating means 6 of the second air passage B, so that no liquid water occurs. When the humidified air is supplied by the dehumidifying/humidifying means 10, the moisture is supplied from the second air passage B, so that it is required to supply liquid water. Further, the invention can be achieved with a simple construction containing only the heating means 5, 6 such as an electric heater, the dehumidifying/humidifying means 10 and the blower 2, and induce little vibration. The dehumidified/humidified air supply apparatus has humidity detection means 30 provided therein. Air in the semiconductor production apparatus is circulated through the first air passage A, and the dehumidified/humidified air supply apparatus further comprises control means for actuating the heating means 5 of the first air passage A and stopping the heating means 6 of the second air passage B, when humidity of an inside of the semiconductor production apparatus is lower than a target humidity, and stopping the heating means 5 of the first air passage A and actuating the heating means 6 of the second air passage B, when the humidity of the inside of the semiconductor production apparatus is higher than the target humidity. The humidity detection means such as a dew point instrument 30 is provided in the semiconductor production apparatus. The air in the semiconductor production apparatus is circulated through the first air passage A. Further, the control means is provided, whereby when the humidity of the inside of the semiconductor production apparatus is lower than the target humidity, that is, humidification is needed, the heating means 5 of the first air passage A is actuated and the heating means 6 of the second air passage B is stopped. Conversely, when the humidity of the inside of the semiconductor production apparatus is higher than the target humidity, that is, dehumidification is needed, the heating means 5 of the first air passage A is stopped and the heating means 6 of the second air passage B is actuated, thereby the air in the semiconductor production apparatus is controlled to have the target humidity. The control means calculates a difference between the humidity of the inside of the semiconductor production apparatus and the target humidity, and in the case where the difference is equal to or less than a predetermined value, controls the heating means 5 of the first air passage A or the heating means 6 of the second air passage B to operate with a power proportional to the difference. The control means may control the heating means 5, 6 of the first air passage A or the second air passage B to operate with a power proportional to the difference when the difference is equal to or lower than the predetermined value, whereby the humidity of the inside of the semiconductor production apparatus is prevented from hunting around the target humidity and it is quickly set to the target humidity. When the difference exceeds the predetermined value, the heating means operates with its one hundred percent power. When the humidity of the inside of the semiconductor production apparatus is lower than the target humidity, the control means calculates a difference between the target humidity and the humidity of the inside of the semiconductor production apparatus, and in the case where the difference is equal to or greater than a predetermined value, the control means may control the air amount of the second air passage B to increase. When the inside of the semiconductor production apparatus is humidified, the difference between the target humidity and the humidity of the inside of the semiconductor production apparatus is calculated. When the difference is equal to or more than the predetermined value, the amount of the air in the second air passage B may be increased. In winter season, the inside of the semiconductor production apparatus is more frequently humidified, and the absolute humidity of the outside air is normally low in winter season. Therefore, when the difference is particularly large, the humidity of the inside of the semiconductor production apparatus can be quickly set to the target humidity by increasing the amount of the air in the second air passage. The dehumidifying/humidifying means may include: a dehumidifying rotor 10 consisiting of a substantially cylindrical base member carrying dehumidifying agent thereon, the dehumidifying rotor 10 having a plurality of air passage holes which are designed in a honey-comb structure in an axial direction thereof; driving means 17 for rotating the dehumidifying rotor 10 around a longitudinal axis thereof; and a partition plate 9 which divides the dehumidifying rotor 10 into a first portion 10a and a second portion 10b in a peripheral direction thereof at both ends of the dehumidifying rotor 10 in the axial direction, and the first air passage A is connected to the first portion 10a while the second air passage B being connected to the second portion 10b. The dehumidifying/humidifying means may have the dehumidifying rotor 10 with a substantially cylindrical overall shape, and the dehumidifying rotor 10 is divided into the first portion 10a and the second portion 10b by the partition plate 9. The first air passage A is connected to the first portion 10a while the second air passage B is connected to the second portion 10b. The dehumidifying rotor 10 is rotated around the axis thereof by the driving means 17, so that the it is moved from the first portion 10a to the second portion 10b or from the second portion 10b to the first portion 10a. Accordingly, when the dehumidification is carried out in the first portion 10a and the dehumidified air is supplied from the first air passage A, the dehumidifying rotor 10 at the first portion 10a gradually absorbs moisture and moves to the second portion 10b. At the second portion 10b, the moisture of the dehumidifying rotor 10 is gradually desorbed by the heated air in the second air passage B. Under the state that the dehumidifying rotor 10 is sufficiently dehumidified, it is moved to the first portion 10a again. When the humidification is carried out in the first portion 10a, the moisture of the dehumidifying rotor 10 at the first portion 10a is gradually desorbed by the heated air, and moves to the second portion 10b. At the second portion 10b, the dehumidifying rotor absorbs the moisture of the non-heated air of the second air passage B, and moves to the first portion 10a again under the state that it sufficiently absorbs the moisture. As described above, uniform dehumidified/humidified air is continuously supplied by the substantially cylindrical dehumidifying rotor 10. The first air passage A and the second air passage B may be connected so as to make parallel flow in the dehumidifying rotor 10. The first air passage A and the second air passage B may be connected to the dehumidifying rotor 10 so as to make parallel flow. Accordingly, the blower 2 can be used commonly to the first air passage A and the second air passage B, and the heating means 5 of the first air passage A and the heating means 6 of the second air passage B can be disposed so as to be adjacent to each other, so that the construction can be simplified. The first air passage A and the second air passage B may be connected so as to make counter flow in the dehumidifying rotor 10. The first air passage A and the second air passage B may be connected to the dehumidifying rotor 10 so as to make the counter flow. Accordingly, the entrance of the second air passage B at which the regeneration of the dehumidifying rotor 10 is most carried out becomes the exit of the first set of air passages A, and the dehumidification/humidification efficiency can be enhanced. Cooling means 21 may be provided at the downstream side of the dehumidifying/humidifying means 10 connected to the first air passage A. The cooling means 21 may be provided at the downstream side of the dehumidifying/humidifying means 10 connected to the first air passage A. When the moisture in the air is adsorbed by the adsorption means such as the dehumidifying rotor 10, an exothermic action is induced. When the moisture adsorbed by the dehumidifying rotor 10 is desorbed, an endothermic action is induced. However, since the heating means such as the electric heater 5 is provided at the upstream side of the dehumidifying/humidifying means such as the dehumidifying rotor 10, the temperature at the exit of the dehumidifying/humidifying apparatus 1 becomes higher than the temperature at the entrance thereof. In order to make the temperature at the exit of the dehumidifying/humidifying apparatus 1 of the first air passage A equal to the temperature at the entrance thereof, the cooling means 21 is provided at the downstream side of the dehumidifying rotor 10 connected to the first air passage A. The cooling means 21 merely reduces the temperature of the circulated air of the first air passage A, and thus a Peltier cooler which is compact and produces little vibration is preferably used as the cooling means. Brief Description of Drawings Other and further objects, features, and advantages of the invention will be more explicit from the following detailed description taken with reference to the drawings wherein: Fig. 1 is a side view showing a dehumidified/humidified air supply apparatus 1 according to a first embodiment of the invention; Fig. 2 is a plan view showing the dehumidified/humidified air supply apparatus 1; Fig. 3 is a systematic diagram showing the dehumidified/humidified air supply apparatus 1; Fig. 4 is a partially enlarged front view of a dehumidifying rotor 10; Fig. 5 is a plan view showing an example of a driving apparatus 17 of the dehumidifying rotor 10; Fig. 6 is a systematic diagram showing a dehumidified/humidified air supply apparatus 1a of a second embodiment of the invention; Fig. 7 is a systematic diagram showing a dehumidified/dehumidified air supply apparatus 1b of a third embodiment of the invention; Fig. 8 is a block diagram showing the electrical construction of the dehumidified/humidified air supply apparatus 1 of the invention; Fig. 9 is a chart showing the relationship between the operation status of electric heaters 5, 6 and the dew point; and Fig. 10 is a systematic diagram showing a dehumidified/humidified air supply apparatus 1c of a fourth embodiment of the invention. Best Mode for Carrying Out the Invention Now referring to the drawings, preferred embodiments of the invention are described below. Fig. 1 is a side view showing the internal construction of a dehumidified/humidified air supply apparatus 1 of an embodiment of the present invention, and Fig. 2 is a plan view and Fig. 3 is a systematic diagram thereof. The air in a semiconductor production apparatus which partially contains outside air is passed from a blower 2 to a pipe line 3 and then fed into the apparatus 1. The upper portion of the apparatus 1 serves as a header 4, and is divided into a first air passage A and a second air passage B. The two air passages A, B are separated from each other by a partition plate 9, and connected through electric heaters 5, 6 to a first portion 10a and a second portion 10b of a dehumidifying rotor 10, respectively. Dehumidified/humidified air is guided from the first portion 10a of the dehumidifying rotor 10 to a supply port 11. The supply port 11 is open to the inside of the semiconductor production apparatus. The second air passage B is guided from the second portion 10b of the dehumidifying rotor 10 to a discharge port 12 and discharged to the outside air. Fig. 4 is a partially enlarged view showing the dehumidifying rotor 10. The dehumidifying rotor 10 has a substantially cylindrical shape as a whole, is composed of a base member carrying dehumidifying agent thereon and has a plurality of gas permeable holes which are designed in a honey-comb structure so as to extend in the axial direction. The dehumidifying rotor 10 may be an activated carbon rotor obtained by impregnating lithium chloride into laminated activated carbon paper, for example, or a silica gel rotor obtained by chemically synthetically coupling silica gel to ceramic fiber paper. When air having high relative humidity is fed to the dehumidifying rotor 10, the moisture of the air is adsorbed by the dehumidifying rotor 10. When air of high temperature is fed, the moisture adsorbed by the dehumidifying rotor 10 is desorbed. The dehumidifying rotor 10 is provided with driving means 17, and the dehumidifying rotor 10 is slowly rotated in the direction as indicated by an arrow 13. The dehumidifying rotor 10 which is humidified or dehumidified by the air of the first air passage A at the first portion 10a of the dehumidifying rotor 10 is moved to the second portion, and dehumidified or humidified by the air of the second air passage B. Fig. 5 is a plan view showing an example of the driving means 17 of the dehumidifying rotor 10. The driving means 17 comprises a driving motor 14, a pulley 15 which is directly linked to the driving motor 17, a belt 16 which is stretched between the pulley 15 and the dehumidifying rotor 10, and tension adjusting means. The tension adjusting means has a supporting point 18 at the center thereof, and it is provided with a tension pulley 19 at one end portion thereof and with a spring 20 at the other end portion thereof, whereby suitable tension is applied to the belt 16 and the driving force of the pulley 15 is transmitted to the dehumidifying rotor 10. For example, when the inside of the semiconductor production apparatus is dehumidified, air of 26°C and 50%RH (absolute humidity:10.5g/kg') is fed to the first air passage A, and then it is supplied as air having absolute humidity of 4.8g/kg' from the supply port 11 into the semiconductor production apparatus. In the second air passage B, the same air is heated up to 75°C and fed to the dehumidifying rotor 10 to dehumidify the dehumidifying rotor 10, and then air of 52°C and absolute humidity of 16.2g/kg' is discharged from the discharge port 12. When the inside of the semiconductor production apparatus is humidified, in the first air passage A, air of 20°C and 40%RH (absolute humidity of 5.8g/kg') is heated up to 70°C and fed to the dehumidifying rotor 10 to be converted to humidified air having absolute humidity of 8.9g/kg', and then supplied from the air supply port 11 into the semiconductor production apparatus. In the second air passage B, the same air is fed to the dehumidifying rotor 10 to give the moisture to the dehumidifying rotor 10, and air having absolute humidity of 2.7g/kg' is discharged from the discharge port 12. A Peltier cooler 21 is provided at the downstream side of the dehumidifying rotor 10 of the first air passage A to cool the air of the first air passage A which is increased in temperature while it is passed through the apparatus 1 so that the temperature thereof is equal to the temperature at the entrance of the apparatus 1. Fig. 6 is a systematic diagram showing a dehumidified/humidified air supply apparatus 1a of a second embodiment of the invention. The apparatus 1a has a similar construction to the apparatus 1, and the same elements are represented by the same reference numerals. In the apparatus 1, the air of the first air passage A and the air of the second air passage B make parallel flow to the dehumidifying rotor 10. However, in the apparatus 1a, they make counter flow. Further, blowers 22, 23 are separately provided to the air passages A, B, respectively. The establishment of the counter flow to the dehumidifying rotor 10 between the first air passage A and the second air passage B provides a higher dehumidification/humidification efficiency, however, the construction thereof is more complicated because the heating heaters 5, 6 are positionally far away from each other and the two blowers 22, 23 are provided. Further, the blowers 22, 23 are separately provided to the air passages A, B respectively, so that the air in the semiconductor production apparatus is perfectly circulated. In the case where it is required to ventilate a part of the air in the semiconductor production apparatus, the outside air is slightly mixed into the first air passage A. In this case, the pressure of the inside of the semiconductor production apparatus is positive, and cleaning air leaks from the gap to the outside. Fig. 7 is a systematic diagram showing a dehumidified/humidified air supply apparatus 1b of a third embodiment of the invention. The apparatus 1b also has a similar construction to the apparatuses 1, 1a, and the same elements are represented by the same reference numerals. In the apparatus 1, the air is fed to the first air passage A and the second air passage B by one blower 2. In the apparatus 1b, the air is separately fed by two blowers 22, 23. Provision of two blowers 22, 23 enables the air in the semiconductor production apparatus to be independently circulated. In the case where it is required to ventilate the air in the semiconductor production apparatus, the outside air is slightly mixed into the first air passage. There may be considered a dehumidifying/humidifying apparatus for feeding the air of the first air passage and the air of the second air passage to the dehumidifying rotor in the counter flow style by using one blower. However, it is not practically used because each air passage is complicated. Fig. 8 is a block diagram showing the electrical construction of the apparatuses 1, 1a, 1b. Humidity detection means, for example, a dew-point instrument 30 is provided in the semiconductor production apparatus. A plurality of dew-point instruments 30 are provided, and the average value thereof may be calculated. A processing circuit 31 which is implemented by a microcomputer or the like compares the output of the dew-point instrument 30 with a target dew point t°C set by the processing circuit 31. When the output of the dew-point instrument 30 (actual dew point) is higher than the target dew point t°C, the electrical heater 6 of the second air passage B is actuated while the electrical heater 5 is not actuated. Accordingly, the air of the first air passage A is dehumidified by the dehumidifying rotor 10, and the dew point of the dew-point instrument 30 is gradually reduced. When the dew point of the dew-point instrument 30 is lower than the target dew point t °C, the electrical heater 6 is stopped by the processing circuit 31, and the electrical heater 5 is actuated. In the case where each of the electrical heaters 5, 6 is subjected to on-off control by the processing circuit, there occurs such a hunting phenomenon that each of the electrical heaters 5, 6 is frequently turned on and off when the dew point in the semiconductor production apparatus approaches to the target dew point t°C and this is unfavorable. Therefore, it is set that both the electrical heaters 5, 6 are not actuated in the range of t±1 °C. Under this control, the dew point is not controlled in the range from t-1°C to t+1°C, and thus precise control cannot be performed. On the other hand, when the difference between the target dew point t°C and the dew point of the dew-point instrument 30 is within a predetermined range, for example, 5°C or less, the electrical heater 5 or 6 is actuated in proportion to the difference between the target dew point t°C and the dew point of the dew-point instrument 30. For example, the electrical heater 5 or 6 is actuated by 100% when the difference between the target dew point t°C and the output of the dew-point instrument is equal to 5°C or more; by 80% when the difference is equal to 4°C; by 60% when the difference is equal to 3°C; by 40% when the difference is equal to 2°C; and by 20% when the difference is equal to 1°C, whereby the humidity of the inside of the semiconductor production apparatus can be precisely controlled. A line L1 of Fig. 9 represents the operation status of the electrical heaters 5, 6 under on-off control, and a line L2 represents the operation status of the electrical heaters 5, 6 under proportional control. Fig. 10 is a systematic diagram showing a dehumidified/humidified air supply apparatus 1c of a fourth embodiment of the invention. The apparatus 1c has a similar construction to the apparatus 1a of the second embodiment, and the same elements are represented by the same reference numerals. In the apparatus 1c, an auxiliary blower 24 is provided to the second air passage B in parallel to the blower 23. In the case where the apparatus 1c is used as a humidified air supply apparatus, for example when the air supplied to the second air passage B is 5°C and 40%RH (absolute humidity of 2.1g/kg'), under such a condition that the outside temperature is low and the absolute humidity is low in winter season or the like, it would be impossible to increase the absolute humidity of the air of the first air passage A by 3g/kg' if the first air passage A and the second air passage B have the same air amount. In this case, the auxiliary blower 24 of the second air passage B is actuated to increase the air amount of the second air passage B. The operation of the auxiliary blower 24 is also carried out by the processing circuit 31 shown in Fig. 8. As a method of increasing the air amount of the second air passage B, the rotational number of the blower 23 may be increased in place of use of the auxiliary blower 24. This embodiment may be applied to the third embodiment shown in Fig. 7. The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and the range of equivalency of the claims are therefore intended to be embraced therein. Industrial Utility As described above, according to the invention, the dehumidified/humidified air is supplied by the first air passage A, and the dehumidifying rotor 10 serving as the dehumidifying/humidifying means is regenerated by the second air passage B. Therefore, the dehumidified/humidified air can be obtained without supplying/discharging water as liquid. Further, the air in the semiconductor production apparatus is not required to be cooled to the dew point or less by the refrigerating machine. Therefore, it is unnecessary to directly installing the refrigerating machine into the semiconductor production apparatus to which the dehumidified/humidified air is to be supplied, no vibration is applied to the semiconductor production apparatus, and the construction can be simplified by the dehumidifying rotor 10, the electrical heaters 5, 6 and the blower 2.

Claims: A dehumidified/humidified air supply apparatus for a semiconductor production apparatus, comprising: air passages (A, B) including heating means (5, 6) disposed at an upstream side thereof, dehumidifying/humidifying means (10) having two portions (10a, 10b) disposed at a downstream side thereof and a blower (2); and driving means (14 - 17) for moving the dehumidifying/humidifying means between the two passages, wherein a first heating means (5) is provided for the first air passage (A) and a second heating means (6) is provided for the second air passage (B), the first air passage (A) is adapted to circulate air from and to said semiconductor production apparatus, and a control means (31) is responsive to a signal from humidity detection means (30) in the semiconductor production apparatus such that it actuates the first heating means (5) of the first air passage (A) and stops the second heating means (6) of the second air passage (B) when humidity detected inside the semiconductor production apparatus is lower than a target humidity, and that it stops the first heating means (5) of the first air passage (A) and actuates the second heating means (6) of the second air passage (B) when humidity detected inside the semiconductor production apparatus is higher than the target humidity, and wherein the control means calculates a difference between the humidity inside the semiconductor production apparatus and the target humidity, and in the case where the difference is equal to or less than a predetermined value, controls the heating means of the first air passage or the heating means of the second air passage to operate in proportion to the difference. The dehumidified/humidified air supply apparatus of claim 1, wherein when the humidity of the inside of the semiconductor production apparatus is lower than the target humidity, the control means calculates a difference between the target humidity and the humidity of the inside of the semiconductor production apparatus, and in the case where the difference is equal to or greater than a predetermined value, the control means controls the air amount of the second air passage to increase. The dehumidified/humidified air supply apparatus of claim 1, wherein the dehumidifying/humidifying means includes: a dehumidifying rotor consisiting of a substantially cylindrical base member carrying dehumidifying agent thereon, the dehumidifying rotor having a plurality of air passage holes which are designed in a honey-comb structure in an axial direction thereof; driving means for rotating the dehumidifying rotor around a longitudinal axis thereof; and a partition plate which divides the dehumidifying rotor into a first portion and a second portion in a peripheral direction thereof at both ends of the dehumidifying rotor in the axial direction, and the first air passage is connected to the first portion while the second air passage being connected to the second portion. The dehumidified/humidified air supply apparatus of claim 3, wherein the first air passage and the second air passage are connected so as to make parallel flow in the dehumidifying rotor. The dehumidified/humidified air supply apparatus of claim 3, wherein the first air passage and the second air passage are respectively connected so as to make counter flow in the dehumidifying rotor. The dehumidified/humidified air supply apparatus of claim 1, further comprising: cooling means disposed at the downstream side of the dehumidifying/humidifying means connected to the first air passage.

Inventors: KAMETANI KEIICHIRO, OTA SHIGEHITO, KAMETANI, KEIICHIRO, OTA, SHIGEHITO, KAMETANI, Keiichiro, Daikin Industries, Ltd, OTA, Shigehito, Daikin Industries, Ltd
Applicants: DAIKIN IND LTD, DAIKIN INDUSTRIES, LTD.
Application year: 1998
Main classification: F24F3
IPC codes: B01D53, H01L21, F24F3