JP2622058C - - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane gas dryer, and more particularly, to a method in which a steam mixture gas and a dehumidifying purge gas are separated through a hollow fiber membrane composed of a steam permeable membrane. The present invention relates to a film-type gas dryer that discharges a dehumidified gas obtained by flowing and selectively separating water vapor in a steam mixture gas to a dehumidified purge gas side from a dehumidified gas passage. [0002] In recent years, as a dehumidifier for dehumidifying spray air or the like for spraying paint, a membrane air dryer which is a kind of a membrane gas dryer using a water vapor permeable membrane composed of a polymer membrane has been used. It is getting. Such a film-type air dryer is proposed in, for example, Japanese Utility Model Laid-Open No. 3-75821 and Japanese Utility Model Laid-open No. 3-83617. The membrane air dryers proposed in these publications store a hollow fiber bundle in which a large number of hollow fiber membranes made of a polymer water vapor permeable membrane are bundled in a sealed container, and divide the inside of the sealed container into a region within the hollow fiber membrane. A high pressure steam mixed air is supplied to a region inside the hollow fiber membrane, and a low pressure dehumidified purge air is supplied to a region outside the hollow fiber membrane. In such a membrane air dryer, the steam in the steam-mixed air is selectively discharged to the dehumidified purge air side through the hollow fiber membrane based on the steam partial pressure difference between the steam-mixed air and the dehumidified purge air. In addition, it is possible to dehumidify the steam-mixed air. The purge air from which the water vapor has been discharged is discharged outside the sealed container. According to the membrane type air dryer, continuous dehumidification can be performed, and vibration can be eliminated because of the non-movable structure. For this reason, it can be used in a department that refuses to vibrate, such as a semiconductor factory, or in a department where fire is strictly prohibited, such as a coating factory. However, unlike the refrigeration dehumidifier, the membrane air dryer does not generate water droplets during dehumidification, and it is not possible to visually check whether or not dehumidification is performed normally. Further, in general, in a membrane gas dryer, as described above, since dehumidification is performed based on the difference in partial pressure of steam, when a steam mixture gas of extremely high humidity is supplied, or when the membrane is damaged or damaged. When the dryer capacity is reduced due to blockage or the like, the humidity in the obtained dehumidified gas may be higher than a predetermined value. Even in such a case, use without knowing that the obtained dehumidified gas has a humidity equal to or higher than a predetermined value,
It may cause trouble. Further, at the start of the operation of the membrane gas dryer, the obtained dehumidified gas is released or circulated until the humidity becomes equal to or lower than a predetermined value and is dehumidified again. However, the dehumidified gas is released or circulated more than necessary for safety. This is often a problem from the viewpoint of energy saving and resource saving. The above problem can be solved by installing a hygrometer in the dehumidifying gas passage or the dehumidifying gas outlet of the film-type gas dryer so that the humidity of the dehumidifying gas can be directly measured. However, a membrane-type gas dryer equipped with a hygrometer requires an operating power supply for operating the hygrometer in the vicinity, and must be provided with an explosion-proof structure in places where the use of electricity is prohibited in principle, such as strictly prohibited from fire. A membrane gas dryer with a hygrometer cannot be installed. Further, the structure of the membrane gas dryer is complicated by the installation of the hygrometer, so that the membrane gas dryer is expensive. Accordingly, an object of the present invention is to provide a film-type gas dryer that can easily detect the humidity of a dehumidified gas without complicating the structure of the device. Means for Solving the Problems The present inventors have studied to achieve the above object, and as a result, inserted a drying test paper that changes color with humidity fluctuation in the vicinity of a dehumidifying air outlet, and performed a drying test. By observing the degree of discoloration of the paper, it has been found that it is possible to easily determine that the humidity of the dehumidified air is equal to or lower than a predetermined value, and has reached the present invention. That is, the present invention provides a dehumidification method obtained by flowing a steam mixture gas and a dehumidifying purge gas through a hollow fiber membrane composed of a steam permeable membrane, and selectively separating water vapor in the steam mixture gas to a dehumidifying purge gas side. In a film-type gas dryer that discharges gas from a dehumidification gas passage, a small chamber provided in the film-type gas dryer body and a dehumidification gas passage are communicated via a passage having a diameter smaller than the inner diameter of the small chamber, and dehumidification is performed. A humidity display material that changes color according to the humidity of the gas is inserted into the small chamber, and a transparent window is provided in the small chamber so that the humidity display material can be viewed from the outside. In a membrane gas dryer. Also, the present invention provides a dehumidification method obtained by flowing a steam mixture gas and a dehumidification purge gas through a hollow fiber membrane formed of a water vapor permeable membrane, and selectively separating water vapor in the steam mixture gas to a dehumidification purge gas side. In a film-type gas dryer that discharges gas from a dehumidification gas passage, a humidity display material that changes color according to the humidity of the dehumidification gas is inserted into a small chamber provided in the film-type gas dryer body in communication with the dehumidification gas passage. A transparent cap is used in a part of the small chamber, at least a part of which protrudes from the upper surface of the film-type gas dryer body, so that the humidity indicating material in the small chamber can be viewed from outside the side surface of the small chamber. It is also a film-type gas dryer characterized in that: In the present invention, the term "discoloration" means that at least one element of hue, lightness, and saturation changes according to humidity, and the "membrane gas dryer body" refers to a hollow fiber membrane or the like. Refers to the entire casing provided. According to the present invention, according to the present invention, a gas chamber is enclosed in a small chamber provided in a film-type gas dryer main body.
Since the dehumidifying gas from the dehumidifying gas passage comes into contact with the humidity indicating material that changes color depending on the humidity in the dehumidifying gas, and the degree of discoloration of the humidity indicating material can be visually observed from the outside, it is determined whether the humidity of the dehumidifying gas is equal to or lower than a predetermined value. Can be easily determined from the humidity indicating material. Therefore, it is possible to confirm that the membrane gas dryer operates normally without complicating the structure of the membrane gas dryer. Therefore, when the humidity of the dehumidifying gas exceeds a predetermined value, the use of the dehumidifying gas is immediately stopped, and the occurrence of trouble due to the use of the dehumidifying gas having an abnormal humidity can be prevented. Furthermore, even when the operation of the membrane gas dryer is started, when the humidity of the obtained dehumidified gas reaches a predetermined value or less, the use of the dehumidified gas can be started immediately, so that unnecessary release or circulation of the dehumidified gas is required. Energy and resources can be saved. In this case, the small chamber and the dehumidifying gas passage are formed in a passage having a smaller diameter than the inner diameter of the small chamber.
Therefore, because of the connection, the humidity in the small room is controlled by the dehumidified gas passing through the dehumidified gas passage.
Does not fluctuate immediately following the slight fluctuation of humidity. Because of this,
The humidity display material inserted in the room can maintain a stable color tone. On the other hand, a film-type gas
In the event of ear operation or abnormalities (high humidity), the humidity in the small room is
It fluctuates as much as the humidity of the dehumidifying gas fluctuates, and the humidity indicator in the small room changes.
As a result, the use of dehumidifying gas can be immediately started or an abnormality can be dealt with. Furthermore, since the small chamber is connected to the dehumidifying gas passage through a small-diameter passage, the amount of dehumidifying gas flowing into the small chamber is suppressed, and the humidity indicating material is easily kept at a position that is easy to see from the outside.
Be held. In addition, by using a transparent cap that at least partially protrudes from the upper surface of the film-type gas dryer main body as a transparent window forming the small chamber, the humidity display material inserted into the small chamber can be visually observed from outside the side surface of the small chamber. Thus, observation of the degree of discoloration of the humidity indicating material can be further facilitated. The present invention will be described in more detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of a membrane air dryer according to an embodiment of the present invention, in which a supply port 22 for steam-mixed air A and a discharge section 18 for dehumidified air B which is a dehumidified gas passage are formed in a cylindrical container 20. 1 shows a vertical membrane type air dryer 10 arranged linearly on one end side of the air dryer. In FIG. 1, the high-pressure steam-mixed air A supplied to the supply port 22 passes through one end of the steam-mixed air passage 24 in the other end direction, and is then bored in the other end of the steam-mixed air passage 24. Dispersed and discharged from the dispersion holes 25, 25, and reaches one end of a hollow fiber membrane bundle 26 in which a large number of hollow fiber membranes are bundled. In this example, a hollow fiber membrane made of a non-porous fluorine-based separation membrane was used. As described later, low-pressure dehumidified purge air obtained by depressurizing a part of the dehumidified air B flows on the outer peripheral surface of each hollow fiber membrane constituting the hollow fiber membrane bundle 26. For this reason, the steam-mixed air A that has reached one end of the hollow fiber membrane bundle 26 passes through the hollow portion of each hollow fiber membrane toward the other end of the hollow fiber membrane bundle 26, and the steam in the steam-mixed air A is It is selectively separated to the dry purge air side via the hollow fiber membrane and dehumidified. The dehumidified air B passing through each hollow fiber membrane and dehumidified is collected and discharged from the discharge unit 18. [0008] A part of the dehumidified air B collected in the discharge unit 18 passes through the pressure reducing valve 28 and is decompressed to be low-pressure dehumidified purge air. When the dehumidified purge air is depressurized, a temperature drop occurs due to adiabatic expansion, and the relative humidity increases. Therefore, the dehumidified purge air having the increased relative humidity flows through the purge air passage 30 a disposed along the outer peripheral surface of the steam mixed air passage 24, and the heat of the steam mixed air A flowing through the steam mixed air passage 24. Thus, the temperature of the dehumidified purge air is raised to lower the relative humidity. The dehumidified purge air whose relative humidity has been reduced in this way is supplied to the purge air passage 30b.
Flows into the hollow fiber membrane bundle region into which the hollow fiber membrane bundle 26 is inserted through the holes 34, and flows on the outer peripheral surface side of each hollow fiber membrane. At that time, the steam in the steam-mixed air A is selectively discharged through the hollow fiber membrane. The purge air containing water vapor is discharged from the dehumidified purge air outlets 32 to the outside of the membrane gas dryer 10. Since the steam-mixed air A passing through the steam-mixed air passage 24 is cooled by heat exchange with the dehumidified purge air, drain may be generated. Is provided. The main body of the membrane type air dryer 10 of the present embodiment is provided with a small chamber 12 communicating with the discharge unit 18, and a plastic transparent cap 16 is detachably attached to the upper part of the small chamber 12. ing. A humidity test paper 14 as a humidity display material is sealed in the small chamber 12, and the humidity test paper 14 can be visually observed through the transparent cap 16. As the humidity test paper 14, a dryness test paper manufactured by Toyo Roshi Kaisha, Ltd. was used. The humidity test paper 14 changes color with the fluctuation of the air humidity in the small chamber 12, that is, with the fluctuation of the humidity of the dehumidified air B passing through the discharge unit 18, and changes the approximate relative humidity of the dehumidified air B from the outside of the film air dryer 10. You can know. Therefore, by checking the degree of discoloration of the humidity test paper 14, it is possible to easily determine whether or not the dehumidified air B having a predetermined humidity or less is being discharged and to grasp the operation state of the film air dryer 10. Here, the small chamber 12 and the discharge section 18 are connected to a passage 36 having a diameter smaller than the inner diameter of the small chamber 12.
Therefore, the humidity in the small chamber 12 is reduced by the dehumidifying air
It does not fluctuate immediately following the slight fluctuation of the humidity of the air B. For this reason
The humidity test paper 14 inserted into the small chamber 12 can maintain a stable color tone. on the other hand,
When the operation of the membrane type air dryer 10 is started or when there is an abnormality (high humidity), the humidity in the small chamber 12 is reduced.
The degree fluctuates as much as the humidity of the dehumidified air of the discharge section 18 fluctuates.
Immediately after the use of dehumidified air or abnormalities
Can be handled. Further, since the small chamber 12 is connected to the discharge section 18 via the small-diameter passage 36,
The amount of dehumidified air B flowing into the small chamber 12 is suppressed, and the humidity test paper 14 can be easily viewed from outside.
Position easily. In the membrane air dryer 10 shown in FIG. 1, the small chamber 12 formed by the transparent cap 16 is buried except for the upper lid of the transparent cap 16 so that the upper surface of the membrane air dryer is substantially flat. However, the transparent cap 16 may be provided so that the small chamber 12 protrudes from the upper surface of the film-type air dryer main body. Like this
By projecting the transparent cap 16 from the upper surface of the film-type air dryer main body,
The degree of discoloration of the humidity test paper 14 can be visually observed from the outside of the side surface of the transparent cap 16, which makes it even easier to observe the degree of discoloration of the humidity indicating material. In addition, as the humidity test paper 14, a humidity display piece obtained by impregnating a paper piece or a nonwoven fabric piece with cobalt chloride and drying it can also be used. In the embodiment described above, the vertical membrane air dryer in which the supply port for the steam-mixed air and the discharge section for the dehumidified air are arranged linearly at one end of the cylindrical container has been described. However, a supply port for steam-mixed air is provided on one of the end surfaces of the cylindrical container,
Regarding the horizontal membrane type air dryer provided with a discharge section for dehumidified air on the other end face,
It is needless to say that the present invention can be applied. Further, in this embodiment, the membrane air dryer has been described, but the membrane dryer of this embodiment is also applicable to dehumidification of gases other than air, for example, nitrogen gas, carbon dioxide gas, inert gas, freon gas, and the like. Can be used. At this time, it is preferable to use dehumidified air that has been separately dehumidified as the dehumidification purge gas without taking into consideration safety and other issues even if the dehumidification purge gas is discharged outside the film-type gas dryer. According to the present invention, it is possible to know that the humidity of the obtained dehumidified gas is equal to or lower than a predetermined value by using an extremely simple device without using a hygrometer. It is possible to prevent an increase in the production cost and the like of the film-type gas dryer without complicating. In addition, it is possible to easily determine the operation state of the membrane gas dryer, prevent the occurrence of troubles due to operation failure, and, when starting the operation, when the humidity of the obtained dehumidified gas reaches a predetermined value or less, Since the use of the dehumidifying gas can be started immediately, energy saving and resource saving can be achieved.

[Brief description of the drawings]     FIG.   It is a longitudinal section of a membrane type air dryer showing one example of the present invention.     [Explanation of symbols]   10 Membrane air dryer (membrane gas dryer)   12 Komuro   14 Humidity test paper (humidity display material)   16 Transparent cap (lid)   18 Dehumidification air discharge section (dehumidification gas passage)   A steam mixed air (steam mixed gas)   B Dehumidified air (dehumidified gas)

Claims (1)

Claims: 1. A steam mixed gas and a dehumidifying purge gas are flowed through a hollow fiber membrane composed of a steam permeable membrane, and steam in the steam mixed gas is selectively separated to a dehumidifying purge gas side. In the membrane gas dryer that discharges the obtained dehumidified gas from the dehumidified gas passage, the small chamber and the dehumidified gas passage provided in the membrane gas dryer main body are connected via a passage having a smaller diameter than the inner diameter of the small chamber. A transparent window is provided in the small chamber so that the humidity indicating material that is communicated with and changes its color according to the humidity of the dehumidifying gas is inserted into the small room, and the humidity indicating material is visible from the outside. A membrane gas dryer. 2. A transparent window forming the small chamber at least partially from the upper surface of the film-type gas dryer so that the humidity indicating material inserted into the small chamber can be seen from outside the side surface of the small chamber. 2. The film-type gas dryer according to claim 1, wherein a protruding transparent cap is used. 3. A dehumidified gas obtained by flowing a steam mixed gas and a dehumidifying purge gas through a hollow fiber membrane comprising a steam permeable membrane, and selectively separating water vapor in the steam mixed gas to a dehumidifying purge gas side. In a membrane gas dryer that discharges from a dehumidification gas passage, a humidity display material that changes color according to the humidity of the dehumidification gas is inserted into a small chamber provided in the membrane gas dryer main body in communication with the dehumidification gas passage. And, so that the humidity indicator in the small room is also visible from outside the side of the small room,
A membrane gas dryer characterized in that a transparent cap that at least partially protrudes from the upper surface of the membrane gas dryer body is used in a part of the small chamber.