JPH09168716A - Dehumidifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an osmotic membrane type dehumidifier which does not require a piping space. SOLUTION: A housing is composed of a receiving cylinder 1 and caps 2, 3, and a large number of hollow fiber membranes 4 of osmotic polymer membranes are bundled up to be received in the housings 1-3. The inside of the hollow fiber membrane 4 is made a high pressure area S1, the peripheral area of the hollow fiber membrane 4 is made a low pressure area S2, and compressed air before dehumidification is supplied to the high pressure area S1 from the outside of the housings 1-3 and discharged outside the housings 1-3. Moreover, between the high pressure area 51 and the low pressure area S2, a purging passage 10a for sending part of the dehumidified air in the high pressure area S1 along the outer surface of the hollow fiber membrane 4 is formed to be integrated into the housings 1-3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dehumidifying device for removing water in compressed air by using a polymer permeable membrane.

[0002]

2. Description of the Related Art A dehumidifying device of this type is disclosed in Japanese Patent Laid-Open No. 62-427.
No. 23 publication. In this device, a large number of hollow fiber membranes made of a polymer permeation membrane are bundled and placed in a sealed container, and the inside of the sealed container is divided into an area inside the hollow fiber membrane and an area outside the hollow fiber membrane, A high-pressure steam mixed gas is supplied to a region outside the hollow fiber membrane, and a dehumidifying gas is supplied into the hollow fiber membrane. Moisture in the water vapor mixed gas permeates into the hollow fiber membrane through the hollow fiber membrane, and the moisture permeated into the hollow fiber membrane is discharged out of the sealed container together with the dehumidifying gas flowing in the hollow fiber membrane. This polymer osmosis membrane system has various advantages such as continuous dehumidification, a long service life due to the long life of the osmosis membrane, and a non-movable structure without noise and vibration.

[0003]

However, since the circuit for supplying dehumidified air for cleaning the moisture that has permeated and separated into the low-pressure region to the low-pressure region is constructed outside the sealed container, piping for that is provided. Must be provided outside the sealed container. Such a pipe outside the sealed container requires an extra installation space other than the dehumidifying device, which is an obstacle to usability of the dehumidifying device.

An object of the present invention is to provide a permeation membrane type dehumidifier which does not require such a piping space.

[0005]

According to the present invention, there is provided:
A large number of hollow fiber membranes made of a polymer permeation membrane are bundled and housed in the housing, and the inside of the hollow fiber membrane serves as a high-pressure area, and the area near the outer surface of the hollow fiber membrane serves as a low-pressure area, and a high-pressure area from outside the housing In addition to supplying compressed air before dehumidification to the outside of the housing, a purge passage for sending a part of the dehumidified air in the high pressure region along the outer surface of the hollow fiber membrane is taken out between the high pressure region and the low pressure region. A dehumidifying device was constructed by being built in the housing.

[0006]

Function: Gaseous water in the compressed air before dehumidification fed into the hollow fiber membrane permeates and separates into the low pressure region through the hollow fiber membrane, and the compressed air delivered from the hollow fiber membrane has extremely low humidity. A part of the dehumidified compressed air is sent to the low pressure region through the purge passage formed in the housing, and the moisture permeated into the low pressure region is scavenged to the outside of the housing. In the structure in which the purge passage for feeding the dehumidified air is incorporated in the housing, the problem of securing an external piping space for purging is solved.

[0007]

【Example】

[First Embodiment] A first embodiment of the present invention will be described below with reference to FIG.

The housing comprises a housing cylinder 1, a supply-side cap 2 fitted to one end of the housing cylinder 1, and a take-out side cap 3 fitted to the other end of the housing cylinder 1. In the storage cylinder 1, a large number of hollow fiber membranes 4 made of a polymer permeation membrane made of polyimide or the like are bundled and stored in an annular shape. Both ends of the bundled hollow fiber membranes 4 are fixed to the inner peripheral surfaces of both ends of the storage cylinder 1 by annular seal members 5 and 6, respectively.
A shield cylinder 7 is erected and fixed between the hollow portions of 6.

A tight stopper 8 is fitted in the lower end opening of the shielding cylinder 7, and the supply region 2a in the supply side cap 2 and the extraction region 3a in the extraction side cap 3 are inside the hollow fiber membrane 4 in the housing. It communicates only through. A region between the storage cylinder 1 and the shield cylinder 7 communicates with the shield cylinder 7 through a plurality of through holes 7 a in the upper portion of the shield cylinder 7, and a plurality of discharge passages L penetrating the storage cylinder 1 and the supply side cap 2.
Communicates with the outside of the housing. That is, the hollow fiber membrane 4, both sealing members 5 and 6, and the tight plug 8 make the inside of the housing a high-pressure region S ₁ consisting of the supply region 2a, the hollow fiber membrane 4 and the take-out region 3a, and the hollow fiber membrane 4 in the storage cylinder 1. It is divided into an outer low pressure region S ₂ . Note that 9
Is a silencer interposed on the discharge passage L ₁ .

A valve seat 10 is fitted into the upper end opening of the shielding cylinder 7, and a needle valve 11 is screwed into the take-out side cap 3 so as to enter the conical passage hole 10a of the valve seat 10. The passage cross-sectional area in the flow path hole 10a can be changed by screwing the needle valve 11.

A net-shaped member 12 and a stopper 13 are interposed in the outlet passage 3b of the take-out side cap 3, and the ball-shaped valve 1 is provided between the net-shaped member 12 and the stopper 13.
4 are accommodated. When there is no upward air flow in the outlet passage 3b, the ball-shaped valve 14 has dropped onto the mesh member 12.

The high-pressure air before dehumidification sent from the inlet 2b of the supply side cap 2 to the supply region 2a is subjected to the permeation separation action of the polymer permeation membrane while passing through the hollow fiber membrane 4. Gaseous water in the air passing through the hollow fiber membrane 4 along the membrane surface is permeated and separated from the hollow fiber membrane 4 into the low-pressure region S ₂ by the permeation separation action of the polymer permeation membrane represented by the following formula. .

Q = ρA (P ₁ · M ₁ −P ₂ · M ₂ ) where Q is the permeation flow rate of water flowing from the hollow fiber membrane 4 to the low pressure region S ₂ , ρ is the permeation rate constant of gaseous water, A is the permeation area of the entire hollow fiber membrane 4, P ₁ is the pressure on the high pressure region S ₁ side, P
₂ is the pressure on the low pressure region S ₂ side, M ₁ is the mole fraction of water on the high pressure region S ₁ side, and M ₂ is the mole fraction of water on the low pressure region S ₂ side. The permeation rate constant ρ of gaseous moisture is several to several hundred times larger than that of oxygen and nitrogen, which are constituent gases of air, and the gaseous moisture preferentially permeates the hollow fiber membrane 4. As a result, the air discharged through the hollow fiber membrane 4 to the take-out region 3a is dehumidified, and most of the dehumidified air is sent out from the outlet passage 3b of the take-out side cap 3 and a part of the dehumidified air is almost in the housing. It is sent to the low-pressure region S ₂ between the storage cylinder 1 and the shield cylinder 7 via the flow path hole 10a provided in the central portion, the inside of the shield cylinder 7, and the through hole 7a.

The dehumidified air passing through the outlet passage 3b pushes up the ball-shaped valve 14, and the upward movement position of the ball-shaped valve 14 restricts the passage sectional area of the outlet passage 3b.
When the ball-shaped valve 14 abuts on the stopper 13, the passing cross-sectional area is the minimum state, so that the flow rate of the dehumidifying air flowing through the outlet passage 3b does not exceed a predetermined amount.
The permeation separation action of water along the membrane surface of the polymer permeation membrane is due to the fact that the permeation rate constant ρ of gaseous water in the above formula is several times to several hundred times larger than that of oxygen and nitrogen which are constituent gases of air. Also, it is affected by the flow velocity of compressed air, and if this flow velocity is high, the permeation separation performance will be reduced. However, due to the interposition of the ball-shaped valve 14 on the outlet passage 3b, the hollow fiber membrane 4
The flow velocity of the compressed air in the inside does not become excessive, and the deterioration of the permeation separation performance is avoided.

The amount of dehumidified air sent to the low pressure region S ₂ between the storage cylinder 1 and the shield cylinder 7 depends on the cross-sectional area of passage in the flow passage hole 10a, and this cross-sectional area of passage is the needle valve 11.
It can be easily adjusted by rotating the. Therefore, the ratio of the dehumidifying air flow rate in the outlet passage 3b (dehumidifying air yield) to the dehumidifying air flow rate sent out from the hollow fiber membrane 4 to the take-out region 3a can be easily adjusted. Needle valve 11 and valve seat 10 that provide such a simple adjustment operation
The purge flow rate adjusting mechanism consisting of the above is incorporated in the housing together with the shield cylinder 7 forming the purge passage, and the purge passage and the mechanism for adjusting the passage cross-sectional area in this passage are installed outside the housing. The simplification and compactness are remarkable, and the problem of installation space in external piping is solved.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIG. Storage cylinder 15, supply-side cap 16 fitted on one end side of the storage cylinder 15, and take-out side cap 17 fitted on the other end side of the storage cylinder 15.
A housing is constituted by and, and a large number of hollow fiber membranes 18 made of a polymer permeation membrane made of polyimide are bundled in a cylindrical shape and housed in the housing cylinder 15. Both ends of the bundled hollow fiber membranes 18 have sealing members 19,
It is fixed to the inner peripheral surfaces of both ends of the storage cylinder 15 by means of 20, and the supply region 16a in the supply-side cap 16 and the extraction region 17a in the extraction-side cap 17 communicate with each other only inside the hollow fiber membrane 18 in the housing. doing. That is, the hollow fiber membrane 18 and the sealing members 19, 20 inside the housing form a high pressure region S ₁ consisting of the supply region 16a, the hollow fiber membrane 18 and the take-out region 17a, and the storage cylinder 15.
It is divided into the low pressure region S ₂ inside the hollow fiber membrane 18 and the outside.

The outlet passage 17 in the take-out side cap 17
A frustoconical flow restriction valve 21 is interposed in the step portion 17c of b, and a through hole 21a is formed in the axial center portion of the flow restriction valve 21.
Is pierced. The flow rate limiting valve 21 is connected to and supported by the step portion 17c by a pressing spring 22, and the outlet passage 17b is provided.
The flow of air inside allows the flow rate limiting valve 21 to be joined to the valve seat surface 17d against the pressing spring 22.

A cover 23 is fitted and fixed from the inner end of the take-out side cap 17 to the storage cylinder 15, and an annular passage L ₂ is formed between the cover 23 and the take-out side cap 17 and the storage cylinder 15. The low-pressure region S ₂ in the storage cylinder 15 is a through hole 15a on the storage cylinder 15.
Through the annular passage L ₂ . Extraction area 1
7a communicates with the annular passage L ₂ via the purge passage 17e, and the needle valve 24 is interposed on the purge passage 17e. The needle valve 24 is the cap 17 on the take-out side.
The passage cross section in the purge passage 17e is adjusted by rotating the needle valve 24.

A cover 25 is fitted and fixed to the end portion of the storage cylinder 15 on the supply side cap 16 side, and an annular discharge passage L ₃ is provided between the cover 25 and the storage cylinder 15 and the supply side cap 16. And an annular silencer 26 is fitted on the outlet side of the discharge passage L ₃ .
The low-pressure area S ₂ in the storage cylinder 15 is
And communicates with the discharge passage L ₃ through the through holes 15a.

The compressed air before dehumidification sent from the inlet 16b of the supply side cap 16 to the supply region 16a is subjected to the permeation separation action of the polymer permeation membrane while passing through the hollow fiber membrane 18, and the gas in the compressed air is removed. Water penetrates and separates into the low-pressure region S ₂ in the storage cylinder 15.

The air discharged to the discharge area 17a through the hollow fiber membrane 18 is dehumidified, and most of this dehumidified air is sent out from the outlet passage 17b of the take-out side cap 17 and a part thereof is purged passage 17e. , Circular passage L ₂
And through the through hole 15a to the low pressure region S ₂ between the inside of the storage cylinder 15.

The dehumidified air passing through the outlet passage 17b pushes up the flow rate restricting valve 21, and when the flow rate of the dehumidifying air in the outlet passage 17b reaches a predetermined amount, the flow rate restricting valve 21 contacts the valve seat surface 17d. As a result, the dehumidified air passes only through the through hole 21a, and the flow rate of the dehumidified air flowing through the outlet passage 17b does not exceed the predetermined amount. Therefore, the flow rate of the compressed air in the hollow fiber membrane 18 does not become excessively high due to the interposition of the flow rate limiting valve 21 on the outlet passage 17b, and the deterioration of the permeation separation performance is avoided.

The amount of dehumidified air sent to the low pressure region S ₂ in the storage cylinder 15 is determined by the passage cross-sectional area of the purge passage hole 17f, and this passage cross-sectional area can be easily adjusted by rotating the needle valve 24. It Therefore, the dehumidified air yield can be easily adjusted as in the first embodiment, and the problem of the installation space in the external pipe can be solved while simplifying the mechanism and making it compact.

[Third Embodiment] Next, a third embodiment of the present invention.
Will be described with reference to FIG. Storage cylinder 27 and storage cylinder
Supply side cap 28 fitted to one end side of 27, and storage
A take-out side cap 29 fitted to the other end of the cylinder 27
The housing is composed of and
Is a large number of polymer permeable membranes such as polyimide
The hollow fiber membranes 30 are bundled and housed in a cylindrical shape. Hollow
Both ends of the thread film 30 are sealed by the seal members 31 and 32.
It is fixed to the inner peripheral surface of both ends of the storage cylinder 27
The supply area 28a in the side cap 28 and the ejection side cap
The take-out area 29a in the housing 29 is inside the housing.
It communicates only through the inside of the hollow fiber membrane 30. That is, hollow fiber
Inside the housing due to the membrane 30 and both sealing members 31, 32
Is the supply area 28a, the inside of the hollow fiber membrane 30 and the take-out area 2
High pressure area S consisting of 9a ₁And inside the storage cylinder 27
Low-pressure region S outside the hollow fiber membrane 30_TwoIs divided into and
You. Then, one of the seal members 32 has an appropriate number of purges.
The orifice 32a has a take-out area 29a and a storage cylinder 27.
Low pressure area S inside_TwoIt is transparently installed so as to communicate with.

An injection passage 33 is provided in the storage cylinder 27 on the side surface of the supply side cap 28, and communicates with the low pressure region S ₂ via the discharge passage L ₄ . A nozzle 34 extends into the injection passage 33, the nozzle 34 communicates with the supply region 28a, and a needle valve 35 is screwed into the nozzle 34. That is, the injection passage 33 and the nozzle 3
An ejector composed of the needle valve 4 and the needle valve 35 is incorporated in the supply side cap 28 constituting the housing.

A silencer 33a is fitted at the outlet of the injection passage 33. Inlet 2 of supply side cap 28
Most of the dehumidified compressed air sent from 8b to the supply region 28a passes through the hollow fiber membrane 30 and is taken out region 29a.
Is reached, and a part is injected from the nozzle 34 to the injection passage 33. This injection pressure can be changed by rotating the needle valve 35. Gaseous water in the air passing through the hollow fiber membrane 30 along the membrane surface is permeated and separated from the hollow fiber membrane 30 into the low-pressure region S ₂ , and the air discharged to the take-out region 29a is dehumidified. Most of this dehumidified air is sent out from the outlet 29b of the take-out side cap 29, and part of it is sent to the low pressure region S ₂ via the purge orifice 32a.

The higher the transmission rate Q is greater than the pressure P ₂ of the permeate flow pressure P ₁ is a low pressure region of the high pressure area S ₁ according to the above formula representing the Q S ₂ increases, the mole fraction of the high-pressure region S ₁ M ₁
There permeation rate Q larger than the mole fraction M ₂ of the low-pressure region S ₂ is increased. Injection of high-pressure air before dehumidification from the nozzle 34 lowers the inside of the low-pressure region S ₂ below atmospheric pressure, and generates a scavenging flow of dehumidified air sent from the purge orifice 32a along the outer surface of the hollow fiber membrane 30. .
Therefore, the gaseous water that has permeated and separated into the low-pressure region S ₂ is carried away to the outside of the housing by the scavenging air of the dehumidifying air through the discharge passage L ₄ , and the pressure in the low-pressure region S ₂ is kept below atmospheric pressure. As a result, the dew point in the low pressure region S ₂ is lowered, whereby the mole fraction M ₂ on the side of the low pressure region S _{2 which} is lower than atmospheric pressure is always suppressed to a low value.

Due to the pressure reducing action of the ejector, the low pressure region S ₂
The inside pressure is reduced below atmospheric pressure and the low pressure area S
_The structure for generating the scavenging air flow in ₂ contributes to the expansion of the pressure difference and the mole fraction difference between the high pressure region and the low pressure region, which greatly influences the permeation flow rate of the gaseous water as expressed by the above equation. As a result, it is possible to increase the permeation flow rate of gaseous moisture while reducing the scavenging flow rate of dehumidified air, and to improve both the permeation separation efficiency and the purging efficiency. Moreover, by incorporating an ejector that uses pre-dehumidification air in the housing, the device can be made compact, and the problem of the installation space in the external piping can be solved.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described with reference to FIGS. Cylindrical housing 3
A support cylinder 37 is fitted into one end of 6 through an annular silencer 38, and a large number of hollow fiber membranes 39 made of a polymer permeation membrane made of polyimide are bundled in a cylindrical shape in the housing 36. It is housed. Bundled hollow fiber membrane 3
Both ends of 9 are fixed to an inlet passage 37a in the support cylinder 37 and an outlet passage 36a at the other end of the housing 36 by seal members 40 and 41. The inlet passage 37a and the outlet passage 36a are inside the housing 36. In the above, the hollow fiber membrane 39 communicates only with the inside. That is, the interior of the housing 36 is divided into a high pressure region S ₁ inside the hollow fiber membrane 39 and a low pressure region S ₂ outside the hollow fiber membrane 39 by the hollow fiber membrane 39 and both sealing members 40 and 41.

The low-pressure region S ₂ communicates with the atmosphere region through the silencer 38 and also communicates with the outlet passage 36a through the purge passage 36b, and the needle valve 42 is provided on the purge passage 36b. There is. Needle valve 42
Is rotatably screwed to the housing 36, and
The servo motor 43, which is operatively connected to the forward / reverse drivable servo motor 43 and constitutes the passage cross-sectional area control mechanism together with the needle valve 42, receives the command control of the microcomputer 45 via the drive circuit 44, and the microcomputer 45 An operation command is output to the servo motor 43 based on the detection signal from the humidity sensor 47 for indexing the dew point via the amplifier circuit 46.

Moisture in the compressed air before dehumidification fed into the hollow fiber membrane 39 from the inlet passage 37a is permeated and separated by the hollow fiber membrane 39 to the low pressure region S ₂ side, dehumidified, and then exit passage 3
It is discharged to 6a. Part of the dehumidified air in the outlet passage 36a is sent to the low pressure region S ₂ from the purge passage 36b, and the moisture in the low pressure region S ₂ is scavenged. The housing 3
Since the inner periphery of 6 is provided with a slight inclination, water does not collect in the low pressure region S ₂ .

The humidity sensor 47 detects the humidity in the supply pipe 48 connected to the outlet passage 36a, and the microcomputer 45 sets the rotational position of the servo motor 43 set according to the detected signal value, that is, the rotational position of the servo motor 43. The operation for obtaining the screwing position of the needle valve 42 is commanded. The servo motor 43 is operated by this operation command, and this operation amount is fed back to the microcomputer 45 via the rotary encoder in the servo motor 43.

When the detected humidity is high, the purge passage 36b
Servo motor 43 in the direction of increasing the passage cross-sectional area in
When the detected humidity is low, the servo motor 43 rotates in the direction of decreasing the passage cross-sectional area of the purge passage 36b. The rotational position of the servo motor 43 corresponding to the detected humidity is obtained from the relationship between the yield of dehumidified air and the atmospheric dew point shown in FIG. Curve C shows the case of a certain pressure of compressed air, for example, when trying to obtain dehumidified air with an atmospheric pressure dew point of −20 ° C.,
When the detected atmospheric pressure dew point, which is detected from the detected humidity, is −20 ° C., the purge passage 36b is used for scavenging approximately 22.5% of the dehumidified air discharged from the hollow fiber membrane 39 to the outlet passage 36a.
Send it to When the detected atmospheric pressure dew point is lower than -20 ° C, the dehumidified air purge amount is less than 22.5%. When the detected atmospheric pressure dew point is higher than -20 ° C, the dehumidified air purge amount is 22%. It should be more than 5%. That is, by feeding back the humidity of the dehumidified air, the dew point of the dehumidified air can be maintained at a constant value, and the quality of the dehumidified air can be stabilized.

Also in the present embodiment having the above-described effects, the purge passage 36 and the needle valve 42 for adjusting the passage cross-sectional area thereof are incorporated in the housing 36, and the apparatus is the same as in the above-mentioned embodiments. The overall compactness and the problem of installation space in external piping are solved.

Incidentally, the humidity sensor 47 in this embodiment.
Alternatively, a pressure sensor may be used. in this case,
The detected pressure is fed back to the operation of the servomotor 43 based on the relationship between the yield of dehumidified air and the atmospheric dew point in FIG. 5, and if the detected pressure is high, the purge amount is reduced,
If it becomes lower, control is performed to increase the purge amount. Thereby, the dew point of the dehumidified air can be maintained at a constant value, and the quality of the dehumidified air can be stabilized. Further, by using the humidity sensor and the pressure sensor in combination, it becomes possible to perform more accurate dew point control.

[Fifth Embodiment] Next, a fifth embodiment of the present invention will be described with reference to FIG. A storage cylinder 49 made of a flexible material such as Teflon or nylon,
Supply side cap 50 fitted to one end side of the storage cylinder 49
And a take-out side cap 51 fitted to the other end of the storage cylinder 49, a housing is formed, and a large number of hollow fiber membranes 52 made of a polymer permeation membrane such as polyimide are provided in the storage cylinder 49. Are bundled and housed in a state of penetrating both caps 50 and 51. As a result, the inlet passage 50a in the supply side cap 50 and the take-out side cap 5
The outlet passage 51a in 1 is the hollow fiber membrane 5 in the housing.
It communicates only through the inside of 2. That is, the hollow fiber membrane 52 and the two caps 50, 51 form a high pressure region S _{1 in the} housing, which comprises the inlet passage 50a, the hollow fiber membrane 52 and the outlet passage 51a, and the low pressure region outside the hollow fiber membrane 52 in the storage cylinder 49. It is set separately for S ₂ .

A screw ring 53 is screwed on the outer periphery of the take-out side cap 51, and an annular passage L ₅ is formed between the outer peripheral stepped portion of the take-out side cap 51 and the inner peripheral stepped portion of the screw ring 53. ing. Annular passage L ₅ represents communicates with the outlet passage 51a and the low pressure area S ₂ via the purge passage 51b, the low pressure region S ₂ communicates with the outside of the housing through a discharge passage 50b in the supply side cap 50.

The compressed air before dehumidification sent from the inlet passage 50a of the supply-side cap 50 to the hollow fiber membrane 52 is subjected to the permeation separation action of the polymer permeation membrane, and the water content of the compressed air is contained in the low pressure region S in the storage cylinder 49. Permeate into ₂ and separate. Hollow fiber membrane 5
The air discharged to the outlet passage 51a through 2 is dehumidified, and a part of the dehumidified air is sent to the low pressure region S ₂ via the purge passage 51b and the annular passage L ₅ . As a result, the water in the low pressure region S ₂ is discharged to the outside of the housing via the discharge passage 50b.

The amount of dehumidified air sent to the low pressure region S ₂ is determined by the passage end area of the annular passage L ₅ , and the passage cross-sectional area is adjusted by the turning operation of the screw ring 53. Therefore, the dehumidified air yield can be easily adjusted, and the problem of the installation space in the external pipe can be solved while simplifying and downsizing the mechanism.

Further, in this embodiment, since the storage cylinder 49 is made of a flexible member, the dehumidifying apparatus as a whole can be curved in a compact shape as shown by a chain line in FIG. 6, for example. As a result, the installation space can be reduced, and the mounting posture can be selected quite freely. Further, it can be used as a part of a piping hose, and can also be used as a rubber hose for free work.

[Sixth Embodiment] Next, a sixth embodiment of the present invention will be described with reference to FIG. Storage cylinder 54, supply side cap 55 fitted on one end side of the storage cylinder 54, and take-out side cap 56 fitted on the other end side of the storage cylinder 54.
A housing is constituted by the above, and a large number of hollow fiber membranes 57 made of a polymer permeation membrane made of polyimide or the like are bundled and housed in an annular shape in the storage cylinder 54. Both ends of the bundled hollow fiber membranes 57 are fixed to inner peripheral surfaces of both ends of the storage cylinder 54 by annular seal members 58 and 59, respectively, and between the hollow portions of the annular seal members 58 and 59. The shield cylinder 60 is fixedly installed.

A tight stopper 61 is fitted in one end opening of the shielding cylinder 60, and a supply region 55 in a supply side cap 55 is provided.
In the housing, a and the take-out area 56a in the take-out side cap 56 communicate with each other only through the hollow fiber membrane 57. The area between the storage cylinder 54 and the shield cylinder 60 is covered by the plurality of through holes 60 a on the other end side of the shield cylinder 60.
0, and communicates with the outside of the housing through a through hole 54a in the lower part of the storage cylinder 54. That is, the hollow fiber membrane 5
7, a high pressure region S ₁ consisting of a supply region 55a, a hollow fiber membrane 57 inside and a take-out region 56a inside the housing by both seal members 58, 59 and a sealing plug 61, and a low pressure region S outside the hollow fiber membrane 57 inside the storage cylinder 54. It is divided into ₂ and. The compressed air before dehumidification is sent into the hollow fiber membrane 57 from the supply region 55a, dehumidified and sent out to the discharge passage 55a.

An electropneumatic converter 62 is connected to the outer end of the take-out side cap 56, and a purge passage 62a passing through a nozzle 63 therein communicates with the discharge area 56a via an outlet passage 62b. The purge passage 62a communicates with the inside of the shielding cylinder 60 through the communication cylinder 64, and a part of the dehumidified air sent from the discharge area 56a to the outlet passage 62b is in the purge passage 62a and the shielding cylinder 60 and the through hole 60.
It is sent to the low pressure region S ₂ via a. Nozzle 63
A flapper 65 made of a piezoelectric element plate is extendedly arranged in the vicinity of the ejection port of the flapper 65, and the flapper 65 is curvedly displaced in accordance with the voltage value applied to the flapper 65 from the control unit 66. The injection flow rate is controlled.

The humidity sensor 6 is provided inside the lower part of the storage cylinder 54.
7 is attached, and this detection signal is sent to the control unit 66. The control unit 66 calculates the applied voltage to the flapper 65 based on this detection signal, and applies this calculated applied voltage to the flapper 65. When the detected humidity is higher than the set humidity, the control unit 66 applies a low voltage to the flapper 65, and the bending amount of the flapper 65 can be suppressed low. As a result, the amount of dehumidified air jetted from the nozzle 63 increases, and the moisture scavenging action in the low pressure region S ₂ is enhanced.
Therefore, the difference between the mole fraction M ₁ of water inside the hollow fiber membrane 57 and the mole fraction M ₂ outside the hollow fiber membrane 57 becomes large, and dehumidification of the compressed air is promoted. When the detected humidity is low, the control unit 6
6 applies a high voltage to the flapper 65, and the flapper 65 bends greatly. As a result, the injection amount of dehumidified air from the nozzle 63 is reduced, and the moisture scavenging action in the low pressure region S ₂ is suppressed. Therefore, the difference between the mole fraction M ₁ of water inside the hollow fiber membrane 57 and the mole fraction M ₂ outside the hollow fiber membrane 57 becomes small, and dehumidification of the compressed air is suppressed. That is, the low pressure region S
The dew point of the dehumidified air can be kept constant by detecting the amount of water that permeates and separates into ₂ .

By incorporating the purge passage 62a for performing such dew point control and the nozzle flapper mechanism for adjusting the passage cross-sectional area of the purge passage 62a in the housing, the mechanism can be simplified and made compact, while the external structure is improved. It is possible to solve the problem of installation space in piping.

[Seventh Embodiment] Next, a seventh embodiment of the present invention will be described with reference to FIG. This embodiment has the same configuration as that of the sixth embodiment except that the flow rate sensor 68 is provided on the outlet passage 62b instead of the humidity sensor. The same members as those of the sixth embodiment are designated by the same reference numerals. , Its detailed description is omitted. The detection signal from the flow rate sensor 68 is the control unit 66.
Then, the control unit 66 calculates a voltage value according to the detected flow rate value and applies it to the flapper 65. When the detected flow rate is higher than the set flow rate, the control unit 66 applies a low voltage to the flapper 65, and the bending amount of the flapper 65 can be suppressed low. This increases the amount of dehumidified air ejected from the nozzle 63,
The water scavenging action in the low pressure region S ₂ is enhanced. When the detected flow rate is small, the control unit 66 applies a high voltage to the flapper 65, and the flapper 65 bends greatly. As a result, the injection amount of dehumidified air from the nozzle 63 is reduced, and the moisture scavenging action in the low pressure region S ₂ is suppressed. That is, the dew point of the dehumidified air can be kept constant by detecting the flow rate of the dehumidified air in the outlet passage 62b.

[Eighth Embodiment] Next, an eighth embodiment of the present invention will be described with reference to FIG. In this embodiment, a needle valve 72 is blocked at the tip of a common piston rod 71 of a large-diameter piston 69 housed in a large-diameter control pressure chamber R ₁ and a small-diameter piston 70 housed in a small-diameter control pressure chamber R _2. Cylinder 60
It is fixed so as to face the seating surface 60b of one of the openings, and a full-pressure extraction pipe 73 and a static-pressure extraction pipe 74 project from the outlet passage 62b. The full-pressure take-out pipe 73 is in communication with the control pressure chamber R ₁ , and the static pressure take-out pipe 74 is in communication with the control pressure chamber R ₂ . Then, the pressure spring 75 is provided in the control pressure chamber R ₂ with the small diameter piston 7
It is housed so that 0 is pushed down.

The total pressure due to the dehumidified air flow in the outlet passage 62b is transmitted to the control pressure chamber R ₁ through the total pressure extraction pipe 73, and the static pressure is transmitted through the static pressure extraction pipe 74.
Transfer to ₂ . The difference between total pressure and static pressure is the difference between both pistons 69, 7
When the flow velocity in the outlet passage 62b increases, the piston is pushed up against the pressing spring 75, the needle valve 72 separates from the seat surface 60b, and when the flow velocity decreases, the piston is pushed by the pressing spring 75. Is pushed down and the needle valve 72 approaches the seat surface 60b. As a result, the purge flow rate of the dehumidified air is controlled, and dehumidified air with a constant dew point can be obtained.

[Ninth Embodiment] A ninth embodiment of the present invention will now be described with reference to FIG. A supply side cap 80 and a take-out side cap 81 are fitted to both ends of a storage cylinder 79 that accommodates a hollow fiber membrane 78 made of a polymer permeation membrane bundled by seal members 76 and 77. A needle valve 82 is interposed on the purge passage 81a. Purged from the extraction area 81b in the extraction side cap 81 which is a part of the high pressure region S ₁ passage 8
The dehumidified air flowing into 1a scavenges the low pressure region S ₂ and flows out from the through hole 79a on the storage cylinder 79.

In the present embodiment, in which the purging passage 81a and the needle valve 82 are incorporated to simplify the mechanism and reduce the size of the mechanism, and the problem of the installation space in the external pipe is solved, the supply side cap 80 and the take-out side cap 81 have outer circumferences. Mounting flanges 80a and 81c are provided, and mounting flanges 80a and 81c are provided with mounting holes 80b and 81d through which bolts are inserted. The installation flange portions 80a and 81c simplify the installation of the dehumidifier itself, and can be handled in the same manner as piping.

[0051]

As described above in detail, the present invention is a purge for sending a part of dehumidified air along the outer surface of a large number of hollow fiber membranes made of a polymer permeable membrane which are bundled and housed in a housing. Since the passage is built in the housing, it is not necessary to provide a pipe for the purge passage outside the dehumidifier, which greatly simplifies and downsizes the mechanism and solves the problem of installation space in the external pipe.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a first embodiment embodying the present invention.

FIG. 2 is a side sectional view showing a second embodiment.

FIG. 3 is a side sectional view showing a third embodiment.

FIG. 4 is a side sectional view showing a fourth embodiment.

FIG. 5 is a graph showing the relationship between dehumidified air yield and atmospheric pressure dew point.

FIG. 6 is a side sectional view showing a fifth embodiment.

FIG. 7 is a side sectional view showing a sixth embodiment.

FIG. 8 is a side sectional view showing a seventh embodiment.

FIG. 9 is a side sectional view showing an eighth embodiment.

FIG. 10 is a side sectional view showing a ninth embodiment.

[Explanation of symbols]

The housing cylinder 1 and the caps 2 and 3, which form the housing of the first embodiment, the hollow fiber membrane 4, and the flow passage hole 10a which forms the purge passage. Storage cylinder 1 constituting the housing of the second embodiment
5 and caps 16 and 17, hollow fiber membranes 18, purge passages 17e and 17f. A housing cylinder 27, caps 28 and 29, a hollow fiber membrane 30, and a purge orifice 32a which constitute the housing of the third embodiment. The housing 36 of the fourth embodiment,
The purge passage 36b and the hollow fiber membrane 39. A storage cylinder 49 and caps 50, 51 that form the housing of the fifth embodiment,
The purge passage 51a and the hollow fiber membrane 52. A storage cylinder 54 and caps 55, 56 that form the housing of the sixth embodiment,
Hollow fiber membrane 57, purge passage 62a. A storage cylinder 79 and caps 80, 81 that form the housing of the ninth embodiment,
Hollow fiber membrane 78, purge passage 81a.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuyoshi Hanazawa 3005 Hayasaki, Kita Sotoyama, Komaki City, Aichi Prefecture C-Kedi Co., Ltd. Within the corporation

Claims (6)

[Claims] 1. A large number of hollow fiber membranes made of a polymer permeation membrane are bundled and housed in a housing, and the inside of the hollow fiber membrane serves as a high pressure region, and the region near the outer surface of the hollow fiber membrane serves as a low pressure region. Compressed air before dehumidification is supplied from the outside of the housing to the high pressure region, is taken out of the housing, and a part of the dehumidified air in the high pressure region is sent along the outer surface of the hollow fiber membrane between the high pressure region and the low pressure region. A dehumidifying device characterized in that a purging passage for the above is formed in a housing. 2. The dehumidifying device according to claim 1, wherein the purge passage is formed so as to be incorporated substantially in the center of the housing. 3. The dehumidifying device according to claim 1, further comprising a flow rate control valve disposed on the outlet passage of the dehumidified compressed air, the flow rate control valve being displaced by the flow rate. 4. The dehumidifying device according to claim 1, wherein a decompression mechanism for decompressing a low pressure region is incorporated in the housing. 5. The dehumidifier according to claim 1, wherein a passage cross-section area control mechanism is interposed on the purge passage, and the passage cross-section area control mechanism is operated and controlled based on the detection result of the dew point indexing sensor. 6. The dehumidifying device according to claim 1, wherein a cylindrical member that surrounds a side surface of the bundled hollow fiber membranes to form a housing is formed of a flexible member.