JPH1128395A - Air gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superior dehumidifying efficiency by setting a membrane type air drier provided with a water vapor permeable membrane permeating selectively water vapor in a compressed air passage formed inside an air gun for jetting compressed air into an object to be jetted such as a work or the like. SOLUTION: An air gun 10 used suitably for removing cuttings or the like adhered on a work or the like is provided with a membrane type air drier 14 on its gun barrel section 12, and compressed air is fed from a compressed air passage 18 formed on a grip section 16 into the air drier 14 through an on-off valve 20, and compressed air dehumidified through the air drier 14 is jetted out of a jet nozzle 23 of a nozzle section 22. The air drier 14 to be used is formed of a hollow fiber membrane bundle 24 composed of a number of bundled hollow fiber membranes permeating water vapor in the compressed air selectively, and both ends of the hollow fiber membrane bundle 24 are fixed by flange sections 26a and 26b with their outer peripheral faces being in contact slidably with the inner wall face of insert holes 28 formed in the gun barrel section 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an air gun,
More specifically, the present invention relates to an air gun for injecting compressed air to an ejection target such as a workpiece.

[0002]

2. Description of the Related Art It is widely used as an air gun for ejecting compressed air ejected from an ejection nozzle to an object to be ejected, such as a workpiece, in order to remove chips, dust, etc. adhered to a workpiece, etc. obtained by machining. I have. The air gun is also used as an air brush for sucking up a liquid such as a paint by compressed air ejected from an ejection nozzle and spraying the liquid onto a spray target. By the way, many workpieces and the like subjected to precision processing dislike water, or if water droplets ejected together with compressed air are mixed into paint, the places where water droplets are mixed remain as traces on the coating film of the object to be ejected, or the finish is finished. Gets worse. For this reason,
A dehumidifier is provided near the compressed air discharge port of the air compressor to dehumidify the compressed air used for the air gun.

[0003]

As described above, by providing the dehumidifier near the compressed air discharge port of the air compressor, water droplets and the like in the compressed air generated by compression and cooling by the air compressor can be removed. . However, in the vicinity of the compressed air discharge port of the air compressor, the temperature of the air that has been heated due to compression may not be sufficiently cooled due to factors such as seasons, and it may be difficult to sufficiently dehumidify. In such a case, the compressed air with insufficient dehumidification is injected from the air gun, which may have an adverse effect on the injection target that injects the compressed air. Further, there is a possibility that the temperature of the compressed air drops in the middle of the compressed air supply pipe from the dehumidifier to the air gun, and water droplets generated by condensation of moisture in the compressed air are ejected from the air gun together with the compressed air. For this reason, the present inventors have attempted to install a simple dehumidifier utilizing centrifugal separation or collision separation in the middle of the compressed air supply pipe. According to the installation of such a simple dehumidifier, it is possible to prevent water droplets generated due to dew condensation or the like from being ejected together with compressed air to an ejection target, but it is difficult to further dehumidify the compressed air. There still remains a possibility that dew condensation may occur due to a decrease in the temperature of the compressed air in the middle of the compressed air supply pipe up to. On the other hand, providing a simple dehumidifying device near the air gun reduces the operability of the air gun. Therefore, an object of the present invention is to provide an air gun capable of injecting sufficiently dehumidified compressed air while maintaining the operability of the air gun.

[0004]

Means for Solving the Problems The present inventors have studied to solve the above-mentioned problems, and as a result, in the middle of a compressed air passage formed in an air gun, water vapor selectively passing through water vapor in compressed air. It has been found that by providing a membrane air dryer having a permeable membrane, sufficiently dehumidified compressed air can be jetted from an air gun, and the present invention has been achieved. That is, the present invention is directed to an air gun for injecting compressed air to an injection target such as a workpiece in a compressed air passage formed inside the air gun. An air gun is provided with a film type air dryer having a film.

In the present invention, as a membrane type air dryer, steam-containing compressed air and dehumidifying purge air are passed through a steam-permeable membrane to selectively separate steam in the steam-containing compressed air to the dehumidifying purge air side. By using a membrane air dryer, the dehumidifying efficiency of the membrane air dryer can be improved. In particular, by using the water vapor permeable membrane as a hollow fiber membrane, the membrane filling rate can be improved, and the size of the membrane air dryer can be reduced. In addition, when the membrane air dryer is provided between the on-off valve for opening and closing the compressed air passage and the injection nozzle, the air gun can have a simple structure. On the other hand, when the membrane air dryer is provided between the compressed air inlet of the compressed air passage and the on-off valve for opening and closing the compressed air passage, the dehumidified purge air is supplied even while the compressed air passage is shut off by the on-off valve. Flow along the water vapor permeable membrane to maintain the dry state of the water vapor permeable membrane, so that even when the shutoff by the open / close valve of the compressed air passage is released and a large amount of water vapor-containing compressed air is supplied to the membrane air dryer, A predetermined dehumidifying performance can be exhibited. By providing a filter for collecting water droplets, dust and the like on the upstream side of the film air dryer, water droplets and rust and other dust in the compressed air can be removed immediately before the film air dryer. Furthermore,
By providing a microfiltration filter having a membrane filter in which micropores are formed on the downstream side of the membrane air dryer, compressed air from which fine particles have been removed can be jetted from an air gun.

According to the present invention, the compressed air immediately before injection is dehumidified by the film air dryer provided in the compressed air passage of the air gun. Therefore, even if the dehumidification of the compressed air supplied to the air gun becomes insufficient due to seasonal factors, etc., the dehumidification is performed by the film-type air dryer provided in the air gun. Can be sprayed from the nozzle. Further, the operability of the air gun is good because the film air dryer is provided in the air gun.

[0007]

FIG. 1 shows an example of an air gun according to the present invention. The air gun 10 shown in FIG. 1 has a barrel 12 provided with a film-type air dryer 14. Compressed air is supplied to the membrane air dryer 14 from a compressed air passage 18 provided in the grip portion 16 via an on-off valve 20, and compressed air dehumidified through the membrane air dryer 14 is supplied to a nozzle. It is injected from the injection nozzle 23 of the part 22. The membrane air dryer 14 used in the air gun 10 shown in FIG. 1 includes a hollow fiber membrane bundle 24 in which a number of hollow fiber membranes that selectively transmit water vapor in compressed air are bundled. Both ends of the hollow fiber membrane bundle 24 are fixed by flange portions 26a and 26b whose outer peripheral surfaces are in sliding contact with the inner wall surface of an insertion hole 28 formed in the barrel portion 12. In the film type air dryer 14, the flange portion 26 a is pressed by the nozzle portion 22 and the insertion hole 28
At a predetermined position.

The hollow fiber membrane constituting the membrane type air dryer 14 dehumidifies the compressed air while selectively allowing water vapor in the compressed air flowing through the hollow portion to pass through the dehumidifying purge air flowing along the outer peripheral surface. . For this reason, air gun 1
A dehumidified air return passage 30 is formed in the wall portion 0 so that a part of the dehumidified air returns to the insertion hole 28 and becomes dehumidified purge air flowing along the outer peripheral surface of the hollow fiber membrane. One end of the dehumidified air return passage 30 is opened on the inner wall surface of the discharge chamber 32 from which the dehumidified air is discharged from the film air dryer 14, and the other end is inserted into the insertion hole 28 located near the flange 26 a. It is open to the inner wall surface. Further, a purge hole 34 penetrating through the wall of the barrel 12 is opened on the inner wall surface of the insertion hole 28 located near the flange 26b. A porous body 36 such as a sponge is attached to the outlet of the purge hole 34 to prevent dust and the like from entering through the purge hole 34 and also serves as a silencer. Therefore, a part of the dehumidified compressed air discharged into the discharge chamber 32 passes through the dehumidified air return passage 30 to the flange portion 2.
Returning to the insertion hole 28 near 6a, the air becomes dehumidified purge air. This dehumidified purge air flows in the countercurrent direction to the compressed air flowing through the hollow portion of the hollow fiber membrane along the outer peripheral surface of the hollow fiber membrane, and absorbs the water vapor selectively permeating the hollow fiber membrane.
The dehumidified purge air having absorbed the water vapor is supplied to the flange 26b.
Is purged to the outside through a purge hole 34 opened in the inner wall surface of the insertion hole 28 located in the vicinity of. As shown in FIG. 2, an orifice 38 is inserted into the dehumidified air return passage 30 to control the amount of dehumidified compressed air returned. The perforated hole for inserting the orifice 38 is plugged with a plug 40 and closed.

The on-off valve 20 provided in the middle of the compressed air passage 18 for supplying the compressed air to the membrane air dryer 14 is integrally formed with the button 42 whose tip projects from the surface of the grip 16. The provided on-off valve body 44 is urged in a direction to close the compressed air passage 18 by a spring 46 as an urging member. For this reason, the spring 4
6, the opening / closing valve body 44 is also pressed against the biasing force of the spring 46 to open the compressed air passage 18 closed by the opening / closing valve body 44. The compressed air is supplied to the membrane air dryer 14.

The compressed air supplied to the membrane air dryer 14 flows through each hollow portion of the hollow fiber membrane of the hollow fiber membrane bundle 24 in the direction from the flange 26b to the flange 26a. The air is permeated by dehumidified purge air flowing in the countercurrent direction with the compressed air along the surface to be dehumidified, and is discharged to the discharge chamber 32. Part of the discharged dehumidified compressed air is
Although the air becomes dehumidified purge air via the dehumidified air return passage 30, most of the dehumidified compressed air is injected from the injection nozzle 23. In this manner, the compressed air injected from the injection nozzle 23 can be sufficiently dehumidified by the film air dryer 14 even if the compressed air supplied to the air gun 10 is insufficiently dehumidified due to seasonal factors or the like. For this reason, compressed air can be safely injected to a workpiece or a coating film subjected to precision processing that dislikes moisture. Further, since the film type air dryer 14 is provided in the air gun 10, the air gun 1
The operability of No. 4 is also good.

The air gun 10 shown in FIG. 1 is provided with only a film type air dryer 14.
In some cases, dust such as water droplets due to dew condensation on the compression supply pipe reaching 0 or rust due to corrosion may be generated. Such water droplets and dust may block the hollow portion of the hollow fiber membrane or the like, or may pass through the hollow fiber membrane and be ejected to the ejection target. For this reason, as shown in FIG. 3, the hollow fiber membrane bundle 24 (FIG. 1) removes water droplets and dust in the compressed air supplied to the membrane air dryer 14 inserted into the case 15, and removes the hollow fiber membrane bundle. A mist filter 50 for removing mist of 0.01 μm or more is installed on the upstream side of the membrane type air dryer 14 in order to prevent clogging of the hollow portion of the mist filter, and dust of 3 μm or more is further installed on the upstream side of the mist filter 50. A line filter 48 to be removed is provided. A filter made of paper or the like is inserted into the line filter 48 in a bent state, and a mist filter 50 is provided.
, A bent filter made of paper or the like and a glass fiber filter are laminated and inserted.

Further, in order to remove ultra-fine dust passing through the hollow fiber membrane of the membrane type air dryer 14, a microfiltration filter 52 for removing dust less than 0.01 μm is installed downstream of the membrane type air dryer 14. I do. The microfiltration filter 52 includes a membrane filter in which micropores are formed,
Synthetic resin hollow fibers having a large number of fine holes formed in a peripheral wall are provided in a bundle. For this reason, the compressed air which flows into the hollow fiber through the micropores and is finely filtered is discharged from the fine filtration filter 52 and is injected from the injection nozzle 23 of the nozzle unit 22. The line filter 48, the mist filter 50, the membrane air dryer 14, and the microfiltration filter 52 are sequentially inserted into the insertion hole 28 from the compressed air supply port side, and the nozzle 22 is screwed into the insertion hole 28. Each filter and the membrane air dryer 14 are fixed at predetermined positions.

In the air gun 10 shown in FIG. 3, the membrane type air dryer 14 is provided with an inlet / outlet and a purge hole 34 of a dehumidified air return passage 30 formed in the barrel 12 and a case 1 thereof.
It is necessary to insert the holes 5 so as to match the openings of the holes. In this regard, the air gun 1 shown in FIG.
In the case of No. 0, each of the line filter 48, the mist filter 50, the membrane air dryer 14, the microfiltration filter 52, and the nozzle unit 22 was modularized, and could be mounted by screwing each other. For this reason, in the membrane air dryer 14, the dehumidified air return passage 30 and the purge holes 34
Is formed on a predetermined wall portion of the case 15, so that the membrane air dryer 14 can be mounted without paying special attention to the positions of the dehumidified air return passage 30, the purge hole 34, and the like.

The air gun 10 shown in FIGS. 1 to 4 is provided with a film type air dryer 14 between the on-off valve 20 and the injection nozzle 23. Therefore, when the compressed air passage is shut off by the on-off valve 20, the compressed air is not supplied to the membrane air dryer 14 and the dehumidified air return passage 3
0, the dehumidified purge air cannot flow along the outer peripheral surface of the hollow fiber membrane. For this reason, if the compressed air passage is shut off for a long time by the on-off valve 20, the drying of the hollow fiber membrane becomes insufficient, and the predetermined time is required until the hollow fiber membrane is dried and sufficient dehumidifying ability is exhibited. Time is needed. In this regard, as shown in FIG. 5, by providing the membrane air dryer 14 between the open / close valve 20 for opening / closing the compressed air passage 18 and the compressed air inlet 54, the compressed air passage 18 is closed by the open / close valve 20. Compressed air is supplied to the film-type air dryer 14 even if it is set. Therefore, the dehumidified air discharged into the discharge chamber 32 is always returned to the membrane air dryer 14 via the dehumidified air return passage 30 opened in the wall of the discharge chamber 32, and the outer peripheral surface of the hollow fiber membrane is removed. The hollow fiber membrane can flow and be kept dry. Therefore, the button unit 4
When the compressed air passage 18 is opened by pressing 2, the dry state of the hollow fiber membrane is maintained, so that sufficient dehumidifying performance can be immediately exhibited, and the dehumidified compressed air can be jetted from the jet nozzle 23. An outlet of a purge hole 34 through which dehumidified purge air is purged is opened at an end surface of the grip portion 16 of the air gun 10 shown in FIG. Grip part 16
This is to prevent the outlet of the purge hole 34 from being blocked by the hand holding the. However, at the outlet of the purge hole 34,
In order to prevent intrusion of dust and the like, a porous body 36 such as a sponge is used.
Is inserted.

However, the air gun 10 shown in FIG.
Since the dehumidifying purge air flows along the outer peripheral surface of the hollow fiber membrane, the amount of dehumidifying purge air is adjusted by the orifice 38 to an amount that can keep the hollow fiber membrane dry. For this reason, when the compressed air passage 18 is opened by pressing the button 42 of the on-off valve 20 and a large amount of compressed air is supplied to the membrane air dryer 14, the amount of dehumidified purge air is insufficient and the injection from the injection nozzle 22 is performed. In some cases, the humidity of the compressed air to be dehumidified tends to vary. In such a case, FIG.
As shown in FIG. 2, one end is opened on the inner wall surface of the compressed air passage 18 through which the dehumidified dehumidified compressed air flows, and the other end is opened and closed by the on-off valve 20.
Dehumidified air return passage 3 bypassing the orifice 38
It is preferable to provide a bypass passage 56 connected to zero. By the bypass passage 56, the on-off valve 2
When 0 is opened and a large amount of compressed air is supplied to the membrane air dryer 14, the dehumidified air is supplied to the dehumidified air return passage 30 via the bypass passage 56, and the dehumidified purge air amount can be supplemented. A check valve 58 for stopping dehumidified compressed air from the orifice 38 toward the compressed air passage 18 and flowing compressed air from the compressed air passage 18 to the dehumidified air return passage 30 is provided in the middle of the bypass passage 56. Have been.

According to the air gun 10 shown in FIG. 6, even when the compressed air passage 18 is closed by the on-off valve 20, the amount is adjusted by the orifice 38 to an amount necessary to keep the hollow fiber membrane in a dry state. The dehumidified air flows along the outer peripheral surface of the hollow fiber membrane via the dehumidified air return passage 30, and keeps the hollow fiber membrane in a dry state. On the other hand, on-off valve 20
When the compressed air passage 18 is opened and a large amount of compressed air is supplied to the membrane air dryer 14, a part of the dehumidified compressed air passing through the on-off valve 20 and the compressed air passage 18 is dehumidified via the bypass passage 56. Dehumidified air supplied to the air return passage 30 as dehumidified air and supplied from the discharge chamber 32 via the orifice 38 can be replenished. For this reason,
A dehumidifying purge air amount corresponding to the amount of compressed air flowing inside the hollow fiber membrane can flow along the outer peripheral surface of the hollow fiber membrane,
The humidity of the dehumidified compressed air discharged from the injection nozzle 22 can be stabilized.

In the air gun of the type shown in FIG. 6, as shown in FIG. 7, the hollow fiber membrane bundle 24 (FIG. 1) is compressed air supplied to the membrane air dryer 14 inserted in the case 15. A mist filter 50 for removing water droplets and dust of 0.01 μm or more is installed on the upstream side of the membrane air dryer 14 in order to remove water droplets and dust of the hollow fiber membrane and to prevent the hollow portion of the hollow fiber membrane from being blocked. A line filter 48 for removing dust of 3 μm or more upstream of the mist filter 50
Is installed. A filter made of paper or the like is bent and inserted into the line filter 48, and a filter made of bent paper or the like and a glass fiber filter are laminated and inserted into the mist filter 50. . The film air dryer 14, the line filter 48, and the mist filter 50 are provided on the grip 16 of the air gun 10.

Further, in order to remove ultra-fine dust passing through the hollow fiber membrane of the membrane type air dryer 14, the barrel 12 has a fine filtration filter 5 for removing dust less than 0.01 μm.
2 is installed. This microfiltration filter 52 is provided with a bundle of synthetic resin hollow fibers having a large number of fine holes formed on the peripheral wall as a membrane filter having fine holes formed therein. For this reason, the compressed air which flows into the hollow fiber through the micropores and is finely filtered is discharged from the microfiltration filter 52,
It is injected from the injection nozzle section 23. In the air gun 10 shown in FIG. 7, the film-type air dryer 14 is connected to the inlet / outlet of the dehumidified air return passage 30 formed in the grip portion 16 and the purge hole 34 and the opening of each hole formed in the case 15. It must be inserted to match.

For this reason, each of the line filter 48, the mist filter 50, the membrane air dryer 14, and the microfiltration filter 52 may be modularized and mounted by screwing each other. Due to such modularization, in the membrane type air dryer 14, since the dehumidified air return passage 30 and the purge hole 34 are formed in a predetermined wall portion of the case 15, special positions are provided at the dehumidified air return passage 30, the purge hole 34, and the like. The membrane air dryer 14 can be mounted without paying careful attention. The air gun shown in FIGS. 1 to 7 uses compressed air ejected from an ejection nozzle to remove an object to be ejected, such as a workpiece, in order to remove chips, dust, and the like attached to a workpiece or the like obtained by machining. Although it is used as an air gun for spraying air, it can also be used for an air brush for sucking up a liquid such as paint by a compressed air jetted from a jet nozzle of the air gun and spraying the liquid onto a spray target.

[0020]

According to the air gun of the present invention, the water vapor in the compressed air is removed by the film air dryer provided in the air gun, and the compressed air is injected from the injection nozzle. For this reason, even if the dehumidification of the compressed air supplied to the air gun becomes insufficient due to seasonal factors or the like, sufficiently dehumidified compressed air can be discharged from the injection nozzle. Furthermore,
Since the film type air dryer is provided in the air gun, the operability of the air gun is good.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of an air gun according to the present invention.

FIG. 2 is an enlarged partial sectional view near an orifice shown in FIG.

FIG. 3 is a partial sectional view showing another example of the air gun of the type shown in FIG.

FIG. 4 is a partial sectional view showing another example of an air gun of the type shown in FIG.

FIG. 5 is a longitudinal sectional view showing another example of the air gun according to the present invention.

6 is a longitudinal sectional view showing another example of the air gun of the type shown in FIG.

FIG. 7 is a longitudinal sectional view showing another example of the air gun of the type shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Air gun 14 Membrane air dryer 18 Compressed air passage 20 On-off valve 22 Nozzle part 23 Injection nozzle 24 Hollow fiber membrane bundle 26a, 26b Flange part 28 Insertion hole 30 Dehumidification air return passage 34 Purge hole 48 Line filter 50 Mist filter 52 Precision filtration Filter 54 Compressed air inlet 56 Bypass passage 58 Check valve

Claims (7)

[Claims] 1. An air gun for injecting compressed air to an object to be ejected such as a workpiece, wherein a water vapor permeable membrane for selectively transmitting water vapor in the compressed air is provided in a compressed air passage formed in the air gun. An air gun comprising a film-type air dryer provided with: 2. A membrane air dryer, in which steam-containing compressed air and dehumidifying purge air are flowed through a steam-permeable membrane to selectively separate steam in the steam-containing compressed air to a dehumidifying purge air side. The air gun according to claim 1, wherein a dryer is used. 3. The water vapor permeable membrane is a hollow fiber membrane.
Or the air gun according to claim 2. 4. The air gun according to claim 1, wherein the membrane air dryer is provided between the on-off valve for opening and closing the compressed air passage and the injection nozzle. 5. The air gun according to claim 1, wherein the membrane air dryer is provided between the compressed air inlet of the compressed air passage and an on-off valve for opening and closing the compressed air passage. 6. A filter for collecting water droplets, dust and the like is provided upstream of the membrane air dryer.
6. The air gun according to any one of the above items 5. 7. The air gun according to claim 1, further comprising a microfiltration filter provided with a membrane filter having fine pores formed downstream of the membrane air dryer.