Device for Preventing Circulation of Liquid Water Entrained in Compressed Air

This invention relates to pneumatic equipment. More particularly, this invention relates to a device for preventing circulation of liquid water entrained in compressed air and represents an improvement in the type of device shown in my U.S. Pat. No. 4,116,650.

It is not unusual for small droplets of water to become entrained in compressed air. If the compressed air is used in paint spraying, such droplets of water can cause imperfections in the paint job. If the compressed air is used to operate pneumatic tools or the like the entrained water can cause damage to parts of the pneumatically operated tools.

An object of this invention is to provide a device for a compressed air line which eliminates entrained water. The device includes a porous plug of fibrous absorbent material through which the compressed air passes and which absorbs the entrained droplets of water and in which is evaporated from the plug as the air passes through the plug after droplets of entrained water have been absorbed.

A further object of this invention is to provide such a device in which the plug is mounted on a hollow screen through which moisture laden air is introduced into the pad to provide a large surface area receiving the moisture laden air.

Briefly, this invention provides a tubular container in a compressed air line through which compressed air passes. A hollow cylindrical screen supports a porous plug of fibrous absorbent material inside the container. The cylindrical screen receives air from the line and the plug receives the air from the cylindrical screen. The plug can be formed of a fabric sheet of cotton gauze or the like rolled with a sheet of screen material which keeps the plug dimensionally stable to form a plug which fits inside the container. Plug supporting members mounted inside the container support the cylindrical screen and the plug. The compressed air passes through the plug so that any entrained droplets of water in the air are absorbed by the gauze of the plug. As more air passes through the plug, absorbed moisture is vaporized into the air to remove the moisture from the plug.

The above and other objects and features of the invention will be apparent to those skilled in the art to which this invention pertains from the following detailed description and the drawings, in which:

FIG. 1 is a perspective view of a compressed air painting system which includes a device for removing entrained water which is constructed in accordance with an embodiment of this invention;

FIG. 2 is a view in side elevation of the device for removing entrained water which is shown in FIG. 1, fragmentary portions of hose sections being shown in association therewith;

FIG. 3 is a view in section taken on an enlarged scale on the line 3--3 in FIG. 2;

FIG. 4 is a view section taken on the line 4--4 in FIG. 3;

FIG. 5 is a view in side elevation of a body member of the device;

FIG. 6 is a view in end elevation of the body member;

FIG. 7 is a view in side elevation of an end closure member of the device;

FIG. 8 is a view in end elevation of the end closure member;

FIG. 9 is a view in side elevation of a first plug support member of the device;

FIG. 10 is a view in end elevation of the first plug support member;

FIG. 11 is a view in side elevation of a second plug support member of the device;

FIG. 12 is a view in end elevation of the second plug support member;

FIG. 13 is a view in section taken on the line 13--13 in FIG. 11;

FIG. 14 is a view in section taken on an enlarged scale on the line 14--14 in FIG. 9;

FIG. 15 is an enlarged fragmentary view of the second plug support member;

FIG. 16 is a view in end elevation of the second plug support member looking in the direction of the arrows 16--16 in FIG. 15;

FIG. 17 is a view in section taken on the line 17--17 in FIG. 11; and

FIG. 18 is a perspective view of an assembly of a fabric strip and a screen element prior to forming into a plug of the device.

In the following detailed description and the drawings, like reference characters indicate like parts.

In FIG. 1 is shown a pneumatically powered paint spraying system which includes a device 10 for removing entrained water which is constructed in accordance with an embodiment of this invention. The device 10 is mounted in a pneumatic line 12 between sections 12A and 12B thereof so that the device is in series between the sections of the pneumatic line. Air is compressed by a compressor 14 and air under pressure is stored in a tank 16. A valve 18 supplies air under pressure from the tank 16 to the pneumatic line 12. The line 12 supplies the air to a paint spray gun 20 after the air has passed through the device 10.

Details of construction of the device 10 are shown in FIGS. 2-18 inclusive. The device 10 includes a tubular casing member of body 22 (FIGS. 4-7 inclusive) and a hollow end closure member 24. The casing 22 has an annular wall 25 defining a central bore or chamber 26. External threads 27 on an end portion of the casing member 22 receive internal threads on the end closure member 24. Internal threads 29 on the body 22 can support a nipple 31 on which the line section 12B is mounted. External threads 35 on the end closure member 24 can support a nipple 37 on which the line section 12A is mounted.

Inside the casing 22 is mounted a plug assembly 28. The plug assembly 28 includes a first plug support member 30 (FIGS. 9 and 10) and a second plug support member 32 (FIGS. 11 and 12). The plug members can be formed of resilient plastic material or the like.

The first plug support member 30 (FIGS. 11 and 12) includes an elongated main tubular portion 33 and a circular head 34 at one end of the main tubular portion 33. The circular head 34 can fit against an internal shoulder 36 in the casing 22, as shown in FIG. 4, with the tubular portion 33 extending along the axis of the casing 22 spaced from the wall 25 thereof. The head 34 fits tightly inside the bore 26 to form a seal therewith. Windows 38 are formed in the circular head 34 to permit fluid to pass therethrough. A bore 40 and a counterbore 42 are provided in the body 33 to form an annular shoulder 44 therein. An end portion 46 of the tubular portion 33 is of reduced external diameter to provide an external shoulder 48 and a cylindrical wall 49 thereon.

The second plug support member 32 (FIGS. 11 and 12) includes a generally circular head 50, an elongated body 52 of cross-shape in section, and a catch portion 54. A short cylindrical section 55 connects the body 52 to the catch portion 54. A shoulder 57 is disposed on the head 50. The head 50 can be received inside a body portion of the end closure member 24 with the shoulder 57 engaging an end wall 58 of the casing member 22 and a portion 60 of the head 50 of reduced diameter fitting inside the casing member 22 so that there is a seal between the head 50 and the interior of the bore 26. The catch portion 54 includess bifurcations 62 which are separated by a slot 64. A cylindrical section 65 of the catch portion connects the bifurcations 62 to the cylindrical section 55. The bifurcations 62 can be compressed to enter the bore 40 so that the bifurcations can be lodged in the counterbore 42 with a shoulder 66 on the bifurcations engaging the shoulder 44 and the cylindrical section 65 engaging the interior of the bore 40 to form a seal therebetween so that the plug support members 30 and 32 are held in assembled relation with outer edges of arms 67 of the body 52 of the second plug support member 32 aligned with the wall 49 of the end portion 46 of the first plug support member 30. A shoulder 101 on the section 55 of the second plug support member 32 can engage an end face 103 of the end portion 46 of the first plug support member 30. A hollow cylindrical screen 68 (FIG. 4) is mounted on the elongated cross-shaped body 52 and on the wall 49 of the end portion 46. The screen 68 can be a fine mesh screen such as a 60 mesh screen and can be formed of material such as stainless steel which is not affected by the compressed air and water which passes therethrough. The screen 68 serves to break up droplets of water in the fluid and to catch any large solid particles which can be carried by the compressed air. Sector shaped openings 70 in the circular head 50 permit fluid in an entry cavity or bore 72 of the end closure member 24 to enter the interior of the cylindrical screen 68. The circular portion 55 disposed between the catch portion 54 and the cross-shaped body 52 closes ends of spaces 70 between the arms 67 of the cross-shaped body 52.

A porous plug 82 is mounted on the cylindrical screen 68 and on the main tubular portion 33 of the first plug support member 30. The plug 82 is formed from a strip 84 (FIG. 18) of fibrous web material such as cotton gauze. A length of screening 86, which can be aluminum window screening or the like, is laid on the web material centrally thereof and the web material is wound on the cylindrical screen 68 and the tubular portion 33 with the screening 86 spirally wound between convolutions of the strip 84 of web material. The plug is held in place between the heads 34 and 50 of the plug support members.

Compressed air from the tank 16 (FIG. 1) is caused to flow through the plug assembly 28. The air along the line section 12A and the nipple 37 and enters the device 10 through the end closure member 24 and passes axially through the openings 70, and radially through the cylindrical screen 68 and into the porous plug 82 when the valve 18 is open, and any droplets of water entrained in the air stream are absorbed by the material of the plug 82, and any fine particles of solid material in the air are caught in the plug 82. The compressed air passes both radially and axially along the plug as the water and fine particles are removed. The air passes through the plug 82 and the windows 38 and leaves the device 10 through the nipple 31 and the line section 12B. As the air continues to pass through the plug, the absorbed water can be evaporated from the material of the web and is discharged as vapor.

The plug assembly 28 can be removed and replaced if necessary.

The device has been described with particular reference to the removal of entrained water from a stream of compressed air, but it can be used in connection with other gas streams such as a stream of vaporized liquified petroleum or propane, or a stream of other gas such as nitrogen, hydrogen, or argon or the like which can carry entrained liquid droplets.

The device which has been described above and illustrated in the drawings is subject to structural modification without departing from the spirit and scope of the appended claims.