US3696729A

US3696729A - Breather for operating mechanism housing for high voltage switches and the like

Info

Publication number: US3696729A
Application number: US178093A
Authority: US
Inventors: Leonard V Chabala; David M Evans
Original assignee: S&C Electric Co
Current assignee: S&C Electric Co
Priority date: 1971-09-07
Filing date: 1971-09-07
Publication date: 1972-10-10
Anticipated expiration: 1989-10-10
Also published as: GB1387644A; CA931262A; GB1387645A

Abstract

Mechanism housing for out of door high voltage switches which breathe as a result of a change in atmospheric conditions are provided with labyrinths through which the ambient air flows and in which water, airborne corrosive compounds, and dust are trapped, thus preventing them from entering the mechanism housing.

Description

United States Patent Chabala et a1.

1541 BREATIIER FOR OPERATING MECHANISM HOUSING FOR HIGH VOLTAGE SWITCHES AND THE LIKE [72] Inventors: Leonard V. Chabala, Maywood',

IIJaVId M. Evans, Wheeling, both of l [73] Assignee: S dgC Electric Company, Chicago,

22 Filed: Sept. 7, 1971 211 Appl.No.: 178,093

52 us. 01. ..9a/1, 174/16, 174/17, 174/137, 98/29, 98/32, 98 51 51 Int. Cl .1 24:

58 Field of Search ..174/16 R, 17 VA, 187; 98/1, M 98/5 1 29, 32

1 1 Oct. 10, 1972 [56] Reierenoes Cited UNITED STATES PATENTS 873,166 12/1907 Nichols ..174/16 2,302,395 11/1942 Seaman ..174/16 2,741,897 4/1956 Riggins ..98/51 2,859,270 11/1958 Patchin 174/16 Primary Examiner-William J. Wye AttorneyRobert R. Lockwood [57] ABSTRACT Mechanism housing for out of door high voltage switches which breathe as a result of a change in atmospheric conditions are provided with labyrinths through which the ambient air flows and in which water, airborne corrosive compounds, and dust are trapped, thus preventing them from entering the mechanism housing.

PATENTEDBBHOISTZ 3.696.729

SHEET 2 [If 4 26 /25 2 9 PAIENTEDBCI 1 W2 3. 696; 729

sumaura F6 26 ,27 26' 25 27 25 F BREATI-IER FOR OPERATING MECHANISM HOUSING FOR HIGH VOLTAGE SWITCHES AND THE LIKE This invention relates, generally, to high voltage switches for out of door mounting and particularly to the provision of means to permit breathing of the operating mechanism therefor. It has particular relation to breathers for the shunt trip mechanism disclosed in Chabala et al. U.S. Pat. No. 3,508,178, issued Apr. 21, I970, and for the switch operating mechanism disclosed in Bernatt U.S. Pat. No. 3,588,406, issued June 28, l97l.

A housing which serves to enclose and protect mechanical parts of out of door electrical apparatus must preserve the integrity of these parts without maintenance for long periods of time. The function of the housing is to protect the mechanical components from the harmful effects of water, airborne corrosive compounds and dust. Water is objectional on two counts: it can cause several kinds of corrosion; if it freezes in certain areas, it can immobilize mechanical parts. The necessity for protecting the mechanical components from these harmful effects is particularly essential when it is not feasible to use large driving forces, loose mechanical fits and non-precision actions, which would characterize mechanisms that might tolerate water, ice and dirt.

In the past provision has been made for completely sealing the mechanism housing. However, it is difficult to seal such housings in a reliable manner. The reason for this is that there is a number of access openings and shaft extensions which constitute openings that require sealing. If a seal is maintained, there is a difference, generally, in pressure between the air inside the housing and the air outside of it. This pressure differential may be positive or negative and is a function of the air temperature inside the housing and the atmospheric pressure outside of it. Failure of a particular seal in a housing, which is otherwise completely sealed, presents the real possibility that water will be pumped into the housing through the faulty seal when a negative pressure differential is developed.

An alternative to complete this sealing of the mechanism housing is to provide a vent opening which will place the interior of the housing in communication with the atmosphere, thus preventing the creation of differential pressures and reducing greatly the possibility of pumping water into the mechanism housing through an ineffective seal or other small defect. The surface tension of water prevents its entering through small openings provided that no vacuum exists in the mechanism housing. Thus, a simple vent permits pressure equalization. However, some means, such as a filter, is necessary to prevent the entry of dust and insects. Such a filter is likely to become clogged after several years of service. Also there is a possibility that moisture may accumulate in the housing during certain weather conditions.

Among the objects of this invention are: To provide for ventilating the interior of a mechanism housing for a high voltage switch or the like without permitting entrance of water, airborne corrosive compounds and dust into the housing; to allow for the escape of water that might collect in a breather for a mechanism housing; to employ a labyrinth in a housing associated with the mechanism housing through which air flowing into or out of the mechanism housing must pass; to remove extraneous material from such air during its passage through the labyrinth; and to employ labyrinths having generally serpentine or zigzag shaped passageways to provide a relatively long passageway having a relatively small cross section in a relatively small space.

In the drawings:

FIG. 1 is a view, in side elevation, of a high voltage switch embodying this invention, the illustration showing the application of a breather to the operating mechanism housing.

FIG. 2 is a view, in side elevation, from the opposite side shown in FIG. I, and illustrates how the breather of the present invention can be applied to the operating mechanism for the shunt trip.

FIG. 3 is a front plan view of one form of breather that can be employed for venting the mechanism housing shown in FIG. I, the cover having been removed.

FIG. 4 is a rear plan view of the breather shown in FIG. 3.

FIG 5 is a vertical sectional view taken generally along line S-5 of FIG. 3.

FIG. 6 is a view, in side elevation, of the breather shown in FIGS. 3, 4 and 5, certain parts being broken away in order to show details of construction.

FIG. 7 is a view, partly in side elevation and principally in section showing, at an enlarged scale, the details of construction of a vent for the breather housing of the present invention.

FIG. 8 is a view, similar to FIG. 3, and shows a modification of the construction of the labyrinth.

FIG. 9 is a view, in side elevation, of the breather shown in FIG. 8, certain parts being broken away to illustrate the details of construction.

FiG. I0 is a view, similar to FIG. 8 and shows the details of arrangement of the labyrinth for a switch of the type illustrated in FIG. 1 but mounted vertically instead of horizontally.

FIG. 11 is a front plan view of a breather for the shunt trip mechanism illustrated in FIG. 2, the cover having been removed.

FIG. I2 is a vertical sectional view taken generally along line 12-l2 of FIG. 11.

Referring to FIGS. I and 2 of the drawings it will be observed that reference character 10 designates, generally, a high voltage switch of the types referred to in the above patents. It will be understood that this showing is for illustrative purposes and that the present invention can be employed with other mechanism housings that are mounted out of doors and must breathe and accommodate different atmospheric conditions. The switch 10 employs a channel base 11 having upstanding insulators I2 and 13 at its ends. There is an intermediate rotatable insulator 14 which is operated by a linkage 15. At its upper end the rotatable insulator 14 has a mechanism housing 16 mounted thereon which contains various levers, springs, etc. for operating the switch 10 between the closed and open positions. Mounted on one end of the mechanism housing 16 is a current interrupter that is indicated, generally at 17. The current interrupter 17 extends between the mechanism housing 16 and a line terminal 18 which is carried by the upper end of the insulator 12. Also mounted on the mechanism housing 16 is a disconnecting switch blade 19 that is arranged at its distal end to have contact engagement with a stationary switch contact 20 which is mounted on the upper end of the insulator 13 along with a line terminal 21.

The switch may or may not be provided with a shunt trip mechanism. If a shunt trip mechanism is employed, an auxillary insulator 22 is used for mechanically interconnecting the shunt trip mechanism within the mechanism housing 16 and a shunt trip mechanism housing 23, FIG. 2, that is mounted on one side of the channel base 11. As pointed above, it is desirable to permit the mechanism housings l6 and 23 to breathe so as to avoid the necessity for undertaking to seal them completely from the effects of the atmosphere. However, it is undesirable that contaminates and water be permitted to enter the housings l6 and 23. It is to the provision of a breather for the housings l6 and 23 that this invention is particularly addressed.

In FIGS. 3, 4, 5 and 6 one form of a breather is indicated, generally, at 25 for the mechanism housing 16. It comprises a generally rectangular metallic housing, indicated, generally, at 26, which is provided with a lateral flange 27 for application to a side wall of the mechanism housing 16. It will be understood that the metallic housing 26 can be formed as an integral part of the mechanism housing 16. For practical purposes and to permit application of the breather 25 to presently installed switches, it is preferable to form the housing 26 as a separate entity. The housing 26 has a lateral flange 27 which is provided with bolt holes 28 for securing it to the housing 16. As shown more clearly in FIG. 4 and 5, a groove 29 is formed along the inner portion of the lateral flange 27 for receiving an O-ring seal 30. When the lateral flange 27 is bolted securely in place on the mechanism housing 16, the flange 27 is sealed thereto in such manner that moisture cannot enter between it and the mechanism housing 16.

The breather 25 has an integral bottom wall 31 through which a relatively small diameter breather opening 32 extends. It is desirable that only uncontaminated air pass through the breather opening 32 for equalizing the pressure inside the mechanism housing 16 with the atmospheric pressure. For this purpose the housing 26 is provided with a side wall 33. It comprises four sides and encloses a labyrinth that is indicated, generally, at 34 and forms a part thereof. The labyrinth 34 is formed by a flange 35 that may be cast integrally with the bottom wall 31. The inner end 36 of the flange 35 extends around the breather opening 32. The arrangement as such that the flange 35 provides a serpentine passageway 37 having a relatively small cross section. The flange 3S terminates in an up turned end 38 and forms with the adjacent portion of the flange 35 an entrance 39 to the serpentine passageway 37. A cover 41 overlies the outer edges of the flange 35 with a gasket 42 positioned therebetween.

Communication with the atmosphere is provided through openings 44, FIG. 5, in the side wall 33. As shown four openings 44 are employed. The reason for this is to permit draining of moisture that may collect within the housing 26 regardless of the position, either vertically or horizontally, of the switch 10. A vent, indicated generally at 45, is positioned in each of the openings 44.

In FIG. 7 the details of construction of the vent 45 are shown. It will be noted that the vent 45 comprises a tubular metallic fitting 46 having a knurled section 47 to provide for a press fit with the respective opening 44. An annular flange 48 limits the extent that the vent 45 can be pressed into the respective opening 44. The vent 45 has a cylindrical inner surface 49 provided near its outer end with an annular groove 50 in which a screen 51 is positioned. The screen 51 prevents entrance of dust particles, insects etc., into the interior of the housing 26 while permitting the flow of air therethrough.

Provision is made for preventing the entrance of water through the screen 51 in the event that the housing 26 is subjected to flooding such that may occur during a relatively heavy rain storm. For this purpose the fitting 46 is formed with an integral bulbous rim 54 having an annular flat end section 55 intersecting at 56 with the cylindrical inner surface 49. An annular arcuate section 57 is formed intermediate the end section 55 and a cylindrical section 58 which intersects at 59 with an annular plane surface 60 extending at right angles to axis 61 of the vent 45. This construction provides a deep sharp edged groove 62 so that water flow ing over the surface of the vent 45 is forced by this groove to flow around the opening through the vent 45 or to splash away from this opening.

While the breather 25 with the four vents 45 was found to be satisfactory and to accomplish its intended purpose, it was discovered that moisture could condense on the walls of the flange 35 defining the serpentine passageway 37. Because the flange 35 is continuous, such collected water could escape only by evaporation. In those areas where such condensation is likely to occur the construction shown in FIGS. 8 and 9 is preferred.

In FIGS. 8 and 9 essentially the same housing 26 for the breather 25 is employed. Within the side wall 33 there is employed a labyrinth, indicated generally at 65, which employs an inner wall 66 which is spaced from the side wall 33. Interleaved flanges 68 extend from the inner side of the inner wall 66. They are formed integrally with the bottom wall 31 as is the inner wall 66. The inner wall 66 together with the interleaved flanges 68 define a relatively small cross section zigzag passageway 69 between the breather opening 32 in the bottom wall 31 and an entrance 70 to the labyrinth 65.

When the labyrinth is formed as illustrated in FIG. 8 any moisture that condenses on the flanges 68 will flow downwardly through the zigzag passageway 69 and the entrance to the vent 45 It will be understood that the breather 25, constructed as shown in FIGS. 8 and 9, is intended for use on the mechanism housing 16 when the switch end is in the horizontal position shown in FIG. 1. Here only a single vent 45 is required since it will always be located at the bottom of the housing 26.

When the switch 10 is to be mounted in a vertical position the breather, shown generally at 71 in FIG. 10, can be used. The metallic housing 26 is the same as that employed for the breather 25 illustrated in FIG. 8. Within the side wall 33 there is formed a labyrinth that is indicated, generally, at 72. It comprises an inner wall 73 having an entrance 74 at the bottom. Interleaved flanges 75 extending from the inside of the inner wall 73 and from the bottom wall 31 define a relatively small cross section zigzag passageway 76 between the breather opening 32 and the entrance 74.

In the construction shown in FIG. two vents 45 are employed. While only a single vent 45 at the bottom of the breather 71 is required when the switch is installed vertically, the switch 10, prior to installation, may be stored in a horizontal position. In order to insure that any moisture that might collect is discharged when the switch is in the horizontal position, the second or upper vent 45 is provided.

FIGS. 11 and 12 show a breather, indicated generally at 78, for the mechanism housing 23 of the shunt trip mechanism. The breather 78 comprises a metallic housing 79 which is provided with a lateral flange 80 having bolt holes 81 for mounting on the housing 23. A groove 82 is employed for receiving an O-ring seal 83 for the purpose outlined above. The housing 79 has a bottom wall 84 which is provided with a breather opening 85 in the upper left corner. The housing 79 includes a side wall 86 which surrounds a labyrinth that is indicated, generally, at 87. The labyrinth 87 is formed by a series of angularly related spaced pairs of flanges 89-93 which extend from the innerside of the side wall 86 and from an inner wall 94. The flanges 88-93 and the inner wall 94 are preferably cast integrally with the bottom wall 84.

The intersections of the alternate pairs of

flanges

88, 90, and 92 are provided with

openings

88, 90' and 92 for the purpose of placing the adjacent spaces in communication with each other. For this same purpose the

flanges

89, 9i and 93 have openings 8989", 91 '92", and 93'-93" at their ends. An additional opening 94' is provided for the inner wall 94. This construction provides a double zigzag passageway 95 between the breather opening 85 and vents 45 which are located in openings 96 in the wall 86. Since the pairs of flanges 88-93 and the inner wall 94 are attached integrally with the bottom wall 84, it is expedient that the opening, such as the openings 92" in FIG. 12 extend only partially from the distal edges of the pairs of flanges rather than entirely to the bottom wall 84. it will be obvious that this construction provides for the flow of moisture that may condense on the flanges 88-93 since they are inclined for this purpose.

A cover 97, FIG. 12 overlies the side wall 86 and the distal edges of the flanges 88-93 with a gasket 98 therebetween.

The function of the breathers or aerators disclosed herein differs from that of a simple vent in that the long serpentine or zigzag passageways with their extensive surface areas permit some of the water vapor carried by incoming air to condense thereon. This follows from the usual reason for entry of air is due to the breather or aerator housing being cooled by radiation or rain to a temperature less than that of the incoming air. Condensation of some of the water within the housing causes the entering air to be warmer and to contain less water vapor. Conversely, when the

mechanism housing

16 or 23 is warmed again, the drier air being expelled through the breather or aerator will evaporate moisture which previously had condensed on the walls of the passageway. Thus there is an active role taken by the breather or aerator as opposed to the passive role of a simple vent.

We claim:

I. A breather for a mechanism comprising a housing having a bottom wall for mounting on said mechanism and provided with a breather opening for placing the interior of said housing in communication with the interior of said mechanism, a vent in a side wall of said housing placing the interior thereof in communication with the atmosphere, and a labyrinth within said housing interconnecting said breather opening and said vent.

2. The breather according to claim 1 wherein said labyrinth is formed by flange means extending from said bottom wall to an overlying cover forming a part of said housing.

3. The breather according to claim 2 wherein said bottom wall on the side opposite said labyrinth has a gasket containing groove, and a gasket is interposed between said labyrinth and said cover.

4. The breather according to claim 1 wherein said vent comprises a tubular fitting secured at one end to said side wall, provided with a screen across the opening therethrough and having a bulbous rim at the other end whereby rain water flowing over the same tends to flow away from said screen.

5. The breather according to claim 4 wherein said bulbous rim has an annular surface extending from an internal cylindrical surface adjacent said screen to an annular surface in a plane substantially normal to the longitudinal axis of said fitting with an intermediate convex surface.

6. A breather for a mechanism comprising a housing having a bottom wall for mounting on said mechanism and provided with a breather opening for placing the interior of said housing in communication with the interior of said mechanism, a vent in a side wall of said housing placing the interior thereof in communication with the atmosphere, and a labyrinth within said housing interconnecting said breather opening and said vent, said labyrinth being formed by a flange extending at one end partially around said breather opening and around itself a plurality of times thereby defining a circuitous passageway opening at the other end into said housing.

7. The breather according to claim 6 wherein said flange is formed integrally with said bottom wall and extends to an overlying cover forming a part of said housing.

8. The breather according to claim 6 wherein said side wall of said housing has a generally rectangular configuration and a vent is provided in each side.

9. The breather for a mechanism comprising a housing having a bottom wall for mounting on said mechanism and provided with a breather opening for placing the interior of said housing in communication with the interior of said mechanism, a vent in a side wall of said housing placing the interior thereof in communication with the atmosphere, and a labyrinth within said housing interconnecting said breather opening and said vent, said labyrinth being formed by an inner wall spaced inwardly from said side wall, extending around said breather opening at its upper end and having a discharge opening at its lower end, and a plurality of interleaved flanges extending inwardly and downwardly from the inner opposite sides of said inner wall with a distal ends spaced therefrom thereby defining a zigzag passageway between said breather opening and said discharge opening.

10. The breather according to claim 9 wherein said side wall of said housing has a generally rectangular configuration and said vent is located in the lowermost side.

11. The breather for a mechanism comprising a housing having a bottom wall for mounting on said mechanism and provided with a breather opening for placing the interior of said housing in communication with the interior of said mechanism, a vent in a side wall of said housing placing the interior thereof in communication with the atmosphere, and a labyrinth within said housing interconnecting said breather opening and said vent, said labyrinth being formed by a series of angularly related spaced pairs of flanges of increasing length from a first pair partially surrounding said breather opening to a final pair spaced from said side wall, alternate pairs of flanges being at least partially spaced apart at their intersections and at their ends from said side wall of said housing thereby defining a pair of zigzag passageways between said breather opening and said vent, said passageways being joined at the openings between the juxtaposed ends of said flanges.

12. The breather according to claim 11 wherein an inner wall spaced inwardly from said side wall extends from one flange of an intermediate pair of flanges and overlies the ends of the succeeding corresponding flanges of said pairs of flanges.

13. The breather according to claim ll wherein said side wall of said housing has a generally rectangular configuration and said vent is located in the lowermost side.

* I i l

Claims

1. A breather for a mechanism comprising a housing having a bottom wall for mounting on said mechanism and provided with a breather opening for placing the interior of said housing in communication with the interior of said mechanism, a vent in a side wall of said housing placing the interior thereof in communication with the atmosphere, and a labyrinth within said housing interconnecting said breather opening and said vent.

13. The breather according to claim 11 wherein said side wall of said housing has a generally rectangular configuration and said vent is located in the lowermost side.