GB2038559A - Vacuum switch - Google Patents
Vacuum switch Download PDFInfo
- Publication number
- GB2038559A GB2038559A GB7941835A GB7941835A GB2038559A GB 2038559 A GB2038559 A GB 2038559A GB 7941835 A GB7941835 A GB 7941835A GB 7941835 A GB7941835 A GB 7941835A GB 2038559 A GB2038559 A GB 2038559A
- Authority
- GB
- United Kingdom
- Prior art keywords
- vacuum switch
- insulating cylinder
- vacuum
- flanges
- coated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229920005989 resin Polymers 0.000 claims abstract description 20
- 239000011347 resin Substances 0.000 claims abstract description 20
- 239000002184 metal Substances 0.000 claims abstract description 15
- 229910052751 metal Inorganic materials 0.000 claims abstract description 15
- 125000005010 perfluoroalkyl group Chemical group 0.000 claims abstract description 3
- 230000002411 adverse Effects 0.000 description 8
- 230000007797 corrosion Effects 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 238000000465 moulding Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 239000003822 epoxy resin Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229920000647 polyepoxide Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000008646 thermal stress Effects 0.000 description 2
- YSGQGNQWBLYHPE-CFUSNLFHSA-N (7r,8r,9s,10r,13s,14s,17s)-17-hydroxy-7,13-dimethyl-2,6,7,8,9,10,11,12,14,15,16,17-dodecahydro-1h-cyclopenta[a]phenanthren-3-one Chemical compound C1C[C@]2(C)[C@@H](O)CC[C@H]2[C@@H]2[C@H](C)CC3=CC(=O)CC[C@@H]3[C@H]21 YSGQGNQWBLYHPE-CFUSNLFHSA-N 0.000 description 1
- 241001052209 Cylinder Species 0.000 description 1
- PYVHTIWHNXTVPF-UHFFFAOYSA-N F.F.F.F.C=C Chemical compound F.F.F.F.C=C PYVHTIWHNXTVPF-UHFFFAOYSA-N 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 150000002118 epoxides Chemical class 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 125000001153 fluoro group Chemical group F* 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- -1 perfluoroalkyl vinyl ether Chemical compound 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
- H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
- H01H33/66—Vacuum switches
- H01H33/662—Housings or protective screens
- H01H33/66207—Specific housing details, e.g. sealing, soldering or brazing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
- H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
- H01H33/66—Vacuum switches
- H01H33/662—Housings or protective screens
- H01H33/66207—Specific housing details, e.g. sealing, soldering or brazing
- H01H2033/66223—Details relating to the sealing of vacuum switch housings
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
- H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
- H01H33/66—Vacuum switches
- H01H33/662—Housings or protective screens
- H01H33/66207—Specific housing details, e.g. sealing, soldering or brazing
- H01H2033/6623—Details relating to the encasing or the outside layers of the vacuum switch housings
Landscapes
- High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
Abstract
A vacuum switch generally comprises an insulating cylinder 1 constituting a vacuum vessel within which relatively movable electrodes are disposed, metal flanges 3 closing both ends of the insulating cylinder, annular metal members 2 for hermetically interconnecting the insulating cylinder and the flanges, and the entire outer surface of the vacuum switch exposed to the surrounding atmosphere is coated with a film 7 of perfluoroalkyl resin. <IMAGE>
Description
SPECIFICATION
Vacuum switches
BACKGROUND OF THE INVENTION
This invention relates to an improved vacuum switch provided with a creeping surface capable of increasing insulation strength and preventing corrosion or degradation of metal portions of the vacuum switch when it is used in wet or contaminated environment.
With recent increase in the demand for vacuum switdhes it has been desired to manufacture a compact vacuum switch having a high insulation strength at low cost and the field of appliation of vacuum switches for use under wet or dirty adverse condition has been widened.
However, the use of the vacuum switch under such adverse condition involves such various problems as lowering of the insulation strength on the creeping surface of an insulating cylinder of the vacuum switch and degradation of the degree of vacuum due to corrosion of metal portions of the vacuum switch.
Fig. 1 shows a prior art vacuum switch which comprises an insulating cylinder 1 constituting a vacuum vessel and made of ceramic or glass. Within the vacuum vessel are disposed relatively movable electrodes. Creeping distance and an insulating cylinder having a smooth surface is generally shorter than that of a corrugated insulating cylinder. For this reason, when the vacuum switch such as shown in Fig. 1 is used under adverse environment, leak discharge often occurs due to increased voltage gradient, and in a especial case of closing or opening a capacitor circuit, the voltage across opposing electrodes increases thereby causing flashover along the creeping surface in the worst case.
In addition, when the vacuum switch is used under the adverse wet or dirty condition, metal portions of the vacuum switch, such as an evacuating pipe 4, upper and lower flanges 3 and welding metals 2, would be corroded. The corrosion of the metal portions lowers the degree of vacuum and causes fatal damage to the vacuum switch, in the worst case.
In order to obviate such defects as described above, in a prior art vacuum switch, an outer corrugated insulating cylinder 5 of a molded resin is disposed to surround the insulating cylinder 1 as shown in Fig. 1. The outer insulating cylinder 5 is provided with a corrugated surface to increase the creeping distance. The outer insulating cylinder 5 is combined with the inner insulating cylinder 1 by direct or indirect molding method. Typical one example of the indirect molding method is shown in Fig. 1, in which a flexible insulating- member 6 is interposed between both insulating cylinders 1 and 5.
When the outer insulating cylinder 5 is directly molded about the inner insulating cylinder 1 it may be broken by thermal stress due to the difference in the thermal expansion coefficients of the materials of the both insulating cylinders at a time when they are molded. Therefore, in order to obviate the above defect it is necessary to carefully select the material and the shape for insulating cylinders 1 and 5. Regarding the indirect molding method performed for removing the defect of the direct molding method, the flexible insulating member 6 is interposed between both insulating cylinders 1 and 5 to alleviate the internal thermal stress, but such flexible member 6 is not mechanically strong and the corrugated insulating cylinder 5 is easily peeled off partially from the intermediate insulating member 6 by impulse force applied at the time of closing or opening the vacuum switch.
SUMMARY OF THE INVENTION
Accordingly, an object of this invention is to provide an improved compact vacuum switch capable of being used in adverse environment.
Another object of this invention is to provide a vacuum switch having an outer surface provided with fluoride resin coating to form a creeping surface for increasing insulatiopn strength and corrosion-proof property.
According to this invention there is provided a vacuum switch of the type comprising an insulating cylinder constituting a vacuum vessel within which relatively movable electrodes are disposed, metal flanges closing upper and lower end openings of the insulating cylinder, and annular metal members for hermetically interconnecting the insulating cylinder and the flanges, wherein the entire outer surface of the insulating cylinder, the flanges, and the annular metal members are coated with a film of a fluororesin.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
Figure 1 shows a longitudinal sectional view of a prior art vacuum switch;
Figure 2 shows a longitudinal sectional view of a vacuum switch according to this invention; and
Figure 3 is a graph showing withstand voltage characteristics of vacuum switches shown in Figs. 1 and 2 used in an extremely adverse environment.
DESCRIPTION OF THE PREFERRED EMBODI
MENT
The vacuum switch shown in Fig. 2 comprises an insulating cylinder 1 constituting a vacuum vessel, flanges 3 closing the upper and lower end openings of the insulating cylinder 1, annual metal members 2 used for hermetically interconnecting the insulating cyl inder 1 and the flanges 3, and an evacuating pipe 4 for evacuating the vacuum vessel. The entire outer surfaces of these members exposed to the surrounding atmosphere are coated with a film of fluororesin 7. For example, perfluoroalkyl resin (PFA resin: hereunder) can be used as the fluororesin 7. The PFA resin is a copolymer of ethylene tetrafluoride and perfluoroalkyl vinyl ether and has the following structure formula,
PFA resin
In the copolymer highly stable fluorine atoms are combined with the carbon atoms.
The PFA resin has excellent thermal stability and chemical stability as well as resistance against adverse environment and corrosion.
Even if liquid drops or moisture adheres the surface of the insulating cylinder coated with a film of PFA resin, the drops are repelled by the film and prevented from gathering together, thus not forming a continuous electrically conductive liquid film on the surface of the PFA resin film. Therefore, the withstand voltage characteristic is extremely improved even if the vacuum switch of this invention is used under adverse condition.
Fig. 3 shows the result of tests for obtaining the withstand voltage characteristics of vacuum switches of the prior art and the present invention when they are used under extremely dirty condition. Curve A represents the withstand voltage characteristic of the prior art vacuum switch, while straight line B shows that of this invention As can be understood from this graph, the vacuum switch of this invention has more excellent withstand voltage characteristic than that of the prior art vacuum switch. Moreover, the PFA resin has excellent corrosion-proof property against all chemicals or materials used for the vacuum switch. In addition, when the vacuum switch is used under wet or dirty condition, corrosion of metal portions of the vacuum switch would be corroded.This problem can be solved by applying the film of the PFA resin to the entire outer surface of the vacuum switch
The film ofthe PFA resin is applied by the steps of degreasing the outer surface of the vacuum switch, cleaning it, spraying a solution of PFA resin, and then baking the coated surface. In this manner, a compact vacuum switch including an insulating cylinder having a thickness of about several hundreds microns is obtained.
The following Table shows results of experiments in which a solution of a mixture of salt and polishing powder was sprayed on the outer surfaces of an epoxide resin coated vacuum switch and PFA resin coated vacuum switch and under this condition voltage was applied across the electrodes disposed in a vacuum vessel.
Table
Flashover Voltage (kV)
Contamination Epoxide
Degree PFA resin resin mg/cm2 Coating Coating 0.03 37.0 15.5 0.12 35.0 14.0 0.35 32.2 8.0
As shown in this Table, the withstand voltage characteristic of the vacuum switch coated with PFA resin according to this invention is more excellent than that of the epoxide resin coatred vacuum switch. In addition, in a case where a silicon grease coated vacuum switch was compared with the PFA resin coated vacuum switch, it was found that the latter had excellent withstand voltage characteristic.
Claims (2)
1. A vacuum switch of the type comprising an insulating cylinder constituting a vacuum vessel within which relatively movable electrodes are disposed, metal flanges closing upper and lower end openings of said insulat-ing cylinder, and annular metal members for hermetically interconnecting said insulating cylinder and said flanges, wherein entire outer surface of said insulating cylinder, said flanges, and said annular metal members are coated with a film of a fluororesin.
2. The vacuum switch according to claim 1 wherein said fluororesin is perfluoroalkyl resin.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15004878A JPS5576523A (en) | 1978-12-06 | 1978-12-06 | Vacuum valve |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2038559A true GB2038559A (en) | 1980-07-23 |
| GB2038559B GB2038559B (en) | 1983-01-06 |
Family
ID=15488359
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7941835A Expired GB2038559B (en) | 1978-12-06 | 1979-12-04 | Vacuum switch |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS5576523A (en) |
| DE (1) | DE2948304C2 (en) |
| GB (1) | GB2038559B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0084238A1 (en) * | 1981-12-19 | 1983-07-27 | Kabushiki Kaisha Meidensha | Vacuum interrupter |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10104904A1 (en) * | 2001-02-03 | 2002-08-08 | Abb Patent Gmbh | Body wrapping process |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1060994A (en) * | 1964-03-06 | 1967-03-08 | Ass Elect Ind | Improvements relating to vacuum switches |
| DE2152527A1 (en) * | 1970-10-26 | 1972-04-27 | Int Standard Electric Corp | Vacuum switch that is actuated by elastic deformation of the housing |
-
1978
- 1978-12-06 JP JP15004878A patent/JPS5576523A/en active Pending
-
1979
- 1979-11-30 DE DE19792948304 patent/DE2948304C2/en not_active Expired
- 1979-12-04 GB GB7941835A patent/GB2038559B/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0084238A1 (en) * | 1981-12-19 | 1983-07-27 | Kabushiki Kaisha Meidensha | Vacuum interrupter |
| US4482790A (en) * | 1981-12-19 | 1984-11-13 | Kabushiki Kaisha Meidensha | Vacuum interrupter |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2038559B (en) | 1983-01-06 |
| JPS5576523A (en) | 1980-06-09 |
| DE2948304C2 (en) | 1982-09-16 |
| DE2948304A1 (en) | 1980-06-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 746 | Register noted 'licences of right' (sect. 46/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |