GB1603765A – Polytetrafluoroethylene-coated glass electrical insulator
– Google Patents
GB1603765A – Polytetrafluoroethylene-coated glass electrical insulator
– Google Patents
Polytetrafluoroethylene-coated glass electrical insulator
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Publication number
GB1603765A
GB1603765A
GB2175878A
GB2175878A
GB1603765A
GB 1603765 A
GB1603765 A
GB 1603765A
GB 2175878 A
GB2175878 A
GB 2175878A
GB 2175878 A
GB2175878 A
GB 2175878A
GB 1603765 A
GB1603765 A
GB 1603765A
Authority
GB
United Kingdom
Prior art keywords
ptfe
polytetrafluoroethylene
insulator
film
electric
Prior art date
1977-05-24
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.)
Expired
Application number
GB2175878A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fidenza Vetraria SpA SA
Original Assignee
Fidenza Vetraria SpA SA
Priority date (The priority date 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 date listed.)
1977-05-24
Filing date
1978-05-24
Publication date
1981-11-25
1978-05-24
Application filed by Fidenza Vetraria SpA SA
filed
Critical
Fidenza Vetraria SpA SA
1981-11-25
Publication of GB1603765A
publication
Critical
patent/GB1603765A/en
Status
Expired
legal-status
Critical
Current
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Classifications
H—ELECTRICITY
H01—ELECTRIC ELEMENTS
H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
H01B17/00—Insulators or insulating bodies characterised by their form
H01B17/50—Insulators or insulating bodies characterised by their form with surfaces specially treated for preserving insulating properties, e.g. for protection against moisture, dirt, or the like
H—ELECTRICITY
H01—ELECTRIC ELEMENTS
H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
H01B19/00—Apparatus or processes specially adapted for manufacturing insulators or insulating bodies
H01B19/04—Treating the surfaces, e.g. applying coatings
Description
(54) POLYTETRAFLUOROETHYLENE-COATED, GLASS
ELECTRICAL INSULATOR
(71) We, FIDENZA VETRARIA
S.P.A., an Italian Company of 31 Foro Buonaparte, Milan, Italy, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an electrical insulator made of glass and coated with polytetrafluoroethylene, for use with high-voltage electric lines.
As is known, one of the essential features required of electric insulators, and especially of insulators to be used on high voltage lines, is that of maintaining the insulation under the most adverse conditions, in particular under conditions of atmospheric pollution, no matter whether originated from the sea (brackishness or salinity) or from industry in general.
To this end use is often made of insulators exhibiting a particularly extended creeping line. The term «creeping line» means the path of an electric discharge over a surface between a live electrode and earth (i.e. between a live electrode and any part of the supporting structure having the same potential as the earth).
A creeping line is sufficiently extended when the ratio of said line to the straight line distance between a live electrode and earth (as defined hereinabove) is at least equal to, or preferably higher than, 3.
Certain insulators of this type have a particular profile specially designed to obtain an extended creeping line, and these are called salt-proof or fog-proof insulators.
It has been found, however, that such contrivance is not sufficient to achieve safe insulation of the electric line under all weather conditions, because not only the profile but also the material which the insulator is made of both significantly affect the performances of the insulator.
For this reason insulators manufactured from various materials have been tested and, among these, excellent performances have been supplied by insulators consisting of a supporting bar made of resin-bonded glass-fibre on which a finned covering (or, more exactly, a finned structure) of Polytetrafluoroethylene (PTFE) had been applied.
Insulators of this type, however, exhibit a few drawbacks from the viewpoint of both manufacture and electromechanical behaviour, such drawbacks depending on the difference existing between the chemical-physical characteristics of the supporting bar of resin-bonded glass-fibre and those of the PTFE finned covering (or structure).
Thus, it is an object of embodiments of the present invention to obtain salt-proof or fogproof electric insulators of safe performance, exhibiting neither the manufacturing drawbacks nor those regarding the electromechanical behaviour found in the insulators of the prior art.
Another object is that of obtaining salt-proof or fog-proof electric insulators of very simple manufacture and sufficiently moderate cost with respect to the insulators of the prior art.
The present invention provides an electric insulator for insulating high voltage electric lines, which comprises an insulator body of tempered or annealed glass coated over its entire surface with a film of polytetrafluoroethylene (PTFE).
In this way the good results in operation already given by glass insulators are further improved and very considerably increased by virtue of the polytetrafluoroethylene coating applied over the entire free glass surface.
The coating is preferably obtained by acting on the glass insulator as follows:
a) the dielectric (glass insulator body) is subjected to sandblasting by means of a granular abrasive of suitable characteristics;
b) the insulator body is coated, either by spraying or dipping, in order to form an undercoat (the so-called «primer», or first coat) based on PTFE;
c) the undercoat is subjected to baking at a temperature of about 400 C; d) the insulator is coated again, by spraying or dipping, in order to cause a fine dispersion of PTFE to deposit onto the whole insulator surface, such dispersion constituting the second, and final, coat of the polytetrafluoroethylene coating;;
e) finally, further baking of the insulator and, in particular, of the double layer of
PTFE deposited on its entire surface, is carried out again at a temperature of about 4o00C.
At the conclusion of such operations the insulator body has been completely coated with a PTFE film having a thickness of some tens of ym; more precisely, the film preferably exhibits a thickness ranging from 10 to 80 pm, more preferably from 30 to 40 sm.
The PTFE coating of glass insulators has allowed, as mentioned hereinbefore, a substantial improvement in the behaviour and performance of such insulators to be achieved in operation under conditions of atmospheric pollution. Such improvement was clearly demonstrated in artificial pollution tests which the PTFE-coated insulators were subjected to.
It was possible to ascertain an improvement by more than two points, or grades, in the logarithmic scale of salinity, relative to the results obtained from the same uncoated insulator body, in the artificial pollution tests carried out according to the salt spray fog method (C.E.I. standards — Supplements S.
487).
WHAT WE CLAIM IS:
1. An electric insulator for insulating high voltage electric lines, which comprises an insulator body of tempered or annealed glass coated over its entire surface with a film of polytetrafluoroethylene (PTFE).
2. An electric insulator according to claim 1, prepared by sandblasting the surface of the insulator body, coating the entire surface with a thin film of PTFE, baking at substantially 400″C, applying a further coating of PTFE, and baking again at substantially 400 C.
3. An electric insulator according to claim 1 or 2, wherein the polytetrafluoroethylene (PTFE) film is deposited by spray painting the insulator body.
4. An electric insulator according to claim 1 or 2, wherein the polytetrafluoroethylene (PTFE) film is deposited by dipping the insulator body in a liquid bath of a PTFE containing liquid.
5. An electric insulator according to any preceding claim, wherein the thickness of the polytetrafluoroethylene film is from 10 to 80 ssm. ‘ 6. An electric insulator according to claim 5, wherein the said thickness is from 30 to 40 ssm.
7. An electric insulator according to any preceding claim, substantially as herein particularly described.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (7)
**WARNING** start of CLMS field may overlap end of DESC **.
the second, and final, coat of the polytetrafluoroethylene coating;
e) finally, further baking of the insulator and, in particular, of the double layer of
PTFE deposited on its entire surface, is carried out again at a temperature of about 4o00C.
At the conclusion of such operations the insulator body has been completely coated with a PTFE film having a thickness of some tens of ym; more precisely, the film preferably exhibits a thickness ranging from 10 to 80 pm, more preferably from 30 to 40 sm.
The PTFE coating of glass insulators has allowed, as mentioned hereinbefore, a substantial improvement in the behaviour and performance of such insulators to be achieved in operation under conditions of atmospheric pollution. Such improvement was clearly demonstrated in artificial pollution tests which the PTFE-coated insulators were subjected to.
It was possible to ascertain an improvement by more than two points, or grades, in the logarithmic scale of salinity, relative to the results obtained from the same uncoated insulator body, in the artificial pollution tests carried out according to the salt spray fog method (C.E.I. standards — Supplements S.
487).
WHAT WE CLAIM IS:
1. An electric insulator for insulating high voltage electric lines, which comprises an insulator body of tempered or annealed glass coated over its entire surface with a film of polytetrafluoroethylene (PTFE).
2. An electric insulator according to claim 1, prepared by sandblasting the surface of the insulator body, coating the entire surface with a thin film of PTFE, baking at substantially 400″C, applying a further coating of PTFE, and baking again at substantially 400 C.
3. An electric insulator according to claim 1 or 2, wherein the polytetrafluoroethylene (PTFE) film is deposited by spray painting the insulator body.
4. An electric insulator according to claim 1 or 2, wherein the polytetrafluoroethylene (PTFE) film is deposited by dipping the insulator body in a liquid bath of a PTFE containing liquid.
5. An electric insulator according to any preceding claim, wherein the thickness of the polytetrafluoroethylene film is from 10 to 80 ssm. ‘
6. An electric insulator according to claim 5, wherein the said thickness is from 30 to 40 ssm.
7. An electric insulator according to any preceding claim, substantially as herein particularly described.
GB2175878A
1977-05-24
1978-05-24
Polytetrafluoroethylene-coated glass electrical insulator
Expired
GB1603765A
(en)
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
IT2394177A
IT1082092B
(en)
1977-05-24
1977-05-24
ELECTRIC GLASS INSULATOR, COVERED IN PLASTIC MATERIAL
Publications (1)
Publication Number
Publication Date
GB1603765A
true
GB1603765A
(en)
1981-11-25
Family
ID=11211018
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB2175878A
Expired
GB1603765A
(en)
1977-05-24
1978-05-24
Polytetrafluoroethylene-coated glass electrical insulator
Country Status (5)
Country
Link
BR
(1)
BR7803255A
(en)
ES
(1)
ES470121A1
(en)
FR
(1)
FR2392477A1
(en)
GB
(1)
GB1603765A
(en)
IT
(1)
IT1082092B
(en)
Cited By (3)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
EP1748449A1
(en)
*
2005-07-25
2007-01-31
Siemens Aktiengesellschaft
Insulator with increased insulation capability
CN103500621A
(en)
*
2013-09-26
2014-01-08
国家电网公司
Porcelain insulating surface processing method for electric transmission line
CN114016808A
(en)
*
2021-10-26
2022-02-08
广东电网有限责任公司广州供电局
Cross arm
Families Citing this family (1)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
AT389185B
(en)
*
1986-12-18
1989-10-25
Isovolta
Electrically insulating component, and a method for producing it
Family Cites Families (4)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
FR1126829A
(en)
*
1954-07-05
1956-12-03
Licentia Gmbh
Outdoor high voltage insulator, ceramic material
GB915052A
(en)
*
1958-02-18
1963-01-09
British Insulated Callenders
Improvements in or relating to electrical insulators
GB1281583A
(en)
*
1969-07-02
1972-07-12
British Insulated Callenders
Improvements in or relating to electric insulators
US3922378A
(en)
*
1972-08-04
1975-11-25
Medical Evaluation Devices & I
Fluorinated hydrocarbon coating method
1977
1977-05-24
IT
IT2394177A
patent/IT1082092B/en
active
1977-12-13
FR
FR7737479A
patent/FR2392477A1/en
active
Granted
1978
1978-05-22
BR
BR7803255A
patent/BR7803255A/en
unknown
1978-05-23
ES
ES470121A
patent/ES470121A1/en
not_active
Expired
1978-05-24
GB
GB2175878A
patent/GB1603765A/en
not_active
Expired
Cited By (6)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
EP1748449A1
(en)
*
2005-07-25
2007-01-31
Siemens Aktiengesellschaft
Insulator with increased insulation capability
WO2007012627A1
(en)
*
2005-07-25
2007-02-01
Siemens Aktiengesellschaft
Insulator exhibiting increase insulating properties
US7800003B2
(en)
2005-07-25
2010-09-21
Siemens Aktiengesellschaft
Insulator with enhanced insulating capacity
KR101023861B1
(en)
*
2005-07-25
2011-03-22
지멘스 악티엔게젤샤프트
Insulator exhibiting increase insulating properties
CN103500621A
(en)
*
2013-09-26
2014-01-08
国家电网公司
Porcelain insulating surface processing method for electric transmission line
CN114016808A
(en)
*
2021-10-26
2022-02-08
广东电网有限责任公司广州供电局
Cross arm
Also Published As
Publication number
Publication date
FR2392477B1
(en)
1980-08-22
IT1082092B
(en)
1985-05-21
FR2392477A1
(en)
1978-12-22
ES470121A1
(en)
1979-02-01
BR7803255A
(en)
1979-01-16
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Legal Events
Date
Code
Title
Description
1982-02-17
PS
Patent sealed
1994-01-19
PCNP
Patent ceased through non-payment of renewal fee
Effective date:
19930524
