DE2037926C3 - Porcelain electrical insulator and process for its manufacture - Google Patents

Description

that of feldspar porcelain is. The crystalline phase

₄ o of the fired Kristobalitporzellans contains not only

Mullite and quartz, but also cristobalite crystals,

The invention relates to an electrical high-strength which is strong for a thermal treatment Porcelain insulator, especially solid core insulator, tend to have waxes. The presence of these knstobaliteinem The content of mullite, crystals, quartz and corundum crystals makes the mechanical strength unimportant a high flexural strength after external damage guug feldspar china. The mechanical strength of

In the case of electrical porcelain insulators, undamaged Kristobalit porcelain is lower three different porcelains are currently used, namely that of porcelain containing aluminum oxide, but Hch 1. feldspar china, 2. alumina the rate of decrease in mechanical Porcelain and 3. Kristobalit porcelain. 5 ° strength of undamaged plastic porcelain

1. The feldspar porcelain is obtained in that due to the size effect is smaller than that a mixture is fired which consists essentially of the alumina-containing porcelain. Also is up to 30 percent by weight quartz material, 20 to 40 percent the flexural strength of externally damaged Kristo percent by weight Feldspar material and 40 to 60 gebalite porcelain are not high enough to be weight percent clay material. The crystalline 55 withstand particularly high bending stresses This fired porcelain phase consists of 10 to 10 percent by weight, which in the case of electrical porcelain insulators Quartz and 10 to 20 weight steps.

Percent mullite, and the rest consists of nonhomo- In DT-AS 12 81 917 is a porcelain object

suitable glass. The raw material for this Feldspalpor- described, which consists essentially of 100 per cent by weight is relatively cheap and has a large number of standard porcelain and 3 to 15 additional porcelain Processability so that it is suitable for electrical parts by weight of mullite, 3 to 36.5 parts by weight of plastic porcelain insulators has been used. It has builds and 3 to 10 parts by weight of aluminum oxide, however the disadvantage that its mechanical strength stands.

is not very high, so that it will not be used for electrical purposes

Porcelain insulators can be used, which have a 65 mechanical strength through the addition of the mullite have to withstand high mechanical stress. Improved that when burning because of the mulht addition

2. The porcelain containing aluminum oxide was deformed by the addition of aluminum, the mechanical strength of the feldspar miniature oxide is prevented, and because of the additive

^{3 4}

MuIHt and aluminum oxide occurring decrease of 1: 9 to 1: 1 and where the above-mentioned

thermal expansion through the addition of quartz material, such a grain size distribution

♦ nhalit compensated. So the mechanical shows that not more than 20 percent by weight of the ι egg-

■ the above-mentioned porcelain object chen an effective diameter of more than Jυ μπι

Value higher than the top 5. The mass A is determined with the help of a ruiveri-

'"ffitaErtalng in" an electric .. or made of powdered, calcined bauxite wöbe Ä Rh

Ertalng in ", an electric .. or made of powdered, calcined bauxite PnÄnfsolMor with an improved mechanical this bauxite is produced by raw Change in the process of manufacture ^ - "- ^ 'e

E £ a ± w «fts ätSs

E-compound A and 10 to 35 weight percent of the product thereon ™ einerte a ^ '^' ^^ f

ozent clay substance and % * ™ ^ $ ™ ** ™ ^ 'öTb "90 percent by weight of the mass A and 10 to

ΐκ, Ο and inevitable impurities shut- 30 shear **. ™ «™ Jj ^ J ^ 'S dehydrated and too

is stmmengesetzt, wherein the ratio of K ₄ O way to hergesteUt Mtschung _{is then ge.}

NaT lies between 1: 9 and 1: 1, and the quartz mea- emea body deforms ^ u _k "P _wjrd ^. ^

material has a grain size distribution that not Uocknet una αeg burned to a

More than 20 percent by weight of the particles with a temperature of 120C ^ b, s13 0 g ^ ^. ^. ^ _p

Active diameter of more than 10 μ »vorheejn. 35 J ^^^ SS, consists of muilit and quartz and

and in which the mass B consists of an aluminum oxide ^ Konina ^ _weight percent Kristobalit

^The invention is held in the following description that when burned porcelain

explained in greater detail, in which also £ * g * g * g% _{G 'ewichtspr} Dozent Kristobaht s to the drawings -

T ^ _g ^U r ⁿ a ^d phical illustrations showing a comparison test cases ₄₅ --'- ^^^^^^ nf ei ^ he deich the bending strength of inventive etek- burned WUR ^ g _{1 Alminium} oxidmatenal, see porcelain insulators with those from her- M s eu ^ dO

S £ SeS £ iSi £

Quartz, Kaohnit and Senzit unQ _{against the} strength of

The amount of Krislobalite was quantitatively effective diameter of more than 10 μm,

tive X-ray diffraction analysis determined. is the following. The one present after firing

From Fig. 1 it can be seen that the flexural strength of Kristobalit depends on the amount of SiO ₂ , the amount of K ₂ O + Na ₂ O from externally damaged porcelain test bodies and the ratio of 50% of the flexural strength of undamaged 5 K ₂ O to Na ₂ O ab, which is pre-porcelain debris in the formed glass phase when the amount is when the porcelain body is more than 25% at the highest crystallite, but that it is fired at temperature. More than 83 percent by weight of less than 40% of the undamaged porcelain test grains SiO ₂ and less than 2 percent by weight of K ₂ O per is reduced if the amount of crystals does not - | - Na ₂ O lead to an increase in the vitrification stress of more than 25 percent by weight. It is also open temperature, which in practice makes it impossible to visibly cause the resistance of electrical complete sintering to increase when an electrical porcelain insulator which is externally damaged is a porcelain insulator with a large diameter the porcelain body more than and with a solid core to manufacture. Contains 25 percent by weight of Kristobalit. F i g. Fig. 1 shows the reason why the amount of the Al ₂ O ₃ also increases in the amount of the alumina material that the flexural strength is limited to 15 to 28% by weight with the increase in the 15 mass A, and that it is as follows. When the SiO _{2 is} 65 to 83% by weight of flexural strength of an externally damaged insulator, the K ₂ O H-Na ₂ O is 2.0 to 4.5% by weight of its alumina material content is 0% by weight and the ratio of K ₂ O to Na ₂ O cent, is in the same order of magnitude as 1: 9 to 1: 1, then the amount of Al ₂ O ₃ falls that of porcelain bodies, the 10 percent by weight, of course, in a range of 15 to 28 percent by weight and 25 percent by weight Alumina material cent.

included when the amount of the Kristobalite is less than The reason why the grain size distribution of the

25 percent by weight is, with the result that the quartz material is no more than 20 percent by weight

Flexural strength of externally damaged insulators Particles with an effective diameter greater than

has a low absolute value. 25 is limited to 10 μm, is the following. This loading

It can therefore be seen that the amount of aluminum restriction ensures an increase in the SiO ₂ component of oxide material by more than 10 percent by weight, which should be in the glass during the firing, and that the amount of crystals dissolves after phase, so that more than 25 percent by weight of the firing should not be less than 25 percent by weight of Kristobalite crystallize. 30 The reason why the alumina material is the

As already mentioned, it is desirable that the por mass B is limited to 10 to 35 percent by weight,

cell body contains a large amount of Kristobalite. is the following. The more alumina material in the

The maximum amount of Kristobalite is present in the porcelain mix that makes up the porcelain body

bodies that are fired from mixtures at 1200 to 135O ° C, the higher the mechanical

are burning, which consist of the masses A and B, 35 strength of the insulator. On the other hand, do more

however, should not exceed 40 percent by weight. as 35 weight percent aluminum oxide material

If the process body is more than 40 percent by weight, higher firing temperature for sintering the porcelain

cent of Kristobalit contains, then the feldspar decreases body necessary, while less than 10 weight per-

and the quartz too, which has the consequence that the glazed aluminum oxide material has a decrease in the

sungstcmperatur rises considerably. 4 ° result in the mechanical strength of the isolator,

The reason why the mass A is essentially not so that the objects of the present invention

feldspar material, quartz material and clay material are sufficient.

is the following. First, the quartz material is The reason why the firing temperature is dissolved to 1200 rial in the feldspar glass, which limits Kristobalite to 1350 ° C, is as follows. When that becomes crystallized. Furthermore, the sparate material - porcelain body is required at a temperature below 1200 ° C in order to produce sparate glass. Finally, the glazing of the porcelain will give the clay material, which has incomplete plastic properties, while, if the porcelain has good workability of the porcelain body at temperatures of more than 13> 0 "C, the body will be burned, the porcelain bodies have an unfavorable

The reason why the mineral composition of 50 exhibits a tendency to decrease in mechanical strength. Mass A to 10 to 20 percent by weight feldspar, 30 crushed aluminum oxide or calcined structure

Up to 60 percent by weight quartz and 20 to 50 percent by weight xite, as are available on the market, can

prozcnl tone is limited is the following. The above can be used as the aluminum oxide material

The use of calcined bauxite yields a limitation Process for the production of electrical porcelain 55 lower pre-glazing temperature of the porcelain body

insulators practical to realize to get electrical pers than the use of on the market ·

Porcelain insulators with stable properties and light calcined aluminum oxide, and besides

with consistent quality. The result is the advantage that an electrical!

nis is. that the fired porcelain body 25 to 40 Ge porcelain body with a solid core, the one large

contains an important percentage of crisis globalite. 60 in diameter, comparatively slightly tall

The reason why the mass A can be represented chemically.

from 65 to 83 weight percent SiO ₁ , 1S to 28 weight percent. The invention will now be based on the following case

percent Al ₁ O ₈ , 2.0 to 4.5 percent by weight K ₁ O play explained in more detail. In each of the following!

(- Na ₁ O and unavoidable impurities. Examples of materials were used before

stands why the ratio of KtOzUNa ₁ O is between 65 mixed composition and its mineralogical 1: 9 and 1: 1 and why the quartz material has a composition which by X-rays

has such a particle size distribution that diffraction was not measured, in the following table

greater than 20 percent by weight of the particles are indicated.

Table 1

Loss on ignition On the Calcined
Bauxite
Dcmerara • Fukushirna-
Quartzite • Kumamoto
Pottery stone " • Nagasaki-
Feldspar » »Niigata-
Feldspar " • Gifu-
Gaerome
Volume" SiO ₂ market
available
aluminum Al ₂ O ₃ oxide 0.30 0.20 2.96 0.67 0.39 12.64 Chemical Fc ₂ O ₃ 0.18 4.20 99.58 78.42 80.02 66.83 50.34 Together TiO ₂ track 91.23 0.02 14.35 12.56 17.72 33.87 men CaO 99.74 1.07 0.04 0.75 0.08 0.10 1.32 settlement MgO 0.02 2.90 track 0.15 0.04 track 0.63 Weight K ₇ O track 0.14 - 0.10 0.57 0.18 0.06 percent Na ₂ O 0.05 0.05 - 0.07 0.02 track 0.34 Total track 0.04 - 3.08 0.43 10.99 0.78 quartz 0.02 0.04 - 0.21 5.66 3.60 0.13 Kaolinite 0.24 99.97 99.84 100.09 100.05 99.81 100.11 Scrizit 100.25 100.0 60.8 38.1 9.8 8.3 Minera Feldspar - - 7.6 - - 87.1 logical - - - 30.5 - - - Together - - - 0.5 46.0 89.7 - menset - tongue Ge weight percent

Example 1

A porcelain with the composition given in Table 2 below was used.

Table 2

Test pieces were measured by the same method as described above.

composition
(Weight percent) HrCitKlungs-
gcmllßc! ·
Porcelain Conventional
aluminum
oxide hooks
porcelain 20th
20th
25th
35 20th
25th
17th
38 Alumina ....
I'ukushima quartzite
Nagasaki feldspar
Niignta feldspar ...
Gifu-Oacromc clay 100 100 Inagesamt

The Fukushima Qunrzit was previously written in this way grind so that 15 percent by weight of the particles had an effective diameter greater than 10 microns.

The final mixture produced was ground so that 18 percent by weight of the particles were one have an effective diameter of more than 10 μ.

The Gcmlitch having the composition shown in Table 2 became a rod-shaped !! processed massive test body, which had a diameter of 120 mm. The test body was ^{fired at 1300 °} C., a porcelain being obtained which had the properties given in Table 3 below. The amount of Krlstoballl present in the fired test body was determined quantitatively by means of X-ray diffraction. The average security values of undamaged and damaged

Table 3

Inventive
if necessary
porcelain Conventional
porcelain Amount of crystal balits weight percent 29.4 0 Flexural strength of undamaged Porcelain oil 1340 kg / cm » 1150 kg / cm ' Flexural strength of externally damaging digtem porcelain (2 mm deep) Λ 2 ... 700 kg / cm * 340 kg / cm ' (52 / (H 100 (%) .... 52.2 29.6

Boispicl 2

25 percent by weight of calcined bauxite, which was used as an aluminum oxide material and was pulverized in such a way that 30% of the particles had an effective diameter of more than 10 μ, 22 percent by weight of Kumamoto pottery stone, which was ground so that 18 percent by weight of the parts had an effective diameter of more than 10 μ a, 23 percent by weight Nagasaki feldspar and 30 percent by weight Glfu-Oaorome clay were mixed together. The 1 bag obtained on this catfish was further ground in such a way that 20 percent by weight of the particles had an effoct diameter of more than 10 μ. For example, an overhead line insulator with a massive core 1 was provided, the dimensions of which were after the fire

700821

The following were: cylinder diameter 125 mm, umbrella diameter 220 mm and total length 1150 mm. This test insulator was fired at 1280 ⁰ C. The amount of the Kristobalite present in the fired test insulator was 34.8% by weight (determined by quantitative X-ray diffraction analysis). The average flexural strength δ 1 of the undamaged overhead line insulator was 1280 kg / cm ² . The average flexural strength 62 of the test insulator when the three panels were knocked off with a hammer in the vicinity of the portion subjected to the maximum tensile stress was 660 kg / cm ² . The value <52 / <51 · 100 was therefore 51.5%. In contrast, a conventional electrical Kristobalitporcelain insulator, which does not have aluminum

10

contained the following values: (51 = 860 kg / cm *, (52 = 410 kg / cm ² and <52 / ol x 100 ⁰ / o 47.6 Vo.

A conventional porcelain alumina electric insulator whose alumina material content 25 percent by weight showed the following values:

oil = 1200 kg / cm ^s , <52 = 420 kg / cm ^a and 02 / 01-100

= 35%. The above-mentioned results are shown in FIG. 2 shown.

The electrical porcelain insulators according to the invention, which have excellent mechanical strength and excellent flexural strength after a have external damage, represent a considerable improvement on the previous high-strength electrical porcelain insulators for high-voltage and ultra-high-voltage lines.

For this purpose 2 sheets of drawings

Claims (3)

improve porcellans. The aluminum oxide-containing patent claims: Porcelain is obtained by a mixture of 1. Electrical high-strength porcelain insulator, ins- ular burns in which ^d "P * ^^^ ™ ** special solid-core insulator, with a high flexural strength or complete strength as well as a Te 1 of the field chip material strength after external damage, the MuIUt, S and a part of the clay material, containing 20 to 40 Ge-Kris? obalit, quartz and corundum, thereby replacing weight percent alumina ^ isL D ^ kmtalg eke η η ζ cal η et that it consists of a shaped line phase of this fired porcelain contains 20 to a mixture of 65 to 90 percent by weight of a 40 percent by weight alumina depending> mehi: contains aluminum c, -mass a and 10 to 35 weight percent of an oxide the porcelain, the large mass is se.ne B is fired so that the porcelain body io mechanical strength nwiw; aw _t ·.
25 to 40 percent by weight Kristobalit contains, in which tests have shown that the strength of a mass A consisting essentially of feldspar, quartz and glazed test specimen, consisting of alumino-oxide-containing clay material, has been produced in mineralogi porcelain, m of the order of SSdIu. 10 to 20 percent by weight field from 1200 to 1700 kg / cm · lies. The aluminum oxide spar, 30 to 60 percent by weight quartz and porcelain containing 20 to 15 have recently been used frequently for 50 percent by weight of clay as well as in chemical-electrical porcelain insulators, which in terms of 65 to 83 percent by weight SiO _{2 have} excellent mechanical strength Aluminum-15 to 28 percent by weight Al ₂ O ₃ , 2.0 to 4.5 mineral oxide-containing porcelain, however, has the residual weight percent Na ₂ O + K ₂ O and the inevitable part that one is composed of impurities in the design of an electrical porcelain , whereby the »o lanisolators despite the excellent mechanical strength ratio of K ₂ O: Na ₂ O between 1: 9 and 1: 1 ability of the test sample is a large safety factor m, and the quartz material has to calculate a grain size, namely from has the following basic division that no more than 20 weight percentages: (a) When the diameter of the porcelain body percent of the particles increases with an effective diameter, i Ann the distribution of cracks and knives of more than 10 μΐη are present, and in which the 25 defects are greater, with the result that the homogenous mass B of an aluminum oxide material is lost before the material; In other words, _stent means that the mechanical strength decreases 2. Electrical porcelain insulator according to claim 1, from the size effect. (b) The mechanical strength characterized in that the alumina decreases when on the surface of the electrical material consists of calcined alumina. 30 porcelain insulator due to rough handling 3. Method of making a porcelain iso- during transport and during manufacture Lators according to one of the preceding claims, there are scratches or if on the surface of the characterized in that the mixture of the electrical porcelain insulator is damaged by Mass A and mass B with the addition of water malevolence, such as. B. with a rifle shot, etc. produced in a drum, the mixture dewatered 35 caused. and formed into a body, the body dry- The Kristobalit porcelain is obtained by net, and the dried body that burns a mixture at a temperature-whose chemical burns Zuratur 1200-1350 ⁰ C. composition essentially the same as that