SU724620A1 - Method of preparing pulp for manufacturing electric insulation paper - Google Patents

Description

This invention relates to the preparation of paper masses for the manufacture of electrical insulating paper and is intended for use in the pulp and paper industry, in particular in the manufacture of electrical insulating paper. The electrical industry currently requires paper dielectrics with improved dielectric characteristics, the most important of which is electrical strength. An increase in the electrical strength of electrical insulation paper makes it possible to significantly increase the specific power and reliability of condsge: ators. The main factor determining the electrical strength of electrical insulation w -; One piece of paper, is the degree of fibrillation of the pulp. The mass should have uniformly developed fibers with flexibility, elasticity. The presence of undeveloped and coarse fibers, fines, and mucus, which are not Hell (yarn; yarn, 75), according to the structure of electrically-charged paper. A known method of preparing pulp for the manufacture of electrically insulating paper, through which the content of fibrillated fibers in a mass of 94–98% with a length of fibrils is milled. 0,25O, 35 mm and a weight index of the average fiber length 14-g20 dg fl}. There is also known a method for obtaining a mass with a high degree of fibrillation in roll 2. The disadvantages of the method are the economics of the roll, which is associated with a large expenditure of energy, the frequency of its operation and the duration of the nont preparation process. and a new indicator of the average fiber length of 14-2O dg requires an order of 50 hours. The closest to prr-ilpt-rmpmu, is the method, i.P. iiiiiituii argpr mr.shchch c.

372

milling to the extent of grinding the boom with a mass of 35-40lJJP, swelling of the mass in the basin and the main grinding of the degree of grinding 96-98 SHR.

However, this method does not provide a mass with a high degree of fibrillation.

The purpose of the invention is to reduce the consumption of electric power while increasing the electrical strength.

The goal is achieved by the fact that the pulp mass during swelling Yrrpuskayut 1O-ZO times through Tidropiia 204:

The nJDit unit is a 1Q-QO mini progop for example.

Table 1 shows the dependence of the strength of the consensator paper on the number of mass passes through the apparatus and their duration.

From tab. Figure 1 shows that the highest value of the electrical strength of capacitor paper is observed at 15-30 passes of the swellable mass through the instrument of hydrodynamic action with a duration of one pass of 30-40 minutes.

Table 1

46-48

50-52

40-45 5О-52 42-45

As a result of this treatment, the fiber becomes more flexible and elastic and prepared for fibrillating during the main grinding stage.

As can be seen from the table. 2, the degree of grinding in the process of swelling practically does not grow, which indicates a deep swelling of the fiber, which further promotes good fibrillability.

Example. Sulfate unbleached pulp is dissolved in gidrorazbavitV table. Figure 2 shows the characteristics of paper pulp in the process of swelling under dynamic impact on the fibers.

Tabliya2

They accumulate in the pool to a concentration of 3.0-3.5%, after which they are fed to the grinding machines of the preliminary grinding, where the degree of grinding of the mass of 3 5-4О1ПR is reached. Then the mass enters the pool of swelling with a capacity of 2530 m, to which is connected hydrptsina ichRsknn pyarlt (iptermeer meeppie, p13rpl5101G1P with bpsseynom closed loop). After the expiration of & h, the swollen mpsss is placed on the main paoNioia collector. The degree of fibrillation of the finished mass comprehends 94-98%,

Predla

1.2

10.0 raeNfbifl

Known U (laboratory) Oh, About

Known (r.rmyshlenny :) 10.0 From table. 3, it can be seen that the proposed method increases the electrical strength by decreasing the electric energy consumption in comparison with the industrial method, and the processing time is reduced compared to the laboratory method. Formula and 3 O R ee e- The method of preparing the mass for the manufacture of electrical insulation paper by pre-grinding, swelling and grinding cellulose, so that, with the reduction of electric power, while increase the electrical strength of the paper, the pulp mass when swelling

A further process for the manufacture of electrically insulating paper proceeds according to the known process conditions.

In tab. 3 shows the performance of capacitor paper from the mass prepared in different ways.

Table 3

16-28 1822

50-52

5 Oh, Oh

12505

5O

38-42

2419О2 is passed 10-30 times through the hydrodynamic apparatus with a duration of one pass 1Q-60 min. Sources of information taken into account in the examination 1. USSR author's certificate number 518548, cl. fi 21 N 5/00, 1975. 2. Nemanikhin VN and others. ProizvbdsrBO thin technical papers. Light industry, 1965, p. 21-22. 3. Pashinsky V. F, et al. On the question of the optimal scheme of grinding mass with a high degree of fibrillation. Trudy UkrNTTB, 1974, No. 16, p. 95-97 (prototype).

Claims (1)

Claim A method of preparing pulp for the manufacture of electrical insulating paper by preliminary grinding, swelling and ₃₅ grinding of cellulose, characterized in that, in order to reduce the energy consumption while increasing the paper’s electric strength, pulp is passed 10-30 times during swelling 40 through a hydrodynamic apparatus with a duration of one pass of 10-60 minutes