CS208564B1 - Method of making the cases for electrotechnical purposes and device for executing the same - Google Patents

Description

(54J Method of manufacturing cabinets for electrical purposes and apparatus for its implementation)

The invention relates to a process for the manufacture of housings for electrical purposes and to an apparatus for carrying out the process.

Cabinets for electrical purposes are thin-walled box constructions made of cement-sand mortar reinforced with steel armature.

Cabinet fittings usually consist of reinforcing steel rods of 6 and 3 mm in diameter and Rabbit mesh. The parts of the fitting are connected to the mesh on a single-purpose device to the prescribed “basket” shape. The fitting is then inserted into the assembled mold coated with the separator. For smaller cabinets, the mold is placed on a vibrating table, filled with mortar and vibrated. For cabinets of particularly complicated shapes, the basket is manually plastered.

The disadvantage of this procedure is the high workmanship of the fitting, which is manufactured manually for each cabinet due to the complexity of shapes and variety of product range. Also, manual plastering of baskets results in low productivity of the entire production process.

According to the invention, the above-mentioned drawbacks are overcome by a method of manufacturing cabinets for electrical purposes. It consists in mixing the chopped non-metallic fibers, for example basalt, polypropylene or glass in a volume fraction of 2 to 6%, with cement-sand mortar with a water coefficient of 0.4 to 1.4, which is then reduced by centrifugation to 0 35 to 0.5, and then the molded material, which is subjected to vibration, is filled with the resulting mortar-fiber sheet in a planar configuration.

The principle of the apparatus for carrying out the method provided with a sieve basket and a drivetrain consists in that the sieve basket with a removable sealing jacket and a removable lid is attached to the rotating plate of the drivetrain, tilting for mixing position to the nozzle container and horizontal wherein the sieve basket is stored in a larger container when the sealing jacket is removed.

The method according to the invention allows the production of cabinets, i.e. spatial components, of relatively complex shapes; it also makes it possible to dramatically increase production productivity by eliminating the handicraft of the fitting or to use chopped fibers as waste from other industries.

The method and apparatus of the invention are described in more detail below by way of example.

Example

For the manufacture of cabinets for electrical purposes, polypropylene fibers 0 80 μ with a length of 2 to 9 cm at 3 ° / o reinforcement were used, which were mixed with cement-sand mortar at a ratio of cement: sand = 1: 2 and higher water coefficient. This mixture was filled with a 400 X X 600X235 mm metal mold and the whole was vibrated on a vibrating table. The cabinet was demolded after 24 hours. The product was crack-free and tested with positive results.

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208 584

A device for replacing the reinforcement of cabinets for electrical purposes is shown in the accompanying drawing, in which the line for the manufacture of cabinets is schematically illustrated.

Giant. 1 shows a schematic front view of a strainer basket during filling and in the function of a mixer,

Giant. 2 is a front view of the strainer basket in the centrifuge function,

Giant. 3 shows a plan view of the basket according to FIG. 2,

Giant. 4 shows schematically the mold during filling and vibration.

The fiber dispenser 1 is provided with an adjustable air pressure nozzle 2, a grate 3 and a nozzle 4 opening into a rotatable sieve basket 5. The sieve basket 5 consists of a bottom 6 formed by a shallow perforated sheet metal plate, a peripheral perforated wall 7 reinforced by partitions 8 with rounded edge. The perforated wall 7 may be coated inside with filter material 9, with an outer removable sealing jacket 10. The screen basket 5 is covered with a removable lid 11 in the form of a non-perforated annulus and attached to a rotating plate 12 of the drive train 14 which is located in a larger collection container 13 of the excess cement milk flowing through the aperture 15. The axis of the sieve basket 5 may assume two positions, namely a tilted position for filling and mixing or a vertical position for spinning. The drivetrain 14 with the sieve basket 5 is equipped with a dual speed range, slow for mixing and fast for spinning, as well as a speed regulator, tachometer, switch and monitoring device. The mold of the housing 18 is located on the vibrating table 17; the enclosed vibrator 18 can be used for larger cabinets.

The procedure for working on the device is as follows:

The sieve basket 5 in an inclined position and provided with a removable lid 11, filter material 9 and a sealing jacket 10 replaces the concrete mixer. After starting a slow speed, the sieve basket 5 is filled with a mixture of sand and cement with the addition of water, approximately to twice the amount of the desired water coefficient. After a homogeneous slurry has been formed, the filaments blown through the grate 3 start to flow through the nozzle 4 in order to retain the tufts. At the end of this operation, the slow rotation of the sieve basket 5 is stopped, brought to the spinning position and attached to the centrifuge plate 12, the sealing jacket 10 is removed and the rapid speed range is started. As a result of centrifugation, excess cement milk is pushed through the filter material 9 and the perforated wall 7 of the sieve basket 5 and sprayed onto the walls of the larger cement milk collection container 13; the excess cement milk flows through the aperture 15 and can be reused in the manufacturing process. After the water coefficient has been lowered to the prescribed limit, a pre-formed fiber-reinforced mortar strip remains in the planar configuration between the partitions 8 on the perforated wall 7 of the sieve basket 5, and a fiber-reinforced fiber-reinforced mortar layer in the planar arrangement. The filled mold is vibrated, thereby bonding the individual "pre-fabricated" strips into one product. The molded article is then allowed to cure for the necessary time before shipping. This technology eliminates the need to handle the slurrying of the slurry of mortar and fibers, which could cause undesirable agglomeration of the fibers.

The described device is not the only possible example of a method of replacing the existing reinforcement of the electrical enclosures of the invention. The drive assembly 14 can be divided into two separate machines, a mixer and a centrifuge with a replaceable sieve basket 5, which can be transferred and attached separately to each machine. In addition to electrical enclosures, other thin-walled cementitious products can be reinforced in this way.

Claims (2)

SUBJECT Process for the manufacture of housings for electrical purposes, characterized in that the chopped non-metallic fibers, for example basalt, polypropylene or glass, in a proportion of 2 to 6% by volume, are mixed with cement-sand mortar with a water coefficient of 0.4 to 1.4. It is reduced by centrifugation to a value of 0.35 to 0.5, and then the molded material, which is subjected to vibration, is filled with the resulting preform consisting of a strip layer of mortar and fibers in a planar configuration. OF THE INVENTION 2. Apparatus for carrying out the method according to claim 1 provided with a sieve basket and a drivetrain, characterized in that the sieve basket (5), provided with a removable sealing jacket (10) and a removable lid (11i), is hinged for the mixing position to the container (11 with the nozzle (4) and at the horizontal spinning position), the sieve basket (5) being stored in the larger container (13) with the sealing jacket (10) closed.