SU9310A1 - A method of tanning leather and tanning vats - Google Patents

Description

The existing methods of tanning leather have some drawbacks, such as: slowness in the process of work and high energy consumption. The proposed method aims to eliminate these disadvantages. In FIG. 1 shows a general view of an apparatus for carrying out a method for tanning leather; FIG. 2 and 3 are the same in vertical sections, and FIG. 4-skin tightening frame. Leather tanning is carried out in three steps: hatching, tanning and fixing. For continuous operation, it is necessary to have at least four identical swimming pools equipped with electrical equipment. At four pools, the order of tanning will be as follows: if in the first pool there is a catch of one batch of leather, then in the second, at the same time, the second batch is tanned, and in the third one there is a fixation, if needed, and washing-out the third batch. The fourth vat is free and is filled with freshly prepared tailing. Since the processing time in all three stages is almost the same, then, at the end in all three basins of the processes occurring in them, skin washing and further processing; solutions of the individual, tanning and fixation pools of the pumping pool - in the second, the former tanning. To perform this change of juice, the piping system and the pumps of all vats must be properly connected. Bombolye, devoid of alkali residues (no coagulation occurs in the presence of OH-ion) or acid, if it is consumed from it (in the presence of H-coagulum ion goes quickly and the face can harden), immerses it into a solution of tanning juice or extracts with a strength of up to 1% of the tannid content, taken from the pool, where there was a sign supported by a solution from a tanning basin, if necessary. a constant electric current with a voltage of 90-volts and above, depending on the distance between the electrodes and the electrical conductivity of the solution, by a force of 5-6 amperes. Once the fixings are removed, the proms are pumped out of the fourth tank that has just been filled with leather; From the second tannery to the main tannery and from the third fixation. Prepared in the usual way, the pool is filled

The current control changes every minute. As part of the tannins is absorbed from the solution, it is reinforced by sap from the tanning basin, which is added to a fresh strong solution or juice.

The duration of the hatch depends on the type of skin, strength and acidity of the solutions and the strength of the current.

At the end of the roll and tanning of the previous batch of leathers, the solution from the roll is distilled into an empty pool, and the pool of the catch is filled with a solution from the previous tanning, while increasing the voltage to 60-110 volts and higher, and the current to 11-14 amps, changing its direction also in a minute.

The strength of the solution in the tanning basin is kept from 27-2-3%, depending on the thickness of the leather and their density, by regulating the current and temperature of the juices - the rate of tanning and the amount of tanning material deposited in the pores of the skin. Work on weak juices is carried out in accordance with the coagulation law of two colloids, according to which coagulation can be carried out with weak solutions of calloid-coagulant in order to avoid stopping coagulation with medium solutions due to enveloping the tannic particles, skin colloid particles and skin satiation with tannic extract in the process of tanning in strong solutions. You can learn about the readiness of the leathers on trial pieces of leather, pre-hanged among the frames or on the cuts in the leathers, raising the frame from the pool.

To speed up the process of coagulation of tannins with protein substances of the skin, if it is deemed necessary, do this: after finishing tanning and freeing the pool from tannic solution, the pool with the doji is filled with a coagulant solution and passing an electric constant current of 30 to 35 volts - 5-6 amps help the penetration of coagulant into the skin thickness. Coagulant solutions should be weak, not higher than 0.3%, in order to avoid wasting them when removing the skin from the solution and coagulating and dissolving the skin substance. . In addition to the known coagulants, -aluminum salts and magnesium sulphate, tanning may use alumina alum and sulphate, alumina for soft skins or a mixture of magnesium sulphate and alumina salts for heavy skins. Organic matter can also serve as a coagulant, for example, neufuchin.

The end of fixation can be recognized by the absence of leaching of tannins in pure water from samples and their cuts. Depending on the skin thickness oTi, the density and strength of the current during fixation may vary. After fixation, the skin is washed in clear water from excess coagulant and further processed by rolling, drying, finishing, etc.

The whole process of tanning and fixing for the plantar (65 pounds and above) will take: 3-4 days tanning, 3-4 days tanning, and fixing and washing - 3 days - only about 10 days. The number of working hands is reduced due to the destruction of the leather bulkhead operation in the retrieval and transfer from one vat to another. The skin, stretched over the frame and placed in the pool, stands in one place during the whole period of tanning. When working on weak juices, toBap comes close in quality to sypny.

 A basin of leather, stretched on a frame, placed vertically in it in an amount of up to 150 pieces, is arranged with the upper edge behind the floor with the floor of the room, walls and bottom 2 of concrete or brick on cement and equipped with asphalt lining. The bottom of the pool is double ; of these, the upper 7 is wooden, trellised, with openings of approximately 6–8 m / m, divides the basin into two parts: the upper for moving the framework with leathers and the lower

To evenly drain the pumped solution through three pipes 9 with openings for suction of the solution along the entire length of their part, lying on the bottom floor of the basin. The pipes are connected near the suction inlet of the centrifugal pump 10, operating from the electric motor 17 or from the transmission and pumping the solution from the suction pipes 9 through the discharge pipe 11 and spare tank No. 12. From the reserve tank 12 through pipes 13 and the adjusting valve 14, the solution if need backed up in stock-. tank, goes by gravity through the holes in the pipes 13 in the upper part of the pool, thus completing the circulation of the solution. The calculation of the pump ,, and pipes must meet the complete change of the solution in the pool, approx; . within an hour. In parallel with the end walls of the pool, electrodes 3 made of lead-sheet copper, tinned copper, or pressed carbon, depending on the acidity of the juices, are placed from the side walls and bottom with insulators.

wires 5 with clamps switch 19, every minute the direction of the direct current changing from the source of current. In order to separate the solution from contact with the body hydrogen at the moment it separates on the electrode and coagulates tannins, the electrodes are separated from the pool by porous partitions from a cloth, cloth or leather tightly on the frame entering the grooves of the side walls, and the bottom of the pool for better isolating the electrode from washing with a tanning solution. The electrode chamber 30, separated by a porous partition, has each of its tube 16 with a tap, draining a solution with sediment from the bottom of the chamber, and a tube 15 with a tap, supplying fresh water to the upper part of the chamber to replenish the waste and maintain the solution that washes the electrodes,

more liquid than the rest of the pool solution. Frames 26, 27 and 28

with the skin taut in them, they descend parallel to the electrodes and porous partitions and rest on the protruding ends of the upper plank on the edge of the pool.

The design of the frame and the skin tension in it is shown in FIG. 4, where the frame consists of 4 planks of durable wood with protruding strips 1. Rollers 5 made of hard wood, ebonite or fiber, in an amount necessary for complete leather shaping, are attached to the frames. Through all the rollers passes one round strong cord, the ends of which are fixed after pulling the leather to the slingshots or hooks 9 on the upper side of the upper plank. Moving rollers with hooks are attached to the same cord in the gaps of the fixed rollers to grip the edges of the skin with a simple crochet. After securing the movable rollers on the skin table with the hooks, the skin is simply stretched to all directions evenly by the tension of the cord 7 and the ends of the cord are fastened to slingshots or cracks on the upper side of the upper plank. Tensioning of the cord can be conducted either directly to the opposite slingshot 9 or through the side fixed block 8.

The subject of the patent.

1. A method of tanning leathers stretched in frames using an electric current-changing tank with electrode chambers that changes every minute, characterized in that the hedge hung in the framework of the hem is exposed to juice of 1% at a current of 5B amperes and 90 volts voltage, and then oak and juice at 3% with an electric current of 11-14 amps. and 60-110 volts, followed by treatment with mineral or organic coagulants, to accelerate the fixation of leather on the fiber at a current of 5-6 amperes and 30-35 volts or without such additional processing.

2. Acceptance of the method indicated in paragraph 1, characterized by the use of coagulants, aluminum alum, and alumina sulphate for soft leather and magnesium sulphate or its mixture with aluminum salts for heavy leather as skin-fixing leather.

3. Double tanks for carrying out the method specified in clauses 1 and 2, equipped with a false bottom, electrode chambers and a system of pipes for transferring juices and associated with a pump for pumping juices and an overlying tank for them, characterized in that in each of the tanks between brick walls-, kami 2 with asphalt lining 1,

longitudinal of which are provided with grooves b, partitions 4 with tensioned cloth or leather are inserted, separating chambers 30 with electrodes 3, connected by wires 5 to a switch 19 of direct current, equipped with pipes 15 and 16 for changing water in chambers 30 (Fig. 1 -3)

4. With the tanks indicated in p. 3, the use of frames for stretching the leather to be treated, provided with protruding strips 1 for hanging the frames with rollers 8 and 5 for pulling the cord 7 with movable rollers b, the hooks of which 10 are hooked over the edge of the skin (Fig . four).

fig1.

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