US1129984A - Apparatus for preparing paper-pulp. - Google Patents

Description

E. D. JEFFERSON.

APPARATUS FOR PREPARING PAPER PULP.

APPLICATION FILED FBB.'7,1912.

I Patented Mar.2,1915. P

3 SHEETS-SHEET l.

E. D. JEFFERSON. APPARATUS FOR PREPARING PAPER PULP.

APPLICATION FILED FEB. 7,1912.

Patented Mar. 2, 1915.

3 SHEETSSHEBT 2. W Q Q;

llll E. D. JEFFERSON. 1 APPARATUS FOR PREPARING PAPER PULP. APPLICATION FILED FEB. 7,1912.

L1%9,9@40 Patented Mar. 2, 1915.

3 SHEETS-SHEET 3.

the bleaching industry as chemic.

j h ihi APPARATUS FOR PREPARING PAPER-PULP.

Application filed February 7, 1912.

To all whom it may concern Be it known that I, EUGENE D. .InrrnnsoN, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new anduseful Improvements in Apparatus for Preparing Paper-Pulp; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relatesto apparatus forpreparing paper pulp for use in paper manufacture. The paper pulp used in the manufacture of paper is made from various substances such as wood, rags, jute, grass, etc.

When rags are made into pulp it is necessary to draw or beat the rags, so that they are disintegrated into fiber and no.

longer retain the woven structure of the cloth. In the preparation of paper pulp, and particularly pulp made from rags, one of the necessary steps consists in boiling the material with alkali to soften the material, to remove/grease from the material, and to discharge any coloring matter. To bleach pulp for paper making it is treated with a solution of chlorid of lime which is known in Hitherto it has been the practice in bleaching paper pulp to beat the pulp in an open hollander with the bleaching liquor. A considerable part of the chlorin is lost by evaporation from the open hollander, and the process of bleaching is slow. These two things make the process expensive.

The object of the present invention is to produce an improved apparatus for preparing pulp for aper making.

with the alibve object in view, one feature of the present invention relates to an apparatus for drawing rags preparatory to their use in paper making.

Another feature of the present invention relates to an apparatus comprising two tanks in which the pulp is treated with a hot alkaline solution in the presence of steam, which acts not only to boil the alkaline solution, but also to blow the pulp back and forth between the two tanks so that the pulp is thoroughlymixed with the alkali and exposed to the action of live steam.

Another feature of the present invention relates to improved apparatus for bleaching paper pulp in closed tanks in which the Specification of Letters Patent.

Patented Mar. 2, rant.

Serial No. 675,965.

apparent to those skilled in the art from the following description.

In the accompanying drawings which illustrate the preferred embodiment of the present invention; Figure 1 is an end elevation of the apparatus; Fig. 2 is a vertical section taken on the line 22 of Fig. 1; Fig. 3 is a sectional view of the pilot valve; and Fig. 4 is a sectional view of one of the diaphragm valves. g

In general, the apparatus consists of two closed gas tight tanks which are adapted to receive a charge consisting of a mixture of paper pulp or rags and treating liquor and which are placed side by side and connected by two pipes which extend respectively from the top of either tank to the bottom of the other tank, and through which the mixture of pulp and treating liquor is adapted to be blown from the bottom of one tank into the top of the other tank. The pulp is blown back and forth by means of compressed air which is admitted to the tanks alternately by means of mechanism operated by the rise and fall of the liquor levels in the tanks. Stirrers are employed to still further stir and mix the pulp and treating liquor and to draw the rags into pulp when rags are to be treated. Each tank is also provided'with a rotatable drum-like strainer for draining off water during theoperation of washing the treating liquors from the pulp.

The apparatus will now be described in detail. The two tanks 4 and 6 are horizontally disposed cylindrical vessels with crowned ends. Two pipes 8 and 10 extend from the bottom of the tank 4' to the top of the tank 6 and from the bottom of the tank 6 to the top of the tank 4 respectively. The pipes 841ml 10 are "adapted to conduct the mixture of pulp and liquor from the bottom of one tank to the top of the other tank, and

are provided with check valves 12 and 14 respectively to prevent the back flow of air or steam from the top of one tank to the bottom of the other tank. Gate valves 16 and 18 are provided in the pipes 8 and 10. When the material to be treated is rags, the rags in a chopped condition are put into the tanks through manholes 19. When the charge to be treated consists of pulp' mixed either with water or with alkali or with bleaching liquor, the mixture of paper pulp and liquid is run into the tank through inlets 20 at the top of the tanks, which are provided with gate valves 22. The bleached and washed pulp is drawn off from the tanks through pipes 24 provided with gate valves 26.

The motive power for blowing the charge back and forth between the two tanks is either compressed air or steam depending on whether the materials are to be bleached or boiled. The motive fluid is supplied through a pipe 28 which is provided with a hand valve 30. The pipe 28 has two branches 32 and 34 which lead respectively to riser pipes 36 and 38 on the tanks 4 and 6. The riser pipes 36 and 38 are continued upwardly above the connections of the branch pipes 32 and 34 to provide vents 40 and 42 for the tanks 4 and 6 respectively. The vents are provided with hand valves 44 so that they may be restricted as desired. The branch pipes and 34 and the vents and 42 are opened and closed to admit and exhaust the motive fluid from the tanks by means of diaphragm valves 46, 48, and 52 respectively, which are operated by the same motive fluid which is supplied to them through a small pipe 54. The valves 46 and 52 are normally closed and are arranged to be opened by fluid pressure in the pipe 54, while the valves 48 and 50 operate in a reverse manner, namely, being normally open,

but arranged'to be closed by fluid pressure in the pipe 54. The valves 46 and 52 are shown in section in Fig. 4. The valve stem 56 is normally held raised by the helical spring 58 to close the valve. The valve is opened by the motive fluid entering the diaphragm chamber 59 through the pipe 54 and pressing down upon a thin metallic diaphragm 60. A plate 62 receives pressure from the diaphragm 60 and transmits it to two lever arms 64 which transform a comparatively small downward movement of the plate 62 into a greater movement of the valve stem 56. The valves 48 and 50 are similar to the valves 46 and 52 in general construction, but have the valve and valve seat reversed so that the spring around the valve stem normally holds the valve open and the pressure'on the diaphragm forces down the valve stem to close the valve.

This, of course, necessitates a modification of the valve casing so that the valve and valve stem can be inserted from above,

rather than from below as illustrated in Fig. 4. When there is fluid pressure in the pipe 54, the valves 46 and 52 are opened and the valves 48 and 50 are closed. The motive fluid is therefore admitted to the tank 4, and the motive fluid supply is cut off from the tank 6. The vent of the tank 4 is closed, and the vent of the tank 6 is opened so that the charge which is in the tank4 is blown through the pipe 8 into the top of the tank 6. The check valve 14 in the pipe 10, of course, closes under fluid pressure so that the motive fluid cannot pass through the pipe 10. When there is no pressure in the pipe 54, the operation is reversed, the valves 46 and 52 being closed and the valves 48 and 50 being opened, and the charge is blown through the pipe 10 from the tank 6 into the tank 4. The motive fluid is admitted to and exhausted from the pipe 54 by means of a pilot valve indicated generally by reference numeral 61 which is controlled by mechanism operated by the rise and fall of the liquor levels in the tanks. The valve 61 is shown in detail in Fig. 3. The valve 61 is placed to supply the small pipe 54 with motive fluid drawn from the branch pipe 34 and comprises a coupling 63 in the branch-pipe 34 having a laterally projecting nipple 65 which forms the valve casing. The valve proper 68 is arranged to fit against a valve seat 66 to cut off the flow of mgtive fluid from the pipe 34 to the pipe 54. The valve stem 70 fits loosely in the stem receiving sleeve 71 to provide a passage through which the motive fluid in the pipe 54 is exhausted when the valve 68 is seated against the valve seat 66. The valve 68 is also arranged to seat against the inner end 73 of the sleeve 71 so that. when the valve is open, the leak around the loose valve stem is cut ofl. The valve is opened and closed through a link 76 by means of a lever 74 which projects upwardly from a rock shaft 78 which is journaled through gas tight bearings 80 in the tanks. The right-hand end of the rock shaft 78, as shown in Fig. 1, has a forwardly projecting arm 82 (see Fig. 2) which carries on its forward end a hollow ball 84. The lefthand end of the rock shaft 78 has a rearwardly extending arm 86 which carries a hollow ball 88. When the level of the pulp and liquor mixture in the tank 4 rises to the hollow ball 88, the ball is lifted and the valve 61 is opened admitting the motive fluid to the pipe 54, which operates the diaphragm valves 46, 48, 50 and 52 to blow the charge from the tank 4 into the tank 6. Similarly, after the charge has been blown into the tank 6, the liquor level rises and lifts the ball 54, closing the valve 61 and operating the diaphragm valves, 46, 48, 50 and 52 to blow the charge back from the tank 6 into the tank 4. Test cocks 120 are provided at iaaaeea the ends of the tanks to indicate the height at which the contents of the tanks will lift the hollow balls 84 and 88.

Means are provided for stirring the mixture of pulp and treating liquor during the boiling, bleaching and washing operations and for drawing rags when rags are put into the apparatus. The stirring means comprises two worms 90 in each tank. The

them from cloth into a mass of loose fiber.

worms are mounted on hollow shafts 92 and the two worms in each tank are arranged to be rotated in opposite directions. The hollow shafts 92 are provided with a number of perforations 94 so that water can be admitted to the tanks. The shafts 92 have packed rotary couplings 96 at the outside of the tank so that the shafts may revolve:

and still receive water. One of the shafts in each tank is driven by a connection outside of the tank (not shown) and the two shafts are geared together at one end of the tank by gear wheels 98 so that the other worm is driven from the first worm and in an opposite direction to it. Water can also be admitted into the tops of the tanks 4 and 6 by'means of water connections 99. The worm as a stirrer is particularly useful in the present apparatus since it has no corners to catch and become clogged with rags or pulp and at the same time acts very efficiently as a propeller to stir and beat the charge. in this connection it is to be noted that the ends of the worm 90 merge with the shaft 92 with a gradual radial taper to avoid corners to catch the materials. Moreover, the provision for forcing water through the perforations 94 afford a sure and useful means for loosening any mass of rags or pulp with which the worm may become clogged.

A rotary strainer is provided to draw off the treating liquors and the water used in washing the pulp. The strainer consists of a cylindrical screen 100 mounted on a hollow shaft 101 which is provided with a number of perforations 102 and has an outlet 1.04 which may be closed by means of the gate valve 106. When liquid is being drawn off, the strainer is continually rotated to prevent the pulp from clogging the screen so that the liquid is more easily drained 011'. During the drawing, boiling and bleaching operations, the strainer is stationary since no liquid is drawn off. The strainer is rotated by means of a gear 110 which is loosely splined on the forward end of the strainer shaft 101 and is adapted to he slid in and out of engagement with a driving gear 112 on one of the worm shafts 92.

For the sake of fully describing the different operations of which the apparatus is susceptible, the operation will be described first as a series of operations upon chopped rags including the drawing, boiling and bleaching of the rags to reduce them to.

paper pulp, and then the operation of the apparatus upon pulp which is already reduced to a fibrous condition will be indicated.

The rags to be treated are introduced into one of the tanks through the manhole 19, and hot water is run in until the tank is partially filled with water. Then the worms 90 are rotated to beat the rags and draw After the rags are beaten for a time, the gear 110 is slid into mesh with the gear 112, and as much of the water as possible is drawn off. Then a solution of alkali is introduced into the tank through the pipe .20 until the liquor level in the tank rises to the height of the test cock 120. Then all of the inlet and discharge valves to the tanks are closed and live steam'is admitted into the pipe 28 and the valve 30 is opened.

For convenience in description it will be supposed that the rag drawing operation has taken place in the tank 4 and the alkaline liquor run into the tank 4. The liquor level at "the test cock 1.20 is sufficient to have raised the ball 88 so that the valve 61 is open and the steam passesinto the pipe 54, opening the diaphragm valves 46 and 52 and closing the diaphragm valves 48 and 50. The steam sufliciently to lift the hollow ball 84 andclose the valve 61, to close the diaphragm valves 46 and 52 and open the diaphragm valves 48 and 50, and steam will therefore be directed into the top of'the tank 6 and blow the charge back into the tank 4. The operation of blowing the charge from one tank to another is automatically repeated until the rags are thoroughly treated with the alkali. During the time that the charge is being blown back and forth with the steam the shafts 92 are continuously driven so that the charge is thoroughly mixed and beaten with the alkali in the presence of live steam which fills the tanks. The contact of the rags with the steam materially assists in the action of the alkali in removing the grease, and particularly in discharging the color since the live steam acts chemically on the alkali-saturated rags, assisting the chemical reactions and shortening the time necessary for the alkaline boiling.

The extra water caused by the condensation of the steam in boiling the alkaline so- ;lution may be drawn off from time to time through the strainers 100. After the rag run into this tank through the pipe 99 and drawn off through the pipe 24, the worms 90 and strainer 100 being continuously rotated. After the alkali is Washed from the pulp, the water is drawn off and a solution of chlorid of lime or chemic is introduced through the pipe 20 until the level of the contents of the tank reaches the test cock 120, whereupon the ball 88 is lifted and the pilot valve 60 is opened. The valve 22 is then closed and compressed air under a pressure of about sixty pounds is admitted to the pipe 28 and the valve 30 is opened. The compressed air entering the pipe 54 operates as a motive fluid exactly the same as the steam to actuate the diaphragm valves 46, 48, '50 and 52, to admit compressed air alternately into the two tanks and blow the charge back and forth in bleaching the pulp. During the bleaching operation the valves 44 are partially closed to restrict the vents of the tanks so that when the charge of pulp and bleaching liquor is forced into one tank the air will escape slowly and the pulp and bleaching liquor will fall through a body of compressed air in the tank. During the time that the charge of pulp and bleaching liquor is .being blown back and forth between the tanks, the worms 90 are run to stir the pulp. The pulp is therefore not only exposed to the action of the air in falling into the tanks from the tops thereof, but is also beaten with the bleaching liquor in the presence of the compressed air in the tanks. This secures the most advantageous chemical condition for bleaching, since to obtain a rapid and complete bleach it is necessary not only to saturate the materials with the chemic, but also to aerate the materials. In the present apparatus the materials are thoroughly mixed and saturated with chemic and are also aerated with compressed air. The compressed air is chemically more active in aerating the pulp than air at atmospheric pressure, so that the pressure built up by restricting the vents for the tanks accelerates the bleaching. After the pulp is thoroughly bleached the charge is blown into one of the tanks and the air is turned off. Then wash water is run in through the pipe 99 and drawn off through the discharge pipe 24, the gear 110 being slid into mesh with the gear 112 to rotate the strainer 100 while the wash water is being drawn off from the pulp. After the pulp is thoroughly washed it is drawn off through the discharge pipe 24, air being admitted if necessary into the tank to assist in its-discharge.

While the apparatus has been described as being employed to draw, boil and bleach rags, it is equally applicable for operating on pulp such as wood pulp and the like which has already been reduced to disintegrated fiber. When pulp is to be treated,

the manholes 19 are closed and the charge is run in through one of the tanks through the inlet pipe 20 until the level of the charge in the tank reaches the test cock 120. If it is desired to boil the pulp in alkali the alkapipe 28 and the charge is blown back and forth between the tanks until it is bleached. The illustrated apparatus is capable of carrying out the three operations of drawing rags into pulp, of boiling the pulp in alkali, and of bleaching the pulp. However, a simpler form of apparatus which is designed to carry out but a single one of the above operations or two of them is intended to be within the purview of the present invention.

The term pulp as used in the claims is intended to define fibrous material of which paper is made whether in a finished or in a partially prepared condition, and therefore is intended to include chopped rags and similar materials before they are reduced into a condition of thoroughly disintegrated fiber.

The term liquor as used in the claims is intended to define the various liquids used in the preparation of'pulp such as the water in which rags'are drawn, the alkaline bath in which the pulp is boiled, the bleaching liquor, the wash water, etc.

While the present invention is primarily intended to be used in the preparation of paper pulp, nevertheless it is obvious that it may be used in the preparation of other materials similar to paper pulp, such as cot-- ton hulls for making cellulose, cotton fiber for making gun cotton, etc., and such use is intended to be within the purview of the invention as defined in the claims.

While the preferred embodiment of the invention has been specifically illustrated and described, it is to be understood that the present invention is not limited to the illustrated embodiment, but may be embodied in other constructions within the scope of the invention as defined in the following claims:

1. An apparatus for preparing paper pulp having, in combination, two closed tanks adapted to receive a charge of pulp and liquor, a pipe connecting the bottom of the first tank with the second tank having a valve for preventing the flow of motive fluid from the second tank into the bottom of the first tank, a pipe connecting the bottom of the second tank with the first tank having a valve for preventing the flow iaaaeea 1 of motive fluid from the first tank into the bottom of the second tank, a motive fluid supply, and means acting automatically to admit the motive fluid into the tops of the tanks alternately for blowing the pulp and bleaching liquor back and forth between the two tanks, substantially as described.

2. An apparatus for preparing paper pulp having, in combination, two closed tanks adapted to receive a charge of pulp and liquor, means in each tank for stirring the pulp and liquor, a pipe connecting the bottom of the first tank with the top of the second tank having a valve for preventing the flow of motive fluid from the second tank into the bottom of the first tank, a pipe connecting the bottom of the second tank with the top of the first tank having a valve for preventing the flow of motive fluid from the first tank into the bottom of the second tank, a motive fluid supply, means acting automatically to admit the motive fluid into the tops of the two tanks alternately for blowing the charge of pulp and liquor back and forth between the two tanks, substantially as described.

3. An apparatus for preparing paper pulp having, in combination, two closed tanks adapted to receive a charge of pulp and liquor, a pipe connecting the bottom of the first tank with the top of the second tank having a valve for preventing the flow of motive fluid from the second tank into the bottom of the first tank, a pipe connecting the bottom of the second tank with the top of the first tank having a valve for preventing the flow of motive fluid from the first tank into the bottom of the second tank, a compressed air supply, means acting automatically to admit compressed air into the tops of the two tanks alternately for blowing the charge of pulp and bleaching liquor back and forth between the two tanks, means in each tank for stirring the pulp and liquor, a water supply, means for admitting water to one of the tanks and an outlet from the same tank provided with strainer for retaining the pulp in the tank so that the pulp may be washed in the tank, substantially as described.

4:. An apparatus for preparing paper pulp, having, in combination, two closed tanks adapted to receive a charge of pulp and liquor, a pipe connecting the bottom of the first tank with the top of the-second tank having a valve for preventing the flow of motive fluid from the second tank into the bottom of the first tank, a pipe connecting the bottom of the second tank with the top of the first tank having a valve for preventing the flow of motive fluid from the first tank into the bottom of the second ,tank, a motive fluid supply, means acting wash water outlet for the same tank wash water outlet for the same tank provided with a strainer for retaining the pulp in the tank during the washing operation, substantially as described.

5. An apparatus for preparing paper pulp having, in combination, two closed tanks adapted to receive a charge of pulp and liquor, a pipe connecting the bottom of the first tank with the top of the second tank having a valve for preventing the flow of motive fluid from the top of the second tank to the bottom of the first tank, a pipe connecting the bottom of'the second tank with the top of the first tank having a valve for preventing the flow of motive fluid from the top of the first tank to the bottom of the second tank, a motive fluid supply, means acting automatically to admit the motive fluid into the top of the two tanks alternately for blowing the charge of pulp and liquor back and forth between the two tanks, means in each tank for stirring the pulp comprising a rotatably mounted shaft having a worm carried thereon, a Water supply,

means for admitting water to one of the tanks to wash the pulp in the tank and a rovided with a rotatable drum-like strainer for retaining the pulp in the tank during the washing operation, substantially as described.

6. An apparatus for preparing paper pulp having, in combination, two closed tanks adapted to receive a charge of pulp and liquor, a pipe connecting the bottom of the first tank with thetop of the second tank having a valve for preventing the flow of motive fluid from the top of the second tank to the bottom of the first tank, a pipe connecting the bottom of the second tank with the top of the first tank having a valve for preventing the flow of motive fluid from the top of the first tank to the bottom of the second tank, a motive fluid supply, means acting automatically to admit the motive fluid into the tops of the two tanks alternately for blowing the charge of pulp and bleaching liquor back and forth through the pipe connections between the two tanks, a hollow shaft rotatably mounted in one tank having holes through its periphery and having a worm carried thereon, means for rotating the shaft to stir the pulp, a water supply, connections for admitting water into the hollow shaiit to wash the pulp in the tank and a wash water outlet for thesame tank comprising a rotatable drum-like strainer for retaining the pulp in the tank during the washing operation, substantially as described.

its

7. An apparatus for preparing paper pulp having, in combination, two closed tanks adapted to receive a charge of mixed pulp and liquor, a pipe connecting the bottom of the first tank with the second tank having a valve for preventing the flow of motive fluid from the second tank into the bottom of the first tank, a pipe connecting the bottom of the second tank with the first tank having a valve for preventing the flow of motive fluid from the first tank into the bottom of the second tank, and means aeting automatically to blow the mixture of pulp and liquor back and forth between the tanks comprising a motive fluid supply, a branch pipe from the motive fluid supply to each tank, a vent for each tank, valves in the branch pipes and vents, and mechanism controlled by the rise and fall of the liquor levels in the tanks for operating the valves to admit the motive fluid to one tank, to close the vent of said tank, to cut off the motive fluid from the other tank and to open the vent of said other tank, substantially as described.

8. An apparatus for preparing paper pulp having, in combination, two closed tanks adapted to receive a charge of mixed pulp and liquor, a pipe connecting the bottom of the first tank with the second tank having a valve for preventing the flow of motive fluid from the second tank into the bottom of the first tank, a pipe connecting the bottom of the second tank with the first tank having a valve for preventing the flow of motive fluid from the first tank into the bottom of the second tank, and means acting automatically to blow the mixture of pulp and liquor back and forth between the tanks comprising a motive fluid supply, a branch pipe from the motive fluid supply to each tank, a vent for each tank, air operated dia phragm valves in the branch pipes and vents, and mechanism for operating said valves to admit the motive fluid to one tank, to close the vent of said tank, to cut off the motive fluid from the other tank, and to open the vent of said other tank including a pipe connection between the motive fluid supply and said diaphragm valves, a pilot valve in said connection, and hollow balls in the tanks adapted to be moved by the rise and fall of the liquor level in the tanks to" open and close the pilot valve, substantially as described.

9. An apparatus for preparing paper pulp having, in combination, a tank for receiving a charge of pulp and liquor, and means for stirring and washing the charge comprising a hollow perforated shaft roatablv mounted in the tank, a Worm carried upon said shaft and connections for leading water into the hollow shaft, substantially as described.

10. An apparatus for preparing paper pulp having, in combination, a closed tank adapted to receive a charge of pulp and liquor, and means for stirring and washing the pulp comprising a hollow perforated shaft rotatably mounted in the tank, a worm carried by said shaft, connections for lead ing water into the hollow shaft, and-a rotary strainer for drawing ofl" the liquor from the tank, substantially as described.

11. An apparatus for preparing paper pulp from rags and the like having, in com bination, a tank for receiving a charge of rags and liquor, a rotary worm in the tank for drawing the rags to disintegrate them into a mass of loose fiber, and means for driving the worm, substantially as described.

12. An apparatus for preparing paper pulp from rags and the like having, in combination, a tank for receiving a charge of rags and liquor, a rotary worm located in the tank and near the bottom thereof for drawing the rags to disintegrate them into a mass of loose fiber and means' for driving the worm, substantially as described.

18. An apparatus for preparing paper pulp from rags and the like having, in combination, a tank for receiving a charge of rags and liquor, two rotary worms located side by side in the tank and near the bottom thereof for moving the charge in opposite directions and for drawing the rags to disintegrate them into a mass of loose fiber, substantially as described. I

14. An apparatus for preparing paper pulp from rags and the like having, in combination, a tank for receiving a charge of rags and liquor, a worm for drawing the rags to disintegrate them into a mass of loose fiber, the end of said worm being tapered to avoid sharp corners which would catch the rags, and means for driving the worm, substantially as described. a

15. An apparatus for preparing paper pulp from rags and the like having, in combination, a tank for receiving a charge of pulp and liquor, a rotary shaft extending into the tank, a Worm wound around the shaft for drawing the rags to disintegrate them into a mass of loose fiber, the ends of said worm merging with the shaft with a gradual radial taper to avoid sharp corners which would catch the rags, and means for driving the shaft, substantially as described. EUGENE D. JEFFERSON. Witnesses:

HORACE VAN EVERETT, GEORGE E. S'rEBBINs.

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