US2123211A - Process of saccharification of cellulose - Google Patents

Description

July 12, 1938. H. SCHOLLER 2,123,211

PROCESS OF SACCHARIFICATION OF CELLULOSE Filed Aug. 25, 1934 f5 12 I x 1" 15 2 i I 15 Patented July 12, 1938 UNITED STATES PATENT OFFICE Heinrich Scholler, Solln, near Munich, Germany Application August 25,

1934, Serial No. 741,374

In Germany September 27, 1933 24 Claims.

This invention relates to the sacchariflcation of cellulose with dilute acids. More particularly, the instant invention relates to an. improvement of the process described in the Scholler and Karsch application, Serial No. 498,986, filed November 29, 1930, now Patent No. 1,990,097, whereby a greater yield and higher concentration of sugar is obtained.

Patent No. 1,990,097 inter alia relates to a process of saccharification of cellulose wherein cellulose material is maintained at an elevated temperature and pressure and dilute acids intermittently flowed therethrough at predetermined intervals of time to promote the saccharification reaction and remove the sugar formed. During the intervals between the passage of the acids,

the cellulose material is in a wet, moist or semidry state and the sacchariiication reaction continues.

Decomposition of sugar formed in the aforementioned process is a function of the length of time during which the formed sugar remains exposed to the action of the acid and heat (time of exposure). In the process aforementioned, the

sugar may be removed very rapidly, but this requires large quantities of dilute acid whereby the process is rendered uneconomical.

In the process described previously, the sugar is obtained in the form of a 4% solution and in a quantity up to 80% of the theoretical yield of sugar. The theoretical sugar yield of 100 kgs. of wood amounts to approximately 60 kgs. in round figures, but in practice the yield is approximately 48 kgs. Aside from a small remainder of undecomposed cellulose, the dinerence between theoretical and practical yields (approximately 12 kgs.) is lost through the processes of decomposition. Approximately 6 kgs. are lost through the decomposition of the sugar within the particles of the initial material and the remainder lost on the way through the percolator.

The figures given in the paragraph immediately preceding are not generally applicable and depend among other things on the kind of wood and the size of the particles. The high degree of decomposition within the particles finds its ex lanation in that sugar with the old process required 'a from the particle and reach the flowing stream.

The instant invention contemplates shortening the time of exposure in such a manner whereby it is unnecessary to increase the quantity of liquid and also the rapid and careful removal of the sugar.

The shortening of the time of exposure,

accordcomparatively long time to diffuse ing to the principles of the instant invention, is secured by repeated and periodic increase and/or decrease of temperature and/or pressure with or without changes in the acid concentration, and also the choice of a favorable proportion between the time of exposure and the total time of reaction.

The nature and object of the instant invention will become more apparent from the following description, appended claims and accompanying drawing, wherein the figure illustrates a view, partly in section, of the lower portion of a percoiator. i

In carrying out the process of the instant invention, cellulose material is introduced in a percolator and preferably compressed therein. While the cellulose material is being heated under pressure, batches of dilute acid solution are intermittently introduced at the top of the percolator and flowed into and out of the cellulose material to promote the saccharification reaction and re- .move the sugar formed. In the intervals between the passages of acid, the cellulose material is in a wet, moist or semi-dry state, but the saccharification reaction continues. This procedure is more fully explained in application Serial No. 498,986.

As above explained, in the process described in Patent No. 1,990,097, the cellulose material is periodically at rest in the half-moist state and surrounded by vapors. In the pores of the cellulose particles there is naturally present more or less moisture which is retained by capillary forces.

I have found that a simple but very effective way of shortening the time of exposure of the sugar and increasing the sugar yield consists in the use of comparatively cold batches of dilute acid. If a batch of liquid flows at a very low temperature, for example 10 to 20 degrees below the temperature of the cellulose material, through the percolator, there occurs within the range of the batch of liquid, and especially below the batch of liquid, a decrease or temperature and pressure which causes steam to develop in the capillaries of the particles. The steam expels the liquid from the particles. Thus, the sugar present in the particles is very quickly removed from the interior thereof and reaches the batch or liquid which transports it from the reaction vessel. The batch of liquid, being under a higher pressure, can then again enter the capillaries.

I have also found that the cold batches of the liquid ailord the additional advantages of nowing in a comparatively compact manner and with comparatively great speed. The flow of the ance with the instant invention may be accelerated by applying pressure thereto from above, for example, with steam having a higher temperature than the cellulose material and, therefore, also a higher pressure than that previously present in the percolator. The increase in pressure caused by the steam when it is introduced, as just explained, may be approximately 2 atmospheres. In this way, it is possible to force the batch of liquid through a layer of compressed cellulose material having a height of 10 m. in a few minutes.

The use of cold batches of liquid and the added pressure by means of steam, above described, tend to impart to the upper part of the percolator a temperature higher than the temperature in the lower portion of the percolator. Such an operation would result in the reaction in the upper part of the percolator taking place at a greater rate than in the lower part, with the consequence that an unequal disintegration impairing the total result would be secured. In order to eliminate this detect, the invention also contemplates blowing in steam from below during the period of rest. The steam may be introduced in the lower portion of the percolator in any convenient manner, such as, for example, through a suitable steam range on the lower cone of the percolator or through the filter itself.

The introduction of steam from below is preferably continued while the batch runs into the upper part of the percolator. As a result, at first the batch of liquor cannot enter into the material since this is prevented by the steam meeting the batch of liquor. As soon as the whole batch of liquor is introduced into the percolator, the introduction of steam from below is stopped and steam is introduced from above, as previously described, whereby the acid is caused to flow through the percolator.

In addition to the change of temperature and pressure, as above explained, a change in acid concentration may be also used to advantage.

If aqueous solutions of acid are used and the acid concentration thereof is considerably lower in the lower part of the percolator than in the upper part of the percolator, the weak acid functions to remove the sugar, while the stronger acid solution largely adheres to-the material and causes the sacchariflcation reaction to continue during the rest period. The weak acid solution portion of the following batch then meets the material that has absorbed the stronger acid of the preceding batch and the higher concentration potential created thereby between the liquid in the particles, and the liquid outside the particles is favorable to the removal of the sugar from the particles.

Another advantage which the use of batches of unequal acidity ofiers when employed in the manner just mentioned is the saving of acid, since the sugar is removed with that part of the batch which is poor in or free from acid. Therefore, the speed of the reaction is essentially determined by the acid concentration of the batch which largely adheres to the material.

The employment of different acid concentrations may be utilized in such a manner that the acid content of the batches is increased. In other words, each succeeding batch may have an acid concentration higher than that of the preceding batch. A preferred embodiment contemplates the use of comparatively low concentra- 'batch of liquid through the percolator in accordtion acids at the beginning with correspondingly higher temperatures.

The two expedients, i. e. the use oi. batches having an unequal concentration and the use of batches with increasing acid content, may be used simultaneously. Instead of one batch, the acid content of which is higher in the upper part than in the lower, there may, of course, be used two batches, the first of which is poor in or free from acid, while the second is rich in acid, the two batches following each other at short intervals. The gradual increase of acid concentration replaces entirely or partially the increase oi temperature of the process described in application Serial No. 498,986.

I have found that by raising the factors in the reaction, 1. e. temperature and acid concentration, the sugar solution formed is approximately of a constant concentration or gradually becomes lower. For instance, it is expedient at the beginning of the process to keep the sugar concentration around 7% and gradually decrease it to 3% in the course 01 the process. Then suddenly, at the end of the process, the concentration drops to nothing, which indicates that the reaction is at an end.

The batches of aqueous acid solution used in accordance with the previously-described process must be in a certain proportion to the size of the fill. I have found it expedient to use at the beginning an especially large batch, the size of which also depends on the moisture of the material. In the case of the first batch, a ton of dry wood substance should meet about 1 cbm. of liquid. The batch may be larger or smaller, depending upon whether the material is dry or moist. The subsequent batch may be two-thirds of the first batch. In the course of the process, the batch may be made continuously smaller, approximately in the same proportion as the fill of the percolator is diminished in volume by reason of the saccharification of the cellulose and the removal of the sugar. The interval between the smaller batches towards the end of the process may also become shorter.

In the instant invention, applicant contemplates performing subsequent hydrolysis to form glucose by retarding the cooling.

The sugar solutions prepared in accordance with the present process have the peculiarity that subsequent hydrolysis is very effective in the first fractions, declines in the middle fractions, and is less successful in the final fractions. The subsequent hydrolysis is, therefore, carried out with advantage, especially with the first fractions. Subsequent hydrolysis may be efiected in the lower part of the percolator by leaving the batch therein for a short time, say 30 minutes, at about 155 C. in the presence of 0.4% sulphuric acid.

Another procedure consists in withdrawing the liquid that is to be subsequently hydrolyzed from the percolator, cooling it to 100C and keeping it in this state in ordinary containers, for example, wooden vats. It is found that about the first tenth of the sugar obtained by means of decomposition requires, at 90 C.-100 C. and with a 0.4% concentration of sulphuric acid, a subsequent hydrolysis of about 24 hours, while in the case of the second and third tenths, there suffices a period that is shorter by several hours for each case. Obviously, the periods of the subsequent hydrolysis depend greatly on the temperature and also on the acid concentration. They are approximately in simple inverse proportion to the concentration oi. acid.

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The subsequent hydrolysis may also take place in separate containers under pressure at temperatures above 100 C., for instance, by heating for 1 hour at 145 C. with an acid concentration of 0.4% sulphuric acid.

As previously explained, the subsequent hydrolysis is particularly advantageous with the first half of the sugar formed in the process. No important gain is secured by hydrolysis of the second half of the formed liquid. It may even be harmful. Consequently. the subsequent hydrolysis is confined to the first half of the sugar obtained.

After completion of the subsequent hydrolysis, neutralization, filtration and the cooling of the wort may take place immediately. The cooling of the wort may be carried out in the known manner by, for example, means of heat exchange with fresh water for the percolation.

I have found by my investigations that the harmful decomposition of the sugar is a function of the ratio between the time of exposure of the sugar and the total reaction of the cellulose. By practical operation. I have determined that absolute time of exposure of the sugar cannot be shortened at will. It has a natural maximum. Thus, the speed with which the sugar is removed from the particles and the percolator has natural limits. Experience has shown that by using judicious conditions of reaction (low temperature and acid) to permit the process to go on at so slow a. rate that the time of reaction is more than 12 hours. The ratio between the time of exposure and the total reaction time is thereby made more favorable and the yield higher.

Another procedure of shortening the time of exposure of the sugar within the particles consists in the use of short-fiber material. When wood waste, such as shavings, etc., is not used, and logs. sticks and the like are cut up, it is expedient to cut the wood across the grain into small pieces, with short fibers of a length of a few millimeters only, the pieces having a diameter of 1 to 2 cm. When introduced into the percolater, these plates assume a horizontal position. the fibers being more or less vertical and in a position to be easily penetrated by the liquid flowing through the percolator. ,This shortens the intraparticular time of exposure.

Referring now to the drawing, wherein like reference numerals designate like parts, the reference numeral I designates a percolator of the common type having at the upper portion thereof means to supply the cellulose material and means to supply the dilute acids, as well as means to introduce steam. Since these features are well known, they have not been illustrated in the drawing. In the lower part of the percolator, there is provided means to introduce steam into the lower portion of the percolator. In the form illustrated, this means consists of an annular member 2, mounted in any convenient manner between the end of the percolator 3 and the closure 4. The ring 2 is provided with a continuous channel 5 which communicates with orifices 6 to form a nozzle-like structure directing any steam supplied thereto to the interior of the percolator. The steam is supplied from a suitable source of supply (not shown) by the feed pipe I and is controlled by the valve 8.

It is also expedient to use for the purpose of steaming, besides the device previously mentioned, the filter arranged in the cone of the percolator, because this offers at the same time the advantage of cleaning thefilter. The filter conlets I2 may be provided.

sists of acid-proof, porous filter stones made of granulated material, stone, resin or the like. The stones or bricks are made so that the smallest openings are on the inside. These filter stones lie on the layer I which serves as a lining for the percolator. To prevent the filter stones from lying solidly on the lining II], it is advantageous to provide grooves or channels II. If desired, the lining may be made smooth, and the filter stones provided with raised parts. or a network may be arranged between them. This offers the advantage of easy passage for the steam which enters between the lining I0 and the filter stones 9. It also offers the additional advantage that the acid passing through the filter stones easily finds its way to the outlet.

Underneath the filter stones, there are provided openings I2 to which pipes I3 are connected leading to an annular pipe I4. The pipe I4 is connected to an outletpipe I5. A pipe I5 is also connected to the annular pipe structure I4. The pipe I6 is provided with a stop valve I! by means of which steam may be introduced into the pipe I6, and hence into the pipe I4, thence into the pipe I3, through the outlet I2, and into the interior of the cone. If desired, several out- The drawing shows one illustrative embodimentutilizing a plurality of such outlets.

In the outlet connection I5, there is provided an observation device I8 whereby one can ascertain whether acid liquid flows from the percolator and also to determine when the steam should be introduced. This observation device may, if desired, be also or alternatively provided in the pipes I3. As the sugar wort tends to obscure the observation glasses and make them nontransparent, it is preferred to provide glass insertions I9 projecting into the interior of the pipe I5 which are continually washed by the wort flowing through said pipe in a manner to keep the glasses clean.

In actual practice, when the person watching at the observation point I8 has convinced himself that no more acid wort or no more batches flow from the percolator, either the valve 8 may be opened or, if both devices are provided, the valves 8 and I7. The steam entering at 8 will then fiow from the foot of the percolator and pass out of the nozzle 6 into the interior of the percolator while the steam coming from the pipe IE passes through the annular pipe I4, the pipes I3, the openings I2, and through the filter stones 9, distributing itself through the channels II over the entire surface of the cone, penetrating the filter stones, and cleaning them at the same time during its passage to the interior of the percolator.

The process can be applied to all kinds of cellulose material, thus to wood, peat, etc. It may also be carried out with any desired acids and mixtures of acids as long as the acid solution has a sufficient concentration of hydrogen ions.

An illustrative example of the carrying out of the process with the arrangement that has been shown and with a percolator having a content of 20,000 liters is hereafter set forth:

Arrangement-Size of percolator: 20,000 liters content. The percolator is of the type described in Patent 1,990,097, modified as herein described.

Uscd:-5,000 kgs. of dry wood substance. 50 cbm. of water, 400 kgs. of 50% sulphuric acid (50 ohm. 0.4% sulphuric acid).

Test c0nditions:-Running-1n time is 5 minutes, running-off time and pause in working are Percent Reducing sugar 5.3 Fermentable sugar 4.3

Since it is obvious that various changes and modifications may be made in the above description without departing from the nature or spirit thereof, this invention is not restricted thereto except as set forth in the appended claims.

I claim:

1. A process of sacchariflcation of cellulose which comprises heating cellulose under pressure in a percolator, intermittently flowing batches of dilute acid at predetermined intervals through said cellulose, and periodically changing the temperature and pressure conditions to cause steam to develop in the capillaries oi the cellulose and expel the liquid therefrom.

2. A process of sacchariflcation of cellulose which comprises heating cellulose under pressure in a percolator and intermittently flowing batches of dilute acid at predetermined intervals through said cellulose, acid batches being of a temperature lower than the cellulose to be treated therewith whereby a decrease in the temperature and pressure of the cellulose in the range of the acid is secured.

3. A process of sacchariflcation of cellulose which comprises heating cellulose under pressure in a percolator, intermittently flowing at predetermined intervals batches of dilute acid of a temperature lower than the cellulose through said cellulose, said acid batches being of different concentrations and a lower temperature than the cellulose to be treated therewith,-and applying pressure to accelerate the flow of the acid batches through the cellulose.

4. A process of sacchariflcation of cellulose which comprises heating cellulose under pressure in a percolatcr, intermittently flowing at predetermined intervals batches of dilute acid through said cellulose, said acid being of a temperature lower than that oi the cellulose, and increasing the temperature of the cellulose in the lower portion of the percolator at least before introducing a batch of acid.

5. A process of sacchariflcation of cellulose which comprises heating cellulose under pressure in a percolator, intermittently flowing at predetermined intervals batches of dilute acid through said cellulose, said acid batches being of a temperature lower than the cellulose to be treated therewith, and introducing steam in the lower portion of the percolator at least prior to the introduction of a batch of acid.

6. A process of sacchariflcation of cellulose which comprises heating cellulose under pressure in a percolator, intermittently flowing at predetermined intervals batches of dilute acid through said cellulose, said acid batches being of different concentrations and a lower temperature than the cellulose to be treated therewith, applying steam after the introduction of a batch of acid to accelerate the flow through the cellulose, and introducing steam in the lower portion of the percolator at least prior to the introduction of a batch of acid.

'1. A process of sacchariflcation of cellulose which comprises heating cellulose under pressure and intermittently flowing batches of dilute acid of diiierent concentrations through said cellulose to produce a sugar concentration which at the beginning is approximately 7%.

8. A process of sacchariflcation of cellulose which comprises heating cellulose under pressure and intermittently flowing batches of dilute acid of difierent concentrations through said cellulose to produce a sugar concentration which at the beginning is approximately 7%, the acid concentration of the successive batches being increased.

9. A process of sacchariflcation of cellulose whichcomprises heating cellulose under pressure and intermittently flowing batches of dilute acid of different concentrations through said cellulose to produce a sugar'concentration which is constant or gradually decreases, the quantity of the batches of acid being decreased in the course of the process approximately in correspondence with the shrinkage of the cellulose.

10. A process of saccharification of cellulose which comprises heating cellulose under pressure and intermittently flowing batches of dilute acid of different concentrations through said cellulose to produce a sugar concentration which is constant or gradually decreases, the acid concentration of the successive batches being increased, the quantity of the batches of acid being decreased in the course of the process approximately in correspondence with the shrinkage of the cellulose.

- 11. A process of sacchariflcation of cellulose which comprises heating cellulose under pressure and intermittently flowing batches of dilute acid of different concentrations through said cellulose to produce a sugar concentration which is constant or gradually decreases, the quantity of the batches of acid being decreased in the course of the process approximately in correspondence with the shrinkage of the cellulose, and the time intervals being decreased.

12. A process of saccharification of cellulose which comprises heating cellulose under pressure and intermittently flowing batches of dilute acid r of different concentrations through said cellulose to produce a sugar concentration which is con-'- pressure, and additionally treating the sugar solution with acid in the lower part of the percolator.

14. A process of sacchariflcation of cellulose which comprises heating cellulose under pressure in a percolator, intermittently flowing batches of dilute acid at predetermined intervals through said cellulose, the acid being at a temperature lower than the cellulose whereby a decrease in the temperature and pressure of the cellulose in the range of the acid is secured, and additionally treating the sugar solution with acid in the lower part of the percolator.

15. A process of saccharification of cellulose which comprises heating cellulose under pressure in a percolator, intermittently flowing batches of dilute acid at predetermined intervals through said cellulose, periodically changing the temperature and/or pressure during the heating under pressure, and additionally treating the first half of the sugar solution with dilute acid for several hours at 70 C. to 100 C., the concentration of the acid and the time depending on the temperature used.

16. A process of saccharification of cellulose comprising heating cellulose under pressure in a percolator, intermittently supplying to the percolator at predetermined intervals batches of dilute acid to flow through said cellulose, the temperature of said acid batches being lower than that of the cellulose, inhibiting the flow of the acid batches through the cellulose until the whole thereof has been introduced, and thereafter applying pressure to cause the acid batches to flow through the cellulose.

17. A process of saccharification of cellulose comprising heating cellulose under pressure in a percolator, intermittently supplying to the percolator at predetermined intervals batches of dilute acid to flow through said cellulose, the temperature of said acid batches being lower than that of the cellulose, introducing steam in the lower portion of the percolator at least before introducing a batch of acid to increase the temperature of the cellulose in the lower portion of the percolator and inhibit the flow of the acid batches through the cellulose until the whole thereof has been introduced, and thereafter supplying steam of a temperature higher than the temperature of the cellulose to cause the acid to flow through the cellulose.

18. A process of saccharification of cellulose comprising heating cellulose under pressure in a percolator, intermittently supplying to the percolator at predetermined intervals batches of dilute acid to flow through said cellulose, the temperature of said acid batches being lower than that of the cellulose, increasing the temperature of the cellulose in the lower portion of the percolator at least before introducing a batch of acid, inhibiting the flow of the acid batches through the cellulose until the whole thereof has been introduced, and thereafter supplying steam of a temperature higher than the temperature of the cellulose to cause the acid to flow through the cellulose.

19. A process of saccharification of cellulose comprising heating cellulose under pressure in a percolator, intermittently supplying to the percoletor at predetermined intervals batches of dilute acid of difierent concentrations to flow through said cellulose, the acid concentration of the successive batches being increased and the temperature of said acid batches being lower than that of the cellulose, inhibiting the flow of the acid batches through the cellulose until the whole thereof has been introduced, and thereafter applying pressure to cause the acid batches to flow through the cellulose.

20. A process of saccharification of cellulose comprising heating cellulose under pressure in a percolator, intermittently supplying to the percolator at predetermined intervals batches of dilute acid of different concentrations to flow through said cellulose, the acid concentration of the successive batches being increased and the temperature of said acid batches being lower than that of the cellulose, introducing steam in the lower portion of the percolator at least before introducing a batch of acid to increase the temperature of the cellulose in the lower portion of the percolator and inhibit the flow of the acid batches through the cellulose until the whole thereof has been introduced, and thereafter supplying steam of a temperature higher than the temperature of the cellulose to cause the acid to how through the cellulose.

21. A process of saccharification of cellulose comprising heating cellulose under pressure in a percolator, intermittently supplying to the percolator at predetermined intervals batches of dilute acid of different concentrations to flow through said cellulose, the acid concentration of the successive batches being increased and the temperature of said acid batches being lower than that of the cellulose, increasing the temperature of the cellulose in the lower portion of the percolator at least before introducing a batch of acid, inhibiting the flow of the acid batches through the cellulose until the whole thereof has been introduced, and thereafter supplying steam of a temperature higher than the temperature of the cellulose to cause the acid to flow through the cellulose.

22. A process of saccharification of cellulose comprising heating cellulose under pressure in a percolator, intermittently supplying to the percolator at predetermined intervals batches of dilute acid of different concentrations to flow through said cellulose, the acid concentration of 'dilute acid of difierent concentrationsto flow through said cellulose, the acidconcentration of the successive batches being increased and the quantity of each successive batch of acid being decreased approximately in correspondence with the shrinkage of the cellulose, the temperature of said acid batches being lower than that of the cellulose, introducing steam in the lower portion of the percolator at least before introducing a batch of acid to increase the temperature of the cellulose in the lower portion of the percolator and inhibit the flow of the acid batches through the cellulose until the whole thereof has been introduced, and thereafter supplying steam of a temperature higher than the temperature of the cellulose to cause the acid to flow through the cellulose.

24. A process of saccharification of cellulose comprising heating cellulose under pressure in a percolator, intermittently supplying to the percolator at predetermined intervals batches of dilute acid of different concentrations to flow through said cellulose, the acid concentration of the successive batches being increased and the quantity of each successive batch of acid being decreased approximately in correspondence with the shrinkage of the cellulose. the temperature of said acid batches being lower than that o! the cellulose, increasing the temperature of the cellucellulose until the whole thereof has been introduced, and thereafter supplying stem of a. temperature higher than the temperature of the cellulose to cause the acid to how through the cellulose. 5

5 lose in the lower portion of the percolator at HEINRICH SCHOLLER.

least before introducing a batch of acid, inhibiting the flow o! the acid batches through the IGER'I'IHGATE 0F connscrrou. Petent No. 2,12 ,311. July 12,-- 1958..

1331311103 scnorma.

Itiiaherehy" certified that error appears inthe printed specification of the above nunib e'redpatent requiring correction as follows: Page 1 first co11mn,.'ll.ne 5 e1aim2,'be'fore the'word "acid" insert Bailey-and that the 5am. Letters Patent ahouldbe ma rd'th this correction thereingthet. the same may conform to the record of the case inthe Patent Officer Signed and sealed this'lth day of August, A. n. 19

Leslie Frazer (Seal) Acting Commissioner of Patents.

decreased approximately in correspondence with the shrinkage of the cellulose. the temperature of said acid batches being lower than that o! the cellulose, increasing the temperature of the cellucellulose until the whole thereof has been introduced, and thereafter supplying stem of a. temperature higher than the temperature of the cellulose to cause the acid to how through the cellulose. 5

5 lose in the lower portion of the percolator at HEINRICH SCHOLLER.

least before introducing a batch of acid, inhibiting the flow o! the acid batches through the IGER'I'IHGATE 0F connscrrou. Petent No. 2,12 ,311. July 12,-- 1958..

1331311103 scnorma.

Itiiaherehy" certified that error appears inthe printed specification of the above nunib e'redpatent requiring correction as follows: Page 1 first co11mn,.'ll.ne 5 e1aim2,'be'fore the'word "acid" insert Bailey-and that the 5am. Letters Patent ahouldbe ma rd'th this correction thereingthet. the same may conform to the record of the case inthe Patent Officer Signed and sealed this'lth day of August, A. n. 19

Leslie Frazer (Seal) Acting Commissioner of Patents.

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