US1560881A - Quick-cook sulphite process - Google Patents

Description

Patented Nov. 10, 1925.

UNITED STATES PATENT OFFICE.

PHILLIP C. ULMEN, OF RIVER ROUGE, AND HERMAN H. BECKER AND RUSSELL '1. MANN, OF DETROIT, MICHIGAN.

QUICK-COOK SULPHITE PROCESS.

Application filed April 14, 1924. Serial No. 706,542.

To all whom it may concern:

Be it known that we, PHILLIP C. ULMEN, a resident of River Rouge, county of Wayne, and State of Michigan, and HERMAN H. BECKER and RUssELL T. MANN, residents of Detroit, county of \Vayne, and State of Michigan, all citizens of the United States of America, have invented certain new and useful Improvements in Quick-Cook Sulphite Processes, of which the following is a full and clear specification.

- Our invention relates to the well-known quick-cook 'sulphite pulp processes, and the object is to so discharge the contents of the digester as to preserve the strength of the fiber, as more fully hereinafter set' forth.

The drawing is a diagram of a digester of ordinary construction equipped to carry out our invention.

In our preferred construction, we provide for a supply of cold water (preferably white water) under pressure through a supplypipe 1, which is connected to a 'vertical branch 2 arranged alongside the digester. The branch-pipe 3 leads from the pipe 2 into the digester at the upper end thereof, this pipe being provided with a valve 4 and at its inner end with a strainer 5.

Duplicate pipes 6 and 7 enter the lower part of the digester, the ends within the digester being covered by strainers 8. The outer ends of these pipes empty into the usual large blow-off conduit 9 provided with the usual blow-ofi valve 10. Each of opening the the pipes 6 and 7 is provided with a pair of valves 11 and at a point between each pair of valves each pipe is connected by a branch 12 with the lower end of the pipe, 2, a valve 13 being provided in the pipe 2 at a point between branch-pipes 12 and the main supply-pipe 1.

After the digesting process is completed and the digester is ready to be discharged, we do not follow the usual practice of first contrary, proceed as follows: We first open the valves 11 and the valve 4, whereby the spent liquor is discharged into the blow-off pipe 9 and thence to the usual blow-pit, and

blow-off valve 10, but, on the at the same time a supply of fresh cold water is admitted at the top of the digester. In this way, the pressure is quickly reduced, the temperature is likewise reduced and practically all the spent liquor is run off into the pit. We then close the two outer valves 11 and leave one or both of the inner valves 11 open, preferably one; we likewise open valve 13;. then fresh cold water enters the digester at the bottom through one or both of the strainers 8, while at the same time the water continues to flow in through the strainer 5 at the top; the main blow-off valve 10 is likewise opened. This results in the washing out of the cooked chips through the main blow-off valve into the pit, as

usual.

Our process has the advantage that it avoids the bursting ofthe chips that results from, the present usual method of discharging quick-cook digesters. This bursting of the chips results from thesudden release of the pressure through the usual blow-off valve. The steam, as is well known, cells of the wood suddenly expands, when thus released, with the result that a considerable' portion of the chips is exploded and the fibers are destroyed or injured. With our method, the introduction of the cold water and simultaneous running off of the spent liquor quickly reduces pressure and temperature without affecting the-original full formof the chips, thus greatly increas- 1n of the fact that the chips are discharged in practicall their original form, we subsequently disintegrate the chips by means 'ogfa suitable machine, which operation is a s mple and inexpensive one and is fully comin the the strength of the pulp fiber. In view pensated for by the increased strength of the pulp we get. Inpractice, we have succeeded in producing pulp whlch is nearly as strong as that obtaine by means of the longer. Mitscherlich method, and we have as possible and thus insure the cold water being quickly distributed throughout the digester.

What we claim as newis:

The method of discharging quick-cook sulphite digesters consisting in straining oil? the spent liquor and simultaneously inject ing cold water to thus quickly reduce the temperature and pressure within the digester, and then, after the temperature and .1

pressure have been thus reduced, washing out the cooked chips. In testimony whereof we hereunto aflix our signatures this 31" day of March 1924.

PHILLIP o. ULMEN. HERMAN H. BECKER. RUSSELL T. MANN.

Images