US440616A - Method of cleaning the faces of grindstones - Google Patents

Description

(No Model.)

, E. J. BONETT. METHOD OF CLEANING THE PAGES 0P GRINDSTONES. No. 440,616. Patented Nov. 18, 1890.

UNITED STATES PATENT OFFICE.

EDWIN J. BONETT, OF BERLIN, NEW HAMPSHIRE, ASSIGNOR TO HIMSELF, AND THE BERLIN MILLS COMPANY, OF PORTLAND, MAINE.

METHOD OF CLEANING THE FACES OF GRINDSTONES.

SPECIFICATION forming part of Letters Patent No. 440,616, dated November 18, 1890.

Application filed March 10, 1890. Serial No. 343,234, (No model.

T0 at whom, it may concern.-

Be it known that I, EDWIN J. Bonnrr, of Berlin, county of Coos, and State of NewHampshire, a citizen of the United States, have i11- vented a certain new and useful Method of Cleaning the Faces of Grindstones, of which the following is a specification, reference be ing had to the accompanying drawings.

a My invention is especially adapted for the production of wood pulp.

In all operations for producing wood pulp by mechanical disintegration, so far as I am aware, blocks or pieces of wood are held with their faces against the grinding-face of a suitable grinder-such, for instance, as a grindstone or emery-wheel. It has also been customary to prevent injurious heat that would be otherwise produced by friction between the wood and the grinding-surface by keeping the face of the grindstone wet. An objection, however, to this is that after a time the face of the grindstone becomes foul and water is insufficient to keep it clean.

The invention consists in an improved process of cleaning the faces of grindstones generally by directing against their faces a blast of steam. To obtain the best results the steam should not be too dry. \Vhile this method has been in practice found to be especially adapted for use in grinding wood pulp, it may no doubt be used to advantage for other purposes as well.

In the accompanying drawings, Figure 1 is a side elevation, partly in section, of my improved apparatus, Fig. 2, a view of the steamjet pipes detached.

I have illustrated in the drawings a suitable apparatus for practicing my invention; but any suitable means may, of course, be employed.

Referring to the letters of the drawings, A represents a grinder, consisting of a circular grindstone; B B, blocks of wood being ground, and C C, hydraulically-operated presses for forcing the wood against the grinding-faces of the stone. D indicates a steam-pipe communicating at one end with any suitable steam-generator. (Not shown in the drawings.) At the other end it is connected with branch pipes D D, which terminate within the casing or covering E, which surrounds the stone in closed ends provided with numerous perforations, as shown in Fig. 2 of the drawings. These perforations open toward the face of the grindstone, and are located close to it, so that when the pipe D is open for its passage steam is forcibly discharged through the perforations against the face of the stone. I have found it also desirable to prevent the escape of the steam from the cover E, so that the face of the grindstone is kept at a proper temperature, and the heat of the steam acting upon the wood tends to cook and soften it, thereby facilitating the action of the ma chine and producing a better quality of pulp. The blast of steam against the face of the stone, by its force, in connection with its moist and gaseous qualities, cleanse the face of the stone from all impurities. By the use of a liquidsuch, for instance, as watera portion of the dirt accumulating in the face of the stone may be washed away; but it is ascertained by practical use that this is not so efficacious. By the use of water only the heavier and coarser particles of pulp can be cleansed out from the grain of a stone, while the sharp cutting-edges are imperfectly cleaned.

By my invention I am able to so thoroughly cleanse the stone, even when it is'run, as in practice it usually is, at a very high rate of speed, as to produce one-third more wood pulp than where former methods have been employed.

I am aware that it is not new to merely keep the face of the grindstone covered with steam during the process of grinding; but this is clearlydistinguishable from my invention.

\Vhat I claim is The method of cleansing grindstones, which consists in discharging a blast of steam directly against the working-face of the grinder.

In testimony whereof I have hereunto subscribed my name this 5th day of March, A. D. 1890.

EDWVIN J. BONETT.

Witnesses:

ALEX. P. BROWNE, JOHN H. TAYLOR.

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