Improvements relating to Sand-blast Apparatus.
Year: 1899

page_text: Date of Application, 28th Jan., 1899
Complete Specification Lert, 25th Oct., 1899-Accepted, 2nd Dec., 1899
.Improvements relating to Sand-blast Apparatus.
I, JEREMIAH EUGENE MATHEWSON, of Broadheath, in the County of Chester,
Engineer, do hereby declare the nature of this invention to be as follows:-
The sharpening of files," as it is termed, by the sand-blast process, is now
well known, the effect being produced by means of a stream of sand and water,
in the form of liquid mud, projected against the teeth of the file by a jet or jets
of steam, the steam mixing with the liquid mud, after leaving the nozzle.
By this arrangement, however, a loss of velocity in the cutting material
ensues, thereby necessitating an increase in the steam pressure, or otherwise
reducing materially the efficacy of the blast, and thus, in either case, increasing
the cost of working; and it is the object of the present invention to overcome
this objection.
It may be here remarked that the invention is applicable not only to the
sharpening of files, but also to the cleaning of metallic surfaces from scale and
other excrescences.
In carrying out this invention, it is preferred to use compressed air as the
propelling medium, which air may be at the ordinary temperature, or super-
heated in some cases, however, steam may also be used to propel the cutting
material with advantages. Usually, however, the condensation water mixing
with the liquid mud dilutes it to too great an extent, and reduces its cutting
power, whereas, with the compressed air, the working condition is retained for
a much longer period.
The propelling medium & the cutting material are mixed in the proper pro-
portions in a chamber, and the two are carried forward together, so that they
issue at the nozzle at the full velocity, due to the working pressure and tem-
perature.
An equally efficient cutting speed is thus obtained with a considerably lower
working pressure, thus producing a saving of expense.
The apparatus consists of a suitable casing containing a file cutting chamber,
with a hopper for the liquid mud below.
This hopper communicates, by a suitable self-acting valve, with a closed
chamber, which is termed the "seal" chamber, the bottom of which is provided
with another self-acting valve.
From this seal chamber the mud is allowed to flow from time to time into
another hopper, whence it passes to a mixing pipe or chamber.
The seal chamber, hopper, and mixing pipe, are all contained in a compression
chamber of the casing.
The propelling fluid is introduced into this chamber by suitable pipes, and the
outlet is through the mixing pipe or chamber.
A pipe for the propelling fluid projects into the hopper, so that the mud therein
can be agitated from time to time by the fluid.
A similar pipe is also connected with the seal chamber, so that the pressure
inside and outside the chamber may be equalized when required.

page_text: The portion of the casing containing the second hopper is formed of similar
shape, & the mixing pipe or chamber, or outlet, is attached thereto at the apex.
This pipe is bent, and it is provided with a stuffing box containing a rod which
is situated immediately opposite the outlet to the hopper, & by which the outlet
may be cleared, if & when necessary.
This outlet is closed by a valve mounted on a suitable rod, which projects
through the mixing chamber, and has a handle by which the position of the
valve may be changed as and when desired.
The mixing chamber or pipe is connected by means of a flexible pipe with the
nozzle, by which the mud projected onto the surface to be cut or cleaned.
Dated this 28th day of January 1899.
NEWTON & SON,
Agents for the Applicant.
I, JEREMIAH EUGENE MATHEWSON, of Broadheath, in the County of Chester,
Engineer, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described. and ascertained in and
by the following statement:-
The sharpening of files," as it is termed, by the sand-blast process, is now
well known, the effect being produced by means of a stream of "liquid mud,"
composed of fine sand and water, projected at suitable angle against the teeth
of the file by a jet or jets of steam. The steam does not mix with, and therefore
become the propeller of the liquid mud, until after it leaves the orifice or orifices,
at which point the steam attains its greatest velocity. By reason of this non-
mixing, the velocity of the cutting material falls short of that of the steam to
a considerable extent, and consequently it is found necessary, in order to obtain
the requisite velocity of the cutting material, to use steam at a high pressure.
It is the object of this invention to overcome this objection, and otherwise to
increase the efficiency of the apparatus.
It may be here remarked, that the invention is applicable not only to the
sharpening of files, but also to the cleaning of metallic surfaces from scale and
other excrescences by means of liquid mud.
In carrying out this invention, it is preferred, as a matter of convenience, to
use compressed air at the ordinary temperature, or superheated, as the propelling
inedium, but steam may be employed with fairly good results. The objection
to the use of steam is, that the condensation water mixing with the liquid mud,
dilutes it too much, and reduces its cutting power, whereas, with the compressed
air, the working condition of the liquid mud is retained for a much longer
period.
The propelling medium and the cutting material are mixed in the proper pro-
portions in a special chamber, and the two are carried forward together, so that
they issue at the nozzle at nearly the full velocity due to the working pressure
and temperature.
An efficient cutting speed is thus obtained with a considerably lower working
pressure, thus producing a saving of expense.
In the accompanying drawing,
Fig. 1 shows in sectional elevation a file-cutting apparatus as constructed for
the purposes of this invention,
Fig. being a transverse section on the line 1-2 of Fig. 1.

page_text: A is a casing, the upper part of which forms the file-cutting or working
chamber. The bottom of this chamber consists of a hopper B, which is closed
at bottom by a suitable self-acting valve C.
Below this valve is a closed chamber D, which I term the seal chamber,"
the bottom of which is closed by another self-acting valve E.
The hopper B and the seal chamber D, which in form resemble an ordinary
funnel, project into the lower part of the casing A, which is hermetically closed,
and forms what I term the compression chamber." For convenience, I will
give this chamber the reference letter F.
The bottom of this chamber is hopper-shaped, and in it is placed, concen-
trically, another hopper G, into which the liquid mud falls from time to time
through the valve E.
To the bottom of the compression chamber F is connected a mixing pipe or
chamber H, which is connected by a flexible or other pipe J with the file-sharpen-
ing nozzle K, of the usual construction. L represents the file being sharpened.
The flow of the mud to the mixing chamber H from the hopper G, takes place
by gravity, and is regulated by hand by means of the valve M, and immediately
opposite the opening of the hopper G is a clearing rod N, which passes through
a suitable stuffing-box in the walls of the chamber H.
O is the supply pipe for the propelling medium, which pipe enters the com-
pression chamber at its upper part. Connected with this pipe O, is another
pipe P, which extends downwards nearly to the bottom of the hopper G, and lets
in the propelling medium, to stir up or agitate the contents of the hopper from
time to time.
Qis a pipe which connects the seal chamber D) with the compression chamber F
and in the pipe Q is a three-way regulating cock R, so that air or steam may be
let into or out of the seal chamber D, as required.
The liquid mud, after it has operated on the file, falls into the hopper B, from
whence it has to be transferred to the hopper G for reuse.
In order to effect this transfer, which takes place by gravity, the seal chamber D
is required.
The liquid mud is allowed to flow into the seal chamber by removing pressure
from the underside of the valve C. This is effected by moving the three-way
cock so as to place the chamber D in connection with the outer air. Thus, the
pressures in the working chamber A and in the seal chamber D are equalized,
and the valve is free to open, so that the liquid mud can flow into the seal
chamber D.
The valve E is kept closed by the pressure of the air in the compression
chamber F, acting on the underside of the valve.
When the chamber D is full, the valve C has to be automatically closed and the
valve E opened, so that the liquid mud may flow into the hopper G.
This is effected by moving the three-way cock R so as to connect the seal
chamber with the compression chamber, by which means the pressure is equalized
in these two chambers, and the valve E is free to open, while the valve C is
held closed by the pressure underneath it.
The third way of the cock R is to connect the compression chamber F with
the outer air when necessary, the ordinary outlet for the propelling medium being
through the mixing chamber H and pipe J.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what
I claim is:―
1. In the sharpening of files by means of liquid mud propelled by a suitable
propelling medium, the use of an apparatus constructed, arranged, and operating
as herein shown and described.
0 In ennaratus for shornening files and for cleaning metallic surfaces ho

page_text: means of liquid mud" suitably propelled, the combination of a working
chamber, a closed chamber, a compression chamber suitably supplied with pro-
pelling medium under pressure, a mixing chamber, where the cutting material
and the propelling medium come into contact, and which is connected with the
nozzle by a flexible or other pipe, and suitable valves and air supply pipes,,,as
herein shown and described.
3. In apparatus for sharpening files and for cleaning metallic, surfaces, by means
of a "liquid mud," suitably propelled, the combination of a compressing chamber,
a concentric hopper for the liquid mud, having its outlet regulated by a hand-
operated valve; a mixing chamber provided with a cleaning rod, opposite the
outlet of the hopper, all as and for the purpose herein shown and described....
4. In apparatus for sharpening files and for cleaning metallic surfaces by
means of liquid mud" suitably propelled, the use of a mixing chamber wherein
the cutting material, acting by gravity, and the propelling medium,, come to-
gether, and from which they are conveyed to the nozzle without any loss of
velocity, as herein shown and described.
Dated this 25th day of October 1899
NEWTON & SON,
Agents for the Applicant.