IMPROVEMENTS IN THE SAND BLAST PROCESS AND IN APPARATUS EMPLOYED IN THE SAID PROCESS to be as follows:
Year: 1886

page_text: Employed in the said Process.
We JOHN BENJAMIN STONE trading as Stone Fawdry and Stone of the Union
Glass Works Dartmouth Street Birmingham in the County of Warwick Glass
Manufacturer and FREDERICK WILLIAM HINDSON of N° 95 Scholefield Street
Birmingham aforesaid Glass Mould Maker do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE SAND BLAST PROCESS AND IN
APPARATUS EMPLOYED IN THE SAID PROCESS to be as follows:-
"
In the ordinary methods of conducting the sand blast process the stream of sand
is projected by a jet of air produced by a fan or by a jet of steam.
In conducting the sand blast process according to our invention we dispense
with a fan or steam jet and employ condensed or compressed air stored in a strong
reservoir for the propulsion of the sand. This condensed air is allowed to escape
from the reservoir through a pipe in which the sand is allowed to fall or into
which it is drawn by the current of condensed air and is carried by the said
current of condensed air to the surface to be operated upon.
The apparatus we employ consists of a strong reservoir made preferably of
wrought iron. In this reservoir air is condensed by means of a condensing pump
we do not limit ourselves to any particular pressure of the air in the said reservoir
but we find in practice a pressure of forty pounds on the square inch to start with
answers very well and the process may be carried on until the pressure of the air
is reduced to three or four pounds on the square inch. The reservoir may be
provided with a Bourdon or other pressure gauge to indicate the pressure of the
air in condensing it and as it is reduced in the course of working.
The sand is contained in a hopper or other vessel from which it descends or
is drawn into a pipe conducting a current of condensed air to the surface to be
opereted upon. The sand is carried forward by the current of air and projected on
the surface to be operated upon. The pressure of the air in the condenser at the
commencement of the process is much greater than is necessary for effecting the
operation but gradually diminishes as the air escapes In practice it is necessary
or desirable to have a jet of air of approximately uniform pressure. For the
purpose of securing this condition we employ a regulator by which the flow of the
D

page_text: air is maintained at an approximately uniform pressure. The regulator described
and represented in the specification of Letters Patent granted to Alexander
Melville Clark dated the 29th day of November, 1883 N° 5571 may be conveniently
employed but we do not limit ourselves to the use of any particular regulator as an
intelligent workman may effect the regulation of the blast with sufficient nicety
by the use of an ordinary stopcock situated in the pipe conducting the current of
condensed air.
In order to increase the efficiency of the condensed air it may be heated and its
elastic force increased. To effect this the reservoir after the air has been con-
densed in it may be heated either by the direct application of a source of heat to
the reservoir or by the introduction of steam into a steam jacket surrounding the
reservoir.
1000

page_text: Employed in the said Process.
. U
We JOHN BENJAMIN STONE trading as Stone, Fawdry and Stone of the Union
Glass Works, Dartmouth Street Birmingham in the County of Warwick, Glass
Manufacturer and FREDERICK WILLIAM HINDSON of N° 95 Scholefield Street,
Birmingham, aforesaid, Glass Mould Maker do hereby declare the nature of the said
Invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
L
'+1'
In the ordinary methods of conducting the sand blast process the stream of sand
is projected by a jet of air produced by a fan or by a jet of steam.
In conducting the sand blast procéss according to our invention we dispense
with a fan or steam jet and employ condensed or compressed air stored in a strong
reservoir for the propulsion of the sand. This condensed air is allowed to escape
from the reservoir through a pipe in which the sand is allowed to fall or into which
it is drawn by the current of condensed air and is carried by the said current of
condensed air to the surface to be operated upon.
The apparatus we employ consists of a strong reservoir made preferably of
wrought iron. In this reservoir air is condensed by means of a condensing pump.
We do not limit ourselves to any particular pressure of the air in the said reservoir
but we find in practice a pressure of forty pounds on the square inch to start with
answers very well and the process may be carried on until the pressure of the air
is reduced to three or four pounds on the square inch. The reservoir may be
provided with a Bourdon or other pressure gauge to indicate the pressure of the
air in condensing it and as it is reduced in the course of working,
I
The sand is contained in a hopper or other vessel from which it descends or is
drawn into a pipe conducting a current' of condensed air to the surface to be
operated upon. The sand is carried forward by the current of air and projected
on the surface to be operated upon.
.
I
+47
The pressure of the air in the condenser at the commencement of the process is
much greater than is necessary for effecting the operation but gradually diminishes
as the air escapes.
In practice it is necessary or desirable to have a jet of air of approximately
uniform pressure. For the purpose of securing this condition we employ a regu-
lator by which the flow of air is maintained at an approximately uniform pressure.
The regulator described and represented in the specification of Letters Patent
granted to Alexander Melville Clark dated the 29th day of November 1883,
N° 5571, may be conveniently employed; but we do not limit ourselves to the
use of any particular regulator as an intelligent workman may effect the regulation
of the blast with sufficient nicety by the use of an ordinary stopcock situated in
the pipe conducting the current of condensed air.
Figure 1 of the accompanying Drawings represents in elevation the condensing
pump or compressor and the reservoir in which the air is condensed or com
pressed and Figure 2 represents in elevation the apparatus to which the condensed
!
"

page_text: or compressed air is conducted and in which apparatus the sand blast process is
performed upon the articles; Figure 3 represents in vertical section and Figure 4 in
horizontal section the apparatus Figure 2 drawn to a larger scale; Figures 5, 6 and
7 represent parts of the said apparatus.
The same letters of reference indicate the same parts in the several Figures of
the Drawings.
a is the air condensing pump or compressor worked by the crank rod 6 of a
steam engine or other motive power engine and c is the reservoir in which the air
is condensed or compressed by the condensing pump a the said air being condensed
by preference to a pressure of about forty pounds on the square inch; c³ is a spring
safety valve to limit the pressure of the air condensed in the reservoir c; ³ is a
pipe at the bottom of the reservoir c having a stop cock (not represented in the
Drawing). Any water condensed in the reservoir c may be drawn off by the stop
cock of the pipe o³.
The condensed air from the reservoir c is conveyed by the main pipe d to branch
pipes in connection with the several chambers in which the sand blast process is
being conducted. One of these branch pipes is marked e and is in communication
with the chamber f. On the said pipe e is a Bourdon or other gauge for indicating
the pressure of the condensed air in the said pipe. The bottom of the chamber f
is conical and opens into the top of the hopper 9 containing the sand used in the
process, the said hopper being in communication by means of the sand conducting
pipe with the blast pipe e. The junction of the sand pipe h with the blast pipe e
is represented in end elevation in Figure 5 and sections taken at right angles to
one another in Figures 6 and 7. The blast pipe e opens into the top of the sand
pipe by the nozzle i at one side, the delivery pipe e' opening by a conical mouth
at the other side (see Figure 6), the interior of the delivery pipe e³ being by
preference grooved with a helical groove as represented. By means of the exhaust
produced in the sand pipe h by the blast passing its top, the sand from the
hopper g is drawn through the said pipe h into the blast pipe e and is carried
forward by the current of air to the globe k or other article to be operated upon in
the chamber f; l is the exit pipe for the blast in the chamber f provided with a
wire gauze diaphragm (see Figure 3). The exit blast pipe has on its underside
a vessel or receiver (see Figure 2) into which the fine sand carried with the blast
falla. This fine sand is removed from the receiver by taking off the cover 1. The
sand from the blast after it has operated upon the article falls onto the conical bottom
of the chamber f and from thence passes into the hopper g to be used over again.
The sand stored in the hopper is screened from dirt before it is again drawn into the
blast pipe. By means of the valve m the sand passing to the pipe h is regulated
or cut off. The pipe h³ immediately under the hopper into which the sand falls is
divided by a central division as seen at h³ in Figure 2. The globe or shade k (or
other article) on which the sand blast is to operate is supported at one side by the
spring support p and at the opposite side by the other support p carried by the
rod p having a hand wheel for working it the said rod p³ working through a
packed slot f³ in the chamber ƒ (see Figure 2). These supports are situated in the
top and bottom openings in the globe or shade k. The two supports p, p³ are
carried by the angular frame q, q crossing the chamber f as a diameter. On the
underside and middle of the frame q is a spindle q³ capable of rotating in the fixed
tube q carried by the bottom of the chamber f. By supporting the globe k in the
manner represented all parts of it can be brought under the action of the sand
blast. The chamber f is furnished with a hinged cover f' by opening which the
articles can be arranged in and removed from the said chamber.
8
By means of the supplementary sand blast pipe r, 7 and branched holder & the
insides of the shades or articles may be operated upon by the sand blast and by
means of taps or stopcocks the sand blast may be put in communication with or
cut off from the delivery pipes e³ or r³.
Figure 8 represents in elevation and Figure 9 in vertical section the apparatus
which we use for operating upon flat sheets or articles. In this arrangement the

page_text: sand blast delivery pipe t² is situated centrally in the chamber f and the flat sheet
or article u to be operated upon is placed over the opening in the support v. By
moving the sheet or flat article over the hole in the support all parts of its surface
can be operated upon in succession by the sand blast. In the said Figures 8 and 9,
t is the blast pipe and the pipe through which the sand from the hopper y is
drawn into the blast as herein before described. The air escapes from the chamber
f by the pipe fo the bottom of which nearly touches the water in the cistern ƒ 6 and
the fine sand carried with the air is collected in the said cistern. The sand from
the blast after it has operated upon the article falls into the hopper y by the
inclined bottom f'.
In order to increase the efficiency of the condensed air it may be heated and its
elastic force increased. To effect this the reservoir after the air has been con-
densed in it may be heated either by the direct application of a source of heat to
the reservoir or by the introduction of steam into a steam jacket surrounding the
reservoir.
Having now particularly described and ascertained the nature of our invention
and the manner in which the same is to be performed we declare that we claim as
our invention of "Improvements in the sand blast process and in apparatus
employed in the said process
First Conducting the said sand blast process by the use of condensed or
compressed air in place of a current of air produced by a fan or jet of steam as
ordinarily employed substantially as hereinbefore described and illustrated in the
accompanying Drawings.
Secondly The general arrangement or combination of the parts of apparatus for
compressing or condensing the air and storing the compressed air and for drawing
the sand into the current of condensed air substantially as herein before described
and illustrated in the accompanying Drawings.