Appliance for Removing Scale or other Foreign Substance from the Interior of Boiler Tubes.
Year: 1896

page_text: Date of Application, 22nd Sept., 1896-Accepted, 31st Oct., 1896
COMPLETE SPECIFICATION.
Appliance for Removing Scale or other Foreign Substance from the
Interior of Boiler Tubes.
We, WILBER DAVID FORSYTH, Tool-maker, residing at 121 Kelley Street
(Station D) in the City of Pittsburg, Allegheny County, and State of Penn-
sylvania, in the United States of America, and ENOS THOMAS BELL, Machinist,
residing at the corner of Brushton and Frankstown Avenues (Station D) also in
the City of Pittsburg, in the said county and state, do hereby declare the
nature of our invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The object of this invention is to provide means for clearing the scale from the
interior of the water tubes of steam boilers or other tubes needing similar cleaning,
and which is designed to be more effective in its operation than any other device
for the purpose, in that it will remove a greater thickness of scale, will work
with greater rapidity, and is capable of being more readily repaired and kept in
order.
With these objects in view, the invention consists in the novel construction and
combination of parts, all substantially as hereinafter described and illustrated in the
accompanying drawings in which
Figure 1 is a view in section and side elevation, showing the invention as in
operation;
Figure 2 is a plan view illustrating the manner in which the cleaner and its
appliances may be attached to a boiler for operation thereon;
Figure 3 is a view, partly in section, showing the cleaner head its shaft and
guide;
Figure 4 is a section on the line - Figure 3;
Figures 5 and 6 are side and front views respectively, of one of the cutters
carrying disks and its cutters;
Figure 7 is a section on the line y-y, Figure 6;
Figure 8 is a sectional view showing the manner in which the driving pulley N
is mounted on the cleaner shaft.
Figure 9 is a detail view of a modification of the cone F; and Figures 10 and 11
are side and front views, respectively, of disks provided with a different arrangement
of cutters.
Referring to these drawings, the letter A designates a shaft which is designed
to be rotated at a high rate of speed, and which forms the carrier for the cleaner.
Said cleaner consists of a plurality of rolling cutters or serrated wheels B,
preferably arranged in graduated series, whereby the foremost ones cut to as small
a diameter as may be necessary, each succeeding series cutting to a larger diameter
as they follow.
While there are various ways of attaching these cutters to the shaft A, the
arrangement which is shown in the drawing, and which will now be described is
that which we consider to be the best and most practical. A series of disks or
sections C are provided, the rearmost one of which is usually rigidly attached
to the shaft A by means of a collar a, while the succeeding ones are keyed to the
shaft so that they rotate therewith, but are nevertheless capable of being removed
from the shaft by an end wise movement. In the drawing I have shown six of
these disks or sections, but any suitable number may be employed.
Pivotally secured to the forward face of each of these disks are a series of
arnis D (three being shown in each series, although we do not confine ourselves to

page_text: such number). The pivotal points of these arms are eccentric, and their free end
portions are arranged to project a short distance beyond the peripheries of the
disks, the movement of said arms being limited by means of check pins c on their
posterior faces which play each in a slot d of the disk. Each of said arms is
slotted at its outer portion, and journaled in the slot of each arm is one of the
rolling cutters B, which consists of a small peripherally toothed or serrated
wheel.
The cutters on the first or front disk of the series are arranged to work in a
circle of comparatively small diameter, each succeeding series increasing the
diameter of its action. This is accomplished either by making the disks C of
gradually increasing diameters, and by making corresponding changes in the length
of the arms D, as indicated in the drawings or by varying the amount of outward
play which the successive series of arms shall have, this being, as before stated,
controlled by the check pins.
The arms D of the different series are preferably not attached to the respective
disks at corresponding points, but the points of attachment are so disposed that the
cutters are brought into spiral relation to the axis of the shaft in order to
distribute the points of bearing more evenly, whereby the device runs much more
steadily.
The journals for the cutters, and for the arms D usually consists of pins headed
at one end, said pins being removable and held against accidental removal by the
forward faces of the disk bearing against them. In front of the forward section
is a cone F, which forms a guide for the device. By the removal of this cone, the
disks with their cutters may be successively removed from the shaft, and when so
removed any one of the arms D or of the cutters may be quickly removed and
replaced if damaged or broken.
Figures 10 and 11 show a modified form of one of the sections, wherein the
cutters B are journaled directly on the face of the disk with their teeth projecting
beyond the periphery, the journals consisting of removable screws k. Pins are
provided to keep the disks at the proper distance from each other. The
graduation in this form is effected by making the disks C of different diameters.
The cone F may consist of a smooth-surfaced piece, as seen in Figure 3,
which acts not only as a guide, but also as a guard to prevent damage to the
cutters in case of running into an obstruction. It also holds the forward cutters
up when passing over an unusual thickness of scale in the bottom or lower sides
of the tube. A nut secures said cone.
When, however, the tubes to be cleaned are badly filled up, this cone will be
provided with a series of cutters B (see Figures 1 and 9) which work in slots g cut
in the surface of the cone. These cutters are usually arranged in spiral form. It
will be readily seen that when so equipped it will cut its way through a very small
opening. The cutters are preferably somewhat heavier than those of the preceeding
sections. This form of cone is arranged to be screwed onto the forward portion
of the shaft the latter passing only partially through it, whereby it does not
interfere with the cutters at the smaller end.
H designates a rear guide for the device. This guide as shown comprises two
spiders through which the shaft A loosely passes, the arins h of such spiders being
connected by longitudinal bars ', the whole forming a cylindrical frame which
is neatly fitted to the interior of the tube into which it is to be inserted. "In
operation, it centers the device, preventing the weight of the cutting part from
resting too heavily upon the bottom of the tube. It also acts as a regulator for
the feed, since if any scale is left behind the cutters, the guide will strike it and
stop further progress until such a scale is removed, which necessitates drawing
back the cutters to that point. The shaft A is usually further centered inside the
tube by means of spider bearings H' secured against movement upon the shaft by
means of collars' and set screws. The arms of the spiders have fastened
thereto bars H2 which lie longitudinally in the tube and guard against oscillation
and vibration of the shaft.

page_text: The operation of the device is as follows:
The cutting part is inserted into one end of the tube and is pushed therethrough
by means of the shaft A. Said shaft during its passage through the tube is
rotated at a high rate of speed, usually about 1500 revolutions per minute. Under
this rotation the rolling cutters expand, each series to their full extent, being held
in yielding yet sufficiently rigid contact with the work. In this manner the cutters
adapt themselves to the unevenness usually found in tubes, and each series cuts its
own thickness. The check pins in addition to limiting the outward throw of the
arms D, also limit their inward movement and prevents the cutters from striking
the heels of the adjacent arms.
During the operation, a stream of water should be kept flowing through the tube
operated upon, of sufficient volume to wash away the scale as it is cut loose: other-
wise such scale forms a cushion between the cutters and the lower wall of the tube
and destroys to a certain extent the effectiveness of the tool. The water also
prevents the tool from heating on account of its rapid rotation.
A small stream is
sufficient for both purposes.
To facilitate the entrance of the device to the tube, a short piece of pipe or
tube I of the same diameter as the tube to be operated upon, is usually provided,
and is clamped to the tube proper. The cutting part and so much of the guide H
as it will receive, is then thrust into such short pipe or tube, and the power
applied. As the cutting part revolves the device is pushed gradually into the
tube proper.
Inasmuch as it is necessary to be able to remove the shaft A to bring its
axis into alignment with the axis of any tube of a boiler, and to move said
sbaft endwise during its rotation, special bearings and driving mechanism must be
provided.
The arrangement shown in the drawings for this purpose and devised therefor
is found to be an efficient and practical one and the same will now be
described.
L, L, designates the plates which during operation are designed to be securely
belted to the cover holes of the header of the boiler being cleaned. These
plates carry heavy, forwardly projecting tubes or rods L', L', which support a
transverse bar M.
M' is a clamp arranged to slide upon said bar and to be secured thereto by
means of set-screws m. L is a post adjustably held in a socket of said clamp, and
having at its upper portion a socket part L' through which the shaft A. is designed
to loosely pass.
This socket part has secured therein a sleeve or thimble n of a stirrup N in
which is journaled a driving pulley N¹ for said shaft. The latter is arranged to
pass loosely through the arms of this stirrup, and is formed with a longitudinal
groove or key-way p, which receives a spline or feather p₁ of said pulley.
Attached to said stirrup is an arm or bar P which at its opposite end portion
carries a twin pulley P¹ one part of which is belted to the pulley N', and the other
part to a power shaft.
By sliding the clamp M' along the bar M, and raising and lowering the
post L³, and occasionally moving the plates L, L, the entire boiler front can
be traversed bringing the shaft A and the pulley Ni in alignment with the axis
of any tube.
The arrangement also permits the shaft to be moved end wise through the driving
pulley and at the same time maintain its driving connection therewith.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is-
1. The means for removing foreign substance from the interior of boiler tubes,
all substantially as berein shown and described.
2. The herein described means for removing foreign substances from the interior

page_text: of boiler tubes, consisting essentially of a rotary head or carrier adapted to be
forced through the tube to be cleaned under rapid rotation, and having loose
toothed or serrated cutter wheels or disks attached thereto, a shaft which carries
the head guides for said head, and means for rotating the said head, all
arranged, constructed and combined in substantially the manner shown and
described.
Dated this 22nd day of September. 1896.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.