Blow-off for Steam Boilers.
Year: 1895

page_text: Date of Application, 21st May, 1895-4ccepted, 13th July, 1895
Blow-off for Steam Boilers.
We, HERMANN WALTER LESLIE, Engineer, ROBERT ALEXANDER CARSON,
General Broker, and THE O. F. ZURN COMPANY, a corporation existing under and
by virtue of the laws of the State of New Jersey, all of 418 Vine Street, in the
City of Philadelphia, State of Pennsylvania, 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 object of our invention is to prevent sedimentary deposits and incrustation
in steam boilers. For this purpose we place a pipe horizontally within the boiler
near its bottom and running its whole length. Said pipe is of the peculiar
construction illustrated in the accompanying drawing, to which we beg to refer.
A is a steam boiler, near the bottom of which is fixed a pipe consisting of two
concentric lengths or sections, B. and C. We shall refer in the following to Bas
the first section, and to C as the second section. Said pipe extends outside and
beyond said boiler at its rear, and terminates in the valve chest F. The first
section B is of smaller diameter than the second section C, and it runs the whole
length from the valve chest aforesaid, partly inside and partly outside the second
section C, to the front end of the boiler; while the second section C runs from said
valve chest to about midway within said boiler, the two sections being concentric.
The surface of said pipe, which is exposed within the boiler, is pierced with a
number of apertures, D and E, at regular intervals along the length of both sections.
These apertures may be of any desired shape; that is, rouud, oval, oblong, etc., and
The ends of each
they may be lined with any non-corrosive metal to prevent rust.
section within the boiler are closed. In the valve chest is placed a quick acting
valve of any ordinary pattern easily opened and shut, while a connecting pipe
carries away to the sewer.
In operation, when the valve is opened, as the area of the exhaust capabilities of
the pipe is greater than the sum of all the apertures in the same, the sudden
discharge of the water and steam creates a temporary vacuum and causes a suction,
inducing a powerful agitation in close proximity to the bottom of the boiler, which
detaches any scale formed thereupon and breaking it up into small particles carries
it and all other sedimentary matters in solution through the apertures in said pipe
and away to the sewer. By the peculiar construction of our blow-off the two
concentric sections operate in different portions of the boiler; the first section in the
forward portion and the second section in the rear portion; with the result of
securing, instantly the valve is opened, a complete and full equalization of suction
over the entire length of the boiler. It is well understood that the common blow-
off affects only that portion of the boiler within a limited area of the opening,
unless the boiler be nearly emptied, which is at the expense of time and fuel.
The frequently used perforated pipe lying at the bottom of the boiler is little better
than the common blow-off, by reason of the openings nearest the valve being
affected first, and the expansion of the steam having a tendency to back up and
prevent a free inflow uniformly throughout its length. It will be observed there
are no apertures in that portion of the first section of our blow-off pipe which lies
within the second section. This feature makes each section separate and distinct,
and by this form of construction the objections named above are overcome, as the
opening of the valve causes both pipes to discharge at the same time, operating
independently of each other, and as only a few gallons of water in combination

page_text: with the sediment and steam are blown out at each opening, the apparatus may be
operated several times during the day, (according to the quantity of water
evaporated) thus keeping the sediment constantly agitated and preventing it from
baking and adhering to the plates and tubes. A regular and systematic use of this
blow-off will carry off all bediment before it has any chance to scale. We have
shown but two sections; it is evident that more may be used under certain
conditions with advantage.
We do not lay any claim to the broad feature of a perforated pipe placed within
a steam boiler and connected with a valve and other apparatus for cleaning said
boiler by a blow-off, for such devices are old and have been known heretofore.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the said is to be performed, we declare that what we
claim is :
The combination with a steam boiler of a blow-off, consisting of two or more
concentric pipes of different lengths and diameters each separately connected with
a quick acting valve common to all, the pipes of smaller diameter extending beyond
those of greater diameter, as in a telescope, the exposed surface of the whole length
of piping within said boiler being perforated by regularly placed apertures,
substantially as described and shown.
Dated this 21st day of May 1895.
BOULT & WADE,
Agents for the Applicants.