Year: 1888

page_text: Date of Application, 13th Sept., 188
Specification Accepted, 26th Oct., 1888
simultaneously Signalling the same.
1, THOMAS NORTHEY, of 131 Shuter Street, Toronto, Ontario, Canada, 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:
This invention relates to a novel construction or arrangement of apparatus, in which
a bent tube closed at top and open at bottom is fitted to a boiler and having its lower
end slightly immersed in the water when at its proper level but which when the water
goes below a fixed level allows steam to enter the tube and by its increased tempera-
ture to cause the tube to bend to a greater distance, the tube being otherwise fixed at
top and bottom, so that the tube can come in contact with a valve spindle and force
the valve from its seat permitting steam to pass through the valve by a pipe to a
whistle fitted thereon.
The apparatus is automatic in its action and while the water is maintained at its
proper level, the bent pipe remains in its normal condition but when the water gets
low and clears the bottoin of the lower tube, the additional heat of the steam bends it.
to a greater extent and causes the valve to open and when the boiler is recharged to
its proper level the steam within the bent tube instantly condenses and the tube
returns to its normal condition by decrease of temperature and the valve closes under
the action of a spring and a pressure of steam on the back of the valve which has
free entry up the valve tube to the valve for that purpose.
The invention will be well understood by reference to the annexed drawings, in
which Figure 1 is a sectional elevation of the apparatus fitted to a boiler showing three
water levels, the upper one of which is the proper level, the middle line showing by
the water guage when the feed should be attended to, the lower line showing the
dangerous level.

page_text: Figure 2 is a part transverse section through the line a, b, Figure 1.
Figure 3 is an enlarged view through the line a, c, of Figure 1 and Figure 4 is a
detached sectional view of the valve and steam whistle.
According to Figure 1, A, A, is an open cast iron column or stand.
tube.
B the bent
Ca cap. Da small steam pipe carrying on its upper end the valve E
valve chamber F, and whistle G. M is the pipe leading down to the water in the
boiler. N is a small screw in cap C and stands A, A.
The valve box or casing has studs or projections H, H, to bear against stops I, I, of
the recesses J, J, formed within the upright or standard A, A.
Figure 3 which shows the parts of actual dimensions indicates the relative distance
between the bent tube B to the point of valve spindle E when cold.
K is the spring
on the back of the valve E to keep it to its seat, the valve spindle E is fitted within a
tapered or conical aperture as a guide.
The bent tube B is preferably of wrought iron and screwed into the base of the
stand A, A, steam tight and closed at the upper end by welding and turned to fit into
a cavity made in the cap C. The said cap is screwed down on the point of the bent
tube B and adjusted so as to barely touch the said tube, the cap C is then screwed to
the stand A, A, permanently by means of a small screw N passing through the cap C
and stand A, A. The bent tube B is about 30 inches in length and inches internal
diameter and bent over towards the valve spindle to about of an inch from same
when cold.
The small steam pipe D is screwed into the small steam passage D¹ formed in the
base of the stand A, A, to carry steam from the boiler to the back of the valve E to
keep it on its seat and also to supply the whistle with steam when the valve opens to
call the attendant to his duty. The steam pipe D is so made that when the valve
chamber is screwed on it, the projections H, H, will bear against the stops I, I,
these stops are cast in a piece with the stand A, A, as shown in Figure 3 to keep the
valve chamber F in position while in action.
The recesses J, J, are made long, as shown, to facilitate the fitting and also to
allow the valve to be pressed back against the tube B by hand for the purpose of
fully opening the valve to clear it of any grit that may lodge thereon, the recesses J, J,
are made about inch wide to allow for the expansion and contraction of pipe D)
and the more easy fitting of the same. The valve E is made concave in front as
shown in Figures 3 and 4 to allow the guide L to project into the cavity in front of
the valve E and out of the line or direction of the steam in its passage through the
valve E to the whistle, protecting both the guide and valve spindle from grit or any
foreign substance that may be carried over by the steam, thereby enabling the valve
to work free and clear of same.
It will further be seen in the drawing that the guide L is enlarged to scatter the
condensed steam that may collect in the valve chamber F causing it to be blown into
the instrument and be again converted into steam whereby the boiler would be kept
perfectly clear of any water dropping in and injuring it.
The action of this instrument is based on the expansion and contraction of the bent
tube caused by the varying temperature contained therein. Its mode of operation is
as follows:-
When the water in the boiler falls below the orifice of the pipe M, the water
contained in the bent tube B and pipe M instantly falls into the boiler and steam
taking its place being a good conductor of heat imparts at once a higher temperature
to the bent tube B and as the said tube cannot expand in line of its length (being held
at both ends) it expands over towards the valve E opening communication between
the boiler and whistle which sounds but as soon as the water in the boiler again covers
the orifice of the pipe M, the instrument no longer being supplied with hot steam
from the boiler, the steam contained in the bent tube B being condensed by radiation
causing the pipe M and the bent tube B to again be filled with water and being of a
lower temperature and a bad conductor of heat causes the tube B to contract and
draw away from the valve E allowing it to close and the sound to cease.

page_text: Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed I declare that what I claim is :-
1. The bent tube B attached to stand A, A, by the cap C and small screw N for the
purpose therein described.
2. The form of valve E and its guide L for the purposes therein set forth.
3. The projections H, H, on valve chamber F, the stops I, I, and the elongated
recesses J, J, for the purposes herein before described.
4. The combination of the several parts shown at Figure 1 as an automatic low
water indicator in boilers and as a means for calling attention thereto as set forth.
Dated this 13th day of September 1888.
H. GARDNER,
166, Fleet Street, London,
Agent for the said Thomas Northey.
H. GARDNER,
166, Fleet Street, London,
Agent for the said Thomas Northey.