Improvements in Apparatus or Alarms for Indicating the Level of Water or Liquids under Pressure in Boilers or other Vessels.
Year: 1895

page_text: Date of Application, 9th Jan., 1895
Complete Specification Left, 8th Oct., 1895-Accepted, 9th Nov., 1895
PROVISIONAL SPECIFICATION.
Improvements in Apparatus or Alarms for Indicating the Level of
Water or Liquids under Pressure in Boilers or other Vessels.
We THOMAS FLEWETT CRADDOCK of 7 East India Avenue in the City of
London Engineer and DAVID DONALD of Penryn in the County of Cornwall
Engineer do hereby declare the nature of this invention to be as follows:-
I
This invention has for one of its objects to provide, in connection with apparatus
for indicating the level of water, or liquids, under pressure, in boilers, or other
vessels, wherein a hollow float is used, means whereby any water, or liquid, which,
may enter the said hollow float can be readily expelled without difficulty, or
disconnection of the apparatus. The invention also has for its object to provide,
in connection with gauges for indicating the level of water, or liquid, under pressure
in boilers, or other vessels, means whereby a signal is given when a predetermined
level, (either a high level, or a low level, or both,) of water, or liquid, is attained.
In order to allow of the removal, as aforesaid, of water, or liquid, which may gaiu
access to the interior of the float, the float is made with a connection leading to
outside the vessel in.which it works, the said connection forming a means by which
the interior of the float can be put into communication with the outer air. This
connection may be the indicating stem attached to the float, as shewn, for instance,"
in Figures, 1, 2 and 3 of the drawings attached to the Specification of Letters
Patent No. 21654 dated the 26th November 1892, granted to one of 'us, (David!"
Donald), and James Robinson,-the said stem being made hollow and opening, at
its lower end, into the interior of the float, and at, or 'towards, its other end" being
provided with a screw plug, or other means, by which it can be closed. When the
gauge glass is removed, this cap, or the like, can be removed from the said hollow
stem, and then, owing to the heat in the boiler, or vessel, the liquid contents of the
float will be expelled, and the cap, or the like, and the gauge glass can then be
replaced. Or the said connection can be constituted by making the hinged arm B
shewn in Figure 4 of the aforesaid 'drawings hollow, and in communication at one
end with the float, and at the other end, by a passage in the hinge or pivot, and
bearing on which it turns, with the outer air, or with three-way, cock, which can
be turned so as to put the interior of the float into communication either with the
outer air, or with the boiler, or vessel, so that when in the latter position water, or
liquid, will enter the float, and, by turning the cock in the reverse direction, the
heat in the boiler, or vessel, will cause the water, or liquid, 'to be driven from the
With
float and the interior of the float, will thus be thoroughly purged.
apparatus as thus arranged, or with apparatus arranged as described in the"
aforesaid Specification, we may combine a high, or low, water level indicator, or
alarm, or both a high and low water level indicator, or alarm, consisting of a valve
controlling a passage through which steam, or water, or liquid, under pressure can
escape when the said valve is opened by the movement of the Hoat to the.
predetermined lowermost, or uppermost, position, or both. This can be effected by
means of the arm, or connections, on, or connected with, the stem of the float. For
example, when the float is provided with an arm turning on a centre as aforesaid,"
the arm may pass through a slotted hole in a piece attached to the valve, so that,
when the arm descends to the position of low water level, the arm will act on the
said piece and open the valve. A similar arrangement may be used for the.
་
.J
L

page_text: indication of high water level, and for this purpose the arm may be extended to the
other side of the centre on which it turns if the bigh and low water levels are both
to be signalled.
The apparatus may be in a casing attached to the boiler, or vessel, so that the
float is in the boiler, or vessel, itself; or the whole, including the float, may be in
a vessel attached to the boiler, or main vessel, so as to be in communication
therewith.
It will be understood that the invention can be applied to high or low water level
alarms or indicators or alarms or indicators for both high and low water levels
either with or without the indicator for intermediate levels..
Dated this 9th day of January 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
Improvements in Apparatus or Alarms for Indicating the Level of
Water or Liquids under Pressure in Boilers or other Vessels.
We THOMAS FLEWETT CRADDOCK of 7 East India Avenue in the City of
London, Engineer, and DAVID DONALD of Penryn in the County of Cornwall,
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 has for one of its objects to provide in connection with apparatus
for indicating the level of water, or liquids, under pressure in boilers, or other
vessels wherein a hollow float is used, means whereby any water; or liquid which
may enter the said hollow Hoat can be readily expelled without difficulty, or
disconnection of the apparatus. The invention also has for its object to provide,
in connection with gauges for indicating the level of water, or liquid, under pressure
in boilers, or other vessels, means whereby a signal is given when a predetermined
level (either a high level, or a low level, or both) of water, or liquid, is attained.
In order to allow of the removal, as aforesaid of water or liquid which may gain
access to the interior of the float, the 'Hoat is made with a connection leading to
outside the vessel in which it works, the said connection forming a means by which
the interior of the float can be put into communication with the outer air.. This
connection may be the indicating stem attached to the float, as shewn for instance.
in Figures 1, 2 and 3 of the drawings attached to the Specification of Letters
Patent No. 21654 dated the 26th November 1892 granted to one of us (David
Donald) and James Robinson, the said stem being made hollow and opening, at its
lower end, into the interior of the float, and at or towards its other end being
provided with a screw plug, or other means, by which it can be closed.. When the
gauge glass is removed this cap, or the like can be removed from the said hollow
stem, and then owing to the heat in the boiler, or' vessel the liquid 'contents of the "
float will be expelled and the cap, or the like, and the gauge glass can then be
replaced. Or the said connection can be constituted by making the hinged arm B³
shewn in Figure 4 of the aforesaid drawings hollow, and in communication at one
end with the float, and at the other end by a passage in the hinge, or pivot, and
bearing on which it turns with the outer air, or with a three-way cock, which can
be turned so as to put the interior of the float into communication either with the
outer air, or with the boiler, or vessel, so that when in the latter position water or
liquid will enter the float, and by turning the cock in the reverse direction, the heat
in the boiler, or vessel, will cause the water, or liquid, to be driven from the float
and the interior of the float will thus be thoroughly purged. With apparatus as
thus arranged, or with apparatus arranged as described in the aforesaid Specification,

page_text: we may combine a high, or low, water level indicator, or alarm, or both a high
and low water level indicator, or alarm, consisting of a valve controlling a passage
through which steam, or water, or liquid, under pressure can escape when the said
valve is opened by the movement of the float to the predetermined lowermost, or
uppermost position, or both. This can be effected by means of the arm or
connections on or connected with the stem of the float. For example, when the
float is provided with an arm turning on a centre as aforesaid, the arm may pass
through a slotted hole in a piece attached to the valve so that when the arm
descends to the position of low water level, the arm will act on the said piece and
open the valve. A similar arrangement may be used for the indication of high
water level and for this purpose the arm may be extended to the other side of the
centre on which it turns if the high and low water levels are both to be signalled.
The apparatus may be in a casing attached to the boiler, or vessel so that the
float is in the boiler, or vessel, itself; or the whole including the float may be in
a vessel attached to the boiler, or main vessel, so as to be in communication
therewith.
We will describe with reference to the accompanying drawings an arrangement
according to this invention from which the manner in which it may be carried out
in practice will be readily understood but we do not limit ourselves to the precise
details of the example shewn in the drawings.
Figure 1 represents in vertical section a gauge and high and low water alarm
constructed according to this invention in which the float and lever are arranged
inside the boiler and the indicating and alarm arrangements are outside the
boiler.
Figure II is a section on the line 1-2 Figure 1.
Figure III is a section on the line 3-4 Figure 1.
Figure 1V shews separately one of the valves for actuating the alarm or
signalling whistles.
The same reference letters apply to all the figures.
A is a metallic vessel connected to the boiler, part of which boiler is shewn at X,
and B is a projection on the said vessel A carried through to inside the boiler and
having in it openings to give communication between the interior of the boiler
and the interior of the vessel A. The centre line of this projection B is preferably
a little above the highest determined water level indicated at C. D is a hollow
shaft working easily in suitable bearings 62 and a in the said projection B and
vessel A. E is a hollow lever firmly connected at its upper end to one end of the
hollow shalt D by the union piece d and carrying at its lower end the hollow
float F so that the interiors of the float Flever E and shaft D are in communication
with each other and with the cock S. G is the cover of the vessel A in which the
outer end of the shaft D works in the steam tight bearing a. H is a double armied
lever securely fixed to the hollow shaft D by the wings d² thereof. is a
prolongation of one end of the aforesaid lever H the end of the said prolongation
being fattened as shewn. 12 are valve rods the upper ends of which carry
valves which govern the admission of steam to the whistles or signalling
apparatus KK the said valve rods sliding in guiding lugs a² and being provided
with stops against one or other of which the respective ends of the lever H
will strike if it be moved far enough in either direction. M is the needle or rod,
the valve Z at the end of which rests on the end of the lever H. This needle or
rod is for indicating the levels of water or liquid in the boiler or vessel as
described in the Specification of the aforesaid Letters Patent No. 21654 of 1892.
N is a gauge glass (or tube of other transparent material) into which the indicating
needle or rod M projects the said needle or rod passing through a suitable guide Y.
The metallic holder L holds the gauge glass and is securely fixed to the metallic
vessel A by the guide Y. P is a spring which holds the valves on the rods I' I²
against their seats to close the passages to the whistles or signalling apparatus K K².
Qis a spring which presses against the bearing washer 2 which presses against the
flange d on the hollow shaft D to keep its outer end steam tightly against the

page_text: bearing a in the cover G of the metallic vessel A. 'S is a three-way cock fixed
into the cover G. The branch 1 of this cock communicates with the interior of
the hollow shaft D. The branch 2 communicates by means of the pipe T with the
boiler, at a point below the lowest predetermined water level and the branch 3
leads to the atmosphere.
If the branches 1 and 2 be put in communication by the three-way cock the
interior of the float F will be opened to the pressure from the boiler and the
float will receive water from the boiler and' the said float will sink and if desired
may be sunk far enough for one end of the lever H to come against the stop 2 on
the valve rod 12 and by depressing it open the valve at its top and allow steam to
pass to the low-water alarm whistle K2 and by sounding it shew that this part of
the apparatus is in working order. At the same time the end of the lever H will
be depressed and the needle or rod M following it will indicate that that part of
the apparatus also is in working order.
If the branches 1 and 3 are now placed in communication by means of the
three-way cock the water will be expelled from the interior of the float F by reason
of the heat in the boiler expelling it through the branch 3 to the atmosphere. The
float F will then rise, the alarm whistle K2 will cease to sound as the valve rod I2
will be released and the spring P will cause its valve to bear against its seat and
the indicating needle or rod M will risc in the glass N to a position correspondingly
to that of the float F.
If the three-way cock be left so that the passages 1 and 3 communicate with each
other the interior of the float F will be open to the atmosphere and any slight
leakage which might find its way into the interior of the Hoat (and which in the
ordinary course would accumulate therein and cause it to sink) will be evaporated
and the float will be kept thoroughly purged, whilst as the water level in the
boiler rises and falls between the predetermined high and low water levels the
needle or rod M will indicate such rise and fall. If the rise or fall reaches either
the predetermined high or low water level one or other of the alarm whistles will be
sounded.
The arrangement of three way cock and connections above described is for
testing purposes and may, or may not, be fitted to the apparatus. In the latter
case in an arrangement such as that shewn the interior of the float will always be
open to the atmosphere.
The parts in connection with the gauge glass N and needle or rod M may be
arranged and connected as described in the Specification of the aforesaid Letters
Patent No. 21654 of 1892 or in any other suitable way.
The holder L is shewn as being so secured that it can be readily removed with
the glass N 10 facilitate the insertion of a glass or for any other purpose the valve Z
preventing the escape of the steam or liquid through the perforations m of the needle
or rod M by closing against the opening U.
Although we have referred to boilers and water and steam it will be readily
understood that the high and low level indicating or alarm apparatus may be used
with vessels generally containing fluid under pressure and that the means for
expelling water or liquid from the float may be used with vessels generally containing
fluid under pressure and subjected to sufficient heat.
The apparatus may be in a casing attached to the boiler or vessel and the float
be in the boiler or vessel or the whole including the float may be in a vessel
attached to the boiler or inain vessel so as to be in communication therewith.
It will be understood that the invention can be applied to high or low water level
alarms or indicators or alarms or indicators for both high and low water levels either
with or without the indicator for intermediate levels.
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. In apparatus or alarms for indicating the level of water or liquids under

page_text: pressure in boilers or other vessels a float with a communication from its interior to
outside the boiler or which can be opened to outside the boiler substantially as and
for the purposes hereinbefore described.
2. In apparatus or alarms for indicating the level of water or liquids under
pressure in boilers or other vessels a float with a communication from its interior to
outside the boiler and to the interior of the boiler and a three-way cock by which
communication can be opened between the interior of the float and the interior of
the boiler or outside the boiler substantially as and for the purposes hereinbefore
described.
3. An apparatus or alarm for indicating the level of water or liquids under
pressure in boilers or other vessels the combination with a float in the boiler or in
a vessel communicating with the boiler of a valve controlled communication to an
alarm and a device in connection with or operated by the float to open the said
valve when a predetermined high or low level of water or liquid is reached
substantially as herein before described.
4. An apparatus or alarm for indicating the level of water or liquids under
pressure in boilers or other vessels the combination with a float in the boiler or in
a vessel communicating with the boiler of valve controlled communications to
alarms and a device in connection with or operated by the float to open one of the
valves when a predetermined high level of water or liquid is reached and to open
the other of the valves when a predetermined low level of water or liquid is reached
substantially as herein before described.
Dated this 8th day of October 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.