IMPROVEMENTS CONNECTED WITH SAFETY VALVES TO INDICATE AND RELIEVE EXCESS OF PRESSURE, AND TO INDICATE SCARCITY OR EXCESS OF WATER
Year: 1885

page_text: I ALEXANDER TURNBULL of Brook Street Glasgow Engineer do hereby declare
the nature of my invention for IMPROVEMENTS CONNECTED WITH SAFETY VALVES
TO INDICATE AND RELIEVE EXCESS OF PRESSURE, AND TO INDICATE SCARCITY OR
EXCESS OF WATER to be as follows:-
"
The object of my invention is to provide simple and efficient devices in connec-
tion with safety valves of steam generators or other fluid pressure vessels for
indicating when the maximum pressure is exceeded and when the water level
exceeds the maximum or falls below the minimum and opening the safety valve
and relieving the pressure when the water level becomes dangerously low.
This invention is particularly applicable in connection with safety valves of the
kind described in the Specifications of Letters Patent N° 4017 of 1876 and 3873
of 1877 but may also be used in conjunction with other forms of lifting safety.
valves.
According to one modification I form the weighted safety valve with a hollow
stem in the upper end of which a small valve is fitted and is loaded to a few
pounds in excess of the point at which the main valve rises and blows off steam.
Over this small auxilliary valve a steam whistle or similar alarm apparatus is fitted
and is acted on to sound an alarm when the pressure of steam within the generator
exceeds the normal pressure at which the main valve rises and attains the extra
pressure to which the small valve is loaded. The small valve may be loaded by a
weight fitted within the hollow stem of the main valve.
Within the boiler a beam lever is hung and is centred near the main safety
valve orifice and on each end of the beam lever is hung a float or weight―The
float attached to one end is immersed in the water below the normal water level
and that at the other end is attached at a point above which it is undesirable that
the water should reach. Vertically under the safety valve a vertical stem rod is
fitted and is jointed to the beam lever. When the water in the boiler falls to the
level of the low water float that float (whose weight is counterbalanced by that of
n •
073

page_text: the high water float or weight) falls with the water and tilts the beam lever which
raises the stem rod. The stem rod presses up the weight holding down the alarm
whistle valve and an alarm is sounded. If the water in the boiler is still allowed
to fall the float continues to fall and raises up the stem rod higher until a shoulder
formed on it comes in contact with the safety valve which it raises and allows the
steam to blow off freely.
If on the other hand the water level is abnormally raised the high water float is
lifted by the water and the beam lever is tilted in the same direction to raise the
stem rod and act first on the alarm valve and if need be on the safety valve.
In cases where an alarm whistle is not wanted the stem rod on the beam lever is
fitted to act directly on the safety valve.

page_text: Excess of Water.
I, ALEXANDER TURNBULL of Brook Street Glasgow, 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:-
The object of my invention is to provide simple and efficient devices in connec-
tion with safety valves of steam generators or other fluid pressure vessels for
indicating when the maximum pressure is exceeded and when the water level
exceeds the maximum or falls below the minimum and for opening the safety valve
and relieving the pressure when the water level becomes dangerously low. The
invention is particularly applicable in connection with safety valves of the kind
described in the Specifications of Letters Patent N° 4017 of 1876 and 3873 of 1877
but may also be used in conjunction with other forms of lifting safety valves.
In the accompanying drawings figure 1 is a section of part of a boiler showing in
sectional elevation one modification of my invention, and figure 2 is a sectional
elevation of a second modification.
As represented in the modification figure 1, I form the weighted safety valve A
with a hollow stem a in the upper end of which a small valve b is fitted and is
loaded to a few pounds in excess of the point at which the main valve A rises and
blows off steam. Over this small auxiliary valve b a steam whistle C or similar
alarm apparatus is fitted and is acted on to sound an alarm when the pressure of
steam within the generator G exceeds the normal pressure at which the main valve
rises and attains the extra pressure to which the small valve is loaded, the steam
from the boiler then escaping through the valve orifice at 6 and actuating the
alarm whistle. The small valve b may be loaded by a weight b¹ fitted within the
hollow stem a of the main valve A, or by a spring.
Within the boiler G a beam lever D is hung and is centred on a bracket g near
the orifices in the main valve casing E, and on each end of this beam lever D is
hung a float or weight F, F¹. The float F attached to one end is immersed in the
water below the normal water level and that F¹ at the other end is attached at a
point above which it is undesirable that the water should reach. Vertically under
the safety valve A, a vertical stem rod h is fitted and is jointed to the beam
lever D. When the water in the boiler falls to the level of the low water float F
that float (whose weight is counterbalanced by that of the high water float or
weight F¹) falls with the water and tilts the beam lever D which raises the stem
rod h. The stem rod h presses up the weight or spring holding down the alarm
whistle valve and an alarm is sounded. If the water in the boiler is still allowed
to fall, the float continues to fall and raises up the stem rod higher until a
shoulder h¹ formed on it comes in contact with the safety valve A, which it raises
and thereby allows the steam to blow off freely. If on the other hand the water
level in the boiler is abnormally raised the high water float F¹ is lifted by the water
and the beam lever D is tilted in the same direction to raise the stem rod hand

page_text: act first on the alarm valve b and if need be on the safety valve A. In cases where
an alarm whistle is not wanted the stem rod h on the beam lever D is fitted to act
directly on the safety valve, which being raised quite off its seat will allow the
steam to blow off so freely that the outflowing steam will in itself serve as an
alarm. A ball or other weight H suspended from the stem rod h seves to keep
said rod in the vertical position, the use of guides being thereby rendered
unnecessary. This ball may also be arranged to control or regulate the feed of
water to the boiler. As represented in figure 2 the lever D may be fitted to act
upon a stem rod h detached from it but arranged to operate a safety valve and
whistle or alarm as above described.
As a means of steadying the movement of the lever D under oscillations due to
pitching or rolling of the vessel wherein the boiler may be fitted, in cases in which
the apparatus is applied to marine boilers, I may provide an additional float F'
immersed in the water under the low water line and suspended from the lever D
as shown in figure 1, and in such cases a counterbalancing weight Fa may be hung
from the opposite end of the lever D as shewn in figure 2. When the apparatus is
used solely as a low water alarm the upper floats F1, F³ may be dispensed with
and the lower floats F, F, retained. In order that, in the event of the tubes or
other parts of the boiler being exposed owing to the heeling over of the vessel or
from other causes, the apparatus may more readily be brought into action while
the float F may still be immersed I, in some cases, fit at the end of the lever
carrying the high water float F¹ a shallow box I having its bottom sloped from the
sides towards the centre as represented at figure 2, carrying a ball which on
the canting of the boiler rolls to the end of the box adjacent to the centre of the
lever D and causes said lever to tilt and act on the safety valve or whistle.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is :-
1. The combination of parts constituting the improved safety valve apparatus
serving the several purposes of a high and low water alarm and of indicating and
relieving excessive pressure of steam in steam generators, substantially as herein
described with reference to the drawings annexed.
2. The combination with a safety valve of a whistle or alarm apparatus and a
stem rod or its equivalent connected to or operated by a lever to which movement
is given by floats acted on by the water within a boiler, substantially as herein
described with reference to the annexed drawings.
3. The arrangement in combination with a safety valve of the stem rod h and
balanced float lever D adapted to act thereon and on the valve, substantially as
and for the purpose set forth.
Dated this Twentyninth day of May 1886: