IMPROVEMENTS IN THE DRAW OFF TAPS OF KITCHEN BOILERS AND OF SUCH LIKE HOT WATER APPARATUS
Year: 1881

page_text: LETTERS PATENT to John Davidson, of Auchmill, Aberdeen, Scotland, for an
Invention of." IMPROVEMENTS IN THE DRAW OFF TAPS OF KITCHEN BOILERS
AND OF SUCH LIKE HOT WATER APPARATUS."
PROVISIONAL SPECIFICATION left by the said John Davidson at the
Office of the Commissioners of Patents on the 9th February 1881.
JOHN DAVIDSON, of Auchmill, Aberdeen, Scotland. "IMPROVEMENTS IN THE
DRAW OFF TAPS OF KITCHEN BOILERS AND OF SUCH LIKE HOT WATER
APPARATUS."
This Invention has for its object to prevent the bursting of kitchen boilers and
other such like hot water apparatus. It has before been proposed to provide
kitchen boilers with ordinary safety valves, but to do this is worse than useless,
as in course of time the safety valves through corrosion become set and cease to
act.
According to this Invention I provide a kitchen boiler with a draw off tap, which
is so formed as also to serve the purpose of a safety valve. The constant using of
this tap for drawing off hot water from the boiler keeps the working parts of the
tap from becoming set, and so maintains it in good working order and free to act as
a safety valve.
This may be effected by employing a tap constructed in the following manner:—
The shell of the tap I form with an enlarged chamber having a partition across it to
divide the inlet of the tap from its outlet. Through the centre of this partition,
which is horizontal, a hole is formed and fitted with a valve, the stem of which is
passed out through a hole in the shell of the tap. A weighted lever is caused to
bear upon the stem so as to hold the valve down to its seat. When water is to be
drawn off from the boiler the tap is opened by raising this lever and so lifting the
valve, or in place of a lever a spring might be used to act upon the stem of the valvo
and hold the valve down to its seat. In this case when water is to be drawn off
from the boiler the tap would be opened by relieving the spring from pressure
and so allowing the valve to open. The stem of the valve where it passes out
through the shell of the tap is made to pass through a hole in a plug, which is
screwed into a large hole in the shell. This construction permits of the valve seat
being readily ground or faced, and also permits of the valve being taken out from
the tap if repair is necessary.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Davidson in the Great Seal Patent Office on the 5th August
1881.
JOHN DAVIDSON, of Auchmill, Aberdeen, Scotland.
WATER
"IMPROVEMENTS IN THE
DRAW OFF TAPS OF KITCHEN BOILERS AND OF SUCH LIKE HOT
APPARATUS."
This Invention has for its object to prevent the bursting of kitchen boilers and
other such like hot water apparatus. It has before been proposed to provide kitchen
boilers with ordinary safety valves, but to do this is worse than useless, as in course
of time the safety valves through corrosion become set and cease to act, and the
pipes in connection get choked up.
According to this Invention I provide a kitchen boiler with a draw off tap, which
is so formed as also to serve the purpose of a safety valve. The constant using of
this tap for drawing off hot water from the boiler keeps the working parts of the
tap from becoming set, and so maintains it in good working order and free to act as
a safety valve.
This may be effected by employing a tap constructed in the following manner :—
The shell of the tap I form with an enlarged chamber having a partition across it
to divide the inlet of the tap from its outlet. Through the centre of this partition,
which is horizontal, a hole is formed and fitted with a valve, the stem of which is
passed out through a hole in the shell of the tap. A weighted lever is caused to
bear upon the stem so as to hold the valve down to its seat. When water is to be
drawn off from the boiler the tap is opened by raising this lever and so lifting the
valve, or in place of a lever a spring might be used to act upon the stem of the
valve and hold the valve down to its seat. In this case when water is to be drawn
off from the boiler the tap would be opened by relieving the spring from pressure
and so allowing the valve to open. The stem of the valve where it passes out
through the shell of the tap is made to pass through a hole in a plug, which is
screwed into a large hole in the shell. This construction permits of the valve seat
being readily ground or faced, and also permits of the valve being taken out from
the tap if repair is necessary.
In order that my said Invention may be most fully understood and readily
carried into effect, I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation, and Figure 2 is a transverse section of a draw off
tap for a kitchen boiler. It is suitable also for use with any hot water apparatus
in which undue pressure may result from the pipes becoming blocked.
a, a, is the shell of the cock, and a' is a diaphragm between the inlet and the
outlet side; b is a valve adapted to a hole and seating formed in and upon the
diaphragm a¹; c is a cover screwed into the shell. The stem of the valve b passes
through the cover c, and the valve is held to its seat by a weighted lever & bearing
upon the top of the valve stem. The lever d has its fulcrum at d' on a pin passing
through lugs formed upon the cap c.
This draw off tap should be placed near the boiler, usually or often it will be
couvenient to have it over the kitchen, sink, where hot water is most often drawn
for use.
The constant employment of the draw off valve for this purpose renders it
impossible that the valve should set fast or become unserviceable without the defect
being immediately observed.
In case of stoppage in the hot water pipes this valve will open and relieve the
pressure before danger arises.

page_text: What I claim is the construction of draw off taps of kitchen boilers or like hot
water apparatus, substantially as herein described, so that they will open
automatically, thereby ensuring safety in case of obstruction occurring in the
pipes.
In witness whereof, I, the said John Davidson, have hereunto set my hand
and seal, this Twenty sixth day of July, in the year of our Lord One thousand
eight hundred and eighty one.
JOHN DAVIDSON. (L.S.)