IMPROVEMENTS IN THE CONSTRUCTION AND REGULATION OF BOILERS FOR HEATING BUILDINGS
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Ambrose Marriott at the Office
of the Commissioners of Patents, with his Petition, on the 4th July
1870.
I, AMBROSE MARRIOTT, of Higham Ferrers, in the County of North-
ampton, Agricultural Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE CONSTRUCTION AND REGULATION OF BOILERS
FOR HEATING BUILDINGS," to be as follows:-
I make an enlargement in the flow pipe close to the boiler, and within
this enlargement I place a cylindrical tube, the inner tube is screwed into
the top of the enlarged chamber, and is made air-tight by means of a
screw plug at the bottom; it is connected to the enlarged chamber by
flanges and bolts, which are faced to each other so as to fit truly; the bore
of the internal tube may be varied according to circumstances, but half-
inch bore is preferred. The under face of the flange of the internal tube is
bored out to about three times the size of the bore of the internal tube
and about one-eighth inch deep, a disc of india-rubber well vulcanised and
of sufficient diameter to cover the recess in the lower flange and for
forming a proper joint is then bolted between the flange of the internal
tube and another flange piece having a central aperture of half-inch

page_text: diameter and with projecting lugs or side pieces for carrying the levers
attached to the valve rod.
The valve for regulating the admission of air to the ash-pit is suspended
by a spindle passing through its centre and resting in bearings on each
side of the valve box; the valve is weighted on its upper edge sufficiently
to counteract the weight of the valve rod and its appurtenances and to
keep the button on the top of the rod in close contact with the india-
rubber disc. The rod is attached to the valve at a point near to the
centre, so that a slight upward or downward motion of the rod will open
and close the valve in a greatly increased proportion. To the upper end
of the rod is attached a compound lever with its fulcrums bearing on the
lugs cast on the flange placed below the india-rubber disc for the purpose
of increasing or multiplying the motion given by the india-rubber disc
to a sufficient degree for all practical purposes, and at the point of contact
with the india-rubber disc the rod is fitted with a button of hard wood
or other material fitting loosely in the central aperture of the lower
flange.
The action of the regulator is as follows:-The internal tube is filled
with mercury, care being taken to exclude all air and moisture, and the
valve is adjusted by means of a screw swivel, so that it is full open when
the water in the boiler is cold; on the fire being lighted, and as the water
becomes heated the mercury contained in the internal tube expands, and
acting on the india-rubber disc forces it downwards to a degree corre-
sponding to the degree of heat imparted to the water, and by means of the
rod in contact with it closes the valve.
In this manner by a little practice the heat of the water may be
maintained at an uniform temperature, the opening given by the valve
being regulated by means of the screw swivel, so that the amount of air
admitted to the ash-pit is exactly proportioned to the degree of heat
desired.
Another part of the improvements consist in providing the boiler with