US119522A - Improvement in alarm apparatus for steam-boilers - Google Patents

Description

im l JOSEPH KIRK.

Improvement in Alarm Aparatusfor Steamv Boilers.

n l 8 All 3 e .el

UNITED STATES PATENT QEEICE.

JOSEPH KIRK, OF LONDON, ENGLAND, ASSIGNOR TO GEORGE JORDAN FIRMN.

IMPROVEMENT IN ALARM APPARATUS FOR STEAM-BOILERS.

Specification forming part of Letters Patent No. 119,522, dated October 3, 1871.

To all whom it may concer-u:

Be it known that I, J osEPH KIRK, of No. 1l Blossom street, in the city of London, England,

'a subject of the Queen of Great Britain, have and in what manner the same is to be performed to be particularly described and ascertained in and by the following,` statement thereof-that is to say:

This invention has for its object improvements in alarm apparatus for giving warning when the pressure in a steam-boiler or vessel workin g under pressure is too high or the water-level too low. The apparatus consists of a vessel containing a liquid, such as mercury, which will expand by heat without sensible evaporation. The vessel is closed at the top by a valve, and on the mercury is a iioat, which, at a -certain temperature to which the apparatus is adjusted, presses against the under side of the valve. The vessel containing the mercury is inclosed in a jacket, to which the steam or water from the boiler is admitted. At the top of the jacket is also a valveseat and a valve. The two valves are connected by a stem, and as they are of the same area they pressures upon them balance each other. The valves are thus very easily lifted by the iloat.

' v/Vhen the valves are closed the pressure in the mercury-chamber on the under side of the valve does not exceed the pressure above the upper valve. This is insured by forming a small passage through the stem connecting the two valves. A whistle is fixed on the top of the jacket over the upper valve, and when steam passes this whistle sounds. As soon as the valve is slightly `lift`ed by the float the steam rushes into the merapparatus constructed according to my invention.

a a is a vessel of iron. It is partly filled with mercury, and there is a loat, b, on the surface of the mercury. The iioat maybe iron or other material on which the mercury will not act; it

should, however, be heavier than water. The vessel a is closed at the top by a valve, c, and the quantity of mercury is so adjusted that the float unseats the valve when the mercury is sufat the ltemperature of steam of the pressure at which the instrument is to act. For a low-water alarm the adjustment is made to a temperature a little over 2120, rather higher for a high-pressure boiler than for a low pressure. d is a jacket surrounding the mercury-vessel, and this case is `in connection with the boiler by a pipe on which is a stop-cock. For a pressure-alarm a connection 1s made with the upper part of the boiler, so that the jacket is always filled with steam; and for a low-water alarm the connection is made with the lower part of the boiler, so that the jacket only fills with steam when the water `in the boiler is low. The pipe connecting the instrument with the boiler should be sufficiently long to insure that the temperature of the water in the jacket shall be considerably under the boiler-temperature. When steam enters the casing the boiler-temperature is at once communicated to the apparatus. The jacket d is closed .at the top by the valve c1, which is soldered or cept when the float acts upon them; but immediately they are started by the float the steam enters the mercury-chamber a, more rapidly than it can escape by the perforation c3, and the pressure which thus accumulates in this chamber' forces up the valves until the passage is fully open for the steam to pass to the whistle.

Having` thus described the nature of my said invention and the manner of performingthe same7 I would have it understood that I claiml. The combination of the equilibriumyalves with a mercurydioat or equivalent instrument for starting them from their seats7 and a chamber in

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