IMPROVEMENTS IN STEAM-ENGINE GOVERNORS
Year: 1880

page_text: LETTERS PATENT to Nathan Edward Nash, of Westerley, in the County of
Washington, in the State of Rhode Island, one of the United States of
America, for the Invention of "IMPROVEMENTS IN STEAM-ENGINE GOVERNORS."
COMPLETE SPECIFICATION filed by the said Nathan Edward Nash at the
Office of the Commissioners of Patents on the 26th February 1880.
NATHAN EDWARD NASH, of Westerley, in the County of Washington, in the
State of Rhode Island, one of the United States of America. "IMPROVEMENTS IN
STEAM-ENGINE GOVERNORS."
This Invention relates to certain improvements in that class of governors in
which atmospheric air compressed within a cylinder by means of an air pump
driven from the engine is used to elevate a weighted piston, and close the governor-
valve to which it is indirectly connected, the opening of the said governor-valve
being caused by the depression of the weighted piston as the tension of the coni-
pressed air acting underneath thereof is reduced by the diminished speed of the
engine through the medium of the air-pump aforesaid.
In the further description of my Invention which follows, due reference must be
had to the accompanying Drawing forming a part of this Specification, and in
which,―
Figure 1 is a vertical section of my improved governor with an air-pump
attached; and Fig. 2, a sectional plan of the same.
Similar letters of reference indicate similar parts of the Invention in both
Figures.
A is an air-pump of ordinary construction secured to the frame or other
stationary portion of the engine, and operated from the steam-valve stem or other
moving part of the same; B is a cylinder connected to the air-pump A in such
manner as to receive the air discharged from the same at a point below the
piston C. The piston-rod C¹ extends from the piston C through a suitable packing-
box in the upper end of the cylinder B, and is attached directly or indirectly to the
governor-valve D, the operation of which regulates the flow of steam to the steam-
cylinder of the engine.
The opening of the governor valve by its movement in a downward direction is
obtained by means of a weight E attached to the piston rod C¹, or to some

page_text: connection thereof having a corresponding movement derived therefrom. The
upward movement of the governor-valve, by which movement it is closed, is
caused by the pressure of the compressed air from the air-pump, the air acting upon
the under side of the piston C and finding its escape through the aperture a, the
size of which is regulated by a valve or stop cock b. F is a supplemental, or
regulating cylinder having a piston F' and a rod extending therefrom to an arm
projecting from the piston rod C to which it is fastened. The piston in the
cylinder F is in two parts c and d, one of which is susceptible of being turned
circumferentially independently of the other. This circumferential movement of
one part of the piston is for the purpose of opening or closing perforations e in the
said piston, and thereby establishing or closing the connection between the portions
of the cylinder above and below the piston.
Upon the engine being placed in motion air is forced by means of the air-pump
A to the cylinder B, and acts directly upon the under side of the piston C elevating
the weight E, and closing the governor-valve. The pressure of air in the cylinder B
regulates the vertical position of the piston C, and the quantity of steam admitted
to the steam cylinder by means of the governor-valve. Consequently it is only
necessary to control this pressure to obtain any desired speed of the engine. To
acquire this control over the air pressure I provide the discharge-aperture a with
the valve b before alluded to, which is accessible to the engineer, and is graduated
to indicate the areas of opening necessary to give different numbers of revolution of
the engine. The supplemental cylinder F before alluded to is filled with oil, water,
or other liquid and is for the purpose of preventing an objectionable sensitiveness
of the piston C and its connections, the said liquid offering a resistance to displace-
ment or change of position through the medium of the piston F' in proportion to
the area of communicating openings in the same.
Having thus described and ascertained the nature of my said Invention, what I
claim is substantially as follows,—
1. As a pneumatic engine-governor, an air-pump and communicating air cylinder
combined with a supplemental cylinder, the piston of which has a movement
common with that of the air-cylinder piston, and operates in a fluid for.preventing
the too sensitive action of the governor-valve.
2. In a steam-governor, the cylinder B, piston C, and piston-rod C', in com-
bination with the supplemental or regulating cylinder F, the said cylinder F being
provided with a piston having perforations therein, the effective sizes of which are
variable, the said piston being operated through the medium of suitable mechanism
from the piston rod C³.
In testimony whereof, I have hereunto set my hand and affixed my seal, this
Twenty fifth day of June, in the year of our Lord One thousand eight
NATHAN EDWARD NASH. (L.S.)