IMPROVEMENTS IN INDICATING THE SPEED OF ROTATING SHAFTS OR BODIES, AND APPARATUS THEREFOB
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by Henry Stracey Barron at the
Office of the Commissioners of Patents, with his Petition, on the
23rd April 1874.
I, HENRY STRACEY BARRON, of Langdale Road, Greenwich, in the
County of Kent, Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN INDICATING THE SPEED OF ROTATING SHAFTS
OR BODIES, AND APPARATUS THEREFOB," to be as follows :-
My Invention is designed to enable the speed at which a shaft or
body is at any time rotating to be readily ascertained by merely looking
at a suitable gauge or indicator without its being necessary for that
purpose to refer to a watch or other timekeeper.
.
It is well known that a centrifugal pump immersed in liquid in a
vessel having suitable suction and delivery passages or orifices will,
when caused to rotate therein, balance a column of such liquid, tho
height of which column so supported will depend upon the velocity at
which the pump is driven.
Now my Invention has reference to utilizing this property of the
centrifugal pump for indicating the speed of rotating shafts or bodies,
and relates to the application and use, in connection with a rotating
shaft or body whose speed is to be indicated, of a centrifugal pump

page_text: adapted to receive motion from such shaft or body, and to operate upon
a body of liquid in connexion with a gauge or indicator in such manner
as by changing the height of the column of liquid supported by the
pump as the speed at which it is driven from the rotating shaft or body
varies to cause the necessary indications to be produced by or upon the
gauge or indicator.
In one form of the apparatus I employ a centrifugal pump arranged
to be rotated within the lower end of a circular vessel into which the
liquid is to be discharged. The suction pipe is arranged concentrically
within the circular vessel, an annular space being left between the two
of greater area than the suction pipe. The reservoir of liquid for sup-
plying the pump is contained in an elongation of the suction pipe. By
this arrangement a fall of the liquid in the suction pipe is accompanied
by a lesser rise in the annular space, thus enabling the air in the upper
part of the suction pipe to be attenuated by the action of the pump :
at a moderate speed. The suction pipe is made air-tight, and its upper
part is connected to a barometer which may be of either the aneroid or
liquid column class; thus the variations in the height of the column of
liquid balanced by the pump will cause the gauge to be operated so as to
indicate upon its dial the number of rotations within a given period of
time of the shaft or body whence the pump.derives motion. Motion
from the rotating shaft or body may be communicated to the pump
through a strap and gearing.
In another form of the apparatus I employ an open-ended suction
pipe, and use a float either upon the surface of the liquid contained
therein or upon the surface of the liquid in the annular space between
the suction pipe and outer vessel.
In another modification of the apparatus the necessary indications
are obtained by the action upon a pressure gauge of air compressed by
the pump.
As is obvious the form of the apparatus may be otherwise modified
to suit circumstances without departing from the distinctive character
of my Invention.