Improved Means for Governing Engines, applicable also to Protecting them from Water Returning Up the Exhaust Pipe.
Year: 1899

page_text: Improved Means for Governing Engines, applicable also to Protecting
them from Water Returning Up the Exhaust Pipe.
We, PERCY ARCHIBALD Low and WILLANS & ROBINSON, LIMITED, both of
Victoria Works, Rugby, Engineers, do hereby declare the nature of this inven-
tion to be as follows:-
In order to prevent racing when there is a sudden great reduction of load,
either by reason of slowness of action on the part of the ordinary governor, or
by reason of the quantity of steam already in the engine at the time when
the throttle valve is closed, or the cut-off made earlier by the governor, we fit a
throttle valve in the exhaust from the engine and operate it by the piston of an
auxiliary steam cylinder the inner end of which is always in communication
with the exhaust on the engine side of the exhaust throttle valve and the outer
end is put by a governor according to the speed of the engine either into com-
munication with the exhaust on the other side of the exhaust throttle valve or
with the atmosphere or some other source of pressure such as the steam chest or
the receiver of a compound engine.
When the engine is running normally the exhaust throttle valve is fully open
and the piston is at the outer end of the auxiliary cylinder the pressure on its
two sides being equal. A tendency is given to the piston to remain in and
return to this position by a weight or spring or by reason of its two sides having
different areas. If however the speed of the engine increases the governor puts
the outer end of the cylinder into communication with the atmosphere or other
source of pressure and the piston is moved inwards closing the throttle valve
more or less. The result is an increase of back pressure in the engine, and as
soon as this approximately equals the atmospheric or other pressure the auxiliary
piston would again move outwards and open the exhaust throttle valve, unless
prevented from doing so.
In order that this automatic relief from excessive back pressure shall not occur
too early, a catch is provided and so arranged that it gives way easily to allow
the exhaust throttle valve to close, but will only allow it to return to the open
position by overcoming the resistance of a weight or spring, regulated to yield
when any desired back pressure is reached.
The controlling valve may be actuated alternatively by the movement of a
float in the exhaust pipe, arranged to lift in the event of water coming back from
the condenser. The exhaust valve will then close in the same manner as though
the engine were running at excessive speed, and with the same safeguard against
the back pressure becoming excessive.
It is obvious that the arrangement described may be used merely as a protec-

page_text: tion for the engine against water from the condenser, and without reference to
speed regulation.
Improved Means for Governing Engines, applicable also to Protecting
them from Water Returning Up the Exhaust Pipe.
We, PERCY ARCHIBALD Low and WILLANS & ROBINSON, LIMITED, both of
Victoria Works, Rugby, Engineers, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement:-
In order to prevent racing when there is a sudden great reduction of load,
either by reason of slowness of action on the part of the ordinary governor, or
by reason of the quantity of steam already in the engine at the time when
the throttle valve is closed, or the cut-off made earlier by the governor, we fit a
throttle valve in the exhaust from the engine and operate it by the piston of an
auxiliary cylinder the inner end of which is always in communication
with the exhaust on the engine side of the exhaust throttle valve and the outer
end is put by a governor according to the speed of the engine either into com-
munication with the exhaust on the other side of the exhaust throttle valve or
with the atmosphere or some other source of pressure such as the steam chest or
the receiver of a compound engine.
When the engine is running normally the exhaust throttle valve is fully open
and the piston is at the outer end of the auxiliary cylinder the pressure on its
two sides being equal. A tendency is given to the piston to remain in and
return to this position by a weight or spring or by reason of its two sides having
different areas. If however the speed of the engine increases the governor puts
the outer end of the cylinder into communication with the atmosphere or other
source of pressure and the piston is moved inwards closing the throttle valve
more or less. The result is an increase of back pressure in the engine, and as
soon as this approximately equals the atmospheric or other pressure the auxiliarv
piston would again move outwards and open the exhaust throttle valve, unless
prevented from doing so.
In order that this automatic relief from excessive back pressure shall not occur
too early, a catch is provided and so arranged that it gives way easily to allow
the exhaust throttle valve to close, but will only allow it to return to the open
position by overcoming the resistance of a weight or spring, regulated to yield
when any desired back pressure is reached.
The controlling valve may be actuated alternatively by the movement of a
float in the exhaust pipe, arranged to lift in the event of water coming back from
the condenser. The exhaust valve will then close in the same manner as though
the engine were running at excessive speed, and with the same safeguard against
the back pressure becoming excessive.
It is obvious that the arrangement described may be used merely as a protec-

page_text: tion for the engine against water from the condenser, and without reference to
speed regulation.
Figure 1 is an elevation partly in section of an apparatus constructed
according to this invention. Figure 2 shows a modification.
a is the exhaust pipe, its left hand end a¹ being connected to the engine. bis
a throttle valve in the exhaust pipe its movement in one direction being limited
by a stop a The valve is connected by a rod b¹ to a piston in the
cylinder c. is the spindle of the valve b. In Figure 1 the cylinder e is open
to the exhaust pipe on the engine side of the valve whilst in Figure 2 its end
is closed and it is connected to the exhaust pipe (also on the engine side of
valve) by the pipe, the piston having differential areas.
In this case the rod being outside the exhaust pipe is connected to an arm
fixed to the spindle 2 which passes through the pipe.
In Figure 1 the valve carries a weight 63, but in the arrangement shown in
Figure 2 this is not necessary, the pressure of the atmosphere exceeding that
of the exhaust.
d is a pipe connecting the outer end of the cylinder e to the exhaust pipe on
the side of the valve away from the engine. e is a valve on the pipe d and
operated from the governor of the rod e¹. e² is a passage in the shell of the
valve open to the atmosphere.
The spindle has the arm & fixed to its end outside the exhaust pipe a. f is
a lever pivotted at fl and carrying a weight f2. g is a catch pivotted at g¹ to
the lever f. The right hand or tail end of the catch y bears against the lever f
so that the catch cannot turn from right to left but it is free to turn from left
to right as shown in dotted lines. As the valve b closes the arm & comes into a
horizontal position as shown lifting the catch which then drops back again into
the position shown in full lines so that the valve can only open again by turning
the lever f and lifting the weight f2.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. A valve in the exhaust pipe moved in one direction by the pressure in the
pipe (on the engine side of the valve) and in the other direction by the governor.
2. A valve in the exhaust pipe operated by a piston in a cylinder one end of
which is always in communication with the pipe on the engine side of the
valve whilst the other end is put by a governor either into communication with
the pipe on the other side of the valve or with a source of pressure.
3. The combination with the subject matter of the preceding claims of means
whereby the re-opening of the valve is impeded.
4. The substitution in the preceding claims of a float in the exhaust pipe for
the governor.
5. Means for governing engines applicable also to protecting them from
water returning up the exhaust pipe substantially as described and illustrated
in the drawings.
PERCY A. LOW.
WILLANS & ROBINSON, LIMITED
GILBERT ALLYTON EAST }
MARK ROBINSON
C. S. Essex.
Secretary.
Directors.