Improvements in Grid Iron Exhaust Valves for the Cylinders of Steam Engines and in Mechanism for Actuating such Valves.
Year: 1897

page_text: Improvements in Grid Iron Exhaust Valves for the Cylinders of
Steam Engines and in Mechanism for Actuating such Valves.
I, ALFRED HOYOIS, of Clabecq, in the Kingdom of Belgium, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement :-
My invention relates to grid iron exhaust valves for the cylinders of steam engines
and to the actuating mechanism of such valves and my said invention has for its
object to decrease the travel or stroke of the valves and the resistance due to friction
and also to considerably reduce injurious spaces and cooling surfaces.
In order that my said invention may be readily understood I will describe it with
reference to the accompanying drawings in which
Figure 1 is an elevation partly in section showing the lower part of a cylinder at
each end of which is placed horizontally a grid iron valve of my invention and the
actuating mechanism of the same.
Figure 2 is a plan of upperside of the two grid iron valves with their actuating
mechanism.
Figure 3 is a front elevation partly in section taken on the line A B Figure 1.
Figure 4 is a detail view showing the arrangement of the actuating rods of the two
grid iron valves illustrated in Figure 1.
.
In these figures the forward valve e and rear valve i are connected to their
respective actuating rods g k by pins or tenons n n passing through slots in the
middles of the valve seats or fixed parts in which the ports are formed and engaging
in recesses formed in the valves.
The rods g and k slide in parallel directions in supports p p below the cylinder
and their pins or tenons n, n are bent in opposite directions as shown in Figure 4.
The said rods are respectively jointed to the two arms d and h of an oscillating or
rocking lever c keyed on an axis b to which rocking motion is communicated by a
lever a actuated by the rod of an eccentric keyed on the driving shaft or connected
to the link motion if the engine has a reversing gear.
The arms of the lever c form between them such an angle that the movement of
the valves is almost arrested when once they are open or closed.

page_text: Figure 5 is a side elevation partly in section on the line C D of Figure 7.
Figure 6 is a front elevation partly in section on the line E F Figure 7 and
Figure 7 is a plan partly in section on the line G H Figure 6 illustrating
an arrangement in which the valves are placed in the ends of the cylinder.
Figure 8 illustrates in section drawn to an enlarged scale portions of the valve
and valve seat illustrated in Figures 5, 6 and 7.
In these figures the valve is actuated by a rod m passing into the exhaust
passage and carrying at its extremity a pin n which engages with a recess in the
valve. A to and fro motion is imparted to the rod m by an eccentric on the driving
shaft or by any suitable arrangement of levers.
The valves have by preference grooves formed in their bearing faces for allowing
of escape of steam at the commencement of the opening movement past the forward
and rear edges of all the ports as indicated by the arrows in Figures 1 and 8.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that I claim :—
FirstGrid iron exhaust valves for the cylinders of steam engines with or without
grooves in the rubbing surfaces of their bars arranged at the cylinder ends and
actuated by rods passing through the exhaust passage and furnished with a tenon or
pin which passes through and works in a slot in the valve seat and is engaged in a
recess in the valve substantially as hereinbefore described and illustrated in
Figures 5, 6 and 7 of the accompanying drawings.
Secondly-Actuating mechanism applicable to grid iron exhaust valves of the
kind referred to in the foregoing claim when placed at both ends of the bottom of
the cylinder, characterized by an oscillating or rocking lever having two arms to each
of which is connected the actuating rod of one of the valves the said two arms
forming together such an angle that the valves are nearly at rest when once they
are open or closed the two rods sliding in parallel directions in their supports and
being furnished with pins or tenons bent in opposite directions so that their heads
may respectively enter the centres of the valves which they actuate substantially as
herein before described and illustrated in Figures 1, 2, 3 and 4 of the accompanying
drawings.
Doted this Seventh day of December 1897.