Improvements in Valve Gear for Steam Engines.
Year: 1889

page_text: Date of Application, 3rd May, 1889-4ccepted, 15th June, 1889
COMPLETE SPECIFICATION.
Improvements in Valve Gear for Steam Engines.
I, FERDINAND BOSSHARDT, of the firm of F. Bosshardt & Co. of 4 Corporation Street,
Manchester in the County of Lancashire, Engineer and Patent Agent, do hereby
declare the nature of this invention which has been communicated to me from abroad
by Johann Rudolf Frikart, of 122 Rue Nationale Lille, France, Engineer, and in
what manner the same is to be performed to be particularly described and ascertained
in and by the following statement
-
All steam engines with rotary valve (Corlis) gear existing heretofore possess the
defects of not being able to exceed a certain comparatively low number of
revolutions, while the hereinafter described invention will permit of an equal favourable
distribution of steam at any desired large number of revolutions
And in order that my invention may be more fully understood I have caused to
be appended hereunto two sheets of drawings marked with letters of reference
indicating like parts in the various figures
Fig. 1 Sheet I is a cross section and Fig. 2 a longitudinal section of the valves
and cylinder.
Figs 1 & 2 Sheet II, are also longitudinal sections of the valves and cylinder.
In carrying out my invention, the distribution of steam is effected by means of
four rotary valves, two of which are shown in Figs. 1 & 2 Sheet I.
Each of these rotary valves is formed with four cavities, the opposite ones being
in connection with each other by means of the ports e, e and f.f formed through the
body of the valve.
These four cavities in the rotary valve correspond with an equal number of
openings formed in the wall of its casing, viz. A the steam inlet, B the channel
leading to the cylinder, while A¹, B¹ are cavities arranged symmetrically thereto.
Owing to this particular position an equal pressure is always maintained on both
sides of the rotary valve and thus perfectly balanced
The top or inlet valve, see Fig. 2 is shown in the position when it commences to
open which is effected simultaneously at four different points a, b, c, d.
Through the openings c & d which are nearest to the cylinder, a part of the
ngoing steam passes direct into the inlet port B, while the remainder, entering
at a & b, must pass each of the channels e formed in the rotary valve.
The great advantage thus attained from the particular position, is that after the
rotary valve has passed of the width of the channel, the whole section of the saine
has already been presented to the entering steam.
The arrangement described represents a single cylinder engine in which, as shown
in Figs. 1 & 2 Sheet I, the exhaust of the steam may also be effected by means of
the balanced rotary valve described, or the inlet of the steam only, while for the exhaust
ordinary unbalanced rotary valves may be used.
Fig. 1 Sheet II shows an engine with cylinders arranged tandem in which the
inlet valves A, A¹ as well as the outlet valves B, B' of the smaller or high pressure
cylinder are balanced, while the valves D, D¹, and E, E¹ of the large or low pressure
cylinder are of ordinary construction.
The outlet valves B. B₁ of the small one, and the inlet valves D, D¹ of the large
cylinder are connected through a pipe which can be heated.
The pistons of both cylinders are fixed on one rod, thus acting on the same
crank.
Fig. 2 Sheet II, shows an engine with two cylinders arranged side by side.
If not, particular circumstances, for instance in marine engines where easy
manipulation is required, necessitate having the two cranks at a right angle, the same
may be formed at 180°, which besides the good equilibrium of the valves, has yet the
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page_text: advantage that for two cylinders as shown in Fig. 2 only 6 rotary valves are required,
two of which, balanced, A, A' regulate the admission to the small cylinder, while B. B¹
serve as outlet valves for the small, as well as inlet valves for the large cylinder.
It is evident that through wholly, or partly combining the arrangements shown
in Figs. 1 & 2, 3 or 4 cylinder engines may be made giving equal advantageous
results, ie, one or both of the piston rods, Fig. 2 may be extended and respectively
over the one or the two cylinders, a 3rd or 4th cylinder arranged tandem like.
It is also evident that this modification is applicable for vertical horizontal, or
diagonal engines.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim 19
In steam engines with rotary valves
1st. The balanced 1otary valve, which owing to its peculiar form permits the inlet
of the steam simultaneously at four different points, and increases fourfold the motion
caused by its motion, substantially as described and with reference to Sheet I.
2nd The combination of the balanced and ordinary rotary valves for two or more
cylinder engines, substantially as described and with reference to Sheet 11.
Dated May 2nd AD 1889
F. BOSSHARDT & Co.,
4, Corporation Street, Manchester,
Agents to Applicant.