Year: 1895

page_text: Date claimed' for Patent under Sect: 103 of Act;)
12
being date of first Foreign Application (in 22nd June, 1894
Sweden),
•
T
Date of Application. (in: United Kingdom), 21st Jan; 1895
Complete Specification Left, 21st Jan., 1895-Accepted, 6th July, 1895
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I CARL GUSTAF PATRIK DE LAVAL of 16 A. Handtverkaregatan, Stockholm,
Sweden, Doctor of Philosophy and Engineer do hereby declare the nature of this
invention and in what manner the same is to be perforined, to be particularly
described 'and ascertained in and by the following'statement:
For the purpose of regulating the supply of power to steam motors, à piston.
movable in a cylinder is applied,' said piston in all positions being kept in
equilibrium by the following pressures viz. on one side by the available, steam
pressure and on the other side by the pressure of a fluid passing through the
cylinder together with the pressure of a spring. The piston.is connected with the,
steam admission mechanism while the motor governor mechanism is combined with
a throttling device which determines the pressure action of the said fluid upon the
piston. The steam pressure thus balances the spring pressure and the liquid
pressure. As however during work the governor mechanism' produces rather large
variations in this 'liquid pressure the difference between the steam pressure on one
side of the piston and the liquid pressure on the other side of the piston may
become rather considerable, the consequence being a leakage of steam from the
steam space to the liquid space. This leakage might be partly obviated by the
use of a very deep piston but, such an one would work hard and it is of importance
for obtaining a quick and certain regulation"
'that the piston should work with great
ease. This invention has for object to avoid this inconvenience and consists in
arranging the piston as a double piston, upon whose intermediate part the liquid is
let in, which by a specially constructed appar
apparatus is kept at a pressure which at
any moment is either as high as the steam pressure or somewhat lower or higher
than
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steam can leak
to the liquid
the steam pressure for in that case only an insignificant
through from the steam space to the liquid space which is
leaking into the steam space." This liquid will thus by an adjustable 'leak-
arrangement leak through to the other end of the double piston, and in the conduit
therefrom the throttle valve which is influenced by the motor governor 101:
is inserted
for carrying out the regulation.
221.
In the accompanying drawing are shown as examples three somewhat differing...
arrangements constructed according to my invention.
11
Yfi
A Fig. 1'is the cylinder and B' the piston. The steam enters at C and passes to
the motor through D. "The steam admission is here effected' by a valve E in one
with the piston and having its seat in the cylinder. The steam pressure at one end
of the piston has to balance against the spring S and the pressure of t
the liquid
flowing through the upper part of the cylinder and which enters the upper part

page_text: at F and passes out at G. In the conduit screwed on at G is inserted the throttling
device which is actuated by the governor of the motor for varying the water
pressure on the upper end of the piston and regulating thereby the steam admission.
In order that the piston B should work easily as aforesaid it is provided with an
annularly reduced part H into which liquid is let. This liquid may suitably
consist of the feed water to the boiler. If the pressure of the feedwater as is the
case with boilers with long spiral tubes be considerably higher than the steam
pressure the water pressure is lowered by a special apparatus so that it becomes
nearly that of the steam pressure. This water leaks through from the space H to
the upper part of the piston by a small passage L formed in the wall of the
cylinder A and made adjustable by a screw peg M. The water pressure in the
space H is not influenced by the variations in pressure caused by the governor in
the space above the piston.
The modification in Fig. 2 consists chiefly in that the sectional area of the leak
passage is automatically rendered variable according to the pressure variations on
the upper end of the piston so that this area is throttled or diminished when the
pressure diminishes and opened or enlarged when the pressure increases. The
upper part of the piston B is for this purpose bored out to receive a plunger L³.
This latter again is provided with a small passage L' which establishes communica-
tion between the space H and the space H' above the piston B by means of the
passage F in the piston.
The plunger L is at its upper end acted on by the spring S'. It is thus clear
that the plunger changes position all according as the pressure in the space H¹
varies while the pressure in the space H is nearly constant, so that it moves
upward narrowing the passages Fi and F2 when the pressure diminishes and
downwards opening the said passages, when the pressure increases.
Instead of having the plunger L2 in a bored out part of the piston B, it may as
shewn in Fig. 3 be arranged in a separate cylinder outside of the regulating
apparatus proper A, the upper and lower ends of said cylinder being connected
with the spaces H and H' respectively. In the same way the passage L with the
screw peg M may be arranged in a piece separate from the cylinder A. The
recess H may also as shewn in Fig. 3 be in the cylinder A.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that
what I claim is :
1. In regulating arrangements for steam motors where the regulation is effected
by means of a piston which is movable in a cylinder and connected to the appliance
for steam admission and which on one side is acted on by the steam pressure and
on the other by the pressure of a spring and that of a liquid in constant flow, in
the conduit for which is inserted a throttling device combined with the governor,
the application of a recess or space arranged either round the piston or in the
cylinder somewhere between the two ends of the piston, which space communicates
with the liquid space at the one end of the piston by means of a small passage
provided with one or more adjustable throttling devices for the purpose of by
admission of liquid into said recess under approximately the same pressure as that
of the steam to prevent or in a desired degree to limit the leakage between the
steam space and liquid space in the cylinder, substantially as set forth.
2. In regulating arrangements of the character named in the first claim the
arranging of the small passage in the wall of the cylinder and the regulation of
same by means of a screw peg M entering said passage, substantially as set
forth.
3. The modification of the arrangement secondly claimed in that the small
passage is applied in a piston which is movable in a cylinder and under the
influence of a spring and communicates through passages entering said cylinder
with the spaces named in Claim 1, for the purpose of obtaining an automatic
regulation of the sectional area of the small passage, substantially as set forth.

page_text: 4. The special construction of the small passage in the piston named in Claim 3,
viz. that it is contained in a bored out part of the regulating piston B itself
substantially as set forth.
Dated this 21st day of January 1895.
JENSEN & SON,
77 Chancery Lane, London, W.C., Patent Agents.