CERTAIN IMPROVEMENTS IN HYDRAULIC ENGINES
Year: 1848

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANCIS
HASTINGS GREENSTREET, of Liverpool, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Second day of
December, One thousand eight hundred and forty-eight, in the twelfth
forty-eight, in the twelfth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Francis Hastings Greenstreet, my exors, adiñiors, and assigns, Her
especial licence, full power, sole privilege and authority, that I, the said Francis
Hastings Greenstreet, my exors, adñiors, and assigns, or such others as I, the
said Francis Hastings Greenstreet, my exors, adññiors, or assigns, should at
any time agree with, and no others, from time to time and at all times during
the term of years therein expressed, should and lawfully might make, use,
exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, my Invention of "CERTAIN IMPROVEMENTS IN HYDRAULIC ENGINES;" in
which said Letters Patent is contained a proviso that I, the said Francis
Hastings Greenstreet, should cause a particular description of the nature of my
said Invention, and in what manner the same is to be performed, by an instru-
ment in writing under my hand and seal, to be inrolled in Her said Majesty's
High Court of Chancery within six calendar months next and immediately

page_text: after the date of the said in part recited; Letters Patent, as in and by the
same, reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Francis Hastings Greenstreet, do hereby declare that the nature of my said
Invention, and the manner in which the same is to be performed, are fully
described and ascertained in and by the following statement thereof, reference
being had to the Drawings hereunto annexed, and to the figures and letters
marked thereon, that is to say:-
Figure 1 represents a horizontal section of the engine, with the valve
gearing, &c. removed, being principally intended to show the arrangement of
the valves.
Figure II. a plan of the engine.
Figure III. an end elevation. (The same letters refer to the same parts in
the several views.)
Referring to Figure I. (C) represents a horizontal cylinder, and P the
piston moving therein; R, the piston rod passing through a stuffing box;
X, the pipe or box containing the valves; V, V, V, Vd, are four valves,
V and V communicating with the head of water, and Ve and Va, the exhaust
valves opening to the atmosphere. The valves are circular and of the form
shewn in Figure IV., having the alternate segments open as at Z, Z, Z, Z.
These work upon faces similarly perforated; thus when the open segment in the
valve is brought over the open segment in the face, the valve is open, but
when opposite the metal in the face, the valve is closed (the ordinary
regulator of a locomotive engine and the damper used in many of the common
stoves is upon the same principle, and may serve to illustrate their action).
The four valves are all fixed upon a common spindle S, passing through a
stuffing box, which spindle has a reciprocal motion imparted to it by the action
of the weight W, Figures II. and III., falling alternately in opposite directions
(as will be hereafter explained); this motion of the valve spindle imparts the
same motion to all the valves at once, and is just sufficient to open and shut
them at the required time, and the valves are so adjusted on the spindle that
as two of the valves open the alternate two shut. The dotted circle B shows
the pipe by which the water is conducted to the machine. E, E, are the
exhaust pipes through which the water escapes after having exerted its
pressure on the piston, and Q, Q, the pipes communicating from the valves to
the cylinder. The valve Va, communicating with the head of water, is shewn
, and also the exhaust valve Vd, opening to the atmosphere; the other two
valves, V and Ve, are shut. The action of the engine is as follows:-A cock
or valve in the pipe B. (not shewn in the Drawing) being opened, admits the
open,

page_text: water from the head or reservoir into the valve pipe (X), and from thence it
passes through the open valve VA in the direction shewn by the arrows, and
presses upon the piston, forcing it the length of the cylinder, and any water
previously occupying the cylinder on the opposite side of the piston passes away
through the valve Vd.
When the pistou arrives at the end of its stroke, the
valves are reversed by the gearing (as will be explained), thus shutting the
valves VA and V₁, and opening the valves Vb and Ve; the water which had
just acted upon the piston passes away through Ve, and the pressure of the
column of water is brought to bear on the opposite side of the piston through
the valve Vb, and so on, an alternate reciprocating motion is kept up, similar
to the action of the common steam engine.
It now remains to explain the gearing by the medium of which the required
shifting of the valves is effected. This will be understood by reference to
Figures II. and III. F is a diagonal slide, to which a motion parallel to the
piston rod is imparted by a rod D connected to the slide and to the piston
rod, and consequently it has the same length of stroke as the piston; this
diagonal slide is kept in a parallel and proper position by means of two parallel
guide rods H, HI, which pass through slides L, L; keyed to the valve
spindle S is a collar G, with a slot T in its circumference. M is a lever, with
a weight W at its extremity; this lever works inside the diagonal slide, and
turns freely upon the valve spindle S without moving it, until a pin A projecting
from the back of the lever M, and moving in the slot T, comes in contact
with the collar G; Y is a guide in which the lever M works (not shewn in
Figure III.) The mode of action is as follows:-Upon the piston being put in
motion by the pressure of the column of water, a similar motion is imparted
through the piston rod R and the rod D to the diagonal slide F, which
sliding under the lever M resting upon it gradually lifts the lever and the
weight W, until near the end of the stroke it is brought into a perpendicular
position and thrown over the centre, when the weight W falls over in tho
opposite direction, carrying with it the lever M, until checked by the guard
Y, thus shifting the valves by the pin A coming in contact with the corner >
of the collar G at the instant when the weight begins to fall over; the
valves being shifted, the piston and slide are moved back again, and the weight
is lifted over by the opposite side of the diagonal slide until it again shifts the
valves. The object of this description of valve gearing is to prevent the engine
from coming to a rest near the end of the stroke, when only imparting a
reciprocating motion, and working without a, fly wheel, which would be liable
to happen were it not for the assistance of the weight W moving the valves
instantaneously at the required time, as otherwise the hydrostatic pressure

page_text: would be equivalent on both sides of the piston as soon as the valves were
partially shifted, and the piston would come to a rest, without it had acquired
sufficient velocity to carry it to the end of its stroke, and fully to shift the
valves.
Having now described the engine, I will point out what I consider to be
the advantages it possesses and the parts I claim as my Invention, which is in
the arrangement and combination of the valves. The valves are so constructed
that they are wholly unaffected by the pressure of the column of water, and
work as easily under an enormous pressure, for it will be perceived that in the
position the valves are shewn in the Drawing, the pressure acts upon the back
of the valve V and also upon V, and these being connected by the spindle S,
the pressure upon one counteracts the pressure upon the other, and thereby
prevents any tendency to force the valves against their faces, and likewise
when the valves are shifted the pressure upon V" counteracts the pressure
upon V. The concussion arising from the motion of the column of water
being suddenly arrested is entirely prevented by my arrangement of valves,
the flow of water being uninterrupted, for the current is not stopped but
only diverted to the opposite sides of the piston at cach change of the
valves; for as the valve Va shuts, exactly in like proportion the valve V
opens, and the reverse. These ends may be attained by different forms
of valves, such as common clack or hinge valves, worked by a tappet on
the piston rod. I therefore do not confine my Invention to any particular
form of single valve, but merely the arrangement of valves. I, however,
recommend the form of valve described as giving a large opening for a small
motion, and I claim as my Invention the so arranging and combining of four
distinct valves connected by a spindle or a series of jointed rods, as the case
may require, in such a manner that the pressure on the back of one valve
counteracts the pressure upon the other, and also that as one valve communi-
cating with the head of water shuts, exactly in like proportion the other valve
opens, thus preventing the flow of water from being arrested, and thereby causing
a concussion, but merely diverting the direction of the flow of water to the
opposite sides of the piston
In witness whereof, I, the said Francis. Hastings Greenstreet, have
hereunto set my hand and seal, this Thirtieth day of May, in the year.
In witness whereof, I, the said Francis. Hastings Greenstreet, have
hereunto set my hand and seal, this Thirtieth day of May, in the year.
of our Lord One thousand eight hundred and forty-nine.
FRANCIS HASTINGS (L.s.) GREENSTREET.

page_text: AND BE IT REMEMBERED, that on the Thirtieth day of May, in the
year of our Lord 1849, the aforesaid Francis Hastings Greenstreet came
before our said Lady the Queen in Her Chancery, and acknowledged the
Specification aforesaid, and all and every thing therein contained and specified,
in form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute made for that purpose.
Enrolled the Second day of June, in the year of our Lord One thousand