Improvements in or applicable to Cut Off Valves for ' Steam Engines.
Year: 1895

page_text: Date of Application; 17th June, 1895-Accepted, 3rd. Aug., 1895
COMPLETE SPECIFICATION.
Improvements in or applicable to Cut Off Valves for
'
Steam Engines. *:
We THOMAS.LEES, and RALPH LEES, both of Park Foundry, Hollinwood, near
Oldham in the County of Lancaster, Engineers, do hereby declare the nature
of this invention and in what manner thie:same is to be performed.to.be particularly
described and:ascertained in and by the following statement:―
Our said invention relates to improvements in the means for varying the cut off
of the steam. when steam engines are worked expansively.
The cut off valve works on the back of the main steam valve: and controls the
admission of steam to the 'latter.
In order to more clearly describe our said invention we have appended three
sheets of drawings to which reference is hereinafter. made.
Fig. 1.is an elevation partly in section of our invention as applied to a vertical
engine in which the point of cut off is controlled by hand.
Fig. 2 is a similar view showing the cut off controlled automatically by the
governor.
Fig. 3 is a similar view to Fig. 2 showing our invention as applied to a reversing
engine.
in all the figures the same letters refer to the same parts.
According to our said invention we divide the cut off valve into two parts
a and b (Fig. 2) each operated by separate spindles a¹¹. The spindle b' of the rear
cut off valve passes through an opening a² of the front cut off valve and slides freely
herein. By this arrangement each cut off valve may be used of the full available
width of the steam valve c.
The spindles 6 and a¹ of the cut off valves are parallel and are connected at their
outer ends to the side arms d¹ d² of a T lever pivoted in a slide bar e operated
through the connecting rod e¹ by the cut off excentric.
When the cut off is controlled by hand the middle arm d³ is connected by a link f
to a screw and hand wheel f1f2 (Fig. 1). By turning the hand wheel f' the T lever
is caused to turn about its fulcrum in the slide e and by this means the cut off
valves a and b are caused to approach to or recede from each other and by this
means the point of cut off is varied.
When the cut off is automatically controlled by the governor as in Fig. 2 the
link is connected by a bell crank lever g to the sleeve of the governor and as the
latter rises or falls the angular position of the arms d' d² with regard to the direction
of motion of the slide e is varied.
When our said invention is applied to a reversing engine two excentrics and a
link motion are provided as shown in Fig. 3 for operating the main steam valve
while the cut off valve is operated by its own excentric preferably placed between
the main valve excentrics.
The cut off valves a and b are adjusted by the ends of their spindles being
screwed and provided by adjusting nuts taking into brackets a³ 63 on the links a b
which connect the valve spindles to the opposite arms d' d² of the T lever (Fig. 2).
In the illustrations our said invention is shown as applied to piston or cylindrical
cut off valves. Fig 4 is a section of the valves at right angles to Fig. 1 and Fig. 5
is a plan of the valves. In these figures c is the main steam valve having annular
steam ports c' c² over which the cut off valves a and b work.
reception of the main valve rod passes through the main steam valve and fitting
A tube for the

page_text: tight into the ends of the main valve prevents the escape of steam before reaching
the valve face. Our said invention is however applicable to other shapes of divided
cut off valves, and by an obvious modification of the parts is also applicable to
horizontal or other types of engines as well as to vertical engines.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is.―
1. A cut off device for steam engines constructed and operated substantially as
herein before set forth and shown.
2. A divided cut off valve for a steam engine so constructed that the valve
spindle of the rear valve passes freely through the other valve substantially as set
forth and shown.
3. The combination of a divided cylindrical cut off valve with a main valve
having annular ports and steam passages traversed by a tube for the reception of
the main valve spindle substantially as set forth and shown.
4. The combination of a divided cut off valve one of whose spindles passes
through the other valve and a sliding T lever connected therewith and operated
by the cut off excentric and provided with means for varying its inclination
substantially as and for the purpose set forth and shown.
Dated this 14th day of June 1895.
E. T. WHITELOW, A.M. Inst. C.E.,
70 Deansgate, Manchester, Agent for the Applicants.