Improvements in Direct Acting Pumps.
Year: 1897

page_text: Date of Application, 4th Dec., 1897-Accepted, 8th Jan., 1898
Improvements in Direct Acting Pumps.
We, JOHN ROBERT BIRD, Engineer, and ROBERT RICHARDSON, Engineer, both
of 10 Morrison Street, in the City of Glasgow, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:
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This Invention relates to direct acting pumps and it has for its object to
provide a valve mechanism for the pump, which shall so control the admission
and exhaust ports, that the piston shall reverse easily and the shock upon the
pump shall be minimised.
The Invention is illustrated by the accompanying drawings, Fig. 1 being a
vertical section on the line ac, Fig. 2; Fig. 2 a horizontal section on the
line yy, Fig. 1; Fig. 3a vertical section on the line ww, Fig. 1; and Fig. 4
a vertical section on the line -, Fig. 3. Fig. 5 is a plan and Fig. 6 an inverted
plan of the moving port face, and Fig. 7 is a plan of the distributing valve.
Figs. 8 and 9 are vertical and horizontal section on the lines u-u, t-t, respectively
showing a modified form of pump in which a single auxiliary passage and regu-
lating cock is used, and Fig. 10 shows another modification in which four auxiliary
passages and regulating cocks are used to minimise the shock and effect the easy
reversal of the pump.
In carrying out the Invention we provide a valve block or moving port face A
having a continuous movement in the same direction as the piston 13 of the steam
cylinder C, this block A acting as an auxiliary valve and being constantly sur-
rounded by pressure steam. Inlet ports A2, A3, and an exhaust port A¹ are
formed in the valve block A, which communicate with the passages F, G, leading
from the cylinder port face C to opposite ends of the cylinder; and the block Ä..
is further provided with recesses A7, A, and ports A8, A10, communicating there-
with by which steam is supplied to the interior of a distributing valve H. This
distributing valve consists of a cylinder H having a sliding face H' in which an
exhaust cavity H2 is formed which serves to put the ports A2, A3, in the valve
block A alternately in communication with the exhaust port A formed in said
valve block, the exhaust port communicating with an exhaust outlet M. The
distributing valve is also provided with small ports H³, H', extending from its
sliding face to the interior of the cylinder H. Within the cylinder H a piston H5
is fitted, the rod He of which is held between two vertical arms A' on the valve
block A, the cylinder moving upon the piston as hereinafter described. The inlet
ports A2, A3, in the valve block A have small ports A, A, extending from them
to the sliding face of the valve block A these ports A5, A6, communicating periodi-
cally with auxiliary passages F, G, extending from the passages F, G, in the
cylinder C to the cylinder port face C₁, the passages F, G, being preferably
fitted with cocks F², G², which admit of regulating the inlet or outlet of steam.
:.

page_text: The cocks are capable of being regulated from the outside as shown at Figs. 2
and 3. The valve block A is provided with a rod J carried through the valve
casing K and connected to the piston rod of the steam cylinder as shown. The
valve casing K is provided with projections K' to act upon the distributing
valve H. to stop it whilst permitting of the further travel of the block A,.
The action of the pump is as follows:-
When the piston B is in the position shown at Figs. 1 and 4, that is to say,
almost at the top of its stroke, steam is passing from the valve casing through
the port A3 in the valve block A and by way of the small port A6 extending from
it through the auxiliary passage G₁ to the passage G leading to the lower end
of the cylinder C thus supplying: this side of the piston B with terminal steam.
The steam on the upper side of the piston is exhausting by way of the auxiliary
passage F through the port A³ in the valve block A and the exhaust cavity 12
in the distributing valve H to the exhaust port A4 and outlet M, the passage Fl
being closed to any desired extent in the manner already described. At this
instant the travel of the distributing valve H is stopped by the projections K'
on the casing K and the recess A7 formed in the valve block A from which the
small port As branches is on the further travel of the block A opened to the steam
contained in the valve casing K, which steam passes by way of this port A8
through the port H³ into the interior of the distributing valve cylinder H. where
it acts on the piston H5 of this valve. This steam traverses the valve cylinder H
so as to open the port A3 of the valve block A to steam from the casing K, which
steam passes by way of the auxiliary passage F1 to the passage F leading to the
upper end of the cylinder C, and at the same time it open the passage G to
exhaust, this movement of the distributing valve supplying initial steam to one
end of the cylinder C and permitting an initial exhaust at the other end whereby
the reversal of the steam cylinder is effected without shock.
In the modification illustrated by Figs. 8 and 9 instead of forming auxiliary
passages in the inlet ports A2, A3, of the valve block A a single auxiliary
passage A is formed in the exhaust port A' in the valve block A which com-
municates with an auxiliary passage M¹ in the exhaust outlet M, said passage M¹
being fitted with a cock M2 capable of being regulated from outside of the pump.
This cock acts to minimise the shock upon the pump by throttling the initial
and terminal exhaust steam only.
In the modification illustrated by Fig. 10, four passages F3, F4, and G3, G4,
are formed extending from the port face C¹ of the cylinder C to the passages F
and G respectively, the former passages being preferably fitted with cocks as
already described with reference to Figs. 1 to 7. In this case the small
ports A5, A6, in the valve block A are dispensed with.
Having now particularly described and ascertained the nature of our said
Invention, and in what manner the same is to be performed, we declare that what
we claim is :-
1. A direct acting pump the parts of which are constructed combined and
arranged to operate substantially as described.
2. In a direct acting pump. the combination with the herein before described
steam distributing valve of a moving port face or auxiliary valve constructed and
arranged to operate substantially as described.
3. In a direct acting pump the combination with a steam cylinder having
auxiliary passages open to the steam and exhaust passages of a sliding block or
moving port face arranged and operated to cover and uncover said auxiliary
passages substantially as and for the purpose set forth.
4. In a direct acting pump the combination with a sliding block or moving
port face, of auxiliary passages extending from the port face of the steam cylinder
and communicating with the steam passages of said cylinder, and cocks fitted
in these auxiliary passages capable of being regulated from the outside of the
2
5

page_text: valve casing to control the initial and terminal steam or exhaust or both, sub-
stantially as described.
Dated this 3rd day of December 1897.
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank and Fairweather,
Chartered Patent Agents,
62, Saint Vincent Street, Glasgow, Agent for the Applicants.