Year: 1888

page_text: Date of Application, 11th Feb., 1888
Complete Specification Left, 11th Dec., 1888
Complete Specification Accepted, 5th Feb., 1889
We ELIOT HODGKIN and PHILIP ELIOT HODGKIN both of Nine Elms Iron
Works, Nine Elms, in the County of Surrey, Engineers do hereby declare the nature
of this invention to be as follows:-
Our Invention relates to pumps of that class in which the water or other liquid is
ejected by the direct action of steam thereon without the intervention of a piston or
similar contrivance, and in which two or more working chambers are employed
to which the steam is admitted alternately or in turn by means of a distributing
valve or valves such for example as a ball or its equivalents.
According to our Invention, we employ, for the purpose of economizing by
expansion the amount of steam consumed at each stroke, in combination with the
distributing valve or valves (of whatever type) of such pumps, a cut-off valve or
valves of the type described in the specification to Letters Patent granted to Ernst
Heinrich Greeven dated the 27th April 1882 No. 1988, or any other suitable
cut-off valve or valves, whether actuated by difference of pressure or otherwise,
such cut-off valve or valves being by preference placed above the distributing valve
or valves so as to regulate the supply of steam thereto, cutting it off at the point
desired, earlier than would have been the case if the cut-off valve or valves had not
been employed.
1030
THOS. J. HANDFORD,
50, Bedford Row, London, W.C.,
Agent.

page_text: Improvements in Steam and Vacuum Pumps.
We ELIOT: HODGKIN and PHILIP ELIOT HODGKIN, both of Nine Elms Iron
Works, Nine Elms, in the County of Surrey, Engineers, 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 :-
Our invention relates to pumps of that class in which the water or other liquid is
ejected by the direct action of steam thereon without the intervention of a piston or
similar contrivance and in which two or more working chambers are employed to
which the steam is admitted alternately or in turn by means of a distributing valve
or equivalent valves such for example as a ball.
According to our Invention we eniploy, for the purpose of economizing by expan-
sion the amount of steam consumed at each stroke, in combination with the
distributing valve or equivalent valves of such pumps, a cut-off valve which is
liereinafter referred to as an expansión valve.
The use of expansion valves has long been known in connection with steam and
other engines. Hitherto however it has not been found practicable to apply
expansion valves to double-chambered pumps of the class hercin referred to. The
nearest approach to the use of such a valve of which we are aware is to be found in
the apparatus described in the specification of Davis' Patent No. 154 A.D. 1879.
But in this apparatus the motion of the cut-off valves is determined by the emptying
of the pump chamber into which the steam is passing and hence the cut-off valve does
not operate until the chamber is filled with steam and the water is discharged
therefrom. Hence this cut-off valve does not act as an expansion valve. Moreover
this cut-off valve is operated by an arrangement of levers, tappets and the like which
would in practice be highly objectionable and unsuitable to the practical conditions under
which such pumps are required to work.
It will be seen that in order to secure the results at which we aim it is necessary
that the motions of the expansion valve should be so timed or adjusted in relation to
those of the distributing valve that the expansion valve may cut off the steam when
one of the chambers is (say) half emptied and keep it cut off whilst the remainder of
the chamber is being emptied, the distributing valve being unmoved during this
period, and that at the end of this period the expansion valve should re-open with or
immediately after the distributing valve to admit stean into the other chamber, and so
on.
In pumps where a mechanical connection between the moving parts or a positive
actuation of the valves is permissible such a combined operation could be readily
secured in a variety of ways. But by our invention we secure the required combined
operation of the expansion and distributing valves, with the saine certainty of regular
periodical working as if the valves were mechanically connected or positively actuated,
yet without the use of any objectionable valve-gear. In our invention the motions of
the distributing valve are determined as heretofore by the differences of pressure in
the pump chambers, whilst the motions of the expansion valve are determined by

page_text: another set of differences of pressure which are so far dependent on the pump chamber
pressures as to give the required combined operation of the expansion and distributing
valves, but so far independent of the pump chamber pressures as to permit of the
motion of the expansion valve being timed so as to secure the required degree of
expansion or point of cut off.
In the form of our apparatus which we prefer, we use, as an expansion valve, the
differential valve described in the specification of Greeven's patent No. 1988
A.D. 1882. This valve is operated by differences of pressure within and without a
special chamber and hence, when used as an expansion valve, permits of being
regulated in relation to the distributing valve so that it closes independently of the
motion of the distributing valve and opens conjointly with the distributing valve.
There exist also various kinds of differential pressure regulating valves, such for
instance as have been used for regulating the supply of gas, in which the motions of
the valve are determined by differences of pressure within and without a special
chamber in connection with the valve, and which by being modified so as to make
them actually shut off the supply for a definite period might also be used in com-
bination with a distributing valve in accordance with our invention.
We proceed to describe our invention more fully with reference by way of example
to the well known pumps of the class hereinbefore referred to which are manufactured
by the Pulsometer Engineering Company Limited. In these pumps as ordinarily
made there are two pump chambers to which steam is admitted alternately through
the medium of a ball distributing valve, which is operated by differences of pressure
in the two pump chambers in a well known manner. Such a pump with
various modifications is described in the specification of Letters patent No. 2885
A.D. 1872.
In the drawings hereto annexed the lower part of figure 1 represents a portion
of such a pump, which is of the ordinary construction except in the following respect.
When such a pump is worked expansively by the use of an expansion-valve as
herein described, it is found that the time taken to empty a chamber is generally
greater than the time taken to fill a chamber. It is necessary to the proper
combined working of the expansion and distributing valves, that the movement of
the distributing valve to open the filling chamber and close the emptying chamber
should be delayed until the steam, after it is cut-off by the expansion valve, has
time to expand and sufficiently empty the chamber. This result may be attained
by arranging the distributing valve C, with a sufficiently long travel to delay tho
motion of the distributing valve till the emptying chamber is nearly empty. With
this exception, the portion of the apparatus below the line A, B, is of the ordinary
construction above referred to. A stop a is placed above the distributing valve to
prevent its being thrown violently up by the sudden pressure which is sometimes
produced by the momentum of the water rushing into the pump chambers.
The upper part of Figure 1 above the line A, B, shows the expansion valve
placed in the steam-way to the distributing valve. The movable part fis free to
slide up and down within the fixed part so as to close and open the mouth &
of the steam inlet b. Small holes g, g¹, are provided for the admission and escape
of steam into and from the special chamber F. kk are small circular diaphragms
turning on pivots and having a circular row of holes of different sizes. One of these
diaphragms is shown in plan enlarged in Figure 2. It will be seen that the opening
and closing of the expansion valve will be determined by the differences of pressure
within and without the special chamber F, and that the sizes of the openings g g', as
adjusted by the diaphragms will determine the periodicity of the motions of the
expansion valve and enable it to be timed so as to cut off the steam supply at
the required point before the distributing valve moves and open conjointly with the
distributing valve.
The operation of the combined valves is as follows:-Commencing at the moment
when the left hand chamber d is full of water and the distributing valve C has moved
to close the right hand chamber e and open the left hand chamber d, the expansion
valve being open, the full steam pressure enters the left hand chamber d and (say)

page_text: half empties it. During this time, steam has been entering the special chamber F
through the orifices g and g¹, thereby increasing the pressure therein and as the water
falls there is a reduction of pressure without the chamber, the effect of which is to
cause the movable part of the expansion valve to rise and cut-off the steam. The
expansion of the steam and expulsion of the water continues until the chamber is
nearly emptied, when the difference of pressures in the pump chambers brings over
the distributing valve C. By this time the escape of the steam from the chamber F.
permits the pressure of steam in the steam pipe b to depress the movable part of the
valve and the steam rushes in to expel in turn the water which has flowed into the
right hand chamber during the emptying of the left hand chamber. It will be thus
seen that the action of the apparatus depends on the proper timing of the motions of
the expansion valve with reference to the motions of the distributing valve.
This is effected by the adjustment of the orifices g, g' by means of the
diaphragmsk, k₁, or in some equivalent manner, with reference to the conditions
under which the pump is to work, the requisites being that the orifices should
be so regulated that the movable part of the valve closes at some point-
during the emptying of a chamber so as to permit the steam to work expansively
during the latter portion of the stroke, and opens again when it is nearly empty
conjointly with the distributing valve.
Pumps of this class are generally supplied to meet given conditions of steam
pressure, lift and the like, and hence we propose in most cases to dispense with the
diaphragms k, k, the orifices g and g¹ being proportioned to meet the given conditions
of working in accordance with the principles above described. Figure 3 shows such
a pump properly proportioned on a scale of one half the actual size intended to work
at 50 lbs. pressure of steam. The orifice y is 6th inch in diameter and the orifice g¹
about twice that size and a saving of about 40 per cent. of steam is effected as com-
pared with a pump of the same size without any expansion valve.
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
In pumps of the kind hereinbefore described, the use of an expansion valve
arranged and operating in conjunction with the distributing valve, substantially as
herein before described.
1 of Dacouba 1898