Improvements in Pumps.
Year: 1899

page_text: Improvements in Pumps.
I, FREDERICK EDWARDS, of 62, Bishopsgate Street Within, in the County of
London, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention has reference to improvements in air pumps part of the said
invention being applicable to pumps of the kind described in the Specifications
of my former Patents No. 5175. of 1894, No. 9653 of 1896 and No. 21034 of
1896.
To enable an air pump (and more particularly one in use with a jet condenser)
to work more satisfactorily at high speeds with reduced shock or concussion,
in place of the ordinary snifting valve which admits air to the pump I provide
an air inlet so controlled that air will only be admitted to the barrel whilst the
pump bucket is making a discharge stroke. The snifting valves generally in
use at the present time for admitting air will admit air into the pump, at any
time, .e. whenever the pressure in the pump is sufficiently below that of the
atmosphere, to cause it to flow in. The result of this arrangement is that
at the very time when the lowest pressures would and should be obtained in
the pump in order to cause the greatest amount of air to flow from the con-
denser into the pump, air is flowing directly from the atmosphere through the
snifting valve into the pump, thereby destroying the vacuum and raising the
pressure in it and consequently reducing its efficiency. The only time during
which air can have a beneficial effect on the action of an air pump is during its
discharge, and air admitted during the suction stroke does harm because it
reduces the vacuum in the condenser. Now according to my invention there
is provided a fitting or apparatus by which air is allowed to flow into the pump
during the first part of the discharge stroke but is not allowed to flow in during
the suction stroke, the result being that its beneficial effect is obtained without
the usual drawbacks, i.e. the air is admitted after the pump has drawn all it
possibly can from the condenser, after it has commenced the discharge stroke
and when all communication with the condenser has been shut off: after all
this has taken place, and before the pump commences to discharge I admit the
I have several methods by which this desired result can be brought about;
in one of them I form a communication between the atmosphere and the upper
part of the barrel (it may be immediately beneath the valves), said communi-
cation being provided with a valve similar to the ordinary snifting valve, and
leading into the barrel immediately under the head valve. This valve forms
a non return valve: its use, however, is not a necessity, but, in order to save
fine adjustment, may be a convenience.
air.
In the passage leading from the pump barrel to the atmosphere I fit, accord-
ing to this invention, a slide valve, by which the admission of the air is con-
trolled and regulated as required.

page_text: This slide valve travels in guides and is worked by a piston or plunger though
the piston is not coupled rigidly to it. The slide valve has a cylinder formed
in the back of it in which the piston or plunger works. The piston or plunger
may be coupled to and operated direct from the engine or pump crosshead by
means of a rocking lever and links. The cylinder has a port or ports leading
to the face of the slide valve and from there through the snifting or non return
valve into the air pump barrel and the cylinder has also openings leading to
the atmosphere. These latter ports are so arranged that, when air is required
to flow through the other ports in the cylinder to the face of the slide valve,
the air can easily pass through those. admitting the air from the atmosphere
to the cylinder, and the ends of the cylinder are practically closed so as to con-
fine the air in them and enable the piston by means of the compressed air to
drive the cylinder and slide valve, in other words the ends of the cylinder are
similar to moving dashpots.
The piston and cylinder are so constructed that (assuming the pump to be
working slowly) the piston must travel a certain distance in the cylinder before
it can move the latter and when moving this distance it either opens or closes
the port or ports leading to the face of the slide valve. During the first part
of the suction stroke of the pump the piston travels in the cylinder of the slide
valve, covers. the port or ports, compresses the air and then sets the slide valve
in motion and consequently when the ports in the faces of the slide valve are
passing the one over the other no air is admitted owing to the port in the
eylinder being covered by the piston.
During the first part of the discharge stroke of the pump, the piston uncovers
the port or ports in the cylinder leading to the face of slide valve and also the
port leading to the atmosphere, compresses the air in the other end of the
cylinder, sets the valve in motion and consequently, when the ports in the faces
of the slide valve are passing one another, there is a free admission for the air
into the pump barrel; whereupon air will, if the pressure in the pump barrel
be below that of the atmosphere, pass through the cylinder to said inlet port
and past the non-return valve into the pump barrel where, acting as a cushion
between the pump bucket and the cover of the barrel and its discharge valves,
it will, as is well known, tend to prevent concussion. If the pump be working
at a high speed, the action may, owing to the inertia of the slide valve, be some-
what modified. The air thus admitted will be driven through the discharge
valves with the water and, as the pump bucket makes a return suction stroke,
the piston will also make a return stroke in the cylinder of the slide valve and
thereby move it, the piston first closing the port in the cylinder leading to the
valve face as previously described; it also releases the air at the one end and
encloses air at its other end, which serves as a cushion, Thus no air is allowed
to enter the pump barrel during the suction stroke, whilst a vacuum is being
formed therein or whilst it is in communication with the condenser, the pres-
sure in which can therefore be reduced below pressures obtainable by means of
pumps fitted with snifting valves in the ordinary manner. The piston rod may
be made adjustable and the effect of the air cushions between the piston and the
valve cylinder ends may be varied by means of escape orifices which can be
closed more or less by screws so as to regulate the movement of the slide valve.
Other methods by which I obtain these desirable results are by using other
mechanical arrangements, such as tappets and contacts or any other device
which will admit air on the one stroke and not on the other, and the same result
may also be obtained by making use of the force imparted to some of the water
during the descent of the bucket.
Another defect in the ordinary air pumps of the present day consists in the
form of the upper portion of the barrel and bucket and the construction and
position of the valve and seats in relation thereto. For instance the top of the
bucket and underside of the head valve seat as ordinarily constructed are flat,
and the valves are placed as conveniently as may be practicable and without

page_text: regard to the direction in which the water should flow to avoid concussion and
without any attempt being made to give the water any particular direction
of flow, or to reduce the number of changes of direction and thereby save con-
cussion. The result of this arrangement is that when the bucket is rising
with a layer of water on it, the surface of the water strikes the underside of
the seat which is immediately round the rod, and also the other portions of
the cover and seat between the valve openings without any definite tendency
being given mechanically to it to travel in any particular direction and without
any immediate opportunity of release, that is to say in vertical pumps a direct
upward blow is struck on these parts of the valve seat or cover with the natural
result of a direct rebound on to the bucket and before the water can escape,
the energy due to its upward movement has to be destroyed and the water
has to commence travelling in a fresh direction (viz. horizontally and at right
angles to that at which it was travelling before) until it comes under one of
the openings in the valve seat, and then it comes into. violent collision with
other water travelling towards the centre of the same opening but in exactly the
opposite direction. It will thus be seen that the water round each of these
openings will be travelling towards the centre thereof and that the nearer it
gets to this centre the more difficult it becomes in constructing the pump to
provide sufficient outlet area and that there is a great confusion of currents.
Its direction has then to be again changed and it has again to commence
travelling at right angles to the last direction it was moving in, viz. in a
vertical direction, it then reaches the underside of the valve and once more it
has again to commence travelling at right angles to its previous movement
and, after all these changes, it at last escapes out of the pump barrel. Again,
if the pump should happen to contain air under the before mentioned parts
there is no direct mechanical action of the water tending to drive it out, i.e. water
may escape through the valves, but the spaces not immediately under them
may contain air and the clearance at these parts may remain full of air at the
completion of the stroke. The result of all these rebounds and changes of
direction is waste of power, concussions and knocks, and they make it impossible
to drive the pump at high speeds without rendering the working conditions:
unsatisfactory.
Now according to my invention these direct rebounds and abrupt changes
of direction are obviated, for which purpose the pump is so constructed and the
discharge valves are so placed and arranged that previous to or about the com-
mencement of the discharge, a portion of the water is set travelling by local
pressure in the pump and prior to pressure equal to this local pressure occurring
throughout the whole capacity of the pump, partly through space not occupied
by water, in nearly the direction in which it will ultimately have to flow out
of the pump, and the amount of water thus set in motion is gradually increased
and its speed gradually accelerated in the direction of the valves; that is to say,
the discharge valves are so placed and arranged that water set in motion by
the bucket and striking the upper parts of the pump will, in the first instance,
be deflected and set travelling more nearly in the direction in which it will
ultimately have to escape.
As in my construction I endeavour to make the water travel in a continuous
radial direction and from one common centre viz. the centre of the pump, out-
wards it becomes easier to provide space for it to travel through and the con-
cussions are reduced.
In one arrangement the pump is formed with a flared or enlarged upper part,
which portion may be formed partly or wholly in the cover or barrel or partly
in one and partly in the other, and the cover may extend into the cylindrical
portion of the barrel and the valve seat or cover has in it a series of valves or
outlet apertures, the walls of which and the top of the barrel are so arranged
that they will not abruptly change the direction of the water; these openings
may be wholly or partly beyond the cylindrical portion or bore of the barrel.

page_text: The bars which form the gratings or valve seats and which divide up the out-
let openings and support the valves, may be arranged radially to the axis of
the pump barrel instead of radiating from their own centres or the centre
of each outlet opening as usually constructed at the present time; that is, the
bars may be so arranged that the water in passing between them travels in the
direction of their length and the flat sides of none of them are placed at right
angles to said direction. The bars are preferably of decreasing width towards
their lower edges, the arrangement being such as to gradually divert the water
to the openings between them without abrupt change of direction. The outlet
openings may be circular and fitted with disc-like valves of ordinary kinds,
or they may be of curved or segmental form provided with rubber or other
flap valves secured to their seats at their inner edges.
As will be easily understood it is not the speed at which water travels which
causes shocks, but that they are due to suddenly starting and stopping it and
also to rebounds and sudden abrupt changes in direction which lead to such
unsatisfactory working conditions; consequently, if these can be avoided the
pump can be driven at higher speeds. The action of the pump con-.
structed in accordance with my invention is as follows:-
-The water
on the centre part of the bucket round the rod, which is farthest from the valve.
openings, is the first to come in contact with the cover and the first to be set in
motion and owing to the angle at which it strikes the cover, it is at once set
travelling in an outward or radial direction, and, whilst so doing, will or may
come in contact with other water travelling in a vertical direction; the
resultant of these two forces will or may be one having an outward, upward
radial direction which causes the water to flow towards and through the valve
openings with practically speaking no abrupt change of direction.
With this construction, it will be seen that if any air exists under those
portions of the barrel cover which have not openings in them, as for instance,
near the rod, there is, owing to the movement of the water, a direct mechanical
action tending to drive it radially towards the outlet openings.
In some cases, the top surface of the bucket is made so as to fit close up
against the cover on the completion of the discharge stroke; in other cases,
the clearance between the bucket and the cover may gradually increase towards
the wall of the barrel. The cover may be concavely conical in form, i.e. its
under side, as seen in central vertical section, may have a curved conformation
instead of being of truly conical form; the top of the bucket may be similarly
formed.
For some requirements or conditions, I may make that portion of the bucket
near the circumference convex, the object being that in pumps working in
connection with surface condensers, or where the amount of water dealt with
is small, this convex part may increase the depth of the water seal, that is to
say, the form of the cover at the top of the barrel is not, at this part, similar
in form to the top of the bucket, consequently the clearance at this part is
increased and, as a natural result, there is, in vertical pumps, more water left
in the pump barrel over this part of the bucket at the end of the discharge
stroke than there is over the other parts, which water is available for increasing
the depth of the seal during the next up stroke.
In pumps which have to deal with large quantities of water, the same form
may be retained for this part of the bucket top but, instead of the clearance
being increased at this part, the underside of the cover may be brought down at
a corresponding angle to that of the top of the bucket, thereby considerably
increasing the depth of the cover at this part, the object of this being to enable
it to be so formed as to cause the water to travel more gradually in the way in
which it will ultimately have to pass out. This improvement is specially
designed for dealing with the water which would otherwise strike a blow on
the more or less flat surfaces which would be left between two valve seats and
this increased depth of valve seat, if made to coincide with the bucket at this

page_text: part, enables the undersides of such intermediate parts to be more acutely.
chamfered or tapered and the water to be more easily or gradually diverted,
half to one adjacent opening and the other half to the other adjacent opening,.
thereby reducing the shock which would otherwise have occurred at this part.
The convex part of the bucket when approaching the end of the stroke has also
natural tendency to set the water travelling in the direction in which it is
desired it should flow out of the pump. As will be understood, with such an
arrangement not only is shock lessened or prevented but the water can flow
out more easily.
Although vertical pumps have been referred to herein this invention applies
in part to horizontal pumps.
Improvements in rumps.
1, FREDERICK EDWARDS, of 62, Bishopsgate Street Within, in the County of
London, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
This invention has reference to improvements in air pumps, more particularly
those of the kind referred to in the Specifications of my former Patents No. 5175
of 1894, No. 9653 of 1896 and No. 21034 of 1896, objects being to increase the
effectiveness of such pumps without the occurrence of shock or concussion.
Referring to the accompanying illustrative drawings Fig. 1 is an elevation
of an air pump according to this invention;
Fig. 2 a vertical section on the line A A Fig. 3 of such a pump drawn to a
larger scale;
Fig. 3 a section on the line B B Fig. 2 with the valve seat removed in the
lower half of the figure.
Fig. 4 a longitudinal section illustrating an apparatus for controlling the
admission of air to the air pump barrel for cushioning purposes; and
Fig. 5 a plan of said apparatus.
The pump illustrated is a steam engine air pump of the kind referred to in
the specifications of my before mentioned patents; it comprises a barrel a formed
with valveless inlet ports or openings b, a valveless bucket c adapted to serve.
as a piston valve; and a chamber & which is in communication with the con-
denser and whence the descent of the bucket displaces the water and causes it
to pass through the inlet openings into the barrel above the bucket, as well
understood.
To enable the pump to work satisfactorily at high speeds without shock or
concussion, in place of the ordinary snifting valve, I provide a fitting or
apparatus. whereby air is only admitted to the barrel whilst the bucket is
making a discharge stroke so that the efficiency of the pump is not reduced
by the admission of the air necessary for cushioning purposes, because such air
is not admitted to it until it has drawn all it can from the condenser and com-
munication therewith has been closed.
The construction of the apparatus f. shown in Fig. 1 is illustrated to a larger

page_text: The
scale in Figs. 4 and 5, wherein 1 is a passage which forms a communication
between the atmosphere and the upper part of the pump barrel, immediately
under the delivery valve. The wall of the passage 1 is formed with a valve
face 1 on which works a slide valve 2 that travels in guides 3 and is actuated
by means of a piston 4 arranged in a cylinder 5 in the back of the slide valve 2.
The piston 4 has a rod or spindle G that works through a stuffing box 7 and
may be coupled to the rocking lever g by a link has shown in Fig. 1.
cylinder has ports 8 leading to the working face of the slide valve 2, and corre-
sponding ports 9 lead from the valve face 1 to the passage 1. The cylinder
has other ports 10 which lead to the atmosphere and are so arranged that, when
air is required to flow through the ports 8, can easily pass to them from the
atmosphere through the ports 10 and the cylinder 5. The cylinder 5 is closed,
at its respective ends, by the stuffing box 7 and plug 11 so as to enable the
piston 4 to drive the cylinder and slide valve by means of the air. confined in
the end portions of the cylinder, which are similar to moving dashpots. Holes 12
permit the piston to move to the required extent before actuating the valve.
13 is a spring which by means of an adjusting screw 14 presses the slide valve 2
against the face 1ª with more or less pressure, a saddle 15 being interposed
between the spring and the back of the slide valve.
The piston 4 and cylinder 5 are so constructed and arranged that the piston
must travel a certain distance in the cylinder before it can move it, and in
moving this distance, either opens or closes the ports 8. During the first part
of the suction stroke of the pump, the piston 4 travels downwardly in the
cylinder 5, covers the ports 8 and the lower holes 12, compresses the air in the
lower end of the cylinder, and sets the slide valve 2 in motion; then, as the
ports 8 pass the ports 9 no ai will be admitted through them to the passage 1
owing to the port 8 being covered by the piston.
During the discharge stroke of the pump, the piston 4 first moves upwardly
in the cylinder, uncovers the ports 8 and, having covered the upper row of
holes 12, compresses the air in the upper portion of the cylinder 5 and sets the
slide valve 2 in motion; so that the ports 8 have to pass over and beyond the
ports 9; consequently, as the ports 8 pass the ports 9 in an upward direction
there will be free communication between the atmosphere and the pump barrel
for a given period and air will, if the pressure in the pump barrel be below that
of the atmosphere, pass through the ports 10, 8 and 9 and the passage 1 into
the pump barrel, where, acting as a cushion between the pump bucket and the
cover of the barrel and its discharge valves, it will, as is well known, tend to
prevent concussion. The air thus admitted will be driven through the discharge
valves with the water and, as the pump bucket makes a return suction stroke,
the piston 4 will also make a return stroke in the cylinder 5, and will close the
ports 8 before they come opposite the ports 9 as the valve 2 is moved downwardly
as previously described. Thus no air is allowed to enter the pump barrel
during the suction strokes, that is to say, whilst a vacuum is being formed in
the barrel, or whilst it is in communication with the condenser, the pressure
in which can therefore be reduced below pressures obtainable by means of
pumps fitted with snifting valves in the ordinary manner. The effect of the
air cushions between the piston 4 and the valve cylinder ends may be varied
by more or less closing cocks or valves (not shown) fitted thereto. The passage 1
may, in some cases, be provided with a non-return or snifting valve 10 the lift
of which can be varied by means of a screw spindle 17, the said valve serving
to prevent the escape of the cushioning air or water as the pump bucket nears
the end of its discharge stroke, so that it to some extent obviates very accurate
fitting and adjustment of the controlling valve 2 and its appurtenances
Instead of the arrangement herein before described, other mechanical arrange-
ments, may be employed; for instance, tappets and contacts, or any other device
which will cause air to be admitted on the one stroke and not on the other. 'Also
the force imparted to the water during the descent of the bucket as described

page_text: in the specifications of my before-mentioned patents may be made use of to
effect the same purpose.
Fig. 6 shows in longitudinal vertical section a modified arrangement for
controlling the admission of air to the pump barrel for cushioning purposes.
20 is a valve controlling the passage 1 and normally kept closed by a
spring 21; the valve is arranged to be lifted from its seat so as to admit air to
the pump barrel on the discharge stroke of the pump bucket by suitably
driven tappet gear. In the example, the valve can move to a limited extent
lengthwise of its spindle 23, which is provided at its lower end with a collar 24
held within a stirrup piece 25 formed in one with the valve. To the spindle 23
is pivoted a rod or link 26 formed, at its free end, with a catch or tooth 27
kept by a spring 28 in the path of a projection 29 on a rod 30 that is attached
to the pump crosshead or is otherwise driven.
As the bucket makes its suction stroke, the rod 30 descends with it and the
projection 29 pressing to one side the link 26 rides over the tooth 27, the
valve during this stroke, being held closed by its spring 21, which is suffi-
ciently strong for this purpose; during the discharge stroke of the pump
bucket the rod 30 rises, its projection 29 engaging with the tooth 27 and then
lifting the valve 20 in opposition to the spring 21 so as to allow air to enter
the pump barrel through the passage 1. 20 is a fixed roller against which
the link 26 is caused to bear by its spring 28 and which, upon the continued
upward movement, forces the tooth 27 out of engagement with the projection 29,
whereupon the spring 21 closes the valve 20 and restores the parts to the
positions shown.
Figs. 7 and 8 show sectional elevations at right angles to each other of
another modification.
The
The passage in this example is controlled by a piston valve 20- working in
a cylindrical chamber 32 that is formed with ports 32 and 32 communicating
respectively with those portions of the passage 1 which lead to the pump and
to the atmosphere.' The lower end of the chamber 32 opens into a chamber 33
which is in communication with the chamber d around the pump barrel through
the inclined pipe 34, the upper portion of the lower end of which extends into
said chamber as shown and forms a guide for causing water to enter the pipe.
Within the chamber 33 is a piston or valve 35 carried by the rod 36 of the piston
valve 20 and arranged immediately above the end of the pipe 34.
chamber 32 also communicates through a passage 37 with the pump barrel at
about the same level as the passage 1. The spindle 36 extends through adjust-
able guides 38 and its motion is limited by stops 39 which come in contact with
buffers carried by the guides. The spindle and attached parts are counter-
balanced by a weighted lever 40 connected to the spindle by à link 44, and the
movement of the spindle is retarded by an adjustable spring brake 45. The
action of the apparatus is as follows:-When the pump bucket displaces water
from the chamber d, some is driven up the pipe 34 so that it strikes the piston
or valve 35, and forces up the piston valve 20 which places the ports 32ª and 32b
in communication so that air can pass through the passage 1 to the barrel.
When the pressure in the barrel has been raised in this way or by the ascent
of the bucket the pressure in the passage 37 above the piston valve 20 becomes
greater than that in the chamber 33, and drives down the valve 20 which cuts
off communication between the barrel and the atmosphere before the next suc-
tion stroke commences. The apparatus is designed to open communication
between the barrel and the atmosphere after the pump bucket has commenced.
each discharge stroke and, as the movement of the valve is dependent upon the
water displaced from the chamber d by the pump bucket, such communication
cannot under any circumstances be opened until the bucket has practically
completed its suction stroke and opened the ports in the pump barrel:
If it be required to further delay the admission of air to the barrel, the
inlet to the passage 1 may be formed with a funnel-shaped receiver 40.to

page_text: which water is admitted during the working of the pump, which water must be
blown through the passage 1 into the barrel before air can enter, thus giving
the bucket time to again close the ports before the air is admitted.
Fig. 9 illustrates a further modification; in this case the passage 1 is con-
trolled by a valve 20 similar to a snifting valve but formed with a stirrup-
piece 20 which embraces a spring lever 20b fulcrummed at 20°. One end of
the lever is attached to a tension spring 20d which tends to open the valve, and
the other end rests upon a cam 20° carried by a shaft 20, that may conveniently
be driven by chain gear or otherwise from the crank shaft, if the pump be
crank-driven. The concentric portion of the cam forces the lever against an
adjustable screw 208 carried by the stirrup piece 20 so that the valve cannot
lift, and the cam shaft is so geared as to revolve at the same speed as the crank
shaft and the cam is so set that its recessed portion comes under the lever so
as to relieve the pressure on the screw 20% and to allow the valve to open only
whilst the pump bucket is making a discharge stroke. The lever and cam are
formed as shown so that the cam may be revolved in either direction and, if
desired, the lever may be provided with an antifriction roller.
In ordinary air pumps of the present day the form of the upper portion of
the barrel and bucket and the construction and position of the valves and seats
in relation thereto lead to shock or concussion and to waste of power. For in-
stance, the top of the bucket, and underside of the valve seat as ordinarily
constructed are flat, and the valves are so placed that when the bucket is rising
with a layer of water on it, the surface of the water strikes the underside of those
portions of the seat which are immediately round the rod and between the valve
openings without any definite tendency being mechanically given to it to travel
in any particular direction and without any immediate opportunity of release;
that is to say, in a vertical pump the water strikes an upward blow on these por-
tions of the valve seat, rebounds on to the bucket and, before it can escape,
must be started travelling towards one of the openings in the valve seat. It
then comes into collision with other water travelling from around the same
opening towards its centre and before finally escaping the water has its direction
again and again changed and there is a great confusion of currents. The result
is that in a pump of the ordinary kind it has been difficult to provide sufficient
outlet area, that there has been waste of power, concussions and knocks, and
that it has been impossible to drive such a pump at high speeds without render-
ing the working conditions unsatisfactory.
Now, according to my invention, the pump is so constructed and the dis-
charge valves are so placed and arranged that previous to or about the com-
mencement of the discharge, a portion of the water is set travelling by local
pressure in the pump and prior to pressure equal to this local pressure occur-
ring throughout the whole capacity of the pump, partly through space not occu-
pied by water, in nearly the direction in which it will ultimately have to flow
out of the pump, and the amount of water thus set in motion is gradually
increased and its speed gradually accelerated in the direction of the valves;
that is to say, the discharge valves are so placed and arranged that water set
in motion by the bucket and striking the upper parts of the pump will, in the
first instance, be deflected and set travelling more nearly in the direction in
which it will ultimately have to escape.
As in my construction I endeavour to make the water travel in a continuous
and more or less radial direction and from one common centre, viz. the centre
of the pump, outwards, it becomes easier to provide space for it to travel through
and concussions are reduced.
In the arrangement illustrated, the barrel cover 50, as will be seen from
Figs. 2 and 3, has a central portion 51 of truncated conical shape which is formed
with an aperture for the bucket rod and extends downwardly around said aper-
ture into the barrel the outlet openings 52, which are shown circular, extend
beyond the bore of the barrel, and the bars 53, which divide them up and form

page_text: the gratings that support the valves 54, are arranged radially to the axis of
the barrel or approximately so. The said bars are of decreasing width towards
their lower portions as shown in Fig. 3ª which is a section on the line C-C
Fig. and those intermediate portions of the cover between the apertures 52.
are likewise of decreasing width towards their lower portions as shown in Figs. 3b
and 3° which are sections on the line D D and E E Fig. 3. Where the open-
ings 52 extend beyond the bore of the barrel, it is flared or enlarged at its upper
part as shown at 55, Figs. 2 and 3. These flared or enlarged portions may, in
some cases, extend partly through the cover; or the enlargements may be
formed entirely in the cover. Around the bucket rod a recess 56 is formed in
the top of the bucket, the said recess corresponding in shape to the part 51 of
the cover, and the bucket is cut away at its circumference as shown at 57,
the underside of the cover between each pair of openings 52 being brought
down at a corresponding angle to that of the top of the bucket, thereby con-
siderably increasing the depth of the cover at this part, and enabling the under-
side of each such intermediate part to be more acutely chamfered or tapered.
With a pump thus constructed, water being lifted on the bucket adjacent
to the rod, and thus farthest from the valve openings, first comes in contact
with the part 51 of the cover and, owing to the angle at which it strikes the
part 51, it is at once set travelling in an outward or radial direction, and, whilst
so doing, will or may come in contact with other water travelling in a vertical
direction; the resultant of these two forces will or may be one having an out-
ward, upward radial direction such as to cause the water to flow towards and
through the several valve openings 52 with practically speaking no abrupt
change of direction, the water in passing between the bars 53 travelling in the
direction of their length instead of at an abrupt angle to their flat sides and
the section of the bars and the parts of the cover intermediate of the openings 52
being such as to gradually divert the water to the openings.
With this construction not only are sudden abrupt changes in the direction
and speed of the water avoided resistance being thereby reduced and the pump
rendered capable of being run satisfactorily at higher speeds, but if there is
any air under the cover, the water has a direct mechanical action tending to
drive it towards the outlet openings.
The part 57 of the bucket has also a natural tendency to set the water
travelling outwardly through the flared or enlarged parts 55. .
The openings 52 may be fitted with disc-like valves 54 as shown, or the
openings may be of curved or segmental form and provided with rubber or other
flap valves secured to their seats at their inner edges.
The cover or the central portion thereof may be concavely conical in form,
i.c. its under side, as seen in central vertical section, may have a curved con-
formation instead of being of truly conical form, the top of the bucket being
similarly formed.
In some cases, a cover formed as described with an inwardly extending part
may be arranged to lift bodily so as to itself serve as a discharge valve.
In pumps working in connection with surface condensers, or where the
amount of water dealt with is small, the depth of the water seal may be increased
by so constructing the cover that there is, at the end of the discharge stroke,
considerable clearance between the cover and the peripheral portion of the
bucket.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:-
'
1. A pump which in place of the ordinary snifting valve is provided with an
air inlet so controlled that the necessary air for cushioning purposes will only
be admitted to the barrel whilst the pump bucket is making a discharge stroke,
substantially as described.

page_text: 2. An air pump wherein the barrel cover is formed and arranged substan-
tially in the manner set forth so that water within the barrel is deflected or
set travelling gradually in a radial outward direction for the purpose specified.
3. An air pump wherein the top of the bucket and the barrel cover are so
formed that that portion of the water which is adjacent to the axis of the
barrel is set travelling towards, the outlet by.., local pressure, substantially as
described.
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4. An air pump wherein the top of the bucket and the barrel cover are so
formed with portions which extend into the barrel that that portion of the
water which is adjacent to the axis of the barrel and those portions of the water
which are below those parts of the cover, between the openings therethrough are
set travelling towards said openings by local pressure caused by the water being
driven against the inwardly extending portions of the cover, substantially, as
described.
.
5. An air pump wherein the barrel cover and the discharge openings there-
through are formed and arranged substantially in the manner set forth, the
cover extending downwardly into the barrel towards, its centre portion and being
of such a form that the water adjacent to the axis of the barrel first strikes said
downwardly extending portion of the cover at an angle, whereby the water is
deflected in an outward radial direction towards and through the discharge
openings, substantially as described.
6. In an air pump, a barrel cover having discharge openings divided up by
valve-supporting bars which are arranged radially to the axis of the barrel or
approximately so, substantially as described.
7. An air pump, the bucket and the barrel cover of which are constructed in
the manner described with reference to and shown in the accompanying draw-
ings.
1
8. The several improvements in air pumps hereinbefore described with refer-
ence to and shown in the accompanying drawings.
Dated this 2nd day of April 1900.