Improvements in Air Pumps for Condensers.
Year: 1898

page_text: Date of Application, 3rd Nov., 1898
Complete Specification Left, 3rd Aug., 1899-Accepted, 28th Oct., 1899
Improvements in Air Pumps for Condensers.
I, JOHN THOM, of 237, West George Street, Glasgow, in the County of Lanark,
Consulting Engineer, do hereby declare the nature of this invention to be as
follows:
This invention has reference to air pumps of the type used in connection with
condensers of steam engines, and other purposes of an equivalent or analogous
kind, and it relates to that species of this type of air pump, in which no valves
are employed in the bucket or piston or in the bottom of the pump, the entrance
of water and air into the pump cylinder or barrel taking place in front of or
above the bucket or piston when it is at the lower or outer end of its stroke.
The object and effect of the present invention is to improve pumps of this kind,
so that their action shall be better than those of this kind ordinarily used, that
is that their action shall be improved, and rendered more efficient, and at the
same time the pump, as regards general construction, shall remain as simple and
practical as those hitherto constructed.
The following description of air pump, and its action, comprises the improve-
ments under this invention:-
Within a vertical barrel or cylinder, there is employed a bucket or piston
having an imperforate diaphragm forming its roof; while below it is open,
forming a chamber closed above, and open from below, in which air is contained.
That is, the chamber in the bucket below, provides and forms an elastic cushion
of air; and by it, when the pump bucket comes to the bottom of its stroke, and
the lower edge of the cylindrical part forming its body enters the water in the
bottom of the barrel, it does so with a cushioning effect, and without knock
or hammering.
According to a further feature or characteristic of my air pump, the upper part
of the bucket is so formed as to hold water in it; that is, within its periphery,
the upper surface of the bucket lies below the level of the outer edge of the
bucket; as, for instance, it may be coned or curved downwards towards the centre,
thus providing a dished or cupped form of container for water. This vessel or
cavity on the top of the bucket is, according to one construction, and with advan-
tage, made of a capacity to hold about the amount of water it would normally
take at each stroke.
By this means, or construction, in case of a pump working slowly, or when
nearly stationary, when the bucket is at the bottom of the barrel or cylinder,
with the ports or openings above it exposed or uncovered, the water which has
flown into the pump barrel cannot run out again, as it can do with buckets not
so constructed. And furthermore, with a proper amount of openings to the
pump barrel above the bucket, any excess of water can flow back and the pump
will not become gorged.
With regard to the cover of the pump barrel, in which the delivery valves
are placed, this, according to one construction, is made on its underside to corre-
spond substantially in form with the shape of the top of the bucket, i.e. the
cavity or recess therein, and so that it will fill this cavity or recess.

page_text: In other cases, however, this plate or cover may be provided on its underside
with webs only, extending from a central boss or sleeve to the underside of the
plate or cover, at the edge.
In some cases, the first construction may be preferred; whilst in other cases
the latter construction may be suitable and sufficient.
The lower portion of the pump barrel or cylinder is made wider than the pump
barrel, and forms practically a chamber, and the inlet ways or ports for the
entrance of water or air from the condenser into the cylinder are formed by
recesses or passages open on the inside, and formed on the inside between webs,
extending from a point where the enlargement of the barrel commences, to below,
where the stroke of the bucket flange or body ends. The bucket, therefore, in
the lower part of its stroke works on the edges of these webs; and the flow of
water takes place through the ways then existing between the outer surface of
the bucket itself, and the inside of the enlarged part or bottom chamber of the
barrel. This provides a simple and inexpensive construction at the lower portion
of the pump barrel or cylinder.
A further feature connected with an air pump of the kind above described,
for engine condensers, consists in providing a conduit or pipe from the bottom
of the pump barrel-into which the water flows from the condenser to a point
in the upper part of the barrel; by which water flows during the down stroke
of the bucket, from the lower chamber of the barrel, to above the bucket; a non-
return valve being provided on the pipe or conduit to prevent a reflux of fluid.
By this, the water is carried in the down stroke, and fills the recess or cavity in
the top of the bucket; and at the same time partly reduces the vacuum above
the bucket, thereby diminishing the power necessary to drive it.
Dated this 2nd day of November 1898
CHEESBROUGH & ROYSTON,
Applicant's Patent Agents, 15, Water Street, Liverpool.
I, JOHN THOM, of 237, West George Street, Glasgow, in the County of Lanark,
Consulting Engineer, 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:-
-
This invention has reference to air pumps of the type used in connection with
condensers of steam engines, and other purposes of an equivalent or analogous
kind.
The object and effect of the present invention is to improve air pumps, so that
their action shall be better than those of this kind ordinarily used, that is that
their action shall be improved, and rendered more efficient, and at the same time
the pump, as regards general construction, shall remain as simple and practical
as those hitherto constructed.
The following description of air pump with the aid of the accompanying draw-
ing which is a sectional elevation-sets forth and illustrates the invention.
Referring to the drawings a is a bucket or piston of the pump; and e is the
pump barrel, i are the discharge valves in the upper cover j of the barrel e.
The piston a has a solid roof a¹ which is coned or curved towards the bucket
rod b, forming a cup or cavity which serves as a container for water; say of a
capacity to hold about the amount of water the bucket would normally take on
cach stroke whilst below, it is open, forming a chamber a², in which air will

page_text: be contained and carried, and constituting an air vessel, to the water in the bottom
or well e¹ of the barrel, when the piston enters it, at the end of its stroke.
c is the inlet to the bottom of the cylinder e from the condenser; and d are
ports or passages in the side of the cylinder a at the bottom part, which form
communications between the space below the piston i.e. the well, and above it,
when it is at the lower end of its stroke, and through these passages the normal
flow of air and also some water to the cylinder e takes place, due mainly to the
difference of pressure between the space below the piston or bucket, and above
it, at the moment of uncovering these passages or ports in its down stroke.
Then, according to this invention the conduit or pipe f, with a non-return
valve h in it, connects the bottom or well of the barrel e with the upper part of
the barrel above the piston; and through this conduit water and air flows from
the bottom or well of the barrel during the down stroke of the bucket, and flows
on to the top of the bucket, filling the cup or container therein; and at the same
time partly reducing the vacuum above the bucket, rendering the pressure on
each side of the piston or bucket nearly equal, and so diminishing the power
necessary to drive it in the down stroke. The conduit or pipe f enters the upper
end of the barrel e near the cover, and the valve h is also preferably placed
near this entrance.
The cover of the barrel, in which the discharge valves i are disposed and
work, as shown, is of a form, in its under side, corresponding with the surface
of the cup or water container on the upper side of the bucket; so that it will fill
more or less this cup or container at the end of the upper stroke of the bucket.
This plate or cover j, however, may be provided on its underside with webs only,
extending from the central boss or sleeve to the edge of the cover, or both bucket
and plate or cover j may be made flat.
With regard to the bottom portion e¹ of the barrel e, as constructed and shown,
it forms practically a chamber; and the inlet ways or ports d for the flow of air
or water, from the condenser into the cylinder, are formed by recesses or passages,
open on the inside between the webs d extending from a point where the enlarge-
ment of the barrel commences, to the bottom where the stroke of the bucket
flange or body ends. The bucket, therefore, in the lower part of its stroke, works
on the edges of these webs d', the flow of water taking place through the ways
or ports d, then existing between the outer surface of the bucket itself, and the
inside surface of the enlarged part e¹ of the barrel.
The invention is not restricted to the particular construction of the part shown,
but may be applied to different constructions or forms of pumps to which it is
suitable.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. An air pump for condensers comprising a barrel, and a bucket or piston
working therein, and having a passage or conduit, with a non-return valve
therein, connecting the well or bottom of the pump barrel, with the upper part
of the same for the purposes set forth.
2. An air pump for condensers comprising the vertical barrel e, with the
ports or passages d in its lower part; a bucket a; and a pipe f, with a non-
return valve h therein, connecting the bottom of the said barrel with the upper
part thereof; substantially as set forth.
Dated this 2nd day of August 1800
OHEESBROUGH & ROYSTON,
Applicant's Patent Agents, 15, Water Street, Liverpool.