A New or Improved Filter Pump.
Year: 1891

page_text: Date of Application, 25th Apr., 1891
Complete Specification Left, 16th Jan., 1892-Accepted, 20th Feb., 1892
PROVISIONAL SPECIFICATION.
A New or Improved Filter Pump.
I, HERMANN NORDTMEYER, Headmaster of the Modern School of the Holy
Ghost, Gneisenauplatz II, Breslau, Germany, do hereby declare the nature of
this invention to be as follows :-
The filter pump which forms the subject of the present invention is especially
intended to be worked by hand and contains the following features, i.e. that directly
attached to the piston is a fitering substance, through which the water or other
liquid to be filtered must pass before being driven on by the piston; and in order
that the filtered liquid may not again come into contact with the sides of the cylinder,
the hollow piston rod serves to convey away the liquid which has been driven
through.
I will now proceed to describe two forms of filter pump. In both forms of
apparatus there is joined on to the cylinder or barrel immediately below it the
valve casing with a sieve or strainer and a perforated bottom for the suction ball or
other valve. To the piston the filtering substance is attached. The best form for
this is that of a hollow cylinder, closed underneath, of porous material, but it may
however be otherwise arranged. The piston rod is hollow and is provided with
delivery pipe shaped like a handle. In one form the piston rod works through a
In this
cap which closes the cylinder at the top, and is provided with an air-hole.
case the length of the cylinder must be equal to that of the stroke of the piston
and of the filtering cylinder together. This comparatively great length may at
times be inconvenient, as for instance during transport and in this case the other
form of apparatus is to be recommended, in which the piston is made in the form
of a tube and reaches to the lowest point of the filtering cylinder and thus leaves
a free space round the latter. At the lower end of this tube a packing ring is
inserted between two projecting flanges, so as to prevent leakage between the piston
and the sides of the cylinder. It is evident, without further elucidation, that this
When the
form of pump when shut up occupies a remarkably small space.
apparatus is placed in the liquid to be filtered, and the piston is raised, suction
takes place, and the air occupying the space above the piston in the form of pump
first described escapes through the air-hole in the cap of the cylinder. Then when
the piston is pressed down, the liquid previously sucked in, is forced to pass through
the filtering medium and to rise to the top of the piston rod tube. In order that the
movement of the piston may not be rendered too arduous the filtering-substance
must be of suitable diameter, i.e. it is best to make it in the form of a tube, so that
the filtering surface may be simultaneously increased. If the filtering substance be
very porous, it can be made shorter, or even in certain cases, when it is suitable,
may take the form of a simple plate. When suction takes place the filtering sub-
stance offers sufficient resistance to the return of the liquid, so that a valve in the
hollow piston rod can be wholly dispensed with.
It can be seen without further explanation that the filtered liquid which is forced
out through the piston rod tube does not again come in contact with the walls of
the cylinder which are wetted by the unfiltered liquid. By a suitable choice of
filtering material the user is therefore able with the arrangement described, to
provide himself without difficulty, on a journey, in the field and elsewhere, with
filtered drinking water perfectly free from bacteria. By drawing the piston out of
the cylinder the filtering material may be conveniently cleaned and can be easily
sterilised by boiling in a suitable vessel for a sufficient length of time. The filter
pump may also be used for filtering other liquids than water, such as wine, oil, and

page_text: the like, and may also be constructed of larger dimensions, in which case, a pump-
handle is necessary for working the piston.
Dated this 25th day of Anril 1891
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.
COMPLETE
SPECIFICATION.
A New or Improved Filter Pump.
I, HERMANN NORDTMEYER, Headmaster of the Modern School of the Holy
Ghost Gneisenauplatz II Breslau, Germany 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 :-
The filter pump which forms the subject of the present invention is especially
intended to be worked by hand and contains the following features i.e. that directly
attached to the piston is a filtering substance through which the water or other
liquid to be filtered must pass before being driven on by the piston, and in order
that the filtered liquid may not again come into contact with the sides of the
cylinder, the hollow piston rod serves to convey away the liquid which has been
driven through.
On the accompanying drawing the pump is represented in section in two different
forms. In both forms of apparatus there is joined on to the cylinder or barrel a imme-
diately below it, the valve casing with a sieve or strainer c and the perforated bottom d
for the suction ball or other valve i. To the piston the filtering substance h is
attached. The best form for this is that of a hollow cylinder closed underneath
of porous material, it may however be otherwise arranged. The piston rod g is
hollow and is provided with a delivery pipe k shaped like a handle. In the form
shewn in Figure 1, the piston rod g works through a cap which closes the cylinder a
at the top, and is provided with an air-hole . In this case the length of the
cylinder must be equal to that of the stroke of the piston and of the filtering
cylinder together. This comparatively great length may at times be inconvenient
as for instance during transport and in this case the other form of apparatus shewn
in Figure 2 is to be recommended, in which the piston f is made in the form of a
tube and reaches to the lowest point of the filtering-cylinder and this leaves a
free space round the latter. At the lower end of this tube a packing ring mis
inserted between two projecting flanges so as to prevent leakage between the piston
and the sides of the cylinder. It is evident, without further elucidation that this
form of pump when shut up occupies a remarkably small space. When the
apparatus is placed in the liquid to be filtered and the piston is raised suction
takes place, and the air occupying the space above the piston in the form of pump
shewn in Figure 1, escapes through the air hole in the cap of the cylinder. Then
when the piston is pressed down, the liquid previously sucked in, is forced to
pass through the filtering medium / and to rise to the top of the piston rod tube g.
In order that the movement of the piston may not be rendered too arduous, the
filtering substance / must be of suitable shape i.e. it is best to make it in the form
of a tube, so that the filtering surface may be simultaneously increased. If the
filtering substance be very porous, it can be made shorter, or even in certain cases
when it is suitable may take the form of a simple plate. When suction takes
place the filtering substance offers sufficient resistance to the return of the liquid,
so that a valve in the hollow piston rod can be wholly dispensed with.
It can be seen without further explanation that the filtered liquid which is forced
out through the piston rod tube 9 does not again come in contact with the walls a
of the cylinder which are wetted by the unfiltered liquid. By a suitable choice of
filtering material the user is therefore able with the arrangement described to
provide himself without difficulty on a journey in the field and elsewhere with
filtered drinking water perfectly free from bacteriæ. By drawing the piston out

page_text: of the cylinder, the filtering material may be conveniently cleaned and can be
easily sterilised by boiling in a suitable vessel for a sufficient length of time. The
filter-pump may also be used for filtering other liquids than water, such as wine,
oil and the like and may also be constructed of larger dimensions, in which case,
a pump handle is necessary for working the piston.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :--
First. A filter pump with hollow piston rod the piston of which is connected
with a filtering substance in such manner that the liquid is forced through it when
the pump is worked and is thence transmitted through the hollow piston rod, sub-
stantially as described.
Second. The constructions of filter pump as shown on the drawings.
1000
Dated this 10th day of January 1892.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.