Improvements in Apparatus for Filtering Water, especially applicable for Filtering Feed Water for Steam Generators.
Year: 1892

page_text: Date of Application, 12th Nov., 1892
Complete Specification Left, 12th Aug., 1893-Accepted, 16th Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Filtering Water, especially
applicable for Filtering Feed Water for Steam Generators.
I, DAVID ANDREW RANKINE, of 21 Lyra Road Waterloo, near Liverpool in
the County of Lancaster, Consulting Engineer, do hereby declare the nature of this
invention to be as follows:-
This invention has reference to apparatus for removing impurities from water by
filtration or straining through suitable media such as flannel or the like, and is
especially applicable for the filtration of feed water for steam generators, and I
will describe it with reference to such application.
According to my present invention, I construct such apparatus as follows
I provide a cylindrical casing having a lateral inlet branch for the feed water at
one end and a lateral outlet branch for the feed water at the other end; the
filtering medium is arranged within this casing in the form of a cylinder and is
supported on the outside of a perforated iron tube somewhat less in diameter and
length than the cylindrical casing, the said tube being supported in the casing as
follows;-
The inlet end of the casing has a cylindrical recess adapted to fit the external
diameter of the perforated tube and the end of the perforated tube which fits in the
recess is provided with an end washer which closes the end of the tube and lies in
the recess, being kept in position by the tube. The other end of the perforated
tube is provided with an annular ring cast or otherwise secured thereon; the
periphery of the annular ring is of conical configuration, the smaller diameter of
the conical portion being inside or nearest the centre of the perforated tube and
somewhat greater than the diameter of the latter. The annular ring has a central
boss to which it is connected by radial ribs. When the closed end of the perforated
tube lies in the recess at the inlet end of the casing, the annular ring is supported
by and makes joint with an internal flange or annular diaphragm extending from
the wall of the cylindrical casing near the outlet end. When the perforated tube
is in position it lies concentric with the cylindrical casing and is secured in position
by a bolt provided with a nut at one end which bears against the boss of the annular
ring, the other end of the bolt passing out through the end of the casing and being
screwed, so that the tube can be drawn into position by the rotation of a nut
provided with a handle. Means are provided for locking or preventing end motion
of the nut, and the bolt is provided with a collar bearing against the end washer, so
that the unscrewing of the bolt or nut ejects the perforated tube.
•
The inlet and outlet branches are controlled by stop valve boxes and being
arranged laterally, they can be conveniently connected by a third stop valve which
acts as a by-pass when it is desired to throw the filter out of operation.
The filtering medium consists of flannel or the like substance and I have found
that the material known as turkey or bath towelling answers admirably for the
purpose. The filtering medium is cut to suitable size and is arranged in one or
more convolutions round the outside of the perforated tube and each convolution is
secured in position by being buttoned to a number of button-head screws attached
to the perforated tube, and the roll is further secured in position by a spring clip
which encircles it.
Blow-off and relief valves are fitted to the casing and I find it advantageous to
fit a small-bore cock on the top of the casing near the outlet which I find allows a
small quantity of the air, which is found in the feed water, to escape as the water
is momentarily stilled in the filter.
The casing is also provided with a manhole door at the outlet end of sufficient

page_text: size to permit the perforated tube, with the filtering medium in position, to be easily
withdrawn; the filter is also fitted with safety valve and the necessary gauges.
The action is as follows;-The by-pass valve being closed and the inlet and
outlet valves open,. the feed water enters the annular space between the filtering
medium and the casing and as the outlet end of the perforated tube is jointed to
the internal flange by the annular ring and the inlet end fitted in the recess, the
feed water is forced to flow through the filtering medium and the perforations of
the tube and thence through the open end of the perforated tube to the outlet.
When the filtering medium becomes charged with the impurities from the water,
as indicated by the increased pressure, the by-pass valve is opened and the inlet
and outlet valves closed and the perforated tube and the filtering medium are
removed and a spare tube with new or cleansed filtering material is fitted in its
place.
Dated this Eleventh day of November 1892.
SLOAN & LLOYD BARNES,
Castle Chambers, 26, Castle Street, Liverpool, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Filtering Water, especially
applicable for Filtering Feed Water for Steam Generators.
I, DAVID ANDREW RANKINE, of 21 Lyra Road, Waterloo, near Liverpool in
the County of Lancaster, 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 apparatus for removing impurities from water by
filtration or straining through suitable media such as flannel or the like, and is
especially applicable for the filtration of feed water for steam generators, with
reference to which application I will describe it.
The present invention comprises certain improvements in the apparatus set forth
in the Specification of my prior British Letters Patent No. 8184 dated 30th April
1892, the objects being to render the apparatus more effective and to facilitate the
removal and renewal of the filtering medium.
In the accompanying drawings which serve to illustrate my invention, Fig. I
shows the apparatus in longitudinal section on the line A. B. of Figs. II and III;
Figs. I and II being transverse sections on the lines C. D. and E. F. respectively,
of Fig. I, the valves being omitted; Fig. IV shows the removable portion of the
apparatus with the filtering medium in position and Fig. V is an enlarged view
showing the method of securing the filtering medium on the perforated tube.
Throughout the drawings the same parts are indicated by the same reference
figures and in the case of sections the direction in which they are viewed is
indicated by the small arrows adjacent to the letters denoting the plane of section.
The filter chamber and the arrangement of the external valves resembles that
described in the prior Specification referred to and consists of a casing 1 having an
inlet 2 and an outlet 3, controlled respectively by the valves 4 and 5; the valves 4
and 5 are connected by the stop valve 6 which forms a by-pass valve and which is
normally closed so that the feed water to be filtered passes from the inlet 2 through
the casing to the outlet 3.
When it is desired to throw the filter out of operation the valves 4 and 5 are
closed and 6 is opened.
According to my present invention, the roll of filtering medium 7 is supported
on the outside of the perforated tube 8 which is supported concentrically within
the casing 1 by the annular diaphragm 9 located near the outlet end of the casing,
and by the cylindrical seating 10 at the opposite end; the internal configuration of
the annular diaphragm 9 is conical, and the end of the tube 8, which is supported
therein, is provided with an annular seating 11 adapted to make joint therewith,

page_text: the said seating having a central boss 12 carried by radial ribs. The opposite end
of the tube is fitted with an end piece or washer 13 which normally closes this end
of the tube.
The tube 8 is secured in position by the stud 14 which is secured to the boss 12
and the end piece 13 by the collar and nut shown, and which has a prolongation
passing through a hole in the end of the casing. This prolongation is screwed and
provided with a combined nut and hand wheel 15, capable of rotation but prevented
from moving laterally by the cotter 16, and which is adapted to draw the tube and
its attachments into position and to secure and also to eject them.
17 is a relief valve adapted to allow the water to pass without going through the
filtering medium should the latter offer too much resistance through becoming
foul.
This may be fitted at any part of the apparatus where it will offer the necessary
alternative passage for the water, but I find that the most convenient place is that
The valve
shown in Fig. I, controlling the valve seating 18 in the end washer 13.
is guided by the stud 14 and loaded by the spring 19 adjusted by the nut 20. The
central boss 21 of the end washer 13 is carried by the radial ribs 22, and the
passages 23 allow the water to have access to the valve.
The casing is provided with a removable door 24 secured in position after the
manner of a boiler man-hole door, the opening being large enough to allow the
tube 8 with its attachments to be withdrawn.
The roll of filtering medium is secured in position as shown in Figs. IV and V ;
a number of button-head screws 25 are screwed into the tube 8, and a suitable
length of the filtering medium is taken and a number of slits are cut along one
edge, said slits being passed over the heads of the screws; the medium is then
wound once round the tube and a second series of slits are cut which are also passed
over the screw heads, and so on for each successive convolution to the end of the
length, the whole being kept in position by means of the spring clips 26 carried on
the split tube 27 which slides on to the heads of the screws. The filtering medium
consists of flannel or the like material and I have found that the fabric known as
turkey or bath towelling answers admirably for the purpose.
Blow off or drain cocks are fitted at 28 and the apparatus is provided with the
necessary safety valve and gauges. also find it advantageous to fit a small bore
cock in the boss 29 at the top of the casing near the outlet end which I find allows
air, which is found in the feed water, to escape as the water is momentarily stilled
in the filter.
The action of the apparatus is as follows;-
The valves 4 and 5 being open and 6 closed, the feed water enters by the inlet 2
and, as the valve 17 is so loaded by the spring 19 that it remains closed until the
pressure reaches the maximum permissible in the casing, which is of course in excess
of the normal pressure against which the feed water has to flow, the feed water can
only flow, when the pressure is normal, through the filtering medium from outside
the tube 8 and thence to the outlet valve 5, any impurities being arrested by the
filtering medium; when the latter becomes so charged with the impurities that the
pressure exceeds the maximum permissible, the valve 17 opens and the feed water
flows from the inlet through the perforations 23, through the valve and through
the interior of the tube 8 to the outlet, the pressure in this way being relieved.
When the medium requires to be changed, the tube 8, its seating 11, end piece 13,
valve 17, spring 19, stud 14 and the filtering medium are withdrawn as a whole,
and a duplicate set on which new medium has been fixed, is inserted so that the
time required to change is a minimum.
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 ;-
1. In filters of the class herein set forth, the improved arrangement of the
filtering medium, which consists in supporting the said medium ou the outside of a

page_text: perforated tube, the said tube, with the medium in position, being adapted to fit in
seatings in the filter chamber and to be drawn into position or ejected as a whole
by means of a single stud;-substantially as described and illustrated.
2. In filters of the class herein described, the combination of the perforated
tube 8 closed at one end by an end washer, the annular seating 11 adapted to make
joint with a seating in the filter chamber, the filtering medium 7 supported on the
outside of the tube 8, the central stud 14 and the nut 15;-substantially as described
and illustrated.
3. The improved method of attaching the filtering medium 7 to the perforated
tube 8, substantially as described and illustrated
Dated this 11th day of August 1893.
SLOAN & LLOYD BARNES,
Castle Chambers, 26, Castle Street, Liverpool, Agents for the Applicant.