Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~.,o36~
The invention relates to magnetic filters and, more particularly
to a double-flow magnetic filter.
From Germ~n Patents 1,277,488 and 1,816,859, electromagnetic
filters are known which are formed essentia]ly of a cylindrical vessel that
is charged with magnetizable balls. The cylindrical vessel is surrounded
by a coil which is energized with continuous or direct current during filter-
ing operation thereof and is demagnetized by alternating current before the
filter is rinsed. The water flows through the cylindrical vessel of the afore-
mentioned heretofore known electromagnetic filter from the bottom to the top
thereof. The flow velocity of the water is adjusted during the rinsing so
that the balls in the cylindrical vessel are whirled upwardly and the adherent
matter is removed from the balls.
Such electromagnetic filters have been installed heretofore, for
example, in steampower plants heated with fossile fuels and also in nuclear
power plants, in order to remove ferromagnetic impurities from the feedwater.
Depending upon the quantity of feedwater to be purified in such
a plant or system, either a large number of magnetic filters must be mutually
connected in parallel or electromagnetic filters of relatively large diameter
as compared to a relatively low structural height thereof must be built.
Corresponding to the dimensions of the filter, the coil for produc-
ing a magnetic field in a filter for relatively high flow-through rates must
be provided with a relatively large diameter for a relatively low coil height.
An electromagnetic filter therefore has a greater share of stray magnetic
flux for substantiaIly the same structural height and double the diameter.
ThiS causes irregularities or non-uniformities in the magnetic field and very
poor separation or deposition. Furthermore~ the quantity of rinsing medium
that must flow through the filter per unit time in order to permit the balls
to whirl upwardly, is essentially determined by the filter diameter so that
a considerable increase in the diameter of the filter requires correspon~ding
--1--
~036949
measure for assuring an adequatc r:insi.ng med.ium supply.
It is accordingly~nobject of the invention to provide an electro-
magnetic filter which permits greater flow-through rates for relatively
limited rinsing water demand without allow:ing non-uniformities or irregular-
ities in the magnetic field and high stray magnetic fields to occur due to
a disadvantageous dimension ratio of the coil diameter to the coil height.
With the foregoing and other objects in view, there is provided,
in accordance with the invention, electromagnetic filter for impure water
comprising an elongated substantially vertically disposed vessel traversible
by impure water that is to be purified~ a charge of magnetizable ball-like
pellets received in the vessel, electric coil means coaxially surrounding
the vessel, the coil means being electrically energizable to produce a
magnetic field, rinsing water supply means connected to the substantially
vertically disposed vessel at the lower end thereof, rinsing water discharge
means connected to the vessel at the upper end thereof, passage means having
a multiplicity of openings distributed over the cross section of the vessel
in a plane disposed transversely to the axis of the vessel at substantially
the middle of the charge of ball-like pellets, a pair of water connector
means, respectively, for supplying water to and discharging water from the
vessel~ means connecting the openings of the passage means to one of the
water connector means~ and respective lines extending from the ends of the
vessel to the other of the water connector means~ a shut-off valve being
cornected in one of the lines.
In accordance with another feature of the invention, the one line
. wherein the shut-off valve is connected extends from the upper end of the .
vessel, the shut-off valve being located in the one line between the other
water connector means and a location at which the rinsing water discharge
means branches from the one l;ne~ and including a closable connecting line
extending from the lower end of the vessel to the one water connector means.
10369'~9
In accordance with a further feature of the invention, the other
water connector means that is connected by the respective lines to both ends
of the vessel is connectible to a source of water to be supplied to the
vessel, the one of the lines extending from the upper end of the vessel,
the shut-off valve connected in the one of the lines being closable, when
switching the electromagnetic filter from filter operation to rinsing opera-
tion, so that the other of the lines, connecting with the lower end of the
vessel serves to conduct to the vessel rinsing medium suppliable through the
other water connector means.
In accordance with yet another feature of the invention~ the one
water connector means serves to conduct water to the openings in the passage
means located at substantially the middle of the charge of ball-like pellets,
and including a screen floor located above the lower end of the vessel, the
charge oP ball-like pellets being carried by the screen floor.
Other features which are considered as characteristic for the in-
vention are set forth in the appended claims.
Although the invention is illustrated and described herein as em-
bodied in a double flow magnetic filter, it is nevertheless not intended to be
l;mited to the details shown, since various modifications and structural
changes may be made therein without departing from the spirit of the inven-
tion and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however,
together with additional objects and advantages thereof will be best under-
stood from the following description of specific embodiments when read in
connection with the single figure of the drawing which is a schematic and
diagrammatic view of a double-flow magnetic filter according to the invention~
Referring now to the drawing, there is shown therein an embodiment
of the electromagnetic filter of the invention which is formed of a cyl;n-
drical vessel 1 wherein a charge of magnetizable balls or pellets 2 is
1036949
received on a scrcen floor 4. In the region wherein the charge of magnetiz-
able balls 2 is located, the vessel 1 is surrounded by an electromagnet coil
3. As seen in the figure, the charge of maKnetizable balls 2 extends up to
a level oonsiderably below the top of the vessel 1. Accordingly, a free space
is provided within the vessel 1 both above and below the charge of magnetizable
balls2. In the middle of the charge of balls 2, within the cylindrical
vessel 1, open passages 5 are formed over the cross section of the vessel 1
and are connected through tubes 6 and through an inlet valve 7 with a first
water connector 8. In the illustrated embodiment of the invention, the water
connector 8 serves for supplying impure water that is to be purified. The
cylindrical vessel 1 is connected at the ends 9 and 10 thereof through lines
11 and 12, respectively~ and an outlet valve 13 to a second water connector
14. A shut-off valve 15 is connected in the line 12 which branches from the
upper end 10 of the cylindrical vessel 1, as viewed in the figure. ~urther-
more, a rinsing medium discharge line 16 having a shut-off valve 1~ connected
therein extends from the upper end 10 of the cylindrical vessel 1. In addi-
tion~ a connecting line 18 having a shut-off valve 19 connected therein
extends from the lower end 9 of the cylindrical vessel 1 to the water connec-
tor 8. Although not specifically shown in the drawing, it is noted that the
electromagnet coil 3 is selectively connectable to a direct current source
or an alternating current source.
During normal operation of the electromagnetic filter of the inven-
tion, a continuous or direct current flows through the coil 3 and magnetizes
the balls 2 within the cylindrical vessel 1. Water travels from the water
connector 8 through the inlet valve ~ and the tubes 6 to the open passages or
openings 5 in the middle of the charge of the balls 2. Through the openings
5 in the branch tubes located in the middle horizontal plane of the ball
charge 2, part of the water flows to the upper end 10 and part to the lower
end 9 of the cylindrical vessel 1, as viewed in the figure. Magnetic impuri-
--4--
1~36949
ties contained in the water remain suspended on or adhering to the magnetized
balls of the charge 2 thereof, and thus purified water flows through the
lines 11 and 12 and through the outlet valve 13 to the water connector 14.
The considerably improved flow-through rate or output for such an
electromagnetic filter according to the invention results from the division
of the flow of water into two partial flows thereof, and the opportunity of
selecting a consideræbly larger diameter for the cylindrical vessel 1 than
conventionally, because the level of the charge of balls 2 lies markedly
above that for an electromagnetic filter which is traversed by the water in
only one direction.
To switch over the electromagnetic filter of the invention to
rinsing operation, the shut-off valve 15, the inlet valve 7 and the outlet
valve 13 are closed~ and the shut-off valves 17 and 19 are opened. The water
then flows through the connecting line 18 to the lower end 9 and through the
charge of balls 2 to the upper end 10 of the cylindrical vessel 1, and leaves
the latter through the rinsing medium discharge line 16. The rinsing water
flow velocity must be selected as before so that the balls of the charge 2
thereof are being whirled upwardly, the duration of the rinsing process
being not markedly increased, however, notwithstanding the greater level or
height of the charge of balls 2, while direct current is again applied to the
coil 3 during the rinsing of theeLectromagnetic filter of the invention and
thereby the remainder of the impurities, that has not yet been rinsed out,
again adheres to the balls 2. In this case, clean rinsing water is again
very rapidly received in the rinsing water discharge line 16, and the system
- can again be transferred to filter operation by switching over the valves.
With respect to flow-through quantity or rate, a considerably smaller
quantity of rinsing water is thereby required than for a filter having a
single flow-through direction. This fact permits branching off of the rins-
ing medium from the water connector 8 to the supply of the water when the
103694~9
water flow is not supposed to be interrupted. In this case, it is necessary
to connect or open the shut-off valve 15, as shown in the illustra~ dembodi-
ment, between the upper end 10 of the cylindrical vessel 1 and the water
connector 14. Furthermore~ in this case~ the outlet valve 13 is not closed
entirely so that a part of the water that flows through the connecting line 18
is employed for rinsing the electromagnetic filter of the invention, and
another part of the water is used for maintaining the water flow between the
water connectors 8 and 14.
If an interruption in the flow of water may occur i.e. there is no
objection to interrupted water flow, the connecting line 18 can be dispensed
with. It is also possible, then, to use the water connector 14 for supplying
the contaminated water and the water connector 8 for discharging the cleaned
water, without any by-pass line. A separate rinsing medium supply line is
then unnecessary since the line 11, which thenserves besides for feeding
the water, takes over this function of supplying rinsing medium when the shut-
off valve 15 is closed.
If one were, however, to use the water connector 8 for supplying the
water, and to dispose the screen floor 4 for the charge of magnetizable balls
2 closely above the lower end 9 of the cyl;ndrical vessel 1~ the result
thereof, for example, if there is a failure of the current supply to the
electromagnetic coil 3, would be that no water which is soiled due to the
dissolving impurities would enter the circulatory loop of the water~ because
the time period required for the water to flow through the space between the
end of the charge of balls 2 and the end of the cylindrical vessel would be
enough to interrupt the flow of water through the electromagnetic filter.
