FIELD OF THE INVENTION

This invention is related to backwashing or cleaning process of UF membrane, which is
particularly used in Domestic non electric water purifier. Backwashing is the process which is to
5 be conducted to clean the blockage of UF membrane by pressured water in backward direction of
filtration. This invention reduces the process and effort of UF membrane backwashing for user.

BACKGROUND
The gravity-based water purifier is another type of water purifiers that works on the
principle of gravity. It does not utilize electricity for purification. This basically means water
will be filtered by typical gravity process without applying any external force. Usually, the
gravity water purifier has two compartments, one for the raw water and other where pure water
gets stored. Water will be flowing from the upper section to the lower section naturally using the
15 force of gravity. For purification process usually, these water purifiers use activated carbon
filters and ultra filtration membrane to remove the impurities from water.
[003] Since, every water purifier comes with some advantages and disadvantages included
frequency and process of maintenance. The gravity-based water purifier gets choked during
20 filtration process due to deposition of impurities. Depending on feed-water quality, UF may
need frequent backwashing and cleaning.
[004] At present scenario UF membrane backwashing can be done with set of actives. Drain out
the water purifier, Remove the inner/upper tank from the purifier, remove the UF membrane
25 from connector attached with inner/upper tank. Inject the water with help of syringe into the
opening of UF membrane opposite to the direction of water flow. Impure water will flow out
from opposite opening. After cleaning UF membrane is to be fixed with connector attached with
inner/upper tank and then assemble water purifier in same manner. Water purifier becomes non
operative during backwash of UF membrane.
30
3
[005] US 3,698,554 discloses a filtering apparatus of down-flow type wherein liquid is
introduced into vessel (filter) through a water inlet for down ward passage through filter bed (of
granular material). Also the filter contains a layer of smooth-surfaced bodies supported by a wire
mesh screen and a perforated support structure for filter bed. The wire mesh screen extends
5 across the cross sectional area of vessel and is situated below the top surface of the filter bed.
The layer of smooth-surfaced bodies forms a restriction to the flow of fluid/liquid, that is, the
liquid must flow through the paths formed by the spaces between bodies. These spaces form
restrictive paths to the flow and in effect act as jets or nozzles. It also provides the up-flowing
backwash liquid with agitating gas wherein the quantity of backwash liquid required is low and
10 the rate of flow of this liquid can be kept low. This is done by employing a number of backwash
cycles with a predetermined amount of liquid passed up through bed and upto a predetermined
level above the bed. Here, the gas is used concurrently with the backwash liquid and/or in
sequence with it, wherein valve is opened so the liquid above the bed flows out. However, if
necessary, gas can be applied to the upper portion of vessel (filter) via valve, the pressure of gas
15 force the liquid up the outlet conduit.
[006] EP 3476454A1 discloses a filter with a backwashing unit which includes a filter cartridge
wherein the filter cartridge is internally provided with a filter element. The filter cartridge is
provided with water inlet and a drain outlet in an inlet region of the filter element and also
20 provided with a water outlet in an outlet region. Here, the backwashing channel is formed by the
water inlet, the port P1, the port B1, the outlet region of the filter element, the filter element, the
inlet region of the filter element, the port P3, the port A3 and the drain outlet when the port P1
communicates with the port B1, the port P2 does not communicates with the port A2 and the port
P3 communicates with the port A3. The switching between the filtering station and the
25 backwashing station is completed by simultaneously switching the two position three-way valve
F1, the second valve F2 and the third valve F3 instead of changing the water flow directions of
the water inlet and the water outlet.
[007] US 6283305B1 discloses a filter apparatus with backwashing mechanism comprising a
30 housing having an inflow and an outflow portion; a filter formed into a cylindrical shape from a
plurality of piled resilient filter chips, having a filtering gap for passage of the fluid to be filtered
4
between respective filter chips, and positioned between the inflow portion and the outflow
portion in the housing. It further comprises an actuator for compressing the filter to form a
filtering gap of predetermined size between the respective filtering chips wherein the
predetermined filtering gaps are formed by notches provided to the spring wire rod when
5 actuator presses the spring wire rod; a backwashing channel arranged for causing wash fluid to
flow through a flow path not including the outflow portion the filter in a direction reverse to the
fluid to be filtered; and a differential pressure sensor for detecting a difference differential
pressure between pressures on a primary side and a secondary side of the filter to detect clogging
of the filter.
10
[008] CN209024308 discloses an energy-saving backwash water purifier which utilizes solar
energy and controls the flushing inlet and outlet through an automatic control valve to carry out
cycle backwashing of the filter element. Here, the purifier includes two filters and a precision
filter wherein the filter element is one or a combination of a quartz sand filter element, an
15 activated carbon filter element and an ultra filtration membrane filter element. Each filter is
provided with an automatic control valve which is connected to the solar panel and uses solar
energy to provide the electric power of the automatic control valve.
[009] CN109289263 discloses a high-efficiency backwashing water purifier which includes a
20 casing, a venting pipe, a leg, a filtering chamber, a main water inlet pipe, a purified water inlet
pipe, a recoil sewage pipe, a water outlet pipe, and a backwash inlet water pipe, inlet, water
outlet, filter material, vent pipe control valve, purification water inlet pipe control valve, sewage
pipe control valve, backwash water inlet pipe control valve, water outlet pipe control valve and
water outlet hole, among which the filter room is located at inside the casing. The main water
25 inlet pipe is divided into two branches, one is a purified water inlet pipe, which is connected to
the upper end of the filter room, and the other is a backwash water inlet pipe, which is connected
to the lower end of the filter room. During backwashing the purifier, the control valve at the end
of the backwash sewage pipe is opened and the control valves on the purification inlet and outlet
pipes are closed. The backwashing water flows from the backwash inlet pipe and directly enters
30 material (back flushing force is increased) and is finally discharged from the recoil sewage pipe.
5
[010] CN107265570 discloses an automatic reverse washing water purifier comprising an
electromagnetic valve, a circulating pressure pump, RO reverse osmosis and a water storage
tank. Here, an electromagnetic valve is provided on a water production line at the RO reverse
osmosis water production end and RO reverse osmosis water inlet pipe is provided with a control
5 valve for water supply wherein water enters the RO reverse osmosis purification filter through
solenoid valve. The water storage tank is provided with a TDS sensor for detecting the quality of
the produced water of RO reverse osmosis. This TDS sensor can automatically determine the
TDS value of the water flowing into the water storage tank. If the TDS value in the water storage
tank id grater than a preset value, the TDS sensor will immediately trigger the RO reverse
10 osmosis and the electromagnetic valve on the water inlet pipe is closed and opens the sewage
outlet. At that time circulating pressure pump will be activated to work in reverse direction. The
circulating pressure pump will absorb the water produced in the water storage tank from the RO
back for cyclic flushing for 2 minutes and the waste liquid after flushing is discharged from the
sewage outlet of the solenoid valve on the RO membrane concentrated water line.
15
DISCLOSURE OF THE INVENTION
TECHNICAL PROBLEM
20 [011] In the existing gravity based water purifiers employing ultra filtration (UF) membrane,
there are two chambers- one above the another. The ultra filtration membrane is fitted through a
connector in the base of the upper chamber. The water filtered through the UF membrane
collects in the lower chamber. In case, UF membrane gets choked due to accumulation of
impurities, it has to be cleaned. For this purpose, the upper chamber of the water purifier has to
25 be dismantled. Then UF membrane has to be disconnected and cleaned from the reverse side, i.e.
water has to be injected from the outlet of the UF membrane and water with impurities is ejected
through the inlet of the UF membrane. After the cleaning operation is over, the UF membrane is
again fitted into the base of the upper chamber through the connector.
30 [012] Moreover, other filters employ a number of backwash cycles with a predetermined amount
of liquid passed up through granular bed and the gas pressure is also used concurrently with this
6
backwash liquid to force the liquid up the outlet conduit. This process takes extended period of
time and is not efficient in cleaning of granular bed entirely.
[013] Meanwhile, in some filters mechanisms are employed to detect the TDS quality of water
5 through the TDS sensor and upon ascertaining the TDS value of water being greater than the
present value then only pressure pump is activated to drain the water from the water storage tank.
In this the filter simply depends upon determining the TDS value of water stored in water storage
tank and does not disclose backwashing of the filter element due to clogging of filter element.
10 [014] In addition, we have seen that some purifiers work on power generated by solar energy and
also every filter in the water purifier is controlled by check valves for cleaning. Also some
purifier uses reverse osmosis (RO) technology to purify water which invariably requires
electricity to operate and also when RO is used, it reduces the TDS value of the water.
15 [015] The aim of the invention is to overcome the disadvantages of existing water purifier and
provide for a more efficient and energy saving water purifier.
SOLUTION TO PROBLEM
20 [016] The purpose of the embodiments of the present invention is to provide a backwashing
process of UF filter membrane which is used to solve the problem that the existing water
purification equipment does not have the function of reversely cleaning the filter element in more
efficient manner and without removing the upper tank and UF membrane for cleaning.
25 [017] In order to achieve the object of the present invention wherein the process of removing the
upper tank and the UF membrane for cleaning is eliminated, by introducing a one-way check
valve between the connector of upper tank and UF membrane, another one-way check valve
between the reject water passage and injection pump/syringe. Further, an additional passage to
drain reject/impure water with a T connector and one more passage connecting outlet of UF
30 membrane to the injecting pump/syringe through a three-way switching valve is introduced.
Also, the three-way switching valve is attached to the passage of purified water.
7
[018] Further, the object of the present invention is to provide a way of cleaning the ultra
filtration membrane which is prone to choking, by back flushing the filter membrane. This is
achieved by mechanical operation of the three-way switching valve and manual operation of
syringe for generating pressurized water for cleaning. Also, the filtration process is done on the
5 basis of gravitational force and no external energy / power is applied and usage of UF membrane
exerts no influence on TDS value of water. Besides, the periodical cleaning of ultra filtration
membrane enhances its life.
SUMMARY OF INVENTION
10
[019] The invention relates to providing a back washing/ back flushing mechanism of ultra
filtration membrane in the water purifier that gets clogged/ choked by repetitive use of the ultra
filtration membrane during water purification process.
15 [020] In an embodiment, the present invention features an improved filtering apparatus with back
flushing mechanism comprising a housing including an upper tank portion being provided with
inlet for the raw water to be filtered and a lower tank portion being provided with an outlet for
the filtered water wherein a filtering portion further includes an ultra filtration membrane, a
three-way switching valve, two one-way check valves, an injection pump, and a drain outlet
20 connected to the outlet passage of the ultra filtration membrane; wherein, the one-way check
valves are opened which allows the flow of water from the upper tank into the injection pump,
and three-way switching valve is manually moved in horizontal position and pressure is applied
externally from the injection pump which allows the pressurized water to flow from the port
connecting the injection pump and three-way switching valve to the port connecting the three25 way switching pump and ultra filtration membrane in reverse direction.
[021] The present invention further provides that said pressure is applied externally by the user
through the injection pump or by a syringe.
30 [022] The present invention further provides that said three-way switching valve is manually
turned by the user either in horizontal or vertical direction.
8
[023] The present invention further provides that said three-way switching valve is positioned in
vertical direction during the water purification process which allows the water to flow from the
ultra filtration membrane after filtering in to the lower tank portion.
5
[024] The present invention further provides that said three-way switching valve is positioned in
horizontal direction during the back flushing process which allows the pressurized water to flow
from the injection pump to the ultra filtration membrane.
10 [025] The present invention further provides that said ports (b, c) are open during the filtering
process and port (a) remains closed, and wherein the ports (a, b) are open during back flushing
process and port (c) remains closed.
[026] The present invention further provides that said one-way check valves only allow the water
15 to flow from the upper direction to lower direction and prevent water flow in the reverse
direction.
BRIEF DESCRIPTION OF DRAWINGS
20 [027] The above and other aspects, features, and advantages of certain embodiments of the
present disclosure will be more apparent from the following description taken in conjunction
with the accompanying drawings, in which:
Fig. 1 is a schematic structural diagram of online back washing of ultra filtration membrane in
25 water purifier and illustrating its various components.
DETAILED DESCRIPTION OF THE INVENTION
[028] The following description with reference to the accompanying drawings is provided to
30 assist in a comprehensive understanding of various embodiments of the present disclosure as
defined by the claims and their equivalents. It includes various specific details to assist in that
9
understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary
skill in the art will recognize that various changes and modifications of the various embodiments
described herein can be made without departing from the scope of the present disclosure.
5 [029] Referring to FIG. 1, the filter apparatus with back washing/ back flushing mechanism
generally includes a housing (1) divided into an upper tank portion (11) and a lower tank portion
(12) and a filtering portion comprising ultra filtration membrane (3) for filtering raw water, a
three-way switching valve (S4), two one-way check valves (C1, C2) and an injection
pump/syringe (6).
10
[030] More specifically, the housing (1) includes an upper tank portion (11) comprising an inlet
(2) for the inflow of the raw water to be filtered and a lower tank portion (12) for storing the
filtered water at the lower end of the housing (1) which further comprises an outlet for the flow
of purified water through a tap (5) as shown in FIG. 1.
15
[031] During the filtering process of the water, the raw water which is to be filtered enters
through the inlet (2) and is stored in the upper tank portion (11). The two one-way check valves
(C1, C2) allow the water to flow from the upper tank portion to the ultra filtration (UF)
membrane (3) for filtering. Water after getting filtered through the UF membrane (3) passes
20 through the port (b) to the three-way switching valve (S4) and enters the lower tank portion (12)
through the port (c) which is the storage tank for filtered water, while port (a) remains closed.
The three-way switching valve (S4) is manually positioned by the user in vertical direction so
that the ports (b, c) are open for the flow of filtered water and port (a) remains closed.
25 [032] Due to the repetitive use of UF membrane (3) for the water purification process, the UF
membrane (3) gets choked due to accumulated impurities. Therefore, embodiment of the present
invention involves back flushing the UF membrane to get rid of impurities accumulated on it and
to prevent choking, thus enhancing its life.
30 [033] When the back flushing process is required in order to clean the UF membrane (3), the
three-way switching valve (S4) is manually turned from the vertical to horizontal direction so
10
that the port (a) connected to the injection pump/syringe is opened and the port (c) connecting
the lower tank portion (12) containing the purified water is closed. When the UF membrane
needs to be cleaned, the three-way switching valve (S4) is positioned in the horizontal direction
and one-way check valves (C1, C2) allows the water to flow from the upper tank into the
5 injection pump/syringe (6). Here, the pressure is applied externally by the user onto the injection
pump which allows the pressurized water from the injection pump to flow through the port (a)
located between the injection pump and the three-way switching valve to port (b) located
between the three-way switching valve (S4) and UF membrane (3) in reverse direction, thereby
cleaning the ultra filtration membrane from any clogging and draining the waste water after
10 cleaning through the drain water pipe (7).
[034] During the back flushing process in the injection pump, the pressure is applied externally
by the user through the means of a syringe to inject water in the UF membrane for cleaning. The
pressure generated by a common syringe is enough for injecting the water into the UF
15 membrane.
[035] Following the description which has just been given in order to illustrate how the invention
can be produced advantageously, it should be noted that the invention is not limited to this
embodiment. It would be appreciated by those skilled in the art that changes may be made in
20 these embodiments without departing the scope of the present invention which is defined in
attached claims.

We claim:
1. A filtering apparatus with back flushing mechanism comprising:
a housing (1) including an upper tank portion (11) being provided with inlet (2) for the raw water
to be filtered and a lower tank portion (12) being provided with an outlet (5) for the filtered
water;
a filtering and back washing portion further includes
an ultra filtration membrane (3),
a three-way switching valve (S4),
two one-way check valves (C1, C2),
an injection pump (6), and
a drain outlet (7) connected to the outlet passage of the ultra filtration membrane (3);
wherein, the one-way check valves (C1, C2) remain open, which allows the flow of water from
the upper tank into the injection pump, and
three-way switching valve (S4) is manually moved in horizontal position and pressure is applied
externally from the injection pump which allows the pressurized water to flow from the port (a)
connecting the injection pump and three-way switching valve (S4) to the port (b) connecting the
three-way switching pump and ultra filtration membrane in reverse direction.
2. The filtering apparatus with back flushing mechanism as claimed in claim 1, wherein the
pressure is applied externally by the user through the injection pump (9) or by a syringe.
3. The filtering apparatus with back flushing mechanism as claimed in claim 1, wherein the
three-way switching valve (S4) is manually turned by the user either in horizontal or vertical
direction.
4. The filtering apparatus with back flushing mechanism as claimed in claim 3, wherein the
three-way switching valve (S4) is positioned in vertical direction during the water purification
process which allows the water to flow from the ultra filtration membrane (3) after filtering in to
the lower tank portion (12).
12
5. The filtering apparatus with back flushing mechanism as claimed in claim 3, wherein the
three-way switching valve (S4) is positioned in horizontal direction during the back flushing
process which allows the pressurized water to flow from the injection pump (6) to the ultra
filtration membrane (3).
6. The filtering apparatus with back flushing mechanism as claimed in claim 1, wherein the ports
(b, c) are open during the filtering process and port (a) remains closed, and
wherein the ports (a, b) are open during back flushing process and port (c) remains closed.
7. The filtering apparatus with back flushing mechanism as claimed in claim 1, wherein the oneway check valves (C1, C2) only allow the water to flow from the upper direction to lower
direction and prevent water flow in the reverse direction.