CROSS-FLOW FILTRATION WITH TURBULENCE AND BACK-FLUSHING
ACTION FOR USE WITH ONLINE CHEMICAL MONITORS
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The invention relates to filtration systems used with chemical monitoring systems
and, more particularly, to a filtration system configured to use turbulent and reverse flow to
remove contaminants from its filter element.
Description of Related Art
[0002] Chemical monitoring sensors often require a filtered supply of a coolant,
lubricant, fuel, water or other fluid to be monitored to maintain the proper operation and
maintenance of a multitude of industrial systems. Unfortunately, the filter elements utilized to
filter such fluids must be periodically replaced or cleansed to remove a clogging accumulation of
contaminants and foreign matter therefrom. The periodic removal and replacement of a clogged
filter element generally requires the shutting down of the industrial system during the
replacement procedure. The expensive, nonproductive downtime of the industrial system, the
replacement cost of the filter element and the expenses incurred to properly dispose of the soiled
filter element and the contents thereof in accordance with the ever-increasing degree of
governmental and environmental mandates, make cleansing systems for filter elements desirable.
[0003] It therefore would be desirable to have an improved filter element cleansing
system that reduces the operational cost of filtering and associated systems by extending the
usable life of the filter elements, by reducing the systems' downtime required to replace filter
elements and by reducing disposal costs.
SUMMARY OF THE INVENTION
[0004] In one aspect, the invention is directed to a filtration and monitoring system for
online monitoring of a parameter in a fluid system. The filtration and monitoring system
includes an online monitoring device and a filter block forming a chamber therein and having a
filter element. An inlet pipe provides fluid to the filter block chamber. The inlet pipe defines an
inlet axis and further has an inlet valve located therein configured to shut off the flow of the fluid
through the inlet pipe. An outlet pipe removes fluid from the filter block chamber, wherein the
outlet pipe defines an outlet axis. A filtered fluid conduit fluidically connects the filter block
with the monitoring device. The outlet axis of the outlet pipe is offset from the inlet axis of the
inlet pipe such that the fluid undergoes a change of direction while passing through the filter
block chamber thereby causing turbulent flow within the filter block chamber. The turbulent
flow produces a cleaning vortex flow within the filter block that sweeps off particles that
accumulate on the filter block chamber-side of the filter element to reduce the buildup of filter
cake on the filter element. Closing the inlet valve causes a relatively sharp stop to the flow of
fluid through the filter block resulting in a back-flushing flow of fluid from a pressure
accumulator located in the filtered fluid conduit to the filter block chamber through the filter
element. The back-flushing flow of fluid dislodges filter cake accumulated on the filter block
chamber-side of the filter element.
[0005] Another aspect of the invention is directed to a method of cleaning a filter element
in the online fluid monitoring system. The method includes delivering fluid to a chamber in a
filter block through an inlet pipe, the inlet pipe having an inlet valve therein configured to shut
off the flow of fluid through the inlet pipe. A portion of the fluid entering the chamber is filtered
with a filter element and then directed toward a monitoring device through a filtered fluid
conduit. The filtered fluid conduit has a pressure accumulator located therein. The method also
includes producing a turbulent cleaning flow within the chamber to sweep off particles that
accumulate on the chamber-side of the filter element to reduce the buildup of filter cake on the
filter element by removing fluid from the chamber through an outlet pipe with an outlet axis that
is offset from the inlet axis of the inlet pipe. The offsetting inlet and outlet axes cause the fluid
to undergo a change of direction while passing through the filter block chamber. Periodically,
the filter element is back-flushed by closing the inlet valve in the inlet pipe to stop to the flow of
fluid through the filter block. Closing the inlet valve results in a back-flushing flow of fluid from
the pressure accumulator to the filter block chamber through the filter element, which dislodges
filter cake accumulated on the chamber-side of the filter element.
[0006] The present invention and its advantages over the prior art will become apparent
upon reading the following detailed description and the appended claims with reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The above mentioned and other features of this invention will become more
apparent and the invention itself will be better understood by reference to the following
description of embodiments of the invention taken in conjunction with the accompanying
drawings, wherein:
[0008] FIG. 1 illustrates a schematic view of a online fluid monitoring system according
to an embodiment of the invention; and
[0009] FIG. 2 illustrates a partially transparent and exploded perspective view of the
online fluid monitoring system of FIG. 1.
[0010] Corresponding reference characters indicate corresponding parts throughout the
views of the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0011] The invention will now be described in the following detailed description with
reference to the drawings, wherein preferred embodiments are described in detail to enable
practice of the invention. Although the invention is described with reference to these specific
preferred embodiments, it will be understood that the invention is not limited to these preferred
embodiments. But to the contrary, the invention includes numerous alternatives, modifications,
and equivalents as will become apparent from consideration of the following detailed
description.
[0012] Referring to FIGS. 1 and 2, an online filtration system 10 used in conjunction
with a chemical monitoring device for a fluid system such as an industrial cooling water system,
boiler water system, waste water system, pulp paper water system, or other fluid system.
Generally, the filtration system 10 is used with an online monitoring device 12 capable of
monitoring a desired parameter of the fluid in the fluid system and a filter block 14 having a
filter element 16 enclosed therein for providing filtered fluid to the monitoring device 12. The
monitoring device 12 may be any known sensor capable of monitoring a parameter such as
salinity, phosphates, polymer, pH or other desired parameter. Alternately, the monitoring device
12 may be a fluid sampling mechanism through which a fluid sample may be drawn from the
fluid system for offline testing without departing from the scope of the invention.
[0013] An inlet pipe 20 having inlet axis I is provided for introducing a supply of fluid to
a filter block chamber 22 in the filter block 14. An outlet pipe 24 having outlet axis O removes
the fluid from the filter block 14. An inlet valve 26 is utilized to shut off or regulate the flow of
the fluid through the inlet pipe 20. Inlet valve 26 may be any type of manually or automatically
operated valve known to those skilled in the art.
[0014] A filtered fluid conduit 30 connects the filter block 14 with the monitoring device
12. Accordingly, the filter block chamber 22 in the filter block 14 is in fluid communication
with the monitoring device 12 and designed for cross flow filtration such that a small portion of
the fluid flow entering the filter block chamber 22 proceeds through the filter element 16 and is
directed to the monitoring device 12 through the filtered fluid conduit 30. The filter element 16
is preferably made of nylon or steel mesh having a pore size of between about 1 and 50 mih but
may be made of any other material known to those skilled in the art. As is known in the art, the
filter element 16 may be periodically removed from the filter block 14 for cleaning and or
replacement.
[0015] A pressure accumulator 32 is located in the filtered fluid conduit 30 between the
filter block 14 and the monitoring device 12. Desirably, the pressure accumulator 32 has an has
a volume of between about 25 percent and 100 percent of the volume of the filter block chamber
22, and more desirably between about 40 and about 60 percent of the volume of the filter block
chamber.
[0016] According to the invention, the outlet axis O of the outlet pipe 24 is offset from
the inlet axis I of the inlet pipe 20. The outlet axis O may be offset vertically, horizontally
and/or angularly or any combination thereof from the inlet axis I such that the fluid undergoes a
change of direction while passing through the filter block chamber 22, thereby causing turbulent
flow within the filter block chamber 22. Desirably, the offset between the outlet axis O and the
inlet axis I has a distance component D of at least between about 2 and 5 cm. The turbulent flow
produces a cleaning vortex flow within the filter block 14 that sweeps off particles P that
accumulate on the filter block chamber-side of the filter element 16 to reduce the buildup of a
filter cake. FIG. 1 illustrates turbulent flow lines within the filter block chamber 22 as indicated
by lines indicated by reference F.
[0017] While the turbulent flow within the filter block chamber 22 reduces filter cake
buildup, periodically it is desirable to further clean the filter element 16 without having to
remove it from the filter block 14. The disclosed filtration system 10 enables a back-flushing
flow of fluid through the filter element 16 to futher clean the filter element 16. Closing the inlet
valve 26 causes a relatively sharp stop to the flow of fluid through the filter block 14. The
accompanying pressure drop in the filter block chamber 22 caused by termination of fluid flow
from the inlet pipe 20 to the filter block chamber 22 results in the pressure in pressure
accumulator 32 being greater than the pressure inside the filter block chamber 22. This pressure
differential between the pressure accumulator 32 and the filter block chamber 22 results in a
back-flushing flow of fluid from the pressure accumulator 32 to the filter block chamber 22
through the filter element 16. The back-flushing flow dislodges any filter cake accumulated on
the filter block chamber-side of the filter element 16 and pushes the dislodged filter cake down
into the filter block chamber 22. When fluid flow is restored by opening the inlet valve 26, the
fluid stream through the filter block 14 pushes the remains of the filter cake out of the filter block
chamber 22 and through the outlet pipe 26. Fluid again passes through the filter element 16
toward the monitoring device 12 and replenishes the pressure accumulator 32 such that the
filtration system 10 returns to its normal filtering and monitoring operations.
[0018] While the disclosure has been illustrated and described in typical embodiments, it
is not intended to be limited to the details shown, since various modifications and substitutions
can be made without departing in any way from the spirit of the present disclosure. As such,
further modifications and equivalents of the disclosure herein disclosed may occur to persons
skilled in the art using no more than routine experimentation, and all such modifications and
equivalents are believed to be within the scope of the disclosure as defined by the following
claims.

[0019] What is claimed is:
CLAIMS
1. A filtration and monitoring system for online monitoring of a parameter in a fluid
system, the filtration and monitoring system comprising:
an online monitoring device configured to monitor a parameter of a fluid in the
fluid system;
a filter block forming a filter block chamber therein and comprising a filter
element;
an inlet pipe providing fluid to the a filter block chamber, said inlet pipe defining
an inlet axis and further having an inlet valve located therein configured to shut off the
flow of the fluid through said inlet pipe;
an outlet pipe removing fluid from the filter block chamber, said outlet pipe
defining an outlet axis; and
a filtered fluid conduit fluidically connecting the filter block with the monitoring
device, said filtered fluid conduit having a pressure accumulator located therein;
wherein the outlet axis of the outlet pipe is offset from the inlet axis of the inlet
pipe such that the fluid undergoes a change of direction while passing through the filter
block chamber thereby causing turbulent flow within the filter block chamber and closing
the inlet valve in the inlet pipe to stop to the flow of fluid through the filter block results
in a back-flushing flow of fluid from the pressure accumulator to the filter block chamber
through the filter element, thereby dislodging filter cake accumulated on the chamberside
of the filter element.
2. The filtration and monitoring system of claim 1 wherein the monitoring device is
a sensor capable of monitoring a parameter of the fluid.
3. The filtration and monitoring system of claim 1 wherein the monitoring device is
a fluid sampling mechanism through which a fluid sample is be drawn from the fluid system.
4. The filtration and monitoring system of claim 1 wherein the filter element is made
of nylon or steel mesh having a pore size of between about 1 and 50 mih.
5. The filtration and monitoring system of claim 1 wherein the pressure accumulator
has a volume between about 40 and about 60 percent of the volume of the filter block chamber.
6. The filtration and monitoring system of claim 1 wherein the outlet axis is offset
vertically from the inlet axis.
7. The filtration and monitoring system of claim 1 wherein the outlet axis is offset
horizontally from the inlet axis.
8. The filtration and monitoring system of claim 1 wherein the outlet axis is offset
angularly from the inlet axis.
9. The filtration and monitoring system of claim 1 wherein the offset between the
outlet axis and the inlet axis has a distance component of at least between about 2 and 5 cm.
10. The filtration and monitoring system of claim 1 wherein turbulent flow produces a
cleaning vortex flow within the filter block that sweeps off particles that accumulate on the filter
block chamber-side of the filter element to reduce the buildup of filter cake on the filter element.
11. The filtration and monitoring system of claim 1 wherein closing the inlet valve
causes a relatively sharp stop to the flow of fluid through the filter block resulting in the backflushing
flow of fluid from the pressure accumulator to the filter block chamber through the filter
element to dislodge filter cake accumulated on the filter block chamber-side of the filter element.
12. A method of cleaning a filter element in an online fluid monitoring system, the
method comprising:
delivering fluid to a chamber in a filter block through an inlet pipe, said inlet pipe
having an inlet valve therein configured to shut off the flow of fluid through said inlet
pipe;
filtering a portion of the fluid entering the chamber with a filter element;
directing the filtered fluid toward a monitoring device through a filtered fluid
conduit, said filtered fluid conduit having a pressure accumulator located therein;
producing a turbulent cleaning flow within the chamber to sweep off particles that
accumulate on the chamber-side of the filter element to reduce the buildup of filter cake
on the filter element by removing fluid from the chamber through an outlet pipe having
outlet axis that is offset from the inlet axis of the inlet pipe such that the fluid undergoes a
change of direction while passing through the filter block chamber; and
periodically back-flushing the filter element by closing the inlet valve in the inlet
pipe to stop to the flow of fluid through the filter block thereby resulting in a backflushing
flow of fluid from the pressure accumulator to the filter block chamber through
the filter element to dislodge filter cake accumulated on the chamber-side of the filter
element.
13. The method of claim 12 wherein the monitoring device comprises a sensor, the
method further comprising monitoring a parameter of the fluid with said sensor.
14. The method of claim 12 wherein the monitoring device comprises a fluid
sampling mechanism, the method further comprising drawing a fluid sample from the fluid
monitoring system.
15. The method of claim 12 wherein the turbulent flow is produced by vertically
offsetting the outlet axis from the inlet axis.
16. The method of claim 12 wherein the turbulent flow is produced by horizontally
offsetting the outlet axis from the inlet axis.
17. The method of claim 12 wherein the turbulent flow is produced by angularly
offsetting the outlet axis from the inlet axis.