U.S. patent application number 15/522960 was filed with the patent office on 2018-08-23 for cleaning method, control apparatus and connecting device.
This patent application is currently assigned to BOEHRINGER INGELHEIM PHARMA GMBH & CO. KG. The applicant listed for this patent is BOEHRINGER INGELHEIM PHARMA GMBH & CO. KG. Invention is credited to Rainer BAUER.
Application Number | 20180236386 15/522960 |
Document ID | / |
Family ID | 54325540 |
Filed Date | 2018-08-23 |
United States Patent
Application |
20180236386 |
Kind Code |
A1 |
BAUER; Rainer |
August 23, 2018 |
CLEANING METHOD, CONTROL APPARATUS AND CONNECTING DEVICE
Abstract
A cleaning method for sectional cleaning of a filter is
proposed, the filter having several filter sections, by means of
one cleaning process one of the filter sections at a time being
cleaned, the filter sections being cleaned within one cleaning
cycle in cleaning processes separated in time from one another, the
cleaning method having at least two cleaning cycles and both one
time interval between the cleaning processes within the respective
cleaning cycle and also one time interval between the end of one of
the cleaning cycles and the start of a following one of the
cleaning cycles being changed, and/or the filter having at least
three filter sections, the filter sections being cleaned in
cleaning processes separated by time intervals from one another and
the time intervals between successive cleaning processes being
changed. Moreover a connecting device for connecting a filter to a
cleaning device is proposed, the connecting device having one side
wall which borders an internal cross section which increases along
one longitudinal axis of the connecting device and has openings
laterally with assigned major axes.
Inventors: |
BAUER; Rainer; (Ingelheim am
Rhein, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BOEHRINGER INGELHEIM PHARMA GMBH & CO. KG |
Ingelheim am Rhein |
|
DE |
|
|
Assignee: |
BOEHRINGER INGELHEIM PHARMA GMBH
& CO. KG
Ingelheim am Rhein
DE
|
Family ID: |
54325540 |
Appl. No.: |
15/522960 |
Filed: |
October 14, 2015 |
PCT Filed: |
October 14, 2015 |
PCT NO: |
PCT/EP2015/073793 |
371 Date: |
October 24, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01D 46/04 20130101;
B01D 46/4272 20130101; B01D 46/0065 20130101; B01D 46/0019
20130101; B01D 46/0068 20130101; B01D 46/10 20130101; B01D 46/002
20130101 |
International
Class: |
B01D 46/00 20060101
B01D046/00; B01D 46/10 20060101 B01D046/10; B01D 46/04 20060101
B01D046/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 28, 2014 |
DE |
20 2014 008 509.9 |
Oct 28, 2014 |
EP |
14003655.9 |
Claims
1-60. (canceled)
61. A cleaning method for sectional cleaning of a filter which has
a plurality of filter sections by means of a cleaning process in
which the filter sections are cleaned one at a time, the cleaning
method comprising at least one of the following steps: cleaning the
filter sections within at least two cleaning cycles in which
cleaning processes for each filter section are separated from one
another by a time interval, both the time interval between the
cleaning processes within a respective one of the cleaning cycles
and also a time interval between the end of one of the cleaning
cycles and starting of a following one of the cleaning cycles being
changed; and for a filter having at least three filter sections
cleaning the filter sections cleaned in cleaning processes
separated from one another by a time interval, the time interval
between successive cleaning processes being changed.
62. The cleaning method as claimed in claim 61, wherein each of
said filter sections is a filter cartridge, and wherein the method
comprises cleaning said filter cartridges from one another in
cleaning processes separated by said time interval.
63. The cleaning method as claimed in claim 61, wherein a first
time interval between the successive cleaning processes of a first
and a second filter section and a second time interval between
successive cleaning processes of the second and a third filter
section are each changed.
64. The cleaning method as claimed in claim 61, wherein the time
intervals are changed by means of a feedback control.
65. The cleaning method as claimed in claim 64, wherein the
feedback control adjusts a differential pressure between a filter
inlet and a filter outlet of the filter or a differential pressure
between a filter inlet and a filter outlet of the filter is used as
a controlled variable in the feedback control, wherein a target
differential pressure is used as a reference variable in the
feedback control, and wherein a difference between a target
differential pressure and the differential pressure is used as a
system deviation in the feedback control.
66. The cleaning method as claimed in claim 64, wherein the
feedback control uses a proportional-integral-derivative (PID)
controller as a controller.
67. The cleaning method as claimed in claim 64, wherein triggering
of a cleaning process of one of the filter sections is used as a
manipulated variable in the feedback control.
68. The cleaning method as claimed in claim 65, wherein the
differential pressure or system deviation is filtered with a
control filter such that peaks or fluctuations of the differential
pressure caused by one or more cleaning processes are essentially
suppressed.
69. The cleaning method as claimed in claim 61, wherein the time
intervals between the cleaning processes within one cleaning cycle
are constant.
70. The cleaning method as claimed in claim 61, wherein the time
intervals between the cleaning processes or the time intervals
between the end of one of the cleaning cycles and the start of a
following one of the cleaning cycles become smaller with at least
one of increasing clogging, fouling of the filter, and time.
71. The cleaning method as claimed in claim 61, wherein the time
intervals between the cleaning processes or the time intervals
between the end of one of the cleaning cycles and the start of a
following one of the cleaning cycles are limited with a maximum
value or a minimum value.
72. The cleaning method as claimed in claim 61, wherein a pressure
pulse is used for sectional cleaning of the filter or of one filter
section.
73. A system comprising: a connecting device for the connection of
a filter to a cleaning device, the connecting device forming an
adapter to fluidically connect the filter to the cleaning device,
the connecting device having a side wall which delimits an internal
cross section which increases along a longitudinal axis of the
connecting device, and has openings laterally with assigned major
axes, the connecting device having one or more of the following
features: the major axes of the openings run obliquely relative to
the side wall and run from outside to inside in a direction of an
internal cross section which is greater than an internal cross
section into which the respective opening discharges; the openings
are oriented at at least one plane which is aligned orthogonally to
the longitudinal axis; and the side wall has a first section with
openings, and a second section free of openings in a region of the
greatest internal cross section.
74. The system as claimed in claim 73, wherein the major axes of
the openings intersect the longitudinal axis at a second angle, the
second angle being less than 90.degree..
75. The system as claimed in claim 73, wherein a diameter or a
width of a smallest internal cross section is at least one of
greater than 30 mm, and more than 20% of a diameter or a width of
the greatest internal cross section.
76. The system as claimed in claim 73, wherein the openings are
oriented in one or more planes, the planes each being defined by at
least three openings.
77. The system as claimed in claim 73, wherein the number of
openings per plane increases with increasing internal cross
section.
78. The system as claimed in claim 73, wherein the openings have a
diameter or a width which is at least one of: more than 2% of the
diameter or width of the greatest internal cross section, and less
than 20% of the diameter or of the width of the greatest internal
cross section, at least 5 mm, and at most 40 mm.
79. The system as claimed in claim 73, wherein the connecting
device has a connecting apparatus for connection to the cleaning
device and a connecting apparatus for connection to the filter.
80. The system as claimed in claim 73, further comprising a
cleaning device for cleaning of the filter, wherein the connecting
device forms an adapter for fluidically connecting the filter to
the cleaning device, wherein the cleaning device is configured to
clean the filter by means of a gas flowing in a direction of
increasing internal cross section of the connecting device.
81. The system as claimed in claim 80, further comprising a filter,
wherein the connecting device has a side wall which delimits the
internal cross section, which increases along one longitudinal
axis, and has openings laterally.
82. The system as claimed in claim 81, wherein the system is
configured to direct a gas which is cleaned by means of the filter
from the inside to the outside of the filter or filter section
through the openings.
83. An installation for coating processes, comprising: an
installation housing, a filter and a cleaning device for cleaning
of the filter, wherein the installation housing has a storage
apparatus in an interior space of the housing and which is
configured to supply the cleaning device with a first medium which
is gas; wherein the interior space of the installation housing has
at least one valve for triggering a cleaning process; and wherein
the interior space of the installation housing has a connecting
device which connects the filter to the cleaning device, the
connecting device having a side wall delimiting an internal cross
section which increases along a longitudinal axis, and has openings
laterally.
84. The installation as claimed in claim 83, wherein the interior
space of the installation housing forms an explosive zone, at least
in part.
85. The installation as claimed in claim 84, wherein the storage
apparatus is a gas reservoir forming a gas line network, wherein
the storage apparatus is a ring or ring-shaped and supplies several
filter sections of the filter with gas for cleaning, and wherein at
least one valve is located in the storage apparatus.
86. The installation as claimed in claim 84, wherein the
installation has a control apparatus for controlling the valve with
a time for opening or closing of the valve that is more than 20 ms
and less than 200 ms.
87. The installation as claimed in claim 84, wherein each filter
section is a filter cartridge, and each filter cartridge is
connected to the storage apparatus by one of said valves.
Description
[0001] This invention relates to a cleaning method for cleaning of
a filter in sections according to the preamble of claim 1, a
control apparatus for executing a cleaning method according to the
preamble of claim 14, a connecting device for connecting a filter
to a cleaning device according to the preamble of claim 15, a
cleaning device for cleaning of a filter according to the preamble
of claim 34, a filter system with a filter and a cleaning device
for cleaning the filter according to the preamble of claim 42, and
an installation, in particular for coating processes, with an
installation housing, a filter and a cleaning device for cleaning
of the filter according to the preamble of claim 46.
[0002] The term "cleaning method" in this invention is defined as
all methods, procedures and processes by means of which the
cleaning of a filter, of a filter system and/or of an installation
before, during and/or after filtration by means of the filter is
planned, analyzed, implemented, coordinated and/or adjusted or
controlled.
[0003] Cleaning methods are necessary in many installations and/or
filter systems in order to clean fouled or clogged filters. In
current cleaning methods for sectional cleaning of a filter which
has several filter sections, in particular filter cartridges, the
filter sections are cleaned in cleaning processes separated from
one another by fixed or constant time intervals. In doing so it can
happen that the filter or one of the filter sections is being
cleaned, although this is not yet necessary at the time of
cleaning. In particular in such a cleaning method a filter cake
which forms on the filter can be cleaned off or removed too early
or too late by means of the cleaning. Accordingly additional and
avoidable costs are also associated with such a cleaning
method.
[0004] The term "connecting device" in this invention is preferably
a structural apparatus, in particular for filter systems, cleaning
devices and/or installations, for example as an adapter or
intermediate piece which is preferably made to fluidically connect
a filter to a cleaning device. In particular a connecting device is
made to direct a medium, in particular a fluid of the cleaning
device, to the filter which is preferably connected to the cleaning
device.
[0005] The term "cleaning device" in this invention is defined
preferably as a device which is made to clean an assigned filter,
preferably pneumatically or by means of compressed air, preferably
particles in or on the filter and/or a filter cake of the filter
which has formed or is forming on the filter being removed
partially or completely from the filter.
[0006] Especially preferably cleaning devices generate a pressure
pulse, in particular at least essentially against that flow
direction which prevails in the filter in filtration by means of
the filter. Cleaning devices are used both during continuing
operation of the filter or of the filter system (online operating
mode) and also when the operation of the filter or of the filter
system is being interrupted (offline operating mode).
[0007] The term "filter system" in this invention is defined
preferably as a system which has at least one filter and at least
one cleaning device for cleaning of the filter. The filter of a
filter system is preferably made to remove and filter
solids/particles of a fluid from the fluid within the scope of
filtration. In particular the separation of the particles of the
fluid to be cleaned takes place by a filter medium of the filter,
within the filter medium and/or by means of a filter cake which has
formed or is forming on the filter medium. According to this
definition filters are especially surface filters, such as filter
cartridges or filter hoses which are made in particular to separate
particles of a gas or raw gas by means of cake filtration and/or
filter-medium filtration.
[0008] The term "installation" in this invention is defined in
particular as industrial installations and/or process-engineering
installations. In this invention they are preferably coating
installations for coating of a product with a layer. In particular
installations according to this definition are made to coat
pharmaceutical products such as pellets. Preferably the coating
takes place by means of fluidized bed processes, in particular the
product to be coated being fluidized as a fluidized bed. Preferably
installations according to this definition have a filter system
with a filter and a cleaning device for cleaning of the filter, in
particular to separate particles such as dust from a raw gas during
the coating process and/or to supply them again to the coating
process.
[0009] Cleaning devices are necessary in many methods to clean
fouled or clogged filters. Current cleaning devices, filter systems
and/or installations have cleaning devices which are spaced
3-dimensionally apart from assigned filters such that during
filtration the cleaned medium or the clean gas can escape from the
filter, in particular from the filter outlet of the filter. DE 298
23 965 U1 and EP 1 507 579 B1 disclose compressed air pulse
injector systems which for cleaning and regeneration of individual
filter cartridges by means of compressed air are located and spaced
above the filter and for cleaning purposes blow compressed air
first into the space surrounding the compressed air pulse injector
systems and then into the respective filter cartridge. Based on the
distance between the outlet of the cleaning device and the filter
cartridge to be cleaned at the time, high flow losses arise which
can lead to the respective filter cartridges, in particular in the
neck region, not being completely cleaned and/or having to be
cleaned very often or repeatedly.
[0010] The object of this invention is to devise a cleaning method
for cleaning of a filter as well as a control apparatus for
executing a cleaning method for cleaning of a filter which enables
or supports improved, reliable, efficient and/or economical
cleaning of the filter and/or filtration by means of the filter
and/or the number of cleaning processes is minimized. Furthermore
the object of this invention is to devise a connecting device in
particular for connecting a filter to a cleaning device, a cleaning
device, a filter system and an installation, as a result of which a
compact construction and/or reliable, efficient, economical,
low-maintenance and low-loss cleaning of the filter or of a filter
section of the filter is enabled or supported.
[0011] This object is achieved by a cleaning method as claimed in
claim 1, a control apparatus as claimed in claim 14, a connecting
device as claimed in claim 15, a cleaning device as claimed in
claim 34, a filter system as claimed in claim 42, or an
installation as claimed in claim 46. Advantageous developments are
the subject of the dependent claims.
[0012] One aspect of this invention lies in that the filter
sections are cleaned within one cleaning cycle in cleaning
processes which are separated in time from one another and the
cleaning method has at least two cleaning cycles, both one time
interval between the cleaning processes within the respective
cleaning cycle and also one time interval between the end of one of
the cleaning cycles and the start of a following one of the
cleaning cycles being changed. In this way it is possible to reduce
the number of necessary cleaning processes overall, to leave a
filter cake as long as possible on the filter sections and or/to
optimize or change the time or the time interval between the
cleaning processes within the respective cleaning cycle as well as
the time interval between the end of one of the cleaning cycles and
the start of a following one of the cleaning cycles such that the
cleaning method cleans the filter altogether more reliably,
efficiently and/or economically.
[0013] According to another independently attainable aspect of this
invention the filter has at least three filter sections, the filter
sections being cleaned in cleaning processes separated by time
intervals from one another and the time intervals between
successive cleaning processes being changed. The already explained
advantages can be achieved in this way.
[0014] Preferably the time intervals between the cleaning processes
within the respective cleaning cycle and also the time intervals
between the end of one of the cleaning cycles and the start of a
following one of the cleaning cycles is changed by means of
feedback control. This enables preferably complete automation of
the suggested cleaning method, in particular reliable, efficient
and/or economical cleaning of the filter and/or filtration by means
of the filter being achieved.
[0015] Especially preferably the feedback control adjusts a
differential pressure between one filter inlet and one filter
outlet of the filter and/or a differential pressure between one
filter inlet and one filter outlet is used as the controlled
variable in the feedback control. This advantageously makes it
possible to change the time intervals depending on the differential
pressure by means of the feedback control.
[0016] In one especially preferred version of the suggested
cleaning method the differential pressure or the system deviation
is filtered with a control filter, preferably with a lowpass
characteristic and/or such that peaks and/or fluctuations of the
differential pressure caused by one or more cleaning process are at
least essentially suppressed or filtered. This ensures that the
cleaning method is quiet and/or stable.
[0017] Especially preferably the time intervals between the
cleaning processes within one cleaning cycle are constant or are
kept at a constant value. In this way the complexity of the
cleaning method is reduced and the number of possible fault sources
is minimized.
[0018] One suggested control apparatus is made to execute the
suggested cleaning method, preferably the control apparatus being
made to determine using at least one pressure sensor a differential
pressure between a filter inlet and a filter outlet of the filter,
and/or to trigger a valve to initiate a cleaning process. In this
way the already explained advantages can likewise be achieved.
[0019] Another also independently attainable aspect of this
invention lies in that a connecting device has one side wall which
borders an internal cross section which increases along one
longitudinal axis of the connecting device and has openings
laterally with assigned major axes, the major axes of the openings
running obliquely to the side wall and pointing from outside to
inside in the direction of one internal cross section which is
greater than an internal cross section into which the respective
opening discharges. In this way the suggested connecting device
enables a direct connection of the filter to the cleaning device
and/or a support of the cleaning device both during the cleaning
and also during the filtration.
[0020] In particular the medium with which the filter is being
cleaned, during and/or for cleaning travels from the cleaning
device via the connecting device directly to the filter, while the
medium cleaned by means of the filter or the clean gas can escape
from the filter through the openings of the connecting devices from
the inside to the outside. Consequently it is not necessary to
replace, change or three-dimensionally move the connecting device
for the respective operation of the filter.
[0021] The openings which run obliquely to the side wall preferably
reduce flow losses both during cleaning and also during
filtration.
[0022] The manner of construction of the connecting device
preferably and advantageously increases the mass flow and/or the
pressure of the medium with which the filter is being cleaned
and/or reduces the risk of possible flow detachment on the side
wall of the connecting device during cleaning.
[0023] According to another also independently attainable aspect of
this invention, the openings of the connecting device are oriented
at one or more planes which is or are aligned orthogonally to the
longitudinal axis of the connecting device. This ensures economical
production of the connecting device and enables the side wall of
the connecting device to be provided with as many openings as
possible, in particular without the connecting device losing
stability.
[0024] According to another also independently attainable aspect of
this invention the side wall has a section free of openings in the
region of the greatest internal cross section. In this way the flow
losses during cleaning are reduced and/or a pressure rise by means
of the connecting device is enabled during cleaning, in particular
without the medium with which the filter is being cleaned flowing
from the inside to the outside through the openings of the
connecting devices and thus not contributing to the cleaning of the
filter.
[0025] A suggested cleaning device for cleaning of a filter
preferably has the suggested connecting device in order to connect
the filter to the cleaning device. In this way the already
explained advantages can be achieved.
[0026] A suggested filter system with a filter and a cleaning
device for cleaning of the filter preferably has the suggested
connecting device for connection of the filter to the cleaning
device. In this way the already explained advantages can likewise
be achieved.
[0027] A suggested installation, in particular for coating
processes, with an installation housing, a filter and a cleaning
device for cleaning of the filter preferably has the suggested
connecting device. In this way the already explained advantages can
likewise be achieved.
[0028] According to another also independently attainable aspect of
this invention, the installation has an installation housing which
in the interior has a storage apparatus which is made to supply the
cleaning device with a medium with which the filter is being
cleaned, in particular compressed air. This reduces the distance
between the cleaning device and a storage apparatus which is
located outside the installation housing. Along with this, the flow
losses of the cleaning device are reduced and/or the existing
construction space in the installation housing is efficiently used
or a compact installation is enabled.
[0029] According to another also independently attainable aspect of
this invention the installation housing internally has a valve for
initiating a cleaning process. This likewise enables optimized use
of the construction space in the installation housing and prompt
control or adjustment of the cleaning. The valve preferably
connects the storage apparatus to the connecting device, in
particular fluidically and/or on one end facing away from the
filter or end with reduced internal cross section of the connecting
device.
[0030] The aforementioned aspects and other aspects and features
arising from the claims and following description can be
implemented independently of one another and in any
combination.
[0031] Other advantages, features, properties and aspects of this
invention follow from the claims and the following description of
preferred embodiments using the drawings.
[0032] FIG. 1 shows a schematic section of a suggested installation
with a suggested filter system, a suggested connecting device and a
suggested cleaning device;
[0033] FIG. 2 shows a perspective view of a suggested connecting
device;
[0034] FIG. 3 shows a schematic section of a suggested filter
system with the connecting device, a valve in the closed state and
a filter shown in sections;
[0035] FIG. 4 shows a schematic section of the filter system
according to FIG. 3 with the valve in the opened state;
[0036] FIG. 5 shows a schematic plan view of the suggested filter
system as well as a suggested cleaning device with a storage
apparatus and several control apparatus;
[0037] FIG. 6 shows a schematic side view of a suggested
installation with a suggested filter system, a first filter section
of the filter being cleaned;
[0038] FIG. 7 shows a schematic side view of the installation
according to FIG. 6, a second filter section of the filter being
cleaned;
[0039] FIG. 8 shows a schematic block diagram of a feedback control
underlying a suggested cleaning method;
[0040] FIG. 9 shows a schematic of the pressure as a function of
time in the suggested cleaning method according to a first version
of the method; and
[0041] FIG. 10 shows a schematic of the pressure as a function of
time in the suggested cleaning method according to a second version
of the method.
[0042] In the only schematic figures which are partially not to
scale, the same reference numbers are used for the same or similar
parts, corresponding or comparable properties and advantages being
attainable even if a repeated description is omitted.
[0043] The installation 1 shown in FIG. 1 is preferably made to
carry out coating processes. In particular the installation 1 is a
fluidized bed coating installation for the production of pellets
(not shown) or for pelletizing within the scope of preferably
pharmaceutical production.
[0044] The installation 1 preferably has an installation housing 2
with a housing inlet 3 and a housing outlet 4.
[0045] Preferably the installation housing 2 is made as a reactor.
Especially preferably the pelletizing or coating/production of the
pellets takes place within the installation housing 2.
[0046] Preferably the installation housing 2 is or can be divided
into an inlet air region 5, spray region 6, filter region 7 and
dome region/clean gas region 8.
[0047] The housing inlet 3 is preferably fluidically connected to
an inlet air system (not shown) which is made to supply the
installation 1 or the installation housing 2, in particular the
inlet air region 5, with inlet air 9, in particular the inlet air 9
being conditioned by means of the inlet air system for the
coating.
[0048] Preferably the inlet air region 5 is separated from the
spray region 6 by means of a perforated bottom 10.
[0049] In particular the inlet air 9 is directed or guided through
the perforated bottom 10 from the inlet air region 5 into the spray
region 6.
[0050] The installation 1 preferably has a suspension tank 11 which
in the interior contains a suspension 12 or another fluid for the
coating process.
[0051] The suspension 12 is preferably supplied to the installation
housing 2 by means of a suspension pump 13 via a suspension line 14
and/or pumped into the installation housing 2.
[0052] Preferably in the spray region 6 there are one or more
nozzles 15 which are made to atomize the suspension 12 in the
installation housing 2, in particular in the spray region 6 and/or
to apply it to the pellets (not shown), preferably the pellets
being fluidized within the scope of the fluidized bed coating
process and/or moving as a fluidized bed in the spray region 6.
[0053] Preferably the nozzles 15 are each located in a pipe, in
particular in a Wurster pipe 16. The pellets are preferably routed
past the nozzles 15 in the Wurster pipe 16 and sprayed or coated
with the suspension 12 by means of the nozzles 15. Preferably the
pellets in the Wurster pipe 16 are routed or blown upward or
against gravity by means of the inlet air 9.
[0054] Outside the Wurster pipe 16 the pellets drop preferably in
the direction of the perforated bottom 10 and/or with gravity. In
this way the pellets are coated along an at least essentially
ellipsoidal path in the installation housing 2.
[0055] The illustrated embodiment is in particular a bottom spray
version, preferably the nozzles 15 pointing up. But other
embodiments or arrangements in the installation 1 and/or in the
installation housing 2 are also possible.
[0056] There is preferably a suggested filter system 17 in the
filter region 7.
[0057] The filter system 17 preferably has a connecting device 18
which is made to connect a filter 19 assigned to the filter system
17 to a cleaning device 20 which is likewise assigned to the filter
system 17. The connecting device 18 can be part of the filter 19 or
of the cleaning device 20 or connected hereto or can be implemented
separately.
[0058] The filter 19, preferably a particle filter, is preferably
located within the installation housing 2, in particular above the
spray region 6 and/or in the filter region 7 and/or in the region
of the housing outlet 4. But other arrangements and/or designs are
also possible.
[0059] The filter 19 preferably separates the spray region 6 from
the dome region 8, in particular in a gas-permeable and/or
particle-retaining manner.
[0060] Preferably the filter 19 has several filter sections 21
and/or is and/or can be divided into several filter sections 21.
Especially preferably the filter sections 21 are spaced
three-dimensionally apart from one another and/or are made as
separate units of the filter 19.
[0061] The filter sections 21 are quite especially preferably made
as elongated, tubular and/or cylindrical surface filters, in
particular as filter cartridges 22 which project preferably from
the dome region 8 into the filter region 7.
[0062] Preferably a medium to be filtered, in particular a raw gas
23, flows through the filter cartridge 22 during the filtration by
means of the filter 19 from the outside to the inside, as shown in
FIG. 1.
[0063] In particular the surface of the filter section 21 or of the
filter cartridge 22 is made as the filter inlet 24 and the inside
of the filter section 21 or of the filter cartridge 22 indicated by
broken lines is made as the filter outlet 25.
[0064] The medium, in particular a clean gas 26, which is cleaned
or filtered by means of the filter 19, is preferably routed into
the dome region 8 of the installation housing 2 preferably by means
of the connecting device 18 in order to subsequently leave the
installation housing 2 via the housing outlet 4 as exhaust air
27.
[0065] In particular that part of the suspension 12 which does not
adhere to the pellets is carried preferably as dust, in particular
as a suspension dust or raw gas 23, from the spray region 6 into
the filter region 7.
[0066] The filter 19 is made in particular to filter the dust-laden
air or raw gas 23 and then to direct it as clean gas 26--preferably
by means of the connecting device 18--into the dome region 8 and/or
to the housing outlet 4.
[0067] Preferably the filter 19 and/or individual filter sections
21 clogs increasingly with particles, in particular the suspension
dust, during filtration of the raw gas 23.
[0068] The cleaning device 20 is preferably made to clean the
filter 19. In particular the cleaning device 20 is made to remove
the dust of the suspension 12 or other particles from the filter 19
and/or from the filter surface and/or to convey it, in particular
blow it, from the filter region 7 into the spray region 6. In FIG.
1 the cleaning device 20 is not active or no cleaning is taking
place.
[0069] Especially preferably the cleaning device 20 is located at
least partially or completely in the installation 1, in particular
in the installation housing 2. In the illustrated arrangement the
cleaning device 20 is located in the dome region 8 and/or on the
clean gas side or above the filter 19 or individual filter sections
21. But other arrangements are also possible.
[0070] The cleaning device 20 preferably has one storage apparatus
28, in particular the storage apparatus 28 being made to supply the
cleaning device 2Q with a medium, in particular compressed air.
[0071] Preferably the storage apparatus 28 is located at least
partially, preferably completely, within the installation housing
2. The storage apparatus 28 is especially preferably located in the
dome region 8 and/or above the filter 19.
[0072] Preferably the installation 1, the filter system 17 and/or
the cleaning device 20 has or have a control apparatus 29. The
control apparatus 29 is made in particular to control or regulate
the cleaning device 20 and/or the cleaning of the filter 19.
[0073] In the illustrated embodiment the control apparatus 29 is
located preferably outside the installation housing 2. But other
arrangements are also possible.
[0074] Preferably the installation 1, the filter system 17, the
cleaning device 20 and/or the control apparatus 29 has or have at
least one pressure sensor 30, in particular the pressure sensor 30
being made to determine and/or measure a differential pressure
DP.
[0075] The differential pressure DP is preferably the difference
between two static pressures, dynamic pressures, or total pressures
of a fluid. In particular the differential pressure DP is the
difference of the preferably static pressure of the raw gas 23 and
of the preferably static pressure of the clean gas 26.
[0076] Preferably the differential pressure DP is determined and/or
measured between the filter inlet 24 and the filter outlet 25,
between the dome region 8 and one of the other regions of the
installation housing 2 and/or between the housing inlet 3 and
housing outlet 4 by means of the pressure sensor 30.
[0077] Preferably the control apparatus 29 controls or regulates a
valve 31 which is assigned in particular to the cleaning device 20
and/or the filter system 17 depending on the differential pressure
DP and/or according to the suggested cleaning method.
[0078] In particular one valve 31 at a time is assigned to each
filter section 21 or to each filter cartridge 22 and/or one filter
section 21 or one filter cartridge 22 at a time is fluidically
connected to one valve 31, especially preferably by means of the
respective connecting device 18. But other designs are also
possible, in particular in which a valve 31 is fluidically
connected to several filter sections 21.
[0079] Especially preferably the installation 1, the filter system
17, the cleaning device 20 and/or the control apparatus 29 is or
are made to determine and/or measure the differential pressure DP
with one or more pressure sensors 30 and/or to trigger the valve or
valves 31 to clean the filter 19.
[0080] Preferably the installation 1, the filter system 17, the
cleaning device 20 and/or the control apparatus 29 is or are made
to carry out a suggested cleaning method which is explained later
in the description.
[0081] By filtering the raw gas 23, with time a dust layer, in
particular a filter cake 32, forms on the surface of the filter 19,
in particular of the filter sections 21.
[0082] Preferably the mass or the volume, in particular the
thickness, and/or the density of the filter cake 32 increases
during the filtration and/or during operation of the installation
1.
[0083] In particular with or by the increase of the mass, of the
volume, and/or of the density of the filter cake 32 the
differential pressure DP likewise rises.
[0084] Preferably the differential pressure DP is at least
essentially a function of the mass, of the volume, and/or of the
density of the filter cake 32 and/or the differential pressure DP
correlates, in particular positively, with the mass, the volume
and/or the density of the filter cake 32.
[0085] In particular when the differential pressure DP reaches,
exceeds or approaches a given value, the control apparatus 29
controls or adjusts the valve or valves 31 preferably such that the
valve or valves 31 open and/or compressed air or some other medium
is blown or directed out of the storage apparatus 28 through the
valves or valves 31 and/or through the connecting device 18 into
the filter 19 and/or into one of the filter sections 21.
[0086] Preferably the differential pressure DP drops by and/or
during the cleaning of the filter 19 and/or of one of the filter
sections 21.
[0087] First of all, the suggested connecting device 18 is shown
isolated below using FIG. 2 and then in the installed state using
FIG. 3 and FIG. 4.
[0088] FIG. 2 shows a perspective view of the connecting device
18.
[0089] Preferably the connecting device 18 is made to connect the
filter 19 (not shown in FIG. 2) to the cleaning device 20 (not
shown), the connecting device 18 having one side wall 33 which
borders an internal cross section Q which increases along a
longitudinal axis L and has openings 34 with assigned major axes
H.
[0090] The connecting device 18 preferably has at least two, in
particular at least 50, especially preferably at least 100, and/or
at most 1000, especially at most 500, quite especially preferably
at most 400 openings 34.
[0091] Preferably the connecting device 18 is or can be divided
into at least two, preferably three regions or sections.
[0092] Preferably the openings 34 are located in a first section 35
of the connecting device 18. Especially preferably the connecting
device 18 has a second section 36 free of openings. In particular
the second section 36 is free of openings and/or is closed
laterally along the longitudinal axis L. The second section 36
preferably directly and/or continuously borders the first section
35 and/or forms with it an interruption-free or continuous flow
wall.
[0093] In particular the second section 36 has the internal cross
section Q which increases along the longitudinal axis L and/or the
greatest internal cross section Q1 at least in part.
[0094] Preferably each internal cross section Q of the second
section 36 is greater than one of the internal cross sections Q of
the first section 35.
[0095] The second section 36 extends preferably to at least 10%,
especially preferably to at least 20%, in particular to at least
30% and/or to at most 70%, especially preferably to at most 60%, in
particular to at most 50%, of the length or height of the
connecting device 18.
[0096] The connecting device 18 and/or the side wall 33 has or have
preferably a third section 37, preferably the third section 37
having a constant, in particular cylindrical internal cross section
Q. The third section 37 preferably directly borders the first
section 35, preferably on one side of the first section 35 facing
away from the second section 36.
[0097] The first section 35, the second section 36 and/or the third
section 37 are preferably tightly connected or made integral.
[0098] Preferably the internal cross section Q of the third section
37 is smaller than the internal cross section Q of the second
section 36 and/or smaller than or equal to the preferably smallest
internal cross section Q2 of the first section 35. In particular
the internal cross section Q of the third section 37 is the
smallest internal cross section Q2 of the connecting device 18.
[0099] In particular the first section 35 and/or the third section
37 has or have the smallest internal cross section Q2 of the
connecting device 18.
[0100] Preferably a width or a diameter of the smallest internal
cross section Q2 is greater than 33 mm and/or smaller than 70 mm,
preferably at least essentially equal to 50.8 mm (2 inches), and/or
a width or a diameter of the smallest internal cross section Q2 is
more than 20%, preferably more than 30%, and/or less than 60%,
preferably less than 50%, of a diameter or a width of the greatest
internal cross section Q1 of the connecting device 18.
[0101] Especially preferably the ratio of the surface of the filter
section 21 assigned to the connecting device 18 or of the filter
cartridge 22 assigned to the connecting device 18 at the least or
to the internal cross section Q2 of the connecting device 18
bordering the cleaning device 20 is an especially dimensionless
characteristic K.
[0102] The characteristic K can preferably be computed or expressed
via the following formula:
K=A.sub.Filter/Q=d.sub.Filter*L.sub.Filter*4/d.sub.Q.sup.2
preferably in the formula an at least essentially cylindrical
filter section 21 being assumed, and/or A.sub.Filter being the
surface of the filter section 21 assigned to the connecting device
18 or of the filter cartridge 22 assigned to the connecting device
18, Q being the smallest internal cross section Q2, d.sub.filter
being the inside or outside diameter of the filter section 21 or of
the filter cartridge 22, L.sub.Filter being the length or height of
the filter section 21 or of the filter cartridge 22 and d.sub.Q
being the diameter or the width of the smallest and of the internal
cross section Q2 or of the one bordering the cleaning device 20.
The characteristic K can be computed accordingly for different
filter geometries.
[0103] Preferably the ratio of the surface of the filter section 21
assigned to the connecting device 18 or of the filter cartridge 22
assigned to the connecting device 18 at the least or of the
internal cross section Q2 of the connecting device 18 bordering the
cleaning device 20 and the characteristic K is greater than 200, in
particular greater than 250, and/or less than 3000, in particular
less than 2500.
[0104] The internal cross section Q is preferably a (maximum)
internal cross sectional area perpendicular to the longitudinal
axis L of the connecting device 18 or a hydraulic cross section or
a hydraulic cross sectional area. In particular the internal cross
section Q is the area enclosed or bordered by the side wall 33 of
the connecting device 18.
[0105] Preferably on at least one axial end or in the opening or
mouth region the connecting device 18 has at least one connecting
apparatus, in particular a flange union 38 or a clamp union 39, in
particular the connecting apparatus being made to connect the
connecting device 18 to the filter 19 and/or the cleaning device
20, the valve 31 and/or the storage apparatus 28 by form-fit,
force-fit and/or by bonding.
[0106] The connecting device 18, in particular the connecting
apparatus(es) of the connecting device 18, is/are made preferably
to connect the connecting device 18 to the filter 19, the
connecting device 18 to the cleaning device 20, and/or the filter
19 to the cleaning device 20, especially in an immovable, holding,
supporting and/or rigid manner.
[0107] Especially preferably the connecting device 18 on the two
axial ends has one connecting apparatus each, as shown in FIG.
2.
[0108] The connecting apparatus(es) is/are preferably made as a
flange, clamp connection and/or screwed pipe joint and/or are
located on opposite axial ends of the connecting device 18, in
particular are formed integrally therewith.
[0109] In the embodiment shown in FIG. 2 the connecting device
18--preferably on the axial end of the second section 36--has a
flange union 38 and--preferably on the axial end of the third
section 37--a clamp union 39. However other designs are also
possible, in particular in which two axial ends of the connecting
device 18 have a flange union 38 or clamp union 39 as connecting
apparatus.
[0110] The connecting apparatus or connecting apparatuses can be
made both as groove unions or collar unions. In the illustrated
embodiment the flange union 38 is made preferably as a collar union
and the clamp union 39 is made preferably as a groove union.
[0111] Preferably the connecting apparatus has a groove 40,
preferably the groove 4Q being made to hold a seal 41.
[0112] The outside diameter of the connecting apparatus is
preferably larger than the outside diameter of the bordering
section of the connecting device 18. In particular the outside
diameter of the flange union 38 is greater than the maximum or
bordering outside diameter of the second section 36 and/or the
outside diameter of the clamp union 39 is greater than the maximum
or bordering outside diameter of the first section 35 and/or of the
third section 37.
[0113] As shown in FIG. 2, the internal cross section Q of the
connecting device 18 is made at least essentially circular. But
other designs are also possible, in particular in which the
internal cross section Q is made at least oval, rectangular or
square.
[0114] The connecting device 18 and/or the side wall 33 preferably
borders the internal cross section Q with one inside 42 of the side
wall 33.
[0115] Preferably the inside 42 runs conically along the
longitudinal axis L--at least in the first section 35 and/or in the
second section 36--and/or has an at least essentially straight
contour. Alternatively or additionally the inside 42 is shaped
bell-like, is bell-shaped or in the form of a diverging Laval
nozzle section. Preferably the inside 42 of the side wall 33 is
made at least essentially concave and/or convex.
[0116] In the illustrated embodiment the internal cross section or
the pitch of the internal cross section Q or of the inside 42 along
the longitudinal axis L or an angle enclosed between the
longitudinal axis L and a tangent of the side wall 33 decreases. In
particular the first section 35 has an internal cross section Q
which increases more dramatically along the longitudinal axis L
than the second section 36.
[0117] Preferably the connecting device 18, in particular the side
wall 33, has an outside 43, and preferably the profile or the
contour of the outside 43 can be made independent of the inside
42.
[0118] Preferably the outside 43 has an external cross section A
which increases along the longitudinal axis L. In the illustrated
embodiment the outside 43 runs along the longitudinal axis L at
least essentially parallel to the inside 42. But other approaches
are also possible.
[0119] In particular the outside 43--at least in the first section
35 and/or second section 36--is at least essentially straight
and/or the outside 43 has an at least essentially conical contour
or one which is arched in the longitudinal direction or is
bell-like. But other designs are also possible here.
[0120] FIG. 3 shows a schematic section of the connecting device 18
together with the valve 31 in the closed state and with one part of
one of the filter sections 21.
[0121] The transition between the first section 35 and second
section 36 and/or between the second section 36 and third section
37 is/are preferably at least essentially continuous. Especially
preferably the inside 42 at least in the first section 36 and/or in
the second section 37 is made continuous.
[0122] In the illustrated embodiment the outside 43--at least in
the first section 35 and in the second section 36--is made straight
and/or conical. But other designs are also possible here.
[0123] Preferably the thickness of the side wall 33 and/or the
difference between the internal cross section Q and the external
cross section A increases along the longitudinal axis L and/or with
increasing internal cross section Q.
[0124] In particular the internal cross section Q increases along
the longitudinal axis L with a first angle W1 which is greater than
5.degree. and/or less than 20.degree., preferably at least
essentially is equal to 12.degree., in particular an imaginary
extension or tangent of the inside 42 including the first angle W1
with the longitudinal axis L.
[0125] As shown in FIG. 3, the major axes H of the openings 34 run
obliquely to the side wall 33, in particular to the inside 42 of
the side wall 33. For purposes of illustration FIG. 3 shows only
the major axis H of one opening 34. The following explanations
however apply preferably to the major axes H of the other openings
34 accordingly.
[0126] Preferably the major axes H point from the outside to the
inside in the direction of an internal cross section Q which is
greater than an internal cross section Q into which the respective
opening 34 discharges.
[0127] Especially preferably the major axes H point from the
outside to the inside in the direction of greatest internal cross
section Q1 and/or intersect a plane imagined through the greatest
internal cross section Q1. In particular the major axes H point
from the outside to the inside in the direction of the filter 19,
as shown in FIG. 3.
[0128] Especially preferably the major axes H of the openings 34
intersect the longitudinal axis L at a second angle W2 and/or the
major axes H with the longitudinal axis L in a longitudinal
sectional view of the connecting device 18, as shown in FIG. 3,
include a second angle W2, preferably the second angle W2 being
less than 90.degree., preferably at least essentially equal to
45.degree..
[0129] Preferably the inside 42 includes with the major axis H, in
particular in the region of the respective mouth of the opening 34,
a third angle W3, in particular preferably the third angle W3 being
less than 90.degree. and/or greater than the first angle W1 and/or
the second angle W2.
[0130] The openings 34 are preferably oriented and/or located in
one or more planes E, in particular the planes E being aligned at
least essentially orthogonally to the longitudinal axis L of the
connecting device 18, as illustrated in FIG. 3 using two planes
E.
[0131] Preferably the planes E are each defined by at least three
openings 34. In particular at least three openings 34 lie and/or
discharge in one of the planes E.
[0132] Especially preferably each opening 34 is or can be assigned
to one of the planes E.
[0133] As shown in FIG. 3, the planes E along the longitudinal axis
L are arranged--preferably at least essentially
equidistantly--offset to one another and/or parallel to one
another. But other designs or arrangements are also possible.
[0134] The number of openings 34 per plane E increases preferably
with increasing internal cross section Q along the longitudinal
axis L.
[0135] Especially preferably the ratio of all cross sections of the
openings 34 of one plane E to the internal cross section Q into
which the openings 34 of the plane E discharge remains constant at
least essentially along the longitudinal axis L.
[0136] The openings 34--at least along the internal cross section Q
into which the respective openings 34 discharge, and/or in a plane
E--are arranged at least essentially circularly and/or form several
concentric circles along the longitudinal axis L.
[0137] In one alternative which is not shown the openings 34
alternatively or additionally are arranged in a latticed manner or
form a latticed structure.
[0138] The major axes H of the openings 34 of one of the planes E
preferably have one common intersection point, in particular the
intersection point lying on the longitudinal axis L.
[0139] The openings 34 are arranged uniformly distributed
preferably along the longitudinal axis L--at least in the first
section 35--and/or over the respective internal cross section Q.
Preferably the openings 34 in the respective plane E are
equidistantly offset to one another and/or arranged rotationally
symmetrically to one another.
[0140] In the embodiment shown in FIG. 3 the openings 34 are made
as a hole and/or have a circular cross section. But other
geometries are also possible, in particular the openings 34 having
an angular, in particular rectangular cross section and/or being
made as a slot, cylindrical, rotationally symmetrical and/or
axially symmetrical to the respective major axis H.
[0141] Preferably the openings 34 have a diameter and/or a width
which is more than 2% and/or less than 20%, preferably at least
essentially equal to 10% of the diameter and/or of the width of the
greatest internal cross section Q1.
[0142] In the illustrated embodiment the openings 34 each have at
least essentially the same diameter and/or the same width. But
other designs are also possible, in particular in which the
diameter and/or the width of the openings 34 per and/or in one
plane E and/or along the longitudinal axis L varies.
[0143] Preferably the openings 34 have a diameter and/or a width of
at least 5 mm and/or at most 40 mm, in particular of at least
essentially 20 mm.
[0144] The cross section of the mouth or the cross sectional area
of all openings 34 is together or cumulated preferably more than 2%
or 5%, in particular more than 8% or 10%, especially preferably
more than 12%, and/or less than 50% or 40%, in particular less than
30% or 20%, quite especially preferably less than 15%, of the area
of the inside 42 and/or outside 43.
[0145] The openings 34 are preferably made elongated and/or
tubular, preferably with a length which is greater than the
diameter and/or the width of the openings 34.
[0146] Preferably the internal cross section Q tapers in the
direction of the cleaning device 20 and/or of the valve 31 and/or
increases in the direction of the filter 19 and/or of the filter
sections 21.
[0147] The suggested cleaning device 20 preferably has the
connecting device 18 and/or is or can be connected to it. In
particular the valve 31 which is preferably assigned to the
cleaning device 20 and/or is an integral part of the cleaning
device 20, is fluidically connected to the connecting device 18, as
shown in FIG. 3.
[0148] The valve 31 is preferably made as an axial valve, as shown
for example in FIG. 3. But other designs are also possible.
[0149] Preferably the valve 31 is or can be driven pneumatically,
hydraulically and/or electrically. In the illustrated embodiment
the valve 31 is preferably driven pneumatically, in particular by
means of compressed air of the storage apparatus 28 (not
shown).
[0150] The valve 31 preferably has a piston 44, preferably the
piston 44 being movable axially and/or in the direction of the
longitudinal axis L.
[0151] In FIG. 3 the valve 31 is in the closed state.
[0152] In the closed state the piston 44 rests or lies on a cone
seat 45 located in the valve 31 such that flow through the valve 31
is prevented.
[0153] Preferably the piston 44 is pretensioned by means of a
spring 46 or some other tensioning element. To open the valve 31
the valve 31 preferably has a valve chamber 47. In particular the
pressure of a medium in the valve chamber 47 is or can be adjusted
or controlled by means of the control apparatus 29 (not shown).
[0154] Preferably the valve 31 opens when the pressure in the valve
chamber 47 is greater than the pressure produced by the spring
46.
[0155] The filter 19 shown in FIG. 3 or one of the filter sections
21 of the filter 19 preferably has one manifold 48 with several
holes 49. The manifold 48 is jacketed in particular by a filter
cloth 50.
[0156] The filter cloth 50 is preferably made to retain or filter
particles of a certain size, in particular the initially described
suspension dust.
[0157] Preferably during and/or by the filtration, as indicated in
FIG. 3, the filter cake 32 forms on the manifold 48 and/or the
filter cloth 50.
[0158] The arrows shown in FIG. 3 schematically illustrate the
preferred flow direction in the filter 19 and in the connecting
device 18 during filtration by means of the filter 19. The arrows
illustrate only schematically the flow direction; any turbulence,
eddies, detachments and/or other flow phenomena remain ignored.
[0159] In filtration by means of the filter 19 the medium to be
cleaned, in particular the raw gas 23, flows through the filter
section 21 at least essentially from the outside to the inside or
in the radial direction to the longitudinal axis L.
[0160] Flow through the connecting device 18 takes place during
filtration by means of the filter 19 in the second section 36
preferably at least essentially axially or along the longitudinal
axis L.
[0161] Subsequently or downstream the flow in the first section 35
during filtration is diverted such that it flows from the inside to
the outside through the openings 34.
[0162] Flow through the connecting device 18 and/or the openings 34
takes place preferably at least essentially from the inside to the
outside during filtration and/or the connecting device and/or
openings are made for flow through them to take place from the
inside to the outside during filtration.
[0163] In particular the suggested filter system 17 is made to
direct a medium, preferably the clean gas 26, from the inside or
one side facing the filter 19 to the outside or to one side facing
away from the filter 19 through the openings 34.
[0164] The connecting device 18 is made in particular to accelerate
a medium, in particular the clean gas 26, during filtration.
Especially preferably the connecting device 18 acts as a nozzle or
convergent tube during filtration.
[0165] FIG. 4 shows a schematic section of the connecting device 18
and of the filter 19 shown by way of an extract or of one of the
filter sections 21 according to FIG. 3 together with the valve 31
in the opened state.
[0166] Preferably the installation 1, the cleaning device 20 and/or
the control apparatus 29 (compare FIG. 1) is or are made to at
least essentially reverse the flow direction through the connecting
device 18, in particular through the openings 34, and/or through
the filter 19, in particular through one of the filter sections 21,
preferably by means of opening and closing of the valve 31.
[0167] FIG. 4 shows the cleaning of one of the filter sections 21
or the partial cleaning of the filter 19.
[0168] The connecting device 18 and/or the cleaning device 20 is or
are preferably made to retard a medium, in particular compressed
air from the storage apparatus 28 (compare FIG. 1) during and/or
for cleaning--in particular in the direction of increasing internal
cross section Q--and/or to raise the static pressure of the medium,
in particular of the compressed air of the storage apparatus 28--at
least in the connecting device 18.
[0169] Preferably the openings 34 are made to direct or suction
another medium, in particular the clean gas 26, from the outside to
the inside during and/or for cleaning. In particular the connecting
device 18 and/or the cleaning device 20 is or are made to increase
the mass flow of a medium, preferably of the compressed air of the
storage apparatus 28 and/or to suction a second medium, preferably
the clean gas 26--in particular through the and/or by means of the
openings 34.
[0170] The connecting device 18 acts preferably during and/or for
cleaning as a diffusor.
[0171] Especially preferably the action of the connecting device 18
depends on the flow direction through the connecting device 18.
[0172] Especially preferably flow takes place through the
connecting device 18 and/or the filter 19, in particular one of the
filter sections 21, during and/or for cleaning in one direction
which is preferably opposite at least essentially the flow
direction which prevails during and/or for filtration by means of
the filter 19.
[0173] In one especially preferred embodiment of the connecting
device 18 the connecting device 18 is made as a supercritical
diffusor and/or the internal cross section Q increases along the
longitudinal axis L with a first angle W1 greater than
8.degree..
[0174] The openings 34 are in particular made--at least during
and/or for cleaning--to prevent and/or reduce flow separation, in
particular at and/or on the inside 42 of the connecting device 18.
Especially preferably in the connecting device 18--at least during
cleaning--there is an at least essentially laminar flow and/or the
connecting device 18 is made to enable a laminar flow or to support
the formation of a laminar flow.
[0175] FIG. 5 shows a schematic plan view of the suggested filter
system 17 as well as of the suggested cleaning device 20 with the
storage apparatus 28 as well as one or more, in particular
synchronized, the control apparatus 29 which are made preferably to
control the valves 31 and/or to measure one or more differential
pressures DP assigned to the filter sections 21.
[0176] The storage apparatus 28 is preferably made to supply the
cleaning device 20 with a medium, in particular compressed air.
Especially preferably the storage apparatus 28 is assigned to the
filter system 17 and/or to the cleaning device 20 and/or is a
component of the filter system 17 and/or of the cleaning device
20.
[0177] Preferably the installation housing 2 has at least in part
in the interior the storage apparatus 28 or the storage apparatus
28 is located at least essentially within or in the interior of the
installation housing 2. In the embodiment shown in FIG. 5 the
storage apparatus 28 is made both in the interior of the
installation housing 2 and also outside of the installation housing
2.
[0178] Preferably the storage apparatus 28 optionally has one or
more storage units 51, as shown in FIG. 5, preferably the storage
units 51 being located outside the installation housing 2.
[0179] The storage apparatus 28 can be supplied from the outside
with medium or compressed air, in particular by fluid connections
between the storage unit(s) 51 and/or a compressor and the interior
which is formed or surrounded by the storage apparatus 28. But it
is also otherwise possible to supply compressed air or a medium to
the storage apparatus 28.
[0180] The storage apparatus 28 has in particular a ring reservoir
52 which is located in the interior of the installation housing
2.
[0181] Preferably the storage apparatus 28 and/or the ring
reservoir 52 is made at least essentially as a ring or is made
ring-shaped.
[0182] In the illustrated embodiment the storage apparatus 28
and/or the ring reservoir 52 extends in the upper region of the
installation housing 2, in particular in the dome region 8, and/or
above the filter system 17 or the filter 19. But other designs or
arrangements are also possible.
[0183] Preferably the storage apparatus 28 is made as a gas
reservoir, in particular as a reservoir for compressed air and/or
as a line network, in particular as a gas line network, especially
preferably as a compressed air line network. Especially preferably
the storage apparatus 28 is made to uniformly distribute and/or
deliver a medium, in particular compressed air, to the valves 31
and/or to the filter system 17.
[0184] In particular the storage apparatus 28 is made to supply
several filter sections 21 of the filter 19 with a medium, in
particular compressed air, individually and/or separated in
time.
[0185] Preferably the storage apparatus 28, in particular the ring
reservoir 52, has at least two pipe segments 53 and/or is made of
several pipe segments 53.
[0186] The pipe segments 53 are connected to one another or made
integral preferably by force-fit, form-fit and/or bonding, in
particular by welding.
[0187] The pressure of the medium in the storage apparatus 28 is
preferably more than 1 bar, in particular more than 2 bar, and/or
less than 10 bar, in particular less than 8 bar, especially
preferably less than 4 bar. The volume of the storage apparatus is
preferably more than 50 l, in particular more than 100 l,
especially preferably more than 200 l, and/or less than 1000 l, in
particular less than 800 l, especially preferably less than 500 l.
This has been found to be advantageous in conjunction with a
compact construction and good cleaning performance.
[0188] Preferably the storage apparatus 28, in particular the ring
reservoir 52, is fluidically connected to the valve 31 and/or the
connecting device 18.
[0189] Quite especially preferably the valve 31 is located in the
interior of the installation housing 2, in particular within the
storage apparatus 28 and/or between the storage apparatus 28 and
the connecting device 18. In particular the storage apparatus 28,
preferably the ring reservoir 52, is made to protect the valve 31
against an explosive atmosphere and/or to prevent direct contact of
the valve 31 with an explosive atmosphere, in particular direct
contact of the installation housing 2 and/or of the dome region
8.
[0190] Preferably the installation housing 2, the cleaning device
20 and/or the storage apparatus 28 has or have several lines for
supply of the cleaning device 20, of the storage apparatus 28, in
particular of the ring reservoir 52, and/or of the valve 31 with a
medium, in particular compressed air. In the embodiment shown in
FIG. 5 the storage apparatus 28 is preferably supplied by means of
a compressed air line 54 and/or the valve 31 is supplied by means
of a control air line 55.
[0191] The control air line 55 is preferably made to alternately
open or close the valve 31. Especially preferably the control
apparatus 29 controls or adjusts the valve 31 by means of the
control air line 55. Quite especially preferably the pressure in
the control air line 55 is greater than the pressure in the
compressed air line 54.
[0192] The installation housing 2 has preferably several
penetrations 56, in particular the compressed air line 54 and/or
the control air line 55 being routed through the penetration 56
from the outside to the inside into the installation housing 2.
[0193] Especially preferably the control apparatus 29 is made to
control the valve 31 for cleaning of the filter 19, in particular
of one of the filter sections 21.
[0194] In the embodiment shown in FIG. 5 the installation 1, the
filter system 17 and/or the cleaning device 20 preferably has or
have several control apparatus 29, preferably one control apparatus
29 at a time controlling or adjusting at least two valves 31.
[0195] The suggested cleaning method for sectional cleaning of the
filter 19 is detailed below using FIGS. 6 to 10.
[0196] The cleaning method is executed preferably by means of the
installation 1, the filter system 17, the connecting device 18, the
cleaning device 20 and/or the control apparatus 29.
[0197] FIGS. 6 and 7 show the installation 1, the filter system 17,
the connecting device 18, the cleaning device 20 and the control
apparatus 29 as the suggested cleaning method is being carried
out.
[0198] The filter system 17 or the filter 19 is cleaned in sections
or partially during the cleaning method.
[0199] Preferably the filter system 17 or the filter 19 has at
least two, preferably at least three, in particular at least four,
filter sections 21, in particular filter cartridges 22, by means of
a cleaning process 57 one of the filter sections 21 or one of the
filter cartridges 22 at a time being cleaned, as shown in FIGS. 6
and 7.
[0200] Preferably in the suggested cleaning method the filter
sections 21 are cleaned in cleaning processes 57 which are offset
to one another or separated in time from one another. In particular
the filter sections 21 are cleaned in cleaning processes 57
separated from one another by a time interval T1.
[0201] Preferably in the cleaning method a cleaning process 57 is
completely finished or ended before a further cleaning process 57
starts.
[0202] Especially preferably all filter sections 21 or filter
cartridges 22 of the filter 19 and/or the entire filter 19 are
cleaned within one cleaning cycle 58.
[0203] In particular the cleaning method has at least two cleaning
cycles 58.
[0204] Preferably the end of one cleaning cycle 58 is separated in
time by a time interval T2 from the start of a following cleaning
cycle 58.
[0205] Preferably the (second) cleaning cycle 58 which follows a
(first) cleaning cycle 58 is the (second) cleaning cycle 58 which
directly follows the (first) cleaning cycle 58, in particular
between the end of the (first) cleaning cycle 58 and the start of
the (second) cleaning cycle 58 or during the time interval T1
and/or T2 no cleaning process 57 being triggered or carried
out.
[0206] As shown in FIGS. 6 and 7, the filter system 17 or the
filter 19 has especially preferably at least three filter sections
21, the filter sections 21 being cleaned in cleaning processes 57
separated from one another by time intervals T1.
[0207] Preferably a cleaning process 57 and/or a cleaning cycle 58
is triggered by opening the assigned valve 31, preferably one valve
31 being assigned to one filter section 21 or filter cartridge 22
at a time or one filter section 21 at a time being cleanable by
opening of the corresponding valve 31.
[0208] In particular, as already explained at the beginning, by
triggering a cleaning process 57 the flow direction of the
pertinent filter section 21 or of the pertinent filter cartridge 22
is reversed.
[0209] As shown in FIGS. 6 and 7, preferably the filtration is
continued during cleaning of one of the filter sections 21 by means
of the other filter sections 21. But other versions of the method
are also possible, in particular in which filtration is stopped or
adjusted during the cleaning process 57.
[0210] FIG. 6 shows the cleaning of a first filter section 21 or a
first filter cartridge 22, in particular compressed air being
directed from the storage apparatus 28 through the assigned valve
31 and the suggested connecting device 18 into the filter section
21 or the filter cartridge 22, in particular by the valve 31 being
opened.
[0211] Preferably during the cleaning process 57 in addition to
compressed air from the storage apparatus 28 another medium, in
particular the clean gas 26, is directed into the filter section 21
or the filter cartridge 22, as is indicated by arrows in FIG. 6 and
FIG. 7.
[0212] FIG. 7 shows the cleaning process 57 of another, second
filter section 21 or another filter cartridge 22.
[0213] Preferably, in the suggested cleaning method, filter
sections 21 adjacent to one another are cleaned in cleaning
processes 57 offset in time from one another, as shown by means of
FIG. 6 and FIG. 7. Especially preferably the sequence in which the
filter sections 21 are cleaned remains identical in each cleaning
cycle 58. But other versions of the method are also possible, in
particular in which the sequence in which the filter sections 21
are being cleaned is varied with each cleaning cycle 58.
[0214] In one quite especially preferable version of the method, in
one cleaning cycle 58 first those filter sections 21 are cleaned
which have the greatest distance to the compressed air line 54.
[0215] In the suggested cleaning method preferably the time
interval T1 between the cleaning processes 57, in particular within
the respective cleaning cycle 58, and/or the time interval T2
between the end of one of the at least two cleaning cycles 58 is or
are changed.
[0216] In particular the time intervals T1 between successive
cleaning processes 57 in the cleaning method are changed. In the
sense of this invention the feature that "two cleaning processes 57
follow one another" should preferably be understood such that no
further cleaning process 57 takes place between the two successive
cleaning processes 57. The corresponding applies to successive
cleaning cycles 58.
[0217] If the filter 19 has at least three filter sections 21, in
the cleaning method the time interval T1 between the successive
cleaning process 57 of a first and a second filter section 21 and
the time interval T2 between the successive cleaning processes 57
of the second and a third filter section 21 are each changed.
[0218] Preferably the time interval T1 and/or the time interval T2
is or are changed by means of feedback control 59 and/or feedback
control 59 is carried out in the suggested cleaning method and
causes a change or variation of the time intervals T1 and T2.
[0219] FIG. 8 shows in this regard a schematic block diagram of the
feedback control 59 underlying the suggested cleaning method or of
the feedback control circuit of the feedback control 59.
[0220] Preferably in the cleaning method and/or the feedback
control 59 the differential pressure DP between the filter inlet 24
and the filter outlet 25 is adjusted and/or used as a controlled
variable 60 in the feedback control 59.
[0221] Preferably a rated differential pressure SP as a reference
variable 61 is specified in particular exogenously to the feedback
control 59.
[0222] The rated differential pressure SP is preferably more than
1000 Pa, in particular more than 2000 Pa, especially preferably
more than 3000 Pa, and/or less than 7000 Pa, in particular less
than 6000 Pa, especially preferably less than 5000 Pa. Quite
especially preferably the rated differential pressure SP is at
least essentially 4000 Pa.
[0223] Preferably the rated differential pressure SP in the
cleaning process is kept constant. But other versions of the method
are also possible in which the rated differential pressure SP is
changed.
[0224] Preferably the difference between the rated differential
pressure SP and the differential pressure DP is used as the system
deviation 62 in the feedback control 59 and/or in the cleaning
method.
[0225] The feedback control 59 and/or the cleaning method uses or
use preferably one controller, in particular a PID controller 63.
But it is also possible to use other controllers in the feedback
control 59 and/or in the cleaning method.
[0226] The triggering of a cleaning process 57 and/or the opening
of the valve 31 or of one of the valves 31 or the length of the
time interval T1 and/or T2 is preferably used as a manipulated
variable 64 in the feedback control 59 and/or in the cleaning
method.
[0227] The controller is preferably made to determine the
manipulated variable 64 by means of the system deviation 62, in
particular the system deviation 62 multiplied by a factor being
integrated and/or derived over a fixed time.
[0228] The cleaning method and/or the feedback control 59
preferably uses the filter system 17 and/or the cleaning device 20,
preferably together with the storage apparatus 28 as the controlled
system 65.
[0229] As shown in FIG. 8, optionally one influencing quantity 66
acts on the cleaning method and/or the feedback control 59, in
particular on the controlled system 65. In particular possible
influencing quantities 66 include the increasing clogging or
fouling of the filter 19, in particular of the filter sections 21,
and/or the formation or increase of the filter cake 32, the degree
of dust loading of the raw gas 23, the flow velocity in the
installation housing 2, quantity and quality of the suspension 12
supplied to the installation housing 2 and/or quantity and quality
of the inlet air 9 supplied to the installation housing 2.
[0230] In the cleaning method and/or in the feedback control 59 the
differential pressure DP and or the system deviation 62 is
preferably filtered with a control filter 67, preferably with a
lowpass characteristic and/or such that peaks or fluctuations of
the differential pressure DP caused by a cleaning process 57 and/or
the cleaning processes 57 of one cleaning cycle 58 are at least
essentially suppressed and/or filtered.
[0231] As already explained, the time interval T1 between two
successive cleaning processes 57 and/or the time interval T2
between two successive cleaning cycles 58 with several cleaning
processes 57 each is each determined by feedback control 59 which
preferably has the control filter 67.
[0232] The control filter 67 is preferably made or designed such
that both the pressure peaks which are produced by the respective
cleaning process 57, in particular by feed of compressed air, and
also pressure deviations based on the differential pressure DP
which has changed after the completion of a cleaning process 57 are
smoothed and/or averaged.
[0233] Preferably the control filter 67 has a three-dB corner
frequency or critical frequency of one preferred lowpass
characteristic which is smaller than 1/(2.times..pi..times.time
constant), the time constant preferably being greater than the
minimum time interval T1, the minimum time interval T2 and/or
greater than 1 s, preferably greater than 2 s or 4 s, in particular
greater than 5 s. Alternatively or additionally the time constant
is preferably smaller than the sum of the time intervals T1 of the
cleaning processes 57 of one cleaning cycle 58, less than 30 s,
preferably less than 25 s, especially preferably less than 20 s or
15 s. The control filter 67 can however have a filter
characteristic other than a lowpass characteristic, its being
preferred that it is made to smooth deviations of the differential
pressure DP which have been caused by cleaning processes 57.
[0234] The differential pressure DP or the difference between the
differential pressure DP and rated differential pressure SP in the
sense of this invention is then regarded as smoothed when the
deviations caused by or in a cleaning process 57 are reduced or
damped by more than 10%, preferably more than 20%, in particular
more than 30% or 40%.
[0235] In one especially preferably embodiment the feedback control
59 is designed such that the control filter 67 damps frequencies
above 10 Hz, preferably above 5 Hz, in particular above 2 Hz or 1
Hz, by more than 50%.
[0236] FIG. 9 shows a schematic of the pressure P as a function of
the time T in the suggested cleaning method according to a first
version of the method.
[0237] In the illustrated cleaning method preferably five filter
sections 21 are cleaned by means of one cleaning process 57 at a
time in one cleaning cycle 58, the time intervals T1 between the
cleaning processes 57 being changed each time.
[0238] In the illustrated example the time intervals T1 between the
cleaning processes 57 become smaller with increasing clogging or
fouling of the filter sections 21, in particular of the filter
cloth 50 and/or with time.
[0239] Preferably the time at which a cleaning process 57 is
completed or takes place is less than 10 s, in particular less than
5 s, especially preferably less than 2 s. Quite especially
preferably the time of one cleaning process 57 is at least
essentially 1 s.
[0240] Preferably the time for one cleaning process 57 is less than
the time which cleaned particles, in particular the suspension dust
and/or the filter cake 32 requires or require to travel or fall out
of the immediate suction area of the respective filter section 21
during the cleaning process 57.
[0241] In particular during and/or after one cleaning process 57
refiltration of particles cleaned by the cleaning process 57 is
prevented, avoided or reduced.
[0242] Preferably the time intervals T1 between the cleaning
processes 57 are limited with a maximum value and/or a minimum
value, preferably the maximum value and/or the minimum value being
specified exogenously to the feedback control 59 and/or the
cleaning method.
[0243] Especially preferably the maximum value is less than 500 s,
in particular less than 400 s, especially preferably less than 300
s, and/or the minimum value is more than 5 s, in particular more
than 10 s, especially preferably more than 15 s.
[0244] Preferably the differential pressure DP rises during
filtration by means of the filter 19, in particular when a cleaning
process 57 is not taking place.
[0245] In the illustrated characteristic the differential pressure
DP increases preferably at least essentially linearly with the time
T or the difference between the differential pressure DP and the
rated differential pressure SP decreases essentially linearly with
the time T. But other curve characteristics are also possible.
[0246] A cleaning process 57 is preferably triggered when the
differential pressure DP reaches the rated differential pressure
SP, exceeds it and/or approaches it. In particular a cleaning
process 57 is triggered depending on the differential pressure DP,
the system deviation 62 and/or on the preferably previous time
interval T1 and/or the time interval T2. Especially preferably the
controller of the feedback control 59 determines the instant of
triggering of a cleaning process 57 or the start of a cleaning
cycle 58.
[0247] Preferably the differential pressure DP drops during the
cleaning process 57 and/or by the cleaning process 57. In
particular the difference between the differential pressure DP and
the rated differential pressure SP increases during the cleaning
process 57 and/or by the cleaning process 57.
[0248] As shown in FIG. 9, the differential pressure DP rises again
after completion of the cleaning process 57 or the difference
between the differential pressure DP and the rated differential
pressure SP decreases.
[0249] Especially preferably the differential pressure DP after
cleaning or after one cleaning process 57 rises linearly and/or at
least essentially as before cleaning or a cleaning process 57. But
other curve characteristics are also possible, in particular in
which the gradient of the differential pressure DP increases with
the time T and/or with the number of triggered cleaning processes
57.
[0250] Depending on the controller of the feedback control 59,
after a first cleaning process 57 another cleaning process 57 is
triggered, in particular when the differential pressure DP again
reaches, exceeds and/or approaches the rated differential pressure
SP.
[0251] Preferably the differential pressure DP drops in a cleaning
process 57 at least essentially to the same value as in the
previous cleaning process 57 or the differential pressure DP after
successive cleaning processes 57 is at least essentially the
same.
[0252] As FIG. 9 illustrates, the differential pressure DP which
prevails immediately after completion of a cleaning process 57
increases with the time T.
[0253] In particular the time until the differential pressure DP
reaches the rated differential pressure SP, exceeds it and/or
approaches the rated differential pressure SP decreases with the
time T.
[0254] The time interval T1 between two successive cleaning
processes 57, in particular between the start of two successive
cleaning processes 57 and/or the end of two successive cleaning
processes 57 and/or the end of one temporarily and the start of a
following cleaning process 57 becomes preferably at least
essentially exponentially smaller preferably during filtration by
means of the filter 19 and/or with the time T.
[0255] Especially preferably with the suggested cleaning method the
time interval T1 and/or the time interval T2 is adjusted and/or
used as a controlled variable 60 or controlled variables 60 in the
feedback control 59.
[0256] In particular the time interval T1 and/or the time interval
T2 is/are used as the manipulated variable 64 or manipulated
variables 64 in the feedback control 59 or in the cleaning
method.
[0257] Especially preferably the time intervals T1 and T2 are not
directly derived from the differential pressure DP or the
comparison of the differential pressure DP to the rated
differential pressure SP. It is preferred that the time interval T1
and the time interval T2 are computed, defined or determined by the
feedback control 59, especially preferably by means of the control
apparatus 29.
[0258] In the illustrated curve characteristic all five filter
sections 21 are cleaned in one cleaning cycle 58. Preferably after
the end of the illustrated cleaning cycle 58 one following cleaning
cycle 58 (not shown) begins.
[0259] FIG. 10 shows a schematic representation of the pressure P
as a function of the time T in the suggested cleaning method
according to a second version of the method, in particular the time
interval T1 being at least essentially constant within one cleaning
cycle 58.
[0260] Preferably one cleaning process 57 is triggered at the start
of the respective cleaning cycle 58 when the differential pressure
DP reaches the rated differential pressure SP, exceeds it and/or
approaches the rated differential pressure SP.
[0261] Preferably the time interval T1 between successive cleaning
processes 57 of one cleaning cycle 58 is changed in particular by
means of the above explained feedback control 59 and/or for the
entire cleaning cycle 58 is fixed at an at least essentially
constant value. In particular the subsequent cleaning processes 57
take place within the cleaning cycle 58 regardless of the
differential pressure SP and/or the rated differential pressure SP
and/or after the time interval T1.
[0262] The time interval T1 between successive cleaning processes
57 within one cleaning cycle 58 is preferably changed and/or fixed
before and/or at the start of the cleaning cycle 58, preferably by
means of the feedback control 59 and/or is held constant at the
previously established value during the entire cleaning cycle
58.
[0263] As FIG. 10 shows, in this version of the method the
differential pressure DP which prevails at the start of one
cleaning process 57 and/or at the end of one cleaning process 57
can drop and/or rise within one cleaning cycle 58.
[0264] In the illustrated example the filter 19 preferably has
three filter sections 21 and/or one cleaning cycle 58 encompasses
three cleaning processes 57.
[0265] If all filter sections 21 in one cleaning cycle 58 are
cleaned by means of the cleaning processes 57, the cleaning cycle
58 is ended.
[0266] Preferably after completion of one cleaning cycle 58
separated in time by the time interval T2 a further following
cleaning cycle 58 starts, in particular the time interval T2 of
successive cleaning cycles 58 being changed.
[0267] Preferably another cleaning cycle 58 starts with the
triggering of a cleaning process 57. As shown in FIG. 10, the time
intervals T1 in the second cleaning cycle 58 are changed compared
to the first cleaning cycle 58.
[0268] Preferably the time intervals T1 from cleaning cycle 58 to
cleaning cycle 58 and/or with the time T become smaller. But other
variations are also possible.
[0269] Preferably the differential pressure DP with time T
increasingly approaches the rated differential pressure SP.
[0270] When the differential pressure DP can no longer be adjusted
by means of the cleaning method and/or the feedback control 59, in
particular when the differential pressure DP exceeds the rated
differential pressure SP by a previously fixed value and/or the
time interval T1 and/or the time interval T2 reaches a previously
established minimum value, the filter 19 is preferably completely
cleaned, in particular wet, preferably the installation 1 and/or
the filter system 17 being shut down and/or the filtration being
adjusted by means of the filter 19.
[0271] Preferably the time intervals T1 are changed such that the
number of cleaning processes 57 is minimized and/or the time until
necessary wet cleaning of the filter 19 is maximized.
[0272] Individual aspects and features of the different embodiments
and versions of the method can be implemented independently of one
another, but also in any combination with one another.
REFERENCE NUMBER LIST
[0273] 1 installation [0274] 2 installation housing [0275] 3
housing inlet [0276] 4 housing outlet [0277] 5 inlet air region
[0278] 6 spray region [0279] 7 filter region [0280] 8 dome region
[0281] 9 inlet air [0282] 10 perforated bottom [0283] 11 suspension
tank [0284] 12 suspension [0285] 13 suspension pump [0286] 14
suspension line [0287] 15 nozzle [0288] 16 Wurster pipe [0289] 17
filter system [0290] 18 connecting device [0291] 19 filter [0292]
20 cleaning device [0293] 21 filter sections [0294] 22 filter
cartridge [0295] 23 raw gas [0296] 24 filter inlet [0297] 25 filter
outlet [0298] 26 clean gas [0299] 27 exhaust air [0300] 28 storage
apparatus [0301] 29 control apparatus [0302] 30 pressure sensor
[0303] 31 valve [0304] 32 filter cake [0305] 33 side wall [0306] 34
opening [0307] 35 first section (with openings) [0308] 36 second
section (free of openings) [0309] 37 third section (cylindrical)
[0310] 38 flange union [0311] 39 clamp union [0312] 40 groove
[0313] 41 seal [0314] 42 inside (side wall) [0315] 43 outside (side
wall) [0316] 44 piston [0317] 45 cone seat [0318] 46 spring [0319]
47 valve chamber [0320] 48 manifold [0321] 49 hole [0322] 50 filter
cloth [0323] 51 storage unit [0324] 52 ring reservoir [0325] 53
pipe segment [0326] 54 compressed air line [0327] 55 control air
line [0328] 56 penetration [0329] 57 cleaning process [0330] 58
cleaning cycle [0331] 59 feedback control [0332] 60 controlled
variable [0333] 61 reference variable [0334] 62 system deviation
[0335] 63 PID controller [0336] 64 manipulated variable [0337] 65
controlled system [0338] 66 influencing quantity [0339] 67 control
filter [0340] A outside cross section [0341] E plane [0342] H major
axis [0343] L longitudinal axis [0344] Q internal cross section
[0345] Q1 largest internal cross section [0346] Q2 smallest
internal cross section [0347] P pressure [0348] DP differential
pressure [0349] SP rated differential pressure [0350] T time [0351]
T1 time interval (cleaning process) [0352] T2 time interval
(cleaning cycle) [0353] W1 first angle [0354] W2 second angle
[0355] W3 third angle
* * * * *