NZ625668B2 - A method for monitoring the operation of a liquid food processing system - Google Patents
A method for monitoring the operation of a liquid food processing system Download PDFInfo
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- NZ625668B2 NZ625668B2 NZ625668A NZ62566812A NZ625668B2 NZ 625668 B2 NZ625668 B2 NZ 625668B2 NZ 625668 A NZ625668 A NZ 625668A NZ 62566812 A NZ62566812 A NZ 62566812A NZ 625668 B2 NZ625668 B2 NZ 625668B2
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- New Zealand
- Prior art keywords
- pressure difference
- food processing
- cleaning
- processing system
- section
- Prior art date
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- 235000021056 liquid food Nutrition 0.000 title claims abstract description 37
- 235000013305 food Nutrition 0.000 claims abstract description 59
- 238000004140 cleaning Methods 0.000 claims description 92
- 239000003599 detergent Substances 0.000 claims description 32
- 239000012530 fluid Substances 0.000 claims description 32
- 239000002253 acid Substances 0.000 claims description 18
- 239000000047 product Substances 0.000 claims description 16
- 239000007788 liquid Substances 0.000 claims description 14
- 230000000977 initiatory Effects 0.000 claims description 13
- 238000010438 heat treatment Methods 0.000 claims description 12
- 230000015654 memory Effects 0.000 claims description 12
- 239000012459 cleaning agent Substances 0.000 claims description 10
- 235000013365 dairy product Nutrition 0.000 claims description 8
- 239000012263 liquid product Substances 0.000 claims description 5
- 150000002500 ions Chemical class 0.000 claims description 3
- 229940035295 Ting Drugs 0.000 claims description 2
- 238000009434 installation Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 description 37
- 210000004080 Milk Anatomy 0.000 description 16
- 239000008267 milk Substances 0.000 description 16
- 235000013336 milk Nutrition 0.000 description 16
- 239000003795 chemical substances by application Substances 0.000 description 4
- 230000001276 controlling effect Effects 0.000 description 4
- 239000000126 substance Substances 0.000 description 3
- 230000001419 dependent Effects 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 102000004169 proteins and genes Human genes 0.000 description 2
- 108090000623 proteins and genes Proteins 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000003513 alkali Substances 0.000 description 1
- 235000008452 baby food Nutrition 0.000 description 1
- 230000006399 behavior Effects 0.000 description 1
- 230000002596 correlated Effects 0.000 description 1
- 230000003247 decreasing Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 239000008237 rinsing water Substances 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 235000014347 soups Nutrition 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 230000002522 swelling Effects 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
- A23C7/00—Other dairy technology
- A23C7/02—Chemical cleaning of dairy apparatus; Use of sterilisation methods therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/04—Cleaning involving contact with liquid
- B08B3/08—Cleaning involving contact with liquid the liquid having chemical or dissolving effect
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto
- B08B9/02—Cleaning pipes or tubes or systems of pipes or tubes
- B08B9/027—Cleaning the internal surfaces; Removal of blockages
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto
- B08B9/02—Cleaning pipes or tubes or systems of pipes or tubes
- B08B9/027—Cleaning the internal surfaces; Removal of blockages
- B08B9/032—Cleaning the internal surfaces; Removal of blockages by the mechanical action of a moving fluid, e.g. by flushing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto
- B08B9/02—Cleaning pipes or tubes or systems of pipes or tubes
- B08B9/027—Cleaning the internal surfaces; Removal of blockages
- B08B9/032—Cleaning the internal surfaces; Removal of blockages by the mechanical action of a moving fluid, e.g. by flushing
- B08B9/0321—Cleaning the internal surfaces; Removal of blockages by the mechanical action of a moving fluid, e.g. by flushing using pressurised, pulsating or purging fluid
- B08B9/0325—Control mechanisms therefor
Abstract
Disclosed is a liquid food processing system. The system comprises at least one section (110, 120) through which liquid food products are flowing during food processing and causing build-up of deposits within the section (110, 120). The system also comprises at least one sensor (112, 114, 122, 124) configured to determine a pressure difference across the at least one section for monitoring removal or build-up of the deposits. configured to determine a pressure difference across the at least one section for monitoring removal or build-up of the deposits.
Description
A method for monitoring the operation of a liquid food processing system
cal Field
The present invention relates to a method of monitoring the operation of a
liquid food processing system. More ularly, the present invention relates to a
method for monitoring and optimizing operation parameters of a liquid food processing
system.
Background
A liquid food processing system, such as a dairy system, includes a plurality
of food processing equipments arranged in several sections wherein each section is
designed to provide a specific treatment of the food. For example, a dairy system may
include a separating section, a filtering section, a homogenisation section, and a heat
treatment section such as ultra high temperature (UHT) ent.
When liquid food is transported through the different sections soil layers are
known to be deposited on the or walls of the equipment. Such deposition,
ly denoted as fouling, s the performance of the equipment and must be
removed at regular intervals in order to maintain high performance of the food
sing system.
The provision of fouling may be monitored and measured as described in
US4521864, in which a method for determining the fouling thickness by ing the
relationship between fluid flow velocity and pressure difference is described.
The traditional way of cleaning equipment, which has previously been done by
disconnecting the fouled equipment and reconnect it after cleaning, has in many
ations been replaced by a so called cleaning-in-place (CIP) process. In such
method the food to be processed is prevented from flowing through the particular
section to be cleaned, and the food is redirected after cleaning of the ent. As
the ng process is done without dismounting the equipment the overall running
time of the sing system is increased icantly.
In food processing applications the CIP process is a sequential process in
which chemical agents are introduced into the equipment and upon flowing through the
equipment the agents will dissolve the fouling or remove it by mechanical impact. For
this, the chemical agent is usually switched between an acid detergent and an alkaline
detergent for a number of cycles, where the flowing time for each detergent is varied in
order to provide sufficient cleaning and removal of the fouling.
gh the known CIP-processes provide ient cleaning of the
processing equipment, there are always high demands on zing the required
cleaning time. Therefore it is of high importance to monitor the ion of a liquid
food processing system, as well as to improve cleaning of such liquid food sing
systems.
Summary
It is, therefore, an object of the present invention to overcome or alleviate the
above described problems.
The basic idea is to e a method for monitoring the operation of a liquid
food processing system in order to determine the removal or build-up of deposits.
Further, an idea is to monitor the cleaning process such that the operating
parameters of a CIP cycle may be adjusted in order to obtain maximum cleaning in
minimum time.
A further idea is to measure the re ence caused by the fouling,
and continuously monitor the pressure ence decrease as the cleaning proceeds.
A yet further idea is to e the measured pressure difference with a
reference value for creating a pressure difference ratio.
A yet r idea is to provide a method for dividing the food processing
system into at least one CIP circuit, and performing and monitoring cleaning of that
particular circuit.
According to a first aspect, a method for monitoring the operation of a liquid
food processing system is provided. The method comprises the steps of initiating a
fluid flow through at least one section of said food processing system; and determining
a pressure difference across said at least one section during said fluid flow for
monitoring removal or build-up of ts, said removal or build-up being caused by
said fluid flow.
The method further comprises the step of comparing said determined
pressure ence with a reference value.
The method may further comprise the step of dividing said ined
pressure difference with said reference value for calculating a pressure difference ratio.
Said reference value may represent the pressure difference across said
section when said section is considered as being sufficiently clean.
Said pressure difference may be determined continuously during said fluid
flow.
Said determined re difference may comprise a value representing the
pressure difference derivative, and the method may further comprise the step of
comparing said value with a re difference reference derivative. The pressure
difference reference value may be calculated by measuring a volume flow of said fluid
flow through said section when being sufficiently clean, and multiplying the square of
said volume flow with a predetermined nt.
The method may r comprise the step of dividing said liquid food
sing system into at least two sections, wherein said pressure difference is
determined across each section during said fluid flow.
According to a second aspect, a method for optimizing the operation of a
liquid food processing system is ed. The method ses the steps of
monitoring said operation according to the first aspect, and stopping said fluid flow
when the determined pressure difference equals a predetermined value.
Said fluid flow may be provided by initiating a cleaning step including flowing a
cleaning agent through a cleaning-in-place circuit of said liquid food processing
system, wherein the method may further comprise the step of changing at least one
cleaning step parameter during said cleaning step.
Said at least one cleaning step parameter may be selected from the group
consisting of: cleaning step duration, cleaning agent temperature, cleaning agent flow,
and cleaning agent concentration.
The method may further comprise the step of initiating a subsequent cleaning
step after stopping the monitored cleaning step. Said subsequent cleaning cycle may
be a rinsing step, a dosing of alkaline detergent step, a ation of alkaline ent
step, a dosing of acid detergent step, or a circulation of acid detergent step.
The method of monitoring said operation may be repeated for said
subsequent cleaning step.
Said fluid flow may be provided by initiating a liquid product flow through said
liquid food processing system, wherein the method may further comprise the step of
changing at least one product flow parameter during said product flow.
The method may further comprise the step of initiating a rinsing step after
stopping the monitored liquid product flow.
The method may r se the step of ting a cleaning-in-place
cycle after said rinsing step.
The method may further comprise the step of identifying the product being
processed by said liquid food processing system, and wherein said ermined
value of the pressure difference is associated with said product.
Said liquid food processing system may be a dairy system.
ing to a third aspect, a liquid food processing system is provided. The
food processing system ses at least one section through which liquid food
products are flowing during food sing and causing build-up of deposits within
said section, and at least one sensor configured to determine a pressure difference
across said at least one section for monitoring removal or build-up of said deposits.
The at least one sensor may include two sensors ed at a first end and a
second end of said section.
The food processing system may further comprise a ining unit
connected to said sensors and being configured to calculate said pressure difference.
r, the food processing system comprises a calculating unit ured to
receive said determined pressure difference and to compare said pressure difference
with a reference value.
The food processing system may r comprise a cleaning-in-place circuit
for removing said deposits by initiating a cleaning cycle including at least one step of
flowing cleaning fluid through said at least one n.
The food sing system may further comprise a controller configured to
e said ined pressure difference, wherein said controller is further
connected to a pump and/or heating units of said sections and/or a feeding tank for
ng the operating parameters of said pump and/or said g units depending
of the received pressure difference.
The controller may be connected to a remote reference memory g data
representing said operating parameters as a function of pressure difference.
The remote reference memory may be connected to several food processing
systems such that each processing system receives data representing said operating
parameters from said reference memory.
According to a fourth aspect, a kit of parts for installation in a liquid food
processing plant is provided. The kit of parts comprises a volume flow sensor for
measuring a volume flow of a reference fluid flow, a calculator for determining a
reference pressure difference from said measured volume flow, a re difference
sensor for measuring a pressure difference of an actual fluid flow, and a controller for
comparing said measured pressure difference with said reference pressure difference
for monitoring removal or build-up of deposits during said actual fluid flow.
Liquid food product is defined as a food product being possible to pump
through a food processing line. Hence, liquid food product includes food products
having different viscosities as well as arbitrary amount of solid content. Liquid food
product is thus defined as a common term for , milk, juice, soups, purée, baby
food, etc.
Brief Description of Drawings
The above, as well as additional objects, features, and advantages of the
present ion, will be better understood through the following illustrative and non-
limiting detailed description of red embodiments of the present invention, with
reference to the appended gs, wherein:
Fig. 1 is a s scheme for a food processing system utilizing a method
according to an embodiment;
Fig. 2 is a m showing removal of fouling as a function of cleaning
parameters for a first section of a food processing system;
Fig. 3 is a diagram showing removal of fouling as a function of cleaning
parameters for a second section of a food processing system; and
Fig. 4 is a s scheme of a food processing system according to an
embodiment.
Detailed Description
As will be further described below, a method for monitoring cleaning-in-place
parameters of a food processing system is provided which method includes the step of
ing the pressure difference during the ng process. The measured
pressure difference is correlated to the degree of fouling, as a reduction in pipe
diameter caused by the fouling increases the pressure difference over the equipment.
In order to completely understand the relationship between pressure
difference and deposits such as fouling some basic theory is presented which is
relevant when considering food product g through pipes and conduits of a
sing system such as a dairy.
In a closed system the mass flow m is constant:
m = p1 A1 = p2 A2 [1%], where p is the density of the fluid, 17 is the
velocity of the fluid, and A is the flow area.
If the density p is constant the volume flow V is described by:
V = 171741 = 172 'A2 [mT3]
Bernoulli’s on reads:
p1 =p-g-h1+:i-p+Appump =p-g-h2 +2—22-p+Apf12,Where
p = pressure,
g = gravity,
h = height,
17 = flow velocity,
WO 92414
p = density,
Appump = pressure added from a pump, and
Apflz = pressure losses due to friction.
Apf12 can be calculated from the ing formula, in which A denotes the
pipe on coefficient, Le. a function of Reynolds number and roughness of the solid
surface, E is the single resistance due to valves, bends, etc., and D,- is the inner
diameter of the pipe:
APf12 =2[/1'Dii+25]':—2'P-
If the temperature, density, and the viscosity of the fluid are assumed to be
constant the equation above could be simplified according to the following, which is
valid for the pressure difference in a situation when fluid is ating during cleaning:
Ap = Ksyst - V2, where Ksyst is a constant.
Hence, the pressure difference over a specific process path may be
ined by multiplying a measured volume flow with a predetermined system
constant.
Now referring to Fig. 1, a process scheme describing an indirect UHT (ultra
heat treatment) process system 10 of a milk dairy is shown. The process system 10
includes a number of sections each contributing to the treatment of the milk and further
includes a CIP circuit 100 for cleaning the process system 10.
The milk to be treated is introduced at the left end of the figure, indicated by
the reference “”.A The milk enters a balance tank 101 and is fed by means of a feed
pump 102 to a preheater 103. The heated milk is thereafter transported to a deaerator
104 and a subsequently ed homogenizer 105. Thereafter the milk passes
through a first heater 106 and a second heater 107, whereafter the heated milk is
cooled by a cooler 108 before it exit the processing system at the right end of the
, indicated by reference “”.B A feeding tank 109 for cleaning detergents used for
CIP is further connected to the balancing tank 101.
The first heater 106 forms part of a first g section 110 which is designed
to heat the milk product from approximately 70° to 95°C, wherein a subsequent heating
section 120, including the second heater 107, is designed to heat the milk product from
95° to above 137°C. The choice of heating temperatures of the heating sections 110,
120 is dependent on the particular liquid product processing system, and may be
adjusted according to the d ent of the liquid product. Hence, the above-
mentioned temperatures are examples of one such system.
As is well known within dairy logy the first g section 110 will
mainly induce so called type-A fouling, which is a milk film consisting of 50-70% of
proteins, 30-40% of minerals, and 4-8% of fat. The second heat n 120 will mainly
induce so called type-B fouling, which is a milk stone consisting of imately 15-
% of proteins, 70-80% of minerals, and 4-8% of fat. Generally, fouling occurs mostly
in the heating sections 110, 120 which ns thus are most important to clean.
In a preferred embodiment the first section 110 is provided with two different
pressure sensors 112, 114 arranged at the beginning and at the end, respectively, of
the section 110. The pressure sensors 112, 114 may provide continuous
measurements of the pressure difference over the n 110 during fouling build-up
although their main functionality is to be activated upon CIP initiation for continuous
monitoring of the cleaning process.
pondingly the second section 120 is as well ed with two pressure
sensors 122, 124 arranged at the beginning and at the end, respectively, of the second
section 120. Since the second section 120 is arranged directly after the first section
110 the first sensor 122 of the second section 120 may be the same as the second
sensor 114 of the first n 110. However the sensors 122, 114 may also be
provided as two separate sensors.
The pressure differences across the sections 110, 120 are determined as a
difference between the second sensor 114, 124 and the first sensor 112, 122 of each
section 110, 120. Alternatively, a pressure differential sensor may also be used for the
same purpose.
When ing a CIP process at least five different flow steps may be
considered, which is i) rinsing, ii) dosing of alkaline detergent, iii) ation of alkaline
detergent, iv) dosing of acid detergent, and v) circulation of acid detergent. Typically
these steps are arranged in a sequence and optionally repeated in order to provide
sufficient cleaning of the section.
As Ksyst is dependent on temperature, density, and viscosity of the fluid
flowing through the ent such constant must be determined for all five steps and
for each section. Hence, for two sections 110 and 120 of which each is subject to five
different cleaning steps ten different Ksyst must be known.
The constants are preferably determined by using the equation above for a
section which is considered as clean. By measuring the volume flow and the pressure
difference for each particular cycle in a clean section values of the constant Ksyst are
easily obtained and stored in a reference memory.
When measuring the pressure difference an absolute value is obtained. Since
in most cases a relative value will e sufficient information regarding the cleaning
process a reference value is retrieved ponding to the pressure difference of a
section considered as sufficiently clean.
For this, volume flow sensors (not shown) are provided of which a measured
volume flow is converted to a reference re difference by means of the system
constant Ksyst. According to the a above, the reference pressure difference
equals the square of the actual volume flow multiplied by the system constant. Since
the volume flow is varying, it is preferred to calculate the reference pressure ence
as a function of the measured volume flow. The system constant is determined by
measuring the volume flow and the pressure difference across a clean section,
whereby Ksyst = AVLZ". It is thus necessary to determine the system constant for each
cleaning step since the viscosity and the y of the cleaning agents differ from
each other. When knowing the actual volume flow for a fouled section as well as the
Ksyst for the particular cleaning step the reference pressure difference of a clean
section may be determined.
The ed pressure difference, i.e. the pressure difference determined
directly by subtracting the pressure from the second sensor 114, 124 from the first
sensor 112, 114, is then divided by the reference pressure difference whereby a
pressure difference ratio is calculated. The calculated pressure difference ratio is larger
than 1 for a fouled section, and equals 1 when the cleaning process is finished.
As an example, the following CIP process is determined for cleaning sections
110 and 120 after a specific running time, whereby the treatment of milk during the
running time, including heating of milk, is assumed to have caused fouling within the
pipes of the equipment: i) rinsing, ii) dosing of alkaline detergent, iii) circulation of
alkaline detergent, iv) rinsing, v) dosing of acid ent, vi) ation of acid
detergent, and vii) rinsing.
The pressure difference across the first section 110 is measured continuously
and divided by the calculated reference pressure difference for determining a le
pressure difference ratio. The calculated reference pressure difference is thus a
function of the Ksyst of the particular cycle as well as of the measured volume flow
according to the formula above.
In Fig. 2 the pressure difference ratio of the first section 110 during a CIP
cycle is illustrated as a on of time. The pressure difference ratio is larger than 1 at
the beginning and is kept constant during the g. lnitial rinsing is preferably
performed ly after a purging step, whereby liquid food t still present within
the system is recovered. After the initial rinsing step a uent step is initiated, in
this case introduction of alkaline detergent. When alkaline ent is introduced the
pressure difference ratio increases due to swelling of the fouling in contact with the
alkali after which it is effectively removed during step iii), i.e. circulation of alkaline
detergent. The pressure difference ratio reaches 1, and the following steps of rinsing
and flowing of acid detergent does not contribute to r fouling removal.
The cleaning of type-B fouling, i.e. fouling within the second section 120,
follows another curve which is shown in Fig. 3. Upon introduction of alkaline ent
the pressure ence ratio ses for a short while whereafter it starts to decrease
slowly. The decrease continues as alkaline detergent is circulated in the section 120,
and reaches a steady state which is maintained during a subsequent rinsing step for
ng the alkaline solution from the sections 110, 120. When dosing acid detergent
the fouling starts to dissolve and the pressure difference ratio rapidly ses to 1
during circulation of the acid ent. A final rinsing step is performed in order to
remove all chemicals enclosed within the CIP circuit, which othenNise may affect the
subsequently introduced food product negatively.
The shown example thus represents a CIP process removing all fouling in the
heaters 106, 107 of the dairy system, including the first and second heat sections 110,
120. As the pressure difference ratio is monitored uously, it may be easy to
detect any discrepancies from the normal behaviour of the CIP process, as well as it
provides effective means for optimizing the CIP process.
CIeaning-in-place may be performed on an entire food processing system, i.e.
as shown in Fig. 1 where cleaning detergents are introduced at the milk inlet A for
cleaning all food processing equipments within the system.
However, in other embodiments the entire food sing system may be
divided into two or more CIP circuits, wherein the method of monitoring the CIP
process is implemented for each CIP circuit. Each CIP circuit may further be divided
into two or more subsections, wherein the pressure difference (or pressure difference
ratio) is red continuously for each subsection.
Returning to Fig. 1, measuring the re difference across the first and
second heating sections 110, 120 is advantageous since the CIP process affects the
different sections 110, 120 differently. Consequently, the measured pressure
ences may be used as input for optimizing the CIP process and will provide more
information compared to if a single pressure difference across the heating sections
110, 120 was used.
Preferably, the measured pressure differences are used for optimizing the CIP
process such that the sufficient cleaning is achieved with a m of used time and
ces. The CIP step parameters which may be optimized are preferably detergent
type (i.e. alkaline, acid or water), detergent concentration, detergent flow, duration, and
temperature.
In the ing, a method for pre-optimizing the CIP process will be
described. In a first step, the process system to be cleaned is ted for
determining the sections in which fouling is most likely to occur. This also includes the
step of analyzing the type of food product being treated by the process system, as well
as determining which kind of fouling such product will cause in the different sections.
For example, milk is d to cause type-A fouling in a first heater, and type-B
fouling in a subsequent heater. Further, it is assumed that the rest of the process
system will be sufficiently cleaned if the fouled sections, being ined r, are
As a next step the CIP is defined as a cleaning cycle of different step. The
kind of steps which may be necessary for the CIP process are determined and
normally includes the five steps previously described, i.e. rinsing, dosing of ne
detergent, circulating alkaline detergent, dosing of acid detergent, and ating acid
detergent.
In a next method step reference values are obtained, which references values
include i) the volume flow for each determined section when the section is considered
as clean, i.e. when no or very little fouling is present within the equipment, and ii)
system constants Ksyst for each section and for each CIP cycle.
In order to pre—optimize the entire CIP process each section is ably
investigated individually, whereafter the CIP processes for each section are ed
in order to obtain a complete CIP process for the entire CIP circuit.
When optimizing the cleaning for each section a theoretical approach may be
beneficial, for reducing the number of experiments necessary. For example, it is well
known that type-A fouling is removed efficiently by alkaline detergent, while it is more
resistant to acid detergent. The reverse s for type-B fouling.
However, the zation may also be done by using the pressure sensors
and calculating the re difference across each section during each CIP step.
Hence, a reference table comprising information of how the pressure difference across
a specific section is decreasing as a function of time, temperature, and agent flow may
be determined for each CIP step. It should be noted that the pressure difference
normally does not decrease linearly over time; in most cases the pressure difference
ses rapidly when the cycle starts, while the derivative of the pressure difference
over time thereafter decreases. The reference table may preferably also store
information of the pressure difference ratio, i.e. the measured pressure difference
divided by the pressure difference of a clean section.
2012/075560
The timization of the entire CIP process may be done by deciding the
necessary CIP steps, and in which order they should be performed. For example, it
may be decided that each CIP process should start with a rinse step, and ed by
dosing of alkaline, circulation of ne, rinsing, dosing of acid, ation of acid, and
a final rinsing step. Further details of the process, i.e. CIP step parameters, are
determined as the CIP process is running. Such step parameters may for example be
time, temperature, volume flow, and cleaning agent concentration of each specific CIP
step.
When CIP is initiated, the food product flow is diverted such that no more food
product is introduced into the processing equipment to be clean; i.e. tanks, pipes,
conduits, and other equipment are thus ready to receive cleaning liquids for removing
the fouling. Normally, a rinsing step is performed in which water is fed through the
system at a specific flow, temperature, and time. The pressure ence across the
different sections is monitored continuously and divided with the reference value of a
clean section to form a pressure difference ratio. As the sections are fouled, the
pressure difference will initially be larger than 1. The pre-rinsing step is performed as
long as food t may be recycled from the flow of rinsing water and food product;
whereafter a first rinsing step of the CIP process is initiated. Now referring to Fig. 4, a
food processing system 1000 is shown. The food processing system 1000 receives
food product to be treated at the inlet “”,A and includes two different CIP circuits 100,
200. The first CIP circuit corresponds to the CIP t of the food processing system
shown in Fig. 1, while the second CIP circuit 200 is arranged downstream of the first
CIP t. The treated food product exits the food processing system 1000 at “”,B
after passing the first and second CIP circuits 100, 200.
Starting with the first CIP circuit 100, the CIP inlet tank 109 is ed to
provide cleaning liquid via a feeding pump 102. Cleaning liquid is thus fed through the
food processing equipment 105, such as a homogenizer or any other food processing
equipment, before entering the heaters 106, and 107 respectively. As previously been
described with reference to Fig .1 pressure sensors 112, 114, 122, 124 are arranged to
measure the actual pressure at different ons of the heaters 106 and 107. The
measured values of the pressure are transmitted to a determining unit 130 which
determines the pressure difference across the s 106, 107 by subtracting the
upstream pressure from the ream pressure.
The ined pressure differences for the different heaters 106, 107 are
further itted to a calculator 140, in which the determined pressure differences
are divided by a reference value fetched from a reference memory 150. The reference
value corresponds to the pressure difference of a clean heater, and may be a
measured value or a theoretical value. Further, the reference value may change over
time, such that the reference value is updated according to different operation
parameters of the food processing system, such as e.g. running time, change of liquid
food product, etc. Preferably, a table of reference values are stored in a se.
The calculated pressure difference ratio is thereafter transmitted to a
controller 160, which ller 160 is connected to the CIP inlet tank 109 for
determining the cleaning liquid to be introduced into the CIP circuit, the feeding pump
102 for controlling the volume flow of the particular ng liquid, as well as to the
heaters 106, 107 for controlling the temperature of the cleaning liquid at the respective
heaters 106, 107. Further, the controller 160 is preferably also ured to control the
duration time of a specific cleaning cycle.
As is further shown in Fig. 4, the reference memory 150 may be accessed
from a remote server 300 via internet. The remote server 300 also stores reference
data of optimized ters of different cleaning steps, wherein the controller 160 is
connected to the remote server 300 for ing the ated pressure difference
ratio, as well as for receiving optimized cleaning step ters such as the choice of
cleaning liquid, the volume flow, the temperature, as well as the duration of the
cleaning step. For this purpose an sation algorithm may be ed on the
remote server 300 such that the CIP circuit may be controlled in an efficient way.
As the food product passes the processing equipment 105, 106, 107 included
in the first CIP circuit 100, additional processing equipment 205, 206, 207 is provided
for further treatment of the food product. The equipment 205, 206, 207 may be any
kind of processing equipment used in the food processing industry such as heaters,
coolers, mixers, separators, filters etc. The additional equipment 205, 206, 207 are
enclosed within the second CIP circuit 200, such as the second CIP circuit 200 is
e of cleaning said equipment including the removal of deposits such as g.
For this, the second CIP circuit 200 includes a CIP inlet tank 209 arranged to provide
cleaning liquid via a feeding pump 202. Cleaning liquid is thus fed through the food
processing equipment 205 before entering the additional equipment 206, 207.
Assuming that the ent 206, 207 provides fouling pressure sensors 212, 214,
222, 224 are arranged to measure the pressure before and after each ent 206,
207. The measured values of the pressure are transmitted to a determining unit 230
which determines the pressure difference across the equipments 206, 207 by
subtracting the upstream re from the downstream pressure.
The determined pressure differences are further transmitted to a calculator
240, in which the determined re differences are divided by a reference value
fetched from a reference memory 250. Also for the second CIP circuit, the reference
value corresponds to the pressure ence of a clean equipment. The calculated
pressure difference ratio is thereafter transmitted to a controller 260, which controller
260 is connected to the CIP inlet tank 209 for determining the cleaning liquid to be
introduced into the CIP circuit, the feeding pump 202 for controlling the volume flow of
the particular cleaning liquid, as well as to heaters (not shown) for controlling the
temperature of the cleaning liquid at the respective equipment 206, 207. Further, the
controller 260 is preferably also configured to l the duration time of a specific
cleaning cycle.
The reference memory 250 may be accessed from the remote server 300 via
internet. The remote server 300 also stores reference data of optimized parameters of
different cleaning step, wherein the controller 260 is ted to the remote server
300 for providing the calculated pressure difference ratio, as well as for receiving
optimized cleaning step parameters such as the choice of cleaning liquid, the volume
flow, the temperature, as well as the duration of the cleaning step. For this purpose an
optimisation algorithm may be provided on the remote server 300 such that the CIP
circuit may be controlled in an efficient way.
Although the reference memories 150, 250 have been described as two
separate ents they may be included in a single memory. The same applies for
the controllers 160, 260.
As described above, a method for monitoring fouling of at least one section of
a food processing system has been bed. The method is preferably implemented
for determining a pressure difference ratio by ng an actual pressure ence
with a reference pressure ence, which reference pressure ence is obtained
by multiplying a volume flow through a clean section with a system constant.
A section may be an entire food processing equipment, or a part thereof. For
e, a heater may be divided into several sections, such that a pressure
difference is ed for each section of the heater.
The reference flow meter may r be arranged somewhere in the food
sing system, however it is preferred to arrange the volume flow meter close to a
section across which a pressure difference is measured.
The invention has mainly been described with reference to a few
embodiments. However, as is readily understood by a person skilled in the art, other
embodiments than the ones disclosed above are equally possible within the scope of
the invention, as d by the appended claims.
Claims (30)
1. A method for monitoring the operation of a liquid food processing system, comprising the steps of: 5 initiating a fluid flow through at least one section of said food processing system; determining a pressure ence across said at least one section during said fluid flow for monitoring removal or build-up of ts, said removal or build-up being caused by said fluid flow, and 10 comparing said determined pressure difference with a reference value.
2. The method according to claim 1, further comprising the step of dividing said determined re difference with said reference value for ating a pressure difference ratio.
3. The method according to claim 1 or 2, wherein said reference value represents the pressure difference across said section when said section is considered as being sufficiently clean. 20
4. The method according to any one of claims 1 to 3, wherein said re difference is determined continuously during said fluid flow.
5. The method according to claim 4, wherein said determined pressure difference comprises a value representing the pressure difference derivative, and 25 wherein the method further comprises the step of ing said value with a pressure difference reference derivative.
6. The method according to any one of claims 1 to 5, wherein the pressure difference reference value is calculated by measuring a volume flow of a fluid flow 30 through said section when being sufficiently clean, and multiplying the square of said volume flow with a predetermined constant.
7. The method according to any one of the preceding claims, further comprising dividing said liquid food processing system into at least two sections, 35 wherein said pressure ence is ined across each section during said fluid flow.
8. A method for optimizing the operation of a liquid food processing system, comprising: monitoring said operation according to any one of claims 1 to 7, and stopping said fluid flow when the determined pressure difference equals a 5 predetermined value.
9. The method according to claim 8, wherein said fluid flow is provided by initiating a cleaning step including g a cleaning agent through a cleaning-in-place circuit of said liquid food processing system, wherein the method further comprises the 10 step of changing at least one cleaning step parameter during said cleaning step.
10. The method according to claim 9, wherein said at least one cleaning step parameter is ed from the group consisting of: cleaning step duration, cleaning agent temperature, cleaning agent flow, and cleaning agent concentration.
11. The method according to claim 9 or 10, further sing the step of ting a subsequent cleaning step after stopping the monitored cleaning step.
12. The method according to claim 11, wherein said subsequent ng step 20 is a rinsing step, a dosing of alkaline detergent step, a circulation of alkaline detergent step, a dosing of acid detergent step, or a circulation of acid ent step.
13. The method according to claim 11 or 12, wherein the method of monitoring said ion is repeated for said subsequent cleaning step.
14. The method according to claim 8, wherein said fluid flow is provided by initiating a liquid t flow through said liquid food processing system, n the method further comprises the step of changing at least one product flow parameter during said product flow.
15. The method according to claim 14, further sing the step of initiating a rinsing step after stopping the monitored liquid product flow.
16. The method according to claim 15, further comprising the step of initiating 35 a cleaning-in-place cycle after said rinsing step.
17. The method according to any one of claims 8 to 16, further comprising the step of identifying the t being processed by said liquid food processing system, and wherein said predetermined value of the pressure difference is associated with said product.
18. The method ing to any one of claims 8 to 17, wherein said liquid food processing system is a dairy system.
19. A liquid food processing system comprising 10 at least one section through which liquid food products are flowing during food processing and causing build-up of deposits within said section, and at least one sensor configured to ine a re difference across said at least one section for monitoring removal or up of said deposits, further comprising a calculating unit configured to receive said determined 15 pressure difference and to compare said pressure difference with a reference value.
20. The food sing system according to claim 19, wherein said at least one sensor includes two sensors arranged at a first end and a second end of said section.
21. The food processing system according to claim 19 or 20, further comprising a determining unit connected to said sensors and being configured to calculate said pressure difference. 25
22. The food processing system according to any one of claims 19 to 21, further comprising a cleaning-in-place circuit for ng said deposits by initiating a cleaning cycle including at least one step of flowing cleaning fluid h said at least one section. 30
23. The food processing system according to claim 22, further comprising a controller configured to e said determined pressure difference, wherein said controller is further connected to a pump and/or heating units of said sections and/or a feeding tank for changing the operating parameters of said pump and/or said heating units depending of the received pressure difference.
24. The food processing system according to claim 23, wherein said controller is connected to a remote reference memory storing data representing said operating parameters as a function of pressure difference. 5
25. The food processing plant according to claim 24, wherein said remote reference memory is connected to several food processing systems such that each processing system receives data representing said operating parameters from said reference . 10
26. Kit of parts for installation in a liquid food processing plant, comprising a volume flow sensor for measuring a volume flow of a reference fluid flow, a calculator for determining a reference re difference from said measured volume flow, a pressure difference sensor for measuring a pressure difference of an actual 15 fluid flow, and a controller for comparing said measured pressure difference with said reference re difference for monitoring removal or build-up of deposits during said actual fluid flow. 20
27. A method according to claim 1, ntially as herein described or exemplified.
28. A method according to claim 8, substantially as herein described or exemplified.
29. A liquid food processing system ntially as herein described or exemplified, with reference to the accompanying gs.
30. A kit of parts substantially as herein described or exemplified, with 30 reference to the accompanying drawings. WO 92414 WO 92414
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE1151265 | 2011-12-22 | ||
SE1151265-4 | 2011-12-22 | ||
PCT/EP2012/075560 WO2013092414A1 (en) | 2011-12-22 | 2012-12-14 | A method for monitoring the operation of a liquid food processing system |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ625668A NZ625668A (en) | 2016-01-29 |
NZ625668B2 true NZ625668B2 (en) | 2016-05-03 |
Family
ID=
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