JP4835944B2 - Cleaning time calculation method, parameter value calculation method, and cleaning design support method during pipe cleaning - Google Patents

Description

  The present invention relates to a method for calculating a cleaning time at the time of pipe cleaning, a method for calculating a parameter value other than the cleaning time, and a cleaning design support method for calculating the cleaning performance of a pipe designed using these methods. In particular, the present invention relates to a method suitable for selecting a cleaning condition set in a cleaning device when fixedly cleaning equipment piping used in a manufacturing process of food, medicine, and the like.

  In the process of manufacturing liquid products, especially in manufacturing plants for foods and pharmaceuticals, the piping after the product is transferred is cleaned at each process or periodically to prevent microbial contamination and adhesion of unnecessary components. ing. The cleaning of piping is examined according to the type of dirt, the purpose of cleaning, etc., and the method is taken into consideration so that chemical cleaning and sterilization are performed and proper hygiene management is performed. The term “dirt” as used herein refers to what remains after the product is transferred or is present at an illegal place, and does not indicate only a contaminant.

  Here, the relationship between the contamination of piping and cleaning conditions is qualitatively known. For example, in a cleaning experiment by Jennings, it has been reported that the Reynolds number is about 50,000 or more as a condition for removing dirt. However, since the relationship between the contamination of the piping and the cleaning conditions is not quantitatively clear, the cleaning conditions have been determined empirically. In recent years, the cleaning of piping in the manufacturing process is often performed by so-called in-place cleaning (CIP) rather than disassembly cleaning. For this reason, when the cleaning conditions such as the cleaning time and the cleaning liquid are determined based on the experience of the operator, the safety is taken into consideration, the condition setting becomes excessive, and the residual rate of dirt also varies. There was a problem that would occur.

In view of such a situation, various cleaning apparatuses and methods for automatically performing stationary cleaning of pipes have been proposed. For example, techniques disclosed in Patent Document 1 and Patent Document 2 can be cited. Here, the technique disclosed in Patent Document 1 is a technique for washing away the cleaning liquid with the rinsing liquid after the cleaning with the cleaning liquid, and relates to preventing waste of the rinsing liquid and remaining of the cleaning liquid. is there. And the technique currently disclosed by patent document 2 is related with the technique of making the washing | cleaning liquid after use harmless to a human body etc., and saving the effort of the rinse after washing | cleaning.
JP 2001-161264 A JP 2005-52803 A

  By using techniques such as those disclosed in Patent Documents 1 and 2, it is considered that it is possible to carry out cleaning without variation quantitatively. However, each of the above techniques has a problem in that a plurality of sensors are provided on the piping to be cleaned, and the cleaning time and the remaining rate of dirt cannot be grasped unless the cleaning is actually performed. It was. For this reason, when piping must be cleaned within a limited time, parameters such as the concentration, flow rate, and temperature of the cleaning solution must be excessive. In addition, since it is not possible to know the cleanability unless the actual cleaning is performed, it was not possible to select whether or not to select a cleaning device unless the facility was completed.

  Therefore, in the present invention, based on an arbitrary selection value for one parameter selected from a plurality of parameters required for cleaning a given piping structure, and other parameters set as known values. In addition, the present invention provides a cleaning time calculation method and a parameter value calculation method in pipe cleaning that can obtain an unknown parameter required to obtain a selected value for the parameter 1, and uses these calculation methods. An object of the present invention is to provide a cleaning design support method that enables prediction of cleaning performance at the design stage of the piping structure.

数式５に対して前記洗浄剤の流速、温度、濃度を代入すると共に前記洗浄係数と前記洗浄剤の流速、温度、濃度との関係により予め求められた各パラメータのそれぞれを底とする洗浄係数の対数Ａ１からＡ３、および入力値に対して一義的に定められる補正値Ａ０、Ａ４を代入して洗浄係数を算出する工程と、算出された洗浄係数により、洗浄前の配管に存在する汚れに対する洗浄後に配管に残存する汚れの割合として表される相対残存率を除算して、目標とする洗浄効果を得るために必要とされる洗浄時間を算出する工程とを有することを特徴とする。 The method for calculating the cleaning time in pipe cleaning according to the present invention for achieving the above object is to pour a cleaning agent into the pipe, and to clean the dirt adhering to the inside of the pipe by the action of the flowing cleaning agent. Is a method for calculating the cleaning time required to obtain the cleaning effect, and formula 5 is calculated to obtain a cleaning coefficient indicating the cleaning efficiency of the pipe,

Substituting the flow rate, temperature, and concentration of the cleaning agent into Equation 5 and the cleaning coefficient based on each parameter determined in advance by the relationship between the cleaning coefficient and the flow rate, temperature, and concentration of the cleaning agent. A process of calculating a cleaning coefficient by substituting logarithm A1 to A3 and correction values A0 and A4 that are uniquely determined for the input value, and cleaning the dirt existing in the pipe before cleaning by the calculated cleaning coefficient And a step of calculating a cleaning time required to obtain a target cleaning effect by dividing a relative residual ratio expressed as a ratio of dirt remaining in the pipe later.

前記洗浄剤の流速、温度、濃度のうちから選択されなかった１つのパラメータの値を算出する工程とを有することを特徴とする。 In addition, the parameter value calculation method in the pipe cleaning according to the present invention for achieving the above-described object is provided when a cleaning agent is poured into the piping and the dirt adhered to the inside of the piping is washed by the action of the flowing cleaning agent. This is a method for calculating the parameter value of the cleaning agent necessary for obtaining the target cleaning effect at a predetermined time, and cleaning the dirt existing in the pipe before cleaning by the value given as the cleaning time. A step of obtaining a cleaning coefficient obtained by dividing a relative residual ratio expressed as a percentage of dirt remaining in the piping later, and substituting this cleaning coefficient into Equation 6 and selecting from the flow rate, temperature, and concentration of the cleaning agent And the cleaning coefficient based on each of the parameters determined in advance by the relationship between the flow rate, temperature and concentration of the cleaning agent and the cleaning coefficient. Several A1 A3, and is uniquely determined for the input value by substituting the correction value A0, A4,

And calculating a value of one parameter not selected from the flow rate, temperature, and concentration of the cleaning agent.

数式７に対して前記洗浄剤の流速、温度、濃度を代入すると共に前記洗浄係数と前記洗浄剤の流速、温度、濃度との関係により予め求められた各パラメータのそれぞれを底とする洗浄係数の対数Ａ１からＡ３、および入力値に対して一義的に定められる補正値Ａ０、Ａ４を代入して洗浄係数を算出する工程と、算出された洗浄係数により、洗浄前に洗浄性予測対象とする箇所に存在する汚れに対する洗浄後に洗浄性予測対象とする箇所に残存する汚れの割合として表される相対残存率を除算して、目標とする洗浄効果を得るために必要とされる洗浄時間を算出する工程とから成ることを特徴とする。 Further, the cleaning design support method according to the present invention for achieving the above object includes a step of modeling a piping structure to be cleaned, and a flow velocity distribution when a cleaning agent is caused to flow into the modeled piping structure. A step of obtaining, a step of extracting a flow velocity of a portion to be a detergency prediction target in the piping structure, and formula 7 for obtaining a cleaning coefficient indicating a cleaning efficiency of the portion to be the detergency prediction target,

Substituting the flow rate, temperature, and concentration of the cleaning agent into Equation 7 and the cleaning coefficient based on each parameter determined in advance by the relationship between the cleaning coefficient and the flow rate, temperature, and concentration of the cleaning agent. A step of calculating a cleaning coefficient by substituting logarithm A1 to A3 and correction values A0 and A4 that are uniquely determined for the input value, and a place to be subjected to cleaning performance prediction before cleaning by the calculated cleaning coefficient The cleaning time required to obtain the target cleaning effect is calculated by dividing the relative residual rate expressed as the ratio of the soil remaining in the location where the cleaning performance is to be predicted after cleaning the soil existing in It consists of a process.

前記洗浄剤の温度、濃度のうちから選択しなかった他方のパラメータの値を算出する工程とを有することを特徴とするものであっても良い。 The cleaning design support method according to the present invention includes a step of modeling a piping structure to be cleaned, a step of obtaining a flow velocity distribution when a cleaning agent is introduced into the modeled piping structure, and the piping structure. In the step, the flow rate of the portion to be predicted for cleaning is extracted and the value given as the cleaning time for the portion to be cleaned is predicted to clean the dirt existing in the portion to be predicted for cleaning. A step of obtaining a cleaning coefficient obtained by dividing a relative residual ratio expressed as a percentage of dirt to be predicted for cleaning performance later, and substituting this cleaning coefficient and the extracted flow rate into Equation 8 and the temperature of the cleaning agent, Each of the parameters determined in advance by the relationship between one of the parameters of the concentration and the flow rate, temperature and concentration of the cleaning agent and the cleaning coefficient From the logarithmic A1 washing coefficients A3, and substituting the correction value A0, A4, which is uniquely determined for the input value,

And a step of calculating a value of the other parameter not selected from the temperature and concentration of the cleaning agent.

  According to the method for calculating the cleaning time in pipe cleaning as described above, the cleaning time required for obtaining the desired cleaning effect can be easily calculated based on the parameters of the cleaning agent selected as the cleaning agent used for pipe cleaning. It can be carried out. Further, according to the parameter value calculation method in the pipe cleaning as described above, another parameter value is calculated based on any two parameter values selected from the cleaning time and the flow rate, temperature, and concentration of the cleaning agent. Can be calculated.

  In addition, according to the cleaning design support method as described above, the flow rate of the detergent flowing through the detergency predicted portion is derived by simulation, and the cleaning time is calculated using this flow rate as one of the parameters at the time of piping cleaning. It is possible to calculate the time until the cleaning of the details (for example, the branch pipe) is completed at the design stage. Moreover, when determining the temperature or concentration in the cleaning agent based on the predetermined cleaning time and the flow rate derived from the simulation, depending on the flow rate of the cleaning agent discharged by a pump or the like set in the design stage, It is possible to calculate the parameter value of the cleaning agent required to finish the cleaning within the set time.

  Hereinafter, embodiments according to the present invention relating to a cleaning time calculation method, a parameter value calculation method, and a cleaning design support method will be described in detail with reference to the drawings.

  First, a system configuration for carrying out the cleaning design support method of the present invention will be described with reference to FIG.

  The cleaning design support method according to the present embodiment makes it possible to predict the cleaning performance on a monitor 24 such as a personal computer (hereinafter referred to as a PC) 10 without providing an actual machine. For this reason, the system configuration basically includes, for example, a main body 12 constituting the PC 10, a monitor 24, and input means 30 such as a keyboard 26 and a mouse 28.

  The main body 12 includes at least a CPU (Central Processing Unit) 14, a hard disk 18, a main memory 16, a display memory 20, an interface 22, and the like as constituent elements. These components are connected to each other via a bus so that various data can be transferred between the components.

  The CPU 14 is an arithmetic means for controlling a program stored in the hard disk 18, the main memory 16, the display memory 20, etc., which will be described in detail later, and calculating and processing data. That is, data stored in the hard disk 18 or the main memory 16 is received, calculated and processed, and then output to the monitor 24 or written again to the hard disk 18 or the like.

  The hard disk 18 is one of storage means, and is composed of a disk coated with a magnetic material and a magnetic head, and is generally used for storing a program or data having a large capacity. In the case of this embodiment, basic software such as design software such as CAD, other drawing software, fluid analysis software that can be linked to the model drawn by the design software or drawing software, and simulation software that can integrate these software In addition, various experimental data acquired using an experimental model, machining data using the data, and the like may be stored.

  The main memory 16 is also one of storage means. A difference from external storage means such as the hard disk 18 is that a semiconductor element is used as a component. Since an electrical method is employed as a recording method, data can be read and written at high speed, and can be directly executed by the CPU 14. For this reason, in general, it is often used to store a basic program for operating the PC 10 and primary data.

  The display memory 20 is a memory that plays an auxiliary role of the main memory 16, and in the case of this embodiment, the arrangement and order of image data and numerical data to be displayed on the monitor 24 as display means are temporarily stored. It can be set as a memory means for memorizing.

  In the case of this embodiment, the interface 22 is a hardware interface that mediates the exchange of information between the main body 12 in the PC 10, the monitor 24 as the display means, and the keyboard 26 and mouse 28 as the input means 30. Shall be shown.

  Next, a method for predicting detergency in pipe cleaning using the system (PC 10) configured as described above (calculation of cleaning time, parameter value of cleaning agent) will be described.

  In the system as described above, first, modeling of a place where the cleaning performance of the constructed pipe is predicted is performed. For modeling the predicted washing location, CAD software or the like stored in the hard disk 18 may be started and used to draw a new drawing, or it may be used when design drawings relating to the piping configuration are stored. Then, the corresponding part may be extracted. FIG. 2 shows a model of a flow path having a main pipe and a branch pipe connected to the main pipe.

  After completion of modeling of the predicted washing location, software for performing simulation according to the design model, such as fluid analysis software, is started. The simulation software includes a primary parameter group input thread 54 and a secondary parameter group input thread 56 as shown in FIG. 4, and a secondary parameter group is obtained by simulation based on the contents input to the primary parameter group input thread 54. It is preferable that the parameters to be input to the input thread 56 are derived. By adopting such a configuration of the simulation software, it becomes possible to perform feedback analysis according to the data obtained based on the simulation, and the flow velocity inside the branch pipe 52 that cannot be known at the initial stage of the cleaning performance prediction This is because it can be obtained without experimenting.

  In the primary parameter group input thread 54, the flow rate of the cleaning agent in the flow path of the main pipe 50 (main pipe flow rate), the temperature of the cleaning agent (cleaning temperature), the type of cleaning agent (cleaning agent), the cleaning, which can be known as one of information. Input items such as the concentration of the cleaning agent (cleaning agent concentration) and the type of dirt to be cleaned (target dirt type) are provided.

  Then, the secondary parameter group input thread 56 includes an average flow velocity (predicted portion average flow velocity) of the predictability of detergency that can be derived by simulation after the input of the primary parameter group input thread 54, and the vicinity of the pipe wall surface at the predictability of detergency. In addition to input items such as the flow rate (predicted portion shear force) and the cleaning efficiency (cleaning coefficient) at the predicted detergency location, input items for determining a desired cleaning time may be provided. In the form shown in FIG. 4, the average flow velocity and the shear force are distinguished and used as input items. However, since the flow velocity distribution inside the branch pipe 52 is complicated, only the average flow velocity may be used as the input item. good.

ここで、Ｋは洗浄係数、ｔは洗浄時間、Ｒは汚れの相対残存率、Ｄ_０は洗浄前に存在する汚れ、Ｄは洗浄後に残存する汚れを示す。つまり、洗浄係数Ｋを算出するには、相対残存率Ｒを洗浄時間ｔで除算すれば良い。 The cleaning coefficient can be determined from the cleaning result and the time required for cleaning. The relationship between changes in parameter values such as the flow rate, temperature, and concentration of the cleaning agent used for cleaning and changes in the cleaning coefficient is determined in advance. Therefore, it is possible to calculate based on the value of each parameter. For example, when the cleaning coefficient is derived based on the experimental value, Equation 9 may be used.

Here, K is a cleaning coefficient, t is a cleaning time, R is a relative residual rate of dirt, D ₀ is dirt existing before cleaning, and D is dirt remaining after cleaning. That is, in order to calculate the cleaning coefficient K, the relative remaining rate R may be divided by the cleaning time t.

ここで、Ｖは洗浄剤の流速（せん断力）、Ｔは洗浄剤の温度、Ｃは洗浄剤のアルカリ濃度（濃度）を示し、Ａ１からＡ３は実験により求まる対数であり、Ａ０、Ａ４は、計算により算出される洗浄係数Ｋと、実験値に基づいて定められる洗浄係数Ｋとを比較した場合における補正値である。 On the other hand, when the cleaning coefficient K is derived from parameter values such as the flow rate, temperature, and concentration of the cleaning agent, Formula 10 may be used.

Here, V is the flow rate (shearing force) of the cleaning agent, T is the temperature of the cleaning agent, C is the alkali concentration (concentration) of the cleaning agent, A1 to A3 are logarithms obtained by experiments, and A0 and A4 are This is a correction value when the cleaning coefficient K calculated by calculation is compared with the cleaning coefficient K determined based on experimental values.

A1 to A3 will be described in detail. As shown in FIGS. 7 to 9, the amount of change in the flow rate, temperature, and concentration and the amount of change in the cleaning coefficient K are derived by experiments, and this is an exponential function related to K. As a logarithm of the cleaning coefficient K with each parameter as a base. Further, A0 and A4 will be described in detail. An error between the two values generated when comparing the value of K ′ derived from Equation 11 with K in the experimental value in which each parameter is assigned to the numerical value assigned to Equation 11 is compared. It is a value for correction (A0 is a correction value of a multiplier term, A4 is a correction value of an addend term), and may be uniquely determined for each type of cleaning agent, for example.

  In this way, by storing each data in a database and storing it in the hard disk 18 or the like so that the cleaning coefficient K can be derived from experimental values and calculated values, the parameters of the cleaning agent for Equation 10 are stored. In addition to calculating the cleaning time required for cleaning from the input of the value, it is also possible to calculate the parameter value of the cleaning agent from the input of the cleaning time.

  In other words, when the cleaning coefficient K is calculated by Equation 10, the calculated value is substituted for K in Equation 9, and a desired value is input as the relative residual rate R of dirt, so that the desired parameter value is set. A cleaning time t for obtaining a cleaning result can be calculated. On the other hand, when the relative remaining rate R and the cleaning time t for obtaining the cleaning result are determined in advance, the cleaning coefficient K can be derived on the basis of Equation 9. Thereafter, when it is desired to obtain a parameter value other than the parameter value to be calculated from among the parameter values in the cleaning agent, for example, the flow velocity V, the flow velocity V can be calculated by inputting the temperature T and the concentration C into Equation 10. it can.

  Results such as the calculated cleaning time may be stored in a database for each cleaning pattern and displayed in a database so as to be visible as shown in FIG.

  Hereinafter, a flow when the cleaning design support method of the present invention is implemented using the above system will be described with reference to FIG.

  First, the design software or the like is activated to model the detergency predicted portion (step 110: (see FIG. 2)). Next, the fluid analysis and simulation software is activated, and input items in the primary parameter group input thread 54 are input (step 110 (see FIG. 4)). After completing the input of the primary parameters, the flow velocity vector inside the modeled pipe is output by executing the simulation (steps 120 to 140: (see FIG. 3)). The cleaning coefficient K is calculated by substituting the flow velocity (average flow velocity or shear force) of the predicted detergency derived by the simulation into Equation 10 (step 150). The calculated cleaning coefficient K is output to the monitor 24 (step 160). Thereafter, based on the calculated cleaning coefficient K, the cleaning time for the predicted cleaning property is calculated based on Equation 9 (step 170). Thereafter, the cleaning time t is displayed on the display means such as the monitor 24 as a numerical value that can be read visually (step 180).

  After the output of the cleaning time is completed, if there is a model change at a location where the cleaning performance is predicted, the process returns to step 100 and the cleaning time is calculated. On the other hand, if there is no model change, the process ends (step 190).

  In the above-described embodiment, it is described that the cleaning coefficient K and the cleaning time t are calculated by modeling the predictability of the cleaning property, inputting the primary parameter, and obtaining the secondary parameter by simulation. However, after modeling, the secondary parameter cleaning coefficient K and cleaning time t are given, and the temperature T and concentration C of the cleaning agent are input to calculate the flow velocity V required for the predicted detergency point. The main pipe flow velocity may be derived. Note that the temperature T and the concentration C of the cleaning agent are not changed between the main pipe 50 and the branch pipe 52, and therefore can be calculated based on Expression 10 even when simulation is not performed.

  By implementing the cleaning design support method as described above, it is possible to predict the cleaning performance at the design stage of the piping structure, making it easy to select pumps and cleaning agents to be used for piping cleaning. can do.

It is a flowchart which shows the flow at the time of implementing the washing | cleaning design support method which concerns on this invention. It is a figure which shows the modeling example of the piping model by design software etc. It is a figure which shows the example of the fluid analysis with respect to the modeled model. It is a figure which shows an example of the parameter input screen at the time of performing the washing | cleaning property prediction of a piping path | route. It is a figure which shows the example of the graph displayed based on several data which estimated the washability. It is a figure which shows the structural example of the system utilized when enforcing a line design support method. It is a graph which shows the relationship between the variation | change_quantity of the flow rate in a cleaning agent, and the variation | change_quantity of a washing | cleaning coefficient. It is a graph which shows the relationship between the variation | change_quantity of the temperature in a cleaning agent, and the variation | change_quantity of a washing | cleaning coefficient. It is a graph which shows the relationship between the variation | change_quantity of the density | concentration in a cleaning agent, and the variation | change_quantity of a cleaning coefficient.

Explanation of symbols

  10 ......... PC, 12 ......... Main body, 14 ......... CPU, 16 ......... Main memory, 18 ......... Hard disk, 20 ...... Display memory, 22 ......... Interface, 24 ......... Monitor, 26 ......... Keyboard, 28 ......... Mouse, 30 ......... Input means, 50 ......... Main pipe, 52 ......... Branch pipe, 54 ......... Primary parameter group input thread, 56 ......... Secondary parameter group Input thread.

Claims (4)

This is a method for calculating a cleaning time required to obtain a target cleaning effect when a cleaning agent is poured into a pipe and the dirt adhered inside the pipe is washed by the action of the poured cleaning agent. And
Formula 1 for obtaining a cleaning coefficient indicating the cleaning efficiency of the pipe is established,

Substituting the flow rate, temperature, and concentration of the cleaning agent into Equation 1 and the cleaning coefficient based on each parameter determined in advance by the relationship between the cleaning coefficient and the flow rate, temperature, and concentration of the cleaning agent. Calculating a cleaning coefficient by substituting correction values A0 and A4 that are uniquely determined for logarithms A1 to A3 and input values;
Necessary to obtain the target cleaning effect by dividing the relative residual rate expressed as the ratio of dirt remaining in the pipe after cleaning to the dirt existing in the pipe before cleaning by the calculated cleaning coefficient A method for calculating a cleaning time at the time of pipe cleaning. The parameters of the cleaning agent that are required to obtain the target cleaning effect in a predetermined time when the cleaning agent is poured into the piping and the dirt adhered inside the piping is cleaned by the action of the flowing cleaning agent. A method of calculating a value,
A step of obtaining a cleaning coefficient obtained by dividing a relative residual ratio expressed as a ratio of dirt remaining in the pipe after cleaning with respect to dirt existing in the pipe before cleaning by a value given as the cleaning time;
Substituting this cleaning coefficient into Equation 2 and two parameters selected from the flow rate, temperature, and concentration of the cleaning agent, and the relationship between the cleaning coefficient, the flow rate, temperature, and concentration of the cleaning agent were determined in advance. Substituting logarithm A1 to A3 of the cleaning coefficient with each parameter as the base and correction values A0 and A4 that are uniquely defined for the input value,

And a step of calculating a value of one parameter not selected from the flow rate, temperature, and concentration of the cleaning agent. A process for modeling the piping structure to be cleaned;
A step of obtaining a flow velocity distribution when a cleaning agent is introduced into the modeled piping structure;
A step of extracting a flow velocity at a place to be a detergency prediction target in the piping structure;
Formula 3 is calculated to obtain a cleaning coefficient indicating the cleaning efficiency of the portion to be predicted for cleaning.

Substituting the flow rate, temperature, and concentration of the cleaning agent into Equation 3 and the cleaning coefficient based on each parameter determined in advance by the relationship between the cleaning coefficient and the flow rate, temperature, and concentration of the cleaning agent. Calculating a cleaning coefficient by substituting correction values A0 and A4 that are uniquely determined for logarithms A1 to A3 and input values;
Divide by the calculated cleaning coefficient the relative residual rate expressed as the percentage of dirt remaining in the location subject to cleaning predictability after cleaning against the soil present in the location subject to cleaning predictability before cleaning And a step of calculating a cleaning time required to obtain the cleaning effect as described above. A process for modeling the piping structure to be cleaned;
A step of obtaining a flow velocity distribution when a cleaning agent is introduced into the modeled piping structure;
A step of extracting a flow velocity at a place to be a detergency prediction target in the piping structure;
Relative residual expressed as a ratio of dirt to be cleaned predictable after cleaning with respect to dirt existing in the spot to be cleaned before cleaning, by a value given as a cleaning time of the spot to be predicted to be cleaned Obtaining a cleaning coefficient obtained by dividing the rate;
The cleaning coefficient and the extracted flow rate are substituted into Equation 4 and determined in advance by one of the parameters of the cleaning agent temperature and concentration, and the relationship between the cleaning agent flow rate, temperature and concentration and the cleaning factor. Substituting the logarithm A1 to A3 of the cleaning coefficient based on each of the parameters, and correction values A0 and A4 that are uniquely determined for the input value,

And a step of calculating a value of the other parameter not selected from the temperature and concentration of the cleaning agent.

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