WO2006032731A1

WO2006032731A1 - Method of washing processing apparatus

Info

Publication number: WO2006032731A1
Application number: PCT/FI2005/050323
Authority: WO
Inventors: Heikki Pahlman
Original assignee: Tampereen Teollisuussahko Oy
Current assignee: Tampereen Teollisuussahko Oy
Priority date: 2004-09-22
Filing date: 2005-09-21
Publication date: 2006-03-30
Anticipated expiration: 2007-03-22
Also published as: FI20045350L; FI20045350A0; FI20045350A7

Abstract

The invention relates to a method of washing processing apparatuses used in the processing of foodstuffs, pharmaceuticals or hygiene products. The method comprises washing the processing apparatus (1) and rinsing it with a clean solution, in which case at least one property of the solution that has passed through the processing apparatus is measured and if the measured value is acceptable, the feed of the solution in question into the processing apparatus (1) is stopped and the washing proceeds to the next step.

Description

METHOD OF WASHING PROCESSING APPARATUS

BACKGROUND OF THE INVENTION

[0001] The invention relates to a method of washing processing ap¬ paratuses that process foodstuffs, pharmaceuticals or hygiene products. The method comprises washing the inside of the components belonging to the processing apparatus, such as pipes, containers, etc., using at least one wash¬ ing solution.

[0002] The food industry and the pharmaceutical industry involve a plurality of processes where the material to be processed passes through pipes and containers as well as various other devices during the processing or production. A problem associated with all these is that the processing appara¬ tuses, such as pipes and containers, have to be washed regularly so as to keep the material passing through them sterile and usable. According to the current regulations, processing pipes and apparatuses have to be washed once during an 8-hour shift in dairies, for instance.

[0003] In the food industry, apparatuses are typically washed by emptying pipes, containers and apparatuses of the remaining material by rins¬ ing them with water, after which they are washed with hot water. Then each of them is washed and disinfected with an alkaline washing solution, typically with sodium hydroxide, followed by rinsing with water and then by acid treatment, which neutralizes the alkali and removes crystallizations. After all these steps, the apparatus is rinsed with water.

[0004] Nowadays it is typical of these processes that the same chemicals are continuously recycled from wash to wash. Thus the chemicals used in the washing are returned into the chemical containers from which they were taken for the washing. In that case, the chemicals that have reacted dur¬ ing the wash, such as alkali and acid and the materials mixed with them in the food industry, are also returned into the containers, which means that the reac¬ tion capacity of the chemicals decreases. To provide the chemicals with a suf¬ ficient washing effect, the chemicals are recycled in the apparatuses for long periods, even for hours to obtain a sufficient washing result. Consequently, the apparatus is out of production for a long time, which causes additional costs and reduces the production capacity. Furthermore, the re-use of a dirty wash¬ ing chemical for washing compromises hygiene, regardless of the long wash¬ ing periods. BRIEF DECSRIPTION OF THE INVENTION

[0005] The object of the invention is to provide a method of washing processing apparatuses used in the food industry, pharmaceutical industry and hygiene industry which ensures a higher hygiene standard and a shorter wash¬ ing time. As a result of this, the production capacity of the apparatus increases compared to the existing methods.

[0006] The method according to the invention is characterized in that a clean washing solution is used in each washing step, the washing liquid that has passed though the processing apparatus is discharged from the proc¬ essing apparatus, at least one property of the washing solution that has passed through the processing apparatus is measured continuously, the prop¬ erty having at least one preset limit value which the value measured from the washing solution has to exceed or subceed, depending on the property in question, and that when the values of all measured properties of the washing solution that has passed though the processing apparatus exceed or subceed the limit value defined for the property in question, the feeding of the washing solution into the processing apparatus is stopped and the washing proceeds to the next step.

[0007] The basic idea of the invention is that fresh, clean and active washing fluids are always used in the washing of processing apparatuses. An¬ other basic idea of the invention is that certain properties, such as dirtiness and reactivity, and effectiveness of solutions, in particular chemicals, are measured during the washing. On the basis of the measurements, it can be determined when the washing step of chemicals has been completed suffi¬ ciently well and the washing may proceed to the next step. A further essential aspect of the invention is that the washing fluid used, such as a chemical, for example an acid or alkali, is removed from washing after this wash. An advan¬ tage of the method according to the invention is that it provides a significantly better hygiene standard as the washing is always carried out using fresh and active washing fluid, such as a chemical. Furthermore, only such an amount of chemical that is necessary for washing is used. Furthermore, the required washing time can be reduced significantly because chemicals need not be re¬ cycled as in the prior art to ensure the washing results. The time saved can thus be used for improving the production capacity by the existing apparatus, which increases the production time and the real production capacity of the whole apparatus. DESCRIPTION OF THE FIGURES

[0008] The invention will be described in greater detail in the ac¬ companying drawing, which schematically illustrates a processing apparatus 1 related to the food industry, pharmaceutical industry or hygiene industry. The processing apparatus includes pipes 2, valves 3, containers 4, pumps 5 and various control units 6, as is known in the art. Usually, these pipes 2, valves 3, containers 4 and pumps 5 contain the material to be treated, which is fluid or has a high fluid content, such as milk used in dairies in the food industry. For washing the apparatus, it is provided with containers 7 to 11 for washing chemicals and rinsing fluids or solutions. In this specification and in the claims, fluids and solutions will together be referred to as solutions. Correspondingly, in the claims the term 'wash¹ refers to washing, sterilizing, neutralizing and rins¬ ing, and the term 'washing solution' refers to a washing, sterilizing, neutralizing and rinsing solution.

[0009] For feeding solutions, the processing apparatus is provided with a feed pipe 12, through which the solution to be fed is supplied to the ap¬ paratus to be washed by means of valves 7a to 11a controlling the feed of each solution. After the solution has passed through the apparatus, it is dis¬ charged through a discharge pipe 13. The pipe 13 is provided with one or more measuring devices 14 for measuring one or more properties of the solution. Such measurable properties include dirtiness, i.e. the amount of material not belonging to a clean solution, conductivity, pH, opacity, etc. Furthermore, a spectrum analysis indicating both the reactivity and the dirtiness of the solution may be performed on the solution at the same time. The measurement device may be a single-channel or a multi-channel measurement device and/or an analyzer measuring either one or more properties. As shown schematically by broken line 15, the measurement device is connected to a control unit 16 con¬ trolling the washing process. As shown schematically by broken line 17, the control unit is connected to control valves 7a to 11a, valves 7b to 11b and a three-way valve 18 mounted in the discharge pipe 13. A recovery channel 19 leads from the three-way valve 19 through the valves 7b to 11 b to the respec¬ tive containers 7 to 11 as well as to a waste container 20 illustrated schemati¬ cally, which may be a collector container intended for one or more solutions. There may also be several collection containers.

[0010] When the apparatus 1 is washed, first a rinsing solution is typically fed into it from the container 7 through the valve 7a. In the food indus- try, water is typically used as the rinsing solution for rinsing the remaining ma¬ terial from the apparatus 1. In certain fields, this "bath" consisting of the rinsing solution and the material to be treated may be recovered by supplying it through the three-way valve 18 to the channel 19 and further to the container 8 through the valve 8b. If desired, the material to be treated contained in the bath may be recovered by suitable methods, which are generally known per se.

[0011] When the measurement device 14 indicates that the rinsing solution is clean, the control unit 16 closes the valves 7a and 8b and switches the three-way valve 18 to discharge the solution through the discharge pipe directly into the waste container or into the sewer. After this, washing solution is fed into the apparatus 1 , typically alkali from the container 9 in the food in¬ dustry. This washing solution is fresh and unused, and thus clean and active. The washing solution is fed via the valve 9a through the processing apparatus 1 and the properties of the washing solution exiting the apparatus are meas¬ ured by the measuring device 14 connected to the discharge pipe 13. The washing solution that has passed through the apparatus is discharged from the washing process directly into neutralization or elsewhere, for example into the waste container 20. Certain limit values have been defined for the measured properties of the washing solution. Depending on the measured property, its value has to either exceed or subceed the above-mentioned limit value. For example, when the dirtiness of the washing solution is measured, the value indicating the amount of dirt, i.e. the amount of substances not belonging to the solution, has to subceed a certain limit value and when the reactivity is measured, it has to exceed a set limit value.

[0012] When the measured properties of the washing solution used fulfil certain criteria, for example the solution is sufficiently clean and reactive, the washing with the washing solution is stopped and the washing solution re¬ maining in the processing apparatus 1 can be returned to the chemical cycle. This is carried out in such a manner that the control unit 16 switches the three- way valve 18 to discharge the washing solution from the discharge pipe 13 into the container 9 through the pipe 19 and valve 9b and the processing apparatus is rinsed by supplying rinsing solution, which is for example water in the food industry, from the container 7 into the apparatus 1 through the valve 7a. If an¬ other rinsing solution is required, it may be stored in container 10, for example, from which the solution is fed into the apparatus through the valve 10a. When the values measured by the measuring device 14 indicate that the processing apparatus is running out of washing solution, the control unit prevents the flow of the solution to the container 9 through the pipe 19 and makes the rinsing solution flow either into the sewer or waste container 20. After rinsing, another washing solution may be fed into the processing apparatus, such as a solution that neutralizes the remains of the previous washing solution, for example acid from container 11. If necessary, the clean solution that is inside the processing apparatus may be recovered in accordance with the steps described above, in which case the properties of the solution are measured in the discharge pipe 13 leading out of the processing apparatus 1. This washing solution, such as neutralizing acid, is also supplied either to neutralization or the waste container after the processing, and neutralization continues until the measured proper¬ ties of the solution fulfil the pre-set criteria. After the washes, the processing apparatus is naturally rinsed again, after which it is hygienic and ready for re¬ use. In addition, it has been washed in a time shorter than the current washing times. If necessary, new solutions may be fed into the different containers through the pipe 21 and valve 22 as well as through the valves 7b to 11b, which provide a connection to each container, either one container at a time or to each container through separate pipes in a manner known per se.

[0013] Depending on the size of the processing apparatus, dozens of minutes may be saved in one wash compared to the washing times of a normal processing apparatus. For example, in a plant with ten process lines that have to be washed three times a day, even 30 x 30 minutes = 15 hours can be saved, for instance.

[0014] The invention was described by an example in connection with the food industry, where an alkali, usually sodium hydroxide, is typically used as the washing agent and a weak acid for neutralizing the alkali. Instead of acid, other chemicals may also be used in the neutralization, such as chlo¬ rine, etc. The solution according to the invention is, however, similarly applica¬ ble to the pharmaceutical industry or hygiene industry where various products are manufactures, such as pharmaceuticals. Naturally, various suitable wash¬ ing and neutralizing solutions may be employed in these industries, including sodium boron hydride, trimethyl borate, ammonium, chlorine compounds, hy¬ drogen-based solutions, such as hydrogen peroxide, alcohols, etc. What is essential is that the basic idea of this invention is applied, i.e. the fact that the washing chemical and the neutralizing chemical are always clean and active chemical solutions which, after passing through the process, are discharged without recycling them into the process. Furthermore, one or more properties of the washing solution that has passed through the process are measured so that when the properties fulfil preset criteria, the ongoing washing step or neu¬ tralizing step is stopped and the process proceeds to the following step, typi¬ cally to rinsing. In addition, the invention can be used in the same way for monitoring the rinsing solution.

Claims

1. A method of washing processing apparatuses used in treating foodstuffs, pharmaceuticals or hygiene products, the method comprising wash¬ ing the inside of the components belonging to the processing apparatus, such as pipes, containers, etc., using at least one washing solution, character¬ ized in that a clean washing solution is used in each washing step, the wash¬ ing solution that has passed through the processing apparatus is discharged from the processing apparatus, at least one property of the washing solution that has passed through the processing apparatus is measured continuously, the property having at least one preset limit value which the value measured from the washing solution has to exceed or subceed, depending on the prop¬ erty in question, and that when all measured values of the washing solution that has passed through the processing apparatus exceed or subceed that limit value defined for the property in question, the feed of washing solution into the processing apparatus is stopped and the washing proceeds to the next wash¬ ing step.

2. A method according to claim 1 , characterized in that the washing is carried out using at least two different washing solutions.

3. A method according to claim 1 or 2, characterized in that at least one washing solution is a reactive washing solution and that at least the reactivity of the washing solution that has passed through the processing ap¬ paratus is measured.

4. A method according to any one of claims 1 to 3, character¬ ized in that at least the dirtiness of the washing solution that has passed through the processing apparatus is measured.

5. A method according to any one of the preceding claims, char¬ acterized in that at least a spectrum analysis is performed on the washing solution that has passed through the processing apparatus.

6. A method according to any one of the preceding claims, char¬ acterized in that at least the opacity of the washing solution that has passed through the processing apparatus is measured.

7. A method according to any one of the preceding claims, char¬ acterized in that at least the conductivity of the washing solution that has passed through the processing apparatus is measured.

8. A method according to any one of the preceding claims, char¬ acterized in that at least the pH of the washing solution that has passed through the processing apparatus is measured.

9. A method according to any one of the preceding claims, char¬ acterized in that at least one of the measurements is performed by optical measurement devices.

10. A method according to any one of the preceding claims, char¬ acterized in that at least one of the measurements is performed by an ana¬ lyzer that takes samples.

11. A method according to any one of the preceding claims, char¬ acterized in that if even one value measured from the washing solution that has passed through the processing apparatus exceeds or subceeds the limit value set for it, the solution is discharged from the processing device and cor¬ respondingly, if all the values measured from the washing solution that has passed through the processing apparatus are acceptable within the set limit values, in which case the washing solution is substantially clean and unre- acted, the washing solution remaining in the processing apparatus is recov¬ ered.

12. A method according to any one of the preceding claims, char¬ acterized in that alkali is used as the washing solution and acid is used as its neutralizing solution and these are mixed with each other after the washing step to neutralize them.