JP2000246196A - Washing method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce rinsing time and the used quantity of rinsing water while complete washing can be performed by injecting gaseous CO2 and/or carbonated water to water used in a rinsing process. SOLUTION: In a washing method in which water and acidic, alkaline detergents are alternately fed and pre-washing, washing, and rinsing processes are performed in this order, a device for injecting gaseous CO2 and/or carbonated water into water used in the rinsing process is arranged. This device is provided with pH meters 1 and 2, a gaseous CO2 cylinder, a line mixer, a liquid transfer pump, and a heat exchanger. The pH meter 1 is installed at a waste water outlet of a washing object device shown as a production line to check pH of waste water, and for example, if pH becomes 8-9.5, the termination of washing is detected to stop the injection of gaseous CO2 by control equipment. The pH meter 2 monitors the variations in pH of water into which gaseous CO2 is injected to agitate and mix them by a line mixer and into which gaseous CO2 is blow and checks its abnormality occurrence (such as, the gaseous CO2 cylinder becoming empty).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning method applicable to the cleaning of various instruments and devices which require strict cleaning in the field of food and medical products.

[0002]

2. Description of the Related Art In various devices and devices used in the manufacturing process of liquid foods and medical products, the contents of the flow passages inside and outside the device are discharged after the use of these devices and devices is completed, or when a manufacturing item is changed. Then, if necessary, an acidic detergent is passed through these flow paths for washing, and then an alkaline detergent is passed through the flow path for washing (each detergent is collected in the detergent tank after washing is completed). Rinsing is performed by passing water through to remove detergent remaining in the road.

[0003] This rinsing step is performed for the purpose of removing residual detergent, and the rinsing water used at that time is neutral water having a pH of about 7, so-called "fresh water" (mizu). The cleaning is performed until the pH of the rinsing water (drainage) used for washing becomes neutral around 7, or until the electric conductivity of the rinsing water becomes the same level as the electric conductivity of the rinsing raw water.

[0004] However, such a rinsing process has the disadvantage that the required time is long and the amount of raw water required for rinsing is enormous. In particular, in recent years, the frequency of stationary cleaning has increased to meet the demand for high-mix low-volume production due to diversifying needs, or to meet economic demands such as inventory optimization, which directly contributes to production. The length of non-rinsing time greatly reduces production efficiency.

[0005] In addition, an increase in rinsing wastewater results in an increase in production cost and an increase in load on wastewater treatment equipment.
In addition, these increases must be prevented from the viewpoint of protection of water resources, and the reduction in the amount of rinsing water has been strongly demanded by the industry.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, that is, a drastic reduction in rinsing time and rinsing water consumption while allowing for thorough cleaning. An object of the present invention is to provide a cleaning method that enables the cleaning.

[0007]

According to a first aspect of the present invention, there is provided a cleaning method comprising the steps of: washing with an alkaline detergent; rinsing the detergent with water; This is a cleaning method having a drop rinsing step in this order, in which carbon dioxide gas and / or carbonated water is injected into water used in the rinsing step.

In the cleaning apparatus according to the present invention, a detergent supply means for supplying an alkaline detergent to the equipment to be cleaned, and a carbon dioxide for supplying water into which carbon dioxide gas and / or carbonated water has been injected. It is a washing device provided with water supply means.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] The alkaline detergent (hereinafter also referred to as "alkaline detergent") which can be used in the present invention is sodium hydroxide or sodium hydroxide as a main component which is generally used widely and various surfactants are added thereto. And a detergent dissolved in water.

A pre-cleaning step may be provided before the cleaning step using an alkaline detergent. That is, for example, by pre-washing the system to be cleaned using an acidic or neutral detergent (pre-washing step), dirt components that are easily removed under acidic or neutral conditions are removed in advance, and then an alkaline detergent is used. Performing the cleaning step enables more complete cleaning. However, even in these steps, it is necessary to use a detergent having a standard suitable for the application at an appropriate concentration.

In the washing method of the present invention, all water used in the process must be clear and suitable for each use. In the cleaning method of the present invention, in the rinsing step, it is necessary to use water into which carbon dioxide gas and / or carbonated water has been injected with respect to the appropriate water as described above.

When injecting carbon dioxide gas, the carbon dioxide gas can be continuously injected by blowing the carbon dioxide gas into the flow path of the water and mixing the mixture by a mixing means such as a static mixer on the downstream side. In addition, by adding carbon dioxide gas to the water to which carbon dioxide gas has been injected in advance, that is, to the water that can be used for washing, water to which carbonated water has been injected can be obtained.

In the present invention, it is necessary to use carbon dioxide (carbon dioxide). Carbon dioxide is easy to handle and has very little risk, and the injection work and the control of the injection amount are also easy, and the wastewater does not become excessively acidic,
Further, the treatment of wastewater is also very easy.

The present invention utilizes the fact that water into which carbon dioxide gas and / or carbonated water has been injected is excellent in removing alkali ions from the system to be cleaned, that is, has high rinsing ability. The purpose of use is not neutralization. Therefore, for example, in the case of continuously cleaning a pipe or the like, the injection of carbon dioxide gas in the present invention is monitored by monitoring the pH of the wastewater at the outlet of the pipe, and is stopped when the pH becomes about 9, and thereafter, the cleaning is performed only with water. May be.

When cleaning a device such as a dairy product food production device in which a plurality of devices for heating and mixing are connected by a pipe, the present invention is applied to a stationary cleaning method. After discharging the liquid food inside, a washing step of washing by passing an alkaline detergent as it is without disassembling the connection between the devices by these conduits, and then injecting carbon dioxide gas and / or carbonated water. If the washing and rinsing steps are performed in this order by passing water through, the time required for reconnecting the pipeline and assembling the device is eliminated, so that the time required for switching between production items and lots is reduced. It is possible to further reduce the time.

Next, a cleaning apparatus for carrying out the cleaning method of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a conventional stationary cleaning apparatus. A water tank, an acidic detergent tank, an alkaline detergent tank, a switching valve, and a liquid pump are provided.
Water, an acidic detergent, and an alkaline detergent are alternately supplied to three lines, respectively, and the pre-washing step, the washing step, and the rinsing step are performed in this order in each line. In addition, water, acidic detergent, alkaline detergent can be heated by the heat of steam in the heat exchanger,
The apparatus to be cleaned (connected to the “each line” in the figure; not shown) can be set to the optimum temperature required.

In the conventional apparatus shown in FIG. 1, an apparatus for injecting carbon dioxide and / or carbonated water into water used in the rinsing step as shown in FIG. 2 (in this example, carbon dioxide gas is injected into water used in the rinsing step) The cleaning method of the present invention can be realized.

The apparatus for injecting carbon dioxide into water used in the rinsing step shown in FIG. 2 includes pH meters 1 and 2, a carbon dioxide gas cylinder, a line mixer, a liquid pump, and a heat exchanger. p
The H meter 1 is provided at a drain outlet of a device to be cleaned, which is shown as a “manufacturing line” in the figure, and checks the pH of the waste water, and detects the end of the cleaning process when the pH becomes 8 to 9.5, for example. The injection of carbon dioxide gas is stopped by a control device (not shown).

On the other hand, the pH meter 2 monitors a change in pH of water into which carbon dioxide gas has been injected and which has been injected by stirring and mixing with a line mixer, and the abnormality has occurred (when the carbon dioxide gas cylinder becomes empty). Check if there is any.

This apparatus has a heat exchanger, and can heat the water into which the carbon dioxide gas has been injected as necessary to improve the cleaning efficiency. In the apparatus shown in FIG. 2, water which does not inject carbon dioxide gas into the production line can be supplied by switching the three-way switching valve in the figure as needed.

Further, another example of an apparatus for injecting carbon dioxide into water used in the rinsing step shown in FIG. 3 is shown. This apparatus has the same configuration as the apparatus shown in FIG. 2 except that a multi-way switching valve is provided to supply water into which carbon dioxide gas has been injected to many apparatuses to be cleaned (however, the cleaning in the apparatus shown in FIG. 2). The pH meter 1 provided at the drain outlet of the target device is omitted).

As described above, the apparatus for injecting carbon dioxide and / or carbonated water into the water used in the rinsing step as shown in FIG. 2 or FIG. 3 is combined with a conventional stationary cleaning apparatus to remove an alkaline detergent. The cleaning method according to the present invention can be easily implemented by using a cleaning device including a detergent supply unit that supplies the apparatus and a carbonated water supply unit that supplies water into which carbon dioxide gas and / or carbonated water has been injected. Can be.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The cleaning method of the present invention will be specifically described below using an example in which a test apparatus manufactured by assuming cleaning in a food manufacturing apparatus is used.

For the test, an apparatus schematically shown in FIG. 4 was used. Milk, alkaline detergent, or water into which carbon dioxide gas has been injected is supplied at a flow rate of 113 mL / min by a peristaltic pump manufactured by Coal Perm Co., Ltd., and a stainless steel tube (113 mL) having an inner diameter of 12 mm and a length of 1 m assuming a food production apparatus is used. , Hereinafter referred to as “piping”). In addition, liquefied carbon dioxide was used as carbon dioxide.

The pH of the treated water flowing out of the pipe assuming the food production apparatus is measured by a pH meter set in a 20 mL capacity water quality measuring vessel provided at the pipe outlet. In addition, a sample for measuring the electric conductivity and the sodium concentration was also collected from the treated water tank.
The carbon dioxide gas was injected until the pH at the outlet of the pipe reached 9.0, and thereafter, rinsing with water alone was continued.

All the water used was Tsukuba city tap water, pH 6.8, electric conductivity 300 μS / cm, and sodium ion concentration (measured by the atomic absorption method, the same applies hereinafter) of 31 mg / L. is there. In addition, the experiment was performed by setting the used milk, alkaline detergent, and Tsukuba City Water all at 25 ° C.

(Example 1) Commercial milk was allowed to flow through a pipe at a flow rate of 113 mL / min for 15 minutes, and then immediately switched to an alkaline detergent A. 113mL / m
The solution was flowed at a flow rate of in. This alkaline detergent A is
A solution obtained by mixing a surfactant Stavion manufactured by Ecolab and a 48% by weight aqueous sodium hydroxide solution at a volume ratio of 1:25, and further diluted 100 times (volume ratio) with distilled water. .

After the alkaline detergent A was kept flowing for 15 minutes, the water was switched to Tsukuba city water into which carbon dioxide was injected. That is, while flowing city water as raw water at a flow rate of 113 mL / min, carbon dioxide gas was continuously injected at a flow rate of 12.6 NmL / min and introduced into the pipe.

At this time, the time of switching from the alkaline detergent A to Tsukuba city water into which carbon dioxide gas was injected was set to 0 minute, and the subsequent changes in pH, electric conductivity, and sodium concentration of the treated water at the pipe outlet were measured. . The results are shown in Table 1 as Example 1. Table 1 also shows the results of Comparative Example 1 performed in the same manner as in Example 1 except that carbon dioxide was not injected into Tsukuba City Water.

[0031]

[Table 1]

From Table 1, when focusing on pH, Comparative Example 1
Then it is 30 to return to the level of Tsukuba city water which is raw water.
In contrast, the embodiment requires 9 minutes, which is 9 minutes or less, and it can be seen that the washing time can be significantly reduced even when focusing on the electric conductivity or the sodium ion concentration.

Of the indicators of the completion of washing, the sodium ion concentration is considered to be the most important as a guide for the completion of washing. However, when attention is paid to the sodium ion concentration, the time required for washing in the comparative example is 2/5, It can be seen that the cleaning step can be reduced to about 20%.

(Example 2) As in Example 1, except that
Alkaline detergent B instead of alkaline detergent A (100 times (volume ratio) Daikilate N-5N manufactured by Daisan Kogyo Co., Ltd.)
Was used for the study.

At this time, the time of switching from the alkaline detergent B to Tsukuba city water into which carbon dioxide gas was injected was set to 0 minute, and the subsequent changes in pH, electric conductivity and sodium concentration of the treated water at the pipe outlet were measured. . The results are shown in Table 2 as Example 2. Table 2 also shows the results of Comparative Example 2 performed in the same manner as in Example 2 except that carbon dioxide was not injected into Tsukuba City Water.

[0036]

[Table 2]

It can be seen from Table 2 that even when alkaline detergent B is used as the alkaline detergent, the washing time can be greatly reduced.

Example 3 A cleaning study was conducted in the same manner as in Example 2 except that a 0.01 N aqueous sodium hydroxide solution (alkaline detergent C) was used instead of the alkaline detergent B. The results are shown in Table 3 as Example 3.
In addition, Table 3 also shows the result of Comparative Example 3 performed in the same manner as in Example 3 except that carbon dioxide gas was not injected into Tsukuba City Water.

[0039]

[Table 3]

From Table 3, it was confirmed that even when only an aqueous solution of sodium hydroxide was used as the alkaline detergent, the washing time could be greatly reduced.

[0041]

According to the cleaning method of the present invention, the time required for cleaning and the amount of cleaning water used can be dramatically reduced, and the cost required for cleaning and the cost required for wastewater treatment are greatly reduced. This is an excellent cleaning method that can be reduced, and according to the present invention, it can cope with high-mix low-volume production without reducing productivity.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a conventional stationary cleaning apparatus.

FIG. 2 is a diagram showing an example of an apparatus for injecting carbon dioxide into water used in a rinsing step.

FIG. 3 is a diagram showing another example of an apparatus for injecting carbon dioxide into water used in a rinsing step.

FIG. 4 is a model diagram showing an apparatus used in the embodiment.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mika Imai 4-4 Midorigahara, Tsukuba, Ibaraki Pref. BC99 CC01 EC99

Claims (3)

[Claims] 1. A cleaning method comprising, in this order, a washing step of washing with an alkaline detergent, and a rinsing step of rinsing the detergent with water, wherein carbon dioxide and water are used in the water used in the rinsing step. A cleaning method characterized by injecting carbonated water. 2. A washing step of passing an alkaline detergent through a device to which a plurality of devices are connected by a pipe without disassembling the connection of the pipe, and a process of passing water through the apparatus. A stationary cleaning method for an apparatus having a washing step of rinsing and removing the detergent in this order, wherein carbon dioxide gas and / or carbonated water is injected into water used in the rinsing step. 3. A cleaning apparatus comprising: detergent supply means for supplying an alkaline detergent to a device to be cleaned; and carbonated water supply means for supplying water into which carbon dioxide gas and / or carbonated water has been injected.