JP4176295B2 - How to clean the tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for cleaning the inner surface of a tank with a cleaning liquid. More specifically, the present invention relates to a tank that can clean the inner surface of a mobile tank used in a small variety of various types of production equipment with a different cleaning liquid for each type of preparation. The present invention relates to a cleaning method.
[0002]
[Prior art]
In recent years, moving tank type preparation equipment has been used as production equipment for small quantities of various types of paints and chemicals. Such a moving tank type preparation equipment is provided with, for example, an injection station, a plurality of reaction stations, a distillation station, a sampling / outtake station, a discharge station, a washing station, and the like by moving a moving tank between them. From the charging of the reaction product to the discharge of the reaction product.
[0003]
In such a mobile tank type preparation facility, multiple types of liquid materials are often prepared in the same tank for multi-product production. In this case, the inner surface of the tank is well cleaned with different cleaning liquids for each prepared product type. It is required to do. The liquid substance is obtained by product preparation and includes a solution, a mixed liquid, a dispersion, and the like.
[0004]
As a method for cleaning the inner surface of the tank, a spray method in which cleaning liquid is jetted and cleaned from a spray ball fed into the tank, as proposed in Japanese Patent No. 2582273, is proposed in Japanese Patent Laid-Open No. 6-126263. There was a brushing method to wash with a rotating brush.
[0005]
For example, there is a spray type cleaning apparatus as shown in FIG. In FIG. 5, reference numeral 31 denotes a moving tank, which is provided with a sheath pipe 32 at the upper part and a waste liquid pipe 33 at the lower part. A cleaning liquid supply device 34 is connected to an elevating spray cleaning device 36 through a cleaning pipe 35. The elevating spray cleaning device 36 is provided with an extendable cover case 37, a cleaning liquid supply pipe 38 and a spray ball 39. In addition, a waste liquid device 40 is provided, and a drive cylinder 41 is provided. The drive cylinder 41 can be connected to a waste liquid pipe for connection 42 that can be expanded and contracted.
[0006]
In such a cleaning device, the cover case 37 is connected to the sheath tube 32, the cleaning liquid supply pipe 38 is inserted into the moving tank 31, and the cleaning liquid is sprayed from the spray ball 39 to clean the inner surface of the moving tank 31. Is going.
[0007]
[Problems to be solved by the invention]
However, as described above, the mobile tank is used as a small-lot, high-variety production facility, and since this type is frequently switched, cleaning liquid residue and cleaning that were rarely found in fixed tanks used as dedicated-variety production facilities. Troubles during product preparation due to defects occurred frequently.
[0008]
That is, in the brushing method, the residue adhered to the brush portion contaminates the tank during cleaning, and may cause poor preparation as a contamination during product preparation after cleaning. In the spray method, the cleaning liquid remaining in the tank is agglomerated with the prepared liquid, and the cleaning liquid remaining in the cleaning pipe is agglomerated with the dispersion in the preparation liquid remaining in the tank at the next cleaning. This may cause poor product preparation.
[0009]
In order to eliminate contamination caused by such cleaning, a cleaning device and a moving tank can be dedicated, but this is not preferable because the cost and scale of the equipment are large.
[0010]
The present invention solves the above problems, and when the inner surface of the moving tank is cleaned with a different cleaning liquid for each of the prepared varieties, the cleaning liquid does not remain in the tank and the cleaning pipe, so that the product preparation can be performed satisfactorily. An object is to provide a cleaning method.
[0011]
[Means for Solving the Problems]
The tank cleaning method according to the present invention is a method in which a cleaning liquid is sprayed onto the inner surface of a tank via a cleaning pipe, and the cleaning liquid remaining in the tank is replaced with a solvent or a main solvent of a product to be prepared next. It has a replacement step and a solvent removal step of removing the solvent or main solvent remaining in the cleaning pipe in the cleaning liquid replacement step with an inert gas .
[0012]
In the tank cleaning method according to the present invention, the cleaning liquid remaining in the tank is replaced with the solvent or main solvent of the product to be prepared next to prevent contamination when the next product is prepared. The remaining solvent or main solvent is removed with nitrogen to prevent the occurrence of poor cleaning during the cleaning after the next preparation.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The cleaning liquid is preferably the same solvent or main solvent used for preparing the product remaining in the tank. Moreover, when using a flammable solvent, an odor, or a thing with a possibility of harming health as a washing | cleaning liquid, it is preferable to connect an exhaust port to an exhaust duct. A pressure adjusting valve may be provided at the exhaust port. In this case, cleaning can be performed while keeping the pressure in the tank constant. Furthermore, when a flammable solvent is used as the cleaning liquid, the air can be replaced with an inert gas (often using nitrogen), and the oxygen concentration in the tank can be controlled with a gas concentration meter or oxygen concentration meter. preferable.
[0014]
When a solvent is used as the cleaning liquid, water, methanol, ethanol, propanol, benzene, toluene, acetone, methyl ethyl ketone, or the like can be used as the solvent. The same applies to the solvent used for the replacement of the cleaning liquid.
[0015]
The tank to which the tank cleaning method according to the present invention is applied is not particularly limited, but is particularly suitable when the tank is a mobile tank used as a low-volume, multi-product production facility. In order to facilitate cleaning, surface treatment such as fluororesin coating or glass coating can be applied to the inner surface of the tank.
[0016]
In the tank cleaning method of the present invention, the solution to be cleaned is not particularly limited and can be applied to a solution for preparing various products, but can be particularly preferably applied to a liquid containing a pigment dispersion.
[0017]
A tank cleaning method according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a state before cleaning of a mobile tank cleaning device for carrying out a tank cleaning method, FIG. 2 is a schematic diagram showing a state during cleaning of the mobile tank cleaning device, and FIG. 3 is a mobile tank cleaning device. FIG. 4 is a schematic view showing a state of the above moving tank cleaning apparatus during nitrogen replacement.
[0018]
In these drawings, reference numeral 1 denotes a moving tank. Above the moving tank 1, a spray tube insertion sheath tube 2 and an exhaust pipe 3 for exhausting the moving tank 1 are provided. 3, automatic opening / closing valves 4 and 5 are respectively provided. In addition, a waste liquid pipe 6 for discharging cleaning waste liquid and main solvent is provided at the lower part of the moving tank 1, and an automatic opening / closing valve 7 is also provided in the waste liquid pipe 6 so as to keep the inside of the moving tank 1 sealed. Yes.
[0019]
On the other hand, in the cleaning station, an elevating spray cleaning device 8 is provided above the movable tank 1, and the elevating spray cleaning device 8 is an extendable cover case connected to the sheath tube 2. 9, and a retractable cleaning liquid supply pipe 10 that can be moved back and forth in the cover case 9. A spray ball 11 is provided at the tip of the cleaning liquid supply pipe 10. The elevating spray cleaning device 8 is connected to a cleaning pipe 12, and this cleaning pipe 12 is connected to a nitrogen gas supply device 14 and a cleaning liquid supply device 15 via an automatic switching valve 13. The cleaning liquid supply device 15 is connected to a supply source (not shown) of various cleaning liquids and solvents, and can supply a desired cleaning liquid or solvent by appropriately switching the flow paths.
[0020]
Further, an exhaust device 16 is provided above the moving tank 1, and this exhaust device 16 is connected to a drive cylinder 17 for connecting a pipe, and this drive cylinder 17 is connected to the exhaust pipe 3. A telescopic connection pipe 18 is provided, and an automatic opening / closing valve 19 is provided near the tip.
[0021]
A waste liquid device 20 is provided below the moving tank 1, and the waste liquid device 20 is connected to a drive cylinder 21 for pipe connection. The drive cylinder 21 is telescopically connected to the waste liquid pipe 6. A connecting pipe 22 is provided, and an automatic opening / closing valve 23 is provided in the vicinity of the tip thereof. In addition, the waste liquid device 20 is provided with a discharge pipe group 24 that forms a plurality of flow paths so that it can be discharged individually according to the type of cleaning liquid and solvent to be used.
[0022]
Note that 25 is a paddle, 26 is a motor for rotating the paddle, and 27 is a wheel for moving each station.
[0023]
A method of cleaning the mobile tank in the mobile tank cleaning apparatus as described above will be described.
[0024]
First, as shown in FIG. 2, the elevating spray cleaning device 8 and the drive cylinders 17 and 21 are driven, and the cover case 9 and the sheath tube 2, the connection pipe 18 and the exhaust pipe 3, the connection pipe 22 and the waste liquid pipe 6. Are connected to make the inside of the moving tank 1 hermetically sealed, and the automatic opening / closing valves 4, 5, 7, 19, 23 are opened.
[0025]
Next, the spray ball 11 is inserted to the lowest point in the moving tank 1, and the cleaning liquid supply device 15 is switched to the flow path of the cleaning liquid, and the cleaning liquid selected from the spray ball 11 is sprayed to clean the inner surface of the moving tank 1. To do.
[0026]
The spray pressure of the cleaning liquid can be set in the range of 9.8 × 10 ^{4 to} 980 × 10 ⁴ Pa (1 to 100 kgf / cm ² ), and preferably 9.8 × 10 ^{4 to} 196 × 10 ⁴ Pa (1 to 20 kgf). / Cm ² ), more preferably in the range of 19.6 × 10 ^{4 to} 98 × 10 ⁴ Pa ( ^{2 to} 10 kgf / cm ² ). The rotation speed of the spray ball is preferably about 1 to 100 rpm.
[0027]
Cleaning with a spray ball can also be performed by moving the spray ball up and down, that is, raising and lowering between the lowest point and the uppermost point (the uppermost point in the tank, specifically near the lower part of the upper lid). At this time, the number of times the spray ball is raised and lowered varies depending on the cleaning performance of the object to be cleaned, but is set to about 1 to 30 times. Moreover, the raising / lowering speed of a spray ball can use the range of 0.1-10 m / min, Preferably it is 0.2-8 m / min, More preferably, it is the range of 0.5-5 m / min.
[0028]
When the cleaning is completed, as shown in FIG. 3, the spray ball 11 is raised to the highest point, and the cleaning liquid supply device 15 is switched to the main solvent flow path used for the next preparation variety and selected from the spray ball 11. The main solvent is sprayed, and the cleaning liquid remaining in the moving tank 1 is discharged. The time T1 for spraying the main solvent is appropriately set depending on the internal volume and shape of the tank, but is usually set to about 5 to 30 seconds. By the main solvent spray, the cleaning liquid is removed from the transfer tank 1 and only the main solvent remains.
[0029]
Next, the automatic switching valve 13 is switched to the nitrogen gas supply device 14 side, and as shown in FIG. 4, the spray ball 11 is lowered again to the lowest point, and nitrogen gas is sprayed from the spray ball 11. Then, the main solvent remaining in the cleaning pipe 12 and the cleaning liquid supply pipe 10 is extruded with nitrogen gas and further discharged out of the moving tank 1. The nitrogen gas spraying time T2 is appropriately set depending on the internal volume of the tank, the nitrogen spraying flow rate, and the like, but is usually preferably about 5 to 30 seconds, but is not limited thereto. Thereby, it is possible to prevent a cleaning failure from occurring during the next cleaning.
Thereby, the tank inner surface can be satisfactorily cleaned with different cleaning liquids for each of the prepared varieties.
[0030]
【The invention's effect】
In the present invention, after the spray cleaning, the cleaning liquid remaining in the moving tank is first replaced with the main solvent of the next prepared varieties, so that it is possible to prevent a preparation failure during the next preparation, and further, the cleaning liquid remains in the cleaning pipe. Since the main solvent is removed with nitrogen gas, it is possible to prevent the occurrence of poor cleaning during the next cleaning. Therefore, the inner surface of the tank can be satisfactorily cleaned with different cleaning liquids for each of the prepared varieties, the purity of the prepared solution is improved, and the production of the product can be stabilized.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a state before cleaning of a mobile tank cleaning apparatus for performing a tank cleaning method according to the present invention.
FIG. 2 is a schematic view showing a state of the mobile tank cleaning device that performs the tank cleaning method according to the present invention during cleaning.
FIG. 3 is a schematic view showing a state when a main solvent is replaced in a moving tank cleaning apparatus for carrying out a tank cleaning method according to the present invention.
FIG. 4 is a schematic view showing a state of the moving tank cleaning apparatus for carrying out the tank cleaning method according to the present invention at the time of nitrogen replacement.
FIG. 5 is a schematic diagram of a conventional mobile tank cleaning apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Moving tank 2 ... Sheath pipe 10 ... Cleaning liquid supply pipe 11 ... Spray ball 12 ... Cleaning pipe 13 ... Automatic switching valve 14 ... Nitrogen gas supply apparatus 15 ... Cleaning liquid supply apparatus 16 ... Exhaust apparatus 20 ... Waste liquid apparatus

Claims (3)

In the method of spraying the cleaning liquid onto the inner surface of the tank via the cleaning pipe, the cleaning liquid replacement step of replacing the cleaning liquid remaining in the tank with the solvent or main solvent of the product to be prepared next, and the cleaning liquid replacement step And a solvent removal step of removing the solvent or main solvent remaining in the washing pipe with an inert gas .   The tank cleaning method according to claim 1, wherein the tank is a moving tank.   The tank cleaning method according to claim 1, wherein the liquid to be cleaned is a liquid containing a pigment dispersion.

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