JP7165331B2 - cleaning equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cleaning apparatus for cleaning machined parts and the like after machining.

In the automobile and electrical industries, "cleaning" plays an important role in the manufacturing process of parts. Here, "cleaning" of parts is performed to ensure the reliability of products and the quality of post-processes, and refers to the process of removing contaminants that have adhered during pre-processing.
Cleaning methods are broadly classified into wet and dry, and can be further classified into chemical cleaning and physical cleaning.
Chemical cleaning, typified by alkaline cleaning and solvent cleaning, removes dirt by dissolving and dispersing cleaning agents. Post-treatment such as draining and drying of the rinsing liquid is required, which increases the number of processes and the treatment time, which may lead to an increase in facility costs and energy.
On the other hand, physical cleaning, typified by blow cleaning, wipes away dirt with a gas flow such as air, and is positioned as a rational cleaning method because it has fewer steps and can be processed at high speed. However, it is difficult to achieve high cleaning quality compared to chemical cleaning, and because the cleaning energy is concentrated locally to remove dirt, a wide area or a part with a complicated shape is the area to be cleaned. Then, there are cases where it is difficult to apply.
Therefore, as a cleaning method combining the action of chemical cleaning and the action of physical cleaning, as shown in FIG. Such cleaning methods (commonly known as flow rate cleaning, direct pass cleaning, etc.) have been known (see, for example, Patent Documents 1 to 3).
In the conventional cleaning apparatus shown in FIG. 2, a box-shaped lower jig 100a with an open upper surface and an upside-down box-shaped upper jig 100b with an open lower surface are combined to accommodate the object W to be cleaned. a cleaning tank 101 capable of storing cleaning liquid; a cleaning liquid supply channel 104 comprising a pipe 102 and a circulation pump 103 for supplying the cleaning liquid in the cleaning tank 101 to the cleaning container 100; and a cleaning liquid discharge channel 105 consisting of a single pipe for discharging the cleaning liquid in the container 100 to the liquid storage tank 101 , and the circulation pump 103 is operated to forcibly circulate the cleaning liquid into the cleaning container 100 . The chemical and physical action of the cleaning liquid cleans and removes dirt attached to the object to be cleaned W, and the cleaned cleaning liquid is returned to the liquid storage tank 101 from the cleaning liquid discharge channel 105 and circulated.

JP-A-7-328565 JP-A-8-332463 JP-A-8-337890

In the conventional cleaning apparatus described above, cleaning is performed by allowing cleaning liquid to pass through the cleaning container 100 in one direction. Therefore, depending on the shape of the object to be cleaned, there is a risk that sufficient cleaning quality cannot be obtained.
SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning apparatus capable of improving cleaning quality.

In order to achieve the above object, the present invention
A cleaning apparatus in which an object to be cleaned is accommodated in a cleaning container and a cleaning liquid is supplied into the cleaning container to clean the object to be cleaned,
a cleaning liquid supply channel for supplying cleaning liquid into the cleaning container;
a cleaning liquid discharge channel for discharging the cleaning liquid in the cleaning container,
The cleaning liquid supply channel is routed from the first liquid storage tank capable of storing the cleaning liquid to the second liquid storage tank also capable of storing the cleaning liquid, and further from the second liquid storage tank via an on-off valve capable of switching between supply and stop of the cleaning liquid. provided to communicate with said washing vessel ,
Further, the second liquid storage tank is provided with a return passage for returning excess cleaning liquid exceeding a predetermined amount to the first liquid storage tank,
On the other hand, the cleaning liquid discharge channel is provided with suction means capable of sucking the outside air and the cleaning liquid in the cleaning container, and is connected from the cleaning container to the first liquid storage tank via the suction means. and
closing the on-off valve to stop the supply of the cleaning liquid into the cleaning container, and sucking the outside air in the cleaning container with the suction means to create a negative pressure;
while the inside of the cleaning container is under a negative pressure, the on-off valve is opened to supply the cleaning liquid into the cleaning container;
Further, in a state in which the cleaning liquid is supplied to the cleaning container, the on-off valve is closed to stop the supply of the cleaning liquid, and the cleaning liquid in the cleaning container is sucked by the suction means and discharged to the cleaning liquid discharge channel. To provide a cleaning device that

Further, as described in claim 2 , the suction means has a circulation flow path for circulating the cleaning liquid in the first liquid storage tank with a circulation pump, an inflow section, an outflow section, and a suction section, and the inflow section. and an ejector in which the outflow part is connected to the middle of the circulation flow path, and the cleaning liquid discharge flow path is connected to the suction part of the ejector. .

Further, as described in claim 3 , the second liquid storage tank is provided at a higher position than the cleaning container, and when the on-off valve is open, the cleaning liquid in the second liquid storage tank is discharged under its own weight. 3. The washing apparatus according to claim 1, wherein the liquid can flow into the washing container by the dropping of the liquid and the suction action of the suction means.

According to the cleaning apparatus of the present invention, the cleaning liquid supplied by the cleaning container is under a negative pressure and the suction action of the suction means increases the flow rate of the cleaning liquid, so that the cleaning liquid flows into the cleaning container in a turbulent state and is stored therein. Since it circulates all over the surface of the object to be cleaned, it is possible to efficiently remove adhering dirt. In addition, since the cleaning liquid in the cleaning container is quickly discharged by the suction action of the suction means, it is possible to drain the liquid from the object to be cleaned in a short time. Therefore, it is possible to improve the cleaning quality and reduce the cleaning cost.

In addition, according to the cleaning apparatus of the present invention , the excess cleaning liquid exceeding the predetermined amount stored in the second liquid storage tank is returned to the first liquid storage tank through the return flow path. 2 The object to be washed can be washed by simply opening and closing the on-off valve while keeping the amount of liquid supplied to the liquid storage tank constant. Therefore, since it is not necessary to control the liquid feeding amount of the cleaning liquid supply channel for each cleaning timing, it is possible to simplify the structure and reduce the operating cost and cleaning cost.

According to the cleaning apparatus of claim 2 , the ejector connected in the middle of the circulation channel can suck the outside air and the cleaning solution from the inside of the cleaning container, and the sucked cleaning solution flows from the ejector to the circulation channel. , and automatically returns to the first liquid storage tank, the structure is simple, the cost is low, and maintenance is easy.

Further, according to the cleaning apparatus of claim 3 , the drop from the liquid surface of the second liquid storage tank to the cleaning container, the negative pressure in the cleaning container due to the suction action of the suction means, and the continuous suction force As a result, the flow velocity of the cleaning liquid supplied into the cleaning container is rapidly increased, so that the flow of the cleaning liquid can be reliably changed from laminar flow to turbulent flow in the cleaning container.

It is a schematic flow diagram showing the entire cleaning apparatus. It is a schematic flow diagram showing the entire conventional cleaning apparatus.

An embodiment of the present invention will be described below with reference to FIG.
A cleaning apparatus 1 of the present invention is for cleaning an object W to be cleaned in a cleaning container 2 and supplying a cleaning liquid 3 into the cleaning container 2 to clean the object W to be cleaned.

[1. Cleaning liquid and object to be cleaned]
The object to be cleaned W to be cleaned by the cleaning device 1 of the embodiment is a machined metal part that is stained with oils and fats, and the cleaning liquid 3 to be used is an alkaline cleaning agent.
The objects W to be washed are sequentially sent one by one to a washing point P provided in the middle of the continuous conveyer 4, or a group of a plurality of objects that can be accommodated in the washing container 2, or they are not shown in the drawing. , and are sequentially sent in the above-mentioned units to a washing point provided between two conveyors arranged in the conveying direction by an appropriate transfer device. The object to be washed W to be stopped is washed in the above unit.

[2. Cleaning container]
The cleaning container 2 comprises a box-shaped lower jig 2a with an open upper surface and an upside-down box-shaped upper jig 2b with an open lower surface. It can be sealed by bringing them into contact with each other or connecting them through a part of the frame 4a of the conveyer 4. As shown by the imaginary line in FIG. It can be opened and closed.

The cleaning device 1 of the embodiment has a cleaning container 2 as a core, a cleaning liquid supply channel 5 for supplying the cleaning liquid 3 into the cleaning container 2, and a cleaning liquid discharge channel 6 for discharging the cleaning liquid 3 supplied to the cleaning container 2. and has.

[3. Cleaning liquid supply channel]
The cleaning liquid supply channel 5 communicates with a first liquid storage tank 7 capable of storing the cleaning liquid 3, a second liquid storage tank 8 also capable of storing the cleaning liquid 3, and the first liquid storage tank 7 and the second liquid storage tank 8. a cleaning liquid supply pump 10 provided in the middle of the first supply pipeline 9; a second supply pipeline 11 that communicates the second liquid storage tank 8 and the cleaning container 2; 2 and an on-off valve 12 provided in the middle of the pipe 11 .

The first liquid storage tank 7 is arranged lower than the cleaning container 2, while the second liquid storage tank 8 is arranged higher than the cleaning container 2 (preferably directly above the cleaning container 2). The cleaning liquid 3 in the first liquid storage tank 7 is lifted to the second liquid storage tank 8 at a high place by the cleaning liquid supply pump 10 in the first supply pipe 9 .

The second liquid storage tank 8 communicates with the outside air through a vent pipe 13 , and the atmospheric pressure cross-sectional area of the cleaning liquid 3 stored in the second liquid storage tank 8 communicates with the second liquid storage tank 8 . It is sufficiently wide compared to the cross-sectional area of the second supply pipe 11 that is connected.
Further, the second liquid storage tank 8 is equipped with a heat exchanger 14 capable of adjusting the temperature of the cleaning liquid 3 to a set temperature.
Furthermore, in the second liquid storage tank 8, an overflow tank 16 having a return flow path 15 communicating with the first liquid storage tank 7 is arranged in parallel via a weir 17. Excess cleaning liquid 3 exceeding the amount (preferably, the amount of cleaning liquid 3 required for one cleaning) overflows the weir 17 and falls into the overflow tank 16. 1 to return to the liquid storage tank 7 . Therefore, the cleaning liquid supply pump 10 of the first supply pipe 9 can be efficiently operated at a constant output (flow rate) regardless of the cleaning timing.

The on-off valve 12 is, for example, an electromagnetic valve driven by a solenoid or the like.

[4. Cleaning liquid discharge channel]
The washing liquid discharge channel 6 is formed by a discharge pipe 18 connected to the lower jig 2a of the washing container 2 and a suction means 19 capable of sucking the outside air and the washing solution 3 in the washing container 2 through the discharge pipe 18. Become.
The suction means 19 includes a circulation flow path 20 that exits from the first liquid storage tank 7 and makes a U-turn to the first liquid storage tank 7, and a circulation pump that circulates the cleaning liquid 3 in the first liquid storage tank 7 through the circulation flow path 20. 21 and an ejector (three-way valve) 22 connected in the middle of the circulation flow path 20 .
This ejector 22 is a known one having an inflow portion 22a, an outflow portion 22b, and a suction portion 22c. A discharge pipe 18 of the discharge channel 6 is connected.

[5. Washing method]
Next, a cleaning method by the cleaning device 1 of the embodiment will be described.
In the cleaning apparatus 1, the cleaning liquid supply pump 10 of the cleaning liquid supply channel 5 and the circulation pump 21 of the cleaning liquid discharge channel 6 are always operated at substantially constant output, and the on-off valve 12 of the cleaning liquid supply channel 5 is closed. The middle of the second supply pipe 11, that is, the bottom of the second liquid storage tank 8 is closed.
Therefore, in the cleaning liquid supply channel 5, the cleaning liquid 3 is pumped from the first liquid storage tank 7 to the second liquid storage tank 8 at a substantially constant flow rate, and the excess liquid exceeding the predetermined storage amount in the second liquid storage tank 8 is discharged. The cleaning liquid 3 flows over the weir 17 into the overflow tank 16, and the cleaning liquid 3 flows from the overflow tank 16 through the return channel 15 and returns to the first liquid storage tank 7 by its own weight.
On the other hand, in the cleaning liquid discharge channel 6, the cleaning liquid 3 stored in the first liquid storage tank 7 always circulates through the circulation channel 20 at a substantially constant flow rate. Outside air of the cleaning container 2 (lower jig 2a) is always sucked from 22c. Note that the mechanism by which the outside air is sucked from the suction portion 22c of the ejector 22 by the flow of liquid is well known, so the explanation thereof will be omitted.

The cleaning container 2 of the cleaning apparatus 1 is held by the upper jig as shown by the imaginary line in FIG. 2b rises and waits for acceptance. Then, when the object W to be cleaned stops at the cleaning point P, the upper jig 2b descends as indicated by the solid line in the figure to accommodate the object W to be cleaned in a sealed state between itself and the lower jig 2a.

As described above, the ejector 22 always sucks the outside air into the cleaning container 2, so that when the cleaning container 2 is sealed, the inside of the cleaning container 2 is decompressed from the atmospheric pressure to be in a negative pressure state.
In this state, when the on-off valve 12 is opened to open the bottom of the second liquid storage tank 8, the cleaning liquid 3 in the second liquid storage tank 8 is discharged from the height from the liquid surface to the upper jig 2b and the gravitational acceleration. It will be supplied into the cleaning container ₂ at a flow rate of V0 (Torricelli's theorem). Further, in the washing container 2, the flow velocity of the supplied washing liquid 3 is accelerated by the negative pressure state and the continuous suction action of the ejector 22. As shown in FIG. At this time, the cleaning liquid 3 becomes a liquid flow equal to or greater than the critical Reynolds number (Re=2300) in the cleaning container 2, and the laminar flow up to that point changes to a turbulent flow. By changing the flow of the cleaning liquid 3 flowing in the cleaning container 2 from laminar flow to turbulent flow in this manner, the thickness of the boundary layer at the interface between the surface of the object W to be cleaned and the cleaning liquid 3 is reduced, so that the thickness of the boundary layer is reduced to the order of several microns to submicrons. removability of the particles is remarkably improved. In addition, since the turbulent flow is formed, the design of the flow path in the cleaning vessel 2 is simplified, and a plurality of objects W to be cleaned having different shapes can be mixed, so that the versatility of the cleaning apparatus 1 is enhanced. increase.
The cleaning liquid 3 circulating through the object to be cleaned W is returned to the first liquid storage tank 7 via the ejector 22 together with the removed dirt, joining the cleaning liquid 3 circulating in the circulation flow path 20 .

After finishing the cleaning, the cleaning device 1 switches the open/close valve 12 that was previously opened to close the bottom of the second liquid storage tank 8 , thereby stopping the supply of the cleaning liquid 3 into the cleaning container 2 . While the on-off valve 12 is open, the cleaning liquid 3 in the second liquid storage tank 8 continues to flow out and the level of the cleaning liquid drops. is continuously supplied, the second liquid storage tank 8 recovers the predetermined storage amount as soon as the on-off valve 12 is closed.
On the other hand, even after the on-off valve 12 is closed and the supply of the cleaning liquid 3 is stopped, the suction action by the ejector 22 continues without stopping, so the cleaning liquid 3 remaining in the cleaning container 2 is forcibly sucked out to the end. Therefore, the cleaning object W can be drained well.
Since the cleaning container 2 is sealed, the inside of the container is decompressed and the negative pressure develops. When this is opened, the air is introduced into the cleaning container 2 at once, and the cleaning liquid remaining on the object W to be cleaned can be wiped off, and furthermore, the object W to be cleaned can be drained well.
By intermittently repeating opening and closing of the on-off valve 12, a water hammer effect (air hammer phenomenon) can be accompanied, so that cleaning performance and draining performance of the cleaning liquid can be further improved.

When the cleaning in the cleaning container 2 is completed as described above and all the cleaning liquid 3 in the cleaning container 2 is discharged, the upper jig 2b is raised to the standby position, and the transport conveyor 4 is operated to perform the cleaning point P. One or a set of objects W to be washed together are sent to the next step, and the next object W to be washed is moved to the washing point P.
Thereafter, the cleaning process described above by the cleaning device 1 is repeatedly performed.

By the way, when the above cleaning process is repeated, oil stains that cannot be completely dispersed in the cleaning liquid 3 eventually rise to the surface in the first liquid storage tank 7, for example, at the level shown by the dashed line in FIG. For separation, the first liquid storage tank 7 is provided with a waste oil drain 23 for draining such floated oil stains.
Further, in order to ensure the discharge of oil stains by the waste oil drain 23, it is desirable that the cleaning liquid to be used is water-soluble with good oil/water separation properties. In particular, a cleaning liquid in which the dissolution characteristics of fats and oils changes with temperature is suitable.
Some cleaning liquids 3, such as nonionic surfactants and glycol ether solvents, are in a transparent or translucent aqueous solution state at low temperatures, but when the liquid temperature is raised, it becomes cloudy from a certain temperature, and further increases the temperature. Some phase separates from water as it is raised. The temperature at which this phase separation occurs is called the cloud point of the cleaning liquid. In addition, this phenomenon returns to the state of the original transparent aqueous solution when the liquid temperature is lowered below the cloud point. Therefore, when the temperature of the cleaning liquid is raised to a temperature higher than the cloud point, the phase-separated cleaning agent component becomes highly lipophilic (low water concentration), and the cleaning (dissolving) ability for oils and fats is improved. In addition, when the temperature of the cleaning liquid is lowered to below the cloud point, it becomes a transparent or translucent aqueous solution, that is, in a state of high hydrophilicity (low solubility of oils and fats), and the oils and fats dissolved in the cleaning agent components are separated from the cleaning liquid. It floats and separates due to the difference in specific gravity from the cleaning liquid.
Cleaning liquids with such characteristics include, for example, the MA series (MA-60, etc.) manufactured by Musashi Techno Chemical Co., Ltd., the Clean Through "LC-800" series manufactured by Kao Corporation, Pine Alpha ST-251EVA manufactured by Arakawa Chemical Co., Ltd., and Sanwa There is Sunclean XL-35 manufactured by Yuka Co., Ltd., and these are suitable for discharging oil stains from the waste oil drain 23 .
As operating conditions for using these cleaning liquids 3, the temperature of the cleaning liquid in the second liquid storage tank 8 is heated to a temperature higher than the cloud point of the cleaning liquid 3 by the heat exchanger 14, and the cleaning liquid 3 is further stirred by a stirring means (not shown). Stir to form an emulsion. Further, the cleaning liquid temperature of the cleaning liquid 3 is kept below the cloud point by providing cooling means (not shown) in the first liquid storage tank 7 .
In this way, when combined with a cleaning agent that changes the dissolution characteristics of oils and fats depending on the liquid temperature, it is possible to circulate and reuse the cleaning liquid with a simple mechanism.・Energy-saving, environment-friendly and highly versatile environment-friendly cleaning system can be realized.

Although the embodiments of the present invention have been described above, the present invention is of course not limited to the above embodiments. For example, in the embodiment, the objects W to be washed W are washed one by one or a group of plural objects that can be accommodated in the washing container 2 are washed continuously. You may make it process separately. In the case of continuous treatment and small lot production as in the embodiment, however, the cleaning process can be carried out in-line because the equipment size is small, which is more preferable in that reliability and rationality can be improved.
Also, in the embodiment, the ejector 22 is used as the suction means 19, but instead of such an ejector 22, a separate vacuum pump may be provided.
Further, the on-off valve 12 is not limited to an electric valve such as an electromagnetic valve, and may be a manual valve that is manually switched.

REFERENCE SIGNS LIST 1 ... cleaning device 2 ... cleaning container 3 ... cleaning liquid 5 ... cleaning liquid supply channel 6 ... cleaning liquid discharge channel 7 ... first liquid storage tank 8 ... second liquid storage tank 12 ... open/close valve 15 ... return channel 19 ... suction means DESCRIPTION OF SYMBOLS 20...Circulation flow path 21...Circulation pump 22...Ejector 22a...Inflow part 22b...Outflow part 22c...Suction part W...Item to be washed

Claims (3)

A cleaning apparatus in which an object to be cleaned is accommodated in a cleaning container and a cleaning liquid is supplied into the cleaning container to clean the object to be cleaned,
a cleaning liquid supply channel for supplying cleaning liquid into the cleaning container;
a cleaning liquid discharge channel for discharging the cleaning liquid in the cleaning container,
The cleaning liquid supply channel is routed from the first liquid storage tank capable of storing the cleaning liquid to the second liquid storage tank also capable of storing the cleaning liquid, and further from the second liquid storage tank via an on-off valve capable of switching between supply and stop of the cleaning liquid. provided to communicate with said washing vessel ,
Further, the second liquid storage tank is provided with a return passage for returning excess cleaning liquid exceeding a predetermined amount to the first liquid storage tank,
On the other hand, the cleaning liquid discharge channel is provided with suction means capable of sucking the outside air and the cleaning liquid in the cleaning container, and is connected from the cleaning container to the first liquid storage tank via the suction means. and
closing the on-off valve to stop the supply of the cleaning liquid into the cleaning container, and sucking the outside air in the cleaning container with the suction means to create a negative pressure;
while the inside of the cleaning container is under a negative pressure, the on-off valve is opened to supply the cleaning liquid into the cleaning container;
Further, in a state in which the cleaning liquid is supplied to the cleaning container, the on-off valve is closed to stop the supply of the cleaning liquid, and the cleaning liquid in the cleaning container is sucked by the suction means and discharged to the cleaning liquid discharge channel. A cleaning device characterized by: The suction means has a circulation flow path for circulating the cleaning liquid in the first liquid storage tank by a circulation pump, an inflow section, an outflow section, and a suction section, and the inflow section and the outflow section are arranged in the middle of the circulation flow path. 2. The washing apparatus according to claim 1 , further comprising an ejector connected to the suction portion of the ejector, and the washing liquid discharge flow path being connected to the suction portion of the ejector. The second liquid storage tank is provided at a higher position than the cleaning container, and when the on-off valve is open, the cleaning liquid in the second liquid storage tank drops due to its own weight and is sucked by the suction means. 3. The washing apparatus according to claim 1, wherein the water can flow into the washing container by means of a .

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