JPH10296583A - Defoaming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively eliminate foaming of a coolant in a circulating route of the coolant. SOLUTION: A used coolant reserved in a primary reservoir tank 6 is defoamed as it is pressurized gently in a displacement type pump 7. Additionally, it is force fed with pulsation from a discharge port of the displacement type pump 7, but the pulsation is negated in a rectifier tube 8. Thereafter, it is reserved in a secondary reservoir tank 10 without foaming by smoothly decompressing it in an air releasing pipe 9 and decelerating it. Consequently, it comes to be possible to constantly supply a coolant without foaming to a grinder 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defoaming apparatus for eliminating foaming of a coolant in a coolant circulation path.

[0002]

2. Description of the Related Art When machining in a grinding machine or the like, coolant is supplied to a grinding tool and a surface to be ground to cool the grinding tool and the object to be ground and to remove chips generated from the surface to be ground. ing. By the way, the coolant that has completed the above-described role is recovered and filtered to remove impurities such as chips, and then supplied to the surface to be ground again. In the coolant circulation path, bubbling occurs in the coolant due to the following various factors.

[0003] For example, when used coolant passes through a pump that pumps the storage tank, the coolant foams. When a centrifugal filtration device is used as a filtration device for impurities, the coolant is agitated and a large amount of air is mixed in the liquid, which causes foaming. Furthermore, when a so-called centerless grinder is used for the grinding device, the width of the grindstone is wider than that of the cylindrical grinder, so that the contact area between the coolant and the air increases, and foaming easily occurs. Also, in order to improve the finished surface roughness,
For example, when a coolant having more excellent detergency is used, the coolant tends to foam.

[0004] If the coolant containing air bubbles is supplied to the surface to be ground, the processing quality is degraded. Therefore, it is necessary to take some form of defoaming in the coolant circulation path. . FIG. 3 shows an example of a conventional defoaming means. Storage tank 1
Is to temporarily store coolant in order to reuse used coolant. And, at the outlet of the drain pipe 2 for sending the coolant to the storage tank 1,
A conical current plate 3 is provided. The coolant that has flowed out of the drain pipe 2 is guided in a thin layer along the wall surface of the current plate 3 as indicated by an arrow A. During this time, bubbles of the coolant are defoamed and stored in the storage tank. In some cases, defoaming is performed by using a filter element or the like instead of the current plate 3. Furthermore, when sufficient defoaming cannot be performed even by using such defoaming means, the state of generation of foam is monitored, and measures such as manually adding an antifoaming agent to the storage tank 1 are taken. I have.

[0005]

However, the conventional defoaming means has the following problems. For example, when performing defoaming by a filter element, if the coolant after filtration contains a small amount of chips, the filter element is clogged after a certain period of use. However, it was actually difficult to completely remove the chips, and replacement of the filter element became indispensable. In addition, when an antifoaming agent is added to the coolant, the cleaning ability and the cooling ability of the coolant are reduced, and the coolant needs to be replaced frequently. In either case, the man-hour required for replacement increases and industrial waste increases.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to clean and cool a surface to be ground by effectively eliminating bubbling of a coolant in a coolant circulation path. And to obtain a high-quality product stably, reduce the number of work steps related to the grinding device, and reduce industrial waste.

[0007]

According to the present invention, there is provided an anti-foaming apparatus for solving the above-mentioned problems. In the de-foaming apparatus, a coolant circulation path is connected to a coolant pressurizing means and a tank for storing the coolant. In addition, an elastically deformable conduit is arranged. Then, the pulsation of the coolant causing foaming in the coolant flowing in the circulation path is caused by the expansion and contraction of the elastically deformable conduit,
Absorbs by expansion and compression and prevents foaming of the coolant.

Further, in the present invention, it is preferable to use a positive displacement pump for the pumping means. The positive displacement pump does not agitate the coolant flowing through the pump, and operates even when the coolant sucked from the suction port of the pump contains air bubbles. A discharge pressure is generated in the fluid.), So that the coolant can be discharged without lowering the suction efficiency. Moreover, due to the increase in the pressure of the coolant in the pump, the air bubbles disappear,
In addition, the pulsation of the coolant at the discharge port is canceled by the elastically deformable conduit, and the coolant in a defoamed state can be sent to the tank.

Further, in the present invention, it is desirable to provide an atmosphere open pipe at the outlet of the elastically deformable pipe. According to this configuration, the high-pressure coolant, which has been defoamed by pressurization in the positive displacement pump and whose pulsation at the discharge port of the pump has been eliminated by the elastically deformable conduit, is gently depressurized by the open-to-atmosphere pipe. By doing
It can be sent to the tank while maintaining the defoamed state.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 schematically shows a defoaming apparatus according to an embodiment of the present invention. This defoaming device includes a grinding machine 4
Is formed in a coolant circulation path 5 for supplying coolant to the coolant. As shown in the figure, the circulation path 5 has a primary storage tank 6, a positive displacement pump 7, which is a means for pumping coolant, a rectifying pipe 8, an atmosphere opening pipe 9, a secondary storage tank 10, a supply pump 11 and a supply pipe 12. In addition, an unillustrated impurity filtering device is provided at an appropriate position.
Incidentally, as the positive displacement pump 7, a roots pump, a monopump, or the like is suitable. The flow straightening tube 8 is made of an elastically deformable material such as rubber. This rectifier tube 8
As shown in FIG. 2, both ends of the mounting flange 13 connected to the pipe line on the primary storage tank 6 side and the mounting flange 14 connected to the open-to-atmosphere pipe 9 are fitted. Then, the space between each of the mounting flanges 13 and 14 and the straightening pipe 8 is fastened and fixed by a hose band (not shown). In addition, the atmosphere opening pipe 9
Is to gradually increase the cross-sectional area from the inlet side 9a to the outlet side 9b as shown in FIG.

Here, the operation of each part of the defoaming apparatus having the above configuration will be described in the order in which the coolant is sent. The coolant is first stored in the primary storage tank 6 after being used for cooling the grinding tool and the workpiece in the grinding machine 4 and removing chips from the surface to be ground. The used coolant stored in the storage tank 6 is sucked and compressed by using a positive displacement pump 7.

By the way, the positive displacement pump 7 discharges fluid by changing or moving a sealed space formed between a casing and a rotor or the like which is a movable member inscribed therein (or between a cylinder and a piston). It generates pressure. Therefore, even when the coolant sucked from the suction port of the pump contains bubbles, the coolant and bubbles in the closed space are sent out to the discharge port while applying gentle pressurization to the coolant and bubbles, and the gradual addition of the coolant is performed. Defoaming can be performed by pressure.

The positive displacement pump surely sends a small amount of the coolant even if the ratio of the bubbles sucked into the closed space is larger than the ratio of the bubbles. It is possible. Therefore, the coolant can be reliably sent to the discharge port without greatly lowering the suction efficiency depending on the state of the bubbles contained in the coolant. In addition, since there is no operation of stirring the coolant inside the pump as in a turbo pump described later, foaming caused by the pump is at a level that can be almost ignored.

By the way, when a turbo type pump is used as this pump, the following problems occur. The turbo pump continuously accelerates a fluid in a pipeline by high-speed rotation of a turbine and generates a discharge pressure by kinetic energy generated in the fluid. In addition, in general, there is an advantage that a positive displacement pump can be small and can have a large head. However, the principle of its operation involves an unsuitable point for the pump of the defoaming device. Unlike a positive displacement pump, a turbo type pump always has a passage having a large sectional area between the suction port and the discharge port. Therefore, when the rotation of the turbine is stopped, not only the backflow occurs, but also when the ratio of the bubbles contained in the coolant is high, the suction efficiency is significantly reduced, and the specified pressure cannot be generated. In addition, the coolant sucked from the suction port by the high-speed rotation of the turbine is agitated, and further foaming occurs in the pump.

Although the positive displacement pump 7 is used in the present embodiment for the reasons described above, it does not depend on the components of the coolant liquid (the kind of the contained substance) and the state (amount and size) of the bubbles. Then, it goes without saying that a turbo pump can be used.

The coolant sucked and compressed by using the positive displacement pump 7 is sent to the straightening pipe 8 with pulsation from the discharge port of the pump. As described above, the rectifier tube 8
Is made of an elastically deformable material such as rubber, so that expansion and contraction, expansion and compression, etc., corresponding to the pressure fluctuation in the flow straightening tube 8 cancel out the pulsation of the coolant and can be sent to the atmosphere opening tube 9. If the flow straightening tube 8 is not elastically deformed, the inside of the flow straightening tube 8 will be in a negative pressure (vacuum) state when the flow rate is reduced due to the pulsation of the coolant, causing the coolant to bubble. Therefore, the rectifying tube 8 that can be elastically deformed has a great effect in preventing the bubbling of the coolant, especially when the positive displacement pump 7 is used. Further, even when a turbo pump is used, it is effective as a measure against surging.

Subsequently, the coolant pumped from the flow straightening pipe 8 to the open-to-atmosphere pipe 9 passes through the inside of the to-be-opened pipe 9 to its inlet side 9.
a, the pressure is smoothly reduced as it proceeds toward the exit side 9b,
Further, it is decelerated and poured into the secondary storage tank 10 while maintaining the defoaming state of the positive displacement pump 7. With the defoaming device described above, the coolant containing no air bubbles is stored in the secondary storage tank 10.

Then, the coolant in the secondary storage tank 10 is pumped up by the supply pump 11, passes through the supply pipe 12,
It is supplied to the grinding machine 4 again.

The functions and effects obtained from the embodiment of the present invention having the above-described configuration are summarized as follows. The used coolant stored in the primary storage tank 6 is defoamed by gentle pressurization in the positive displacement pump 7, and is further pumped from the discharge port with pulsation. The pulsation is canceled.
Then, the pressure is smoothly reduced and decelerated in the open-to-atmosphere pipe 9 and stored in the secondary storage tank 10 without foaming. Therefore, it is possible to always supply the coolant without foaming to the grinding machine 4.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of set values of each part for the above-mentioned defoaming device to exhibit a desired defoaming ability will be described below. Positive displacement pump 7
Is preferably 0.5 to ² kgf / cm ^2, but 0.2 to 30 kgf / cm ²
It can be used within the range of kgf / cm ² . In the example of FIG. 1, the displacement pressure is set to 0.5 kgf / cm ² and the discharge flow rate is set to 80 to 120 liters per minute by using a positive displacement pump 7 having a maximum discharge pressure of 3 kgf / cm ² and 1.5 kW. . The flow straightening tube 8 is made of material NBR (nitrile rubber), hardness 80, length 2
30mm (excluding length of fitting part with flanges 13 and 14), wall thickness 3
Use the one with mm. Here, the inner diameter of the flange 13 is 20φ,
The inner diameter of the flange 14 is 22φ.

[0022]

According to the present invention, the following effects are obtained. According to the defoaming device according to the first aspect of the present invention, in the coolant circulation path, an elastically deformable pipe is arranged in a path in which the coolant pressurizing means and the tank storing the coolant are connected. Thereby, the pulsation of the coolant flowing in the circulation path can be absorbed by expansion and contraction, expansion and compression of the elastically deformable conduit, and bubbling of the coolant can be prevented. Therefore, there is no need to use a filter element or remove a foaming agent to eliminate bubbles as in the conventional defoaming device, and high quality products can be obtained by using this device in the coolant circulation device of the processing device. It is possible to stably obtain, reduce the number of work steps related to the grinding device, and reduce industrial waste.

Further, according to the defoaming device of the present invention, by using a positive displacement pump as the pumping means, defoaming is performed by increasing the pressure of the coolant in the pump, and the pump is operated. Prevents the cause of coolant foaming. Further, the pulsation of the coolant at the discharge port can be canceled by the elastically deformable conduit, and the coolant in a defoamed state can be sent to the storage tank. Therefore, by using this apparatus for the coolant circulation device of the processing device, it is possible to stably obtain high-quality products, reduce the number of work steps related to the grinding device, and reduce industrial waste.

Further, according to the defoaming device of the third aspect of the present invention, by providing an open-to-atmosphere pipe at the outlet of the elastically deformable conduit, the defoamed high-pressure coolant is gently depressurized. And it can be sent to the storage tank while decelerating and maintaining the defoamed state. Therefore, the defoaming effect of the coolant is further enhanced, and it is possible to always supply the coolant without bubbles.

[Brief description of the drawings]

FIG. 1 includes a defoaming device according to an embodiment of the present invention.
It is a schematic diagram which shows the circulation path of a coolant.

FIG. 2 is a sectional view of a flow straightening tube used in the defoaming device of FIG.

FIG. 3 is a schematic diagram showing a conventional defoaming device.

[Explanation of symbols]

 4 Grinding machine 5 Coolant circulation path 6 Primary storage tank 7 Positive displacement pump 8 Straightening pipe 9 Open air pipe 10 Secondary storage tank 11 Supply pump 12 Supply pipe

Claims (3)

[Claims] 1. An anti-foaming apparatus characterized in that an elastically deformable pipe is arranged in a path in which a means for feeding a coolant and a tank for storing the coolant are connected in a coolant circulation path. apparatus. 2. A defoaming apparatus according to claim 1, wherein a positive displacement pump is used as said pumping means. 3. The defoaming device according to claim 1, wherein an air release pipe is provided at an outlet of the elastically deformable pipe.