JP7759062B2 - Coolant tank and circulation device equipped with the coolant tank - Google Patents

Description

The present invention relates to a coolant tank for storing coolant liquid used in machine tools, etc., particularly a coolant tank that stores both unfiltered and filtered coolant liquid, and a circulation device equipped with a coolant tank.

Conventionally, machine tools use coolant, also known as cutting oil or grinding oil. Because coolant is used not only for cooling and lubrication but also for cleaning purposes, used coolant becomes contaminated with particulate solid matter such as cutting and grinding chips (hereafter referred to as sludge). This coolant is generally reused through a circulation system, but using coolant containing sludge can affect cutting and other processes, so the sludge must be removed from used coolant. Such circulation systems typically use coolant tanks to store both unfiltered and filtered coolant.

Figure 6 is a schematic diagram of a system consisting of a machine tool 100 and a circulation device 200. As shown in the figure, the circulation device 200 is provided with a coolant tank 210, which in turn comprises a dirty tank 211 and a clean tank 212. Used coolant containing sludge flows into the dirty tank 211 through flow path 201. The coolant that flows into the dirty tank 211 is supplied to the filtration device 204 via flow path 203 by pump 202. The filtration device 204 filters the sludge from the coolant, and the coolant from which the sludge has been removed flows into the clean tank 212 via flow path 205. The coolant that flows into the clean tank 212 is supplied again to the machine tool 100 via flow path 207 by pump 206.

In such a circulation device 200, if the amount of coolant discharged to the filtration device 204 decreases due to, for example, a malfunction or performance degradation of the pump 202, or clogging of the flow path 203, there is a risk of coolant overflowing from the dirty tank 211.

To prevent coolant from overflowing from such a dirty tank, for example, Patent Document 1 discloses a coolant tank in which a primary tank (dirty tank) and a secondary tank (clean tank) are arranged adjacent to each other, with a communication part provided in the gas phase area above them. In the device disclosed in Patent Document 1, when the amount of coolant in the primary tank increases, the coolant from the primary tank flows into the secondary tank through this communication part, preventing coolant from overflowing from the primary tank.

In addition, there is a demand for coolant tanks to be able to store a larger amount of coolant liquid, from the perspective of cooling performance and sludge removal capacity. In order to increase the amount of coolant liquid stored, the volume of the clean tank can be increased, and this can be achieved by increasing the installation area or height of the clean tank, or both.

International Publication No. WO2019/058719 Pamphlet

Increasing the installation area to increase the amount of coolant stored is not desirable from the perspective of efficient use of the machine tools and coolant tanks in the factory where they are installed. On the other hand, increasing the height of the coolant tank can also cause problems. Generally, coolant is supplied from the machine tool to the coolant tank via a difference in elevation. Therefore, if the height of the coolant tank is increased, it will be necessary to create a difference in elevation between the machine tool and the coolant tank by installing the machine tool at a higher elevation or by burying the coolant tank, making installation more difficult.

In order to increase the amount of coolant stored while maintaining the height difference between the machine tool and the coolant tank (especially the dirty tank), one option is to increase the volume of the clean tank. However, since it is not desirable to increase the installation area of the clean tank, it is preferable to increase the height of the clean tank.

If this is applied to the coolant tank of Patent Document 1, it will be possible to solve both the problems of preventing coolant from overflowing from the dirty tank and increasing the amount of coolant stored. However, with the coolant tank of Patent Document 1, a communication part must be provided in the gas phase region between the dirty tank and the clean tank, so the height of the dirty tank and the height of the clean tank must be approximately the same. In other words, with the coolant tank of Patent Document 1, it is not possible to change the height of the clean tank alone.

In other words, conventional technology was unable to solve the two problems of preventing coolant from overflowing from the dirty tank and increasing the amount of coolant stored.

The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a coolant tank and a circulation device equipped with a coolant tank that has a simple configuration but prevents coolant from overflowing from the dirty tank and can increase the amount of coolant stored without increasing the installation area.

In order to solve the above problems, the present invention provides a coolant tank including a dirty tank that stores pre-filtered coolant, which is coolant before filtering, and a clean tank that stores filtered coolant obtained by filtering the pre-filtered coolant. The clean tank includes a first clean tank into which the filtered coolant flows, a second clean tank into which the filtered coolant flows from the first clean tank, and a flow path for flowing the filtered coolant from the first clean tank to the second clean tank. The height of the first clean tank is greater than the height of the dirty tank and the height of the second clean tank. The dirty tank and the second clean tank are adjacently disposed with a partition wall between them. A communication part that communicates the dirty tank and the second clean tank to allow the coolant to overflow is provided in the partition wall . The first clean tank and the second clean tank are separated so as not to communicate with each other internally. The first clean tank has an outlet part that discharges the filtered coolant toward the flow path, at a position higher than the top surface of the second clean tank .

In this configuration, the clean tank is made up of a second clean tank and a higher first clean tank. This allows the volume of the coolant tank, particularly the clean tank, to be increased without increasing the installation area. Furthermore, a communication section is formed in the partition between the dirty tank and the second clean tank. Therefore, if the coolant level in the dirty tank increases due to a malfunction or other reason, the coolant flows through the communication section and into the second clean tank. This prevents the coolant from overflowing from the dirty tank.

Filtered coolant flows into the first clean tank, but there is a possibility that some sludge remains in the filtered coolant. Because the specific gravity of this sludge is greater than that of the coolant, it is believed to settle or float near the bottom of the first clean tank. In other words, the upper part of the first clean tank contains less sludge than the lower part. Therefore, with this configuration, the coolant in the upper part of the first clean tank, i.e., the cleaner coolant with less sludge, can flow into the second clean tank.

The present invention also encompasses a circulation device comprising the above-mentioned coolant tank and a filtration device that filters the coolant liquid. Such a circulation device comprises a first pump for flowing the unfiltered coolant liquid from the dirty tank to the filtration device, and a second pump for discharging the filtered coolant liquid from the second clean tank, and the discharge volume of the first pump is greater than the discharge volume of the second pump.

In the coolant tank of the present invention, the dirty tank and the second clean tank are connected via a communication section, which means that there is a risk that the unfiltered coolant liquid in the dirty tank, which contains a large amount of sludge, will flow into the second clean tank. However, with this configuration, the coolant liquid in the second coolant tank normally always flows into the dirty tank, preventing the unfiltered coolant liquid from mixing with the filtered coolant liquid in the second clean tank.

1 is a simplified diagram of a machine tool and a circulation device including a coolant tank according to the present invention; FIG. 2 is a schematic perspective view of a coolant tank. FIG. 3 is a cross-sectional perspective view taken along the line III-III in FIG. 2. FIG. 6 is a cross-sectional perspective view taken along the line VI-VI in FIG. 2. FIG. 3 is a cross-sectional perspective view taken along the line VV in FIG. 2. 1 is a simplified diagram of a machine tool and a circulation system with a prior art coolant tank.

The following describes an embodiment of a coolant tank according to the present invention using the drawings. Figure 1 is a simplified diagram of a machine tool A that performs cutting, grinding, etc., and a circulation device B that circulates coolant liquid for cleaning, cooling, and lubricating the machine tool A.

The circulation device B includes flow paths a1, a2, c1, and c2 for flowing the coolant, a coolant tank 1 according to the present invention for storing the coolant, a filtration device C for filtering sludge from the coolant, and a first pump P1 and a second pump P2 for circulating the coolant. The filtration device C can be, for example, the filter device disclosed in Japanese Patent Application Laid-Open No. 2023-025359.

As described below, the coolant tank 1 comprises a dirty tank 2 that stores coolant containing sludge (unfiltered coolant), and a clean tank 3 that stores coolant from which sludge has been filtered by the filtration device C (filtered coolant).

Flow path a1 is used to supply used coolant (unfiltered coolant) from machine tool A to dirty tank 2. Flow path c1 is used to supply unfiltered coolant from dirty tank 2 to filtration device C using the first pump P1. Flow path c2 is used to supply coolant (filtered coolant) from which sludge has been filtered by filtration device C, from filtration device C to clean tank 3. Flow path a2 is used to supply coolant from clean tank 3 again to machine tool A using the second pump P2.

Figure 2 is a schematic perspective view of the coolant tank 1 in this embodiment. As shown in the figure, the coolant tank 1 includes a dirty tank 2 that stores unfiltered coolant liquid containing sludge, and a clean tank 3 that stores filtered coolant liquid. The clean tank 3 includes a first clean tank 31 and a second clean tank 32. In this embodiment, the dirty tank 2, first clean tank 31, and second clean tank 32 are each formed in a hollow rectangular parallelepiped shape, and the first clean tank and second clean tank 32 are arranged adjacent to each other. Furthermore, both the first clean tank 31 and the second clean tank 32 are arranged adjacent to the dirty tank 2.

A pipe ap1 is connected to the top surface of the dirty tank 2. Unfiltered coolant from machine tool A flows into the dirty tank 2 through a flow path a1 within this pipe ap1. One end of a pipe cp1 also penetrates the top surface of the dirty tank 2, and the other end of the pipe cp1 is connected to the filtration device C. Unfiltered coolant within the dirty tank 2 is supplied to the filtration device C through a flow path c1 within this pipe cp1.

Meanwhile, pipe cp2 extends from the filter C to the first clean tank 31. After sludge has been filtered by the filter C, the filtered coolant flows into the first clean tank 31 through flow path c2 within pipe cp2.

An L-shaped pipe 33 is installed from the side wall of the first clean tank 31 to the top surface of the second clean tank 32. The L-shaped pipe 33 is hollow and has a flow path 33a (an example of a flow path in the present invention) formed inside it, and the coolant liquid in the first clean tank 31 flows into the second clean tank 32 through this flow path 33a.

A pipe ap2 penetrates the top surface of the second clean tank 32. The coolant in the second clean tank 32 is supplied to the machine tool A through a flow path a2 in this pipe ap2, where it is used again for cleaning, cooling, lubrication, etc.

Note that circulation device B is equipped with a magnetic separator to remove magnetic material and a cooling device to cool the coolant liquid, but these are not shown or described here.

The coolant tank 1 according to this embodiment of the present invention will be described in detail below using Figures 2 to 5. Figures 3 to 5 are perspective cross-sectional views taken along lines III-III, IV-IV, and V-V in Figure 2, respectively, but do not include the first pump P1 and second pump P2.

The coolant tank 1 is arranged so that it is rectangular when viewed from above, with half of its width being the dirty tank 2 and the other half being the clean tank 3. However, as shown in Figure 2, they have different heights. Specifically, the dirty tank 2 and the second clean tank 32 are the same height, but the first clean tank 31 is higher than them. In this way, by partially raising the clean tank 3, it is possible to increase the capacity of the coolant tank 1, particularly the clean tank 3, and increase the amount of coolant liquid that can be stored.

As shown in FIG. 3, the side wall of the first clean tank 31 facing the second clean tank 32 has an opening 31a (corresponding to the outflow portion in this invention) cut out in a rectangular shape from the top end. The shape of this opening 31a is designed to match the outer shape of the end of the L-shaped pipe 33 facing the first clean tank 31. As a result, coolant liquid overflowing from the first clean tank 31 flows out from the opening 31a and passes through the flow path 33a into the second clean tank 32.

The first clean tank 31 receives filtered coolant, which has had sludge filtered out by the filtration device C, but there is a possibility that some sludge may remain in the filtered coolant. Because sludge generally has a greater specific gravity than coolant, the sludge settles or floats near the bottom in the first clean tank 31. Therefore, it is believed that there is less sludge in the upper part of the coolant in the first clean tank 31. Therefore, by overflowing the coolant from near the top end of the first clean tank 31, cleaner coolant can be supplied to the second clean tank 32 and further to the machine tool A.

As shown in Figures 2 and 4, the wall surface of the dirty tank 2 on the clean tank 3 side (corresponding to the partition wall in this invention) has a rectangular opening cut out from the top end in the portion facing the second clean tank 32. Meanwhile, the wall surface of the second clean tank 32 on the dirty tank 2 side (corresponding to the partition wall in this invention) also has a rectangular opening cut out from the top end. These openings have the same shape and are formed in opposing positions, forming a communication section 4. In other words, the dirty tank 2 and the second clean tank 32 are in communication via the communication section 4.

Next, we will explain the flow of coolant under normal conditions (represented by dotted arrows in Figure 2). Coolant used by machine tool A flows into dirty tank 2 through pipe ap1. The coolant in dirty tank 2 is supplied to filtration device C via pipe cp1 by first pump P1. In filtration device C, sludge is filtered from the coolant, and after filtration, the coolant flows into first clean tank 31 through pipe cp2.

When the coolant level in the first clean tank 31 exceeds the lower end of the opening 31a, the coolant overflows from the opening 31a and flows through the flow path 33a into the second clean tank 32. As mentioned above, any sludge remaining in the coolant after filtration settles or floats near the bottom in the first clean tank 31, so the coolant that overflows from the first clean tank 31 contains even less sludge and other residue.

The coolant in the second clean tank 32 is supplied again to the machine tool A through pipe ap2 by the second pump P2.

In this embodiment, the discharge rate of the first pump P1 is set to be greater than the discharge rate of the second pump P2. By setting the pump discharge rates in this way, the amount of coolant flowing into the clean tank 3 is greater than the amount of coolant flowing out of the clean tank 3, allowing a sufficient amount of coolant to be stored in the clean tank 3 and preventing the coolant from running out.

In addition, in the coolant tank 1 according to the present invention, the dirty tank 2 and the second clean tank 32 are connected via the communication section 4, which may cause unfiltered coolant in the dirty tank 2 to flow into the second clean tank 32. However, this problem can be solved by setting the pump discharge rate as described above. Specifically, overflow from the second clean tank 32 occurs due to the difference between the amount of coolant flowing into the clean tank 3 and the amount of coolant flowing out of the clean tank 3. This coolant overflowing from the second clean tank 32 flows into the dirty tank 2 via the communication section 4. In other words, in this embodiment, there is always a flow from the second clean tank 32 to the dirty tank 2 under normal circumstances. This prevents unfiltered coolant from flowing into the clean tank 3, even when the dirty tank 2 and the second clean tank 32 are connected via the communication section 4.

On the other hand, if the discharge rate of the first pump P1 decreases due to a malfunction of the first pump P1 or other reasons, the amount of coolant stored in the dirty tank 2 increases and the amount of coolant stored in the clean tank 3 decreases. In this case, coolant flows from the dirty tank 2 to the second clean tank 32 via the communication part 4. This prevents coolant from overflowing from the dirty tank 2. However, because there is a limit to the amount of coolant that can be stored in the clean tank 3, in such a case it is necessary to immediately shut down the device and stop the circulation of coolant.

In this way, in the present invention, by providing a communication section 4 between the dirty tank 2 and the clean tank 3, if the amount of coolant in the dirty tank 2 increases abnormally, the coolant in the dirty tank 2 can be released into the clean tank 3 via the communication section 4, preventing the coolant from overflowing from the dirty tank 2. Furthermore, by raising a portion of the clean tank 3, the overall amount of coolant stored in the clean tank 3 can be increased. In other words, the coolant tank 1 of the present invention prevents the coolant from overflowing from the dirty tank 2 and increases the amount of coolant stored in the clean tank 3 without increasing the installation area.

[Another embodiment]
(1) In the above embodiment, the clean tank 3 is composed of the first clean tank 31 and the second clean tank 32, which are separated from each other. However, the first clean tank 31 and the second clean tank 32 may be integrally formed. In this case, the external L-shaped pipe 33 (flow path 33a) is not necessary. In this case, a partition wall separating the first clean tank 31 and the second clean tank 32 may or may not be provided inside the clean tank 3. In the former case, a partition wall separating the first clean tank 31 and the second clean tank 32 is provided in the partition wall, and an opening serving as the flow path 33a is formed in the partition wall. On the other hand, in the latter case, the entire boundary between the first clean tank 31 and the second clean tank 32 serves as the flow path 33a. In the latter case, although the effect of sludge settling in the first clean tank 31 cannot be expected, the original object of the present invention can be achieved.

(2) In the above embodiment, the dirty tank 2, first clean tank 31, and second clean tank 32 are each formed as adjacent hollow rectangular parallelepiped members, but they may also be formed integrally with partitions separating them.

(3) In the above embodiment, the first clean tank 31 and the second clean tank 32 are arranged adjacent to each other, but they may also be arranged at a distance from each other.

(4) In the above embodiment, the coolant liquid is allowed to overflow from the first clean tank 31 and flow into the second clean tank 32, but a pump or the like may also be used.

(5) In the above embodiment, the flow path a1 was formed using the pipe ap1 to supply the coolant from the machine tool A to the dirty tank 2, but a member of another shape, such as a trough-shaped member, may be used instead of the pipe ap1. Furthermore, the coolant may be dropped from the machine tool A into the opening of the dirty tank 2 without using these members.

The present invention can be used in coolant tanks for storing coolant used in machine tools, as well as coolant that is filtered after use and reused; specifically, coolant tanks that store both pre-filtered and filtered coolant.

A: Machine tool B: Circulation device C: Filtration device P1: First pump P2: Second pump 1: Coolant tank 2: Dirty tank 3: Clean tank 31: First clean tank 31a: Opening (outlet portion)
32: Second clean tank 33: L-shaped pipe 33a: Flow path 4: Communication section

Claims (2)

a dirty tank for storing pre-filtered coolant liquid, which is coolant liquid before filtering; and a clean tank for storing filtered coolant liquid obtained by filtering the pre-filtered coolant liquid;
A coolant tank comprising:
The clean tank is
a first clean tank into which the filtered coolant flows;
a second clean tank into which the filtered coolant liquid flows from the first clean tank;
a flow path for allowing the filtered coolant liquid to flow from the first clean tank to the second clean tank,
The height of the first clean tank is formed higher than the height of the dirty tank and the height of the second clean tank,
The dirty tank and the second clean tank are disposed adjacent to each other with a partition wall therebetween,
a communication portion that communicates the dirty tank with the second clean tank and allows the coolant liquid to overflow is provided in the partition wall ;
the first clean tank and the second clean tank are separated from each other so as not to communicate with each other internally,
A coolant tank in which an outflow portion for causing the filtered coolant liquid to flow out toward the flow path is formed at a position of the first clean tank above an upper surface of the second clean tank . 2. A circulation system comprising the coolant tank according to claim 1 and a filtration device that filters the coolant liquid,
a first pump for causing the unfiltered coolant liquid to flow from the dirty tank to the filtering device;
a second pump for discharging the filtered coolant from the second clean tank,
A circulation device in which the discharge volume of the first pump is greater than the discharge volume of the second pump.