JP2899508B2 - Filtration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filtering device for filtering a liquid such as a working fluid or a lubricating oil for cutting in a machine tool by a filter element.

[0002]

2. Description of the Related Art For example, as a filtering method for filtering a machining fluid used for cutting in a machine tool, a metal chip contained in the machining fluid is removed by a magnet, and a filter is used regardless of a material to be machined. The processing fluid is filtered by the element, and further, the processing fluid and the chips are separated by a centrifugal separator.

[0003] As a method of filtering a machining fluid with a filter element, a machining fluid is circulated at high speed along the outer periphery of a cylindrical filter element, and the machining fluid which flows inside the filter element and is filtered is supplied to a machine tool. There is a so-called cross-flow filtration method.

[0004]

Depending on the cutting conditions and the material to be cut, the size and shape of the chips generated during processing are not uniform, and the fine elements tend to cause clogging of the filter element. Particularly, in recent years, in the field of semiconductor manufacturing, ceramics and the like, which are hard and brittle materials, are often processed by a slicing machine or an electric discharge machine, so that chips become finer and clogging of filter elements becomes severe.

Therefore, the Transactions of the Japan Society of Mechanical Engineers (B) 58
No. 546 (1992-2), an attempt to reduce clogging of a filter element by generating turbulent flow in a working fluid, as disclosed in the title of "Filtration of Working Fluid by Microfiltration Membrane". However, since a stirrer is used to cause a turbulent flow in the working fluid, a drive source for driving the stirrer is required, and the device is also large-scale.

[0006]

SUMMARY OF THE INVENTION A machine tool is provided between the outer cylinder and the inner cylinder by holding both ends of an outer cylinder and an inner cylinder having a large number of through holes at opposite flanges .
Form a liquid introduction flow path connected to the liquid outlet , along the longitudinal direction of the inner cylinder in contact with the inner surface of the inner cylinder
A cylindrical filter element having a predetermined length is inserted, and a liquid supply of the machine tool is inserted inside the filter element.
To form a liquid discharge flow path connected to the supply port, wherein the ends of the filter element to the inlet side of the fluid introducing passage
Do not reach the inner surface of the outer cylinder in the outer circumferential direction of the inner cylinder.
An annular resistor projecting at a high height was provided.

[0007]

A turbulent flow can be generated on the membrane surface of the filter element by the resistor, and foreign matter such as chips contained in the liquid is prevented from adhering to the filter element due to the turbulent flow. Clogging can be reduced. Moreover, since turbulence can be generated by a resistor that does not require a driving source, it is possible to reduce the size and cost of the device.

[0008]

An embodiment of the present invention will be described with reference to the drawings. First, an example of the filtration device 1 of the present invention is shown in FIG. Opposite flanges 2 and 3 hold both ends of outer cylinder 4 and inner cylinder 5. The inner cylinder 5 has a large number of through holes on the outer periphery, and a cylindrical filter element 6 is held on the inner surface. A liquid introduction passage 7 is formed between the outer cylinder 4 and the inner cylinder 5, and a liquid discharge passage 8 is formed inside the filter element 6. An annular resistor 9 is provided on the inlet side of the fluid introduction channel 7 so as to protrude from the end of the filter element 6 in the outer peripheral direction. Further, connection ports 10 and 11 connected to the liquid introduction flow path 7 are formed on the outer peripheral portions of the flanges 2 and 3, and a connection port 12 connected to the liquid discharge flow path 8 is formed at the center of the flange 3. .

Next, the mounting state of the filtration device 1 will be described. Reference numeral 13 denotes a machine tool such as a slicing machine. The machine tool 13 has a working fluid tank 14. The first tank 15 and the second tank 16 formed in the working fluid tank 14 are separated by a short partition plate 17.
Then, the liquid outlet 1 of the second tank 16 (machine tool 13)
Discharge line 1 connecting 3a and connection port 10 of filtration device 1
8, a pump 19, a valve 20, and a pressure gauge 21 are provided. A valve 23 is provided in a bypass pipe 22 branched from the discharge pipe 18 between the pump 19 and the valve 20 and opened to the upper part of the second tank 16. Further, the connection port 12 of the filtration device 1 and the machine tool 13
A valve 25 is provided in the supply pipe line 24 connecting the liquid supply port 13b of the above, and a valve 27 is provided in a circulation path 26 connecting the connection port 11 and the first tank 15. Further, a valve 27a for discharging a processing liquid 28 containing a large amount of impurities is connected to the bottom of the first tank 15.

In such a configuration, the working fluid 28 used during the cutting process is discharged to the first tank 15, but the chips 29 contained in the working fluid 28 settle at the bottom.
The level of the working fluid 28 in the first tank 15 is
Is exceeded, the working fluid 28 containing fine chips that are relatively clean but cannot be settled flows from the partition plate 17 into the second tank 16. The processing liquid 28 in the second tank 16 is pump 1
The processing liquid 28 sent to the liquid introduction channel 7 of the filtration device 1 by the filter element 9, filtered by the filter element 6 and flowing to the liquid discharge channel 8 is supplied to the liquid supply port 13 b of the machine tool 13. The working fluid 28 that does not pass through the filter element 6 is returned to the first tank 15 by the circulation path 26.

Here, the processing liquid 2 in the liquid introduction flow path 7
8 will be described. As indicated by an arrow in FIG. 2, since the working fluid 28 receives resistance from the resistor 9, a spiral turbulent flow is generated on the film surface of the filter element 6, and the turbulent flow is generated between the rectifying portion and the turbulent flow. A peel shear layer 30 is formed. Thereby, the turbulence of the flow of the working fluid 28 on the inner peripheral surface of the filter element 6 increases, and the generation of the cake layer is suppressed. That is, it is possible to prevent foreign matter such as fine chips contained in the working liquid 28 from adhering to the filter element 6. Thereby, clogging of the filter element 6 can be reduced.

Here, assuming that the height from the outer periphery of the filter element 6 to the inner periphery of the outer cylinder 4 is H and the height of the protrusion of the resistor 9 from the outer periphery of the filter element 6 is B, liquid introduction by the resistor 9 is performed. The closing rate C of the flow path 7 is represented by B / H. If B is increased, the turbulence of the working fluid 28 increases, but the pressure loss increases, which is disadvantageous for filtration. The results of the experiment are shown below.

Here, C: blockage ratio J: flux of the working fluid 28 permeating the filter element 6 (membrane permeation flux) V / AT m ³ / m ² / s V: working fluid permeating the filter element 6 Flow rate of 28 m ³ A: Cross-sectional area of filter element 6 m ² T: Filtration time s P: Differential pressure inside and outside filter element 6 (transmembrane pressure)
Pa Q: Circulating flow rate of working fluid 28 l / min Cb: Bulk (impurities such as chips) concentration of working fluid 28
Assuming g / liter, FIG. 3 shows the results of an experiment using the conventional configuration without the resistor 9, and FIGS. 4 and 5 show the results of the experiment with the configuration of the present invention in which the resistor 9 was installed. In each case, the vertical axis indicates the membrane permeation flux J, and the horizontal axis indicates the filtration time T.

First, consider FIG. The parameter is the bulk concentration Cb of the working fluid 28. In this case, as the filtration time T increases, the membrane permeation flux J decreases and approaches a constant value. The change in J accompanying the change in T is larger as T is in the initial stage. Also, the bulk concentration Cb
The J decreases as the condition increases. Under any conditions, T
At = 60 min, J has a constant value.

FIG. 4 shows Cb = 10 g / liter, and FIG.
b = 15 g / liter, and the blocking rate C is shown as a parameter in each case. 4 and 5, the membrane permeation flux J decreases as the filtration time T increases and approaches a constant value. The change in J with the change in T is
T is larger in the early stage. Further, under the conditions of FIGS. 4 and 5, J showed the maximum value when C = 0.45 regardless of the value of Cb.

[0016] Next, the filtration time T = 60min, the average membrane permeation flow relationship between the flux J _∞ and the closing rate C in the case of the the Cb parameters (experimental values and calculated values) in Fig. At a specific C, the average membrane permeation flux _J∞ shows a maximum value. This tendency is clearly shown as Cb is lower. That is, Cb
= 10 g / l and 12.5 g / l,
Although the C = 0.45 is J _∞ indicates a maximum value, Cb = 15 g / liter, the higher the 20 g / liter, say shows a maximum value average membrane permeation flux J _∞ in particular C The trend becomes less apparent. This is thought to be because when C becomes large, the turbulence of the working fluid 28 on the membrane surface of the filter element 6 becomes large, and it becomes difficult to form a cake layer, so that the membrane permeation flux increases.
On the other hand, when the resistor 9 is installed, a pressure loss occurs in the flow of the machining liquid 28, and the pressure (static pressure) acting on the membrane surface of the filter element 9 decreases as C increases,
It is believed that the membrane flux is reduced. For this reason, it is considered that an optimum closing ratio C exists according to the change in the bulk concentration Cb of the working fluid 28.

In the range of the Cb parameter selected in the experiment, a result was obtained in which the membrane permeation flux increased irrespective of the change in the value of the occlusion ratio C. Moreover, since turbulence can be generated by the resistor 9 that does not require a driving source, it is possible to reduce the size and cost of the device. Although the resistor 9 has been described as having an annular disk shape, the shape is not limited as long as it resists the flow of the working liquid 28. Further, the present invention is not limited to the use of filtering the working fluid 28, but is also applicable to the filtration of lubricating oil.

[0018]

According to the present invention, a liquid for a machine tool is held between the outer cylinder and the inner cylinder by holding both ends of the outer cylinder and the inner cylinder having a large number of through-holes at opposite flanges.
Forming a liquid introduction flow path connected to the discharge port, contacting the inner surface of the inner cylinder and predetermined along the longitudinal direction of the inner cylinder
A cylindrical filter element having a length is inserted, and a liquid supply port of the machine tool is inserted inside the filter element.
Forming a liquid discharge flow path connected to an inner side of the filter element at an inlet side of the fluid introduction flow path from an end of the filter element.
A height that does not reach the inner surface of the outer cylinder in the outer circumferential direction of the cylinder
Since the annular resistor protruding is provided, turbulence can be generated on the membrane surface of the filter element by the resistor, and foreign matter such as chips contained in the liquid adheres to the filter element due to the turbulence. Therefore, clogging of the filter element can be reduced, and turbulence can be generated by a resistor that does not require a driving source, thereby reducing the size and cost of the device. be able to.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of the present invention.

FIG. 2 is a partial vertical front view showing the operation of a resistor.

FIG. 3 is a graph showing a relationship between a filtration time and a membrane permeation flux using a bulk concentration in a working fluid as a parameter when a resistor is not installed.

FIG. 4 is a graph showing a relationship between a filtration time and a membrane permeation flux using a blockage rate by a resistor as a parameter.

FIG. 5 is a graph showing a relationship between a filtration time and a membrane permeation flux using a blocking rate by a resistor as a parameter.

FIG. 6 is a graph showing a relationship between a closing rate by a resistor and a membrane permeation flux using a bulk concentration in a working fluid as a parameter.

[Explanation of symbols]

 Reference Signs List 6 filter element 7 liquid introduction flow path 8 liquid discharge flow path 9 resistor 13 machine tool 13a liquid discharge port 13b liquid supply port

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B01D 35/02 B24B 55/03 B01D 61/00-71/82 B23Q 11/00

Claims (1)

(57) [Claims] At least two ends of an outer cylinder and an inner cylinder having a plurality of through-holes are held by opposed flanges to contact a liquid discharge port of a machine tool between the outer cylinder and the inner cylinder.
Forming a continuous liquid introduction flow path, and on the inner surface of the inner cylinder
Has a predetermined length along the longitudinal direction of the inner cylinder
A cylindrical filter element is inserted and connected to the liquid supply port of the machine tool inside the filter element.
That the liquid discharge flow path is formed, the fluid introduction flow path inlet side of the annular resistor from the end of the filter element projecting in the height does not reach the inner surface of the outer cylinder of the outer circumference of the inner cylinder A filtration device comprising: