JP3452983B2 - Filter element - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter element mounted on a filter for removing foreign matters such as water drops and solid matter in pressurized air or negative pressure air flowing in an air pressure control circuit.

[0002]

When operating an actuator such as a pneumatic cylinder, compressed air supplied from an air pressure source such as a compressor is actuated by using pneumatic equipment such as a pressure control valve, a directional control valve and a speed control valve. The air pressure control circuit is constituted by these.

Further, in an assembly line of parts and the like, an air pressure control circuit in which air having a pressure of atmospheric pressure or less, that is, negative pressure air is used as a working fluid is formed and, for example, negative pressure is used to adsorb parts. Negative pressure air is guided to the vacuum pad for this purpose. In such a case, a negative pressure source such as a vacuum pump or an ejector and a vacuum pad are connected by a pipe, and the pipe is provided with a directional control valve or the like for switching and controlling the flow of negative pressure air. ing.

Since foreign matter such as water droplets and solid matter is contained in the pressurized air and the negative pressure air as the working fluid flowing through the air pressure control circuit, a filter is used to remove them. Is attached to.

As a filter conventionally used for removing foreign matters contained in pressurized air, a filter container provided with blades and louvers, which are also called deflectors, is used. Is rotated along the inner peripheral surface of the filter container to remove foreign matters such as water droplets. There is also a filter element made of a sintered resin, a sintered metal, a wire mesh, or the like, provided near the outlet of the filter container.

[0006]

However, in the filter element having such a conventional structure, the foreign matter is captured by the pores formed in the filter element, but in the filter element such as the sintered resin, the pores are formed. There is a limit to the reduction of the inner diameter, and it is difficult to reliably remove foreign matter having a small diameter.

Therefore, the present inventor has studied the use of a porous hollow fiber filtration membrane having a hollow hole and a large number of pores for communicating the inner surface and the outer surface of the hollow hole as a filter element. did. The following is the technique examined by the present inventor, and the outline thereof is as follows.

That is, when a filter element in which a large number of porous hollow fiber filtration membranes are bundled is used, the average inner diameter of the pores formed in each porous hollow fiber filtration membrane is 0.1 μm.
It is possible to adjust the degree to a certain degree, and it is possible to remove foreign substances having a size larger than that. When a solid substance such as metal hits the outer surface of the filter element having such a filtration membrane, the filtration membrane is scratched and its life cannot be lengthened. We have developed a filter element in which the outside of the element body, which is formed into a rod shape as a whole, is covered with a porous sintered body.

In the case of forming a filter element having such a structure, an end portion of an element body formed by bundling a plurality of filtration membranes into a rod shape and a tubular member made of a porous sintered body for accommodating the end portion. Must be adhered to prevent air from leaking between the element body and the tubular member.

Therefore, an adhesive is applied between the outer peripheral surface of the end of the element body and the tubular member to bond them together, and the pores formed in the tubular member made of the porous sintered body are removed. A sealing treatment for filling is performed. However, it is conceivable that the adhesive may enter the pores of the tubular member to reliably bond the two, and air may leak from these gaps. In addition, there is a problem that it takes time to inspect the product.

An object of the present invention is to provide air from between a filter element body formed by bundling a large number of porous hollow fiber filtration membranes into a rod shape and a prefilter formed of a porous sintered body so as to cover the filter element body. To provide a high quality filter element.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0013]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

[0014] That is, the filter element of the present invention, a full <br/> I filter element body formed into a rod shape by bundling a large number of the porous hollow fiber filtration membrane aligned outlet opening of the respective hollow space , A pre-filter which is formed in a cylindrical shape by a porous sintered body and covers the outer periphery of the filter element body to filter the air flowing into the porous hollow fiber filtration membrane, and an adhesive on the outer peripheral surface of the end portion of the filter element body. And a ring-shaped adapter fixed to the pre-filter.

Further, in the filter element of the present invention, a large number of hydrophobic porous hollow fiber filtration membranes are arranged so that the outflow openings of the respective hollow holes are aligned at one end side, and a large number of hydrophilic porous hollow fiber filtration membranes are respectively formed. The filter element body formed into a rod shape by bundling the respective porous hollow fiber filtration membranes with the outflow openings of the hollow holes aligned with the other end side, and the filter element body formed into a cylindrical shape by a porous sintered body. A pre-filter that covers the outer periphery of the filter and filters air that flows into the hydrophobic porous hollow fiber filtration membrane, and a flat inner peripheral surface that is adhered to the outer peripheral surfaces of both ends of the filter element body with an adhesive.
An annular adapter fixed to the prefilter.

Furthermore the filter element of the present invention, the filter element body that is formed into a rod shape by bundling aligned large number of hydrophobic porous hollow fiber filtration membrane outlet openings of each hollow hole at one end, It is made of a porous sintered body having an opening at one end and a closing portion at the other end, and covers the outer periphery of the filter element body and the other end side to allow air flowing from the outer surface to the porous hollow fiber filtration membrane. It has a pre-filter for filtering, and a flat inner peripheral surface adhered to the outer peripheral surface of one end of the filter element body with an adhesive, and an adapter fixed to one end of the pre-filter.

[0017]

In the filter element having the above structure, the filter element body formed of the porous hollow fiber filtration membrane and the pre-filter made of the porous sintered body are fixed to each other through the adapter. A high quality air filter element can be obtained without air leaking from the outer peripheral portion of the element body.

Even when the air filter body is formed of a hydrophobic porous hollow fiber filtration membrane and a hydrophilic porous hollow fiber filtration membrane, the outer peripheral surface at both ends of the air filter body and the prefilter are Air leakage from the gap is prevented.

Further, even when the air filter element is formed of only the hydrophobic porous hollow fiber filtration membrane, the air leakage is similarly prevented.

[0020]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a view showing a filter having a filter element according to an embodiment of the present invention. This filter includes a resin case portion 2 having a filter chamber 1 therein, and a resin case portion 2. And a port block 3 to be assembled. The port block 3 is provided with a primary side port 4 connected to an air pressure source such as a compressor (not shown) via a pipe, and a secondary port connected to an actuator operated by pressurized air via a pipe. The side port 5 is formed. A drain discharge port 6 for discharging foreign matters such as water droplets to the outside is formed at the bottom of the case portion 2.

The primary port 4 communicates with the open end of the case 2 by a communication groove 7 formed in the port block 3, and the secondary port 5 has a communication hole formed in the center of the port block 3. It communicates with 8. The outside of the case portion 2 is covered with a cover 9, and the cover 9 is attached to the port block 3 by screwing a male screw portion 10 provided at an end of the case 9 and a female screw portion 11 provided on the port block 3 with each other. Has been.

A filter element 12 is mounted in the filter chamber 1 in the case portion 2. The filter element 12 has a cap 15 on the air outflow side having a male screw portion 14 screwed to a female screw portion 13 formed in the communication hole 8 and a protrusion 16 fitted into the drain discharge port 6.
And a cap 18 on the liquid discharge side in which a discharge hole 17 communicating with the drain discharge port 6 is formed. The cap 15 on the air outflow side is formed with a plurality of annular holes 19 communicating with the secondary port 5.

Between the caps 15 and 18, there is disposed a pre-filter 21 formed in a cylindrical shape by a porous sintered body made of a sintered resin or a sintered metal. This pre-filter 21 has pores that flow in from the outer surface and flow out to the inside, and its average inner diameter, that is, filtration accuracy, is approximately 5 μm.
m, which has a filtering function of preventing solids of a larger size from penetrating.

A filter element body 22 is incorporated in the cylindrical prefilter 21. As shown in FIGS. 1 and 2, the filter element body 22 includes a hydrophobic porous hollow fiber filtration membrane (hereinafter, simply referred to as a hydrophobic filtration membrane) 23 and a hydrophilic porous hollow fiber filtration membrane (hereinafter, simply referred to as a hydrophobic filtration membrane). (Referred to as a hydrophilic filtration membrane) 24. Hydrophobic and hydrophilic filtration membranes 23, 2 respectively
4 has a hollow hole 25, as shown in FIG.
It has a large number of pores 28 that connect 6 and the inner peripheral surface 27. The outer diameter D of each of the hydrophobic and hydrophilic filtration membranes 23 and 24 is about 0.38 mm, and the average inner diameter of the pores 28, that is, the filtration accuracy is about 0.1 μm.

The hydrophobic filtration membrane 23 is formed by folding a predetermined length into two and aligning the outflow openings 23a formed at both ends with the cap 15 on one end side of the filter element 12, that is, the air outflow side. And many books are bundled. Similarly, in the hydrophilic filtration membrane 24, the outflow openings 24a formed at both ends by bending the hydrophilic filtration membrane 24 into a shorter length than the hydrophobic one have the other end side of the filter element 12, that is, the liquid discharge side. A large number of them are bundled so as to be aligned with the cap 18. However, the length may be the same as that of the hydrophobic filtration membrane 23.

As shown in FIG. 2, a predetermined region 29 at the bent end of each of the filter membranes 23 and 24 is in a state in which both filter membranes 23 and 24 are mixed, and the filter element main body 22 as a whole. In general, the outer peripheral surface is formed in a rod shape having a substantially circular shape. The ends of the filtration membranes 23 and 24 on the opening side are fixed portions 23b and 24b.

Adapters 31 and 32 are adhered to the outer peripheral surfaces of both ends of the filter element body 22 via an adhesive agent 30. Each adapter 31, 32
Is made of resin or metal, has an inner peripheral surface that is flat, and has annular protrusions 33 and 34 on the outer peripheral surface.

A step portion 35 is provided on both caps 15 and 18.
36 are formed respectively, and step portions 37 and 38 are formed at both ends of the pre-filter 21. Each adapter 31, 32 is a step 35 of the cap 15, 18,
36 and the step portions 37 and 38 of the pre-filter 21 are fitted to each other, and the fitted portions are joined by an adhesive or welding using an ultrasonic welding machine or the like. FIG. 4 shows the adapter 31 and a part of the pre-filter 21 to which the adapter 31 is joined, but the diameter of the hydrophobic filtration membrane 23 is exaggerated.

When the filter having the above construction is provided in the pneumatic circuit, the pressurized air from the pneumatic pipe connected to the primary side port 4 flows into the filter chamber 1. When water drops are contained in the inflowing air, when the water drops come into contact with the hydrophobic filtration membrane 23, the contact angle of the water drops increases, and the water drops become hemispherical or spherical due to the surface tension. That is,
The hydrophobic filtration membrane 23 has a material having a small critical surface tension with respect to the surface of the water droplet, and is aggregated and rounded so that the surface area is minimized by the intermolecular attractive force of the water droplet.

Therefore, the water droplets do not enter the pores 28 of the hydrophobic filtration membrane 23, only the air flows into the pores 28, and the water droplets are separated by almost 100%. Then, the water droplets are repelled by the hydrophobic filtration membrane 23, and move toward the hydrophilic filtration membrane 24 so as to be attracted thereto. The hydrophilic filter membrane 24 has a critical surface tension close to that of water, and the contact angle with water is very small. Moreover, the hydrophilic filter membrane 24 passes through the pores 28 of the hydrophilic filter membrane 24 from the drain outlet 6. Since a slight flow of air to be discharged is formed, the water droplets are formed in the pores 28 of the hydrophilic filtration membrane 24.
Is discharged to the outside through.

In the illustrated case, since the filter element body 22 is formed by mixing the hydrophobic and hydrophilic filtration membranes 23 and 24, the water droplets repelled by the hydrophobic filtration membrane 23 Since the filter is attracted to the hydrophilic filtration membrane 24, the mounting posture of the filter is not limited to the vertical direction only, and can be any posture such as the horizontal direction or inclined walking.

Further, even if a solid substance or the like adheres to the outer surface of the hydrophobic filtration membrane 23, the water droplets that collide with the outer surface are repelled from the surface of the hydrophobic hydrophobic filtration membrane 23, and together with the repelled water droplets. Moreover, the solid matter is removed from the surface of the hydrophobic filtration membrane 23, and the occurrence of clogging on the surface of the hydrophilic filtration membrane 24 is prevented.

As described above, in the case portion 2 of the filter, the air flow from the primary side port 4 to the secondary side port 5 through the pores 28 of the hydrophobic filtration membrane 23 and the primary side port 4 flow. Along with the water droplets mixed in the air, the water reaches the drain discharge port 6, and a flow of air discharged from this is formed.

The air that has passed through the pre-filter 21 passes between these since the outer peripheral surface on one end side of the filter element main body 22 and the adapter 31 whose inner peripheral surface is flat are bonded by an adhesive. Without passing through the hydrophobic filtration membrane 24 and then reaches the secondary side port 5.

(Embodiment 2) FIG. 5 is a view showing a filter having a filter element 12a according to another embodiment of the present invention. This filter is used in an air pressure control circuit for supplying a negative pressure to a vacuum pad. A negative pressure source such as a negative pressure pump is connected to the negative pressure source side port 5a via a pipe, and a negative pressure actuating actuator such as a vacuum cup is connected to the suction side port 4a via a pipe. In FIG. 5, members common to the constituent members of the filter shown in FIG. 1 are designated by the same reference numerals.

The pre-filter 21a in this case is
It has an open end at one end and a closed end at the other end, and has a cup-shaped cross section with a bottom, and is formed of a porous sintered body as in the above embodiment. This pre-filter 21a is
It is fixed to the cap 15 via the adapter 31,
The filter element 12 a is housed in the filter chamber 1 by screwing the cap 15 to the port block 3.

In the case shown in FIG. 5, the filter element main body 22a is composed of only a large number of hydrophobic filtration membranes 23, and each hydrophobic filtration membrane 23 is folded in half and the outflow opening of the hollow hole 25. The filter element main body 22a is configured by bundling 23a so as to be aligned with one end side of the filter element main body 22a, that is, the cap 15 side.

Then, this filter element body 22
The outer peripheral surface of one end of a is bonded to the inner peripheral surface of the adapter 31 with an adhesive. Therefore, the suction side port 4a
After passing through the pre-filter 21a, the negative pressure air that has flowed in from does not leak between the hydrophobic filtration membrane 23 and the adapter 31 and flows to the negative pressure source side port 5a after passing through the hydrophobic filtration membrane 23. It will be.

The water droplets contained in the negative pressure air will collect on the bottom of the case portion 2. When a predetermined amount of water has accumulated, the cover 9 and the case portion 2 are removed and the water is discarded. To do. However, a valve that can be opened and closed may be provided at the bottom of the case portion 2 so that when the filter is not used, the valve is opened and the water is discarded to the outside.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, even when pressurized air is used as the working fluid as in the filter shown in FIG. 1, a filter of the type shown in FIG. It has a filter element main body composed of a prefilter composed of a bound body and a porous hollow fiber filtration membrane, and if it is fixed to the prefilter at the end of the filter element main body, for any type of filter The present invention can also be applied. The present invention can also be applied to a filter regulator in which a regulator that adjusts the pressure of the air flowing out from the secondary port is assembled in the port block.

[0043]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

(1). In the filter element having the filter element body and the pre-filter for filtering the air flowing therein, the filter element body and the pre-filter are attached via the adapter,
Adhesion between the prefilter and the filter element is improved.

(2) Therefore, air leakage does not occur between them, and a highly reliable and high quality filter element can be obtained.

(3) The filter element body can be fixed to the prefilter without sealing the pores formed in the prefilter made of the porous sintered body, and the fixed state can be easily confirmed. Therefore, the manufacturing work is facilitated, and as a result, the manufacturing cost is significantly reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a filter having a filter element according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a part of a filter element body.

FIG. 3 is an enlarged cross-sectional view showing a part of a porous hollow fiber filtration membrane.

FIG. 4 is a perspective view showing a joined state of an adapter and a filter element body.

FIG. 5 is a sectional view showing a filter having a filter element according to another embodiment of the present invention.

[Explanation of symbols]

1 filter room 2 Case part 3 port block 4 Primary port 4a Suction side port 5 Secondary port 5a Negative pressure source side port 6 Drain outlet 7 communication groove 8 communication holes 9 cover 10 Male thread 11 Female thread 12,12a Filter element 13 Female thread 14 Male thread 15 caps 16 Projection 17 Discharge hole 18 caps 21,21a pre-filter 22, 22a Filter element body 23 Hydrophobic porous hollow fiber filtration membrane (hydrophobic filtration membrane) 24 Hydrophilic porous hollow fiber filtration membrane (hydrophilic filtration membrane) 25 hollow holes 26 Outer surface 27 Inner surface 28 pores 30 adhesive 31,32 adapter 33, 34 protrusion 35-38 steps

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B01D 46/00-46/54 B01D 53/22 B01D 61/00-65/10

Claims (3)

(57) [Claims] And 1. A filter element body formed into a rod shape by a large number of the porous hollow fiber filtration membrane bundle align the outflow openings of each hollow bore is formed in a cylindrical shape by a porous sintered body And a pre-filter that covers the outer periphery of the filter element body and filters air that flows into the porous hollow fiber filtration membrane, and a flat inner peripheral surface that is adhered by an adhesive to the outer peripheral surface of the end portion of the filter element body. the a, <br/> filter element and having an annular adapter secured to the pre-filter. 2. A large number of hydrophobic porous hollow fiber filtration membranes are aligned with the outflow openings of the respective hollow holes at one end side, and a large number of hydrophilic porous hollow fiber filtration membranes are connected to the outflow openings of the respective hollow holes. A filter element main body formed in a rod shape by bundling the respective porous hollow fiber filtration membranes aligned with the other end side, and formed in a tubular shape by a porous sintered body, and covering the outer periphery of the filter element main body. A prefilter for filtering the air flowing into the hydrophobic porous hollow fiber filtration membrane, and a flat inner peripheral surface that is adhered to the outer peripheral surfaces of both ends of the filter element body with an adhesive, and is fixed to the prefilter. And a ring-shaped adaptor. 3. A large number of hydrophobic porous hollow fiber filtration membrane and filter element body formed into a rod shape by bundling outlet opening of each hollow bore aligned at one end, an opening at one end Yes A pre-filter that is formed of a porous sintered body having a closed portion at the other end and covers the outer circumference and the other end side of the filter element body to filter the air flowing from the outer surface into the porous hollow fiber filtration membrane. And a flat inner peripheral surface adhered to the outer peripheral surface of one end of the filter element body by an adhesive, and an adapter fixed to one end of the prefilter.