JPH079417U - Gas purification filter - Google Patents

Abstract

(57) [Summary] [Purpose] A high-performance gas filter that can be used to purify exhaust gas containing mist. [Structure] A case 4 provided with a gas inlet 2 and a gas outlet 3, and a mist catcher 7 provided upstream in a gas flow path from the gas inlet to the gas outlet in the case.
And a filter medium 5 made of electret fiber provided on the downstream side. A baffle or a metal fiber layer can be preferably used for the mist catcher. Since the mist and a part of the solid particles are separated by the mist catcher, the contamination and separation load of the electret fiber filtering material are reduced, and the life thereof is extended. It is suitable for purifying the exhaust gas of a printer using toner.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a filter for purifying gas, and more particularly, to a gas purifying filter for purifying gas containing solid fine particles and mist, that is, fine liquid particles such as water, oil and tar.

[0002]

[Prior art]

 Conventionally, there are many filters that separate and remove fine particles contained in gas, but new high-performance filters are being developed from the viewpoint of environmental hygiene. For example, a filter for removing smoke and toner dust in an electronic image recording device (printer) is formed by stacking the electret fiber layer, which is a chargeable fiber, on the upstream side and the non-chargeable fiber layer on the downstream side. 63-264770) and the like.

[0003]

[Problems to be solved by the device]

 A gas purification filter that uses electret fiber (hereinafter referred to as electret fiber filter) has an electrical filtering action in addition to a mechanical filtering action, and efficiently separates solid fine particles in a gas down to the submicron class. Recently, OA equipment equipped with this in the exhaust passage has been well received. However, there is a problem that the life of the electret fiber filter is short depending on the mounting location, such as when it is mounted on a printer. Usually, electret fiber filters cannot be backwashed and reused, so if performance deteriorates, they must be replaced, and the cost was not negligible. The present invention has been completed with the object of solving the problems of such electret fiber filters and providing a gas purification filter that can be used for a long period of time.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention provides a case having a gas inlet and a gas outlet, and an upstream side in a gas flow path from the gas inlet to the gas outlet in the case. There is provided a gas purification filter comprising a mist catcher provided in the above and a filter material made of electret fiber provided on the downstream side. As the mist catcher, a baffle plate or a metal fiber layer can be preferably used here.

The electret fiber in the present invention refers to an electret formed into a substantially fibrous shape. In the production of electret fibers, usually, a method of electrostatically injecting electric charges in the production process of fibers (for example, described in JP-A-60-19970) or a high voltage is applied to a nonwoven fabric processed into a sheet shape. However, a method of injecting charges (for example, described in JP-A-61-102476) is used. When used in the gas purifying filter of the present invention, it is preferable that the ultrafine fiber nonwoven fabric is electretized and highly oriented and polarized, but the invention is not limited thereto. Also, different electret fibers or other fibers can be used together.

[0006]

[Action]

 The present inventor has sought to find out why an electret fiber filter attached to an OA device for purifying exhaust gas is easily contaminated, resulting in increased pressure loss and a short service life. It was found that most of them had a large amount of tar-like substances attached to the fiber surface. When exhaust gas containing a lot of fine liquid particles such as water, oil, and tar is treated with an electret fiber filter, the fine liquid particles adhere to the electret fibers and cover the surface, deteriorating the electrical collection performance. It has been found that the filter life is shortened by lowering the advanced filtration performance, or by rapidly increasing the fluid resistance. It was also found that this phenomenon was significant when the printer exhaust was treated.

Generally, an electret fiber filter installed in an OA device or the like has a case provided with a gas inlet and a gas outlet, and a gas flow path from the gas inlet to the gas outlet in the case. It is composed of a filter material made of electret fiber provided in the. The gas purification filter of the present invention is provided with a mist catcher on the upstream side of the electret fiber filter material attached to the conventional electret fiber filter. This mist catcher has a function of first separating and removing fine liquid particles such as water, oil and tar from the exhaust gas, and at the same time protecting the electret fiber. The filter medium made of electret fiber provided on the downstream side of the mist catcher has a function of removing solid fine particles remaining in the exhaust from which the fine liquid particles have been removed.

Here, the mist catcher is a separator mainly using an inertial force, which intercepts the exhaust flow path and changes the flow direction to collide mist with the mist catcher and collect them. , Baffles, or layers of metal fibers can be preferably used. Most of the mist in the exhaust gas collides with and adheres to the surface of the mist catcher to coagulate, and most of it is removed, and some of the solid particles also collide with the mist and adhere to be removed. The flow velocity of the exhaust gas reaching the mist catcher varies depending on the mass of the mist contained in the exhaust gas, etc., but in an OA device such as a printer using toner, it is generally about 2 to 5 m / sec. If it is too small, the mist separation efficiency decreases and the electret fibers are contaminated. If it is too large, the pressure loss increases and the equipment becomes too large, which is a problem. The electret fiber filter removes the remaining solid fine particles from the exhaust with a low mist content. The usage form of the electret fiber filter material can also be selected according to the type and performance of the filter material, the amount and type of mist contained in the exhaust gas, the particle size, the exhaust gas amount, and the like. As an example, an electret fiber filter material having a thickness of about 1 mm was bent into a saw blade shape having a height difference of about 20 mm, mounted on a printer, and processed at an exhaust flow rate of about 0.2 m / sec, and good results were obtained. However, this illustration is not meant to limit the invention.

In this way, the introduced exhaust gas is eventually purified through the two-step separation process. It should be noted that a layer of activated charcoal for deodorization, for example, may be further provided on the downstream side of the electret fiber filtration material to achieve a higher degree of purification such as removal of gaseous impurities. INDUSTRIAL APPLICABILITY The gas purification filter of the present invention is compact and can maintain the high performance of the electric fiber filter for a long period of time, and is suitable for being installed in the exhaust passage of the toner fixing zone of the printer.

[0010]

【Example】

 Embodiments of the filter of the present invention will be specifically described based on the drawings, but the present invention is not limited to these embodiments.

FIG. 1 is a perspective view of an embodiment of the gas purifying filter of the present invention, and FIG. 2 is a sectional view showing the AA ′ section of FIG. The filter 1 shown in FIGS. 1 and 2 is provided with a gas inlet 2 and a gas outlet 3, a cylindrical case 4 having both ends sealed with end plates, and a case 4 located inside the case 4 and a gas inlet. 2 is provided in the gas flow path from the gas outlet 3 to the gas outlet 3, and has a filter material (electret fiber layer) 5 supported on the outer periphery of a cylindrical wire mesh 6 in a folded state. A mist catcher (baffle plate) 7 is provided between the inlet port 2 and the filter medium 5 so that the exhaust gas flowing from the gas inlet port 2 collides and is separated. The mist catcher 7 is not particularly limited, but is preferably a metal plate, and the plate surface is preferably arranged at a position facing the exhaust gas flowing from the gas introduction port. A plurality of baffle plates including the gas inlet 2 may be provided according to the flow path, and the baffle plate may be used together with other types of mist catchers.

In the filter 1, the exhaust gas flowing in from the gas introduction port 2 first drastically changes its flow direction by the mist catcher 7. However, since the mist in the exhaust gas has a higher density than that of gas, the inertial force is large and the direction cannot be changed, so that the mist collides with the surface of the mist catcher 7, and is directly attached and separated. Some of the solid fine particles also collide with the surface of the mist catcher 7, and are trapped and separated by the mist components already attached. The diverted exhaust gas reaches the space between the case 4 and the filter medium 5, passes through the filter medium 5 to filter and separate the solid fine particles and the like, and passes through a wire mesh 6 holding the filter medium 5 to gas. It is discharged from the outlet 3 as purified gas. The thickness of the filter material 5 is not particularly limited, but is preferably 0.2 mm or more, more preferably 0.6 to 1.5 mm.

The mist adhering to the mist catcher 7 flows down through the mist catcher 7 and collects in the garter 8. If the amount of the mist is large, a liquid discharge port 9 is provided in the case 4 as shown in FIG. Can be discharged.

FIG. 3 is a cross-sectional view of a gas purification filter showing another embodiment of the present invention. The gas purifying filter 10 of FIG. 3 is provided with a mist catcher 11 made of, for example, a metal fiber layer or cotton-like fibers instead of the baffle plate mist catcher 7 shown in FIG. In this embodiment, the mist catcher 11 has a cylindrical shape and is provided so as to surround the filter medium 5 at a position slightly apart from the filter medium 5 so that aggregates of mist do not adhere to the filter medium 5.

In the filter 10, the exhaust gas that flows in from the gas inlet 2 flows into the space between the case 4 and the mist catcher 11, passes through the mist catcher 11, and reaches the electret fiber filter material 5. When passing through the mist catcher 11, the mist in the exhaust gas collides with and adheres to the metal fibers to be separated, and at the same time, some of the solid fine particles adhere to the liquid adhered to the metal fibers to be removed. The exhaust gas that has passed through the mist catcher 11 collects the remaining solid fine particles by the filter medium 5, and is discharged as purified gas from the gas discharge port 3 through the wire net 6 as described below with reference to FIG. The liquid adhering to the mist catcher 11 moves downward along the metal fibers and drops on the case 4. Therefore, it is preferable that the filter 10 is mounted vertically and used.

In these embodiments, the case has a cylindrical shape, and the gas inlet is provided on the side surface and the gas outlet is provided on the central shaft portion. However, the gas purification filter of the present invention has this shape. Not limited to For example, it is also possible to use a cylindrical or square tube-shaped case, take the gas flow path in the axial direction, and provide the mist catcher and the electret fiber filtration material in this order from the upstream side of the gas flow path.

As described above, the gas purifying filter of the present invention can be effectively used for exhaust gas containing mist and solid fine particles, and therefore, the exhaust gas purifying filter of a printer that fixes a toner image on recording paper. Is suitable as

[0018]

[Effect of device]

 In the gas purifying filter of the present invention, the mist unsuitable for the electric fiber filter material and some solid fine particles are separated and removed by the mist catcher provided between the gas inlet and the electric fiber filter material. The fibrous filter material is protected, mist does not adhere to it, and the filtration performance does not drop sharply. In addition to mist, some solid fine particles are removed, which can extend the service life, and Also, there is no sudden increase in fluid resistance. Therefore, the gas purifying filter of the present invention has an excellent effect that it can be used at a low cost with a low replacement frequency.

[Brief description of drawings]

FIG. 1 is a perspective view of a gas purification filter of the present invention.

FIG. 2 is a cross-sectional view showing the AA ′ cross section of the filter of FIG.

FIG. 3 is a cross-sectional view of a filter showing another embodiment of the present invention.

[Explanation of symbols]

1: Gas purification filter 2: Gas inlet 3: Gas outlet 4: Case 5: Filtering material 6:
Wire mesh 7: Mist catcher (baffle plate) 8: Garter
9: Liquid discharge port 10: Gas purification filter 11: Mist catcher (metal fiber layer)

Claims (3)

[Scope of utility model registration request] 1. A case provided with a gas inlet and a gas outlet, and a mist catcher provided in the case and on the upstream side in a gas flow path from the gas inlet to the gas outlet. A gas purification filter, characterized in that the gas purification filter is composed of a filtering material made of electret fiber provided on the downstream side. 2. The gas purifying filter according to claim 1, wherein the mist catcher is a baffle plate. 3. The gas purifying filter according to claim 1, wherein the mist catcher is a layer of metal fibers.