JP2002355513A - Felt filter with density adjusting function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a felt filter which is made adjustable in fiber filling density in accordance with the filtration state of the filter. SOLUTION: This felt filter with density adjusting function comprises a measuring means (pressure gauge 9 or electrode 18) which measures flow resistance of a fluid passing through the felt filters A, B which are laminated at random without sticking fiber 2 or 3 by itself, a fluid flow rate monitoring means (rotating sensor 10 and fuel flow rate meter 12) and a fiber packing density adjusting means (solenoid valve 9) of the felt filters A, B. Therein, the filling density adjusting means is actuated in accordance with detecting signals which are outputted by the measuring means and the monitoring means, and the filling density of fiber of the felt filters A, B is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a felt filter having a density adjusting function, and more particularly, to a filter capable of adjusting a fiber density in a felt filter for repairing particulate matter suspended in a gas. It is something you can do.

[0002]

2. Description of the Related Art For example, the exhaust gas of a diesel engine contains particulate matter harmful to the human body. As a filter for removing the particulate matter, a felt made of heat-resistant fibers such as silicon carbide is randomly laminated. It is well known that the development of a filter in the shape of a filter is underway.

[0003]

However, since the conventional felt-like filter is used at a fixed packing density,
It has been conventionally performed to change the density by changing the fiber diameter or the filling amount in accordance with the filtration conditions. However, even with the same filter, the filtration rate (collection rate) of the filter changes in the filtration state. Especially low filtration rate at the beginning of use,
On the other hand, if the initial filtration rate is improved by increasing the packing density of the fibers, there is a problem that clogging occurs quickly and the usable time is shortened.

The present invention has been made in view of the above problems, and has as its object to provide a felt-like filter in which the packing density can be adjusted according to the filtration state of the filter.

[0005]

To achieve the above object, a felt filter having a density adjusting function is a felt filter in which fibers are laminated at random without adhering to each other, a flow resistance of a fluid passing through the filter. Measuring means, a fluid flow rate monitoring means passing through a filter, and a filling density adjusting means for the fibers of the felt-like filter, and the detecting means output by the measuring means and the monitoring means actuates the filling density adjusting means. The fiber filling density of the felt-like filter is adjusted.

The adjusting means is not particularly limited. For example, there are provided a valve provided before, after or before or after the filter and means constituted by the valve driving means, an electrode provided around the filter, and an electrostatic charge applied to the electrode. Means such as pressure adjusting means can be used.

The object to be filtered by the filter is not particularly limited, and the present invention can be applied to any fluid in which particulate matter is suspended, especially any gas. For example, it can be used as an exhaust gas purification device for a diesel engine.

[0008] The material of the fiber used for the filter is
There is no particular limitation except that the material can be fiberized and is physically and chemically stable during use as a filter. For example, when used for removing particulate matter in diesel engine exhaust gas, the fiber material must have heat resistance, such as ceramics such as silicon carbide, mullite, alumina, and silica, and iron-chromium. An aluminum-based metal wire or the like can be used.

There is no particular limitation on the electrode, and any electrode which exerts an electrostatic force for coagulating fibers, such as a mesh electrode or an electrode wire, can be used. The flow rate monitoring means is not particularly limited. For example, when the fluid to be processed is diesel engine exhaust gas, the processing is performed by means for calculating the amount of exhaust gas from the engine speed, fuel flow rate, etc.
Appropriate means can be adopted according to the actual situation.

When the collected particulate matter is flammable, an oxidation catalyst is supported on the fibers, the collected particulate matter is removed by combustion, and the clogged filter is regenerated to regenerate the clogged filter. It can be used as a carrier.

There is no particular limitation on the fiber diameter when using the above-mentioned ceramic fiber or metal wire, and a fiber diameter suitable for the size of the particulate matter to be collected can be used. When used also as a catalyst carrier, the fiber diameter may be, for example, 6 to 18 μm. If the thickness is less than 6 μm, there is a concern that the effect on the human body may be caused.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to an embodiment with reference to the accompanying drawings. The felt-like filter 1 of the first embodiment shown in FIGS. 1 and 2 is obtained by laminating silicon carbide fibers 2 each having a fiber diameter of 9 μm at random without being fixed to each other, and needling (not shown). Felt (non-woven) filter A, fiber diameter 14 μm
Are randomly laminated without being fixed to each other, and are subjected to needling (not shown) to obtain a felt-like (non-woven) filter B. 4 are superimposed to form a filter module.

Then, the felt-like filter A is installed in the particulate matter purification device (DPF: FIG. 2) 5 so as to be on the upstream side (inflow side) of the inflowing exhaust gas (open arrow in FIG. 1). As shown in FIG. 2, an exhaust passage 8 is provided between an exhaust manifold 7 of a diesel engine 6 and a muffler (not shown).

As a measuring means for measuring the flow resistance according to the first embodiment, a pressure gauge 9 is connected to the exhaust passage 8 downstream of the DPF 5.
, And a pressure gauge 10 was attached downstream thereof. The means for monitoring the flow rate of the fluid passing through the filter 1 (FIG. 1) comprises a rotation sensor 10 attached to the engine 6 and a fuel flow meter 12 interposed in a fuel passage 11. The solenoid valve 14 is controlled by attaching the exhaust gas passage 8 to the exhaust passage 8.

A computer (not shown) incorporated in the control device 13 calculates the exhaust gas outflow amount from the detection signals from the rotation sensor 10 and the fuel flow meter 12. Reference numeral 15 shown in FIG.
Reference numeral 6 denotes a fuel tank, and 17 denotes an intake manifold.

As a comparative example, a filter in which the DPF 5 was simply attached and the valve 14 and the control device 13 were omitted was prepared.
Was measured.

The filter 1 according to the first embodiment is used when the exhaust pressure is relatively low at the initial stage of particulate matter collection and when the engine 6 is started, or when the amount of particulate matter PM increases. In such a case, the valve 14 was forcibly throttled, and the density of the felt-like filter A of the filter 1 was increased from the normal state shown in FIG. 3 to the state shown in FIG. As a result, the particulate matter PM purification rate (filtration rate) was 95% on average, and at least 90% or more. In contrast, the purification rate of Comparative Example 1 was 90% on average and 80% at the minimum.

A felt-like filter (not shown) according to the second embodiment shown in FIG. 5 was the same as that shown in FIG. A mesh electrode and an electrode 18 of an electrode wire are provided on the exhaust gas upstream side of the DPF 5 (in front of the filter A) and in the filter, and a DC voltage of 0.5 to 10 kV can be applied thereto by the control device 13.
Except where 4 was omitted, it was attached to the diesel engine 6 as in the first embodiment.

The apparatus of the comparative example was used as a comparative example in the second embodiment. As in the case of the first embodiment, when the back pressure is relatively low in the early stage of collection and at the time of start, or at a horsepower point where the amount of particulate matter PM is large, an electric field is applied to the electrode 18 to filter. The control for increasing the density of No. 1 was performed. As a result, the particulate matter purification rate was 95% on average, and at least 90% or more. In contrast, the particulate matter purification rate of the comparative example was 90% on average and 8% at minimum.
It was 0%.

[0020]

As described above, the felt filter with the density adjusting function of the present invention is capable of adjusting the fiber packing density of the filter to be high when a high filtration rate (collection rate) is required.
If the filtration rate increases and the collection rate increases, the density of the filter can be adjusted to a low level to provide a felt (nonwoven) filter with a high collection rate and a long collection time, thereby improving the reliability of the filter. Was completed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a cross section of a felt filter with a density adjusting function according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state in which a particulate matter purification device (DPF) equipped with a felt filter with a density adjusting function shown in FIG. 1 is attached to a diesel engine.

FIG. 3 is an enlarged cross-sectional view schematically showing a state of a felt filter having a density adjusting function shown in FIG. 1 at a normal packing density.

FIG. 4 is a cross-sectional view schematically showing a state in which the packing density of the felt filter with a density adjusting function shown in FIG. 3 is increased.

FIG. 5 is an explanatory view showing a state in which a particulate matter purifying apparatus equipped with a felt filter with a density adjusting function according to a second embodiment is attached to a diesel engine.

[Explanation of symbols]

 2 Fiber 3 Fiber 9 Pressure gauge (flow resistance measuring means) 10 Rotation sensor (fluid flow monitoring means) 12 Fuel flow meter (fluid flow monitoring means) 14 Solenoid valve (fiber filling density adjusting means) 18 Electrode (flow resistance measuring means) A, B Felt filter

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F01N 3/02 F01N 3/02 301F 321 321D 321K F-term (Reference) 3G090 AA01 BA01 CB25 DA03 DA09 DA18 4D019 AA01 BA13 BB03 BB10 BC20 CB04 4D058 JA01 JB14 JB25 JB39 NA01 NA04 NA07 NA10 SA08

Claims (4)

[Claims] 1. A felt-like filter in which fibers are randomly laminated without being fixed to each other, a measuring means for measuring a flow resistance of a fluid passing through the filter, a fluid flow rate monitoring means passing through the filter, and the felt-like filter. Density adjustment means for adjusting the fiber packing density of the felt-like filter by operating the packing density adjustment means according to the detection signal output by the measuring means and the monitoring means. Felt filter with function. 2. The method according to claim 1, wherein the adjusting means is provided in front of the filter.
2. A felt filter with a density adjusting function according to claim 1, wherein the felt filter is provided with a valve and a valve driving means installed at the rear or front and rear. 3. A felt filter with a density adjusting function according to claim 1, wherein said adjusting means comprises an electrode provided around said filter and an electrostatic pressure adjusting means applied to said electrode. 4. The felt filter with a density adjusting function according to claim 1, wherein the filter is used as an exhaust gas purifying device for a diesel engine.