JPH02160013A - Ceramic filter for removing and recovering soot - Google Patents

Abstract

PURPOSE:To enhance the oil collection rate and recovery rate of the subject filter by providing a skeletal structure obtained by looping a ceramic wire and controlling the water absorption to a specified value. CONSTITUTION:The soot in a gas is removed and oil is recovered by the ceramic filter. In the filter, a ceramic wire 10 is looped on a plane, and the centers of the loops are alternately shifted to form a loop array 11. The loop arrays 11 are arranged along said plane and in the direction orthogonal to the plane to form the skeleton. The water absorption of the skeleton is con trolled to <=5% per unit volume of the skeleton. As a result, the oil collection rate and recovery rate are enhanced, and a flame is hardly passed through the structure.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is installed in a duct of a large kitchen, etc., and removes oil smoke generated from cooking from gas discharged through the duct 1-, and recovers oil content. This invention relates to a ceramic filter for removing and collecting oil smoke.

[Prior art] Generally speaking, the lower floors of large urban buildings are occupied by many eateries such as restaurants and coffee shops, and some of the oil smoke generated from the kitchens of these restaurants is removed and collected. filter. Gas containing oil smoke that cannot be completely removed by the filter is then discharged to the outdoors through ducts that run throughout the building.

Therefore, if the removal efficiency of the filter is insufficient, the inside of the duct will become contaminated with oil after long-term use, and if a fire occurs, the flame will propagate through the duct and cause a large fire. There is a risk of this happening. For this reason, it is necessary that the filter has high oil removal efficiency.

Furthermore, during the cooking process, it is common for flames to temporarily rise from a frying pan or the like. In this case, if a large amount of oil adheres to the filter and the oil is likely to catch fire, there is a risk that the flame will propagate to the filter itself and cause a fire as well. Therefore, in order to prevent such a fire from occurring, the filter must first be resistant to the accumulation of oil, which is a combustible substance.

Furthermore, it is also necessary that the filter has a structure such that the generated flame is reliably blocked by the filter surface and does not enter the duct.

Based on the above, the following conditions must be met for a kitchen filter: 1. To collect oil smoke generated from the kitchen with high efficiency, and 2. to drain the collected oil as quickly and efficiently as possible without depositing it on the filter surface. 4. Even if a flame occurs in the kitchen, the filter has a function to prevent the flame from passing through the filter and propagating to the duct. Conceivable.

Further, generally, the above-mentioned collection efficiency is required to be 60% or more, and the recovery efficiency is required to be 80% or more.

Fig. 5 is a schematic plan view showing a conventional oil smoke collection filter;
FIG. 6 is a schematic perspective view showing the lower part of the same. The baffle plate 1.2 has a cross section bent in the shape of a mouthpiece,
It is a rod-shaped member that extends long in the vertical direction, and is made of rust-resistant material such as stainless steel. A plurality of baffle plates 1 are arranged as primary side baffle plates on the kitchen side, and are arranged with gas introduction intervals between them.

On the other hand, the plurality of baffle plates 2 are disposed on the duct side as secondary side baffle plates, and are arranged with gas discharge intervals between them. The baffle plate 1 and the baffle plate 2 have inner surfaces facing each other, and a pair of adjacent baffle plates 1 and 2 have inner surfaces facing each other.
(or 2) are combined so that one baffle play 1 to 2 (or 1) engages. A toy-shaped oil collection member 3 is arranged at the lower end of the baffle plate 1.2, and this oil collection member 3 includes the baffle plate 1,
The oil flowing along the surface of the oil collecting member 2 is collected, and the oil is discharged through an oil outlet 4 provided in the oil collecting member 3 and collected in a suitable tank.

The conventional baffle-type oil smoke removal and recovery filter configured in this manner is installed at the entrance of a kitchen duct with the baffle plate facing downward in the longitudinal direction and in a downward position from above. The gas in the kitchen sucked by the suction blower installed in the duct first enters the filter through the gas inlet between the primary side baffle plates 1, as shown by the arrow, and then enters the filter on the secondary side. It collides with baffle brakes 1 and 2 and changes its course, and then the secondary baffle plate 2
The gas is exhausted from the filter through the gas outlet between.

During this time, the oil in the gas is removed from the baffle plate 1.
2 and collected in the oil collection member 3. The above-mentioned collection rate and recovery rate of this conventional filter are approximately 60% and 80%, respectively.
% or more, recovery rate of 80% or more).

[Problems to be Solved by the Invention] However, the collection rate of about 60% means that about 40% of the generated oil smoke is always carried into the duct. The oil smoke that has entered the duct adheres to the inner surface of the duct, contaminates the inner surface of the duct, and eventually
Oil accumulates on the inner surface of the duct in a relatively short period of time. It is necessary to periodically clean the inside of this duct, but cleaning the inside of this duct is extremely difficult and complicated work. Therefore, there is a strong demand for improvement in the collection efficiency of oil smoke removal and recovery filters.

Furthermore, the structure in which the baffle plates 1 and 2 are combined has the drawback that the spacing between the plates cannot be made very narrow, and that it is relatively easy for flame to pass through to prevent pressure loss.

The present invention has been made in view of these problems, and it is an object of the present invention to provide a ceramic filter for removing and recovering oil smoke that has both a high oil collection rate and a high recovery rate, and has a structure that makes it difficult for flames to pass through. purpose.

[Means for Solving the Problems] A ceramic filter for removing and recovering oil smoke according to the present invention is a ceramic filter for removing and recovering oil smoke that removes oil smoke from gas and recovers oil components, in which a ceramic linear body is placed on a flat surface. It has a skeleton formed by forming it into a loop shape and shifting the centers of the loops to form a loop row, and arranging the loop rows in a direction along the plane and in a direction perpendicular thereto, and the water absorption of this skeleton is 5% per unit volume of skeleton
It is characterized by the following regulations.

[Function] In the present invention, the skeleton formed from ceramic aggregate has loop rows arranged approximately regularly in the direction along the molding plane and in the direction orthogonal thereto.

Because of this structure, a filter with this skeletal structure has the advantage that it is difficult for flame to pass through, and the gas flow path is complicated, so oil smoke particles easily collide with the skeletal structure, resulting in a high collection rate.

In addition, since the loop structure of the skeleton and the material of the ceramic linear bodies are regulated so that the water absorption rate of the skeleton is 5% or less per unit weight of the skeleton, the accumulation of oil adhering to the skeleton is small and the oil content is high. It separates from the skeleton at a recovery rate.

Therefore, it is possible to obtain a filter in which the collection rate is significantly improved, the recovery rate is also high, and it is difficult for flames to pass through.

The water absorption rate is 11 L (cc) of water contained per unit ffl (CC) of the filter skeleton composed of the loop rows 11 shown in FIG. After measuring the body fat (that is, the volume including pores) and weight (filter weight before water absorption), the filter material is immersed in water. After a predetermined period of time has elapsed, the filter material is taken out of the water and compressed air is blown onto the filter material to remove adhering water and standing water from the surface of the filter material. Thereafter, the weight of the filter material is measured to determine the weight of the filter after water absorption. The water absorption rate is calculated by the following formula (1) based on these measurement results.

Water absorption amount (cc) Weight of water (g) = (Weight of filter after water absorption, g) - (Weight of filter before water absorption, g) x 100
・ (1) In reality, it is oil, not water, that adheres to the filter, but if vegetable oil for tempura and water are made to absorb oil and water, respectively, into the ceramic material itself, the amount of oil absorbed and There is no substantial difference between the amount of water absorption, and there is a certain correlation between the amount of oil absorption and the amount of water absorption. For this reason, the characteristics are evaluated and limited by the water absorption rate using water, taking into consideration the ease of testing.

[Example] Next, an example of the present invention will be specifically described with reference to the accompanying drawings.

FIG. 1 shows the skeletal structure of a ceramic filter for removing and recovering oil smoke according to an embodiment of the present invention. This skeletal structure is manufactured as follows. First, the kneaded ceramic material is linearly extruded from the nozzle of an extruder, and this linear body 10 is
is placed on a flat surface while rotating the nozzle, and the nozzle is moved linearly in the direction shown by the arrow in FIG. As a result, a loop row 11 is obtained in which a plurality of loops whose loop centers are mutually shifted in the direction of the arrow are chained together. In this way, after a plurality of loop rows 11 are arranged along the - plane with their row directions parallel to each other, another plurality of loop rows 11 are similarly stacked thereon. In this case, the upper loop row is arranged on the lower layer loop row so that the center of each loop is shifted by the radius of the loop in a direction perpendicular to the row direction. In this way, the loop arrays 11 are arranged in a direction along the arrangement plane and in a direction perpendicular thereto (the stacking direction) to form a predetermined skeleton shape. Thereafter, this ceramic structure is cut into a predetermined shape, dried, and then fired to obtain a filter.

This filter has a thickness determined by the number of stacked loop arrays 11, and is formed into an appropriate shape, such as a rectangle or a rectangle.

A filter with a loop-shaped skeleton structure has a high rate of capturing oil in gas. In other words, when gas tries to pass in a direction perpendicular to the plane of the paper in Figure 1, the gas passes through the filter through a complicated flow path. Moreover, the surface area of the skeleton is extremely large because the skeleton is made up of linear aggregates with a small diameter. Therefore, oil adheres to the skeleton and is removed from the gas with high efficiency.

FIG. 2 is a graph showing the collection characteristics of the filter, with the operating time as a filter plotted on the horizontal axis and the collection rate plotted on the vertical axis. This collection rate was determined using the oil smoke generator shown in FIG. That is, in this oil smoke generator, the filter 20 whose ventilation part is a square of 500 dragons on a side is placed at the top, and the filter 20 at the bottom.

The oil pan 21 is made of stainless steel. Water is then pumped out at a rate of 3 per second from the water tank 23 that stores water and the oil tank 24 that stores vegetable oil for tempura.
Drops and oil are dropped into the oil pan 21 at a rate of one drop per second. Note that water is added dropwise to promote evaporation of oil.

The oil pan 21 is equipped with an electric heater 22 (220W, 2KW
), and this electric heater 22
It is heated to 50°C. Further, the back surface of the filter 20 is designed to be suctioned at a wind speed of 1.1 m/sec by an exhaust blower (not shown).

Using such a test device and test conditions, the collection rate of oil collected by the filter 20 was calculated from the following equation (2).

(Catching rate, %) The collection rate calculated in this way is shown in FIG.

In the figure, the solid line indicates the filter according to the embodiment of the present invention (water absorption rate 2
．． 5%), and the - dotted chain line indicates a filter whose skeleton structure is the same loop shape as in Fig. 1, but whose water absorption rate is 7.5%, which is outside the scope of the claims of the present invention. .

Furthermore, the broken line indicates a conventional stainless steel baffle type filter.

As shown in Figure 2, the collection rate of the filter with the loop-shaped skeleton shown in Figure 1 is extremely high at approximately 90%, compared to approximately 60% for the conventional baffle type filter. have a rate. Further, in this loop-shaped filter, there is very little difference in collection rate due to a difference in water absorption rate.

Next, the oil recovery rate will be explained. FIG. 4 is a graph showing the recovery characteristics of the filter, with the operating time as a filter plotted on the horizontal axis and the recovery rate plotted on the vertical axis. In addition, like the collection rate, the recovery rate is determined by the amount of oil attached and the amount recovered using the apparatus shown in Figure 3.

was measured and calculated based on the following formula (3).

Recovery rate (%) (Collection container recovery amount, g) + (filter adhesion amount, g)X1
00...(3) As in Figure 2, the obtained recovery rates are calculated for loop filters and stainless steel baffle filters with water absorption rates of 2.5% and 7.5%. A comparison is shown in Figure 4.

As is clear from Fig. 4, the recovery rate of the conventional stainless steel baffle type filter is as high as about 80%, and the loop-shaped frame filter of this example, which has a water absorption rate of 2.5%, also has a water absorption rate of 2.5%. After that, like the baffle type filter, about 80
% recovery rate.

On the other hand, a loop-shaped ceramic filter with a water absorption rate of 7.5% has a low recovery rate of 60% even after 12 hours. By using ceramic as the filter material, the desired fire resistance can be obtained, but normally, The ceramic material itself contains fine pores, and attached oil is easily taken into these pores.Furthermore, the structure of the loop-shaped filter itself has a large contact area with oil, which increases the collection rate. On the other hand, the attached oil is difficult to separate from the surface of the aggregate and tends to remain.

As described above, in the loop-shaped ceramic filter, attached oil tends to remain, and the recovery rate is lower than that of a baffle-type filter, which is basically a flat filter.

However, even with a ceramic filter with a loop-shaped skeleton, when the water absorption rate is 2.5%, the recovery rate is higher than when the water absorption rate is 7.5%, and moreover, it can be recovered relatively quickly after operation. The recovery rate increases to approximately the same level as the recovery rate of the filter. Therefore, in the present invention, in order to obtain the recovery rate necessary for a filter for removing oil smoke, the water absorption rate of the loop-shaped ceramic skeleton is regulated to 5% or less. In this way, a loop-shaped ceramic filter with a water absorption rate of 5% or less has a collection rate that is significantly higher than that of a conventional baffle-type filter.

It has a sufficiently high recovery rate similar to that of Note that the water absorption rate of 5% or less includes cases where the water absorption rate is substantially 0%.

In order to regulate the water absorption rate to 5% or less, the composition of the ceramic aggregate is 5i02; 40 to 60% by weight, AfI20
3: 20 to 40% by weight, MgO: 5 to 15% by weight,
It is preferable to have K2O: 0.5 to 4.0% by weight, Na2O: 0.2 to 1.0% by weight, and the balance being unavoidable impurities.A ceramic material with this composition has few pores and absorbs little oil.

Next, the relationship between the composition of the ceramic aggregate, the water absorption rate per unit volume of the skeleton, and the regeneration workability will be explained. Ceramic materials A and B shown in Table 1 below.

Each of the filters C has a composition shown in the filter main component column of Table 1, and has a loop-shaped skeleton as shown in FIG. For each filter, the water absorption rate per unit volume of the skeleton and the regeneration workability after use as a filter are also shown in Table 1. Ceramic material A has a K2O component outside the above-mentioned composition range; The water absorption rate is also high at 7.5%.

Note that the wire diameter of the ceramic aggregate is 1.5 m+s, and the porosity of the entire filter is 70%, which is uniform for each filter.

Moreover, the regeneration workability after use was evaluated by a method in which the used filter was immersed in a detergent solution commonly used in households, and then washed with water.

Table 1 As a result, those with a water absorption rate of more than 5% per skeletal unit volume (ceramic material A) are filter aggregates.

The oils and fats taken into the micropores inside tend to remain unwashed, and cannot be easily washed.For this reason, the regeneration workability is poor. On the other hand, ceramics B and C having a water absorption rate of 5% or less and conventional baffle type filters are easy to clean and have a regeneration workability of O.

The above test results are for filters in which the aggregate consists of a single ceramic linear body of each composition, but for example,
The fired filter aggregate of Ceramic A is coated with Ceramic C, a glassy substance with a low water absorption rate, and fired again to reduce the water absorption rate of only the surface of the aggregate, thereby reducing the water absorption rate of the entire skeleton to 5% or less. Similar good effects can be obtained even if it is regulated to . In addition, a glaze was used instead of ceramic C as a coating material, and this glaze reduced the water absorption rate of the aggregate surface and regulated the water absorption rate of the entire skeleton to 5% or less, but the same good effect was obtained. It will be done.

As described above, by changing the composition of the filter aggregate having a loop-shaped skeleton structure to one with a low water absorption rate, or by coating the surface of the aggregate with a vitreous ceramic having a low water absorption rate, the material of the aggregate can be improved. Based on practical considerations, the water absorption rate in the entire skeleton can be regulated to 5% or less. In addition, by examining the loop-like skeleton structure (loop diameter, pitch, etc.),
Water absorption rate can be reduced. Thereby, the collection rate can be significantly increased compared to the conventional method while ensuring a sufficient recovery rate. Therefore, contamination of the duct can be extremely effectively prevented.

In addition, the loop-shaped skeleton structure described above is resistant to thermal shock, so in order to regenerate a filter that has been used for a long time and has become contaminated with oil, it can be used to clean the filter by immersing it in water and then drying it by heating. Even if the filter is subjected to sudden temperature changes, it is prevented from being destroyed by thermal shock.

Furthermore, since the steel baffle plate of conventional filters has good thermal conductivity, the surrounding area is easily affected by heat during use as a filter, but when the aggregate is made of ceramic as in this example, Since the filter has a low thermal conductivity, surrounding members are relatively less likely to receive heat, and the area around the filter can be easily designed.

[Effects of the Invention] According to the present invention, the skeleton structure is formed by forming a ceramic linear body into a loop shape, and the water absorption rate is 5% per unit volume of the skeleton.
With the following regulations, it is possible to significantly increase the oil collection rate while ensuring a sufficiently high recovery rate. Further, the above-mentioned skeletal structure is difficult for flame to pass through, and is resistant to thermal shock and has high durability.

Furthermore, the playability is also excellent.

[Brief explanation of the drawing]

FIG. 1 shows a filter skeleton tilI according to an embodiment of the present invention.
Fig. 2 is a graph showing the water absorption characteristics of each filter, Fig. 3 is a schematic diagram showing the oil smoke generator for oil smoke removal and recovery tests, and Fig. 4 shows the recovery characteristics of each filter. FIG. 5 is a schematic plan view showing a conventional baffle type oil smoke removal and recovery filter, and FIG. 6 is a schematic perspective view of the lower part thereof. 1.2; baffle plate, 10; ceramic linear body,
11; loop row, 20; filter, 21; oil pan,
22; Electric heat filter

Claims (3)

[Claims] (1) In a ceramic filter for oil smoke removal and recovery that removes oil smoke from gas and recovers oil components, loop rows are formed by forming a ceramic linear body into a loop shape on a flat surface and shifting the centers of the loops from each other. and has a skeleton configured by arranging the loop rows in a direction along the plane and in a direction perpendicular thereto, and is characterized in that the water absorption rate of this skeleton is regulated to 5% or less per unit volume of the skeleton. Ceramic filter for removing and collecting oil smoke. (2) The ceramic aggregate constituting the skeleton contains 40 to 60% by weight of SiO_2 and 20 to 40% by weight of Al_
2O_3, 5-15% by weight MgO, 0.5-4.
0 wt% K_2O and 0.2-1.0 wt% Na
The ceramic filter for oil smoke removal and recovery according to claim 1, characterized in that it has a composition containing _2O and the remainder consisting of inevitable impurities. (3) The ceramic filter for removing and recovering oil smoke according to claim 1 or 2, wherein the surface of the aggregate constituting the skeleton is coated with glass or other similar materials.