IWATA, Kyoichi (Ltd. Sinto Blastec Company 180-1Komaki, Ogi-cho, Toyokawa-sh, Aichi 05, 4411205, JP)
| Claims^
1.
An apparatus to feed precoat materials that feeds the precoat materials to a dust collector, comprising: a hopper for storing the precoat materials! a cover for an opening which can be opened and closed, placed at the opening formed so as to replenish the precoat materials in the hopper! a connecting duct for feeding the precoat materials to the dust collector," a flexible nozzle for blowing high-pressure air into the hopper! an electromagnetic valve which opens and closes a feed of the air from the source of the high-pressure air, and which is connected to a pipe that is connected to the nozzle! and a second air intake for taking the atmospheric air into the hopper, wherein when no high-pressure air is blown in from the nozzle the opening space of the second air intake is arranged so as to have the air flowing in the connecting duct be sucked in from the second air intake, and to have the speed of the air flowing in the connecting duct be from 2~5 m/s, and wherein the number of nozzles is arranged so as to be an integer to satisfy Vx50 + (θ~2), where V (m 3 ) is the volume of the hopper that stores the precoat materials.
2.
The apparatus to feed the precoat materials of claim 1, wherein the apparatus further comprises^ a timer for blowing air that sets the period for blowing high-pressure air from the nozzle, which the timer is electrically connected to the electromagnetic valve! a waiting timer setting the time to start blowing of air, which is electrically connected to the electromagnetic valve! and an accumulation timer for totaling the time when the air is blown.
3.
The apparatus to feed the precoat materials of claim 2, wherein the apparatus further comprises a resetting means to reset the accumulation timer.
4.
The apparatus to feed the precoat materials of any one of claims 1-3, wherein a level meter for detecting levels that detects the lower limit of the level of the precoat materials stored in the hopper is installed.
5.
The apparatus to feed the precoat materials of claim 4, wherein an emergency warning means that is electrically connected to the accumulation timer and to the level meter and signals a warning.
6.
A method to feed the precoat materials using an apparatus to feed the precoat materials to the dust collector, of claim 1, comprising: a process for arranging the opening space of the second intake so as to have the air flowing in the connecting duct be at a rate of 2~5m/s, based on the relationship between the speed of the air flowing in the connecting duct when no high-pressure air is blown from the nozzle, and the quantity of feed of the precoat materials! and a process for setting the number of nozzles under the condition that the opening space of the second air intake has been set as above, such that the number is an integer that satisfies Vx50 + (0~2), where V (m 3 ) is the volume of the hopper that stores the precoat materials.
7. A method to feed the precoat materials of claim 6, further comprising: a process wherein the two following steps are alternated, comprising: a step for blowing high-pressure air from the nozzle for a predetermined period! and a step for stopping blowing the high-pressure air for a predetermined period until the start of the next blowing! and a process for calculating the total time that the air is blown.
8.
A method to feed the precoat materials of claim 7, further comprising: a process for resetting the time totaling for blowing air when the precoat materials are replenished in the hopper.
9.
A method to feed the precoat materials of claim 7, further comprising: a process for resetting the time totaling for blowing air when the lower limit of the level of the precoat materials is detected.
10.
A method to feed the precoat materials of claim 8 or 9, comprising: a process warning when the total time of blowing air exceeds the predetermined period, or the lower level of the precoat materials has been detected. |
Description
An apparatus to feed precoat materials and a method therefor
Field of the invention [0001]
This invention relates to an apparatus to feed precoat materials and a method therefor. More specifically, it relates to an apparatus to feed precoat materials, which apparatus feeds a fixed quantity of precoat materials to a dust collector under stable conditions.
Background of the invention
[0002]
During the operation of a dust collector, to prevent it from leaking dust or to decrease the chances of dust catching fire, by forming a layer of precoat materials on a filter, which layer is formed by having the precoat materials in powder form, such as calcium dioxide or lime hydrate (calcium hydroxide), adsorbed on the filter of the dust collector together with the dust collected and attached to the filter, and mixed with the dust, has been conventionally adopted.
For example, an apparatus to deposit precoat materials on a filter is, as disclosed in Patent Reference 1, constituted so that the precoat materials are shot high in the air within the storage tank by high-pressure air blown through a nozzle, sucked into the dust collector by a dust-collecting stream, and deposited on the filter. Also, a certain screw feeder is used to feed a fixed quantity of various powders or granular particles, wherein the screw rotation speed or its operating time can be adjusted, based on the quantity of the powder materials which must be fed.
[0003]
Patent Reference I^ Japanese Examined Utility Model Application Publication
No. 41768/1991
Disclosure of the invention Problems to be solved [0004]
However, when the quantity of the feed of the precoat materials is to be increased in the apparatus of Patent Reference 1, if the area of the opening through which the dust collector communicates with the outside atmosphere is increased, the quantity of air that is sucked into the dust collector through the opening is increased. Then the precoat materials are unnecessarily sucked by the stream of air which is sucked through the opening. This will leave a difficult problem of controlling the quantity of the feed of the precoat materials that should be fed relative to the volume of the stream of air required for the collection of dust, which volume is variable. Moreover, many of the precoat materials are hygroscopic, and might solidify depending on the ambient humidity, such that the precoat materials are not effectively shot up in the air by high-pressure air blown thorough the nozzle. Therefore there still remains a problem in that the precoat materials are not suitably attached to the filter.
Also, if a screw feeder is used to feed a fixed quantity of powder, the total length, including the length of the screw, and its driving section, becomes longer than that of a hopper which stores the precoat materials. Therefore a problem arises in that the total area for the installation of the precoat feeding apparatus becomes larger. [0005]
The present invention intends to solve these problems. The present invention provides an apparatus to feed precoat materials and a method therefor, wherein a fixed quantity of the precoat materials is supplied to a dust collector,
and the precoat materials are supplied in stable conditions based on the relationship between the properties of the precoat materials, if for example, they are solidified, or in granular particles, and the total time for the blowing of air, such that the apparatus can be made compact. [0006]
The apparatus to feed precoat materials, of the present invention, feeds them to a dust collector. It comprises: a hopper for storing the precoat materials! a cover for an opening which can be opened and closed, placed at the opening formed so as to replenish the precoat materials in the hopper; a connecting duct for feeding the precoat materials to the dust collector; a flexible nozzle for blowing high-pressure air into the hopper; an electromagnetic valve which opens and closes a feed of the air from the source of the high-pressure air, and which is connected to a pipe that is connected to the nozzle; and a second air intake for taking the atmospheric air into the hopper, wherein when no high-pressure air is blown in from the nozzle the opening space of the second air intake is arranged so as to have the air flowing in the connecting duct be sucked in from the second air intake, and to have the speed of the air flowing in the connecting duct be from 2~5 m/s, and wherein the number of nozzles is arranged so as to be an integer to satisfy Vx50 + (0~2), where V (m 3 ) is the volume of the hopper that stores the precoat materials.
Further, the apparatus to feed the precoat materials preferably comprises: a timer for blowing air that sets the period for blowing high-pressure air from the nozzle, which the timer is electrically connected to the electromagnetic valve; a waiting timer setting the time to start blowing of air, which is electrically connected to the electromagnetic valve; and an accumulation timer for totaling the time when the air is blown.
[0007]
The method to feed the precoat materials, of the present invention, is one to feed them to the dust collector using an apparatus to feed the precoat materials. It is characterized in that it comprises: a process for arranging the opening space of the second intake so as to have the air flowing in the connecting duct be at a rate of 2~5m/s, based on the relationship between the speed of the air flowing in the connecting duct when no high-pressure air is blown from the nozzle, and the quantity of feed of the precoat materials; and a process for setting the number of nozzles under the condition that the opening space of the second air intake has been set as above, such that the number is an integer that satisfies Vx50 + (0~2), where V (m 3 ) is the volume of the hopper that stores the precoat materials.
The method to feed the precoat materials preferably comprises: a process wherein the two following steps are alternated, comprising: a step for blowing high-pressure air from the nozzle for a predetermined period! and a step for stopping blowing the high-pressure air for a predetermined period until the start of the next blowing! and a process for calculating the total time that the air is blown.
[0008] According to the present invention, a fixed quantity of the precoat materials can be supplied by suitably adjusting the area of the opening for the second air intake and adjusting the number of nozzles.
[0009] Also, according to the present invention, the precoat materials can be fed to the
dust collector under stable conditions, because the conditions of the precoat materials can be evaluated by the calculation of the total time that air is blown, starting from the time when the precoat materials are replenished in the hopper.
The best mode of the embodiment of the invention.
[0010]
An apparatus to feed precoat materials and a method therefor are now explained by referring to the attached drawings. This apparatus can be used as an apparatus to feed the precoat materials that are to be deposited on a filter of a dust collector, and mixed with the collected dust. The apparatus to feed precoat materials according to one embodiment of the present invention comprises, as shown in Fig. 1, in a hopper 2 that stores the precoat materials 1, a connecting duct 3 which leads the precoat materials in the hopper 2 to the dust collector (not shown), and a cover for an opening 4 which can be opened and closed, placed at an opening 2a formed so as to replenish the precoat materials 1 in the hopper 2.
Also, in the hopper 2, an opening for a second air intake 5 that intakes the air is disposed. The air is sucked through the hopper 2 to the connecting duct 3 of the dust collector at all times while the dust collector is operated. The opening space of the second air intake 5 is arranged, as will be described below, based on the conditions under which the precoat materials 1 are fed in a fixed quantity.
Further, a nozzle 6, made of a flexible polyurethane material, is disposed at the end of a pipe P that supplies air from the source of supply of the high-pressure air, so as to blow the air into the hopper 2. There can be one or more of the nozzle 6, under the conditions that the precoat materials are to be fed in a fixed quantity, such as is applied when the area of the opening for the second air
intake 5 is arranged. In the present embodiment, the nozzle 6 has two branches. The nozzle 6 has branches in the present embodiment. However, two nozzles that can be inserted into the end of the pipe P can be used, in place of a branched nozzle. An electromagnetic valve 7, which opens and closes the supply of the air from the source of the high-pressure air, is connected to the pipe P. By opening and closing this electromagnetic valve 7 the high-pressure air is intermittently blown in from the nozzle 6. When the air is blown in, the precoat materials 1 stored in the hopper 2 are shot up in the air at a high speed, and sucked by the sucking force of a dust- collecting blower (fan) into the dust collector.
[0011]
The apparatus to feed precoat materials, according to the present invention, monitors the total time that the air is blown from the time when the precoat materials are replenished in the hopper (total time of air blowing). Therefore it can evaluate the properties of solidification, granulation, and the like, of the precoat materials, and can feed the precoat materials to the dust collector under stable conditions. Namely, the precoat materials gradually solidify by absorbing the moisture in the air. Therefore, the properties of the precoat materials and the total time for the blowing of air are related. Therefore, the apparatus to feed precoat materials, according to the present invention, is constituted so as to warn when it detects the precoat materials being in the state of the abnormal properties (for example, the precoat materials are not shot up if they have solidified by absorbing the moisture), when the total time for blowing the air exceeds the predetermined period (the total time).
In this embodiment of the present invention, as shown in Fig. 1, a timer for blowing the air 8 that sets a time for blowing the air and a waiting timer 9 to count the time until the blowing of the air starts, which sets the time for starting to blow air are electrically connected to the electromagnetic valve.
Thus the timing of opening and closing the electromagnetic valve 7 can be predetermined, and intermittent blowing is realized (process of intermittent blowing).
A level meter 10 for detecting levels, as a detector, detects that the levels of precoat materials 1 stored in the hopper 2 have decreased, is installed on the hopper 2. When the quantity of the precoat materials in the hopper has decreased it signals a warning by means of an emergency warning 11, by, for example, displaying it on a panel or sounding a siren or a buzzer (process of emergency warning).
Further, an accumulation timer 12 for totaling the time for blowing air is installed. The accumulation timer 12 totals the time for blowing air from the time the precoat materials 1 are replenished in the hopper 2 (process of totaling the time for blowing air). If the total time for blowing the air exceeds the predetermined period, it determines that the stored precoat materials have not decreased normally. Namely, if the precoat materials have not been replenished (supplied) or the lower level of the precoat materials 1 has not been detected by the meter determining the levels, even if the high-pressure air has been blown through the nozzle(s) for the predetermined period for blowing air, it is estimated that the precoat materials have not been sucked into the dust collector, and that an emergency situation has occurred, as, for example, the precoat materials had solidified, the precoat materials had leaked from the hopper, or the like.
Thus based on this estimate, the emergency warning means 11 gives a warning. Further, installed is a resetting means 13. It resets the accumulation timer 12 when an operator replenishes the precoat materials in the hopper 2.
Resetting the accumulation timer 12 is also done by the output from the level
meter 10, when the level meter detects the lower limit of the level of the precoat materials when the precoat materials become scarce (process of resetting the timer for totaling the time for blowing air).
[0012]
In the present embodiment, the material of the nozzle is polyurethane. But if the material is elastic and a nozzle using that material moves violently when the high-pressure air is blown from the nozzle, nylon, silicon, etc., can be used. But other such materials can be used.
Also, a level meter, such as a rotational-type, capacitance-type, etc., in so far as if can detect the lower limit of the level of the powder material, can also be used.
[0013]
This invention was made in view of the finding that the opening space of the second air intake and the number of nozzles must be suitably arranged so that the precoat materials can be fed in a fixed quantity to the dust collector. The arrangement is explained below based on the Examples.
Examples^
[0014]
The present invention will now be explained based on an example thereof while it should be noted that the present invention is not limited to only this example.
First, the relationship between the speed of the air which flows in the connecting duct and the quantity of the precoat materials that are replenished was investigated by changing the opening space of the second air intake. For the experiment, the speed of the air which flows in the connecting duct was measured by the air speedometer attached to the connecting duct. It was
attached at the opening arranged for this experiment. It was 200 mm above the upper surface of the hopper.
Table 1 shows the stability of the quantity of the feed of the precoat materials relative to the speed of the air. In Table 1 the mark "O" shows that the supply is stable, the mark "δ" shows that the supply is relatively stable, but insufficient, and " x " shows that the supply is not at all stable.
[0015] Table 1
Fig. 2 shows the results of the supply of the precoat materials in one example when the speed of the air was at 3.8 m/s. Fig. 3 shows the results of the quantity of the feed of the precoat materials for another example, when the speed of the air was at 6.8 m/s. The dotted line in both Figs. 2 and 3 is a regression line. It is seen from Fig. 2 that the supply was stable when the speed of the air was at 3.8 m/s, but from Fig. 3 that it was not stable when the speed of the air was at 6.8 m/s. Table 1 shows that the speed of the air that flows in the connecting duct was most preferably 2-5 m/s, because when the speed of the air was less than 2 m/s, a sufficient feed could not be obtained. When the speed of the air was more than 5 m/s, a stable feed could not be obtained. Therefore it
was found that preferably the opening space of the second air intake was arranged so as to have the air flowing in the connecting duct be at 2-5 m/s when the high-pressure air was not blown from the nozzle. [0016] Next, the number of nozzles is to be determined when the opening space of the second air intake is arranged so that the speed of the air will be 2-5 m. The experiment was made wherein the volume of the hopper was 0.064 m 3 , the speed of the air was 3.8 m/s, and there were 3 or 4 nozzles. Table 4 shows the results of the experiment with 3 nozzles. Table 2 shows the results of the experiment with 4 nozzles.. The dotted line in Fig. 4 is a regression line. Both Figs. 2 and 4 show a stable feed, but as shown in Fig. 2, a larger feed was realized with more nozzles. A further survey regarding the number of nozzles showed that an appropriate number was 4-5 when the volume of the hopper was 0.064 m 3 , and that it was 1-2 when the volume of the hopper was 0.018 m 3 . The range is expressed as V x 50 + (0~2), wherein V is the volume of the hopper that stores the precoat materials. Therefore preferably the number of nozzles in relation to the volume of the space that stores the precoat materials should be an integer that satisfies the following formula'- V x 50 + (0-2) (1)
This formula shows the range between the upper limit for the number of nozzles and the lower limit for it, indicating that the number of nozzles more than the upper limit or less than the lower limit is outside this range. For example, when the volume of the hopper is 0.064 m 3 , the formula is shown as 3.2 + (0~2) = 3.2~5.2, making the integer included within this range, i.e., 4~5, as the number of nozzles.
[0017]
Next, Fig. 2 shows, as discussed above, a change over time of the quantity of the precoat materials fed to the dust collector by the apparatus to feed the precoat
materials, of the present invention. Fig. 2 shows the result obtained from the example wherein the pressure of the blown air is 0.3 MPa, the period for the blown air is 10 seconds, the time until the air starts to be blown is 10 seconds, and the static pressure is 200 H2O at the duct above the hopper. The opening space of the second air intake was 200 mm 2 ' The speed of the air that flowed in the connecting duct was 3.8 m/s when the high-pressure air was not blown in from the nozzles. The volume of the hopper that stored the precoat materials was 0.064 m 3 and the number of branched nozzles was 4, as calculated from formula (l).
[0018]
As is clear from the explanation, in one embodiment according to the present invention, by appropriately arranging the opening space of the second air intake and the number of nozzles it is possible to feed a fixed quantity of the precoat materials to the dust collector. Also, by monitoring the total time for blowing air starting from the time the precoat materials are replenished in the hopper, it becomes possible to evaluate the properties of the precoat materials, such that the precoat materials can be fed into the dust collector under stable conditions. Further, the precoat materials within the hopper can be fed directly to the dust collector through the connecting duct, such that the structure of the apparatus can be made compact.
Brief descriptions of the drawings
Fig. 1 shows a schematic diagram according to the apparatus to feed the precoat materials in one embodiment of the present invention.
Fig. 2 shows a change of the quantity of the feed of the precoat materials over time when the apparatus to feed the precoat materials, according to the present invention, is used.
Fig. 3 shows a change of the quantity of the feed of the precoat materials over time both when the opening space of the second air intake is large and when the quantity of the air flowing in the connecting duct is great.
Fig. 4 shows a change of the quantity of the feed of the precoat materials over time when there are fewer nozzles.
Explanation of symbols
1. pre-coat materials
2. hopper
2a. opening for replenishing the precoat materials
3. connecting duct 4. cover for the opening for replenishing the precoat materials
5. opening for the secondary air intake
6. nozzle
7. electromagnetic valve
8. timer for blowing the air 9. waiting timer to count the time until the blowing of the air starts
10. level meter for detecting levels
11. emergency warning means
12. accumulation timer for totaling the time for blowing air
13. resetting means to reset the timer for totaling the time for blowing air P pipe