JP4730150B2 - Wood fumigation method - Google Patents

Description

  The present invention relates to a method for fumigating wood, and in particular, to a method for fumigating wood in which a fumigant containing methyl iodide as an active ingredient is used and the wood is fumigated by spraying it.

In the fumigation of wood, the use of methyl iodide instead of methyl bromide is spreading due to environmental considerations. Methyl iodide is also confirmed to have a pest control effect comparable to methyl bromide. ing. Fumigation with methyl iodide is also performed by a so-called awning method, as in the conventional method. For example, methyl iodide is contained in a lidded container equipped with a hot water jacket, and the container is placed inside a sheet (tent) covering wood. Is released to diffuse the vaporized methyl iodide inside the sheet.
JP 2003-136506 A

  In awning type wood fumigation, many pieces of wood are usually stacked inside the sheet, but when methyl iodide is used for fumigation, the specific gravity of methyl iodide is large, so vaporized methyl iodide is removed from the container. Immediately it flows down to the ground surface side and tends to stay near the ground. As a result, depending on the stacked position, the concentration of methyl iodide is low, and there is a possibility that wood with insufficient fumigation may be generated.

  The present invention has been made in view of the above circumstances, and an object thereof is a method of fumigating wood with a fumigant containing methyl iodide as an active ingredient, which is more efficient and the total number of target wood. It is an object of the present invention to provide a method for fumigating wood that can reliably be fumigated.

  In order to solve the above-mentioned problems, the present invention is a tent-type fumigation method in which stacked wood is covered with a sheet, and when using a fumigant containing methyl iodide as an active ingredient, the fumigant is sprayed on the top of the wood. As a result, the mist-like fumigant is dispersed in a wide range and promotes its vaporization, and further, the vaporization is further promoted by supplying air or the like immediately after spraying, and the vaporized fumigant is spread over a wide range. I made it diffuse.

That is, the gist of the present invention is a method of fumigating wood with a fumigant containing methyl iodide as an active ingredient, wherein a nozzle member of a spraying device is disposed on the top of the stacked wood , and the wood is used together with the nozzle member. The present invention resides in a wood fumigation method characterized by covering with a sheet and spraying a fumigant from the nozzle member and then supplying air or an inert gas from the nozzle member .

  According to the method of fumigation of wood according to the present invention, when using a fumigant containing methyl iodide as an active ingredient, the fumigant is sprayed on the top of the stacked wood, and thus a mist-like fumigant is widely dispersed. The vaporization can be promoted and air or an inert gas is supplied after spraying, so that the vaporization can be further promoted and the vaporized fumigant can be diffused in a wider range. As a result, the fumigant concentration in the processing space inside the sheet can be made uniform at a high concentration, so that fumigation can be performed efficiently.

  An embodiment of a wood fumigation method according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a concept of a wood fumigation method according to the present invention, and FIG. 2 is an assembly view showing a configuration example of a spraying apparatus applied to the present invention. Hereinafter, the method of fumigation of wood is abbreviated as “fumigation method”.

  The fumigation method of the present invention is a so-called tent-type fumigation method in which stacked wood is covered with a sheet. In such a fumigation method, wood is fumigated by spraying a fumigant containing methyl iodide as an active ingredient. In the present invention, methyl iodide is usually used alone as a fumigant. Methyl iodide is a liquid having a boiling point of 42.5 ° C. and can be vaporized relatively quickly by spraying in a mist form as described later. In the fumigant, a conventionally known wood fumigant such as methyl bromide, sulfuryl fluoride, methyl isocyanate, and propylene oxide may be used in combination within the allowable range.

  First, the spray apparatus for fumigant spray used in the present invention will be described. Such a spray device, as indicated by reference numeral (4) in FIG. 2, is filled with a fumigant and is capable of extruding the fumigant with an internal compressed gas, and extends from the fumigant container. A nozzle member (9) which is provided at the tip of the pipe (81) and sprays the fluid in a mist form, and a base on the fumigant container (5) side of the pipe (81) which is compressed and filled with air or an inert gas And a gas container (6) connected via a second pipe (82) to the spraying of the fumigant from the fumigant container (5) and air or inert gas from the gas container (6). It is configured to be able to switch between air feeding.

The fumigant container (5) is a pressure vessel pre-filled with a fumigant (liquid) to be described later and a compressed gas for extrusion, and the fumigant is pushed out through a siphon tube extended to the bottom of the container. . The dosage of the fumigant is usually 10 to 100 g / m ³ , preferably 30 per unit volume of the processing space in which the wood is accommodated (the space including the wood (1) inside the sheet (2) shown in FIG. 1). ˜80 g / m ³ . Considering the above dosage and the amount of wood processed per time, the filling amount of the fumigant in the fumigant container (5) is usually about 5 to 20 kg. Air or an inert gas can be used as the compressed gas for extrusion, but it is usually filled with air. The air filling pressure is 0.3 to 0.8 MPa.

  As shown in FIG. 2, a flexible pipe (81) is connected to the neck valve of the fumigant container (5) via a joint (7), and a nozzle member is attached to the tip of the pipe (81). (9) is provided. For example, the nozzle member (9) can be arranged in a state where it is placed on the top of the stacked wood (1) (see FIG. 1), for example, along a straight pipe whose tip is sealed and its longitudinal direction. It comprises a plurality of spray nozzles (91) attached at a constant pitch.

  As the spray nozzle (91), a nozzle having a structure capable of forming a mist having a smaller particle diameter and spraying a mist at a wider angle when a fumigant is ejected is preferable, and a spiral groove is formed on the surface. Various types of spray nozzles of a so-called wide angle spray type in which a block-shaped flow path member and a screw that are provided are incorporated at the tip of the nozzle can be used. The number of spray nozzles (91) is not particularly limited, but is usually about 2 to 5 in order to spray the fumigant more widely and evenly in plan view.

  The gas container (6) is a pressure-resistant container filled with compressed air or a compressed inert gas, and after extruding the fumigant from the fumigant container (5), it is placed inside the pipe (81) and the nozzle member (9). It is provided for further extruding the remaining fumigant and diffusing the vaporized fumigant in the treatment space (the space inside the sheet (2)). As the gas container (6), one having a filling amount of 9.4 to 26.8 liters (volume in a standard state) filled with air is usually used. The gas container (6) is connected to the joint (7) via a flexible second pipe (82) extended from the neck valve.

  A joint part (7) as a switching mechanism is attached to the neck valve of the fumigant container (5). The joint portion (7) is configured by attaching on-off valves (71) and (72) to one end of the straight pipe portion and the branch pipe portion of the cheese joint, respectively. Therefore, during the fumigation process, the fumigant is taken out from the fumigant container (5) and released from the nozzle member (9) by opening the on-off valve (71) together with the neck valve of the fumigant container (5). I can do it. The second pipe (82) extended from the gas container (6) is connected to the on-off valve (72) of the branch pipe section. Therefore, after spraying the fumigant, the open / close valve (72) is opened together with the neck valve of the gas container (6) to take out air from the gas container (6) and release it from the nozzle member (9). I can do it.

Next, the fumigation method of the present invention using the spray device (4) will be described. In the present invention, as shown in FIG. 1, first, the wood (1) to be subjected to batch processing is piled up. For example, in the case of wood (1) having a diameter of about 300 mm, about 100 pieces are piled up as a single process, although it depends on the size of the wood (1). In other words, the wood (1) is piled up so that the total apparent volume is about 100 m ³ . Next, the nozzle member (9) of the spraying device (4) is disposed on the top of the stacked wood (1). In that case, since the spray nozzle (91) of the nozzle member (9) sprays the fumigant to every corner, it is preferable that it is directed substantially downward.

  After arrange | positioning a nozzle member (9), the whole wood (1) piled up with the nozzle member (9) is covered with a sheet | seat (2). As the sheet (2), for example, a polyethylene fumigation sheet having a thickness of 0.2 mm is used. The outer periphery of the sheet (2) covering the wood (1) is pressed using a weight (3) such as a sand bag or a water bag so that no gap is generated between the floor or the ground. .

  After covering the wood (1) with the sheet (2) as described above, the fumigant is sprayed on the top of the stacked wood inside the sheet. Specifically, after covering with the sheet (2), the neck valves of the fumigant container (5) and the gas container (6) are first opened. Next, the opening / closing valve (71) of the joint part (7) is opened, and the fumigant in the fumigant container (5) is released. By such an operation, the fumigant can be sprayed in a mist form from each spray nozzle (91) of the nozzle member (9). Usually, the spraying time of the fumigant is about 5 to 10 minutes.

  When spraying of the fumigant is completed, air or an inert gas is sent to the inside of the sheet (2). That is, after spraying the fumigant, air or inert gas is discharged from the spray nozzle (91) of the nozzle member (9). Specifically, when spraying of the fumigant is completed, the neck valve and the on-off valve (71) of the fumigant container (5) are closed, and the on-off valve (72) is immediately opened. By such an operation, the air in the gas container (6) can be supplied to the pipe (81), and the air can be discharged from the nozzle member (9) to the inside of the sheet (2). Thereby, the fumigant remaining inside the pipe (81) and the nozzle member (9) can be discharged, and the air in the processing space inside the sheet (2) is agitated by the supplied air. I can do it. Usually, the air supply time is about 5 to 7 minutes.

  In the present invention, the timing for supplying air or inert gas is preferably immediately after spraying the fumigant. Immediately after spraying means within 2 to 3 minutes from the end of spraying the fumigant. The reason for sending air etc. immediately after spraying the fumigant is as follows.

  That is, when the fumigant is sprayed, the wood (1) to which a large amount of fumigant mist adheres and the wood (1) to which the fumigant mist adheres are generated depending on the piled state of the wood (1). On the other hand, the fumigant adhering to the surface of the wood (1) is in the form of mist and is vaporized within a relatively short time. However, depending on the size of the specific gravity, the fumigant flows downward as a gas, and the sheet (2) It stays in the lower part of the inner processing space. Therefore, before the sprayed fumigant is completely vaporized, in other words, the vaporization of the fumigant is further promoted by stirring the air in the process space while vaporizing, and the fumigant in the entire process space. The density can be made uniform and high. And the vaporization promoting effect and high concentration homogenizing effect of the fumigant as described above can be obtained by stirring the air in the treatment space within 3 to 15 minutes, preferably within 2 to 3 minutes from the end of spraying. Was confirmed from the experiment.

  The fumigation process as described above ends after 24 hours from the spraying of the fumigant. When the treatment is completed, the sheet (2) is peeled off, and the wood (1) is exposed to the atmosphere to release the fumigant remaining inside the sheet (2) and the fumigant adsorbed on the wood (1). To do.

  According to the fumigation method of the present invention, as described above, in the fumigation treatment of the awning method in which the stacked wood (1) is covered with the sheet (2), when using a fumigant containing methyl iodide as an active ingredient, Since the fumigant is sprayed on the upper part of the stacked wood (1), the mist-like fumigant can be widely dispersed and the vaporization thereof can be promoted, and air or an inert gas is supplied after the spraying. Therefore, vaporization can be further promoted and the vaporized fumigant can be diffused in a wider range. As a result, the fumigant concentration in the treatment space inside the sheet (2) can be made uniform at a high concentration, and all the wood (1) to be treated can be efficiently fumigated with a small amount of fumigant.

  And according to the fumigation method of this invention using the spraying apparatus (4) of said structure, after spraying a fumigant, air or an inert gas from a gas container (6) is processed from said nozzle member (9). Since it discharges | emits to space, the fumigant which remained in the piping (81) and the nozzle member (9) can be utilized without waste. In the present invention, spraying devices having various structures can be used as long as the fumigant can be sprayed in a mist form and air or inert gas can be supplied after spraying.

Example 1:
By forming a wooden frame and covering it with the sheet (2), two processing spaces having a height of 0.7 m, a frontage length of 2.7 m, and a depth of 1.6 m are formed. , B. Then, 43 pieces of wood (1) having a diameter of about 12 to 20 cm and a length of 1 m were stacked in each of the A and B sections, and the fumigation method of the present invention was carried out in the A section to measure the fumigant concentration distribution. . The concentration of the fumigant was measured by gas chromatography. The atmosphere temperature in the processing space was 20 ° C.

  The spraying device (4) shown in FIG. 2 was used for spraying the fumigant. As the nozzle member (9), one in which one spray nozzle (91) having an expansion angle of 90 degrees and a nozzle diameter of 1.8 mm was arranged was used. The fumigant container (5) was initially filled with 120 g of methyl iodide and pressurized to 0.3 MPa with air. The gas container (6) used was filled with 3.4 liters of air and pressurized to 0.3 MPa.

In area A, the nozzle member (9) is placed in the upper center of the stacked wood (1), the fumigant in the fumigant container (5) is sprayed in 5 minutes, and the gas container ( The air of 6) was supplied to the treatment space. The dosage was 40 g / m ³ . And after completion | finish of a process, when the fumigant density | concentration of each site | part when 1 hour, 3 hours, and 5 hours passed was measured, the result shown in Table 1 was obtained.

Comparative Example 1:
The conventional method was implemented in the B section of the processing space formed in Example 1, and the concentration distribution of the fumigant was measured. In spraying the fumigant, a can filled with 120 g of methyl iodide was used. A saucer was placed on the upper center of the wood, the methyl iodide can was opened and placed on the saucer, and methyl iodide was allowed to flow and vaporize on the saucer. The dosage was 40 g / m ³ . And after completion | finish of a process, when the fumigant density | concentration of each site | part when 1 hour, 3 hours, and 5 hours passed was measured, the result shown in Table 1 was obtained.

  In Zone B, liquid methyl iodide flows out onto the pan simultaneously with opening of the methyl iodide can, so the initial vaporization amount is large. However, after one hour has passed, the average concentration in Section A is 3052 ppm and the average concentration in Section B is 1093 ppm. When more than one hour has passed, vaporization and diffusion proceed more rapidly in Section A than in Section B. is doing. Therefore, a stable insecticidal effect can be expected in the A section compared to the B section. In addition, it is thought that the fumigant density | concentration of the fumigant of A section becomes lower after 3 to 5 hours than after 1 hour because the vaporized fumigant is adsorbed by the wood (1). On the other hand, the fumigant concentration in the B zone is higher after 3 to 5 hours than after 1 hour because methyl iodide is present in liquid form on the saucer and takes a long time for vaporization. Because.

Example 2:
By forming a wooden frame and covering it with the sheet (2), two processing spaces similar to those in Example 1 were formed, and these processing spaces were designated as A and B zones as in Example 1. Then, similarly to Example 1, the wood (1) is stacked in each of the A and B zones, and the spraying device (4) similar to that in Example 1 is used. In the A zone, the present invention is performed under the same conditions as in Example 1. The fumigation method was carried out and the concentration distribution of the fumigant was measured. And after completion | finish of a process, when the fumigant density | concentration of each site | part when 1 hour, 3 hours, and 5 hours passed was measured, the result shown in Table 2 was obtained. The atmosphere temperature in the processing space was 20 ° C.

Comparative Example 2:
In section B of the treatment space formed in Example 2, only the fumigant was sprayed under the same conditions as in Example 1 except that air was not supplied from the gas container (6). And after completion | finish of a process, when the fumigant density | concentration of each site | part when 1 hour, 3 hours, and 5 hours passed was measured, the result shown in Table 2 was obtained.

  At the measurement point in Section A, there was no difference in concentration between the upper part and the lower part. Air was supplied from the gas container (6) immediately after administration of methyl iodide, and the methyl iodide in the pipe (81) was pushed out and treated. This is because methyl iodide in the space was rapidly vaporized and stirred. On the other hand, in the B zone, after 1 hour from the end of the treatment, the concentration of the upper part is lower than that of the lower part. Because.

Example 3:
43 pieces of wood (1) having a diameter of about 12 to 20 cm and a length of 1 m were stacked. At that time, 3 trees in total, one on the upper stage and one on each of the left and right sides of the lower stage, were used as damaged trees (wood in which the larvae of the pinewood beetle were inside). And the nozzle member (9) of the spraying apparatus (4) was arrange | positioned in the upper center of the piled wood (1), and the whole wood (1) was covered with the sheet | seat (2) with the nozzle member (9). Next, methyl iodide was sprayed as a fumigant under the same conditions as in Example 1, and air was supplied under the same conditions as in Example 1. And during 24 hours, the fumigant density | concentration of the center upper part of the piled wood (1) was measured. As a result, changes in concentration as shown in Table 3 were observed. In addition, each damaged tree was taken out after 24 hours, moved to a breeding room where the room temperature was maintained at 26 ° C., and taken out after 10 days to confirm the survival of the larvae. The results shown in Table 4 were obtained. It was. Table 4 also shows the life and death of damaged tree larvae that were not fumigated.

  It was confirmed that the fumigant was rapidly vaporized by spraying the fumigant and supplying air. Then, after spraying the fumigant, by sending air to the inside of the sheet (2), the vaporized fumigant spreads to every corner, and as shown in Table 4, 100% insecticidal effect is obtained. It was done.

It is a longitudinal cross-sectional view which shows the concept of the fumigation method of the wood which concerns on this invention. It is an assembly drawing which shows the structural example of the spraying apparatus applied to this invention.

Explanation of symbols

1: Wood 2: Sheet 4: Spraying device 5: Fumigant container 6: Gas container 7: Joint part 71: On-off valve 72: On-off valve 81: Pipe 82: Second pipe 9: Nozzle member 91: Spray nozzle

Claims (2)

  A method of fumigating wood with a fumigant containing methyl iodide as an active ingredient, wherein a nozzle member of a spraying device is arranged on top of the stacked wood, and the wood is covered with a sheet together with the nozzle member, from the nozzle member After spraying the fumigant, air or an inert gas is sent from the nozzle member. As a spraying device, a fumigant container filled with a fumigant and capable of extruding the fumigant with an internal compressed gas, and a nozzle provided at the end of a pipe extended from the fumigant container and spraying fluid in a mist form A gas container filled with air or an inert gas and connected to the base of the pipe on the fumigant container side through a second pipe, and the spray of the fumigant and air or an inert gas The wood fumigation method according to claim 1 , wherein a spraying device configured to be able to switch between air feeding is used.

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