TWI835687B - Spraying device and blasting materials - Google Patents

Abstract

The present invention is a spraying device equipped with an injector, which can suppress the deterioration of the spraying effect and ensure a predetermined amount of powder spraying. The blasting device (1) of the present invention is provided with a storage means (20) for storing powder (10), an injector (30), and a transfer pipe (40) for transporting the mixture generated by the injector. and an injection means for injecting the aforementioned mixture conveyed through the conveyance pipe (40). The ejector (30) is provided with: a container portion (31) having an internal space connected to the extraction port (21) of the storage means (20); and a discharge nozzle (32) for discharging the pressurized carrier gas from the front end. It is ejected toward the aforementioned internal space; the front end of the ejection nozzle (32) is located closer to the transfer pipe (40) than the vertical center line (A) passing through the center of the extraction port (21), and from the ejection nozzle (32) The shortest distance (Y) from the tip to the inner surface of the container part (31) is included in the range satisfying 2X≦Y≦4.19ln(X)+26.74 when the maximum particle diameter of the powder is set to X. The maximum particle size of the powder (10) is 0.03 mm or more and 5 mm or less.

Description

Spraying device and blasting materials

The present invention relates to a blasting device for blasting using powder, and a blasting material used as the powder in the blasting device.

It is known that a spraying device using powder for spraying is equipped with an injector that can mix the powder and the carrier gas into a mixture (for example, Patent Documents 1 and 2). This type of injection device generates a suction flow in the internal space of the container portion of the injector by the flow of pressurized carrier gas ejected from the front end of the ejection nozzle. And the powder is extracted from the internal space of the container part by this suction flow, is conveyed toward the conveyance pipe, and is injected from the injection means. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2007-275816 [Patent Document 2] Japanese Patent No. 5814699

[Problem to be solved by the invention]

The inventors of the present invention conducted several spraying tests using this spraying device and found that as the particle size of the spraying material, that is, the powder, increases, the powder will clog the internal space of the container portion of the injector. Between the tip of the discharge nozzle and the inner surface of the container part, a problem occurs that sufficient suction flow, that is, the spray effect cannot be obtained. If a sufficient injection effect cannot be obtained, the suction amount of powder in the injector will be reduced. As a result, the amount of powder ejected from the injection means will be reduced, and the prescribed amount of powder ejection cannot be ensured.

The problem to be solved by the present invention is to ensure a predetermined amount of powder injection while suppressing the deterioration of the injection effect in an injection device equipped with an injector. [Technical means used to solve problems]

The present inventors found that the biggest factor causing the deterioration of the spraying effect in a spraying device equipped with an injector is that, as mentioned above, the powder clogs the tip of the discharge nozzle and the inner surface of the container in the inner space of the container of the injector. In order to understand the relationship between the two, we focused on the relationship between the distance from the tip of the discharge nozzle to the inner surface of the container and the maximum particle size of the impact material, that is, the powder, and conducted multiple impact tests. As a result, it was found that when the maximum particle diameter of the powder is set to The range of 26.74 can suppress the decline of the spray effect.

That is, according to one aspect of the present invention, the following spray device can be provided. The spraying device sprays a mixture of powder with a maximum particle diameter of 0.03 mm to 5 mm and a carrier gas, and is provided with: a storage means to store the aforementioned powder and an extraction port for extracting the powder; and an ejector that attracts the powder by the flow of pressurized carrier gas and mixes the carrier gas and the powder to form the mixture; and a transport pipe that transports the mixture generated by the ejector; and an injection means for injecting the mixture conveyed through the conveyance pipe; the injector is provided with: a container part having an internal space connected to the extraction port; and an ejection nozzle for injecting the pressurized carrier gas from The front end of the discharge nozzle discharges toward the internal space; the front end of the discharge nozzle is located closer to the transfer pipe side than the vertical center line passing through the center of the extraction port, from the front end of the discharge nozzle to the inner surface of the container part The shortest distance Y is included in the range satisfying 2X≦Y≦4.19ln(X)+26.74 when the maximum particle diameter of the aforementioned powder is set to X.

According to another aspect of the present invention, there is provided a blasting material used as the powder in the blasting device of the present invention, and the compression degree of the blasting material is 32% or less. [Effects of the invention]

According to the present invention, a spraying device equipped with an injector can suppress a decrease in the spraying effect and ensure a predetermined amount of powder sprayed.

In FIG. 1 , a side view shows an embodiment of the present invention, that is, the overall structure of a spraying device 1 . In FIG. 2 , the main part of the spraying device 1 is shown in a vertical section. The blasting device 1 is provided with a hopper 20 as a storage means for storing the blasting material, that is, the powder 10, an injector 30, a transport pipe 40, and a spraying means 50.

The composition of the powder 10 is determined according to the type of blasting construction performed by the blasting device 1 , that is, according to the type of blasting material. For example, in the case of blasting materials for spray construction in the above-mentioned Patent Documents 1 and 2, the composition of the powder 10 mainly includes combustible powder and refractory powder. When the blasting material is a blasting material for dry blasting construction, the composition of the powder 10 mainly includes refractory powder. Furthermore, when the blasting material is a blasting material for dry sealing construction, the composition of the powder 10 mainly includes refractory powder and glass frit powder. In addition to the above-mentioned main powder, the powder 10 may also contain a binder, a dispersant, and an additive as a snap agent as needed. In any case, the maximum particle size of the powder 10 is 0.03 mm or more and 5 mm or less. That is, the particle size of the powder 10 is such that all of it can pass through a sieve with an opening size of 5 mm, and at least part of it cannot pass through a sieve with an opening size of 0.03 mm. In addition, in this embodiment, the blasting material stored in the hopper 20 includes fibers in addition to the powder 10, and the fibers are not regarded as powder. Therefore, the above-mentioned evaluation of the maximum particle size of the powder 10 excludes fibers.

In this embodiment, the compression degree of the powder 10 is preferably 32% or less. The degree of compression here is obtained by the following equation. Compression degree (%)={(close packing density-sparse packing packing density)/close packing packing density}×100 Furthermore, as described above, in this embodiment, the blasting material includes fibers in addition to the powder 10. However, the evaluation of the compression degree of the powder 10 described above only involves the powder and excludes the fibers.

Next, the device structure of the blasting device 1 will be described. The hopper 20 has an extraction port 21 for extracting the powder 10 at its bottom. The injector 30 sucks the powder 10 from the extraction port 21 by the flow of the pressurized carrier gas, and mixes the carrier gas and the powder 10 into a mixture. The transport pipe 40 transports the mixture generated by the injector. The injection means 50 injects the mixture conveyed through the conveyance pipe 40 . In addition, in this embodiment, the transport pipe 40 is composed of a metal horizontal transfer pipe 41 connected to the outlet side of the injector 30 and a rubber hose 43 connected to the outlet side of the horizontal transfer pipe 41 through a joint 42. composition. However, the horizontal transfer pipe 41 may be omitted, and the rubber hose 43 may be directly connected to the outlet side of the injector 30 .

Next, the structure of the injector 30 will be described in detail. The injector 30 is provided with a container part 31 having an internal space connected to the extraction port 21 at the bottom of the hopper 20, and a narrow tip that injects the pressurized carrier gas from the tip towards the internal space of the container part 31. Discharge nozzle 32. In this discharge nozzle 32 , the carrier gas pressurized by a predetermined pressure is supplied through the carrier gas supply pipe 60 , and the pressurized carrier gas is discharged from the nozzle hole at the front end of the discharge nozzle 32 . That is, the injector 30 generates a suction flow in the internal space of the container portion 31 by the flow of the pressurized carrier gas ejected from the tip of the ejection nozzle 32 . The ejector 30 mixes the sucked powder 10 and the carrier gas into a mixture in the internal space of the container part 31 by this suction flow, and transports the mixture toward the transfer pipe 40 . To explain the function of the injector 30 in more detail, in the internal space of the container part 31, the pressurized carrier gas flows from the nozzle hole at the front end of the ejection nozzle 32 with a narrow front end toward the outlet side of the injector 30. That is, it is sprayed toward the base end side of the conveyance pipe 40 at high speed, thereby making the pressure of the internal space of the container part 31 lower than the atmospheric pressure, thereby generating a suction flow. On the other hand, the extraction port 21 of the hopper 20 communicates with the internal space of the container part 31 through the vertical transfer pipe 70 . Therefore, in the injector 30, the powder 10 is sucked from the extraction port 21 toward the internal space of the container portion 31 by using the suction flow generated by the flow of the pressurized carrier gas, so that the powder 10 and The carrier gas ejected from the nozzle hole at the tip of the ejection nozzle 32 is mixed into a mixture in the internal space of the container portion 31 , and the mixture is transported toward the transport pipe 40 .

As shown in FIG. 2 , in the injector 30 , the tip of the discharge nozzle 32 is located closer to the transport pipe 40 than the vertical center line A passing through the center of the extraction port 21 . In addition, in the injector 30, the shortest distance Y from the tip of the ejection nozzle 32 to the inner surface of the container part 31 is included in the equation satisfying 2X≦Y≦4.19ln (when the maximum particle diameter of the powder 10 is set to X)+26.74 range. In addition, in the spray device 1 of this embodiment, the shortest distance Y is the length from the lower side of the front end of the discharge nozzle 32 to a perpendicular line perpendicular to the lower inner surface of the container portion 31 .

To explain in detail from the embodiment, the above-mentioned shortest distance Y in the spraying device 1 is included in the range satisfying 2X≦Y≦4.19ln(X)+26.74, thereby suppressing the decrease in the spraying effect and ensuring Specified powder injection volume. That is, if the shortest distance Y is smaller than 2X, the powder 10 is likely to become clogged between the tip of the discharge nozzle 32 in the internal space of the container part 31 and the inner surface of the container part 31, and a sufficient suction flow cannot be obtained. Jet effect. If a sufficient injection effect cannot be obtained, the suction amount of the powder 10 in the injector 30 will be reduced. As a result, the powder injection amount ejected from the injection means 50 will be reduced, and the predetermined powder injection amount cannot be ensured. On the other hand, if the shortest distance Y is larger than 4.19ln(X)+26.74, it will be difficult to lower the pressure of the internal space of the container portion 31 to lower than the atmospheric pressure. As a result, a sufficient suction flow or injection effect will not be obtained. Therefore, similarly to the case where the shortest distance Y is smaller than 2X, the suction amount of the powder 10 in the injector 30 is reduced. As a result, the injection amount of the powder ejected from the injection means 50 is reduced, making it impossible to ensure the specified requirements. The amount of powder sprayed.

Here, in order to generate a sufficient suction flow in the injector 30, it is preferable to increase the flow rate of the carrier gas from the tip of the discharge nozzle 32 to the discharged carrier gas. Therefore, the pressure of the carrier gas is preferably 0.1 MPa or more. The upper limit of the pressure of the carrier gas is not particularly limited, but a general upper limit is about 1.0 MPa. In addition, the type of carrier gas is determined according to the type of blasting construction to be performed by the blasting device 1 . For example, in the case of spray construction as described in Patent Documents 1 and 2 mentioned above, oxygen gas is typically used as the carrier gas. In the case of dry blasting construction and dry sealing construction, air is typically used as the carrier gas.

Moreover, the smaller the inner diameter Z of the conveyance pipe 40 is, the more likely it is that the powder 10 in the conveyance pipe 40 will be clogged. On the other hand, as the inner diameter of the conveyance pipe 40 becomes larger, the conveyance pressure of the mixture containing the powder 10 decreases, so the powder 10 tends to settle on the lower side of the conveyance pipe 40 , resulting in a decrease in the uniformity of the conveyance. possibility. Therefore, the inner diameter Z of the transport pipe 40 is preferably included in the range satisfying 2X≦Z≦6X. In addition, as shown in FIG. 2 , the inner diameter Z of the transport pipe 40 does not necessarily need to be fixed. When the inner diameter Z of the transport pipe 40 is not fixed, it is preferable that all the inner diameters Z be included in the range satisfying 2X≦Z≦6X.

Furthermore, it is preferable to perform sandblasting on the inner surface of the hopper 20, which is the storage means for the powder 10. Sandblasting refers to a surface treatment in which fine balls or balls with acute angles are sprayed toward a surface to be treated (in the case of the present invention, the side of the steel material that becomes the inner surface of the hopper 20) to form fine unevenness on the surface to be treated. . By applying such sandblasting treatment to the inner surface of the hopper 20, the sliding movement of the powder 10 in the hopper 20 is improved, and the powder 10 can be uniformly extracted from the extraction port 21 of the hopper 20. This helps suppress the deterioration of the spraying effect in the spraying device 1 .

Furthermore, the compression degree of the powder 10 is preferably 32% or less as mentioned above. Powders with lower compressibility have higher fluidity. Therefore, by setting the compression degree of the powder 10 to 32% or less, clogging of the powder 10 in the injection device 1 becomes less likely, and it is easier to ensure a predetermined amount of powder injection. In addition, the degree of compression of the powder 10 can be adjusted by adjusting its particle size composition and the like. In other words, the particle size structure of the powder 10 is adjusted so that the degree of compression becomes 32% or less.

Here, the predetermined powder injection amount is determined according to the maximum particle size of the powder 10 and the like. For example, when the maximum particle diameter of the powder 10 is 1 mm or more and 5 mm or less, it can be about 1 kg/h or more and 150 kg/h or less. When the maximum particle diameter of the powder 10 is 0.03 mm or more and 1 mm or less, it can be 0.5 kg/h. h or more and less than 120kg/h. [Example]

In the spraying device 1 shown in FIGS. 1 and 2 , a spraying test was performed by varying the maximum particle diameter X and the shortest distance Y of the powder 10 to confirm whether a predetermined powder spraying amount could be ensured. The results are shown in Table 1. In addition, the spraying conditions other than the maximum particle diameter X and the shortest distance Y of the powder shown in Table 1 are all the same. The main spraying conditions are as follows. In addition, the prescribed powder injection amount is different in each example, and the range is about 2 to 30kg/h. ‧Powder composition: alumina-silica material (alumina 60 mass%). ‧Powder compression: 25% ‧Carrying gas pressure: 0.3MPa ‧Type of carrier gas: compressed air ‧Spray impact test time: 0.5h In the evaluation of the powder injection amount in Table 1, when the prescribed powder injection amount can be ensured until the end of the impact test time, it is rated as ○ (good), and the powder injection amount decreases until the end of the impact test time. And when the specified powder injection amount cannot be ensured, it is rated as × (defective).

In FIG. 3 , the evaluation results of the powder injection amount shown in Table 1 are shown graphically, in which the maximum particle size X of the powder is the X-axis and the shortest distance Y is the Y-axis. In the same figure, the straight line Y=2X is an approximate line showing the boundary between Examples 1 to 5 and Comparative Examples 1 to 5 in the upper section of Table 1, and is used to define the lower limit of the shortest distance Y. In the same figure, the curve Y=4.19ln(X)+26.74 is an approximate line showing the intersection of Examples 6 to 10 and Comparative Examples 6 to 10 in the lower section of Table 1, and is used to define the upper limit of the shortest distance Y. That is, if the shortest distance Y is included in the range satisfying 2X≦Y≦4.19ln(X)+26.74, the evaluation result of the powder injection amount becomes ○ (good), that is, the decrease in the injection effect is suppressed.

1: Spraying device 10:Powder 20: Hopper (storage means) 21:Extraction port 30:Injector 31: Container Department 32:Ejection nozzle 40:Transportation tube 41: Horizontal transfer pipe (transfer pipe) 42:Connector 43: Rubber hose (transportation tube) 50:Jet means 60: Carrier gas supply pipe 70:Plumb transfer tube A: vertical centerline Y: shortest distance Z: inner diameter

[Fig. 1] A side view of a spray device according to an embodiment of the present invention. [Fig. 2] A vertical sectional view of the main part of the spraying device of Fig. 1. [Fig. [Fig. 3] A graph of the evaluation results of the powder injection amount. The maximum particle diameter X of the powder is the X-axis, and the shortest distance Y is the Y-axis.

1: Spraying device 10:Powder 20: Hopper (storage means) 21:Extraction port 30:Injector 31: Container Department 32:Ejection nozzle 40:Transportation tube 41: Horizontal transfer pipe (transfer pipe) 42:Connector 43: Rubber hose (transportation tube) 60: Carrier gas supply pipe 70:Plumb transfer tube A: vertical centerline Y: shortest distance Z: inner diameter

Claims (5)

A spraying device, It is to spray a mixture of powder and carrier gas with a maximum particle size of 0.03 mm or more and less than 5 mm. It has: A storage means that stores the aforementioned powder and has an extraction port for extracting the powder; and An injector attracts the aforementioned powder through the flow of pressurized carrier gas, and mixes the aforementioned carrier gas and the aforementioned powder to form the aforementioned mixture; and A transport pipe to transport the aforementioned mixture generated by the aforementioned injector; and Injection means injects the mixture transported through the transport pipe; The aforementioned injector is equipped with: The container part has an internal space connected with the aforementioned extraction port; and A spray nozzle is used to spray the pressurized carrier gas from the front end toward the internal space; The front end of the discharge nozzle is located closer to the transfer pipe than the vertical center line passing through the center of the extraction port, The shortest distance Y from the tip of the discharge nozzle to the inner surface of the container part is included in the range satisfying 2X≦Y≦4.19ln(X)+26.74 when the maximum particle diameter of the powder is set to . Such as the spraying device of claim 1, wherein, The pressure of the aforementioned carrier gas is 0.1 MPa or more. Such as the spraying device of claim 1, wherein, The inner diameter Z of the transport pipe is included in the range satisfying 2X≦Z≦6X. Such as the spraying device of claim 1, wherein, The inner surface of the aforementioned storage means is sandblasted. A blasting material, It is used as the aforementioned powder in the blasting device according to any one of claims 1 to 4, and the compression degree of the blasting material is 32% or less.