JP2006123141A - Mixed air jet injector and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mixed air jet injector and its method, capable of performing surface treatment and cleaning of an object, without generating rust, even when aiming at a metallic material such as a steel structure and a steel material. <P>SOLUTION: This mixed air jet injector is composed of a mixed air jetter 2 having a jet nozzle 8 on the tip, a nitrogen gas cylinder 3 for supplying nitrogen gas under high pressure to this mixed air jetter 2, and a high pressure pump 5 for supplying liquid under high pressure to the mixed air jetter 2; and is constituted so as to inject the liquid reduced in the dissolved oxygen concentration by substitution of the nitrogen gas in a droplet-formed state from the jet nozzle 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air-jet injection method and an apparatus for the same, in which an air-fuel jet in which a liquid and a gas are mixed is jetted onto an object to be processed, and surface modification or cleaning of the object to be processed is performed.

  Conventionally, blasting has been performed as a base adjustment before painting of a steel structure or a steel material, or as a friction bonding surface treatment. There are various types of blasting methods, which are roughly classified into dry blasting and wet blasting. Of these, dry blasting includes centrifugal blasting (a method in which abrasives are projected by the centrifugal force of a rotating disk) and air blasting (a method in which abrasives are supplied to the flow of compressed air and injected from a nozzle). There is.

  On the other hand, for wet blasting, water jet blasting (a method in which abrasive is added to high-pressure water and sprayed as a jet water stream), compressed air, water (high-pressure water), and abrasives are supplied to an air-jet jetter. There is an air-jet jet blast in which water is made into droplets by water and compressed air and an abrasive are sprayed together with the water in droplets (for example, JP-A-2002-79145).

  In addition, the jet cleaning device supplies water jet cleaning device (a system that injects high-pressure water as a jet water flow) and compressed air and water (high-pressure water) to an air-fueled jetter. There is an air-jet cleaning device that blows compressed air together with water in a droplet state (for example, JP-A-2002-79145).

JP 2002-79145 A

  In dry blasting, dust is scattered at the time of construction. Therefore, means for dealing with dust scattering is required at the time of construction. On the other hand, since wet blasting adds an abrasive to the water jet, it can prevent dust from scattering. However, since water is used, rust may occur when applying to pre-painting treatment of steel structures and steel materials. In this case, the required quality such as substrate preparation before painting is obtained. There is a problem that can not be.

  In addition, as a rust prevention measure in wet blasting, a method of using an inhibitor (corrosion inhibitor) (mixed in water) is also applied, but because it is toxic, it must be properly recovered during construction. Become. In addition, after drying, the inhibitor remains on the construction surface in the form of a film, which may adversely affect the subsequent coating process. Therefore, there is a problem in using the inhibitor when wet blasting is to be applied to preparation of a base material before coating such as steel.

  In addition, because “the high dissolved oxygen concentration of the water used” is the cause of rust, if the dissolved oxygen concentration of water used for wet blasting is reduced by applying a known dissolved oxygen reduction method, It is considered that rust can be prevented, but when applying the dissolved oxygen reduction method to a conventional wet blasting apparatus, there are various obstacles in terms of practicality, and practical application is difficult.

  More specifically, among the known methods for reducing dissolved oxygen, the “nitrogen gas replacement method”, which is said to be the most efficient, is a method in which nitrogen gas is bubbled into water in a tank and stirred for 10 minutes or more using a stirrer. By replacing the dissolved oxygen with nitrogen gas, this method has a problem that the work process takes time, and if the water is used up during the blasting operation, There is a problem that the blasting operation cannot be continuously performed because the water in which the dissolved oxygen is reduced must be prepared.

  In addition, in conventional jet cleaning equipment, even when cleaning dirt such as steel, oil, etc., or when peeling the surface coating, etc., dissolved oxygen is high because of the presence of air and water. There is a problem that rust is easily generated on the surface.

  The present invention has been made to solve such problems of the prior art, and even when a metal material such as a steel structure or a steel material is targeted, the object is not generated. It is an object of the present invention to provide an air-jet jet apparatus and method for performing surface treatment and cleaning of an object.

  An air-fuel mixture jet injection apparatus according to the present invention comprises an air-fuel mixture jetter having a jet nozzle at its tip, a nitrogen gas supply means for supplying nitrogen gas to the air-fuel mixture jetter at high pressure, and a liquid to the air-fuel mixture jetter at high pressure. The high-pressure liquid supply means is configured such that a liquid having a dissolved oxygen concentration reduced by nitrogen gas replacement can be ejected in a droplet state from a jet nozzle.

  The air-fuel mixture jet injection apparatus can also be configured such that an abrasive supply means for supplying an abrasive is connected to a gas supply passage for supplying nitrogen gas from the nitrogen gas supply means to the air-fuel mixture jetter.

  The mixed gas jet injection method of the present invention supplies a high pressure nitrogen gas from a nitrogen gas supply means to a mixed gas jetter having a jet nozzle at the tip and also supplies a high pressure liquid from the high pressure liquid supply means. By mixing the liquid, the dissolved oxygen concentration of the liquid is reduced by nitrogen gas replacement, and the nitrogen gas and the liquid are ejected from the jet nozzle in a droplet state.

  In this mixed gas jet injection method, the abrasive may be supplied into the nitrogen gas supplied from the nitrogen gas supply means.

  The mixed-air jet injection device of the present invention can perform surface treatment and cleaning of an object without generating rust even when a metal material such as a steel structure or steel material is targeted.

  Moreover, according to the mixed-air jet injection method of the present invention, surface treatment and cleaning of an object can be performed without generating rust even when a metal material such as a steel structure or steel material is targeted. Can do.

  Hereinafter, preferred embodiments of the present invention will be described. FIG. 1 is a configuration diagram of a jet blasting apparatus 1 according to the present invention. As shown in the figure, the jet blasting apparatus 1 includes an air-fuel mixture jetter 2, a nitrogen gas cylinder 3, a liquid tank 4, a high-pressure pump 5, and an abrasive supply device 6.

  The mixed gas jetter 2 has a mixed gas jet nozzle 8 at the tip, and nitrogen gas is supplied to the mixed gas jetter 2 from the nitrogen gas cylinder 3 through the gas supply passage 21 at a predetermined pressure (0.5 MPa). Furthermore, the water or tap water stored in the liquid tank 4 is supplied at a high pressure via the high-pressure pump 5 provided in the liquid supply passage 22. Yes.

  Further, the abrasive supply device 6 has a fixed amount feeding device 7 below, and the abrasive (sand, etc.) accommodated therein passes from the nitrogen gas supply passage 21 via the abrasive supply passage 23. It is quantitatively supplied to the mixed gas jetter 2 together with nitrogen gas.

  The high-pressure water supplied to the mixed gas jetter 2 is a liquid nozzle 2a provided in the internal space of the mixed gas jetter 2 as shown in FIG. 2 (a diagram showing the internal structure of the mixed gas jetter 2 shown in FIG. 1). The high-pressure nitrogen gas that has been jetted into the air-fuel mixture chamber 2b at a high speed from the gas nozzle 2c is similarly jetted into the air-fuel mixture chamber 2b at a high speed from the gas nozzle 2c, whereby water becomes droplets. become. Then, droplet-formed water, abrasive, and nitrogen gas are jetted forward from the tip 8b of the air-mixing jet nozzle 8.

  In this way, mixed air jet blasting can be performed for the purpose of adjusting the pre-painting surface of the construction object by spraying abrasives or the like from the mixed air jet nozzle 8 and spraying it toward the surface to be constructed. it can.

  By the way, when water is brought into contact with a metal material such as steel, rust is generated due to dissolved oxygen in the water. Therefore, as described above, wet blasting is conventionally applied to pretreatment for coating steel. Was difficult. However, when the jet blasting apparatus 1 according to the present invention is used, mixed-air jet blasting can be performed for steel materials and the like without generating rust.

  This point will be described in detail. As shown in FIG. 2, since nitrogen gas flows into the mixed gas chamber 2b of the mixed gas jetter 2 together with water at a high pressure, the liquid is mixed in the mixed gas chamber 2b. The water in the droplet state is exposed to an atmosphere of high-pressure nitrogen gas, thereby performing “nitrogen gas replacement”. Therefore, before the inflow into the mixed gas chamber 2b, even if oxygen is dissolved at a high concentration in water, the "nitrogen gas replacement" is performed in the mixed gas chamber 2b. The dissolved oxygen concentration in the droplet is instantaneously reduced.

  Thus, when mixed-air jet blasting is performed using the jet blasting apparatus 1 according to the present invention, since the dissolved oxygen concentration of water sprayed on the construction target is reduced, the construction target is a steel material or the like. Even if it is the metal material of this, generation | occurrence | production of rust can be avoided effectively. In addition, since “nitrogen gas replacement” is performed instantaneously and continuously, it is preferable to avoid a situation in which the blasting operation is interrupted due to the dissolved oxygen reduction treatment of the water used. And the blasting operation can be performed efficiently.

  FIG. 3 is a configuration diagram of the jet cleaning apparatus 11 according to the present invention. As shown in the figure, the jet cleaning device 11 is constituted by an air-fuel mixture jetter 2, a nitrogen gas cylinder 3, a liquid tank 14, and a high-pressure pump 5, and is different from the jet blasting device 1 shown in FIG. It is not a device for jet blasting, but is mainly used for jet cleaning for metal materials.

  Therefore, unlike the jet blasting device 1 of FIG. 1, the abrasive supply device 6 is not included in the configuration, and a cleaning liquid (detergent or water) is stored in the liquid tank 14. That is, the mixed gas jet nozzle 8 ejects cleaning liquid in a droplet state and nitrogen gas.

  Other points (structure of the mixed gas jetter 2, supply pressure of nitrogen gas, performance of the high pressure pump 5, etc.) are the same as those of the jet blasting device 1 of FIG. 1, and the supplied cleaning liquid is in the mixed gas jetter 2. In FIG. 5, “nitrogen gas replacement” is performed, and the mixed gas jet nozzle 8 injects the dissolved oxygen concentration in a reduced state. Therefore, when jet cleaning is performed using the jet cleaning device 11 according to the present invention, the occurrence of rust can be effectively avoided even if the construction object is a metal material such as steel.

  In addition, when “nitrogen gas replacement” is performed, the dissolved oxygen concentration of water or cleaning liquid is maintained at a low concentration without increasing for at least about 20 minutes, but the dissolved oxygen concentration increases after 20 minutes. And rusting may occur. Therefore, it is desirable to remove the moisture adhering to and remaining on the construction target surface by performing wet blasting or jet cleaning within 20 minutes after construction by compressed air or the like.

The block diagram of the jet blasting apparatus 1 of this invention. The figure which shows the internal structure of the mixed air jetter 2 shown in FIG. The block diagram of the jet-cleaning apparatus 11 of this invention.

Explanation of symbols

1: Jet blasting device,
2: Mixed air jetter,
2a: liquid nozzle,
2b: mixed air chamber,
2c: gas nozzle,
3: Nitrogen gas cylinder,
4, 14: Liquid tank
5: High pressure pump,
6: Abrasive supply device
7: Fixed amount feeding device,
8: Mixed-air jet nozzle,
8b: tip,
11: Jet cleaning device

Claims (4)

An air-fueled jetter having a jet nozzle at the tip, nitrogen gas supply means for supplying nitrogen gas to the air-fueled jetter at high pressure, and high-pressure liquid supply means for supplying liquid to the air-fueled jetter at high pressure,
An air-fueled jet injection apparatus configured to be able to jet a liquid having a dissolved oxygen concentration reduced by nitrogen gas replacement in a droplet state from the jet nozzle.   2. The mixed gas jet injection device according to claim 1, further comprising an abrasive supply unit for supplying an abrasive in a gas supply passage for supplying nitrogen gas from the nitrogen gas supply unit to the mixed gas jetter.   By supplying high-pressure nitrogen gas from the nitrogen gas supply means to the air-fuel mixture jetter having a jet nozzle at the tip, and supplying high-pressure liquid from the high-pressure liquid supply means to mix the nitrogen gas and the liquid, A mixed gas jet injection method, wherein a dissolved oxygen concentration is reduced by nitrogen gas replacement, and nitrogen gas and liquid are jetted from the jet nozzle in a droplet state.   The mixed jet injection method according to claim 3, wherein the abrasive is supplied into the nitrogen gas supplied from the nitrogen gas supply means.