JPH0638038B2 - Scale removing method and apparatus therefor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a scale removing method and apparatus of the present invention, and more specifically, cleaning scales attached to heat transfer surfaces, wall surfaces and other various cleaning surfaces of a combustion chamber of a combustion apparatus. The present invention relates to a scale removing method and apparatus for removing the scale.

[Prior Art] As is well known, radiation of heat transfer surfaces (tubes, drums, etc. that receive radiant heat generated by combustion) of a combustion chamber that constitutes a combustion device (for example, a boiler for land or ship, an incinerator, etc.) There is a heat transfer surface or a contact heat transfer surface such as a tube for contact heat transfer with combustion gas.), And a wall made of refractory bricks or the like forming the combustion chamber or other cleaning surface has scale, slag, soot, etc. Adhere to.

If the scale or the like adheres and the heat transfer surface becomes dirty, the thermal efficiency is reduced, and many problems such as overheating of the combustion chamber occur. Therefore, it has been practiced to clean and remove the scale regularly or whenever the scale adheres.

As a means for removing scale etc. that has been conventionally used as a means for this, scrape off with hand tools,
Alternatively, a water soaking method using high-pressure water, a shot blast cleaning method of spraying small particles such as steel balls or sand, etc. are used.

[Problems to be Solved by the Invention] Although the above-mentioned conventional techniques have many achievements, they still have problems in the following points. That is, cleaning using a hand tool is simple but the cleaning work efficiency is poor. On the other hand, although the water soaking method using high-pressure water can improve the cleaning efficiency, water permeates into the refractory material such as the wall surface, which easily causes erosion and corrosion, which lowers the durability. or,
The shot blast method has an advantage that it can be efficiently cleaned without the above-mentioned problems of erosion and corrosion. However, in this case, the particles to be sprayed easily enter the concave portions of the surface for cleaning such as the heat transfer surface or the wall surface, and the particles cannot be removed. Conventionally, non-combustible particles such as steel balls and sand are used as the particles to be sprayed in order to remove the adhered scales as described above. If they adhere to the surface, the particles themselves used for cleaning hinder heat transfer. Therefore,
The granules used to remove the scale and the like had to be sufficiently removed, and it was difficult to dispose of them.

The present invention was made in view of the above points, and the object of the present invention is that it can be cleaned well, does not corrode or corrode, and is easy to dispose of sprayed granules. The present invention provides a scale removing method and a device for such a combustion apparatus.

[Means for Solving Problems] The present invention has the following technical means for achieving the above object. That is, the present application does not grind plant grains such as walnuts, or those in which combustible plant solid particles having a relatively small coefficient of repulsion such as seeds are finely pulverized, or when they themselves are pulverized. The scale removing method is characterized in that they are placed on a high-speed air stream and jetted onto the surface of the object to be cleaned, and an apparatus for use in the method.

[Operation] Since the present invention comprises the above technical means, when the plant solid particles are blown onto the cleaning target surface to which the scale adheres by applying a high-speed air flow, the plant solid particles hit the scale to clean the heat transfer surface and the like. It can be removed from the surface. Since the above-mentioned plant solid particles have a characteristic that the coefficient of restitution is small, they do not immediately fly off when hitting a cleaning target surface such as a heat transfer surface, and sufficiently hit the surface to hit the scale. Since it is repelled from the beginning, the scale can be removed well from the surface.

Further, since the above-mentioned plant solid particles are flammable, when they are used for cleaning the heat transfer surface or wall surface of the combustion device, such as the cleaning target surface, they enter the recesses and can be recovered. Those that were not burned out by the combustion of the combustion device. Therefore, the disposition becomes good.

[Embodiment] Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1 of the accompanying drawings, A indicates a cleaning target surface to which the scale B is attached, and C indicates an injection nozzle.

Various objects are considered as the cleaning target surface A, and examples thereof include a heat transfer tube of a combustion device (boiler, incinerator, etc.), a fireproof wall surface, a wall surface of a dust collection chamber, and the like.

Conventionally, in such a thing, high-pressure water, sand or the like was blown from the jet nozzle C, but in the case of the present invention, a combustible plant solid particle having a relatively small coefficient of restitution. D is used, and the plant solid particles D are placed on the high-speed air stream E and sprayed from the jet nozzle C onto the cleaning target surface A.

Examples of the plant solid particles D include walnut grains that are finely divided into pieces, rice, other seeds themselves, or finely obtained grains thereof.

When the scale is cleaned in this way, the solid particles of the plant have a relatively small coefficient of restitution compared with steel balls, so when the cleaning target surface A is hit, the scale B is scraped off and removed. Efficient.

Then, the plant solid particles D after once used are collected and reused by using a vacuum suction device or the like.

In the above-mentioned use, even if the plant solid particles D get into the concave portion or the like of the cleaning target surface A, they can be easily collected by suction by the vacuum suction device. In particular, when the cleaning target surface is a heat transfer tube or a fire resistant surface of the combustion device, even if the cleaning target surface enters the recesses, they are burned out in the subsequent combustion, so that it is easy to clean up.

In the above method, an apparatus for carrying out this is
The above-mentioned plant solid particles D and the nozzle device C capable of being sprayed onto the high-speed airflow E are provided, but any means for mixing the plant solid particles D into the high-speed airflow E may be used.

Next, a first application example of the present invention will be described with reference to FIGS. In the case of this application example, an example is shown in which walnut grains are finely crushed as the plant solid particles.

In FIG. 1, reference numeral 1 denotes a scale removing device, which is constructed on a carriage 2 as follows. That is, the average grain size is 5 on the trolley 2.
A tank 4 for accommodating walnut grains 3 crushed to about m / m to 1 m / m is provided. The tank 4 has a capacity of about 100, for example, and a hopper 5 for putting walnut grains is provided on the upper portion. A wire mesh 6 is provided in the hopper 5 so that large particles or dust that may be clogged with valves or nozzles described later do not enter. A closing valve body 7 is arranged in the opening formed in the upper part of the tank 4, and when the compressed air is supplied into the tank 4, the closing valve body 7 closes the opening communicating with the hopper 5. It is like this.

A walnut supply valve 16 is arranged at the lower end of the tank 4, and the walnut grains 3 accommodated in the tank 4 are sucked by the ejector 8 through the walnut supply valve 16 and the walnut blast hose 9. It is designed to be sent to the spray nozzle 17. The high pressure air for injecting the walnut grains 3 from the blowing nozzle 17 is the compressor 10
Is supplied to the drain separator 11 arranged on the carriage 2. As the compressor 10, for example, it is desirable to use a compressor having a normal pressure of 7 kg / cm ² and a discharge air amount of about 5 m ³ / min. In the present embodiment, an example is shown in which compressed air is sent from the compressor 10 to the drain separator 11 using the main hose 12 and the auxiliary hose 13.

An air filter 14 is provided on the downstream side of the drain separator 11.
The air filter 14 is used to remove dust, water droplets, oil, etc. in the air. A compressed air supply pipe 15 is connected to the air filter 14, the compressed air supply pipe 15 is branched into two in the middle, and one of the supply pipes 15a is connected to the tank 4. The other supply pipe 15b is joined to the outlet of the walnut supply valve 16 connected to the ejector 8, and the walnut blast hose 9 is connected to this outlet.

The other feeding pipe 15b is a branch pipe 18a, 18b
Is once forked. And this branch pipe
An injection actuating air valve 19 for controlling the injection operation of the ejector 8 is provided in 18a, and the branch pipe 18b is used to wipe out the remaining walnuts in the blast hose after the work is completed and when the work is interrupted for a relatively long time. An air bypass valve 20 is installed for this purpose. The above shows the main flow of high-pressure air jetted from the blowing nozzle 17, and the tank 4
The spraying of the walnut grains 3 housed inside can be controlled by the spray nozzle 17.

That is, the operating air hose 21 is led out from the air filter 14, and the operating air hose 21 is connected to the remote control key 22 arranged on the spray nozzle 17. The operation air hose 21 includes an operation air filter regulator 23a and an operation air secondary filter 23b.
Is installed so that dust and the like contained in the air are removed and the pressure is adjusted to a predetermined pressure. Reference numeral 24 is a control box also provided in the operation air hose 21. An operation air switching valve is provided inside, and a primary side inlet 25a, a primary side outlet 25b, and a secondary side inlet are provided. 26a and a secondary outlet 26b are provided. The operating air hose 21 from the air filter 14 is connected to the primary side inlet 25a and the primary side outlet 25b.
The inlet side of the remote control key 22 arranged on the spray nozzle 17 is connected. Further, the outlet side of the remote control key 22 and the secondary side inlet 26a of the control box 24 are connected, and the operation air hose 21 connected to the secondary side outlet 26b is the walnut supply valve 16 and the injection operation air valve.
19 are connected via speed control valves 27 and 28, respectively.

Next, 29 is an auxiliary air supply pipe, and an air filter 14
Is provided to feed the air from the inside of the walnut supply valve 16 to the lower part of the tank 4 so as to prevent the walnut seeds from causing a bridge phenomenon in the walnut tank and to control the amount of walnuts flowing out from the tank. It has become.

Reference numeral 30 in the drawing denotes an on-off valve provided in each pipe for interrupting the flow of high-pressure air.

Next, the operation based on the above embodiment will be described.

When the scale removing device 1 of the above embodiment is used, the compressor 10 is driven to supply high pressure air to the drain separator.
Supply to 11. After supplying the high-pressure air into the drain separator 11, the open / close valve 30 --- is opened to put the scale removing device 1 into an operating state. By opening the opening / closing valve 30, high-pressure air is supplied into the tank 4 to increase the pressure in the tank 4, and the closing valve body 7 arranged in the upper part of the tank 4 rises to increase the tank 4 and the hopper. Make 5 unconnected.

As a result, the scale removing device 1 is activated, but the walnut grains 3 are not yet sprayed from the spray nozzle 17. When the walnut grains 3 are sprayed from the spray nozzle 17, the remote control key 22 provided on the spray nozzle 17 is operated. The operation air switching valve arranged in the control box 24 is switched by the operation of the remote controller 22, and the operation air is supplied to the injection operation air valve 19 and the walnut supply valve 16. A branch pipe when the operating air is supplied to the injection actuating air valve 19.
High-pressure air flows into 18a, the ejector 8 operates, and the walnut supply valve 16 opens. For this reason, the walnut grains 3 housed in the tank 4 are sucked into the ejector 8 via the walnut supply valve 16 and placed on the flow of this high-pressure air as shown by the arrow 31 in FIG. It can be jetted from the tip of the spray nozzle 17. In this way, the walnut grains 3 sprayed from the tip of the spray nozzle 17
By spraying the heat transfer surface 33 and the wall surface 34 of the boiler 32 as shown in the figure, the scale 35 adhering thereto can be removed. Since the walnut grain 3 has a small coefficient of restitution, the repulsive force when sprayed on the heat transfer surface 33 is small. Therefore, it is possible to firmly abut on the surface such as the heat transfer surface 33. That is, when the repulsive force is large, the surface is often repelled, but when the repulsive force is small, the surface is allowed to slide. Therefore, it is possible to remove the scale 35 adhering to the surface by dropping it too much. Therefore, the scale adhering to the heat transfer surface 33 can be removed well, and the cleaning efficiency can be improved.

The walnut grains 3 used for removing the scale 35 as described above can be recovered by using a device such as a vacuum cleaner and used at the next cleaning. Since it can be collected and used as many times as described above, the cleaning cost per cleaning can be reduced.

In this way, the walnut grains 3 used to remove the scale 35 are collected after cleaning, but the heat transfer surface 33 and the wall surface.
It is difficult to collect walnut grains 3 whose 34 recesses have entered the gap. Collecting such a thing takes time and labor, and cleaning efficiency falls. However, in the case of conventional shot blasting, since non-combustible particles, that is, steel balls and sand, were sprayed, those that have entered recesses or gaps must be collected as much as possible. This is because the particles themselves impede heat conduction as described above.

However, in the present case, since the walnut grains 3 are flammable, it is not necessary to intentionally collect those that are difficult to collect because they have entered the recesses or gaps. This is because the walnut grains 3 are burnt out by combustion and do not hinder heat conduction. That is, it is possible to easily clean up after removing the scale and improve the cleaning efficiency.

Next, a second application example of the present invention will be described with reference to FIGS.

The high pressure air flows from the compressor 101 to the drain separator 102,
On the other hand, finely crushed walnut grains and plant solid particles 105 such as rice grains are fed through the supply pipes 103 and 104, and fed into the supply pipe 104 through a hopper 106 and a rotary valve 107. Therefore, the plant solid particles placed in the high-speed air flow reach the nozzle 109 via the hose 108 as in the previous example, and are sprayed from there to the cleaning target surface 110 to remove scale and the like. In the case of this example as well, a configuration is adopted in which the injection operation air valve 113 can be opened / closed and remotely controlled by the control of the control unit 112 by the remote control key 111.

Now, the plant solid particles sprayed on the cleaning target surface 110 and used for removing the scale fall downward due to gravity, and are sucked and collected by the vacuum hose 114 with the strainer 115.

That is, in this example, high pressure air from the compressor 101
It is fed to the walnut recovery ejector 117 via 16 and the pipe 119 of the vacuum hose 114 is connected to the suction portion 118 of the ejector 117. Therefore, 9 plant solid particles such as walnut grains are sucked and collected by the ejector action of the ejector 117, and the hose
It is sucked into the cyclone 121 and the recovery tank 122 via 120.

From the recovery tank 122, a predetermined one that has been dropped onto the vibrating sieve 124 via the rotary valve 123 and selected is put into the hopper 105.

As in this example, the injection of plant solid particles and the collection after use can be combined in one loop.

The example of FIG. 5 shows one example of the place where cleaning is performed using the example of FIG. 4, that is, the refuse incinerator 12
In the example shown in FIG. 5, scale attached to the boiler heat transfer tube 126, the wall surface 127 of the furnace chamber, the gas cooling chamber 128, the wall surface 129 of the dust collection chamber, and the like can be removed.

[Effect of the Invention] As described in detail above, according to the present invention, since the plant solid particles having a small coefficient of restitution are used, the sprayed plant solid particles or the like slide on the surface for cleaning. Since it repels, it is possible to clean and remove the scale etc. adhering to the surface well, and since there is no water, there is no problem of eroding or corroding the combustion device, and this was used for the combustion device If the plant solid particles are flammable,
Since it is not necessary to remove what has entered the recesses or gaps, it is easy to dispose of the sprayed granules, and various advantages such as providing a scale removing method and its device that can improve cleaning efficiency are provided. Have.

[Brief description of drawings]

The attached drawings show an embodiment of the present invention, FIG. 1 is a basic conceptual diagram, FIG. 2 is a system diagram of the first embodiment, FIG. 3 is a use example diagram of FIG. 2, and FIG. Example system diagram, FIG. 5 is the fourth
It is a usage example figure of an example of a figure. In the figure, A ... cleaning surface, B ... scale, C ... injection nozzle, D ... plant solid particles such as walnut grains, E ... high-speed air flow,

Claims (2)

[Claims] 1. A method for removing scale, in which solid particles are sprayed onto a cleaning object to remove scales, slag, etc. attached to it, in comparison with plant grains such as walnuts and seeds. Combustible plant solid particles with small repulsion coefficient and flammability are finely pulverized, or if they are themselves finely pulverized, they are not pulverized, and they are placed on a high-speed air stream and sprayed onto the surface of the cleaning object. The scale removal method is characterized in that the scale is removed accordingly. 2. A scale removing device having a nozzle for spraying solid particles onto a cleaning object by applying a high-speed air flow; as the solid particles sprayed from the nozzle, plant grains or seeds such as walnuts. A scale removing device characterized in that flammable plant solid particles having a relatively small coefficient of repulsion such as, for example, are finely pulverized, or if they are themselves finely pulverized, they are unpulverized.