JPH11226534A - Method and apparatus for cleaning inside of a narrow metal pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To clean the inside of a narrow metal pipe effectively by fluidizing a chemical cleaning liquid existing in a suction cleaning circuit which is formed by engaging both ends of a bent narrow metal pipe with the supply part and suction part of an inside cleaning apparatus, respectively. SOLUTION: When the inside of a narrow metal pipe 9 is cleaned, one end 10 of the pipe 9 is engaged/connected with a supply part 11 formed at the end of a supply tube 8, a suction part 14 formed at the end of a suction tube 12 is engaged/connected with the other end of the pipe 9 to form a suction cleaning circuit 16. After that, a vacuum pump 7 connected with a protective tank 6 is actuated to fluidize a chemical cleaning liquid 2 in the pipe 9. In this way, the inside of the pipe 9 arranged in the circuit 16 is polished/cleaned efficiently so that the degree of cleaning of the inside of the pipe 9 is increased, preventing an inside plated membrane from being peeled by the leakage of treating liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an inner peripheral surface of a small-diameter metal pipe, particularly a thick-walled small-diameter metal pipe used for a high-pressure fuel injection pipe for a diesel engine, a hydraulic pipe for an automobile, and the like.
The present invention relates to a method and an apparatus for cleaning the inner peripheral surface of a small-diameter metal tube for supplying the metal tube in a clean state.

[0002]

2. Description of the Related Art Conventionally, a thin-walled metal tube used for a small-diameter metal tube, for example, a fuel injection tube for a diesel engine, a hydraulic pipe for an automobile, etc. Penetrates or adheres to the inner peripheral surface of the thin metal tube,
Remaining foreign matter moves in a pipe formed by incorporating a thick-walled small-diameter metal pipe, causing clogging of minute gaps such as injection nozzles and injection valves. However, there is a problem that the product life is shortened due to breakage or the like caused by overloading. In addition, when the processing flaws on the inner peripheral surface of the thick-walled small-diameter metal tube are not sufficiently processed and remain, similarly to the above, in order to shorten the product life, it is necessary to take prompt measures. ing.

As a countermeasure against such a problem, in order to reduce processing flaws remaining on the inner peripheral surface of the thick thin metal tube, the inner peripheral surface of the thick thin metal tube is subjected to precision finishing or shot blasting. And Japanese Patent Application Laid-Open No. 55-12282.
As described in Japanese Patent Publication No. 5 (1993) -1994, in order to apply a residual compressive stress to the inner peripheral surface of the thick-walled small-diameter metal tube, the thick-walled small-diameter metal tube is heated in its entirety. A method has been proposed in which the inner peripheral surface of a thick-walled small-diameter metal pipe is tempered by taking a method such as rapid cooling of the inner peripheral surface of the metal tube to improve the life thereof.

[0004] However, even in the case of a thick-walled thin-diameter metal pipe whose inner peripheral surface is tempered by such a method, it is extremely rare that the pipe is used as it is in a straight pipe state. Bending thin thick metal pipes
In most cases, the piping is completed. By examining the inner peripheral surface of the thick-walled thin-diameter metal pipe that has been tempered as described above and then bent, it has recently been found that the tempered state has been released. Although the reason is not clear, the distribution state of the residual compressive stress applied to the inner peripheral surface in a well-balanced manner is seen by the bending process performed later, and the variation in the distribution of the residual compressive stress causes the change in the distribution of the thick and small diameter. It is considered that a localized stress concentration portion is formed on the inner peripheral surface of the metal tube, which may reduce the service life of the thick-walled small-diameter metal tube.

On the other hand, a conventional method of manufacturing a high-pressure fuel injection pipe, which is a typical example of a thick-walled thin metal pipe, will be described. A mother pipe for a thick-walled thin-walled metal pipe is drawn four to five times. After, cutting,
The inner peripheral surface of the thin-walled metal tube obtained by deburring and air blowing is chemically polished and then washed with water. Thereafter, caps are placed on both ends of the base tube, and surface treatment such as plating of Zn or the like is performed on the outer peripheral surface while the caps are kept. Further, after a fastening nut for mounting is incorporated into the base tube whose outer peripheral surface is plated, the connection end of the base tube is formed into a truncated cone, a truncated circular arc, or a spherical spherical shape to form a connection head. A part is formed, and then the inner peripheral surface of the raw tube is subjected to high pressure injection cleaning with oil. Next, a method has been practiced in which, after the raw tube is allowed to stand vertically for oil cutting, the obtained thick thin metal tube is bent to obtain a final product.

However, even in this case, when the connecting head is formed into a truncated cone, a truncated arc, a spherical shape of an abacus, or when left unattended for oil cutting,
It is recognized that foreign matter enters or adheres to the inner peripheral surface of the metal tube, and foreign matter that has peeled off from the inner peripheral surface of the metal tube due to the bending process may be newly observed. Therefore, a method was proposed in which the chemical polishing liquid was injected at high pressure onto the inner peripheral surface of a thick-walled small-diameter metal pipe that had been subjected to bending and then finished as a final product. As a result, the chemical polishing liquid may leak to the outside from the connection portion of the thick-walled small-diameter metal tube, and such a leakage of the chemical polishing liquid may damage the plating film applied to the outer peripheral surface. Therefore, in order to prevent this, it is necessary to ensure a sufficient sealing property of the connecting portion, which requires a complicated and expensive sealing mechanism. Further, a large pressurizing pump is required for high-pressure injection, and the entire apparatus is increased in size, and there is also generation of foreign matter from the pressurizing pump,
Therefore, this proposal had many major obstacles to the actual operation. As described above, in order to increase the durability of a thick-walled small-diameter metal tube through which a high-pressure fluid flows, a simple processing method for cleaning the inner peripheral surface of the thick-walled small-diameter metal tube, There has been a demand for an apparatus used for the above. Such a demand has naturally been demanded also in a general small-diameter metal pipe.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a thin metal tube, particularly a thick-walled thin metal tube through which a high-pressure fluid flows, with a high durability. An object of the present invention is to provide a method and an apparatus for producing a product in a state in which the inner peripheral surface of a small-diameter metal tube is more efficiently cleaned in order to obtain a large-diameter metal tube.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, in the final step of commercializing a small-diameter metal pipe through which a high-pressure fluid flows on the inner peripheral surface, The chemical polishing liquid is caused to flow into the inside of the small-diameter metal tube by a suction action, and the inner peripheral surface of the small-diameter metal tube is polished and cleaned with the chemical polishing liquid, so that the inner peripheral surface of the small-diameter metal tube is efficiently cleaned. It has been found that the problem can be solved by cleaning, and the present invention has been completed. That is, the first embodiment of the present invention is to sequentially perform a surface treatment step, a head forming step of a connection end, and a bending step of forming the whole into a pipe shape on the raw metal tube for a small-diameter metal pipe, The both ends of the bent small-diameter metal pipe are fitted and connected to a supply section and a suction section of an inner peripheral surface cleaning device for the metal pipe, respectively, to form a suction cleaning circuit, and the suction cleaning circuit is formed. The chemical polishing liquid present therein is caused to flow by a high-pressure suction operation, and the chemical polishing liquid is used to polish the inner peripheral surface of the small-diameter metal pipe provided in the suction cleaning circuit, thereby cleaning the inside of the small-diameter metal pipe to be cleaned. It is characterized by a peripheral surface cleaning method.

A second embodiment of the present invention is an apparatus comprising a supply tank for storing a chemical polishing liquid, a storage tank, a protection tank, and a vacuum pump which are sequentially connected. A supply section detachably fitted to and connected to one end of the small-diameter metal tube is connected to an end of a supply tube extending from the tank, and the fine section is connected to an end of a suction tube extending from the storage tank. A suction unit that is detachably fitted and connected to the other end of the diameter metal tube, and that the supply unit and the suction unit are fitted to one end and the other end of the metal tube, respectively; And a protective tank, and an apparatus for cleaning the inner peripheral surface of a small-diameter metal pipe, in which a suction cleaning circuit including a pipe disposed between the protective tank and the vacuum pump is formed.

In the above inner peripheral surface cleaning apparatus, the supply tank is provided with a measuring device capable of moving up and down with respect to the supply tank, and a predetermined amount of the chemical polishing liquid introduced into the measuring device is removed by the vacuum. A suction is made by a pump to flow the inner peripheral surface of the small-diameter metal pipe, and a fluid discharge port is provided at the bottom of each of the supply tank, the storage tank and the protection tank, and is connected to the fluid discharge port. It is preferable that an on-off valve is provided in the pipe section.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail by taking a thick-walled thin-diameter metal tube as an example. The present invention provides a process for manufacturing a thick-walled small-diameter metal pipe used for a fuel injection pipe for a diesel engine, a hydraulic pipe for an automobile, or the like, in order to maintain a high degree of cleanliness of an inner peripheral surface of the thick-walled small-diameter metal pipe. The present invention provides a processing method and an apparatus used at that time. After a base pipe for a thick-walled small-diameter metal pipe is stretched four to five times as in the related art, cutting, deburring, and air blowing are performed. After performing the surface treatment step by plating with Zn or the like, the truncated cone shape, the truncated arc shape, or the abacus spherical head forming step for the connection end, The inner peripheral surface of the thick thin metal tube bent into a substantial product shape is to be processed, and the inner peripheral surface of the thick thin metal tube is brought into contact with a chemical polishing liquid flowing by suction. It is to let.

In the present invention, the thick-walled small-diameter metal tube to be cleaned by contacting with a chemical polishing liquid flowing by a suction action has a thick-walled small-diameter shape having an outer diameter of 50 mm or less. A steel pipe or a stainless steel pipe, the outer peripheral surface of which is previously subjected to a surface treatment such as Zn plating as necessary as in the prior art, if necessary, and at least one end of the thick thin metal pipe has a truncated conical shape or a truncated circle. It has an arc-shaped or spherical abacus head. A bending process of a predetermined shape is performed on such a thick and small-diameter metal tube. The bending process performed at this time is conventionally used and is not particularly limited, and is performed by a normal hand bending process using a mold and a bending member as disclosed in Japanese Patent Application Laid-Open No. 1-289514. Bending or automatic mechanical bending disclosed in JP-A-62-93029 can be appropriately employed.

One end of the thick thin metal pipe which has been bent as described above is fitted into a supply section provided in a suction cleaning circuit of an apparatus for cleaning the inner peripheral surface of the thick thin metal pipe. Connect
Further, the other end is fitted and connected to a suction unit provided in the suction cleaning circuit of the inner peripheral surface cleaning device to form a suction cleaning circuit, and a high-pressure suction of the chemical polishing liquid in the suction cleaning circuit. The inner peripheral surface of the thick thin metal tube arranged in the suction cleaning circuit is polished, washed and cleaned by the flowing chemical polishing liquid by the operation. in this case,
As a fluid for polishing, cleaning and cleaning the inner peripheral surface of a thick thin metal tube, JASC manufactured by Nippon Surface Chemical Co., Ltd. is used.
It is preferable to use a chemical polishing liquid such as O-6C019 (trade name). In this case, the flow rate of the chemical polishing liquid is comparable to the flow rate observed when a fluid having an ejection pressure of 200 kgf / cm ² flows through the circuit. Vacuum degree 200-700mmH
It is preferable to process with about g.

In the present invention, when the inner peripheral surface of the thick thin metal tube is cleaned by flowing the chemical polishing liquid by a suction operation, the inner peripheral surface of the thick thin metal tube is cleaned. The processing can be performed efficiently, and the chemical polishing liquid is supplied from one end of the thick thin metal tube and a supply portion of a suction cleaning circuit or a connection portion formed by fitting the other end of the thick thin metal tube and a suction portion. There is no danger of leakage to the outside of the system causing corrosion.

The reason why the inner peripheral surface of the small-diameter metal tube can be efficiently cleaned is that the chemical polishing solution is generated from the chemical polishing solution when the chemical polishing solution is injected at a high pressure to the inner peripheral surface of the small-diameter metal tube. When the hydrogen gas bubbles are compressed and caused to flow by a suction operation, the bubbles grow or the number of bubbles increases. In the process of increasing the growth and number of the bubbles, the action of stirring the chemical polishing liquid works, and it can be said that the more the growth and the number of bubbles increase, the greater the stirring action. Therefore, in the present invention, the bubbles are grown by the suction operation and the number is increased. As a result, the stirring action generated in this process is increased, and the aging is caused by the contact with the inner peripheral surface of the small-diameter metal tube (the polishing ability is reduced). The liquid is quickly replaced by an unaged (having polishing ability) liquid that flows while pooling, and the unaged chemical polishing liquid is constantly supplied to the inner peripheral surface of the small-diameter metal tube. It seems that efficiency is improved.

The reason that the chemical polishing liquid does not leak out of the system from the connection part due to the fitting and there is no possibility of causing corrosion is because the chemical polishing liquid flowing inside is sucked, and the sealing property of the connection part is reduced. Is insufficient, the chemical polishing liquid does not leak to the outside, but merely entrains air from the outside into the chemical polishing liquid. Therefore, it is not necessary to provide a special sealing mechanism at the connection portion, and the connection portion can be implemented by a connection simply fitting with each other. Furthermore, by providing an inner peripheral surface cleaning step after the final step of manufacturing a small-diameter metal tube, all foreign substances that have entered or adhered during the manufacturing process have been removed, and foreign substances that have entered and adhered to the inside have been reduced to metal powder. In the case of (1), a small-diameter metal pipe whose inner peripheral surface is cleaned is incorporated in the path for supplying fuel from the injection pump to the engine, which is dissolved by the chemical polishing liquid, so that the engine malfunctions due to foreign matter. Never.

A chemical polishing liquid flowing by suction into the inside of the above-mentioned small-diameter metal tube is brought into contact with the inner peripheral surface to be cleaned together with the chemical polishing, and when the foreign matter that has entered and adhered to the inside is metal powder, the chemical polishing is performed. In carrying out the treatment method of dissolving with a liquid, the chemical polishing liquid injection tank 1 as shown in FIG. A supply tank 3 for storing the chemical polishing liquid 2 which is pressurized and filtered by the filter F, and which is connected to the supply tank 3 via a hose 23 and which can move up and down relatively with respect to the supply tank 3 by a handle H; Vessel 3a
And a cleaning table 4, a storage tank 5, a protection tank 6, and a vacuum pump 7 are used. In the inner peripheral surface cleaning device 17, the end of the supply tube 8 extending from the measuring device 3 a is detachably attached to one end 10 of the small-diameter metal tube 9 placed on the washing table 4. A supply unit 11 fitted and connected is detachably fitted to and connected to the other end 13 of the small-diameter metal tube 9 at an end of a suction tube 12 extending from the storage tank 5. One end 10 and the other end 1 of the small-diameter metal tube 9 are provided respectively.
When the supply unit 11 and the suction unit 14 were respectively fitted and connected to 3, the storage tank 5 and the protection tank 6, and the pipes 15 respectively provided between the protection tank 6 and the vacuum pump 7 were included. The suction cleaning circuit 16 is formed.

Further, in the inner peripheral surface cleaning device 17, the bottom 1 of each of the supply tank 3, the storage tank 5 and the protection tank 6 is provided.
8, a fluid outlet 19 is provided.
It is preferable that an on-off valve 21 is provided in the piping section 20 connected to the pipe. By operating these opening / closing valves 21, the chemical polishing liquid 2 is temporarily stored in the storage tank 24, the valve pump P is driven as necessary, and the chemical polishing liquid 2 is filtered by the filter F and supplied to the supply tank 3.
And the chemical polishing liquid 2 can be used repeatedly, and the chemical polishing liquid 2 with reduced polishing performance can be discharged out of the system.

Further, the supply tube 8 extending from the measuring device 3a and the suction tube 1 extending from the storage tank 5
2 is a branch arrangement in which a plurality of supply tubes 8 and suction tubes 12 are arranged in parallel, so that the inner peripheral surface cleaning of a plurality of small-diameter metal tubes 9 can be simultaneously performed in parallel. It becomes possible and the working efficiency is improved, which is more preferable.

In addition, the handle H is operated to adjust the amount of the chemical polishing liquid 2 introduced into the measuring device 3a in accordance with the size of the small-diameter metal tube 9 to be chemically polished, such as the diameter and length, and the cleanliness. Adjust,
When the vacuum pump 7 is operated after closing the on-off valve 25,
Since chemical polishing is performed by the amount of the chemical polishing liquid 2 introduced into the measuring device 3a, optimal cleaning can be obtained, and the possibility that the storage tank 24 overflows can be eliminated.

When cleaning the inner peripheral surface of the small-diameter metal tube 9 by the inner peripheral surface cleaning device 17, the supply of the small-diameter metal tube 9 is performed at the supply section 11 provided at the end of the supply tube 8. The one end 10 is fitted and connected, and the suction part 14 provided at the end of the suction tube 12 is connected to the other end 13 of the small-diameter metal tube 9.
After the suction cleaning circuit 16 is formed, the vacuum pump 7 connected to the protection tank 6 is operated, and the chemical polishing liquid 2 is caused to flow inside the small-diameter metal tube 9 by a vacuum suction operation. 1 inside the suction cleaning circuit by the flowing chemical polishing liquid 2
In order to efficiently polish, wash and clean the inner peripheral surface of the small-diameter metal tube 9 arranged in the tube 6, the inner peripheral surface of the small-diameter metal tube 9 is improved in cleaning degree, and the outer periphery due to the leakage of the processing liquid is increased. It is possible to easily manufacture a highly durable small-diameter metal tube in which the plating film on the surface is not peeled off.

Although the above embodiment has been described with reference to an example in which a chemical polishing liquid is used, the present invention can also be used for various applications such as flushing and alkali cleaning. Furthermore, in the above-described embodiment, a thick-walled thin metal pipe used for a fuel injection pipe for a diesel engine, a hydraulic pipe for an automobile, and the like which require extremely strict cleanliness has been described. It can also be used for cleaning the inner peripheral surface of metal tubes.

[0023]

The present invention provides a method for cleaning the inner peripheral surface of a small-diameter metal tube, particularly in a process of manufacturing a thick-walled small-diameter metal tube used for a fuel injection tube for a diesel engine, a hydraulic pipe for an automobile, or the like. As a treatment method to keep the degree high, in the final step, the chemical polishing liquid flowing by suction action is brought into contact with the inner peripheral surface of the small-diameter metal tube to efficiently clean the inner peripheral surface of the small-diameter metal tube. The cleanliness of the inner peripheral surface is high,
In addition, the connection between the small-diameter metal tube, the supply tube and the suction tube can be easily performed without using a special mounting jig, there is no peeling of the plating film on the outer peripheral surface due to leakage of the processing solution, and the oil according to the conventional technology is used. Since the high-pressure washing step and the like can be omitted, it is possible to easily manufacture a small-diameter metal tube capable of reducing the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a schematic front view of an apparatus according to an embodiment of the present invention.

[Description of Signs] 1 Chemical polishing liquid injection tank 2 Chemical polishing liquid 3 Supply tank 3a Meter 4 Washing table 5 Storage tank 6 Protection tank 7 Vacuum pump 8 Supply tube 9 Small diameter metal tube 10 One end 11 Supply unit 12 Suction tube 13 Other end 14 Suction unit 15 Pipe line 16 Suction / cleaning circuit 17 Inner peripheral surface cleaning device 18 Bottom part 19 Fluid discharge port 20 Pipe unit 21 Open / close valve 22 Open / close valve 23 Hose 24 Storage tank P Pump F Filter H handle

Claims (4)

[Claims] 1. A thin metal pipe for a small diameter metal pipe is subjected to a surface treatment step, a head forming step of a connection end, and a bending step of forming the entire pipe into a pipe shape, and then the bent thin pipe is processed. The two ends of the diameter metal pipe are fitted and connected to a supply section and a suction section of an inner peripheral surface cleaning device for the metal pipe, respectively, to form a suction cleaning circuit, and a chemical polishing liquid existing in the suction cleaning circuit. By a high-pressure suction operation, and polishing and cleaning the inner peripheral surface of the small-diameter metal tube disposed in the suction-cleaning circuit with the chemical polishing liquid. Cleaning method. 2. An apparatus configured by sequentially connecting a supply tank for storing a chemical polishing liquid, a storage tank, a protection tank, and a vacuum pump, the end of a supply tube extending from the supply tank. A supply section detachably fitted to and connected to one end of the small-diameter metal tube; and a detachably detachably connected to the other end of the small-diameter metal tube at an end of a suction tube extending from the storage tank. Suction units that are fitted and connected are provided, respectively, and the supply unit and the suction unit are fitted to one end and the other end of the metal tube, respectively,
An apparatus for cleaning the inner peripheral surface of a small-diameter metal pipe, wherein a suction cleaning circuit including a pipe disposed between the storage tank and the protection tank and between the protection tank and the vacuum pump is formed. 3. The supply tank is provided with a measuring device capable of moving up and down with respect to the supply tank, and a predetermined amount of the chemical polishing liquid introduced into the measuring device is sucked by the vacuum pump to reduce the diameter of the fine polishing liquid. The inner peripheral surface of the metal tube is caused to flow.
An apparatus for cleaning an inner peripheral surface of a small-diameter metal pipe according to the above. 4. A fluid discharge port is provided at a bottom of each of the supply tank, the storage tank, and the protection tank, and an on-off valve is provided at a pipe connected to the fluid discharge port. The apparatus for cleaning the inner peripheral surface of a small-diameter metal tube according to claim 2 or 3.