RU2015854C1 - Apparatus for powder materials cover application on inner surfaces of lengthened pipes - Google Patents

Abstract

FIELD: mechanical engineering. SUBSTANCE: apparatus for cover application on inner surfaces of pipes has rod 1 with left 2 and right 3 lids rigidly fixed on it. Pattern mandrel 4 is located between the lids and compensating spring 5 is mounted inside the mandrel. Processed pipe 15 is placed in stationary supports 21 and connected to the drive of rotation by an intermediate link fixing on it. Then the following pieces are mounted on rod 1: a capacity with adhesive stuff, guide 9 with fixed to it pullings 10, connected through mechanism 13 to tank 12 hose 11 to feed adhesive stuff, baffle 14 is fixed on opposite to hose 11 side. To exercise process of cover application they switch on mechanism 13 for adhesive stuff forced feeding. Adhesive stuff, that is forced into the inner cavity of rod 1 , through radial holes in the rod fill inner capacity of mandrel 4 and through holes in it, using pores in cover 7 goes to outer surface of the cover. Then powder feeding mechanism 19 is switched on. As powder achieves a groove in rod 1 the mechanism of the rod movement along the pipe and the mechanism of the pipe rotation are switched on. During the whole process apparatus provides uniform application of adhesive stuff layer and a powder layer over it. Apparatus provides for reduction of applied cover by roller 26 and cutter 24. EFFECT: apparatus is used for powder cover applications on inner surfaces of lengthened pipes. 3 cl, 5 dwg

Description

 The invention relates to powder metallurgy, in particular to a device for coating metal powder on the inner surface of products.

 A device for applying coatings of metal powders, including an electromagnet with a core, made in the form of a disk, a current source and a drive, and the electromagnet is installed inside the product [1].

 However, such a device is only suitable for coating of ferromagnetic powders.

 A device for coating of metal powders is also known, comprising a powder container and a drive. In this case, the container and the product to be coated are mounted on the drive, and the device assembly is placed inside the high-frequency inductor [2].

 This device does not allow coating on the inner surface of long products, due to the limited size of the powder container and its stationary placement relative to the product.

 It is known "A device for coating powders on the inner surface of products containing a heating unit, a clamping device, a rotation unit with a drive. However, this device, due to its relatively large dimensions, is unsuitable for applying internal coatings to long pipe of small diameter.

 The known device describes the mechanism of forced movement of the powder along the pipe due to the force interaction between the screw and the transported powder. Moreover, it provides for the presence of a screw from the beginning of the pipe to the place where the powder is transported, i.e. along the entire pipe. Such a device, providing the transport of powder, cannot solve the problem of applying the layer due to the absence of conditions for fixing the powder on the inner surface of the pipe. In addition, the need to match the dimensions of the screw to the dimensions of the pipe, i.e. long length with a small diameter, inevitably leads to significant, and, as a rule, insurmountable difficulties in creating the necessary rigidity of the screw. Due to possible deflections, a non-rigid screw cannot ensure the application of an equal-thickness, defect-free, continuous layer on the inner surface of the pipe.

 The closest to the proposed invention in terms of technical nature and the achieved result is a device for applying coatings of metal powders, selected as a prototype, containing a container for powder, a container for adhesive, the shell of which are the walls of the pipe being processed, and a translational drive with traction.

 This device has the following disadvantages.

 Firstly, with the non-vertical orientation of the processed pipe, there is no guarantee of 100% filling of the chamber volume formed by the pipe itself and the covers (plug and cork) with adhesive and, therefore, the guarantee of continuous application of the latter on the entire surface to be treated, which leads to the appearance of discontinuities in the applied layer.

 Secondly, if the pulling force and wear of the rubbing surface of the movable cover are exceeded, it is possible for the adhesive to flow from the container to the already applied layer, which will lead to the washing off of the powder from this layer and the destruction of the latter.

 Thirdly, due to the lack of guaranteed centering of the moving cover relative to the pipe, distortions of this cover relative to the axis of the pipe are possible, which will lead to unequal thickness of the applied adhesive layer, and as a result of the coating itself.

 Fourth, the presence of friction between the treated surface of the pipe and the powder in the hopper moving along the pipe inevitably causes one or a group of particles to slip along the processed surface. Such slip determines defects in the applied layer in the form of scratches, powder-coated areas and other types of discontinuities.

 All of these shortcomings are greatly enhanced by the non-vertical orientation of the processed pipe, and with a sufficiently large length of this pipe make the device under consideration unsuitable for implementation.

 These disadvantages of the prototype boil down to the impossibility of obtaining a high-quality, equal-thickness inner coating over the entire surface of vertically oriented long pipes.

 The present invention is aimed at providing the possibility of applying to the inner surface of long pipes of small diameter a high-quality, uniform thickness coating for any orientation of these pipes by autonomously making an adhesive container by tightly fixing both of its covers with a perforated rigid shell interposed between them, lined with a soft elastic shell with capillary -porous structure throughout the volume on a hollow rod with a partition in its inner cavity dividing this floor perpendicular to the axis of the rod, and in the zone of the powder supply directly behind the partition in the lower part of the through groove, behind which is attached to the rod connected to the forced powder supply mechanism and passing through the reinforced at the end of the pipe, a centering sleeve, a groove having in the upper part along a section forming along the entire length into which an expander is buried in front of the pipe to be machined, forming an opening in this groove To feed the powder into it.

 Centering of the rod with containers along the pipe surface to be machined is carried out by a guide located on this rod from the side of the adhesive container coaxially with the pipe. The pipe itself is kinematically connected with the mechanism that tells it to rotate.

 A comparative analysis of the proposed solution with the prototype shows that the claimed device differs from the prototype in the design of the container for the adhesive, ensuring its autonomy and the possibility of forcing the adhesive into the application zone and consisting of a rod, covers, shell with a shell described above, as well as the design containers for powder located in the inner cavity of the rod, the presence of a tubular, flexible elastic gutter connected to this container for transporting powder to for powder having a through section in the upper part along the generatrix along the entire length of this trough and an expander buried inside it, forming an opening for loading the powder into the trough.

 Thus, the claimed "Device for coating the inner surface of long pipes" meets the criterion of "novelty."

 Comparison of the proposed solution with the prototype and other technical solutions showed that the mechanisms of forced supply of powder and adhesive and the progressive movement of the chamber along the pipe and the rotation of the pipe itself, as well as their use in devices for applying layers of powder on the pipe surface, are known.

 However, the same comparison of the proposed solution with the prototype and other technical solutions in the art did not allow them to identify signs that distinguish the claimed solution from the prototype, which allows us to conclude that the criterion of "inventive step".

 Metal pipes with an internal coating of metal powders deposited using this device compared to the same pipes without coatings are characterized by 2-4 times higher heat transfer and heat transfer coefficients, the ability to work without burns at high heat fluxes, a more uniform distribution of heat load over pipe surfaces, etc., which dramatically increases the efficiency of the heat exchange processes in which they are used.

 Existing devices for applying internal coatings are either generally not applicable for pipes with a small diameter of the holes, or do not create a capillary-porous structure throughout the volume of the coating that provides the above advantages. Therefore, the device in question is effectively used, for example, for applying internal porous coatings on the surfaces of pipes that are part of various heat exchange equipment.

 Thus, the present invention also meets the criterion of "industrial applicability".

 Figure 1 shows a longitudinal section of a device for coating of powder materials on the inner surface of long pipes; figure 2 - capacity for adhesive, section; figure 3 - hole in the gutter formed by the expander to load the applied powder material into the gutter; figure 4 is a section of a machining site of the applied coating; figure 5 is a section of a container for adhesive with a single load.

 The device consists (Fig. 1) of a container for an adhesive substance, a section of which is shown in Fig. 2, including a rod 1 with left caps 2 and 3 right rigidly fixed on it, between which a perforated shell 4 is located, with a compensating shell inside spring 5, which stabilizes the pressure of the adhesive in the container, and a movable bottom 6. On the outside, this container is limited by a soft elastic shell with a capillary-porous structure 7, mounted on the lids 2 and 3. The rod 1 is divided by a partition 8 into the right and left hours and. The right part refers to the container for the adhesive and serves to fill this container with the adhesive itself. The left part of the rod 1 is a container for applied powder material. On the rod 1 (Fig. 1), a guide 9 is located to the right of the adhesive container, to which rods 10 are attached, connected to the drive (not shown) of the rod moving along the pipe, and a hose 11 is attached to the rod on the same side, along which the adhesive itself enters the adhesive container from the tank 12 by the force feed mechanism 13.

 The left part of the rod, which is a container for the applied powder material, is connected to the groove 14, which enters the inside of the processed pipe 15 through the centering sleeve 16 and has along the entire length along the generatrix a cut into which, before entering the processed pipe 15, an expander 17 is formed, forming in the groove 14 hole (Fig. 3) for the entrance of the feeder 18, connected through the mechanism 19 of the forced supply of powder with the hopper 20. The processed pipe 15 itself is mounted in the supports 21 and connected through an intermediate link 22 to the mechanism, I inform it s rotation (not shown).

 The described device may include a coating machining unit (Fig. 4), consisting of a holder 23 rigidly mounted on the rod 1, in which the cutter 24 and the sealing roller 26 located on the axis 25 are mounted.

 The device operates as follows.

 The pipe 15 to be machined is installed in the fixed supports 21 and connected to the rotation drive by fixing the intermediate link 22. Then, in accordance with FIG. 2, an adhesive container is mounted on the rod 1, the guide 9 with the rods 10 attached to it, the hose 11 for the supply of adhesive, already connected through the mechanism 13 to the tank 12, and from the side opposite from the hose 11 fix the groove 14. Next, the free end of the groove 14 is introduced from the end of the coating process into the pipe 15 and move it along the entire t the tubes 15 through the centering sleeve 16 up to the location of the adhesive container (or the coating machining unit, if used) at the opposite end of the pipe 15. Connect the chute 14 to the powder supply mechanism 19.

 After carrying out the described operations, the device is ready for operation. To carry out the application process include a mechanism 13 for the forced supply of adhesive. After some time (previously determined experimentally by the state of the outer surface of the outer shell 7 visually advanced), the adhesive substance pumped by the mechanism 13 from the tank 12 through the hose 11 into the inner cavity of the rod 1 fills the inner volume of the shell 4 through the holes in it and through the holes in it through the pores in the shell 7 passes to the outer surface of this shell. After that, the powder supply mechanism 19 is turned on, and when the powder reaches the groove in the rod 1 (determined by the spilling of the powder from the groove), the rod 1 is moved along the pipe and the latter rotates. The coating process itself began.

 The adhesive during coating during the translational movement of the rod 1 with the container for adhesive along the pipe 15 to be transferred is transferred from the outer surface of the sheath 7 to the inner surface of the pipe 15 and immediately thereafter in accordance with the construction from the groove in the rod 1 to the applied adhesive the powder forcibly transported to the groove wakes up, which is fixed there by gluing. The rotation of the pipe 15 and the translational movement of the rod 1 ensures uniform application of a layer of adhesive and a layer of powder on it throughout the process.

 Further, in the case of using the coating machining unit, the sealing roller 26 is moved to the already applied coating and the cutting edge of the cutter 24 is left behind. As a result of combining the rotational movement of the pipe 15 and the translational motion of the roller 26 and the cutter 24, the layer is first compressed and then the specified profile is cut over the entire surface of the applied coating.

 The powder is transported from the hopper 20 to the groove in the rod 1 in accordance with FIG. 1 by loading it into the groove 14 through an opening formed in the groove by the expander 17. The expander 17 is recessed into the cut of the groove 14 and due to its configuration (section BB in FIG. .3) when the chute 14 is moved forward progressively behind the rod 1, it opens it according to the section therein, as a result of which an opening is formed in which the feeder 18 is connected, connected to the powder feeding mechanism into the chute 19 and further moving it of the chute to the place of the coating.

 Other options are possible. For example, powder is filled by gravity into the indicated hole from the hopper, and the working element (screw, wheel with blades, piston, etc.) of the powder supply mechanism, already located at the place of formation of this hole, moves the powder along the groove 14 to the groove in the rod 1 , i.e. to the coating site. Behind the expander due to its elasticity and sleeve 16, the chute closes.

 It is rational to load powder into the gutter in the immediate vicinity of the pipe being processed, then the remaining unused part of the gutter, due to its flexibility, can be placed in any unoccupied place and not necessarily in a straight line, in order to save space. The same applies to the hose 11 with an adhesive. The gutter and hose may be soft or rigid pipe. In the latter case, the download is made from the free end.

 After coating along the entire length of the pipe, all mechanisms are turned off, the chute with the rod is removed from the pipe.

 The treated pipe is disconnected from the rotation drive, removed from the supports and subjected to heat treatment, as a result of which the adhesive burns out, and the powder is baked to the pipe.

 As can be seen from the above, the device provides coating for any orientation of the pipe. The design of the container for the adhesive eliminates the possibility of leakage of the adhesive from it onto the already applied layer. When applying the powder itself, there are no factors causing mechanical damage to the coating.

 When using the machining unit of the applied coating to eliminate the possibility of damage to the latter during compaction due to the sliding of the sealing roller 26 and ensuring only the rolling of the latter along the layer, the axis 25 of the roller 26 is perpendicular to the helical line along which the roller moves relative to the inner surface of the pipe.

 To ensure compaction of the entire applied layer of powder, the length of the roller should be greater than the length of the groove in the rod 1.

 The profile formed on the applied layer by the cutter 24 is determined by the sharpening of the cutting edge of the latter and can be selected in accordance with the requirements. To increase the resulting free surface and the technological simplification of applying a complex profile, it is possible to install two or more cutters in the holder 23 at the same time.

, где v - скорость перемещения стержня 1, n - скорость вращения трубы 15. Варьируя величинами L, v, n, можно наносить как сплошной слой, так и в форме винтовой линии.The length L of the through groove in the rod 1 for supplying powder to the place of the applied coating for applying a continuous layer should be not less than the pitch of the helix relative to the movement of the groove along the pipe surface, i.e. L>

where v is the speed of movement of the rod 1, n is the speed of rotation of the pipe 15. By varying the values of L, v, n, you can apply both a continuous layer and in the form of a helix.

 The rate of fixation of the applied powder on the pipe surface can be changed either by varying the composition of the adhesive that determines the adhesive properties of the latter, or by heating the pipe in the required places with known methods and known devices, for example, by placing it inside the high-frequency apparatus inductor, which may be required when using a machining unit applied coating.

 If in the device under consideration the adhesive container contains the entire amount of adhesive required for applying the porous coating, then it does not need to be constantly fed with adhesive and, therefore, there is no need to use a hose 11, a mechanism 13 and a tank 12.

 In this case (Fig. 5), the rod 1 on the side of the adhesive container is provided with a threaded plug 27, and on the movable bottom 6, the rods 28 are rigidly fixed perpendicular to it, passing through the holes in the cover 2 and having the ability to move axially in these holes. The free ends of these rods are equipped with a device, for example, a thread on the rod - nut 29, capable of fixing the position of the movable bottom 6 in the extreme right position with a maximum compressed spring 5.

 The adhesive is poured into the container through the hole in the rod 1 from the side of the screw plug 27, while the spring 5 is compressed, the movable bottom 6 is fixed in the position as close as possible to the cover 3.

 After filling the container with adhesive, the plug 27 is screwed, the rods 28 are released from the locking device, for example, by screwing the nuts 29 from the rods 28, as a result of which the spring 5 is able to freely act on the movable bottom 6.

 The application of adhesive to the inner surface of the pipe is carried out according to the scheme described above.

 As the adhesive in the tank decreases, the movable bottom 6 under the action of the spring 5 constantly compresses the adhesive remaining in the tank, ensuring its continuity along the inner, and therefore due to the porous structure and outer surfaces of the shell 7.

 The described device was tested, used and gave positive results in the manufacture of an experimental batch of heat transfer tubes with a diameter of 14 mm and a length of 2 m

Claims (3)

 1. DEVICE FOR APPLICATION OF COATINGS FROM POWDER MATERIALS ON INTERNAL SURFACES OF LONG-LINE PIPES, containing nodes for supplying powder and adhesive and drives, characterized in that it is equipped with an elastic groove installed with the possibility of its entry into the pipe being processed through the centering tube , and a hose for supplying adhesive, and the node for supplying powder and adhesive is made in the form of a hollow rod, the cavity of which is divided by a rigidly fixed partition into the left zone for powder about a through groove in the lower part of the rod for spilling powder onto the pipe surface and to the right zone for supplying adhesive with radial through holes in the rod connecting its cavity to the container for adhesive, the latter being formed by left and right covers fixed on the rod, between which fixed a rigid perforated shell lined with a soft elastic shell with a capillary-porous structure and with a movable bottom placed inside it with a compensating spring, and directly venno behind the right cover to the hose for the adhesive on the rod guide sleeve is installed.  2. The device according to claim 1, characterized in that in the upper part of the elastic groove along the entire length, a through cut is made to accommodate the expander.  3. The device according to claim 1, characterized in that it is equipped with a machining unit of the applied coating, made in the form of a holder mounted on a rod supporting a cutter and located on the axis of the sealing roller.

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