A painting equipment and painting process for oil casing surfaces

Abstract

This invention relates to the field of spray painting equipment technology, specifically disclosing a spray painting device and process for the surface of oil casing. The device includes: a mixing chamber; a storage tank located below the mixing chamber; a sliding plate located above the storage tank; the sliding plate slides up and down to change the volume of the mixing chamber; a filter screen located at the lower end of a feeding pipe; a connecting pipe that slides up and down through the feeding pipe; an opening on the side of the connecting pipe; a cleaning pipe located on the storage tank; and an adjusting component that moves the sliding plate up and down along the mixing chamber when the sliding plate is at its lowest point. A limiting component is located on the inner wall of the mixing chamber, applying resistance to the upward movement of the sliding plate. In this oil casing spray painting device and process, the sliding plate allows the paint in the mixing chamber to flow back into the storage tank, reducing paint residue in the mixing chamber. Simultaneously, the cleaning pipe backwashes the filter screen, preventing clumping and accumulation, and also agitates the paint to prevent stratification caused by stagnation.

Description

Technical Field

[0001] This invention relates to the field of spray painting equipment technology, specifically to a spray painting equipment and process for oil casing surfaces. Background Technology

[0002] During the use of existing spray painting equipment, paint is prone to sedimentation and stratification during storage, affecting the uniformity of spraying. Furthermore, impurities or particles in the paint can easily clog the nozzles and reduce the coating quality. Although some companies have tried electrophoretic coating technology, traditional electrophoretic coatings require high-temperature curing (above 150°C) and contain heavy metal components, making it difficult to meet environmental protection standards and low-temperature curing requirements.

[0003] Oil casing and tubing are essential equipment in oil drilling, primarily used to support the wellbore during and after drilling to ensure the smooth operation of the well and its subsequent normal functioning. Operating under high temperature, high pressure, and corrosive media (such as H2S and CO2), the quality of the anti-corrosion coating on the casing and tubing directly affects the well's lifespan and safety. Traditionally, painting the casing and tubing surface is done manually or with semi-automatic spray guns. However, prolonged use in high temperature, humidity, and corrosive media can easily lead to rust, resulting in decreased structural strength and even perforation and leakage.

[0004] Chinese patent application CN114042554A discloses a siphon-type paint spray gun, comprising: a spray gun body with an inlet; a paint storage tank with an outlet; and a connecting pipe with its two ends connected to the inlet and outlet respectively. The connecting pipe has an accumulation section for accumulating paint, and the accumulation section is equipped with a stirring structure that can stir the paint located in the accumulation section under the drive of the paint being drawn into the spray gun body. The stirring structure can improve the uniformity of the paint before it enters the spray gun body, thus improving the spraying effect, especially by stirring up any unmixed paint accumulated in the guide pipe.

[0005] In related technologies, when spraying oil casing, brief stops are required to adjust the spraying position or replace fittings. Furthermore, when the coating is thick, it may not solidify quickly enough, necessitating a pause in spraying. During these pauses, the paint inside the spray gun dries and hardens, and sediment forms in the storage tank. Agglomerated material accumulates on the underside of the filter screen inside the feed pipe. When spraying resumes after a period of pause, the paint sediment, buildup on the filter screen, and caking on the inner wall of the spray gun lead to a decline in paint quality, preventing normal spraying. Summary of the Invention

[0006] This invention provides a painting equipment and process for oil casing surfaces, aiming to solve the problems in related technologies where paint in the spray gun dries and hardens when painting is paused, and paint in the storage tank settles. Additionally, clumps of material accumulate on the lower side of the filter screen in the feed pipe. When painting resumes after a period of pause, the paint sedimentation, accumulation at the filter screen, and caking on the inner wall of the spray gun lead to a decline in painting quality, preventing normal painting.

[0007] A spray painting device for the surface of an oil casing includes: a handle, a nozzle, and a storage tank, and further includes: a mixing chamber, a feeding pipe, a cleaning pipe, an adjusting component, and a limiting component; the mixing chamber is vertically arranged on the right side of the nozzle, the storage tank is arranged below the mixing chamber, and a sliding plate that slides up and down is arranged on the upper side of the storage tank. The sliding plate slides up and down to change the volume of the mixing chamber. The feeding pipe is arranged inside the storage tank, and its lower end abuts against the bottom of the storage tank. A filter screen is arranged at the lower end of the feeding pipe. A connecting pipe that slides up and down is passed through the feeding pipe. The upper end of the connecting pipe is connected to the lower end face of the sliding plate. An opening is arranged on the side of the connecting pipe. The cleaning pipe is arranged on the storage tank. When the sliding plate is at its lowest point, the cleaning pipe is directly opposite the opening. An air inlet pipe is arranged on the storage tank to pump gas into the storage tank.

[0008] The adjusting component moves the sliding plate up and down along the mixing chamber, and the limiting component is set on the inner wall of the mixing chamber, which applies resistance to the upward movement of the sliding plate.

[0009] Its effects are as follows: By setting up a sliding plate, adjusting components, and limiting components, when spraying is paused, the sliding plate moves down to the lowest position, the mixing chamber volume is reduced to its minimum, and the residual paint is forced back into the storage tank, reducing the risk of drying and caking. The cleaning pipe and the connecting pipe opening are aligned, and when reused, gas enters the connecting pipe through the cleaning pipe, backwashing the clumps accumulated on the underside of the filter screen from above. The air inlet pipe continuously pumps air to make the paint in the storage tank flow, preventing sedimentation and stratification. The sliding plate actively adjusts the mixing chamber volume to reduce the amount of residual paint in the mixing chamber. The cleaning pipe backwashes the filter screen to solve the problem of clumping and accumulation. The air inlet pipe continuously agitates the paint to prevent stratification when it is left to stand. This achieves multi-dimensional anti-clogging and anti-sedimentation when the spraying is paused and reused, effectively solving the problem of paint sedimentation, accumulation at the filter screen, and caking on the inner wall of the spray gun, which can lead to a decline in spraying quality.

[0010] Preferably, the storage tank is equipped with a vertical locking block that slides vertically. An elastic element is provided between the locking block and the storage tank. When the sliding plate is at its lowest position, the locking block extends into the air inlet pipe, blocking the connection between the storage tank and the outside world through the air inlet pipe. The effect is that when the locking block is not in use, the sliding plate moves down to its lowest position, and the sliding plate pushes the locking block to overcome the resistance of the elastic element and insert it into the air inlet pipe, forming a physical blockage. At this time, the gas in the air inlet pipe cannot enter the storage tank, ensuring that when painting resumes, the gas enters the storage tank through the feed pipe to fully mix the paint in the storage tank.

[0011] Preferably, the adjustment component includes a pressure rod and a connecting plate. The pressure rod is vertically mounted on the handle and slides up and down along the mixing chamber. The lower end of the pressure rod is provided with a connecting plate, and a snap-fit ​​structure is provided between the connecting plate and the sliding plate. When snap-fitted, the connecting plate and the sliding plate move up and down synchronously.

[0012] Preferably, the lower half of the feed pipe is a flexible pipe, which can be bent. The lower end of the feed pipe abuts against the bottom surface of the storage tank. The effect is to solve the problem of flow blockage caused by material accumulation under the filter screen, and at the same time, to make the feed pipe adaptable to storage tanks of different sizes, ensuring that the sediment is effectively stirred and mixed when the paint is reused, and avoiding the decline in spraying quality caused by sedimentation after the paint spraying is interrupted.

[0013] Preferably, the lower end face of the sliding plate is conical, and the upper end face of the storage tank is provided with a groove that matches the lower end face of the sliding plate.

[0014] Preferably, a flexible ring is provided on the side of the sliding plate that abuts against the side wall of the mixing chamber. The effect of this is that the flexible ring effectively fills the gap between the edge of the sliding plate and the inner wall of the mixing chamber, thus avoiding the problem of incomplete paint cleaning inside the mixing chamber.

[0015] Preferably, the limiting component includes a spring block and a slot, the spring block is telescopically disposed on the side wall of the groove, the spring block telescopically extends and retracts along the radial direction of the mixing chamber, and the slot is annularly disposed on the side wall of the connecting plate.

[0016] Preferably, the storage tank includes a sealing cover and a tank body. The sealing cover is snapped onto the bottom end of the mixing chamber. The cleaning pipe and the air inlet pipe are disposed inside the sealing cover. The upper end of the feeding pipe is connected to the lower end of the sealing cover. The tank body is disposed on the lower side of the sealing cover. A limiting component is provided between the feeding pipe and the connecting pipe to restrict the relative rotation between the feeding pipe and the connecting pipe.

[0017] Preferably, the opening at the lower end of the feeding pipe is outwardly flared, and the filter screen is set at the lower opening of the feeding pipe. The effect is that by setting it in an open shape, the filtration area of ​​the filter screen is increased, preventing the filter screen from being clogged due to paint sedimentation, and ensuring the continuity of paint delivery.

[0018] A process for painting the surface of an oil casing, using any of the oil casing surface painting equipment described in any one of the claims, the process includes the following steps:

[0019] S1. When the painting operation of the oil casing needs to be paused, the sliding plate is driven to move down to the bottom of the mixing chamber by adjusting the component. The sliding plate compresses the space of the mixing chamber and pushes the residual paint in the mixing chamber back into the storage tank. At the same time, the downward movement of the sliding plate drives the connecting pipe to move down, so that the opening on the connecting pipe is aligned and connected with the cleaning pipe.

[0020] S2. Before restarting the painting process, gas is introduced into the connecting pipe through the cleaning pipe. The gas is blown out in the opposite direction downward through the feeding pipe to backwash the filter screen at the bottom of the feeding pipe and remove the clumps on the filter screen. At the same time, the gas enters the bottom of the storage tank and rises upward to stir and mix the paint in the storage tank and eliminate paint separation.

[0021] S3. After the paint is mixed evenly, the sliding plate is driven to move upward and reset by adjusting the component. The opening of the connecting pipe is disconnected from the cleaning pipe, the air inlet pipe resumes ventilation, and the paint enters the mixing chamber through the feeding pipe and connecting pipe under air pressure. The paint is then sprayed onto the surface of the oil casing through the nozzle.

[0022] Its effects are as follows: By setting up a sliding plate, adjusting components, and limiting components, when spraying is paused, the sliding plate moves down to the lowest position, the mixing chamber volume is reduced to the minimum, and the residual paint is pressed back into the storage tank, reducing the risk of drying and hardening. The cleaning pipe and the connecting pipe opening are aligned, and when reused, gas enters the connecting pipe through the cleaning pipe and flushes the clumps accumulated on the bottom side of the filter screen from below. The air inlet pipe continuously pumps air to make the paint in the storage tank flow, preventing sedimentation and stratification. The sliding plate actively adjusts the mixing chamber volume to reduce the amount of residual paint in the mixing chamber. The cleaning pipe backwashes the filter screen to solve the problem of clumping and accumulation. The air inlet pipe continuously agitates the paint to prevent stratification caused by stagnation. This achieves multi-dimensional anti-clogging and anti-sedimentation when the spraying is paused and reused, effectively solving the problem of paint sedimentation, accumulation at the filter screen, and caking on the inner wall of the spray gun, which can lead to a decrease in spraying quality. It is especially suitable for spraying workpieces such as oil jackets and pipes, which have extremely high requirements for the continuity and uniformity of the anti-corrosion coating.

[0023] By adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0024] The painting device and its adjusting components, sliding plate, limiting components and storage tank provided by the present invention, through the sliding plate set in the mixing chamber, make the volume of the mixing chamber adjustable, and collect the remaining paint in the mixing chamber into the storage tank. The sliding plate, together with the liftable connecting pipe, uses the cleaning pipe to rinse the filter area at the beginning of the spraying, and at the same time, the gas discharged from the lower end of the feeding pipe makes the paint in the storage tank flow effectively, preventing paint sedimentation and stratification and filter clogging, which has the advantages of improving the spraying quality and equipment reliability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the painting device of the present invention.

[0026] Figure 2 This is a cross-sectional schematic diagram of the mixing chamber of the present invention.

[0027] Figure 3 This is a cross-sectional structural diagram of the storage tank of the present invention.

[0028] Figure 4 for Figure 3 An enlarged schematic diagram of part A in the middle.

[0029] Figure 5 This is a schematic diagram of the structure of the sliding plate of the present invention.

[0030] Figure 6 This is a schematic diagram of the feeding pipe of the present invention.

[0031] Figure 7 This is a schematic diagram of the limiting component of the present invention.

[0032] Figure 8 for Figure 7 Enlarged diagram of part B.

[0033] Figure label:

[0034] 11. Handle; 12. Nozzle; 2. Mixing chamber; 3. Sliding plate; 4. Storage tank; 41. Feed pipe; 42. Filter screen; 43. Connecting pipe; 44. Sealing cap; 441. Cleaning pipe; 442. Air inlet pipe; 443. Groove; 45. Tank body; 5. Adjustment component; 51. Pressure rod; 52. Connecting plate; 6. Limiting component; 61. Spring block; 62. Slot; 71. Locking block; 72. Elastic element. Detailed Implementation

[0035] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0036] When the spray painting equipment is paused, it is usually hung up using the hook on the handle 11. During pauses, the paint in the storage tank 4 is prone to sedimentation and stratification, and clumps of material accumulate below the filter screen 42. The residual paint in the mixing chamber 2 comes into contact with air and dries, obstructing paint flow and reducing spray quality after restarting. Traditional methods use a stirring structure to delay sedimentation, but they cannot actively clean the filter screen 42 when spraying begins and cannot reduce the exposed area of ​​residual paint in the mixing chamber 2, posing a risk of drying.

[0037] like Figures 1 to 8As shown, a spray painting device for the surface of an oil casing includes: a mixing chamber 2, a feeding pipe 41, a cleaning pipe 441, an adjusting component 5, and a limiting component 6. The mixing chamber 2 is vertically arranged to the right of the spray nozzle 12. A storage tank 4 is arranged below the mixing chamber 2. A sliding plate 3 that slides up and down is arranged on the upper side of the storage tank 4 to change the volume of the mixing chamber 2. The lower end of the feeding pipe 41 abuts against the bottom of the storage tank 4 and is provided with a filter screen 42. A connecting pipe 43 passes through the inside of the feeding pipe 41. The upper end of the connecting pipe 43 is connected to the sliding plate 3 and has an opening on its side. When the cleaning pipe 441 is aligned with the opening, it performs backflushing. The adjusting component 5 drives the sliding plate 3 to move. The limiting component 6 applies resistance to the upward movement of the sliding plate 3 so that the sliding plate 3 does not move upward during backflushing.

[0038] The volume of the mixing chamber 2 is actively adjusted by the sliding plate 3, so that the paint in the mixing chamber 2 flows back into the storage tank 4, reducing the amount of residual paint in the mixing chamber 2. At the same time, the cleaning pipe 441 backwashes the filter screen 42 to solve the problem of clumping and buildup, cleans the residue in the feeding pipe 41, and the air outlet at the lower end of the air inlet pipe 442 disturbs the paint to prevent it from settling and causing stratification. This would prevent the paint from settling and causing uneven painting when the painting is restarted, ensuring the fluidity and uniformity of the paint when the painting is restarted, and improving the stability of the coating quality.

[0039] like Figures 3 to 5 As shown, the mixing chamber 2 is a vertical chamber used for mixing paint liquid. Specifically, it can be a cylindrical chamber combined with a sliding plate 3. After the paint liquid enters the mixing chamber 2 and the gas entering the mixing chamber 2 are mixed evenly, it is sprayed out by the nozzle 12 set on the left side of the mixing chamber 2.

[0040] like Figures 2 to 5 As shown, the storage tank 4 is located below the mixing chamber 2. The storage tank 4 is used to store the paint to be sprayed. The storage tank 4 includes a sealing cap 44 and a tank body 45. The sealing cap 44 is snapped into the bottom end of the mixing chamber 2, and the tank body 45 is located below the sealing cap 44.

[0041] The sealing cap 44 refers to a separate cap covering the top of the storage tank 4. It can be implemented using a ring structure with snap-fit ​​or threaded connections. The design of the sealing cap 44 snapping onto the bottom of the mixing chamber ensures that disassembly does not damage the tank body 45 structure of the storage tank 4, while maintaining the internal sealing of the storage tank 4. The tank body 45 refers to the main container for storing paint, which can be cylindrical or square. Its separate design from the sealing cap 44 facilitates independent replacement or cleaning. The tank body 45 can be designed with a standardized interface to accommodate different capacity tank body 45 modules, meeting the needs of continuous spraying or small-batch operations.

[0042] like Figures 4 to 7As shown, the sliding plate 3 is located on the upper side of the sealing cover 44. The sliding plate 3 is located inside the mixing chamber 2. The sliding plate 3 slides in the up and down direction. The sliding plate 3 changes the volume of the mixing chamber 2 below the sliding plate 3. By reducing the volume of the mixing chamber 2, the paint liquid in the mixing chamber 2 is collected, preventing the paint liquid adhering to the surface of the mixing chamber 2 from hardening when spraying stops. At the same time, when the sliding plate 3 moves to the bottom of the mixing chamber 2, it blocks the paint liquid in the mixing chamber 2 from contacting the outside air.

[0043] The storage tank 4 is positioned below the mixing chamber 2 so that when the spray gun stops working, the sliding plate 3 allows the residual paint in the mixing chamber 2 to quickly flow back to the storage tank 4 below. After the paint in the mixing chamber 2 returns to the storage tank 4, it mixes with the paint in the storage tank 4, preventing the paint in the mixing chamber 2 from being in contact with air for a long time and causing it to clump.

[0044] like Figures 4 to 6 As shown, the lower end face of the sliding plate 3 is set in a cone shape, and the cone gradually shrinks from top to bottom. The upper end face of the storage tank 4 is provided with a groove 443, which is adapted to the cone-shaped lower end face of the sliding plate 3. The groove 443 refers to the annular recessed area provided on the upper end face of the storage tank 4. The groove 443 matches the shape of the lower end face of the sliding plate 3 to limit the vertical displacement of the sliding plate 3.

[0045] The tapered shape of the lower end face of the sliding plate 3 refers to the inverted tapered geometry of the end face, which can be achieved by cutting. When the sliding plate 3 moves down, the tapered structure guides the residual paint in the mixing chamber 2 to flow along the inverted tapered structure to the tip of the tapered structure.

[0046] The matching of groove 443 with the lower end face of sliding plate 3 means that the inner wall contour of groove 443 and the conical end face form a complementary shape. Specifically, it can be achieved by CNC milling. The depth of groove 443 is the same as the height of the conical part of sliding plate 3. This structure allows the paint liquid in mixing chamber 2 to be squeezed into storage tank when the two come into contact.

[0047] By setting the volume of the mixing chamber 2 to be dynamically adjustable, the problem of cleaning the residual paint inside the mixing chamber 2 during the paint spraying pause is solved. The coordinated movement of the conical end face and the groove 443 can scrape off the residue inside the mixing chamber 2. At the same time, the mechanical seal formed effectively prevents the paint in the storage tank 4 from contacting the outside world, avoiding the situation of caking inside the mixing chamber 2 due to the pause in spraying.

[0048] like Figures 4 to 6As shown, the feed pipe 41 is installed inside the storage tank 4. The upper end of the feed pipe 41 is connected to the lower end face of the sealing cover 44. Specifically, it can be fixed by a flange or threads to ensure that the feed pipe 41 and the sealing cover 44 are disassembled synchronously. The feed pipe 41 is rigidly fixed to the lower end face of the sealing cover 44, maintaining a stable relative position with the tank body 45 during disassembly to prevent seal failure due to pipe misalignment.

[0049] A connecting pipe 43 is inserted inside the feeding pipe 41. The upper end of the connecting pipe 43 is connected to the bottom end of the conical part of the sliding plate 3. The sealing cover 44 is provided with a through hole for the connecting pipe 43 to pass through, extending into the feeding pipe 41 through the through hole. The sliding and telescopic ends of the feeding pipe 41 and the connecting pipe 43 are rigid pipes, preferably made of corrosion-resistant alloy material. The connecting pipe 43 is also a rigid pipe, preferably made of corrosion-resistant alloy material. The rigid design of the sliding ends of the connecting pipe 43 and the feeding pipe 41 ensures both telescopic movement and sealing between them. To further ensure sealing, a flexible ring is provided on the side of the sliding plate 3 that abuts against the side wall of the mixing chamber 2. The flexible ring is an annular sealing element made of elastic deformable material, specifically rubber or silicone, and its cross-sectional shape can be rectangular or trapezoidal. This flexible ring fills the assembly gap between the sliding plate 3 and the side wall of the mixing chamber 2 through its own deformation.

[0050] Dynamic sealing refers to maintaining a sealed state at the contact surface during the movement of the sliding plate 3 by utilizing the elastic deformation capability of the flexible ring. Specifically, this can be achieved through a pre-compression installation method, which allows the flexible ring to form an initial compression seal with the side wall of the mixing chamber 2 when it is stationary.

[0051] A limiting component is provided between the feeding pipe 41 and the connecting pipe 43 to prevent them from rotating around their axis. Specifically, a longitudinal protrusion is provided on the outer wall of the connecting pipe 43, and a corresponding guide groove is provided on the inner wall of the feeding pipe 41. The protrusion is embedded in the guide groove and slides axially. This structure maintains the circumferential positioning of both components during the up-and-down movement of the connecting pipe 43, preventing rotational offset and ensuring that the cleaning pipe 441 is directly aligned with the opening of the connecting pipe 43.

[0052] like Figure 4 and Figure 7 As shown, the lower half of the feeding pipe 41 is a flexible pipe. The flexible section of the feeding pipe 41 can be bent. The lower end of the feeding pipe 41 abuts against the bottom surface of the storage tank 4. The filter screen 42 is set at the lower end of the feeding pipe 41. The flexible section refers to the pipe body made of deformable material, which can be implemented by rubber hose or corrugated pipe. The bending deformation is achieved by the elasticity of the material. The lower end abutting means that the lower end of the feeding pipe 41 is in contact with the bottom of the storage tank 4. Specifically, the position of the pipe opening can be maintained by gravity.

[0053] Specifically, when the flexible section bends, its end always adheres to the bottom surface of the storage tank 4. When the shape or size of the storage tank 4 changes, the flexible section compensates for the height difference through deformation, avoiding the formation of a gap between the pipe opening and the bottom of the tank. When paint settles inside the storage tank 4, the pipe opening continues to contact the bottom area of ​​the tank, and the clumps of material accumulated below the filter screen 42 are disturbed by the liquid flow, thus making it less likely to clog the filter screen 42.

[0054] Compared to existing technologies, traditional siphon spray guns use a rigidly connected feed pipe 41, which easily creates suction dead zones when the shape of the tank 45 changes, resulting in clumps remaining below the filter screen 42. The flexible section eliminates this rigid limitation, ensuring the pipe opening always contacts the bottom of the tank, preventing material from accumulating and solidifying below the filter screen 42. The flexible section solves the flow blockage problem caused by material accumulation below the filter screen 42, and also allows the feed pipe 41 to be adapted to storage tanks 4 of different sizes.

[0055] like Figure 6 and Figure 7 As shown, the opening at the lower end of the feed pipe 41 is outwardly flared, and the filter screen 42 is located at the lower opening of the feed pipe 41. The outwardly flared opening refers to the geometric shape of the pipe end expanding outwards, which can be achieved using a trumpet-shaped or funnel-shaped structure. This design creates a diffusion area at the end of the paint flow path. The filter screen 42 is a filtering component covering the opening, which can be a metal filter screen 42 or a plastic perforated plate, and its pore size can be adjusted according to the paint viscosity.

[0056] Specifically, when paint in storage tank 4 is conveyed through feed pipe 41, the outward-expanding opening increases the contact area between filter screen 42 and paint. During this process, solid particles are blocked by filter screen 42, and the outward-expanding opening increases the filtration area of ​​filter screen 42, preventing agglomerates from accumulating in the filtration area and causing filter screen 42 to become clogged and unable to supply paint normally. The cooperative layout of filter screen 42 and outward-expanding opening forms a filtration interface, maintaining filtration efficiency while reducing the risk of the filter media surface being completely covered.

[0057] In some specific embodiments, the inclination angle of the outwardly flared opening can be from 15° to 45°, and the edge of the filter screen 42 is fixed to the edge of the opening by snaps. For example, a corrugated structure made of stainless steel with a corrugation depth of 2 mm can be used to enhance structural strength and create local turbulence, reducing the accumulation of agglomerates.

[0058] The combination of the outward-expanding structure and the filter screen 42 reduces the accumulation of agglomerated material below the filter screen 42, preventing clogging of the filter screen 42 due to paint sedimentation. The outward-expanding opening creates a larger filtration area, avoiding clogging on the filter screen 42 and ensuring the continuity of paint delivery.

[0059] like Figures 3 to 5As shown, the cleaning pipe 441 and the air inlet pipe 442 are integrated in the sealing cover 44. Specifically, an embedded pipe structure can be adopted to centrally arrange the pipe interfaces and avoid interference caused by direct connection with the tank body 45. When the sliding plate 3 is at the bottom, the openings on the cleaning pipe 441 and the connecting pipe 43 are directly opposite each other. The cleaning pipe 441 and the air inlet pipe 442 are externally connected to an air intake device. The air inlet pipe 442 is connected to the inside of the storage tank 4. The air inlet pipe 442 pumps gas from the top of the paint liquid into the storage tank 4, which increases the pressure inside the storage tank 4. After the paint liquid passes through the connecting pipe 43 along the feeding pipe 41, it enters the mixing chamber 2 through the opening on the connecting pipe 43 and is sprayed out from the nozzle 12 by the gas.

[0060] When the sliding plate 3 is at its lowest position, the cleaning pipe 441 is connected to the opening of the connecting pipe 43. The gas in the cleaning pipe 441 passes through the connecting pipe 43 and is back-blown into the storage tank 4 by the feeding pipe 41. When the gas enters the storage tank 4 from the lower end of the feeding pipe 41, it back-flushes the clumps on the outside of the filter screen 42 at the opening of the feeding pipe 41, so that the filtering performance of the filter screen 42 is restored. At the same time, the gas is discharged from the lower end of the feeding pipe 41, so that the paint in the storage tank 4 is stirred. Before spraying, the paint in the storage tank 4 is mixed evenly to prevent uneven spraying caused by sedimentation.

[0061] like Figures 3 to 6 As shown, a locking block 71 and an elastic element 72 are provided inside the sealing cover 44. The locking block 71 is vertically installed inside the sealing cover 44 and slides in the vertical direction. The elastic element 72 is installed between the locking block 71 and the storage tank 4. When the sliding plate 3 is at the lowest end, the sliding plate 3 drives the locking block 71 to extend into the air inlet pipe 442 to block the storage tank 4 from communicating with the outside.

[0062] The locking block 71 is a cylindrical component that can slide up and down along the sealing cover 44. Specifically, it can be implemented as a sliding block with a guide groove. Its movement trajectory intersects with the air intake pipe 442. When the locking block 71 is at its lowest point, it blocks the gas passage of the air intake pipe 442. The elastic element 72 is a mechanical element that provides a restoring force. Specifically, it can be implemented as a compression spring. It is installed between the locking block 71 and the sealing cover 44. It is used to restore the locking block 71 to its initial position after the pressure of the sliding plate 3 is released, so that the gas passage of the air intake pipe 442 can be restored.

[0063] Specifically, when the painting operation is paused, the sliding plate 3 is pressed down to its lowest position, and its conical lower end face contacts the locking block 71, generating a downward thrust. This pushes the locking block 71 to overcome the resistance of the elastic element 72 and insert it into the air intake pipe 442, forming a physical blockage. At this time, the gas in the air intake pipe 442 cannot enter the storage tank 4. When the painting operation resumes, the sliding plate 3 moves up to release the pressure on the locking block 71, and the elastic element 72 pushes the locking block 71 to automatically exit the air intake pipe 442, restoring the gas passage.

[0064] like Figures 2 to 5 As shown, the adjustment component 5 includes a pressure rod 51 and a connecting plate 52. The pressure rod 51 is vertically mounted on the handle 11 and slides up and down along the mixing chamber 2. The upper end of the mixing chamber 2 has a through hole for the pressure rod 51 to pass through. The lower end of the pressure rod 51 is provided with a connecting plate 52. A snap-fit ​​structure is provided between the connecting plate 52 and the sliding plate 3. When snap-fitted, the connecting plate 52 and the sliding plate 3 move up and down synchronously.

[0065] The pressure rod 51 refers to the operating component that is set outside the spray gun and extends in the vertical direction. Specifically, it can be achieved by sliding a metal rod to the spray gun housing. The pressure rod 51 is manually controlled to move up and down, thereby causing the connecting plate 52 to move.

[0066] Among them, the connecting plate 52 refers to the transition structure connecting the pressure rod 51 and the sliding plate 3. Specifically, it can be implemented by a plate-shaped part with a guide groove. The connecting plate 52 and the pressure rod 51 transmit the motion trajectory through a rigid connection.

[0067] The snap-fit ​​structure refers to the mechanical locking device that enables detachable linkage between the connecting plate 52 and the sliding plate 3. Specifically, it can be achieved by using a pin and a slot. In the locked state, the snap-fit ​​structure makes the connecting plate 52 and the sliding plate 3 form a rigid connection.

[0068] Specifically, when the locking structure is in the locked state, the operator manually pushes the pressure rod 51 to slide up and down along the mixing chamber 2. The pressure rod 51 drives the connecting plate 52 to move synchronously. The connecting plate 52 transmits the driving force to the sliding plate 3 through the locking structure, causing the sliding plate 3 to move vertically within the mixing chamber 2, thereby changing the effective volume of the mixing chamber 2. During the spraying pause phase, pressing down the pressure rod 51 moves the sliding plate 3 to its lowest position, reducing the volume of the mixing chamber 2 to its minimum. This causes the residual paint in the mixing chamber 2 to flow back to the storage tank 4, preventing the paint from remaining inside the mixing chamber 2 and causing it to dry and harden. The locked state of the locking structure prevents the sliding plate 3 from shifting due to equipment vibration or misoperation, ensuring the stability of the volume adjustment of the mixing chamber 2.

[0069] The combination of pressure rod 51 and sliding plate 3 solves the problem of paint residue drying in mixing chamber 2 when spraying is paused, prevents sediment in storage tank 4 from accumulating at filter screen 42, reduces the risk of clogging caused by paint curing inside spray gun, ensures the continuity and uniformity of paint flow when spraying is restarted, and improves the spraying quality of coating on oil casing surface.

[0070] like Figure 7 and Figure 8As shown, the limiting component 6 includes a spring block 61 and a slot 62. The spring block 61 is telescopically mounted on the side wall of the mixing chamber 2. The spring block 61 telescopically extends and retracts perpendicular to the axis of the mixing chamber 2. The spring block 61 can be implemented by using a spring and a metal protrusion. When the sliding plate 3 moves upward from the bottom, the spring block 61 provides resistance to limit the upward movement of the sliding plate 3. The slot 62 refers to a continuously distributed ring-shaped limiting structure. Specifically, it can be implemented by using a ring-shaped groove formed by machining. The ring-shaped layout ensures contact stability at any angle.

[0071] Specifically, during the paint spraying pause, the sliding plate 3 is manually moved to the bottom of the mixing chamber 2, where it abuts against the sealing cover 44. The spring block 61 extends and engages with the slot 62 on the connecting plate 52, restricting the upward movement of the sliding plate 3. When the paint spraying pause resumes, the gas in the cleaning pipe 441 enters the storage tank 4 from the lower end of the feeding pipe 41. The gas mixes the paint in the storage tank 4, causing the stagnant paint to settle evenly. As the pressure inside the storage tank 4 increases, the sliding plate 3 pushes... The moving connecting plate 52 overcomes the resistance provided by the spring block 61, causing the spring block 61 to retract. The sliding plate 3 moves past the spring block 61 to the uppermost end of the mixing chamber 2. The sliding plate 3 moves upward, and the opening of the connecting pipe 43 is misaligned with the cleaning pipe 441. The air passage between the cleaning pipe 441 and the storage tank 4 is disconnected. After the sliding plate 3 moves upward, the locking block 71 moves upward, releasing the blockage on the air inlet pipe 442. After the gas in the air inlet pipe 442 enters the storage tank 4, it transports the paint liquid from the storage tank 4 to the mixing chamber 2 through the feeding pipe 41.

[0072] Working principle: When the spray gun is temporarily stopped, manually push the pressure rod 51 into the mixing chamber 2. The sliding plate 3 moves from top to bottom along the mixing chamber 2. The sliding plate 3 collects the paint on the side wall of the mixing chamber 2 and flows back into the storage tank 4 through the opening on the side of the connecting pipe 43. The spring block 61 is stuck in the slot 62 on the connecting plate 52. The sliding plate 3 presses the locking block 71 down, and the locking block 71 blocks the air inlet pipe 442.

[0073] When the spray gun is used again, the external air pump pumps the gas from the cleaning pipe 441 through the connecting pipe 43 into the feeding pipe 41. The airflow in the feeding pipe 41 back-blowing the filter screen 42 set at the lower opening of the feeding pipe 41 removes the clumps and materials adhering to the filter screen 42, restoring the filtering performance of the filter screen 42. At the same time, the gas discharged from the feeding pipe 41 turns upward from the bottom of the storage tank 4, mixing the paint in the storage tank 4 and preventing the paint from settling when it is still, which would prevent normal painting.

[0074] After the pressure inside the storage tank 4 increases, the connecting plate 52 overcomes the resistance of the spring block 61, causing the spring block 61 to contract. The sliding plate 3 moves past the spring block 61 to the uppermost end of the mixing chamber 2. The sliding plate 3 moves upward, and the opening of the connecting pipe 43 is misaligned with the cleaning pipe 441. The air passage between the cleaning pipe 441 and the storage tank 4 is disconnected. After the sliding plate 3 moves upward, the locking block 71 moves upward, releasing the blockage on the air inlet pipe 442. After the gas in the air inlet pipe 442 enters the storage tank 4, it transports the paint from the storage tank 4 to the mixing chamber 2 through the feeding pipe 41 for normal painting.

[0075] In addition, the present invention includes a process for painting the surface of oil casing, using the aforementioned oil casing surface painting equipment, the process comprising the following steps:

[0076] S1. When the oil casing painting operation needs to be paused, the sliding plate 3 is driven to move down to the bottom of the mixing chamber 2 by adjusting the component 5. The sliding plate 3 compresses the space of the mixing chamber 2 and pushes the residual paint in the mixing chamber 2 back into the storage tank 4. At the same time, the sliding plate 3 moves down and drives the connecting pipe 43 to move down, so that the opening on the connecting pipe 43 is aligned and connected with the cleaning pipe 441.

[0077] S2. Before restarting the painting process, gas is introduced into the connecting pipe 43 through the cleaning pipe 441. The gas is blown out downwards and in the opposite direction through the feeding pipe 41 to backwash the filter screen 42 at the bottom of the feeding pipe 41 and remove the clumps on the filter screen 42. At the same time, the gas enters the bottom of the storage tank 4 and rises upwards to stir and mix the paint in the storage tank 4 and eliminate paint separation.

[0078] S3. After the paint is mixed evenly, the sliding plate 3 is driven to move upward and reset by adjusting component 5. The opening of the connecting pipe 43 is misaligned and disconnected from the cleaning pipe 441. The air inlet pipe 442 resumes ventilation. Under the action of air pressure, the paint enters the mixing chamber 2 through the feeding pipe 41 and the connecting pipe 43, and is sprayed on the surface of the oil casing by the nozzle 12.

[0079] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A spray painting device for the surface of oil casing, comprising: The handle, nozzle, and storage tank are characterized by further comprising: a mixing chamber, a feeding pipe, a cleaning pipe, an adjusting component, and a limiting component; the mixing chamber is vertically disposed on the right side of the nozzle; a storage tank is disposed below the mixing chamber, and a sliding plate that slides up and down is disposed on the upper side of the storage tank, the sliding plate sliding up and down to change the volume of the mixing chamber; the feeding pipe is disposed inside the storage tank, with its lower end abutting against the bottom of the storage tank, a filter screen is disposed at the lower end of the feeding pipe, and a connecting pipe that slides up and down is disposed inside the feeding pipe, ensuring the sealing between the connecting pipe and the feeding pipe while sliding up and down, the upper end of the connecting pipe is connected to the lower end face of the sliding plate, and an opening is disposed on the side of the connecting pipe; the cleaning pipe is disposed on the storage tank, and when the sliding plate is at its lowest position, the cleaning pipe is directly opposite the opening; an air inlet pipe is disposed on the storage tank, pumping gas into the storage tank; The adjusting component moves the sliding plate up and down along the mixing chamber, and the limiting component is set on the inner wall of the mixing chamber, which applies resistance to the upward movement of the sliding plate. The storage tank is equipped with a vertical locking block that slides up and down. An elastic element is installed between the locking block and the storage tank. When the sliding plate is at the bottom, the locking block extends into the air inlet pipe, blocking the connection between the storage tank and the outside world through the air inlet pipe. The lower end face of the sliding plate is conical, and the upper end face of the storage tank is provided with a groove that matches the lower end face of the sliding plate; a flexible ring is provided on the side of the sliding plate that abuts against the side wall of the mixing chamber.

2. The oil casing surface painting equipment according to claim 1, characterized in that, The adjustment assembly includes a pressure rod and a connecting plate. The pressure rod is vertically mounted on the handle and slides up and down along the mixing chamber. The lower end of the pressure rod is provided with a connecting plate, and a snap-fit ​​structure is provided between the connecting plate and the sliding plate. When snap-fitted, the connecting plate and the sliding plate move up and down synchronously.

3. The oil casing surface painting equipment according to claim 1, characterized in that, The lower half of the feeding pipe is a flexible pipe, which can be bent, and the lower end of the feeding pipe abuts against the bottom of the storage tank.

4. The oil casing surface painting equipment according to claim 2, characterized in that, The limiting component includes a spring block and a slot. The spring block is telescopically mounted on the inner wall of the mixing chamber and extends radially along the mixing chamber. The slot is annularly mounted on the side wall of the connecting plate.

5. The oil casing surface painting equipment according to claim 4, characterized in that, The storage tank includes a sealing cover and a tank body. The sealing cover is snapped into the bottom of the mixing chamber. The cleaning pipe and the air inlet pipe are located inside the sealing cover. The upper end of the feeding pipe is connected to the lower end face of the sealing cover. The tank body is located on the lower side of the sealing cover. A limiting device is provided between the feeding pipe and the connecting pipe to restrict the relative rotation between the feeding pipe and the connecting pipe.

6. The oil casing surface painting equipment according to claim 1, characterized in that, The opening at the lower end of the feed pipe is outward-expanding, and the filter screen is installed at the lower opening of the feed pipe.

7. A painting process for the surface of an oil casing, characterized in that, The process of using the oil casing surface painting equipment according to any one of claims 1-6 includes the following steps: S1. When the painting operation of the oil casing needs to be paused, the sliding plate is driven to move down to the bottom of the mixing chamber by adjusting the component. The sliding plate compresses the space of the mixing chamber and pushes the residual paint in the mixing chamber back into the storage tank. At the same time, the downward movement of the sliding plate drives the connecting pipe to move down, so that the opening on the connecting pipe is aligned and connected with the cleaning pipe. S2. Before restarting the painting process, gas is introduced into the connecting pipe through the cleaning pipe. The gas is blown out in the opposite direction downward through the feeding pipe to backwash the filter screen at the bottom of the feeding pipe and remove the clumps on the filter screen. At the same time, the gas enters the bottom of the storage tank and rises upward to stir and mix the paint in the storage tank and eliminate paint separation. S3. After the paint is mixed evenly, the sliding plate is driven to move upward and reset by adjusting the component. The opening of the connecting pipe is disconnected from the cleaning pipe, the air inlet pipe resumes ventilation, and the paint enters the mixing chamber through the feeding pipe and connecting pipe under air pressure. The paint is then sprayed onto the surface of the oil casing through the nozzle.

Images