Axial-flow type check valve for conveying crude oil

Abstract

The utility model relates to the technical field of valve manufacturing, in particular to an axial flow type check valve for conveying crude oil, which comprises a valve body, the valve body comprises an inlet cavity, an outlet cavity and a valve cover cavity, the inlet cavity and the outlet cavity are horizontally arranged, the valve cover cavity is positioned on the upper portion of the valve body, and a valve seat is arranged on a partition wall at the joint of the inlet cavity and the valve cover cavity. A cylindrical sliding valve is arranged in a cylinder at the lower end of the valve cover, an inner hole of the cylinder of the valve cover is in movable fit with the outer circle of the sliding valve, a spring is arranged between an upper spring seat at the lower end of an adjusting screw arranged on the valve cover and the cylinder bottom of the sliding valve, and a valve port is formed between a sealing gasket on the lower end face of the sliding valve and a valve seat. The sliding valve has the functions of eliminating mutual impact of parts in the valve and resisting sulfur and wax precipitation, and has the advantages that the noise of the valve is greatly reduced, the sealing performance of a valve port is improved, and the service life of the valve is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of valve manufacturing, in particular to an axial flow check valve for transporting crude oil. Background Art

[0002] In a pipeline system for transporting crude oil, in order to prevent the reverse flow of crude oil, a check valve is usually used. However, due to the high gas content (mainly hydrogen sulfide) in the crude oil, the sliding valve of the check valve is prone to repeated up and down movements, resulting in a violent impact on the valve cover and valve seat, exacerbating the damage of the check valve element and valve seat, and generating unacceptable noise. After actual measurement of the lift check valve, the noise reaches more than 90 decibels; in addition, hydrogen sulfide is a highly corrosive gas, which is likely to cause brittle fracture of the valve parts; again, the high wax content in the crude oil condenses on the surface of the valve element and the sealing pair, not only affecting the movement of the sliding valve, but also deteriorating the sealing. Therefore, ordinary check valves are difficult to meet the use requirements of crude oil transportation pipelines. Summary of the Utility Model

[0003] The utility model provides an axial flow check valve for transporting crude oil, which has the functions of eliminating mutual impact of internal parts of the valve, resisting sulfur and wax deposition, low noise, high sealing performance and long service life, and solves the problem that the existing check valve is not suitable for transporting crude oil.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] An axial flow check valve for transporting crude oil includes a valve body. The valve body includes a horizontally arranged inlet cavity and an outlet cavity, as well as a valve cover cavity located at the upper part of the valve body. A valve seat is provided on the partition wall at the connection between the inlet cavity and the valve cover cavity. A cylindrical sliding valve is arranged in the cylinder at the lower end of the valve cover. The inner hole of the valve cover cylinder is in movable fit with the outer circle of the sliding valve. A spring is arranged between the upper spring seat at the lower end of the adjusting screw arranged on the valve cover and the bottom of the cylinder of the sliding valve. A valve port is formed between the sealing gasket on the lower end surface of the sliding valve and the valve seat. An adjusting sleeve is arranged in the sliding valve, and adjustable flow holes are arranged on the side walls of the sliding valve and the adjusting sleeve.

[0006] Preferably, the adjustable flow hole is composed of an outer adjusting hole arranged on the side wall of the sliding valve and an inner adjusting hole arranged at the same height on the side wall of the adjusting sleeve corresponding to the outer adjusting hole, and the diameter of the inner adjusting hole is the same as that of the outer adjusting hole.

[0007] Preferably, several notches are arranged at the upper end of the adjusting sleeve, a pressing plate one for fixing the adjusting sleeve is arranged above the adjusting sleeve, internal threads are arranged on the inner wall of the middle section of the sliding valve, and the pressing plate one is threadedly connected with the inner wall of the sliding valve, and a central hole is arranged in the center of the pressing plate one.

[0008] Preferably, a stepped surface is provided on the lower end surface of the slide valve, and a sealing gasket is provided on the outer shoulder of the lower end surface of the slide valve. The sealing gasket is annular, and a pressing plate two for fixing the sealing gasket is provided on the stepped surface inside the sealing gasket. The pressing plate two is fixed to the bottom of the slide valve by screws two, and a valve port of the check valve is formed between the sealing gasket and the upper end surface of the valve seat.

[0009] Preferably, an upper spring seat is provided at the lower end of the adjusting screw. The upper spring seat is in the shape of a stepped shaft, and a central protrusion at the bottom of the slide valve forms a lower spring seat. The spring is arranged between the upper spring seat and the lower spring seat.

[0010] Preferably, the center of the valve cover has a cylindrical protrusion upwards. The center of the cylinder has a stepped hole with a larger upper diameter and a smaller lower diameter. There is a thread in the upper hole, and a groove is provided on the inner wall of the lower hole. The adjusting screw is screwed into the thread of the upper hole, and an O-ring one is provided in the groove of the lower hole.

[0011] Preferably, a locknut is provided on the adjusting screw, and a protective cover is provided at the adjusting screw and the locknut. There is a thread on the outer periphery of the cylinder of the valve cover, and the protective cover is screwed onto the cylinder of the valve cover.

[0012] Preferably, the valve cover cavity in the upper part of the valve body is inclined towards the outlet cavity side. The center lines of the inlet cavity and the outlet cavity are on the same straight line, and the included angle between the center line of the valve cover cavity and the center line of the outlet cavity is 50 - 60 degrees.

[0013] Preferably, the valve seat is in the shape of a stepped cylinder, and the upper edge of the valve seat is provided with an outward - turned circular ring surface. A valve port of the check valve is formed between the sealing gasket and the circular ring surface of the valve seat; the cylinder at the lower end of the valve cover extends to the middle of the valve cover cavity, and an O - ring two is provided between the outer wall of the upper section of the cylinder and the inner wall of the upper section of the valve cover cavity.

[0014] Preferably, the valve body material is a sulfur - resistant nickel - based alloy. If the valve body material is cast iron, then the non - mating inner surface of the valve body cavity is coated with a sulfur - resistant nickel - based corrosion - resistant alloy layer; the main parts are made of 826 or 316L stainless steel, and the surfaces of the inner hole of the cylinder at the lower end of the valve cover, the inner and outer surfaces of the slide valve cylinder, the outer circular surface of the adjusting sleeve, and the surface of the valve seat are all coated with a Teflon non - stick layer.

[0015] Compared with the prior art, the beneficial effects of the present utility model are:

[0016] The present utility model provides an axial flow check valve for transporting crude oil, effectively solving the problem that in the pipeline system for transporting crude oil in the prior art, when a common check valve is used, the slide valve of the check valve moves up and down repeatedly, causing a violent impact on the valve cover and the valve seat, aggravating the damage of the check valve elements and the valve seat and the seal failure, and generating unacceptable noise.

[0017] Compared with the check valve of the prior art, the device of the present utility model has the advantages of eliminating the mutual impact of the parts inside the valve, anti-sulfur and anti-wax deposition functions, greatly reducing the noise of the valve, improving the sealing performance of the valve port and extending the service life of the valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic cross-sectional view of the overall structure of an embodiment of the present utility model.

[0019] Figure 2 is Figure 1 the schematic A-A cross-sectional view in

[0020] In the figure: 1. protective cover, 2. adjusting screw, 3. locking nut, 4. valve cover, 5. O-ring seal I, 6. upper spring seat, 7. screw I, 8. washer, 9. O-ring seal II, 10. pressing plate I, 11. sliding valve, 12. spring, 13. adjusting sleeve, 14. valve body, 15. valve seat, 16. screw II, 17. pressing plate II, 18. gasket, a. notch, b. external adjustment hole, c. internal adjustment hole, d. adjustable throttle hole, h. valve seat hole, w. partition wall, v. valve port. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0022] In a pipeline system for transporting crude oil, in order to prevent the reverse flow of crude oil, a check valve is usually used. However, due to the high gas content (mainly hydrogen sulfide) in the crude oil, the sliding valve of the check valve is prone to repeated up and down movements, causing violent impacts on the valve cover and valve seat, aggravating the damage of the check valve components and the valve seat, and generating unacceptable noise. Through actual measurement of the lift check valve, the noise reaches more than 90 decibels; in addition, hydrogen sulfide is a highly corrosive gas, which is likely to cause brittle fracture of the valve parts; again, the high wax content in the crude oil condenses on the surfaces of the valve components and the sealing pair, not only affecting the movement of the sliding valve, but also deteriorating the sealing. Therefore, ordinary check valves are difficult to meet the transportation of crude oil.

[0023] Figure 1 It is a schematic cross-sectional view of the overall structure of this embodiment, Figure 2 is Figure 1Schematic cross-sectional view taken along line A-A. In this embodiment, an axial check valve for transporting crude oil is provided, which includes a valve body. The valve body includes a horizontally arranged inlet cavity, an outlet cavity, and a valve cover cavity located at the upper part of the valve body. A valve seat is provided on the partition wall at the connection between the inlet cavity and the valve cover cavity. A cylindrical slide valve is arranged inside the cylinder at the lower end of the valve cover. The inner hole of the valve cover cylinder is in moving fit with the outer circle of the slide valve. A spring is provided between the upper spring seat at the lower end of the adjusting screw provided on the valve cover and the bottom of the cylinder of the slide valve. A valve port is formed between the sealing gasket on the lower end surface of the slide valve and the valve seat. An adjusting sleeve is arranged inside the slide valve, and adjustable throttle holes are provided on the side walls of the slide valve and the adjusting sleeve. When transporting crude oil, the slide valve moves upward under the push of hydrodynamic force, overcoming the pressure of the spring, the weight of relevant parts, and the friction force. The valve port of the check valve opens to supply oil to the downstream. When the oil supply stops, the slide valve moves downward under the action of the spring and the weight of relevant parts to close the valve port and prevent the reverse flow of crude oil. Since a large amount of hydrogen sulfide gas is contained in the crude oil (the gas-oil ratio is generally greater than 20%), if a common type of check valve is used, the slide valve will rise and fall very frequently and violently, causing strong impacts between the slide valve and the top parts and the valve seat. This will not only accelerate the damage of the parts inside the valve but also generate harsh noises. In this embodiment, an adjusting sleeve is arranged inside the slide valve, and adjustable throttle holes are provided on the side walls of the slide valve and the adjusting sleeve. In this way, when the slide valve rises and falls, the crude oil inside the slide valve cavity must enter or exit through the throttle holes, and the size of the throttle holes can be adjusted by the adjusting sleeve. Due to the throttling effect of the throttle holes, the lifting and lowering speed of the slide valve is limited, and the slide valve will not rise and fall very frequently and violently. Therefore, the rising and falling speed of the slide valve can be controlled within a suitable range, thereby eliminating the mutual impact between parts and greatly reducing the resulting noise.

[0024] The adjustable throttle hole is composed of an outer throttle hole provided on the side wall of the slide valve and an inner throttle hole provided at the same height on the side wall of the adjusting sleeve corresponding to the outer throttle hole. The diameter of the inner throttle hole is the same as that of the outer throttle hole. In this embodiment, the outer throttle hole and the inner throttle hole are respectively provided at the same position on the side walls of the slide valve and the adjusting sleeve. The outer throttle hole and the inner throttle hole are combined to form an adjustable throttle hole. When the adjusting sleeve rotates, the inner throttle hole and the outer throttle hole can completely coincide or partially coincide. When the inner throttle hole and the outer throttle hole completely coincide, the flow rate of the adjustable throttle hole is the largest, and when the inner throttle hole and the outer throttle hole partially coincide, the flow rate of the adjustable throttle hole decreases, thereby realizing the flow rate adjustment.

[0025] The upper end of the adjusting sleeve is provided with a plurality of notches. Above the adjusting sleeve, there is a first pressing plate for fixing the adjusting sleeve. The inner wall of the middle section of the slide valve is provided with threads, and the first pressing plate is threadedly connected to the inner wall of the slide valve. The center of the first pressing plate is provided with a central hole. The notches at the upper end of the adjusting sleeve are used to rotate the adjusting sleeve. When the relative position between the adjusting sleeve and the slide valve is determined, that is, when the flow rate of the adjustable throttle hole formed by the outer adjusting hole on the side wall of the slide valve and the inner adjusting hole on the adjusting sleeve is determined, the position of the adjusting sleeve is fixed by the first pressing plate screwed to the inner wall of the slide valve, that is, the flow rate of the adjustable throttle hole is fixed. In this embodiment, the first pressing plate is an annular plate, and a central hole is provided in the center for the medium to flow through and to avoid the spring.

[0026] The lower end face of the slide valve is provided with a stepped surface, and a sealing gasket is provided on the outer periphery of the lower end face of the slide valve. The sealing gasket is annular. On the stepped surface inside the sealing gasket, there is a second pressing plate for fixing the sealing gasket. The second pressing plate is fixed to the bottom of the slide valve by screws. A valve port of the check valve is formed between the sealing gasket and the valve seat. In this embodiment, the two stepped surfaces provided on the lower end face of the slide valve are respectively used to position the sealing gasket and the second pressing plate. The second pressing plate is used to press the sealing gasket, and the second pressing plate is fixed to the lower end face of the slide valve by a plurality of screws. The outer edge of the second pressing plate presses on the inner edge of the sealing gasket to fix the sealing gasket, and the outer edge of the sealing gasket and the valve seat form the valve port of the check valve.

[0027] The lower end of the adjusting screw is provided with an upper spring seat. The upper spring seat is in the shape of a stepped shaft. The central protrusion at the bottom of the slide valve forms a lower spring seat. The spring is arranged between the upper spring seat and the lower spring seat. Both the upper spring seat and the lower spring seat are provided with protrusions in the center to limit the lateral movement of the spring. Rotating the adjusting screw drives the upper spring seat to move up and down to adjust the pre-pressure of the spring, thereby controlling the opening force of the check valve port.

[0028] The center of the valve cover has a cylinder protruding upward. The center of the cylinder has a stepped hole with a larger diameter at the top and a smaller diameter at the bottom. There are threads in the upper hole, and a groove is provided on the inner wall of the lower hole. The adjusting screw is screwed into the threads in the upper hole, and an O-ring is arranged in the groove of the lower hole. The threads in the upper hole are used to be screwed with the adjusting screw, allowing the adjusting screw to rotate and move up and down in the hole.

[0029] A locknut is provided on the adjusting screw. A protective cover is provided at the adjusting screw and the locknut. The outer periphery of the cylinder of the valve cover is machined with threads, and the protective cover is screwed onto the threads of the valve cover. The protective cover is used to protect the adjusting screw and the locknut from the influence of the external environment, such as dust, moisture or other pollutants, and also plays a safety protection role to prevent accidental touch or operation.

[0030] The valve cover cavity at the upper part of the valve body is inclined towards the outlet cavity. The center lines of the inlet cavity and the outlet cavity are on the same straight line, and the included angle between the center line of the valve cover cavity and the center line of the outlet cavity is 50 - 60 degrees. The inclination of the valve cover cavity at the upper part of the valve body towards the outlet cavity helps the crude oil flow more smoothly from the inlet cavity to the outlet cavity, reducing the resistance of the crude oil flow.

[0031] The described valve seat is in the shape of a stepped cylinder, and the upper edge of the valve seat is provided with an outward - turned circular ring surface. A check valve orifice is formed between the sealing gasket and the circular ring surface of the valve seat; the cylinder at the lower end of the valve cover extends to the middle of the valve cover cavity. An O - ring seal II is provided between the outer wall of the upper section of the cylinder and the inner wall of the upper section of the valve cover cavity. The O - ring seal II is used to provide sealing between the valve cover and the valve body. The upper edge of the valve seat is provided with an outward - turned circular ring surface, and this circular ring surface is used to fix the axial position of the valve seat and dock with the sealing gasket.

[0032] The valve body material is a sulfur - resistant nickel - based alloy. If the valve body material is cast iron, then the non - mating inner surface of the valve body cavity is coated with a sulfur - resistant nickel - based corrosion - resistant alloy layer; the main parts are made of 826 or 316L stainless steel, and the surfaces of the inner hole of the cylinder at the lower end of the valve cover, the inner and outer surfaces of the sliding valve cylinder, the outer circular surface of the adjusting sleeve, and the surface of the valve seat are all coated with a Teflon non - stick layer.

[0033] When transporting crude oil, the sliding valve 11 moves upward under the push of hydrodynamic force, overcoming the pressure of the spring 12 and the weights and frictions of related parts, and the valve orifice v opens to supply oil to the downstream; when the oil supply stops, the sliding valve 11 moves downward under the action of the spring 12 and the weights of related parts to close the valve orifice v to prevent the reverse flow of crude oil.

[0034] The measures in this embodiment to eliminate the mutual impact of the parts inside the valve and reduce noise are as follows:

[0035] Since crude oil always contains a large amount of gas (the gas - oil ratio is generally greater than 20%), if a common - type check valve is used, then the sliding valve or the valve core will rise and fall very frequently and violently, causing impacts between the sliding valve and the top parts and the valve seat. This will not only accelerate the damage of the parts and the destruction of the seal, but also generate harsh noises. In this embodiment, when the sliding valve 11 rises and falls, the oil in the inner cavity of the sliding valve 11 must enter or exit through an adjustable throttle hole, and the size of the adjustable throttle hole d can be adjusted. Due to the throttling effect of the adjustable throttle hole d, the rising and falling speeds of the sliding valve 11 can be controlled within a suitable range, thus eliminating the mutual impact between the parts and greatly reducing the resulting noise.

[0036] The anti-sulfur performance of this embodiment is mainly obtained by using materials or coatings with anti-sulfur performance. For this purpose, metal internal parts such as the slide valve 11, adjusting sleeve 13, first pressing plate 10, spring 12, upper spring seat 6, adjusting screw 12, locknut 3, valve seat 15, second pressing plate 17, and screw 16 are all made of 826 or 316L stainless steel; the material of the valve body 14 is preferably a nickel-based alloy with good anti-sulfur performance. If cast iron is used, after casting, normalizing and tempering processes should be used to control the hardness within the range of HB178 to HB125, and the non-mating surfaces of the inner cavity should be coated with an anti-sulfur nickel-based corrosion-resistant alloy layer; in addition, the surfaces of all connecting screws should also be coated with a nickel-phosphorus coating.

[0037] The measure to prevent wax deposition in this embodiment is to coat the surfaces of all internal parts, especially the surfaces with relative movement, such as the inner hole surface of the lower cylinder of the valve cover 4, the inner and outer surfaces of the cylinder of the slide valve 11, the outer cylindrical surface of the adjusting sleeve 13, and the surface of the valve seat 15 with a Teflon non-stick layer. This can greatly slow down the wax deposition process of the check valve. After using for a long time, the adjustable orifice d may be blocked, and wax may also adhere to the sealing pair of the valve port v. Therefore, it is necessary to regularly disassemble it online and clean the internal parts and the inner cavity of the valve body with a wax remover, or heat-clean the valve. For this purpose, stop valves should be installed upstream and downstream of the valve. Close the stop valves during cleaning and open them after cleaning. In addition, an oil drain valve should be installed below the inlet and outlet pipe of the valve body 14.

[0038] In addition to the above embodiments, within the scope disclosed in the claims and the specification of the present invention, the technical features or technical data of the present invention can be reselected and combined to form new embodiments, which should also be regarded as specific embodiments of the present invention and within the protection scope of the present invention.

Claims

1. An axial flow check valve for conveying crude oil, comprising a valve body, characterized in that: The valve body includes a horizontally arranged inlet cavity and outlet cavity and a valve cover cavity located at the upper part of the valve body, a valve seat is arranged on the partition wall at the connection between the inlet cavity and the valve cover cavity, a cylindrical sliding valve is arranged in the cylinder at the lower end of the valve cover, the inner hole of the valve cover cylinder is movably matched with the outer circle of the sliding valve, a spring is arranged between the upper spring seat at the lower end of the adjusting screw arranged on the valve cover and the cylinder bottom of the sliding valve, a valve port is formed between the sealing gasket on the lower end surface of the sliding valve and the valve seat, an adjusting sleeve is arranged in the sliding valve, and adjustable flow holes are arranged on the side walls of the sliding valve and the adjusting sleeve.

2. The axial flow check valve for transporting crude oil according to claim 1 is characterized in that: The adjustable flow hole is composed of an outer adjusting hole arranged on the side wall of the sliding valve and an inner adjusting hole arranged on the same height of the side wall of the adjusting sleeve corresponding to the outer adjusting hole. The diameter of the inner adjusting hole is the same as that of the outer adjusting hole.

3. The axial flow check valve for transporting crude oil according to claim 1, characterized in that: The upper end of the adjusting sleeve is provided with a plurality of notches, a pressure plate 1 for fixing the adjusting sleeve is provided above the adjusting sleeve, a thread is provided on the inner wall of the middle section of the sliding valve, the pressure plate 1 is threadedly connected to the inner wall of the sliding valve, and a center hole is provided in the center of the pressure plate 1.

4. The axial flow check valve for transporting crude oil according to claim 1, characterized in that: The lower end surface of the sliding valve is provided with a step surface, and the outer periphery of the lower end surface of the sliding valve is provided with a sealing gasket, the sealing gasket is annular, and the step surface on the inner side of the sealing gasket is provided with a second pressure plate for fixing the sealing gasket, the second pressure plate is fixed to the bottom of the sliding valve by two screws, and the valve port of the check valve is formed between the sealing gasket and the upper end surface of the valve seat.

5. The axial flow check valve for transporting crude oil according to claim 1, characterized in that: An upper spring seat is arranged at the lower end of the adjusting screw, and the upper spring seat is in the shape of a stepped shaft. The central protrusion at the bottom of the sliding valve constitutes a lower spring seat, and the spring is arranged between the upper spring seat and the lower spring seat.

6. The axial flow check valve for transporting crude oil according to claim 1, characterized in that: The center of the valve cover has a cylinder protruding upward, and the center of the cylinder has a stepped hole with a larger diameter at the top and smaller diameter at the bottom. The upper hole is provided with a thread, and the inner wall of the lower hole is provided with a groove. The adjusting screw is screwed into the thread of the upper hole, and an O-ring is provided in the groove of the lower hole.

7. The axial flow check valve for transporting crude oil according to claim 6, characterized in that: The adjusting screw is provided with a tightening nut, the adjusting screw and the tightening nut are provided with a protective cover, the outer periphery of the cylinder of the valve cover is provided with a thread, and the protective cover is screwed on the cylinder of the valve cover.

8. The axial flow check valve for transporting crude oil according to claim 1, characterized in that: The valve cover cavity at the upper part of the valve body is tilted toward one side of the outlet cavity, the center lines of the inlet cavity and the outlet cavity are in the same straight line, and the angle between the center line of the valve cover cavity and the center line of the outlet cavity is 50-60 degrees.

9. The axial flow check valve for transporting crude oil according to claim 1, characterized in that: The valve seat is in a stepped cylindrical shape, and an outward-turned annular surface is provided on the upper edge of the valve seat. The valve port of the check valve is formed between the sealing gasket and the annular surface of the valve seat; the cylinder at the lower end of the valve cover extends to the middle of the valve cover cavity, and an O-ring is provided between the outer wall of the upper section of the cylinder and the inner wall of the upper section of the valve cover cavity.

10. The axial flow check valve for transporting crude oil according to any one of claims 1 to 9, characterized in that: The valve body material is made of sulfur-resistant nickel-based alloy. If the valve body material is cast iron, the non-matching inner surface of the valve body cavity is coated with a sulfur-resistant nickel-based corrosion-resistant alloy layer; the main parts are made of 826 or 316L stainless steel, and the surface of the inner hole of the cylinder at the lower end of the valve cover, the inner and outer surfaces of the sliding valve cylinder, the outer cylindrical surface of the adjusting sleeve and the surface of the valve seat are all coated with a Teflon non-stick layer.

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