Underground mechanical reversing valve device for geothermal well

Abstract

The underground mechanical reversing valve device for the geothermal well comprises a sleeve, the sleeve is a pipeline, and the bottom of the sleeve is sealed; a valve body is arranged in the sleeve; an annular channel is arranged between the valve body and the sleeve; the valve body comprises a positioning body, an outflow cavity, a center valve element and a limiting body from top to bottom. The positioning body is fixed at the top of the outflow cavity, and the positioning body is communicated with the outflow cavity; a sliding groove is formed in the position, below the outflow cavity, in the valve body. The interior of the center valve element is of a hollow structure, and the center valve element is arranged in the sliding groove in a sliding mode. A pressure relief hole is formed in the center of the top of the center valve element, and the center valve element is communicated with the outflow cavity through the pressure relief hole. The underground mechanical reversing valve device for the geothermal well is a mechanical reversing valve, does not need to be powered by a cable, is simple in structure and small in size, and can reliably realize flow direction switching of circulating fluid during heat supply in winter and refrigeration in summer.

Description

Technical Field

[0001] The utility model relates to the technical field of downhole reversing valves, in particular to a downhole mechanical reversing valve device for a geothermal well. Background Art

[0002] As a clean and renewable energy, geothermal energy is increasingly used in the field of heating and cooling. As the main carrier of geothermal energy development and utilization, the requirements of heating and cooling technology of geothermal wells are crucial to the operation of the entire geothermal energy system. In this process, the role of the bottom well reversing valve is particularly prominent, which has a key impact on achieving efficient and stable heating and cooling effects of geothermal wells.

[0003] The coaxial casing underground heat exchange system is one of the important forms of geothermal energy development and utilization at present. For this technology, the combined heat and cold supply mode of taking heat from the formation for heating in winter and releasing heat to the formation for cooling in summer can effectively reduce the attenuation of formation temperature and improve the energy efficiency of system operation. The depth of the coaxial casing geothermal well is generally between 2000m and 3000m. In winter, the circulating water is injected into the wellbore from the annulus. After absorbing heat from the formation, the circulating water enters the central pipe from the bottom of the well and returns to the ground. The ground heat pump system absorbs its heat and re-injects it into the annulus; during cooling in summer, in order to effectively transfer the heat in the circulating fluid to the low-temperature formation and avoid the deep high-temperature formation from transferring heat to the circulating water in reverse, the circulating fluid is generally injected into the wellbore from the central pipe, and flows into the annulus through the downhole reversing valve set at the upper middle position of the central pipe, flows upward in the annulus and transfers heat to the lower temperature formation above.

[0004] Therefore, there is a lack of a downhole reversing valve device with a simple structure, small size, low cost, and the ability to reliably switch the flow direction of the circulating fluid during heating in winter and cooling in summer.

[0005] However, the reversing valves in geothermal well heating and cooling systems in my country are currently mainly electric, and this type of reversing valve has certain problems in actual operation. First, the operation of the electric reversing valve depends on electricity, and in some remote areas, the power supply is unstable, which may cause the reversing valve to fail to work properly. Secondly, the maintenance cost of the electric reversing valve is high, and the failure rate is relatively high, which is not conducive to the stable operation of the geothermal energy system.

[0006] In order to solve these problems, it is particularly necessary to develop a mechanical reversing valve. Mechanical reversing valves are mechanically driven, do not rely on electricity, and have strong adaptability and reliability. In the application of bottom well reversing valves, mechanical reversing valves can better adapt to the complex environment of geothermal wells and ensure the stable operation of heating and cooling systems. In addition, mechanical reversing valves have low maintenance costs and relatively low failure rates, which is conducive to improving the operating efficiency of geothermal energy systems.

[0007] Therefore, an underground mechanical reversing valve device for geothermal wells is designed to solve the above problems. Summary of the invention

[0008] In order to overcome the above shortcomings, the utility model provides a downhole mechanical reversing valve device for geothermal wells, comprising a casing, the casing is a pipeline and the bottom is sealed; a valve body is arranged in the casing; an annular channel is arranged between the valve body and the casing;

[0009] The valve body comprises a positioning body, an outflow cavity, a central valve core, and a limiter from top to bottom;

[0010] The positioning body is fixed on the top of the outflow cavity, and the positioning body is connected to the outflow cavity; a sliding groove is arranged in the valve body below the outflow cavity; the interior of the central valve core is a hollow structure and is slidably arranged in the sliding groove; a pressure relief hole is arranged at the center of the top of the central valve core, and the central valve core is connected to the outflow cavity through the pressure relief hole; a plurality of outflow holes are arranged around the outer circumference of the central valve core; the outflow hole is connected to the sliding groove and the central valve core; a side liquid outlet hole is arranged on the outer circumference of the valve body, and the side liquid outlet hole connects the sleeve with the sliding groove;

[0011] A spring is fixed on the bottom surface of the central valve core, and a spring stabilizer is passed through the middle of the spring; a plurality of holes penetrating from top to bottom are opened on the limit body, the limit body is fixedly arranged at the lower part of the sliding groove and cooperates with the spring stabilizer through the center hole, the spring stabilizer cooperates with the limit body, and the spring stabilizer also supports the spring.

[0012] Furthermore, 3 to 6 outflow holes are provided.

[0013] Furthermore, 2 to 4 side liquid outlet holes are provided.

[0014] Furthermore, the magnitude of the switching pressure and flow rate of the valve body can be adjusted by adjusting the modulus of the spring and the through-slot structure on the positioning body.

[0015] Furthermore, the valve body is made of rust-proof metal.

[0016] Furthermore, the diameter of the pressure relief hole is 15 mm.

[0017] The beneficial effects of the utility model are:

[0018] The utility model discloses an underground mechanical reversing valve device for geothermal wells, which is a mechanical reversing valve, does not require power supply by cables, has a simple structure and a small size, and can reliably realize the switching of the flow direction of the circulating fluid during heating in winter and cooling in summer.

[0019] Compared with the traditional four-way solenoid valve, it has the following advantages:

[0020] (1) No cable power supply is required, and the device uses the pressure difference of the circulating fluid itself to switch direction, reducing installation and maintenance costs. Due to the mechanical structure, the reversing valve can be driven directly by the wellhead equipment, avoiding the trouble caused by cable power supply and reducing the interference of environmental factors;

[0021] (2) Strong resistance to environmental interference. Mechanical reversing valves are not affected by electromagnetic interference, temperature changes and other factors, do not require complex electronic control systems, have simple and compact structures, are easy to manufacture and maintain, and can work stably in harsh environments;

[0022] (3) Easy operation and high reliability. By adjusting the elastic force of the spring and the through-slot structure on the positioning body, the switching pressure and flow rate of the device can be easily adjusted to meet the needs of different application scenarios. Failures are less likely to occur during operation, which improves energy utilization.

[0023] (4) Strong adaptability. The reversing valve can be applied to various geothermal, geocooling and other new energy projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the valve body in a static state;

[0025] Figure 2 It is a schematic diagram of the structure of the utility model in a static state (in a static state);

[0026] Figure 3 This is a schematic diagram of the utility model in summer cooling state (side liquid outlet hole covered state)

[0027] Figure 4 This is a schematic diagram of summer cooling of the utility model;

[0028] Figure 5 This is a schematic diagram of the utility model in winter heating state (the side liquid outlet hole is exposed)

[0029] Figure 6 This is a schematic diagram of winter heating of the utility model;

[0030] Figure 7 This is a schematic diagram of the internal structure of the utility model;

[0031] Figure 8 This is a schematic diagram of the internal structure of the utility model (including the casing);

[0032] Fig. 9 A three-dimensional diagram of the center valve core;

[0033] Fig.10 It is a three-dimensional diagram of a spring, a limiter and a spring stabilizer;

[0034] Fig.11 is a stereogram of the limiting body;

[0035] in:

[0036] 1-positioning body; 2-flow cavity; 3-pressure relief hole; 4-flow hole; 5-center valve core; 6-side liquid outlet hole; 7-spring; 8-limiting body; 9-spring stabilizer; 10-sleeve; DETAILED DESCRIPTION

[0037] like Figure 1 , Figure 7 and Figure 8 As shown, a downhole mechanical reversing valve device for a geothermal well includes a casing 10, the casing 10 is a pipeline with a bottom seal; a valve body is arranged in the casing 10; an annular channel is arranged between the valve body and the casing 10;

[0038] The valve body comprises, from top to bottom, a positioning body 1, an outflow cavity 2, a central valve core 5, and a limiting body 8;

[0039] like Figure 6 As shown, the positioning body 1 is fixed on the top of the outflow cavity 2, and the positioning body 1 is connected to the outflow cavity 2; a sliding groove is arranged in the valve body below the outflow cavity 2; the interior of the central valve core 5 is a hollow structure and is slidably arranged in the sliding groove; a pressure relief hole 3 is arranged at the center of the top of the central valve core 5, and the central valve core 5 is connected to the outflow cavity 2 through the pressure relief hole 3; a plurality of outflow holes 4 are arranged around the outer circumference of the central valve core 5; the outflow holes 4 are connected to the sliding groove and the central valve core 5; a side liquid outlet hole 6 is arranged on the outer circumference of the valve body, and the side liquid outlet hole 6 connects the sleeve 10 with the sliding groove;

[0040] The design of the outlet hole 4 and the outlet cavity 2 allows the fluid to flow out smoothly from the interior of the central valve core 5 and be evenly distributed along the circumference, thereby ensuring the uniformity and stability of the fluid and effectively improving the working efficiency of the reversing valve;

[0041] The bottom surface of the central valve core 5 is fixed with a spring 7, and a spring stabilizer 9 is provided in the middle of the spring 7; Figure 7 As shown, the limiting body 8 is provided with a plurality of holes which penetrate from top to bottom. The limiting body 8 is fixedly arranged at the lower part of the sliding groove and cooperates with the spring stabilizer 9 through the center hole. The spring stabilizer 9 cooperates with the limiting body 8 and the spring stabilizer 9 also supports the spring 7.

[0042] The limiting body 8 is fixedly arranged at the lower part of the sliding groove and cooperates with the spring stabilizer 9 through the hole, so that the central valve core 5 and the spring 7 will not be offset during the movement and compression process.

[0043] The number of the outlet holes 4 is 3 to 6. The number of the side outlet holes 6 is 2 to 4. The valve body is made of rust-proof metal.

[0044] In order to reduce the instantaneous high pressure generated when the fluid is injected, thereby reducing the water hammer effect, the diameter of the pressure relief hole 3 is 15 mm.

[0045] The size of the switching pressure and flow rate of the valve body can be adjusted by adjusting the modulus of the spring and the through-slot structure on the positioning body.

[0046] Usage and principle:

[0047] like Figure 1 In the static state shown, the bottom hole mechanical reversing valve uses the pressure difference of the circulating fluid itself to perform reversing, and there is no need to pass a cable to the bottom hole for power supply. In the static state where the fluid is not flowing, the valve core 5 falls onto the bottom spring under the action of gravity, and the valve core outlet hole 4 and the side outlet hole 6 are both in a blocked state;

[0048] like Figure 3 and Figure 4 As shown, in summer cooling, the fluid flows downward from the central tube and enters through the positioning body 1 on the upper part of the valve body. The fluid pressure acts on the central valve core 5, pushing the central valve core 5 downward until the side outlet hole 6 is fully opened. At this time, the fluid flows out through the side outlet hole 6 and enters the annular channel in the casing 10 and moves upward, and transfers its internal heat to the formation.

[0049] like Figure 5 and Figure 6 As shown, during winter heating, the fluid flows from the environmental control to the underground and absorbs heat from the formation. After reaching the bottom of the well, it enters the central pipe and goes upward, and then flows in from the hole arranged on the limit body 8 at the bottom of the valve body. Under the action of the fluid pressure, the central valve core 5 moves upward. As the central valve core 5 rises, the fluid flows into the outflow cavity through the outflow hole, and flows out through the through groove on the positioning body, realizing the reversing function.

[0050] like Figure 7 and Figure 8As shown, the internal structure of the bottom hole mechanical reversing valve provided by the utility model is clearly visible. The outflow cavity 2 is located at the upper part of the valve body, and its internal space is connected with the positioning body 1. The central valve core 5 is arranged in a sliding manner in the slide groove, and is supported and limited by the spring 7 and the spring stabilizer 9, so that it can move up and down under different pressures. When cooling in summer, the fluid flows downward from the central tube. When the fluid pressure acts on the upper surface of the central valve core 5, the valve core 5 will move downward and compress the spring until the side liquid outlet 6 is fully opened, and the fluid flows out through the side liquid outlet 6. When heating in winter, the circulating fluid descends from the annulus and enters the central tube from the bottom of the well and ascends. When the upward fluid enters the central valve core 5, under the action of the fluid pressure, the central valve core 5 will move upward until it contacts the positioning body 1. At this time, the fluid enters the outflow cavity 2 through the outflow hole 4 and flows out through the positioning body 1, realizing the reversal of the fluid.

[0051] The positioning body 1, the outflow cavity 2, the central valve core 5, the spring 7 and the limiter 8 and other components are precisely matched to form this efficient reversing valve device. In practical applications, the reversing pressure and flow of the device can be easily adjusted to adapt to various application scenarios by simply adjusting the modulus of the spring and the through-slot structure on the positioning body according to specific needs.

[0052] like Fig. 9 , Fig.10 and Fig.11 As shown, the three-dimensional schematic diagrams of the central valve core 5, the spring 7, the limiter 8 and the limiter 8 are respectively shown. The hollow structure of the central valve core 5 and the design of the outflow hole 4 on the outside allow the fluid to flow smoothly when the valve core moves. The hole design on the limiter 8 allows the fluid to flow in from the bottom during winter heating, driving the valve core to move upward to achieve the reversing function.

[0053] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0054] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0055] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A downhole mechanical reversing valve device for a geothermal well, comprising a casing (10), wherein the casing (10) is a pipeline and has a bottom seal; a valve body is arranged in the casing (10); characterized in that: An annular channel is provided between the valve body and the sleeve (10); The valve body comprises, from top to bottom, a positioning body (1), an outflow cavity (2), a central valve core (5), and a limiting body (8); The positioning body (1) is fixed on the top of the outflow cavity (2), and the positioning body (1) and the outflow cavity (2) are connected; a sliding groove is arranged in the valve body below the outflow cavity (2); the interior of the central valve core (5) is a hollow structure and is slidably arranged in the sliding groove; a pressure relief hole (3) is arranged in the center of the top of the central valve core (5), and the central valve core (5) is connected to the outflow cavity (2) through the pressure relief hole (3); a plurality of outflow holes (4) are arranged around the outer circumference of the central valve core (5); the outflow holes (4) are connected to the sliding groove and the central valve core (5); a side liquid outlet hole (6) is arranged on the inner circumference of the valve body, and the side liquid outlet hole (6) connects the sleeve (10) with the sliding groove; A spring (7) is fixed on the bottom surface of the central valve core (5), and a spring stabilizer (9) is inserted in the middle of the spring (7); a plurality of holes extending vertically through the limiter (8) are provided on the limiter (8); the limiter (8) is fixedly arranged at the bottom of the sliding groove and cooperates with the spring stabilizer (9) through the central hole; the spring stabilizer (9) cooperates with the limiter (8), and the spring stabilizer (9) also supports the spring (7).

2. A downhole mechanical reversing valve device for a geothermal well according to claim 1, characterized in that: The number of the outflow holes (4) is 3 to 6.

3. A downhole mechanical reversing valve device for a geothermal well according to claim 2, characterized in that: The side liquid outlet holes (6) are provided in 2 to 4 numbers.

4. A downhole mechanical reversing valve device for a geothermal well according to claim 3, characterized in that: The size of the switching pressure and flow rate of the valve body can be adjusted by adjusting the modulus of the spring and the through-slot structure on the positioning body.

5. A downhole mechanical reversing valve device for geothermal wells according to claim 4, characterized in that: The valve body is made of rust-proof metal.

6. A downhole mechanical reversing valve device for a geothermal well according to claim 5, characterized in that: The diameter of the pressure relief hole (3) is 15 mm.

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