Water injection pressure maintaining device and using method thereof

Abstract

The invention discloses a water injection pressure maintaining device and a using method thereof, and relates to the field of water injection pressure maintaining devices, and the technical scheme is characterized in that the water injection pressure maintaining device comprises a liquid inlet connected with liquid injection pump equipment, a liquid outlet connected with a water injection cavity, a pressure measuring port connected with a pressure gauge and an overflow port; a one-way valve seat, a liquid inlet one-way valve, a liquid outlet five-way valve and a pressure regulating valve are sequentially arranged between the liquid inlet and the liquid outlet, and the pressure maintaining and stabilizing device can safely and reliably carry out a water injection cavity pressure test experiment and a water injection cavity pressure bearing and withstanding value test so as to well complete corresponding work and can be used for a test experiment after water injection of a drill hole lower sleeve; on the premise of pressure maintaining, the fracture water injection state is checked, the pressure-bearing and pressure-resisting value of the water injection cavity is tested, in a drilling pressure-resisting experiment, the water injection pressure maintaining device can accurately control and keep the pressure stable, and test data can accurately reflect the pressure-resisting condition of a test object.

Description

Technical Field

[0001] The present invention relates to the field of water injection pressure maintaining devices, and more specifically, to a water injection pressure maintaining device and a use method thereof. Background Art

[0002] With the advancement of technology, water injection equipment has developed rapidly, and equipment that directly uses high-pressure water to do work has emerged in large numbers and is widely used. For example, coal seam water injection pumps use high-pressure water as a direct power source to do work in coal mining. By injecting water into the coal seam, it improves the permeability of the coal seam, reduces the gas content, and ensures mining safety and efficiency.

[0003] During its operation, it is often necessary to frequently check the water injection status and test the pressure resistance value of the water injection chamber. However, due to the lack of water injection and pressure maintaining devices, many problems are faced in actual operation. On the one hand, it is impossible to find out the water injection status, so it is difficult to judge whether the water injection is uniform and whether it has achieved the expected effect; on the other hand, the pressure resistance value fluctuates too much, making accurate testing difficult to achieve, and it is impossible to obtain reliable data for evaluating equipment performance and coal seam conditions. Moreover, the unstable pressure leads to excessive impact vibration, which is extremely dangerous to the experimental process, may damage the experimental equipment, and also pose a threat to the safety of operators. This makes it difficult for users to control the actual water injection operation. In the absence of a water injection and pressure maintaining device, the experimental work lacks reference value due to inaccurate data, and is very dangerous due to safety hazards.

[0004] Therefore, in order to solve the above technical problems, the present application proposes a water injection and pressure maintaining device and a method for using the same. Summary of the invention

[0005] In view of the deficiencies in the prior art, an object of the present invention is to provide a water injection and pressure maintaining device and a method of using the same.

[0006] To achieve the above object, the present invention provides the following technical solution: a water injection pressure maintaining device, comprising a liquid inlet connected to a liquid injection pump device, a liquid outlet connected to a water injection chamber, a pressure measuring port connected to a pressure gauge, and an overflow port, wherein the following are arranged in sequence between the liquid inlet and the liquid outlet: A one-way valve seat connected to the liquid inlet via an adapter A; The liquid inlet check valve is used to control the one-way flow of liquid, allowing high-pressure water to enter the subsequent components of the device during the water injection process and preventing liquid backflow during the pressure maintenance stage to achieve the pressure maintenance function; Liquid outlet five-way, used for distributing and guiding liquid; The pressure regulating valve guides the water flow into the pressure regulating valve through the liquid outlet five-way. The pressure measuring port and the overflow port are arranged on the pressure regulating valve. When the pressure in the device exceeds the safety upper limit, the pressure regulating valve opens to allow water to overflow through the overflow port, thereby regulating and stabilizing the pressure in the device. The liquid outlet end of the pressure regulating valve is connected to the liquid outlet through an adapter B.

[0007] Preferably, the liquid outlet five-way valve and the one-way valve seat are connected to the boost anti-shake device through a transition joint.

[0008] Preferably, the liquid inlet one-way valve comprises a one-way valve body A, a one-way valve core and a one-way valve body B which are connected in sequence, and a tower-shaped spring is installed between the one-way valve core and the one-way valve body B.

[0009] Preferably, a metal spherical seal is formed between the one-way valve body B and the one-way valve core.

[0010] Preferably, the liquid inlet one-way valve is sealed by an O-ring and an inner conical surface of a one-way valve seat.

[0011] Preferably, the liquid inlet is connected to the water injection pump equipment through a hose, and the connection method adopts a mining KJ-type quick-plug connector, which is quickly plugged in and then the U-shaped pin is installed.

[0012] Preferably, the pressure regulating valve comprises a pressure regulating stud, a regulating spring, a regulating valve core A, a steel ball A, a regulating valve body, a regulating valve core B and a steel ball B, and the pressure regulating valve is realized by rotating the pressure regulating stud thereon.

[0013] Preferably, the pressure adjusting stud and the regulating valve body are assembled with a right-hand thread, and the adjusting spring is arranged on the pressure adjusting stud. By rotating the pressure adjusting stud, the preload force of the adjusting spring is changed, thereby changing the force acting on the regulating valve core A, steel ball A, regulating valve core B, and steel ball B.

[0014] The method of using the water injection pressure maintaining device comprises the following steps: Step 1: Use a hose to connect the liquid inlet of the water injection pressure maintaining device to the water injection pump equipment through a mining KJ-type quick-connect connector, and install a U-shaped pin to ensure that the connection is firm and well sealed. Connect the liquid outlet to the water injection chamber, the pressure measuring port to the pressure gauge, and the overflow port to a suitable liquid collection device; Step 2: Connect and install the adapter A, one-way valve seat, liquid inlet one-way valve, transition joint, liquid outlet five-way, pressure regulating valve, adapter B and other components in sequence according to the design requirements to ensure that the connections between the components are tight and accurate; Step 3: Turn on the water injection pump equipment, and high-pressure water flows in from the liquid inlet, passes through the adapter A and enters the one-way valve seat. When the high-pressure water pressure reaches a certain value, it overcomes the elastic force of the tower spring and pushes open the one-way valve core of the liquid inlet one-way valve. The high-pressure water enters the boost and anti-shake device through the small hole on the one-way valve body B for boost and anti-shake treatment. Then, the high-pressure water flows into the liquid outlet five-way through the transition joint; Step 4: During the water injection process, monitor the pressure in the device in real time by observing the pressure gauge connected to the pressure measuring port. According to the experimental requirements, rotate the pressure regulating stud of the pressure regulating valve to adjust the upper limit of the overflow pressure. When the pressure in the device is normal, high-pressure water flows into the water injection chamber from the liquid outlet through the liquid outlet five-way and adapter B. When the pressure exceeds the safety upper limit, the pressure regulating valve opens, and the liquid is discharged through the overflow port to reduce the pressure in the device. During the water injection chamber pressure test experiment and the pressure resistance value test, if the water injection chamber pressure is higher than the liquid inlet pressure, the high-pressure water at the rear end of the liquid inlet check valve will flow back, pushing the check valve core to close, and realizing the pressure holding function; Step 5: After the experiment, turn off the water injection pump first, then disassemble the connecting parts according to the correct operating sequence, and clean and maintain the water injection and pressure maintaining device.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The pressure-maintaining and stabilizing device of the present invention can safely and reliably perform water injection chamber pressure test experiments and water injection chamber pressure bearing and withstand value tests to complete corresponding work well. It can be used for test experiments after casing water injection in a borehole, to check the water injection state of the fracture and test the pressure bearing and withstand value of the water injection chamber under the premise of maintaining pressure. In the borehole pressure withstand test, the water injection pressure-maintaining device can accurately control and maintain the pressure stable, so that the test data can accurately reflect the pressure withstand condition of the test object, so as to solve the problem in the background technology that in the absence of a water injection pressure-maintaining device, the experimental work lacks reference value due to inaccurate data and is very dangerous due to potential safety hazards; 2. The liquid inlet check valve of the present invention realizes sealing through the O-type sealing ring and the inner conical surface of the check valve seat. The contact mode between the inner conical surface of the check valve seat and the O-type sealing ring can make the sealing pressure evenly distributed on the contact surface. Compared with some other sealing methods, this uniform pressure distribution can better adapt to pressure changes in different directions and sizes. During the operation of the device, no matter how the liquid pressure fluctuates, it can maintain stable sealing performance and reduce the possibility of leakage; 3. In the present invention, the liquid outlet five-way valve and the one-way valve seat are connected to the boost anti-shake device through a transition joint. The boost anti-shake device can effectively absorb and buffer the impact force of the water flow, reduce the vibration caused by the impact of the water flow, and reduce the impact of the vibration on the entire water injection system and the experimental process, so that the equipment can run more smoothly. At the same time, by reducing vibration, it can reduce the wear and damage to the equipment parts and components, extend the service life of the equipment, and also reduce the problems of loose pipes and damage to connectors caused by vibration, thereby improving the stability and safety of the entire system and ensuring the smooth progress of experiments or operations; 4. A metal spherical seal is provided between the one-way valve body B and the one-way valve core of the present invention. The metal spherical seal can utilize the close fit between the spherical surface and the corresponding surface to form a higher sealing pressure ratio on a smaller contact area, thereby effectively preventing the leakage of liquid or gas. Even under complex working conditions such as high pressure and high flow, a good sealing effect can be maintained to ensure that the medium flows along the prescribed path. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 It is a schematic diagram of the specific structure of the present invention; Figure 2 For the present invention Figure 1 Bottom view of Figure 3 For the present invention Figure 1 A local structure enlarged view; Figure 4 It is a schematic diagram of the specific structure of the pressure regulating valve in the present invention; Figure 5 is an overall diagram of the device of the present invention; Figure 6 For the present invention Figure 5 Side view of Figure 7 For the present invention Figure 5 Top view of the .

[0017] In the figure: 1. Liquid inlet; 2. Liquid outlet; 3. Pressure measuring port; 4. Overflow port; 5. Check valve seat; 6. Adapter A; 7. Liquid inlet check valve; 701. Check valve body A; 702. Check valve core; 703. Check valve body B; 704. Tower spring; 8. Liquid discharge five-way; 9. Pressure regulating valve; 901. Pressure regulating stud; 902. Adjusting spring; 903. Adjusting valve core A; 904. Steel ball A; 905. Adjusting valve body; 906. Adjusting valve core B; 907. Steel ball B; 908. Adjusting valve seat; 10. Adapter B; 11. Transition joint; 12. Pressure booster stabilizer; 13. O-ring. DETAILED DESCRIPTION

[0018] Example 1 like Figure 1 , Figure 2 , Figure 5 as well as Figure 7 As shown, the present invention provides a water injection pressure maintaining device, comprising a liquid inlet 1 connected to a liquid injection pump device, a liquid outlet 2 connected to a water injection chamber, a pressure measuring port 3 connected to a pressure gauge, and an overflow port 4, and the following are arranged in sequence between the liquid inlet 1 and the liquid outlet 2: A one-way valve seat 5, which is connected to the liquid inlet 1 via an adapter A6; The liquid inlet check valve 7 is used to control the one-way flow of the liquid, allowing high-pressure water to enter the subsequent components of the device during the water injection process and preventing the liquid from flowing back during the pressure maintenance stage to achieve the pressure maintenance function; Liquid outlet five-way 8, used for distributing and guiding the liquid; The pressure regulating valve 9 is provided with a liquid outlet five-way 8 to guide the water flow into the pressure regulating valve 9. The pressure measuring port 3 and the overflow port 4 are arranged on the pressure regulating valve 9. The liquid outlet end of the pressure regulating valve 9 is connected to the liquid outlet 2 via an adapter B10.

[0019] When in use, adjust the pressure regulating valve 9 to a suitable pressure, then input high-pressure water from the liquid inlet 1 into the water injection pressure maintaining device through the liquid injection pump equipment, and the high-pressure water flows through the adapter A6 and enters the one-way valve seat 5. At this time, the pressure of the high-pressure water acts on the liquid inlet one-way valve 7. When the pressure reaches a certain value, the liquid inlet one-way valve 7 will be pushed open by the pressure, so that the high-pressure water flows into the liquid outlet five-way 8. The liquid outlet five-way 8 serves as a diversion and confluence component, directing part of the high-pressure water to the pressure regulating valve 9, and the other part is ready to merge with the high-pressure water adjusted by the pressure regulating valve 9. Finally, the high-pressure water flows into the water injection chamber through the adapter B10 via the liquid outlet 2. During the water injection chamber pressure test experiment and the pressure resistance value test, if the water injection chamber pressure is higher than the liquid inlet 1 pressure, the high-pressure water at the rear end of the liquid inlet one-way valve 7 will flow back. The refluxed high-pressure water generates a strong thrust, which can close the liquid inlet check valve 7, prevent the liquid from reflux, and realize the pressure-maintaining function. During the water injection process, the pressure in the device is monitored in real time by observing the pressure gauge connected to the pressure measuring port 3 (so as to understand the water injection status). The pressure is adjusted by the regulating valve according to the experimental requirements. The pressure regulating valve 9 is opened when the pressure in the device exceeds the safety upper limit, so that the water overflows through the overflow port 4, thereby adjusting and stabilizing the pressure in the device. Therefore, the pressure-maintaining device can safely and reliably carry out the water injection chamber pressure test experiment and the pressure-maintaining and pressure-stabilizing device for the water injection chamber pressure bearing and pressure resistance value test to complete the corresponding work well. It can be used for the test experiment after the casing is injected into the borehole, and the water injection status of the fracture and the pressure-bearing and pressure resistance value of the water injection chamber are checked under the premise of pressure maintenance. In the borehole pressure resistance test, the water injection pressure-maintaining device can accurately control and maintain the pressure stable, so that the test data can accurately reflect the pressure resistance of the test object. At the same time, it can also protect the experimental equipment and the test object, avoid the damage caused by the impact vibration of the sudden change of pressure, and ensure the safe and stable development of the experiment. It has the advantages of reliable pressure maintenance, stable outlet pressure and small impact vibration.

[0020] It should be noted that the liquid outlet five-way 8 is a multi-channel connection component. On the one hand, it guides part of the liquid to the pressure regulating valve 9 so as to perform pressure regulation and overflow operation when the pressure exceeds the safety upper limit; on the other hand, it merges another part of the liquid (when the pressure is normal) with the liquid regulated by the pressure regulating valve 9 and guides it to the liquid outlet 2 through the adapter B10, so that the liquid can smoothly flow out of the device and enter the water injection chamber. The liquid outlet five-way 8 plays a key role in the device to reasonably distribute the flow direction of the liquid, ensuring that the liquid can flow according to different working conditions and needs.

[0021] Furthermore, the liquid inlet check valve 7 is sealed with the inner cone of the check valve seat 5 through the O-ring 13, and the contact between the inner cone of the check valve seat 5 and the O-ring 13 can make the sealing pressure evenly distributed on the contact surface. Compared with some other sealing methods, this uniform pressure distribution can better adapt to pressure changes in different directions and sizes. During the operation of the device, no matter how the liquid pressure fluctuates, it can maintain stable sealing performance and reduce the possibility of leakage. The liquid outlet five-way 8 and the check valve seat 5 are connected to the boost anti-shake device 12 through the transition joint 11. The functions of the boost anti-shake device 12 are as follows: Boosting pressure: The booster anti-shake device 12 can boost the pressure of the water flow entering the device to ensure that the water injection chamber can obtain a sufficiently high pressure.

[0022] Stable pressure output: It can make the pressure output more stable, ensuring that the pressure will not fluctuate greatly during the water injection process, providing a stable pressure basis for subsequent water injection and pressure maintenance operations, which is conducive to improving the accuracy and reliability of experimental data, and also helps to protect the equipment and avoid damage to the equipment due to fluctuations in pressure.

[0023] Reduce impact vibration: During the flow of high-pressure water, the booster anti-shake device can effectively absorb and buffer the impact force of the water flow, reduce the vibration caused by the impact of the water flow, and reduce the impact of vibration on the entire water injection system and the experimental process, making the equipment run more smoothly. At the same time, by reducing vibration, it can reduce the wear and damage to equipment parts and components, extend the service life of the equipment, and also reduce problems such as loose pipes and damaged connectors caused by vibration, thereby improving the stability and safety of the entire system and ensuring the smooth progress of experiments or operations.

[0024] In addition, the liquid inlet 1 is connected to the water injection pump equipment through a hose, and the connection method adopts a mining KJ type quick-plug connector, which is quickly inserted and then installed with a U-shaped pin. The design of the mining KJ type quick-plug connector makes the connection between the liquid inlet 1 and the water injection pump equipment only need to quickly insert the connector to complete the initial connection, without the need for complex thread screwing or bolt tightening operations like the traditional connection method, which greatly saves installation time and improves work efficiency. In the case of emergency installation or rapid commissioning of equipment, the advantages of this quick connection are particularly obvious. When the equipment needs to be maintained, repaired or replaced, the disassembly process is also simple and fast. Simply pull out the U-shaped pin to easily separate the quick-plug connector, which is convenient for further operation of the equipment and reduces the time cost and labor cost of equipment maintenance. At the same time, the mining KJ type quick-plug connector usually has a good sealing structure, which can ensure the sealing of the connection part while quickly connecting, and effectively prevent high-pressure water from leaking during the water injection process. This is crucial to maintaining the pressure stability and water injection efficiency of the water injection system, avoiding pressure loss and water resource waste caused by water leakage.

[0025] Moreover, the one-way valve body B703 and the one-way valve core 702 are sealed with a metal spherical surface, and the liquid inlet one-way valve 7 is sealed by the O-ring 13 and the inner cone of the one-way valve seat 5. The O-ring 13 has good elasticity and flexibility. During the installation process, when the liquid inlet one-way valve 7 is matched with the inner cone of the one-way valve seat 5, the O-ring 13 can be squeezed and deformed, thereby tightly filling the small gap between the two, preventing the liquid from leaking from the gap, ensuring the reliability of the seal, ensuring that the liquid in the water injection pressure-maintaining device flows in the specified direction, and preventing backflow. The contact between the inner cone and the O-ring 13 can make the sealing pressure evenly distributed on the contact surface. Compared with some other sealing methods, this uniform pressure distribution can better adapt to pressure changes in different directions and sizes. During the operation of the device, no matter how the liquid pressure fluctuates, it can maintain stable sealing performance and reduce the possibility of leakage.

[0026] Example 2 like Figures 1 to 6 As shown, this embodiment is a specific structure of the liquid inlet one-way valve 7 and the pressure regulating valve 9 in Embodiment 1.

[0027] The liquid inlet check valve 7 comprises a check valve body A701, a check valve core 702 and a check valve body B703 which are connected in sequence, and a tower-shaped spring 704 is installed between the check valve core 702 and the check valve body B703.

[0028] Opening process: When high-pressure water flows in from the liquid inlet 1, passes through the adapter A6 and the one-way valve seat 5 and enters the one-way valve body A701, the water pressure gradually increases. When the water pressure reaches a certain value, it can overcome the elastic force of the tower spring 704 and push open the one-way valve core 702 of the liquid inlet one-way valve 7. At this time, the high-pressure water enters the boost anti-shake device 12 through the small hole on the one-way valve body B703, allowing the liquid to continue to flow in the device.

[0029] Pressure holding process: During the water injection chamber pressure test experiment and the water injection chamber pressure resistance test, if the pressure of the water injection chamber is higher than the pressure on the side of the liquid inlet 1, the high-pressure water (liquid) at the rear end of the liquid inlet check valve 7 will flow back. The impact force generated by the refluxed high-pressure water (liquid) will instantly push the check valve core 702 to move, making it fit tightly with the check valve body A701, closing the liquid inlet check valve 7 to prevent the liquid from flowing back, thereby achieving the pressure holding function.

[0030] Furthermore, there is a metal spherical seal between the one-way valve body B703 and the one-way valve core 702. The metal spherical seal can utilize the close fit between the spherical surface and the corresponding surface to form a higher sealing pressure ratio on a smaller contact area, thereby effectively preventing the leakage of liquid or gas. Even under complex working conditions such as high pressure and high flow, it can maintain a good sealing effect to ensure that the medium flows along the prescribed path. At the same time, the geometric shape of the spherical surface enables it to automatically adjust the contact state with the mating surface within a certain range when it is under pressure, compensate for the changes in the sealing gap caused by manufacturing errors, installation deviations or component deformation, and always maintain good sealing performance.

[0031] The pressure regulating valve 9 has a regulating valve seat 908, which also includes a pressure regulating stud 901, an regulating spring 902, a regulating valve core A903, a steel ball A904, a regulating valve body 905, a regulating valve core B906 and a steel ball B907. The pressure regulating valve 9 is realized by rotating the pressure regulating stud 901 thereon. The pressure regulating stud 901 and the regulating valve body 905 are assembled with a right-hand thread. The regulating spring 902 is arranged on the pressure regulating stud 901. By rotating the pressure regulating stud 901, the preload force of the regulating spring 902 is changed, thereby changing the force acting on the regulating valve core A903, the steel ball A904, the regulating valve core B906 and the steel ball B907.

[0032] Pressure regulation: The upper limit of the overflow pressure can be adjusted by rotating the pressure adjustment screw 901. When the pressure adjustment screw 901 is rotated clockwise, the pressure adjustment screw 901 will be screwed into the regulating valve body 905, compressing the regulating spring 902, so that the preload force of the regulating spring 902 increases. After the preload force of the regulating spring 902 increases, the force acting on the regulating valve core A903, the steel ball A904, the regulating valve core B906, and the steel ball B907 will increase, so that the steel ball B907 needs a higher pressure to be pushed open, that is, the opening pressure of the steel ball B907 increases, thereby increasing the upper limit of the overflow pressure. On the contrary, when the pressure regulating stud 901 is rotated counterclockwise, the pressure regulating stud 901 will be screwed outward, the preload force of the regulating spring 902 will decrease, and the force acting on the regulating valve core A903, the steel ball A904, the regulating valve core B906, and the steel ball B907 will also decrease. The opening pressure of the steel ball B907 will decrease, and the upper limit of the overflow pressure will be reduced.

[0033] Overflow process: When the pressure in the water injection and pressure maintaining device gradually increases and reaches or exceeds the safety upper limit, under the coordinated action of the adjusting spring 902, the adjusting valve core A903, the steel ball A904, the adjusting valve core B906, the steel ball B907 and other components, the pressure regulating valve 9 opens, and the water (liquid) overflows through the overflow port 4, thereby reducing the pressure in the device and protecting the experimental equipment and the test object from damage caused by excessive pressure.

[0034] The main features of this water injection and pressure maintenance device are: 1. Precisely control and maintain stable pressure; 2. Allow test data to accurately reflect the pressure resistance of the test object; 3. Protect experimental equipment and test objects; 4. Avoid damage caused by shock and vibration caused by sudden changes in pressure; 5. Ensure the safe and stable conduct of the experiment.

[0035] The present invention also provides a method for using the water injection and pressure maintaining device: Step 1: Use a hose to connect the liquid inlet 1 of the water injection pressure maintaining device to the water injection pump equipment through a mining KJ-type quick-connect connector, and install a U-shaped pin to ensure that the connection is firm and well sealed. Connect the liquid outlet 2 to the water injection chamber, the pressure measuring port 3 to the pressure gauge, and the overflow port 4 to a suitable liquid collection device; Step 2: Connect and install the adapter A6, check valve seat 5, liquid inlet check valve 7, transition joint 11, liquid outlet five-way 8, pressure regulating valve 9, adapter B10 and other components in sequence according to the design requirements, and ensure that the connection between the components is tight and accurate; Step 3: Turn on the water injection pump equipment, and high-pressure water flows in from the liquid inlet, passes through the adapter A6 and enters the one-way valve seat 5. When the high-pressure water pressure reaches a certain value, it overcomes the elastic force of the tower-shaped spring 704, pushes open the one-way valve core 702 of the liquid inlet one-way valve 7, and the high-pressure water enters the booster anti-shake device 12 through the small hole on the one-way valve body B703, and is pressurized and anti-shake processed. Then, the high-pressure water flows into the liquid outlet five-way 8 through the transition joint 11; Step 4: During the water injection process, the pressure in the device is monitored in real time by observing the pressure gauge connected to the pressure measuring port 3. According to the experimental requirements, the pressure regulating stud 901 of the pressure regulating valve 9 is rotated to adjust the upper limit of the overflow pressure. When the pressure in the device is normal, high-pressure water flows into the water injection chamber from the liquid outlet through the liquid outlet five-way 8 and the adapter B10. When the pressure exceeds the safety upper limit, the pressure regulating valve 9 is opened, and the liquid is discharged through the overflow port 4 to reduce the pressure in the device. During the water injection chamber pressure test experiment and the pressure resistance value test, if the water injection chamber pressure is higher than the pressure of the liquid inlet 1, the high-pressure water at the rear end of the liquid inlet check valve 7 flows back, pushing the check valve core 702 to close, and realizing the pressure maintaining function; Step 5: After the experiment, turn off the water injection pump first, then disassemble the connecting parts according to the correct operating sequence, and clean and maintain the water injection and pressure maintaining device.

[0036] The water injection and pressure maintaining device of the present invention and the use method thereof have the following advantages: The pressure-maintaining and stabilizing device can safely and reliably carry out the water injection chamber pressure test experiment and the water injection chamber pressure resistance value test to complete the corresponding work well. It can be used for the test experiment after the casing is put into the borehole for water injection. Under the premise of maintaining pressure, the water injection state of the fracture and the pressure resistance value of the water injection chamber can be checked. In the borehole pressure resistance test, the water injection pressure-maintaining device can accurately control and maintain the pressure stable, so that the test data can accurately reflect the pressure resistance of the test object; The liquid inlet check valve 7 is sealed by the O-ring 13 and the inner conical surface of the check valve seat 5. The contact between the inner conical surface of the check valve seat 5 and the O-ring 13 can make the sealing pressure evenly distributed on the contact surface. Compared with some other sealing methods, this uniform pressure distribution can better adapt to pressure changes in different directions and sizes. During the operation of the device, no matter how the liquid pressure fluctuates, it can maintain stable sealing performance and reduce the possibility of leakage; The booster anti-shake device 12 is connected between the liquid outlet five-way 8 and the one-way valve seat 5 through a transition joint 11. The booster anti-shake device 12 can effectively absorb and buffer the impact force of the water flow, reduce the vibration caused by the impact of the water flow, and reduce the impact of the vibration on the entire water injection system and the experimental process, so that the equipment can run more smoothly. At the same time, by reducing vibration, it can reduce the wear and damage to the equipment parts and components, and extend the service life of the equipment. At the same time, it can also reduce the problems of loose pipes and damage to connectors caused by vibration, improve the stability and safety of the entire system, and ensure the smooth progress of experiments or operations; There is a metal spherical seal between the one-way valve body B703 and the one-way valve core 702. The metal spherical seal can form a higher sealing pressure ratio on a smaller contact area by utilizing the close fit between the spherical surface and the corresponding surface, thereby effectively preventing the leakage of liquid or gas. Even under complex working conditions such as high pressure and high flow, it can maintain a good sealing effect to ensure that the medium flows along the prescribed path.

[0037] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A water injection and pressure maintaining device, characterized in that: It comprises a liquid inlet (1) connected to a liquid injection pump device, a liquid outlet (2) connected to a water injection chamber, a pressure measuring port (3) connected to a pressure gauge, and an overflow port (4), wherein the following are arranged in sequence between the liquid inlet (1) and the liquid outlet (2): A one-way valve seat (5) connected to the liquid inlet (1) via an adapter A (6); A liquid inlet check valve (7) is used to control the unidirectional flow of liquid, allowing high-pressure water to enter the subsequent components of the device during the water injection process and preventing liquid from flowing back during the pressure maintenance stage, thereby achieving a pressure maintenance function; Liquid outlet five-way (8), used for distributing and guiding the liquid; The pressure regulating valve (9) is configured such that the water flow is guided to the pressure regulating valve (9) by the liquid outlet five-way (8). The pressure measuring port (3) and the overflow port (4) are arranged on the pressure regulating valve (9). When the pressure in the device exceeds the upper safety limit, the pressure regulating valve (9) opens to allow the water to overflow through the overflow port (4), thereby regulating and stabilizing the pressure in the device. The liquid outlet end of the pressure regulating valve (9) is connected to the liquid outlet (2) via an adapter B (10).

2. A water injection and pressure maintaining device according to claim 1, characterized in that: The liquid outlet five-way (8) and the one-way valve seat (5) are connected to the boost anti-shake device (12) via a transition joint (11).

3. A water injection and pressure maintaining device according to claim 1, characterized in that: The liquid inlet check valve (7) comprises a check valve body A (701), a check valve core (702) and a check valve body B (703) which are connected in sequence, and a tower-shaped spring (704) is installed between the check valve core (702) and the check valve body B (703).

4. A water injection and pressure maintaining device according to claim 3, characterized in that: A metal spherical seal is formed between the one-way valve body B (703) and the one-way valve core (702).

5. The water injection and pressure maintaining device according to claim 1, characterized in that: The liquid inlet one-way valve (7) is sealed via an O-type sealing ring (13) and an inner conical surface of the one-way valve seat (5).

6. A water injection and pressure maintaining device according to claim 1, characterized in that: The liquid inlet (1) is connected to the water injection pump equipment via a rubber hose, and the connection method adopts a mining KJ type quick plug connector, which is quickly inserted and then installed with a U-shaped pin.

7. A water injection and pressure maintaining device according to claim 1, characterized in that: The pressure regulating valve (9) comprises a pressure regulating stud (901), a regulating spring (902), a regulating valve core A (903), a steel ball A (904), a regulating valve body (905), a regulating valve core B (906) and a steel ball B (907). The pressure regulating valve (9) is realized by rotating the pressure regulating stud (901) thereon.

8. A water injection and pressure maintaining device according to claim 7, characterized in that: The pressure regulating stud (901) and the regulating valve body (905) are assembled in a right-handed threaded manner. The regulating spring (902) is arranged on the pressure regulating stud (901). By rotating the pressure regulating stud (901), the preload force of the regulating spring (902) is changed, thereby changing the force acting on the regulating valve core A (903), the steel ball A (904), the regulating valve core B (906), and the steel ball B (907).

9. A method for using the water injection and pressure maintaining device according to any one of claims 1 to 8, characterized in that: The steps include: Step 1: Use a hose to connect the liquid inlet (1) of the water injection pressure maintaining device to the water injection pump equipment through a mining KJ-type quick-connect connector, and insert a U-shaped pin to ensure that the connection is firm and well sealed. Connect the liquid outlet (2) to the water injection chamber, connect the pressure measuring port (3) to the pressure gauge, and connect the overflow port (4) to a suitable liquid collection device; Step 2: Connect and install the adapter A (6), the one-way valve seat (5), the liquid inlet one-way valve (7), the transition joint (11), the liquid outlet five-way valve (8), the pressure regulating valve (9), the adapter B (10) and other components in sequence according to the design requirements, and ensure that the connections between the components are tight and accurate; Step 3: Turn on the water injection pump device, and high-pressure water flows in from the liquid inlet, passes through the adapter A (6) and enters the one-way valve seat (5). When the high-pressure water pressure reaches a certain value, it overcomes the elastic force of the tower spring (704) and pushes open the one-way valve core (702) of the liquid inlet one-way valve (7). The high-pressure water enters the boost and anti-shake device (12) through the small hole on the one-way valve body B (703) to perform boost and anti-shake processing. Then, the high-pressure water flows into the liquid outlet five-way (8) through the transition joint (11); Step 4: During the water injection process, the pressure in the device is monitored in real time by observing the pressure gauge connected to the pressure measuring port (3). According to the experimental requirements, the pressure regulating stud (901) of the pressure regulating valve (9) is rotated to adjust the overflow pressure upper limit. When the pressure in the device is normal, high-pressure water flows into the water injection chamber from the liquid outlet through the liquid outlet five-way (8) and the adapter B (10). When the pressure exceeds the safety upper limit, the pressure regulating valve (9) is opened, and the liquid is discharged through the overflow port (4) to reduce the pressure in the device. During the water injection chamber pressure test experiment and the pressure resistance value test, if the water injection chamber pressure is higher than the pressure of the liquid inlet (1), the high-pressure water at the rear end of the liquid inlet check valve (7) flows back, pushing the check valve core (702) to close, thereby realizing the pressure maintaining function. Step 5: After the experiment, turn off the water injection pump first, then disassemble the connecting parts according to the correct operating sequence, and clean and maintain the water injection and pressure maintaining device.

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