A wellhead seal

Abstract

The utility model discloses a kind of oil extraction wellhead sealing devices, including the wellhead sealing device body of sleeve setting on polished rod, the wellhead sealing device body includes buffer cavity, the top and bottom of the buffer cavity are respectively fixedly connected with upper pipe and lower pipe, buffer cavity is installed with buffer pressure relief mechanism, upper pipe is threadedly sleeved with pressure cap, further include: automatic pressure relief mechanism, install on buffer cavity, the pressure situation of buffer cavity inner wall is monitored by automatic pressure relief mechanism, and automatic pressure relief is carried out.The utility model is through the setting of a series of structures, can be automatically timely pressure relief inside buffer cavity, can be real-time monitoring to the sealing lamination condition between elastic sealing ring and polished rod, and when cannot effectively laminate, automatically from the mode of lateral and vertical extrusion to elastic sealing ring is extruded adjustment, to effectively improve sealing effect, reduce the risk of leakage.

Description

Technical Field

[0001] This utility model relates to the field of oil wellhead sealing technology, and in particular to an oil wellhead sealing device. Background Technology

[0002] With the increasing demand for energy, oil extraction has become a crucial source of energy supply. As oilfield development and production extend, the workload of various processes at oil wells is increasing. Wellhead equipment is vital for ensuring normal oil well production. While there are many types and structures of production wellhead equipment, their shortcomings become increasingly apparent with repeated use. Components frequently fail, maintenance is difficult, and the lack of effective sealing structures easily leads to leaks. They cannot reliably perform multiple processes, have short service lives, and increase extraction costs. Furthermore, in the event of a blowout, existing wellhead sealing devices cannot release pressure promptly, resulting in oil waste, environmental pollution, and compromised personnel safety. Therefore, [the following is an excerpt from a document:] Announcement No.: CN215292 419U discloses an oil wellhead sealing device, including a buffer chamber. An upper pipe and a lower pipe, respectively connected to the upper and lower ends of the buffer chamber, are fixed thereto. An inner ring is fixed inside the buffer chamber, and an inner sleeve is fixed inside the inner ring. A polished rod passes through the inner sleeve and is slidably sealed to it. An inner concentric conical sleeve is fixed to the lower end of the inner sleeve, and the polished rod passes through the inner conical sleeve. A gap is provided between the inner conical sleeve and the bottom plate of the buffer chamber. An outer conical sleeve is fitted outside the inner conical sleeve, and the lower end of the outer conical sleeve is fixedly connected to the bottom plate of the buffer chamber. A gap is provided between the upper end of the outer conical sleeve and the inner ring. A gap is provided between the inner edge of the outer conical sleeve and the outer edge of the inner conical sleeve. A pipe connected to the buffer chamber is fixed on the buffer chamber. In the event of a blowout, the device can promptly release pressure, thereby avoiding oil waste and environmental pollution, ensuring the safety of workers, reducing costs, minimizing downhole accidents, and improving oilfield production efficiency.

[0003] The oil wellhead sealing device disclosed in the aforementioned patent can promptly relieve pressure in the event of a blowout through its buffer chamber and matching structure. However, it still has the following shortcomings during use: 1. The automation level of pressure relief inside the buffer chamber is low, requiring manual operation, which may result in untimely pressure relief; 2. It lacks a structure for real-time monitoring and adjustment of the sealing condition. The sealing ring is prone to aging after prolonged use, which may prevent it from effectively sealing against the polished rod. When the sealing effect is unsatisfactory, it cannot be automatically adjusted in time, thus posing a risk of leakage. In view of the above, this application proposes an oil wellhead sealing device. Utility Model Content

[0004] The purpose of this utility model is to address the shortcomings of existing technologies by proposing an oil wellhead sealing device.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An oil wellhead sealing device includes a wellhead sealing device body sleeved on a polished rod. The wellhead sealing device body includes a buffer chamber, with an upper pipe and a lower pipe fixedly connected to the top and bottom of the buffer chamber, respectively. A buffer pressure relief mechanism is installed inside the buffer chamber, and a pressure cap is threaded onto the upper pipe. The device also includes:

[0007] An automatic pressure relief mechanism is installed on the buffer chamber. This mechanism monitors the pressure on the inner wall of the buffer chamber and automatically relieves pressure.

[0008] An automatic sealing adjustment mechanism is installed on the upper pipe. This mechanism is used to monitor and automatically adjust the sealing effect.

[0009] The pressing mechanism, installed on the pressure cap and cooperating with the automatic sealing adjustment mechanism, is used to press the seal downwards;

[0010] The PLC controller is fixed on the top left side of the buffer chamber. The PLC controller is electrically connected to the automatic pressure relief mechanism, the automatic sealing adjustment mechanism, and the pressure fixing mechanism.

[0011] Preferably, the automatic pressure relief mechanism includes a first solenoid valve fixed to the bottom left side of the buffer chamber, a first pressure sensor fixedly connected to the top left side of the buffer chamber, the monitoring end of the first pressure sensor extending into the buffer chamber, and both the first solenoid valve and the first pressure sensor being electrically connected to a PLC controller. The PLC controller receives the signal from the first pressure sensor to control the first solenoid valve. The control principle is existing technology and will not be described in detail here.

[0012] Preferably, the automatic sealing adjustment mechanism includes multiple elastic sealing rings. Each elastic sealing ring is located inside the upper tube and movably fitted onto the guide rod. A first patch-type pressure sensor is embedded and fixed on the inner left side of the elastic sealing ring. The first patch-type pressure sensor is in close contact with the outer side of the guide rod and is used to monitor the adhesion force between the elastic sealing ring and the guide rod. A second patch-type pressure sensor is embedded and fixed on the top left side of the upper elastic sealing ring. Multiple annular elastic airbags are movably fitted inside the upper tube, with the elastic sealing rings movably fitted into the corresponding annular elastic airbags. A second solenoid valve is connected and fixed to the right side of each annular elastic airbag. The right side of the upper tube is sealed and movable. The system includes a flow divider box. The right sides of multiple second solenoid valves are connected and fixed to the left side of the flow divider box. A miniature air pump is fixedly installed on the top of the buffer chamber. The left side of the miniature air pump is the discharge end and is connected and fixed to an exhaust hood. The left side of the exhaust hood is connected and fixed to an explosion-proof hose. The left end of the explosion-proof hose is connected and fixed to the right side of the flow divider box. The miniature air pump provides airflow and transmits it into the flow divider box. The second solenoid valves, the first patch pressure sensor, the second patch pressure sensor, and the miniature air pump are all electrically connected to the PLC controller. The PLC controller receives the signal from the first patch pressure sensor to control the miniature air pump and the second solenoid valve. The control principle is existing technology and will not be elaborated here.

[0013] Preferably, the pressing mechanism includes an installation tube embedded and fixed to the top of the pressure cap, a pressure ring movably sleeved inside the upper tube, the pressure ring being sleeved on the smooth rod, the bottom of the pressure ring being in movable contact with the top of the upper elastic sealing ring, the pressure ring being used to compress the elastic sealing ring, the bottom of the pressure ring also being in movable contact with the top of the second patch pressure sensor, an electric telescopic rod being embedded and fixed to the bottom left of the installation tube, the bottom end of the output shaft of the electric telescopic rod being fixedly connected to the top left of the pressure ring, the electric telescopic rod being used to vertically drive the pressure ring, a guide rod being fixedly connected to the top right of the pressure ring, the installation tube being slidably sleeved on the guide rod, the guide rod providing a vertical guiding effect for the pressure ring, the electric telescopic rod being electrically connected to the PLC controller, the PLC controller receiving the signal from the second patch pressure sensor to control the electric telescopic rod, the control principle of which is existing technology and will not be elaborated further here.

[0014] Preferably, multiple through holes are provided on the inner wall of the right side of the upper tube. The second solenoid valve is located in the corresponding through hole and does not contact the inner wall of the through hole. A sealing gasket is bonded and fixed on the left side of the diversion box. The left side of the sealing gasket is in movable contact with the right side of the upper tube. The sealing gasket cooperates with multiple through holes to achieve a seal between the diversion box and the upper tube, thereby achieving the blocking and sealing of multiple through holes.

[0015] Preferably, the bottom of the buffer chamber is provided with a connecting hole that communicates with the inside of the lower pipe. The connecting hole is used to allow oil to enter the buffer chamber. The top of the outer side of the upper pipe is provided with an external thread, and the inner side of the pressure cap is provided with an internal thread. The external thread and the internal thread mesh with each other.

[0016] Preferably, the buffer pressure relief mechanism includes a first conical cover fixedly connected to the inner wall of the bottom of the buffer cavity, an inner sleeve fixedly installed inside the buffer cavity and slidably fitted on the light rod, and a second conical cover located inside the first conical cover fixedly fitted on the bottom outer side of the inner sleeve.

[0017] Compared with existing technologies, the beneficial effects of this utility model are:

[0018] 1. By setting up an automatic pressure relief mechanism and a PLC controller, the oil inside the buffer chamber can be automatically and promptly discharged to perform pressure relief when the pressure inside the buffer chamber is too high, thereby improving the timeliness and automation of pressure relief.

[0019] 2. By combining the automatic sealing adjustment mechanism with the PLC controller, the sealing fit between the elastic sealing ring and the smooth rod can be monitored in real time. When the fit cannot be effective, the elastic sealing ring and the smooth rod can be squeezed from the periphery to achieve effective fit, thereby improving the sealing effect. In addition, with the setting of the pressure fixing mechanism, the elastic sealing ring can be vertically squeezed and adjusted to further improve the tightness of the fit between the sealing ring and the smooth rod, and further improve the sealing effect.

[0020] This invention, through a series of structural designs, can automatically and promptly depressurize the interior of the buffer chamber, monitor the sealing fit between the elastic sealing ring and the smooth rod in real time, and automatically adjust the elastic sealing ring by squeezing from the periphery and vertically when it cannot fit effectively, thereby effectively improving the sealing effect and reducing the risk of leakage. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an oil wellhead sealing device proposed in this utility model;

[0022] Figure 2 This is a schematic diagram of the main cross-sectional structure of an oil wellhead sealing device proposed in this utility model;

[0023] Figure 3 for Figure 2 A magnified structural diagram of part A in the middle.

[0024] In the diagram: 100, smooth rod; 1, buffer chamber; 2, lower tube; 3, upper tube; 4, pressure cap; 5, automatic sealing adjustment mechanism; 501, elastic sealing ring; 502, annular elastic airbag; 503, first patch pressure sensor; 504, second patch pressure sensor; 505, shunt box; 506, second solenoid valve; 507, miniature air pump; 508, explosion-proof hose; 6, pressure fixing mechanism; 601, mounting tube; 602, electric telescopic rod; 603, guide rod; 604, pressure ring; 7, automatic pressure relief mechanism; 701, first solenoid valve; 702, first pressure sensor; 8, buffer pressure relief mechanism; 801, first conical cover; 802, second conical cover; 803, inner sleeve; 9, PLC controller. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0026] Reference Figure 1-2 An oil wellhead sealing device includes a wellhead sealing device body sleeved on a polished rod 100. The wellhead sealing device body includes a buffer chamber 1. An upper pipe 3 and a lower pipe 2 are fixedly connected to the top and bottom of the buffer chamber 1, respectively. A buffer pressure relief mechanism 8 is installed in the buffer chamber 1. A pressure cap 4 is threaded on the upper pipe 3. A connecting hole is opened at the bottom of the buffer chamber 1, which is connected to the inside of the lower pipe 2. The connecting hole is used to allow oil to enter the interior of the buffer chamber 1. An external thread is opened on the top of the outer side of the upper pipe 3, and an internal thread is opened on the inner side of the pressure cap 4. The external thread and the internal thread mesh with each other. The threaded connection makes it convenient for personnel to remove the pressure cap 4.

[0027] The buffer pressure relief mechanism 8 includes a first conical cover 801 fixedly connected to the inner wall of the bottom of the buffer cavity 1, an inner sleeve 803 fixedly installed in the buffer cavity 1 and slidably fitted on the light rod 100, and a second conical cover 802 located inside the first conical cover 801 fixedly fitted on the bottom outer side of the inner sleeve 803.

[0028] In this implementation plan: The existing device {publication (announcement) number}: CN215292419U discloses an oil wellhead sealing device. The buffer chamber 1, upper pipe 3, lower pipe 2, buffer pressure relief mechanism 8 and pressure cap 4 in this application document all adopt the same technical means as in this prior art. These technical means will not be described in detail here. Regarding the main body of this existing device, this application makes further improvements. For details, please refer to the disclosed technology below. In order to solve the technical problems existing in this prior art, such as the "1. The degree of automation of pressure relief inside the buffer chamber is low, requiring manual operation by personnel, and there is a situation of untimely pressure relief; 2. There is a lack of a structure for real-time monitoring and adjustment of the sealing condition. The sealing ring is prone to aging after long-term use, which makes it unable to effectively fit and seal with the polished rod. When the sealing effect is not ideal, it cannot be automatically adjusted in time, thus posing a risk of leakage." In combination with the use, this problem is obviously a real and difficult problem to solve. Therefore, in order to solve this technical problem, an automatic pressure relief mechanism 7, an automatic sealing adjustment mechanism 5, a pressure fixing mechanism 6 and a PLC controller 9 are added to this application document.

[0029] It should be noted that the accessories used in the buffer pressure relief mechanism 8 have been disclosed in publication number CN215292419U. Their performance can be referred to publication number CN215292419U. Furthermore, the inner conical sleeve, outer conical sleeve, inner sleeve, and sealing sleeve disclosed in the prior art are implemented in the same way as the first conical cover 801, inner sleeve 803, and second conical cover 802 disclosed in this application. They will not be described separately here.

[0030] Furthermore:

[0031] Reference Figure 1-3 An oil wellhead sealing device further includes:

[0032] Automatic pressure relief mechanism 7 is installed on buffer chamber 1;

[0033] PLC controller 9 is fixed on the top left side of buffer chamber 1;

[0034] The automatic pressure relief mechanism 7 includes a first solenoid valve 701 fixedly connected to the bottom left side of the buffer chamber 1, and a first pressure sensor 702 fixedly connected to the top left side of the buffer chamber 1. The monitoring end of the first pressure sensor 702 extends into the buffer chamber 1. Both the first solenoid valve 701 and the first pressure sensor 702 are electrically connected to the PLC controller 9. The PLC controller 9 receives the signal from the first pressure sensor 702 to control the first solenoid valve 701. The control principle is existing technology and will not be described in detail here.

[0035] In this implementation scheme: the first pressure sensor 702 detects the pressure inside the buffer chamber 1 in real time and converts the detected pressure signal into a standard electrical signal and transmits it to the PLC controller 9. When the pressure value reaches the set value, the PLC controller 9 controls the first solenoid valve 701 to open, so that the oil inside the buffer chamber 1 is discharged through the first solenoid valve 701. As the oil is discharged, the pressure inside the buffer chamber 1 gradually decreases. When the pressure value is lower than the preset value, the PLC controller 9 controls the first solenoid valve 701 to close, thereby achieving the purpose of automatically depressurizing the inside of the buffer chamber 1.

[0036] It should be noted that: the first pressure sensor 702 can preferably be a Siemens SITRANS P200, the PLC controller 9 can preferably be a Siemens S7-1200, and the first solenoid valve 701 can preferably be an EV210B. The specific principle is as follows: after the sensitive element inside the first pressure sensor 702 senses the pressure in the buffer chamber 1, it will undergo deformation or a change in electrical characteristics. This physical change is converted into a weak electrical signal. The signal conditioning circuit inside the first pressure sensor 702 amplifies this weak electrical signal and converts it into a standard industrial signal. This standard signal is transmitted long-distance via cable to the analog input module of the PLC controller 9. The analog input module of the PLC controller 9 converts the received standard electrical signal through an analog-to-digital converter (A / D). "The pressure is converted into a digital value for the CPU to process. The CPU compares this digital value with the pre-set upper and lower pressure limits in the program. If the detected pressure is greater than or equal to the upper limit setting, the digital output point of the PLC controller 9 is set. If the detected pressure is less than or equal to the lower limit setting, the output point is reset. The output point of the PLC controller 9 directly drives the first solenoid valve 701. When the PLC controller 9 outputs a signal, the coil of the first solenoid valve 701 is energized, generating a magnetic field that drives the valve core to open the valve channel and discharge oil. When the output of the PLC controller 9 is disconnected, the coil is de-energized, and the valve closes under the action of the spring. The specific control principle is existing technology and will not be described separately."

[0037] Furthermore:

[0038] An oil wellhead sealing device further includes an automatic sealing adjustment mechanism 5, which is installed on the upper pipe 3;

[0039] The automatic sealing adjustment mechanism 5 includes multiple elastic sealing rings 501. Each elastic sealing ring 501 is located inside the upper tube 3 and movably sleeved on the guide rod 100. A first patch-type pressure sensor 503 is embedded and fixed on the inner left side of each elastic sealing ring 501. The first patch-type pressure sensor 503 is in close contact with the outer side of the guide rod 100 and is used to monitor the adhesion force between the elastic sealing ring 501 and the guide rod 100. A fixed... A second patch-type pressure sensor 504 is fixedly installed. Multiple annular elastic airbags 502 are movably sleeved inside the upper tube 3. Elastic sealing rings 501 are movably sleeved within the corresponding annular elastic airbags 502. A second solenoid valve 506 is fixedly connected to the right side of each annular elastic airbag 502. A flow divider box 505 is movably sealed to the right side of the upper tube 3. The right sides of the multiple second solenoid valves 506 are all fixedly connected to the left side of the flow divider box 505. Multiple through holes are provided on the inner wall of the right side of the upper tube 3, and the second solenoid valves 506 are located at corresponding... The flow divider 505 has a sealing gasket bonded to its left side, which is in contact with the inner wall of the flow divider 505. The left side of the sealing gasket is in movable contact with the right side of the upper tube 3. The sealing gasket cooperates with multiple flow dividers, thereby achieving a seal between the flow divider 505 and the upper tube 3, thus achieving a seal for multiple flow dividers. A miniature air pump 507 is fixedly installed on the top of the buffer chamber 1. The left side of the miniature air pump 507 is the discharge end and is connected to and fixedly connected to an exhaust hood. The left side of the exhaust hood is connected to and fixedly connected to an explosion-proof hose 508. The left end of the hose 508 is connected and fixed to the right side of the distribution box 505. The miniature air pump 507 provides airflow and transmits it into the distribution box 505. The second solenoid valve 506, the first patch pressure sensor 503, the second patch pressure sensor 504, and the miniature air pump 507 are all electrically connected to the PLC controller 9. The PLC controller 9 receives the signal from the first patch pressure sensor 503 to control the miniature air pump 507 and the second solenoid valve 506. The control principle is existing technology and will not be described in detail here.

[0040] The explosion-proof hose 508 is designed to stretch and deform. When the annular elastic airbag 502 is squeezed, the second solenoid valve 506 will drive the diversion box 505 to move vertically, thereby stretching the explosion-proof hose 508 and providing a movable gap for the diversion box 505.

[0041] The clamping mechanism 6 is installed on the clamping cap 4;

[0042] The clamping mechanism 6 includes a mounting tube 601 embedded and fixed to the top of the clamping cap 4. A clamping ring 604 is movably sleeved inside the upper tube 3 and is fitted onto the smooth rod 100. The bottom of the clamping ring 604 is in movable contact with the top of the upper elastic sealing ring 501, and the clamping ring 604 is used to compress the elastic sealing ring 501. The bottom of the clamping ring 604 is also in movable contact with the top of the second patch pressure sensor 504, which is used to detect the compressive force of the clamping ring 604. An electric telescopic rod 602 is embedded and fixed to the bottom left side of the mounting tube 601. The top left side of the mounting tube 601 has an insertion hole for fixing the electric telescopic rod 602. The bottom end of the output shaft of the telescopic rod 602 is fixedly connected to the top left side of the pressure ring 604. The electric telescopic rod 602 is used to drive the pressure ring 604 vertically. A guide rod 603 is fixedly connected to the top right side of the pressure ring 604. The mounting tube 601 is slidably sleeved on the guide rod 603. The top right side of the mounting tube 601 has a guide hole that slides in contact with the outside of the guide rod 603. The guide rod 603 provides a vertical guide for the pressure ring 604. The electric telescopic rod 602 is electrically connected to the PLC controller 9. The PLC controller 9 receives the signal from the second patch pressure sensor 504 to control the electric telescopic rod 602. The control principle is existing technology and will not be described in detail here.

[0043] In this implementation scheme: During the sealing process, the first patch-type pressure sensor 503 continuously monitors the compressive force in contact with the polished rod 100 and converts the monitored pressure signal into a standard electrical signal, which is then transmitted to the PLC controller 9. When the pressure value is lower than the preset value, it indicates that a gap may occur between the elastic sealing ring 501 and the polished rod 100. The PLC controller 9 then controls the micro air pump 507 and the corresponding second solenoid valve 506 to open. The micro air pump 507 draws in external gas, which then passes sequentially through the conical shroud, the explosion-proof hose 508, the diversion box 505, and the corresponding second solenoid valve 506 into the annular elastic ring. Inside the annular elastic airbag 502, as the gas inside the annular elastic airbag 502 increases, the annular elastic airbag 502 gradually expands. Under the expansion force, it squeezes the corresponding elastic sealing ring 501 from the periphery, causing the elastic sealing ring 501 to deform and fit tightly against the smooth rod 100. At the same time, the first patch-type pressure sensor 503 detects the squeezing force. When the squeezing force reaches the preset value, the PLC controller 9 controls the corresponding second solenoid valve 506 and micro air pump 507 to close, thereby achieving the purpose of real-time monitoring and automatic adjustment of the sealing fit between the elastic sealing ring 501 and the smooth rod 100.

[0044] Meanwhile, the second patch-type pressure sensor 504 monitors the pressure of the pressure ring 604 and converts the monitored pressure signal into a standard electrical signal, which is then transmitted to the PLC controller 9. When the pressure value is lower than the preset value, the electric telescopic rod 602 is opened. The output shaft of the electric telescopic rod 602 drives the pressure ring 604 to move downward and squeeze the uppermost elastic sealing ring 501. The upper elastic sealing ring 501 squeezes the multiple elastic sealing rings 501 below in sequence, making the multiple elastic sealing rings 501 fit tightly together again. At the same time, the downward squeezing force causes the elastic sealing rings 501 to deform, further improving the tightness of the fit with the smooth rod 100 and further improving the sealing effect.

[0045] It should be noted that: the preferred model for the first surface-mount pressure sensor 503 is FlexiForce A201; the preferred model for the miniature air pump 507 is an FML series air pump; the preferred model for the second solenoid valve 506 is an S070 series solenoid valve; and the preferred model for the second surface-mount pressure sensor 504 is FlexiForce. A201, the electric telescopic pole 602 can preferably be an LA series electric telescopic pole. Its specific control principle is as follows: when the elastic sealing ring 501 is in contact with the smooth pole 100, there is an initial contact pressure. The first patch pressure sensor 503 generates a basic signal. When a gap occurs or the pressure is lower than the preset value, the reading of the first patch pressure sensor 503 drops. The first patch pressure sensor 503 converts the pressure signal into a standard electrical signal and transmits it to the PLC controller 9. The PLC controller 9 compares the received real-time pressure value with the pressure lower limit value set in the program. If the real-time value is less than the set value, the PLC controller 9 simultaneously starts the micro air pump 507 and opens the corresponding second solenoid valve 506. The gas drawn by the micro air pump 507 is filled into the annular elastic air bag 502.

[0046] The second patch-type pressure sensor 504 monitors the axial pressure of the pressure ring 604 on the uppermost elastic sealing ring 501 in real time and transmits its pressure electrical signal to the PLC controller 9. The PLC controller 9 compares the real-time value with a set lower limit value of axial pressure. If the real-time value is less than the set value, it indicates that all elastic sealing rings 501 as a whole may have worn or undergone compression creep, and the preload is insufficient. Then, the PLC controller 9 activates the electric telescopic rod 602. The above operations are all conventional applications of programmable controllers and will not be described in detail here.

[0047] In terms of power supply, all electrical components of this device are connected to the local mains power. They are connected to the power input interfaces of each device through conventional power distribution devices such as circuit breakers, contactors, and power modules (not marked in the figure) to form a complete and stable power supply circuit. This power supply scheme conforms to the conventional power distribution standards for industrial equipment and is a mature and well-known technical means, which will not be elaborated here.

[0048] Working principle: During use, the polished rod 100 is sealed by multiple elastic sealing rings 501. During the sealing process, the lower pipe 2 is fixed at the upper end of the wellhead. When a blowout occurs, the oil enters the second conical cover 802 through the lower pipe 2 and the connecting hole in sequence, and is discharged into the buffer chamber 1 through the gap between the second conical cover 802 and the first conical cover 801. This buffers and depressurizes the blowout oil, effectively preventing the occurrence of a blowout. The principle is disclosed in announcement number CN215292419U and is the same as it. It will not be elaborated here.

[0049] As the amount of oil inside the buffer chamber 1 increases, the internal pressure gradually increases. The pressure value for opening the first solenoid valve 701 is preset by the PLC controller 9. The first solenoid valve 701 is connected to the external oil collection pipe. The first pressure sensor 702 detects the pressure inside the buffer chamber 1 in real time and converts the detected pressure signal into a standard electrical signal, which is then transmitted to the PLC controller 9. When the pressure value reaches the preset value, the PLC controller 9 controls the first solenoid valve 701 to open, allowing the oil inside the buffer chamber 1 to be discharged through the first solenoid valve 701. As the oil is discharged, the pressure inside the buffer chamber 1 gradually decreases. When the pressure value is lower than the preset value, the PLC controller 9 controls the first solenoid valve 701 to close, thereby achieving the purpose of automatic pressure relief inside the buffer chamber 1 and improving the timeliness and automation of pressure relief.

[0050] The PLC controller 9 pre-sets the opening and closing pressure values ​​of the electric telescopic rod 602, as well as the opening and closing pressure values ​​of the micro air pump 507 and the second solenoid valve 506. After setting, the first patch-type pressure sensor 503 continuously monitors the compressive force in contact with the smooth rod 100 and converts the monitored pressure signal into a standard electrical signal, which is then transmitted to the PLC controller 9. When the pressure value is lower than the preset value, it indicates that a gap may have formed between the elastic sealing ring 501 and the smooth rod 100, posing a risk of leakage. Therefore, when the detected pressure value is lower than the preset value, the PLC controller 9 controls the micro air pump 507 and the corresponding second solenoid valve 506 to open. The micro air pump 507 draws in external gas, which passes sequentially through the conical hood, the explosion-proof hose 508, the diverter box 505, and the corresponding... The second solenoid valve 506 enters the annular elastic airbag 502. As the gas inside the annular elastic airbag 502 increases, the annular elastic airbag 502 gradually expands. Under the expansion force, it squeezes the corresponding elastic sealing ring 501 from the periphery. Under the squeezing force, the elastic sealing ring 501 deforms and fits tightly against the smooth rod 100. At the same time, the first patch pressure sensor 503 detects the squeezing force. When the squeezing force reaches the preset value, the PLC controller 9 controls the corresponding second solenoid valve 506 to close. After multiple second solenoid valves 506 are closed, the micro air pump 507 is controlled to close. This achieves real-time monitoring of the sealing fit between the elastic sealing ring 501 and the smooth rod 100, and timely automatic adjustment when the fit is not effective, thereby improving the sealing effect.

[0051] During the sealing process, the second patch-type pressure sensor 504 monitors the pressure of the pressure ring 604 and converts the monitored pressure signal into a standard electrical signal, which is then transmitted to the PLC controller 9. If the pressure value is lower than the preset value, it indicates that the elastic sealing ring 501 has aged and thinned, making it impossible for two adjacent elastic sealing rings 501 to make effective contact, and there is still a risk of leakage. When the pressure value is lower than the preset value, the electric telescopic rod 602 is controlled to open. The output shaft of the electric telescopic rod 602 drives the pressure ring 604 to move downward. The pressure ring 604 presses the uppermost elastic sealing ring 501 downward, and the upper elastic sealing ring 501 presses the multiple elastic sealing rings 501 below in sequence. Under the pressing force, the multiple elastic sealing rings 501 are tightly fitted again. At the same time, the downward pressing force causes the elastic sealing rings 501 to deform, further improving the tightness of the fit with the bare rod 100 and further improving the sealing effect.

[0052] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An oil wellhead sealing device, comprising a wellhead sealing device body sleeved on a polished rod (100), the wellhead sealing device body comprising a buffer chamber (1), an upper pipe (3) and a lower pipe (2) respectively fixedly connected to the top and bottom of the buffer chamber (1), a buffer pressure relief mechanism (8) installed in the buffer chamber (1), and a pressure cap (4) threaded onto the upper pipe (3), characterized in that, Also includes: An automatic pressure relief mechanism (7) is installed on the buffer chamber (1); The automatic sealing adjustment mechanism (5) is installed on the upper pipe (3); The pressure fixing mechanism (6) is installed on the pressure cap (4) and cooperates with the automatic sealing adjustment mechanism (5); The PLC controller (9) is fixed on the top left side of the buffer chamber (1). The PLC controller (9) is electrically connected to the automatic pressure relief mechanism (7), the automatic sealing adjustment mechanism (5), and the pressure fixing mechanism (6). The automatic pressure relief mechanism (7) includes a first solenoid valve (701) fixed to the bottom left side of the buffer chamber (1), a first pressure sensor (702) fixedly connected to the top left side of the buffer chamber (1), the monitoring end of the first pressure sensor (702) extending into the buffer chamber (1), and both the first solenoid valve (701) and the first pressure sensor (702) being electrically connected to the PLC controller (9). The automatic sealing adjustment mechanism (5) includes multiple elastic sealing rings (501). The elastic sealing rings (501) are located inside the upper tube (3) and are movably sleeved on the smooth rod (100). A first patch pressure sensor (503) is embedded and fixed on the left inner wall of the elastic sealing ring (501). The first patch pressure sensor (503) is in close contact with the outer side of the smooth rod (100). A second patch pressure sensor (504) is embedded and fixed on the top left side of the upper elastic sealing ring (501). Multiple annular elastic airbags (502) are movably sleeved inside the upper tube (3). The elastic sealing rings (501) are movably sleeved in the corresponding annular elastic airbags (502). The right side of the annular elastic airbags (502) is... A second solenoid valve (506) is fixedly connected to the upper pipe (3). A flow divider box (505) is sealed and movable on the right side of the upper pipe (3). The right sides of multiple second solenoid valves (506) are fixedly connected to the left side of the flow divider box (505). A micro air pump (507) is fixedly installed on the top of the buffer chamber (1). The left side of the micro air pump (507) is the discharge end and is fixedly connected to an exhaust hood. An explosion-proof hose (508) is fixedly connected to the left side of the exhaust hood. The left end of the explosion-proof hose (508) is fixedly connected to the right side of the flow divider box (505). The second solenoid valve (506), the first patch pressure sensor (503), the second patch pressure sensor (504) and the micro air pump (507) are all electrically connected to the PLC controller (9).

2. The wellhead sealing device according to claim 1, characterized in that, The clamping mechanism (6) includes an installation tube (601) embedded and fixed on the top of the pressure cap (4). A pressure ring (604) is movably sleeved inside the upper tube (3). The pressure ring (604) is sleeved on the smooth rod (100). The bottom of the pressure ring (604) is in movable contact with the top of the elastic sealing ring (501) above. The bottom of the pressure ring (604) is also in movable contact with the top of the second patch pressure sensor (504). An electric telescopic rod (602) is embedded and fixed on the bottom left side of the installation tube (601). The bottom end of the output shaft of the electric telescopic rod (602) is fixedly connected to the top left side of the pressure ring (604). A guide rod (603) is fixedly connected to the top right side of the pressure ring (604). The installation tube (601) is slidably sleeved on the guide rod (603). The electric telescopic rod (602) is electrically connected to the PLC controller (9).

3. The wellhead sealing device according to claim 1, characterized in that, Multiple through holes are provided on the inner wall of the right side of the upper tube (3). The second solenoid valve (506) is located in the corresponding through hole and does not contact the inner wall of the through hole. A sealing gasket is bonded and fixed on the left side of the diversion box (505). The left side of the sealing gasket is in contact with the right side of the upper tube (3). The sealing gasket cooperates with multiple through holes.

4. The wellhead sealing device according to claim 1, characterized in that, The bottom of the buffer cavity (1) is provided with a connecting hole that communicates with the inside of the lower tube (2), the top of the outer side of the upper tube (3) is provided with an external thread, and the inner side of the pressure cap (4) is provided with an internal thread, with the external thread meshing with the internal thread.

5. The wellhead sealing device according to claim 1, characterized in that, The buffer pressure relief mechanism (8) includes a first conical cover (801) fixedly connected to the inner wall of the bottom of the buffer cavity (1), an inner sleeve (803) fixedly installed in the buffer cavity (1) and sealed and slidably sleeved on the light rod (100), and a second conical cover (802) located inside the first conical cover (801) fixedly sleeved on the outer bottom of the inner sleeve (803).

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