A nuclear magnetic probe relay mounting bracket assembly and a nuclear magnetic probe

Abstract

The application discloses a nuclear magnetic probe relay mounting bracket assembly and a nuclear magnetic probe, and belongs to the technical field of oil exploration and development, which comprises an electrical connection assembly, a sealing assembly and a frequency adjusting assembly. The electrical connection assembly comprises an upper joint, a lower joint and a transition rod, and the upper joint and the lower joint are respectively connected to the two ends of the transition rod. The sealing assembly comprises a sealing plug body, a pressure-bearing sealing plug and a sealing plug pin. The sealing plug pin penetrates through the middle part of the sealing plug body and is sealingly connected to the middle part. The sealing plug pin is electrically connected to the lower joint. The pressure-bearing sealing plug is connected to the sealing plug body, and the sealing surface of the pressure-bearing sealing plug protrudes from the outer diameter side of the sealing plug body. The frequency adjusting assembly comprises a mounting disc for mounting a relay. The mounting disc is connected to one side of the sealing plug body close to the upper joint. The application can improve the sealing performance in the environment of an ultrahigh pressure wellbore and improve the frequency adjusting precision by sealing with the sealing assembly and adjusting frequency with the frequency adjusting assembly.

Description

Technical Field

[0001] This invention relates to the field of petroleum exploration and development technology, and in particular to a nuclear magnetic resonance (NMR) probe relay mounting bracket assembly and a NMR probe. Background Technology

[0002] In the field of oil exploration and development, accurate reservoir information is crucial for reservoir evaluation, resource estimation, and development planning. Traditional logging techniques are insufficient to meet the demands of complex exploration. Nuclear magnetic resonance (NMR) logging, with its ability to directly detect reservoir fluids, plays an irreplaceable and critical role in oil and gas exploration. By analyzing the NMR signals of fluids in formation pores, this technology can provide multidimensional reservoir parameters, accurately characterize reservoir features, and provide core evidence for reservoir evaluation, resource estimation, and development planning.

[0003] Nuclear magnetic resonance logging (NMR) measurements are unaffected by the rock skeleton, and the logging data is highly accurate and consistent, playing a crucial and irreplaceable role in oil and gas exploration, reservoir evaluation, and oil and gas extraction.

[0004] Nuclear magnetic resonance (NMR) logging instruments are high-precision instruments used in oil exploration. By detecting the relaxation characteristics of hydrogen nuclei in formation pore fluids, they obtain important formation information parameters such as reservoir permeability, porosity, oil saturation, and pore size distribution. Their core components include NMR electronic circuitry, NMR capacitor energy storage shorting circuitry, and an NMR probe. These three parts work together to achieve high-resolution magnetic resonance data acquisition in complex downhole environments.

[0005] Currently, in extreme environments such as oil exploration, especially deep oil and gas exploration and deep-sea exploration, there are problems with sealing failure and insufficient frequency modulation accuracy in ultra-high pressure wellbore environments. Summary of the Invention

[0006] The purpose of this invention is to provide a nuclear magnetic resonance probe relay mounting bracket assembly and a nuclear magnetic resonance probe to solve the problems existing in the prior art. By using a sealing component for sealing and a frequency adjustment component for frequency modulation, the sealing performance in ultra-high pressure wellbore environments can be improved and the frequency modulation accuracy can be increased.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] This invention provides an MRI probe relay mounting bracket assembly, including an electrical connection assembly, a sealing assembly, and a frequency adjustment assembly. The electrical connection assembly includes an upper connector, a lower connector, and a transition rod, with the upper connector and the lower connector respectively connected to both ends of the transition rod. The sealing assembly includes a sealing plug body, a pressure-bearing sealing plug, and a sealing plug pin. The sealing plug pin passes through and is sealed to the middle of the sealing plug body, and is electrically connected to the lower connector. The pressure-bearing sealing plug is connected to the sealing plug body, and the sealing surface of the pressure-bearing sealing plug protrudes from the outer diameter side of the sealing plug body. The frequency adjustment assembly includes a mounting plate for mounting the relay, and the mounting plate is connected to the side of the sealing plug body near the upper connector.

[0009] In one embodiment, the transition rod includes a sleeve and a guide rod, a first end of the sleeve is connected to the upper connector, a second end of the sleeve is sleeved and connected to the first end of the guide rod, and a second end of the guide rod is connected to the lower connector.

[0010] In one embodiment, the transition rod further includes a spring, a first step is provided on the inner diameter side of the rod sleeve, a second step is provided on the outer diameter side of the wire guide rod, the spring is sleeved on the wire guide rod, a first end of the spring abuts against the first step, and a second end of the spring abuts against the second step.

[0011] In one embodiment, the wire guide bar is provided with a wire passage for a straight wire to pass through, and the upper connector and the lower connector are electrically connected through the straight wire.

[0012] In one embodiment, the pressure-bearing sealing plug is provided with an annular groove, at least two annular grooves are spaced apart, the annular groove is used to install a sealing ring, and a retaining ring is provided on the outer diameter side of the sealing ring.

[0013] In one embodiment, the sealing ring is made of fluororubber, with a temperature resistance of -20℃ to 260℃; the retaining ring is made of PEEK, with a hardness of 90HRB to 95HRB, and suppresses the deformation of the sealing ring to ≤0.1mm under a pressure of 170MPa.

[0014] In one embodiment, the pressure-bearing sealing plug is manufactured using a glass-metal sintering process. During sintering at 500°C to 700°C, atomic-level diffusion occurs between the borosilicate glass and the metal alloy surface, forming a transition layer with a thickness of 5μm to 10μm and an interfacial bonding strength >200MPa.

[0015] In one embodiment, both the sealing plug body and the sealing plug pin are made of nickel-based alloy and are fused together. The surface of the sealing plug pin is coated with a nickel-gold plating system.

[0016] The present invention also provides an MRI probe, including an MRI probe relay mounting bracket assembly as described above, wherein a relay is mounted on the mounting plate, the input terminal of the relay is electrically connected to the MRI electronic circuit via a control line, and the high voltage terminal of the relay is connected to the MRI probe frequency modulation circuit.

[0017] In one embodiment, four relays are provided, and three sets of control lines are provided. The relay control signals output by the nuclear magnetic resonance electronic circuit control the opening / closing actions of the four relays respectively through the control lines. Specifically, the first set of control lines controls the first and second relays to operate simultaneously; the second set of control lines controls the third relay to operate; and the third set of control lines controls the fourth relay to operate.

[0018] The three sets of six high-voltage lines output from the high-voltage terminals of the first, third, and fourth relays are respectively connected to C3, C1, and C7 of the frequency modulation capacitor board. The two high-voltage terminals of the second relay are respectively connected to capacitor C6 on the fixed capacitor board and 1TURN of the transmitting antenna. The other end of capacitor C6 is connected to 2TURN of the transmitting antenna.

[0019] The four high-voltage lines output by the nuclear magnetic resonance electronic circuit are respectively connected to the two ends of C2, fixed capacitor C4, transmitting antenna, and fixed capacitor C5 of the nuclear magnetic resonance probe frequency modulation circuit.

[0020] The present invention achieves the following technical effects compared to the prior art:

[0021] This invention achieves electrical connection between the nuclear magnetic resonance electronic circuit and the nuclear magnetic resonance probe frequency modulation circuit through an electrical connection component. Conductivity and effective sealing are achieved inside the sealing plug body using a sealing plug pin, while a pressure-bearing sealing plug provides external sealing, ensuring the sealing performance of the sealing component. A relay is installed using a mounting plate, enabling frequency modulation via the relay. Therefore, this invention utilizes a sealing component for sealing and a frequency modulation component for frequency modulation, thereby improving sealing performance and frequency modulation accuracy in ultra-high pressure wellbore environments. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is an exploded structural diagram of the nuclear magnetic resonance probe relay mounting bracket assembly in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the axial section of the nuclear magnetic resonance probe relay mounting bracket assembly in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the electrical connection and control principle in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the control principle of a single relay in an embodiment of the present invention;

[0027] Among them, 1. upper connector; 2. pole sleeve; 3. wire guide pole; 4. relay; 5. mounting plate; 6. lower connector; 7. pressure-bearing sealing plug; 8. sealing plug body; 9. spring; 10. control line; 11. sealing plug pin; 12. straight line; 21. first step; 31. second step. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The purpose of this invention is to provide a nuclear magnetic resonance probe relay mounting bracket assembly and a nuclear magnetic resonance probe to solve the problems existing in the prior art. By using a sealing component for sealing and a frequency adjustment component for frequency modulation, the sealing performance in ultra-high pressure wellbore environments can be improved and the frequency modulation accuracy can be increased.

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] like Figures 1-4As shown, this invention provides an assembly of a nuclear magnetic resonance (NMR) probe relay mounting bracket, including an electrical connection assembly, a sealing assembly, and a frequency adjustment assembly. The electrical connection assembly includes an upper connector 1, a lower connector 6, and a transition rod. The upper connector 1 and lower connector 6 are respectively connected to the two ends of the transition rod, which supports and fixes them. The upper connector 1 is used to connect to the lower connector of the NMR electronic circuit, and the lower connector 6 is used to connect to the NMR probe frequency modulation circuit. The transition rod can be a single rod structure or a multi-rod combination structure. The sealing assembly includes a sealing plug body 8, a pressure-bearing sealing plug 7, and a sealing plug pin 11. The sealing plug pin 11 penetrates and seals the middle of the sealing plug body 8, and is electrically connected to the lower connector 6. The pressure-bearing sealing plug 7 is connected to the sealing plug body 8, and its sealing surface protrudes from the outer diameter side of the sealing plug body 8, achieving a seal between the pressure-bearing sealing plug 7 and the mounted structure. The frequency adjustment assembly includes a mounting plate 5 for mounting a relay 4. The mounting plate 5 is connected to the side of the sealing plug body 8 near the upper connector 1. The mounting plate 5 may be annularly fitted onto the outer diameter side of the transition rod, and there may be a gap between the mounting plate 5 and the transition rod for wiring.

[0032] This invention achieves electrical connection between the NMR electronic circuit connector and the NMR probe frequency modulation circuit through an electrical connection component. The sealing plug body 8 is connected and effectively sealed using a sealing plug pin 11 inside, and sealed externally using a pressure-bearing sealing plug 7. This ensures the sealing performance of the sealing component. A relay 4 is installed using a mounting plate 5, enabling frequency modulation via the relay 4. Thus, this invention utilizes a sealing component for sealing and a frequency modulation component for frequency modulation, thereby improving sealing performance and frequency modulation accuracy in ultra-high pressure wellbore environments.

[0033] In one embodiment, the mounting plate 5 (aluminum alloy 7075-T6, anodized conductive yellow treatment) is provided with a U-shaped mounting groove. The relay 4 is fixed in the U-shaped mounting groove using an M3 hexagonal screw. Combined with RTV silicone rubber (Shore hardness 50A) to fill the gap, it can resist impact and prevent problems such as increased contact resistance and damage to the relay 4 caused by vibration, thus ensuring the reliable operation of the instrument.

[0034] In one implementation, such as Figure 1 and Figure 2 As shown, the transition rod includes a sleeve 2 and a guide rod 3. The sleeve 2 is a hollow structure. The first end of the sleeve 2 is connected to the upper connector 1. The upper connector 1 can be inserted into the first end of the sleeve 2 to realize the installation and fixation of the upper connector 1 and the sleeve 2. The second end of the sleeve 2 is sleeved and connected to the first end of the guide rod 3 to realize the installation and fixation of the sleeve 2 and the guide rod 3. The second end of the guide rod 3 is connected to the lower connector 6.

[0035] In this example, the transition pole adopts a tubular sleeve structure (material: 7075-T6 aluminum alloy) consisting of pole sleeve 2 and wire guide pole 3. An internal channel for a 19-core straight-through wire 12 is provided, and externally, six control wires 10 and four high-voltage pulse wires (16G red / white twisted pair) are fixed with insulating tape. The insulating tape (temperature resistant to 175℃) is wrapped and reinforced. After a certain period of vibration testing, no damage or wear was observed, and the wire insulation layer remained 100% intact.

[0036] In this example, control line 10 is used to transmit 27-30VDC relay on / off drive signals. It controls four K40-P relays through a differential wiring (twisted pair) design, with a switching response time of <10ms, ensuring real-time transmission of frequency modulation commands.

[0037] In one implementation, such as Figure 1 and Figure 2 As shown, the transition rod also includes a spring 9. A first step 21 is provided on the inner diameter side of the sleeve 2, and a second step 31 is provided on the outer diameter side of the guide rod 3. After the sleeve 2 and the guide rod 3 are inserted, there is a gap between the first step 21 and the second step 31. The spring 9 is sleeved on the guide rod 3, with its first end abutting against the first step 21 and its second end abutting against the second step 31. Through the spring 9, the sleeve 2 and the guide rod 3 can slide relative to each other axially and have a certain degree of elasticity. When installing the upper connector 1, this provides a buffer, preventing damage caused by a rigid connection.

[0038] In one implementation, such as Figure 1 and Figure 2 As shown, the wire guide rod 3 is provided with a wire passage for the straight wire 12 to pass through, which facilitates the arrangement of the straight wire 12. The upper connector 1 and the lower connector 6 are electrically connected through the straight wire 12.

[0039] In this example, the upper connector 1 is a connector for an 18-core straight-through cable 12. This straight-through cable 12 is designed to provide power (such as 120Vac main power and auxiliary power) and a bidirectional communication interface (for command transmission and measurement data upload) to the downstream instruments when the NMR instrument is connected to other logging instruments. If no downstream instrument is needed, the straight-through cable 12 can be removed, leaving only the plug and socket insulation sleeve (PTFE material, temperature resistant to 200℃) to avoid the risk of short circuits.

[0040] In this example, the straight-through line 12 uses 19 high-temperature conductors (polyimide insulation layer, temperature resistance 260℃), and achieves electrical connection through the lower connector 6.

[0041] In one implementation, such as Figure 1 and Figure 2As shown, the pressure-bearing sealing plug 7 is provided with annular grooves, with at least two annular grooves spaced apart. The annular grooves are used to install the sealing ring, and a retaining ring is provided on the outer diameter side of the sealing ring. The sealing ring further improves the sealing performance, and the retaining ring can suppress the maximum deformation of the sealing ring and protect it. Through the setting of the sealing ring and the retaining ring, the pressure resistance of the pressure-bearing sealing plug 7 is improved, and it can withstand well mud pressure ≥170MPa (traditional products are only 140MPa), preventing mud from entering the instrument and protecting components such as the relay 4 and the frequency modulation capacitor board from ultra-high pressure mud corrosion and short circuit risks. It is suitable for ultra-deep well operations with depths of 7000 meters to 10000 meters.

[0042] In this example, the lower connector 6, installed inside the pressure-bearing sealing plug 7, is a 37-pin plug. The outer 18 pins are for the NMR instrument signal channel, and the inner 19 pins are for the 12-channel straight-through line. The insulation resistance is greater than 1000MΩ (compared to approximately 500MΩ for traditional products), and the withstand voltage is 2000V, ensuring high-frequency, high-voltage signal transmission.

[0043] In one embodiment, the sealing ring is made of fluororubber, with a temperature resistance of -20℃ to 260℃; the retaining ring is made of PEEK, with a hardness of 90HRB to 95HRB, and suppresses the deformation of the sealing ring to ≤0.1mm under a pressure of 170MPa, which can effectively prevent the sealing ring from being extruded and broken, and has a significant improvement over traditional sealing methods.

[0044] In one embodiment, the pressure-bearing sealing plug 7 employs a glass-to-metal sintering process. During sintering at 500℃ to 700℃, atomic-level diffusion occurs between the borosilicate glass and the metal alloy surface, forming a transition layer with a thickness of 5μm to 10μm. The interfacial bonding strength is >200MPa, far exceeding the design pressure of 175MPa. The glass phase becomes amorphous after cooling, with an internal micro-porosity of <0.1%, effectively blocking fluid permeation paths. Glass-to-metal sintering (GTMS) is a process that forms a hermetically tight seal by sintering glass and metal at high temperatures. This process is widely used in electronic packaging, aerospace, oil exploration (such as pressure sealing for nuclear magnetic resonance logging instruments), and medical devices to achieve highly reliable, high-pressure resistant, and corrosion-resistant sealing structures. Through cross-disciplinary innovation in materials science and mechanical design, GTMS sealing overcomes the bottlenecks of traditional sealing technologies in ultra-high pressure and wide-temperature range scenarios, providing a core sealing solution for extreme environments such as deep oil and gas exploration and deep-sea exploration. Compared with traditional designs, the present invention utilizes the insulating properties of the glass-metal sintered layer to avoid interference from leakage current of high-voltage, high-current transmission pulses, ensuring the capacitor switching of the LC frequency modulation circuit and the stable transmission of nuclear magnetic resonance signals, thus providing a strong guarantee for the quality of nuclear magnetic logging in extreme environments (high temperature, high pressure).

[0045] In one embodiment, both the sealing plug body 8 and the sealing plug pin 11 are made of nickel-based alloy and are fused together to ensure connection strength. The surface of the sealing plug pin 11 is coated with a nickel-gold plating system. Electroless Nickel / Immersion Gold (ENIG) plating is a high-performance surface treatment technology widely used in electronic packaging, PCB (printed circuit board), semiconductors, aerospace, and other fields. This system consists of a chemically plated nickel (Ni) layer and a chemically immersed gold (Au) layer, possessing excellent solderability, conductivity, corrosion resistance, and oxidation resistance.

[0046] In this example, both the sealing plug body 8 and the sealing plug pin 11 are made of Inconel X-750 nickel-based alloy (Ni≥70%, Cr 14-17%, Ti 2.25-2.75%), which undergoes double aging treatment, resulting in high tensile strength and strong corrosion resistance in H2S-containing slurry, with a corrosion rate ≤0.05mm / year. The surface of the sealing plug pin 11 adopts a "nickel (75±25μm) + gold (75±15μm)" plating system, with a contact resistance <1Ω and strong oxidation resistance at 200℃, ensuring reliable electrical connection in extreme environments (high temperature, high pressure).

[0047] The nuclear magnetic resonance detection relay mounting bracket assembly of the present invention has the following functions:

[0048] Electrical connection function: Connects to the NMR electronic circuitry at the top and the NMR probe frequency modulation circuit (frequency modulation capacitor board and fixed capacitor board, etc.) at the bottom; and enables the instrument's straight-through line 12 to pass through.

[0049] Frequency modulation: Under the control of the relay control signal transmitted from the nuclear magnetic resonance electronic circuit, the four relays 4 switch their on / off states, change the capacitance value of the capacitor connected to the probe antenna, and form a high-voltage transmission pulse with 5 frequency bands according to the mechanism of the LC frequency modulation circuit.

[0050] Pressure-bearing seal: The sealing component has a built-in 19-core channel to realize signal transmission between the mounting plate 5 and the frequency modulation circuit of the nuclear magnetic probe; it adopts a glass-metal sintered sealing structure to withstand well mud pressure of ≥175MPa, preventing mud from entering the instrument under high pressure environment, protecting electrical components such as relay 4 and circuit board from corrosion and short circuit risks, and ensuring safe operation of logging operations in ultra-deep wells (such as depths below 8000m).

[0051] Relay 4 is installed, and control line 10, high-voltage transmission pulse connection, etc. are soldered and wired.

[0052] like Figures 1-4As shown, the present invention also provides an NMR probe, including an NMR probe relay mounting bracket assembly as described above. A relay 4 is mounted on the mounting plate 5. The input terminal of the relay 4 is electrically connected to the NMR electronic circuit through the control line 10. The high voltage terminal of the relay 4 is connected to the NMR probe frequency modulation circuit. The NMR probe frequency modulation circuit includes a frequency modulation capacitor board and a fixed capacitor board, etc. By switching the on / off position, the capacitance value connected to the probe's transmitting / receiving antenna is changed. According to the LC circuit (inductor-capacitor circuit) principle, five transmitting pulses of different frequency bands are formed.

[0053] like Figure 4 The diagram shows the control principle of a single relay. E1 and E2 are connected to control line 10. Relay 4 has two on / off control lines, with control signals being 26VDC-30VDC DC voltage signals. The voltages (+ / -) of the two control lines 10 are different, meaning the current directions are different. After passing through the diode in the diagram, the current flowing through the relay's coil in different directions controls the closing / opening of the high-voltage output terminals A1 and A2 of relay 4. The voltage across control line 10 is 30V, specifically +15VDC and -15VDC, representing the current directions applied to control line 10.

[0054] When E1 is positive and E2 is negative, diodes D2 and D1 are on, diode D5 is off, the current flowing through the coil is from right to left, relay 4 is energized, and A1 and A2 are connected; when E1 is negative and E2 is positive, diodes D5 and D6 are on, D4 is off, the current flowing through the coil is from left to right, relay 4 is open, and A1 and A2 are disconnected.

[0055] Mechanism: The different "on / off" states of A1 and A2 result in different capacitance values ​​connected to the transmitting antenna.

[0056] In one embodiment, it also includes red / white high-voltage lines, which are provided in two sets. The two sets of 16G conductors (silver-plated copper core, current carrying capacity 20A) are connected to the lower connectors Pin26 / 27 and Pin28 / 29 of the nuclear magnetic resonance electronic circuit to transmit 500-1500V high-voltage transmission pulses. They are connected to the frequency modulation capacitor board at the bottom and meet the high-voltage and high-current requirements of nuclear magnetic resonance emission.

[0057] In one implementation, such as Figure 3 As shown, there are four relays 4 and three sets of control lines 10. The relay control signals output by the nuclear magnetic resonance electronic circuit control the opening and closing actions of the four relays 4 respectively through the control lines 10. The first set of control lines controls the first and second relays to operate simultaneously; the second set of control lines controls the third relay to operate; and the third set of control lines controls the fourth relay to operate.

[0058] The three sets of six high-voltage lines output from the high-voltage terminals of the first, third, and fourth relays are respectively connected to C3, C1, and C7 of the frequency modulation capacitor board. The two high-voltage terminals of the second relay are respectively connected to capacitor C6 on the fixed capacitor board and 1TURN of the transmitting antenna. The other end of capacitor C6 is connected to 2TURN of the transmitting antenna.

[0059] The four high-voltage lines output from the nuclear magnetic resonance electronic circuit are connected to C2, fixed capacitor C4, transmitting antenna, and fixed capacitor C5 on the frequency modulation capacitor board, respectively. Four K40-P type high-voltage relays 4 (temperature resistance 175℃, contact resistance <1Ω) switch the 81nF to 55nF capacitors through matrix switching logic (as shown in Table 1) to achieve frequency band adjustment from 590kHz to 770kHz with a frequency error ≤0.5%.

[0060] In this example, as Figure 3 As shown, the relay control signal output from the NMR electronic circuit lower connector controls the opening / closing actions of four relays 4, namely K11, K12, K13, and K14, through three sets of six control lines 10 on the mounting bracket 5, namely 24, 25, 20, 21, 22, and 23. Specifically, control lines 24 and 25 control K11 and K12 to operate simultaneously; lines 20 and 21 control K13; and lines 22 and 23 control K14.

[0061] Figure 3 The intermediate relay mounting bracket assembly outputs three sets of six high-voltage wires from the high-voltage terminals K11, K13, and K14, respectively, which are connected to C3, C1, and C7 of the frequency modulation capacitor board. The two high-voltage output terminals of K12 are connected to the 1TURN of the transmitting antenna (probe transmitting / receiving antenna) of capacitor C6 on the fixed capacitor board, and the other end of capacitor C6 is connected to the 2TURN of the transmitting antenna (probe transmitting / receiving antenna). The four high-voltage wires 26, 27, 28, and 20 from the NMR electronic circuit lower connector are connected to the two ends of capacitor C2, fixed capacitor C4, transmitting antenna, and fixed capacitor C5 on the frequency modulation capacitor board, respectively.

[0062] Relay control signals from the nuclear magnetic resonance (NMR) circuit control the on / off states of four relays according to different measurement modes. In the high-voltage pulse transmission circuit, the capacitance value connected to the transmitting antenna L is continuously changed, generating five frequency bands of transmission pulses based on the LC oscillation circuit principle. The transmission frequency bands are 590±5kHz, 616±5kHz, 640±5kHz, 680±5kHz, and 770±5kHz.

[0063] like Figure 3As shown, the relay control signals output by the nuclear magnetic resonance electronic circuit control four relays K11, K12, K13, and K14 respectively through three groups of six control lines 10. Lines 24 and 25 simultaneously control K11 and K12, so the on / off states of these two relays 4 are the same. Lines 20 and 21 control K13, and lines 22 and 23 control K14. When K11 and K12 are closed, capacitors C34.8nF and C610nF are connected to the transmitting antenna; when open, they are not connected. When K13 is closed, C13.6nF is connected to the antenna transmitting circuit; when open, it is not connected. When K14 is closed, C7 is connected to the antenna transmitting circuit; when open, it is not connected.

[0064] Table 1: Capacitor values ​​for each frequency band in relay control and transmitting circuit

[0065]

[0066] In Table 1, +15 and -15 indicate the current direction of the relay control signal. The capacitance values ​​represent the capacitance values ​​connected to the transmitting antenna for different frequency bands. As can be seen from Table 1, the coordinated switching operation of the four relays determines the five capacitance values ​​connected to the transmitting antenna for the five frequency bands, thereby adjusting the frequency range of the transmitted pulse.

[0067] Table 2: Capacitance values ​​for each frequency band

[0068]

[0069] In Table 2, the inductance value of the nuclear magnetic resonance transmitting antenna is L≈0.90uH. Calculate the frequency value for a certain frequency band using the calculation formula for LC circuits:

[0070] For example: BAND 0, inductance L≈0.90uH, capacitance C=81.2nF,

[0071] According to the formula The calculated frequency is f≈590kHz.

[0072] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A nuclear magnetic resonance probe relay mounting bracket assembly, characterized in that, include: An electrical connection assembly, comprising an upper connector, a lower connector, and a transition rod, wherein the upper connector and the lower connector are respectively connected to both ends of the transition rod; A sealing assembly, comprising a sealing plug body, a pressure-bearing sealing plug, and a sealing plug pin, wherein the sealing plug pin passes through and is sealed to the middle of the sealing plug body, the sealing plug pin is electrically connected to the lower connector, the pressure-bearing sealing plug is connected to the sealing plug body, and the sealing surface of the pressure-bearing sealing plug protrudes from the outer diameter side of the sealing plug body. And a frequency adjustment assembly, the frequency adjustment assembly including a mounting plate for mounting a relay, the mounting plate being connected to the side of the sealing plug body near the upper connector; The transition rod includes a rod sleeve and a wire guide rod. The first end of the rod sleeve is connected to the upper connector, the second end of the rod sleeve is sleeved and connected to the first end of the wire guide rod, and the second end of the wire guide rod is connected to the lower connector. The transition rod also includes a spring. The inner diameter side of the rod sleeve is provided with a first step, and the outer diameter side of the wire guide rod is provided with a second step. The spring is sleeved on the wire guide rod, with the first end of the spring abutting against the first step and the second end of the spring abutting against the second step. The cable guide rod is provided with a cable passage for a straight cable to pass through, and the upper connector and the lower connector are electrically connected through the straight cable; The pressure-bearing sealing plug is provided with an annular groove, and at least two annular grooves are provided at intervals. The annular groove is used to install the sealing ring, and a retaining ring is provided on the outer diameter side of the sealing ring.

2. The MRI probe relay mounting bracket assembly according to claim 1, characterized in that: The sealing ring is made of fluororubber and is resistant to temperatures from -20℃ to 260℃. The retaining ring is made of PEEK material with a hardness of 90HRB to 95HRB and can suppress the deformation of the sealing ring to ≤0.1mm under a pressure of 170MPa.

3. The MRI probe relay mounting bracket assembly according to claim 1, characterized in that: The pressure-bearing sealing plug is manufactured using a glass-metal sintering process. During sintering at 500℃~700℃, atomic-level diffusion occurs between the borosilicate glass and the metal alloy surface, forming a transition layer with a thickness of 5μm~10μm and an interfacial bonding strength >200MPa.

4. The MRI probe relay mounting bracket assembly according to claim 1, characterized in that: Both the sealing plug body and the sealing plug pin are made of nickel-based alloy and are fused together. The surface of the sealing plug pin is coated with a nickel-gold plating system.

5. An nuclear magnetic resonance (NMR) probe, characterized in that: The assembly includes the nuclear magnetic resonance probe relay mounting bracket as described in any one of claims 1-4, wherein a relay is mounted on the mounting plate, the input terminal of the relay is electrically connected to the nuclear magnetic resonance electronic circuit via a control line, and the high-voltage terminal of the relay is connected to the nuclear magnetic resonance probe frequency modulation circuit.

6. The nuclear magnetic resonance probe according to claim 5, characterized in that: The system includes four relays and three sets of control lines. The relay control signals output by the nuclear magnetic resonance electronic circuit control the opening and closing actions of the four relays respectively through the control lines. Specifically, the first set of control lines controls the first and second relays to operate simultaneously; the second set of control lines controls the third relay to operate; and the third set of control lines controls the fourth relay to operate. The three sets of six high-voltage lines output from the high-voltage terminals of the first, third, and fourth relays are respectively connected to C3, C1, and C7 of the frequency modulation capacitor board. The two high-voltage terminals of the second relay are respectively connected to capacitor C6 on the fixed capacitor board and 1TURN of the transmitting antenna. The other end of capacitor C6 is connected to 2TURN of the transmitting antenna. The four high-voltage lines output by the nuclear magnetic resonance electronic circuit are respectively connected to the two ends of C2, fixed capacitor C4, transmitting antenna, and fixed capacitor C5 of the frequency modulation capacitor board.

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