A high-voltage resistant electromagnetic flow sensor

Abstract

The invention discloses a high-voltage electromagnetic flow sensor, comprising a base tube (1); the base tube (1) has a cylindrical structure (2) at the bottom, the outer circle of the cylinder (2) is provided with an external thread (3), and the external thread (3) is threadedly connected to a lower joint (4); the base tube (1) at the top of the cylinder (2) is a round tube (8) structure, and an insulating sleeve (6) is provided between the base tube (1) and the shaft shoulder (5) of the outer circle of the lower joint (4); a group of electrodes (7) uniformly distributed along the circumference are provided on the insulating sleeve (6); the electrode (7) is in the shape of a screw, and the threaded section of the electrode (7) penetrates the round tube (8) of the base tube (1) and extends to the inner hole of the round tube (8) of the base tube (1). The invention replaces the solution of the existing electromagnetic flow sensor that uses internal filling of hydraulic oil to balance the external pressure, greatly simplifies the structure of the electromagnetic flow sensor, and improves the working reliability of the instrument.

Description

Technical Field

[0001] The invention relates to a high-pressure resistant electromagnetic flow sensor, belonging to the technical field of downhole instruments. Background Art

[0002] Electromagnetic flow testing technology is a flow testing technology developed based on Faraday's electromagnetic induction principle and is one of the conventional flow testing technologies in oil fields. Due to the limitations of the application environment, the electromagnetic flowmeters currently used for flow testing in oil wells are all external flow channel type with a diameter of (32-42) mm. The core of this type of instrument is the flow sensor part, which has basically the same structure and principle. This part consists of four metal electrodes evenly distributed on an outer tube with the same diameter as the instrument. An excitation coil is installed inside the outer tube. The magnetic field generated by the excitation coil penetrates the outer tube. The change in the flow rate of the external medium of the outer tube will generate an induced voltage on the electrode. The size of the external flow rate can be converted by the size of the induced voltage. According to the analysis of the test principle and application environment conditions, how to ensure that the metal electrode can withstand ultra-high external pressure while being insulated from the instrument casing has become a difficult point in the structural design of the electromagnetic flow sensor.

[0003] In order to meet the above requirements, the flow sensor part of the electromagnetic flow test products for oil fields is filled with hydraulic oil media, and the structure is designed with a balance piston or rubber capsule. When this part is subjected to external pressure, the hydraulic oil filled inside is compressed by the movement of the balance piston or the deformation of the rubber capsule. Due to the incompressibility of the liquid, this design can achieve pressure balance inside and outside the instrument, thereby making it possible to achieve electrode insulation in the structure while ensuring ultra-high compressive strength. However, the electromagnetic flow sensor with a dynamic pressure balance structure is very complex in structure, and is very difficult to produce and assemble. At the same time, this part also needs to be regularly filled with oil for maintenance on site, and the reliability of long-term work is very low. Therefore, the existing technology still has shortcomings and needs further improvement. Summary of the invention

[0004] The purpose of the present invention is to provide a high-voltage resistant electromagnetic flow sensor to solve the problems of the existing electromagnetic flow sensor, such as complex structure, difficult production and assembly, need for regular oil filling and maintenance, and low working reliability, so as to overcome the shortcomings of the prior art.

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

[0006] A high-voltage resistant electromagnetic flow sensor of the present invention comprises a base tube; the bottom of the base tube is a cylindrical structure, the outer circle of the cylinder is provided with an external thread, and the external thread is threadedly connected to a lower joint; the base tube at the top of the cylinder is a round tube structure, and an insulating sleeve is provided between the base tube and the axial shoulder of the outer circle of the lower joint; a group of electrodes evenly distributed along the circumference are provided on the insulating sleeve; the electrode is screw-shaped, and the threaded section of the electrode penetrates the round tube of the base tube and extends to the inner hole of the round tube of the base tube.

[0007] In the above-mentioned high-voltage resistant electromagnetic flow sensor, the insulating sleeve is made of high-strength engineering plastic polyetheretherketone.

[0008] In the above-mentioned high-voltage resistant electromagnetic flow sensor, the insulating sleeve is tightly sleeved on the base tube and the lower joint, and a zero-clearance interference fit is adopted between the insulating sleeve, the base tube and the lower joint.

[0009] In the above-mentioned high-voltage electromagnetic flow sensor, a sealing ring is used to seal the upper end of the insulating sleeve and the base tube and the lower end of the insulating sleeve and the lower joint, and the sealing rings at both ends of the insulating sleeve have the same model and specification.

[0010] In the above-mentioned high-voltage electromagnetic flow sensor, the axial section of the electrode is a T-shaped structure, an electrode cap is provided at one end of the electrode, a sealing groove is provided in the cylindrical section of the electrode, an electrode sealing ring is provided in the sealing groove; the electrode sealing ring is sealed and connected to the insulating sleeve.

[0011] In the above-mentioned high-voltage resistant electromagnetic flow sensor, the diameter of the electrode cap is 2 to 3 times the diameter of the electrode cylindrical section.

[0012] Due to the adoption of the above technical solution, the present invention realizes the requirement that the outer tube part of the electromagnetic flow sensor can withstand ultra-high external pressure while achieving electrode insulation, cancels the solution of the existing electromagnetic flow sensor using internal filling of hydraulic oil to balance the external pressure, greatly simplifies the structure of the electromagnetic flow sensor, and improves the working reliability of the instrument. The electromagnetic flow sensor structure of the present invention is suitable for the structural design of the flow sensor part of the underground external flow channel electromagnetic flowmeter for oil fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the present invention;

[0014] Figure 2 yes Figure 1 A partial enlarged view of the middle A part;

[0015] Figure 3 yes Figure 1 Axonometric drawing of .

[0016] The markings in the accompanying drawings are: 1-base tube, 2-cylinder, 3-external thread, 4-lower joint, 5-shoulder, 6-insulating sleeve, 7-electrode, 8-round tube, 9-sealing ring, 10-electrode cap, 11-sealing groove, 12-electrode sealing ring. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0018] A high-voltage electromagnetic flow sensor according to the present invention, Figures 1 to 3As shown, it includes a base tube 1; the bottom of the base tube 1 is a cylindrical body 2 structure, the outer circle of the cylindrical body 2 is provided with an external thread 3, and the external thread 3 is threadedly connected with the lower joint 4; the base tube 1 at the top of the cylindrical body 2 is a round tube 8 structure, and an insulating sleeve 6 is provided between the base tube 1 and the outer shoulder 5 of the lower joint 4; a group of electrodes 7 uniformly distributed along the circumference are provided on the insulating sleeve 6; the electrode 7 is in the shape of a screw, and the threaded section of the electrode 7 penetrates the round tube 8 of the base tube 1 and extends to the inner hole of the round tube 8 of the base tube 1. The insulating sleeve 6 is made of high-strength engineering plastic polyetheretherketone. The insulating sleeve 6 is tightly sleeved on the base tube 1 and the lower joint 4, and a zero-clearance interference fit is adopted between the insulating sleeve 6 and the base tube 1 and the lower joint 4. The upper end of the insulating sleeve 5 and the base tube 1 and the lower end of the insulating sleeve 5 and the lower joint 4 are sealed and connected by a sealing ring 9, and the sealing rings at both ends of the insulating sleeve 5 have the same model and specification. The axial section of the electrode 7 is a T-shaped structure, an electrode cap 10 is provided at one end of the electrode 7, a sealing groove 11 is provided in the cylindrical section of the electrode 7, an electrode sealing ring 12 is provided in the sealing groove 11, and the electrode sealing ring 12 is sealed and connected to the insulating sleeve 6. The diameter of the electrode cap 10 is 2 to 3 times the diameter of the cylindrical section of the electrode 7. Example

[0019] This example Figures 1 to 3 As shown, the main body of this example is composed of a base tube 1, an insulating sleeve 6 and a lower connector 4. The internal cavity of the base tube 1 is used to install other electronic components required by the sensor, such as coils. The insulating sleeve 6 is made of high-strength engineering plastic polyetheretherketone (PEEK) to ensure certain strength and insulation requirements. The insulating sleeve 6 is tightly sleeved on the base tube 1 and the lower connector 4, and the matching dimensions between them are interference fit to ensure that the internal gap of the insulating sleeve 6 is zero, so that when subjected to external pressure, the force borne by the insulating sleeve 6 will be evenly transmitted to the internal base tube 1 and the lower connector 4, and will not be damaged due to excessive deformation due to the internal cavity. The two ends of the insulating sleeve 6 are sealed by a sealing ring 9, and the two ends of the insulating sleeve 6 use sealing rings of exactly the same model and specification to ensure that the axial force on both sides of the insulating sleeve 6 is balanced under pressure. The insulating sleeve 6 has four electrodes 7 evenly distributed around the circumference, and the electrodes 7 are metal electrodes. The four electrodes 7 are sealed and installed on the insulating sleeve 6 through the electrode sealing ring 12 to ensure the insulation requirements between the electrodes 7 and other metal parts of the sensor. An electrode cap 10 is provided at one end of the electrode 7, and a force step is formed by the electrode cap 10. When the electrode 7 is subjected to external pressure, the force generated is borne by the electrode cap 10. The diameter of the electrode sealing ring 12 should be as small as possible, and the surface area of ​​the force step should be as large as possible, so that the force of the electrode 7 acting on the insulating sleeve 6 under the action of external pressure is as small as possible, ensuring that the insulating sleeve 6 will not be crushed. Since the insulating sleeve 6 is tightly sleeved on the base tube 1, the force of the electrode 7 acting on the insulating sleeve 6 will eventually be borne by the base tube 1. The force of the external pressure acting on the insulating sleeve 6 will be transferred to the base tube 1 and the lower joint 4 made of metal material, which significantly improves the pressure-bearing capacity of the electromagnetic flow sensor while ensuring the insulation of the electrode 7.

[0020] The present invention realizes the requirement that the outer tube of the electromagnetic flow sensor can withstand ultra-high external pressure while achieving electrode insulation, cancels the solution of the existing electromagnetic flow sensor using internal filling of hydraulic oil to balance the external pressure, greatly simplifies the structure of the electromagnetic flow sensor, and improves the working reliability of the instrument. The electromagnetic flow sensor structure of the present invention is suitable for the structural design of the flow sensor part of the underground external flow channel electromagnetic flowmeter for oil fields.

Claims

1. A high-voltage electromagnetic flow sensor, comprising a base tube (1); characterized in that: The bottom of the base tube (1) is a cylindrical structure (2), the outer circle of the cylindrical structure (2) is provided with an external thread (3), and the external thread (3) is threadedly connected to the lower joint (4); the base tube (1) at the top of the cylindrical structure (2) is a round tube (8) structure, and an insulating sleeve (6) is provided between the base tube (1) and the shaft shoulder (5) of the outer circle of the lower joint (4); a group of electrodes (7) evenly distributed along the circumference are provided on the insulating sleeve (6); the electrode (7) is screw-shaped, and the threaded section of the electrode (7) penetrates the round tube (8) of the base tube (1) and extends to the inner hole of the round tube (8) of the base tube (1).

2. The high-voltage electromagnetic flow sensor according to claim 1, characterized in that: The insulating sleeve (6) is made of high-strength engineering plastic polyetheretherketone.

3. The high-voltage electromagnetic flow sensor according to claim 1, characterized in that: The insulating sleeve (6) is tightly sleeved on the base tube (1) and the lower joint (4), and a zero-clearance interference fit is adopted between the insulating sleeve (6), the base tube (1) and the lower joint (4).

4. The high-voltage electromagnetic flow sensor according to claim 1, characterized in that: The upper end of the insulating sleeve (6) and the base tube (1) and the lower end of the insulating sleeve (6) and the lower joint (4) are sealed and connected by a sealing ring (9), and the sealing rings at both ends of the insulating sleeve (6) have the same model and specification.

5. The high-voltage electromagnetic flow sensor according to claim 1, characterized in that: The axial cross-section of the electrode (7) is a T-shaped structure; an electrode cap (10) is provided at one end of the electrode (7); a sealing groove (11) is provided in the cylindrical section of the electrode (7); an electrode sealing ring (12) is provided in the sealing groove (11); and the electrode sealing ring (12) is sealedly connected to the insulating sleeve (6).

6. The high-voltage electromagnetic flow sensor according to claim 5, characterized in that: The diameter of the electrode cap (10) is 2 to 3 times the diameter of the cylindrical section of the electrode (7).

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