CN113137996B - Sectional capacitance sensor and multiphase layered liquid level interface measurement system - Google Patents

Abstract

The invention discloses a segmented capacitance sensor and a multi-phase layered liquid level interface measuring system, wherein the sensor comprises a plurality of sensor nodes, each sensor node comprises a segmented capacitance polar plate I, a segmented capacitance polar plate I signal adapter plate, a segmented capacitance detecting circuit, a segmented capacitance polar plate I shell, a segmented capacitance polar plate II signal adapter plate, a segmented capacitance polar plate II shell, a power supply and a communication line, the segmented capacitance polar plate I and the segmented capacitance polar plate II are placed in parallel, a plurality of capacitance electrodes I are arranged on the segmented capacitance polar plate I, a plurality of capacitance electrodes II are arranged on the segmented capacitance polar plate II, the capacitance electrodes I and the capacitance electrodes II are arranged oppositely, and the capacitance electrodes I on the segmented capacitance polar plate I and the capacitance electrodes II of the segmented capacitance polar plate II form a plurality of segmented capacitances. The multiphase layered liquid level interface measurement system is based on the sensor. The invention can solve the problems that the prior capacitance sensor is easy to accumulate crude oil and the electrode plate needs to be reliably sealed.

Description

A Segmented Capacitance Sensor and Multiphase Layered Liquid Level Interface Measurement System

technical field

The invention relates to the field of capacitive liquid level measurement, in particular to a segmented capacitive sensor and a multiphase layered liquid level interface measurement system based on the segmented capacitive sensor.

Background technique

The oil extracted from the oil field is a three-phase mixture of oil, gas, and water, and the extraction process is accompanied by the existence of sediment. Normally, from the top of the tank to the bottom of the tank, there are crude oil, oil-water emulsion, water, and sludge layer in sequence. In the process of oil extraction, various links such as transfer tanks, settling tanks, crude oil dehydrators, electric extractors, buffer tanks, storage and transportation tanks, etc. need multi-phase liquid level measurement, which is convenient for oil and water separation control, and for the control of production In the process, the water content of crude oil and crude oil production provide data.

At present, there are many research methods for oil-water level measurement at home and abroad, and the most researched method is the segmental capacitive measurement method. The method based on the segmental capacitance is mainly based on the principle that the change of the dielectric causes the change of the capacitance, and the measured capacitance value has a linear relationship with the interface. A single capacitor cannot distinguish between oil and water, oil and gas, and emulsified multiphase interfaces. For the measurement of crude oil multiphase interface, segmented capacitive sensors are mainly used. The segmented capacitive sensor can distinguish whether each capacitor is in water, crude oil, emulsified zone or air according to the value of each capacitor, and then calculate and distinguish the multiphase interface. Segmented capacitive sensors have high measurement accuracy and low cost, and are the most widely studied.

There are three main layout forms of commonly used segmented capacitor electrodes:

1. Symmetrical bipolar plate segmented capacitor structure, the two plates of each capacitor are symmetrical and have the same parameters;

2. Segmented capacitor structure with common electrodes;

3. Unipolar segmented capacitor structure. This scheme uses the tank body of the crude oil tank as the common electrode of the segmented capacitor.

The height of crude oil storage tanks is usually high, generally more than 10 meters. In order to improve the accuracy of liquid level measurement as much as possible, the measurement scheme of segmental capacitance measurement is adopted. The number of capacitances is generally dozens, and may even be as many as hundreds. At present, the main problems faced by the scheme of measuring oil-water, emulsified zone, and oil-gas interface in crude oil tanks based on segmental capacitance are as follows:

Most current segmented capacitance measurement solutions place the circuitry that measures capacitance outside the tank. Because of the large number of segmented capacitors, a large number of leads must be drawn out to the measurement circuit, which brings difficulties to the installation and maintenance of the measurement system. In addition, the capacitor leads are long, the parasitic capacitance value is large, and the lengths of different capacitor leads are different, which brings great inconvenience to measurement and data processing.

In the measurement process of relatively dirty liquids such as crude oil, if the PTFE material is not used, the surface of the segmented capacitance sensor is easy to hang oil, which will cause the capacitance value to gradually shift and affect the measurement accuracy. Polytetrafluoroethylene has good anti-sticking properties, and as an insulating material, it can better solve the problem of oil hanging. However, almost all glue bonding cannot firmly bond PTFE, which brings sealing problems to segmented capacitive sensors based on PTFE materials.

In order to realize the sealing of the sensor, most of them use polytetrafluoroethylene or polyperfluoroethylene propylene round tube as the sheath of the electrode. Place segmented capacitor plates in polytetrafluoroethylene or polyfluoroethylene propylene tubes, connect each segmented capacitor electrode to the measurement circuit through lead wires, and segmented capacitor plates are made into rings.

At present, most products use the crude oil tank as another electrode of the capacitor, and the arrangement of the electrodes is a single-pole segmented capacitor structure. This type of sensor has two disadvantages: First, the shape of the tank and the position of the sensor will affect the sensor parameters, so the sensor parameters of this structure need to be calibrated on site. Second, due to the large diameter of the tank, the accuracy of the sensor is affected by using the tank body as the electrode. If the inner wall of the tank is made of non-metallic materials, accurate measurement cannot be achieved.

There are also research programs that propose adding a stainless steel tube to the round tube as another electrode of the capacitor. The diameter of the stainless steel tube is larger than that of the polytetrafluoroethylene tube, and it is coaxial with the polytetrafluoroethylene tube. Its structure belongs to a segment capacitor with a common electrode. The disadvantage of using polytetrafluoroethylene tubes to process segmented capacitance sensors is that when the tank body is large and there are many segmented capacitors, the electrodes of each segmented capacitor must be connected to the external measurement line. This scheme has more wiring harnesses. Moreover, the wiring harness is very long, which is very unfavorable for processing and production and product calibration.

Contents of the invention

The technical problem to be solved by the present invention is to provide a segmented capacitive sensor and a multi-phase layered liquid level interface measurement system, which can solve the problems that the existing capacitive sensors are easy to accumulate crude oil and the electrode plates need to be reliably sealed.

In order to solve the technical problem, the technical solution adopted in the present invention is: a segmented capacitive sensor, comprising a plurality of sensor nodes, each sensor node including a segmented capacitor plate I, a segmented capacitor plate I signal transfer Board, segmented capacitance detection circuit, segmented capacitor plate I shell, segmented capacitor plate II, segmented capacitor plate II signal adapter board, segmented capacitor plate II shell, power supply and communication lines, segmented capacitor The plate I is placed parallel to the segmented capacitor plate II, the segmented capacitor plate I is provided with a plurality of capacitor electrodes I, and the segmented capacitor plate II is provided with a plurality of capacitor electrodes II, and the capacitor electrode I is arranged opposite to the capacitor electrode II , and the capacitive electrode I and the capacitive electrode II are the same in number, size, and arrangement position, the capacitive electrode I and the capacitive electrode II at the same position form a parallel plate capacitance, and the capacitive electrode I on the segmental capacitive plate I is connected to the segment The capacitor electrode II of the capacitor plate II forms a plurality of segmented capacitors;

The segmented capacitor plate I, the segmented capacitor plate I signal adapter plate, and the segmented capacitor detection circuit are packaged in the segmented capacitor plate I shell, and the capacitor electrode I is connected to the Segment capacitance detection circuit;

Segmented capacitor plate II and segmented capacitor plate II signal adapter board are packaged in the shell of the segmented capacitor plate II, and the capacitor electrode II is connected to the segmented capacitance detection through the segmented capacitor plate II signal adapter board and leads circuit;

The power supply and communication lines are connected to the segmented capacitance detection circuit, and the power supply and communication lines are drawn from the inside of the segmented capacitor plate I shell to the outside of the segmented capacitor plate I shell, and the power supply and communication lines realize the cascading of multiple sensor nodes and Connection of sensor nodes to the bus.

Further, the segmented capacitor plate I shell includes a housing I, and the segmented capacitor plate 1 includes a capacitor electrode I distribution area and a shielding area I, and the capacitor electrode I distribution area is arranged at the center of the segmented capacitor plate 1, and the shielding area I surrounds the distribution area of the capacitor electrode I, the shell I has an opening on one side, and the shielding area I of the segmented capacitor plate I is welded at the opening of the shell I.

Further, the section capacitor plate I shell also includes a return-shaped frame I, and the return-shaped frame I is welded on the shielding area I of the segment capacitor plate 1, and the segment capacitor plate I welded with the return-shaped frame I passes through the bolt It is fixed at the opening of the casing I, and a sealing gasket is provided between the segment capacitor plate I and the casing I.

Further, the capacitor electrode 1 is welded on the front of the segmented capacitor plate 1, the segmented capacitor plate 1 signal adapter plate and the segmented capacitor detection circuit are welded on the back side of the segmented capacitor plate 1, and the housing 1 is provided with The glue injection port, after the segmented capacitor plate I is connected to the housing I, fills the housing I with sealant through the glue injection port.

Further, the shell of the segmented capacitor plate II includes a housing II, and the segmented capacitor plate II includes a distribution area of the capacitor electrode II and a shielding area II, and the distribution area of the capacitor electrode II is arranged in the center of the segmented capacitor plate II, and the shielding area II surrounds the distribution area of the capacitor electrode II, the shell II is open on one side, and the shielding area II of the segmented capacitor plate II is welded at the opening of the shell II.

Further, the segmented capacitor plate II housing also includes a return-shaped frame II, which is welded on the shielding area II of the segmented capacitor plate II, and the segmented capacitor plate II welded with the return-shaped frame II is passed through a bolt It is fixed at the opening of the casing II, and a sealing gasket is provided between the segment capacitor plate II and the casing II.

Further, the capacitor electrode II is welded on the front of the segmented capacitor plate II, and the signal adapter plate of the segmented capacitor plate II is welded on the back of the segmented capacitor plate II, and the casing II is provided with a glue injection port. After the capacitor plate II is connected to the shell II, the sealant is filled into the shell II through the glue injection port.

Further, the material of the casing of segmented capacitor plate I and the shell of segmented capacitor plate II is metal.

Further, the segmented capacitor plates I and the segmented capacitor plates II are one of FR-4 plates, aluminum substrates, and polytetrafluoroethylene circuit boards.

Further, the segmented capacitor plate I and the segmented capacitor plate II are polytetrafluoroethylene circuit boards, and the polytetrafluoroethylene boards are laminated boards made of polytetrafluoroethylene material and copper foil.

The invention also discloses a multi-phase layered liquid level interface measurement system, including a liquid level interface sensor, a bus, a bus communication interface and a monitoring host, the liquid level interface sensor is the above-mentioned segmented capacitance sensor, and multiple sensors of the segmented capacitance sensor The nodes are placed in the crude oil storage tank and distributed along the height direction of the crude oil storage tank; multiple sensor nodes of the segmented capacitive sensor are connected to the bus communication interface through the bus, and the bus communication interface is connected to the monitoring host.

Beneficial effects of the present invention: segmental capacitance is divided into multiple nodes, the measurement circuit is sealed inside the sensor node, the capacitance signal is converted into a digital signal and output to the communication bus, a large number of wiring harnesses are reduced, and the measurement wiring harness is avoided to be connected to the outside, so that The measurement data is more stable and reliable.

The adopted structure and bus communication form enable the sensor nodes to be freely increased according to the height of the tank. The processing, production and installation of the sensor are very convenient.

The sensor uses a polytetrafluoroethylene plate (not a tube) as an insulating layer, and the polytetrafluoroethylene and copper foil are pressed together. The polytetrafluoroethylene can solve the problem of oil hanging on the surface of the sensor.

Structurally, the sensor solves the problem that the polytetrafluoroethylene plate (note: not the polytetrafluoroethylene tube solution) is difficult to seal, and the bipolar plate segmented capacitance measurement scheme constituted has higher accuracy than the unipolar plate scheme. Inside the sensor, the polytetrafluoroethylene segmented capacitor plate and the detection circuit board use adapter plate leads. The lead wire connection is reliable, the processing is simple and the cost is low.

Description of drawings

Fig. 1 is a schematic structural diagram of a single sensor node;

Fig. 2 is a schematic diagram of the external structure of a single sensor node;

Fig. 3 is a schematic diagram of an explosion structure of a single sensor node;

Fig. 4 is the structural representation of segmented capacitance plate 1;

Fig. 5 is the schematic diagram of segment capacitor plate I signal adapter plate;

Fig. 6 is a functional block diagram of the liquid level interface measurement system;

Among the figure: 1. Segmented capacitor plate I, 2. Segmented capacitor plate I signal adapter plate, 3. Segmented capacitance detection circuit, 4. Segmented capacitor plate I shell, 5. Segmented capacitor plate II, 6. Segmented capacitor plate II signal adapter board, 7. Segmented capacitor plate II shell, 8. Capacitor electrode I, 9. Capacitor electrode II, 10. Power supply and communication lines, 13. Distribution of capacitor electrode I Area, 14, shielding area I, 15, round hole, 16, copper foil, 17, pad, 18, gasket I, 19, return frame I, 20, detection circuit insulating gasket, 21, return form II , 22, Gasket II.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Example 1

The present embodiment discloses a segmented capacitive sensor, comprising a plurality of sensor nodes, as shown in Figures 1, 2, and 3, each sensor node includes a segmented capacitor plate I 1, a segmented capacitor plate I signal Adapter board 2, segmented capacitance detection circuit 3, segmented capacitor plate I shell 4, segmented capacitor plate II 5, segmented capacitor plate II signal adapter plate 6, segmented capacitor plate II shell 7, Power supply and communication line 10.

The segment capacitor plate I 1 is placed in parallel with the segment capacitor plate II 5, the segment capacitor plate I 1 is provided with a plurality of capacitor electrodes I 8, and the segment capacitor plate II 5 has a plurality of capacitor electrodes II 9, Capacitive electrode I 8 is set opposite to capacitive electrode II 9, and capacitive electrode I 8 and capacitive electrode II 9 are all the same in number, size, and arrangement position, and capacitive electrode I 8 and capacitive electrode II 9 at the same position form a parallel plate capacitance , the capacitor electrode I 8 on the segment capacitor plate I 1 and the capacitor electrode II 9 on the segment capacitor plate II 6 form a plurality of segment capacitors. The space between the segmented capacitor plate I1 and the segmented capacitor plate II5 is called a dielectric space.

Segmented capacitor plate I1, segmented capacitor plate I signal adapter plate 2, and segmented capacitor detection circuit 3 are packaged in the segmented capacitor plate I shell 4, and the capacitor electrode I8 is transferred through the segmented capacitor plate I signal The board 2 is connected to a segment capacitance detection circuit 3 .

Segmented capacitor plate II5 and segmented capacitor plate II signal adapter plate 6 are packaged in the segmented capacitor plate II shell 7, and capacitor electrode II9 is connected to the branch through the segmented capacitor plate II signal adapter plate 6 and leads. Segment capacitance detection circuit 3. In this embodiment, the lead wires connected between the segmented capacitance plate II signal adapter plate 6 and the segmented capacitance detection circuit 3 are multi-core shielded wires, and multiple electrodes on the segmented capacitor plate II5 utilize multi-core shielding. The line is connected to the capacitance detection circuit in the shell 4 of the segmented capacitor plate II through the lead wire interface of the segmented capacitor plate II.

The power supply and the communication line 10 are connected to the segment capacitance detection circuit 3, and the power supply and the communication line 10 are drawn from the inside of the segment capacitor pole plate 1 shell 4 to the outside of the segment capacitor pole plate 1 shell 4, and the power supply and the communication line 10 realize multiple Cascading of sensor nodes and connection of sensor nodes to the bus. As shown in Figures 2 and 3, the power supply and communication line 10 of this embodiment includes a first power supply and communication line 11 and a second power supply and communication line 12, one of which is used to connect the power supply and the bus, and the other is used to connect the power supply The power supply and the bus are connected to the next sensor node to facilitate the cascading of each sensor node. It is also possible to use cascadable connectors to realize the cascading of nodes, and at this time, the sensor nodes only need a power communication line.

The segment capacitor plate 1 shell includes a housing 1, and as shown in Figure 4, the segment capacitor plate 1 includes a capacitor electrode I distribution area 13 and a shielding area I14, and the capacitor electrode I distribution area 14 is arranged on the segment capacitor electrode plate 1 In the center, the shielding area I14 surrounds the capacitor electrode I distribution area 13, the housing I is open on one side, and the shielding area I14 of the segmented capacitor plate I is welded at the opening of the housing I. On the one hand, the shielding area I14 plays the role of shielding external interference, and on the other hand, it is connected with the housing I by soldering, which has high connection strength and good sealing performance. The circular holes 15 are fixed mounting holes, and the number of the fixed mounting holes 15 can be increased or decreased according to the actual situation. If the surrounding metal shielding layer is well welded to the metal shell, no fixed mounting holes can be added at this time.

Setting the fixed installation hole is in order to make the connection more firm, and as shown in Figure 3, segmented capacitor pole plate 1 shell 4 also includes loop-shaped frame I19, and loop-shaped frame I19 is welded on the shielding area I14 of segmented capacitor polar plate 1, The segmented capacitor plate I1 welded with the circular frame I19 is fixed at the opening of the shell I by bolts, and a gasket I18 is arranged between the segmented capacitor plate I1 and the shell I. As shown in Figure 5, the capacitor plate 1 signal adapter plate 2 can be bonded to the segmented capacitor plate, and the block on the adapter circuit board is a copper foil 16 smaller in size than the capacitor electrode, which is pasted on the capacitor substrate Used to increase contact area. The circular part in the box is a pad 17 with a round hole, and the pad 17 is welded to the capacitor electrode by soldering, and all the capacitor electrodes are transferred to an interface that is easier to wire or connect to a segmented capacitance detection circuit through a signal adapter board.

The capacitor electrode I8 is welded on the front of the segmented capacitor plate I1, and the segmented capacitor plate I signal adapter plate 2 is attached to the back of the segmented capacitor plate I1, and the assembled segmented capacitor plate I1 and the segmented capacitor The plate I signal adapter plate 2 is connected to the segmented capacitance detection circuit 3 through a connector or a lead wire, and the housing I is provided with a glue injection port. After the segmented capacitor plate I1 is connected to the housing I, it is Mouth is filled with sealant in housing 1.

In this embodiment, the front side of the segmented capacitor plate I1 refers to the side of the segmented capacitor plate I1 facing the dielectric space, and the back side of the segmented capacitor plate I1 refers to the side of the segmented capacitor plate I towards the inside of the housing I. one side.

Equally, the subsection capacitor plate II housing 7 includes the housing II, and the subsection capacitor panel II5 includes the distribution area of the capacitance electrode II and the shielding area II, and the distribution area of the capacitance electrode II is arranged at the center of the section capacitance plate II, shielding The area II surrounds the distribution area of the capacitor electrode II, the housing II is open on one side, and the shielding area II of the segmented capacitor plate II is welded at the opening of the housing II.

The shell of the segmented capacitor plate II also includes a return-shaped frame II21, which is welded on the shielding area II of the segmented capacitor plate II5, and the segmented capacitor plate II5 welded with the return-shaped frame II21 is fixed on the shell by bolts. At the opening of the body II, a gasket II22 is provided between the segment capacitor plate II and the casing II.

The capacitor electrode II9 is welded on the front of the segmented capacitor plate II5, the segmented capacitor plate II signal adapter plate 6 is pasted on the back of the segmented capacitor plate II5, the shell II is provided with a glue injection port, and the segmented capacitor electrode After the plate II5 is connected to the shell II, the sealant is filled into the shell II through the injection port.

The front of the segmented capacitor plate II5 refers to the side of the segmented capacitor plate II5 facing the dielectric space, and the back of the segmented capacitor plate II5 refers to the side of the segmented capacitor plate II5 facing inside the housing II.

In this embodiment, the shells of the segmented capacitor plate I and the shell of the segmented capacitor plate II are made of metal, which can shield external interference signals.

The segmented capacitor plate I1 and the segmented capacitor plate II5 are one of FR-4 plates, aluminum substrates, and polytetrafluoroethylene circuit boards.

Specifically, the segmented capacitor plate I1 and the segmented capacitor plate II5 are polytetrafluoroethylene circuit boards, and the polytetrafluoroethylene board is made of polytetrafluoroethylene material and copper foil laminated board, which undergoes the same etching method as the PCB circuit board It is processed with high precision.

In order to prevent corrosion and prevent the measured liquid level from affecting the measured value of the capacitance, the capacitance electrode must be reliably insulated and sealed. If the insulating material is polytetrafluoroethylene (or polytetrafluoroethylene-based materials, such as a mixture of polytetrafluoroethylene and glass fiber), it can prevent the sensor from being corroded and can avoid oil accumulation. However, the problem with using polytetrafluoroethylene as segmented capacitor plates is that polytetrafluoroethylene is extremely non-sticky, and it is almost impossible to stick together firmly with any glue, making it difficult to seal the sensor, especially for parallel plate sensors . The segmented capacitance sensor described in this embodiment is a parallel plate sensor with a simple structure, but it uses polytetrafluoroethylene as the segmented capacitor plate, and the segmented capacitor plate is welded or fixed on the sensor shell by bolts, which solves the problem of The problem of the sensor being corroded caused by the hanging oil can also ensure the sealing reliability of the sensor.

Example 2

This embodiment discloses a multi-phase layered liquid level interface measurement system, as shown in Figure 6, including a liquid level interface sensor, a bus, a bus communication interface and a monitoring host, and the liquid level interface sensor is the segmented capacitor described in Embodiment 1 Sensors, multiple sensor nodes of the segmented capacitance sensor are placed in the crude oil storage tank, distributed along the height direction of the crude oil storage tank; multiple sensor nodes of the segmented capacitance sensor are connected to the bus communication interface through the bus, and the bus communication interface and monitoring The host is connected, and the monitoring host analyzes the height of oil, water and oil-water mixture in the tank according to the received capacitance data.

The segmental capacitance detection circuit can detect all the segmental capacitances of the node and convert the capacitance data into digital signals. The segmented capacitance detection circuit sends the digital signal to the outside through the communication bus, and the bus can be CAN bus, RS-485 bus, etc. All nodes in the system can be connected to the bus, so the external wiring of the whole system only needs power supply positive, power supply negative, communication bus, and common plate leads. According to different capacitance detection circuits, the common plate lead can also be connected to the negative pole of the power supply .

The above descriptions are only the basic principles and preferred embodiments of the present invention. Improvements and replacements made by those skilled in the art according to the present invention belong to the protection scope of the present invention.

Claims (9)

1. A segmented capacitive sensor, characterized in that: comprise segmented capacitor pole plate 1, segmented capacitor polar plate 1 signal adapter plate, segmented capacitor detection circuit, segmented capacitor polar plate 1 shell, segmented capacitor pole Plate II, segmented capacitor plate II signal adapter board, segmented capacitor plate II casing, power supply and communication lines, segmented capacitor plate I and segmented capacitor plate II are placed in parallel, and segmented capacitor plate I is placed There are a plurality of capacitance electrodes I, and a plurality of capacitance electrodes II on the segmented capacitance plate II, the capacitance electrodes I and the capacitance electrodes II are arranged oppositely, and the capacitance electrodes I and the capacitance electrodes II are the same in number, size, and arrangement position, The capacitance electrode I and the capacitance electrode II at the same position form a parallel plate capacitance, and the capacitance electrode I on the segment capacitance plate I and the capacitance electrode II of the segment capacitance electrode II form a plurality of segment capacitances; The segmented capacitor plate I, the segmented capacitor plate I signal adapter plate, and the segmented capacitor detection circuit are packaged in the segmented capacitor plate I shell, and the capacitor electrode I is connected to the Segment capacitance detection circuit; Segmented capacitor plate II and segmented capacitor plate II signal adapter board are packaged in the shell of the segmented capacitor plate II, and the capacitor electrode II is connected to the segmented capacitance detection through the segmented capacitor plate II signal adapter board and leads circuit; The power supply and the communication line are connected to the segmented capacitance detection circuit, and the power supply and the communication line are drawn from the inside of the segmented capacitor plate I shell to the outside of the segmented capacitor plate I shell; The power supply and communication lines realize the connection of sensor nodes to the bus, and can realize the cascade connection of multiple sensor nodes to form more segmental capacitance measurement systems; The shell of the segmented capacitor plate I includes a housing I, and the segmented capacitor plate I includes a distribution area of the capacitor electrode I and a shielding area I. The distribution area of the capacitor electrode I is arranged at the center of the segmented capacitor plate I, and the shielding area I surrounds the Around the distribution area of the capacitor electrode I, the shell I has an opening on one side, and the shielding area I of the segmented capacitor plate I is welded at the opening of the shell I; the shell of the segmented capacitor plate II includes the shell II, and the segmented capacitor plate II includes the capacitor electrode II distribution area and the shielding area II. The capacitor electrode II distribution area is set in the center of the segmented capacitor plate II, and the shielding area II surrounds the capacitor electrode II distribution area. The shell II is open on one side, and the segmented capacitor The shielding area II of the pole plate II is welded at the opening of the shell II. 2. segmental capacitive sensor according to claim 1, is characterized in that: segmented capacitor pole plate 1 shell also comprises loop-shaped frame 1, and loop-shaped frame 1 is welded on the shielding area 1 of segmented capacitor polar plate 1, The segmented capacitor plate I welded with the circular frame I is fixed at the opening of the shell I by bolts, and a gasket is provided between the segmented capacitor plate I and the shell I. 3. The segmented capacitive sensor according to claim 1 or 2, characterized in that: the capacitor electrode 1 is welded on the front of the segmented capacitor plate 1, and the segmented capacitor plate 1 signal adapter plate is attached to the segmented capacitor pole On the back side of the plate I, the segmented capacitor plate I and the segmented capacitor plate I signal adapter plate assembled together are connected to the segmented capacitor detection circuit through a connector or a lead wire, and the shell I is provided with a glue injection port. After the segmented capacitor plate I is connected to the casing I, the casing I is filled with sealant through the glue injection port. 4. segmental capacitive sensor according to claim 1, is characterized in that: segmental capacitor polar plate II housing also comprises return-shaped frame II, and return-shaped frame II is welded on the shielding area II of segmental capacitor polar plate II, The segmented capacitor plate II welded with the circular frame II is fixed to the opening of the shell II by bolts, and a sealing gasket is provided between the segmented capacitor plate II and the shell II. 5. The segmented capacitance sensor according to claim 1 or 4, characterized in that: the capacitance electrode II is welded on the front of the segmented capacitor plate II, and the segmented capacitor plate II signal adapter plate is attached to the segmented capacitor pole On the back of the plate II, there is a glue injection port on the shell II. After the segmented capacitor plate II is connected to the shell II, the sealant is filled into the shell II through the glue injection port. 6. The segmented capacitive sensor according to claim 1, characterized in that: the segmented capacitive plate I shell and the segmented capacitive plate II shell are made of metal. 7. The segmented capacitive sensor according to claim 1, characterized in that: the segmented capacitor plate I and the segmented capacitor plate II are one of FR-4 plates, aluminum substrates, and polytetrafluoroethylene circuit boards . 8. The segmented capacitance sensor according to claim 7, characterized in that: the segmented capacitor pole plate I and the segmented capacitor pole plate II are polytetrafluoroethylene circuit boards, and the polytetrafluoroethylene plate is a polytetrafluoroethylene material A plate formed by high temperature pressing with copper foil. 9. A multi-phase layered liquid level interface measurement system, characterized in that: comprising a liquid level interface sensor, a bus, a bus communication interface and a monitoring host, the liquid level interface sensor is a segmented capacitive sensor as claimed in claim 1, and the segmented The multiple sensor nodes of the capacitive sensor are placed in the crude oil storage tank and distributed along the height direction of the crude oil storage tank; the multiple sensor nodes of the segmented capacitive sensor are connected to the bus communication interface through the bus, and the bus communication interface is connected to the monitoring host.

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