Single-stage capacitive low-temperature liquid level sensor

Abstract

The utility model relates to the technical field of sensors, and discloses a single-stage capacitive low-temperature liquid level sensor which comprises a detection head and a connector located at one end of the detection head, and a first crown spring wire pressing terminal and a second crown spring wire pressing terminal are installed in the detection head and the connector respectively. The same glass terminal is installed between the first crown spring wire pressing terminal and the second crown spring wire pressing terminal, an upper plug is installed at one end of the second crown spring wire pressing terminal, an inner pipe extending to the outside of the detection head is installed at the end of the upper plug, and a sealing pipe is installed between the inner pipe and the connector. The sealing pipe is arranged between the connector and the inner pipe, and the sealing pipe is used for sealing the gap between the connector and the inner pipe, so that the condition that the detected low-temperature liquid is in contact with the glass terminal to cause damage is reduced; a third sealing plug is arranged on the sealing pipe in a sleeving mode, and the sealing effect is further achieved through the third sealing plug.

Description

TECHNICAL FIELD

[0001] The utility model relates to sensor technical field, concretely is a single stage capacitive cryogenic liquid level sensor. BACKGROUND

[0002] In modern industrial production, instruments and meters are important tools for detecting the operating conditions of equipment, and liquid level meters, as instruments for measuring the level of liquid medium in a container, play an irreplaceable role. Current liquid level meters are mainly divided into magnetic floating type, pressure type, ultrasonic type, etc. However, these types of liquid level meters have defects such as insufficient measurement accuracy, complex structure, and high price, which cannot meet the needs of modern industrial production. Therefore, in recent years, a new type of capacitive liquid level meter has emerged. The working principle of the capacitive liquid level meter is to convert the position change of the measured object into capacitance for measurement.

[0003] During use of the capacitive liquid level sensor, the lower detection part usually extends into the liquid for liquid level detection. However, the sealing effect of the capacitive liquid level sensor on the market is poor. Over a long period of use, the detected liquid can enter the connector from the gap between the inner tube and the connector, causing damage to the electronic components inside the capacitive sensor.

[0004] Therefore, we propose a single stage capacitive cryogenic liquid level sensor to solve the above problems. UTILITY MODEL CONTENTS

[0005] The utility model aims to solve the above technical problems.

[0006] To achieve the above purpose, the utility model adopts the following technical scheme: a single stage capacitive cryogenic liquid level sensor, comprising a detection head and a connector located at one end of the detection head, the inner parts of the detection head and the connector are respectively provided with a first crown spring pressure wire terminal and a second crown spring pressure wire terminal, the same glass terminal is installed between the first crown spring pressure wire terminal and the second crown spring pressure wire terminal, one end of the second crown spring pressure wire terminal is provided with an upper plug, the end of the upper plug is provided with an inner tube extending to the outside of the detection head, a sealing tube is installed between the inner tube and the connector, the inner tube outside the detection head is sleeved on the outer tube, a plurality of detection holes are respectively sleeved on the inner tube and the outer tube, and a detection cavity for detecting the liquid level is formed between the inner tube and the outer tube.

[0007] Further, a nut is threadedly installed at one end of the connector close to the detection head, a "ring"-shaped pressing plate is fixed at one end of the nut, and a "ring"-shaped protrusion is arranged on the outer surface of the glass terminal between the pressing plate and the connector.

[0008] Further, the first crown spring wire pressing terminal is screwed in the first sealing plug, and the first sealing plug is fixedly connected with the inner side wall of the connector.

[0009] Further, one end of the connector is provided with a placing groove for storing a detection element, and a sealing cover is screwed on the opening of the placing groove; the placing groove is provided with a cable outlet extending to the outside of the detection head, and a fixing head for fixing the cable is screwed on the cable outlet, and a rubber pad is arranged in the cable outlet and matched with the fixing head.

[0010] Further, the inner side wall of the connector is provided with an integrally-formed extrusion sleeve, and the sealing tube is located between the extrusion sleeve and the inner tube.

[0011] Further, the second crown spring wire pressing terminal is inserted into the second sealing plug, and a clamping piece fixed on the end of the sealing tube is extruded between the second sealing plug and the extrusion sleeve.

[0012] Further, one end of the outer tube is fixedly connected with a mounting seat, and the mounting seat is screwed in the connector.

[0013] Further, a third sealing plug is arranged in the connector between the extrusion sleeve and the mounting seat, and the third sealing plug is sleeved on the extrusion sleeve.

[0014] Further, the tail end of the inner tube is provided with a sealing head in the outer tube, and the tail end of the outer tube is provided with a lower plug.

[0015] The utility model discloses beneficial effects:

[0016] The utility model discloses that the sealing tube is arranged between the connector and the inner tube, and the sealing tube plays the role of sealing the gap between the connector and the inner tube, reduces the damage caused by the contact between the low-temperature liquid to be detected and the glass terminal, the third sealing plug is sleeved on the sealing tube, and the third sealing plug further plays the role of sealing, avoids the contact between the low-temperature liquid to be detected and the electronic element through the gap between the sealing tube and the connector, the clamping piece is arranged on one end of the sealing tube, and when the second sealing plug moves to the extrusion sleeve, the clamping piece can be sealed, and the sealing effect is achieved again, the contact between the low-temperature liquid to be detected and the electronic element through the gap between the sealing tube and the inner tube is avoided, thereby having good sealing effect, reducing the damage caused by the contact between the electronic element and the low-temperature liquid, and prolonging the service life of the sensor. DRAWINGS

[0017] Figure 1 It is the three-dimensional structure schematic diagram of the utility model;

[0018] Figure 2is the explosion structure schematic view of the utility model (not including inner tube and outer tube);

[0019] Figure 3 is the section structure schematic view of the utility model;

[0020] Figure 4 is the local section structure schematic view of the utility model;

[0021] Figure 5 is the explosion structure schematic view of the utility model (including detection head, cable outlet, fixed head and rubber pad).

[0022] The name corresponding to each mark in the drawing is:

[0023] 1, detection head;2, connecting head;3, first crown spring press wire terminal;4, second crown spring press wire terminal;5, glass terminal;6, upper plug;7, inner tube;8, outer tube;9, detection hole;10, detection cavity;11, nut;12, pressing plate;13, protrusion;14, first sealing plug;15, placing groove;16, sealing cover;17, cable outlet;18, fixed head;19, rubber pad;20, extrusion sleeve;21, sealing tube;22, second sealing plug;23, clamping piece;24, mounting seat;25, third sealing plug;26, sealing head;27, lower plug. DETAILED DESCRIPTION

[0024] The technical scheme in the embodiments of the utility model will be described clearly and completely below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art belong to the scope of protection of the utility model.

[0025] A single-stage capacitive low-temperature liquid level sensor, detection head 1 and connecting head 2 located at one end of detection head 1;

[0026] As Figure 3The inside of the detection head 1 is provided with a placing groove 15, and the inside of the placing groove 15 stores a detection element (not shown in the figure), and the detection element is a capacitive sensing chip with a model of MDC04; a sealing cover 16 is threadedly installed at the opening of the placing groove 15, and the sealing cover 16 is provided to close the placing groove 15; prevent the detection element from falling from the inside of the placing groove 15; it should be noted that the outer surface of the detection head 1 is provided with a cable outlet 17 which communicates with the placing groove 15; through the setting of the cable outlet 17, the power line of the detection element can be extended to the outside of the detection head 1; the inner side wall of the cable outlet 17 is fixed with a "ring"-shaped partition (not shown in the figure), and the partition is provided with a rubber pad 19 on one side, and the rubber pad 19 is a butyronitrile rubber pad. If the rubber pad 19 is sleeved on the power line of the detection element, the fixing head 18 is threadedly rotated in the cable outlet 17, so as to apply pressure to the rubber pad 19, thereby sealing the cable outlet 17; avoid the liquid from the outside entering the inside of the placing groove 15 through the cable outlet 17, causing the damage of the detection element.

[0027] A glass terminal 5 is arranged between the detection head 1 and the connecting head 2; in detail: one end of the glass terminal 5 is inserted into the first crown spring pressure wire terminal 3; and the first crown spring pressure wire terminal 3 is electrically connected with the detection element, the first crown spring pressure wire terminal 3 is threadedly installed in the inside of the first sealing plug 14, and the first sealing plug 14 is fixed to the inner side wall of the detection head 1, the first sealing plug 14 is provided to seal the detection head 1, to reduce the liquid from the outside entering the inside of the detection head 1, causing the damage of the glass terminal 5 or the first crown spring pressure wire terminal 3; the other end of the glass terminal 5 is inserted into the inside of the second crown spring pressure wire terminal 4; and the second crown spring pressure wire terminal 4 is located in the inside of the connecting head 2; it should be noted that a second sealing plug 22 is arranged between the connecting head 2 and the second crown spring pressure wire terminal 4, and the second sealing plug 22 is provided to seal the connecting head 2, to reduce the liquid from the outside entering the inside of the connecting head 2, causing the damage of the second crown spring pressure wire terminal 4 or the glass terminal 5.

[0028] A nut 11 is threadedly installed at one end of the connecting head 2 close to the detection head 1, and a "ring"-shaped pressing plate 12 is fixed to one side of the nut 11; a "ring"-shaped protrusion 13 is arranged between the pressing plate 12 and the connecting head 2 and fixed to the outer surface of the glass terminal 5; it should be noted that the hole diameter of the pressing plate 12 is smaller than the outer diameter of the protrusion 13; during the screw rotation of the nut 11, the pressing plate 12 can be moved and pressed against the protrusion 13, thereby achieving the function of fastening, preventing the glass terminal 5 from loosening during use; improving the stability of the liquid level sensor.

[0029] One end of the second crown spring crimping terminal 4 is provided with an upper plug 6, and the upper plug 6 is made of 304 stainless steel material; so that the upper plug 6 has good conductivity; through the setting of the upper plug 6, on the one hand, it plays a role of conduction, which can ensure the detection of the liquid level; on the other hand, it plays a role of sealing, which avoids the contact between the detected low-temperature liquid (the low-temperature liquid can be liquid nitrogen) and the second crown spring crimping terminal 4; one end of the upper plug 6 is fixedly provided with an inner tube 7, the inner tube 7 is a negative electrode, and one end of the inner tube 7 extends to the outside of the connecting head 2, the inner tube 7 located outside the connecting head 2 is sleeved with an outer tube 8; the outer tube 8 is a positive electrode; it should be noted that the inner tube 7 and the outer tube 8 are also made of stainless steel material; they have good conductivity; the outer surfaces of the inner tube 7 and the outer tube 8 are respectively provided with a plurality of detection holes 9; through the setting of the detection holes 9, the detected low-temperature liquid can flow into a detection cavity 10 between the inner tube 7 and the outer tube 8 through the detection holes 9, and the detection cavity 10 is a capacitor; as the liquid level of the low-temperature liquid in the container continues to change, the capacitance value will also change; so that the liquid level can be detected; one end of the inner tube 7 is sealed with a sealing head 26; through the setting of the sealing head 26, it plays a role of fixing the inner tube 7, which prevents the inner tube 7 and the outer tube 8 from contacting; the sealing head 26 is made of insulating material; the tail end of the outer tube 8 is provided with a lower plug 27, which plays a role of plugging the inner end of the outer tube 8.

[0030] The inner side of the connecting head 2 is provided with an integrally formed extrusion sleeve 20, and a sealing tube 21 is arranged between the extrusion sleeve 20 and the inner tube 7; through the setting of the sealing tube 21, it plays a role of sealing the gap between the connecting head 2 and the inner tube 7; when the liquid level is higher than the second crown spring crimping terminal 4; the liquid level contacts the second crown spring crimping terminal 4 through the gap between the connecting head 2 and the inner tube 7; thereby playing a role of protection.

[0031] It should be noted that: one end of the extrusion sleeve 20 close to the detection head 1 is provided with an inwardly inclined slope; one side of the second sealing plug 22 close to the extrusion sleeve 20 is provided with an inverted bevel; and one end of the sealing tube 21 passes through the extrusion sleeve 20 and is provided with an outwardly inclined clamping piece 23; when the second sealing plug 22 moves towards the extrusion sleeve 20, it can apply pressure to the clamping piece 23, which can press the clamping piece 23 tightly, thereby further playing a role of sealing; preventing the measured low-temperature liquid from contacting the second crown spring crimping terminal 4 through the gap between the inner tube 7 and the sealing tube 21, thereby further playing a role of protection.

[0032] One end of the outer tube 8 is fixedly connected with a mounting seat 24, and the mounting seat 24 is screw-mounted in the inside of the connecting head 2; through the setting of the mounting seat 24, it plays a role of fixing the outer tube 8.

[0033] A third sealing plug 25 is arranged between the extrusion sleeve 20 and the mounting seat 24 in the connector 2. It is to be noted that the side of the extrusion sleeve 20 close to the outer tube 8 is also provided with an inclined slope, and the side of the third sealing plug 25 is also provided with an inverted inclined angle. A groove (not shown in the figure) is arranged on the inverted inclined angle. During the screwing rotation of the mounting seat 24, the third sealing plug 25 is pushed to move. With the continuous movement of the third sealing plug 25, the extrusion sleeve 20 continuously extrudes the third sealing plug 25, so that the inverted inclined angle of the third sealing plug 25 is deformed, and the sealing tube 21 is extruded, thereby sealing the connection between the third sealing plug 25 and the connector 2. The low-temperature liquid to be detected is prevented from contacting the second crown spring pressure wire terminal 2 through the gap between the connector 2 and the sealing tube 21, thereby achieving sealing again.

[0034] When detecting the liquid level of the ultra-low temperature, first, the inner tube 7 and the outer tube 8 of the liquid level sensor are inserted into the container to be detected. The container to be detected flows into the detection cavity 10 between the inner tube 7 and the outer tube 8. With the continuous change of the liquid level, the capacitance value between the inner tube 7 and the outer tube 8 changes. The capacitive sensing chip converts the collected capacitance value into a height signal output.

Claims

1. A single-stage capacitive cryogenic liquid level sensor, comprising a detection head (1) and a connecting head (2) at one end of the detection head (1), a first crown spring terminal (3) and a second crown spring terminal (4) are respectively installed in the inside of the detection head (1) and the connecting head (2), a same glass terminal (5) is installed between the first crown spring terminal (3) and the second crown spring terminal (4), an upper plug (6) is installed at one end of the second crown spring terminal (4), and an inner tube (7) extending to the outside of the detection head (1) is installed at the end of the upper plug (6), characterized in that: And the inner tube (7) and the connector (2) between the installation of the sealing tube (21), located in the detection head (1) outside the inner tube (7) is sleeved on the outer tube (8), the inner tube (7) and the outer tube (8) are sleeved with a plurality of detection holes (9), and the inner tube (7) and the outer tube (8) form a detection cavity (10) for detecting liquid level.

2. A single stage capacitive cryogenic liquid level sensor according to claim 1, characterized in that: The connector (2) is threadedly connected with a nut (11) at one end of the detection head (1), and the nut (11) is fixed with a "ring"-shaped pressing plate (12) at one end, and the pressing plate (12) is provided with a "ring"-shaped protrusion (13) fixed on the outer surface of the glass terminal (5).

3. A single stage capacitive cryogenic liquid level sensor according to claim 2, wherein: The first crown spring pressure line terminal (3) is threadedly connected in the first sealing plug (14), and the first sealing plug (14) is fixedly connected with the inner side wall of the connector (2).

4. A single stage capacitive cryogenic liquid level sensor according to claim 3, wherein: The connector (2) is provided with a placing groove (15) at one end for storing detection elements, and a sealing cover (16) is threadedly connected at the opening of the placing groove (15).

5. A single stage capacitive cryogenic liquid level sensor according to claim 4, wherein: The placing groove (15) is provided with a cable outlet (17) extending to the outside of the detection head (1), and a fixing head (18) is threadedly connected on the cable outlet (17) for fixing the cable.

6. A single stage capacitive cryogenic liquid level sensor according to claim 5, wherein: The inner side wall of the connector (2) is provided with an integrally formed extrusion sleeve (20), and the sealing tube (21) is located between the extrusion sleeve (20) and the inner tube (7).

7. A single stage capacitive cryogenic liquid level sensor according to claim 6, wherein: The second crown spring pressure line terminal (4) is inserted into the second sealing plug (22), and the second sealing plug (22) and the extrusion sleeve (20) are extruded with a clamping member (23) fixed on the end of the sealing tube (21).

8. A single stage capacitive cryogenic liquid level sensor according to claim 7, wherein: One end of the outer tube (8) is fixedly connected with a mounting seat (24), and the mounting seat (24) is threadedly connected in the connector (2).

9. A single stage capacitive cryogenic liquid level sensor according to claim 8, wherein: The extrusion sleeve (20) and the mounting seat (24) are provided with a third sealing plug (25) located in the connector (2), and the third sealing plug (25) is sleeved on the extrusion sleeve (20).

10. A single stage capacitive cryogenic liquid level sensor according to claim 9, wherein: The tail end of the inner tube (7) is provided with a sealing head (26) located in the outer tube (8), and the tail end of the outer tube (8) is provided with a lower plug (27).

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