A float liquid level switch

Abstract

The present invention discloses a float liquid level switch. The disclosed float liquid level switch comprises a float cavity, a sensing unit, a switch control mechanism and a magnetic isolation sleeve; the present invention adopts a float and a suction sleeve assembly to form a sensing unit, a float cavity is arranged outside the sensing unit, the float cavity and the bottom of a container in a measured device are connected to form a communicating vessel through a pipe thread, the sensing unit and the measured device are independent of each other, will not pollute the measured medium, and is easy to install; in addition, the switch control mechanism of the present invention can realize a dual-point alarm function.

Description

Technical Field

[0001] The invention relates to a liquid level control switch, in particular to a float liquid level switch for explosion-proof double-point alarm in a petrochemical environment. Background Art

[0002] The float liquid level switch is a liquid level alarm device, which is mainly used for alarm of dangerous liquid level and switch control of pump. The existing float liquid level switch has the following problems: (1) Its connecting rod mechanism has a complex structure, which is easy to get stuck during movement, resulting in insensitive response of the liquid level switch, and often no alarm or false alarm; (2) The sensor unit of the float liquid level switch needs to be directly placed in the measured liquid level cavity, which will contaminate the measured medium and is inconvenient to install. Summary of the invention

[0003] In view of the defects or shortcomings of the prior art, the present invention provides a float liquid level switch.

[0004] To this end, the float liquid level switch provided by the present invention includes a float chamber, a sensor unit, a switch control mechanism and a magnetic isolation sleeve;

[0005] The float chamber is a hollow structure, the float chamber is provided with a medium inlet at the axial bottom, a mounting interface at the top, and a medium overflow port on the side wall;

[0006] The sensing unit comprises a floating ball, a connecting rod and a suction sleeve, wherein the suction sleeve is made of a magnetic conductive material, the connecting rod is fixedly connected to the floating ball, and the suction sleeve is sleeved on the connecting rod;

[0007] The switch control mechanism includes a main mounting body, a tension spring and a permanent magnet fixing bracket;

[0008] The main mounting body is provided with a mounting through hole, and a switch mounting structure and a permanent magnet fixing bracket mounting structure are provided on the main mounting body around the mounting through hole;

[0009] One end of the permanent magnet fixing bracket is movably mounted on the permanent magnet fixing bracket mounting structure, and the other end is mounted with a permanent magnet. At the same time, a triggering member is provided on the permanent magnet bracket, and the permanent magnet faces the axial direction of the mounting through hole, and the triggering member faces the switch mounting structure. When the permanent magnet fixing bracket moves relative to the main mounting body, the permanent magnet moves away from or close to the axial direction of the mounting through hole, and the triggering member moves close to or away from the switch mounting structure.

[0010] One end of the tension spring is connected to the permanent magnet fixing bracket, and the other end is connected to an end of the main mounting body, which end is opposite to the end where the permanent magnet fixing bracket mounting structure is located; the tension spring makes the permanent magnet in a state away from the axial direction of the working through hole and the trigger member in a state close to the switch mounting structure;

[0011] A linear channel is provided in the magnetic isolation sleeve;

[0012] The magnetic isolation sleeve is fixedly connected to the mounting interface along the axial direction; the float is located in the float cavity, and the connecting rod extends out of the float cavity through the mounting interface and is located in the channel in the magnetic isolation sleeve, and the attraction sleeve is located on the connecting rod outside the float cavity and is located in the channel in the magnetic isolation sleeve; the switch control mechanism is sleeved on the magnetic isolation sleeve through the mounting through hole, and the connecting rod, the mounting through hole and the channel in the magnetic isolation sleeve are coaxial;

[0013] When the sensing unit is not acted upon by buoyancy, the attraction sleeve moves axially upward away from the switch control mechanism; when the liquid level in the float chamber rises, the float moves toward the top under the action of the buoyancy of the medium, driving the connecting rod to move upward along the channel, and when it rises to a dangerous liquid level, the tension spring is compressed under the action of the attraction sleeve and the magnetic force of the permanent magnet, and the permanent magnet fixing bracket drives the trigger member away from the switch mounting structure.

[0014] Furthermore, the switch of the present invention comprises two switch control mechanisms, and the two switch control mechanisms are sequentially sleeved on the magnetic isolation sleeve along the axial direction.

[0015] Furthermore, the wall thickness of the magnetic isolation sleeve is 2 mm, the coercive force of the attraction sleeve is 39-43 A / m, and the magnetic field strength of the permanent magnet is 2000 Gauss.

[0016] Furthermore, the connecting rod is a threaded rod, and the axial installation position of the attraction sleeve on the connecting rod is adjustable.

[0017] Furthermore, the connecting rod is a threaded rod, and the suction sleeve is threadedly connected to the connecting rod.

[0018] Furthermore, a switch mounting structure, a permanent magnet fixing bracket mounting structure and a wiring terminal mounting structure are provided on the main mounting body around the mounting through hole, and a wiring terminal fixing frame is provided at the wiring terminal mounting structure.

[0019] Furthermore, the wiring terminals are installed on the wiring terminal fixing frame.

[0020] Furthermore, the other end of the tension spring is connected to the terminal fixing frame.

[0021] Furthermore, the switch of the present invention also includes a micro switch, which is installed at the switch installation structure, and when the permanent magnet moves toward the magnetic isolation sleeve, the trigger member contacts and presses the switch key on the micro switch.

[0022] Furthermore, a threaded interface is provided at the installation interface of the float chamber, and the magnetic isolation sleeve is connected to the threaded interface via a threaded connection joint.

[0023] Furthermore, the float cavity is elliptical, and the major axis of the ellipse is the axial direction.

[0024] Furthermore, the main mounting block is Z-shaped, the working through hole is arranged on the transverse section below the Z-shaped main mounting block, the permanent magnet fixing bracket is movably installed on the vertical section of the Z-shaped main mounting block, and the transverse section above the Z-shaped main mounting block is used to limit the rotation angle of the permanent magnet fixing bracket when it moves axially away from the working through hole.

[0025] Furthermore, it also includes a shell, which is located above the float cavity, and the magnetic isolation sleeve extends into the shell. At the same time, the switch control mechanism is located in the shell, and the bottom of the shell is connected to the magnetic isolation sleeve or the float cavity; the shell is provided with wiring inlet and outlet.

[0026] Furthermore, the housing comprises an upper housing and a lower housing, the upper housing and the lower housing are threadedly connected to form the housing, and the wiring inlet and outlet are arranged on the lower housing.

[0027] The float and the suction sleeve assembly of the present invention together constitute a sensing unit, a float cavity is arranged outside the sensing unit, the float cavity and the bottom of the container in the measured device are connected to form a communicating vessel through a pipe thread, the sensing unit and the measured device are independent of each other, will not pollute the measured medium, and are easy to install. In addition, the mechanical structure of the sensing unit of the present invention is simple, and the float moves up and down smoothly without stagnation.

[0028] In a further solution, the switch control mechanism of the present invention is designed to realize a dual-point alarm function. After the low-level alarm is triggered, if the dangerous liquid level continues to rise, the high-level alarm will be triggered, forming a dual alarm, which can meet the equipment manufacturer's setting of the dangerous liquid level. When the low-level alarm occurs, the equipment can be checked in the running state, and when the high-level alarm occurs, the equipment is stopped for inspection; BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the float liquid level switch of the present invention;

[0030] Figure 2 for Figure 1 Another schematic diagram of the position of

[0031] Figure 3 This is a structural example diagram of the sensor unit of the present invention;

[0032] Figure 4 It is a structural schematic diagram of the main installation body in the switch control mechanism of the present invention;

[0033] Figure 5 It is a schematic diagram of the structure of the switch control mechanism of the present invention;

[0034] Figure 6 Another side structural example diagram of the switch control mechanism of the present invention;

[0035] Figure 7Schematic diagram of the working state of the float liquid level switch of the present invention; (a) is the initial state, (b) is the low-level alarm state; (c) is the high-level alarm state. DETAILED DESCRIPTION

[0036] Unless otherwise specified, the scientific and technical terms used herein are understood according to the knowledge of ordinary technicians in the relevant fields.

[0037] The axial, up, down, horizontal, vertical and other direction or orientation terms described in this article are consistent with the directions or orientations in the drawings of the specification. It should be noted that the specific directions or orientations in the drawings of the specification are intended to explain the clarity of the invention and do not serve as the sole limitation on the invention. Equivalent replacements, rotations, exchanges, etc. made by those skilled in the art based on the disclosure of the invention are all within the scope of protection of the invention.

[0038] like Figure 1 and 2 As shown, the float liquid level switch of the present invention comprises a float chamber 1, a sensor unit 2, a magnetic isolation sleeve 4 and a switch control mechanism 3;

[0039] The float cavity is a hollow structure that forms a cavity for accommodating the float and the medium. The axial bottom of the float cavity is provided with a medium inlet 16, the top is provided with a mounting interface 14, and the side wall between the top and the bottom is provided with a medium overflow port 15;

[0040] like Figure 3 As shown, the sensor unit 2 includes a float 21, a connecting rod 22 and a suction sleeve 24, wherein the end of the connecting rod is fixedly connected to the float, and the suction sleeve is sleeved on the connecting rod;

[0041] like Figure 3-6 As shown, the switch control mechanism includes a main mounting body 31, a tension spring 35 and a permanent magnet fixing bracket 33; wherein the main mounting body is used to mount the relevant components of the switch control mechanism and is connected with other components in the overall device, and a mounting through hole 311 is provided on the main mounting body, and a permanent magnet fixing bracket mounting structure and a switch mounting structure are provided on the main mounting body around the mounting through hole, which are used to mount the permanent magnet fixing bracket and the switch respectively;

[0042] One end of the permanent magnet mounting bracket is movably mounted on the main mounting body. In the specific scheme, the two are rotatably connected through a through hole and a pin 37 provided on the main mounting body. A permanent magnet 32 ​​is installed on the other end of the permanent magnet mounting bracket. At the same time, a trigger member 36 is provided on the permanent magnet bracket, and the permanent magnet faces the axial direction of the mounting through hole, and the trigger member faces the switch mounting structure. When the permanent magnet fixing bracket moves relative to the main mounting body, the permanent magnet moves away from or close to the axial direction of the mounting through hole, and the trigger member moves close to or away from the switch mounting structure.

[0043] One end of the tension spring is connected to the permanent magnet fixing bracket, and the other end is connected to an end of the main mounting body, which end is opposite to the end where the permanent magnet fixing bracket mounting structure is located; the tension spring makes the permanent magnet in a state away from the axial direction of the working through hole and the trigger member in a state away from the switch mounting structure;

[0044] A linear channel is provided in the magnetic isolation sleeve 4;

[0045] The magnetic isolation sleeve is fixedly connected to the mounting interface along the axial direction; the float is located in the float cavity, and the connecting rod extends out of the float cavity through the mounting interface and is located in the channel in the magnetic isolation sleeve, and the attraction sleeve is located on the connecting rod outside the float cavity and is located in the channel in the magnetic isolation sleeve; the switch control mechanism is sleeved on the magnetic isolation sleeve through the mounting through hole, and the connecting rod, the mounting through hole and the channel in the magnetic isolation sleeve are coaxial;

[0046] During specific use, a micro switch 34 is installed at the switch mounting structure. When the medium has not entered the float chamber, the attraction sleeve is axially away from the switch control mechanism; when the liquid level of the monitored medium rises, the float moves toward the top under the action of the buoyancy of the medium, driving the connecting rod to move upward along the channel. When the liquid level reaches the dangerous level, the attraction sleeve reaches the permanent magnet, and the attraction sleeve and the permanent magnet generate magnetic force. Under the action of the magnetic force, the tension spring is compressed, and the permanent magnet fixing bracket drives the trigger member to approach the micro switch at the switch mounting structure to alarm; when the liquid level drops, under the action of the gravity of the sensor unit and the spring elastic force, the permanent magnet moves away from the magnetic isolation sleeve, the trigger member contacts the switch, and the alarm is released.

[0047] The specific working principle of the float liquid level switch of the present invention is as follows: when the liquid level of the medium in the float chamber 1 rises, the float 21 in the sensor unit 2 rises under the action of buoyancy, and the attraction sleeve 24 fixedly connected to the float enters the magnetic field area of ​​the permanent magnet 31 in the switch mechanism 3 and is magnetized. Under the attraction of the attraction sleeve 24, the permanent magnet 31 overcomes the pulling force of the tension spring 35, the permanent magnet fixing bracket rotates, and the permanent magnet is adsorbed on the magnetic isolation sleeve 4 by the attraction sleeve 24; at the same time, the trigger member 36 connected to the permanent magnet fixing bracket disengages the micro switch 34, and the micro switch 34 generates an alarm;

[0048] The liquid level in the float chamber 1 drops, the gravity of the sensor unit 2 is greater than the magnetic force between the attraction sleeve 24 and the permanent magnet 311, the sensor unit drops, the attraction sleeve 24 leaves the magnetic field area of ​​the permanent magnet 31, the permanent magnet 31 is reset under the tension of the tension spring 35, and contacts the trigger bracket 36 fixed with the permanent magnet 311 to trigger the switch, and the micro switch alarm is released.

[0049] It is also necessary to explain that the buoyancy of the float in the sensor unit is greater than the total gravity of the sensor unit. The float 21 can be hollow, solid or semi-hollow with a suitable material. Figure 1The structure shown is hollow. The density of the float is calculated according to the density of the monitored medium. For example, the float material is SS316, and the density range of the monitored medium is 0.55-1g / cm3. The liquid level in the float cavity rises, and the sensor unit rises. When the monitored medium rises to a dangerous level, the magnetic force of the suction sleeve and the permanent magnet overcomes the spring force and the spring is compressed, and the trigger element triggers the micro switch to alarm.

[0050] The liquid level of the monitored medium drops, and the sensor unit drops. When the sensor unit initially drops, the gravity of the sensor unit is greater than 2 times the magnetic force between the attraction sleeve and the permanent magnet, and the sensor unit overcomes the magnetic force and drops. The liquid level of the detected medium continues to drop, and under the action of the gravity of the sensor unit and the spring force, the trigger moves away from the micro switch, and the alarm is released.

[0051] Among them, the role of the magnetic isolation sleeve is to provide axial constraint for the sensor unit to prevent the sensor unit from offset when moving in the axial direction, and on the other hand, to provide a magnetic boundary for the permanent magnet and the attraction sleeve, so that the permanent magnet and the attraction sleeve will only generate magnetic force when the dangerous liquid level is set; in some schemes, the magnetic isolation sleeve also plays an explosion-proof role. For example, according to the requirements of GB3836.2 standard, the material of the magnetic isolation sleeve is austenitic stainless steel SS316 and the wall thickness is 2mm. At this thickness, in order to meet the force relationship requirements between the various components during the working process, the material of the attraction sleeve can be selected from soft magnetic alloys, such as electromagnetic pure iron DT4, DT4E, etc. The coercive force is 39~43A / m, the axial length of the attraction sleeve is 80mm, and the magnetic field strength of the permanent magnet is 2000 Gauss.

[0052] In order to realize multi-position alarm, the switch of the present invention may be equipped with multiple switch control mechanisms along the axial direction, such as Figure 2 As shown, it is a low-level and high-level dual-level alarm, and the axial direction of the suction sleeve must be in the magnetic field area of ​​the permanent magnets of the low-level switch mechanism and the high-level switch mechanism at the same time. When the liquid level in the float chamber rises, the low-level liquid level switch alarms and maintains it. When the liquid level continues to rise, the high-level switch alarms; when the liquid level in the float chamber drops, the high-level switch alarm is released, and when the liquid level continues to drop, the low-level switch alarm is released.

[0053] In order to meet the monitoring of dangerous liquid levels at different heights, in some solutions, the axial installation position of the suction sleeve on the connecting rod is adjustable to meet the needs of different liquid level warnings. In a more specific solution, the connecting rod is a threaded rod, and the suction sleeve and the connecting rod are connected by threads. For example, the axial distance between the top of the suction sleeve and the top of the long screw is between 26.5 and 59.5 mm. If the distance is less than 26.5 mm, the low-level switch is always in an alarm state. If it is greater than 59.5 mm, the high-level switch cannot realize the alarm function.

[0054] In some specific solutions, the connecting rod is welded to the float through a welding joint 23. Specifically, the float 21 and the weld are required to be leak-free. A cylindrical hole is provided on the float welding joint 23, and the connecting rod 22 cooperates with the cylindrical hole and is fixed by welding.

[0055] The shape of the main mounting body can be designed according to the processing, assembly requirements and working requirements. In the preferred scheme, the main mounting body is Z-shaped, and the mounting through hole is arranged on the lower plane body of the Z-shaped main mounting body. The upper plane body 312 of the Z-shaped main mounting body is used to limit the permanent magnet mounting bracket when it moves axially away from the mounting through hole; in a more preferred scheme, considering the processing and assembly requirements, the Z-shaped main mounting body is assembled with two Z-shaped main mounting sub-bodies (31-1, 31-2), and more specifically, the two Z-shaped main mounting sub-bodies are fixed on the magnetic isolation sleeve in a clamping manner by screws.

[0056] In a specific solution, the shape of the float chamber can be designed to a suitable shape according to the working environment, such as Figure 1 and 2 In the example given, the float cavity is elliptical, and the major axis of the ellipse is the axial direction. In a further solution, the elliptical float cavity is connected by welding the middle cylindrical shell 11 and the two end caps (12, 13). To ensure that the float cavity and the magnetic isolation sleeve are installed reliably, the magnetic isolation sleeve includes an axially connected magnetic isolation sleeve 41 and a threaded connection pipe 42. A threaded interface is provided at the top installation interface of the float cavity, and the magnetic isolation sleeve is connected to the threaded interface through the threaded connection pipe 42.

[0057] In a specific embodiment, the permanent magnet 32 ​​and the switch trigger 36 are fixed to the permanent magnet fixing bracket 33 by screws, and a trigger rod 361 is fixed to the switch trigger by screws for triggering the switch. Further, a hook 331 is fixed to the permanent magnet mounting bracket by screws, and one end of the tension spring is fixed in the hook.

[0058] In some specific solutions, the main mounting body is provided with a terminal mounting structure, and a terminal fixing frame 39 is provided or installed at the terminal mounting structure for installing the terminal 310. For example, the terminal 310 is provided with 6 terminals, of which 3 terminals are connected to the micro switch and 3 terminals are connected to the user-side control device. In a more specific solution, a hook is provided on the terminal fixing frame, and the other end of the tension spring 35 is connected to the hook.

[0059] In the specific scheme, a switch bracket 38 is fixed to the switch mounting structure by screws, and a micro switch 34 is fixed to the switch bracket 38 by screws, such as a micro switch of model Omron z-15WG55. The switch is a dry contact switch, single-pole double-throw, with a common terminal c. When not triggered, terminals a and c are connected, and terminals b and c are disconnected. When triggered, terminals a and c are disconnected, and terminals b and c are connected. In the case of the present invention, terminals a and c are connected, and terminals b and c are disconnected in the initial position.

[0060] In some schemes, the float liquid level switch of the present invention further includes a shell 5, which is located above the float cavity, and the magnetic isolation sleeve extends into the shell, while the switch control mechanism is located in the shell, and the bottom of the shell is connected to the magnetic isolation sleeve or the float cavity; the shell is provided with a wiring inlet and outlet 6. In a further scheme, the shell is composed of an upper shell 51 and a lower shell 52 threadedly connected to form a shell, and the wiring inlet and outlet are arranged on the lower shell. To meet the wiring requirements in different directions, in addition, the above two wiring ports are both threaded, and the wiring terminal is sealed with an explosion-proof stuffing sealing hood 6, the above-mentioned explosion-proof stuffing sealing hood 6 is threadedly connected to the inlet, and the non-wiring terminal is blocked with an explosion-proof plug 7, the above-mentioned explosion-proof plug is threadedly connected to the non-wiring terminal, and a grounding device is also provided at the lower part of the shell. In the specific scheme, the magnetic isolation sleeve 4, the electrical housing 5, the explosion-proof and explosion-proof stuffing sealing box 6, the explosion-proof plug 7 and the grounding device together constitute an explosion-proof cavity, which provides space for the installation of low-level and high-level switch structures and meets the explosion-proof grade requirements of the float liquid level switch, such as the explosion-proof grade ExdⅡBT6, wherein the magnetic isolation sleeve assembly 4 is fixed to the lower shell 52 by threaded connection.

Claims

1. A float liquid level switch, characterized in that: It includes a float chamber, a sensor unit, a switch control mechanism and a magnetic isolation sleeve; The float chamber is a hollow structure, the float chamber is provided with a medium inlet at the axial bottom, a mounting interface at the top, and a medium overflow port on the side wall; The sensing unit comprises a floating ball, a connecting rod and a suction sleeve, wherein the suction sleeve is made of a magnetic conductive material, the connecting rod is fixedly connected to the floating ball, and the suction sleeve is sleeved on the connecting rod; The switch control mechanism includes a main mounting body, a tension spring and a permanent magnet fixing bracket; The main mounting body is provided with a mounting through hole, and a switch mounting structure and a permanent magnet fixing bracket mounting structure are provided on the main mounting body around the mounting through hole; One end of the permanent magnet fixing bracket is movably mounted on the permanent magnet fixing bracket mounting structure, and the other end is mounted with a permanent magnet. At the same time, a triggering member is provided on the permanent magnet bracket, and the permanent magnet faces the axial direction of the mounting through hole, and the triggering member faces the switch mounting structure. When the permanent magnet fixing bracket moves relative to the main mounting body, the permanent magnet moves away from or close to the axial direction of the mounting through hole, and the triggering member moves close to or away from the switch mounting structure. One end of the tension spring is connected to the permanent magnet fixing bracket, and the other end is connected to an end of the main mounting body, which end is opposite to the end where the permanent magnet fixing bracket mounting structure is located; the tension spring makes the permanent magnet in a state away from the axial direction of the working through hole and the trigger member in a state close to the switch mounting structure; A linear channel is provided in the magnetic isolation sleeve; The magnetic isolation sleeve is fixedly connected to the mounting interface along the axial direction; the float is located in the float cavity, and the connecting rod extends out of the float cavity through the mounting interface and is located in the channel in the magnetic isolation sleeve, and the attraction sleeve is located on the connecting rod outside the float cavity and is located in the channel in the magnetic isolation sleeve; the switch control mechanism is sleeved on the magnetic isolation sleeve through the mounting through hole, and the connecting rod, the mounting through hole and the channel in the magnetic isolation sleeve are coaxial; When the sensing unit is not acted upon by buoyancy, the attraction sleeve moves axially upward away from the switch control mechanism; when the liquid level in the float chamber rises, the float moves toward the top under the action of the buoyancy of the medium, driving the connecting rod to move upward along the channel, and when it rises to a dangerous liquid level, the tension spring is compressed under the action of the attraction sleeve and the magnetic force of the permanent magnet, and the permanent magnet fixing bracket drives the trigger member away from the switch mounting structure.

2. The float level switch according to claim 1, characterized in that: It comprises two switch control mechanisms, which are sleeved on the magnetic isolation sleeve in sequence along the axial direction.

3. The float liquid level switch according to claim 1, characterized in that: The wall thickness of the magnetic isolation sleeve is 2 mm, the coercive force of the attraction sleeve is 39-43 A / m, and the magnetic field strength of the permanent magnet is 2000 Gauss.

4. The float liquid level switch according to claim 1, characterized in that: The connecting rod is a threaded rod, and the axial installation position of the attraction sleeve on the connecting rod is adjustable.

5. The float liquid level switch according to claim 1, characterized in that: The connecting rod is a threaded rod, and the suction sleeve is threadedly connected to the connecting rod.

6. The float level switch according to claim 1, characterized in that: A switch mounting structure, a permanent magnet fixing bracket mounting structure and a wiring terminal mounting structure are arranged on the main mounting body around the mounting through hole, and a wiring terminal fixing frame is arranged at the wiring terminal mounting structure.

7. The float level switch according to claim 6, characterized in that: The wiring terminal fixing frame is provided with wiring terminals.

8. The float liquid level switch according to claim 6, characterized in that: The other end of the tension spring is connected to the wiring terminal fixing frame.

9. The float liquid level switch according to claim 1, characterized in that: It also includes a micro switch, which is installed at the switch installation structure, and when the permanent magnet moves toward the magnetic isolation sleeve, the trigger member contacts and presses a switch key on the micro switch.

10. The float liquid level switch according to claim 1, characterized in that: A threaded interface is provided at the installation interface of the float chamber, and the magnetic isolation sleeve is connected to the threaded interface through a threaded connection joint.

11. The float liquid level switch according to claim 1, characterized in that: The float cavity is elliptical, and the major axis of the ellipse is the axial direction.

12. The float liquid level switch according to claim 1, characterized in that: The main mounting body is Z-shaped, the working through hole is arranged on the transverse section below the Z-shaped main mounting body, the permanent magnet fixing bracket is movably mounted on the vertical section of the Z-shaped main mounting body, and the transverse section above the Z-shaped main mounting body is used to limit the rotation angle of the permanent magnet fixing bracket when it moves axially away from the working through hole.

13. The float liquid level switch according to claim 1, characterized in that: It also includes a shell, which is located above the float cavity, and the magnetic isolation sleeve extends into the shell. At the same time, the switch control mechanism is located in the shell, and the bottom of the shell is connected to the magnetic isolation sleeve or the float cavity; the shell is provided with a wiring inlet and outlet.

14. The float liquid level switch according to claim 13, characterized in that: The housing comprises an upper housing and a lower housing, the upper housing and the lower housing are threadedly connected to form a housing, and the wiring inlet and outlet are arranged on the lower housing.

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