A reed switch type liquid level sensor
By adopting a cross-layout reed tube design in the reed tube level sensor, the measurement dead zone and sudden change problems of traditional liquid level sensors are solved, and the liquid level measurement with no dead zone and consistent accuracy of the entire range is achieved.
Patent Information
- Application Number
- CN202421611615.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-09
- Publication Date
- 2025-04-04
- Estimated Expiration
- 2034-07-09
AI Technical Summary
Traditional reed tube level sensors have problems with measurement dead zones and mutations, especially when the float is close to both ends of the reed tube, the reed tube may not be absorbed, resulting in inaccurate measurements.
The reed tube design adopts a cross-layout reed tube, and the annular magnetic ring float moves up and down with the liquid level, greatly reducing the measurement dead zone and sudden changes caused by the reed tube's non-absorbing and layout gap.
It realizes dead-range liquid level measurement, with consistent accuracy across the entire scale, no temperature coefficient or nonlinearity, and has higher measurement accuracy than capacitive or pressure liquid level sensors.
Smart Images
Figure CN222719018U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of liquid level sensors, in particular to a reed switch type liquid level sensor. Background Art
[0002] A reed switch is a sensitive element consisting of a specially packaged reed and a magnet. It usually contains two electric shock reeds. The reeds are in an open state when not affected by a magnetic field. When an external magnetic field approaches, the reeds will be attracted and closed, realizing a switching effect.
[0003] The reed switch sensor, also known as the reed switch liquid level gauge, uses the reed switch's sensitivity to magnetic fields to detect liquid levels. In the liquid level gauge, the reed switch is usually installed on a circuit board (PCB) inside the casing of the liquid level gauge. The float with an annular magnetic ring inside moves up and down with the change of liquid level. When the magnet rises or falls to the vicinity of the reed switch with the liquid level, the reed inside the reed switch is closed by the magnetic field, thereby triggering a change in the circuit. By detecting this circuit change, the liquid level can be accurately judged.
[0004] At present, the reed switches in traditional reed switch sensors all adopt a vertical cascade design, but there will be a gap between the two reed switches. In addition, when the float is close to the two ends of the reed switch, the reed switch may not be attracted, resulting in measurement dead zones and mutations. Utility Model Content
[0005] The purpose of the utility model is to provide a reed switch type liquid level sensor to solve the problems raised in the above background technology.
[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a reed switch type liquid level sensor, comprising a liquid level meter housing and an annular magnetic ring float slidably sleeved on the outer surface of the liquid level meter housing, an installation groove is opened inside the liquid level meter housing, a PCB circuit board is fixedly installed on the rear inner wall of the installation groove, and a cross-distributed reed switch is installed on the front of the PCB circuit board through an installation component. Through the cross-layout, when the annular magnetic ring float moves up and down with the liquid level, the measurement dead zone and mutation caused by the reed switch not being attracted and the reed switch layout gap inside the traditional reed switch sensor are greatly reduced. In this layout, although there is a possibility that two reed switches are attracted at the same time, if the length of several reed switches is mm, the maximum uncertainty when they are attracted at the same time is mm. The larger the measuring range, the smaller the relative measurement error caused by this uncertainty. Compared with the influence of the measurement dead zone and mutation, this uncertainty can be ignored. The outer surface of the liquid level meter housing is provided with a sliding component for assisting the annular magnetic ring float to slide on its surface.
[0007] Preferably, the mounting assembly includes a connecting rod rotatably sleeved on the surface of the PCB circuit board, and the outer surface of the connecting rod is sleeved with a torsion spring. Adding a torsion spring connection to the reed tube type liquid level sensor of the present application has the following advantages:
[0008] Vibration absorption: Torsion springs can help absorb vibration and impact on the sensor, thereby reducing damage to the sensor and PCB circuit board and improving the reliability of the equipment;
[0009] Thermal expansion compensation: In an environment with large temperature changes, the thermal expansion coefficients of the materials of the PCB circuit board and the sensor are different, which may cause stress in the connection part. The torsion spring can partially compensate for the displacement caused by thermal expansion, reduce the force on the connection part, and help maintain the stability of the connection; one end of the torsion spring is connected to the surface of the PCB circuit board.
[0010] Preferably, the other end of the torsion spring is fixedly connected to the outer surface of the connecting rod, and the front side of the connecting rod is electrically connected to the back side of the reed switch.
[0011] Preferably, the sliding assembly comprises auxiliary sliding grooves which are symmetrically distributed on the surface of the level meter housing, and the cross section of the auxiliary sliding grooves is in an arc shape.
[0012] Preferably, the inner surface of the annular magnetic ring float is rotatably sleeved with auxiliary sliding balls distributed in a linear array, the outer surface of the auxiliary sliding balls is slidably sleeved with the inner wall of the auxiliary sliding groove, and the auxiliary sliding balls are made of any one of polyethylene, polypropylene, polyvinyl chloride and polycarbonate.
[0013] Compared with the prior art, the beneficial effects of the utility model are: the reed switch liquid level sensor, compared with the capacitive or pressure liquid level sensor, can achieve dead-zone liquid level measurement, consistent accuracy over the entire range, and no temperature coefficient and nonlinearity, which are the shortcomings of capacitive or pressure liquid level sensors. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is a schematic diagram of the structure of the utility model;
[0015] Figure 2 A three-dimensional diagram of the annular magnetic ring float structure of a reed switch type liquid level sensor proposed by the utility model;
[0016] Figure 3 A reed switch type liquid level sensor proposed by the utility model Figure 2 A magnified view of the structure at center;
[0017] Figure 4 A three-dimensional diagram of the auxiliary sliding ball structure of a reed switch type liquid level sensor proposed by the utility model;
[0018] Figure 5 A three-dimensional diagram of the connecting rod structure of a reed switch type liquid level sensor proposed by the utility model;
[0019] Figure 6 The present invention provides a schematic diagram of the signal conversion principle of a reed switch type liquid level sensor.
[0020] In the figure: 1. Liquid level meter housing; 2. Ring magnetic float; 3. Mounting groove; 4. PCB circuit board; 5. Reed switch; 6. Connecting rod; 61. Torsion spring; 7. Auxiliary slide groove; 71. Auxiliary slide ball. DETAILED DESCRIPTION
[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0022] See also Figure 1-Figure 6 The utility model provides a technical solution: a reed switch type liquid level sensor, comprising a liquid level meter housing 1 and an annular magnetic ring float 2 slidably sleeved on the outer surface of the liquid level meter housing 1, an installation groove 3 is opened inside the liquid level meter housing 1, a PCB circuit board 4 is fixedly installed on the rear inner wall of the installation groove 3, and a cross-distributed reed switch 5 is installed on the front of the PCB circuit board 4 through an installation component. Through the cross-layout, when the annular magnetic ring float 2 moves up and down with the liquid level, the measurement dead zone and mutation caused by the reed switch 5 not being attracted and the layout gap of the reed switch 5 inside the traditional reed switch sensor are greatly reduced. In this layout, although there is a possibility that two reed switches 5 are attracted at the same time, if the length of several reed switches 5 is 5mm, the maximum uncertainty when they are attracted at the same time is 5mm. The larger the measuring range, the smaller the relative measurement error caused by this uncertainty. Compared with the influence of the measurement dead zone and mutation, this uncertainty can be ignored. The outer surface of the liquid level meter housing 1 is provided with a sliding component for assisting the annular magnetic ring float 2 to slide on its surface.
[0023] Furthermore, the mounting assembly includes a connecting rod 6 that is rotatably sleeved on the surface of the PCB circuit board 4, and a torsion spring 61 is sleeved on the outer surface of the connecting rod 6. Adding a torsion spring 61 to the reed tube type liquid level sensor of the present application has the following advantages:
[0024] Vibration absorption: The torsion spring 61 can help absorb the vibration and impact of the sensor, thereby reducing damage to the sensor and the PCB circuit board 4 and improving the reliability of the device;
[0025] Thermal expansion compensation: In an environment with large temperature changes, the thermal expansion coefficients of the materials of the PCB circuit board 4 and the sensor are different, which may cause stress in the connection part. The torsion spring 61 can partially compensate for the displacement caused by thermal expansion, reduce the force on the connection part, and help maintain the stability of the connection; one end of the torsion spring 61 is connected to the surface of the PCB circuit board 4, and the other end of the torsion spring 61 is fixedly connected to the outer surface of the connecting rod 6, and the front side of the connecting rod 6 is electrically connected to the back side of the reed switch 5.
[0026] Furthermore, the sliding assembly includes auxiliary slide grooves 7 symmetrically distributed on the surface of the liquid level meter housing 1, the cross-section of the auxiliary slide grooves 7 is arc-shaped, the inner surface of the annular magnetic ring float 2 is rotatably sleeved with auxiliary slide balls 71 distributed in a linear array, the outer surface of the auxiliary slide ball 71 is slidably sleeved with the inner wall of the auxiliary slide groove 7, and the auxiliary slide ball 71 is made of any one of polyethylene, polypropylene, polyvinyl chloride and polycarbonate.
[0027] Working principle: Through the cross layout, when the annular magnetic ring float 2 moves up and down with the liquid level, the measurement dead zone and mutation caused by the non-attraction of the reed switch 5 and the layout gap of the reed switch 5 inside the traditional reed switch sensor are greatly reduced. In this layout, although there is a possibility that two reed switches 5 are attracted at the same time, if the length of several reed switches 5 is 5mm, the maximum uncertainty when they are attracted at the same time is 5mm. The larger the measuring range, the smaller the relative measurement error caused by this uncertainty. Compared with the influence of measurement dead zone and mutation, this uncertainty can be ignored.
[0028] The signal conversion process of the reed switch type liquid level sensor of the present application is as follows: when the reed switch 5 is closed, the circuit is turned on and a corresponding electrical signal is generated;
[0029] When the reed switch 5 is disconnected, the circuit is disconnected and the electrical signals disappear. These electrical signals are received and processed by the control system and further converted into readable liquid level signals. Specifically:
[0030] like Figure 6 As shown, when the liquid level is at P1, the P1 reed switch 5 is turned on due to the action of the annular magnetic ring float 2, and the resistance between RIN1 and RIN2 is 0 ohms.
[0031] When the liquid level is at P2, due to the action of the annular magnetic float 2, the P2 reed switch 5 is turned on, and P1 is disconnected, then the resistance between RIN1 and RIN2 is 2K ohms.
[0032] Similarly, by measuring the resistance between RIN1 and RIN2, the liquid level height can be calculated.
[0033] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A reed switch type liquid level sensor, comprising a liquid level meter housing (1) and an annular magnetic ring float (2) slidably sleeved on the outer surface of the liquid level meter housing (1), characterized in that: The liquid level meter housing (1) is provided with a mounting groove (3) inside, a PCB circuit board (4) is fixedly mounted on the rear inner wall of the mounting groove (3), a cross-distributed reed switch (5) is mounted on the front of the PCB circuit board (4) via a mounting assembly, and a sliding assembly for assisting the annular magnetic ring float (2) to slide on its surface is provided on the outer surface of the liquid level meter housing (1).
2. A reed switch type liquid level sensor according to claim 1, characterized in that: The mounting assembly comprises a connecting rod (6) rotatably sleeved on the surface of a PCB circuit board (4); a torsion spring (61) is sleeved on the outer surface of the connecting rod (6); one end of the torsion spring (61) is connected to the surface of the PCB circuit board (4).
3. A reed switch type liquid level sensor according to claim 2, characterized in that: The other end of the torsion spring (61) is fixedly connected to the outer surface of the connecting rod (6), and the front side of the connecting rod (6) is electrically connected to the back side of the reed switch (5).
4. A reed switch type liquid level sensor according to claim 1, characterized in that: The sliding assembly comprises auxiliary sliding grooves (7) which are symmetrically distributed on the surface of the liquid level meter housing (1); the cross section of the auxiliary sliding grooves (7) is in the shape of an arc.
5. A reed switch type liquid level sensor according to claim 4, characterized in that: The inner surface of the annular magnetic ring float (2) is rotatably sleeved with auxiliary sliding balls (71) distributed in a linear array, and the outer surface of the auxiliary sliding balls (71) is slidably sleeved with the inner wall of the auxiliary sliding groove (7).