A liquid medium pressure sensor

Abstract

The application discloses a liquid medium pressure sensor, comprising: a medium channel for transmitting a liquid medium to be measured; a pressure measuring device in communication with the medium channel for measuring the pressure of the liquid medium to be measured; a porous structure between the medium channel and the pressure measuring device, the porous structure having a large number of continuous pores inside, the continuous pores being capable of communicating the medium channel and the pressure measuring device, the aperture of the continuous pores being less than 1 mm, and the continuous pores being capable of providing crystal nuclei to make the liquid medium to be measured inside the continuous pores freeze first in a low-temperature environment. The liquid medium pressure sensor of the application can realize the anti-freezing protection of the liquid medium sensor while ensuring the detection function. Compared with the prior art, the application has a simple structure, does not need to set a bubble or change the mounting mode of the pressure measuring device, and thus can reduce the production difficulty and cost.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sensors, and particularly relates to a liquid medium pressure sensor. BACKGROUND

[0002] The liquid pressure sensor comprises a pressure measuring device and a medium channel in communication with the pressure measuring device. In specific use, the medium channel is in communication with a device to be measured, and can lead the liquid medium to be measured to the pressure measuring device to realize pressure detection. However, in a low-temperature environment (the temperature reaches the freezing point), the liquid medium to be measured in the medium channel will freeze. After the liquid medium to be measured freezes, the volume increases, and the pressure measuring device is pressed to be damaged. To solve the above problem, certain protective measures are needed, for example, a bubble capable of being compressed and shrunk can be arranged in the medium channel, or the installation mode of the pressure measuring device can be changed, so that the pressure measuring device can move relative to the medium channel when being pressed by the frozen medium. However, the existing protective measures will make the structure of the pressure sensor more complex, and the production difficulty and cost are correspondingly increased. SUMMARY

[0003] The application aims to at least solve one of the technical problems in the prior art, and provides a liquid medium pressure sensor.

[0004] The application provides a liquid medium pressure sensor, comprising:

[0005] a medium channel for transmitting a liquid medium to be measured;

[0006] a pressure measuring device in communication with the medium channel, for measuring the pressure of the liquid medium to be measured;

[0007] a porous structure between the medium channel and the pressure measuring device, the porous structure has a large number of continuous pores inside, the continuous pores can communicate the medium channel and the pressure measuring device, and the pore diameter of the continuous pores is less than 1 mm, and in a low-temperature environment, the continuous pores can provide crystal nuclei to make the liquid medium to be measured located in the continuous pores freeze first.

[0008] In some embodiments, the pore diameter of the continuous pores is less than 0.3 mm.

[0009] In some embodiments, the surface of the continuous pores is a hydrophilic surface.

[0010] In some embodiments, the porous structure is made of metal.

[0011] In some embodiments, the porous structure is formed by interlaced stacking of multiple layers of metal mesh.

[0012] In some embodiments, the continuous hole has multiple turning points inside.

[0013] In some embodiments, the liquid medium pressure sensor further comprises:

[0014] A damping cavity is located between the medium channel and the porous structure and is capable of connecting the medium channel and the porous structure, and the pore size of the damping cavity is larger than the pore size of the medium channel.

[0015] In some embodiments, the pore size of the damping cavity gradually increases in the direction close to the porous structure.

[0016] In some embodiments, the damping cavity is a conical cavity.

[0017] In some embodiments, a damping structure is arranged in the damping cavity, and the damping structure is configured to buffer the pressure of the liquid medium to be measured.

[0018] The above technical solutions of the present application have the following beneficial technical effects:

[0019] The liquid medium pressure sensor of the present application has a porous structure between the pressure measuring device and the medium channel, and the continuous hole inside the porous structure can allow the liquid medium to be measured to pass through for pressure detection. In addition, the small pore size of the continuous hole can provide nucleation sites for the liquid medium to be measured, so that the liquid medium to be measured can freeze at the position of the porous structure first, thereby blocking the influence of the expansion of the frozen medium outside the porous structure on the pressure measuring device. Compared with the prior art, the liquid medium pressure sensor of the present application has a simple structure, and does not need to set a bubble or change the installation method of the pressure measuring device, thereby reducing the production difficulty and cost. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic diagram of a liquid medium pressure sensor in an exemplary embodiment of the present application;

[0021] Figure 2 is a schematic diagram of verification experiment 1;

[0022] Figure 3 is a schematic diagram of verification experiment 2;

[0023] Figure 4 is a curve of the influence of the porous structure with different hole diameters on the depth of the upper surface of the piston A12;

[0024] In the figure, 1 is a pressure measuring device; 2 is a medium channel; 3 is a porous structure; 31 is a continuous hole; 4 is a damping cavity; 5 is an outer shell; 11 is a straight cylinder open container; 12 is a piston A; 13 is a piston B; 14 is a damping spring; and 15 is a porous material. DETAILED DESCRIPTION

[0025] In the prior art, the pressure measuring device of the liquid pressure sensor itself has certain pressure resistance, so that it can adapt to the pressure of the liquid medium to be measured. However, in a low-temperature environment (the temperature reaches the freezing point), the liquid medium to be measured in the medium channel will freeze. After the liquid medium to be measured freezes, the volume increases and the pressure increases, exceeding the range that the pressure measuring device can withstand, thereby causing damage to the pressure measuring device.

[0026] In order to solve the above technical problems, the present application is proposed to reduce the risk of freezing damage of the liquid pressure sensor in a low-temperature environment.

[0027] The embodiments of the present application will be further described in detail below in combination with the drawings and examples. The detailed description of the following examples and the drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described examples.

[0028] Figure 1 is a structural schematic diagram of a liquid medium pressure sensor in an exemplary embodiment of the present application.

[0029] As shown in Figure 1 , the liquid medium pressure sensor includes a pressure measuring device 1 and a medium channel 2, and the pressure measuring device 1 communicates with the medium channel 2. The medium channel 2 is used to transmit the liquid medium to be measured to the pressure measuring device 1. The pressure measuring device 1 is used to measure the pressure of the liquid medium to be measured.

[0030] Further, the above-mentioned liquid medium pressure sensor further includes a porous structure 3, the porous structure 3 is located between the medium channel 2 and the pressure measuring device 1, the porous structure 3 has a large number of continuous pores inside, the continuous pores can communicate the medium channel 2 and the pressure measuring device 1, and the aperture of the continuous pores is less than 1mm, in a low-temperature environment, the continuous pores can provide crystal nuclei to make the liquid medium to be measured located in the continuous pores freeze first.

[0031] It can be understood that the first end of the continuous pores communicates with the medium channel 2, and the second end of the continuous pores communicates with the pressure measuring device 1. The continuous pores can allow the liquid medium to be measured to pass through for pressure detection.

[0032] It can also be understood that the continuous pores can form a nucleation site to make the liquid medium located therein freeze first, and then when the liquid medium located in the medium channel 2 freezes, the expansion pressure generated by the freezing of the liquid medium can be blocked by the porous structure 3 and the frozen medium located therein, so that the risk of damage to the pressure measuring device 1 due to the freezing of the liquid medium in a low-temperature environment can be reduced. Compared with the prior art, the liquid medium pressure sensor of the embodiment has a simple structure, does not need to be provided with a bubble, or the mounting mode of the pressure measuring device 1 needs to be changed, so that the production difficulty and cost can be reduced.

[0033] In order to verify the feasibility of the above scheme, the following specific analysis is carried out through experiments in combination with Figure 2 and Figure 3 .

[0034] Experimental apparatus:

[0035] Straight open container 11, piston A 12, piston B 13, damping spring 14, porous material 15 (with continuous pores with a diameter of 0.2 mm), and standard saline solution with a concentration of 0.9%.

[0036] Experimental conditions:

[0037] The piston A 12 and the piston B 13 can realize complete sealing of the solution and free up-and-down movement in the container.

[0038] Experiment 1:

[0039] As shown in Figure 2 , the distance from the upper surface of the piston A 12 to the top end of the straight open container 11 is H before the solution freezes, and at this time H is greater than 0. When the temperature decreases to the freezing point, the solution in the straight open container 11 begins to freeze, at this time the piston A 12 is pushed upward by the volume expansion of the solution and the ice mixture during the freezing process of the solution, and the piston B 13 remains unchanged because the pushing force of the damping spring 14 is greater than the pushing force of the ice. When the freezing process is completely completed, the piston A 12 is just flush with the top end of the container, and at this time H = 0.

[0040] Experiment 2:

[0041] As shown in Figure 3 , on the basis of experiment 1, the porous material 15 is installed close to the bottom of the piston A 12, and the porous material 15 is fixed relative to the straight open container 11. When the freezing process is completely completed, the piston B 13 moves downward, only a small amount of solution is frozen between the piston A 12 and the porous material 15, and the upward movement distance of the piston A 12 is greatly reduced.

[0042] According to the above experiment, it is not difficult for those skilled in the art to conceive that the solution can be frozen in advance in the porous material 15, and only when the solution is frozen in advance in the porous material 15, the distance of the downward movement of the piston B13 and the upward movement of the piston A12 can be greatly reduced. Similarly, by arranging the porous structure 3 in the medium channel 2 and the pressure measuring device 1 of the liquid pressure sensor, the pressure of the frozen liquid medium on the pressure measuring device 1 can be reduced, thereby reducing the risk of damage to the pressure measuring device 1 due to the freezing of the liquid medium to be measured in a low-temperature environment.

[0043] Further, in order to verify the influence of the pore size of the continuous pores on the experimental results, experiments are sequentially performed using porous materials 15 with different pore diameters (the pore diameters of different porous materials 15 are 0.10 mm, 0.20 mm, 0.30 mm, 0.40 mm, …, 1.5 mm, respectively), the distance from the upper surface of the piston A12 to the top end of the straight open container 11 in each experiment is obtained, and the obtained data is plotted into a curve diagram as shown in FIG. 4. Figure 4 As can be seen, the smaller the pore diameter of the porous material 15, the greater the distance from the upper surface of the piston A12 to the top end of the straight open container 11, that is, the smaller the pressure on the piston A12. Similarly, in the above liquid pressure sensor, the smaller the pore diameter of the porous structure 3, the smaller the influence of the freezing of the liquid medium to be measured on the pressure measuring device 1.

[0044] In some optional embodiments, the pore size of the continuous pores is less than 0.3 mm. It can be understood that the inside of the porous structure 3 has a large number of continuous pores, and the pore sizes of different continuous pores can be different, but all should satisfy the pore size less than 0.3 mm.

[0045] In some optional embodiments, the surface of the continuous pores is a hydrophilic surface. It can be understood that a hydrophobic surface will prolong the freezing time of the liquid, and compared with a hydrophobic surface, the liquid is more likely to freeze on a hydrophilic surface and freeze faster, which is conducive to the realization of the function of freezing the liquid medium to be measured in the continuous pores 3 in advance.

[0046] In some optional embodiments, the porous structure 3 is made of metal. It can be understood that when the ambient temperature suddenly decreases, the temperature of the material that decreases slowly will be higher than the ambient temperature, which is not conducive to the realization of freezing in advance. The metal material has good thermal conductivity, and when the ambient temperature decreases, it can quickly decrease the temperature, so that the liquid medium to be measured can quickly decrease the temperature when contacting the porous structure 3 to freeze. Therefore, the porous structure 3 made of metal can improve the reliability of the pressure sensor.

[0047] In some alternative embodiments, the porous structure 3 can be formed by a plurality of metal mesh layers being stacked in an interleaved manner. It can be appreciated that, when the plurality of metal mesh layers are stacked in an interleaved manner, the mesh holes of adjacent metal mesh layers are arranged in an interleaved manner, so as to form the continuous holes.

[0048] In some alternative embodiments, the continuous holes have a plurality of turning points inside. In specific applications, the hydraulic system of the device to be tested is suddenly started, stopped, speed-changed or reversed, so as to cause a sudden pressure surge (3-4 times of the normal working pressure). The impact on the signal output of the pressure sensor is slight, while the physical damage to the pressure measuring device 1 of the pressure sensor is severe. The turning points inside the continuous holes can have a damping effect on the liquid medium to be tested, so as to reduce the impact pressure of the liquid medium to be tested, thereby avoiding the damage to the pressure measuring device 1 caused by the impact.

[0049] In some alternative embodiments, the liquid medium pressure sensor further comprises a damping cavity 4, which is located between the medium channel 2 and the porous structure 3 and can communicate the medium channel 2 and the porous structure 3, and the pore diameter of the damping cavity 4 is larger than that of the medium channel 2. As shown in the figure, specifically, the first end of the damping cavity 4 communicates with the medium channel 2, and the second end of the damping cavity 4 communicates with the plurality of continuous holes. It can be appreciated that, when the liquid medium to be tested passes through the damping cavity 4 with a larger pore diameter, the damping cavity 4 can buffer the pressure of the liquid medium to be tested. Figure 1

[0050] It should be noted that the liquid medium pressure sensor comprises a shell 5, and the damping cavity 4 and the medium channel 2 can be cavities located in the shell 5. That is, in specific implementation, the shell 5 can be prepared by injection molding or other processes, and the damping cavity 4 and the medium channel 2 can be formed in the shell 5 at the same time as the shell 5 is prepared. Alternatively, the pore diameter of the medium channel 2 is 3 mm, and the pore diameter of the damping cavity 4 is 5 mm.

[0051] In some alternative embodiments, the pore diameter of the damping cavity 4 gradually increases in the direction close to the porous structure 3. It can be appreciated that, in the process that the liquid medium to be tested passes through the damping cavity 4, the impact pressure of the liquid medium to be tested gradually decreases as the pore diameter of the damping cavity 4 gradually increases. Preferably, the damping cavity 4 is a conical cavity.

[0052] ​In some optional embodiments, the damping cavity 4 is provided with a damping structure (not shown in the figure) configured to buffer the pressure of the liquid medium to be measured. Exemplarily, the damping structure can be a partition plate or a protrusion, etc. For example, the inner wall of the damping cavity 4 is provided with a plurality of partition plates, and the plurality of partition plates are staggered to form a zigzag channel. When the liquid medium to be measured passes through the channel, the turning points of the channel can further buffer the pressure of the liquid medium to be measured.

[0053] In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "a plurality of" is more than two; the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer" and the like only indicates or implies the relative position relationship for the purpose of facilitating the description of the present application and simplifying the description, and cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable range of error. "Parallel" is not strictly parallel, but within the allowable range of error.

[0054] In the description of the present application, it should also be noted that, unless otherwise specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0055] The embodiments of the present application are described above in combination with the drawings, but the present application is not limited to the above specific embodiments, and the above specific embodiments are only illustrative, not restrictive. Those skilled in the art can make many forms under the inspiration of the present application without departing from the scope of the present application and the scope of protection of the claims, which all belong to the protection of the present application.

Claims

1. A liquid medium pressure sensor, characterized in that, include: Medium channel, used to transmit the liquid medium to be tested; A pressure measuring device, connected to the medium channel, is used to measure the pressure of the liquid medium to be measured; A porous structure is located between the medium channel and the pressure measuring device. The porous structure is made of metal and has a large number of continuous pores inside. The continuous pores can connect the medium channel and the pressure measuring device. Furthermore, the pore diameter of the continuous pores is less than 1 mm. In a low-temperature environment, the continuous pores can provide crystallization nuclei, causing the liquid medium to be tested located in the continuous pores to freeze first.

2. The liquid medium pressure sensor according to claim 1, characterized in that, The diameter of the continuous hole is less than 0.3 mm.

3. The liquid medium pressure sensor according to claim 1, characterized in that, The surface of the continuous pores is a hydrophilic surface.

4. The liquid medium pressure sensor according to claim 1, characterized in that, The porous structure is formed by stacking multiple layers of metal mesh.

5. The liquid medium pressure sensor according to claim 1, characterized in that, The continuous hole has multiple turning points inside.

6. The liquid medium pressure sensor according to claim 1, characterized in that, The liquid medium pressure sensor also includes: A damping cavity is located between the medium channel and the porous structure and can connect the medium channel and the porous structure. The diameter of the damping cavity is larger than the diameter of the medium channel.

7. The liquid medium pressure sensor according to claim 6, characterized in that, Along the direction close to the porous structure, the aperture of the damping cavity gradually increases.

8. The liquid medium pressure sensor according to claim 7, characterized in that, The damping cavity is a conical cavity.

9. The liquid medium pressure sensor according to claim 6, characterized in that, The damping cavity is equipped with a damping structure, which is configured to buffer the pressure of the liquid medium to be tested.

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