A differential pressure sensor with a PFA pressure guide tube

Abstract

The utility model discloses a PFA pressure guide pipe differential pressure sensor, include: shell, the bottom of shell is provided with the intercommunication, is installed on the intercommunication with the self -locking ball one -way valve, inner shell, end cover, PFA pressure guide pipe, PFA pressure guide pipe sets up on the end cover, and the upper end of PFA pressure guide pipe is provided with sealing assembly, and the lateral wall of PFA pressure guide pipe is provided with first pressure guide hole and second pressure guide hole, air chamber, air chamber includes setting in the upper air chamber and lower air chamber of shell, and the upper end and lower end of PFA pressure guide pipe respectively passes through the lateral wall of inner shell and respectively stretches into the upper and lower air chamber, piston, the bottom of piston is installed with magnet disc, base plate, electric eddy current probe, electric eddy current probe sets up on base plate, buffer assembly, buffer assembly installs in the bottom of end cover, the utility model discloses the PFA pressure guide pipe and piston as the sensitive element, uses electric eddy current type measurement principle, and it is simple in structure, low in cost, and has higher differential pressure measurement accuracy.

Description

Technical Field

[0001] This utility model relates to the field of pressure sensor technology, and in particular to a PFA pressure guide tube differential pressure sensor. Background Technology

[0002] Micro-differential pressure sensors are commonly used in industrial fields. They are generally composed of a sensing element and a signal processing unit. While there are many types and a wide range of applications, the number of sensors specifically designed for micro-differential pressure measurement is limited. Domestically, capacitive and strain gauge sensors are predominantly used, while internationally, piezoresistive and resonant sensors are available. Capacitive and strain gauge pressure sensors are widely used due to their good performance, but they suffer from creep, hysteresis, temperature drift, low repeatability, and complex circuitry, resulting in a measurement accuracy of approximately 2.0%, which is insufficient for high-precision testing requirements such as differential pressure interference and pulse differential pressure. For these types of micro-differential pressure tests, piezoresistive and resonant pressure sensors are typically used, but these sensors are complex in structure and expensive, failing to meet practical measurement needs.

[0003] Therefore, this utility model proposes a PFA pressure guide tube differential pressure sensor. Summary of the Invention

[0004] The purpose of this invention is to propose a PFA pressure guide tube differential pressure sensor, which aims to solve or improve the above-mentioned technical problems.

[0005] To achieve the above objectives, this utility model provides the following solution: This utility model proposes a PFA pressure-conducting tube differential pressure sensor, comprising:

[0006] The outer casing has a communication port at its bottom, and a self-locking ball-shaped check valve is installed on the communication port;

[0007] Inner shell;

[0008] End caps, the end caps comprising an upper end cap and a lower end cap respectively disposed at the upper bottom and lower bottom of the inner shell;

[0009] The PFA pressure guide tube is disposed on the upper end cap and the lower end cap. A sealing component is provided at the upper end of the PFA pressure guide tube, and a first pressure guide hole and a second pressure guide hole are provided on the side wall of the PFA pressure guide tube.

[0010] The air chamber includes an upper air chamber and a lower air chamber disposed within the outer shell. The upper end and lower end of the PFA pressure guiding tube pass through the inner shell sidewall and extend into the upper air chamber and the lower air chamber, respectively. The first pressure guiding hole communicates with the upper air chamber, and the second pressure guiding hole communicates with the lower air chamber. A pressure measuring range is formed between the first pressure guiding hole and the second pressure guiding hole.

[0011] A piston is disposed inside the PFA pressure guide tube, and a magnetic disk is installed at the bottom of the piston;

[0012] A base plate, wherein the base plate is disposed within the lower end cover;

[0013] An eddy current probe, wherein the eddy current probe is mounted on the base plate;

[0014] A buffer assembly is installed at the bottom of the upper end cover and the lower end cover.

[0015] According to the PFA pressure guide tube differential pressure sensor provided by this utility model, the housing includes an upper housing and a lower housing. The bottom of the lower housing has a connecting port, and a self-locking ball-shaped one-way valve is installed on the connecting port. A large sealing ring is provided inside the housing.

[0016] According to the PFA pressure guide tube differential pressure sensor provided by this utility model, the side wall of the inner shell is provided with a first connecting hole and a second connecting hole, and the upper bottom and lower bottom of the inner shell are provided with connecting ports.

[0017] According to the PFA pressure guiding tube differential pressure sensor provided by this utility model, the upper end cover has a first through hole at the center position, the lower end cover has a second through hole at the center position, the upper end cover is sleeved on the top end of the PFA pressure guiding tube, the lower end cover is sleeved on the bottom end of the PFA pressure guiding tube, and the sealing assembly includes a sealing gasket and two small sealing rings.

[0018] According to the PFA pressure guide tube differential pressure sensor provided by this utility model, the buffer assembly includes an upper buffer spring and a lower buffer spring. Both the upper buffer spring and the lower buffer spring are located inside the PFA pressure guide tube. One end of the upper buffer spring is fixedly connected to the upper end cover, and one end of the lower buffer spring is fixedly connected to the base plate.

[0019] According to the PFA pressure guide tube differential pressure sensor provided by this utility model, the distance between the bottom end of the upper buffer spring and the first pressure guide hole is equal to the height of the piston, the distance between the top end of the lower buffer spring and the second pressure guide hole is equal to the height of the piston, and the elastic force of the upper buffer spring and the lower buffer spring is not less than the sum of the weight of the piston and the magnetic disk and the sum of the static friction force between the piston and the PFA pressure guide tube.

[0020] This utility model discloses the following technical effects: During operation, one end of the lower air chamber is connected to the corresponding detection environment via a self-locking ball-shaped check valve. When the pressure being measured in the detection environment is greater than the pressure inside the lower air chamber, the self-locking ball-shaped check valve opens, connecting the external detection environment to the lower air chamber. The upper air chamber is connected to the lower air chamber via the first and second pressure-conducting holes on the side wall of the PFA pressure-conducting pipe. The upper and lower air chambers form a pressure equalization field, balancing internal and external pressures. The piston is within the pressure measurement range, blocking the first and second pressure-conducting holes, and the self-locking ball-shaped check valve self-locks.

[0021] When this invention is in operation, if the ambient air pressure fluctuates, the measured pressure exceeds the sum of the weight of the piston and the magnetic disk plus the frictional force generated by them. This disrupts the pressure balance between the upper and lower air chambers, pushing the piston towards the lower pressure side due to the pressure difference. When the change in ambient air pressure exceeds the pressure measurement range, the piston moves to the upper end of the PFA pressure guide tube. At this point, the upper air chamber is connected to the lower air chamber through the first and second pressure guide holes on the side wall of the PFA pressure guide tube. After the pressures of the upper and lower air chambers are balanced, if the pressure in the upper air chamber is higher than that in the lower air chamber and the ambient air pressure, the piston moves away from the upper end of the PFA pressure guide tube under the action of the upper buffer spring and the pressure of the two air chambers, entering the pressure measurement range of the PFA pressure guide tube, while simultaneously disconnecting the connection between the upper and lower air chambers.

[0022] When this invention is in operation, when the piston is pushed to the lower end of the PFA pressure guide tube by the pressure of the upper air chamber, the first and second pressure guide holes on the PFA pressure guide tube open, connecting the upper and lower air chambers with the external detection environment and establishing a new pressure balance. At this time, the self-locking ball-type one-way valve is activated. Under the action of the lower buffer spring and the external detection environment pressure, the piston leaves the lower end of the PFA pressure guide tube and enters the pressure measurement range of the PFA pressure guide tube, simultaneously disconnecting the connection between the upper and lower air chambers. Due to its own weight and the weight of the magnetic disk, the piston falls to the bottom of the PFA pressure guide tube, thereby achieving the purpose of sealing the second pressure guide hole.

[0023] This invention, through the design of an upper and lower air chamber, effectively isolates the sensor from the erosion and contamination caused by harsh external pressure fields, making it extremely convenient for field use and effectively ensuring the accuracy of differential pressure measurements.

[0024] This invention uses a PFA pressure-conducting tube and a piston as sensing elements, and utilizes an eddy current probe to detect changes in pressure difference. Compared with differential pressure sensors with electronic device structures, it has a simple structure and extremely low cost. It can effectively maintain the stability of its structure under pressure fluctuations or temperature changes, and can avoid measurement errors caused by pipeline deformation.

[0025] This invention employs an eddy current differential pressure sensor. By measuring the pressure difference, the piston moves within the pressure measurement range, and the displacement of the magnetic disk connected to the piston changes accordingly. This causes a change in the distribution of the magnetic field, which is detected by the eddy current probe and converted into an electrical signal output to effectively ensure the measurement accuracy of micro differential pressure. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the PFA pressure guide tube differential pressure sensor of this utility model;

[0027] Figure 2 This is a schematic diagram showing the movement of the piston of this utility model.

[0028] Figure 1-2 In the middle, the upper outer shell 1, sealing gasket 2, upper buffer spring 3, upper end cover 4, PFA pressure guide tube 5, piston 6, large sealing ring 7, magnetic disk 8, small sealing ring 9, inner shell 10, eddy current probe 11, lower buffer spring 12, base plate 13, lower end cover 14, self-locking ball check valve 15, and lower outer shell 16. Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0030] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Reference Figure 1-2 This utility model provides a PFA pressure-conducting tube differential pressure sensor, comprising:

[0032] The outer casing has a communication port at the bottom, and a self-locking ball check valve 15 is installed on the communication port.

[0033] Inner shell 10;

[0034] End caps, including an upper end cap 4 and a lower end cap 14 respectively disposed at the upper bottom and lower bottom of the inner shell 10;

[0035] PFA pressure guide tube 5 is installed on the upper end cover 4 and the lower end cover 14. A sealing component is provided at the upper end of the PFA pressure guide tube 5, and a first pressure guide hole and a second pressure guide hole are provided on the side wall of the PFA pressure guide tube 5.

[0036] The air chamber includes an upper air chamber and a lower air chamber disposed inside the outer shell. The upper end and the lower end of the PFA pressure guiding tube 5 pass through the side wall of the inner shell 10 and extend into the upper air chamber and the lower air chamber respectively. The first pressure guiding hole is connected to the upper air chamber, and the second pressure guiding hole is connected to the lower air chamber. A pressure measuring range is formed between the first pressure guiding hole and the second pressure guiding hole.

[0037] Piston 6 is located inside PFA pressure guide tube 5, and a magnetic disk 8 is installed at the bottom of piston 6.

[0038] Base plate 13, which is disposed inside the lower end cover 14;

[0039] Eddy current probe 11 is mounted on base plate 13;

[0040] A buffer assembly is installed at the bottom of the upper cover 4 and the lower cover 14.

[0041] In this utility model, the outer shell includes an upper outer shell 1 and a lower outer shell 16. The bottom of the lower outer shell 16 has a communication port, and a self-locking ball-shaped one-way valve 15 is installed on the communication port. A large sealing ring 7 is provided inside the outer shell.

[0042] In a further optimized design, the inner shell 10 has a first connecting hole and a second connecting hole on its sidewalls, and a connecting opening is provided at the top bottom and bottom bottom of the inner shell 10.

[0043] The scheme is further optimized by providing a first perforation at the center of the upper end cover 4 and a second perforation at the center of the lower end cover 14. The upper end cover 4 is fitted onto the top of the PFA pressure guiding tube 5, and the lower end cover 14 is fitted onto the bottom of the PFA pressure guiding tube 5.

[0044] The present invention employs a buffer assembly including an upper buffer spring 3 and a lower buffer spring 12. Both the upper buffer spring 3 and the lower buffer spring 12 are located inside the PFA pressure guide tube 5. One end of the upper buffer spring 3 is fixedly connected to the upper end cover 4, and one end of the lower buffer spring 12 is fixedly connected to the base plate 13.

[0045] In operation, one end of the lower air chamber is connected to the corresponding detection environment via a self-locking ball-shaped check valve 15. When the pressure to be measured in the detection environment is greater than the pressure in the lower air chamber, the self-locking ball-shaped check valve 15 is opened, connecting the external detection environment to the lower air chamber. The upper air chamber is connected to the lower air chamber via the first and second pressure guiding holes on the side wall of the PFA pressure guiding pipe 5. The upper and lower air chambers form a pressure equalization field with internal and external pressure balance. The piston 6 is within the pressure measurement range, blocking the first and second pressure guiding holes, and the self-locking ball-shaped check valve 15 self-locks.

[0046] When this invention is in operation, if the ambient air pressure fluctuates, the measured pressure is greater than the sum of the weight of the piston 6 and the magnetic disk 8 plus the frictional force generated by them. This causes the pressure balance between the upper and lower air chambers to be broken, and the piston 6 is pushed to the lower pressure end by the pressure difference. When the change in ambient air pressure exceeds the pressure measurement range, the piston 6 moves to the upper end of the PFA pressure guide tube 5. At this time, the upper air chamber is connected to the lower air chamber through the first and second pressure guide holes on the side wall of the PFA pressure guide tube 5. After the pressure in the upper and lower air chambers is balanced, when the pressure in the upper air chamber is higher than that in the lower air chamber and the ambient air pressure, under the action of the upper buffer spring 3 and the pressure of the two air chambers, the piston 6 leaves the upper end of the PFA pressure guide tube 5 and enters the pressure measurement range of the PFA pressure guide tube 5, while simultaneously disconnecting the connection between the upper and lower air chambers.

[0047] When this invention is in operation, when the piston 6 is pushed to the lower end of the PFA pressure guide tube 5 by the pressure of the upper air chamber, the first and second pressure guide holes on the PFA pressure guide tube 5 open, and the upper and lower air chambers are connected to the external detection environment, establishing a new pressure balance. At this time, the self-locking ball-type one-way valve 15 is turned on. Under the action of the lower buffer spring 12 and the pressure of the external detection environment, the piston 6 leaves the lower end of the PFA pressure guide tube 5 and enters the pressure measurement range of the PFA pressure guide tube 5, while simultaneously cutting off the connection between the upper and lower air chambers. Due to its own weight and the weight of the magnetic disk 8, the piston 6 falls to the bottom of the PFA pressure guide tube 5, thereby achieving the purpose of sealing the second pressure guide hole.

[0048] The scheme is further optimized so that the distance between the bottom end of the upper buffer spring 3 and the first pressure guide hole is equal to the height of the piston 6, and the distance between the top end of the lower buffer spring 12 and the second pressure guide hole is equal to the height of the piston 6.

[0049] To further optimize the scheme, the elastic force of the lower buffer spring 12 should not be less than the sum of the weights of the piston 6 and the magnetic disk 8 and the sum of the static friction between the piston 6 and the PFA pressure guide tube 5. At the same time, the elastic force of the upper buffer spring 3 should be less than the pressure measuring range and greater than the sum of the weights of the piston 6 and the magnetic disk 8 and the static friction between the piston 6 and the PFA pressure guide tube 5.

[0050] The self-locking ball check valve 15 and the eddy current probe 11 are selected from existing technologies. This embodiment does not make specific limitations on the specific models.

[0051] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0052] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A PFA pressure-conducting tube differential pressure sensor, characterized in that, include: The outer casing has a communication port at its bottom, and a self-locking ball check valve (15) is installed on the communication port. Inner shell (10); End caps, the end caps including an upper end cap (4) and a lower end cap (14) respectively disposed on the upper bottom and lower bottom of the inner shell (10); PFA pressure guide tube (5), the PFA pressure guide tube (5) is disposed on the upper end cover (4) and the lower end cover (14), the upper end of the PFA pressure guide tube (5) is provided with a sealing component, and the side wall of the PFA pressure guide tube (5) is provided with a first pressure guide hole and a second pressure guide hole; The air chamber includes an upper air chamber and a lower air chamber disposed within the outer shell. The upper and lower ends of the PFA pressure guiding tube (5) pass through the side wall of the inner shell (10) and extend into the upper air chamber and the lower air chamber, respectively. The first pressure guiding hole communicates with the upper air chamber, and the second pressure guiding hole communicates with the lower air chamber. A pressure measuring range is formed between the first pressure guiding hole and the second pressure guiding hole. Piston (6), the piston (6) is disposed inside the PFA pressure guide tube (5), and a magnetic disk (8) is installed at the bottom of the piston (6); A base plate (13) is disposed inside the lower end cover (14); Eddy current probe (11), the eddy current probe (11) is disposed on the base plate (13); A buffer assembly is installed at the bottom of the upper end cover (4) and the lower end cover (14).

2. The PFA pressure-conducting tube differential pressure sensor according to claim 1, characterized in that: The outer casing includes an upper outer casing (1) and a lower outer casing (16). The lower outer casing (16) has a communication port at its bottom. A self-locking ball-shaped check valve (15) is installed on the communication port. A large sealing ring (7) is provided inside the outer casing.

3. The PFA pressure-conducting tube differential pressure sensor according to claim 2, characterized in that: The inner shell (10) has a first connecting hole and a second connecting hole on its side wall, and the upper bottom and lower bottom of the inner shell (10) have connecting openings respectively.

4. A PFA pressure-conducting tube differential pressure sensor according to claim 3, characterized in that: The upper end cap (4) has a first through hole at its center, and the lower end cap (14) has a second through hole at its center. The upper end cap (4) is fitted onto the top of the PFA pressure guide tube (5), and the lower end cap (14) is fitted onto the bottom of the PFA pressure guide tube (5). The sealing assembly includes a sealing gasket (2) and two small sealing rings (9).

5. A PFA pressure-conducting tube differential pressure sensor according to claim 4, characterized in that: The buffer assembly includes an upper buffer spring (3) and a lower buffer spring (12). Both the upper buffer spring (3) and the lower buffer spring (12) are located inside the PFA pressure guide tube (5). One end of the upper buffer spring (3) is fixedly connected to the upper end cover (4), and one end of the lower buffer spring (12) is fixedly connected to the base plate (13).

6. A PFA pressure-conducting tube differential pressure sensor according to claim 5, characterized in that: The distance between the bottom end of the upper buffer spring (3) and the first pressure guiding hole is equal to the height of the piston (6). The distance between the top end of the lower buffer spring (12) and the second pressure guiding hole is equal to the height of the piston (6). The elastic force of the upper buffer spring (3) and the lower buffer spring (12) is not less than the sum of the weight of the piston (6) and the magnetic disk (8) and the sum of the static friction between the piston (6) and the PFA pressure guiding tube (5).

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