Single-die differential pressure sensor

Abstract

The utility model relates to the technical field of differential pressure sensors, in particular to a single-die differential pressure sensor which comprises a shell and a sealing block, an electrical connector is arranged on the shell, a pressure cavity is defined between the shell and the sealing block, the shell is fixedly connected with the sealing block, and a pressure sensing module is arranged in the pressure cavity. The pressure sensing module divides the pressure chamber into a first chamber and a second chamber, the pressure sensing module comprises a circuit board and a strain gauge, the circuit board is electrically connected to the electrical connector, a sealing piece is arranged between the circuit board and the shell, a sensing notch is formed in the circuit board, the strain gauge is arranged at the sensing notch, and an isolation piece is arranged on the circuit board; the separator is used for isolating direct contact between the strain gauge and gas. The application has the effects of prolonging the service life of the sensor and improving the measurement accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of differential pressure sensors, in particular to a single-mode differential pressure sensor. BACKGROUND

[0002] A differential pressure sensor is a sensor used to measure the difference between two pressures. A differential pressure sensor is usually composed of two parts: one device is placed on the high pressure side (the measured fluid side), and the other device is placed on the low pressure side (the reference fluid side). Differential pressure sensors are generally used to measure the pressure difference between the front and back of a device or component.

[0003] In the automotive field, in order to meet the emission standard requirements, the common method is to install a particulate trap in the exhaust emission part of the automobile to capture particulate matter emitted in the exhaust. However, the exhaust emission channel will be gradually blocked with the accumulation of trapped particles. The method to remove these accumulated particles is to increase the temperature of the exhaust gas to promote the catalyst reaction, thereby causing the accumulated particles to burn and vaporize. This cleaning process is called a "regeneration" process. A differential pressure sensor is installed at both ends of the particulate trap to measure the pressure difference between the inlet and outlet and determine the regeneration time and other information.

[0004] A differential pressure sensor disclosed in Chinese Patent No. CN104764560A includes an upper cover, a lower cover, and a PCB circuit board. The upper cover is arranged on the lower cover. One side of the PCB circuit board is sealed in the upper cover to seal and separate the upper and lower pressure cavities to form a high pressure cavity and a low pressure cavity. Pressure difference measurement holes are formed on the PCB circuit board corresponding to the positions of the upper and lower pressure cavities. A differential pressure sensing chip is installed outside the pressure difference measurement holes.

[0005] Since the high-temperature gas mainly contains nitrogen oxides (NOx) and particulate matter, the nitrogen oxides (NOx) and water vapor in the high-temperature gas will adhere to the differential pressure sensing chip to form an acidic solution. The sealing of the PCB circuit board is usually achieved by using adhesive. The acidic solution will corrode the adhesive part of the differential pressure sensing chip, resulting in poor sealing of the differential pressure sensing chip and reducing the detection accuracy of the sensor. Therefore, there is a problem. Utility model content

[0006] In order to improve the problem that the sealing adhesive on the differential pressure sensing chip is easily corroded by high-temperature gas, resulting in reduced detection accuracy of the sensor, the present application provides a single-mode differential pressure sensor.

[0007] The single-mode differential pressure sensor provided by the present application adopts the following technical solution:

[0008] The utility model provides a single mode pressure difference sensor, including the casing and the block, be provided with electrical connector on the casing, the casing with the block fixed connection between the casing and the block is surrounded pressure chamber, be provided with pressure sensing module in the pressure chamber, pressure sensing module divides the pressure chamber into first chamber and second chamber, pressure sensing module includes circuit board and strain gauge, circuit board is connected to the electrical connector, be provided with sealing element between the circuit board and the casing, be provided with sensing notch on the circuit board, strain gauge sets up at sensing notch, be provided with isolating element on the circuit board, and the isolating element is used to isolate the direct contact of strain gauge and gas.

[0009] By adopting the above technical scheme, the isolating element separates the gas flowing into the first chamber and the second chamber, and the pressure difference of the gas flowing into the first chamber and the second chamber causes the strain gauge to deform slightly, so that the voltage on the strain gauge changes. The strain gauge feeds back the voltage change to the circuit board, and transmits the voltage change of the strain gauge through the electrical connector. In this way, the pressure difference of the gas flowing into the first inlet pipe and the second inlet pipe is measured. The isolating element prevents the gas in the first chamber from contacting the gas in the second chamber, thereby improving the accuracy of the strain gauge measurement.

[0010] Optionally, the casing is provided with a first inlet pipe and a second inlet pipe, the first inlet pipe communicates with the first chamber, the second inlet pipe communicates with the second chamber, and the block is provided with a ventilation groove, one end of the ventilation groove communicates with the second inlet pipe, and the other end of the ventilation groove communicates with the second chamber.

[0011] By adopting the above technical scheme, the gas flowing out of the second inlet pipe flows into the second chamber through the ventilation groove, thereby reducing the difficulty of processing the gas flow channel and facilitating the distribution of the gas flowing out of the first inlet pipe and the second inlet pipe on both sides of the strain gauge.

[0012] Optionally, the sealing element includes a first sealing ring and a second sealing ring symmetrically arranged on both sides of the circuit board, the first sealing ring is located between the circuit board and the first chamber, the second sealing ring is located between the circuit board and the block, and the sensing notch is located in the first sealing ring.

[0013] By adopting the above technical scheme, the first sealing ring and the second sealing ring reduce the possibility of mutual flow of the gas in the first chamber and the second chamber, which is conducive to forming a pressure difference between the first chamber and the second chamber.

[0014] Optionally, the isolating element includes a sealing glass layer arranged on the side of the strain gauge close to the circuit board, and the edge of the sealing glass layer is fixed on the strain gauge.

[0015] By adopting the technical scheme, the sealing glass layer seals the strain gauge, thereby reducing the possibility of the strain gauge directly contacting the measured gas, and the strain gauge can be made of ceramic material, thereby reducing the influence of the gas pressure difference on the measurement accuracy of the strain gauge.

[0016] Optionally, a fixing member is arranged between the shell and the sealing block, and the fixing member comprises an adhesive filled between the shell and the sealing block.

[0017] By adopting the technical scheme, an assembler can quickly fix the sealing block on the shell, and the sealing between the shell and the sealing block is conveniently and quickly realized.

[0018] Optionally, the fixing member comprises a sealant filled between the shell and the sealing block, and a sealant groove for accommodating the sealant is arranged between the shell and the sealing block.

[0019] By adopting the technical scheme, after the assembler installs the sealing block on the shell, the assembler fills the sealant in the sealant groove between the shell and the sealing block, so as to fix the sealing block on the shell, thereby realizing the sealing effect between the shell and the sealing block.

[0020] Optionally, the fixing member comprises a fixing plate arranged on the sealing block, a fixing screw is screwed on the fixing plate, the fixing screw fixes the fixing plate on the shell, a sealing groove is arranged between the shell and the sealing block, and a sealing rubber ring is arranged in the sealing groove.

[0021] By adopting the technical scheme, after the assembler installs the sealing block on the shell, the assembler fixes the fixing plate on the shell through the fixing screw, and in this process, the sealing rubber ring is compressed in the sealing groove between the shell and the sealing block, and the sealing rubber ring is deformed by being extruded, thereby realizing the sealing effect between the shell and the sealing block.

[0022] Optionally, the sealing block comprises a first unit block and a second unit block, the pressure sensing module is arranged between the first unit block and the second unit block, the first cavity is arranged on the first unit block, and the second cavity is arranged on the second unit block.

[0023] By adopting the technical scheme, the first unit block and the second unit block are designed in a split manner, which facilitates workers to assemble the pressure sensing module, and is conducive to reducing the difficulty of processing the first cavity and the second cavity.

[0024] In summary, the present application has at least one of the following beneficial technical effects:

[0025] 1. The isolation piece separates the gas flowing into the first chamber and the second chamber, and the pressure difference of the gas flowing into the first chamber and the second chamber causes the strain gauge to be slightly deformed, so that the voltage on the strain gauge changes, the strain gauge feeds back the voltage change to the circuit board, and the voltage change of the strain gauge is transmitted through the electrical connector, so as to realize the measurement of the pressure difference of the gas flowing into the first inlet pipe and the second inlet pipe. In this process, the isolation piece prevents the gas from contacting between the first chamber and the second chamber, thereby improving the accuracy of the strain gauge measurement;

[0026] 2. The sealing glass layer seals the strain gauge, thereby reducing the possibility of direct contact between the strain gauge and the measured gas, and the strain gauge can be made of ceramic material, thereby reducing the influence of gas pressure difference on the measurement accuracy of the strain gauge;

[0027] 3. After the assembler installs the sealing block on the shell, the assembler fills the sealing glue into the molten glue groove between the shell and the sealing block, so as to fix the sealing block on the shell, thereby realizing the sealing effect of the gap between the shell and the sealing block. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic diagram of embodiment 1 of the present application.

[0029] Figure 2 is an explosion schematic diagram of embodiment 1 of the present application.

[0030] Figure 3 is a sectional view of the position relationship of the sealing block, the second sealing ring and the shell in embodiment 1 of the present application.

[0031] Figure 4 is a sectional view of the position relationship of the sealing block, the sealing glue and the shell in embodiment 2 of the present application.

[0032] Figure 5 is a sectional view of the position relationship of the sealing block, the fixed plate and the sealing glue ring in embodiment 3 of the present application.

[0033] Figure 6 is a sectional view of the position relationship of the first unit block, the second unit block and the sealing glue ring in embodiment 4 of the present application.

[0034] Explanation of reference signs: 1, housing; 2, sealing block; 21, first unit block; 22, second unit block; 3, electrical connector; 4, pressure chamber; 41, first chamber; 42, second chamber; 5, fixing member; 51, potting adhesive; 52, molten adhesive groove; 53, fixing plate; 54, fixing screw; 55, sealing groove; 56, sealing rubber ring; 6, pressure sensing module; 61, circuit board; 62, sealing member; 621, first sealing ring; 622, second sealing ring; 63, sensing notch; 64, strain gauge; 65, isolating member; 651, sealing glass layer; 7, first air inlet pipe; 8, second air inlet pipe; 9, air passage. DETAILED DESCRIPTION

[0035] The following description will be made in conjunction with the accompanying drawings. Figures 1-6 The application is further described in detail.

[0036] The application discloses a single-mode differential pressure sensor.

[0037] Embodiment 1

[0038] Referring to Figure 1 , the single-mode differential pressure sensor comprises a housing 1 and a sealing block 2, the housing 1 is integrally formed with an electrical connector 3, a pressure chamber 4 is formed between the housing 1 and the sealing block 2, the sealing block 2 is provided with an air passage 9, and a fixing member 5 is arranged between the housing 1 and the sealing block 2. The fixing member 5 comprises an adhesive (not shown in the figure) filled between the housing 1 and the sealing block 2. The adhesive can be an inorganic resin in the prior art, and the housing 1 and the sealing block 2 can also be fixed by ultrasonic welding.

[0039] Referring to Figure 1 , Figure 2 and Figure 3 , the pressure sensing module 6 is arranged in the pressure chamber 4, the pressure sensing module 6 divides the pressure chamber 4 into a first chamber 41 and a second chamber 42, the housing 1 is welded with a first air inlet pipe 7 and a second air inlet pipe 8, the first air inlet pipe 7 communicates with the first chamber 41, and the second air inlet pipe 8 communicates with the second chamber 42 through the air passage 9.

[0040] Referring to Figure 1 , Figure 2 and Figure 3 , the pressure sensing module 6 comprises a circuit board 61 arranged in the housing 1 and electrically connected to the electrical connector 3, a sealing member 62 is arranged between the circuit board 61 and the housing 1, the circuit board 61 is provided with a sensing notch 63, and a strain gauge 64 is arranged at the sensing notch 63. The strain gauge 64 is made of a high-temperature-resistant flexible material, and is used to block the sensing notch 63.

[0041] Referring to Figure 1 , Figure 2 and Figure 3The circuit board 61 is provided with a spacer 65 for isolating the strain gauge 64 from direct contact with the gas, the spacer 65 comprising a sealing glass layer 651 wrapped around the side of the strain gauge 64 close to the circuit board, the sealing glass layer 651 being made of a flexible material resistant to high temperature, and the edges of the sealing glass layer 651 being bonded to the strain gauge 64.

[0042] With reference to Figure 1 , Figure 2 and Figure 3 , the sealing member 62 comprises a first sealing ring 621 and a second sealing ring 622 symmetrically arranged on both sides of the circuit board 61, the first sealing ring 621 being located between the circuit board 61 and the side wall of the shell 1 of the first chamber 41, and the second sealing ring 622 being located between the circuit board 61 and the sealing block 2, the induction notch 63 being located within the circle of the first sealing ring 621, and the air passage 9 on the sealing block 2 communicating with the second chamber 42 being located within the circle of the second sealing ring 622.

[0043] The construction personnel connect the first air inlet pipe 7 and the second air inlet pipe 8 on the shell 1 to the two ends of the device under test respectively, the gas flowing into the first air inlet pipe 7 will eventually flow into the first chamber 41, and the gas flowing into the second air inlet pipe 8 will flow into the air passage 9 on the sealing block 2, and then flow into the second chamber 42 through the air passage 9 on the sealing block 2, the difference in gas pressure between the first chamber 41 and the second chamber 42 will cause the strain gauge 64 and the sealing glass layer 651 to deform.

[0044] The strain gauge 64 and the sealing glass layer 651 will deform accordingly, and the strain gauge 64 will change its resistance value after deforming, so that the electrical signal fed back by the strain gauge 64 to the circuit board 61 will change, and finally output to the external device through the electrical connector 3, in the process, the strain gauge 64 and the sealing glass layer 651 are wrapped, reducing the direct contact of the strain gauge 64 with the gas, thereby reducing the possibility of damage to the strain gauge 64 caused by corrosion of the gas.

[0045] The implementation principle of the embodiment 1 is that the construction personnel connect the first air inlet pipe 7 and the second air inlet pipe 8 on the shell 1 to the two ends of the device under test respectively, the gas flowing into the first air inlet pipe 7 will eventually flow into the first chamber 41, and the gas flowing into the second air inlet pipe 8 will flow into the air passage 9 on the sealing block 2, and then flow into the second chamber 42 through the air passage 9 on the sealing block 2, the difference in gas pressure between the first chamber 41 and the second chamber 42 will cause the strain gauge 64 and the sealing glass layer 651 to deform.

[0046] The shape of the strain gauge 64 and the sealing glass layer 651 is deformed, and the strain gauge 64 changes its resistance value after deformation, so that the electrical signal fed back to the circuit board 61 by the strain gauge 64 changes, and finally the electrical connector 3 outputs to the external device. In this process, since the strain gauge 64 and the sealing glass layer 651 are wrapped, the direct contact of the strain gauge 64 with the measured gas is reduced, thereby reducing the possibility of damage to the strain gauge 64 caused by corrosion of the gas.

[0047] Embodiment 2

[0048] Reference Figure 1 The difference between this embodiment and embodiment 1 is that the fixing member 5 includes a potting glue 51 filled between the shell 1 and the sealing block 2, a molten glue groove 52 for accommodating the potting glue 51 is arranged between the shell 1 and the sealing block 2, and a plurality of velvet hooks are welded on the side wall of the molten glue groove 52 of the shell 1, and the velvet hooks are located in the potting glue 51.

[0049] The implementation principle of embodiment 2 is that after the assembly personnel install the sealing block 2 on the shell 1, the assembly personnel fills the potting glue 51 in the molten glue groove 52 between the shell 1 and the sealing block 2, and the potting glue 51 wraps the velvet hooks on the shell 1. When the potting glue 51 solidifies, the sealing block 2 is fixed on the shell 1, and the gap between the shell 1 and the sealing block 2 is sealed.

[0050] Embodiment 3

[0051] Reference Figure 2 The difference between this embodiment and embodiment 1 is that the fixing member 5 includes a fixing plate 53 welded on the sealing block 2, a fixing screw 54 is bolted on the fixing plate 53, the fixing screw 54 fixes the fixing plate 53 on the shell 1, a sealing groove 55 is arranged between the shell 1 and the sealing block 2, and a sealing rubber ring 56 is arranged in the sealing groove 55.

[0052] The implementation principle of embodiment 3 is that after the assembly personnel install the sealing block 2 on the shell 1, the assembly personnel fix the fixing plate 53 on the shell 1 through the fixing screw 54. In this process, the fixing plate 53 fixes the sealing block 2 on the shell 1, and at the same time, the sealing rubber ring 56 is compressed in the sealing groove 55 between the shell 1 and the sealing block 2. The sealing rubber ring 56 is deformed by being extruded, so that the gap between the shell 1 and the sealing block 2 is sealed.

[0053] Embodiment 4

[0054] Reference Figure 3 Figure 4 Figure 5 Figure 6The difference between the embodiment and the embodiment 1 is that the sealing block 2 comprises a first unit block 21 and a second unit block 22, the pressure sensing module 6 is arranged between the first unit block 21 and the second unit block 22, the first sealing ring 621 and the second sealing ring 622 are located on both sides of the pressure sensing module 6, the first cavity 41 is opened on the first unit block 21, and the second cavity 42 is opened on the second unit block 22.

[0055] The implementation principle of the embodiment 4 is that the first unit block 21 and the second unit block 22 are designed in a split mode, so that workers can conveniently install the pressure sensing module 6, and the difficulty of processing the first cavity 41 and the second cavity 42 is reduced.

[0056] The above are preferred embodiments of the application, and do not limit the protection scope of the application, so that: any equivalent changes made according to the structure, shape and principle of the application should be covered within the protection scope of the application.

Claims

1. A single-mode differential pressure sensor, characterized in that: The device includes a housing (1) and a sealing block (2). An electrical connector (3) is provided on the housing (1). A pressure chamber (4) is formed between the housing (1) and the sealing block (2). A pressure sensing module (6) is provided in the pressure chamber (4). The pressure sensing module (6) divides the pressure chamber (4) into a first chamber (41) and a second chamber (42). The pressure sensing module (6) includes a circuit board (61) and a strain gauge (64). The circuit board (61) is electrically connected to the electrical connector (3). A sealing element (62) is provided between the circuit board (61) and the housing (1). A sensing slot (63) is opened on the circuit board (61). The strain gauge (64) is located at the sensing slot (63). An isolation element (65) is provided on the circuit board (61). The isolation element (65) is used to isolate the strain gauge (64) from direct contact with the gas.

2. The single-mode differential pressure sensor according to claim 1, characterized in that: The housing (1) is provided with a first air inlet pipe (7) and a second air inlet pipe (8). The first air inlet pipe (7) is connected to the first chamber (41), and the second air inlet pipe (8) is connected to the second chamber (42). The sealing block (2) is provided with a ventilation channel (9). One end of the ventilation channel (9) is connected to the second air inlet pipe (8), and the other end is connected to the second chamber (42).

3. A single-mode differential pressure sensor according to claim 2, characterized in that: The sealing element (62) includes a first sealing ring (621) and a second sealing ring (622) symmetrically arranged on the circuit board (61). The first sealing ring (621) is located between the circuit board (61) and the first chamber (41), and the second sealing ring (622) is located between the circuit board (61) and the sealing block (2). The sensing slot (63) is located inside the first sealing ring (621).

4. A single-mode differential pressure sensor according to claim 1, characterized in that: The isolation element (65) includes a sealing glass layer (651) disposed on the strain gauge (64), and the edge of the sealing glass layer (651) is fixed to the strain gauge (64).

5. A single-mode differential pressure sensor according to claim 1, characterized in that: A fixing member (5) is provided between the housing (1) and the sealing block (2), and the fixing member (5) is used to fix the sealing block (2) on the housing (1).

6. A single-mode differential pressure sensor according to claim 5, characterized in that: The fastener (5) includes an adhesive that fills the space between the housing (1) and the sealing block (2).

7. A single-mode differential pressure sensor according to claim 5, characterized in that: The fastener (5) includes potting compound (51) filled between the housing (1) and the sealing block (2), and a molten adhesive groove (52) is provided between the housing (1) and the sealing block (2) to accommodate the potting compound (51).

8. A single-mode differential pressure sensor according to claim 5, characterized in that: The fixing member (5) includes a fixing plate (53) disposed on the sealing block (2), a fixing screw (54) is bolted on the fixing plate (53), the fixing screw (54) fixes the fixing plate (53) on the housing (1), a sealing groove (55) is provided between the housing (1) and the sealing block (2), and a sealing rubber ring (56) is provided in the sealing groove (55).

9. A single-mode differential pressure sensor according to claim 3, characterized in that: The sealing block (2) includes a first unit block (21) and a second unit block (22). The pressure sensing module (6) is disposed between the first unit block (21) and the second unit block (22). The first chamber (41) is opened on the first unit block (21), and the second chamber (42) is opened on the second unit block (22).

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