All-welded dual-redundancy differential pressure transmitter and method thereof

Abstract

The invention belongs to the technical field of design and manufacturing of differential pressure measuring instruments, and particularly relates to an all-welded dual-redundancy differential pressure transmitter and a welding method thereof. The device comprises a base, a shell, a differential pressure sensor and the like, the two ends of the differential pressure sensor are welded in the shell through laser, the shell is welded with the base, a high-pressure cavity and a low-pressure cavity are formed in the two sides of the sensor, and pressure holes in the base are communicated with the high-pressure cavity and the low-pressure cavity respectively. The upper end of the sensor is sequentially connected with a circuit signal board and an electric connector socket. The welding method comprises the steps of welding of the base and the shell, installation of the sensor in the shell and laser welding, connection and testing of the electric signal plate, welding of the electric connector socket and the like, and parameters can be dynamically adjusted during laser welding. The problem of sealing failure of a traditional O-shaped ring sealing type transmitter is effectively solved, the sealing performance, the measurement precision and the structural stability are improved, the high and low temperature adaptability and the medium compatibility are good, the high-precision differential pressure transmitter is suitable for the field of high-precision differential pressure measurement, and a more reliable and accurate solution is provided for industrial measurement.

Description

Technical Field

[0001] The invention belongs to the technical field of design and manufacturing of differential pressure measuring instruments, and in particular relates to a fully welded dual-redundancy differential pressure transmitter and a method thereof. Background Art

[0002] The dual-redundancy differential pressure transmitter uses two sets of independent differential pressure sensors, which can measure the differential pressure and output signals respectively. This design improves the reliability and accuracy of the measurement. When the medium flows through the differential pressure sensor, the pressure at both ends of the sensor is different due to the different pressures of the fluid at different positions in the pipeline. This pressure difference is sensed by the sensor and converted into an electrical signal. The electrical signal output by the sensor is amplified, linearized, converted, and finally converted into a standard current signal or digital signal for transmission to the control system or display device.

[0003] Dual-redundancy differential pressure transmitters usually use high-quality O-rings to ensure the sealing and reliability of the measured medium. However, due to the limitations of the O-ring seal material, the seal will fail, resulting in damage to the transmitter. The limitations of the O-ring material are shown in the following points: (1) Chemical compatibility issues O-rings fail due to compatibility issues with the measured media (such as chemicals), which manifests as cracks, stains, coloration / discoloration, hardness changes, etc. Different O-rings have different compatibility characteristics with specific chemicals, which may cause the O-ring to become harder or softer, lose strength after softening, or even become distorted.

[0004] (2) Temperature sensitivity In high temperature environments, the hardness of the O-ring will decrease and may even make it impossible to restore to its original shape. In low temperature environments, it is easy to vitrify, thus affecting the high-pressure sealing performance.

[0005] (3) Installation issues Incorrect installation methods can cause the O-ring to twist, and the parting surfaces of the O-ring will be at different levels, which will reduce the sealing effect of the O-ring and even cause leakage.

[0006] In view of the above limitations of O-ring sealing materials, it is almost difficult to find an O-ring material that can meet both high and low temperature environments and most measuring media. Therefore, it is necessary to invent a fully welded differential pressure transmitter. Summary of the invention

[0007] The present invention provides a fully welded dual-redundancy differential pressure transmitter and method thereof to solve the technical problem in the prior art that the O-ring seal used in the differential pressure transmitter is easily affected by external factors and deformed, thereby affecting the high-pressure sealing performance and even causing leakage.

[0008] In order to achieve the above object, the present invention adopts the following technical solution: A fully welded dual-redundancy differential pressure transmitter includes a differential pressure sensor. Both ends of the differential pressure sensor are laser welded inside a base. A sealed cavity is formed between the two sides of the differential pressure sensor and the base, one is a high-pressure cavity and the other is a low-pressure cavity. The upper end of the differential pressure sensor is connected to an electrical signal board, and the upper end of the electrical signal board is connected to an electrical connector socket.

[0009] Both ends of the differential pressure sensor are cylindrical terrace structures, and the outer diameter of one end forming a high-pressure chamber is greater than the outer diameter of one end forming a low-pressure chamber.

[0010] The outer side of the base is sleeved with a shell, and the lower end of the shell is fixed on the base by laser welding. Two pressure holes are processed in the base, one is connected to the high-pressure chamber, and the other is connected to the low-pressure chamber.

[0011] A step hole is arranged in the base, and two ends of the differential pressure sensor are respectively fixed in the step hole by laser welding.

[0012] Cover holes are also arranged on the side walls at both ends of the base, the cover holes are communicated with the step holes, and cover plates are welded in the cover holes.

[0013] The output end of the differential pressure sensor is connected to the circuit signal board through a cable. The circuit signal board is placed on the circuit pad. The circuit signal board and the circuit pad are fixed to the upper end of the base through screws.

[0014] The cover plate, the differential pressure sensor and the base form a closed cavity at each end of the differential pressure sensor.

[0015] The circuit signal board is connected to the electric connector socket through a cable, and the lower end of the outer periphery of the electric connector socket is welded on the shell.

[0016] A welding method for a fully welded dual-redundancy differential pressure transmitter comprises the following steps: The differential pressure sensor is installed in the base, and the two ends of the differential pressure sensor are welded inside the base by intelligent laser. During the intelligent laser welding process, the laser welding beam focus size and welding rate can be dynamically adjusted; Use screws to fix the electrical signal board to the upper end of the base, connect the cable at the output end of the differential pressure sensor to the point signal board, and test whether the electrical signal transmission is correct; Connect the electrical signal board to the electrical connector socket via a cable.

[0017] During intelligent laser welding, the weld pool status of the welding part is monitored in real time, including the weld pool width W and the weld pool depth H of the weld cross section. The power of the laser welding device and the size and shape of the laser beam focal spot are adjusted according to the ratio of the weld pool width W and the weld pool depth H. The smaller the ratio of the weld pool width W and the weld pool depth H, the control system increases the laser welding power, and vice versa.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a fully welded dual-redundancy differential pressure transmitter, which adopts a fully welded structure, laser welds the two ends of the differential pressure sensor inside the base, and the housing and the base are also fixed by laser welding. Compared with the traditional O-ring sealing method, it effectively avoids the sealing failure problem caused by the limitations of the sealing material (such as chemical compatibility, temperature sensitivity, installation problems, etc.). The welding structure can better adapt to various complex working conditions, such as high and low temperature environments, different chemical media, etc., to ensure that the measured medium will not leak, improve the overall sealing performance of the transmitter, and enhance the reliability and stability of the product.

[0019] Furthermore, the differential pressure sensor, the base and the cover plate form a high-pressure chamber and a low-pressure chamber on both sides of the differential pressure sensor, and cover holes are provided on the two side walls of the base, and the cover plate is welded in the cover holes to form a sealed pressure chamber, so that the pressure transmission is more accurate and the accuracy of the differential pressure measurement is ensured.

[0020] Furthermore, both ends of the differential pressure sensor are cylindrical stepped structures, and the outer diameter of the high-pressure chamber end is larger than the outer diameter of the low-pressure chamber end. This design is not only convenient for installation and error prevention, but also enables the sensor to better adapt to pressure changes after welding, thereby improving the sensor's perception accuracy of pressure differences and thus improving measurement accuracy.

[0021] Furthermore, the present invention discloses a welding method for a fully welded dual-redundancy differential pressure transmitter. During the intelligent laser welding process, the laser welding parameters (power, beam focal spot size and shape, etc.) can be dynamically adjusted according to the real-time monitored weld pool status (such as the ratio of weld pool width and depth), thereby ensuring the consistency and stability of the weld quality, reducing the impact of the welding process on the sensor accuracy, and enabling the differential pressure sensor to more accurately convert the pressure difference into an electrical signal, and obtain more accurate measurement results after processing by a circuit signal board. The application of intelligent laser welding technology makes the welding process more automated and precisely controllable, reduces manual intervention and human errors, improves the stability of the production process and the repeatability of product quality, and facilitates production management and quality control.

[0022] Furthermore, the overall welding structure enables the components to form a solid whole, reduces the relative displacement and looseness between the components, improves the anti-interference ability of the transmitter in harsh environments such as vibration and impact, enhances the mechanical stability of the product, and ensures reliable operation under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : Three-dimensional diagram of fully welded dual-redundancy differential pressure transmitter; Figure 2 : Schematic diagram of the differential pressure sensor structure; Figure 3 : Schematic diagram of assembly analysis of fully welded dual-redundancy differential pressure transmitter; Figure 4 : Exploded view of fully welded dual-redundant differential pressure transmitter; Figure 5 : Three-dimensional image of the base.

[0024] Explanation of reference numerals: 1. Electrical connector socket; 2. Shell; 3. Screw; 4. Circuit signal board; 5. Circuit pad; 6. Cover plate; 7. Differential pressure sensor; 8. Cable; 9. Base; 10. Pin; 11. Step hole; 12. Cover hole. DETAILED DESCRIPTION

[0025] In order to further understand the content of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.

[0026] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0027] See also Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 , a three-dimensional diagram of the present invention, which shows the overall appearance structure of the fully welded dual-redundancy differential pressure transmitter. Figure 1 It can be clearly seen that the electrical connector socket 1 is arranged at the upper end of the housing 2, and is used to connect to an external device to transmit signals. The housing 2 is cylindrical in shape, providing protection and sealing space for internal circuits and sensors. Figure 2 The differential pressure sensor structure in the transmitter. The differential pressure sensor is the core component of the transmitter. It is in the shape of a column structure with a certain height and diameter. The structural difference between the high-pressure end and the low-pressure end can be observed in the figure. The outer diameter of the cylinder at the high-pressure end is larger than that at the low-pressure end. Figure 3The assembly cross-sectional view of the present invention clearly reveals the assembly relationship of the various components inside the transmitter. The housing 2 is sleeved on the outside of the base 9, the lower end of the housing 2 is welded to the base 9, and a pin 10 is welded to the bottom of the base 9; a circular step hole 11 corresponding to the column structure shape at both ends of the differential pressure sensor 7 is provided in the base 9, and two differential pressure sensors 7 are welded in the step holes 11 on the base 9 in an upper and lower distribution. Cover holes 12 are also provided on the side walls at both ends of the base 9, as shown in FIG. Figure 5 As shown in , the cover hole 12 is connected to the step hole 11, the cover plate 6 is welded in the cover hole 12, the circuit signal board 4 is placed on the circuit pad 5, the circuit signal board 4 and the circuit pad 5 have screw holes of the same position and size, and the circuit signal board 4 and the circuit pad 5 are fixed to the upper end of the base 9 by four screws 3; the two differential pressure sensors 7 are connected by a cable 8, and the output end of the upper differential pressure sensor 7 is connected to the circuit signal board 4 through the cable 8 passing through the circuit pad 5, and the cable 8 at the output end of the circuit signal board 4 is connected to the electrical connector socket 1 at its upper end; the overall structure composed of the circuit signal board 4, the circuit pad 5, the cover plate 6 and the differential pressure sensor 7 is located inside the shell 2, and the electrical connector socket 1 is welded to the shell 2, providing a reliable interface for signal output. Figure 4 In the exploded diagram of the structure of the present invention, the various components of the transmitter are disassembled and displayed, which more intuitively presents the shape, position and interconnection relationship of each component. From the figure, it can be clearly seen that the electrical connector socket 1, the housing 2, the screw 3, the circuit signal board 4, the circuit pad 5, the cover plate 6, the differential pressure sensor 7, the cable 8, the base 9 and the pin 10 and other components. During assembly, the pin 10 is first welded to the bottom of the base 9, and then the differential pressure sensor 7, the cover plate 6, the circuit signal board 4, the circuit pad 5, the housing 2 and the electrical connector socket 1 are installed in sequence to complete the assembly of the entire transmitter.

[0028] Example 1 This embodiment provides a fully welded dual-redundancy differential pressure transmitter and method thereof, and the specific implementation steps are as follows: In the industrial automation control project, it is necessary to accurately measure and monitor the fluid pressure in a complex chemical production process, and the fully welded dual-redundancy differential pressure transmitter of the present invention is used. The outer diameters of the two ends of the differential pressure sensor 7 are different, one end has a large diameter and the other end has a small diameter. The end with a large diameter is the high-pressure end, and the end with a small diameter is the low-pressure end. This design not only realizes error-proof installation, but also facilitates welding with the base, ensuring that there will be no wrong connection during the installation process, while ensuring the convenience and accuracy of welding, thereby playing a key role in improving the performance and reliability of the entire transmitter. The base 9 and the differential pressure sensor 7 are made of titanium alloy materials with lower thermal conductivity, and combined with the high absorption rate of titanium alloy to laser, the heat conduction range during welding is effectively reduced, while ensuring the consistency of the thermal conductivity of the base and the sensor, thereby further improving the accuracy and stability of the sensor without sacrificing the welding quality. The electrical connector socket 1 uses an aviation plug-type connector to ensure the stability of signal transmission. Before installation, all parts are strictly quality inspected. The differential pressure sensor 7 is precisely calibrated to ensure its measurement accuracy. The calibration equipment uses a high-precision pressure calibrator (accuracy is ±0.02%FS). Non-destructive testing (such as ultrasonic testing) is performed on the base 9, shell 2 and other welding parts to ensure that there are no defects such as cracks and pores. At the same time, check whether the circuit connection of the circuit signal board 4 and the circuit pad 5 is normal, and whether the components such as resistors and capacitors meet the design requirements.

[0029] First, fix the pin 10 to the bottom of the base 9 by laser welding to ensure that the pin 10 is firmly fixed; install the two differential pressure sensors 7 into the base 9, and weld the two ends of the differential pressure sensor 7 to the step hole 11 of the base 9 by laser welding. Install the cover plate 6 in the cover hole 12 connected to the step hole 11, and fix the cover plate 6 in the cover hole 12 of the base 9 by welding. After welding, the cover plate, the differential pressure sensor and the base form a closed cavity at both ends of the differential pressure sensor, and form a high-pressure cavity and a low-pressure cavity on both sides of the differential pressure sensor 7. The structure of these two cavities is complete, the cavity wall thickness is uniform, and the pressure can be effectively transmitted. Place the circuit signal board 4 on the circuit pad 5. The circuit signal board 4 and the circuit pad 5 have the same position and number of screw holes. The circuit signal board 4 and the circuit pad 5 are fixed to the upper end of the base 9 by 4 screws 3. The screws 3 are evenly distributed to ensure the stability of the connection. At the same time, pay attention to the tightening torque of the screw 3 to prevent over-tightening or over-loosening from affecting the circuit performance. The upper and lower differential pressure sensors 7 are connected by a cable 8. The cable 8 at the output end of the upper differential pressure sensor 7 is connected to the circuit signal board 4 through the circuit pad 5 to ensure reliable connection and normal signal transmission; the circuit signal board 4 is connected to the welding cup of the upper electrical connection socket 1 through the cable 8 to ensure a firm connection and good electrical conduction. The shell 2 is sleeved on the outside of the base 9, and the lower end of the shell 2 is welded on the base 9 to form a closed space, which wraps the circuit board and the signal transmission cable, isolating it from the external space, effectively preventing dust, moisture and other impurities from entering, and ensuring the normal operation of the internal circuit and sensor. Then the electrical connector socket 1 is welded to the shell 2 to ensure the welding quality, so that the closed space formed by the shell 2, the base 9 and the electrical connector socket 1 after welding can effectively wrap the circuit board and the signal transmission cable, realize the transmission and processing of the signal, achieve good isolation from the external space, and play a role in sealing and dust prevention.

[0030] Example 2 In this embodiment, the differential pressure sensor 7 and the base 9 are welded by intelligent laser welding. A weld monitoring device is installed on the laser welding device. During the welding process, the control system dynamically adjusts the laser welding power and the size of the beam focus on the surface of the welding part according to the real-time welding status and the information fed back by the integrated welding monitoring device. The weld monitoring device monitors the weld pool status of the welding part in real time, including the weld pool width W and the weld pool depth H of the weld cross section. The weld monitoring device sends the monitored weld pool width W and the weld pool depth H data to the control system. The control system adjusts the power of the laser welding device and the size and shape of the laser beam focus according to the ratio of the weld pool width W and the weld pool depth H. The smaller the ratio of the weld pool width W and the weld pool depth H, the control system increases the laser welding power. Conversely, the control system decreases the laser welding power. Since the weld surface is not a smooth plane, the area of ​​the beam focus on the weld surface is not equal. The effects are different. In order to ensure that the focal spot area of ​​the beam on the weld surface is the same, the control system is equipped with a fixed distance between the laser light source and the weld surface. The welding monitoring device monitors the real-time distance between the laser light source and the weld surface, and sends the trial distance data to the control system. The control system compares the two data. If the real-time distance is less than or greater than the fixed distance, the control system controls the laser welding device to rise or fall until the real-time distance is equal to the set fixed distance, thereby ensuring the quality of the weld, avoiding welding stability problems caused by uneven beam focal spot size, and achieving more precise welding.

[0031] During the entire project operation, the fully welded dual-redundant differential pressure transmitter demonstrated excellent performance, effectively avoiding the problems caused by traditional O-ring sealing methods, and providing reliable pressure measurement guarantees for the stable operation of the chemical production process.

[0032] In a preferred embodiment of the present invention, before each structure is welded and assembled, the differential pressure sensor 7 and the base 9 are placed in a preheating oven to preheat the differential pressure sensor 7 and the base 9. The preheating adopts multi-layer preheating, and infrared thermal imaging is used to monitor the preheating effect in real time to ensure that the preheating is uniform and reaches the optimal temperature range. The optimal temperature range is: 150℃-165℃, thereby effectively reducing the temperature gradient during welding, so as to reduce the influence of thermal stress and welding heat conduction on welding quality.

[0033] In a further preferred embodiment, the welding method between the base 9 and the shell 2, the shell 2 and the electrical connector socket 1, and the cover plate 6 and the shell 2 can also be selected as automatic argon arc welding. Argon arc welding can effectively isolate the adverse effects of oxygen, nitrogen, hydrogen, etc. in the air on the arc and the molten pool, avoid the stress concentration problem caused by poor weld formation, and thus improve the stability of the entire structure. At the same time, the use of argon arc welding in the above-mentioned parts can also reduce processing costs; and for the welding of the differential pressure sensor 7, which is more sensitive to heat conduction and has higher welding requirements, intelligent laser welding is required; in the manufacture of the fully welded dual-redundancy differential pressure transmitter, argon arc welding and laser welding complement each other. According to the welding requirements of different components, production scale, cost control and other factors, the appropriate welding method can be flexibly selected to achieve the best production effect and product performance.

[0034] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A fully welded dual-redundancy differential pressure transmitter, characterized in that: The differential pressure sensor (7) comprises two ends of the differential pressure sensor (7) which are laser welded inside a base (9), a sealed cavity is formed between the two sides of the differential pressure sensor (7) and the base (9), one is a high-pressure cavity, and the other is a low-pressure cavity, the upper end of the differential pressure sensor (7) is connected to an electric signal board (4), and the upper end of the electric signal board (4) is connected to an electric connector socket (1).

2. A fully welded dual-redundancy differential pressure transmitter according to claim 1, characterized in that: Both ends of the differential pressure sensor (7) are cylindrical step structures, and the outer diameter of one end forming the high-pressure chamber is larger than the outer diameter of one end forming the low-pressure chamber.

3. A fully welded dual-redundancy differential pressure transmitter according to claim 2, characterized in that: The outer side of the base (9) is sleeved with a shell (2), and the lower end of the shell (2) is fixed to the base (9) by laser welding. Two pressure holes are machined in the base (9), one of which is connected to the high-pressure chamber and the other is connected to the low-pressure chamber.

4. The fully welded dual-redundancy differential pressure transmitter according to claim 1, characterized in that: The base (9) is provided with a stepped hole (11), and two ends of the differential pressure sensor (7) are respectively fixed in the stepped hole (11) by laser welding.

5. A fully welded dual-redundancy differential pressure transmitter according to claim 4, characterized in that: Cover holes (12) are also provided on the side walls at both ends of the base (9); the cover holes (12) are connected to the step holes (11), and a cover plate (6) is welded inside the cover holes (12).

6. A fully welded dual-redundancy differential pressure transmitter according to claim 5, characterized in that: The output end of the differential pressure sensor (7) is connected to the circuit signal board (4) via a cable (8); the circuit signal board (4) is placed on the circuit pad (5); the circuit signal board (4) and the circuit pad (5) are fixed to the upper end of the base (9) via screws (3).

7. A fully welded dual-redundancy differential pressure transmitter according to claim 6, characterized in that: The cover plate (6), the differential pressure sensor (7) and the base (9) form a closed cavity at each end of the differential pressure sensor (7).

8. A fully welded dual-redundancy differential pressure transmitter according to claim 7, characterized in that: The circuit signal board (4) is connected to the electrical connector socket (1) via a cable (8), and the lower end of the outer periphery of the electrical connector socket (1) is welded to the housing (2).

9. A welding method for a fully welded dual-redundancy differential pressure transmitter, based on a fully welded dual-redundancy differential pressure transmitter according to any one of claims 1 to 8, characterized in that: The following steps are involved: The differential pressure sensor (7) is installed in the base (9), and the two ends of the differential pressure sensor (7) are welded to the inside of the base (9) by using an intelligent laser. During the intelligent laser welding process, the laser welding beam focal spot size and welding rate can be dynamically adjusted; Use screws to fix the electric signal board (4) to the upper end of the base (9), connect the cable at the output end of the differential pressure sensor (7) to the point signal board (4), and test whether the electric signal transmission is correct; The electric signal board (4) is connected to the electric connector socket (1) via a cable (8).

10. The welding method of a fully welded dual-redundancy differential pressure transmitter according to claim 9, characterized in that: During the intelligent laser welding, the weld pool state of the welding part is monitored in real time, including the weld pool width W and the weld pool depth H of the weld cross section. The power of the laser welding device and the size and shape of the laser beam focal spot are adjusted according to the ratio of the weld pool width W and the weld pool depth H. The smaller the ratio of the weld pool width W and the weld pool depth H, the control system increases the laser welding power, and vice versa.

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