Differential pressure transmitting device

Abstract

The invention relates to the technical field of transmitters, in particular to a pressure difference transmitting device which comprises a hydraulic body, and an upstream hydraulic channel and a downstream hydraulic channel are arranged in the hydraulic body. The sealing mechanism isolates the high-pressure cavity from the low-pressure cavity when the first pressure detection unit and the second pressure detection unit perform air pressure detection, and communicates the high-pressure cavity with the low-pressure cavity when the first pressure detection unit and the second pressure detection unit do not perform air pressure detection; separate transmission of liquid and gas is carried out through a liquid flow channel composed of an upstream hydraulic channel and a downstream hydraulic channel and a gas pressure cavity channel, so that a high-pressure cavity extends between a first pressure detection unit and the upstream hydraulic channel, a low-pressure cavity extends between a second pressure detection unit and the downstream hydraulic channel, and a medium is introduced at the beginning or discharged after completion; and the damage of measurement components caused by overlarge one-way pressure difference is avoided.

Description

Technical Field

[0001] This invention belongs to the field of transmitter technology, and specifically relates to a differential pressure transmitter. Background Technology

[0002] A transmitter is a sensor that outputs a standard signal. It operates based on the principle of negative feedback and mainly consists of a measuring section, an amplifier, and a feedback section. It is a commonly used detection device in process control. Based on its pressure-to-signal conversion method, it can be classified into: resistance strain gauge pressure transmitters, diffused silicon pressure transmitters, ceramic pressure transmitters, etc. Among these, pressure transmitters that display the pressure reading based on capacitance changes are also called differential pressure transmitters.

[0003] Chinese patent application CN109900415A discloses a differential pressure transmitter, including a base and a positive pressure isolation diaphragm. A spike pulse filtering device is provided on the end face of the base, inside the positive pressure isolation diaphragm. The spike pulse filtering device includes a buffer groove, a sealing piston, a buffer spring, a positioning rod, and a pressure-bearing component. The positioning rod, under the pressure of the buffer spring, holds the sealing piston in place within the buffer groove. This invention, by incorporating a spike pulse filtering device within the high-pressure chamber of the base and setting the initial pressure state of the buffer spring to the displacement limit of the positive pressure isolation diaphragm when it reaches the calibrated pressure value, allows pressure exceeding a threshold value to preferentially pass through the positive pressure isolation diaphragm and act on the pressure-bearing component, causing the sealing piston to compress the buffer spring. Pressure displacement exceeding the threshold is buffered by silicone oil entering the buffer groove, effectively protecting the central pressure-sensing diaphragm and related capacitors from spike pulse effects.

[0004] The sensing components of the aforementioned differential pressure transmitter are very fragile. When gas is introduced into the high-pressure or low-pressure side in one direction, a huge pressure difference will be formed, causing damage to the components, resulting in the loss of measurement accuracy of the measuring device and rendering it unusable. Summary of the Invention

[0005] The purpose of this invention is to provide a differential pressure transmitter to solve the problem that in the prior art, when gas is introduced into the differential pressure transmitter in one direction at the high or low pressure end, the huge pressure difference can easily cause damage to the components.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The present invention provides a differential pressure transmitter, including a hydraulic body, wherein the hydraulic body is provided with an upstream hydraulic channel and a downstream hydraulic channel, the upstream hydraulic channel and the downstream hydraulic channel are connected, and a valve body mechanism for controlling the on and off is installed at the connection between the upstream hydraulic channel and the downstream hydraulic channel.

[0008] Below the upstream hydraulic channel, there is a pneumatic chamber that communicates with the downstream hydraulic channel. An overload membrane is installed inside the pneumatic chamber, which divides the pneumatic chamber into a high-pressure chamber and a low-pressure chamber. A movable sealing mechanism is installed inside the low-pressure chamber.

[0009] A first pressure detection unit is installed in the upstream hydraulic channel, and a second pressure detection unit is installed in the downstream hydraulic channel. The sealing mechanism isolates the high-pressure chamber from the low-pressure chamber when the first and second pressure detection units perform air pressure detection, and connects the high-pressure chamber from the low-pressure chamber when the first and second pressure detection units do not perform air pressure detection.

[0010] Optionally, the upstream hydraulic channel includes an upstream cavity and an upstream hole that is laterally opened and communicates with the upstream cavity; the downstream hydraulic channel includes a downstream cavity that is disposed opposite to the upstream cavity and a downstream hole that is laterally opened and communicates with the downstream cavity; the downstream hole is located below the upstream hole and intersects with the upstream hole; a communication hole for installing the valve body mechanism is provided at the intersection of the upstream hole and the downstream hole.

[0011] The upstream cavity is connected to a liquid inlet mechanism, and the downstream cavity is connected to a liquid outlet mechanism.

[0012] Optionally, a raised bed is installed in the low-pressure chamber, and the overload membrane is pre-tensioned on the raised bed so that the overload membrane cannot be deflected into the high-pressure chamber.

[0013] Optionally, the high-pressure chamber is located on the inner wall of the upstream hole, and a first diaphragm is provided on the inner wall of the upstream hole to isolate the high-pressure chamber; the low-pressure chamber is located on the inner wall of the downstream hole, and a second diaphragm is provided on the inner wall of the downstream hole to isolate the low-pressure chamber.

[0014] Both the first diaphragm sheet and the second diaphragm sheet include a diaphragm sealing body and a diaphragm bed. The diaphragm sealing body is installed on the diaphragm bed, and a separation membrane acts above the diaphragm bed. The separation membrane is fixed on the diaphragm bed by measuring pressure.

[0015] Optionally, a through hole connects the high-pressure chamber and the low-pressure chamber, and the sealing mechanism is installed inside the through hole. Both the high-pressure chamber and the low-pressure chamber are composed of two connected crescent-shaped cavities, and a detection chamber connects the two connected crescent-shaped cavities. The first pressure detection unit is installed in the detection chamber of the high-pressure chamber, and the second pressure detection unit is installed in the detection chamber of the low-pressure chamber.

[0016] An air intake mechanism and an exhaust mechanism are provided on one side of the air pressure chamber, and the air intake mechanism and the exhaust mechanism are located on one side of the through hole.

[0017] Optionally, the through hole includes a mounting portion and two parallel connecting portions, both of which are connected to the mounting portion. The overload membrane is located inside one of the connecting portions, and the sealing mechanism is installed inside the mounting portion and located at the connection between the other connecting portion and the mounting portion.

[0018] Optionally, the sealing mechanism includes a rubber ball and a rigid air supply pipe, the air supply pipe being inserted into one side of the mounting part, one end of the air supply pipe being connected to a first air inlet pipe, and one end of the first air inlet pipe being connected to an air pump and an air outlet pipe with an air valve.

[0019] Optionally, the first pressure detection unit includes a first pressure sensor, the sensing end of which is connected to the high-pressure chamber, and the second pressure detection unit includes a second pressure sensor, the sensing end of which is connected to the low-pressure chamber.

[0020] Optionally, the upper end of the valve body mechanism passes through the upper wall of the hydraulic body and is connected to a control box, and the lower surface of the control box is connected to the outer wall of the hydraulic body by a connecting rod;

[0021] The valve body mechanism includes a valve core rod and a conical valve disc fixed to the lower end of the valve core rod. The diameter of the top end of the conical valve disc is the same as the diameter of the communicating hole. A sleeve rod is slidably sleeved on the upper end of the valve core rod. The sleeve rod is inserted and fixed to the upper end of the hydraulic body. The upper end of the sleeve rod is rotatably fitted into the lower end of the connecting rod. A drive mechanism for controlling the upward or downward movement of the valve core rod is installed through the sleeve rod and the connecting rod at the upper end of the valve core rod. The drive mechanism is installed in the control box and is electrically connected to the controller.

[0022] Optionally, a programmable controller is installed inside the control box, and a pressure display screen is installed on one side of the control box. The first pressure detection unit and the second pressure detection unit are connected to the controller via a wiring harness.

[0023] The beneficial effects of this invention are:

[0024] 1. This invention utilizes the cooperation of a pressure chamber and a sealing mechanism. When the first and second pressure detection units perform air pressure detection, the sealing mechanism isolates the high-pressure chamber from the low-pressure chamber. When the first and second pressure detection units are not performing air pressure detection, the sealing mechanism connects the high-pressure chamber and the low-pressure chamber. The liquid flow channel, composed of an upstream hydraulic channel and a downstream hydraulic channel, separates the transmission of liquid and gas from the air pressure chamber. This allows the high-pressure chamber to extend between the first pressure detection unit and the upstream hydraulic channel, and the low-pressure chamber to extend between the second pressure detection unit and the downstream hydraulic channel. The medium is discharged at the beginning or after it is introduced, avoiding damage to the measuring components caused by excessive unidirectional pressure difference.

[0025] 2. The present invention uses a first pressure detection unit and a second pressure detection unit to detect the pressure in the upstream hydraulic channel and the downstream hydraulic channel respectively, and transmits the detected pressure values ​​to the controller. The controller controls and adjusts the pressure in the upstream hydraulic channel and the downstream hydraulic channel respectively to achieve pressure balance between the high pressure chamber and the low pressure chamber, thereby reducing the damage to components caused by large pressure difference between the upstream hydraulic channel and the downstream hydraulic channel. Attached Figure Description

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of the overall structure of the differential pressure transmitter provided in an embodiment of the present invention;

[0028] Figure 2 This is a bottom view of the differential pressure transmitter provided in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the internal structure of the differential pressure transmitter provided in an embodiment of the present invention;

[0030] Figure 4 This is a cross-sectional structural diagram of the differential pressure transmitter provided in an embodiment of the present invention;

[0031] Figure 5 for Figure 4 Enlarged diagram of A in the middle;

[0032] Figure 6 for Figure 4 Enlarged diagram of B in the middle;

[0033] Figure 7 This is a schematic diagram of the cross-sectional structure of the through hole located at the sealing mechanism according to an embodiment of the present invention;

[0034] Figure 8 This is a system block diagram for monitoring by a first pressure sensor and a second pressure sensor, provided for an embodiment of the present invention.

[0035] In the diagram: 1. Control box; 2. Pressure display screen; 3. Connecting rod; 4. Hydraulic body; 5. Feed connector; 6. Discharge connector; 7. First air inlet pipe; 8. Second air inlet pipe; 9. Explosion-proof pin; 10. Upstream cavity; 11. Upstream hole; 12. Wiring harness; 13. Valve body mechanism; 131. Sleeve rod; 132. Conical valve disc; 133. Valve core rod; 14. Downstream cavity; 15. Downstream hole; 16. Sealing mechanism; 161. Rubber ball; 162. Air supply pipe; 17. First pressure sensor; 18. Protruding bed; 19. First diaphragm; 20. Second diaphragm; 21. Mounting part; 22. Connecting part; 23. Pressure chamber; 24. Detection chamber; 25. Second pressure sensor; 26. Overload diaphragm. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0037] This invention provides a differential pressure transmitter, such as... Figure 1-8 As shown, the system includes a hydraulic body 4, which has an upstream hydraulic channel and a downstream hydraulic channel inside. One end of the upstream hydraulic channel is connected to one end of the downstream hydraulic channel, and a valve body mechanism 13 is installed at the junction of the upstream and downstream hydraulic channels. The upper end of the valve body mechanism 13 passes through the upper wall of the hydraulic body 4 and is connected to a control box 1, and the lower surface of the control box 1 is connected to the outer wall of the hydraulic body 4 by a connecting rod 3. The other end of the upstream hydraulic channel is connected to an inlet mechanism, and the other end of the downstream hydraulic channel is connected to an outlet mechanism. Through the cooperation of the inlet and outlet mechanisms, liquid flows from the upstream hydraulic channel to the downstream hydraulic channel and is discharged through the outlet mechanism. The valve body mechanism 13 is used to control the flow of liquid from the upstream hydraulic channel into the downstream hydraulic channel.

[0038] like Figure 3 As shown, the upstream hydraulic channel includes an upstream cavity 10 and an upstream hole 11 that is laterally opened and connects to the upstream cavity 10, i.e., the upstream cavity 10 and the upstream hole 11 form a first T-shaped structure. The downstream hydraulic channel includes a downstream cavity 14 that is opposite to the upstream cavity 10 and a downstream hole 15 that is laterally opened and connects to the downstream cavity 14, i.e., the first T-shaped structure and the second T-shaped structure are located at the two ends of the hydraulic body 4, and the downstream cavity 14 and the downstream hole 15 form a second T-shaped structure. The downstream hole 15 is located below the upstream hole 11 and intersects with the upstream hole 11, i.e., the upstream hole 11 and the downstream hole 15 are staggered. A connecting hole for the installation of the valve body mechanism 13 is provided at the junction of the upstream hole 11 and the downstream hole 15. By adjusting the valve body mechanism 13, the upstream hole 11 and the downstream hole 15 can be connected or isolated to realize the flow and disconnection of the liquid.

[0039] like Figure 1As shown, specifically, an inlet mechanism is connected to the upstream cavity 10, and an outlet mechanism is connected to the downstream cavity 14. The inlet mechanism includes at least one feed connector 5 with an internally threaded hole in its inner wall, and a feed control valve is installed on the feed connector 5. The feed connector 5 is connected to one side of the upstream cavity 10, facilitating connection to the delivery pipe of the liquid to be transferred, allowing the liquid to enter the upstream hydraulic channel. The outlet mechanism includes at least one outlet connector 6 with an internally threaded inner wall, installed on one side of the downstream cavity 14, and the outlet connector 6 and the feed connector 5 are located on the same side of the hydraulic body 4. The internal thread of the outlet connector 6 facilitates connection to the liquid receiving equipment, improving the convenience of liquid transfer.

[0040] like Figures 4-7 As shown, the hydraulic body 4 is located below the upstream hydraulic channel and has a pneumatic chamber communicating with the downstream hydraulic channel. An overload membrane 26 is installed inside the pneumatic chamber, dividing it into a high-pressure chamber and a low-pressure chamber 23. The high-pressure chamber is located on the inner wall of the upstream hole 11, and a first diaphragm 19 is provided on the inner wall of the upstream hole 11 to isolate the high-pressure chamber. The low-pressure chamber 23 is located on the inner wall of the downstream hole 15, and a second diaphragm 20 is provided on the inner wall of the downstream hole 15 to isolate the low-pressure chamber 23. A movable sealing mechanism 16 is installed inside the low-pressure chamber 23. When the first and second pressure detection units perform pneumatic pressure detection, the sealing mechanism 16 isolates the high-pressure chamber from the low-pressure chamber 23; when the first and second pressure detection units do not perform pneumatic pressure detection, the sealing mechanism 16 connects the high-pressure chamber and the low-pressure chamber 23. An air intake mechanism and an exhaust mechanism are provided on one side of the pneumatic chamber. The liquid and gas are separately transmitted through the liquid flow channel composed of the upstream hydraulic channel and the downstream hydraulic channel. This allows the high-pressure chamber to extend between the first pressure detection unit and the upstream hydraulic channel, and the low-pressure chamber 23 to extend between the second pressure detection unit and the downstream hydraulic channel. The medium is discharged at the beginning or after the medium is introduced, thus avoiding damage to the measuring components caused by excessive unidirectional pressure difference.

[0041] A through-hole connects the high-pressure chamber and the low-pressure chamber 23, and a sealing mechanism 16 is installed inside the through-hole. Both the high-pressure chamber and the low-pressure chamber 23 consist of two interconnected crescent-shaped cavities, with a detection chamber 24 connecting them. A first pressure detection unit is installed in the detection chamber 24 within the high-pressure chamber, and a second pressure detection unit is installed in the detection chamber 24 within the low-pressure chamber 23. An intake mechanism and an exhaust mechanism are located on one side of the through-hole. The first and second pressure detection units sense the pressure within the high-pressure chamber and the low-pressure chamber 23, respectively. Before pressure measurement, when high-pressure or low-pressure gas is introduced through the intake mechanism, the through-hole is in a connected state; during pressure measurement, the through-hole is in a sealed state; after measurement, the through-hole connects both ends, and then the high-pressure or low-pressure gas is discharged through the exhaust mechanism.

[0042] like Figure 5 As shown, the through-hole includes a mounting portion 21 and two parallel connecting portions 22, both of which are connected to the mounting portion 21. An overload membrane 26 is located inside one of the connecting portions 22, dividing the pressure chamber into a high-pressure chamber and a low-pressure chamber. A sealing mechanism 16 is installed inside the mounting portion 21 and located at the connection between the other connecting portion 22 and the mounting portion 21. The movable arrangement of the sealing mechanism 16 facilitates connecting the high-pressure chamber and the low-pressure chamber before and after testing, and separating the high-pressure chamber and the low-pressure chamber during testing.

[0043] The sealing mechanism 16 includes a rubber ball 161 and a rigid air supply pipe 162, which is inserted into one side of the mounting part 21. One end of the air supply pipe 162 is connected to a first air inlet pipe 7, and the other end of the first air inlet pipe 7 is connected to an air pump and an air outlet pipe with an air valve. During air pressure testing, an air source is provided by the air pump, and the air source enters the interior of the rubber ball 161 through the air supply pipe 162. The incoming gas increases the volume of the rubber ball 161, causing it to block the connecting part 22, thus separating the high-pressure chamber from the low-pressure chamber 23. After the air pressure test is completed, the air pump stops working, the air valve on the air outlet pipe is opened, and the volume of the rubber ball 161 shrinks, exposing the connecting part 22, which facilitates the connection between the high-pressure chamber and the low-pressure chamber 23.

[0044] Looking back Figure 5 As shown, a convex bed 18 is installed in the low-pressure chamber 23, and the overload membrane 26 is pre-tensioned on the convex bed 18 so that the overload membrane 26 cannot be deflected into the high-pressure chamber. This facilitates a certain high-pressure extension space for the high-pressure chamber and reduces the probability of excessive pressure difference between the high-pressure chamber and the low-pressure chamber 23.

[0045] Both the first diaphragm piece 19 and the second diaphragm piece 20 include a diaphragm seal and a diaphragm bed, with the diaphragm seal mounted on the diaphragm bed. A separation membrane acts above the diaphragm bed, and the separation membrane is fixed to the diaphragm bed by measuring pressure. The separation membrane forms a pressure chamber between the upstream hole 11 and the downstream hole 15, which is connected to the upstream hydraulic channel and the downstream hydraulic channel, allowing pressure to be applied to the detection chamber 24.

[0046] like Figure 7 As shown, the first pressure detection unit includes a first pressure sensor 17, the sensing end of which is connected to the high-pressure chamber. The second pressure detection unit includes a second pressure sensor 25, the sensing end of which is connected to the low-pressure chamber 23. The pressure in the high-pressure chamber and the low-pressure chamber 23 is sensed by the first pressure sensor 17 and the second pressure sensor 25.

[0047] Looking back Figure 4As shown, the valve body mechanism 13 includes a valve core rod and a conical valve disc 132 fixed to the lower end of the valve core rod. The diameter of the top end of the conical valve disc 132 is the same as the diameter of the connecting hole. A sleeve rod 131 is slidably sleeved on the upper end of the valve core rod. The sleeve rod 131 is inserted and fixed to the upper end of the hydraulic body 4, and the upper end of the sleeve rod 131 is rotatably fitted into the lower end of the connecting rod 3. A drive mechanism for controlling the upward or downward movement of the valve core rod 133 is installed on the upper end of the valve core rod 133 through the sleeve rod 131 and the connecting rod 3. The drive mechanism is installed inside the control box 1. The drive mechanism is electrically connected to the controller. The drive mechanism is equipped with a cylinder or a drive motor. If it is a cylinder, the upper end of the valve core rod 133 is connected to the piston rod end of the cylinder. The cylinder drives the valve core rod 133 to move vertically, thereby moving the valve core rod 133 up or down. If it is a drive motor, the upper end of the valve core rod 133 is threaded to the lower side wall of the control box 1, and a rack is fixed to the upper end of the valve core rod 133. The drive motor is installed inside the control box 1, and a gear is installed on the output shaft of the drive motor. The gear meshes with the rack. The drive motor drives the gear to rotate, causing the gear to drive the rack to move up or down. The rack drives the valve core rod 133 to move up or down, thereby adjusting the position of the conical valve disc 132.

[0048] Combination Figure 8 As shown, a programmable controller is installed inside the control box 1. A pressure display screen 2 is installed on one side of the control box 1. A first pressure detection unit and a second pressure detection unit are also installed inside the hydraulic body 4. The first and second pressure detection units are connected to the upstream and downstream hydraulic channels, respectively. The first and second pressure detection units are connected to the controller via a wiring harness 12. The first and second pressure detection units detect the pressure in the upstream and downstream hydraulic channels, respectively, and transmit the detected pressure values ​​to the controller. The controller then controls and adjusts the pressure in the upstream and downstream hydraulic channels to achieve pressure balance between the high-pressure chamber and the low-pressure chamber 23, reducing component damage caused by large pressure differences between the upstream and downstream hydraulic channels.

[0049] One end of the controller is connected to a wireless communication module, and the other end of the wireless communication module is electrically connected to a remote control system. The remote control system is set up as a complete control system connected to the differential pressure transmitter according to the installation requirements. The wireless communication module is used to realize remote control of the controller, thereby improving the convenience of controlling the differential pressure transmitter.

[0050] As described above, more preferably, the air intake mechanism includes a second air intake pipe 8 with an air valve. The second air intake pipe 8 is connected to one side of the mounting part 21, and the first air intake pipe 7, the second air intake pipe 8, and the exhaust pipe are arranged side by side. One end of the second air intake pipe 8 is connected to a gas compressor through a first air pipe, and the outlet end of the gas compressor is connected to a booster pump through the second air pipe. One end of the booster pump is connected to one end of the second air pipe, and both the first and second air pipes are equipped with air valves. When low-pressure gas is introduced, the air valve on the first air pipe is opened, allowing the low-pressure gas generated by the gas compressor to enter the pneumatic chamber through the second air intake pipe 8. When high-pressure gas is introduced, the air valve on the second air pipe is opened, allowing the low-pressure gas generated by the gas compressor to be boosted by the booster pump. The boosted high-pressure gas then enters the interior of the second air intake pipe 8 through the second air pipe, and then enters the pneumatic chamber through the second air intake pipe 8.

[0051] The exhaust mechanism includes an exhaust pipe with a valve. One end of the exhaust pipe is connected to the mounting part 21, and the other end of the exhaust pipe is connected to a gas recovery device. When the gas in the pneumatic chamber is exhausted, the valve on the exhaust pipe is opened to facilitate the discharge of the gas in the pneumatic chamber, and the discharged gas is recovered and reused using the gas recovery device.

[0052] An explosion-proof pin 9 is also installed at the lower end of the hydraulic body 4, and two bolts are provided on one side of the explosion-proof pin 9. The bolts are threadedly connected to the lower end of the hydraulic body 4. When the pressure in the pneumatic chamber is too high, the explosion-proof pin 9 can be removed to release the air pressure in the pneumatic chamber, thereby reducing the pressure in the pneumatic chamber, avoiding excessive pressure in the pneumatic chamber, and improving the safety of use.

[0053] Before liquid transfer, gas is introduced into the pneumatic chamber through the second air inlet pipe 8 according to the liquid transfer requirements. At this time, the sealing mechanism 16 exposes the connecting part 22, and the high pressure chamber is connected to the low pressure chamber 23 to protect the first pressure sensor 17 and the second pressure sensor 25, prevent the sensors from being suddenly attacked by the pressure generated by the liquid flow, and improve the sensor sensing accuracy.

[0054] During liquid transfer, the liquid enters the upstream chamber 10 through the inlet connector 5, then enters the upstream hole 11 through the upstream chamber 10. The drive mechanism moves the valve core rod 133 upwards, causing the liquid to enter the downstream hole 15 through the upstream hole 11, then the downstream chamber 14 through the downstream hole 15, and finally flows out through the outlet connector 6. Since the high-pressure chamber of the pneumatic channel is located at the upstream hydraulic channel, and the low-pressure chamber 23 is located at the downstream hydraulic channel, the sealing mechanism 16 seals the connecting part 22 during liquid transfer, making the high-pressure chamber and low-pressure chamber 23 two independent chambers. The pressure inside the high-pressure chamber is sensed and measured by the first pressure sensor 17. Because the high-pressure chamber is connected to the upstream hydraulic channel by the first diaphragm 19, the liquid flow impacts the first diaphragm 19, causing it to deform and generate negative pressure inside the high-pressure chamber. The first pressure sensor 17 detects the pressure inside the high-pressure chamber and displays it via a pressure display. Screen 2 shows that if the pressure in the high-pressure chamber does not meet the requirements for liquid ultra-high pressure differential transmission, high-pressure gas is introduced into the high-pressure chamber through the second air inlet pipe 8. The high-pressure gas pushes the first diaphragm 19 to increase the pressure on the upstream hydraulic channel, so that it meets the requirements for liquid ultra-high pressure differential transmission. The second pressure sensor 25 senses the pressure in the low-pressure chamber 23 and uses the pressure in the low-pressure chamber 23 to detect the pressure in the downstream hydraulic channel, and transmits the sensed pressure value to the controller. When the load-bearing capacity of the overload diaphragm 26 is about to reach its limit, the controller controls the air valve on the air outlet pipe to release a certain proportion of air from the rubber ball 161, exposing the part of the connecting part 22 that does not contain the overload diaphragm 26, so that the high-pressure chamber and the low-pressure chamber 23 are connected to balance the pressure in the high-pressure chamber and the low-pressure chamber 23. After the liquid transmission is completed, the air valve on the exhaust pipe is opened to discharge the gas in the pneumatic chamber from the exhaust pipe.

[0055] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of the present invention.

Claims

1. A differential pressure transmitter, characterized in that: Includes a hydraulic body (4), the hydraulic body (4) is provided with an upstream hydraulic channel and a downstream hydraulic channel inside, the upstream hydraulic channel and the downstream hydraulic channel are connected, and a valve body mechanism (13) for controlling the on and off is installed at the connection between the upstream hydraulic channel and the downstream hydraulic channel; Below the upstream hydraulic channel is a pneumatic chamber that communicates with the downstream hydraulic channel. An overload membrane (26) is installed inside the pneumatic chamber. The overload membrane (26) divides the pneumatic chamber into a high-pressure chamber and a low-pressure chamber (23). A movable sealing mechanism (16) is installed inside the low-pressure chamber (23). The upstream hydraulic channel is equipped with a first pressure detection unit, and the downstream hydraulic channel is equipped with a second pressure detection unit. The sealing mechanism (16) isolates the high-pressure chamber from the low-pressure chamber (23) when the first pressure detection unit and the second pressure detection unit perform air pressure detection, and the sealing mechanism (16) connects the high-pressure chamber from the low-pressure chamber (23) when the first pressure detection unit and the second pressure detection unit do not perform air pressure detection.

2. The differential pressure transmitter according to claim 1, characterized in that: The upstream hydraulic channel includes an upstream cavity (10) and an upstream hole (11) that is laterally opened and connected to the upstream cavity (10). The downstream hydraulic channel includes a downstream cavity (14) that is opposite to the upstream cavity (10) and a downstream hole (15) that is laterally opened and connected to the downstream cavity (14). The downstream hole (15) is located below the upstream hole (11) and intersects with the upstream hole (11). A connecting hole for installing the valve body mechanism (13) is provided at the junction of the upstream hole (11) and the downstream hole (15). The upstream cavity (10) is connected to a liquid inlet mechanism, and the downstream cavity (14) is connected to a liquid outlet mechanism.

3. A differential pressure transmitter according to claim 1 or 2, characterized in that: A convex bed (18) is installed in the low-pressure chamber, and the overload membrane (26) is pre-tensioned on the convex bed (18) so that the overload membrane (26) cannot be deflected into the high-pressure chamber.

4. A differential pressure transmitter according to claim 2, characterized in that: The high-pressure chamber is located on the inner wall of the upstream hole (11), and a first diaphragm (19) is provided on the inner wall of the upstream hole (11) to isolate the high-pressure chamber. The low-pressure chamber (23) is located on the inner wall of the downstream hole (15), and a second diaphragm (20) is provided on the inner wall of the downstream hole (15) to isolate the low-pressure chamber (23). Both the first diaphragm sheet (19) and the second diaphragm sheet (20) include a diaphragm seal and a diaphragm bed. The diaphragm seal is mounted on the diaphragm bed, and a separation membrane acts above the diaphragm bed. The separation membrane is fixed on the diaphragm bed by measuring pressure.

5. A differential pressure transmitter according to claim 1, characterized in that: A through hole connects the high-pressure chamber and the low-pressure chamber (23), and the sealing mechanism (16) is installed inside the through hole. The high-pressure chamber and the low-pressure chamber (23) are both composed of two connected crescent-shaped cavities, and a detection chamber (24) connects the two connected crescent-shaped cavities. The first pressure detection unit is installed in the detection chamber (24) inside the high-pressure chamber, and the second pressure detection unit is installed in the detection chamber (24) inside the low-pressure chamber (23). An air intake mechanism and an exhaust mechanism are provided on one side of the air pressure chamber, and the air intake mechanism and the exhaust mechanism are located on one side of the through hole.

6. A differential pressure transmitter according to claim 5, characterized in that: The through hole includes a mounting portion (21) and two parallel connecting portions (22), both of which are connected to the mounting portion (21). The overload membrane (26) is located inside one of the connecting portions (22). The sealing mechanism (16) is installed inside the mounting portion (21) and is located at the connection between the other connecting portion (22) and the mounting portion (21).

7. A differential pressure transmitter according to claim 6, characterized in that: The sealing mechanism (16) includes a rubber ball (161) and a rigid air supply pipe (162). The air supply pipe (162) is inserted into one side of the mounting part (21). One end of the air supply pipe (162) is connected to a first air inlet pipe (7). One end of the first air inlet pipe (7) is connected to an air pump and an air outlet pipe with an air valve.

8. A differential pressure transmitter according to claim 1, characterized in that: The first pressure detection unit includes a first pressure sensor (17), the sensing end of the first pressure sensor (17) is connected to the high pressure chamber, and the second pressure detection unit includes a second pressure sensor (25), the sensing end of the second pressure sensor (25) is connected to the low pressure chamber.

9. A differential pressure transmitter according to claim 1, characterized in that: The upper end of the valve body mechanism (13) passes through the upper wall of the hydraulic body (4) and is connected to the control box (1). The lower surface of the control box (1) is connected to the outer wall of the hydraulic body (4) by a connecting rod (3). The valve body mechanism (13) includes a valve core rod (133) and a conical valve disc (132) fixed at the lower end of the valve core rod (133). The top diameter of the conical valve disc (132) is the same as the diameter of the connecting hole. A sleeve rod (131) is slidably sleeved on the upper end of the valve core rod (133). The sleeve rod (131) is inserted and fixed on the upper end of the hydraulic body (4). The upper end of the sleeve rod (131) is rotatably fitted into the lower end of the connecting rod (3). The upper end of the valve core rod (133) passes through the sleeve rod (131) and the connecting rod (3) and is equipped with a drive mechanism that controls the valve core rod (133) to move up or down. The drive mechanism is installed in the control box (1) and is electrically connected to the controller.

10. A differential pressure transmitter according to claim 9, characterized in that: The control box (1) is equipped with a programmable controller. A pressure display screen (2) is installed on one side of the control box (1). The first pressure detection unit and the second pressure detection unit are connected to the controller via a wiring harness (12).

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