Double-flange liquid level meter

Abstract

The utility model provides a double-flange liquid level meter, and particularly relates to the technical field of liquid level measurement. The double-flange liquid level meter comprises a transmitter, a first flange plate and a second flange plate, wherein the first flange plate is communicated with the transmitter through a first capillary tube; the second flange plate is communicated with the transmitter through a second capillary tube; wherein diaphragms are arranged on the sides, away from the transmitter, of the first flange plate and the second flange plate, the diaphragms comprise stainless steel diaphragms and polytetrafluoroethylene diaphragms, and the stainless steel diaphragms are coated with the polytetrafluoroethylene diaphragms. The liquid level meter can solve the problems that a tantalum diaphragm is prone to hydrogen embrittlement and hydrogen permeation.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid level measurement, in particular to a double-flange liquid level gauge. Background Art

[0002] The esterification reaction system for methyl methacrylate (MMA) operates in a strongly acidic, water-based environment. The reactor, liquid-contacting equipment, and associated pipelines are all constructed from corrosion-resistant materials such as zirconium and tantalum. The level gauge used to measure the liquid level also utilizes a tantalum diaphragm for contact with the liquid. However, because the thickness of the transmitter diaphragm is typically only 0.04 to 0.08 mm, hydrogen embrittlement and hydrogen permeation can significantly reduce the corrosion resistance of the level gauge diaphragm, posing a potential risk to production. Summary of the Invention

[0003] In view of the above problems existing in the prior art, the utility model provides a double-flange liquid level gauge to improve the problem that the diaphragm of the double-flange liquid level gauge is prone to hydrogen embrittlement and hydrogen penetration.

[0004] To achieve the above-mentioned purpose and other related purposes, the present invention provides a double-flange liquid level gauge, which is used to detect the liquid level in the equipment. The double-flange liquid level gauge includes a transmitter, a first flange and a second flange. The first flange is connected to the transmitter through a first capillary tube; the second flange is connected to the transmitter through a second capillary tube; wherein, the first flange and the second flange are both provided with a diaphragm on the side facing away from the transmitter, and the diaphragm includes a stainless steel diaphragm and a polytetrafluoroethylene diaphragm, and the polytetrafluoroethylene diaphragm covers the stainless steel diaphragm.

[0005] In one embodiment of the present invention, the double flange liquid level gauge also includes a back-blowing system, which includes a nitrogen pipe and an air source. One end of the nitrogen pipe is connected to the air source, and the other end of the nitrogen pipe introduces nitrogen into the interior of the equipment.

[0006] In one embodiment of the present invention, the back-blowing system further includes a flushing ring, which is arranged between the pressure port of the device and the diaphragm, and the nitrogen pipe enters the device through the flushing ring.

[0007] In one embodiment of the present invention, the back-blowing system also includes a nitrogen introduction component, which includes a necked butt-weld flange and a concentric reducer. The end of the nitrogen pipe facing away from the gas source is connected to the necked butt-weld flange, one end of the concentric reducer is connected to the necked butt-weld flange, and the other end is connected to the flushing ring.

[0008] In one embodiment of the present invention, a shut-off valve is provided on the pressure taking port of the equipment, the side of the first flange plate provided with the diaphragm is connected to the shut-off valve, and the side of the second flange plate provided with the diaphragm is connected to the shut-off valve.

[0009] In one embodiment of the present invention, the flushing ring is arranged between the stop valve and the diaphragm, and the nitrogen in the nitrogen pipe enters the interior of the device from between the stop valve and the diaphragm through the stop valve.

[0010] In one embodiment of the present invention, the double-flange liquid level gauge also includes a pressure relief assembly, which includes a ball valve, a connecting pipe and a pipe cap. One end of the connecting pipe is connected to the flushing ring, and the other end is blocked by the pipe cap. The ball valve is arranged on the connecting pipe.

[0011] In an embodiment of the present invention, the pressure relief assembly further includes a reducing single-end short section, and the reducing single-end short section is arranged between the ball valve and the flushing ring.

[0012] In one embodiment of the present invention, the stainless steel diaphragm includes: a 316 stainless steel diaphragm.

[0013] In one embodiment of the present invention, the polytetrafluoroethylene diaphragm is an independent polytetrafluoroethylene diaphragm or a polytetrafluoroethylene coating sprayed on the stainless steel diaphragm.

[0014] This double-flange level gauge utilizes a stainless steel and polytetrafluoroethylene (PTFE) diaphragm, with the PTFE diaphragm completely encasing the stainless steel diaphragm. This isolates the gauge from corrosive media while preventing excessive corrosion and damage to the stainless steel diaphragm. The PTFE diaphragm itself is relatively inexpensive and easily replaceable, significantly reducing maintenance costs while maintaining effective operation.

[0015] In addition, the double-flange liquid level gauge of the present invention is also provided with a back-blowing system. While detecting the liquid level in the equipment, the back-blowing system is used to blow air to the pressure port of the equipment. On the one hand, it can reduce the concentration of organic gas at the pressure port of the instrument, protect the PTFE layer from being penetrated by the organic medium, and prevent the PTFE diaphragm from bulging; on the other hand, it can also prevent the gaseous organic matter from polymerizing at the pipe mouth and affecting the pressure measurement.

[0016] Compared with the application of insertion type liquid level gauge, installing a stop valve at the pressure taking port of the equipment can complete maintenance without stopping the device during normal operation, which improves the convenience of instrument maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a schematic structural diagram of a double-flange level gauge in one embodiment of the present invention;

[0019] Figure 2 FIG. 1 is a structural diagram of another embodiment of a double-flange liquid level gauge according to the present invention.

[0020] Component number description:

[0021] 100. Double flange level gauge; 110. Transmitter; 120. First flange; 121. First capillary; 130. Second flange; 131. Second capillary; 140. Diaphragm; 141. Stainless steel diaphragm; 142. Polytetrafluoroethylene diaphragm; 150. Backflush system; 151. Nitrogen pipe; 152. Flushing ring; 153. Neck welding flange; 154. Concentric reducer; 155. Gas source; 156. Flow meter; 160. Stop valve; 170. Pressure relief assembly; 171. Connecting pipe; 172. Pipe cap; 173. Ball valve; 174. Reducing single-end short section; 175. Single-end short section; 200. Equipment; 201. First pressure port; 202. Second pressure port. DETAILED DESCRIPTION

[0022] The following describes the implementation of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation methods. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following examples and the features in the examples can be combined with each other unless there is a conflict. It should also be understood that the terms used in the examples of the present invention are for the purpose of describing specific implementation methods, not for the purpose of limiting the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0023] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the endpoints may be used. Unless otherwise defined, all technical and scientific terms used in this utility model are consistent with the prior art as understood by those skilled in the art and the description of this utility model. Any prior art methods, equipment, and materials similar or equivalent to those in the examples of this utility model may also be used to implement this utility model.

[0024] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0025] The inventors discovered during their research that the typical damage mode of tantalum materials is hydrogen embrittlement, and there are three hydrogen embrittlement mechanisms:

[0026] 1. When tantalum is connected to cheap materials such as low-carbon steel and certain materials (especially Hastelloy B, nickel and lead) in a galvanic connection, tantalum becomes the cathode of the primary battery in some highly corrosive water-based media and hydrogen embrittlement failure occurs;

[0027] 2. Due to the presence of stray current (caused by induction of adjacent lines, leakage, variable ground voltage and other sources), tantalum becomes the cathode of the primary battery, absorbs atomic hydrogen in the electrolytic cell (primary battery) and becomes embrittled. The stray voltage may be short-lived, but the effect of the absorbed hydrogen on tantalum hydrogen embrittlement is cumulative.

[0028] 3. When pure tantalum is exposed to high-temperature corrosive acid, hydrogen embrittlement is not uniform corrosion damage. Instead, there is a tantalum hydrogen embrittlement mechanism based on stress-induced hydride precipitation.

[0029] The inventors of this application also discovered during their research that within 30 days of use, the hydrogen content in both the tantalum material insertion tube and the front corrugated diaphragm of a level gauge in a methyl methacrylate (MMA) esterification reaction system exceeded the standard. Their plasticity significantly decreased compared to the standard, and their fracture surface exhibited brittleness, consistent with hydrogen embrittlement. Analysis concluded that the leakage in the level gauge transmitter was caused by the embrittlement and breakage of the front diaphragm, which allowed sulfuric acid to enter the transmitter insertion tube, severely corroding the 316L lining and producing hydrogen gas and hydrogen atoms. Simultaneously, the sulfuric acid intrusion formed a galvanic cell between the 316L lining and the outer R05200 tantalum material, with the tantalum acting as the cathode. This caused galvanic corrosion, further triggering hydrogen embrittlement of the tantalum material in the insertion tube.

[0030] Based on this, the utility model provides a double-flange liquid level gauge, which uses a double-layer diaphragm composed of a stainless steel diaphragm and a polytetrafluoroethylene diaphragm to replace the tantalum liquid level gauge diaphragm of the methyl methacrylate esterification reaction system, which can effectively improve a series of problems caused by hydrogen embrittlement of the liquid level gauge diaphragm.

[0031] See also Figure 1 The double-flange level gauge 100 of the present invention is used to detect the liquid level in a device 200, such as a reactor. A first pressure port 201 is provided at the top of the device 200, and a second pressure port 202 is provided at the bottom of the device 200. The double-flange level gauge 100 includes a transmitter 110, a first flange 120, and a second flange 130. The first flange 120 and the second flange 130 are connected to the transmitter 110 via capillaries. For ease of description, the capillary between the first flange 120 and the transmitter 110 is referred to as the first capillary 121, and the capillary between the second flange 130 and the transmitter 110 is referred to as the second capillary 131. A diaphragm 140 is provided on both the first flange 120 and the second flange 130 on the side facing away from the transmitter 110 (the side connected to the device 200). During use, the first flange 120 is arranged on the first pressure taking port 201 of the device 200 and is connected to the cavity inside the device 200. The second flange 130 is arranged on the second pressure taking port 202 of the device 200. The pressure in the upper cavity of the device 200 can be transmitted to the transmitter 110 through the diaphragm 140 and the first capillary 121 on the first flange 120. The bottom pressure of the liquid in the device 200 can be transmitted to the transmitter 110 through the diaphragm 140 and the second capillary 131 on the second flange 130. The transmitter 110 can calculate the pressure difference based on the two received pressures. Finally, the liquid level in the device 200 can be calculated based on the pressure difference and the density of the liquid in the device 200.

[0032] See also Figure 1The diaphragm 140 in the double-flange level gauge 100 is a key component that is in direct contact with the measured medium, and the choice of its material is crucial. In this application, the diaphragm 140 includes a stainless steel diaphragm 141 and a polytetrafluoroethylene diaphragm 142, wherein the stainless steel diaphragm 141 is integrated on the flange (the first flange 120 and the second flange 130) of the level gauge, and the polytetrafluoroethylene diaphragm 142 covers the stainless steel diaphragm 141. Furthermore, the stainless steel diaphragm 141 adopts a 316L material diaphragm. 316L stainless steel contains relatively high chromium (Cr), nickel (Ni) and molybdenum (Mo) elements. The addition of these elements enables 316L stainless steel to maintain good stability in a variety of corrosive environments, and can maintain stability in a wide range of operating temperatures and pressures. It also has good processing and welding properties, and the strength and toughness of 316L stainless steel also enable it to withstand a certain working pressure without being prone to rupture or deformation. The polytetrafluoroethylene (PTFE) diaphragm 142 exhibits excellent chemical stability and is resistant to corrosion from a variety of chemicals, including strong acids, strong bases, and organic solvents. Coated on the surface of the stainless steel diaphragm 141, the PTFE diaphragm 142 isolates the stainless steel diaphragm 141 from corrosive media, preventing excessive corrosion and extending the service life of the diaphragm 140. Furthermore, the PTFE diaphragm 142 is relatively inexpensive and easy to replace, reducing maintenance costs while ensuring effective operation.

[0033] The present application does not limit the configuration of the polytetrafluoroethylene diaphragm 142 , which may be a separate diaphragm wrapped around the outer surface of the stainless steel diaphragm 141 ; or a polytetrafluoroethylene coating sprayed on the surface of the stainless steel diaphragm 141 , and so on.

[0034] See also Figure 1 and Figure 2In one embodiment, the double-flange level gauge 100 further includes a back-blowing system 150. Specifically, the double-flange level gauge 100 includes two sets of back-blowing systems 150 with identical structures, which are respectively connected to the first pressure port 201 and the second pressure port 202 of the device 200. The back-blowing system 150 can be used to fill the pressure port of the device 200 with an inert gas, such as nitrogen. On the one hand, this can reduce the concentration of organic gas at the pressure port and protect the polytetrafluoroethylene diaphragm 142 from being penetrated by the organic medium. On the other hand, it can also prevent gaseous organic matter from polymerizing at the pressure port and affecting pressure measurement. In this embodiment, the back-blowing system 150 includes a nitrogen pipe 151 and an air source 155. The air source 155 is arranged on one side of the device 200. One end of the nitrogen pipe 151 is connected to the air source 155, and the other end is connected to the pressure port (the first pressure port 201 or the second pressure port 202) of the device 200. Furthermore, a flow meter 156 is provided on one end of the nitrogen pipe 151 connected to the gas source 155. The flow meter 156 is, for example, a rotor flow meter. By adjusting the flow of the flow meter 156, the amount of nitrogen used can be adjusted, thereby controlling the amount of nitrogen added to the first flange 120 and the second flange 130 to remain consistent, thereby ensuring accurate measurement and extending the service life of the liquid level gauge.

[0035] See also Figure 1 and Figure 2 , the following description will be made by taking the back-blowing system 150 on the first pressure port 201 as an example. A flushing ring 152 is provided between the first pressure port 201 of the equipment 200 and the first flange 120, and the nitrogen pipe 151 is connected to the first pressure port 201 through the flushing ring 152. Furthermore, the back-blowing system 150 also includes a nitrogen introduction component, and the nitrogen pipe 151 delivers nitrogen into the first pressure port 201 of the equipment 200 through the nitrogen introduction component and the flushing ring 152. In this embodiment, the nitrogen introduction component includes a necked butt-weld flange 153 and a concentric reducer 154, and one end of the nitrogen pipe 151 facing away from the gas source 155 is connected to the necked butt-weld flange 153, one end of the concentric reducer 154 is connected to the necked butt-weld flange 153, and the other end is connected to the upper end of the flushing ring 152. Thus, nitrogen enters the first pressure port 201 of the equipment 200 through the nitrogen pipe 151, the neck welding flange 153, the concentric reducer 154 and the flushing ring 152. The back-blowing system 150 on the second pressure port 202 has the same structure as above.

[0036] See also Figure 2Since the double flange level gauge 100 may malfunction during use, and the maintenance fluid of the level gauge requires shutting down the device 200 or removing it from the device 200, this will affect the production process and increase maintenance costs. Therefore, the present application provides a stop valve 160 between the first flange 120 and the first pressure port 201 and between the second flange 130 and the second pressure port 202. The stop valve 160 is fixedly mounted on the pressure port of the device 200, and the first flange 120 and the second flange 130 are respectively mounted on the first pressure port 201 and the second pressure port 202 of the device 200 through the stop valve 160. When the double flange level gauge 100 malfunctions and requires maintenance, closing the stop valve 160 can isolate the liquid in the device 200 from the level gauge; after the maintenance is completed, opening the stop valve 160 again does not affect the normal use of the double flange level gauge 100 and the device 200. In this embodiment, the flushing ring 152 of the back-blowing system 150 is installed between the flange and the stop valve 160 , and the gas in the nitrogen pipe 151 enters the stop valve 160 from the flushing ring 152 and enters the interior of the equipment 200 through the stop valve 160 .

[0037] See also Figure 1 and Figure 2 Furthermore, the double flange level gauge 100 also includes a pressure relief assembly 170, through which pressure relief can be performed to release the nitrogen at the connection before maintaining the level gauge. In one embodiment, the pressure relief assembly 170 includes a connecting pipe 171, a pipe cap 172, and a ball valve 173, wherein one end of the connecting pipe 171 is connected to the lower end of the flushing ring 152, and the other end extends freely outward. The pipe cap 172 is provided at the other end of the connecting pipe 171 for sealing the connecting pipe 171, and the ball valve 173 is provided on the connecting pipe 171 for controlling the passage of the connecting pipe 171. The ball valve 173 is, for example, a butt-welded ball valve. When the level gauge is in normal use, the ball valve 173 is closed and the pipe cap 172 is tightened to prevent leakage of the medium; during maintenance, the pipe cap 172 can be removed and the butt-welded ball valve 173 can be opened to relieve pressure. The level gauge can be safely maintained only after the nitrogen is removed.

[0038] See also Figure 1 and Figure 2 In another embodiment, the pressure relief assembly 170 further includes a reducing single-ended nipple 174, which connects the flushing ring 152 to the ball valve 173. One end of the reducing single-ended nipple 174 is connected to the bottom of the flushing ring 152, and the other end is connected to the ball valve 173. One end of the connecting tube 171 is connected to the ball valve 173, and the other end is sealed by the pipe cap 172. Furthermore, a single-ended nipple 175 can be provided between the connecting tube 171 and the pipe cap 172. The single-ended nipple 175 is used to detachably connect the pipe cap 172 to the connecting tube 171, facilitating the removal and installation of the pipe cap 172.

[0039] The double-flange level gauge provided by the present invention adopts a double-layer diaphragm composed of a stainless steel diaphragm and a polytetrafluoroethylene (PTFE) diaphragm, and the polytetrafluoroethylene diaphragm completely covers the stainless steel diaphragm, which can prevent the stainless steel diaphragm from excessive corrosion and damage to the level gauge while isolating the corrosive medium. In addition, the PTFE diaphragm is relatively cheap and easy to replace, which can save a lot of maintenance costs while ensuring the use effect. The setting of the back-blowing system can reduce the concentration of organic gas at the pressure port of the instrument, protect the PTFE diaphragm from being penetrated by the organic medium, and on the other hand, prevent the gaseous organic matter from polymerizing at the pipe mouth and affecting the pressure measurement. The setting of the stop valve facilitates instrument maintenance. Therefore, the present invention effectively overcomes some practical problems in the prior art and has high utilization value and use significance.

[0040] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed in the present invention are intended to be covered by the claims of the present invention.

Claims

1. A double flange level gauge for detecting the liquid level in equipment, characterized in that: include: transmitter; a first flange, connected to the transmitter through a first capillary tube; a second flange, connected to the transmitter via a second capillary tube; Wherein, a diaphragm is provided on the side of the first flange and the second flange facing away from the transmitter. The diaphragm includes a stainless steel diaphragm and a polytetrafluoroethylene diaphragm, and the polytetrafluoroethylene diaphragm covers the stainless steel diaphragm.

2. The double flange level gauge according to claim 1, characterized in that: The double-flange liquid level gauge also includes a back-blowing system, which includes a nitrogen pipe and an air source. One end of the nitrogen pipe is connected to the air source, and the other end of the nitrogen pipe introduces nitrogen into the interior of the device.

3. The double flange level gauge according to claim 2, characterized in that: The back-blowing system further comprises a flushing ring, which is arranged between the pressure port of the device and the diaphragm, and the nitrogen pipe enters the device through the flushing ring.

4. The double flange liquid level gauge according to claim 3, characterized in that: The back-blowing system also includes a nitrogen introduction component, which includes a necked butt-weld flange and a concentric reducer. The end of the nitrogen pipe facing away from the gas source is connected to the necked butt-weld flange, one end of the concentric reducer is connected to the necked butt-weld flange, and the other end is connected to the flushing ring.

5. The double flange liquid level gauge according to claim 3 or 4, characterized in that: A stop valve is provided on the pressure port of the equipment, the first flange is provided with a side of the diaphragm connected to the stop valve, and the second flange is provided with a side of the diaphragm connected to the stop valve.

6. The double flange liquid level gauge according to claim 5, characterized in that: The flushing ring is arranged between the stop valve and the diaphragm, and the nitrogen in the nitrogen pipe enters the interior of the device from between the stop valve and the diaphragm through the stop valve.

7. The double flange level gauge according to claim 3, characterized in that: The double flange level gauge also includes a pressure relief assembly, which includes a ball valve, a connecting pipe and a pipe cap. One end of the connecting pipe is connected to the flushing ring, and the other end is blocked by the pipe cap. The ball valve is arranged on the connecting pipe.

8. The double flange liquid level gauge according to claim 7, characterized in that: The pressure relief assembly further includes a reducing single-end short section, which is arranged between the ball valve and the flushing ring.

9. The double flange liquid level gauge according to claim 1, characterized in that: The stainless steel diaphragm includes: a 316 stainless steel diaphragm.

10. The double flange liquid level gauge according to claim 1, characterized in that: The polytetrafluoroethylene diaphragm is an independent polytetrafluoroethylene diaphragm or a polytetrafluoroethylene coating sprayed on the stainless steel diaphragm.

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