Volumetric flowmeter resistant to strong acid and strong alkali

Abstract

The utility model discloses a strong acid and strong alkali resistant volumetric flowmeter which comprises a flowmeter body, a metering groove used for containing a pair of meshed metering gears is formed in the flowmeter body, an upper cover is installed at the upper end of the flowmeter body, and the inner surface of the upper cover and the metering groove jointly define a closed metering cavity. A bottom plate is installed on the bottom face of the flowmeter body, and a top cover is installed on the upper cover. According to the volumetric flow meter, the situation that a volumetric flow meter at the present stage is not suitable for hydrochloric acid, hydrofluoric acid, sodium hydroxide and other strong acid and strong alkali media is improved, the metering cavity body and the upper cover which are integrally formed are adopted, and it is guaranteed that the strong acid and strong alkali resistant volumetric flow meter can achieve the 3MPa pressure resistance capacity.

Description

Technical Field

[0001] This utility model relates to the field of flow meter technology, specifically a volumetric flow meter resistant to strong acids and alkalis. Background Technology

[0002] In industries such as chemical engineering, pharmaceuticals, and wastewater treatment, strong acid and alkali media are frequently used. When encountering such media, PTFE (polytetrafluoroethylene) metering equipment is conventionally employed. Because PTFE is inert to almost all chemical media (including strong acids, strong alkalis, and organic solvents), it can safely measure highly corrosive fluids such as concentrated sulfuric acid, hydrochloric acid, and hydrofluoric acid, avoiding the corrosion failure problems of traditional metal materials. However, due to PTFE's relatively low mechanical strength (tensile strength approximately 20-30 MPa), it is prone to plastic deformation or cold flow under high pressure or high load, leading to changes in gear clearance and affecting measurement accuracy. Furthermore, its poor wear resistance means that gear surfaces are easily worn under high-speed or high-load conditions, shortening its service life.

[0003] This necessitates regular inspections of PTFE-based volumetric flow meters, and timely replacement after prolonged use to prevent leakage at the liquid inlet due to PTFE material wear. Furthermore, since the media typically used with PTFE are often highly corrosive fluids such as strong acids and alkalis, flow meter leakage would inevitably lead to personal injury and property damage at the production site. Therefore, this invention proposes a volumetric flow meter resistant to strong acids and alkalis to solve the aforementioned problems. Utility Model Content

[0004] Technical solution

[0005] To achieve the above objectives, the present invention provides the following technical solution: a flow meter body is included, wherein a metering groove for accommodating a pair of meshing metering gears is provided inside the flow meter body, a top cover is installed on the upper end of the flow meter body, the inner surface of the top cover and the metering groove together define a closed metering cavity, a bottom plate is installed on the bottom surface of the flow meter body, and a top cover is installed on the top cover.

[0006] Preferably, the outer wall of the flow meter body is equipped with two sets of connecting pipes, with the two ends of the two sets of connecting pipes being the inlet end and the outlet end, respectively. Both the inlet end and the outlet end are flange structures, and the flow meter body is integrally formed with the connecting pipes and flange structures on both sides.

[0007] Preferably, the flow meter body and the threaded hole are both made of PTFE (polytetrafluoroethylene). The flow meter body is provided with a sealing ring groove along the outer edge of the metering groove. The flow meter body and the top cover are sealed by a sealing ring installed on the sealing ring groove.

[0008] Preferably, the flow meter body and the top cover are provided with through holes and sliding holes around the outer edge of the sealing ring groove. The outer walls of the top cover and the bottom plate are provided with threaded holes around the circumference. The number and position of the threaded holes correspond one-to-one with the through holes and sliding holes. The threaded holes on the bottom plate are threaded with screws, and the screws move in the through holes and sliding holes and extend threadedly to the threaded holes on the top cover. The bottom plate is assembled with the flow meter body, the top cover and the top cover into a whole by screws.

[0009] Preferably, both the top cover and the bottom plate are made of metal, and the top cover has a limiting groove along the outer contour edge of the top cover.

[0010] Beneficial effects

[0011] Compared with the prior art, this utility model provides a volumetric flow meter resistant to strong acids and alkalis, which has the following beneficial effects:

[0012] 1. The flow meter body adopts an integrally machined flange connection, which reduces the possibility of loosening or damage to the internal mechanism of the flow meter due to excessive pipeline vibration, thus reducing the impact on the accuracy of the measurement results.

[0013] 2. Based on the PTFE gear flow meter, a metal top and bottom plate design is adopted. The flow meter body is locked to the top cover by bolts to the metal top and bottom plates, avoiding cracking caused by the bolts directly connecting to the flow meter body during long-term use. This enhances the pressure resistance of the integrated volumetric flow meter and ensures that the above-mentioned volumetric flow meter resistant to strong acids and alkalis can withstand pressures exceeding 3MPa. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of a volumetric flow meter resistant to strong acids and alkalis proposed in this utility model.

[0015] Figure 2 for Figure 1 Structural diagram;

[0016] Figure 3 for Figure 1 Schematic diagram of the main structure of the medium flow meter;

[0017] Figure 4 for Figure 1 Schematic diagram of the structure of the middle and upper covers;

[0018] In the diagram: 1. Flow meter body; 2. Threaded hole; 3. Inlet end; 4. Outlet end; 5. Sealing ring groove; 6. Metering groove; 7. Connecting pipe; 8. Top cover; 9. Top cover; 10. Base plate; 11. Through hole; 12. Screw; 13. Sliding hole. Detailed Implementation

[0019] In this utility model, unless otherwise stated, the orientations used, such as "up" and "down", usually refer to the direction shown in the accompanying drawings, or to the vertical, perpendicular, or gravitational direction; similarly, for ease of understanding and description, "left" and "right" usually refer to the left and right shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not used to limit this utility model.

[0020] This utility model provides a technical solution for a volumetric flow meter resistant to strong acids and alkalis:

[0021] Please see Figure 1 and Figure 2 This utility model provides a volumetric flow meter resistant to strong acids and alkalis, comprising: a flow meter body 1, an upper cover 8, a base plate 10, and a top cover 9. The flow meter body 1 is a one-piece machined (cast) gear flow meter body, with a metering groove 6 inside to accommodate a pair of meshing metering gears, enabling the gear flow meter to perform volumetric fluid measurement. The upper cover 8 is installed at the upper end of the flow meter body 1, and the inner surface of the upper cover 8 and the metering groove 6 together define a closed metering cavity, allowing the aforementioned set of gears to operate in a sealed manner within the metering cavity for gear meshing. To enhance the pressure resistance of the flow meter body 1 and the upper cover 8, the volumetric flow meter also includes a base plate 10 and a top cover 9. The base plate 10 is installed at the lower end of the flow meter body 1, and the top cover 9 is installed at the upper end of the upper cover 8, forming a gear flow meter resistant to strong acids and alkalis through cooperation with the base plate 10.

[0022] Combination Figure 2 In one embodiment of this utility model, two sets of connecting pipes 7 are installed on the outer wall of the flowmeter body 1. The two ends of the two sets of connecting pipes 7 are respectively the inlet end 3 and the outlet end 4. Both the inlet end 3 and the outlet end 4 are flange structures. The flowmeter body 1 is integrally formed with the connecting pipes 7 and the flange structures on both sides, thereby realizing the tensile and pressure resistance of the gear flowmeter. The flanges of the inlet end 3 and the outlet end 4 of the flowmeter body 1 adopt a communication structure design that is interconnected with the metering chamber 6, so that the gear flowmeter of this utility model, which is resistant to strong acids and alkalis, enters the metering chamber composed of the flowmeter body 1 and the upper cover 8 through the above-mentioned communication structure and completes the fluid metering.

[0023] In one embodiment of this utility model, the aforementioned gear flow meter resistant to strong acids and alkalis is typically used in chemical, pharmaceutical, and laboratory environments. Users often encounter highly corrosive media such as hydrofluoric acid and sodium hydroxide, making conventional materials like aluminum alloys and stainless steel unsuitable. Polytetrafluoroethylene (PTFE), however, exhibits extremely high resistance to almost all chemicals, including acids, alkalis, solvents, oxidants, and reducing agents, reacting only with certain chemicals under extreme conditions. It can be used in a temperature range of -180°C to 260°C, and can withstand even higher temperatures for short periods. It maintains excellent mechanical properties over a wide temperature range of -196°C to 260°C and does not become brittle at low temperatures. Furthermore, it possesses a low coefficient of friction, making it an ideal material for reducing friction and self-lubrication. Its coefficient of friction is extremely low, only 1 / 5 that of polyethylene, the lowest among existing plastic materials and even all engineering materials. Therefore, the contact surfaces at customer sites are typically made of PTFE, which is suitable for the aforementioned environments; that is, the flow meter body 1 and the top cover 8 are made of PTFE.

[0024] Combination Figure 2 and Figure 4 In one embodiment of this utility model, the flow meter body 1 is provided with a sealing ring groove 5 along the outer edge of the metering groove 6. To ensure the airtightness of the liquid contact surface, the sealing ring installed on the sealing ring groove 5 is usually made of PTFE material. The flow meter body 1 and the upper cover 8 cooperate through the sealing ring installed on the sealing ring groove 5 to achieve the sealing of the metering cavity. Through the above operation, the airtightness of the aforementioned gear flow meter resistant to strong acids and alkalis can be well guaranteed. Meanwhile, the flow meter body 1 and the top cover 8 are provided with through holes 11 and sliding holes 13 along the outer circumference of the sealing ring groove 5. The top cover 9 and the bottom plate 10 are provided with threaded holes 2 on their outer circumference. The number and position of the threaded holes 2 correspond one-to-one with the through holes 11 and sliding holes 13. The threaded holes 2 at the bottom plate 10 are connected to screws 12, and the screws 12 move in the through holes 11 and sliding holes 13 and extend to the threaded holes 2 at the top cover 9. The bottom plate 10 is combined with the flow meter body 1, the top cover 8 and the top cover 9 into a whole by screws 12.

[0025] Combination Figure 2 and Figure 3In one embodiment of this utility model, the top cover 9 is provided with a limiting groove along the outer contour edge of the upper cover 8, and the gap between the inner contour of the limiting groove and the outer contour of the upper cover 8 is not less than 0.1 mm. Through the above design, it can be ensured that the top cover 9 can effectively limit the upper cover 8 to the upper side of the flow meter body 1, and achieve an effective barrier between the sealing material and the contact surface through the action of external mechanical force, thereby preventing medium leakage. Its core lies in achieving sealing through the synergistic effect of pre-tightening force, elastic deformation and contact pressure. In its initial state, external pre-tightening force (such as bolt tightening) is applied to compress the sealing material (such as gasket, O-ring), causing it to produce elastic or plastic deformation, filling the microscopic unevenness of the sealing surface. The magnitude of the pre-tightening stress (initial sealing specific pressure) directly affects the sealing effect, and usually needs to exceed the medium pressure to form an initial sealing barrier. At the same time, the inherent characteristics of PTFE ensure that elastic strain energy is stored during the pre-tightening process. When the medium pressure is applied, this part of the energy can compensate for the separation of the sealing surface or stress relaxation, and maintain the contact pressure through elastic strain energy to achieve self-reinforcing sealing (self-sealing effect). Meanwhile, the effectiveness of the seal depends on the normal pressure (contact pressure) generated between the contact surfaces. According to the principles of hydrostatics, when the contact pressure is greater than the pressure difference of the medium, the medium's permeation resistance increases, and the leakage path is blocked. Under long-term operating conditions, the preload of the sealing material (PTFE) will decrease due to creep, thermal expansion, or medium corrosion (stress relaxation). At this time, the release of elastic strain energy becomes the key to maintaining the seal. PTFE's inherent combination of elasticity (filling gaps) and rigidity (resisting medium intrusion) allows the aforementioned volumetric flowmeter resistant to strong acids and alkalis to form a dynamically balanced sealing state under the drive of preload. Through its material elasticity, contact pressure distribution, environmental loads (temperature, pressure), and long-term stability, a reliable seal is achieved throughout its entire life cycle, from initial sealing to operational sealing.

[0026] Combination Figure 4 In one embodiment of this utility model, the depth of the limiting groove of the top cover 9 is no greater than the thickness of the upper cover 8. This design avoids a gap between the top cover 9 and the upper cover 8 when the lower end of the top cover 9 is in contact with the top surface of the flowmeter body 1, preventing a tight seal between the lower end of the upper cover 8 and the upper end of the flowmeter body 1. Alternatively, during long-term operation of the gear flowmeter, creep, thermal expansion, or media corrosion can reduce the preload stress (stress relaxation), ultimately leading to leakage of the medium within the metering chamber.

[0027] In a preferred embodiment of this utility model, combined with Figure 1 and Figure 3As shown. The flowmeter body 1 is a gear flowmeter body with an integrally machined (cast) flange structure. Its interior has a metering groove 6 for accommodating a pair of meshing metering gears, enabling the gear flowmeter to perform fluid measurement using a volumetric method. A top cover 8 is installed at the upper end of the flowmeter body 1. The inner surface of the top cover 8 and the metering groove 6 together define a closed metering cavity, allowing the aforementioned set of gears to operate in a sealed manner within this cavity for meshing. To enhance the pressure resistance of the flowmeter body 1 and the top cover 8, the volumetric flowmeter also includes a base plate 10 and a top cover 9. The base plate 10 is installed at the lower end of the flowmeter body 1, and the top cover 9 is installed at the upper end of the top cover 8. Through cooperation with the base plate 10, the flowmeter body 1 and the top cover 8 form a gear flowmeter resistant to strong acids and alkalis. At the same time, the depth of the limiting groove of the top cover 9 can be reduced by at least 0.1 mm compared with the thickness of the top cover 8. Through this 0.1 mm gap, the meshing gears in the metering cavity of the gear flow meter are prevented from wearing down the flow meter body 1 and / or the top cover 8 due to creep, thermal expansion or media corrosion during long-term operation, which would eventually lead to a reduction in the pre-tightening stress (stress relaxation) between the liquid contact surfaces of the gear flow meter and cause media leakage.

[0028] In another preferred embodiment of this utility model, combined with Figure 2 and Figure 4 As shown. The top cover 9 and the bottom plate 10 can be made of metals with high stress, such as stainless steel, carbon steel, and aluminum alloy. A threaded hole 2 is provided in the top cover 9, allowing screws 12 to pass through the top cover 9 and bottom plate 10 to press the flowmeter body 1 and the top cover 8 together and engage with the sealing ring to form a sealed space within the metering chamber. Furthermore, the inter-material stress and tension between PTFE and stainless steel effectively prevent media leakage caused by creep, thermal expansion, or media corrosion in the metering chamber made of PTFE.

[0029] In one embodiment of this utility model, the base plate 10 and the top cover 9 can also be connected by threads. As long as the installation distance between the top cover 9 and the base plate 10 is greater than the total height of the flow meter body 1 and the top cover 8, the flow meter body 1 and the top cover 8 clamped between the top cover 9 and the base plate 10 can be ensured to be tightly clamped, that is, the metering cavity is sealed and leak-proof.

[0030] In the experimental group, conventional PTFE volumetric flow meters typically have a pressure resistance of around 0.6 MPa, while gear flow meters with an integrated flange structure, under the clamping action of the top cover 9 and the bottom plate 10, can achieve a pressure resistance of at least 3 MPa, and the pressure drop during pressure holding reaches 0.01 MPa, which is far lower than the design requirement of 0.1 MPa. Its performance far exceeds expectations.

[0031] In practical use, the working principle of this utility model is as follows:

[0032] This invention provides a volumetric flow meter resistant to strong acids and alkalis. Its liquid-contact surface is made of PTFE (polytetrafluoroethylene), a material with extremely strong chemical inertness, capable of withstanding corrosive media such as strong acids, strong alkalis, and organic solvents. It is suitable for highly corrosive fluid environments in chemical, pharmaceutical, and environmental industries. Its extremely low coefficient of friction (approximately 0.04-0.1) significantly reduces wear during gear rotation, extending service life, and is particularly suitable for measuring high-viscosity fluids (such as heavy oil and resin). This characteristic also reduces energy loss and improves long-term operational stability. Furthermore, it can operate stably within an extreme temperature range of -200℃ to 260℃, making it suitable for special conditions such as high-temperature steam and low-temperature refrigerants, avoiding the sealing failure problems caused by thermal expansion and contraction of traditional materials. Since gear flow meters are particularly suitable for measuring fluids with viscosities up to 10000 Pa·s (such as resin and asphalt), the low-friction characteristics of PTFE further optimize gear rotation efficiency and reduce measurement errors caused by viscous resistance. This allows for widespread and effective application in the petroleum, chemical, and pharmaceutical industries. Meanwhile, the integrated PTFE gear flow meter with flange connection can be used to monitor reactor discharge, pipeline transportation, and other processes, providing real-time flow data to optimize process parameters. It also avoids safety hazards caused by media leakage, ensuring long-term stable operation of the flow meter. Furthermore, the integrated design facilitates remote deployment and long-term monitoring, reducing the need for external cables, interfaces, and installation accessories, thus lowering initial investment and subsequent maintenance costs. The long lifespan of PTFE material also reduces replacement frequency, further saving on total cost of ownership.

[0033] In summary, this utility model's volumetric flow meter, resistant to strong acids and alkalis, adopts an integrated PTFE gear flow meter structure design. Its body uses a one-piece machined flange connection, enhancing tensile and pressure resistance. Simultaneously, the top cover 9 and bottom plate 10 are made of metal and connected by screws 12, locking the PTFE body to the top cover 8. This prevents cracking caused by direct screw contact with the PTFE body during prolonged use, enhancing the pressure resistance of the integrated volumetric flow meter. Furthermore, a sealing ring groove 5 is provided between the flow meter body 1 and the top cover 8, achieving a seal through the sealing ring. The top cover 9 has a limiting groove along the outer contour edge of the top cover 8, ensuring that the top cover 9 effectively confines the top cover 8 to the upper side of the flow meter body 1. External mechanical force effectively isolates the sealing material from the contact surface, preventing media leakage. Meanwhile, the top cover 9 and the bottom plate 10 are made of metal and are connected by screws 12 to lock the PTFE body to the top cover 8, effectively preventing media leakage caused by creep, thermal expansion, or media corrosion in the PTFE metering chamber. Through its pressure resistance test, this flow meter can achieve a pressure resistance of at least 3MPa, far exceeding the pressure resistance of conventional PTFE flow meters, ensuring high safety.

[0034] This utility model discloses a volumetric flow meter resistant to strong acids and alkalis. Through synergistic optimization of materials and structure, it achieves comprehensive advantages such as high precision, strong corrosion resistance, and easy maintenance, making it particularly suitable for scenarios with stringent reliability requirements, such as chemical, energy, and environmental protection industries. Furthermore, to address the issue of poor tensile strength and wear resistance of integrated PTFE during daily use, stainless steel top covers 9 and bottom plates 10 are respectively installed at the upper and lower ends of the flow meter to ensure effective clamping of the gear flow meter and prevent leakage of the medium within the metering chamber during long-term use. Through the above design, it can be widely used to monitor reactor discharge, pipeline transportation, and other processes, providing real-time flow data feedback to optimize process parameters, while avoiding safety hazards caused by medium leakage and ensuring long-term stable operation of the flow meter. Therefore, this utility model effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0035] The above are merely specific embodiments of this utility model, but the technical features of this utility model are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on this utility model to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of this utility model.

Claims

1. A volumetric flow meter resistant to strong acids and alkalis, comprising a flow meter body (1), characterized in that, The flow meter body (1) has a metering groove (6) for accommodating a pair of meshing metering gears. A top cover (8) is installed on the upper end of the flow meter body (1). The inner surface of the top cover (8) and the metering groove (6) together define a closed metering cavity. A bottom plate (10) is installed on the bottom surface of the flow meter body (1). A top cover (9) is installed on the top cover (8).

2. The volumetric flow meter resistant to strong acids and alkalis according to claim 1, characterized in that: The flow meter body (1) has two sets of connecting pipes (7) installed on its outer wall. The two ends of the two sets of connecting pipes (7) are the inlet end (3) and the outlet end (4) respectively. The inlet end (3) and the outlet end (4) are both flange structures. The flow meter body (1) is integrally formed with the connecting pipes (7) and flange structures on both sides.

3. A volumetric flow meter resistant to strong acids and alkalis according to claim 2, characterized in that: The flow meter body (1) and the threaded hole (2) are both made of PTFE (polytetrafluoroethylene). The flow meter body (1) is provided with a sealing ring groove (5) along the outer edge of the metering groove (6). The flow meter body (1) and the top cover (8) are sealed by a sealing ring installed on the sealing ring groove (5).

4. A volumetric flow meter resistant to strong acids and alkalis according to claim 3, characterized in that: The flow meter body (1) and the top cover (8) are provided with through holes (11) and sliding holes (13) along the outer circumference of the sealing ring groove (5). The top cover (9) and the bottom plate (10) are provided with threaded holes (2) on their outer walls. The number and position of the threaded holes (2) correspond one-to-one with the through holes (11) and sliding holes (13). The threaded holes (2) at the bottom plate (10) are connected to screws (12) by screws (12), and the screws (12) move in the through holes (11) and sliding holes (13) and extend to the threaded holes (2) at the top cover (9). The bottom plate (10) is combined with the flow meter body (1), the top cover (8) and the top cover (9) into a whole by screws (12).

5. A volumetric flow meter resistant to strong acids and alkalis according to claim 4, characterized in that: The top cover (9) and the bottom plate (10) are both made of metal materials, and the top cover (9) has a limiting groove along the outer contour edge of the top cover (8).

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