Liquefied gas acid-base property determination device and determination method

Abstract

The invention provides a liquefied gas acid-base property determination device and a determination method, relates to the field of liquefied gas detection, and aims to solve the problem that the existing liquefied gas acid-base property is inconvenient to determine, a test container and a protective sleeve are configured, a containing cavity for containing liquefied gas to be detected, pH test paper and the protective sleeve is formed in the test container, and a protective cavity for fixing the pH test paper is formed in the protective sleeve; the shape is maintained, and folding and damage are avoided; the protective sleeve is provided with a plurality of contact holes, so that gas-liquid two-phase liquefied gas is allowed to freely permeate into the protective cavity, the pH test paper is directly contacted with acid-base substances, a distilled water medium is not needed, the problems of poor intersolubility and emulsion are avoided, the original gas-liquid balance is prevented from being damaged, and the requirements of liquefied gas acid-base property determination are met.

Description

Technical Field

[0001] This invention relates to the field of liquefied petroleum gas (LPG) detection, and specifically to an LPG acidity / alkalinity measuring device and method. Background Technology

[0002] The acidity or alkalinity of liquefied petroleum gas (LPG) affects its combustion performance; acidic LPG can also corrode equipment. To ensure normal equipment operation, reduce environmental pollution, and achieve complete combustion, it is necessary to determine the acidity or alkalinity of LPG. Currently, there is a lack of suitable equipment and specific methods for determining the acidity or alkalinity of LPG.

[0003] Existing technologies disclose waste gas acidity / alkalinity detection devices, which include a housing with pipes installed inside. A distillation tank is located inside and at the top of the housing, allowing distilled water mixed with waste gas to drip onto pH test paper for detection. However, waste gas differs significantly from liquefied petroleum gas (LPG); it is predominantly gaseous and requires distilled water to absorb acidic and alkaline substances (such as...). , When liquefied petroleum gas (LPG) forms an aqueous solution, it is then dropped onto test paper for color development. However, LPG and distilled water have poor miscibility, and mixing them may form an emulsion. This prevents the effective transfer of acidic and alkaline substances to the water, resulting in inaccurate color development on the test paper. Furthermore, LPG is easily vaporized at room temperature and pressure. Introducing distilled water may cause significant evaporation due to pressure changes, affecting the safety of the testing environment. Therefore, the high liquid content of LPG makes it impossible to effectively extract acidic and alkaline substances through distilled water absorption. Instead, it may disrupt the original gas-liquid balance, leading to test failure and failing to meet the requirements for determining the acidity and alkalinity of LPG. Summary of the Invention

[0004] The purpose of this invention is to address the deficiencies of existing technologies by providing a device and method for determining the acidity and alkalinity of liquefied petroleum gas (LPG). The test container has an internal cavity that holds the LPG to be tested, pH test paper, and a protective sleeve. The protective sleeve has an internal cavity that holds the pH test paper in place, maintaining its shape and preventing folding or damage. The protective sleeve has multiple contact holes that allow the gas and liquid phases of the LPG to freely permeate into the protective cavity, enabling the pH test paper to directly contact the acidic or alkaline substances without the need for distilled water as an intermediary.

[0005] The first objective of this invention is to provide a device for determining the acidity and alkalinity of liquefied petroleum gas, which employs the following solution: It includes a test container and a protective sleeve. The protective sleeve is located inside the cavity of the test container. The test container is equipped with a control valve that connects to the cavity for connecting to the liquefied gas source to be tested. The protective sleeve has a protective cavity to hold the pH test paper and maintain the shape of the pH test paper inside the protective sleeve. The protective sleeve has multiple contact holes to connect the protective cavity and the cavity.

[0006] Furthermore, the test container is equipped with a support frame, and the protective sleeve is connected to the inner wall of the cavity through the support frame to maintain the relative position of the protective sleeve and the cavity.

[0007] Furthermore, along the direction of the liquefied gas injection cavity, control valves are installed at both ends of the test container, and the protective sleeve is located on the line connecting the control valves at both ends of the test container.

[0008] Furthermore, the control valve is a needle valve.

[0009] Furthermore, the test container includes a cylinder and a cap. One end of the cylinder is sealed and a control valve is installed thereon. The other end is open and can be sealed by a detachable fit with the cap, which is equipped with a control valve.

[0010] Furthermore, a sealing ring is installed at the mating position between the cap and the cylinder.

[0011] Furthermore, contact holes are provided on each of the axial sides of the protective sleeve.

[0012] A second objective of the present invention is to provide a method for determining the acidity or alkalinity of liquefied petroleum gas (LPG), utilizing the LPG acidity / alkalinity determination apparatus provided as in the first objective, comprising: Place the pH test strip into the protective cavity of the protective sleeve, and then place the protective sleeve with the pH test strip inside the cavity. The cavity is connected to the liquefied gas source to be tested by a control valve, so that the liquefied gas is filled into the cavity. After it is full, the cavity is disconnected from the liquefied gas source to be tested. The test container was heated and kept warm in a water bath. After the set time, the pH test paper was taken out to confirm the acidity or alkalinity of the liquefied gas.

[0013] Furthermore, when the liquefied gas is filled into the cavity, it impacts the protective sleeve so that the liquefied gas passes through the contact hole and comes into contact with the pH test paper.

[0014] Furthermore, before removing the pH test strip, open the control valve to depressurize the test container, and then remove the pH test strip.

[0015] Compared with the prior art, the advantages and positive effects of this invention are: To address the current inconvenience of measuring the acidity and alkalinity of liquefied petroleum gas (LPG), a test container and protective sleeve are designed. The test container forms a cavity to hold the LPG to be tested, pH test paper, and the protective sleeve. The protective sleeve forms a protective cavity to fix the pH test paper, maintain its shape, and prevent folding or damage. The protective sleeve has multiple contact holes, allowing the gas and liquid phases of the LPG to freely permeate into the protective cavity, enabling the pH test paper to directly contact the acidic and alkaline substances without the need for distilled water as an intermediary. This avoids problems such as poor miscibility and emulsions, prevents disruption of the original gas-liquid balance, and meets the needs of LPG acidity and alkalinity measurement.

[0016] A support frame is installed inside the test container cavity. One end of the support frame is fixed to the inner wall of the cavity, and the other end is connected to the protective sleeve to form a rigid support. The protective sleeve is in a fixed position, and the pH test strip remains stable during the test, avoiding inconsistent color development areas due to positional displacement, thus improving the repeatability and reliability of the test results.

[0017] Control valves are installed at both ends of the test container, and the protective sleeve is located on the line connecting the two control valves, i.e., on the central path of the liquefied gas flow. The axial flow design ensures that the liquefied gas forms a stable flow field within the cavity, and the contact holes on each side of the protective sleeve can contact acidic or alkaline substances, avoiding color deviation caused by insufficient local contact.

[0018] The circumferential contact holes allow the pH test paper to be fully exposed to the liquefied gas, resulting in a more uniform color reaction and avoiding deviations in acidity and alkalinity judgments caused by insufficient local contact. It is especially suitable for uniform detection when liquefied gas and liquid coexist. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is a schematic diagram of a liquefied gas acidity / alkalinity measuring device in one or more embodiments of the present invention.

[0021] The components include: 1. Control valve; 2. Cover; 3. Sealing ring; 4. Cavity; 5. Test container; 6. Support frame; 7. Protective sleeve; and 8. Contact hole. Detailed Implementation

[0022] Example 1 In a typical embodiment of the present invention, such as Figure 1 A device for determining the acidity and alkalinity of liquefied gas is presented.

[0023] Existing technologies for detecting the acidity and alkalinity of exhaust gases cannot be directly applied to the determination of the acidity and alkalinity of liquefied petroleum gas (LPG). Exhaust gases are primarily gaseous and require the absorption of acidic and alkaline substances through distilled water. However, LPG is primarily liquid at room temperature and pressure, with a mixture of gas and liquid, and has poor miscibility with distilled water. Using a "distilled water absorption" method would result in ineffective transfer of acidic and alkaline substances, and could even disrupt the gas-liquid balance. The open-chamber and distillation chamber design of exhaust gas detection devices cannot meet the sealing and safety requirements of LPG. LPG is easily vaporized, flammable, and explosive, and changes in gas pressure can lead to ignition risks, affecting detection accuracy and operational safety. Based on this, this embodiment provides an LPG acidity and alkalinity determination device. The test container 5 forms a cavity 4 inside to accommodate the LPG to be tested, pH test paper, and a protective sleeve 7. The protective sleeve 7 forms a protective cavity inside to fix the pH test paper and maintain its shape. The pH test paper inside the protective sleeve 7 is in direct contact with the LPG injected into the cavity 4, thereby performing acidity and alkalinity determination.

[0024] like Figure 1 As shown, the liquefied petroleum gas (LPG) acidity / alkalinity testing device mainly includes a test container 5 and a protective sleeve 7. A control valve 1 is installed on the test container 5 to connect to the LPG source, forming a sealed cavity 4 to ensure that the LPG is stored under controllable pressure, preventing leakage or evaporation. The protective sleeve 7 is located inside the cavity 4, forming an internal protective chamber to fix the pH test paper, maintaining its shape and preventing folding or damage that could affect the accuracy of the measurement. The protective sleeve 7 has multiple contact holes 8, allowing LPG to freely permeate into the protective chamber, enabling the pH test paper to directly contact acidic or alkaline substances without the need for distilled water as an intermediary.

[0025] Abandoning the "distilled water absorption" method, this system utilizes the inherent gas-liquid properties of liquefied petroleum gas (LPG) to achieve direct reaction between acidic and alkaline substances and pH test paper via contact holes 8 in the protective sleeve 7, avoiding issues related to poor miscibility and emulsions. The sealed container design ensures stable pressure during testing, preventing LPG vaporization from affecting the testing environment and meeting safety requirements. The elimination of distilled water avoids LPG evaporation due to pressure changes, ensuring a safe operating environment while simplifying testing procedures and enhancing applicability in industrial settings.

[0026] The protective sleeve 7 maintains the shape of the pH test strip, and the contact hole 8 design ensures uniform contact of the liquefied gas with the test strip, avoiding color deviation caused by test strip deformation or insufficient contact, and accurately reflecting the acidity or alkalinity of the liquefied gas. Direct contact detection avoids dilution or interference from distilled water, ensuring that the concentration of acidic and alkaline substances is not affected, and the color development results are more reliable.

[0027] The sealed test container 5 meets the pressure resistance requirements of liquefied gas. The test container 5 can withstand a static pressure of 7.0MPa, has good sealing performance, reduces the risk of leakage, and is suitable for flammable and explosive liquefied gas testing scenarios.

[0028] A dedicated device was designed to address the gas-liquid coexistence characteristics of liquefied petroleum gas (LPG), solving the problem that existing waste gas detection devices are not applicable. This provides a specific solution for determining the acidity and alkalinity of LPG and promotes the development of detection technology in the LPG field.

[0029] like Figure 1 As shown, the support frame 6 ensures the relative position of the protective sleeve 7 and the cavity 4, maintaining a fixed posture of the protective sleeve 7 within the test container 5. This prevents displacement of the protective sleeve 7 due to impacts during liquefied gas injection or container shaking, which could affect the uniformity of contact between the pH test paper and the liquefied gas. It also maintains the distance between the protective sleeve 7 and the inner wall of the cavity 4, preventing the protective sleeve 7 from adhering to the cylinder wall and ensuring that the liquefied gas can penetrate into the protective cavity from all directions through the contact hole 8.

[0030] Specifically, a support frame 6 is provided inside the cavity 4 of the test container 5. One end of the support frame 6 is fixed to the inner wall of the cavity 4, and the other end is connected to the protective sleeve 7. In this embodiment, the support frame 6 and the inner wall of the cavity 4, and the support frame 6 and the protective sleeve 7 can adopt detachable structures such as buckles and bolts, so that the support frame 6 forms a rigid support for the protective sleeve 7.

[0031] It should be noted that the layout of the support frame 6 should avoid obstructing the contact hole 8 to ensure smooth flow of liquefied gas. The protective sleeve 7 is fixed in position, keeping the pH test strip stable during the test, avoiding inconsistent color development areas due to positional shifts, and improving the repeatability and reliability of the test results.

[0032] Control valves 1 are installed at both ends of the test container 5. The control valves 1 can be needle valves. The protective sleeve 7 is located on the line connecting the two control valves 1, that is, on the center path of the liquefied gas flow. This allows the liquefied gas to be injected and discharged axially along the test container 5, ensuring that the airflow passes evenly through the protective sleeve 7, avoiding the formation of dead zones, and ensuring that all parts of the pH test paper are in full contact with the liquefied gas.

[0033] When injecting liquefied petroleum gas (LPG), the LPG enters from one control valve 1, passes axially through the contact hole 8 of the protective sleeve 7, and comes into contact with the pH test paper inside the protective sleeve 7, remaining in the test container 5, ensuring that the protective sleeve 7 is in full circumferential contact with the LPG. After the test is completed, the LPG is discharged from the other control valve 1.

[0034] The axial flow design allows the liquefied gas to form a stable flow field within the cavity 4, and the contact holes 8 on each side of the protective sleeve 7 can contact acidic and alkaline substances, avoiding color deviation caused by insufficient local contact.

[0035] Liquefied petroleum gas (LPG) is easily vaporized, requiring precise control of the filling volume and pressure via valves to prevent overpressure leading to container leakage or excessive vaporization affecting the testing environment. In this embodiment, a 1-6mm needle valve is selected. The LPG injection flow rate and pressure are controlled by adjusting the valve core opening. A pressure gauge is used to monitor the pressure within cavity 4. A pressure gauge interface can be added to the test container 5 as needed. The fine adjustment function of the needle valve ensures that the pressure within cavity 4 remains stable within a safe range (e.g., ≤7.0MPa), while controlling the LPG filling volume to avoid excessive injection leading to liquid residue or vaporization risks.

[0036] The detachable structure facilitates the replacement of pH test strips and cleaning of the container's inner wall. The sealing ring 3 ensures the high airtightness of the cavity 4, preventing liquefied gas leakage. Specifically, the test container 5 consists of a cylinder and a cap 2. One end of the cylinder is sealed and fitted with a control valve 1, while the other end is open and detachably connected to the cap 2 via threads. An O-ring 3, which can be made of fluororubber, is installed on the mating surface between the cap 2 and the cylinder. Tightening the threads to the O-ring 3 creates a sealed structure. The detachable design reduces device maintenance costs and facilitates reuse; the high airtightness ensures no leakage of liquefied gas during testing, guaranteeing operational safety and testing accuracy, and preventing external air interference with acidity and alkalinity.

[0037] Ensure that the pH test paper inside the protective sleeve 7 is in contact with the liquefied gas on all axial sides, avoiding limited color development areas due to uneven distribution of contact holes 8. The protective sleeve 7 can be made of polytetrafluoroethylene (PTFE), with contact holes 8 evenly distributed on all axial sides of the protective sleeve 7. The hole diameter is 3-6 mm, and the hole spacing is 2-5 mm, ensuring that the liquefied gas can penetrate into the protective cavity from different directions. The circumferential contact holes 8 expose the pH test paper to the liquefied gas from all directions, resulting in a more uniform color development reaction and avoiding deviations in acidity and alkalinity judgment due to insufficient local contact. This is especially suitable for uniform detection when liquefied gas and liquid coexist.

[0038] The design of the support frame 6, detachable cover 2, and sealing ring 3 balances device stability and ease of maintenance, meeting the needs of repeated use in industrial settings. Axial airflow path, full-circumferential contact holes 8, and needle valve control ensure uniform contact of liquefied gas with the pH test paper, with controllable pressure and sample volume, reducing detection errors. The sealed cavity 4, in conjunction with the needle valve, prevents liquefied gas leakage or overpressure risks, making it suitable for safe testing in flammable and explosive environments. It specifically addresses the issue of the gas-liquid coexistence characteristics of liquefied gas and its poor miscibility with distilled water, filling a technological gap and providing a dedicated solution for the determination of the acidity and alkalinity of liquefied gas.

[0039] Example 2 In another typical embodiment of the present invention, such as Figure 1 A method for determining the acidity and alkalinity of liquefied petroleum gas (LPG) is provided, utilizing the LPG acidity and alkalinity determination device as described in Example 1.

[0040] A method for determining the acidity or alkalinity of liquefied petroleum gas, comprising: Place the pH test paper into the protective cavity of the protective sleeve 7, and place the protective sleeve 7 with the pH test paper into the cavity 4; The cavity 4 is connected to the liquefied gas source to be tested by the control valve 1, so that the liquefied gas is filled into the cavity 4. When the liquefied gas is filled into the cavity 4, the liquefied gas impacts the protective sleeve 7 so that the liquefied gas passes through the contact hole 8 and contacts the pH test paper. After it is filled, the cavity 4 is disconnected from the liquefied gas source to be tested. The test container 5 is heated and kept warm in a water bath. After the set time, the control valve 1 is opened to release the pressure in the test container 5. Then, the pH test paper is taken out to confirm the acidity or alkalinity of the liquefied gas.

[0041] In this embodiment, in conjunction with Embodiment 1 and Figure 1 This paper provides a detailed explanation of the method for determining the acidity and alkalinity of liquefied petroleum gas.

[0042] First, install the pH test strips and position the protective sleeve 7. Place the pH test paper into the protective cavity of the protective sleeve 7 and fix it to the cavity 4 of the test container 5 by the support frame 6, ensuring that the protective sleeve 7 is located in the center of the liquefied gas flow path.

[0043] The protective sleeve 7 is used to maintain the flat shape of the pH test strip and prevent it from folding or breaking. At the same time, the contact hole 8 of the protective sleeve 7 is designed to provide a channel for the permeation of liquefied gas, ensuring that the test strip is in direct contact with acidic and alkaline substances.

[0044] Then, the liquefied gas sample was filled and the cavity 4 was sealed. The cavity 4 is connected to the liquefied gas source through needle valves at both ends. The opening of valve 1 is controlled to allow liquefied gas to fill the cavity 4. After it is full, the valve is closed to cut off the gas source.

[0045] The needle valve is used to precisely control the sample filling volume and pressure (refer to the 7.0MPa static pressure design in the comparative document) to avoid overpressure leakage or excessive vaporization; the sealed cavity 4 ensures the stable existence of the gas-liquid two phases of liquefied gas, providing a consistent environment for subsequent detection.

[0046] Then, water bath heating and heat preservation are carried out; Immerse test container 5 in a constant temperature water bath (e.g., 40℃) and keep it warm for 3-5 minutes before removing it.

[0047] By increasing the temperature, the volatilization and diffusion of acidic and alkaline substances in liquefied petroleum gas (such as the vaporization of liquid sulfides) are promoted, accelerating the colorimetric reaction with pH test paper, shortening the detection time, and improving the colorimetric sensitivity.

[0048] During sample filling, the liquefied gas flow rate is controlled to impact the surface of the protective sleeve 7. Fluid dynamics propel the liquefied gas rapidly through the contact hole 8, ensuring full contact with the pH test paper within the protective chamber. This dynamic impact prevents static stratification of the liquefied gas within the cavity 4, ensuring uniform permeation of both gas and liquid phases into the protective chamber. This method is particularly suitable for the rapid release of acidic and alkaline substances from liquefied gas. Accelerating the contact process allows the pH test paper to develop uniform color within a short time, reducing detection time.

[0049] After the test is completed, first open one needle valve to slowly release the pressure. Once the pressure inside chamber 4 has dropped to normal atmospheric pressure, remove the cap 2 and take out the pH test strip. This is to avoid disassembling under pressure, which could cause a sudden release of liquefied gas, leading to safety accidents (such as explosions or frostbite) or damage to the test strip due to the airflow. After depressurization, the gas-liquid balance inside chamber 4 will be stable, preventing backflow of outside air when removing the test strip and affecting the accuracy of the acidity / alkalinity determination.

[0050] The protective sleeve 7 maintains the shape of the test strip, the impact-type sample filling ensures uniform contact, the pressure relief operation avoids external interference, and the multiple designs make the color development results repeatable (e.g., pH value deviation ≤0.5 in multiple tests), meeting the precision requirements of quality control in industrial production.

[0051] The closed cavity 4 and needle valve control the pressure, and the pressure relief step eliminates safety hazards, making the method suitable for on-site testing; the "direct contact" mode that does not require distilled water avoids the problem of poor miscibility between liquefied gas and water, and can be adapted to liquefied gas with different components (such as propane and butane mixtures).

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for measuring the acidity or basicity of a liquefied gas, characterized by comprising: The test container and the protective sleeve are arranged in the cavity of the test container, and the control valve is arranged on the test container to connect the cavity and the source of the liquefied gas to be detected.

2. The apparatus for measuring the acidity or basicity of a liquefied gas according to claim 1, wherein The test container is provided with a support frame, and the protective sleeve is connected to the inner wall of the cavity through the support frame to maintain the relative position of the protective sleeve and the cavity.

3. The apparatus for measuring the acidity or basicity of a liquefied gas according to claim 1, wherein The control valves are arranged at the two ends of the test container along the direction of the liquefied gas injection into the cavity, and the protective sleeve is arranged on the line connecting the two control valves.

4. The apparatus for measuring the acidity or basicity of a liquefied gas according to claim 3, wherein The control valve is a needle valve.

5. The apparatus for measuring the acidity or basicity of a liquefied gas according to claim 3 or 4, wherein The test container comprises a barrel and a cover, one end of the barrel is sealed and provided with a control valve, the other end is open and sealed by detachable cooperation of the cover, and the cover is provided with a control valve.

6. The apparatus for measuring the acidity or basicity of a liquefied gas according to claim 5, wherein The sealing ring is arranged at the cooperation position of the cover and the barrel.

7. The apparatus for measuring the acidity or basicity of a liquefied gas according to claim 1, wherein The protective sleeve is provided with contact holes on each side surface in the axial direction.

8. A method for measuring the acidity or basicity of a liquefied gas using the apparatus for measuring the acidity or basicity of a liquefied gas according to any one of claims 1 to 7, characterized by, The method comprises the following steps: The pH test paper is placed in the protective cavity of the protective sleeve, and the protective sleeve with the pH test paper is arranged in the cavity. The cavity is connected to the source of the liquefied gas to be detected through the control valve, the liquefied gas is filled into the cavity, and the connection between the cavity and the source of the liquefied gas to be detected is cut off after the cavity is filled. The test container is heated in water bath, and the pH test paper is taken out to confirm the acidity and alkalinity of the liquefied gas after a set time.

9. The method for determining the basicity of a liquefied gas according to claim 8, wherein When the liquefied gas is filled into the cavity, the liquefied gas impacts the protective sleeve, so that the liquefied gas passes through the contact hole and contacts the pH test paper.

10. The method of claim 8, wherein the liquid acid or base is selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, phosphoric acid, sodium hydroxide, potassium hydroxide, and combinations thereof. Before the pH test paper is taken out, the control valve is opened to release the pressure of the test container, and then the pH test paper is taken out.

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