Pressure reducing device for measuring residual gas content of a gas cylinder

Abstract

The present application relates to the measuring gas cylinder residual gas content pressure reducing device, including connecting on the gas guide pipe and respectively with the calculation unit connection pressure reducer and temperature measuring device, the calculation unit connection volume selection device, gas selection device and residual gas display device;The calculation unit is configured to: obtain the gas pressure P and temperature in the gas cylinder obtained by the pressure reducer and the temperature measuring device, the volume selection device selects the gas cylinder volume, and the gas selection device selects the gas type in the gas cylinder;According to the size between the temperature and the critical temperature of the selected gas under pressure P, determine whether the gas in the gas cylinder is gaseous or gas-liquid mixed state;According to the corresponding equation of state, the amount of substance of the residual gas is obtained, the selected gas type and the mass of the gas at the full capacity of the gas cylinder are used to obtain the mass percentage of the residual gas in the total capacity of the gas cylinder and send it to the residual gas display device;When the percentage meets the set threshold value, a warning signal is sent.

Description

Technical Field

[0001] This invention relates to the field of gas cylinder pressure regulator technology, specifically a pressure reducing device for measuring the remaining gas content in a gas cylinder. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] In industry, commonly used gases such as hydrogen, oxygen, and sulfur hexafluoride are stored, transported, and used in gas cylinders. Pressure reducing valves at the cylinder openings decrease the outlet pressure to meet operational requirements. Gas cylinders have a simple structure but limited storage capacity. As gas is released, the internal pressure gradually decreases. In practical use, it is necessary to know the remaining gas content in the cylinder to replace it. Current technology lacks such a device, and pressure estimates must be made manually based on experience. Summary of the Invention

[0004] To address at least one of the technical problems mentioned above, this invention provides a pressure-reducing device for measuring the remaining gas content in a gas cylinder. Using the gas state equation and the current pressure, temperature, and filling volume of the gas cylinder measured by the pressure-reducing device, the "amount of substance" of the remaining gas in the cylinder is obtained. Then, based on the type of gas filled in the cylinder and the standard mass at full capacity, the mass percentage of the remaining gas relative to the total cylinder volume is calculated. The remaining gas content in the cylinder is estimated and displayed based on this mass percentage, thereby reminding the user to replace the gas cylinder.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The first aspect of the present invention provides a pressure reducing device for measuring the remaining gas content of a gas cylinder, comprising: a pressure reducing device and a temperature measuring device connected to a gas delivery tube, the pressure reducing device and the temperature measuring device being respectively connected to a calculation unit, the calculation unit being connected to a volume selection device, a gas selection device and a remaining gas display device;

[0007] The computing unit is configured as follows:

[0008] The gas pressure P and temperature T inside the gas cylinder are obtained from the pressure reducer and temperature measuring device, the gas cylinder volume V is selected by the volume selection device, and the gas type inside the gas cylinder is selected by the gas selection device.

[0009] The gas in the cylinder is determined to be either in a gaseous state or a gas-liquid mixture state based on the relationship between the temperature and the critical temperature of the selected gas under pressure P.

[0010] Based on the equation of state corresponding to the gas in a gaseous or gas-liquid mixed state, the amount of substance M of the remaining gas is obtained. Using the selected gas type and the mass of the gas when the gas cylinder is full, the mass percentage of the remaining gas relative to the total gas cylinder capacity is obtained and sent to the remaining gas display device. When the percentage meets the set threshold, an alert signal is issued.

[0011] When the gas is in the gaseous state, the amount of substance of the remaining gas is obtained using the real gas law. When the gas is in a gas-liquid mixture, the following formula is used:

[0012]

[0013] in:

[0014] a=(1+(0.48508+155171ω-0.15613ω 2 )(1-Tr 0.5 )) 2 ;

[0015] p is the gas pressure obtained through the pressure reducer; V m T is the molar volume of the gas; T is the temperature; T C P is the critical temperature. c The critical pressure; T r The temperature is used for comparison; ω is the eccentricity factor.

[0016] The mass of the remaining gas is obtained by using the amount of substance of the remaining gas and the molar mass corresponding to the gas type.

[0017] Based on the selected gas type and cylinder volume, the mass of the gas when the cylinder is full is obtained. Using the mass of the remaining gas, the percentage of the remaining gas relative to the total cylinder capacity is calculated.

[0018] The pressure regulator is connected to a flow control valve, a high-pressure display device, and a low-pressure display device. The high-pressure display device and the low-pressure display device measure and display the pressure inside the gas cylinder and the pressure after pressure reduction, respectively.

[0019] The air duct has an inlet and an outlet at its two ends, with the pressure reducer located near the inlet and the temperature measuring device near the outlet. The temperature measuring device is connected to the temperature display device.

[0020] Pressure and temperature data acquired by the pressure reducer and temperature measuring device are transmitted to the computing unit via a data transmission line.

[0021] The volume selection device selects the corresponding gas cylinder capacity according to the usage requirements, sends the information to the calculation unit, and displays it on the volume selection device.

[0022] The gas selection device selects the corresponding gas type according to the usage requirements, sends the information to the computing unit, and displays it on the gas selection device.

[0023] The remaining gas display device is equipped with an alarm light. It receives the results from the calculation unit, displays the percentage of remaining gas, and issues a warning signal through the alarm light according to the set threshold.

[0024] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects:

[0025] 1. By using the gas law and pressure reducing device to measure the current pressure, temperature and filling volume of the gas cylinder, and combining this with the type of gas filled in the cylinder, the mass percentage of the remaining gas in the total volume of the cylinder can be obtained. This mass percentage is used as the basis for displaying the remaining gas content in the cylinder. The measurement method is simple and easy to implement, allowing cylinder users to quickly judge the usage status of the gas in the cylinder and reduce the impact caused by insufficient gas content leading to non-refilling.

[0026] 2. The method of displaying the remaining gas in the cylinder using a mass percentage is more intuitive and comprehensive compared to the existing technology that relies on experience and cylinder pressure to judge.

[0027] 3. The required pressure and temperature can be measured using a simple device, and the cylinder volume and gas type can be pre-stored, making the device simple in structure and low in cost. Attached Figure Description

[0028] 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.

[0029] Figure 1 This is a schematic diagram of a pressure reducing device for measuring the residual gas content in a gas cylinder, provided in one or more embodiments of the present invention.

[0030] In the diagram: 1. Inlet port, 2. Pressure reducer, 3. Flow regulating valve, 4. High pressure display device, 5. Low pressure display device, 6. Temperature measuring device, 7. Temperature display device, 8. Air guide pipe, 9. Data transmission line, 10. Volume selection device, 11. Gas selection device, 12. Calculation unit, 13. Remaining gas display device, 14. Warning light, 15. Outlet port, 16. Housing. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] As described in the background section, gas cylinders have a simple structure and limited gas storage capacity. As gas is released, the pressure inside the cylinder gradually decreases. In actual use, it is necessary to know the remaining gas content in the cylinder in order to replace it. Existing technology lacks a similar device and can only estimate the pressure based on the current pressure of the cylinder through manual experience.

[0035] The following embodiment provides a pressure reducing device for measuring the remaining gas content in a gas cylinder. Using the gas state equation and the current pressure, temperature, and filling volume of the gas cylinder measured by the pressure reducing device, the "amount of substance" of the remaining gas in the gas cylinder is obtained. Then, based on the type of gas filled in the gas cylinder and the standard mass when the cylinder is full, the mass percentage of the remaining gas relative to the total volume of the gas cylinder is calculated. The remaining gas content in the gas cylinder is estimated and displayed based on the mass percentage, thereby reminding the user to replace the gas cylinder.

[0036] Example 1:

[0037] like Figure 1 As shown, the purpose of this embodiment is to provide a pressure reducing device for measuring the remaining gas content in a gas cylinder, including: a pressure reducing device 2 and a temperature measuring device 6 connected to a gas guide pipe 8. The pressure reducing device 2 and the temperature measuring device 6 are respectively connected to a calculation unit 12. The calculation unit 12 is connected to a volume selection device 10, a gas selection device 11 and a remaining gas display device 13.

[0038] The computing unit 12 is configured as follows:

[0039] The gas pressure P and temperature T inside the gas cylinder are obtained by pressure reducer 2 and temperature measuring device 6, the gas cylinder volume V is selected by volume selection device 10, and the gas type inside the gas cylinder is selected by gas selection device 11.

[0040] The gas in the cylinder is determined to be in a gaseous or gas-liquid mixed state based on the relationship between temperature T and the critical temperature of the selected gas under pressure P.

[0041] Based on the equation of state corresponding to the gas in a gaseous state or a gas-liquid mixture state, the amount of substance M of the remaining gas is obtained. Using the selected gas type and the mass of the gas when the gas cylinder is full, the percentage of remaining gas is obtained and sent to the remaining gas display device. When the percentage meets the set threshold, an alert signal is issued.

[0042] Pressure reducer 2 is connected to flow regulating valve 3, high pressure display device 4 and low pressure display device 5. High pressure display device 4 and low pressure display device 5 measure and display the pressure inside the gas cylinder and the pressure after pressure reduction, respectively.

[0043] The two ends of the air duct 8 are the air inlet 1 and the air outlet 15, respectively. The pressure reducer 2 is close to the air inlet 1, and the temperature measuring device 6 is close to the air outlet 15. The temperature measuring device 6 is connected to the temperature display device 7.

[0044] The pressure and temperature data acquired by the pressure reducer 2 and the temperature measuring device 6 are sent to the calculation unit 12 via the data transmission line 9.

[0045] The volume selection device 10 selects the corresponding gas cylinder capacity according to the usage requirements, sends it to the calculation unit 10, and displays it on the volume selection device 10.

[0046] The gas selection device 11 selects the corresponding gas type according to the usage requirements, sends it to the calculation unit 10, and displays it on the gas selection device 11.

[0047] The remaining gas display device 13 is equipped with an alarm light 14. It receives the result from the calculation unit 12, displays the percentage of remaining gas, and issues a reminder signal through the alarm light 14 according to the set threshold.

[0048] In use, the inlet port 1 is connected to the outlet port of the high-pressure gas cylinder. Gas flows through the gas guide pipe 8, pressure reducer 2, and temperature measuring device 6 before exiting through the outlet port 15 to achieve pressure reduction. The pressure reducer 2 itself has the ability to test the current pressure inside the cylinder and the pressure after pressure reduction. The pressure reducer 2 measures the gas pressure inside the high-pressure gas cylinder, and the temperature measuring device 6 measures the temperature of the gas inside the high-pressure gas cylinder. The volume selection device 10 selects the capacity of the gas cylinder to which the device is installed. The gas selection device 11 selects the type of gas filled in the cylinder. Finally, the calculation unit 12 calculates the remaining gas content in the cylinder and sends it to the remaining gas display device 13 for display.

[0049] Generally, the volume of a gas can be obtained using the ideal gas law PV = nRT. However, since the physical model of the ideal gas law is more applicable to high temperature and low density conditions, while current high-pressure gas cylinders are generally used in low temperature and high density conditions, the real gas law is used instead.

[0050]

[0051] Where: p is the gas pressure; n is the amount of substance; V is the gas volume; T is the temperature; a and b are van der Waals constants, which have different values ​​for different gases.

[0052]

[0053] in:

[0054] p is the gas pressure; V m T is the molar volume of the gas; T is the temperature; T C P is the critical temperature. c The critical pressure; T r The temperature is used for comparison; ω is the eccentricity factor.

[0055] Among them, through The amount of substance is calculated, through Calculate the comparison temperature.

[0056] Formula (1) applies when the gas inside the cylinder is in a gaseous state, and Formula (2) applies when the gas inside the cylinder is in a gas-liquid mixed state.

[0057] Every substance has a specific temperature above which, no matter how much pressure is increased, the gaseous substance will not liquefy. This temperature is called the critical temperature T of the substance. C For example, the critical temperature of hydrogen is approximately -240 degrees Celsius, the liquefaction temperature of oxygen is approximately -119 degrees Celsius, and the liquefaction temperature of nitrogen is approximately -147 degrees Celsius. Therefore, at room temperature, hydrogen, oxygen, and nitrogen in gas cylinders are all in a gaseous state. If the gas cylinder does not have an insulation layer, hydrogen, oxygen, and nitrogen stored at room temperature are usually in a gaseous state. However, the critical temperature of sulfur hexafluoride is approximately 45.6 degrees Celsius, and the critical temperature of carbon dioxide is approximately 31 degrees Celsius. Compared to gases such as hydrogen, oxygen, and nitrogen, their critical temperatures are closer to room temperature. Therefore, at room temperature, as long as the pressure reaches the critical pressure, sulfur hexafluoride and carbon dioxide can be converted into liquids. In actual use of gas cylinders, sulfur hexafluoride and carbon dioxide inside the cylinder are in a gas-liquid mixed state.

[0058] In equations (1) and (2), P is the pressure of the gas inside the gas cylinder, which is measured by pressure reducer 2.

[0059] V represents the volume of the gas. The volume of the gas cylinder to be measured is selected by the volume selection device 10. For example, the commonly used gas cylinder volumes are 60L, 40L, or 10L. The volume of the gas cylinder can also be selected by customization.

[0060] n is the amount of gaseous substance being measured; R is the ideal gas constant with a value of 8.314; T is the temperature of the gas, measured by temperature measuring device 6.

[0061] The amount of substance n of the gas being measured is calculated.

[0062] The mass of the gas is calculated using the formula m = nM, where m is the mass of the gas being measured.

[0063] M represents the molar mass of the gas being measured. The calculation unit has pre-built molar mass values ​​for commonly used gases, which are selected by the gas selection device 11.

[0064] The total mass m of the gas when the gas cylinder is full can be calculated using the volume selection device 10 and the gas selection device 11. 总 Calculate m / m 总 The percentage of the measured gas in the cylinder can be determined. Based on the percentage, an alarm light will be used to issue a warning signal, and the cylinder user can take corresponding measures according to the warning signal.

[0065] For example:

[0066] When the percentage is greater than or equal to 40%, warning light 14 will turn green, indicating normal operation.

[0067] When the percentage is less than 40% but greater than 10%, warning light 14 will illuminate yellow to indicate a warning.

[0068] When the percentage is less than 10%, warning light 14 will turn red to indicate an alarm.

[0069] Flow regulating valve 3 controls the gas flow rate into the pressure reducing device. High-pressure display device 4 displays the gas pressure value flowing into the pressure reducing device. Low-pressure display device 5 displays the gas pressure value flowing out of the pressure reducing device. Temperature display device 7 displays the gas temperature. Volume selection device 10 manually selects the volume of the high-pressure gas cylinder to be used. Gas selection device 11 manually selects the type of gas in the high-pressure gas cylinder, such as sulfur hexafluoride, hydrogen, and oxygen.

[0070] The calculation of the gas mass percentage is performed by calculation unit 12, as follows:

[0071] 1. Use temperature measuring device 6 to obtain the gas temperature T.

[0072] 2. Use pressure reducer 2 to obtain the gas pressure P inside the gas cylinder.

[0073] 3. Use the gas selection device 11 to obtain the gas type, compare the temperature T with the critical temperature of the gas under pressure P, if it is greater than the critical temperature, select formula (1), if it is less than the critical temperature, select formula (2).

[0074] 4. Use volume selection device 10 to obtain the gas cylinder volume V.

[0075] 5. Use the gas selection device 11 to obtain the amount of substance M of the gas to be measured.

[0076] 6. Calculate the gas mass m using the formula selected in step 3.

[0077] 7. The gas mass is displayed by the remaining gas display device 13.

[0078] 8. Calculate the total mass m of gas in the full-capacity state of the gas cylinder using the results from the volume selection device 10 and the gas selection device 11. 总 .

[0079] 9. Through the gas mass m and the total gas mass m 总 Judged by percentage:

[0080] 1) m / m 总 ≥40%, warning light 14 turns green, indicating normal status.

[0081] 2) 40% ≥ m / m 总 ≥10%, warning light 14 turns yellow, indicating a warning status.

[0082] 3) 10% ≥ m / m 总 Warning light 14 is red, indicating an alarm status.

[0083] By using the gas law and a pressure reducing device to measure the current pressure, temperature, and filling volume of the gas cylinder, and combining this with the type of gas filled in the cylinder, the mass percentage of the remaining gas relative to the total cylinder volume is obtained. This mass percentage serves as the basis for displaying the remaining gas content in the cylinder. The measurement method is simple and easy to implement, enabling cylinder users to quickly determine the gas usage status and reduce the impact of not refilling due to low gas content.

[0084] Current technology cannot directly measure the remaining gas content in a gas cylinder. It usually relies on human experience to determine whether the gas content is insufficient and needs to be refilled when the cylinder pressure is below a certain value based on different gas types. However, gas is easily affected by temperature, and gas cylinders are filled by compression. After compression, the gas may liquefy or dissolve in the solvent inside the cylinder, making the specific situation complex. While using mass percentage to display the remaining gas in a gas cylinder may not be able to cover all gas cylinder usage scenarios, it is more intuitive and comprehensive than current technology and does not rely on human experience.

[0085] The required pressure and temperature can be measured using a simple device, such as a pressure regulator (pressure reducing valve) used on gas cylinders, which is capable of measuring the pressure before and after the valve. The temperature measuring device can use a common temperature sensor.

[0086] The cylinder volume and gas type can also be pre-stored, making the device simple in structure and low in cost. The computing unit can be a processor, and standard data such as the molar mass, critical temperature, and critical pressure corresponding to several common cylinder capacity specifications and gas types can be pre-stored on the memory connected to the processor, thus forming a volume selection device and a gas selection device.

[0087] 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 pressure-reducing device for measuring the residual gas content in a gas cylinder, characterized in that: include: A pressure reducer and a temperature measuring device are connected to the gas delivery pipe. The pressure reducer and the temperature measuring device are respectively connected to the calculation unit. The calculation unit is connected to the volume selection device, the gas selection device and the remaining gas display device. The computing unit is configured as follows: The gas pressure P and temperature T inside the gas cylinder are obtained from the pressure reducer and temperature measuring device, the gas cylinder volume V is selected by the volume selection device, and the gas type inside the gas cylinder is selected by the gas selection device. The gas in the cylinder is determined to be either in a gaseous state or a gas-liquid mixture state based on the relationship between the temperature and the critical temperature of the selected gas under pressure P. Based on the equation of state corresponding to the gas in a gaseous or gas-liquid mixed state, the amount of substance M of the remaining gas is obtained. Using the selected gas type and the mass of the gas when the gas cylinder is full, the mass percentage of the remaining gas relative to the total gas cylinder capacity is obtained and sent to the remaining gas display device. When the percentage meets the set threshold, an alert signal is issued.

2. The pressure reducing device for measuring the residual gas content in a gas cylinder as described in claim 1, characterized in that: When the gas is in the gaseous state, the amount of substance of the remaining gas is obtained using the real gas law. When the gas is in a gas-liquid mixture, the amount of substance of the remaining gas is obtained using the following formula: in: ; ； The gas pressure obtained through the pressure reducer; This represents the molar volume of the gas. For temperature; It is the critical temperature; The critical pressure; For comparison temperature; It is the eccentricity factor.

3. The pressure reducing device for measuring the residual gas content in a gas cylinder as described in claim 2, characterized in that: The mass of the remaining gas is obtained by using the amount of substance of the remaining gas and the molar mass corresponding to the gas type.

4. The pressure reducing device for measuring the residual gas content in a gas cylinder as described in claim 3, characterized in that: Based on the selected gas type and cylinder volume, the mass of the gas when the cylinder is full is obtained. Using the mass of the remaining gas, the percentage of the remaining gas relative to the total cylinder capacity is calculated.

5. The pressure reducing device for measuring the residual gas content in a gas cylinder as described in claim 1, characterized in that: The pressure reducer is connected to a flow regulating valve, a high-pressure display device, and a low-pressure display device. The high-pressure display device and the low-pressure display device measure and display the pressure inside the gas cylinder and the pressure after pressure reduction, respectively.

6. The pressure reducing device for measuring the residual gas content in a gas cylinder as described in claim 1, characterized in that: The two ends of the air duct are an air inlet and an air outlet, respectively. The pressure reducer is located near the air inlet, and the temperature measuring device is located near the air outlet. The temperature measuring device is connected to the temperature display device.

7. The pressure reducing device for measuring the residual gas content in a gas cylinder as described in claim 1, characterized in that: The pressure and temperature data acquired by the pressure reducer and temperature measuring device are sent to the computing unit via a data transmission line.

8. The pressure reducing device for measuring the residual gas content in a gas cylinder as described in claim 1, characterized in that: The volume selection device selects the corresponding gas cylinder capacity according to the usage requirements, sends it to the calculation unit, and displays it on the volume selection device.

9. The pressure reducing device for measuring the residual gas content in a gas cylinder as described in claim 1, characterized in that: The gas selection device selects the corresponding gas type according to the usage requirements, sends the information to the computing unit, and displays it on the gas selection device.

10. The pressure reducing device for measuring the residual gas content in a gas cylinder as described in claim 1, characterized in that: The remaining gas display device is equipped with an alarm light. It receives the result from the calculation unit, displays the percentage of remaining gas, and issues a reminder signal through the alarm light according to the set threshold.

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