Gas cylinder static evaporation rate detection device and method

Abstract

The present invention relates to a gas cylinder static evaporation rate detection device, comprising a temperature collector, a pressure collector, and an integrated tester. The temperature collector is connected to the inlet of the gas cylinder vent valve pipeline, and the pressure collector is connected to the outlet of the gas cylinder vent valve; the temperature collector and the pressure collector are both connected to the integrated tester through a signal cable; or the temperature collector and the pressure collector work separately, and the integrated tester is used to calculate the static evaporation rate of the gas cylinder. The present invention also relates to a gas cylinder static evaporation rate detection method. The present invention can measure the static evaporation rate of the gas cylinder quickly and accurately under normal working conditions without the need for working fluid replacement, and can improve the operability of the detection, reduce the detection cost, shorten the detection time, and improve the detection efficiency; the integrated tester is provided with multiple ports, which can realize multi-channel simultaneous detection and calculation, saving detection time.

Description

Technical Field

[0001] The invention relates to the field of container performance detection, and in particular to a gas cylinder static evaporation rate detection device and method. Background Art

[0002] Static evaporation rate is an important indicator to measure the cold-keeping performance of cryogenic insulated gas cylinders. According to GB / T 34347-2017 "Periodic Inspection and Evaluation of Cryogenic Insulated Gas Cylinders" and GB / T 18443.5-2010 "Performance Test Methods for Vacuum Insulated Cryogenic Equipment Part 5: Static Evaporation Rate Measurement", it takes at least 24 hours to test the static evaporation rate of each gas cylinder, not including a series of processes such as fluid replacement, static, and testing, which is time-consuming and power-consuming. Taking LNG buses as an example, the gas cylinders on the vehicle cannot be disassembled and assembled at will, resulting in the weighing method being unsuitable for this inspection, and the flow meter method requires a 4-5 day inspection cycle, which is too long for LNG gas cylinders on buses, and the data acquisition equipment is also cumbersome. Therefore, the inspection method specified in the current standard is not enough to meet the actual inspection status. Summary of the invention

[0003] In view of the technical problems existing in the prior art, the first object of the present invention is to provide a gas cylinder static evaporation rate detection device, which can quickly and accurately measure the static evaporation rate of the gas cylinder under normal working conditions and without the need for working fluid replacement.

[0004] The second object of the present invention is to provide a method for detecting the static evaporation rate of a gas cylinder, which is a pressure-boosting method. The method can avoid the replacement of working fluid, effectively shorten the detection time, and improve the detection efficiency.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A gas cylinder static evaporation rate detection device comprises a temperature collector, a pressure collector and an integrated tester, wherein the temperature collector is connected to the inlet of a gas cylinder vent valve pipeline, and the pressure collector is connected to the outlet of the gas cylinder vent valve; both the temperature collector and the pressure collector are connected to the integrated tester via a signal cable; or both the temperature collector and the pressure collector work independently, and the integrated tester is used to calculate the static evaporation rate of the gas cylinder.

[0007] Furthermore, the integrated tester includes a display panel and a plurality of adjustment keys.

[0008] Furthermore, the integrated tester is provided with multiple ports, and the multiple ports can be connected to multiple signal cables at the same time.

[0009] Furthermore, the integrated tester, the temperature collector, and the pressure collector are all connected to the signal cable via a quick connector.

[0010] Furthermore, the measuring range of the temperature collector is -200 to 150°C, the tolerance value is ±1°C, and the temperature collector is a temperature sensor or a thermocouple.

[0011] Furthermore, the pressure collector has a measuring range of 0 to 4 MPa and an accuracy of 0.01 MPa, and the pressure collector is a pressure sensor or a pressure gauge.

[0012] A method for detecting static evaporation rate of a gas cylinder comprises the following steps:

[0013] Step 1: Fill the gas cylinder with the test medium to the rated filling rate, and then leave the cylinder to stand until thermal equilibrium is reached;

[0014] Step 2: Measure the temperature at the inlet of the vent valve pipeline of the gas cylinder, and calculate the average temperature T' at the inlet of the vent valve pipeline;

[0015] Step 3: Weigh the gas cylinder to obtain the total mass m0 of the test medium in the initial state;

[0016] Step 4: Calculate the volume V of the gas phase space in the initial state according to the initial saturated state equation group gs and the volume V of the liquid phase space in the initial state ls , the initial saturated state equations are:

[0017]

[0018] in:

[0019] V--effective volume of the gas cylinder, m 3 ;

[0020] v gs --Specific volume of gas phase in the initial state, m 3 / Kg;

[0021] v ls --Specific volume of liquid phase in the initial state, m 3 / Kg;

[0022] Step 5: Naturally pressurize the gas cylinder for several hours, then shake the medium in the cylinder evenly, and measure the lowest pressure value at the outlet of the gas cylinder vent valve to obtain the final saturated pressure;

[0023] Step 6: Calculate the volume V of the gas phase space in the final state according to the final saturated state equation group gf and the volume V of the liquid phase space in the final state lf , the final saturated state equations are:

[0024]

[0025] in:

[0026] v gf --Specific volume of gas phase in the final state, m 3 / Kg;

[0027] v lf --Specific volume of liquid phase in the final state, m 3 / Kg;

[0028] Step 7: Calculate the heat leakage Q0 during the test cycle according to the heat leakage formula of the boost method. The heat leakage formula of the boost method is:

[0029] Q0=(h gf ·m gf -h gs ·m gs )+(h lf ·m lf -h ls ·m ls )

[0030] in:

[0031] h gs --Specific enthalpy of gas phase at initial state, KJ / Kg;

[0032] m gs --The mass of the gas phase in the initial state, Kg;

[0033] h ls --Specific enthalpy of liquid phase in initial state, KJ / Kg;

[0034] m ls --The mass of the liquid phase in the initial state, Kg;

[0035] h gf --Specific enthalpy of gas phase in final state, KJ / Kg;

[0036] m gf --The mass of the gas phase in the final state, Kg;

[0037] h lf --Specific enthalpy of the liquid phase in the final state, KJ / Kg;

[0038] m lf --The mass of the liquid phase in the final state, Kg;

[0039] Step 8: Calculate the heat leakage Q' after ambient temperature correction according to the heat leakage correction formula. The heat leakage correction formula is:

[0040]

[0041] in:

[0042] --Average temperature during the test period, K;

[0043] T s -- Initial temperature of the test cycle, K;

[0044] T f -- Final temperature of the test cycle, K;

[0045] --standard temperature, K;

[0046] Step 9: The heat leakage formula of the weighing method or flow meter method is: Q1 = m·c p ·(T'-T0)+m·H, according to Q'=Q1, calculate the mass m of evaporated liquid:

[0047]

[0048] in:

[0049] Q1--Heat leakage by weighing method / flow meter method, KJ;

[0050] C p --Specific heat capacity of gas at constant pressure at temperature T', KJ / (Kg·K);

[0051] T'--average temperature at the inlet of the vent valve pipeline, K;

[0052] T0--temperature of saturated liquid under standard atmospheric pressure, K;

[0053] H--Latent heat of vaporization of saturated liquid under standard atmospheric pressure, KJ / Kg;

[0054] Step 10: Calculate the daily static evaporation rate according to the daily static evaporation rate formula The daily static evaporation rate formula is:

[0055]

[0056] in:

[0057] ρ--density of saturated liquid under standard atmospheric pressure, Kg / m 3 ;

[0058] V--effective volume of the gas cylinder, m 3 ;

[0059] n--test time, h.

[0060] Furthermore, the total mass of the test medium in the initial state m0 = the mass of the liquid phase in the initial state m ls .

[0061] Furthermore, the time for naturally increasing the pressure of the gas cylinder is 6 to 12 hours.

[0062] In general, the present invention has the following advantages:

[0063] The present invention can enable the static evaporation rate of the gas cylinder to be measured quickly and accurately under normal working conditions without the need for working fluid replacement, thereby improving the operability of detection, reducing detection costs, shortening detection time, and improving detection efficiency; the integrated tester is provided with multiple ports, which can realize multi-channel simultaneous detection and calculation, saving detection time. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a structural schematic diagram of the present invention.

[0065] Figure 2 It is a top view of a gas cylinder of the present invention.

[0066] Among them: 1 is a temperature collector, 2 is a pressure collector, 3 is an integrated tester, 3-1 is a display panel, 3-2 is an adjustment key, 4 is a gas cylinder, 5 is a vent valve, and 6 is a signal cable. DETAILED DESCRIPTION

[0067] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0068] like Figure 1 and Figure 2 As shown, a static evaporation rate detection device for a gas cylinder includes a temperature collector, a pressure collector, and an integrated tester; the temperature collector is connected to the inlet of the gas cylinder vent valve pipeline, the temperature collector uses a temperature sensor or thermocouple with a range of -200 to 150°C and a tolerance of ±1°C, and the temperature collector is used to measure the temperature value at the inlet of the gas cylinder vent valve pipeline; the pressure collector is connected to the outlet of the gas cylinder vent valve, the pressure collector uses a pressure sensor or pressure gauge with a range of 0 to 4MPa and an accuracy of 0.01MPa, and the pressure collector is used to measure the pressure value at the outlet of the gas cylinder vent valve; the temperature collector The temperature collector and pressure collector have two working modes. The first working mode is: the temperature collector and the pressure collector are connected to the integrated tester through a signal cable, and the signal cable can directly transmit the temperature value collected by the temperature collector and the pressure value collected by the pressure collector to the integrated tester; the second working mode is: neither the temperature collector nor the pressure collector is connected to the integrated tester, the temperature collector and the pressure collector work independently, and then the temperature value collected by the temperature collector and the pressure value collected by the pressure collector are manually input into the integrated tester; the integrated tester is used to calculate the static evaporation rate of the gas cylinder.

[0069] like Figure 1As shown, the integrated tester includes a display panel and multiple adjustment keys, the adjustment keys are located under the display panel, the display panel can display multiple basic parameters, collected temperature values, collected pressure values, heat leakage and the static evaporation rate obtained, and the multiple adjustment keys can input and adjust the corresponding data accordingly; the integrated tester is also provided with multiple ports, the multiple ports can be connected to multiple signal cables at the same time, and multiple temperature collectors and pressure collectors are connected through multiple signal cables, and the temperature and pressure values ​​of multiple gas cylinders can be collected at the same time, realizing multi-channel simultaneous detection and calculation, saving detection time and improving detection efficiency. The integrated tester, temperature collector, and pressure collector are all connected to the signal cable through a quick connector. In this embodiment, the quick connector uses a BNC adapter.

[0070] When using this device to detect the static evaporation rate of a gas cylinder, the temperature collector and the pressure collector use the first working mode, that is, the temperature collector and the pressure collector are connected to the integrated tester through a signal cable, and then the temperature collector is connected to the inlet of the gas cylinder vent valve pipeline, the vent valve is kept open, and the other valves are closed, and the temperature at the inlet of the gas cylinder vent valve pipeline is measured, that is, the temperature at the inlet of the vent valve pipeline where the gas in the collection bottle flows into the vent valve pipeline, the temperature value at the inlet of the gas cylinder vent valve pipeline is recorded, and the temperature average value is calculated. Then connect the pressure collector to the outlet of the gas cylinder vent valve, keep the vent valve open, and close the other valves to allow the entire gas cylinder to be naturally pressurized for 6 to 12 hours. Because the pressure collector is connected to the outlet of the gas cylinder vent valve, the gas in the bottle cannot flow out, and the entire gas cylinder is sealed, so the pressure will increase during the static process. After 6 to 12 hours of static pressure increase, shake the medium in the bottle to make the test medium in the final saturated state. During this process, the pressure in the bottle will drop, and the minimum pressure value at the outlet of the gas cylinder vent valve is measured, that is, the minimum value after the pressure in the bottle drops is recorded. In this process, the average temperature value collected by the temperature collector and the minimum pressure value collected by the pressure collector can be transmitted to the integrated tester through the signal cable, and can be displayed on the display panel of the integrated tester. Then set multiple basic parameters on the integrated tester, and the final static evaporation rate can be obtained through a series of formula operations inside the integrated tester.

[0071] A method for detecting static evaporation rate of a gas cylinder comprises the following steps:

[0072] Step 1: Fill the gas cylinder with the test medium to the rated filling rate, and then leave the gas cylinder to stand until thermal equilibrium is reached. The test medium can be liquid nitrogen, liquefied natural gas or other media;

[0073] Step 2: Connect the temperature collector to the inlet of the gas cylinder vent valve pipeline, keep the vent valve open, and close the other valves, measure the temperature at the inlet of the gas cylinder vent valve pipeline, and calculate the average temperature T' at the inlet of the vent valve pipeline;

[0074] Step 3: Remove the temperature collector and weigh the gas cylinder. Subtract the cylinder’s own weight from the total weight of the cylinder to get the total mass m0 of the test medium in the cylinder, that is, the total mass m0 of the test medium in the initial state. When the cylinder reaches the rated filling rate, the gas phase space is very small, so the mass of the gas phase can be ignored. The total mass m0 of the test medium in the initial state is equal to the mass of the liquid phase in the initial state, that is: m0 = m ls in:

[0075] m0--Total mass of the test medium in the initial state, Kg;

[0076] m ls --The mass of the liquid phase in the initial state, Kg;

[0077] Step 4: In the initial state, the test medium in the bottle is in the initial saturated state under the standard atmospheric pressure. Knowing that the air pressure in the initial saturated state is the standard atmospheric pressure, the initial saturated state equation group can be obtained. The initial saturated state equation group is:

[0078]

[0079] in:

[0080] V--effective volume of the gas cylinder, m 3 ;

[0081] V gs --The volume of the gas phase space in the initial state, m 3 ;

[0082] V ls --The volume of the liquid phase space in the initial state, m 3 ;

[0083] v gs --Specific volume of gas phase in the initial state, m 3 / Kg;

[0084] v ls --Specific volume of liquid phase in the initial state, m 3 / Kg;

[0085] Knowing that the initial saturated air pressure is the standard atmospheric pressure, we can get v gs and v ls , and V and m0 are both known quantities. According to the initial saturation state equations, V can be calculated. gs and V ls;

[0086] Step 5: Connect the pressure collector to the outlet of the vent valve of the gas cylinder, keep the vent valve open, and close the other valves to allow the entire gas cylinder to be naturally pressurized for 6 to 12 hours. During the whole process, there is no loss of the test medium. Then shake the medium in the bottle to make the test medium in the final saturated state. During this process, the pressure in the bottle will drop. Measure the lowest pressure value at the outlet of the vent valve of the gas cylinder, that is, record the lowest value after the pressure in the bottle drops. This lowest value is the final saturated state pressure;

[0087] Step 6: Knowing the final saturation state pressure, we can get the final saturation state equations, which are:

[0088]

[0089] in:

[0090] V gf --The volume of the gas phase space in the final state, m 3 ;

[0091] V lf --The volume of the liquid phase space in the final state, m 3 ;

[0092] v gf --Specific volume of gas phase in the final state, m 3 / Kg;

[0093] v lf --Specific volume of liquid phase in the final state, m 3 / Kg;

[0094] Knowing the final saturation pressure, we can get v gf and v lf , and V and m0 are both known quantities. According to the final saturation state equations, V can be calculated. gf and V lf ;

[0095] Step 7: The method for measuring the static evaporation rate of the gas cylinder in the present invention is the boost method. The thermodynamic model of the boost method is a closed system. According to the energy balance equation of the thermodynamic closed system: total heat absorption = final state heat - initial state heat, the heat leakage formula of the boost method can be obtained. The heat leakage formula of the boost method is:

[0096] Q0=(h gf ·m gf -h gs ·m gs )+(h lf ·m lf -h ls ·mls )

[0097] in:

[0098] Q0--Heat leakage during the test cycle, KJ;

[0099] h gs --Specific enthalpy of gas phase at initial state, KJ / Kg;

[0100] m gs --The mass of the gas phase in the initial state, Kg;

[0101] h ls --Specific enthalpy of liquid phase in initial state, KJ / Kg;

[0102] m ls --The mass of the liquid phase in the initial state, Kg;

[0103] h gf --Specific enthalpy of gas phase in final state, KJ / Kg;

[0104] m gf --The mass of the gas phase in the final state, Kg;

[0105] h lf --Specific enthalpy of the liquid phase in the final state, KJ / Kg;

[0106] m lf --The mass of the liquid phase in the final state, Kg;

[0107] Knowing that the initial saturated pressure is the standard atmospheric pressure, we can get h gs and h ls ; Knowing the final saturation pressure, we can get h gf and h lf ; and V has been calculated in the fourth step gs and V ls , V has been calculated in step 6 gf and V lf , and v gs 、v ls 、v gf 、v lf All are known quantities. According to the specific volume v = volume V / mass m, m can be calculated. gs 、m ls 、m gf 、m lf , and then according to the heat leakage formula of the boost method, Q0 can be calculated;

[0108] Step 8: Since the heat transfer process is continuous and the measurement process is affected by the ambient temperature, it is necessary to correct the heat leakage. The heat leakage correction formula is:

[0109]

[0110] in:

[0111] Q'--heat leakage after ambient temperature correction, KJ;

[0112] --Average temperature during the test period, K;

[0113] T s -- Initial temperature of the test cycle, K;

[0114] T f -- Final temperature of the test cycle, K;

[0115] --standard temperature, K;

[0116] Q0 has been calculated in step 7, and T s , T f , All of them are known quantities, and Q' can be calculated according to the heat leakage correction formula;

[0117] Step 9: The traditional method of measuring the static evaporation rate of gas cylinders is the weighing method or flow meter. The thermodynamic model of the weighing method or flow meter is an open system. According to the energy balance equation of the thermodynamic open system: total heat absorption = liquid phase heat absorption + gas phase heat absorption, the heat leakage formula of the weighing method or flow meter method can be obtained. The heat leakage formula of the weighing method or flow meter method is:

[0118] Q1=m·c p ·(T'-T0)+m·H

[0119] in:

[0120] Q1--Heat leakage by weighing method / flow meter method, KJ;

[0121] m--mass of evaporated liquid, Kg;

[0122] C p --Specific heat capacity of gas at constant pressure at temperature T', KJ / (Kg·K);

[0123] T'--average temperature at the inlet of the vent valve pipeline, K;

[0124] T0--temperature of saturated liquid under standard atmospheric pressure, K;

[0125] H--Latent heat of vaporization of saturated liquid under standard atmospheric pressure, KJ / Kg;

[0126] Because the heat leakage of the closed system and the open system during the measurement process is almost equal, the heat leakage obtained by the boost method is equal to the heat leakage obtained by the weighing method or the flow meter method, that is, Q' = Q1; therefore:

[0127]

[0128] Q' has been calculated in step 8, and C p , T', T0, H are all known quantities, and m can be calculated according to the formula;

[0129] Step 10: Calculate the daily static evaporation rate. The daily static evaporation rate formula is:

[0130]

[0131] in:

[0132] --Daily static evaporation rate, expressed as percentage per day (% / d);

[0133] ρ--density of saturated liquid under standard atmospheric pressure, Kg / m 3 ;

[0134] V--effective volume of the gas cylinder, m 3 ;

[0135] n--test time, h;

[0136] In step 9, m has been calculated, and ρ, V, and n are all known quantities. According to the daily static evaporation rate formula, we can calculate

[0137] In the actual operation process, if the saturation pressure of the test medium is known, the corresponding saturation temperature, specific volume, enthalpy value, specific heat capacity, latent heat of vaporization and other physical parameters of the gas-liquid phase can be obtained by reading the graph, consulting the saturation physical parameter table, consulting the fluid medium data volume, etc., and then the daily static evaporation rate can be calculated through the above series of formulas. This embodiment forms a database with multiple physical parameters of the test medium, puts this database into an integrated tester, and then puts a series of formulas for calculating the daily static evaporation rate into the integrated tester to form an automatic solution system. When the measured data is input into the integrated tester, the integrated tester can perform automatic calculations to obtain the final result. If the temperature collector and the pressure collector are both connected to the integrated tester through a signal cable, the signal cable can directly transmit the collected average temperature T' and the final saturation state pressure at the inlet of the vent valve pipeline to the integrated tester, and the integrated tester can calculate the daily static evaporation rate. Alternatively, the temperature collector and the pressure collector are not connected to the integrated tester. The temperature collector and the pressure collector work separately. Then the average temperature T' and the final saturation pressure at the inlet of the vent valve pipeline collected are manually input into the integrated tester. The integrated tester can also calculate the daily static evaporation rate.

[0138] The present invention replaces the traditional open system test method (weighing method / flow meter method) with a closed system test method (boosting method), which is a new gas cylinder static evaporation rate detection method. The detection method can effectively shorten the detection time from the original at least 24 hours to only 6 to 12 hours, and can avoid the replacement of working fluids, thereby improving the detection level of the static evaporation rate of gas cylinders, and providing support and guarantee for the supervision and regular inspection of gas cylinder-related products.

[0139] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for detecting static evaporation rate of a gas cylinder, characterized in that: The following steps are involved: Step 1: Fill the gas cylinder with the test medium to the rated filling rate, and then leave the cylinder to stand until thermal equilibrium is reached; Step 2: Measure the temperature at the inlet of the vent valve pipeline of the gas cylinder, and calculate the average temperature T' at the inlet of the vent valve pipeline; Step 3: Weigh the gas cylinder to obtain the total mass m0 of the test medium in the initial state; Step 4: Calculate the volume V of the gas phase space in the initial state according to the initial saturated state equation group gs and the volume V of the liquid phase space in the initial state ls , the initial saturated state equations are: in: V--effective volume of the gas cylinder, m 3 ; v gs --Specific volume of gas phase in the initial state, m 3 / Kg; v ls --Specific volume of liquid phase in the initial state, m 3 / Kg; Step 5: Naturally pressurize the gas cylinder for several hours, then shake the medium in the cylinder evenly, and measure the lowest pressure value at the outlet of the gas cylinder vent valve to obtain the final saturated pressure; Step 6: Calculate the volume V of the gas phase space in the final state according to the final saturated state equation group gf and the volume V of the liquid phase space in the final state lf , the final saturated state equations are: in: v gf --Specific volume of gas phase in the final state, m 3 / Kg; v lf --Specific volume of liquid phase in the final state, m 3 / Kg; Step 7: Calculate the heat leakage Q0 during the test cycle according to the heat leakage formula of the boost method. The heat leakage formula of the boost method is: Q0=(h gf ·m gf -h gs ·m gs )+(h lf ·m lf -h ls ·m ls ) in: h gs --Specific enthalpy of gas phase at initial state, KJ / Kg; m gs --The mass of the gas phase in the initial state, Kg; h ls --Specific enthalpy of liquid phase in initial state, KJ / Kg; m ls --The mass of the liquid phase in the initial state, Kg; h gf --Specific enthalpy of gas phase in final state, KJ / Kg; m gf --The mass of the gas phase in the final state, Kg; h lf --Specific enthalpy of the liquid phase in the final state, KJ / Kg; m lf --The mass of the liquid phase in the final state, Kg; Step 8: Calculate the heat leakage Q' after ambient temperature correction according to the heat leakage correction formula. The heat leakage correction formula is: in: --Average temperature during the test period, K; T s -- Initial temperature of the test cycle, K; T f -- Final temperature of the test cycle, K; --standard temperature, K; Step 9: The heat leakage formula of the weighing method or flow meter method is: Q1 = m·c p ·(T'-T0)+m·H, according to Q'=Q1, calculate the mass m of evaporated liquid: in: Q1--Heat leakage by weighing method / flow meter method, KJ; C p --Specific heat capacity of gas at constant pressure at temperature T', KJ / (Kg·K); T'--average temperature at the inlet of the vent valve pipeline, K; T0--temperature of saturated liquid under standard atmospheric pressure, K; H--Latent heat of vaporization of saturated liquid under standard atmospheric pressure, KJ / Kg; Step 10: Calculate the daily static evaporation rate according to the daily static evaporation rate formula The daily static evaporation rate formula is: in: ρ--density of saturated liquid under standard atmospheric pressure, Kg / m 3 ; V--effective volume of the gas cylinder, m 3 ; n--test time, h.

2. A method for detecting static evaporation rate of a gas cylinder according to claim 1, characterized in that: The total mass of the test medium in the initial state m0 = the mass of the liquid phase in the initial state m ls .

3. A method for detecting static evaporation rate of a gas cylinder according to claim 1, characterized in that: The time for natural pressurization of the gas cylinder is 6 to 12 hours.

4. A method for detecting static evaporation rate of a gas cylinder according to any one of claims 1 to 3, characterized in that: The detection is performed using a gas cylinder static evaporation rate detection device, which includes a temperature collector, a pressure collector, and an integrated tester. The temperature collector is connected to the inlet of the gas cylinder vent valve pipeline, and the pressure collector is connected to the outlet of the gas cylinder vent valve; both the temperature collector and the pressure collector are connected to the integrated tester through a signal cable; or both the temperature collector and the pressure collector work separately, and the integrated tester is used to calculate the static evaporation rate of the gas cylinder.

5. A method for detecting static evaporation rate of a gas cylinder according to claim 4, characterized in that: The integrated tester includes a display panel and a plurality of adjustment keys.

6. A method for detecting static evaporation rate of a gas cylinder according to claim 4, characterized in that: The integrated tester is provided with multiple ports, and multiple signal cables can be connected to the multiple ports at the same time.

7. A method for detecting static evaporation rate of a gas cylinder according to claim 4, characterized in that: The integrated tester, temperature collector and pressure collector are all connected to the signal cable through quick connectors.

8. A method for detecting static evaporation rate of a gas cylinder according to claim 4, characterized in that: The measuring range of the temperature collector is -200~150℃, the tolerance value is ±1℃, and the temperature collector is a temperature sensor or a thermocouple.

9. A method for detecting static evaporation rate of a gas cylinder according to claim 4, characterized in that: The pressure collector has a measuring range of 0 to 4 MPa and an accuracy of 0.01 MPa. The pressure collector is a pressure sensor or a pressure gauge.

Images