Single-column, double-tube, double-outlet LNG flowmeter gas filling system and gas filling method

Abstract

The present invention discloses a single-column dual-tube dual-outlet LNG flowmeter gas filling system and gas filling method. The housing of the flowmeter has a first metering tube and a second metering tube arranged in parallel. The flowmeter is connected to the liquid phase space of the storage tank through the liquid inlet of the liquid inlet pipeline. LNG is connected to the input end of the flowmeter through the liquid inlet and the liquid inlet pipeline. The output end of the flowmeter is respectively connected to the first liquid filling pipeline and the second liquid filling pipeline. After being measured by the first metering tube and the second metering tube, the LNG flows out from the output end of the flowmeter and then passes through the corresponding first liquid filling pipeline and the second liquid filling pipeline to complete the filling of the gas cylinder of the external vehicle. In this way, the single-column dual-tube dual-outlet LNG flowmeter gas filling system and gas filling method of the present invention can achieve the purpose of simultaneous metering of the two metering channels inside the housing of a single flowmeter, and can be applied to LNG double-gun gas dispensers to complete the simultaneous filling and metering settlement of two vehicles.

Description

Technical Field

[0001] The present invention relates to the technical field of LNG filling, and in particular to a single-column double-tube double-outlet LNG flowmeter filling system and a filling method. Background Art

[0002] For LNG filling stations, if you want to improve the filling efficiency of the entire station by using a dual-lance gas dispenser, the current method is to install two single-meter flow meters inside the gas dispenser. This dual-lance gas dispenser is large and expensive, and because the gas dispenser has many internal components, its maintenance and replacement costs are also high.

[0003] At present, a single flow meter of a gas filling machine can only be connected to one gas gun to refuel a vehicle. If you want to improve the refueling efficiency of the gas station, you will consider adding a sufficient number of gas filling machines at the beginning of the design. Each gas filling machine with a single metering flow meter needs to be equipped with an independent valve and instrument operating system.

[0004] To facilitate the free entry and exit of vehicles in the gas station, each gas dispenser must have a certain safe driving distance. Therefore, a gas dispenser with a single flow meter will lead to an increase in the size of the gas station, which results in a waste of land resources.

[0005] In order to save land and reduce equipment costs, the current method is to install two single-metering flow meters inside a gas dispenser. In this way, a gas dispenser will have two gas guns to refuel vehicles. This type of dual-gun gas dispenser is large in size and high in cost. In addition, because there are many valves, instruments and other components inside the gas dispenser, some valves and instruments cannot be shared, and the cost of maintenance and replacement is also high. Summary of the Invention

[0006] The main technical problem solved by the present invention is to provide a single-column, dual-tube, dual-outlet LNG flowmeter filling system and filling method. Two flow tubes are placed in a flowmeter housing, with two metering channels, which can achieve the purpose of simultaneous metering in the two metering channels inside a single flowmeter housing. It can be applied to LNG dual-gun gas dispensers to complete simultaneous filling and metering settlement of two vehicles.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a single-column double-tube double-outlet LNG flowmeter gas filling system, including: a flowmeter, a liquid inlet pipeline, a first liquid filling pipeline and a second liquid filling pipeline.

[0008] The flow meter is connected to the liquid phase space of the storage tank through the liquid inlet of the liquid inlet pipeline. The LNG is connected to the input end of the flow meter through the liquid inlet and the liquid inlet pipeline. The output end of the flow meter is connected to the first liquid adding pipeline and the second liquid adding pipeline respectively.

[0009] The flow meter shell has a first metering tube and a second metering tube arranged in parallel. After being measured by the first metering tube and the second metering tube, the LNG flows out from the output end of the flow meter, and then passes through the corresponding first liquid filling pipeline and the second liquid filling pipeline to complete the filling of the gas cylinder of the external vehicle.

[0010] In a preferred embodiment of the present invention, the output end of the first liquid adding pipeline has a first liquid adding port, the first liquid adding port is connected to a first liquid adding gun, the output end of the second liquid adding pipeline has a second liquid adding port, the second liquid adding port is connected to a second liquid adding gun, and the first liquid adding gun and the second liquid adding gun are respectively connected to the corresponding gas cylinders of the external vehicle.

[0011] In a preferred embodiment of the present invention, a first liquid adding pneumatic valve and a first liquid adding filter are sequentially provided on the first liquid adding pipeline between the first metering tube and the first liquid adding port, and a first liquid adding check valve is provided in parallel between the input end of the first liquid adding pneumatic valve and the output end of the first liquid adding filter;

[0012] A second liquid adding pneumatic valve and a second liquid adding filter are sequentially arranged on the second liquid outlet pipeline between the second metering tube and the second liquid adding port, and a second liquid adding one-way valve is connected in parallel between the input end of the second liquid adding pneumatic valve and the output end of the second liquid adding filter.

[0013] In a preferred embodiment of the present invention, it also includes a return pipeline and a return liquid port, and a return liquid pneumatic valve and a return liquid check valve are provided on the return pipeline. The LNG liquid inside the housing of the flowmeter is connected to the liquid phase space of the storage tank through the return liquid pneumatic valve and the return liquid check valve.

[0014] In a preferred embodiment of the present invention, the first air return port, the first air return line, the second air return port and the second air return line are also included.

[0015] The first air return port is connected to the liquid return port through a first air return line. The first air return line is provided with a first breakaway valve, a first air return filter and a first air return check valve. After the first air return port is connected to the corresponding gas cylinder, the high-pressure gas passes through the first breakaway valve, the first air return filter and the first air return check valve in sequence, and then enters the gas phase space of the storage tank through the liquid return port;

[0016] The second air return port is connected to the liquid return port through the second air return pipeline, and the second air return pipeline is provided with a second break valve, a second air return filter and a second air return one-way valve. After the second air return port is connected to the corresponding gas cylinder, the high-pressure gas passes through the second break valve, the second air return filter and the second air return one-way valve in sequence, and enters the gas phase space of the storage tank through the liquid return port.

[0017] In a preferred embodiment of the present invention, it also includes a return air seat, the input end of the return air seat is connected to the first liquid adding port and the second liquid adding port respectively, and the output end of the return air seat passes through the third return air check valve and the return liquid check valve and then enters the liquid phase space of the storage tank through the return liquid port.

[0018] In a preferred embodiment of the present invention, it also includes a safety relief pipeline and a vent. The safety relief pipeline is directly connected to the gas phase space inside the shell of the flowmeter. A first stop valve and a safety valve are provided on the safety relief pipeline. A second stop valve is connected in parallel between the input end of the first stop valve and the output end of the safety valve.

[0019] In a preferred embodiment of the present invention, a differential pressure flow transmitter for measuring the differential pressure of the LNG flowing into the flow meter is provided on the housing of the flow meter; a first differential pressure transmitter for measuring the differential pressure of the LNG flowing through the first metering pipe is provided on the first metering pipe; a second differential pressure transmitter for measuring the differential pressure of the LNG flowing through the second metering pipe is provided on the second metering pipe; a temperature transmitter for temperature compensation of the LNG is also provided on the liquid inlet pipeline; and a pressure transmitter is also connected to the pipeline between the output end of the flow meter housing and the return liquid pneumatic valve.

[0020] In a preferred embodiment of the present invention, an integrator is further included, and the differential pressure flow transmitter, the first differential pressure transmitter, the second differential pressure transmitter, the temperature transmitter and the pressure transmitter are all electrically connected to the integrator.

[0021] To solve the above technical problems, another technical solution adopted by the present invention is to provide a liquid filling method for a single-column dual-tube dual-outlet LNG flowmeter, characterized in that it includes the above-mentioned single-column dual-tube dual-outlet LNG flowmeter gas filling system, and the steps are as follows:

[0022] a. Connect the first liquid filling port to the corresponding external vehicle gas cylinder through the first liquid filling gun, and connect the second liquid filling port to the corresponding external vehicle gas cylinder through the second liquid filling gun;

[0023] b. After the LNG inside the storage tank enters the flow meter housing through the liquid inlet, the temperature transmitter and pressure transmitter will monitor the temperature and pressure changes of the LNG liquid in the flow meter housing in real time, and the density value of the LNG will be measured by the density compensation differential pressure measuring device connected to the differential pressure flow transmitter;

[0024] When the LNG medium flows through the first metering pipe and the second metering pipe, the differential pressure values ​​on both sides of the first metering pipe and the second metering pipe are measured respectively by the first differential pressure transmitter and the second differential pressure transmitter, and the volume flow rate values ​​of the gas added to the first metering pipe and the second metering pipe are calculated respectively according to the relationship between the differential pressure and the flow rate;

[0025] c. When the first filling port is connected to the corresponding external vehicle's gas cylinder for filling, the first filling pneumatic valve opens, the return pneumatic valve closes, and the first filling filter filters out impurities, particles and other harmful substances in the LNG liquid. After filling is completed, the first filling pneumatic valve automatically closes, and the LNG liquid remaining in the first filling pneumatic valve and the first filling port hose returns to the flow meter housing through the first filling check valve;

[0026] When the second liquid filling port is connected to the corresponding external vehicle's gas cylinder for filling, the second liquid filling pneumatic valve opens, the liquid return pneumatic valve closes, and the second liquid filling filter filters out impurities, particles and other harmful substances in the LNG liquid. After the filling is completed, the second liquid filling pneumatic valve automatically closes, and the LNG liquid remaining in the second liquid filling pneumatic valve and the second liquid filling port hose returns to the housing of the flow meter through the second liquid filling check valve;

[0027] d. Close the first and second liquid-adding pneumatic valves, open the liquid-return pneumatic valve, and the LNG liquid inside the flowmeter housing returns to the storage tank after passing through the liquid-return pneumatic valve and the liquid-return check valve;

[0028] f. Connect the gas cylinder connected to the first liquid filling port to the first air return port of the gas filling system. After the first air return port is connected to the gas cylinder, the high-pressure gas passes through the first breakaway valve, the first air return filter, and the first one-way valve, and then enters the storage tank through the liquid return port;

[0029] Connect the gas cylinder connected to the second liquid filling port to the second gas return port of the gas filling system. When the second gas return port is connected to the gas cylinder, the high-pressure gas passes through the second breakaway valve, the second gas return filter and the second one-way valve, and then enters the storage tank through the liquid return port.

[0030] When the gas return seat is connected to the first liquid filling port and the second liquid filling port respectively, the liquid inside the flow meter housing passes through the third gas return check valve and the liquid return check valve, and then enters the storage tank through the liquid return port, completing the cycle debugging of the first liquid filling port and the second liquid filling port for LNG gas metering;

[0031] g. Connect the vent directly to the gas phase space inside the flow meter shell through a safety relief pipeline. When the pressure inside the flow meter shell exceeds the design pressure, the safety valve automatically opens and releases the pressure. When the pressure inside the shell is lower than the design pressure, the safety valve automatically closes.

[0032] The first stop valve is always in the lead-sealed open state and is used to close the pipeline during regular calibration of the safety valve; the second stop valve needs to be in the lead-sealed closed state under normal circumstances to quickly release the pressure in the shell.

[0033] The beneficial effects of the present invention are as follows: the single-column, dual-tube, dual-outlet LNG flowmeter filling system and filling method of the present invention place two flow tubes in a flowmeter housing, and have two metering channels, which can achieve the purpose of simultaneous metering in the dual metering channels inside a single flowmeter housing, and can be applied to LNG dual-gun gas filling machines to complete the simultaneous filling and metering settlement of two vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0035] Figure 1 This is a structural diagram of a single-column, double-tube, double-outlet LNG flowmeter gas filling system according to the present invention;

[0036] Figure 2 This is a structural diagram of the gas filling principle of the single-column, double-tube, double-outlet LNG flowmeter gas filling system of the present invention;

[0037] The components in the drawings are marked as follows: 100, flow meter, 110, first metering tube, 120, second metering tube, 130, liquid inlet line, 140, liquid inlet,

[0038] 210, first liquid adding pipeline, 211, first liquid adding pneumatic valve, 212, first liquid adding filter, 213, first liquid adding check valve, 214, first liquid adding port,

[0039] 220, second liquid adding pipeline, 221, second liquid adding pneumatic valve, 222, second liquid adding filter, 223, second liquid adding one-way valve, 224, second liquid adding port,

[0040] 230, return line, 231, return liquid pneumatic valve, 232, return liquid check valve, 233, return liquid port,

[0041] 240. First return air line, 241. First return air port, 242. First breakaway valve, 243. First return air filter, 244. First return air check valve,

[0042] 250, second return air line, 251, second return air port, 252, second breakaway valve, 253, second return air filter, 254, second return air check valve,

[0043] 260, return air seat, 261, third return air check valve, 270, safety release pipeline, 271, first stop valve, 272, safety valve, 273, second stop valve, 274, vent,

[0044] 300, differential pressure flow transmitter, 400, first differential pressure transmitter, 500, second differential pressure transmitter, 600, temperature transmitter, 700, pressure transmitter. DETAILED DESCRIPTION

[0045] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] See also Figures 1 to 2 , embodiments of the present invention include: Example 1:

[0047] A single-column, dual-tube, dual-outlet LNG flowmeter refueling system includes: a flowmeter 100, a liquid inlet pipeline 130, a first liquid refueling pipeline 210, and a second liquid refueling pipeline 220. The flowmeter 100 is connected to the liquid phase space of the storage tank via a liquid inlet 140 of the liquid inlet pipeline 130. LNG is connected to the input end of the flowmeter 100 via the liquid inlet 140 and the liquid inlet pipeline 130. The output end of the flowmeter 100 is connected to the first liquid refueling pipeline 210 and the second liquid refueling pipeline 220, respectively.

[0048] The output end of the first liquid adding pipeline 210 has a first liquid adding port 214, which is connected to a first liquid adding gun. The output end of the second liquid adding pipeline 220 has a second liquid adding port 224, which is connected to a second liquid adding gun. The first liquid adding gun and the second liquid adding gun are respectively connected to the gas cylinders of corresponding external vehicles.

[0049] The shell of the flow meter 100 has a first metering tube 110 and a second metering tube 120 arranged in parallel. After the LNG is measured by the first metering tube 110 and the second metering tube 120 respectively, it flows out from the output end of the flow meter and then passes through the corresponding first liquid filling pipeline 210 and the second liquid filling pipeline 220 to complete the filling of the gas cylinder of the external vehicle.

[0050] Furthermore, a temperature transmitter 600 for temperature compensation of LNG is provided on the liquid inlet pipeline 130, and a pressure transmitter 700 is connected to the output end of the flow meter 100 housing. The temperature transmitter 600 and the pressure transmitter 700 will monitor the temperature and pressure changes of the LNG liquid in the flow meter 100 housing in real time.

[0051] The housing of the flow meter 100 is provided with a differential pressure flow transmitter 300 for measuring the differential pressure of the LNG flowing into the flow meter. The density value of the LNG can be obtained by connecting the differential pressure flow transmitter 300 to a density compensation differential pressure measuring device, thereby completing the density compensation of the internal LNG.

[0052] The first metering pipe 110 is provided with a first differential pressure transmitter 400 for measuring the differential pressure of the LNG flowing through the first metering pipe 110 , and the second metering pipe 120 is provided with a second differential pressure transmitter 500 for measuring the differential pressure of the LNG flowing through the second metering pipe.

[0053] The first metering tube 110 and the second metering tube 120 both use Venturi tubes. According to the Bernoulli equation and the flow continuity equation, when the LNG medium flows through the first metering tube 110 and the second metering tube 120, a pressure difference is generated on both sides thereof. The differential pressure value is measured by the first differential pressure transmitter 400 and the second differential pressure transmitter 500, and the volume flow value of the gas filling is obtained from the relationship between the differential pressure and the flow rate.

[0054] The system also includes an integrator, to which the differential pressure flow transmitter 300, the first differential pressure transmitter 400, the second differential pressure transmitter 500, the temperature transmitter 600, and the pressure transmitter 700 are all electrically connected. The integrator is preferably a Flowcom 3000 integrator, and the signal input and calculation processes of all transmitters are performed by the Flowcom 3000 integrator, an electrical control element.

[0055] Specifically, a first liquid adding pneumatic valve 211 and a first liquid adding filter 212 are sequentially provided on the first liquid adding pipeline 210 between the first metering tube 110 and the first liquid adding port 214, and a first liquid adding check valve 213 is provided in parallel between the input end of the first liquid adding pneumatic valve 211 and the output end of the first liquid adding filter 212;

[0056] A second liquid adding pneumatic valve 221 and a second liquid adding filter 222 are sequentially arranged on the second liquid outlet pipeline 220 between the second metering tube 120 and the second liquid adding port 224 , and a second liquid adding one-way valve 223 is connected in parallel between the input end of the second liquid adding pneumatic valve 221 and the output end of the second liquid adding filter 222 .

[0057] The present invention places two flow tubes in a flow meter housing, which has two metering channels, and can achieve the purpose of simultaneous metering in the two metering channels inside a single flow meter housing.

[0058] It also includes a return pipeline 230 and a return liquid port 233. The return pipeline 230 is provided with a return liquid pneumatic valve 231 and a return liquid check valve 232. The LNG liquid inside the shell of the flow meter 100 is connected to the liquid phase space of the storage tank through the return liquid pneumatic valve 231 and the return liquid check valve 232.

[0059] It also includes a first air return port 241, a first air return line 240, a second air return port 251 and a second air return line 250.

[0060] The first gas return port 241 is connected to the liquid return port 233 through the first gas return line 240. The first gas return line 240 is provided with a first break valve 242, a first gas return filter 243, and a first gas return check valve 244. After the first gas return port 241 is connected to the corresponding gas cylinder, the high-pressure gas passes through the first break valve 242, the first gas return filter 243, and the first gas return check valve 244 in sequence, and then enters the gas phase space of the storage tank through the liquid return port 233.

[0061] The second air return port 251 is connected to the liquid return port 233 through the second air return pipeline 250. The second air return pipeline 250 is provided with a second break valve 252, a second air return filter 253 and a second air return check valve 254. After the second air return port 251 is connected to the corresponding gas cylinder, the high-pressure gas passes through the second break valve 252, the second air return filter 253 and the second air return check valve 254 in sequence, and then enters the gas phase space of the storage tank through the liquid return port 233.

[0062] The system further includes an air return seat 260 , the input ends of which are connected to the first liquid filling port 214 and the second liquid filling port 224 , respectively, to complete the liquid filling and debugging of the first metering tube 110 and the second metering tube 120 until the use requirements are met.

[0063] The output end of the gas return seat 260 passes through the third gas return one-way valve 261 and the liquid return one-way valve 232 and then enters the liquid phase space of the storage tank through the liquid return port 233.

[0064] It also includes a safety relief pipeline 270 and a vent 274. The safety relief pipeline 270 is directly connected to the gas phase space inside the shell of the flow meter 100. A first stop valve 271 and a safety valve 272 are provided on the safety relief pipeline 270. A second stop valve 273 is connected in parallel between the input end of the first stop valve 271 and the output end of the safety valve 272. Example 2:

[0065] A method for adding liquid to a single-column, dual-tube, dual-outlet LNG flowmeter includes the single-column, dual-tube, dual-outlet LNG flowmeter gas filling system of Example 1. The specific process is as follows:

[0066] Aeration process:

[0067] Connect the first liquid filling port 214 to the corresponding external vehicle gas cylinder through the first liquid filling gun, and connect the second liquid filling port 224 to the corresponding external vehicle gas cylinder through the second liquid filling gun.

[0068] After the LNG inside the storage tank enters the housing of the flow meter 100 through the liquid inlet 140, the temperature transmitter 600 and the pressure transmitter 700 will monitor the temperature and pressure changes of the LNG liquid in the flow meter housing 100 in real time, and the density value of the LNG will be measured by the density compensation differential pressure measurement device connected to the differential pressure flow transmitter 300;

[0069] When the LNG medium flows through the first metering pipe 110 and the second metering pipe 120, the differential pressure values ​​on both sides of the first metering pipe 110 and the second metering pipe 120 are respectively measured by the first differential pressure transmitter 400 and the second differential pressure transmitter 500. The volume flow rate values ​​of the gas added to the first metering pipe 110 and the second metering pipe 120 are respectively calculated based on the relationship between the differential pressure and the flow rate.

[0070] When the first liquid filling port 214 is connected to the corresponding external vehicle's gas cylinder for filling, the first liquid filling pneumatic valve 211 is opened and the liquid return pneumatic valve 231 is closed. Since the gas cylinder has high requirements for the cleanliness of the LNG medium, the first liquid filling filter 212 filters out impurities, particles and other harmful substances in the LNG liquid. After the filling is completed, the first liquid filling pneumatic valve 211 is automatically closed, and the LNG liquid remaining in the first liquid filling pneumatic valve 211 and the first liquid filling port hose is returned to the housing of the flow meter 100 through the first liquid filling check valve 213;

[0071] When the second liquid filling port 224 is connected to the gas cylinder of the corresponding external vehicle for filling, the second liquid filling pneumatic valve 221 is opened and the liquid return pneumatic valve 231 is closed. Since the gas cylinder has high requirements for the cleanliness of the LNG medium, the second liquid filling filter 222 filters out impurities, particles and other harmful substances in the LNG liquid. After the filling is completed, the second liquid filling pneumatic valve 221 is automatically closed, and the LNG liquid remaining in the second liquid filling pneumatic valve 221 and the second liquid filling port hose is returned to the housing of the flow meter 100 through the second liquid filling check valve 223.

[0072] Liquid return process:

[0073] This is a process that returns the LNG liquid in the housing of the flow meter 100 to the storage tank through the return line 230. The purpose is to prevent the LNG liquid stored in the housing of the flow meter 100 from increasing in temperature due to a long period of time without adding liquid, which may cause changes in liquid density and housing pressure and affect measurement accuracy and safety of use.

[0074] Close the first liquid adding pneumatic valve 211 and the second liquid adding pneumatic valve 221, and open the liquid returning pneumatic valve 231, wherein the liquid returning pneumatic valve 231 on the return line 230 is opened when the first liquid adding pneumatic valve 211 and the second liquid adding pneumatic valve 221 are both closed.

[0075] The LNG liquid inside the shell of the flow meter 100 returns to the storage tank through the liquid return port 233 after passing through the liquid return pneumatic valve 231 and the liquid return one-way valve 232. All branch pipelines are equipped with one-way valves to prevent the liquid from flowing out only through the liquid return port 233.

[0076] Return air process:

[0077] When the LNG liquid in the cylinder is used up or left for a long time, the pressure inside the cylinder will increase. The filling of the cylinder is achieved through pressure difference. High pressure is not conducive to liquid filling. The return gas process is mainly to return the high-pressure LNG gas in the cylinder to the storage tank through the return gas pipeline, and reduce the pressure inside the cylinder.

[0078] When the first gas return port 241 is connected to the gas cylinder, the high-pressure gas passes through the first break valve 242, the first gas return filter 243 and the first one-way valve 244, and then enters the storage tank through the liquid return port 233;

[0079] When the second air return port 251 is connected to the gas cylinder, the high-pressure gas passes through the second break valve 252, the second air return filter 253 and the second one-way valve 254, and then enters the storage tank through the liquid return port 233;

[0080] After the input end of the gas return seat 260 is connected to the first liquid filling port 214 and the second liquid filling port 224 respectively, the LNG in the housing of the flow meter 100 passes through the third gas return check valve 261 and the liquid return check valve 232, and enters the liquid phase space of the storage tank through the liquid return port 233, completing the liquid filling and debugging of the first metering pipe 110 and the second metering pipe 120 respectively until the use requirements are met.

[0081] Due to the slow heat exchange between the housing of the flow meter 100 and the outside that occurs after long-term placement, BOG gas is formed, or some sudden external adverse factors may cause the pressure inside the flow meter housing to rise sharply, exceeding the design strength of the equipment and causing danger.

[0082] The venting process is mainly a process of automatically discharging gas after the pressure reaches the set requirement by setting a safety discharge valve in the gas phase space, which effectively protects the safety of personnel and equipment:

[0083] The vent port 274 is directly connected to the gas phase space inside the housing of the flow meter 100 through the safety relief line 270. When the pressure inside the housing of the flow meter 100 exceeds the design pressure, the safety valve 272 automatically opens and releases the pressure. When the pressure inside the housing is lower than the design pressure, the safety valve 272 automatically closes.

[0084] The first stop valve 271 must always be in the lead-sealed open state. Its function is to close the pipeline when the safety valve 272 is regularly calibrated. The second stop valve 273 is a manual discharge valve provided to quickly release the pressure in the shell. Under normal circumstances, it needs to be in the lead-sealed closed state.

[0085] The beneficial effects of the single-column, double-tube, double-outlet LNG flowmeter gas filling system and liquid filling method of the present invention are:

[0086] Two flow tubes are placed in a flow meter housing, with two metering channels, which can achieve the purpose of simultaneous metering in two metering channels inside a single flow meter housing. It can be applied to LNG dual-gun gas dispensers to complete simultaneous filling and metering settlement of two vehicles;

[0087] At the same time, the volume and weight of the double-gun gas dispenser are greatly reduced, and the initial investment cost and later maintenance cost of the gas dispenser can be reduced.

[0088] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A single-column, double-tube, double-outlet LNG flowmeter refueling system, characterized in that: include: Flow meter, liquid inlet pipeline, first liquid adding pipeline and second liquid adding pipeline, The flow meter is connected to the liquid phase space of the storage tank through the liquid inlet of the liquid inlet pipeline. The LNG is connected to the input end of the flow meter through the liquid inlet and the liquid inlet pipeline. The output end of the flow meter is connected to the first liquid adding pipeline and the second liquid adding pipeline respectively. The housing of the flow meter has a first metering tube and a second metering tube arranged in parallel. LNG is measured by the first metering tube and the second metering tube respectively and then flows out from the output end of the flow meter. Then, the LNG is added to the gas cylinder of the external vehicle through the corresponding first and second liquid filling pipelines respectively. The output end of the first liquid-adding pipeline has a first liquid-adding port connected to a first liquid-adding gun, and the output end of the second liquid-adding pipeline has a second liquid-adding port connected to a second liquid-adding gun, and the first liquid-adding gun and the second liquid-adding gun are respectively connected to corresponding gas cylinders of external vehicles; A first liquid adding pneumatic valve and a first liquid adding filter are sequentially provided on the first liquid adding pipeline between the first metering tube and the first liquid adding port, and a first liquid adding check valve is provided in parallel between the input end of the first liquid adding pneumatic valve and the output end of the first liquid adding filter; A second liquid adding pneumatic valve and a second liquid adding filter are sequentially provided on the second liquid outlet pipeline between the second metering tube and the second liquid adding port, and a second liquid adding one-way valve is connected in parallel between the input end of the second liquid adding pneumatic valve and the output end of the second liquid adding filter; It also includes a return line and a liquid return port. The return line is provided with a liquid return pneumatic valve and a liquid return check valve. The LNG liquid inside the housing of the flowmeter is connected to the liquid phase space of the storage tank through the liquid return pneumatic valve and the liquid return check valve. It also includes a first air return port, a first air return line, a second air return port and a second air return line, The first air return port is connected to the liquid return port through a first air return line. The first air return line is provided with a first breakaway valve, a first air return filter and a first air return check valve. After the first air return port is connected to the corresponding gas cylinder, the high-pressure gas passes through the first breakaway valve, the first air return filter and the first air return check valve in sequence, and then enters the gas phase space of the storage tank through the liquid return port; The second air return port is connected to the liquid return port through a second air return line. The second air return line is provided with a second breakaway valve, a second air return filter and a second air return check valve. After the second air return port is connected to the corresponding gas cylinder, the high-pressure gas passes through the second breakaway valve, the second air return filter and the second air return check valve in sequence, and then enters the gas phase space of the storage tank through the liquid return port; It also includes a return air seat, the input end of the return air seat is connected to the first liquid filling port and the second liquid filling port respectively, and the output end of the return air seat passes through the third return air one-way valve and the return liquid one-way valve and then enters the liquid phase space of the storage tank through the return liquid port.

2. The single-column, double-tube, double-outlet LNG flowmeter refueling system according to claim 1 is characterized in that: It also includes a safety release pipeline and a vent. The safety release pipeline is directly connected to the gas phase space inside the shell of the flowmeter. A first stop valve and a safety valve are provided on the safety release pipeline. A second stop valve is connected in parallel between the input end of the first stop valve and the output end of the safety valve.

3. The single-column, double-tube, double-outlet LNG flowmeter refueling system according to claim 2 is characterized in that: The flowmeter housing is provided with a differential pressure flow transmitter for measuring the differential pressure of the LNG flowing into the flowmeter; the first metering pipe is provided with a first differential pressure transmitter for measuring the differential pressure of the LNG flowing through the first metering pipe; the second metering pipe is provided with a second differential pressure transmitter for measuring the differential pressure of the LNG flowing through the second metering pipe; the liquid inlet pipeline is also provided with a temperature transmitter for temperature compensation of the LNG; and a pressure transmitter is also connected to the pipeline between the output end of the flowmeter housing and the return liquid pneumatic valve.

4. The single-column, double-tube, double-outlet LNG flowmeter refueling system according to claim 3 is characterized in that: It also includes an integrator, and the differential pressure flow transmitter, the first differential pressure transmitter, the second differential pressure transmitter, the temperature transmitter and the pressure transmitter are all electrically connected to the integrator.

5. A gas filling method for a single-column, double-tube, double-outlet LNG flowmeter gas filling system, characterized in that: The single-column, double-tube, double-outlet LNG flowmeter refueling system according to any one of claims 1 to 4 comprises the following steps: a. Connect the first liquid filling port to the corresponding external vehicle gas cylinder through the first liquid filling gun, and connect the second liquid filling port to the corresponding external vehicle gas cylinder through the second liquid filling gun; b. After the LNG inside the storage tank enters the flow meter housing through the liquid inlet, the temperature transmitter and pressure transmitter will monitor the temperature and pressure changes of the LNG liquid in the flow meter housing in real time, and the density value of the LNG will be measured by the density compensation differential pressure measuring device connected to the differential pressure flow transmitter; When the LNG medium flows through the first metering pipe and the second metering pipe, the differential pressure values ​​on both sides of the first metering pipe and the second metering pipe are measured respectively by the first differential pressure transmitter and the second differential pressure transmitter, and the volume flow rate values ​​of the gas added to the first metering pipe and the second metering pipe are calculated respectively according to the relationship between the differential pressure and the flow rate; c. When the first liquid filling port is connected to the corresponding external vehicle's gas cylinder for filling, the first liquid filling pneumatic valve opens, the liquid return pneumatic valve closes, and the first liquid filling filter filters out impurities in the LNG liquid. After the filling is completed, the first liquid filling pneumatic valve automatically closes, and the LNG liquid remaining in the first liquid filling pneumatic valve and the first liquid filling port hose returns to the flow meter housing through the first liquid filling check valve; When the second liquid filling port is connected to the corresponding external vehicle's gas cylinder for filling, the second liquid filling pneumatic valve opens, the liquid return pneumatic valve closes, and the second liquid filling filter filters out impurities in the LNG liquid. After the filling is completed, the second liquid filling pneumatic valve automatically closes, and the LNG liquid remaining in the second liquid filling pneumatic valve and the second liquid filling port hose returns to the flow meter housing through the second liquid filling check valve; d. Close the first and second liquid-adding pneumatic valves, open the liquid-return pneumatic valve, and the LNG liquid inside the flowmeter housing returns to the storage tank after passing through the liquid-return pneumatic valve and the liquid-return check valve; f. Connect the gas cylinder connected to the first liquid filling port to the first air return port of the gas filling system. After the first air return port is connected to the gas cylinder, the high-pressure gas passes through the first breakaway valve, the first air return filter, and the first one-way valve, and then enters the storage tank through the liquid return port; Connect the gas cylinder connected to the second liquid filling port to the second gas return port of the gas filling system. When the second gas return port is connected to the gas cylinder, the high-pressure gas passes through the second breakaway valve, the second gas return filter and the second one-way valve, and then enters the storage tank through the liquid return port. When the gas return seat is connected to the first liquid filling port and the second liquid filling port respectively, the liquid inside the flow meter housing passes through the third gas return check valve and the liquid return check valve, and then enters the storage tank through the liquid return port, completing the cycle debugging of the first liquid filling port and the second liquid filling port for LNG gas metering; g. Connect the vent directly to the gas phase space inside the flow meter shell through a safety relief pipeline. When the pressure inside the flow meter shell exceeds the design pressure, the safety valve automatically opens and releases the pressure. When the pressure inside the shell is lower than the design pressure, the safety valve automatically closes. The first stop valve is always in the lead-sealed open state and is used to close the pipeline during the regular calibration of the safety valve; The second stop valve needs to be in a lead-sealed closed state under normal circumstances to quickly release the pressure in the shell.

Images