Variable-viscosity working medium filling system and device and control method

Abstract

The invention relates to a variable-viscosity working medium filling system and device and a control method, the variable-viscosity working medium filling system is placed in a drying oven, the drying oven provides a temperature control environment for the filling device, and a vacuum pump set is used for vacuumizing a 2 # liquid storage tank, a 3 # liquid storage tank and a filling pipeline; the nitrogen source is used for compacting a container in the filled phase change energy storage device and blowing and cleaning a filling pipeline; the measurement and control device monitors the temperature and the vacuum degree of the drying oven, the capacity in each liquid storage tank and the flow of the working medium, controls opening and closing of each pneumatic valve and each electromagnetic valve according to a pre-compiled control time sequence, and performs filling by adopting a graded gradient method after the variable-viscosity working medium is liquefied.

Description

TECHNICAL FIELD

[0001] The application relates to a variable-viscosity working medium filling system, device and control method, and belongs to the technical field of mechanical engineering. BACKGROUND

[0002] With the increasing complexity and diversification of space missions, the thermal load of on-board single-machine devices is becoming increasingly large. Meanwhile, electronic devices for spacecraft tend to be small, efficient, light and compact, which results in a sharp increase in the heat consumption and heat flux density of single machines for spacecraft, greatly increasing the difficulty of heat dissipation and temperature control of the single machines. For large-heat-consumption single machines and transceiver assemblies that work intermittently, if conventional thermal control technology is used, the mass resources required for heat transport and dissipation channels are considerable, and the compensation power consumption during the non-working period of the single machine is also very high.

[0003] A phase change energy storage device absorbs and releases heat through the melting and solidification of a phase change material, and is often used in spacecraft with periodic changes in internal heat sources or external environments to maintain the relative stability of the temperature of instruments and equipment. In view of the extremely low thermal conductivity and weak heat transfer capacity of the phase change material itself, in recent years, the phase change material has been compounded with a high-thermal-conductivity material to improve its thermal conductivity. High-thermal-conductivity solvent-free carbon nanofluid is a kind of efficient thermal management material. Graphene, carbon nanotubes or carbon black are used as the core-shell structure of high-thermal-conductivity carbon nanomaterials. A flexible organic molecule outer layer is grafted by using surface in-situ acidification, surface grafting and ion exchange method. The carbon nanofluid is low in viscosity and flowable under the condition close to room temperature, has excellent thermal conductivity, a large specific surface area and strong adsorption, and has the advantages of large phase change latent heat, small density and light mass of the phase change material, and is suitable for solving the heat dissipation problem of short-time large-heat-consumption single machines.

[0004] The density of the carbon nanofluid is 1030ˉ1650 kg / m 3 , the specific heat capacity is about 103.5 kJ / kg, the phase change temperature is 30ˉ80℃, the thermal conductivity is 1ˉ40 W / (mK), the viscosity is 10 3 ˉ10 -2 Pa·s (-50ˉ200℃), and the thermal physical parameters of the carbon nanofluid are greatly different from the proportioning of each component. In view of the temperature control requirement of the short-time large-heat-consumption single machine, the carbon-based composite phase change device uses high-thermal-conductivity solvent-free carbon nanofluid material as the main energy storage and heat conduction carrier, uses high-thermal-conductivity expanded graphene to strengthen heat conduction, and uses the latent heat and large specific heat capacity of the nanofluid phase change material to realize the peak clipping and valley filling of heat, so that the temperature rise of the short-time large-heat-consumption single machine can be effectively inhibited, the compensation power consumption required during the non-working period of the single machine can be reduced, and the weight resources and power consumption resources of the satellite can be saved.

[0005] The carbon-based composite phase change device takes carbon nanometer fluid material as a core component, is composed of an upper cover plate, a lower shell and the carbon nanometer fluid material. All joint areas of the upper cover plate and the lower shell are welded through a diffusion process, mainly for packaging the carbon nanometer fluid, and meanwhile, a satellite structure plate and a satellite-borne printed board are combined for structure optimization design, so that the structure interface installation of the phase change energy storage device, the satellite structure plate and the satellite-borne single machine is realized, and the instantaneous large heat dissipation and temperature control requirements of the single machine are met. According to the differences of the filler and the matrix, the filling methods of the phase change energy storage material include vacuum melting pouring, mold powder pressing and porous solution immersion. The solid cold pressing filling has the advantages of low temperature operation, simple operation and low cost, but for irregular filling containers with microstructures, gaps and gases are left, which affects the filling rate and the heat conduction characteristics; the vacuum melting pouring method and the equipment are commonly used for filling the paraffin and n-dodecane working medium, and for filling the high-viscosity carbon nanometer fluid working medium, there are the defects that micro-bubbles of the working medium are difficult to completely remove, the complex cavity is not filled uniformly due to surface tension, and the filling rate control precision is insufficient. SUMMARY

[0006] The technical problem solved by the present application is to overcome the shortcomings of the prior art and provide a variable viscosity working medium filling system, device and control method for metering filling of carbon nanometer fluid working medium with a large viscosity range.

[0007] The technical solution of the present application is a variable viscosity working medium filling system, which comprises a filter, a first liquid storage tank, a second liquid storage tank, a third liquid storage tank, a first pneumatic valve, a second pneumatic valve, a third pneumatic valve, a first electromagnetic valve AF4, a first bidirectional electromagnetic valve AF5, a second bidirectional electromagnetic valve AF6, a second electromagnetic valve AF7, a third electromagnetic valve AF8, a fourth electromagnetic valve AF9, a flow control valve and a vacuum baffle valve.

[0008] The first liquid storage tank, the first pneumatic valve, the second liquid storage tank, the second pneumatic valve, the third liquid storage tank, the flow control valve and the third pneumatic valve are connected in sequence from top to bottom, and the third pneumatic valve is connected to a filling connector for connecting a phase change energy storage device to be filled.

[0009] The first electromagnetic valve is connected to a pipeline between the first pneumatic valve and the second liquid storage tank, the first bidirectional electromagnetic valve is connected to a pipeline between the second pneumatic valve and the third liquid storage tank, and the second bidirectional electromagnetic valve is connected to a pipeline between the flow control valve and the third pneumatic valve.

[0010] One end of the third electromagnetic valve is connected to a vacuum pump group in communication with the vacuum baffle valve, and the other end is connected to the first electromagnetic valve, the first bidirectional electromagnetic valve and the second bidirectional electromagnetic valve, for independently evacuating the filling pipelines.

[0011] The second electromagnetic valve is connected with the filter at one end and connected with the first electromagnetic valve, the first bidirectional electromagnetic valve and the second bidirectional electromagnetic valve at the other end, and is used for charging the tank line and is used for re-pressurizing each section of the charging pipeline.

[0012] The fourth electromagnetic valve is connected with the dry high-pressure gas source at one end and connected with the first electromagnetic valve, the first bidirectional electromagnetic valve and the second bidirectional electromagnetic valve at the other end, and is used for charging the tank line and is used for purging and cleaning the charging pipeline.

[0013] Preferably, the lowermost end of the phase-change working medium charging system is sealed and connected with the liquid filling pipe of the phase-change energy storage device to be charged through a sealing ring.

[0014] Preferably, the flow control valve and each pneumatic valve are compatible with the charging working medium.

[0015] Preferably, the liquid level gauge is arranged outside the liquid storage tank and is used for capacity measurement and calibration.

[0016] The second technical solution of the present application is a variable-viscosity working medium charging device, which comprises the above-mentioned variable-viscosity working medium charging system, an oven, a vacuum pump set, a measurement and control device and a nitrogen source.

[0017] The variable-viscosity working medium charging system is placed in the oven, the oven provides a temperature control environment for the charging device, the vacuum pump set is used for vacuumizing the second liquid storage tank, the third liquid storage tank and the charging pipeline, the nitrogen source is used for compacting the container in the phase-change energy storage device after charging and purging and cleaning the charging pipeline, and the measurement and control device monitors the oven temperature, the vacuum degree, the capacity of each liquid storage tank and the working medium charging flow, and controls the opening and closing of each pneumatic valve and electromagnetic valve according to a pre-programmed control time sequence.

[0018] The second technical solution of the present application is a variable-viscosity working medium charging device, which comprises the above-mentioned variable-viscosity working medium charging system, an oven, a vacuum pump set, a measurement and control device and a nitrogen source.

[0019] S1, injecting the working medium into the first liquid storage tank, and installing the phase-change energy storage device to be charged to the charging joint;

[0020] S2, turning on the oven and heating the whole device to a set temperature, so that the viscosity of the variable-viscosity working medium is greatly reduced;

[0021] S3, setting the initial state of all pneumatic valves and electromagnetic valves to the closed state;

[0022] S4, opening the vacuum pump, the vacuum block valve and the third electromagnetic valve;

[0023] S5, opening the first electromagnetic valve, and vacuumizing the second liquid storage tank and the connecting pipeline;

[0024] S6, the first electromagnetic valve is closed, the first pneumatic valve is opened, the working medium is filled into the second liquid storage tank, and the working medium in the second liquid storage tank reaches the first preset capacity, and the first pneumatic valve is closed;

[0025] S7, the first bidirectional electromagnetic valve is opened, the third liquid storage tank and the connecting pipeline are pumped into a vacuum state;

[0026] S8, the first bidirectional electromagnetic valve is closed, the second pneumatic valve is opened, the working medium is filled into the third liquid storage tank, and the working medium in the third liquid storage tank reaches the second preset capacity, and the second pneumatic valve is closed;

[0027] S9, the third pneumatic valve and the second bidirectional electromagnetic valve are opened, and the phase change energy storage device to be filled is pumped into a vacuum state;

[0028] S10, the third pneumatic valve and the second bidirectional electromagnetic valve are closed, the third electromagnetic valve is closed, the vacuum pump group is closed, and the flow control valve is opened, and the pipeline in front of the third pneumatic valve is filled with the working medium;

[0029] S11, the third pneumatic valve is opened, the working medium is filled into the phase change energy storage device to be filled, the flow control valve is used to detect and control the flow of the working medium, and the medium in the phase change energy storage device to be filled meets the preset liquid filling amount requirement;

[0030] S12, the fourth electromagnetic valve is opened, the dry high-pressure gas source switch is opened, and the pipeline is pressurized;

[0031] S13, the second bidirectional electromagnetic valve is opened, the high-pressure nitrogen gas is used to compact the working medium in the filling pipeline and the phase change energy storage device, and then the second bidirectional electromagnetic valve is closed;

[0032] S14, the third pneumatic valve is closed, the phase change energy storage device to be filled is taken down, weighed, and the weight change before and after weighing is compared, and the filling is completed.

[0033] Preferably, the first preset capacity is 1 / 2-2 / 3 of the volume of the second liquid storage tank, and the second preset capacity is 1 / 2-2 / 3 of the volume of the third liquid storage tank.

[0034] Preferably, the vacuum degree of the vacuum state is below 1 Pa.

[0035] Preferably, the filling flow of the variable-viscosity working medium is controlled by the pneumatic valve and the flow control valve, the filling rate is adjusted in the range of 10-50 mL / min, and the single filling deviation of the phase change working medium is not more than 2 mL.

[0036] Preferably, the variable-viscosity working medium is a carbon nano fluid working medium.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] (1) By pre-analyzing the physical properties of the working fluid at different temperatures, such as density, viscosity and thermal expansion, this invention sets filling process parameters such as vacuum degree, filling temperature and filling volume, which can realize microbubble removal, optimal filling rate control and batch continuous operation of high viscosity working fluid filling operation.

[0039] (2) The present invention uses an oven to heat up the filling system and the working fluid as a whole, thereby realizing the low viscosity flow and flow rate measurement of the high viscosity working fluid at high temperature.

[0040] (3) The high vacuum of the filling circuit of the present invention can effectively reduce the gas gap in the filling container and the gas residue in the working medium.

[0041] (4) The present invention uses a liquid level gauge for liquid storage tank measurement, liquid flow controller for regulation and weighing to achieve optimal filling rate control.

[0042] (5) The present invention proposes a graded gradient vacuum filling method, which effectively improves the problems of difficult elimination of microbubbles in the working fluid, uneven filling of complex microstructure cavities due to surface tension, and insufficient filling rate control accuracy in the filling of high viscosity carbon nanotube fluid working fluid compared with solid cold pressing filling and traditional vacuum melting injection method. Attached Figure Description

[0043] The accompanying drawings are provided to further illustrate the invention and form part of this application. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0044] Figure 1 This diagram illustrates the principle of a variable viscosity working fluid filling device according to an embodiment of the present invention.

[0045] Figure 2 This diagram illustrates the structural layout of the filling system according to an embodiment of the present invention.

[0046] Figure 3 This diagram illustrates the liquid storage tank according to an embodiment of the present invention.

[0047] Figure 4 This describes the development process of the filling device described in the embodiments of the present invention. Detailed Implementation

[0048] The present invention will be further described below with reference to the embodiments.

[0049] like Figure 1 As shown, the present invention provides a variable viscosity working fluid filling device, which includes two variable viscosity working fluid filling systems, an oven, a vacuum pump group, a measurement and control device, and a nitrogen source; the two variable viscosity working fluid filling systems are referred to as system A and system B, respectively.

[0050] The variable viscosity working medium filling system is placed in an oven, the oven provides a temperature control environment for the filling device, and a vacuum pump set is used for vacuumizing the 2# liquid storage tank, the 3# liquid storage tank and the filling pipeline; a nitrogen source is used for compacting the container in the phase change energy storage device after filling, and is used for blowing and cleaning the filling pipeline; and a measurement and control device monitors the oven temperature, the vacuum degree, the capacity in each liquid storage tank and the working medium flow, and controls the opening and closing of each pneumatic valve and electromagnetic valve according to a pre-programmed control time sequence.

[0051] The filter is shared by the A system and the B system, and the A system further comprises a 1# liquid storage tank, a 2# liquid storage tank, a 3# liquid storage tank, a pneumatic valve AF1, a pneumatic valve AF2, a pneumatic valve AF3, an electromagnetic valve AF4, a bidirectional electromagnetic valve AF5, a bidirectional electromagnetic valve AF6, an electromagnetic valve AF7, an electromagnetic valve AF8, an electromagnetic valve AF9, a flow control valve, a heating belt and a vacuum flashboard valve.

[0052] The 1# liquid storage tank, the pneumatic valve AF1, the 2# liquid storage tank, the pneumatic valve AF2, the 3# liquid storage tank, the flow control valve and the pneumatic valve AF3 are sequentially connected from top to bottom, the pneumatic valve AF3 is connected to a filling connector, and the filling connector is used for connecting a phase change energy storage device to be filled.

[0053] The electromagnetic valve AF4 is connected to a pipeline between the first pneumatic valve and the 2# liquid storage tank, the bidirectional electromagnetic valve AF5 is connected to a pipeline between the second pneumatic valve and the 3# liquid storage tank, and the bidirectional electromagnetic valve AF6 is connected to a pipeline between the flow control valve and the third pneumatic valve.

[0054] One end of the electromagnetic valve AF8 is connected to the vacuum flashboard valve connected to the vacuum pump set, and the other end of the electromagnetic valve AF8 is connected to the electromagnetic valve AF4, the bidirectional electromagnetic valve AF5 and the bidirectional electromagnetic valve AF6, and is used for independently vacuumizing each section of the filling pipeline.

[0055] One end of the electromagnetic valve AF7 is connected to the filter connected to the atmosphere, and the other end of the electromagnetic valve AF7 is connected to the electromagnetic valve AF4, the bidirectional electromagnetic valve AF5 and the bidirectional electromagnetic valve AF6, and is used for re-pressurizing each section of the filling pipeline.

[0056] One end of the electromagnetic valve AF9 is connected to a dry high-pressure gas source, and the other end of the electromagnetic valve AF9 is connected to the electromagnetic valve AF4, the bidirectional electromagnetic valve AF5 and the bidirectional electromagnetic valve AF6, and is used for blowing and cleaning each section of the filling pipeline.

[0057] The B system further comprises a 1# liquid storage tank, a 2# liquid storage tank, a 3# liquid storage tank, a pneumatic valve BF1, a pneumatic valve BF2, a pneumatic valve BF3, an electromagnetic valve BF4, a bidirectional electromagnetic valve BF5, a bidirectional electromagnetic valve BF6, an electromagnetic valve BF7, an electromagnetic valve BF8, an electromagnetic valve BF9, a flow control valve, a second heating belt and a vacuum flashboard valve, and constitutes a first set of variable viscosity working medium filling system; and the connection relationship between the B system and the A system is the same.

[0058] Preferably, the phase change working medium filling system lower end filling joint is sealed and connected with the liquid filling pipe of the phase change energy storage device to be filled through a sealing ring, and can adapt to a 3mm or 4mm outer diameter liquid filling pipe.

[0059] Preferably, the flow control valve and each pneumatic valve are compatible with the filling working medium material.

[0060] The heating belt is used for heating the flow control valve.

[0061] The filling system includes four sets of pipelines: a filling pipeline, a vacuumizing pipeline, a high-pressure nitrogen pipeline, and an atmospheric pressure restoring pipeline. The filling pipeline is a working medium flow channel, which is sequentially connected with each liquid tank, pneumatic valve, flow control valve, and filling joint in a vertical direction from top to bottom. The vacuumizing pipeline is mainly used for vacuumizing the filling pipeline of the liquid tank and vacuumizing each stage, and can also realize static vacuum degassing of the working medium. The high-pressure nitrogen pipeline is mainly used for compacting the filled product container, and can also realize pipeline blowing and cleaning. The atmospheric pressure restoring pipeline is realized by directly connecting the atmosphere.

[0062] Among the three liquid tanks, the 1# liquid tank is open and is not vacuumized, and the other liquid tanks are closed, with volumes of 1L, 600mL, and 300mL, respectively. The material is 316L, the liquid tank has a liquid level meter outside, the main material is glass and stainless steel 316L, and is marked with a scale for capacity testing and volume calibration. The reading accuracy of the 3# liquid tank liquid level meter is 1mL.

[0063] As shown in Figure 1 and Figure 2 The above variable viscosity working medium filling device simultaneously fills two independent variable viscosity working medium filling systems to realize parallel filling of two different variable viscosity working media. The two independent variable viscosity working medium filling systems can be placed in a walk-in high temperature oven. The working medium filling system and the oven are both provided with a hub for easy movement.

[0064] The two variable viscosity working medium filling systems share a filter connected to the atmosphere and a vacuum pump set, and can realize vacuumizing the empty load of the variable viscosity working medium filling system to below 1Pa within 10min.

[0065] The vacuum pump set is composed of a double-stage scroll pump, a vacuum gauge, a vacuum meter, and a vacuum flapper valve. The scroll pump is connected with the filling station pipeline system through the vacuum flapper valve. The vacuum meter is installed at the inlet of the filling station vacuumizing pipeline. The vacuum meter is installed on the measurement and control cabinet panel to collect and display the pressure signal of the vacuum gauge.

[0066] The oven provides a high-temperature environment for the filling device, the temperature control range is 15-200 DEG C, the oven temperature uniformity is better than +2 DEG C, the oven heating process is uniform, the temperature rises from room temperature to 160 DEG C, and the temperature rising time is controlled to be less than 1h. The oven provides a standard external interface for standard lead and vacuum pipeline.

[0067] The measurement and control device is integrated in the measurement and control cabinet and is composed of a PLC controller, a touch screen, a sensor, an output driver, a power distribution module and the like. The sensor is mainly responsible for real-time signal acquisition and analysis of environmental parameters and running equipment, and makes a quick response through the PLC controller, sends a control signal to each control device, and the control signal reaches the actuator through the output driver, so that the corresponding device starts to work and achieves the control target.

[0068] The filling method of the variable-viscosity working medium filling device is the same as that of the system B, and the filling method of the variable-viscosity working medium filling device provided by the application comprises the following steps:

[0069] S1, injecting the working medium into the 1# liquid storage tank, and waiting for the filling phase change energy storage device to be installed to the filling joint;

[0070] S2, starting the oven and heating the whole to a set temperature, so that the viscosity of the variable-viscosity working medium is greatly reduced;

[0071] S3, setting the initial state of all pneumatic valves and electromagnetic valves to a closed state;

[0072] S4, opening the vacuum pump, the vacuum baffle valve and the electromagnetic valve AF8;

[0073] S5, opening the electromagnetic valve AF4, and vacuumizing the 2# liquid storage tank and the connecting pipeline;

[0074] S6, closing the electromagnetic valve AF4, opening the pneumatic valve AF1, and filling the working medium into the 2# liquid storage tank until the working medium in the 2# liquid storage tank reaches a first preset capacity, and then closing the pneumatic valve AF1;

[0075] S7, opening the bidirectional electromagnetic valve AF5, and vacuumizing the 3# liquid storage tank and the connecting pipeline;

[0076] S8, closing the bidirectional electromagnetic valve AF5, opening the pneumatic valve AF2, and filling the working medium into the 3# liquid storage tank until the working medium in the 3# liquid storage tank reaches a second preset capacity, and then closing the pneumatic valve AF2;

[0077] S9, opening the pneumatic valve AF3 and the bidirectional electromagnetic valve AF6, and vacuumizing the phase change energy storage device to be filled;

[0078] S10, closing the pneumatic valve AF3 and the bidirectional electromagnetic valve AF6, and opening the flow control valve to fill the working medium into the pipeline in front of the pneumatic valve AF3.

[0079] S11, open the pneumatic valve AF3, fill the working medium into the phase change energy storage device, detect and control the working medium flow by using the flow control valve, until the medium in the phase change energy storage device to be filled meets the preset liquid filling amount requirement;

[0080] S12, close the pneumatic valve AF3, take down the phase change energy storage device to be filled, weigh, compare the weight change before and after weighing, and the filling is completed; the first preset capacity is 1 / 2-2 / 3 of the volume of the 2# liquid storage tank, and the second preset capacity is 1 / 2-2 / 3 of the volume of the 3# liquid storage tank.

[0081] The vacuum degree of the vacuum state is less than 1Pa.

[0082] The filling flow of the variable viscosity working medium is controlled by the pneumatic valve and the flow control valve, the filling rate is adjusted in the range of 10-50mL / min, and the filling deviation of the phase change working medium is not more than 2mL.

[0083] The variable viscosity working medium is a carbon nanometer fluid working medium.

[0084] Figure 4 The variable viscosity working medium filling device is developed according to the flow chart. The variable viscosity working medium filling device comprises the following steps:

[0085] 1, test and analyze the physical property parameters of the carbon nanometer fluid working medium, determine the viscosity, density and thermal expansion characteristics of the working medium at different temperatures, select the filling process control temperature and calculate the filling working medium volume / mass at the corresponding temperature;

[0086] 2, design of vacuum high-temperature filling working principle and control method.

[0087] 3, design of filling system structure layout.

[0088] 4, equipment installation, pipeline assembly, pressure maintaining leak detection, cleaning detection.

[0089] 5, equipment wiring and electrical measurement, system joint test, filling test.

[0090] The present application provides a variable viscosity working medium filling system, device and control method, which is used for the metering filling of carbon nanometer fluid working medium with extremely large viscosity range. The oven is used to heat the filling system and the working medium as a whole to realize the low viscosity flow and flow measurement of high viscosity working medium in high temperature state, the staged gradient vacuumizing and working medium filling are used to realize the static removal of working medium micro-bubbles and the gas space filling of filling container, the liquid level meter measurement, liquid flow controller regulation and weighing are used to realize the accurate process control of filling amount. Compared with the solid cold pressure filling and vacuum melting filling method, the present application realizes the static removal of working medium micro-bubbles, the non-space filling of micro-structure complex cavity and the accurate measurement of filling amount in the filling process of high viscosity carbon nanometer fluid working medium.

[0091] Although the present application has been disclosed with the above preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application by using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical solutions of the present application shall fall within the protection scope of the present application.

Claims

1. A variable viscosity working fluid charging system characterized by The filter, the first liquid storage tank, the second liquid storage tank, the third liquid storage tank, the first pneumatic valve, the second pneumatic valve, the third pneumatic valve, the first electromagnetic valve AF4, the first bidirectional electromagnetic valve AF5, the second bidirectional electromagnetic valve AF6, the second electromagnetic valve AF7, the third electromagnetic valve AF8, the fourth electromagnetic valve AF9, the flow control valve and the vacuum flashboard valve are sequentially connected from top to bottom. The first liquid storage tank, the first pneumatic valve, the second liquid storage tank, the second pneumatic valve, the third liquid storage tank and the flow control valve are sequentially connected from top to bottom, and the third pneumatic valve is connected with the filling joint. The first electromagnetic valve is connected between the first pneumatic valve and the second liquid storage tank, the first bidirectional electromagnetic valve is connected between the second pneumatic valve and the third liquid storage tank, and the second bidirectional electromagnetic valve is connected between the flow control valve and the third pneumatic valve. One end of the third electromagnetic valve is connected with the vacuum flashboard valve connected with the vacuum pump group, and the other end is connected with the first electromagnetic valve, the first bidirectional electromagnetic valve and the second bidirectional electromagnetic valve, so as to independently vacuumize each section of the filling pipeline. One end of the second electromagnetic valve is connected with the filter and connected with the atmosphere, and the other end is connected with the first electromagnetic valve, the first bidirectional electromagnetic valve and the second bidirectional electromagnetic valve, so as to re-pressurize each section of the filling pipeline. One end of the fourth electromagnetic valve is connected with the dry high-pressure gas source, and the other end is connected with the first electromagnetic valve, the first bidirectional electromagnetic valve and the second bidirectional electromagnetic valve, so as to purge and clean the filling pipeline.

2. A variable viscosity working fluid charging device according to claim 1, wherein The filling joint at the lowermost end of the phase-change working medium filling system is sealed and connected with the liquid filling pipe of the phase-change energy storage device to be filled through a sealing ring.

3. A variable viscosity working fluid charging device as set forth in claim 1 wherein, The flow control valve and the pneumatic valves are compatible with the filling working medium.

4. A variable viscosity working fluid charging device as set forth in claim 1 wherein, The liquid level meter is arranged outside the liquid storage tank and is used for capacity measurement and calibration.

5. A variable viscosity working fluid charging device as set forth in claim 1 wherein, The variable-viscosity working medium filling system, the oven, the vacuum pump group, the measurement and control device and the nitrogen source are connected. The variable-viscosity working medium filling system is placed in the oven, the oven provides a temperature control environment for the filling device, the vacuum pump group is used for vacuumizing the second liquid storage tank, the third liquid storage tank and the filling pipeline, the nitrogen source is used for compacting the container in the phase-change energy storage device after filling and purging and cleaning the filling pipeline, and the measurement and control device monitors the oven temperature, the vacuum degree, the capacity in each liquid storage tank and the working medium filling flow, and controls the opening and closing of the pneumatic valves and the electromagnetic valves according to a pre-programmed control time sequence, so that the variable-viscosity working medium is filled by using a hierarchical gradient method after being heated and liquefied.

6. A method of charging a variable viscosity working fluid charging device according to claim 5, characterized in that, The method comprises the following steps: S1, injecting the working medium into the first liquid storage tank, and mounting the phase-change energy storage device to be filled to the filling joint; S2, turning on the oven and heating the whole to a set temperature, so that the viscosity of the variable-viscosity working medium is greatly reduced; S3, setting the initial state of all the pneumatic valves and the electromagnetic valves to a closed state; S4, turning on the vacuum pump, the vacuum flashboard valve and the third electromagnetic valve; S5, turning on the first electromagnetic valve, and vacuumizing the second liquid storage tank and the connecting pipeline; S6, turning off the first electromagnetic valve, turning on the first pneumatic valve, filling the working medium into the second liquid storage tank, and turning off the first pneumatic valve until the working medium in the second liquid storage tank reaches a first preset capacity. S7, open the first two-way electromagnetic valve, and vacuumize the third liquid tank and the connecting pipeline; S8, close the first two-way electromagnetic valve, open the second pneumatic valve, and fill the working medium into the third liquid tank until the working medium in the third liquid tank reaches the second preset volume, and then close the second pneumatic valve; S9, open the third pneumatic valve and the second two-way electromagnetic valve, and vacuumize the phase change energy storage device to be filled; S10, close the third pneumatic valve and the second two-way electromagnetic valve, close the third electromagnetic valve, close the vacuum pump group, open the flow control valve, and fill the working medium into the pipeline in front of the third pneumatic valve; S11, open the third pneumatic valve, fill the working medium into the phase change energy storage device to be filled, and detect and control the working medium flow by using the flow control valve until the medium in the phase change energy storage device to be filled meets the preset liquid filling amount requirement; S12, open the fourth electromagnetic valve, open the dry high-pressure gas source switch, and pressurize the pipeline; S13, open the second two-way electromagnetic valve, and then close the second two-way electromagnetic valve after the high-pressure nitrogen gas compacts the working medium in the filling pipeline and the phase change energy storage device; S14, close the third pneumatic valve, take down the phase change energy storage device to be filled, weigh it, compare the weight change before and after weighing, and complete the filling.

7. A method of charging a variable viscosity working fluid charging device as defined in claim 6, wherein, The first preset volume is 1 / 2-2 / 3 of the volume of the second liquid tank, and the second preset volume is 1 / 2-2 / 3 of the volume of the third liquid tank.

8. The method of charging a variable viscosity working fluid charging device of claim 6, wherein, The vacuum degree of the vacuum state is 1 Pa or less.

9. The method of charging a variable viscosity working fluid charging device of claim 6, wherein, The filling flow of the variable-viscosity working medium is controlled by the pneumatic valve and the flow control valve, the filling rate is adjusted in the range of 10-50 mL / min, and the single filling deviation of the phase change working medium is not more than 2 mL.

10. A variable viscosity working fluid charging device according to any one of claims 6 to 9, wherein The variable-viscosity working medium is a carbon nano fluid working medium.

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