RU2225332C1 - Method of removal of liquid from hydraulic lines of spacecraft systems equipped with hydropneumatic compensators and device for realization of this method - Google Patents

Abstract

FIELD: space engineering; methods of removal of liquid components of working media from hydraulic lines and reservoirs of spacecraft systems. SUBSTANCE: proposed method includes measurement of present volume of liquid and removal of excessive amount by forcing-out the liquid by air pressure in compensator to preliminarily evacuated receiving reservoir connected to system; in the course of forcing-out the liquid, it is absorbed and kept by porous hydrophilic material with open pores; after complete removal of liquid, receiving reservoir is disconnected from system and is brought into communication with outer space; liquid is evaporated by heating to temperature at which pressure of saturated vapor exceeds total hydraulic resistance of route discharging vapor to surrounding medium; this temperature is maintained at constant level till complete removal of liquid. Device proposed for realization of this method includes pneumatic line connecting the gas cavity of compensator with habitable compartment and having absolute pressure measuring instrument, valve distributing equipment and vacuum pipe line fitted with swivel momentless nozzle with two electromagnetic valves and pressure sensor. Device is additionally provided with receiving reservoir and reference receiver; receiving reservoir is connected with hydraulic line of system on one side by means of additional electromagnetic valve and is brought in communication with vacuum pipe line on other side; vacuum pipe line is provided with throttle valve at its outlet; receiving reservoir is filled with hydrophilic porous material with open pores whose total volume is equal to maximum one-time volume of liquid being discharged; device includes heater with temperature sensors; reference receiver is mounted in pneumatic line and is provided with additional pressure sensor. EFFECT: enhanced reliability and safety of spacecraft. 3 cl, 1 dwg

Description

The invention relates to space technology, specifically to methods for removing liquid components of the working fluid from hydraulic lines and capacities of spacecraft systems equipped with a hydropneumatic compensator, and can be used in the manufacture and industrial use of such technology.

The operating experience of domestic orbital stations and modules as part of the Salyut and Mir complexes showed that operations to partially or completely remove an unaccounted amount of liquid components from tanks and hydraulic lines of various kinds of spacecraft systems (for example, temperature control systems, water recovery, life support systems, fuel tanks of propulsion systems, etc.) in the process of their maintenance or any repair work in flight are a fairly common form of practical th crew activities.

Carrying out these works allows you to maintain the operating parameters of the systems at the optimal level, which makes it possible, ultimately, to ensure their normal performance and the established warranty use resource.

Moreover, such work should be completely safe for the crew, not violate the ecology of the environment surrounding the spacecraft and not have a negative impact on the structural elements of the orbital complex.

A known method of draining liquid on a spacecraft according to the author's certificate of the USSR No. 1811132, class. B 64 G 1/50.

The method provides for hydraulic localization of the damaged section of the hydraulic system, evacuation of an autonomous sealed drain tank, the volume of which exceeds the internal volume of the damaged section, to a pressure that ensures complete removal of the drained liquid from the damaged section. After the message of one end of the damaged section of the hydraulic highway with the tank, and the other end with the atmosphere of the habitable compartment, the liquid is drained into the tank due to its displacement by the pressure of the compartment atmosphere.

The method has the following disadvantages:

1) fundamentally cannot provide a specific dosed discharge of liquid, because after one end of the hydraulic line is connected to the tank, and the other to the compartment atmosphere, the current drain is not regulated and is carried out until it is completely displaced into the tank;

2) requires mandatory verification of the tightness of the container after draining the liquid and storing the container in the habitable compartment for a certain time until it is removed from the compartment;

3) the method provides for a one-time use of the tank, therefore, for each subsequent operation of draining the fluid requires a new tank;

4) the method provides for a number of auxiliary technological operations related to the one-time use of drain containers (for example, sealing containers after draining the liquid in them, transferring containers to a temporary storage place, removing containers from the spacecraft in compliance with the necessary safety measures, etc. )

This method is implemented in a device including a pneumatic line connecting the drain tank with the damaged section of the hydraulic line, and a vacuum pipe communicating the tank with an outboard vacuum or an onboard compressor for evacuating it.

The disadvantages of the device:

1) the device lacks controls for draining and the volume of the liquid being drained;

2) the device involves the installation of a new tank for each fluid drain operation;

3) the disposability of the use of the container necessitates the delivery and storage of spare tanks on board the spacecraft;

4) containers with fused components of the working fluid are stored for a certain time in the inhabited compartments of the spacecraft, which reduces the safety of the crew.

Also known are “A method for draining components from hydraulic lines of auxiliary systems of spacecraft equipped with a hydropneumatic compensator and a device for its implementation”, protected by the patent of the Russian Federation No. 2067954, adopted by the author as prototypes.

In this method, based on the communication of the hydraulic circuit of the system with vacuum and the displacement of the component by air pressure in the hydropneumatic compensator of the system, before the communication of the hydraulic circuit with vacuum, the current volume of the gas cavity of the compensator is measured and the initial pressure equal to the atmospheric pressure of the inhabited compartments is set in it, and then, when communicating hydraulic lines with the vacuum surrounding the spacecraft, control the change in air pressure in the gas cavity of the compensator and when the pressure reaches values determined from the ratio given in the claims, stop draining the component.

In the known device for implementing the method of draining components from the hydraulic lines of auxiliary systems of spacecraft equipped with a hydropneumatic compensator containing a pneumatic line connecting the gas cavity of the compensator with the atmosphere of the inhabited compartment, and a pipeline for draining the component from the hydraulic line of the system into a vacuum, two electromagnetic coaxially installed in the mentioned pipeline are used valves, between which a pressure sensor is installed, and the pneumatic line additionally contains um absolute pressure measuring device, the shut-off valve and the end fitting for connecting an external pressure source.

The experience of the repeated use of this technology on the Mir orbital complex showed that, along with the known advantages, the method and device for its implementation are not without a number of disadvantages that significantly limit the possibility of their use in unchanged form on spacecraft with a developed external design architecture like the International Space Station.

The disadvantages of the method include:

1) the negative (destructive) effect of the component being drained on the structural elements of the outer architecture of the spacecraft, since the liquid stream at the outlet of the expansion nozzle of the vacuum pipeline under real conditions of the space environment turns into a torch consisting of droplets of various sizes and having a solid opening angle of ~ 180 ° .

Thus, under the influence of this torch, all the structural elements of the spacecraft located in the hemisphere of liquid discharge are found.

Small droplets of liquid due to intense evaporation in a vacuum almost immediately freeze and turn into ice particles, which upon impact with some structural elements (solar cells, sensitive infrared sensors, temperature-controlled coatings, etc.) have a gradual destructive effect on them.

Large drops of liquid, falling on the surface of solar panels, windows, optical sensors and freezing there, during their further sublimation leave behind a film that degrades the optical characteristics of these elements.

When the components of rocket fuel are discharged, small particles of ice are formed with brisant properties (they explode upon collision with structural elements). Such particles severely damage the surface of these elements, causing deep erosion of the material;

2) since the discharge of the liquid component is carried out directly from the system and is controlled only by the astronaut, as a result of an error made by him (something distracted, the drain was not stopped on time, etc.), a complete emptying of the liquid cavity of the compensator is possible, which will lead to exit systems out of order.

The disadvantages of the device include:

1) the fundamental impossibility of obtaining a narrowly directed jet of the component being drained, due to the real physical laws of fluid flow under vacuum and zero gravity, which excludes guaranteed protection of structural elements in almost the entire hemisphere of the drain;

2) the lack of circuit protection against errors of the astronaut or one failure in the device, leading to the failure of the system;

3) the absence in the composition of the device of means to determine excess excess fluid in the compensator system.

The objective of the present invention is to increase the safety and reliability of the method and device for its implementation.

The technical result from the use of the invention is that the proposed method and device allow:

- to ensure safe removal of fluid from the hydraulic lines of the systems without exerting a negative (destructive) effect on the external structural elements of the spacecraft;

- to improve the reliability of the method by introducing operational control of the process of liquid removal;

- provide direct measurement of the volume of the gas cavity of the compensator system in order to determine the excess amount of fluid in the system;

- eliminate the possibility of a system failure when removing fluid due to crew errors or the failure of one element in the device.

The problem is solved in that in the method of removing liquid from the hydraulic lines of spacecraft systems equipped with a hydropneumatic compensator, including measuring the current volume of liquid in the system and removing its excess amount by displacing the liquid with air pressure in the compensator into a receiving tank previously evacuated and hermetically connected to the system, in the process of displacing a liquid into a container, it is absorbed and held in it by a porous hydrophilic material with open pores, and then, after the complete removal of the removed liquid, the receiving tank is disconnected from the system, the external environment is communicated with the spacecraft, and the liquid is evaporated by heating the contents of the container to a temperature at which the pressure of saturated vapor of the liquid exceeds the total hydraulic resistance of the vapor transport path to the external environment and keep this temperature constant until the liquid is completely removed.

In a device for removing liquid from the hydraulic lines of spacecraft systems equipped with a hydropneumatic compensator, including a pneumatic line connecting the gas cavity of the compensator to the inhabited compartment and containing an absolute pressure measuring device, valve-distribution valves, and also a vacuum pipe with a rotary momentless nozzle equipped with two series-mounted solenoid valves and a pressure sensor; additionally, a receiving tank and a reference Iver, moreover, the receiving tank, on the one hand, is connected through an additional electromagnetic valve to the system’s hydraulic line, and, on the other hand, is connected to a vacuum pipe at the outlet of which a choke is installed into the environment, while the receiving tank is filled with open-pore hydrophilic porous material, the total volume of which equal to the maximum one-time volume of liquid to be removed, and contains a heater with temperature sensors, and the reference receiver is installed in the pneumatic line and is equipped with an additional pressure sensor.

The invention is illustrated by the drawing, where on the example of a device for removing the coolant from the hydraulic line of the spacecraft thermal control system equipped with a hydropneumatic compensator, its basic pneumohydraulic diagram is shown.

The diagram indicates:

1 - pneumatic line;

2 - inhabited airtight compartment;

3 - manual shut-off valve;

4 - pressure seal;

5 - throttle;

6 - hydropneumatic compensator;

7 - leaking aggregate compartment;

8 - thermal line of the temperature control system;

9 - pipeline;

10 - pressure seal;

11 - pressure seal;

12 - reference receiver;

13 - telemetric pressure sensor;

14 - measuring device of absolute pressure;

15 - fitting;

16 - fitting;

17 - a throttle;

18 - a throttle;

19 - throttle;

20 - manual shutoff valve;

21 - manual shutoff valve;

22 - manual shutoff valve;

23 - manual shutoff valve;

24 - receiving capacity;

25 - hydrophilic porous material;

26 - heater;

27 - heater;

28 - temperature sensor;

29 - temperature sensor;

30 - screen-vacuum thermal insulation;

31 - vacuum pipeline;

32 - the electromagnetic valve;

33 - the electromagnetic valve;

34 - telemetric pressure sensor;

35 - throttle;

36 - rotary momentless nozzles;

37 - trunk solenoid valve;

38 - pipeline.

The proposed device consists of three main functional parts: pneumatic line 1, the receiving tank 24 and the vacuum pipe 31.

The pneumatic line 1 is located in a sealed hermetic compartment 2 of the spacecraft and, through a manual shut-off valve 3, a pressure seal 4 and a throttle 5, is connected to the gas cavity of the hydropneumatic compensator 6 of the temperature control system located in an unpressurized aggregate compartment 7.

The hydro-pneumatic compensator 6 is in communication with the hydraulic line of the temperature control system 8 using the pipeline 9.

The hydraulic line of the temperature control system 8, which includes all the other necessary units (hydraulic pumps, heat exchangers of all types, valves, etc.), ensuring its normal functioning and regulation of the thermal regime of the spacecraft elements, passes through the entire product and is connected, including number, and with the inhabited airtight compartment 2 through the pressure glands 10, 11.

The receiving tank 24 and the vacuum pipe 31 are also placed in the leaky aggregate compartment 7.

The pneumatic line 1 combines a reference receiver 12, equipped with, for example, a telemetric pressure sensor 13, an absolute pressure measuring device 14 and two fittings 15 and 16, each of which is equipped with a sealing plug. The fitting 15 is designed to communicate the pneumatic line 1 with the atmosphere of the inhabited airtight compartment 2, and the fitting 16 is used to connect on-board sources of high or low pressure.

The reference receiver 12, the absolute pressure measuring device 14 and the fitting 15 are connected to the pneumatic line 1, respectively, through the throttles 17, 18, 19 and manual shut-off valves 20, 21, 22; the fitting 16 is connected to the pneumatic line 1 through a manual shut-off valve 23.

As a measuring instrument of absolute pressure 14, the device uses the well-proven VK-316M manovacuum meter, which has proven itself at the Mir orbital station, which does not have an electrical transducer of measured value, but has a high accuracy of measurement (± 0.5 mm Hg) of absolute pressure Wednesday. The use of such an accurate device follows from the method for determining the current volume of the gas cavity of the system compensator, where the high accuracy of the volume measurement is determined by the high accuracy of the pressure measurement. Other means of measuring pressure (for example, telemetric sensors such as MDDAS 100-2300 or DAP 1-4000) do not have such accuracy.

The receiving tank 24 is a low-pressure spherical balloon, the inner cavity of which is filled with cubes of hydrophilic porous material 25. As a material in the device under consideration, Akvipor TU-6-05-221-833-87 polyvinyl formal foam can be used (for other systems using aggressive liquids, for example, propellant components of propulsion systems, use porous materials based on metals - foamed nickel, etc.).

On the outer surface of the receiving tank 24, heaters 26 and 27 are installed, made, for example, in the form of two sections of electric heating and temperature sensors 28 and 29. Power is supplied to the heaters 26 and 27 from the on-board power supply system in accordance with the algorithms of the on-board computer using electrical signals from temperature sensors 28 and 29. Outside, the receiving tank 24 is insulated by a screen-vacuum thermal insulation 30.

The internal volume of the receiving tank 24 is in communication with the vacuum pipe 31 through two sequentially installed solenoid valves 32 and 33, between which a telemetric pressure sensor 34 is installed. At the end of the vacuum pipe 31, a choke 36, which is factory-set, is installed at the factory and limits the flow rate of the coolant vapor, as well as located outside the leaky aggregate compartment 7 rotary momentless nozzles 35, designed to discharge the vapors of the removed coolant into outer space without perturbing effects on the orientation system of the spacecraft. In addition, the internal volume of the receiving tank 24 through the main electromagnetic valve 37 is connected by a pipe 38 to the hydraulic circuit of the temperature control system 8.

Both telemetric pressure sensors (13 and 34) have two electrical outputs, one of which is electrically connected to the on-board measurement system, and the other to the on-board computer.

Absolute pressure measuring device 14, manual shut-off valves 3, 20, 21, 22, 23, fittings 15, 16 are placed on one structural panel.

The device operates as follows.

During the annual routine maintenance on board the spacecraft, one of the operations is to determine the excess standard amount of coolant in the thermal control system and remove this coolant from the system.

To perform this operation, the crew carries out the following operations:

1) connects the system Lap-top to the central on-board computer, initiates a device mnemonic on its display and monitors its initial state according to the readings of telemetric pressure sensors 13, 34;

2) measures the current volume of the gas cavity of the hydropneumatic compensator 6. The measurement is carried out using the “reference capacity” method, as set forth, for example, in the industry standard “Thermal control systems. The technique of refueling with coolants ”OST 92-9470-81.

Using this method, using an absolute pressure measuring device 14, the crew sequentially accurately measures the air pressure in the gas cavity of the hydropneumatic compensator 6 and the air pressure in the reference receiver 12.

To measure the air pressure in the gas cavity of the hydropneumatic compensator 6, the crew sequentially opens the manual shut-off valves 3 and 21, fixes the pressure on the scale of the absolute pressure measuring device 14 and enters the obtained value into the corresponding program of the on-board computer. After completing this operation, the crew closes the manual shutoff valve 3.

To accurately measure the air pressure in the reference receiver 12, the crew opens the manual shut-off valve 20, fixes the pressure on the scale of the absolute pressure measuring device 14 and enters the obtained value into the on-board computer program. The volume of the reference receiver, measured at the factory with high accuracy, is preliminarily taken into account in the program;

3) opens the manual shut-off valve 3, fixes the steady-state air pressure in the system “hydropneumatic compensator 6 - reference receiver 12” and enters the obtained value into the on-board computer. Since the dependence of the current volume of the gas cavity of the hydropneumatic compensator 6 on the measured pressures and the volume of the reference receiver 12 is implemented in a computer program, on the Lap-top display the crew immediately receives the values of the current volume of the gas cavity, the volume of the fluid dose to be drained (the volume of the dose to be drained is equal to the difference between the value of the nominal (normative) volume of the gas cavity and the measured value of the current volume of the gas cavity) and the pressure in the gas cavity of the compensator, at which it is necessary to stop the removal of coolant from the system. In this case, as the initial pressure in the gas cavity of the compensator, at which the displacement of the coolant from the system begins, the computer selects the steady-state pressure in the system “hydropneumatic compensator 6 - reference receiver 12”. Then the crew closes the manual shut-off valve 20;

4) evacuate the receiving tank 24. For this, by command with the Lap-top, it opens the solenoid valves 32, 33. The evacuation process is controlled at the Lap-top according to the readings of the telemetric pressure sensor 34.

When a certain pressure is reached in the receiving tank 24 (less than 2-3 mm Hg), the computer closes the solenoid valves 32, 33 and gives a message on the Lap-top display about the readiness of the device for the operation to remove the coolant;

5) opens the main solenoid valve 37 with the Lap-top and controls the change in air pressure in the gas cavity of the hydropneumatic compensator 6 using an absolute pressure measuring instrument 14. The air pressure in the gas cavity of the hydropneumatic compensator 6 drains the coolant dose into the receiving tank 24, where it is absorbed by the hydrophilic porous 25. When the controlled pressure reaches the value calculated by the computer, the crew stops draining the coolant, closing the main line with the Lap-top solenoid valve 37.

In the process of draining the dose to the receiving tank 24, it sets the pressure of saturated vapor of the coolant, corresponding to its current temperature. This pressure is taken into account in the computer program when determining the final pressure in the gas cavity of the hydropneumatic compensator 6, at which it is necessary to stop draining;

6) starts with Lap-top the algorithm for evaporating the coolant. According to this algorithm, the electromagnetic valves 32, 33 are opened, the heaters 26, 27 are supplied and the coolant in the receiving tank 24 is heated to a predetermined temperature (depending on the type of coolant and the hydraulic resistance of the vapor recovery path), which is maintained constant until the completion of the evaporation of the coolant from receiving capacity 24. The operation of the heaters 26, 27 is controlled by the on-board computer based on signals from temperature sensors 28, 29.

From the moment of opening of the electromagnetic valves 32, 33, evaporation of the heat carrier from the receiving tank 24 and removal of vapors through the vacuum pipe 31 and rotary torqueless nozzles 36 begins. During heating of the heat carrier the pressure of its saturated vapors rises and the evaporation process reaches the calculated mode.

The steam flow through the vacuum pipe 31 is limited by the throttle 35, the hydraulic resistance of which is selected based on the physical characteristics of a particular type of liquid to be removed, in particular, the vaporization coefficient, during ground testing of the device design.

This allows you to reduce the steam emission per unit time to an acceptable safe value for environmental reasons, taking into account the movement of the spacecraft in orbit.

At the exit from the rotary momentless nozzle 36, coolant vapors are released into open space in the form of rarefied hemispherical flares, without damaging the structural elements of the spacecraft due to their low density and high sparseness. Subsequently, under the action of the ultraviolet component of solar radiation, vapors decompose into individual molecules and do not adversely affect the ecology of the environment.

The process of evaporation of the coolant occurs without the participation of the crew and is completely controlled by the on-board computer using a telemetric pressure sensor 34. After the completion of the evaporation operation (almost complete removal of the coolant from the receiving tank 24), the pressure of the medium in the receiving tank 24 drops sharply to a level of 30-40 mm RT. Art. lower pressure of saturated vapor of the coolant at a controlled temperature, and the computer issues commands to turn off the heaters 26, 27 and close the solenoid valves 32, 33, and then generates a message on Lap-top about the completion of the operation to remove the coolant from the system;

7) controls the parameters of the device on the Lap-top, sets the nominal working pressure in the gas cavity of the hydropneumatic compensator and brings the device to its original state.

In the process of setting the nominal working pressure in the gas cavity of the hydropneumatic compensator 6 and bringing the device to its initial state, the crew can connect on-board sources 16 high (pressure higher than the pressure in the inhabited pressurized compartment 2) and low (pressure lower than the pressure in the inhabited pressurized compartment 2) pressure or to discharge excess air from the device into the atmosphere inhabited airtight compartment through the fitting 15.

Thus, the totality of new features that are absent in the known technical solutions, makes it possible to create a method and device that allows:

- to provide a safe, not having a negative destructive effect on the elements of the outer structure of the spacecraft, the removal of liquid from the hydraulic lines of various systems by evaporating it on board and the release of rarefied vapors into the surrounding space;

- reduce the time of routine maintenance by eliminating auxiliary technological operations (assembling a pneumatic circuit to determine the volume of the gas cavity of the compensator, checking its tightness, etc.);

provide direct measurement of the volume of the gas cavity of the compensator system by means of the device itself;

to exclude the possibility of a system failure when liquid is removed due to crew errors or the failure of any one element in the device, because the volume of liquid to be removed is limited by the design of the receiving tank and does not exceed the maximum one-time volume of the removed excess excess liquid.

All this, in general, allows to ensure the reliability and safety of the spacecraft, save the crew’s work time, and save the structural resource of the material part.

The proposed method and device were developed in order to fulfill the production task for the temperature control system of the Zvezda service module of the Russian segment of the International Space Station. Taking into account the real terms of scheduled repair and maintenance work with the system, the main part of the device’s design will be delivered to the station by one of the Progress cargo ships and mounted by the crew. The rest of the device, located in hard-to-reach places, is mounted at the factory of the service module.

Claims (2)

1. A method of removing liquid from the hydraulic lines of spacecraft systems equipped with a hydropneumatic compensator, including measuring the current volume of liquid in the system and removing its excess amount by displacing the liquid with air pressure in the compensator into a receiving tank previously evacuated and hermetically connected to the system, characterized in that the process of displacing a liquid into a container, it is absorbed and held in it by a porous hydrophilic material with open pores, and then, after In order to oust the removed liquid, the receiving tank is disconnected from the system, communicates with the external environment of the spacecraft and the liquid is evaporated, heating the contents of the container to a temperature at which the pressure of saturated vapor of the liquid exceeds the total hydraulic resistance of the vapor transfer path to the surrounding environment and maintain this temperature constant until complete removal of fluid. 2. A device for removing liquid from the hydraulic lines of spacecraft systems equipped with a hydropneumatic compensator, including a pneumatic line connecting the compensator cavity to the inhabited compartment and containing an absolute pressure measuring device, valve-distributing valves, and also a vacuum pipe with a rotary momentless nozzle equipped with two sequentially installed electromagnetic valves and a pressure sensor, characterized in that in its composition additionally introduced reception a capacitance and a reference receiver, the receiving capacitance on the one hand through an additional solenoid valve connected to the hydraulic system, and on the other hand connected to a vacuum pipe at the outlet of which an inductor is installed in the environment, while the receiving capacitance is filled with hydrophilic porous material with open pores , the total volume of which is equal to the maximum single volume of the removed liquid, and contains a heater with temperature sensors, and the reference receiver is installed in the pneumatic line and is equipped with an additional pressure sensor.

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