A temperature and pressure regulating system for automatic air pressure calibration equipment

Abstract

The present invention discloses a temperature and pressure regulating system of an automatic air pressure calibration device, the temperature and pressure regulating system comprising a sealed cavity, a temperature regulating system, a pressure regulating system, and a heat dissipation system controller, the cavity being surrounded by at least four side walls, the temperature regulating system comprising a semiconductor refrigeration unit arranged on the outer wall of the side wall, the semiconductor refrigeration unit cooling or heating according to the direction of the current passing through it, the pressure regulating system comprising a pressure compensation device and a vacuum pump connected to the cavity, the heat dissipation system being in contact with the side wall, and the controller being connected to the temperature regulating system, the pressure regulating system, and the heat dissipation system. The temperature and pressure regulating system of the automatic air pressure calibration device provided by the present invention utilizes PLC programmable control technology, TEC temperature control technology, and capacitance differential pressure instrument pressure module technology to realize a temperature and pressure automatic calibration system of a sky probe.

Description

Technical Field

[0001] The invention relates to a sky detector component calibration system, and in particular to a temperature and pressure regulating system of an automatic air pressure calibration device. Background Art

[0002] Low Earth orbit spacecraft will be affected by the orbital atmospheric environment composed of neutral gases (molecules and atoms) and charged particles. Although the atmospheric density is very low within the range of 300 to 600 kilometers, it will produce a sufficiently large relative flux density at the speed of the spacecraft, and the drag effect it forms on the spacecraft will directly affect the spacecraft's orbit, attitude and life; and the upper atmosphere in the low Earth orbit altitude range is composed of atomic oxygen, and its interaction with the surface of the spacecraft will cause erosion, aging, wear and contamination of the spacecraft surface materials. Therefore, it is necessary to use detectors for direct on-orbit monitoring.

[0003] The atmospheric density is usually obtained by directly measuring pressure and temperature, while the atmospheric composition is essentially obtained by using a detector with a quadrupole mass filter as the core. These detectors need to be calibrated on the ground to obtain the calibration characteristics that must be established for the detectors. Therefore, an ultra-high vacuum active gas calibration system was established for the calibration of O2, N2 and He sensitivity (total pressure and partial pressure), calibration of pattern coefficients, and stability research of detectors. Traditional temperature and pressure calibration systems usually use dry ice cooling and resistance heating for temperature regulation, and pumping and pressure reduction and pressure pumping for pressure regulation. This system has a long relaxation time for the temperature and pressure to reach the set values ​​during testing, and has low work efficiency. In addition, the working environment is full of gasified carbon dioxide and high-decibel noise, which causes great physical harm to the staff. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a temperature and pressure regulating system for an automatic air pressure calibration device, which is highly efficient, can be automatically calibrated, and does not require workers to endure a harsh working environment. The specific scheme is as follows:

[0005] The present invention provides a temperature and pressure regulating system for an automatic air pressure calibration device, the temperature and pressure regulating system comprising

[0006] A cavity, the cavity being surrounded by at least four side walls;

[0007] A temperature regulation system, the temperature regulation system comprising a semiconductor refrigeration unit disposed on the outer wall of the side wall, the semiconductor refrigeration unit cooling or heating according to the direction of the current passing through the semiconductor refrigeration unit;

[0008] a pressure regulating system, the pressure regulating system comprising a pressure compensating device and a vacuum pump connected to the cavity;

[0009] a heat dissipation system, the heat dissipation system being in contact with the side wall;

[0010] A controller is connected to the temperature regulating system, the pressure regulating system and the heat dissipation system.

[0011] Furthermore, the heat dissipation system includes a water-cooled copper pipe connected to a water chiller, and the water-cooled copper pipe is partially in contact with the outer wall of the side wall.

[0012] Furthermore, the semiconductor refrigeration unit is arranged between the water-cooled copper tube and the side wall, there are multiple semiconductor refrigeration units, and interval areas are provided between adjacent semiconductor refrigeration units.

[0013] Furthermore, the semiconductor refrigeration unit is configured as a two-stage refrigeration unit.

[0014] Furthermore, one or more temperature sensors are arranged in the cavity, and the temperature sensors are connected to the controller. The controller adjusts the magnitude and direction of the current passing through the semiconductor refrigeration unit according to the detection results of the temperature sensors.

[0015] Furthermore, the pressure regulation system includes a capacitive pressure differential meter connected to the controller, the capacitive pressure differential meter is used to detect the air pressure in the cavity, and the controller controls the vacuum pump and the pressure compensation device according to the detection result of the capacitive pressure differential meter.

[0016] Furthermore, the temperature and pressure regulation system includes at least the following five stable temperature calibration points: 40℃±0.2℃, 20℃±0.2℃, 0℃±0.2℃, -20℃±0.2℃, -35℃±0.2℃, and five stable air pressure calibration points corresponding to the five temperature calibration points: 950hPa±0.03hPa, 700hPa±0.03hPa, 500hPa±0.03hPa, 200hPa±0.03hPa, 5hPa±0.03hPa.

[0017] Furthermore, the temperature and pressure regulation system includes a first regulation mode, and the first regulation mode is: when the controller controls the temperature regulation system so that the temperature in the cavity changes from a first temperature calibration point to a second temperature calibration point, if the first temperature calibration point is higher than the second temperature calibration point, the change takes 8 to 12 minutes; if the first temperature calibration point is lower than the second temperature calibration point, the change takes 4 to 6 minutes.

[0018] Furthermore, the temperature and pressure regulation system includes a second regulation mode, which is: when the controller controls the temperature regulation system so that the temperature in the cavity changes toward a third temperature calibration point, if the temperature difference between the temperature in the cavity and the third temperature calibration point reaches a first threshold, the change takes 1 to 4 minutes.

[0019] Furthermore, the first threshold is 1°C to 3°C.

[0020] The beneficial effects brought by the technical solution provided by the present invention are as follows:

[0021] A. The temperature and pressure automatic calibration system of the sky probe is realized by using PLC programmable control technology, TEC temperature control technology and capacitance differential pressure meter pressure module technology.

[0022] B. There are multiple adjustment modes to choose from when adjusting the temperature, so that the temperature and air pressure are distributed as evenly as possible when adjusting the temperature and pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 is a partial schematic diagram of a temperature and pressure regulating system provided by an embodiment of the present invention;

[0025] Figure 2 It is a partial top view of the temperature and pressure regulation system provided by an embodiment of the present invention.

[0026] Among them, the reference numerals are: 1-pressure sensor, 2-temperature sensor, 3-water-cooled copper tube, 4-semiconductor refrigeration unit, 5-exhaust hole, 6-cavity. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 creative work should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, device, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0029] In one embodiment of the present invention, Figure 1 , Figure 2 As shown, a temperature and pressure regulating system for an automatic air pressure calibration device is provided, the temperature and pressure regulating system comprising

[0030] The cavity 6 is surrounded by at least four side walls. Figure 1 and attached Figure 2 In the embodiment, the cavity 6 is a rectangular space surrounded by a lower wall and four side walls; in some other embodiments, the cavity 6 may also be in other shapes.

[0031] A temperature regulation system, the temperature regulation system includes a semiconductor refrigeration unit 4 arranged on the outer wall of the side wall, the semiconductor refrigeration unit 4 cools or heats according to the direction of the current passing through it, and the semiconductor refrigeration unit 4 is in a two-stage refrigeration setting, that is, the semiconductor refrigeration unit is composed of an outer refrigeration plate and an inner refrigeration plate superimposed on each other, the inner refrigeration plate is in contact with the outer wall of the side wall, and the heat pumping capacity of the outer refrigeration plate is higher than the heat pumping capacity of the inner refrigeration plate; the cold surface of the outer refrigeration plate is in contact with the hot surface of the inner refrigeration plate, or the hot surface of the outer refrigeration plate is in contact with the cold surface of the inner refrigeration plate, that is, the outer refrigeration plate can transfer the temperature of the inner refrigeration plate, thereby participating in regulating the temperature of the inner refrigeration plate; the controller adjusts the working voltage of the outer refrigeration plate according to the working voltage of the inner refrigeration plate, and the ratio between the two is consistent with the preset proportionality coefficient. The shapes of the two semiconductor refrigeration plates are preferably the same so that they fit perfectly;

[0032] A pressure regulating system, the pressure regulating system comprising a pressure compensating device and a vacuum pump connected to the cavity 6 through the exhaust hole 5, the vacuum pump is used to extract gas from the cavity 6 to reduce the pressure, and the pressure compensating device is used to pass nitrogen into the cavity 6 to increase the pressure in the cavity 6;

[0033] a heat dissipation system, the heat dissipation system being in contact with the side wall;

[0034] A controller is connected to the temperature regulating system, the pressure regulating system and the heat dissipation system.

[0035] In one embodiment of the present invention, the heat dissipation system includes a water-cooled copper tube 3 connected to a water chiller, and the water-cooled copper tube 3 is partially in contact with the outer wall of the side wall; water-cooled copper tubes 3 are provided on the four side walls, and cold water passes through the water-cooled copper tubes 3 under the action of the water chiller, so that the cavity is cooled, and the water chiller is connected to and controlled by the controller.

[0036] In one embodiment of the present invention, the semiconductor refrigeration unit 4 is disposed between the water-cooled copper tube 3 and the side wall, the number of the semiconductor refrigeration units 4 is multiple, and a spacing area is provided between adjacent semiconductor refrigeration units 4; Figure 1 , Figure 2 As shown, the semiconductor refrigeration unit 4 is rectangular, preferably square, the surface where the water-cooled copper tube 3 fits the side wall is rectangular, and the width of the rectangle is such that the water-cooled copper tube 3 just covers the semiconductor refrigeration unit 4, so that the semiconductor refrigeration unit 4 is cooled; as mentioned above, the semiconductor refrigeration unit 4 is a two-stage refrigeration setting, which is equivalent to the outer cooling plate transferring the heat of the inner cooling plate to the water-cooled copper tube, so it is necessary for the water-cooled copper tube 3 to fit and cover the semiconductor refrigeration unit 4, so that the cooling is reliable and efficient. The interval area set between adjacent semiconductor refrigeration units is filled with insulation material to prevent multiple semiconductor refrigeration units 4 from affecting each other.

[0037] In order to make the temperature distribution in the cavity as uniform as possible, semiconductor refrigeration units are correspondingly arranged on the four side walls.

[0038] In one embodiment of the present invention, one or more temperature sensors 2 are arranged in the cavity 6, and the temperature sensors 2 are connected to the controller. The controller adjusts the size and direction of the circuit passing through the semiconductor refrigeration unit according to the detection result of the temperature sensor 2, so that the semiconductor refrigeration unit cools or heats, thereby regulating the temperature in the cavity. The temperature sensors 2 in the cavity should also be arranged as symmetrically and evenly as possible to measure the temperature more accurately.

[0039] In one embodiment of the present invention, the pressure regulation system includes one or more pressure sensors 1 connected to the controller. Preferably, the pressure sensor 1 is a capacitive differential pressure meter, which is used to detect the air pressure in the cavity. The controller controls the vacuum pump and the pressure compensation device according to the detection result of the capacitive differential pressure meter.

[0040] In one embodiment of the present invention, the temperature and pressure regulation system includes at least the following five stable temperature calibration points: 40℃±0.2℃, 20℃±0.2℃, 0℃±0.2℃, -20℃±0.2℃, -35℃±0.2℃, and five stable air pressure calibration points corresponding to the five temperature calibration points: 950hPa±0.03hPa, 700hPa±0.03hPa, 500hPa±0.03hPa, 200hPa±0.03hPa, 5hPa±0.03hPa.

[0041] In one embodiment of the present invention, the temperature and pressure regulation system includes a first regulation mode, and the first regulation mode is: when the controller controls the temperature regulation system so that the temperature in the cavity changes from the first temperature calibration point to the second temperature calibration point, if the first temperature calibration point is higher than the second temperature calibration point, the change takes 8 to 12 minutes; if the first temperature calibration point is lower than the second temperature calibration point, the change takes 4 to 6 minutes. The first regulation mode can also be called a fast mode, the purpose of which is to quickly make the temperature in the cavity reach the target temperature. However, rapid changes in temperature and pressure will cause uneven distribution of temperature and pressure, so an embodiment of the present invention also includes a slow mode, that is, the second regulation mode mentioned below.

[0042] In one embodiment of the present invention, the temperature and pressure regulating system includes a second regulating mode, i.e., a slow mode, wherein the second regulating mode is: when the controller controls the temperature regulating system to make the temperature in the cavity change toward the third temperature calibration point, if the temperature difference between the temperature in the cavity and the third temperature calibration point reaches the first threshold, the change takes 1 to 4 minutes. That is, when the actual temperature approaches the target temperature, the cooling or heating power is reduced so that the actual temperature slowly approaches the target temperature, thereby avoiding the situation where the actual temperature exceeds the target temperature during high-power cooling or heating, and the actual temperature oscillates back and forth in order to obtain the target temperature.

[0043] The fast mode is combined with the slow mode. When the actual temperature is significantly different from the target temperature, high-power heating or cooling is used. When the difference is smaller, low-power heating or cooling is used. This can not only reach the target temperature as quickly as possible, but also provide sufficient relaxation time to avoid the temperature oscillating back and forth near the target temperature. This solution is more energy-saving and safe, and can also make the temperature and pressure distribution in the cavity more uniform.

[0044] In one embodiment of the present invention, the first threshold is a value between 1° C. and 3° C., and any value within this range can be selected to meet different needs.

[0045] In one embodiment of the present invention, the entire system structure consists of an open inner cavity and an outer cavity, wherein the inner cavity includes the cavity and side walls surrounding the cavity. The inner cavity is placed in the outer cavity, and the system sealing is achieved by the outer cavity.

[0046] In one embodiment of the present invention, an adjustable temperature and pressure system for automatic air pressure calibration equipment is provided, comprising the following steps: heating and cooling the vacuum chamber of the calibration system respectively by changing the polarity of the input voltage of a semiconductor refrigeration chip (TEC), the refrigeration chip is arranged in two stages, temperature sampling and control are performed by a platinum resistance temperature sensor 2 and a Mitsubishi temperature module, a micro dry pump and cylinder nitrogen are used to respectively perform pressure reduction, pressurization and set pressure control through an electric butterfly valve and a capacitive pressure differential meter, the hot side of the TEC is cooled by pumping cold water from the cold end outlet water of the circulating water of the chiller, and all control processes are completed by a PLC control module.

[0047] Four groups of two-stage TEC modules are respectively installed on the four outer walls of the inner cavity. The four groups of TEC modules are independently powered. The outer sides of the four groups of TEC modules are close to the water-cooled rectangular copper tube, and the copper tube is filled with circulating cooling water pumped by a chiller.

[0048] Temperature measurement and control are completed using the following strategy. The specific method is: a Pt temperature sensor 2 is installed at a distance of 3cm-8cm from the center of the four inner walls of the inner cavity for temperature measurement. The output end of the Pt temperature sensor is connected to the signal input end of the Mitsubishi temperature control module. The output signal of the Mitsubishi temperature control module is used to control the working voltage of four groups of TEC modules close to the outside of the inner cavity. The working voltage of the four groups of outer TEC modules is adaptively modulated with the working voltage of the inner TEC module using the voltage proportional module through the ratio coefficient obtained by optimizing the working parameters.

[0049] The pressure increase is achieved by nitrogen in a cylinder controlled by an electric butterfly valve, and the pressure reduction is achieved by dry pumping controlled by an electric butterfly valve. The set pressure is sampled and controlled by a capacitance differential pressure meter.

[0050] The system can obtain at least 40℃±0.2℃, 20℃±0.2℃, 0℃±0.2℃, -20℃±0.2℃, and -35℃±0.2℃ controllable stable temperature calibration points. At each temperature calibration point, it can obtain 950hPa±0.03hPa, 700hPa±0.03hPa, 500hPa±0.03hPa, 200hPa±0.03hPa, and 5hPa±0.03hPa stable air pressure calibration points.

[0051] The temperature change rate during the temperature rise and fall process of each temperature calibration point is divided into two modes: fast and slow: fast refers to the transition time from one temperature calibration point to another, about 5 minutes for temperature rise and about 10 minutes for temperature fall; slow refers to the transition time from 1℃ to 3℃ to the temperature calibration point before reaching a temperature calibration point. The set values ​​of the calibrated temperature points and pressure points are adjustable, and the change rate of adjacent temperature sections is adjustable.

[0052] In one embodiment of the present invention, an adjustable temperature and pressure system of an automatic air pressure calibration device is provided, the system includes semiconductor heating, cooling system, heat pool (water chiller), vacuum and pressure generation and control system (pump, differential pressure meter, pressure compensation device), PLC control system, etc. The specific components are Hi-Tec semiconductor chip, heat transfer system, heat pool, thermal insulation component, dry pump, capacitance differential pressure meter, nitrogen pressure compensation system, PLC temperature and pressure control system, and high-precision DC power supply. The system can obtain an environmental system in which pressure and temperature can be adjusted continuously or in stages. The controllable stable temperature calibration points are: 40℃±0.2℃, 20℃±0.2℃, 0℃±0.2℃, -20℃±0.2℃, -35℃±0.2℃. The stable air pressure calibration points that can be obtained at each temperature calibration point are: 950hPa±0.03hPa, 700hPa±0.03hPa, 500hPa±0.03hPa, 200hPa±0.03hPa, 5hPa±0.03hPa. The temperature change rate of each temperature calibration point is divided into two modes, fast and slow: fast refers to the transition time from one temperature calibration point to another, with a temperature rise of about 5 minutes and a temperature drop of about 10 minutes; slow refers to the transition time from 1℃ to 3℃ to the temperature calibration point before reaching a temperature calibration point, which is about 3 minutes or longer, to ensure that the temperature of each air pressure sensor reaches the specified value. The set values ​​of the calibrated temperature point and air pressure point are adjustable, and the change rate of adjacent temperature sections is adjustable.

[0053] The present invention provides a temperature and pressure automatic calibration system for a sky detector by utilizing PLC programmable control technology, TEC temperature control technology and capacitance differential pressure instrument pressure module technology.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A temperature and pressure regulating system for an automatic air pressure calibration device, characterized in that: The temperature and pressure regulating system comprises a sealed cavity (6), wherein the cavity (6) is surrounded by at least four side walls; A temperature regulation system, the temperature regulation system comprising a semiconductor refrigeration unit (4) arranged on the outer wall of the side wall, the semiconductor refrigeration unit (4) cooling or heating according to the direction of the current passing through the semiconductor refrigeration unit (4); the semiconductor refrigeration unit (4) is formed by superimposing an outer refrigeration plate and an inner refrigeration plate, the inner refrigeration plate is in contact with the outer wall of the side wall, the heat pumping capacity of the outer refrigeration plate is higher than the heat pumping capacity of the inner refrigeration plate; the cold surface of the outer refrigeration plate is in contact with the hot surface of the inner refrigeration plate, or the hot surface of the outer refrigeration plate is in contact with the cold surface of the inner refrigeration plate; a pressure regulating system, the pressure regulating system comprising a pressure compensating device and a vacuum pump connected to the cavity, the pressure compensating device being used to pass nitrogen into the cavity to increase the pressure in the cavity, and the vacuum pump being used to extract gas from the cavity to reduce the pressure; a heat dissipation system, the heat dissipation system being in contact with the side wall; A controller, the controller being connected to the temperature regulating system, the pressure regulating system and the heat dissipation system; The pressure regulating system further comprises a capacitance differential pressure meter connected to the controller, the capacitance differential pressure meter being used to detect the air pressure in the cavity (6), and the controller controls the vacuum pump and the pressure compensation device according to the detection result of the capacitance differential pressure meter; The controller adjusts the working voltage of the outer cooling fin according to the working voltage of the inner cooling fin, and the ratio of the working voltage of the inner cooling fin to the working voltage of the outer cooling fin is consistent with a preset proportionality coefficient; One or more temperature sensors (2) are arranged in the cavity (6), and the temperature sensors (2) are connected to the controller. The controller adjusts the magnitude and direction of the current passing through the semiconductor refrigeration unit (4) according to the detection results of the temperature sensors (2); The temperature and pressure regulating system is combined with a first regulating mode as a fast mode and a second regulating mode as a slow mode. In the first regulating mode, if the temperature changes from the first temperature calibration point to the second temperature calibration point of the rising temperature, it takes 4 to 6 minutes, and if the temperature changes from the first temperature calibration point to the second temperature calibration point of the falling temperature, it takes 8 to 12 minutes; In the second adjustment mode, if the temperature difference between the temperature in the cavity and the third temperature calibration point is in the range of 1° C. to 3° C., the time required to change to the third temperature calibration point is 1 to 4 minutes.

2. The temperature and pressure regulating system according to claim 1, characterized in that: The heat dissipation system comprises a water-cooling copper pipe (3) connected to a water chiller, and the water-cooling copper pipe (3) is partially in contact with the outer wall of the side wall.

3. The temperature and pressure regulating system according to claim 2, characterized in that: The semiconductor refrigeration unit (4) is arranged between the water-cooled copper tube (3) and the side wall. There are a plurality of semiconductor refrigeration units (4). A spacing area is provided between adjacent semiconductor refrigeration units (4), and the spacing area is filled with a heat insulating material.

4. The temperature and pressure regulating system according to claim 1, characterized in that: The temperature and pressure regulation system includes at least the following five stable temperature calibration points: 40℃±0.2℃, 20℃±0.2℃, 0℃±0.2℃, -20℃±0.2℃, -35℃±0.2℃, and five stable air pressure calibration points corresponding to the five temperature calibration points: 950hPa±0.03hPa, 700hPa±0.03hPa, 500hPa±0.03hPa, 200hPa±0.03hPa, 5hPa±0.03hPa.

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