CN206817841U - A kind of novel energy-conserving liquid nitrogen refrigerating system - Google Patents

Abstract

The utility model discloses a novel energy-saving liquid nitrogen refrigeration system, which comprises a self-pressurized liquid nitrogen tank, a filter, a high-frequency pulse electromagnetic valve, a capillary, a test chamber working room and a controller, and a temperature sensor is installed in the test box working room. device. The working chamber of the test box includes a box body, a door body and a sealing structure. The sealing structure includes graphite PTFE sealing packing, silica gel sealing packing and self-limiting temperature heating belt. Fluorine sealing packing and silicone sealing packing are installed on the door body and located outside the connection gap. The utility model can control the time of turning on and off the nitrogen gas in one cycle, keep the temperature in the working chamber of the test box constant, reduce the consumption of liquid nitrogen, and does not need the heating balance of the heater, reduces the energy consumption, and the test box works at the same time The inner and outer double-layer seals of graphite PTFE sealing packing and silica gel sealing packing are used in the chamber, which can effectively achieve the sealing effect at low temperature and reduce energy consumption.

Description

A New Energy-saving Liquid Nitrogen Refrigeration System

technical field

The utility model relates to the technical field of environmental test equipment, in particular to a novel energy-saving liquid nitrogen refrigeration system.

Background technique

In the low-temperature test of environmental test equipment, the general mechanical refrigeration single stage can reach about -40°C, the double stage refrigeration can reach about -80°C, and the three stage refrigeration can reach about -120°C. If a lower temperature test is required, liquid nitrogen refrigeration is required to meet the requirements. The minimum liquid nitrogen refrigeration can reach -190°C or lower, and the evaporation temperature of liquid nitrogen under normal pressure is -196°C. Theoretically, the test chamber can be obtained A temperature close to -196°C.

Due to the development of science and technology and scientific experiments, the temperature requirements of various scientific research units and military enterprises are becoming more and more stringent, and the low temperature requirements must be below -100°C, up to -190°C. For conventional liquid nitrogen refrigeration systems, please refer to Figure 1 and Figure 1. 2. Work by self-pressurized liquid nitrogen tank 1', filter 2', first solenoid valve 3', second solenoid valve 4', first capillary 5', second capillary 6', pipe 7' and experiment box Chamber 8', the self-pressurized liquid nitrogen tank 1', filter 2', first solenoid valve 3', first capillary 5' form the first connection line with the test chamber working room 8' through the pipeline 7' . The self-pressurized liquid nitrogen tank 1', the filter 2', the second solenoid valve 4', and the second capillary 6' form a second connection line with the test chamber working room '8 through the pipeline 7', wherein the first capillary The flow rate of 5' is greater than that of the second capillary 6'. Its working principle is as follows: liquid nitrogen at a certain pressure is delivered from the pressurized liquid nitrogen tank 1', passes through the filter 2', the first solenoid valve 3', and after throttling and depressurizing through the first capillary tube 5' with a large flow rate, the liquid nitrogen Nitrogen will evaporate and cool down in the working chamber 8' of the experimental box, and the liquid nitrogen will continue to output, and the temperature will continue to drop. When the temperature drops to the required low temperature, the control system controls the first solenoid valve 3' to close, and the second solenoid valve 4' is opened, and after throttling by the second capillary tube 6' with a small flow rate, it enters the test chamber working chamber 8' to evaporate and cool down, but its flow rate cannot be precisely controlled. The electric heater 9' in the working chamber 8' is heated to balance the cooling capacity of the liquid nitrogen, thereby achieving temperature stability. When the temperature in the working room 8' of the test box is at a low temperature of -100°C to -190°C, if the working room 8 of the test box is sealed with a conventional double-layer silicone rubber sealing strip 10' and a door frame heating belt 11' to preheat, The lowest temperature that the silicone rubber sealing strip 10' can withstand is above -80°C, and if it is lower than -80°C, the silicone rubber sealing strip 10' will become hard and brittle, and lose the sealing effect.

To sum up, the conventional liquid nitrogen refrigeration system has the following problems:

1. After the second capillary 6' is throttled, its flow rate cannot be precisely controlled. Therefore, if you want to keep the temperature constant, you need to heat it through the electric heater 9' installed in the working chamber 8' of the test chamber to balance the liquid. The refrigeration capacity of nitrogen, so liquid nitrogen needs to be continuously output, which will cause a large amount of liquid nitrogen consumption. When the temperature is constant, electric heating is required to balance, which in turn increases energy consumption.

2. Since the best sealing temperature of the silicone sealing packing 10' is -70°C, it has good flexibility, good air tightness, and good sealing effect. Adding the heating belt door frame preheating function can make the sealing temperature of the silicone rubber sealing strip the highest It can reach -100°C. Therefore, the conventional silicone sealing packing 10' sealing method in the working room 8' of the test chamber can no longer meet its sealing requirements. Due to the large preheating power of the heating belt and door frame, there is considerable Part of the cooling capacity is consumed in preheating, which wastes energy, and the sealing effect is not very good, causing cold air to leak out, causing frost, ice, and condensation between the door frame and the door.

Utility model content

In view of the above deficiencies, the purpose of this utility model is to provide a new type of energy-saving liquid nitrogen refrigeration system, which transmits the signal to the high-frequency pulse solenoid valve through the temperature sensor sensing the temperature change in the working room of the test chamber and controls the opening and closing within one cycle The nitrogen time keeps the temperature in the working chamber of the test chamber constant, reduces the consumption of liquid nitrogen, and does not require a heater to balance the heating, which reduces energy consumption. At the same time, the working chamber of the test chamber adopts graphite PTFE sealing packing and silica gel The inner and outer double-layer sealing of the sealing packing can effectively achieve the sealing effect at low temperature, improve the sealing effect of the working chamber of the test chamber, and reduce energy consumption.

In order to achieve the above object, the technical solution provided by the utility model is:

A new energy-saving liquid nitrogen refrigeration system includes a self-pressurized liquid nitrogen tank, a filter, a high-frequency pulse solenoid valve, a capillary tube, a test chamber working chamber and a controller. The self-pressurized liquid nitrogen tank, filter, high-frequency pulse solenoid valve and capillary tube are sequentially connected through pipelines and connected to the working chamber of the test box, and a temperature sensor is installed in the working room of the test box. The working chamber of the test box includes a box body, a door body and a sealing structure, and the door body is hinged to the box body through a hinge. The sealing structure is arranged at the connection gap between the box body and the door body. The sealing structure includes graphite PTFE sealing packing, silica gel sealing packing and self-limiting temperature heating belt. The box body and the door body are connected The inner side of the gap is correspondingly provided with the graphite PTFE sealing packing, the silica gel sealing packing is installed on the door body and is located outside the connection gap, and the self-limiting temperature heating belt is arranged on the silica gel sealing packing on the box and door. The high-frequency pulse solenoid valve and temperature sensor are electrically connected to the controller.

Preferably, the box body is enclosed by the box outer frame and the box inner frame, and the junction of the box outer frame and the box inner frame is recessed upwards to form an installation groove, and the graphite tetrafluoro sealing packing is installed In the installation groove, the door body is enclosed by the outer frame of the door and the inner frame of the door, and the connection between the outer frame of the door and the inner frame of the door is recessed downward to form an installation groove, and the graphite PTFE sealing packing is installed In the installation groove, when the door body is closed, the graphite PTFE sealing packing installed in the box and the graphite PTFE sealing packing installed in the door contact each other and squeeze together.

Preferably, the box body and the door body are respectively provided with insulation layers.

Preferably, the sealing structure further includes a plurality of heat insulation boards, the heat insulation boards are provided between the joints of the outer frame of the box and the inner frame of the box, and the joints of the outer frame of the door and the inner frame of the door The heat insulation board is arranged between.

Preferably, the connection between the box body and the door body is set in a stepped shape, including a first platform and a second platform from the inside to the outside, the graphite PTFE sealing packing is arranged on the first platform, and the self-limiting temperature The heating belt and the silicone sealing packing are set on the second platform.

The beneficial effects of the utility model are:

1. The utility model detects the temperature change in the working chamber of the test chamber through the temperature sensor installed in the working chamber of the test chamber, and transmits the signal to the controller to control the high-frequency pulse solenoid valve to control the opening time and the opening time of the nitrogen gas within a certain period. The closing time is used to control the flow of liquid nitrogen into the working chamber of the test chamber, so as to achieve the purpose of constant temperature in the working chamber of the test chamber, reduce the consumption of liquid nitrogen, and do not need a heater for heating balance, reducing energy consumption;

2. The graphite PTFE sealing packing used in the working room of the test chamber can withstand the lowest temperature of -200°C and maintain flexibility without becoming brittle and hard. Therefore, the graphite PTFE sealing packing is used as the first layer The sealing structure can block most of the cold air leakage in the test chamber, so that the temperature on the outside of the connecting gap on both sides of the box and the door body can be increased to above -80°C, and then sealed by the silicone sealing packing arranged on the outside, and passed through The self-limiting temperature heating belt is heated, and the temperature on the outside can reach the optimum sealing temperature of the normal silicone sealing packing. Therefore, the utility model adopts the double-layer sealing design of the graphite PTFE sealing packing and the silicone sealing packing, and can be used at low temperature. Under certain conditions, it can effectively ensure the sealing performance of the box body and the door body, improve the sealing effect of the test chamber working room, and reduce energy consumption.

Below in conjunction with accompanying drawing and embodiment, the utility model is further described.

Description of drawings

The accompanying drawings are used to provide a further understanding of the utility model, and constitute a part of the description, together with the following specific embodiments, are used to explain the utility model, but do not constitute a limitation to the utility model. In the attached picture:

Fig. 1 is a structural schematic diagram of a liquid nitrogen refrigeration system in the prior art.

Fig. 2 is an enlarged view of the silica gel sealing packing of the liquid nitrogen refrigeration system shown in Fig. 1 .

Fig. 3 is a structural schematic diagram of a novel energy-saving liquid nitrogen refrigeration system of the present invention.

Fig. 4 is an enlarged view of the sealing structure of a novel energy-saving liquid nitrogen refrigeration system shown in Fig. 3 .

Each reference numeral in the figure is explained as follows.

Self-pressurized liquid nitrogen tank - 1', filter - 2', first solenoid valve - 3', second solenoid valve - 4', first capillary - 5', second capillary - 6', pipeline - 7' , Experimental box studio - 8', electric heater - 9', silica gel sealing packing - 10', self-pressurized liquid nitrogen tank - 1, filter - 2, high frequency pulse solenoid valve - 3, capillary - 4, Test chamber studio—5, chamber body—51, chamber outer frame—511, chamber inner frame—512, door body—52, door outer frame—521, door inner frame—522, sealing structure—53, graphite PTFE Sealing packing—531, silicone sealing packing—532, self-limiting heating belt—533, heat shield—534, hinge—54, pipe—6, temperature sensor—7, insulation layer—8, first platform— 9. The second platform—10.

detailed description

In order to describe the technical content, structural features, achieved goals and effects of the present utility model in detail, the following will be described in detail in conjunction with the embodiments and accompanying drawings.

The technical solutions of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are part of the embodiments of the utility model, but not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model. In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" The orientation or positional relationship indicated by etc. is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, use a specific The azimuth structure and operation, therefore can not be construed as the limitation of the present utility model.

Please refer to Figure 3 and Figure 4, a new type of energy-saving liquid nitrogen refrigeration system, including a self-pressurized liquid nitrogen tank 1, a filter 2, a high-frequency pulse solenoid valve 3, a capillary tube 4, a test chamber working chamber 5 and a controller. The self-pressurized liquid nitrogen tank 1, the filter 2, the high-frequency pulse solenoid valve 3 and the capillary 4 are sequentially connected through the pipeline 6 and connected to the working chamber 5 of the test chamber, and the working chamber 5 of the test chamber is equipped with The temperature sensor 7 is used to detect the temperature change in the working chamber 5 of the test chamber, and transmit the signal to the controller to control the high-frequency pulse solenoid valve 3 to control the opening time and closing time of nitrogen gas within a certain period to achieve the control of liquid nitrogen Into the flow in the working chamber 5 of the test chamber, so as to achieve the purpose of constant temperature in the working chamber 5 of the test chamber. The working chamber 5 of the test box includes a box body 51 , a door body 52 and a sealing structure 53 , and the door body 52 is hinged to the box body 51 through a hinge 54 . The sealing structure 53 is arranged at the connection gap between the box body 51 and the door body 52. The sealing structure 53 includes a graphite tetrafluoro sealing packing 531, a silica gel sealing packing 532 and a self-limiting temperature heating belt 533. The inner side of the connecting gap between the box body 51 and the door body 52 is correspondingly provided with the graphite tetrafluoro sealing packing 531. When the door body 52 is closed, the graphite tetrafluoro sealing packing 531 installed in the box body 51 is connected with the door The graphite tetrafluoro sealing packing 531 installed in the body 52 is in contact with each other and squeezed together to seal the inside and outside of the working chamber 5 of the test chamber. In this embodiment, the graphite tetrafluoro material can withstand a minimum temperature of -200°C and maintain flexibility without becoming brittle and hard, thus ensuring the sealing effect. The silicone sealing packing 532 is installed on the door body 52 and is located outside the connection gap, and the self-limiting temperature heating belt 533 is arranged on the box body 51 and the door body 52 at the silicone sealing packing 532 . In this embodiment, because the material of the graphite tetrafluoro sealing packing 531 in the inner layer is relatively elastic and airtight, the graphite tetrafluoro sealing packing 531 is used as the first layer of sealing structure, which can block the working chamber 5 Most of the cold air inside leaks, making the temperature on the outside of the connection gap on both sides of the box body 51 and the door body 52 rise to above -80°C, and then it is sealed by the silicone sealing packing 532 arranged on the outside, and heated by self-limiting temperature The belt 533 is heated, and the temperature on the outside can reach the optimum sealing temperature of the normal silica gel sealing packing 532. Therefore, the utility model adopts the double-layer sealing design of the graphite tetrafluoro sealing packing 531 and the silica gel sealing packing 532. Under certain conditions, the sealing performance of the box body 51 and the door body 52 can be effectively guaranteed. The high-frequency pulse solenoid valve 3 and the temperature sensor 7 are electrically connected to the controller.

Specifically, the box body 51 is surrounded by a box outer frame 511 and a box inner frame 512, and the junction of the box outer frame 511 and the box inner frame 512 is recessed upward to form an installation groove, and the graphite tetrafluoroethylene The sealing packing 531 is installed in the installation groove. The door body 52 is enclosed by a door outer frame 521 and a door inner frame 522, and the junction of the door outer frame 521 and the door inner frame 522 is recessed downward to form an installation groove, and the graphite tetrafluoro sealing packing 531 is installed Set in the installation groove. When the door body 52 is closed, the graphite PTFE sealing packing 531 installed in the box body 51 and the graphite PTFE sealing packing 531 installed in the door body 52 contact each other and squeeze together to achieve the first layer of sealing effect .

In this embodiment, the box body 51 and the door body 52 are respectively provided with an insulating layer 8, which isolates the transmission of the internal temperature and the external temperature of the box inspection studio 5, and is used to ensure the internal temperature of the box inspection studio 5 to prevent Consumption of air conditioning.

Further, the sealing structure 53 also includes a plurality of heat insulation boards 534, and the heat insulation boards 534 are provided between the joints of the box outer frame 511 and the box inner frame 512, and the door outer frame 521 and the box inner frame 512 are connected. The heat insulation board 534 is provided between the joints of the door inner frame 522 , which reduces the heat transfer between the box outer frame 511 and the box inner frame 512 and the heat transfer between the door outer frame 521 and the door inner frame 522 .

In this embodiment, the connection between the box body 51 and the door body 52 is set in a stepped shape, including the first platform 9 and the second platform 10 from the inside to the outside, and the graphite tetrafluoro sealing packing 531 is arranged on the first platform. On the platform 9 , the self-limiting temperature heating belt 533 and the silica gel sealing packing 532 are arranged on the second platform 10 .

The working principle of the utility model: the liquid nitrogen of a certain pressure is delivered from the pressurized liquid nitrogen tank 1, passes through the filter 2, the high-frequency pulse electromagnetic valve 3, and after the capillary 4 throttles and reduces the pressure, the liquid nitrogen is in the box inspection studio 5 Evaporation and cooling, the continuous output of liquid nitrogen, the temperature will continue to drop, when the temperature drops to the required low temperature, the temperature sensor 7 will detect the temperature change in the working chamber 5 of the test chamber, and transmit the signal to the controller to control the high temperature. The high-frequency pulse solenoid valve 3 performs opening/closing actions in a fixed cycle, and controls the time length of the high-frequency pulse solenoid valve 3 opening or closing in one cycle, so as to control the flow of liquid nitrogen entering the box inspection studio 5, thereby To achieve the purpose of constant temperature. And through the double-layer sealing design of the graphite tetrafluoro sealing packing 531 and the silica gel sealing packing 532, the sealing performance of the box body 51 and the door body 52 can be effectively guaranteed under low temperature conditions.

According to the disclosure and teaching of the above specification, those skilled in the art to which the present utility model belongs can also change and modify the above embodiment. Therefore, the utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the utility model should also fall within the scope of protection of the claims of the utility model. In addition, although some specific terms are used in this specification, these terms are only for convenience of description, and do not constitute any limitation to the present invention. The use of other devices identical or similar thereto is within the protection scope of the present invention.

Claims (5)

1. A new type of energy-saving liquid nitrogen refrigeration system, characterized in that it includes a self-pressurized liquid nitrogen tank (1), a filter (2), a high-frequency pulse solenoid valve (3), a capillary tube (4), and a test chamber working room (5) and the controller, the self-pressurized liquid nitrogen tank (1), filter (2), high-frequency pulse solenoid valve (3) and capillary (4) are connected in sequence through the pipeline (6) and connected to the test In the box working room (5), and the temperature sensor (7) is provided in the test box working room (5), the test box working room (5) includes a box body (51), a door body (52) and A sealing structure (53), the door body (52) is hinged on the box body (51) through a hinge (54), and the sealing structure (53) is arranged on both sides of the box body (51) and the door body (52) At the connection gap, the sealing structure (53) includes graphite tetrafluoro sealing packing (531), silica gel sealing packing (532) and self-limiting temperature heating belt (533), the box body (51) and the door body (52) The inside of the connection gap is correspondingly provided with the graphite tetrafluoro sealing packing (531), and the silica gel sealing packing (532) is installed on the door body (52) and is located outside the connection gap, The self-limiting temperature heating belt (533) is arranged on the box body (51) and the door body (52) at the silica gel sealing packing (532), and the high-frequency pulse electromagnetic valve (3) and temperature sensor (7 ) is electrically connected to the controller. 2. A new type of energy-saving liquid nitrogen refrigeration system according to claim 1, characterized in that: the box (51) is enclosed by a box outer frame (511) and a box inner frame (512), and The junction of the box outer frame (511) and the box inner frame (512) is recessed upwards to form an installation groove, and the graphite tetrafluoro sealing packing (531) is installed in the installation groove, and the door body (52) is formed by The outer frame of the door (521) and the inner frame of the door (522) are enclosed, and the connection between the outer frame of the door (521) and the inner frame of the door (522) is recessed downward to form an installation groove, and the graphite tetrafluoro sealed packing (531) is installed in the installation groove. When the door body (52) is closed, the graphite PTFE sealing packing (531) installed in the box (51) and the graphite PTFE installed in the door (52) will The sealing packing (531) contacts and squeezes together. 3. A new type of energy-saving liquid nitrogen refrigeration system according to claim 2, characterized in that: the box body (51) and the door body (52) are respectively provided with insulation layers (8). 4. A new type of energy-saving liquid nitrogen refrigeration system according to claim 2, characterized in that: the sealing structure (53) also includes a plurality of heat insulation boards (534), and the box outer frame (511) and The heat insulation board (534) is provided between the connection of the box inner frame (512), and the heat insulation board (534) is provided between the connection of the door outer frame (521) and the door inner frame (522). 534). 5. A new type of energy-saving liquid nitrogen refrigeration system according to claim 1, characterized in that: the connection between the box body (51) and the door body (52) is set in a stepped shape, including the first platform from the inside to the outside (9) and the second platform (10), the graphite tetrafluoro sealing packing (531) is arranged on the first platform (9), the self-limiting temperature heating belt (533) and the silica gel sealing packing (532) Set on the second platform (10).