阅读说明：本技术 一种无霜高低温试验机 (Frostless high and low temperature testing machine ) 是由 刘冬喜 于 2021-08-20 设计创作，主要内容包括：本发明涉及一种无霜高低温试验机,包括箱体,设置在箱体内的试验舱、与试验舱相连的第一腔体、制冷装置、控制系统,试验舱与第一腔体之间通过进风口和出风口相连通,无霜高低温试验机还包括干燥装置、加热装置、循环风机。观察窗上设置有至少一个操作口。上述无霜高低温试验机,试验温度区间在-82～180℃,测试范围广,且能在低温下保持长时间运行,通过采用上述的箱体结构以及干燥装置,即使在低至-82℃以及大尺寸观察窗的情况下,仍能够确保试验舱及观察窗不会结霜,符合高精密工业领域对产品的老化测试要求。(The invention relates to a frost-free high-low temperature testing machine which comprises a box body, a testing cabin arranged in the box body, a first cavity connected with the testing cabin, a refrigerating device and a control system, wherein the testing cabin is communicated with the first cavity through an air inlet and an air outlet, and the frost-free high-low temperature testing machine further comprises a drying device, a heating device and a circulating fan. The observation window is provided with at least one operation opening. The frost-free high-low temperature testing machine has the advantages that the testing temperature range is-82-180 ℃, the testing range is wide, the long-time operation can be kept at the low temperature, the box body structure and the drying device are adopted, the test chamber and the observation window can be ensured not to frost even under the conditions of the temperature as low as-82 ℃ and a large-size observation window, and the aging testing requirement of the high-precision industrial field on products is met.)

1. The frostless high-low temperature testing machine is characterized in that: including box (1), set up test chamber (2) in box (1), through air intake and air outlet with first cavity (3) that test chamber (2) are linked together, right refrigerating plant (4) that test chamber (2) carry out cooling, with control system that refrigerating plant (4) are connected, setting are in on box (1) and be used for observing inside observation window (21) of test chamber (2), be provided with at least one messenger on observation window (21) the inside of test chamber (2) with the communicating operation mouth in the external world (21-1) of box (1), frostless high low temperature test machine still includes inlet end and air supply system connection and the end of giving vent to anger is connected to drying device (5) of first cavity (3), sets up and is in first cavity (3) and be used for adjusting gas temperature heating device (6), The circulating fan (7) is used for enabling gas in the test chamber (2) and the first cavity (3) to circularly flow through the air inlet and the air outlet, and the control system is connected with the drying device (5), the heating device (6) and the circulating fan (7);

the drying device (5) comprises an air inlet (53) for compressed air to enter, a first drying tower (51) and a second drying tower (52) which are respectively connected with the air inlet (53) through a first switching device (56), and an air outlet (54) which is respectively communicated with the first drying tower (51) and the second drying tower (52) and used for discharging dried compressed air, wherein molecular sieves for drying the compressed air are arranged in the first drying tower (51) and the second drying tower (52), the first drying tower (51) and the second drying tower (52) alternately dry and output the compressed air, and one of the first drying tower and the second drying tower dries the compressed air and the molecular sieve in the other drying tower;

the two ends of the first switching device (56) are respectively connected with the first drying tower (51) and the second drying tower (52), the middle part of the first switching device is communicated with the air inlet (53), a stop block (56-1) is arranged in the first switching device (56) in a sliding mode, the joint of the first switching device (56) and the first drying tower (51) is further connected with a first air hole (56-2) capable of being communicated with the outside, and the joint of the first switching device (56) and the second drying tower (52) is further connected with a second air hole (56-3) capable of being communicated with the outside; the stopper (56-1) is driven by a change in air pressure generated by opening and closing the first air hole (56-2) and the second air hole (56-3).

2. The frost-free high and low temperature testing machine according to claim 1, wherein: the box body (1) is further provided with a testing machine box door (22), and the observation window (21) is arranged on the testing machine box door (22).

3. The frost-free high and low temperature testing machine according to claim 2, wherein: the operation opening (21-1) is made of splicing pieces (21-2) made of anti-static flexible materials, and the splicing type connecting structures formed among the splicing pieces (21-2) enable the interior of the test chamber (2) and the outside of the box body (1) to be isolated from each other.

4. The frost-free high and low temperature testing machine according to claim 1, wherein: the length and the width of the observation window (21) are less than or equal to 1000mm, the thickness of the observation window is less than or equal to 100mm, and the length, the width and the height of the test chamber (2) are less than or equal to 1200 mm.

5. The frost-free high and low temperature testing machine according to claim 1, wherein: the refrigerator is characterized in that the interior of the box body (1) further comprises a second cavity (8) connected with the first cavity (3), the drying device (5) and the refrigerating device (4) are both located in the second cavity (8), and the air outlet (54) is connected with the first cavity (3).

6. The frost-free high and low temperature testing machine according to claim 1, wherein: one end of the first drying tower (51), one end of the second drying tower (52) and the air outlet (54) are communicated with each other through a second switching device (57); the two ends of the second switching device (57) are respectively connected with one end of the first drying tower (51) and one end of the second drying tower (52), the middle part of the second switching device (57) is connected with the air outlet (54), a flow limiting ring (57-1) capable of being pushed by air flow to slide is arranged in the second switching device (57), and when the control mechanism (55) is in the first working state, the flow limiting ring (57-1) slides to the end, connected with the second drying tower (52), of the second switching device (57); when the control mechanism (55) is in the second working state, the flow limiting ring (57-1) slides to one end of the second adapter device (57) connected with the first drying tower (51).

7. The frost-free high and low temperature testing machine according to claim 1, wherein: an upper filtering component (58-1), a lower filtering component (58-2) and a filling cavity (58-3) arranged between the upper filtering component (58-1) and the lower filtering component (58-2) are arranged in each of the first drying tower (51) and the second drying tower (52), the filling cavity (58-3) is used for filling molecular sieves, and a first clamping ring (58-4) used for fixing the upper filtering component is arranged between the upper filtering component (58-1) and the filling cavity (58-3); a second clamping ring (58-5) used for fixing the lower filter assembly is arranged between the lower filter assembly (58-2) and the filling cavity (58-3).

8. The frost-free high and low temperature testing machine according to claim 1, wherein: the control mechanism (55) further comprises a first control valve (55-1) for controlling the opening and closing of the first air hole (56-2), and a second control valve (55-2) for controlling the opening and closing of the second air hole (56-3).

9. The frost-free high and low temperature testing machine according to claim 8, wherein: the first control valve (55-1) and the second control valve (55-2) are both electromagnetic valves.

Technical Field

The invention relates to the technical field of aging test instruments, in particular to a frostless high-low temperature testing machine.

Background

With the improvement of the quality requirements of the recently developed industries on products, for example, data transceiving of the 5G industry and devices accessing to the 5G network need to verify reliability in a wider temperature range, and a high-low temperature testing machine is a common device for performing a simulation test on products before the products are put on the market, and is mainly used for testing the changes of the products at extremely high temperature, extremely low temperature and normal temperature and simulating the real conditions of the products used at the corresponding environmental temperature. On the other hand, the testing temperature range (-70 ℃ to 150 ℃) provided by the existing high-low temperature testing machine is not suitable for the 5G communication field and high-precision fields such as chips, aerospace elements and the like, and the existing high-low temperature testing machine has a serious frosting problem at the low temperature which can be reached by the existing high-low temperature testing machine, and if the temperature is lower than the low temperature, the frosting problem is more serious. Moreover, current high low temperature testing machine observes and operates when conveniently testing, sets up observation window and operation mouth on the box, and the setting of observation window and operation mouth has reduced the closure of test chamber to lead to the frosting problem further serious, but also lead to test temperature to accomplish lower, prior art can only minimize the size of observation window and has influenced the observation field of vision.

Therefore, a frostless high-low temperature testing machine which can be applied to product testing in the 5G communication field and high-precision fields such as chips, aerospace elements and the like is needed to be invented.

Disclosure of Invention

The invention aims to provide a frostless high-low temperature testing machine.

In order to achieve the purpose, the invention adopts the technical scheme that:

the invention provides a frostless high-low temperature testing machine which comprises a box body, a test chamber arranged in the box body, a first cavity communicated with the test chamber through an air inlet and an air outlet, a refrigerating device for cooling the test chamber, a control system connected with the refrigerating device, and an observation window arranged on the box body and used for observing the interior of the test chamber, wherein at least one operation opening enabling the interior of the test chamber to be communicated with the outside of the box body is formed in the observation window. The frostless high-low temperature testing machine further comprises a drying device, a heating device and a circulating fan, wherein the air inlet end of the drying device is connected with the air supply system, the air outlet end of the drying device is connected to the first cavity, the heating device is arranged in the first cavity and used for adjusting the temperature of air, the circulating fan is used for enabling air in the test chamber and the first cavity to circularly flow through the air inlet and the air outlet, and the control system is connected with the drying device, the heating device and the circulating fan. Under the drive of the circulating fan, gas in the test chamber circulates to the first cavity, the gas is heated by the heating device of the first cavity so as to adjust the temperature of the gas, the air in the test chamber can be kept constant at a lower temperature under the combined action of the refrigerating device and the heating device, the long-time operation of the testing machine at a low temperature of-82 ℃ and a high temperature of 180 ℃ is realized. Meanwhile, the drying device continuously conveys the dried compressed gas into the first cavity, even if a small amount of gas escapes from the operation port, the test chamber is always in a positive pressure state, and the external gas of the testing machine cannot enter the test chamber through the operation port, so that the test chamber and the observation window are ensured not to frost. The air supply system may be a device or system capable of supplying compressed air, such as a central air compression system at a production and manufacturing site.

Because the dew point, the service life and the connection structure of the common drying device can not meet the requirements of a high-low temperature testing machine, the drying device adopted by the invention comprises an air inlet for compressed air to enter, a first drying tower and a second drying tower which are respectively connected with the air inlet through a first switching device, and an air outlet which is respectively communicated with the first drying tower and the second drying tower and used for discharging dried compressed air, wherein the first drying tower and the second drying tower are respectively provided with a molecular sieve for drying the compressed air, and the first drying tower and the second drying tower alternately dry the compressed air; the two ends of the first switching device are respectively connected with the first drying tower and the second drying tower, the middle part of the first switching device is communicated with the air inlet, a stop block is arranged in the first switching device in a sliding mode, the joint of the first switching device and the first drying tower is also connected with a first air hole which can be communicated with the outside, and the joint of the first switching device and the second drying tower is also connected with a second air hole which can be communicated with the outside; the stopper is driven by the air pressure change generated by the opening and closing of the first air hole and the second air hole, the connection part of the first switching device and the first drying tower and the connection part of the first switching device and the second drying tower are alternately opened and closed through the stopper, so that the first drying tower and the second drying tower alternately dry the compressed air, one of the two drying towers dries and outputs the compressed air, and the failed molecular sieve in the other drying tower is dried and regenerated. This drying device when can reuse reach regeneration, through the control mechanism who adopts above-mentioned structure, the maximize reduces solenoid valve use quantity, is difficult for ageing, damage for drying device's long service life, work efficiency is high, has greatly simplified the tube coupling structure simultaneously, reduces the cost, saves space. On the other hand, the air dew point temperature range of the drying device is as low as-80 ℃, so that the drying device can be suitable for the manufacturing of high-precision components and the drying treatment in the testing process in more high-precision fields such as 5G communication, chips, aerospace, rail transit and the like, and the bulkhead and the observation window of the testing cabin are ensured not to frost at low temperature.

Further, still be provided with the test machine chamber door on the box, the observation window sets up on the test machine chamber door, and the operation mouth is seted up on the observation window, like this, need not to open the test machine chamber door when the operation, avoids a large amount of cooling air in the test chamber to open the escape and increase equipment energy consumption and outside air entering test chamber because of the test machine chamber door to avoid test chamber, observation window to frost. Even if a small amount of air escapes from the operation opening during operation, the air temperature in the test chamber is not affected.

Furthermore, the length, width and height of the test chamber are less than or equal to 1200mm, the length and width of the observation window are less than or equal to 1000mm, and the thickness of the observation window is less than or equal to 100mm, and within the size range, the high-low temperature testing machine can achieve frost-free effect. Compared with the prior art, the visual area of the observation window relative to the test chamber is enlarged as much as possible, the test condition in the test chamber is observed in an all-round and real-time manner, and frost-free and temperature in the chamber can be ensured.

Furthermore, the operation opening is made of anti-static flexible materials, and the splicing type connecting structures formed among the splicing pieces enable the interior of the test chamber and the exterior of the box body to be isolated from each other. The splicing positions of the splicing pieces cannot be avoided to have certain gaps, so that the isolation does not completely isolate the interior of the test chamber from the outside, but blocks the connection position of the test chamber and the outside to a certain extent.

Further, the box body is internally provided with a second cavity connected with the first cavity, the drying device and the refrigerating device are both positioned in the second cavity, and the air outlet is connected with the first cavity.

Furthermore, one end of the first drying tower, one end of the second drying tower and the air outlet are communicated with each other through a second switching device; the two ends of the second switching device are respectively connected with one end of the first drying tower and one end of the second drying tower, the middle part of the second switching device is connected with the air outlet, a flow-limiting ring capable of being pushed by air flow to slide is arranged in the second switching device, and when the control mechanism is in a first working state, the flow-limiting ring slides to one end of the second switching device connected with the second drying tower; when the control mechanism is in the second working state, the flow limiting ring slides to one end of the second adapter device connected with the first drying tower. Under the effect of current-limiting ring, only make the drying tower that the small part compressed air can get into failure, and guarantee that most compressed air can discharge to high low temperature testing machine test in the first cavity through the gas outlet and use, both handled the drying tower that became invalid, guaranteed the normal operating of high low temperature testing machine again, ensure that it reaches frostlessly, not only primary and secondary is clear but also high-efficient.

Furthermore, an upper filtering component, a lower filtering component and a filling cavity arranged between the upper filtering component and the lower filtering component are arranged in the first drying tower and the second drying tower respectively, the filling cavity is used for filling the molecular sieve, and a first clamping ring used for fixing the upper filtering component is arranged between the upper filtering component and the filling cavity; and a second clamping ring for fixing the lower filtering component is arranged between the lower filtering component and the filling cavity. Because the inside molecular sieve of drying tower can be impacted by the air current and produce the tiny particle, and the tiny particle diffuses to first switching device and second switching device along with the air current, and dog and restriction ring that can lead to block when removing, and through setting up filter assembly, lower filter assembly, can prevent the emergence of this problem effectively. On the other hand, the drying effect can be ensured, and the frostless high-low temperature testing machine can be ensured when the low-temperature testing is carried out.

Further, the control mechanism further comprises a first control valve for controlling the opening and closing of the first air hole and a second control valve for controlling the opening and closing of the second air hole. Preferably, the first control valve and the second control valve are both solenoid valves.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:

the frostless high-low temperature testing machine has the advantages that the testing temperature range is-82-180 ℃, the testing range is wide, the long-time operation can be kept at the low temperature, the box body structure and the drying device are adopted, even under the condition that the temperature is as low as-82 ℃ and the size of the observation window is large, the frosting of the test chamber and the observation window can be still avoided, and the aging testing requirement of the high-precision industrial field on products is met.

Drawings

Some specific embodiments of the invention will be described in detail hereinafter, by way of illustration and not limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

FIG. 1 is a schematic structural diagram of an embodiment of a frostless high and low temperature tester in the invention;

FIG. 2 is a cross-sectional view of the frostless high and low temperature testing machine in the embodiment of FIG. 1;

FIG. 3 is a schematic structural diagram of a drying device in the frostless high and low temperature testing machine in the embodiment shown in FIG. 1;

FIG. 4 is a cross-sectional view of FIG. 3;

fig. 5 is a schematic view of the internal structure of a drying tower of the drying apparatus of fig. 3.

Wherein the reference numerals are as follows:

1. a box body; 2. a test chamber; 21. an observation window; 21-1, an operation port; 21-2, splicing sheets; 22. a tester box door; 3. a first cavity; 4. a refrigeration device; 5. a drying device; 51. a first drying tower; 52. a second drying tower; 53. an air inlet; 54. an air outlet; 55. a control mechanism; 55-1, a first control valve; 55-2, a second control valve; 56. a first switching device; 56-1, a stop block; 56-2, a first air hole; 56-3, a second air hole; 57. a second switching device; 57-1, a flow-limiting ring; 58-1, an upper filter assembly; 58-2, a lower filter assembly; 58-3, filling the cavity; 58-4, a first snap ring; 58-5 and a second snap ring; 6. a heating device; 7. a circulating fan; 8. a second cavity.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1 to 5, the frost-free high and low temperature testing machine in this embodiment includes a box 1, a testing chamber 2 disposed in the box 1, a first chamber 3 communicated with the testing chamber 2 through an air inlet and an air outlet, a refrigerating device 4 for cooling the testing chamber 2, a control system connected to the refrigerating device 4, an observation window 21 disposed on the box 1 and used for observing the inside of the testing chamber 2, at least one operation opening 21-1 disposed on the observation window 21 and used for communicating the inside of the testing chamber 2 with the outside of the box 1, a drying device 5 having an air inlet connected to an air supply system and an air outlet connected to the first chamber 3, a heating device 6 disposed in the first chamber 3 and used for adjusting the temperature of the air, and a circulating fan 7 for circulating the air in the testing chamber 2 and the first chamber 3 through the air inlet and the air outlet, the control system is connected with the drying device 5, the heating device 6 and the circulating fan 7. Under the drive of the circulating fan 7, the gas in the test chamber 2 circulates to the first cavity 3, the gas is heated by the heating device 6 of the first cavity 3 so as to adjust the temperature of the gas, the air in the test chamber 2 can be kept constant at a lower temperature under the combined action of the refrigerating device 4 and the heating device 6, the long-time operation of the testing machine at a low temperature can be realized, the refrigerating temperature can be as low as-82 ℃, and the high temperature can be as high as 180 ℃. Meanwhile, the drying device 5 continuously conveys the dried compressed gas into the first cavity 3, even if a small amount of gas escapes from the operation opening 21-1, the test chamber 2 is always in a positive pressure state, and the external gas of the testing machine cannot enter the test chamber through the operation opening 21-1, so that the test chamber and the observation window are ensured not to frost.

The drying device in the prior art also can not satisfy the frostless test requirement of high low temperature testing machine, therefore this embodiment provides a low dew point and long service life, structure and is applicable to drying device. As shown in fig. 3 to 5, the drying device 5 in the present embodiment includes an air inlet 53 for compressed air to enter, a first drying tower 51, a second drying tower 52, and an air outlet 54 for dried compressed air to exit, each of the first drying tower 51 and the second drying tower 52 has a molecular sieve for drying compressed air, and one end of the first drying tower 51, one end of the second drying tower 52, and the air outlet 54 are communicated with each other. The drying device 5 further comprises a control mechanism 55, the control mechanism 55 comprises a first adapter 56, a first air hole 56-2 and a second air hole 56-3 which are communicated with the outside, the first adapter 56 is provided with a first channel, two ends of the first channel are respectively connected with the other end of the first drying tower 51 and the other end of the second drying tower 52, and a stop 56-1 which is arranged in the first channel in a sliding mode and driven by air pressure, one end of the first channel, which is connected with the first drying tower 51, is defined as a first end, one end of the first channel, which is connected with the second drying tower 52, is defined as a second end, the air inlet 53 is communicated with the middle part of the first channel, the first end is also communicated with the first air hole 56-2, and the second end is also communicated with the second air hole 56-3. The control mechanism 55 has at least two operating states and is switched by opening and closing the first air hole 56-2 and the second air hole 56-3; when the first air hole 56-2 is closed and the second air hole 56-3 is opened, the control mechanism 55 is in its first working state, the stopper 56-1 abuts against the second end of the first channel, so that the air inlet 53 and the other end of the second drying tower 52 are blocked, and the other end of the first drying tower 51 is communicated with the air inlet 53, the first drying tower 51 dries and outputs the compressed air, and simultaneously the first drying tower 51 transmits the dried compressed air to the second drying tower 52 to dry the molecular sieve in the second drying tower 52; when the second air hole 56-3 is closed and the first air hole 56-2 is opened, the control mechanism 55 is in its second working state, the stopper 56-1 abuts against the first end of the first channel, so that the air inlet 53 and the other end of the first drying tower 51 are blocked, the other end of the second drying tower 52 is communicated with the air inlet 53, the second drying tower 52 dries and outputs the compressed air, and simultaneously the second drying tower 52 transmits the dried compressed air to the first drying tower 51 to dry the molecular sieve in the first drying tower 51.

The control mechanism 55 realizes the specific principle of switching the working states by opening and closing the first air hole 56-2 and the second air hole 56-3: in an initial state, taking a first working state as an example, as shown in fig. 4, the first air hole 56-2 is closed, the second air hole 56-3 is opened, the stopper 56-1 is located at the second end of the first channel, the compressed air flows into the first drying tower 51 through the first end of the first channel via the air inlet 53, and flows out from the air outlet 54 after being dried, and meanwhile, part of the dried air flows into the second drying tower 52 to dry the molecular sieve therein, and is then discharged through the second air hole 56-3. The air pressure at the other end of the first drying tower 51 (i.e., the bottom end of the first drying tower 51 shown in fig. 4) is greater than the normal atmospheric pressure due to the continuous air intake from the air intake 53 and the obstruction of the air flow by the molecular sieves in the first drying tower 51; meanwhile, since the molecular sieve in the second drying tower 52 obstructs the air flow and the second air hole 56-3 is open to the outside atmosphere, the air pressure at the other end of the second drying tower 52 (i.e., the bottom end of the second drying tower 52 shown in fig. 4) is substantially equal to the normal atmospheric pressure, which results in the air pressure at the left side of the block 56-1 being greater than the air pressure at the right side thereof (where the left side and the right side of the block 56-1 are defined as illustrated in fig. 4), thereby pressing the block 56-1 against the second end of the passage and blocking the second drying tower 52 so that the compressed air cannot enter. During switching, the first air hole 56-2 is opened, the second air hole 56-3 is closed, and at the moment after switching, the first air hole 56-2 is communicated with the outside atmosphere, so that the pressure of the first drying tower 51 is released instantly. Meanwhile, the airflow enters the second drying tower 52 from one end of the second drying tower 52 (i.e., the top end of the second drying tower 52 shown in fig. 4), so that the air pressure in the second drying tower 52 rises, and the air flow in the second drying tower 52 is stagnated due to the closing of the second air hole 56-3, so that the air flow rate on the right side of the stopper 56-1 is close to 0, and because the air flow rate is inversely proportional to the pressure generated by the air flow rate (bernoulli's theorem), a pressure difference is generated between the left side and the right side of the stopper 56-1, so that the pressure on the right side is greater than the pressure on the left side thereof, so that the stopper 56-1 slides leftwards and pushes to the first end of the first channel, and the bottom end of the first drying tower 51 is blocked. In the process that the stopper 56-1 is separated from the right side and moves leftwards, gas can enter the second drying tower 52 through the right side, but because the top end of the second drying tower 52 still has gas entering, and the molecular sieve in the second drying tower 52 blocks the gas flow, the gas pressure at the bottom end of the second drying tower 52 is further increased, the gas flow rate at the right side of the stopper 56-1 is always smaller than that at the left side, so that the stopper 56-1 can move leftwards conveniently until the stopper 56-1 is abutted against the first end of the first channel, and the bottom end of the first drying tower 51 is blocked. Through the control mechanism 55 adopting the structure, when the drying device 5 can be recycled to achieve regeneration, the use number of the electromagnetic valves is reduced to the maximum, the service life is long, the electromagnetic valves are not easy to age and damage, the working efficiency is high, meanwhile, the pipeline connection structure is greatly simplified, the cost is reduced, the space is saved, the air dew point temperature range of the drying device is as low as minus 80 ℃, and the test requirements of a high-low temperature testing machine on high-precision components in more high-precision fields such as 5G communication, chips, aerospace, rail transit and the like can be met.

In a more preferred embodiment, the drying device 5 further comprises a second adapter 57, one end of the first drying tower 51, one end of the second drying tower 52 and the air outlet 54 are communicated with each other through the second adapter 57, specifically, as shown in fig. 3 and fig. 4, two ends of the second adapter 57 are respectively connected with one end of the first drying tower 51 and one end of the second drying tower 52, a middle portion of the second adapter 57 is connected with the air outlet 54, a flow limiting ring 57-1 capable of being pushed by the air flow to slide is arranged in the second adapter 57, and when the control mechanism 55 is in the first working state, the flow limiting ring 57-1 slides to the end of the second adapter 57 connected with the second drying tower 52; when the control means 55 is in its second operating state, the restrictor ring 57-1 is slid to the end of the second adapter 57 that is connected to the first drying tower 51. Through setting up current-limiting ring 57-1, only a small part gets into the drying tower that became invalid in the gas after making the drying, guarantee that most dry back gas is discharged to high low temperature test box test in first cavity 3 through gas outlet 54 and is used, both handled the drying tower that became invalid, guaranteed the normal operating of high low temperature test machine again, guarantee that it reaches no frost, not only primary and secondary is clear but also high-efficient. In addition, the second switching device 57 in this embodiment does not need to be controlled by a solenoid valve, and as the air flow directions of the first drying tower 51 and the second drying tower 52 are changed after the working state of the control mechanism 55 is switched, the position of the restrictor ring 57-1 is automatically changed by being pushed by the air flow, and in the process of switching the working state of the control mechanism 55, the restrictor ring 57-1 does not have any influence on the change of the air flow direction.

Preferably, as shown in fig. 5, an upper filter assembly 58-1, a lower filter assembly 58-2 and a filling cavity 58-3 arranged between the upper filter assembly 58-1 and the lower filter assembly 58-2 are arranged inside each of the first drying tower 51 and the second drying tower 52, the filling cavity 58-3 is used for filling molecular sieves, and a first snap ring 58-4 for fixing the upper filter assembly is arranged between the upper filter assembly 58-1 and the filling cavity 58-3; a second snap ring 58-5 for securing the lower filter assembly is disposed between the lower filter assembly 58-2 and the fill chamber 58-3. The molecular sieve can be limited in the drying tower by the internal structure of the drying tower, small particles generated by the impact of the airflow on the molecular sieve are prevented from being blocked when the stop block and the flow limiting ring move due to the fact that the small particles are diffused into the first switching device 56 and the second switching device 57 along with the airflow, the normal operation of the device is ensured, and the normal work of the high-low temperature test box is ensured. On the other hand, the problem of molecular sieve leakage is solved, so that the drying effect of the molecular sieve is ensured, and low dew point drying is kept, so that the frostless condition of the high-low temperature test box in the low-temperature test process is ensured.

Preferably, the control mechanism 55 controls the opening and closing of the first air hole 56-2 and the second air hole 56-3 through the first control valve 54 and the second control valve 55, respectively, in this embodiment, the first control valve 54 and the second control valve 55 are both solenoid valves, when the solenoid valve of the first control valve 54 is opened, the compressed air in the first drying tower 51 is discharged from the first air hole 56-2 to the outside, and when the solenoid valve is closed, the first air hole 56-2 is closed. Similarly, when the solenoid valve of the second control valve 55 is opened, the compressed air in the second drying tower 52 is discharged to the outside through the second air hole 56-3, and when the solenoid valve is closed, the second air hole 56-3 is closed. The first air hole 56-2 and the second air hole 56-3 are respectively controlled by different devices, so that the accuracy of control operation is improved. In practical applications, the first control valve 54 and the second control valve 55 may be other devices or apparatuses capable of controlling the opening and closing of the air vent in the prior art, and are not limited to solenoid valves. It can be seen that the drying device 5 in this embodiment requires only a maximum of two solenoid valves.

The box body 1 in the embodiment is further provided with a testing machine box door 22, and the observation window 21 is arranged on the testing machine box door 22, so that the testing machine box door 22 does not need to be opened during operation, and the phenomenon that a large amount of cooling air in the test chamber 2 is leaked due to the opening of the testing machine box door 22 to increase the energy consumption of equipment and the external air enters the test chamber 2 is avoided, so that the test chamber 2 and the observation window 21 are prevented from frosting. Even if a small amount of air escapes from the operation port 21-1 during operation, the air temperature in the test chamber 2 is not affected.

In the embodiment, the length, width and height of the test chamber 2 are less than or equal to 1200mm, the length and width of the observation window 21 are less than or equal to 1000mm, and the thickness is less than or equal to 100 mm. Compared with the prior art, the visual area of the observation window 21 relative to the test chamber 2 is enlarged as much as possible, so that the test condition in the test chamber 2 can be observed in all directions and in real time, and frost-free and temperature in the chamber can be ensured.

In a more preferred embodiment, the operation opening 21-1 is made of a splicing sheet 21-2 made of antistatic flexible material, and the inside of the test chamber 2 is isolated from the outside of the box body 1 by a splicing connection structure formed among a plurality of splicing sheets 21-2. The joints of the splicing pieces 21-2 are inevitably provided with gaps, so that the isolation does not completely isolate the interior of the test chamber 2 from the outside, but rather blocks the connection of the test chamber 2 to the outside to a certain extent.

The refrigerating device 4, the heating device 6, the circulating fan 7 and the control system in the embodiment all adopt devices which can achieve corresponding effects in the prior art, and therefore the structures of the devices are not described in detail herein.

The frostless high-low temperature testing machine in the embodiment has the testing temperature range of-82-180 ℃, has a wide testing range, can keep running for a long time at low temperature, can still ensure that the testing chamber and the observation window do not frost even under the conditions of low temperature of-82 ℃ and large-size observation window by adopting the box body structure and the drying device, and meets the aging testing requirement of the high-precision industrial field on products.

The above embodiments are merely illustrative of the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the content of the present invention and implement the invention, and not to limit the scope of the invention, and all equivalent changes or modifications made according to the spirit of the present invention should be covered by the scope of the present invention.