Vacuum drying oven system and drying rate control method thereof

Abstract

The present application provides a kind of vacuum drying oven system and its drying rate control method, vacuum drying oven system includes: the box of vacuum drying oven;Condenser pipeline is connected with box;With the condenser pipeline connection of box and inner circulation pipeline;With the inner circulation pipeline connection of air inlet pipe;With the ultrasonic atomization device of box connection;Ultrasonic atomization device is sprayed into the first volume of solvent atomized solvent obtained after atomization in the box, and the evaporation of atomized solvent makes the solvent vapor in the box reach saturated vapor pressure;First volume is greater than preset value;By controlling condenser pipeline, inner circulation pipeline and air inlet pipe, the condensation of solvent vapor in the box and the evaporation of solvent in the process of inner circulation, control the drying rate of sample solvent.The scheme of the present application can realize the accurate control of solvent atmosphere and solvent evaporation rate in the box of drying oven, with low cost, good uniformity, high efficiency and time saving.

Description

Technical Field

[0001] This invention relates to the field of drying oven technology, and in particular to a vacuum drying oven system and its drying rate control method. Background Technology

[0002] Vacuum drying ovens are specifically designed for drying heat-sensitive, easily decomposed, and easily oxidized substances. They can be filled with inert gas, enabling rapid drying of even complex compositions. Vacuum drying ovens are widely used in research and application fields such as biochemistry, chemical pharmaceuticals, medical and health care, agricultural research, and environmental protection, for powder drying, baking, and sterilization of various glass containers. They are particularly suitable for the rapid and efficient drying of heat-sensitive, easily decomposed, easily oxidized substances, and items with complex compositions.

[0003] Existing vacuum drying ovens cannot control the evaporation rate of solvents inside the oven, and therefore cannot meet the requirements when precise control of the solvent evaporation rate is needed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a vacuum drying oven system and a drying rate control method thereof, which solves the problem that the evaporation rate of the solvent in the oven cannot be controlled in the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A vacuum drying oven system, comprising: The body of the vacuum drying oven; The condenser pipes connected to the housing; An internal circulation pipeline connected to the housing and the condensate pipeline; The air intake pipe connected to the internal circulation pipeline; An ultrasonic atomizing device connected to the housing; The ultrasonic atomizing device sprays a first volume of solvent into the chamber, and the atomized solvent is then atomized. The atomized solvent evaporates, causing the solvent vapor in the chamber to reach saturated vapor pressure. The first volume is greater than a preset value. By controlling the condensation pipe, the internal circulation pipe, and the air inlet pipe, the condensation of the solvent vapor in the chamber and the solvent evaporation during the internal circulation process are controlled, thereby controlling the drying rate of the sample solvent.

[0006] Optionally, during the condensation process, the gas in the chamber enters the condensation pipeline through the exhaust port, and the condensation pipeline condenses the gas. During the internal circulation process, the condensed gas is transported to the air inlet pipe through the internal circulation pipeline, and the air inlet pipe transports the gas from the internal circulation pipeline into the box through the air inlet. The condensation process and the internal circulation process alternate.

[0007] Optionally, the air inlet is located at a first position on the back of the housing, and the exhaust port is located at a second position on the back of the housing, with the first position and the second position being vertically aligned.

[0008] Optionally, the box body is provided with a first inner liner hanging plate, the first inner liner hanging plate and the inner wall of the back where the air inlet and the exhaust port are located form a first accommodating space, the air inlet and the exhaust port and the atomizing gas inlet of the ultrasonic atomizing device are located in the first accommodating space; the first inner liner hanging plate has evenly distributed vent holes.

[0009] Optionally, the air inlet is located on the first side of the housing, and the exhaust outlet is located on the second side of the housing. The first side and the second side are two opposite sides of the housing, and the air inlet and the exhaust outlet are located on the same horizontal line.

[0010] Optionally, the box body is provided with a second inner liner hanging plate and a third inner liner hanging plate; The second inner liner mounting plate and the inner wall of the first side where the air inlet is located form a second receiving space; the air inlet is located in the second receiving space; The third inner liner mounting plate and the inner wall of the second side where the exhaust port is located form a third receiving space; the exhaust port is located in the third receiving space; The second inner liner hanging plate and the third inner liner hanging plate have evenly distributed ventilation holes.

[0011] Embodiments of the present invention also provide a method for controlling the drying rate of a vacuum drying oven, comprising: Place the sample solvent to be dried into the vacuum drying oven; The atomized solvent, obtained by spraying a first volume of solvent into the chamber through an ultrasonic atomizing device, evaporates, causing the solvent vapor inside the chamber to reach saturated vapor pressure; the first volume is greater than a preset value. The drying rate of the sample solvent is controlled by controlling the condensation of solvent vapor inside the vacuum drying oven and the evaporation of solvent during the internal circulation process.

[0012] Optionally, the ultrasonic atomizing device includes: an ultrasonic head, a storage tank, and an atomizing tube connecting the storage tank and the housing; A first volume of atomized solvent is sprayed into the chamber via an ultrasonic atomizing device, comprising: The solvent in the storage tank is atomized into atomized solvent using an ultrasonic head; High-pressure air is forced into the storage tank through an external air compressor and air pipes, and atomized solvent is forced into the housing through the atomizing pipe.

[0013] Optionally, controlling the condensation of solvent vapor inside the vacuum drying oven and the solvent evaporation during the internal circulation process includes: The condenser pipe and the air inlet pipe connected to the oven body are opened alternately by controlling the solenoid valve to alternately connect the condenser pipe and the internal circulation pipe. During the condensation circulation, the solvent vapor in the oven body enters the condenser pipe for condensation treatment, and then enters the air inlet pipe through the internal circulation pipe. The solvent vapor condenses and liquefies in the condenser pipe, and the solvent vapor content in the oven body decreases. During the internal circulation, the solvent vapor in the oven body enters the internal circulation pipe and re-enters the oven body through the internal circulation pipe, causing the solvent in the oven to evaporate.

[0014] Optionally, the condensation treatment of the condensation pipeline includes: After the set condensation period, the first solenoid valve of the condensation pipeline closes, and the second solenoid valve of the air inlet and the third solenoid valve of the internal circulation pipeline open, entering the internal circulation period. After the set condensation interval period, the third solenoid valve of the internal circulation pipeline closes, and the second solenoid valve of the air inlet and the first solenoid valve of the condensation pipeline open, allowing the system to re-enter the condensation system. The condensation process and the internal circulation process are carried out alternately until the sample solvent is dried.

[0015] The above-described solution of the present invention has at least the following beneficial effects: The above-described solution of the present invention involves spraying a first volume of solvent into the chamber using an ultrasonic atomizing device, resulting in atomized solvent. The atomized solvent evaporates, causing the solvent vapor within the chamber to reach its saturated vapor pressure. The first volume is greater than a preset value. By controlling the condensation of solvent vapor within the chamber and the solvent evaporation during the internal circulation process through the condensation pipe, the internal circulation pipe, and the air inlet pipe, the drying rate of the sample solvent is controlled. This method allows for low-cost and high-efficiency regulation of the solvent evaporation rate within the chamber, saving time and effectively solving the problem of uncontrollable drying rate, thus achieving a controllable drying rate. Attached Figure Description

[0016] Figure 1 This is a side view of a vacuum drying oven provided in an embodiment of the present invention; Figure 2 This is another side view of the vacuum drying oven provided in an embodiment of the present invention; Figure 3 This is a rear view of the vacuum drying oven provided in an embodiment of the present invention; Figure 4 This is a front view of a vacuum drying oven provided in an embodiment of the present invention; Figure 5 This is a control circuit diagram of a vacuum drying oven provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the upper and lower ventilation inner liner hanging plates of the vacuum drying oven provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the upper and lower ventilation inner liner hanging plates of the vacuum drying oven provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the left and right ventilation inner liner hanging plates of the vacuum drying oven provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the left and right ventilation inner liner hanging plates of the vacuum drying oven provided in an embodiment of the present invention.

[0017] Figure 10 This is a flowchart of the drying rate control method for the vacuum drying oven of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Cabinet; 2. Condensation piping; 3. Internal circulation piping; 4. Air inlet pipe; 5. Air inlet; 6. Exhaust outlet; 7. Storage tank; 71. Atomizing gas inlet; 8. Atomizing tube; 9. Control box; 10. Bracket; 11. First inner liner mounting plate; 12. Second inner liner mounting plate; 13. Third inner liner mounting plate; 100. Door; 101. First temperature sensor; 102. Second temperature sensor; 103. Mixer; 104. Third temperature sensor; 105. Fourth temperature sensor; 106. First accommodating space; 107. Second accommodating space; 108. Third accommodating space; 109. Vent hole; 110. First area without vent hole; 111. Second area without vent hole; 112. Third area without vent hole; 113. Electronic pressure switch; 114. First solenoid valve; 115. Third solenoid valve; 116. Detector; 117. Blower; 118. Second solenoid valve. Detailed Implementation

[0019] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0020] like Figures 1 to 4 As shown, embodiments of the present invention also provide a vacuum drying oven system, comprising: The vacuum drying oven includes a chamber body 1; a condenser pipe 2 connected to the chamber body 1; an internal circulation pipe 3 connected to the chamber body 1 and the condenser pipe 2; an air inlet pipe 4 connected to the internal circulation pipe 3; and an ultrasonic atomizing device connected to the chamber body 1. The ultrasonic atomizing device sprays a first volume of solvent into the chamber 1, and the atomized solvent is obtained by atomization. The evaporation of the atomized solvent causes the solvent vapor in the chamber 1 to reach the saturated vapor pressure. The first volume is greater than a preset value. By controlling the condensation pipe 2, the internal circulation pipe 3 and the air inlet pipe 4, the condensation of the solvent vapor in the chamber 1 and the solvent evaporation during the internal circulation process are controlled, and the drying rate of the sample solvent is controlled.

[0021] This embodiment of the invention controls the drying rate of the sample solvent by controlling the condensation of solvent vapor within the chamber and the solvent evaporation during the internal circulation process through the condensation pipeline, the internal circulation pipeline, and the air inlet pipe. This allows for low-cost and high-efficiency regulation of the solvent evaporation rate within the chamber, saving time and effectively solving the problem of uncontrollable drying rate, thus achieving a controllable drying rate.

[0022] In this embodiment of the invention, the ultrasonic atomizing device may include: an ultrasonic head (not shown in the figure), a storage tank 7, and an atomizing tube 8 connecting the storage tank 7 and the housing; Specifically, the solvent in storage tank 7 is atomized into atomized solvent using an ultrasonic head; High-pressure air is forced into the storage tank 7 through an external air compressor and air pipe, and atomized solvent is forced into the housing 1 through the atomizing pipe 8.

[0023] In an optional embodiment of the present invention, controlling the condensation of solvent vapor inside the vacuum drying oven and the solvent evaporation during the internal circulation process includes: During the condensation process, the condenser pipe 2 and the air inlet pipe 4 connected to the housing 1 are opened. The solvent vapor in the housing 1 enters the condenser pipe 2 for condensation and then enters the air inlet pipe 4 through the internal circulation pipe 3, and then enters the housing 1 again.

[0024] Here, solvent vapor in the chamber 1 enters the condenser pipe 2 through the exhaust port 6, where it is condensed. The condensed gas is then transported to the inlet pipe 4 through the internal circulation pipe 3, and the inlet pipe 4, through the inlet port 5, transports the gas from the internal circulation pipe 3 into the chamber 1. This reduces the solvent vapor content within the chamber.

[0025] During the internal circulation process, the internal circulation pipe 3 and the air inlet pipe 4 connected to the housing 1 are opened. The solvent vapor in the housing 1 enters the air inlet pipe 4 through the internal circulation pipe 3 and then re-enters the housing 1. This achieves the circulation of gas and the evaporation of solvent within the housing.

[0026] Here, the condensation process of the condensation pipeline includes: after the set condensation time period, the first solenoid valve 114 of the condensation pipeline 2 is closed, and the second solenoid valve 118 of the intake pipe 4 and the third solenoid valve 115 of the internal circulation pipeline 3 are opened, entering the internal circulation time period. After the set condensation interval period, the third solenoid valve 115 of the internal circulation pipeline 3 closes, while the second solenoid valve 118 of the air inlet pipe 4 and the first solenoid valve 114 of the condensation pipeline 2 open, allowing condensation to resume. These two processes are performed alternately by the control system until the sample solvent is dried.

[0027] like Figure 5 The diagram shows the circuit control of a vacuum drying oven with controllable drying rate. This circuit can be installed inside the control box 9. In practice, at the beginning stage, the sample to be dried is placed inside the oven body 1, and the oven door 100 is closed.

[0028] Both the solenoid valves of the air inlet 5 and the exhaust port 6 are in the closed state. After pressing the start button, the atomization process begins. The ultrasonic head atomizes the solvent into small droplets, which are then blown into the chamber 1 by compressed air through the atomization tube 8. The atomization time and the atomization interval are controlled by a programmable logic controller (PLC).

[0029] After the atomization stage ends, the solvent vapor in chamber 1 reaches saturated vapor pressure, and the sample solvent will not evaporate. At this time, the condensation cycle begins. The first solenoid valve 114 of the condensation pipe 2 and the second solenoid valve 118 of the air inlet pipe 4 are opened, and the blower 117 starts working at the set speed, and condensation begins.

[0030] After the set condensation time, the first solenoid valve 114 of the condenser pipe 2 closes, and the second solenoid valve 118 of the intake pipe 4 and the third solenoid valve 115 of the internal circulation pipe 3 open, entering the internal circulation.

[0031] After the set condensation interval, the third solenoid valve 115 of the internal circulation pipe 3 closes, and the second solenoid valve 118 of the intake pipe 4 and the first solenoid valve 114 of the condensation pipe 2 open, re-entering the condensation cycle, and so on.

[0032] In the above embodiments of the present invention, the evaporation rate of the solvent is affected by four variables: temperature, vapor pressure, specific surface area, and air velocity flowing over the surface. Vapor pressure refers to the pressure exerted by gas molecules produced by liquid evaporation or solid sublimation on the container walls or other materials. Under specified temperature and pressure, in a sealed container free of air and other substances, a liquid placed at the top evaporates. When the number of liquid molecules evaporating per unit time equals the number of molecules condensing into liquid from the vapor, a phase transition equilibrium is reached. The vapor pressure at this point is called the saturated vapor pressure of the specified liquid at the specified temperature and external pressure.

[0033] The partial pressure of the solvent inside the chamber is controlled by atomization and condensation cycles to regulate the ratio of solvent vapor inside the chamber, thereby controlling the original solvent drying rate inside the chamber.

[0034] like Figure 6 and Figure 7 As shown, in an optional embodiment of the present invention, the air inlet 5 is located at a first position on the back of the housing 1, and the exhaust port 6 is located at a second position on the back of the housing 1. The first position and the second position are arranged vertically.

[0035] The housing 1 is provided with a first inner liner hanging plate 11. The first inner liner hanging plate 11 and the inner wall of the back where the air inlet 5 and the exhaust port 6 are located form a first accommodating space 106. The air inlet 5, the exhaust port 6 and the atomizing gas inlet 71 of the ultrasonic atomizing device are located in the first accommodating space. The first inner liner hanging plate 11 has evenly distributed vent holes 109.

[0036] In this embodiment, the air inlet 5 and the exhaust outlet 6 are located on the upper and lower sides of the back of the box 1, respectively. A first inner liner hanging plate 11 is provided on the side wall where the air inlet 5 and the exhaust outlet 6 are located inside the box. Small ventilation holes 109 are evenly opened on the first inner liner hanging plate 11. There is a second area without ventilation holes 111 at the location of the air inlet 5, so that the gas entering the box 1 will not directly enter the box, but will enter the box through the ventilation holes 109 on the first inner liner hanging plate 11, making the gas in the box 1 more uniform. Similarly, a first ventless area 110 is provided at the location of the exhaust port 6, so that the gas discharged through the vent 109 on the first inner liner hanging plate 11 enters the exhaust port, ensuring that the gas inside the box is fully mixed gas.

[0037] Furthermore, a first temperature sensor 101 is provided near the air inlet 5, and a second temperature sensor 102 is provided at the exhaust outlet 6, so as to monitor the temperature of the gas in the air inlet 5 and the temperature of the gas in the exhaust outlet 6.

[0038] like Figure 8 and Figure 9 As shown, in an optional embodiment of the present invention, the air inlet 5 is located on the first side of the housing 1, the exhaust port 6 is located on the second side of the housing 1, and the air inlet 5 and the exhaust port 6 are located on the same horizontal line.

[0039] Here, the box 1 is provided with a second inner liner hanging plate 12 and a third inner liner hanging plate 13; The third inner liner mounting plate 13 and the inner wall of the first side where the air inlet 5 is located form a second accommodating space 107; the air inlet 5 is located in the second accommodating space 107; The second inner liner mounting plate 12 and the inner wall of the second side where the exhaust port 6 is located form a third receiving space 108; the exhaust port 6 is located in the third receiving space 108; The second inner liner hanging plate 12 and the third inner liner hanging plate 13 have evenly distributed ventilation holes 109.

[0040] In this embodiment, the air inlet 5 and the exhaust outlet 6 are located on the left and right sides of the chamber 1, respectively. Hanging plates are provided on the left and right sides inside the chamber 1. Small ventilation holes 109 are evenly opened on the second inner liner hanging plate 12 and the third inner liner hanging plate 13. The center of the second inner liner hanging plate 12 and the third inner liner hanging plate 13 has a third non-ventilated area 112 to prevent the airflow from concentrating in the middle, resulting in a faster flow rate of the sample solvent surface. The airflow after passing through the second inner liner hanging plate 12 and the third inner liner hanging plate 13 is more evenly distributed inside the chamber 1 of the oven. Furthermore, a third temperature sensor 104 is provided near the air inlet 5, and a fourth temperature sensor 105 is provided at the exhaust outlet 6, so as to monitor the temperature of the gas at the air inlet 5 and the temperature of the gas at the exhaust outlet 6.

[0041] Preferably, the diameter of the vent hole is 2-15mm. The third ventless range 112 can be a ventless range formed by sealing the small holes within the circle with the center of the second inner liner hanging plate 12 and the third inner liner hanging plate 13 as the center and the diameter of the air inlet as 1-5 times the diameter of the air inlet with tape.

[0042] In an optional embodiment of the present invention, heating wires may be provided around the enclosure 1 to provide heating for the enclosure 1. At least one of the following is provided on the outer shell of the enclosure 1: a power switch, a power indicator light, a pressure gauge, and a temperature setting panel. A start button and an emergency stop button are provided on the outer side of the enclosure 1.

[0043] The exhaust port 6 connected to the housing 1 is controlled by a solenoid valve to enter either the condenser pipe 2 or the internal circulation pipe 3. A solvent vapor content detector is also installed on the exhaust pipe to monitor the solvent vapor content inside the housing.

[0044] A stirrer 103 can also be installed inside the housing 1 to stir the atomized solvent, so that the atomized solvent enters the housing 1 more evenly.

[0045] The condenser pipe 2 includes two condenser pipes, one inside and one outside, with low-temperature condensate circulating between the two condenser pipes. The gas discharged from the exhaust port 6 enters the inner condenser pipe and condenses and liquefies.

[0046] The air intake pipe 4 of the housing 1 is controlled by a solenoid valve to open and close. The air intake pipe 4 is directly connected to the internal circulation pipe 3, and a blower 117 is installed in the middle. The blower 117 provides gas circulation power to the air intake pipe 4. The gas re-enters the housing 1 through the internal circulation pipe 3 and the blower 117.

[0047] The back of the housing 1 has an atomizing gas inlet 71, which is connected to an ultrasonic atomizing device. The ultrasonic atomizing device includes an ultrasonic head, a storage tank 7, and an atomizing tube 8 connecting the storage tank 7 and the housing 1.

[0048] The storage tank 7 contains liquid solvent. The ultrasonic head is controlled by a programmable logic controller. When working, the ultrasonic head emits ultrasonic waves to atomize the liquid solvent into small droplets.

[0049] The air compressor pressurizes high-pressure air into the storage tank 7 through the air pipe, and the atomized droplets are pressed into the box 1 from the atomizing pipe 8, so as to achieve the effect of spraying atomized solvent droplets from the atomizing gas inlet 71 in the box 1.

[0050] like Figure 5 As shown, the programmable logic controller (PLC) is a control system that can control the opening and closing of the solenoid valves in the condenser pipe 2, the internal circulation pipe 3, and the intake pipe 4. Configurable parameters include atomization time, atomization interval time, condensation time, condensation interval time, and blower speed. It can also control the entry and exit of each process.

[0051] A vacuum drying oven with controllable drying rate uses an ultrasonic atomizing device to spray excess solvent droplets into a sealed chamber 1. At the heating temperature, the atomized droplets evaporate, and the solvent vapor inside chamber 1 reaches its saturation vapor pressure, at which point the original solvent ceases to evaporate. The rate of solvent vapor reduction within the chamber is then controlled through a condensation cycle, allowing the original solvent inside chamber 1 to evaporate in a controlled manner through the condensation and internal circulation processes. This solves the problem of uncontrollable drying rate and achieves a controllable drying rate.

[0052] like Figure 10 As shown, embodiments of the present invention also propose a method for controlling the drying rate of a vacuum drying oven, comprising: Step 101: Place the sample solvent to be dried into the vacuum drying oven. Step 102: A first volume of atomized solvent is sprayed into the chamber using an ultrasonic atomizing device. The atomized solvent evaporates, causing the solvent vapor in the chamber to reach saturated vapor pressure. The first volume is greater than a preset value. Step 103: The drying rate of the sample solvent is controlled by controlling the condensation of solvent vapor inside the vacuum drying oven and the evaporation of solvent during the internal circulation process.

[0053] In this embodiment, the drying rate of the sample solvent is controlled by controlling the condensation of solvent vapor within the chamber and the solvent evaporation during the internal circulation process through the condensation pipeline, the internal circulation pipeline, and the air inlet pipe. This allows for low-cost and high-efficiency regulation of the solvent evaporation rate within the chamber, while also saving time and effectively solving the problem of uncontrollable drying rate, thus achieving a controllable drying rate.

[0054] In an optional embodiment of the present invention, the ultrasonic atomizing device includes: an ultrasonic head, a storage tank, and an atomizing tube connecting the storage tank and the housing; the ultrasonic atomizing device sprays a first volume of atomized solvent droplets into the housing, comprising: The solvent in the storage tank is atomized into atomized solvent using an ultrasonic head; High-pressure air is forced into the storage tank through an external air compressor and air pipes, and atomized solvent is forced into the housing through the atomizing pipe.

[0055] Optionally, controlling the condensation of solvent vapor inside the vacuum drying oven and the solvent evaporation during the internal circulation process includes: The condenser pipe and the internal circulation pipe are alternately connected by controlling the opening of the condenser pipe and the air inlet pipe connected to the housing through the solenoid valve. During the condensation process, the condensation pipe and the air inlet pipe connected to the box are opened. The solvent vapor inside the box enters the condensation pipe for condensation treatment and then enters the air inlet pipe through the internal circulation pipe.

[0056] During the internal circulation process, the internal circulation pipeline and air inlet pipe connected to the chamber are opened, and the solvent vapor inside the chamber circulates between the chamber and the internal circulation pipeline. The above two processes are alternately performed by the control system until the sample solvent is dried.

[0057] Optionally, the condensation treatment of the condensation pipeline includes: After the set condensation period, the first solenoid valve of the condensation pipeline closes, and the second solenoid valve of the air inlet and the third solenoid valve of the internal circulation pipeline open, entering the internal circulation period. After the set condensation interval, the third solenoid valve in the internal circulation pipeline closes, while the second solenoid valve at the air inlet and the first solenoid valve in the condensation pipeline open, allowing condensation to resume. These two processes are performed alternately by the control system until the sample solvent is dried.

[0058] In the above embodiments of the present invention, an excess of small solvent droplets is sprayed into a sealed chamber 1 using an ultrasonic atomizing device. The atomized droplets evaporate at a heating temperature, and the solvent vapor inside the chamber 1 reaches its saturated vapor pressure, at which point the original solvent ceases to evaporate. The rate of solvent vapor reduction within the chamber is then controlled by a condensation cycle, allowing the original solvent to evaporate controllably through the condensation and internal circulation processes. This solves the problem of uncontrollable drying rate and achieves a controllable drying rate.

[0059] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for controlling the drying rate of a vacuum drying oven, characterized in that, The method is applied to a vacuum drying oven and includes: The vacuum drying oven has a chamber (1) and heating wires are provided around the chamber (1); Condensation pipe (2) connected to the housing (1); An internal circulation pipe (3) is connected to the housing (1) and the condenser pipe (2); The air intake pipe (4) is connected to the internal circulation pipe (3); An ultrasonic atomizing device connected to the housing (1); The condenser pipeline (2) includes two condenser pipes, with a condensate circulation system between the two condenser pipes; The air intake pipe (4) is connected to the internal circulation pipe (3), and a blower (117) is installed in the middle. The exhaust port (6) connected to the housing (1) is controlled by a solenoid valve to enter the condenser pipe (2) or the internal circulation pipe (3), and a solvent vapor content detector is also provided on the exhaust pipe; The ultrasonic atomizing device includes an ultrasonic head, a storage tank (7) and an atomizing tube (8) connecting the storage tank (7) and the housing (1). The ultrasonic head is controlled by a programmable logic controller. The programmable logic controller controls the opening and closing of the solenoid valves of the condenser pipe (2), the internal circulation pipe (3) and the air inlet pipe (4), and sets the atomization time, atomization interval time, condensation time, condensation interval time and blower speed parameters. Place the sample solvent to be dried into the chamber (1) of the vacuum drying oven; The first volume of solvent is sprayed into the housing (1) by an ultrasonic atomizing device to obtain atomized solvent. The atomized solvent evaporates so that the solvent vapor in the housing (1) reaches the saturated vapor pressure. The first volume is greater than a preset value. The solvent in the storage tank (7) is atomized into atomized solvent by an ultrasonic head. High-pressure air is pressed into the storage tank (7) by an external air compressor and air pipe. The atomized solvent is pressed into the housing (1) through the atomizing pipe. The drying rate of the sample solvent is controlled by controlling the condensation of solvent vapor inside the chamber (1) of the vacuum drying oven and the evaporation of solvent during the internal circulation process. The control process is as follows: the condenser pipe (2) and the internal circulation pipe (3) connected to the housing (1) are opened by controlling the solenoid valve to alternately connect the condenser pipe (2) and the internal circulation pipe (3). During the condensation process, the gas in the box (1) enters the condensation pipe (2) through the exhaust port (6), and the condensation pipe (2) condenses the gas. The condensed gas is then transported to the inlet pipe (4) through the internal circulation pipe (3). The inlet pipe (4) transports the gas from the internal circulation pipe (3) to the box (1) through the inlet port (5). During the internal circulation process, the solvent vapor in the box (1) enters the internal circulation pipe (3) and re-enters the box (1) through the internal circulation pipe (3) and the inlet pipe (4). The condensation process and the internal circulation process alternate.

2. The drying rate control method for a vacuum drying oven according to claim 1, characterized in that, The air inlet (5) is located at a first position on the back of the housing (1), and the exhaust port (6) is located at a second position on the back of the housing (1). The first position and the second position are arranged vertically.

3. The drying rate control method for a vacuum drying oven according to claim 2, characterized in that, The box (1) is provided with a first inner liner hanging plate (11). The first inner liner hanging plate (11) and the inner wall of the back where the air inlet (5) and the exhaust port (6) are located form a first accommodating space (106). The air inlet (5), the exhaust port (6) and the atomizing gas inlet (71) of the ultrasonic atomizing device are located in the first accommodating space. The first inner liner hanging plate (11) has evenly distributed vent holes (109). The first inner liner hanging plate (11) has a second non-ventilated area (111) at the location of the air inlet (5) and a first non-ventilated area (110) at the location of the exhaust port (6).

4. The drying rate control method for a vacuum drying oven according to claim 1, characterized in that, The air inlet (5) is located on the first side of the housing (1), and the exhaust port (6) is located on the second side of the housing (1). The first side and the second side are two opposite sides of the housing, and the air inlet (5) and the exhaust port (6) are located on the same horizontal line.

5. The drying rate control method for a vacuum drying oven according to claim 4, characterized in that, The box (1) is provided with a second inner liner hanging plate (12) and a third inner liner hanging plate (13); The second inner liner mounting plate (12) and the inner wall of the first side where the air inlet (5) is located form a second accommodating space (108); the air inlet (5) is located in the second accommodating space (108); The third inner liner mounting plate (13) and the inner wall of the second side where the exhaust port (6) is located form a third receiving space (107); the exhaust port (6) is located in the third receiving space (107); The second inner liner hanging plate (12) and the third inner liner hanging plate (13) have evenly distributed vent holes (109); the center of the second inner liner hanging plate (12) and the third inner liner hanging plate (13) has a third ventless area (112), the third ventless area (112) is a circle with the center of the second inner liner hanging plate (12) and the third inner liner hanging plate (13) as the center, and the diameter is 1 to 5 times the diameter of the air inlet (5), and the small holes inside the circle are sealed with tape to form a ventless area.

6. The drying rate control method for a vacuum drying oven according to claim 1, characterized in that, The condensation process in the condensation pipeline includes: After the set condensation period, the first solenoid valve of the condensation pipeline closes, and the second solenoid valve of the air inlet and the third solenoid valve of the internal circulation pipeline open, entering the internal circulation period. After the set condensation interval period, the third solenoid valve of the internal circulation pipeline closes, and the second solenoid valve of the air inlet and the first solenoid valve of the condensation pipeline open, allowing the system to re-enter the condensation system. The condensation process and the internal circulation process are carried out alternately until the sample solvent is dried.

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