Condensation separation device with adjustable vacuum degree

Abstract

The utility model relates to the technical field of laboratory vacuum, and particularly provides a vacuum-degree-adjustable condensation separation device aiming at the problems that a vacuum pump is damaged due to the fact that the vacuum degree is not adjustable and gas phase condensation is incomplete in the negative pressure evaporation process, and the vacuum-degree-adjustable condensation separation device comprises an evaporation device, a buffer device and the vacuum pump which are sequentially connected. The buffering device comprises a buffering tank, an inner coil pipe type condensation pipe, an outer clamping sleeve, an adjusting valve, a double-liquid-discharging-valve assembly and a vacuum meter. An inlet of the buffer device is connected with the evaporation system through a pipeline, an outlet of the buffer device is connected with the vacuum pump through a pipeline, and an inlet regulating valve and an outlet regulating valve are installed on the inlet pipeline and the outlet pipeline. According to the utility model, condensation and separation of gas-phase substances are realized through the integrated buffer device; through linkage of the vacuum meter and the outlet adjusting valve, accurate adjustment of the vacuum degree of the laboratory vacuum system and effective protection of the vacuum pump are achieved, the experiment efficiency and the equipment safety are remarkably improved, and the practical value and the popularization significance are high.

Description

Technical Field

[0001] This utility model relates to the field of laboratory vacuum technology, and in particular to the problem of vacuum pump damage caused by incomplete vapor phase condensation during negative pressure evaporation, providing a condensation separation device with adjustable vacuum. Background Technology

[0002] In laboratory negative pressure evaporation operations, existing vacuum systems typically connect the vacuum pump directly to the evaporation device to be depressurized. This direct connection method has several problems: First, the vacuum level provided by the vacuum pump is fixed and cannot be adjusted according to experimental needs, especially in experimental scenarios where only a slight negative pressure is required; second, because the vacuum pump is directly connected to the evaporation device, if the uncondensed gaseous substances generated during the evaporation process are not completely condensed, they will be sucked into the vacuum pump, which can easily damage the vacuum pump and affect the service life of the equipment.

[0003] Chinese Patent Publication No. CN214662894U discloses a vacuum condensing buffer tank, comprising a buffer tank body. Inside the buffer tank body are a liquid storage chamber and a heating chamber, with the heating chamber located directly below the liquid storage chamber. An electric heating element is installed inside the heating chamber. A vacuum pump is installed at the top of the buffer tank body, with an exhaust port on one end and the other end connected to the interior of the buffer tank body via a suction pipe equipped with a suction valve. A condenser is installed inside the buffer tank body, and a condenser tube is installed inside the condenser. However, the vacuum pump provides a fixed vacuum level during operation, which cannot be adjusted according to experimental requirements.

[0004] Therefore, this utility model discloses a condensation separation device with adjustable vacuum. Utility Model Content

[0005] The problems this invention aims to solve are: first, the vacuum level provided by the vacuum pump is fixed during operation and cannot be adjusted according to experimental requirements, especially in experimental scenarios where only a slight negative pressure is required; second, since the vacuum pump is directly connected to the evaporation device, if the uncondensed gaseous substances generated during the evaporation process are not completely condensed, they will be sucked into the vacuum pump, which can easily damage the vacuum pump and affect the service life of the equipment.

[0006] The purpose of this invention is to overcome the defects in the existing technology and provide a condensation and separation device with adjustable vacuum, including an evaporation device, a buffer device, and a vacuum pump, which are connected in sequence. The evaporation device is used for negative pressure evaporation or drying of materials and can be a rotary evaporator or a vacuum evaporator, which are conventional laboratory equipment. The vacuum pump serves as a pumping power source and can be a rotary vane vacuum pump, a water ring vacuum pump, or a diaphragm vacuum pump, or other commonly used laboratory vacuum pumps. The buffer device realizes the condensation and separation of gaseous substances.

[0007] As a further technical solution, the buffer device includes a buffer tank, an inner coil condenser, an outer jacket, a regulating valve, a double drain valve assembly, and a vacuum gauge.

[0008] As a further technical solution, the regulating valve is a manual regulating valve, specifically a ball valve or a shut-off valve, with an opening adjustment range of 0%-100%, which controls the gas flow between the evaporator and the buffer device, and between the buffer device and the vacuum pump, respectively; the vacuum degree is precisely adjusted by controlling different opening degrees of the regulating valve; and the vacuum gauge monitors the vacuum degree in the buffer device in real time.

[0009] As a further technical solution, the structure of the internal coil condenser is a serpentine copper or stainless steel tube wound around the inner wall of the buffer tank or running through the middle of the buffer tank, or a combination of both, with a tube diameter of 2-5 mm; the tube is filled with a low-temperature coolant with a temperature range of -20℃ to 0℃, specifically an aqueous solution of ethylene glycol.

[0010] As a further technical solution, a dual drain valve assembly is used to discharge condensate at the bottom of the buffer device. The structure of the dual drain valve assembly includes a pilot valve, a main drain valve, and a local heating device. The pilot valve is a ball valve or needle valve with a diameter of 8-12 mm, used to initially release condensate. The collected condensate enters the cavity between the two valves. Before draining, the pilot valve is closed to isolate the vacuum, and the condensate is drained through the main drain valve. The volume of the cavity between the two valves is ≤10% of the volume of the buffer device to avoid pressure fluctuations during the draining process of the buffer tank. The main drain valve is a ball valve or a stop valve with a diameter of 8-12 mm to achieve controllable discharge. The local heating device is an electric heating tape or a constant temperature jacket with a temperature controllable range of 25℃-60℃ to prevent low-temperature condensate from freezing and clogging the valve.

[0011] As a further technical solution, the outer jacket is a jacket that wraps around the outer wall of the buffer tank, with a thickness of 10-20mm; the medium inside the jacket is a refrigerant with a temperature of -20℃ to 0℃, specifically an aqueous solution of ethylene glycol.

[0012] As a further technical solution, the vacuum gauge is a digital display vacuum pressure gauge or a precision pointer vacuum gauge, with a range of -100 kPa to 0 kPa and an accuracy class of 0.1.

[0013] As a further technical solution, the pipe between the evaporator and the buffer device, or the pipe between the buffer device and the vacuum pump, is set as n small pipes, the sum of the cross-sectional areas of the n small pipes is equal to the cross-sectional area of ​​the pipe; each small pipe is equipped with a valve, and the vacuum degree can be adjusted by opening and closing the valves on the small pipes.

[0014] As a further technical solution, the buffer tank is made of pressure-resistant metal material, specifically 304 stainless steel or 316L stainless steel. The stainless steel inner wall of the buffer tank is pickled and passivated. The volume of the buffer tank is 5 L to 20 L, and it can be designed in different sizes, specifically 5 L, 10 L, 15 L and 20 L, to meet the needs of different scale experiments. The inner wall of the buffer tank is equipped with baffles.

[0015] As a further technical solution, a through-viewing mirror is installed in the pipeline between the pilot valve and the main drain valve.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] 1) Precise vacuum adjustment: By setting regulating valves at the inlet and outlet of the buffer device, the pumping volume can be precisely adjusted according to experimental requirements, achieving vacuum adjustment between 0 and -100 kPa. This meets the diverse vacuum requirements of different experiments, improves the accuracy and repeatability of experiments, and solves the problem that existing direct-connected vacuum pumps cannot accurately control the vacuum level. This capability greatly improves the accuracy and repeatability of experiments.

[0018] 2) Protecting the vacuum pump: The buffer device serves to buffer and separate the gas phase. The gas phase enters the buffer device before entering the vacuum pump, allowing uncondensed gas more time and space to condense. Simultaneously, the drain valve at the bottom promptly discharges the condensate, effectively preventing uncondensed gas and liquid from entering the vacuum pump, significantly extending its service life and reducing equipment maintenance costs.

[0019] 3) Real-time monitoring: The vacuum gauge installed on the upper part of the buffer device can display the vacuum level in real time. Experimenters can intuitively understand the vacuum status of the system, which makes it easy to adjust the vacuum level in a timely manner and ensure that the experiment is carried out under suitable vacuum conditions. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a vacuum-adjustable condensation separation device and an inner-wall coil condenser according to the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of a vacuum-adjustable condensation separation device and a through-type coil condenser according to the present invention.

[0022] Figure 3 This is a schematic diagram of the pipe structure connecting the evaporation device and the buffer device of this utility model.

[0023] Explanation of reference numerals in the attached figures:

[0024] A, Evaporation unit; B, Vacuum pump; 1, Regulating valve; 2, Double drain valve assembly; 3, Buffer device; 3a, Buffer tank; 3b, Internal coil condenser; 3c, External jacket; 4, Vacuum gauge; 5, Regulating valve; 6a, Pipeline; 6b, Small pipe; 6c, Valve; 7, Baffle. Detailed Implementation

[0025] The technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0027] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and connections within two components or interactions between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] This invention provides a condensation and separation device with adjustable vacuum. The control system includes an evaporation device A, a buffer device 3, and a vacuum pump B, which are connected in sequence. The evaporation device A is used for negative pressure evaporation or drying of materials and can be a rotary evaporator or a vacuum evaporator, which are conventional laboratory equipment. The vacuum pump B serves as a pumping power source and can be a rotary vane vacuum pump, a water ring vacuum pump, or a diaphragm vacuum pump, which are commonly used laboratory vacuum pumps. The buffer device 3 realizes gradient condensation and separation with gaseous substances.

[0029] The buffer device 3 includes a buffer tank 3a, an inner coil condenser 3b, an outer jacket 3c, regulating valves 1 and 5, a double drain valve assembly 2, a vacuum gauge 4, and a baffle 7.

[0030] Regulating valves 1 and 5 are manual regulating valves, specifically ball valves or shut-off valves, with an opening adjustment range of 0%-100%, respectively controlling the gas flow between evaporator A and buffer device 3, and between buffer device 3 and vacuum pump B; the vacuum level is precisely adjusted by controlling the opening of regulating valve 5; vacuum gauge 4 monitors the vacuum level in buffer device 3 in real time.

[0031] The internal coil condenser 3b is a serpentine copper or stainless steel tube wound around the inner wall of the buffer tank 3a or penetrating the middle of the buffer tank 3a, or a combination of both. The tube diameter is 2-5 mm, and the tube is filled with a low-temperature coolant with a temperature range of -20℃ to 0℃, specifically an aqueous solution of ethylene glycol.

[0032] The dual drain valve assembly 2 is used to discharge condensate from the bottom of the buffer device 3. The structure of the dual drain valve assembly 2 includes a pilot valve 2a, a main drain valve 2c, and a local heating device 2b. The pilot valve 2a is a ball valve or needle valve with a diameter of 8-12 mm, used for initial release of condensate. The collected condensate enters the cavity between the two valves. Before drainage, the pilot valve is closed to isolate a vacuum, and drainage is then carried out through the main drain valve 2c. The volume of the cavity between the two valves is ≤10% of the volume of the buffer device 3. The main drain valve 2c is a ball valve or gate valve with a diameter of 8-12 mm, enabling controlled drainage. The local heating device 2b is an external electric heating tape or thermostatic jacket, with a controllable temperature range of 25℃-60℃, preventing low-temperature condensate from freezing and clogging the valves. A through-viewing mirror is installed on the pipe between the pilot valve 2a and the main drain valve 2c.

[0033] The outer jacket 3c is a jacket that wraps around the outer wall of the buffer tank 3a, with a thickness of 10-20 mm; the medium inside the jacket is a refrigerant with a temperature of -20℃ to 0℃, specifically an aqueous solution of ethylene glycol.

[0034] Vacuum gauge 4 is a digital vacuum pressure gauge or a precision pointer vacuum gauge with a range of -100 kPa to 0 kPa and an accuracy class of 0.1.

[0035] The pipe 6a between the evaporator A and the buffer device 3, or the pipe 6a between the buffer device 3 and the vacuum pump B, is set as n small pipes 6b, and the sum of the cross-sectional areas of the n small pipes is equal to the cross-sectional area of ​​the pipe 6a; each small pipe is equipped with a valve 6c, and the vacuum degree can be adjusted by opening and closing the valves 6c on the small pipes.

[0036] The buffer tank 3a is made of pressure-resistant metal material, specifically 304 stainless steel or 316L stainless steel. The stainless steel inside the buffer tank undergoes pickling and passivation treatment. The volume of the buffer tank 3a ranges from 5 L to 20 L and can be designed in different sizes, specifically 5 L, 10 L, 15 L, and 20 L, to meet the needs of experiments of different scales. The inner wall of the buffer tank 3a is equipped with baffles.

[0037] When using the vacuum system of this invention to conduct a negative pressure evaporation experiment, firstly, according to the required vacuum level (e.g., -70 kPa), manually adjust the opening of the regulating valve 5 on the pipeline between the buffer device 3 and the vacuum pump B, and the regulating valve 1 on the pipeline between the buffer device 3 and the evaporation device A, to control the amount of air pumped by the vacuum pump B to the evaporation device A. By adjusting the valve opening, ensure that the system can quickly and stably reach and maintain the set vacuum level.

[0038] Throughout the operation, vacuum gauge 4 continuously monitors the vacuum level inside buffer device 3. Experimenters can observe the digital display reading of vacuum gauge 4 to understand the current vacuum status of the system and adapt to the vacuum requirements under specific experimental conditions. The error range can be controlled within ±0.5 kPa.

[0039] During the evaporation process, some of the uncondensed gaseous substances escaping from evaporator A first enter buffer device 3. These gaseous substances are gradually condensed into liquid by the action of the inner coil condenser 3b and the outer jacket 3c. The condensed liquid accumulates at the bottom of buffer tank 3a and can be safely discharged by periodically opening the double drain valve assembly 2. Specifically, before discharging the condensate, a local heating device 2c is activated to preheat the condensate to a suitable temperature (e.g., 40°C) to prevent freezing or blockage due to excessively low temperatures.

[0040] The buffer device 3 not only serves as a condensation and separation mechanism but also effectively mitigates the pressure shock caused by gas directly entering the vacuum pump B, significantly reducing the risk of damage to the vacuum pump B due to instantaneous high pressure or the intake of uncondensed gas. Furthermore, this buffer design allows the system to maintain stable operation when faced with instantaneous flow rate changes, improving the overall system reliability and service life.

[0041] Example 1: Condensation Separation under Micro-Negative Pressure Environment

[0042] Application scenario: This embodiment is for laboratory operations that require a slightly negative pressure environment (such as -5 kPa to -10 kPa), such as drying easily oxidizable materials or precision chemical synthesis, requiring a vacuum fluctuation range of ≤ ±0.1 kPa, and needing to avoid the interference of pressure changes on the experimental system.

[0043] Structural configuration:

[0044] Buffer device 3: Select a 5 L buffer tank 3a; the inner coil condenser 3b is a through stainless steel pipe with a diameter of 5 mm, which carries -10℃ refrigerant; the outer jacket 3c has a thickness of 20 mm and carries -10℃ refrigerant.

[0045] Vacuum pump B: Water ring vacuum pump with an ultimate vacuum of -95 kPa, but its pumping capacity is limited by regulating valve 5 to keep the system stable between -5 kPa and -10 kPa.

[0046] Piping system: Four small pipes 6b (total cross-sectional area equal to pipe 6a) are installed between buffer device 3 and vacuum pump B. Each pipe is equipped with a valve 6c. The flow rate can be adjusted in different levels by opening and closing the pipes (e.g., single pipe corresponds to -5 kPa, double pipe corresponds to -10 kPa).

[0047] Working principle:

[0048] Vacuum establishment: Close all valves 6c of small pipes 6b, slightly open the regulating valve to 5% opening, and start vacuum pump B. Monitor in real time using vacuum gauge 4, gradually increase the regulating valve opening to 5% to stabilize the system vacuum at -10 kPa (target value), and open valves 6c of the two small pipes 6b.

[0049] Gas phase treatment: Trace amounts of gaseous substances (such as water vapor) escaping from evaporator A enter buffer tank 3a, and are partially condensed by inner coil condenser 3b (-10℃ ethylene glycol). Uncondensed gas is further cooled by outer jacket 3c (-10℃ ethylene glycol).

[0050] Vacuum maintenance: The vacuum level can be continuously adjusted from -5 kPa to -10 kPa by adjusting the opening of valve 5, with a fluctuation range of ≤ ±0.1 kPa. If a higher vacuum level is required, valve 6c of the three small pipes 6b can be opened to increase the pumping capacity to -15 kPa.

[0051] Condensate drainage: Before draining, close the pilot valve 2a, preheat the local heating device 2b to 30°C to prevent the condensate from freezing, and then open the main drain valve 2c to drain the liquid.

[0052] Example 2: Small-scale production experiment (20 L buffer tank)

[0053] Experimental background: In kilogram-scale synthesis, a large amount of solvent evaporation needs to be handled, requiring high flow rates and stability.

[0054] Buffer device 3: A 20 L buffer tank 3a is selected, with baffles installed on the inner wall to extend the airflow path; the inner coil condenser 3b is an inner wall stainless steel tube with a diameter of 5 mm, purified with -20℃ refrigerant; the outer jacket 3c is 20 mm thick, purified with -20℃ refrigerant. The tiered design and multi-pipe adjustment of the buffer tank 3a can adapt to the needs of experiments of different scales.

[0055] Sub-piping design: The pipe 6a between evaporator A and buffer tank is divided into 4 smaller pipes 6b, each equipped with an independent valve 6c. By opening 2-4 smaller pipes, the total flow rate can be adjusted to meet the needs of large-scale evaporation.

[0056] Vacuum pump selection: Rotary vane vacuum pump B is selected because its high flow rate characteristics are suitable for high evaporation rates; vacuum gauge 4 shows that the vacuum level is stable at the required level, which meets production requirements.

[0057] Operating procedure: Set the opening of regulating valves 1 and 5 to 70%, and in conjunction with the opening of multiple pipelines, achieve a gas processing capacity of 100 L per minute.

[0058] The condensate is continuously discharged through the main drain valve 2c of the dual drain valve assembly 2, and the local heating device 2b maintains the temperature at 40°C.

[0059] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. The above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A condensation and separation device with adjustable vacuum level, characterized in that, The condensation separation device includes an evaporation device (A), a buffer device (3), and a vacuum pump (B), which are connected in sequence. The evaporation device (A) is used for negative pressure evaporation or drying of materials and can be a rotary evaporator or a vacuum evaporator, which are conventional laboratory equipment. The vacuum pump (B) serves as a pumping power source and can be a rotary vane vacuum pump, a water ring vacuum pump, or a diaphragm vacuum pump, which are commonly used laboratory vacuum pumps. The buffer device (3) realizes gradient condensation separation of gaseous substances.

2. The vacuum-adjustable condensation separation device according to claim 1, characterized in that, The buffer device (3) includes a buffer tank (3a), an inner coil condenser (3b), an outer jacket (3c), regulating valves (1, 5), a double drain valve assembly (2), and a vacuum gauge (4).

3. The vacuum-adjustable condensation separation device according to claim 2, characterized in that, The regulating valves (1, 5) are manual regulating valves, specifically ball valves or shut-off valves, with an opening adjustment range of 0%-100%, respectively controlling the gas flow between the evaporator (A) and the buffer device (3), and between the buffer device (3) and the vacuum pump (B); the vacuum degree is precisely adjusted by controlling the opening of the regulating valve (5); the vacuum gauge (4) monitors the vacuum degree in the buffer device (3) in real time.

4. The vacuum-adjustable condensation separation device according to claim 2, characterized in that, The structure of the inner coil condenser (3b) is a serpentine copper or stainless steel tube wound around the inner wall of the buffer tank (3a) or penetrating the middle of the buffer tank (3a) or a combination of both, with a tube diameter of 2-5 mm; the tube is filled with a low-temperature coolant with a temperature range of -20℃ to 0℃, specifically an ethylene glycol aqueous solution.

5. The vacuum-adjustable condensation separation device according to claim 4, characterized in that, The dual drain valve assembly (2) is used to discharge the condensate at the bottom of the buffer device (3). The structure of the dual drain valve assembly (2) includes a pilot valve (2a), a main drain valve (2c), and a local heating device (2b). The pilot valve (2a) is a ball valve or needle valve with a diameter of 8-12 mm. It is used to initially release the condensate. The collected condensate enters the cavity between the two valves. Before draining, the pilot valve (2a) is closed to isolate the vacuum. The condensate is drained through the main drain valve (2c). The volume of the cavity between the two valves is ≤ 10% of the volume of the buffer device (3) to avoid pressure fluctuations during the draining process of the buffer tank. The main drain valve (2c) is a ball valve or shut-off valve with a diameter of 8-12 mm to achieve controllable discharge. The local heating device (2b) is an electric heating tape or constant temperature jacket outside the cavity. The temperature is controllable within the range of 25℃-60℃ to prevent the low-temperature condensate from freezing and clogging the valve.

6. The vacuum-adjustable condensation separation device according to claim 2, characterized in that, The outer jacket (3c) is a jacket that wraps around the outer wall of the buffer tank (3a) and has a thickness of 10-20 mm; the medium inside the jacket is a refrigerant with a temperature of -20℃ to 0℃, specifically an aqueous solution of ethylene glycol.

7. A vacuum-adjustable condensation separation device according to claim 2, characterized in that, The vacuum gauge (4) is a digital vacuum pressure gauge or a precision pointer vacuum gauge with a range of -100 kPa to 0 kPa and an accuracy class of 0.

1.

8. The vacuum-adjustable condensation separation device according to claim 1, characterized in that, The pipe (6a) between the evaporator (A) and the buffer device (3) or the pipe (6a) between the buffer device (3) and the vacuum pump (B) is set as n small pipes (6b), and the sum of the cross-sectional areas of the n small pipes is equal to the cross-sectional area of ​​the pipe (6a); each of the small pipes is equipped with a valve (6c), and the vacuum degree can be adjusted by opening and closing the valves (6c) on the small pipes.

9. A vacuum-adjustable condensation separation device according to claim 2, characterized in that, The buffer tank (3a) is made of pressure-resistant metal material, specifically 304 stainless steel or 316L stainless steel. The stainless steel inner wall of the buffer tank is pickled and passivated. The volume of the buffer tank (3a) is 5 L to 20 L, and it can be designed in different sizes, specifically 5 L, 10 L, 15 L and 20 L, to meet the needs of different scale experiments. The inner wall of the buffer tank (3a) is provided with baffles (7).

10. A vacuum-adjustable condensation separation device according to claim 5, characterized in that, A through-view mirror is provided in the pipeline between the pilot valve (2a) and the main drain valve (2c).

Images