Vacuum pump of freeze dryer and exhaust method thereof

Abstract

The freeze dryer vacuum pump comprises an end cover body, a pump body assembly and a motor assembly which are in transmission connection are arranged at the two ends of the end cover body respectively, an oil tank shell in sealing connection with the end cover body is further arranged on the end cover body, and the oil tank shell communicates with an inner cavity of the pump body assembly; an exhaust assembly connected with the oil tank shell in a sealed mode is arranged at the top of the oil tank shell and comprises a valve block capable of moving up and down. The end cover body is provided with a gas ballast assembly used for controlling the communication state of a flow channel in the end cover body and the pump body assembly, and the gas ballast assembly comprises a rotary knob body capable of rotating relative to the end cover body. The gas ballast assembly is matched with the exhaust assembly for exhausting, the gas ballast assembly is good in sealing performance and stable in structure, the sealing and filtering effects of the exhaust assembly are good, and the overall exhaust effect is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of vacuum pump technology, specifically relating to a freeze dryer vacuum pump and its exhaust method. Background Technology

[0002] Vacuum pumps are commonly used to extract gas from pressure vessels, thereby maintaining a vacuum state. One commonly used type of vacuum pump is the rotary vane vacuum pump, which utilizes the rotational motion of a rotor and vanes within the pump chamber to periodically change the working volume, thus continuously removing gas to achieve a vacuum. A patent with publication number CN217233800U discloses a direct-drive rotary vane vacuum pump, comprising: a bracket with a mounting hole; a rotor shaft located in the mounting hole; an oil pump cover located in the mounting hole, the oil pump cover being inserted into the mounting hole from the vane side, and the oil pump cover having a mounting groove; and an oil seal located in the mounting groove, sealing the oil pump cover and the rotor shaft. Existing vacuum pumps lack an exhaust structure on the oil tank; the exhaust structure often relies on a gas ballast assembly within the vacuum pump for exhaust, resulting in poor exhaust performance and the generation of significant oil mist during operation. Patent CN112761955A discloses a gas ballast structure for a rotary vane vacuum pump. However, the outer diameter of the rotating shaft in this existing gas ballast structure is relatively small compared to the inner diameter of the corresponding channel on the support, making the shaft prone to breakage and causing the gas ballast to fail. Furthermore, a spring between the knob and the rotating shaft poses a risk of pressure leakage when the pump body pressure is high. Additionally, the gas ballast assembly is mounted on the support via the rotating shaft, requiring complete removal for replacement, making maintenance cumbersome. Patent CN204283811U discloses an oil return structure for an oil mist filter used in a vacuum pump. However, this existing oil return structure only seals the oil passage with a single plug. During exhaust, the plug's sealing effect is poor, allowing oil mist to directly enter the oil return channel without being filtered. This results in more impurities in the exhaust gas, affecting the external environment and causing a poor user experience. Summary of the Invention

[0003] This invention addresses the problems of easy failure of gas ballasts and poor exhaust performance in existing technologies. This invention designs a vacuum pump for a freeze dryer. This invention uses a gas ballast component in conjunction with an exhaust component for exhaust. The gas ballast component has good sealing performance and a stable structure, and the exhaust component has good sealing and filtration performance, which greatly improves the overall exhaust performance.

[0004] The objective of this invention is achieved through the following technical solution: a freeze dryer vacuum pump, comprising an end cap body, with a pump body assembly and a motor assembly respectively connected to both ends of the end cap body via transmission; an oil tank housing sealed to the end cap body, the oil tank housing communicating with the internal chamber of the pump body assembly; an exhaust assembly sealed to the top of the oil tank housing, the exhaust assembly including a valve plate capable of moving up and down; and a gas ballast assembly for controlling the communication state between the flow channel inside the end cap body and the pump body assembly, the gas ballast assembly including a knob body capable of rotating relative to the end cap body.

[0005] Preferably, the pump body assembly includes a pump casing body and a primary rotor, and the motor assembly includes a motor shaft body. A coupling assembly for transmission is provided between the motor shaft body and the primary rotor. The primary rotor and the pump casing body are rotatably connected. The primary rotor is provided with a pair of first and second seals. The first seal is located between the inner side of the pump casing body and the primary rotor, and the second seal is located between the outer side of the pump casing body and the chamber of the end cover body. A friction-reducing bushing is also fitted onto the primary rotor, and the second seal is fitted onto the outer layer of the friction-reducing bushing.

[0006] Preferably, a first flow channel and a second flow channel are respectively provided between the end cap body and the pump body assembly. A solenoid valve is installed on the first flow channel, and a gas ballast assembly is installed on the second flow channel. The gas ballast assembly includes a knob body, a gas ballast sealing ring, and a gas ballast rotating shaft. The gas ballast rotating shaft is fixedly connected to the end cap body and is conductively connected to the second flow channel. A gas ballast sealing ring that can rotate relative to the gas ballast rotating shaft is sleeved on it. The gas ballast sealing ring has a first through hole for air passage. A knob body that rotates synchronously with the gas ballast sealing ring is provided on it.

[0007] Preferably, a first fastener, which is a screw, is provided between the knob body and the gas ballast shaft for fixing the two. A washer is provided between the first fastener and the end face of the knob body. The gas ballast shaft is provided with a mounting step, and the knob body and the gas ballast sealing ring are provided on the mounting step. The gas ballast shaft is provided with a second through hole that is connected to the second flow channel. When the knob body is rotated, the first through hole can rotate relative to the second through hole.

[0008] Preferably, a second fastener is provided between the gas ballast shaft and the end cap body for fixing the two; the gas ballast sealing ring is provided with a pair of limiting protrusions, and the knob body is provided with a pair of limiting grooves. When the knob body is installed on the gas ballast sealing ring, the limiting protrusions are located in the limiting grooves; the knob body is also provided with an airflow channel that communicates with the outside, and the airflow channel is oriented toward the first through hole on the gas ballast sealing ring; a limiting pin is fixedly installed on the upper end face of the end cap body, and an arc-shaped groove is provided in the knob body that faces the limiting pin.

[0009] The motor shaft drives the primary rotor to rotate via a coupling assembly, enabling the pump body assembly to operate normally. A first seal prevents hydraulic oil leakage from the pump casing. A second seal further enhances the seal between the pump casing and the end cover, preventing hydraulic oil leakage from the end cover. An anti-friction bushing prevents excessive wear of the second seal, further improving the sealing effect.

[0010] By setting up the first flow channel and the solenoid valve, the connection between the end cap body and the pump body assembly can be automatically controlled by the circuit board inside the vacuum pump. By incorporating a gas ballast assembly, dry external gas can easily enter the pump body assembly through the second flow channel, and then be easily exhausted in conjunction with the exhaust assembly, preventing water vapor from condensing inside the pump body assembly. The gas ballast shaft on the gas ballast assembly has a larger outer diameter and higher structural strength. The gas ballast shaft is fixed by a second fastener, making the connection between the gas ballast shaft and the end cap body more stable and improving the gas intake and exhaust effect. The first fastener facilitates the connection between the knob body and the gas ballast shaft, and a washer is provided to facilitate the rotation of the knob body relative to the gas ballast shaft, preventing wear on the knob body. Existing gas ballast structures have an O-ring seal between the knob body and the end cap body. Since the knob body needs to rotate, the O-ring seal is easily worn, leading to gas leakage. In this invention, the bottom of the gas ballast shaft has an annular groove, and an O-ring seal is placed in the annular groove. The O-ring seal is an existing standard part and is not shown in the drawings of the specification. The O-ring seal on the gas ballast shaft is in close contact with the inside of the second flow channel, and the gas ballast shaft does not need to rotate, thus achieving a better sealing effect. This invention employs a gas ballast sealing ring for gas path control. The gas ballast sealing ring possesses hardness and has a large contact area with the gas ballast shaft, resulting in excellent overall sealing. In the default state, the first and second through holes are misaligned, ensuring a tight seal between the inner wall of the gas ballast sealing ring and the outer wall of the gas ballast shaft. When the gas ballast assembly needs to be opened, rotating the knob body simultaneously rotates the gas ballast sealing ring. When the first and second through holes are aligned, external dry gas first enters the first through hole through the airflow channel, then enters the second through hole, then enters the bottom of the second flow channel, and finally enters the pump assembly. Here, the diameter of the first through hole is larger than that of the second through hole, and the diameter of the second through hole is relatively small, ranging from 0.2mm to 0.3mm. This ensures fast air intake and good leak-proof performance. The interplay of a limiting protrusion and a limiting groove ensures that the knob body can rotate the gas ballast sealing ring. By incorporating installation steps, the knob body can be easily positioned and installed, while maintaining a gap between the knob body and the upper surface of the end cap body. The interaction between the limiting pin and the arc-shaped groove limits the rotation angle of the knob body, ensuring alignment of the first and second through holes for easy switching of the gas ballast assembly's on / off state.

[0011] Preferably, the venting assembly is threadedly connected to the fuel tank housing. A sight glass is provided on the side of the fuel tank housing and sealed therewith. A pressure cap for fixing is provided between the sight glass and the fuel tank housing, and the pressure cap is threadedly connected to the fuel tank housing. The venting assembly includes a lower filter element cover, an upper filter element cover, a lower venting cover, an upper venting cover, and a filter element body. The lower filter element cover is threadedly connected to the fuel tank housing, and the lower venting cover is threadedly connected to the lower filter element cover. The filter element body is tightly fitted onto the lower filter element cover. The top of the filter element body is provided with a upper filter element cover tightly fitted therewith. The top of the lower venting cover is provided with a snap-fit ​​upper venting cover. A third fastener for fixing the upper venting cover and the upper filter element cover is provided between them. The top of the upper venting cover has several evenly distributed vent holes. An oil passage chamber is formed between the inner wall of the lower venting cover and the outer wall of the filter element body. A return oil channel communicating with the oil passage chamber is provided on the lower filter element cover. A valve plate that can move up and down relative to the return oil channel is also provided inside the lower filter element cover.

[0012] Preferably, the lower cover of the filter element is provided with an oil passage that connects the filter element body and the oil tank housing, and the filter element body is located between the oil passage and the oil circuit chamber; a first sealing ring is provided between the lower cover of the filter element and the lower cover of the exhaust, and a second sealing ring is provided between the lower cover of the exhaust and the oil tank housing.

[0013] Preferably, the lower cover of the filter element is further provided with a conical reflux hole, and a sealing bead is provided in the conical reflux hole. The outer contour of the sealing bead is adapted to the outer contour of the conical reflux hole. A valve plate that can move up and down relative to the bottom of the conical reflux hole is installed. A fourth fastener, which is a screw, is provided between the two ends of the valve plate and the lower cover of the filter element for fixing. The bottom of the lower cover of the filter element is provided with a pair of stepped protrusions. The fourth fastener is coaxially arranged with the stepped protrusions. The two ends of the valve plate are sleeved on the stepped protrusions, and a gap is left between the end face of the valve plate and the fourth fastener. The end face of the valve plate faces the sealing bead. The thickness of the valve plate is 0.1 mm.

[0014] By installing a sight glass, the operator can directly observe the remaining hydraulic oil level in the tank housing. A pressure cap secures the sight glass. When venting is required, the air ballast assembly is opened, allowing the sprayed hydraulic oil to diffuse directly from the oil passage into the inner wall of the filter element body, then through the filter element body into the oil circuit chamber, and finally out through the vent. During venting, the hydraulic oil has an impact force, which impacts the valve plate, causing it to adhere tightly to the bottom of the conical return orifice. Because the opening of the oil passage is large, the hydraulic oil diffuses into the passage with the larger opening. At this point, the valve plate can seal the bottom of the conical return orifice. When the oil pressure inside the tank housing is high, some hydraulic oil will pass through the valve plate and diffuse into the conical return orifice. Due to the thin valve plate and the small diameter of the conical return orifice, the hydraulic oil diffuses quickly, rapidly impacting the sealing bead. At this point, the pressure at the sealing bead is high, allowing it to seal effectively and preventing the hydraulic oil from directly diffusing along the return oil passage into the oil passage. When the gas ballast assembly is closed, hydraulic oil flows from the through-channel to the return-channel under gravity. Due to the weight of the sealing bead and valve plate, they are in a descending state, opening the conical return orifice and allowing the hydraulic oil to flow back into the tank housing. A second sealing ring improves the seal between the tank housing and the exhaust cover; a first sealing ring prevents hydraulic oil from flowing directly from the tank housing into the oil passage chamber. The valve plate is 0.1mm thick, allowing for easy vertical movement relative to the fourth fastener. A stepped protrusion provides space for valve plate movement, while the fourth fastener limits its lateral movement. The valve plate not only seals the conical return orifice but also limits the sealing bead, preventing it from falling out.

[0015] To ensure cleaner exhaust gas from the vacuum pump, minimize environmental impact, and improve user experience, a venting method using a freeze dryer vacuum pump was designed. Step 1: The motor assembly drives the pump body assembly to rotate, during which hydraulic oil circulates between the pump body assembly and the oil tank housing. Step 2: During circulation, some hydraulic oil is discharged along the venting assembly. The hydraulic oil is sprayed, first diffused through a large-diameter oil passage to the surface of the filter element body, then passes through the filter element body into the oil circuit chamber, and finally exits through the vent. Step 3: After the venting process is complete, some hydraulic oil adheres to the inner wall of the venting cover and flows towards the return oil passage under gravity. At this time, the sealing bead and valve plate are in a descending state under gravity, opening the conical return orifice, allowing the hydraulic oil to return to the oil tank housing along the conical return orifice.

[0016] Preferably, during the venting process in step two, the valve plate and the sealing bead are impacted by hydraulic oil; the valve plate is in close contact with the bottom of the conical reflux hole, and the sealing bead is in close contact with the top of the conical reflux hole, thus providing a double seal for the conical reflux hole; in step three, since the valve plate is 0.1mm thick and has weight, it can automatically fall back under the action of gravity; the upper end face of the valve plate can limit the sealing bead, preventing the sealing bead from falling out of the conical reflux hole.

[0017] By incorporating a motor assembly, the operating status of the pump body assembly can be easily controlled, and by using a solenoid valve, the connection between the end cover body and the pump body assembly can be easily controlled. An air ballast assembly is included to introduce dry external gas into the pump body assembly, resulting in drier, spray-like exhaust gas. This gas is then filtered by the filter element, resulting in cleaner exhaust. During exhaust, a double seal by a valve plate and a sealing bead keeps the conical return orifice closed. Existing return oil structures are prone to hydraulic oil leakage, as the tank housing is only sealed to the outside by a single sealing bead, posing a leakage risk. The hydraulic oil is then filtered by the filter element before being discharged, resulting in cleaner exhaust gas. During return oil operation, the air ballast assembly is closed; hydraulic oil enters the conical return orifice along the return oil channel. Here, the valve plate and sealing bead descend under gravity, fully opening the conical return orifice, allowing the hydraulic oil to automatically flow back to the tank housing. The sealing bead is prevented from falling out of the conical return orifice due to the valve plate's obstruction. The valve plate here is a metal part, which is positioned by the fourth fastener; at the same time, there is a gap between the valve plate and the conical reflux hole, which can move up and down, thereby achieving the sealing and blocking effect.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. By cooperating with the gas ballast assembly and the exhaust assembly, it is convenient to introduce dry external gas into the pump body assembly, avoiding water vapor condensation in the pump assembly; at the same time, the gas discharged through the exhaust assembly is drier; 2. Here, the gas ballast shaft of the gas ballast assembly does not need to rotate, which can avoid wear of the O-ring seal and improve the overall sealing effect; 3. The gas ballast assembly controls the gas path state through the first and second through holes, and the gas ballast seal has a large contact area and good sealing effect, thus reliably switching the on and off state of the gas ballast assembly; 4. The exhaust assembly has a filter element body inside, which can filter the discharged gas, resulting in better gas discharge effect; 5. The conical return hole is coaxially set with the lower cover of the filter element, and the valve plate and sealing bead are aligned with the oil passage, so that the valve plate and sealing bead are subjected to more uniform impact force from the hydraulic oil, resulting in better sealing effect; 6. The valve plate can not only seal the conical return hole, but also limit the sealing bead, which has good versatility. Attached Figure Description

[0019] Figure 1 This is a perspective view of the present invention; Figure 2 This is a perspective view of the hidden outer casing of the present invention; Figure 3 This is a schematic diagram of the internal structure of the present invention; Figure 4 This is a schematic diagram of the end cap body. Figure 5 This is an exploded view of the gas ballast components; Figure 6 This is a three-dimensional view of the knob body; Figure 7 This is a structural schematic diagram of the exhaust assembly and the fuel tank housing in their assembled state. Figure 8 This is a schematic diagram of the internal structure of the exhaust assembly; Figure 9 This is an exploded view of the exhaust assembly; Figure 10 for Figure 3 A magnified view of a portion of position A in the diagram; Figure 11 for Figure 5 A magnified view of a portion of position B in the diagram; Markings in the diagram: 1. End cover body; 2. Pump body assembly; 21. Pump casing body; 22. First stage rotor; 23. First seal; 24. Second seal; 25. Anti-friction bushing; 3. Motor assembly; 31. Motor shaft body; 4. Oil tank housing; 5. Exhaust assembly; 51. Valve plate; 52. Filter element lower cover; 53. Filter element upper cover; 54. Exhaust lower cover; 55. Exhaust upper cover; 56. Filter element body; 57. Third fastener; 58. Vent hole; 59. Oil passage chamber; 510. Oil return channel; 511. Oil passage; 512. First sealing ring; 513. Second sealing ring; 514. Conical... 515. Return hole; 516. Sealing bead; 517. Fourth fastener; 518. Stepped protrusion; 6. Gas ballast assembly; 61. Knob body; 62. Gas ballast sealing ring; 63. Gas ballast shaft; 64. First through hole; 65. First fastener; 66. Washer; 67. Mounting step; 68. Second through hole; 69. Second fastener; 610. Limiting protrusion; 611. Limiting groove; 612. Airflow channel; 613. Limiting pin; 614. Arc-shaped groove; 7. Coupling assembly; 8. First flow channel; 9. Second flow channel; 10. Solenoid valve; 11. Sight glass; 12. Pressure cap; 13. Annular groove. Detailed Implementation

[0020] The present invention will be further described below with reference to the embodiments illustrated in the accompanying drawings: like Figures 1 to 11As shown, this embodiment discloses a freeze dryer vacuum pump, including an end cap body 1. A pump body assembly 2 and a motor assembly 3 are respectively connected to the two ends of the end cap body 1 via transmission. An oil tank housing 4 is also provided on the end cap body 1 and is sealed to it. The oil tank housing 4 communicates with the internal chamber of the pump body assembly 2. An exhaust assembly 5 is provided on the top of the oil tank housing 4 and is sealed to it. The exhaust assembly 5 includes a valve plate 51 that can move up and down. An air ballast assembly 6 is provided on the end cap body 1 to control the communication state between the flow channel inside the end cap body 1 and the pump body assembly 2. The air ballast assembly 6 includes a knob body 61 that can rotate relative to the end cap body 1.

[0021] The pump body assembly 2 includes a pump casing body 21 and a primary rotor 22. The motor assembly 3 includes a motor shaft body 31, and a coupling assembly 7 for transmission is provided between the motor shaft body 31 and the primary rotor 22. The primary rotor 22 and the pump casing body 21 are rotatably connected. The primary rotor 22 is provided with a first seal 23 and a second seal 24 arranged in pairs. The first seal 23 is disposed between the inner side of the pump casing body 21 and the primary rotor 22, and the second seal 24 is disposed between the outer side of the pump casing body 21 and the cavity of the end cover body 1. A friction-reducing bushing 25 is also sleeved on the primary rotor 22, and the second seal 24 is sleeved on the outer layer of the friction-reducing bushing 25. A first flow channel 8 and a second flow channel 9 are respectively provided between the end cap body 1 and the pump body assembly 2. A solenoid valve 10 is installed on the first flow channel 8, and a gas ballast assembly 6 is installed on the second flow channel 9. The gas ballast assembly 6 includes a knob body 61, a gas ballast sealing ring 62, and a gas ballast rotating shaft 63. The gas ballast rotating shaft 63 is fixedly connected to the end cap body 1 and is conductively connected to the second flow channel 9. A gas ballast sealing ring 62 that can rotate relative to the gas ballast rotating shaft 63 is sleeved on the gas ballast rotating shaft 63. The gas ballast sealing ring 62 is provided with a first through hole 64 for air passage. A knob body 61 that rotates synchronously with the gas ballast sealing ring 62 is provided on the gas ballast sealing ring 62. A first fastener 65, which is a screw, is provided between the knob body 61 and the gas ballast shaft 63 for fixing the two. A washer 66 is provided between the first fastener 65 and the end face of the knob body 61. The gas ballast shaft 63 is provided with a mounting step 67, on which the knob body 61 and the gas ballast sealing ring 62 are provided. The gas ballast shaft 63 is provided with a second through hole 68 that is connected to the second flow channel 9. When the knob body 61 is rotated, the first through hole 64 can rotate relative to the second through hole 68. A second fastener 69 for fixing the gas ballast shaft 63 and the end cap body 1 is provided between them; the gas ballast sealing ring 62 is provided with a pair of limiting protrusions 610, and the knob body 61 is provided with a pair of limiting grooves 611. When the knob body 61 is installed on the gas ballast sealing ring 62, the limiting protrusions 610 are located in the limiting grooves 611; the knob body 61 is also provided with an airflow channel 612 that is connected to the outside, and the airflow channel 612 is provided facing the first through hole 64 on the gas ballast sealing ring 62; a limiting pin 613 is fixedly installed on the upper end face of the end cap body 1, and an arc-shaped groove 614 is provided in the knob body 61 facing the limiting pin 613.

[0022] The exhaust assembly 5 is threadedly connected to the fuel tank housing 4. A sight glass 11 is provided on the side of the fuel tank housing 4 and is sealed thereto. A pressure cap 12 for fixing is provided between the sight glass 11 and the fuel tank housing 4. The pressure cap 12 is threadedly connected to the fuel tank housing 4. The exhaust assembly 5 includes a lower filter element cover 52, an upper filter element cover 53, an exhaust lower cover 54, an exhaust upper cover 55, and a filter element body 56. The lower filter element cover 52 is threadedly connected to the fuel tank housing 4, and the exhaust lower cover 54 is threadedly connected to the lower filter element cover 52. The filter element body 56 is tightly fitted onto the lower filter element cover 52. The filter element cover 53 is provided at the top and is tightly connected to it. The exhaust cover 54 is provided at the top with an exhaust cover 55 that is snapped together. A third fastener 57 is provided between the exhaust cover 55 and the filter element cover 53 to fix the two together. The exhaust cover 55 is provided at the top with several evenly distributed vent holes 58. The inner wall of the exhaust cover 54 and the outer wall of the filter element body 56 surround each other to form an oil passage chamber 59. The filter element cover 52 is provided with a return oil channel 510 that is connected to the oil passage chamber 59. The filter element cover 52 is also provided with a valve plate 51 that can move up and down relative to the return oil channel 510. The filter element lower cover 52 is provided with an oil passage 511 that connects the filter element body 56 and the oil tank housing 4. The filter element body 56 is located between the oil passage 511 and the oil circuit chamber 59. A first sealing ring 512 is provided between the filter element lower cover 52 and the exhaust lower cover 54 for sealing. A second sealing ring 513 is provided between the exhaust lower cover 54 and the oil tank housing 4 for sealing. The filter element lower cover 52 is further provided with a conical reflux hole 514, and a sealing bead 515 is provided in the conical reflux hole 514. The outer contour of the sealing bead 515 is adapted to the outer contour of the conical reflux hole 514. A valve plate 51 that can move up and down relative to the bottom of the conical reflux hole 514 is installed. A fourth fastener 516 for fixing is provided between the two ends of the valve plate 51 and the filter element lower cover 52. The fourth fastener 516 is a screw. The bottom of the filter element lower cover 52 is provided with a pair of stepped protrusions 517. The fourth fastener 516 and the stepped protrusions 517 are coaxially arranged. The two ends of the valve plate 51 are sleeved on the stepped protrusions 517. A gap is left between the end face of the valve plate 51 and the fourth fastener 516. The end face of the valve plate 51 faces the sealing bead 515. The thickness of the valve plate 51 is 0.1mm.

[0023] The specific operation process of this embodiment is as follows: the motor shaft body 31 drives the first-stage rotor 22 to rotate through the coupling assembly 7, so that the pump body assembly 2 can work normally; by setting the first seal 23, hydraulic oil leakage inside the pump housing body 21 is prevented; by setting the second seal 24, the sealing between the pump housing body 21 and the end cover body 1 is improved, preventing hydraulic oil leakage from the end cover body 1. By setting the anti-friction bushing 25, excessive wear of the second seal 24 can be avoided, further improving the sealing effect.

[0024] By setting the first flow channel 8 and the solenoid valve 10, the circuit board inside the vacuum pump can automatically control the conduction state between the end cap body 1 and the pump body assembly 2. The gas ballast assembly 6 facilitates the entry of dry external gas into the pump body assembly 2 through the second flow channel 9, and then, in conjunction with the exhaust assembly 5, facilitates exhaust, preventing water vapor condensation inside the pump body assembly 2. The gas ballast shaft 63 on the gas ballast assembly 6 has a larger outer diameter and higher structural strength. The second fastener 69 secures the gas ballast shaft 63, making the connection between the gas ballast shaft 63 and the end cap body 1 more stable and improving the gas intake and exhaust effect. The first fastener 65 facilitates the connection between the knob body 61 and the gas ballast shaft 63, and the washer 66 facilitates the relative movement of the knob body 61 with the gas ballast. The rotating shaft 63 rotates to prevent wear on the knob body 61. Existing gas ballast structures have an O-ring seal between the knob body 61 and the end cap body 1. Since the knob body 61 needs to rotate, the O-ring seal is easily worn, leading to gas leakage. In this invention, the bottom of the gas ballast rotating shaft 63 has an annular groove 13, within which an O-ring seal is placed. The O-ring seal is a standard component and is not shown in the accompanying drawings. The O-ring seal on the gas ballast rotating shaft 63 is tightly fitted to the inside of the second flow channel 9, and since the gas ballast rotating shaft 63 does not need to rotate, the sealing effect is better. In this invention, a gas ballast sealing ring 62 is used for gas path control. The gas ballast sealing ring 62 has hardness, and the contact area between the gas ballast sealing ring 62 and the gas ballast rotating shaft 63 is large, resulting in a good overall sealing effect. In the default state, the first through hole 64 and the second through hole 68 are misaligned, so that the inner wall of the gas ballast sealing ring 62 fits tightly against the outer wall of the gas ballast rotating shaft 63, thereby achieving a seal. When the gas ballast assembly 6 needs to be opened, the knob body 61 is rotated, and the knob body 61 simultaneously drives the gas ballast sealing ring 62 to rotate. When the first through hole 64 and the second through hole 68 are aligned, the external dry gas first enters the first through hole 64 through the airflow channel 612, then enters the second through hole 68 from the first through hole 64, then enters the bottom of the second flow channel 9 from the second through hole 68, and then enters the pump body assembly 2. Here, the diameter of the first through hole 64 is larger than the diameter of the second through hole 68, and the diameter range of the second through hole 68 is small, set between 0.2mm and 0.3mm, so that the air intake speed is fast and the air leakage prevention effect is good. The limiting protrusion 610 and the limiting groove 611 cooperate with each other to ensure that the knob body 61 can drive the gas ballast sealing ring 62 to rotate. The installation step 67 is provided to facilitate the positioning and installation of the knob body 61, while leaving a gap between the knob body 61 and the upper end face of the end cover body 1. The limiting pin 613 and the arc-shaped groove 614 cooperate to limit the rotation angle of the knob body 61, ensuring that the first through hole 64 and the second through hole 68 can be aligned, which facilitates switching the on / off state of the gas ballast assembly 6.

[0025] By setting a sight glass 11, the operator can easily observe the remaining amount of hydraulic oil in the oil tank housing 4. A pressure cap 12 is used to fix the sight glass 11 in place. When venting is required, the air ballast assembly 6 is opened, allowing the sprayed hydraulic oil to diffuse directly from the oil passage 511 into the inner wall of the filter element body 56, then through the filter element body 56 into the oil circuit chamber 59, and finally out through the vent hole 58. During venting, the hydraulic oil has an impact force, which impacts the valve plate 51, causing the valve plate 51 to adhere tightly to the bottom of the conical return hole 514. Because the opening of the oil passage 511 is relatively large, Hydraulic oil diffuses into the larger opening of the oil passage 511; at this time, the valve plate 51 can seal the bottom of the conical return hole 514; when the oil pressure inside the tank shell 4 is high, some hydraulic oil will pass through the valve plate 51 and diffuse into the conical return hole 514; because the valve plate 51 is thin and the diameter of the conical return hole 514 is small, the hydraulic oil diffuses quickly, and the hydraulic oil will quickly impact the sealing bead 515; at this time, the pressure at the location of the sealing bead 515 is high, and the sealing bead 515 can seal well, preventing the hydraulic oil from directly diffusing into the oil passage 511 along the return oil passage 510. When the gas ballast assembly 6 is closed, hydraulic oil flows from the oil passage 511 to the return oil passage 510 under the action of gravity. Since both the sealing bead 515 and the valve plate 51 have their own weight, they are in a descending state, thus opening the conical return orifice 514, allowing the hydraulic oil to flow back into the oil tank housing 4 along it. The second sealing ring 513 improves the sealing between the oil tank housing 4 and the exhaust cover; the first sealing ring 512 prevents hydraulic oil from flowing directly from the oil tank housing 4 into the oil circuit chamber 59. The valve plate 51 has a thickness of 0.1mm, allowing for easy vertical movement relative to the fourth fastener 516. A stepped protrusion 517 provides space for the valve plate 51 to move up and down, while the fourth fastener 516 limits its lateral movement. Here, the valve plate 51 can not only seal the conical reflux hole 514, but also limit the sealing bead 515 to prevent the sealing bead 515 from falling out of the conical reflux hole 514.

[0026] To ensure cleaner exhaust gas from the vacuum pump, avoid impacting the external environment, and improve user experience, a venting method using a freeze dryer vacuum pump was designed. Step 1: The motor assembly 3 drives the pump body assembly 2 to rotate. During this rotation, hydraulic oil circulates between the pump body assembly 2 and the oil tank housing 4. Step 2: During circulation, some hydraulic oil is discharged along the venting assembly 5. At this time, the hydraulic oil is in a spray form, first diffusing through the large-diameter oil passage 511 to the surface of the filter element body 56, then passing through the filter element body 56 into the oil circuit chamber 59, and finally exiting from the vent 58. Step 3: After the venting process is complete, some hydraulic oil adheres to the inner wall of the venting cover 54 and flows towards the return oil passage 510 under gravity. At this time, under gravity, the sealing bead 515 and valve plate 51 are in a descending state, thus opening the conical return hole 514, allowing the hydraulic oil to return to the oil tank housing 4 along the conical return hole 514.

[0027] During the venting process in step two, the valve plate 51 and the sealing bead 515 are impacted by hydraulic oil; the valve plate 51 is in close contact with the bottom of the conical reflux hole 514, and the sealing bead 515 is in close contact with the top of the conical reflux hole 514, thus providing a double seal for the conical reflux hole 514; in step three, since the valve plate 51 is 0.1mm thick and has weight, the valve plate 51 can automatically fall back under the action of gravity; the upper end face of the valve plate 51 can limit the sealing bead 515, preventing the sealing bead 515 from falling out of the conical reflux hole 514.

[0028] By setting up the motor assembly 3, the working state of the pump body assembly 2 can be easily controlled, and by setting up the solenoid valve 10, the conduction state between the end cover body 1 and the pump body assembly 2 can be easily controlled. Here, the gas ballast assembly 6 is set up to introduce dry external gas into the pump body assembly 2, making the discharged gas drier and in a spray form. After being filtered by the filter element body 56, the discharged gas is cleaner. During exhaust, the conical return orifice 514 is closed by a double seal of the valve plate 51 and the sealing bead 515. In existing oil return structures, hydraulic oil is prone to leakage, as the oil tank housing 4 is only sealed to the outside by a single sealing bead 515, posing a leakage risk. The hydraulic oil is then filtered by the filter element body 56 before being discharged, resulting in cleaner discharged gas. When returning oil, the gas ballast assembly 6 is closed; hydraulic oil enters the conical return orifice 514 along the return oil channel 510; here, the valve plate 51 and the sealing bead 515 are in a descending state under the action of gravity, the conical return orifice 514 is fully open, and the hydraulic oil automatically flows back to the oil tank housing 4 from the conical return orifice 514; due to the obstruction by the valve plate 51, the sealing bead 515 will not fall out of the conical return orifice 514. Here, the valve plate 51 is a metal part, which is positioned by the fourth fastener 516; at the same time, there is a gap between the valve plate 51 and the conical return orifice 514, which can move up and down, thereby achieving the sealing and obstruction effect.

[0029] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A freeze dryer vacuum pump, comprising an end cap body (1), characterized in that, The end cap body (1) is provided with a pump body assembly (2) and a motor assembly (3) respectively connected by transmission at both ends. The end cap body (1) is also provided with an oil tank housing (4) which is sealed to it. The oil tank housing (4) is connected to the internal chamber of the pump body assembly (2). The top of the oil tank housing (4) is provided with an exhaust assembly (5) which is sealed to it. The exhaust assembly (5) includes a valve plate (51) that can move up and down. The end cap body (1) is provided with a gas ballast assembly (6) for controlling the communication state between the flow channel inside the end cap body (1) and the pump body assembly (2). The gas ballast assembly (6) includes a knob body (61) that can rotate relative to the end cap body (1).

2. The freeze dryer vacuum pump according to claim 1, characterized in that, The pump body assembly (2) includes a pump casing body (21) and a first-stage rotor (22). The motor assembly (3) includes a motor shaft body (31). A coupling assembly (7) for transmission is provided between the motor shaft body (31) and the first-stage rotor (22). The first-stage rotor (22) and the pump casing body (21) are rotatably connected. The first-stage rotor (22) is provided with a first seal (23) and a second seal (24) arranged in pairs. The first seal (23) is located between the inner side of the pump casing body (21) and the first-stage rotor (22). The second seal (24) is located between the outer side of the pump casing body (21) and the chamber of the end cover body (1). A friction-reducing bushing (25) is also sleeved on the first-stage rotor (22). The second seal (24) is sleeved on the outer layer of the friction-reducing bushing (25).

3. The freeze dryer vacuum pump according to claim 1, characterized in that, The end cap body (1) and the pump body assembly (2) are respectively provided with a first flow channel (8) and a second flow channel (9). A solenoid valve (10) is installed on the first flow channel (8), and a gas ballast assembly (6) is installed on the second flow channel (9). The gas ballast assembly (6) includes a knob body (61), a gas ballast sealing ring (62) and a gas ballast rotating shaft (63). The gas ballast rotating shaft (63) is fixedly connected to the end cap body (1), and the gas ballast rotating shaft (63) is connected to the second flow channel (9). A gas ballast sealing ring (62) that can rotate relative to the gas ballast rotating shaft (63) is sleeved on the gas ballast rotating shaft (63). A first through hole (64) for air passage is provided on the gas ballast sealing ring (62). A knob body (61) that rotates synchronously with the gas ballast sealing ring (62) is provided on the gas ballast sealing ring (62).

4. The freeze dryer vacuum pump according to claim 3, characterized in that, A first fastener (65) for fixing the knob body (61) and the gas ballast shaft (63) is provided between the knob body (61) and the gas ballast shaft (63). The first fastener (65) is a screw. A washer (66) is provided between the first fastener (65) and the end face of the knob body (61). An installation step (67) is provided on the gas ballast shaft (63). The knob body (61) and the gas ballast sealing ring (62) are provided on the installation step (67). A second through hole (68) is provided on the gas ballast shaft (63) and communicates with the second flow channel (9). When the knob body (61) is rotated, the first through hole (64) can rotate relative to the second through hole (68).

5. The freeze dryer vacuum pump according to claim 4, characterized in that, A second fastener (69) for fixing the gas ballast shaft (63) and the end cap body (1) is provided; the gas ballast sealing ring (62) is provided with a pair of limiting protrusions (610), and the knob body (61) is provided with a pair of limiting grooves (611). When the knob body (61) is installed on the gas ballast sealing ring (62), the limiting protrusions (610) are located in the limiting grooves (611); the knob body (61) is also provided with an airflow channel (612) that is connected to the outside, and the airflow channel (612) is provided facing the first through hole (64) on the gas ballast sealing ring (62); a limiting pin (613) is fixedly installed on the upper end face of the end cap body (1), and an arc-shaped groove (614) is provided in the knob body (61) facing the limiting pin (613).

6. The freeze dryer vacuum pump according to claim 1, characterized in that, The exhaust assembly (5) is threadedly connected to the oil tank housing (4). A sight glass (11) is provided on the side of the oil tank housing (4) and sealed thereto. A pressure cap (12) for fixing is provided between the sight glass (11) and the oil tank housing (4). The pressure cap (12) is threadedly connected to the oil tank housing (4). The exhaust assembly (5) includes a filter element lower cover (52), a filter element upper cover (53), an exhaust lower cover (54), an exhaust upper cover (55), and a filter element body (56). The filter element lower cover (52) is threadedly connected to the oil tank housing (4). The exhaust lower cover (54) is threadedly connected to the filter element lower cover (52). The filter element body (56) is tightly fitted on the filter element lower cover (52). The top of (56) is provided with a filter element cover (53) that is tightly connected to it. The top of the exhaust cover (54) is provided with an exhaust cover (55) that is snapped together. A third fastener (57) is provided between the exhaust cover (55) and the filter element cover (53) for fixing the two. The top of the exhaust cover (55) is provided with several evenly distributed vent holes (58). The inner wall of the exhaust cover (54) and the outer wall of the filter element body (56) surround each other to form an oil passage chamber (59). The filter element cover (52) is provided with a return oil channel (510) that is connected to the oil passage chamber (59). The filter element cover (52) is also provided with a valve plate (51) that can move up and down relative to the return oil channel (510).

7. The freeze dryer vacuum pump according to claim 6, characterized in that, The filter element lower cover (52) is provided with an oil passage (511) that connects the filter element body (56) and the oil tank housing (4). The filter element body (56) is provided between the oil passage (511) and the oil circuit chamber (59). A first sealing ring (512) for sealing is provided between the filter element lower cover (52) and the exhaust lower cover (54). A second sealing ring (513) for sealing is provided between the exhaust lower cover (54) and the oil tank housing (4).

8. The freeze dryer vacuum pump according to claim 6, characterized in that, The filter element lower cover (52) is also provided with a conical reflux hole (514), and a sealing bead (515) is provided in the conical reflux hole (514). The outer contour of the sealing bead (515) is adapted to the outer contour of the conical reflux hole (514). A valve plate (51) that can move up and down relative to the bottom of the conical reflux hole (514) is installed. A fourth fastener (516) for fixing is provided between the two ends of the valve plate (51) and the filter element lower cover (52). The component (516) is a screw; the bottom of the filter element cover (52) is provided with a pair of stepped protrusions (517), and the fourth fastener (516) is coaxially arranged with the stepped protrusions (517); the two ends of the valve plate (51) are sleeved and installed on the stepped protrusions (517), and there is a gap between the end face of the valve plate (51) and the fourth fastener (516); the end face of the valve plate (51) is arranged facing the sealing bead (515); the thickness of the valve plate (51) is 0.1mm.

9. A method for venting exhaust using a freeze dryer vacuum pump as described in any one of claims 1-8, characterized in that, Step 1: The motor assembly (3) drives the pump body assembly (2) to rotate. When the pump body assembly (2) rotates, the hydraulic oil circulates between the pump body assembly (2) and the oil tank housing (4). Step 2: During the circulation process, some of the hydraulic oil is discharged along the exhaust assembly (5). At this time, the hydraulic oil is sprayed. The hydraulic oil first diffuses to the surface of the filter element body (56) through the large-diameter oil passage (511), then passes through the filter element body (56) and enters the oil circuit chamber (59), and finally is discharged from the vent hole (58). Step 3: After the exhaust process is completed, some of the hydraulic oil will adhere to the inner wall of the exhaust cover (54) and flow to the return oil passage (510) under the action of gravity. At this time, under the action of gravity, the sealing bead (515) and the valve plate (51) are in a downward state, so the conical return hole (514) is in an open state, and the hydraulic oil can return to the oil tank housing (4) along the conical return hole (514).

10. The exhaust method using a freeze dryer vacuum pump according to claim 9, characterized in that, During the venting process in step two, the valve plate (51) and the sealing bead (515) are impacted by hydraulic oil; the valve plate (51) is close to the bottom of the conical reflux hole (514), and the sealing bead (515) is close to the top of the conical reflux hole (514), thus providing a double seal for the conical reflux hole (514); in step three, since the valve plate (51) is 0.1mm thick and has weight, the valve plate (51) can automatically fall back under the action of gravity; the upper end face of the valve plate (51) can limit the sealing bead (515) to prevent the sealing bead (515) from falling out of the conical reflux hole (514).

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