A negative pressure vacuum pump

Abstract

This invention relates to the field of energy-saving vacuum pump technology, particularly negative pressure vacuum pumps, including a support assembly comprising a bracket; a pump body comprising a cylinder fixed to the top of the bracket and piston rings reciprocating inside the cylinder; and an intake assembly comprising an intake valve connected to the intake port of the cylinder, an outer tube fixed to the intake port of the intake valve, a venturi tube fixed inside the outer tube, and a composite filter element cooperating within the venturi tube's diffuser. By extending the gas's time within the composite filter element and employing a two-stage "coarse filtration-adsorption" protection system, filtration efficiency is improved, preventing contaminants from entering the vacuum pump and thus reducing frictional resistance and ineffective energy consumption. Furthermore, by significantly shortening the maintenance and replacement time of the intake assembly, the downtime of the vacuum pump due to maintenance is reduced, ultimately lowering the "start-up inrush current" energy consumption after shutdown and the probability of using the backup pump, achieving energy-saving effects.

Description

Technical Field

[0001] This invention relates to the field of energy-saving vacuum pump technology, and in particular to a negative pressure vacuum pump. Background Technology

[0002] Negative pressure vacuum pumps are widely used in many fields such as industry, medicine, and laboratories. They extract gas from a closed space through mechanical or physical means to reduce the internal pressure and create a negative pressure environment. As a key component of negative pressure vacuum pumps, the air inlet filter has a crucial impact on the performance, service life, and operational stability of the vacuum pump.

[0003] Traditional negative pressure vacuum pumps use simple cylindrical shells and single filter media for their inlet filters, which typically means a sluggish filtration process. This affects the filter's efficiency and leads to poor maintenance. On the one hand, reduced filtration efficiency allows dust, oil mist, and other contaminants to enter the vacuum pump. These contaminants accumulate in the gaps between moving parts such as pistons, increasing frictional resistance and resulting in wasted electrical energy to overcome the extra friction. On the other hand, reduced efficiency and poor maintenance can lead to prolonged downtime due to maintenance, ultimately increasing the "start-up inrush current" energy consumption after restarting and the probability of using the backup pump, which is not conducive to energy conservation. This paper aims to design a new type of negative pressure vacuum pump to overcome the shortcomings of existing technologies. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the above or prior art, the present invention is proposed.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a negative pressure vacuum pump, comprising,

[0007] Support components, including a bracket;

[0008] The pump body includes a cylinder body fixed to the top of a bracket, and piston rings that reciprocate inside the cylinder body.

[0009] The intake assembly includes an intake valve connected to the intake port of the cylinder block, an outer tube fixed to the intake port of the intake valve, a venturi tube fixed inside the outer tube, a composite filter element fitted inside the venturi tube diffuser, a base frame abutting the bottom of the composite filter element, a spring abutting the bottom of the base frame, a sealing ring abutting the top of the composite filter element, and support rods arranged in a ring array and inserted inside the composite filter element.

[0010] The bottom of the spring abuts against the air inlet of the intake valve, the bottom end of the support rod is fixed to the base frame, the top end of the support rod is fixed to the sealing ring, and the outside of the sealing ring abuts against the junction of the venturi tube's diffuser and throat; and

[0011] An exhaust assembly, which includes an exhaust valve connected to the exhaust port of the cylinder block.

[0012] As a preferred embodiment of the negative pressure vacuum pump of the present invention, the support assembly further includes protective covers fixed to both sides of the bracket and casters fixed to the bottom of the bracket.

[0013] As a preferred embodiment of the negative pressure vacuum pump of the present invention, the pump body further includes a piston rod fixed to the center of the piston ring, and a guide frame sliding outside the piston rod, the guide frame being fixed to the bottom port of the cylinder body.

[0014] As a preferred embodiment of the negative pressure vacuum pump of the present invention, it further includes a drive source, which includes a motor fixed on a bracket, a crank fixed on a motor drive shaft, and a connecting rod rotating on the crank, with one end of the connecting rod away from the crank rotatably connected to the bottom end of the piston rod.

[0015] As a preferred embodiment of the negative pressure vacuum pump of the present invention, the composite filter element is shaped as a frustum-shaped cone that matches the inner cavity of the venturi tube's expanding tube. The composite filter element includes a meltblown cloth filter element and an activated carbon filter paper filter element. The activated carbon filter paper filter element covers the outside of the meltblown cloth filter element. The top port of the activated carbon filter paper filter element is covered by the bottom of the sealing ring, and the inner hole of the sealing ring is aligned with the top of the meltblown cloth filter element.

[0016] As a preferred embodiment of the negative pressure vacuum pump of the present invention, the exhaust assembly further includes an aluminum alloy gas storage tank connected to the exhaust valve outlet, and a pressure gauge fixed on the aluminum alloy gas storage tank, wherein the aluminum alloy gas storage tank is fixedly installed inside the bracket.

[0017] In a preferred embodiment of the negative pressure vacuum pump of the present invention, both the inlet valve and the exhaust valve are one-way valves.

[0018] In a preferred embodiment of the negative pressure vacuum pump of the present invention, both the outer tube and the venturi tube are made of transparent material.

[0019] The beneficial effects of the negative pressure vacuum pump of this invention are as follows: By using a venturi tube, the residence time of gas in the composite filter element is extended, significantly improving the filtration efficiency and ensuring the stable and efficient operation of the negative pressure vacuum pump. The meltblown cloth and activated carbon filter paper are composited in multiple layers to form a two-stage protection system of "coarse filtration-adsorption". The spring force makes the sealing ring tightly abut against the inner wall of the venturi tube, which facilitates the removal, replacement and disassembly of the composite filter element and greatly shortens the maintenance and replacement time of the air intake component. The above design, on the one hand, inhibits the entry of contaminants into the vacuum pump, which leads to increased frictional resistance and increased ineffective energy consumption. On the other hand, it shortens the downtime of the vacuum pump due to maintenance, and ultimately reduces the energy consumption of the "start-up inrush current" after restarting after shutdown, as well as the probability of using the standby pump, thus achieving energy saving effect. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a negative pressure vacuum pump.

[0022] Figure 2 This is a schematic diagram of the cylinder assembly for a negative pressure vacuum pump.

[0023] Figure 3 This is an exploded view of the pump body structure of a negative pressure vacuum pump.

[0024] Figure 4 This is a schematic diagram of the air intake assembly of a negative pressure vacuum pump.

[0025] Figure 5 for Figure 4 A cross-sectional view at point AA.

[0026] Figure 6 for Figure 4 A structural decomposition diagram.

[0027] Figure 7 This is a simplified schematic diagram of the composite filter element structure.

[0028] Figure 8 This is a schematic diagram of the drive source assembly for a negative pressure vacuum pump.

[0029] In the diagram: 100, support assembly; 200, pump body; 300, drive source; 400, intake assembly; 500, exhaust assembly;

[0030] 101. Bracket; 102. Protective cover; 103. Casters;

[0031] 201. Cylinder block; 202. Piston ring; 203. Piston rod; 204. Guide bracket;

[0032] 301. Electric motor; 302. Crank; 303. Connecting rod;

[0033] 401. Inlet valve; 402. Outer tube; 403. Venturi tube; 404. Composite filter element; 4041. Meltblown cloth filter element; 4042. Activated carbon filter paper filter element; 405. Base frame; 406. Support rod; 407. Sealing ring; 408. Spring;

[0034] 501. Exhaust valve; 502. Aluminum alloy gas storage tank; 503. Pressure gauge. Detailed Implementation

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0036] Reference Figures 1 to 8 This embodiment of the present invention provides a negative pressure vacuum pump, including a support assembly 100, which includes a bracket 101. The support assembly 100 also includes protective covers 102 fixed to both sides of the bracket 101 and casters 103 fixed to the bottom of the bracket 101. The protective covers 102 are used to protect the equipment in operation and prevent damage from external impacts, while the casters 103 facilitate the transfer of the device and improve the convenience of use.

[0037] Furthermore, refer to Figures 1-3 The negative pressure vacuum pump also includes a pump body 200, which includes a cylinder body 201 fixed to the top of the bracket 101 and a piston ring 202 that reciprocates inside the cylinder body 201.

[0038] In this embodiment, the vacuum pump operates as a reciprocating piston pump. By using the piston ring 202, which reciprocates inside the cylinder 201, the volume inside the cylinder 201 is periodically changed. This achieves the effect of using negative pressure to remove air from the target area to achieve a vacuum when expanding the volume, and expelling the extracted gas from the cylinder 201 when compressing the volume, thereby realizing the purpose of negative pressure vacuum.

[0039] Reference Figures 1-3The pump body 200 also includes a piston rod 203 fixed to the center of the piston ring 202, and a guide frame 204 sliding outside the piston rod 203. The guide frame 204 is fixed at the bottom port of the cylinder body 201. In order to maintain the stability of the reciprocating motion of the piston ring 202, the guide frame 204 restricts the direction of movement of the piston rod 203, thereby reducing the wear between the piston ring 202 and the cylinder body when the piston ring 202 deviates and improving the service life. In this embodiment, the piston ring 202 is made of oil-free self-lubricating material, and the hardness of the hard layer on the inner surface of the cylinder body 201 is HV0.1>420 or higher, thereby achieving the effect of ensuring sealing performance and product life.

[0040] Furthermore, refer to Figure 1 and Figure 8 The negative pressure vacuum pump also includes a drive source 300, which includes a motor 301 fixed on the bracket 101, a crank 302 fixed on the drive shaft of the motor 301, and a connecting rod 303 rotating on the crank 302. The end of the connecting rod 303 away from the crank 302 is rotatably connected to the bottom end of the piston rod 203. In this embodiment, the crank 302 and the connecting rod 303 form a common reciprocating motion drive structure. When the motor 301 drives the crank 302 to rotate, the crank 302 will drive the connecting rod 303 to make a circular motion. Thus, when the piston rod 203 is restricted in direction by the guide frame 204, the piston ring 202 can be made to reciprocate inside the cylinder 201 by the drive of the connecting rod 303, thereby achieving the purpose of periodically changing the volume of the cylinder 201.

[0041] Reference Figures 4-6 The negative pressure vacuum pump also includes an intake assembly 400, which includes an intake valve 401 connected to the intake port of the cylinder body 201, an outer tube 402 fixed to the intake port of the intake valve 401, a venturi tube 403 fixed inside the outer tube 402, a composite filter element 404 fitted inside the diffuser of the venturi tube 403, a base frame 405 abutting against the bottom of the composite filter element 404, a spring 408 abutting against the bottom of the base frame 405, a sealing ring 407 abutting against the top of the composite filter element 404, and support rods 406 arranged in a ring array and inserted inside the composite filter element 404.

[0042] The bottom of the spring 408 abuts against the air inlet of the air inlet valve 401, the bottom end of the support rod 406 is fixed to the base frame 405, the top end of the support rod 406 is fixed to the sealing ring 407, and the outside of the sealing ring 407 abuts against the junction of the venturi tube 403's diffuser and throat.

[0043] In this embodiment, the composite filter element 404 is supported by a rigid structure consisting of a support rod 406 and a base frame 405, which can prevent severe deformation when impacted by airflow, thus avoiding air leakage. Furthermore, during connection, the air inlet structure of the air inlet valve 401 compresses the spring 408, causing the base frame 405 to be pressed towards the bottom port of the venturi tube 403 by the spring 408. The pressing force is transmitted through the support rod 406, causing the sealing ring 407 to tightly abut against the inner wall of the venturi tube 403, thereby ensuring the airtightness between the composite filter element 404 and the venturi tube 403, and also facilitating the removal, placement, and replacement of the composite filter element 404.

[0044] It should be noted that the aforementioned Venturi tube 403 utilizes existing mature technology. The Venturi tube 403 you mentioned consists of three interconnected structures, formally named the converging tube (conical contraction section), the diverging tube (conical diffusion section), and the throat (cylindrical throat). Specifically, in this embodiment, the converging tube (conical contraction section) is located at the top inlet of the Venturi tube 403, that is, the flared tube away from the cylinder block 201. It is typically a conical tube with a cone angle of approximately 21°±2°, its function being to gradually accelerate the fluid as it passes through, increasing the flow velocity. According to Bernoulli's principle, the static pressure energy of the fluid is converted into kinetic energy, thereby causing a decrease in fluid pressure; the throat (cylindrical throat)... The throat (located after the converging tube) is a short, straight pipe section with a small diameter, typically about 1 / 3 to 1 / 4 of the inlet diameter, and a length equal to the pipe diameter. Its function is to maximize the fluid velocity and minimize the pressure at this point. When measuring the flow rate, the fluid flow rate can be calculated by measuring the pressure difference between the throat and the inlet, combined with other parameters. The diffuser (conical diffuser section) is connected after the throat, which is the horn tube near the cylinder block 201. It is conical in shape, with a diffusion angle of generally 7° to 15°. Its function is to gradually decelerate the fluid as it passes through, reducing the flow velocity and gradually converting kinetic energy into static pressure energy, thereby gradually restoring the fluid pressure, reducing turbulence, and lowering the head loss.

[0045] Furthermore, the composite filter element 404 is shaped like a frustum to match the inner cavity of the venturi tube 403. The composite filter element 404 includes a meltblown cloth filter element 4041 and an activated carbon filter paper filter element 4042. The activated carbon filter paper filter element 4042 covers the outside of the meltblown cloth filter element 4041. The top port of the activated carbon filter paper filter element 4042 is covered by the bottom of the sealing ring 407, and the inner hole of the sealing ring 407 is aligned with the top of the meltblown cloth filter element 4041.

[0046] Reference Figure 7To facilitate understanding of the structure of the composite filter element 404, a simplified description is provided below, using a practical reference. In this embodiment, the composite filter element 404 can be understood by referring to the structure of a breakfast shumai (steamed dumpling). It consists of an outer bag-shaped covering and an inner filling. The top end of the covering is open, and the filling fills the covering and its top is flush with the top opening of the covering. Specifically, in this device, the activated carbon filter paper filter element 4042 is the bag-shaped covering with an opening at the top, and the meltblown fabric filter element 4041 is the filling, with its top flush with the opening. The bottom end of the sealing ring 407 completely seals the top end of the activated carbon filter paper filter element 4042. The inner hole of the sealing ring 407... Aligned with the top of the meltblown fabric filter element 4041, meaning the top of the meltblown fabric filter element 4041 is exposed below the bottom port of the throat of the venturi tube 403 through the inner hole of the sealing ring 407, this design ensures that after the gas enters the throat of the venturi tube 403, it can only flow into the meltblown fabric filter element 4041 when it flows out. In this embodiment, the meltblown fabric is electret treated to intercept large particles by electrostatic adsorption, and its fluffy structure reduces the air intake resistance, making vacuuming smoother. The activated carbon filter paper element 4042 is made of coconut shell activated carbon impregnated filter paper. Through precise weight and pore size distribution design, it effectively controls the increase in air intake resistance while ensuring adsorption capacity, which is a major improvement over the performance of traditional activated carbon filter elements.

[0047] In this embodiment, the outer pipe 402 is connected to the target object. When the pump body 200 generates negative pressure in the aforementioned connecting pipe, the gas inside the target object will be "drawn" into the air intake assembly 400 under pressure. The gas will sequentially pass through the converging tube, throat, and diverging tube of the Venturi tube 403. As described above, the converging tube of the Venturi tube 403 gradually accelerates the incoming gas, increasing its flow rate. According to Bernoulli's principle, static pressure energy is converted into kinetic energy, and the pressure decreases. This characteristic can be used to initially separate larger particulate impurities in the gas, making them easier to intercept under inertial action. The gas flow rate is the highest and the pressure is the lowest at the throat, which can enhance the adsorption force on fine impurities. At the same time, it can assist in the intake of a small amount of purification medium to mix with the gas, improving the initial purification effect and facilitating more accurate subsequent measurement of gas flow to understand the filtration situation (here, it is necessary to measure the gas flow rate more accurately at the throat). A bypass pipe is connected to the side of the tube to form a tee pipe (this is a common application of the Venturi tube 403 technology, which will not be elaborated here); the diffuser gradually slows down the gas, converting kinetic energy into static pressure energy, and the pressure gradually recovers, reducing turbulence and head loss, allowing the gas to pass smoothly through the composite filter element 404, extending the service life of the filter material, and allowing the gas to fully contact the filter material during the slowdown process, improving filtration efficiency, and ultimately providing cleaner intake air for the vacuum pump, reducing the wear and damage of impurities to the pump body. Through the use of the Venturi tube 403, the residence time of the gas in the composite filter element 404 is extended from the conventional 0.1s to 0.3s, significantly improving the adsorption efficiency of harmful gases. Through the above design, the composite filter element 404 achieves multiple functions of flow rate regulation, particle filtration and adsorption enhancement, ensuring the stable and efficient operation of the negative pressure vacuum pump.

[0048] Reference Figure 1 The negative pressure vacuum pump also includes an exhaust assembly 500, which includes an exhaust valve 501 connected to the exhaust port of the cylinder block 201.

[0049] The exhaust assembly 500 also includes an aluminum alloy gas storage tank 502 connected to the outlet of the exhaust valve 501, and a pressure gauge 503 fixed on the aluminum alloy gas storage tank 502. The aluminum alloy gas storage tank 502 is fixedly installed inside the bracket 101. The extracted gas is temporarily stored in the aluminum alloy gas storage tank 502. On the one hand, this can prevent the leakage of harmful gas and thus avoid secondary pollution. On the other hand, the high-pressure gas stored in the aluminum alloy gas storage tank 502 can also be used as a gas source for pneumatic equipment under safe conditions, thereby achieving energy reuse and energy saving.

[0050] In this embodiment, both the intake valve 401 and the exhaust valve 501 are one-way valves. Obviously, the intake valve 401 can only allow gas to flow into the cylinder body 201, and the exhaust valve 501 can only allow gas to flow out of the cylinder body 201. It should be noted that the vacuum pump needs to maintain a high vacuum, so the sealing requirements are naturally very high. When using this device, an appropriate type of one-way valve should be selected to meet different airtightness requirements. For example, if a valve plate type one-way valve is used, the sealing between the intake and exhaust valves on the valve plate and the valve plate is very important. The valve plate should be ground with high precision, and the valve plate should also undergo a 72-hour precision polishing process to achieve reliable airtightness.

[0051] Furthermore, to improve the ease of use of the device, the air intake filter, i.e., the air intake assembly 400, can adopt a transparent shell. This allows for direct observation of the usage status of the composite filter element 404, achieving the effect of timely cleaning or replacement of the composite filter element 404. In this case, both the outer tube 402 and the venturi tube 403 should be made of transparent materials. Specifically, in this embodiment, both can be made of high-transmittance, high-strength polycarbonate PC, acrylic PMMA, or polypropylene PP, or polyvinylidene fluoride PVDF materials. When their thickness is ≥5mm, they can withstand radial pressure under a negative pressure environment of 0.15MPa, while also facilitating 360° observation of the contamination status of the composite filter element 404 by the operator. In practice, observation markings can be printed on the outer tube 402. For example, a three-color warning ring (green, yellow, and red) can be printed on the surface of the outer tube 402, corresponding to the filter element cleanliness level. For example, green: pressure difference < 100Pa, normal; yellow: 100Pa ≤ pressure difference < 300Pa, pre-cleaning required; red: pressure difference ≥ 300Pa, forced replacement. This can be combined with an LED ring light built into the outer tube 402, with white light on, yellow light flashing, and red light on, to achieve visual status warning. Of course, the above is only a relatively simple and convenient measure that can be implemented. For more precise monitoring, various sensors and vision devices can be used. These are all existing technologies and will not be elaborated on here.

[0052] In this embodiment, by improving filtration efficiency, pollutants such as dust and oil mist can be effectively blocked from entering the pump. On the one hand, this reduces the problem of increased frictional resistance caused by the accumulation of pollutants in the gaps between moving parts such as piston ring 202, and avoids the pump body 200 consuming ineffective electrical energy to overcome additional friction, thus achieving "resistance reduction and energy saving". On the other hand, it can prevent pollutants from clogging the internal air passage, ensuring that the pumping efficiency is always at the design peak, avoiding inefficient energy consumption caused by the need to extend the operating time due to the decrease in pumping efficiency, thus achieving "efficiency improvement and energy saving".

[0053] Furthermore, by compressing the spring 408 through the air inlet structure of the air inlet valve 401 during connection, the sealing ring 407 is tightly pressed against the inner wall of the venturi tube 403 by the elastic force of the spring 408, thereby ensuring the airtightness between the composite filter element 404 and the venturi tube 403. This also facilitates the removal, placement, and replacement of the composite filter element 404, significantly shortening the maintenance and replacement time of the air inlet assembly 400, reducing the long-term downtime of the vacuum pump due to maintenance, reducing the energy consumption of the "start-up inrush current" after shutdown and the probability of the backup pump being activated. Ultimately, by reducing the energy consumption of shutdown / start-stop, the optimal operating state of the vacuum pump with long-term low resistance and low power consumption is maintained, thus jointly achieving the energy-saving goal of reducing total power consumption.

[0054] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A negative pressure vacuum pump characterized by: The system includes a support assembly (100) comprising a bracket (101); a pump body (200) comprising a cylinder body (201) fixed to the top of the bracket (101) and piston rings (202) reciprocating inside the cylinder body (201); and an intake assembly (400) comprising an intake valve (401) connected to the intake port of the cylinder body (201), an outer tube (402) fixed to the intake port of the intake valve (401), and a venturi tube (403) fixed inside the outer tube (402). The composite filter element (404) is fitted inside the venturi tube (403) and diffuser tube, with a base frame (405) abutting the bottom of the composite filter element (404), a spring (408) abutting the bottom of the base frame (405), a sealing ring (407) abutting the top of the composite filter element (404), and support rods (406) arranged in a ring array inside the composite filter element (404); wherein, the bottom of the spring (408) abuts the air inlet of the air inlet valve (401), and the support rods (406) abutting the bottom of the air inlet valve (401), and the support rods (406) abutting the bottom of the air inlet valve (401), and the support rods (406) abutting the bottom of the air inlet valve (404 ... The bottom end is fixed to the base frame (405), the top end of the support rod (406) is fixed to the sealing ring (407), and the outside of the sealing ring (407) abuts against the junction of the venturi tube (403) and the throat tube; and the exhaust assembly (500), which includes an exhaust valve (501) connected to the exhaust port of the cylinder block (201); the composite filter element (404) is shaped as a frustocone matching the inner cavity of the venturi tube (403), and the composite filter element (404) includes a meltblown cloth filter element (404). 1) and activated carbon filter paper filter element (4042), wherein the activated carbon filter paper filter element (4042) covers the outside of the meltblown cloth filter element (4041), the top port of the activated carbon filter paper filter element (4042) is covered by the bottom of the sealing ring (407), and the inner hole of the sealing ring (407) is aligned with the top of the meltblown cloth filter element (4041); the support rod (406) and the base frame (405) together form a rigid support structure, which is used to support the composite filter element (404) under the impact of airflow to prevent it from deforming.

2. The negative pressure vacuum pump of claim 1, wherein: The support assembly (100) also includes protective covers (102) fixed to both sides of the bracket (101) and casters (103) fixed to the bottom of the bracket (101).

3. The negative pressure vacuum pump of claim 2, wherein: The pump body (200) also includes a piston rod (203) fixed to the center of the piston ring (202) and a guide frame (204) sliding outside the piston rod (203), the guide frame (204) being fixed to the bottom port of the cylinder body (201); the piston rod (203) is driven by a drive source (300).

4. The negative pressure vacuum pump of claim 3, wherein: The drive source (300) includes a motor (301) fixed on a bracket (101), a crank (302) fixed on the drive shaft of the motor (301), and a connecting rod (303) rotating on the crank (302), with one end of the connecting rod (303) away from the crank (302) rotatably connected to the bottom end of the piston rod (203).

5. The negative pressure vacuum pump of claim 4, wherein: The exhaust assembly (500) also includes an aluminum alloy gas tank (502) connected to the outlet of the exhaust valve (501) and a pressure gauge (503) fixed on the aluminum alloy gas tank (502), which is fixedly installed inside the bracket (101).

6. The negative pressure vacuum pump as described in claim 5, characterized in that: Both the intake valve (401) and the exhaust valve (501) are one-way valves.

7. The negative pressure vacuum pump as described in claim 6, characterized in that: Both the outer tube (402) and the venturi tube (403) are made of transparent material.

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