A linkage-type medical negative pressure generator

Abstract

This invention discloses a linkage-type medical negative pressure generator, comprising a valve body and a slide valve. The slide valve includes a piston forming a large end and a piston rod forming a small end. A central hole is formed inside the slide valve, and an open port is formed at the large end of the piston. An air inlet and an air outlet communicating with the central hole are respectively provided on the piston rod. The slide valve is movably installed in the valve body, forming a differential piston-driven switching structure, and a control port is formed outside the large port of the piston. The open state of the control port is linked with the pressure on both sides of the piston, thereby actuating the slide valve. The linkage-type medical negative pressure generator provided by this invention achieves linkage control, is easy to use, improves work efficiency, and saves driving air source. Single-channel control simplifies the control method and facilitates the setting of control switches on the host device's negative pressure suction device.

Description

Technical Field

[0001] This invention relates to negative pressure suction technology, and more specifically to a medical negative pressure generator. Background Technology

[0002] In the field of medical negative pressure suction surgery, negative pressure is used as the driving force for surgical suction to remove waste fluids during surgery. There are typically two types of negative pressure sources for negative pressure suction: one is a tubular negative pressure source provided by a medical central suction system; the other, when a tubular negative pressure source is unavailable, is a negative pressure source generated by a negative pressure generator using compressed gas. The negative pressure source is connected to the negative pressure suction device, which then performs the negative pressure suction surgery.

[0003] Compressed gas driven negative pressure generators are generally gas jet pump type negative pressure generators, which are simple in structure, low in cost, and easy to use and maintain. The suction inlet of the negative pressure generator is connected to the negative pressure suction device. When in use, the driving gas source of the negative pressure generator must be turned on first. After the negative pressure generator starts working, it provides a negative pressure source for the negative pressure suction device, which can then operate. Similarly, when stopping use, the driving gas source of the negative pressure generator must be turned off to stop the negative pressure generator from working; otherwise, the driving gas source will be wasted.

[0004] Therefore, existing compressed gas-driven negative pressure generators require manual switching of the driving gas source during use; otherwise, the generator will either not work or remain continuously on, wasting driving compressed gas. This is inconvenient to use, as it's easy to forget to turn off the driving gas source, resulting in waste. Summary of the Invention

[0005] Existing compressed gas-driven negative pressure generator solutions require manual switching of the generator's driving gas source, which is inconvenient and wasteful of driving compressed gas. The purpose of this invention is to provide a remotely controlled, interconnected medical negative pressure generator that can link the generator with the host's negative pressure suction device. This design is convenient to operate, improves work efficiency, saves driving gas, and effectively overcomes the problems of existing technologies.

[0006] To achieve the above objectives, the present invention provides a linkage-type medical negative pressure generator, comprising a valve body and a slide valve. The slide valve includes a piston forming a large end and a piston rod forming a small end. A central hole is formed inside the slide valve, and an open port is formed at the large end of the piston. An air inlet and an air outlet communicating with the central hole are provided at corresponding positions on the piston rod. The slide valve is movably disposed in the valve body, forming a differential piston-driven switching structure, and a control port is formed outside the large port of the piston. The open state of the control port is linked with the pressure in the large cavity outside the piston, thereby actuating the slide valve to open or close.

[0007] Furthermore, a throttling unit is provided inside the slide valve, and the throttling unit connects the central hole inside the slide valve and both sides of the piston.

[0008] Furthermore, the throttling unit is a throttle or a micro-leakage flow limiting valve.

[0009] Furthermore, the valve body is provided with a switch cavity extending along a first direction. One end of the switch cavity is a piston cavity that mates with the large end of the slide valve, and the other end is a slide valve cavity that mates with the small end of the slide valve. The slide valve cavity is provided with an air inlet cavity and an air outlet cavity. An air inlet is provided on the side of the air inlet cavity. The valve body is provided with a jet pump cavity arranged along a second direction.

[0010] Furthermore, when the slide valve is placed in the switching cavity, the piston chamber of the switching cavity is divided into a large piston chamber located outside the piston and a piston rod chamber located inside the piston. The large piston chamber is connected to the control port, and the piston rod chamber is connected to the intake chamber.

[0011] Furthermore, when the control port of the negative pressure generator is opened, the piston large chamber is connected to the atmosphere, and the pressure is atmospheric pressure. The piston rod chamber is the driving air source pressure, which generates a pressure difference on both sides of the piston, driving the slide valve to move in the first direction, opening the driving air source of the negative pressure generator, and the negative pressure generator works; the throttling unit controls the discharge flow rate.

[0012] When the control port is blocked, air pressure is supplied to the piston large chamber through the throttling unit. When the pressure in the piston large chamber increases, the force of the piston large chamber is greater than the force of the piston rod chamber, and finally the piston differential is formed, which drives the slide valve to move in the second direction, closes the slide valve, cuts off the driving air source, and shuts off the negative pressure generator.

[0013] Furthermore, the negative pressure generator may also include a handle, which is driven and connected to a slide valve.

[0014] The linkage-type medical negative pressure generator provided by this invention features automatic on / off switching, making it convenient to use, improving work efficiency, and saving on driving gas supply. Single-channel control simplifies the control method and facilitates the setting of control switches for the host device's negative pressure suction unit.

[0015] The linkage-type medical negative pressure generator provided by this invention adopts a differential piston driven slide valve structure and single-channel (pipeline) control, which simplifies the host device control method, facilitates the setting of control switches for the host device negative pressure suction device, and realizes linkage between the negative pressure generator and the host negative pressure suction device. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0017] Figure 1 A structural example diagram of the linkage-type medical negative pressure generator provided by the present invention;

[0018] Figure 2 A schematic diagram illustrating the principle of the linkage-type medical negative pressure generator provided by the present invention;

[0019] Figure 3 This is a structural example diagram of the linkage-type medical negative pressure generator in Example 1 of the present invention.

[0020] Figure 4 This is a structural example diagram of the valve body in Example 1 of the present invention;

[0021] Figure 5 This is an example diagram of the stopped working state of the linkage-type medical negative pressure generator in Example 1 of the present invention;

[0022] Figure 6 This is a schematic diagram of the working principle of the linkage medical negative pressure generator in the off state in Example 1 of the present invention;

[0023] Figure 7 This is an example diagram of the working state of the linkage-type medical negative pressure generator in Example 1 of the present invention;

[0024] Figure 8 This is a schematic diagram of the working principle of the linkage medical negative pressure generator in Example 1 of the present invention.

[0025] Figure 9 This is an example diagram of the unidirectional throttling scheme in Example 2 of the present invention;

[0026] Figure 10 This is an example diagram of the dual-control scheme of automatic and manual control in Example 3 of the present invention. Detailed Implementation

[0027] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0028] See Figure 1 and Figure 2 This invention addresses the problem of negative pressure generators requiring manual switching of the driving air source. It provides a linkage-type negative pressure generator, comprising a valve body 1, a slide valve 2, and a jet pump 5. The valve body 1 can be connected to an external driving air source. The jet pump 5 is housed within the valve body 1. The slide valve 2 is correspondingly located within the valve body 1, forming a switching structure based on a differential piston-driven two-position two-way slide valve. A single-channel pipeline control method is used to control the connection between the external driving air source connected to the valve body 1 and the jet pump 5.

[0029] Specifically, the slide valve 2 in this solution includes a piston 2-1 forming the large end and a piston rod 2-2 forming the small end. A central hole 2-3 is formed inside the slide valve, and an open port is formed at the large end of the piston.

[0030] Furthermore, this design includes a throttling unit inside the piston 2-1, forming a throttling orifice that connects to the central hole 2-3 inside the slide valve.

[0031] Furthermore, this solution provides an air inlet 2-21 and an air outlet 2-22 at the corresponding position of the piston rod 2-2, which are connected to the central hole. The air inlet 2-21 can be connected to an external driving air source of the valve body 1, while the air outlet 2-22 can be connected to the jet pump 5.

[0032] The slide valve 2 with this structure is movably installed in the valve body, which can form a switching structure of a two-position two-way slide valve driven by a differential piston. A control port 4-1 is formed outside the large port of the piston. By controlling the opening state of the control port, the pressure of the large chamber outside the piston can be controlled, thereby pushing the slide valve and thus controlling the connection between the drive air source connected to the valve body 1 and the jet pump 5.

[0033] Specifically, in combination Figure 1 and Figure 2 In the linkage negative pressure generator provided by this solution, the piston diameter is D and the piston rod diameter is d. The slide valve is driven by the pressure difference on both sides of the piston, and the differential piston adopts an internal circuit to set a throttling orifice.

[0034] Thus, when control port 4-1 is opened, this linkage negative pressure generator throttles the flow through the throttling orifice, discharging a small amount of gas. The piston's large chamber is connected to the atmosphere at atmospheric pressure Pa, while the piston rod chamber is at the driving gas source pressure P. This creates a pressure difference across the piston, and the force acting on the piston is:

[0035] F1=Pπ(D 2 -d 2 ) / 4;

[0036] Move the drive valve in the first direction (for example, move it to the left in the position shown in the figure) to turn on the negative pressure generator drive air source, and the negative pressure generator will work.

[0037] When the control port is blocked, the throttle orifice slowly replenishes air pressure to the piston's large chamber. As the pressure in the piston's large chamber increases, the force acting in the piston's large chamber becomes greater than the force acting in the piston rod chamber, ultimately creating piston differential. The force acting on the piston is approximately:

[0038] F2=Pπ(D 2 -(D 2 -d 2 )) / 4=Pπd 2 / 4;

[0039] Move the drive valve to the second direction (for example, move it to the right as shown in the diagram), close the drive valve, cut off the drive air source, and shut down the negative pressure generator.

[0040] This enables automatic remote control of the negative pressure generator's on / off state via air pressure transmission. Single-channel (pipeline) control simplifies the host equipment's control method, allowing the negative pressure generator's on / off state to be linked with the host equipment's negative pressure suction device.

[0041] The following specific examples further illustrate the linkage negative pressure generator provided by the present invention.

[0042] Example 1

[0043] See Figure 3 The linkage negative pressure generator given in this example mainly includes a negative pressure generator valve body 1, a slide valve 2, a throttle 3, a cylinder head 4, a jet pump 5, and several sealing rings 6.

[0044] See Figure 4 In this example, the valve body 1 is a block with an internal cavity. The upper part of the valve body 1 is a horizontally penetrating switch cavity 1-1. One end of the switch cavity has a larger diameter and is a piston cavity 1-11, which is used to cooperate with the piston 2-1 in the slide valve 2. The other end of the switch cavity has a smaller diameter and is a slide valve cavity 1-12, which is used to cooperate with the piston rod 2-2 in the slide valve 2.

[0045] Furthermore, the slide valve chamber 1-12 is further provided with an air inlet chamber 1-13 and an air outlet chamber 1-14. Among them, the air inlet chamber 1-13 is closer to the piston chamber 1-11. Each chamber is provided with a sealing ring groove for placing the corresponding sealing ring 6, so as to form an independent cavity for sealing and isolation when the slide valve 2 is in action.

[0046] Furthermore, in this example, an air inlet 1-15 is provided on the side of the air inlet chamber 1-13 for connecting an external driving air source.

[0047] This example also features a vertically open jet pump chamber 1-2 at the lower part of the valve body 1. The upper part of the jet pump chamber 1-2 communicates with the air outlet chamber 1-14; the middle side of the jet pump chamber 1-2 is provided with an air intake (i.e., a negative pressure port) 1-3.

[0048] Regarding the valve body 1 structure described above, the slide valve 2 in this example is a double-section cylinder with a piston 2-1 at the large end and a piston rod 2-2 at the small end. At the same time, a corresponding central hole 2-3 is formed inside the slide valve 2, which forms an open port at the large end of the piston.

[0049] Furthermore, in this example, a double row of radial small through holes communicating with the central hole 2-3 is provided at the corresponding position of the piston rod 2-2. The one on the side of the piston 2-1 is the air inlet hole 2-21, and the other row is the air outlet hole 2-22.

[0050] Furthermore, a sealing ring groove is provided on the piston 2-1 for accommodating the corresponding sealing ring 6.

[0051] In this example, the throttle 3 is installed in the piston 2-1 of the slide valve 2 as a corresponding throttling unit, forming a corresponding throttling orifice that connects to the central hole inside the slide valve. As an example, the throttle 3 in this example is a common screw plug type throttle with a small through hole in the center.

[0052] In this example, the cylinder head 4 is a screw cap with a central through hole, which is installed in the switch cavity 1-1 on the upper part of the valve body 1. Its central hole serves as the control port 4-1 for communication with the host device.

[0053] In this example, the jet pump 5 is housed in the jet pump chamber 1-2 on the valve body 1. As an example, the jet pump 5 in this example is preferably a gas-driven jet pump, including a nozzle 5-1, a diffuser 5-2, an intake port 5-3, and an exhaust port 5-4.

[0054] In this example, the sealing ring 6 serves as a sealing component, used to be positioned at the corresponding isolation location to form a dynamic sealing structure. This example employs four sets of sealing rings 6: a first sealing ring 6-1, a second sealing ring 6-2, a third sealing ring 6-3, and a fourth sealing ring 6-4.

[0055] The first sealing ring 6-1 is disposed in the sealing ring groove on the piston 2-1. When the slide valve 2 is placed in the switch cavity 1-1 on the upper part of the valve body 1, it cooperates with the inner wall of the piston cavity 1-11 to seal and divide the piston cavity 1-11 to form the piston large cavity 4-2 and the piston rod cavity 2-10.

[0056] The second sealing ring 6-2, the third sealing ring 6-3, and the fourth sealing ring 6-4 are sequentially arranged in the sealing ring groove within the switch cavity 1-1 to cooperate with the piston rod 2-2 on the slide valve 2. The second sealing ring 6-2 corresponds to the air inlet hole 2-21 on the piston rod 2-2, the third sealing ring 6-3 corresponds to the air outlet hole 2-22 on the piston rod 2-2, and the fourth sealing ring 6-4 corresponds to the end of the piston rod 2-2, thus forming a sealed isolation between the air inlet chamber 1-13 and the air outlet chamber 1-14 within the switch cavity 1-1. Simultaneously, the air inlet hole 2-21 on the piston rod 2-2 communicates and cooperates only with the air inlet chamber 1-13 within the switch cavity 1-1; and the third sealing ring 6-3 is located at the air outlet hole 2-22. During the stroke of piston rod 2-2 within switch cavity 1-1, when vent hole 2-22 moves with piston rod 2-2 within switch cavity 1-1, it can move between the second sealing ring 6-2 and the third sealing ring 6-3. At this time, vent hole 2-22 is connected and engaged with vent chamber 1-14. Furthermore, when vent hole 2-22 moves with piston rod 2-2 within switch cavity 1-1, it can also move between the third sealing ring 6-3 and the fourth sealing ring 6-4. At this time, vent hole 2-22 is sealed and isolated by the third sealing ring 6-3 and the fourth sealing ring 6-4, and vent chamber 1-14 is simultaneously sealed and isolated by the second sealing ring 6-2 and the third sealing ring 6-3, thus disconnecting the connection between vent hole 2-22 and vent chamber 1-14.

[0057] Based on this, the linkage negative pressure generator in this example is assembled and set up (in conjunction with...). Figure 3-4 Insert the slide valve 2 into the horizontally penetrating switch cavity 1-1 in the upper part of the valve body 1; place the throttle 3 at the open end of the center hole 2-3 of the slide valve 2 to seal the outlet of the center hole 2-3.

[0058] The cylinder head 4 further seals the outer opening of the large piston chamber 1-11 of the valve body 1; the outer end of the piston rod 2-2 is open to the atmosphere. The jet pump 5 is placed inside the jet pump chamber (1-2).

[0059] like Figure 5 As shown, the slide valve 2, configured in this way, divides the piston chamber 1-11 of the switching cavity 1-1 through the first sealing ring 6-1 located outside the piston 2-1:

[0060] A large piston chamber 4-2 is formed between the outer side of the piston 2-1 and the cylinder head 4, and this large piston chamber 4-2 communicates with the control port 4-1;

[0061] A piston rod cavity 2-10 is formed inside the piston 2-1, and the piston rod cavity 2-10 communicates with the intake cavity 1-13.

[0062] Furthermore, the driving air source is connected from the air inlet 1-15, entering the air inlet chamber 1-13 and the piston rod chamber 2-10. It enters the central hole 2-3 of the slide valve 2 through the small air inlet hole 2-21 in the piston rod 2-2, and then enters the large piston chamber 4-2 at the outer end of the piston 2-1 through the throttling hole 3, and is introduced into the control port 4-1. The control port 4-1 is connected to the switch of the external host negative pressure suction device.

[0063] The operating status of the linkage negative pressure generator based on this is as follows:

[0064] See Figure 5-6 When the external host negative pressure suction device is turned off, the control port 4-1 on this linkage negative pressure generator is in the closed state. The driving air pressure P slowly replenishes the air pressure to the piston large chamber 4-2 through the throttle 3 until the pressure difference on both sides of the piston 2-1 is close to zero.

[0065] At this time, since the pressure-bearing areas of the piston large chamber 4-2 and the piston rod chamber 2-10 are different, when the force of the piston large chamber 4-2 is greater than the force of the piston rod chamber 2-10, a differential piston is formed.

[0066] The force acting on slide valve 2 is to the right, and its magnitude is approximately:

[0067] F2=Pπ(D 2 -(D 2 -d 2 )) / 4=Pπd 2 / 4 (e.g.) Figure 1 and Figure 2 (As shown).

[0068] The force generated in this way drives the slide valve 2 to move to the right, while simultaneously replenishing the gas in the piston chamber 4-2 through the throttle 3. The small outlet hole 2-22 on the piston rod 2-2 is moved out of the outlet chamber 1-14 and located between the third sealing ring 6-3 and the fourth sealing ring 6-4. At this time, the small outlet hole 2-22 is sealed and isolated by the third sealing ring 6-3 and the fourth sealing ring 6-4, and the driving gas source cannot enter the outlet chamber 1-14. The slide valve 2 is closed, which in turn shuts off the driving gas source of the jet pump 5. The jet pump 5 does not work, does not generate negative pressure, and the negative pressure generator does not work.

[0069] See Figure 7-8 When the external host negative pressure suction device is turned on, the control port 4-1 on this linkage negative pressure generator is vented, the outer piston chamber 4-2 of piston 2-1 is connected to the atmosphere, and the pressure is atmospheric pressure. A small airflow passes through the throttle 3, the pressure in the piston rod chamber 2-10 is the intake pressure, and the slide valve 2 is subjected to a force to the left, the magnitude of which is:

[0070] F1=Pπ(D 2 -d 2 ) / 4 (e.g.) Figure 1and Figure 2 (As shown).

[0071] The force generated in this way will drive the slide valve 2 to move to the left, and the small air outlet 2-22 will enter the air outlet chamber 1-14 and connect with it; the slide valve 2-2 is opened, and the driving air source passes through the small air inlet 2-21, the center hole 2-3 of the slide valve 2, the small air outlet 2-22, the air outlet chamber 1-14 in sequence, and enters the nozzle 5-1, driving the jet pump 5 to generate negative pressure at the air inlet 1-3. The negative pressure generator works and exhausts from the exhaust port 5-4.

[0072] This allows the negative pressure generator to automatically turn on when the host device is turned on and automatically turn off when the host device is turned off, achieving the purpose of linkage switching of the negative pressure generator. This makes operation convenient, improves work efficiency, and saves on driving gas supply.

[0073] This example demonstrates a remotely controlled, linkage-type negative pressure generator employing a two-position, two-way differential piston-driven slide valve switching structure. In practical applications, when the host equipment's negative pressure suction device is activated, the negative pressure generator is automatically activated via remote control, providing a negative pressure source for the suction device. When the host equipment's negative pressure suction device is deactivated, the negative pressure generator is automatically deactivated via remote control. This eliminates the need for manual activation and deactivation of the negative pressure generator beforehand and afterward, replacing it with a pneumatic-controlled linkage system. It eliminates the need for manual operation of the negative pressure generator, making it convenient to use, highly efficient, and reducing human error.

[0074] Example 2

[0075] This example is based on Example 1, but replaces the throttle 3 in Example 1 with a micro-leakage flow limiting valve 7, while other components remain unchanged.

[0076] See Figure 9 The micro-leakage flow limiting valve 7 used in this example is mainly composed of a return spring 7-1, a valve seat 7-2, and a valve core 7-3. The valve core 7-3 is placed in the valve seat 7-2 through the return spring 7-1.

[0077] When the micro-leakage flow limiting valve 7 with this structure is installed in the slide valve 2, the flow rate increases instantaneously when the control port is vented. The valve core 7-3 is drawn in, overcoming the elastic force generated by the return spring 7-1, and the valve core closes, with only a slight leakage, functioning the same as the throttling orifice. When the control port is closed, the leakage through the micro-leakage flow limiting valve replenishes air pressure to the piston's large chamber. After the piston's large chamber rises slightly, the valve core 7-3 opens under the action of the return spring 7-1, quickly replenishing air pressure to the piston's large chamber, increasing the differential piston's movement speed, and improving the response speed when the slide valve closes.

[0078] Example 3

[0079] This example presents a linkage negative pressure generator scheme based on the schemes in Example 1 or Example 2.

[0080] See Figure 10 This example, based on the linkage negative pressure generator scheme given in Example 1 or Example 2, further introduces a handle 8 for manual control of the slide valve 2.

[0081] Specifically, in this example, the handle 8 is a handle 8 with a needle valve 8-1, and the needle valve 8-1 on the handle 8 is inserted into the slide valve 2 from the front.

[0082] By adding a handle with a needle valve to the slide valve, the needle valve can be opened and closed by rotating the handle.

[0083] In this example, the linkage-type negative pressure generator operates in a remote automatic control mode when the needle valve is opened. When the handle is closed, the needle valve closes, the driving air source pressure of the control port is shut off, and the remote automatic control is ineffective. The manual operation mode can be switched by pushing or pulling the handle to open and close the slide valve.

[0084] Finally, it should be noted that the solutions provided by this invention are not limited to the above-described embodiments, but can be modified and varied in various ways according to design needs and other factors, such as the form and position of the sealing ring, the form and position of the air inlet and outlet, the size ratio of the piston and piston rod, the form of the throttle orifice, and changes in the related structural arrangement, direction and relative position, etc.

[0085] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A linkage-type medical negative pressure generator, including a valve body, characterized in that, It also includes a slide valve, which comprises a piston forming a large end and a piston rod forming a small end. A central hole is formed inside the slide valve, and an open port is formed at the large end of the piston. An inlet and an outlet port communicating with the central hole are provided at corresponding positions on the piston rod. The slide valve is movably mounted in the valve body, forming a differential piston-driven switching structure, and a control port is formed outside the large port of the piston. The open state of the control port is linked to the pressure outside the piston, thereby actuating the slide valve. When the control port is open, the large chamber of the piston is connected to the atmosphere at atmospheric pressure, and the piston rod chamber is the driving air source pressure, creating a pressure difference on both sides of the piston. This drives the slide valve to move in the first direction, activating the driving air source of the negative pressure generator, and the negative pressure generator operates. A throttling unit controls the discharge flow rate. When the control port is blocked, air pressure is supplied to the piston large chamber through the throttling unit. When the pressure in the piston large chamber increases, the force of the piston large chamber is greater than the force of the piston rod chamber, and finally the piston differential is formed, which drives the slide valve to move in the second direction, closes the slide valve, cuts off the driving air source, and shuts off the negative pressure generator.

2. The linkage-type medical negative pressure generator according to claim 1, characterized in that, The slide valve piston is provided with a throttling unit, which connects the central hole inside the slide valve and both sides of the piston.

3. The linkage-type medical negative pressure generator according to claim 2, characterized in that, The throttling unit is a throttle or a micro-leakage flow limiting valve.

4. The linkage-type medical negative pressure generator according to claim 2, characterized in that, The valve body is provided with a switch cavity that extends through a first direction. One end of the switch cavity is a piston cavity that mates with the large end of the slide valve, and the other end is a slide valve cavity that mates with the small end of the slide valve. The slide valve cavity is provided with an air inlet cavity and an air outlet cavity. An air inlet is provided on the side of the air inlet cavity. The valve body is provided with a jet pump cavity that extends along a second direction.

5. The linkage-type medical negative pressure generator according to claim 4, characterized in that, When the slide valve is placed in the switching cavity, the piston chamber of the switching cavity is divided into a large piston chamber located on the outside of the piston and a piston rod chamber located on the inside of the piston. The large piston chamber is connected to the control port, and the piston rod chamber is connected to the intake chamber.

6. The linkage-type medical negative pressure generator according to claim 1, characterized in that, The negative pressure generator also includes a handle, which is driven and connected to a slide valve.

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