CN206361156U - A kind of vapour-pressure type acceleration switching valve - Google Patents

Abstract

The utility model is related to a kind of vapour-pressure type acceleration switching valve, including valve body and source of the gas two large divisions, and wherein valve body is made up of shell, central shaft, cylinder, front and rear seal assembly, ozzle etc., and source of the gas is made up of seal gas tank and its attached valve, pipeline etc..When the two-position four-way valve for controlling source of the gas flow direction is in off-position, the front side inflation rear side of cylinder is deflated, and two groups of seal assemblies before and after cylinder-pressing, valve is closed；Conversely, when controlling two-position four-way valve powered, the rear side inflation front side of cylinder is deflated, and valve is opened.The utility model is mainly used in sub- transonic and supersonic wind tunnel, uses valve opening or shut-in time to be not more than 1s as quick valve；Annual open and close number of times 1.5 ten thousand times, 1 year time between overhauls(TBO), service life 10 years.

Description

A pneumatic quick switch valve

technical field

The utility model relates to a pneumatic quick switch valve, in particular to a wind tunnel compressed air control switch valve, which belongs to the field of valves.

Background technique

The sub-span super wind tunnel is a high-speed wind tunnel with a speed range of Mach number 0.4<M≤4.5. The typical sub-span super wind tunnel structure consists of air source, main valve, fast valve, pressure regulating valve, front chamber, nozzle, test Sections, outlets, etc., as shown in Figure 6. During the test, the compressed air in the air source passes through the main valve→fast valve→pressure regulating valve and then enters the front chamber for rectification, the speed is adjusted by the nozzle, and it is discharged from the outlet after the test in the test section. In addition, some wind tunnels integrate the functions of the fast valve and the pressure regulating valve, and realize the functions of fast opening and closing and pressure regulation by a fast pressure regulating valve. Since its content has nothing to do with the utility model, it will not be repeated here.

Along the airflow direction, the valves that isolate the air source from the wind tunnel are the main valve, quick valve and pressure regulating valve. The function of the main valve is to close the air source to prevent gas leakage in the air source. It is characterized by good sealing performance, slow switching speed, and few switching times. Generally, ball valves, globe valves or butterfly valves with good sealing performance are used as the main valve. It is closed during holiday shutdown and wind tunnel maintenance, and is always open during the daily test and preparation process of the wind tunnel; the function of the pressure regulating valve is to adjust the opening to adjust the pressure in the front chamber and in front of the nozzle to be relatively stable at all times, so that The air velocity and flow field are stable, and the general structural forms are butterfly plate type, cone barrel type, slit type, etc., which are characterized by poor sealing performance or no sealing effect, and are only used for opening adjustment; the role of the fast valve is in the test It opens quickly at the beginning and closes quickly at the end of the test. It is always closed during the daily production test of the wind tunnel to isolate the air source from the wind tunnel. It is one of the most frequently used equipment for wind tunnel tests. The fast valve is characterized by rapid switching and automatic closing in case of accidental power failure.

With the development of modern advanced wind tunnels towards higher test efficiency and more test times, the annual use frequency of fast valves has far exceeded the limit of the annual switching times that ordinary valves can withstand. Combined with the requirements of the wind tunnel test on the rapid switching, fast closing and repeated switching of the fast valve, this paper proposes a pneumatic fast switching valve to be used as the fast valve in the wind tunnel.

Utility model content

The purpose of this utility model is to overcome the above-mentioned shortcomings of the prior art, and provide a pneumatic fast switching valve, which is used as a fast valve in a sub-transonic wind tunnel, and is suitable for very frequent fast opening and closing conditions.

The above-mentioned purpose of the utility model is achieved through the following technical solutions:

Provide a pneumatic quick switch valve, including valve body, air source and air source control circuit;

The gas source is used to provide the gas required by the valve body switch;

The gas source control circuit is used to switch the flow direction of the gas source gas;

The valve body includes a shell, a front sealing assembly, a rear sealing assembly, a cylinder, and a central shaft;

The shell includes a shell with openings at both ends and an inner central cylinder fixed in the middle of the shell. The bottom of the inner central cylinder has an opening, the opening matches the size of the rear end of the central shaft, and an air passage is provided between the opening and the outer surface of the shell;

The front sealing assembly includes an outer ring and an inner ring, the outer ring matches the upstream opening end of the casing, the inner ring is fixedly connected to the outer ring, the opening of the inner ring matches the front end size of the central shaft, the inner ring has a through hole, and the outer ring There is an air channel communicating with the through hole of the inner ring, and the front faces of the outer ring and the inner ring are used as the inlet of the working medium;

The rear sealing assembly includes a pressure plate, which is fixed and pressed against the opening end of the central cylinder in the casing;

The central shaft is fixed between the inner ring of the front sealing assembly and the opening of the central cylinder in the housing; the middle part of the central shaft is the piston disc, the front end of the central shaft has a first air hole, and the position of the central shaft near the front end of the piston disc has a second air hole, the first air hole It is a hollow gas channel between the second air hole; the first air hole communicates with the through hole of the inner ring of the front sealing assembly; the rear end of the central shaft has a third air hole, and the central shaft has a fourth air hole near the rear end of the piston disc. There is a hollow gas channel between the air hole and the fourth air hole; the third air hole communicates with the opening at the bottom of the casing;

The cylinder includes an outer sleeve and a cylinder inner cylinder. The cylinder inner cylinder is set on the central axis and can move along the central axis. The piston disk of the central axis is used as the piston of the cylinder, and the cylinder inner cylinder is divided into front and rear by the piston disk. Air chamber; when the valve body needs to be closed, the air source control circuit controls the air source gas to enter the first air hole of the central axis through the air channel of the front sealing assembly, enter the front air chamber of the cylinder through the second air hole, and enter the rear air chamber of the cylinder Connected with the atmosphere, the cylinder moves forward, the front end of the outer sleeve presses the outer ring of the front seal assembly, the rear end of the outer sleeve presses the pressure plate of the rear seal assembly, and the outer sleeve of the cylinder forms a sealing structure with the inner center cylinder of the outer shell , the working medium cannot pass through the valve body; when the valve body needs to be opened, the air source control circuit controls the air source gas to enter the third air hole of the central axis through the air passage of the shell, and enter the rear air chamber of the cylinder through the fourth air hole, The front air chamber of the cylinder communicates with the atmosphere, the cylinder moves backward, and the working medium enters the switch valve through the front seal assembly, passes through the gap between the front seal assembly and the rear seal assembly, and between the outer sleeve of the cylinder and the inner center sleeve of the outer shell. The formed gap flows out of the switch valve from the rear open end of the housing shell.

The beneficial effects of the utility model compared with the prior art are:

(1) The pneumatic fast switching valve of the utility model, the main moving parts are adapted to the working condition of repeated opening and closing under the cooperation of oil mist lubrication, the number of opening and closing times per year is 15,000 times, the maintenance period is 1 year, and the service life is 10 years . It has the advantages of high reliability and long service life;

(2) The air pressure type fast switch valve of the present utility model is set to automatically close the valve after power failure, which ensures that the valve can be closed even under unexpected conditions, and has high safety;

(3) For the air pressure type fast switch valve of the present utility model, the sealing air source adopts the most commonly used clean medium pressure air (pressure level 2.5MPa) in wind tunnel tests, and when accidents such as a small amount of leakage of the sealing air occur, the air source will also It can be quickly replenished, and has the advantages of economical and convenient sealing gas source; air pressure is used as the sealing power source of the valve, even if the sealing gas leaks a small amount, it will not pollute the wind tunnel, which reduces the requirements for sealing gas inside the valve body, and has a clean The advantages;

(4) The air pressure type fast switching valve of the utility model adopts air pressure as the sealing power source of the valve, which can meet the requirement that the opening or closing time of the valve is not more than 1 second, and has the advantage of rapid action;

(5) In the pneumatic quick switch valve of the present invention, the buffer device installed inside the cylinder can not only ensure the quick action but also effectively prevent the collision between the cylinder and the piston, and has the advantages of stable and reliable operation;

(6) In the pneumatic quick switch valve of the present utility model, the outer sleeve of the cylinder only bears the radial force of the working medium but not the axial force, thereby greatly reducing the energy required for the switch valve and having low sealing gas pressure requirements The advantages.

(7) The front and rear sealing gaskets of the utility model are basically only subjected to positive pressure, and are tightly wrapped by the compression plate and the shell structurally, eliminating the hidden trouble that the sealing ring is easily blown away by the air flow, and increasing the sealing gasket durability.

Description of drawings

Fig. 1 is the overall composition of the utility model and the schematic diagram of the valve body structure, and the valve is in a closed state;

Figure 2 is a schematic diagram of the valve body structure in the fully open state of the valve;

Figure 3 is a schematic diagram of the flow direction of the airflow at the moment when the valve is opened or closed at the front sealing component, and the solid line part is the front sealing component;

Figure 4 is a schematic diagram of the flow direction of the airflow at the moment when the valve is opened or closed at the position of the rear sealing component, and the solid line part is the rear sealing component;

Fig. 5 is a structural schematic diagram of the cylinder and the central shaft, and the diagram shows the closed state of the valve;

Figure 6 is a schematic diagram of the structural composition of a typical down-blowing temporary sub-span super wind tunnel.

detailed description

The utility model provides a pneumatic fast switching valve, as shown in Figure 1, which includes two parts: a valve body and an air source. Source, Figure 1 shows the closed state of the valve, and Figure 2 shows the open state of the valve. The features of the valve body include the shell (1), the front sealing assembly (2.0), the rear sealing assembly (3.0), the cylinder (4.0), the central shaft (5.0), the rectifying tail cone (6), the nozzle (7, 8) etc.; the characteristics of the air source include two-position four-way valve (W1), lubricator (W2), one-way valve (W3), stop valve (W4), pressure reducing valve (W5), sealed air tank (W6), Safety valve (W7), pressure gauge (W8), oil-gas separator (W9), etc. When the two-position four-way valve (W1) is in the de-energized state, the upstream pipe joint (7) is connected to the sealed air tank (W6), the downstream pipe joint (8) is connected to the atmosphere, and the left side of the cylinder (4.0) has pressure on the right There is no pressure on the side, the cylinder (4.0) presses the front sealing assembly (2.0) and the rear sealing assembly (3.0), and the valve is in a closed state; otherwise, when the two-position four-way valve (W2) is charged, as shown in Figure 2, the cylinder The right side of (4.0) is under pressure and the left side is without pressure, the cylinder (4.0) moves to the right side, the valve is in an open state, and the working medium flows from the left side to the right through the cavity between the outside of the cylinder (4.0) and the casing (1) side. The clean compressed air of the sealed air tank (W6) comes from the compressed air in the wind tunnel, and the piping and connection forms are omitted in the figure.

The feature of the set two-position four-way valve (W2) is to close the valve in the power-off state, thereby ensuring that the valve can be closed quickly even in the event of an accidental power-off failure, ensuring the safety of the wind tunnel test.

The cylinder (4.0) and the central shaft (5.0) together form a cylinder-piston structure, relying on the compressed air in the sealed air tank (W6) to drive the movement of the cylinder (4.0), and compress the front and rear sealing components (2.0, 3.0) to achieve sealing.

As shown in Figure 3, the features of the front sealing assembly (2.0) include fastening bolts (2.1), stop washers (2.2), front compression discs (2.3), and front sealing pads (2.4). The front compression disc (2.3) is a hub-shaped disc with an internal hollow spoke, the front gasket (2.4) is an oil-resistant rubber product with moderate hardness, and the fastening bolt (2.1) compresses the front compression disc (2.3) and the front gasket (2.4), fixed on the housing (1), the stop washer (2.2) prevents the fastening bolt (2.1) from loosening.

As shown in Figure 4, the features of the rear sealing assembly (3.0) include fastening bolts (3.1), stop washers (3.2), rear compression discs (3.3), and rear sealing gaskets (3.4). The rear compression plate (3.3) is a flange-shaped pressure plate with grooves, the rear sealing gasket (3.4) is an oil-resistant rubber product with moderate hardness, and the fastening bolts (3.1) are compressed. Pad (3.4), fixed on the housing (1), the stop washer (3.2) prevents the fastening bolt (3.1) from loosening.

As shown in Figure 5, the cylinder (4.0) includes a front cylinder head, a rear cylinder head and a cylinder barrel; (4.4), compression disc (4.5), seal ring (4.6), front cylinder head (4.7), shaft sleeve (4.8), throttle jackscrew (4.9); rear cylinder head (4.11～4.19) consists of jackscrew (4.11), spring (4.12), steel ball (4.13), fastening bolt (4.14), pressure plate (4.15), sealing ring (4.16), front cylinder head (4.17), shaft sleeve (4.18), throttle top wire (4.19); the cylinder barrel is made up of an outer sleeve (4.21), a cylinder inner barrel (4.22), and a rib (4.23). The cylinder barrel (4.21-4.23) composed of integral casting or welding, and the front sealing gasket (4.10) and the rear sealing gasket (4.20). The features that are not fully expressed in the drawings also include that the connection between the front cylinder head (4.1-4.9) and the rear cylinder head (4.11-4.19) and the cylinder inner tube (4.22) is tightened by bolts (not shown), and the stop washer ( not shown) to prevent the bolt from loosening. The features not fully expressed in the drawings also include the connection between the outer sleeve (4.21) and the housing (1) by means of a flat key, which limits the freedom of the cylinder (4.0) in the rolling direction.

As shown in Figure 1 and Figure 5, the features of the central shaft (5.0) include a front seal cover (5.1) and a front seal ring (5.2), a central shaft rod (5.3) and a seal ring (5.4), a rear seal cover (5.6) and Rear sealing ring (5.5). The central shaft rod (5.3) is a hollow shaft with hollow ends closed by its piston-shaped middle section, the front cavity is sealed by the front sealing cover (5.1) and the front sealing ring (5.2), and the rear cavity is sealed by the rear sealing cover (5.6) and rear sealing ring (5.5) seal. The central shaft rod (5.3) is erected horizontally between the central hole of the casing (1) and the front pressure plate (2.3), and is sealed with the inner wall of the cylinder inner tube (4.22) by a sealing ring (5.4). The cavity is connected with the upstream pipe joint (7) through the internal cavity of the front pressure plate (2.3), and the internal cavity at the rear side is connected with the downstream pipe joint (8) through the internal cavity of the shell (1).

As shown in Figure 1 and Figure 2, since the outer sleeve (4.21) of the cylinder (4.0) only bears the radial force of the working medium and not the axial force, it can greatly reduce the energy required for switching valves and the pressure of the sealing gas. It can be reduced to 2MPa, and the medium-pressure air in the wind tunnel can be used as the source of sealing air.

The flow direction of the working medium in the valve is from left to right. At the moment when the valve is opened or about to close, as shown in Figure 3, the force of the air flow acting on the front gasket (2.4) at this time can be generally regarded as positive pressure. See that the front gasket (2.4) is tightly wrapped by the front compression plate (2.3) and the shell (1), so the front gasket (2.4) is not easy to be blown out by the air flow; similarly, as shown in Figure 4, the rear The gas force of the gasket (3.4) can generally be regarded as positive pressure, and it is tightly wrapped by the rear compression plate (3.3) and the shell (1) structurally, so the rear gasket (3.4) is not easily affected by the airflow. blow out. Simultaneously, the rigidity of the body of the front and rear sealing pads (2.4, 3.4) can be greatly reduced, and the excellent rebound performance of the rubber material can be brought into full play. This structural design improves the service life of the gasket (2.4, 3.4) as a whole.

The two shaft sleeves (4.8, 4.18) at the front and rear of the cylinder (4.0) are made of oil-free lubricating material with brass inlaid with polytetrafluoroethylene, and the kinematic pair between the cylinder (4.0) and the central shaft (5.0) adopts suitable frequent Reciprocating dynamic sealing device: For example, the sealing ring (4.6, 4.16) adopts a V-shaped sealing ring, and the sealing ring (5.4) adopts an O-shaped sealing ring, combined with the oil mist lubrication of the sealing gas, the moving parts can withstand frequent opening closed condition.

The front and rear cylinder heads of the cylinder (4.0) are respectively equipped with buffer devices to make the acceleration and deceleration process of the cylinder (4.0) more stable, and the acceleration process is fast, which is a first-level acceleration buffer; the deceleration process is slow, which is a second-level deceleration buffer. As shown in Figure 5, it shows an example of exhausting the cylinder chamber on the right side and filling the cylinder chamber on the left side. The normal exhaust process of the cylinder chamber on the right side is directly discharged from the upper and lower large holes on the central shaft (5.3) , when the cylinder (4.0) moves to the left to the distance before the end, the large hole on the central shaft (5.3) is blocked, and the gas is forced to flow into the large hole from the small hole on the upper part of the rear cylinder head (4.17), while The small hole in the lower part becomes a one-way valve under the action of the top wire (4.11), spring (4.12), and steel ball (4.13), and the gas cannot flow out, forming a first-level deceleration buffer; when the cylinder (4.0) continues to move to the left, it immediately hits the terminal Before, the airflow of the small holes on the top of the rear cylinder head (4.17) was difficult to form a secondary deceleration buffer from the gap. In the same way, as shown in the illustration, the cylinder chamber on the right is filled with air, and the cylinder chamber on the left is exhausted. The gas in the large hole on the central shaft (5.3) enters from the upper and lower small holes of the rear cylinder head (4.17) at the same time, forming First-level buffer acceleration, when the cylinder head (4.17) moves to the right until the large hole is no longer closed, the gas directly enters the right cylinder chamber from the large hole, forming a normal acceleration. With the buffer device, although the movement speed of the moving parts is fast, the acceleration and deceleration process is stable, which improves the ability of the moving parts to withstand frequent opening and closing conditions.

The utility model uses air pressure as the power source to drive the cylinder in the valve body to drive the outer sleeve to move. When it moves to the front end, the outer sleeve presses the front and rear sealing gaskets to close the valve; when it moves to the rear end, the outer sleeve Separate from the sealing gasket to realize the valve opening. The power source adopts clean medium-pressure air (pressure level 2MPa), which is the most commonly used in wind tunnel tests, and the source is economical and convenient; the components of the air source are commonly purchased parts, which are easy to replace and maintain; After power on, the valve is automatically closed to ensure the safety of the wind tunnel even under unexpected conditions; the gas flow direction in the valve body makes the gasket in a leeward state, preventing damage from repeated blowing of the pipeline gas, and the structure is also conducive to the performance of the seal The good rebound effect of the cushion rubber improves the service life of the gasket; the shaft sleeve of the cylinder is made of oil-free lubricating material based on brass and embedded with PTFE plastic, and the dynamic seal between the cylinder and the shaft adopts a V-shaped seal ring , The dynamic seal of the cylinder and piston adopts O-ring, and the oil mist lubrication of the air source can effectively improve the service life of the piston and cylinder.

The pneumatic quick switch valve of the utility model is mainly used as a quick valve in a sub-transonic wind tunnel, and is suitable for very frequent quick opening and closing working conditions. The specific scope of application is: the air source is clean compressed air, and the pressure level is 2.5MPa; The nominal diameter of the valve body is DN200～DN2600, the suitable working medium is clean compressed air, the pressure level is 2.5MPa, the opening or closing time of the valve is not more than 1s; the number of opening and closing times per year is 15,000 times; the maintenance period is 1 year, and the service life is 10 years.

The above is only the best specific implementation of the utility model, but the scope of protection of the utility model is not limited thereto, anyone familiar with the technical field can easily think of All changes or replacements should fall within the protection scope of the present utility model.

The content that is not described in detail in the description of the utility model belongs to the known technology of those skilled in the art.

Claims (10)

1. A pneumatic quick switch valve, characterized in that it comprises a valve body, an air source and an air source control circuit; The gas source is used to provide the gas required by the valve body switch; The gas source control circuit is used to switch the flow direction of the gas source gas; The valve body includes a casing (1), a front sealing assembly (2.0), a rear sealing assembly (3.0), a cylinder (4.0), and a central shaft (5.0); The shell (1) consists of a shell with openings at both ends and an inner central cylinder with a fixed middle section inside the shell. The bottom of the inner central cylinder has an opening that matches the size of the rear end of the central axis (5.0), and the distance between the opening and the outer surface of the shell Air passage is set between; The front seal assembly (2.0) includes an outer ring and an inner ring, the outer ring matches the upstream opening end of the housing (1), the inner ring is fixedly connected to the outer ring, and the opening of the inner ring matches the front end size of the central shaft (5.0) , the inner ring has a through hole, the outer ring has an air passage communicating with the through hole of the inner ring, and the front faces of the outer ring and the inner ring are used as the working medium inlet; The rear seal assembly (3.0) includes a pressure plate, which is fixed and pressed against the opening end of the central cylinder in the shell (1); The central shaft (5.0) is fixed between the inner ring of the front seal assembly (2.0) and the opening of the central cylinder in the casing (1); the middle part of the central shaft (5.0) is a piston disc, and the front end of the central shaft (5.0) has a first air hole, and the center The position of the shaft close to the front end of the piston disc has a second air hole, and there is a hollow gas passage between the first air hole and the second air hole; the first air hole communicates with the through hole in the inner ring of the front sealing assembly (2.0); the rear of the central shaft (5.0) There is a third air hole at the end, and a fourth air hole at the position where the central axis is close to the rear end of the piston disc. There is a hollow gas passage between the third air hole and the fourth air hole; the third air hole communicates with the opening at the bottom of the shell (1); The cylinder (4.0) includes an outer sleeve (4.21) and a cylinder inner cylinder (4.22). The cylinder inner cylinder (4.22) is sleeved on the central shaft (5.0) and can move along the central shaft (5.0). The central shaft ( 5.0) as the piston of the cylinder (4.0), the cylinder inner tube (4.22) is divided into front and rear air chambers by the piston disk; when the valve body needs to be closed, the air source control circuit controls the air source gas to pass through the front seal The air passage of the component (2.0) enters the first air hole of the central shaft (5.0), enters the front air chamber of the cylinder through the second air hole, the rear air chamber of the cylinder communicates with the atmosphere, the cylinder (4.0) moves forward, and the outer sleeve (4.21 ) is pressed against the outer ring of the front sealing assembly (2.0), the rear end of the outer sleeve (4.21) is pressed against the pressure plate of the rear sealing assembly (3.0), and the outer sleeve (4.21) of the cylinder (4.0) and the housing (1) The inner central cylinder of the inner cylinder forms a sealed structure, and the working medium cannot pass through the valve body; when the valve body needs to be opened, the air source control circuit controls the air source gas to enter the central axis (5.0) through the air channel of the shell (1). The air hole enters the rear air chamber of the cylinder through the fourth air hole, the front air chamber of the cylinder communicates with the atmosphere, the cylinder (4.0) moves backward, the working medium enters the switch valve through the front sealing assembly (2.0), and passes through the front sealing assembly (2.0) and the gap between the rear seal assembly (3.0), the gap formed between the outer sleeve (4.21) of the cylinder (4.0) and the inner center tube of the casing (1), the switch is flowed out from the rear open end of the casing (1) valve. 2. The pneumatic quick switch valve according to claim 1, characterized in that the front seal assembly (2.0) also includes a front gasket (2.4), the front end of the housing (1) has an annular protrusion, and the front seal The outer ring of the assembly (2.0) presses the front gasket (2.4) to the annular protrusion at the front end of the housing (1) shell. 3. The pneumatic quick switch valve according to claim 1 or 2, characterized in that, the rear sealing assembly (3.0) includes a rear sealing gasket (3.4), and the pressure plate of the rear sealing assembly (3.0) presses the rear sealing gasket (3.4) ) is fixed on the front end of the central cylinder in the housing (1), and the inner diameter of the gasket is smaller than the inner diameter of the central cylinder; The flange at the end presses the rear gasket (3.4). 4. The pneumatic quick switch valve according to claim 1 or 2, characterized in that it also includes a rectifying tail cone (6), which is arranged at the rear end of the center cylinder bottom of the shell (1) to guide the working medium to the shell (1) The rear open end of the shell. 5. The pneumatic quick switch valve according to claim 1 or 2, characterized in that it also includes an upstream pipe joint (7) and a downstream pipe joint (8), the upstream pipe joint (7) is connected to the front sealing assembly (2.0 ) the inlet end of the air passage between the outer ring and the inner ring; the downstream pipe joint (8) is connected to the outlet end of the air passage of the shell (1). 6. The pneumatic quick switch valve as claimed in claim 5, characterized in that, the air source control circuit comprises a two-position four-way valve (W1) and a sealed air tank (W6), and the two-position four-way valve (W1) When the power is off, the upstream pipe joint (7) is connected to the sealed air tank (W6), the downstream pipe joint (8) is connected to the atmosphere, and the valve body is in a closed state; when the control two-position four-way valve (W2) is electrified, The upstream pipe joint (7) is connected to the atmosphere, the downstream pipe joint (8) is connected to the sealed air tank (W6), and the valve body is opened. 7. The pneumatic quick switching valve as claimed in claim 6, characterized in that the clean compressed air of the sealed air tank (W6) comes from the compressed air in the wind tunnel. 8. The pneumatic quick switching valve as claimed in claim 1 or 2, wherein the cylinder (4.0) comprises a front cylinder head, a rear cylinder head and a cylinder barrel; The front cylinder head assembly includes a first jacking wire (4.1), a first spring (4.2), a first steel ball (4.3), a first pressure disc (4.5), a front sealing ring (4.6), a front cylinder head (4.7 ), shaft sleeve (4.8), first throttle screw (4.9); the rear section of the front cylinder head (4.7) is set on the front section of the central shaft (5.0) through the shaft sleeve (4.8), and the front section of the front cylinder head (4.7) A front sealing ring (4.6) is set between the central shaft (5.0), and is pressed by the first pressure disc (4.5); the front cylinder head (4.7) has a first vertical hole, and a second vertical hole is set in the first vertical hole. A jacking wire (4.1), a first spring (4.2) and a first steel ball (4.3), the first jacking wire (4.1) pre-presses the first steel ball (4.3) in the first vertical hole through the first spring (4.2) Inside, there is a first horizontal through hole on the side wall where the first vertical through hole steel ball is located; the first shaft sleeve (4.8) is provided with a second vertical through hole corresponding to the position of the first vertical through hole; , the second vertical hole of the first shaft sleeve (4.8) is facing the second air hole, the gas source gas enters the first vertical hole through the first air hole, the second air hole, and the second vertical hole, and presses the steel ball (4.3) Go to the top wire (4.1), open the first horizontal through hole, and the gas enters the front air chamber through the first horizontal through hole; when the cylinder moves to the position where the second vertical through hole and the second air hole are staggered, the steel ball (4.3) rebounds, Reclose the first horizontal through hole; the front cylinder head (4.7) also has a third vertical through hole, and the first throttle jackscrew (4.9) is arranged in the third vertical through hole, and the first throttle jackscrew (4.9) is a cone shape, adjust the length of the first throttling top wire (4.9) inserted into the third vertical hole, and can change the airway opening in the third vertical hole; the side wall of the third vertical hole has a second horizontal hole , so that the third vertical hole communicates with the front air chamber. When the cylinder is located at the rearmost end, the central axis piston disk closes the second horizontal hole; the first bushing (4.8) is provided with a fourth vertical hole corresponding to the position of the third vertical hole When the cylinder is at the rear end, the fourth vertical hole of the first bushing (4.8) is facing the second air hole; after the current air chamber is inhaled, the cylinder moves forward, and the central axis piston disc no longer closes the second horizontal hole. The air source gas enters the front air chamber through the gas channel between the first air hole and the second air hole, the fourth vertical hole, the third vertical hole, and the second horizontal hole; when the first shaft sleeve (4.8) After the four vertical through holes are staggered from the second air hole, the gas no longer enters the fourth vertical through hole; when exhausting, the cylinder moves backward, and when the fourth vertical through hole of the first bushing (4.8) is opposite to the second air hole, The gas enters the second horizontal through hole through the front air chamber, then enters the second air hole through the third vertical through hole and the fourth vertical through hole, and exhausts through the first air hole; The rear cylinder head has the same structure as the front cylinder head assembly, and is set on the rear section of the central axis (5.0); The cylinder barrel includes an outer sleeve (4.21), a cylinder inner barrel (4.22) and ribs (4.23); the ribs (4.23) are used to fix the outer sleeve (4.21) and the cylinder inner barrel (4.22) connect. 9. The pneumatic quick switch valve according to claim 1 or 2, characterized in that, the central shaft (5.0) includes a front sealing cover (5.1), a front sealing ring (5.2), a central shaft rod (5.3) and a sealing Ring (5.4), rear sealing cover (5.6) and rear sealing ring (5.5); The middle part of the central shaft (5.3) is a piston disc, the front end of the central shaft (5.3) has a first air hole, the front end of the piston disc has a second air hole, and a hollow gas passage is between the first air hole and the second air hole; the central shaft ( 5.3) There is a third air hole at the rear end, and a fourth air hole at the rear end of the piston disc. There is a hollow gas passage between the third air hole and the fourth air hole; the front sealing cover (5.1) presses the front sealing ring (5.2) to the central axis The front end of the rod (5.3); the rear sealing cover (5.6) compresses the rear sealing ring (5.5) to the rear end of the central shaft rod (5.3). 10. The pneumatic quick switch valve according to claim 1 or 2, characterized in that the working medium and gas source are both clean gas, and the pressure level is 2.5MPa.