A rolling diaphragm structure and Y-type diaphragm valve

Abstract

The utility model discloses a rolling diaphragm structure and a Y-type diaphragm valve, which relate to the technical field of valves for oil and gas sewage pipelines. The rolling diaphragm structure includes a tray and a rolling diaphragm assembled in a sleeve; the rolling diaphragm is in the shape of a top hat and its bottom is fixedly assembled on the sleeve, the tray clamps the top of the rolling diaphragm, the outer wall of the tray extends in the rolling diaphragm cap toward the bottom of the cap, the rolling diaphragm rolls in the sleeve and the rolling diaphragm fits the outer wall of the tray when rolling. By designing the rolling diaphragm structure, the working stroke of the valve movement is independent of the outer diameter of the rolling diaphragm, but is related to the height of the rolling diaphragm, the radius of the inner corner of the rolling diaphragm, the margin and the thickness of the rolling diaphragm, and a valve that meets the working condition requirements can be designed according to the valve structure size requirements. By changing the diaphragm structure, the service life of the valve diaphragm is increased, frequent replacement of the diaphragm is avoided, and maintenance costs are saved; and the valve stroke is not affected by the size of the diaphragm, and the valve can be installed at a specific installation position.

Description

Technical Field

[0001] The utility model relates to the technical field of oil and gas sewage pipeline valves, and more specifically to a rolling diaphragm structure and a Y-type diaphragm valve. Background Art

[0002] The diaphragm valve is a stop valve that uses a diaphragm as a start and stop part to close the flow channel, cut off the fluid, and separate the valve body cavity from the valve cover cavity. The valve seat seal uses a metal valve disc wrapped with non-metallic materials, which has a high load-bearing capacity and sealing performance. The flange seal and valve stem packing seal in the diaphragm seat also serve as a barrier to isolate the valve body and the valve cover, and the seal is reliable. The valve body flow is streamlined, with good flow capacity, small flow resistance, and no dead corners for silting media. The inner cavity of the valve body can be lined with rubber or plastic.

[0003] According to the diaphragm valve design regulations in the Valve Design Manual (4th Edition), traditional diaphragm valves use disc-shaped diaphragms among corrugated diaphragms. Corrugated diaphragms are usually circular diaphragms with concentric rings. Due to the style of the disc-shaped diaphragm, according to the force analysis, the disc-shaped diaphragm is affected by shear force during movement, which causes the diaphragm to fold and bear force every time it moves, resulting in a shortened diaphragm life. Due to the special style of the disc-shaped diaphragm, the movement stroke is related to the diaphragm diameter. The smaller the diaphragm diameter, the shorter the valve stroke, and the larger the diaphragm diameter, the larger the valve stroke. This results in the valve stroke being insufficient in some special installation locations, which can cause the entire pipeline to be unable to fully open. Utility Model Content

[0004] In order to overcome the defects in the above-mentioned prior art, the utility model discloses a rolling diaphragm structure and a Y-type diaphragm valve. The purpose of the utility model is to solve the problem that the valve stroke of the disc-shaped diaphragm in the prior art is related to the diaphragm diameter, resulting in insufficient valve stroke in certain special installation positions, which cannot cause the entire pipeline to be fully opened. The utility model sets a rolling diaphragm structure so that the valve movement working stroke is independent of the rolling diaphragm diameter, and a valve that meets the working condition requirements can be designed according to the valve structure size requirements.

[0005] In order to achieve the above objectives, the technical solution adopted by the utility model is:

[0006] A rolling diaphragm structure comprises a tray and a rolling diaphragm assembled in a sleeve;

[0007] The rolling diaphragm is in the shape of a top hat and its bottom is fixedly mounted on the sleeve, the top of the rolling diaphragm is clamped on the tray, the outer wall of the tray extends in the rolling diaphragm cap toward the bottom of the cap, and the rolling diaphragm rolls in the sleeve and fits with the outer wall of the tray when rolling;

[0008] The rolling width of the rolling diaphragm is:

[0009] ;

[0010] Wherein, X is the rolling width of the rolling diaphragm; is the rolling diaphragm thickness;

[0011] The tray diameter and sleeve diameter meet the following requirements:

[0012] ;

[0013] in, ; ; d is the tray diameter; D is the sleeve diameter;

[0014] The height of the tray and the rolling diaphragm are:

[0015] ;

[0016] ;

[0017] Among them, H t is the tray height; H is the rolling diaphragm height; L is the valve disc stroke; R is the tray corner radius; C is the margin; R m is the inner corner radius of the rolling diaphragm.

[0018] Preferably, the rolling diaphragm is made of rubber sandwiched with silk cloth, a middle hole is provided on the rolling diaphragm, and O-ring edges are provided on the top and bottom of the rolling diaphragm.

[0019] Based on the above rolling diaphragm structure, the utility model also provides a Y-type diaphragm valve, including a valve body, a valve cover, a guide sleeve, a valve stem, a valve disc assembly and a rolling diaphragm structure, wherein the rolling diaphragm structure includes a tray and a rolling diaphragm;

[0020] A three-way Y-shaped tube cavity is arranged in the valve body, and the Y-shaped tube cavity includes a liquid inlet tube cavity, a liquid outlet tube cavity and a valve tube cavity. The valve cover is assembled at the top end of the valve tube cavity, the guide sleeve is assembled inside the valve tube cavity, the valve stem is slidably assembled in the guide sleeve, the bottom end of the valve stem is assembled with a valve flap assembly for closing the liquid inlet tube cavity, and the top end is assembled with a tray. The inner end of the rolling diaphragm is assembled on the tray, and the outer end is assembled between the valve body and the valve cover. The rolling diaphragm divides the cavity into an upper external air source cavity and a lower medium air source cavity.

[0021] Preferably, the internal cavity of the valve cover and the upper cavity of the valve tube cavity form a sleeve. During the closing and / or opening process of the Y-type diaphragm valve, the rolling diaphragm part between the tray and the inner wall of the sleeve becomes an arc under the action of gas pressure. When the tray moves up and down, the arc rolls without sliding along the inner wall of the sleeve and the outer wall of the tray.

[0022] Preferably, the rolling diaphragm is installed forwardly or reversely between the valve body and the valve cover;

[0023] When installed in the forward direction, the rolling diaphragm is upright, and the Y-type diaphragm valve is used in situations where the pressure is relatively high. The upper part of the rolling diaphragm is assembled on the tray, the large opening of the rolling diaphragm is folded inward, and the two arc corners at the bottom are folded outward;

[0024] When installed in reverse, the rolling diaphragm is inverted, and the Y-type diaphragm valve is used in situations where the pressure is relatively low. The lower part of the rolling diaphragm is assembled on the tray, the large opening of the rolling diaphragm is folded outward, and the two arc corners on the top are folded inward.

[0025] Preferably, the factors affecting the stroke of the valve flap assembly include: rolling diaphragm height, rolling diaphragm inner corner radius, margin and rolling diaphragm thickness.

[0026] Preferably, when the rolling diaphragm is installed in the forward direction, the straight line segment at the bottom of the rolling diaphragm is equal to the straight line segment at the bottom of the tray, and the radius of the tray corner is equal to the radius of the inner corner of the rolling diaphragm;

[0027] When the rolling diaphragm is installed in reverse, the straight line segment at the bottom of the rolling diaphragm is equal to the straight line segment at the bottom of the tray, and the sum of the fillet radius of the tray and the thickness of the rolling diaphragm is less than or equal to the inner corner radius of the rolling diaphragm.

[0028] Preferably, when the Y-type diaphragm valve is closed, the internal pressure of the external gas source cavity is greater than the internal pressure of the medium gas source cavity, and the external gas source pushes the rolling diaphragm, the tray, the valve stem, and the valve flap assembly to move downward to close the liquid inlet cavity;

[0029] When the Y-type diaphragm valve is opened, the internal pressure of the external gas source cavity is lower than the internal pressure of the medium gas source cavity, and the medium gas source pushes the rolling diaphragm, tray, valve stem, and valve disc assembly to move upward to open the liquid inlet cavity.

[0030] Preferably, the valve flap assembly comprises a baffle, a buffer pad and a membrane flap which are sequentially assembled at the bottom end of the valve stem from top to bottom.

[0031] Preferably, the valve body is provided with a medium flow channel connected to the medium gas source cavity, and the valve cover is provided with an air source flow channel connected to the external air source cavity.

[0032] Beneficial effects of the utility model:

[0033] The rolling diaphragm structure provided by the utility model is designed so that the working stroke of the valve movement is independent of the outer diameter of the rolling diaphragm, but is related to the height of the rolling diaphragm, the radius of the inner corner circle of the rolling diaphragm, the margin and the thickness of the rolling diaphragm. A valve that meets the working conditions can be designed according to the valve structure size requirements.

[0034] The rolling diaphragm structure and Y-type diaphragm valve provided by the utility model have a valve movement working stroke that is independent of the valve size (rolling diaphragm diameter), and a valve that meets the working condition requirements can be designed according to the valve structure size requirements; when the diameter, material and thickness are the same as those of a disc diaphragm or a corrugated diaphragm, the valve can withstand higher pressure; the valve can open and close smoothly with little vibration and low noise; the number of times the valve opens and closes is much higher than that of a general diaphragm; when the tray or the valve stem is slightly deflected or eccentric, the valve will automatically be aligned under the action of the gas.

[0035] The utility model provides a Y-type diaphragm valve with a rolling diaphragm structure design, which increases the service life of the valve diaphragm by changing the diaphragm structure, avoids frequent diaphragm replacement, and saves maintenance costs; and the valve stroke is not affected by the size of the diaphragm, and the valve can be installed in a specific installation position. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a cross-sectional view of the Y-type diaphragm valve of the utility model;

[0037] Figure 2 This is a cross-sectional view of the rolling diaphragm of the utility model;

[0038] Figure 3 This is a schematic diagram of the forward installation of the rolling diaphragm of the utility model Figure 1 ;

[0039] Figure 4 This is a schematic diagram of the forward installation of the rolling diaphragm of the utility model Figure 2 ;

[0040] Figure 5 This is a schematic diagram of the forward installation of the rolling diaphragm of the utility model Figure 3 ;

[0041] Figure 6 This is a schematic diagram of the forward installation of the rolling diaphragm of the utility model Figure 4 ;

[0042] Figure 7 The reverse installation diagram of the rolling diaphragm of the utility model Figure 1 ;

[0043] Figure 8 The reverse installation diagram of the rolling diaphragm of the utility model Figure 2 ;

[0044] Fig. 9 The reverse installation diagram of the rolling diaphragm of the utility model Figure 3 ;

[0045] Fig.10 The reverse installation diagram of the rolling diaphragm of the utility model Figure 4 ;

[0046] Fig.11This is a schematic diagram of the forward installation dimensions of the rolling diaphragm of the utility model;

[0047] Fig.12 Cross-section of a comparative Y-type diaphragm valve Figure 1 ;

[0048] Fig.13 Cross-section of a comparative Y-type diaphragm valve Figure 2 ;

[0049] Reference numerals:

[0050] 1. Valve body; 11. Liquid inlet cavity; 12. Liquid outlet cavity; 13. Valve cavity; 14. External gas source cavity; 15. Medium gas source cavity; 16. Medium flow channel; 2. Valve cover; 21. Gas source flow channel; 3. Guide sleeve; 4. Valve stem; 5. Tray; 5', inner tray; 6. Rolling diaphragm; 61. Middle hole; 62. O-ring edge; 6', disc diaphragm; 7. Baffle; 8. Buffer pad; 9. Diaphragm petal; N and P are force points. DETAILED DESCRIPTION

[0051] The concept, specific structure and technical effects of the present invention will be clearly and completely described below in combination with the embodiments and drawings to fully understand the purpose, features and effects of the present invention.

[0052] Example 1

[0053] A Y-type diaphragm valve, such as Figure 1 As shown, it includes a valve body 1, a valve cover 2, a guide sleeve 3, a valve stem 4, a valve disc assembly, a tray 5 and a rolling diaphragm 6;

[0054] A three-way Y-shaped tube cavity is arranged in the valve body 1, and the Y-shaped tube cavity includes a liquid inlet tube cavity 11, a liquid outlet tube cavity 12 and a valve tube cavity 13. The valve cover 2 is assembled at the top of the valve tube cavity 13, the guide sleeve 3 is assembled inside the valve tube cavity 13, the valve stem 4 is slidably assembled in the guide sleeve 3, the bottom end of the valve stem 4 is assembled with a valve disc assembly for closing the liquid inlet tube cavity 11, and the top end is assembled with a tray 5. The inner end of the rolling diaphragm 6 is assembled on the tray 5, and the outer end is assembled between the valve body 1 and the valve cover 2. The rolling diaphragm 6 divides the cavity into an upper external gas source cavity 14 and a lower medium gas source cavity 15.

[0055] When the Y-type diaphragm valve is closed, the internal pressure of the external gas source cavity 14 is greater than the internal pressure of the medium gas source cavity 15, and the external gas source pushes the rolling diaphragm 6, the tray 5, the valve stem 4, and the valve disc assembly to move downward to close the liquid inlet cavity 11.

[0056] When the Y-type diaphragm valve is opened, the internal pressure of the external gas source cavity 14 is lower than the internal pressure of the medium gas source cavity 15 , and the medium gas source pushes the rolling diaphragm 6 , the tray 5 , the valve stem 4 , and the valve disc assembly to move upward to open the liquid inlet cavity 11 .

[0057] like Figure 1 As shown, the valve flap assembly includes a baffle 7, a buffer pad 8 and a membrane flap 9 which are sequentially assembled at the bottom end of the valve stem 4 from top to bottom, and are used to open or close the liquid inlet lumen 11.

[0058] like Figure 1 As shown, the valve body 1 is provided with a medium flow channel 16 connected to the medium gas source cavity 15, and the valve cover 2 is provided with an air source flow channel 21 connected to the external air source cavity 14. The medium flow channel 16 and the air source flow channel 21 are used to respectively introduce the medium gas source and the external air source into the medium gas source cavity 15 and the external gas source cavity 14, so that a pressure difference is generated between the medium gas source cavity 15 and the external gas source cavity 14, pushing the rolling diaphragm 6, the tray 5, the valve stem 4, and the valve disc assembly to move up and down, and opening or closing the liquid inlet cavity 11.

[0059] In this embodiment, the rolling diaphragm 6 has the following characteristics:

[0060] 1. The working stroke of the valve movement has nothing to do with the valve size (rolling diaphragm diameter). The valve that meets the working conditions can be designed according to the valve structure size.

[0061] 2. It can withstand higher pressure when the diameter, material and thickness are the same as those of disc diaphragm and corrugated diaphragm.

[0062] 3. Smooth opening and closing, small vibration and low noise.

[0063] 4. The opening and closing times are much higher than the general diaphragm life.

[0064] 5. When the tray or valve stem is slightly deflected or eccentric, it will automatically align under the action of gas.

[0065] like Figure 2 As shown, the rolling diaphragm 6 is in the shape of a top hat and is made of rubber sandwiched with silk cloth. A middle hole 61 is provided on the rolling diaphragm 6 , and O-ring edges 62 are provided on the top and bottom of the rolling diaphragm 6 .

[0066] In this embodiment, the rolling diaphragm 6 is shaped like a top hat in a free state. It is made of rubber sandwiched with silk cloth. The middle hole 61 on the top is used to install the valve stem. For installation, fixing and sealing, the top and bottom can have O-ring edges 62.

[0067] like Figure 3-Figure 6 , Figure 7-Figure 10 As shown, the internal cavity of the valve cover 2 and the upper cavity of the valve tube cavity 13 form a sleeve. During the closing and / or opening process of the Y-type diaphragm valve, the rolling diaphragm 6 is subjected to the action of gas pressure, and the part of the rolling diaphragm 6 between the tray 5 and the inner wall of the sleeve becomes an arc. When the tray 5 moves up and down, the arc rolls along the inner wall of the sleeve and the outer wall of the tray 5 without sliding.

[0068] In this embodiment, a tray 5 must be used in conjunction with the rolling diaphragm 6. After the rolling diaphragm 6 is installed, under the action of gas pressure, the portion between the tray 5 and the inner wall of the sleeve becomes an arc. When the tray 5 moves up and down, the arc rolls along the inner wall of the sleeve and the outer wall of the tray 5 without sliding, hence the name "rolling diaphragm".

[0069] like Figure 3-Figure 6 , Figure 7-Figure 10 As shown, the rolling diaphragm 6 is installed forwardly or reversely between the valve body 1 and the valve cover 2, the tray 5 is provided with a hat-shaped top of the rolling diaphragm 6, the outer wall of the tray 5 extends toward the bottom of the cap inside the rolling diaphragm 6 cap, and the rolling diaphragm 6 rolls in the sleeve and fits against the outer wall of the tray 5 when rolling.

[0070] like Figure 3-Figure 6 As shown, when installed in the forward direction, the top-hat-shaped rolling diaphragm 6 is upright, and the Y-type diaphragm valve is used in situations where the pressure is relatively high. The upper part of the top-hat-shaped rolling diaphragm 6 is assembled on the tray 5, and the large opening of the top-hat-shaped rolling diaphragm 6 is folded inward, and the two arc corners at the bottom are folded outward.

[0071] like Figure 7-Figure 10 As shown, when installed in reverse, the top-hat-shaped rolling diaphragm 6 is inverted, and the Y-type diaphragm valve is used in situations where the pressure is relatively low. The lower part of the top-hat-shaped rolling diaphragm 6 is assembled on the tray 5, and the large opening of the top-hat-shaped rolling diaphragm 6 is folded outward, and the two arc corners on the top are folded inward.

[0072] In this embodiment, there are two ways to install the rolling diaphragm 6. One is forward installation. Figure 3-Figure 6 , the other is reverse installation Figure 7-Figure 10 Forward installation is used in situations with relatively high pressure, and reverse installation is used in situations with relatively low pressure. For forward installation, the large opening of the diaphragm is folded inward; while for reverse installation, the two arc corners on the top of the diaphragm are folded inward.

[0073] In this embodiment, the factors affecting the stroke of the valve flap assembly include: the height of the rolling diaphragm, the radius of the inner corner of the rolling diaphragm, the margin, and the thickness of the rolling diaphragm.

[0074] like Fig.11 As shown, the rolling diaphragm should consider the size of the rolling width X. If the width is too large, the push (pull) force generated by the rolling diaphragm will be reduced, and the pressure on the rolling diaphragm will also be reduced. The rolling diaphragm is not as ideal as drawn in the figure. In fact, the diaphragm has many wrinkles along the inner wall of the sleeve and the outer surface of the tray. The thicker the rolling diaphragm, the larger the space occupied by the wrinkles. If the rolling width is too narrow, the wrinkles of the inner and outer layers of the diaphragm will rub against each other, affecting the rolling. According to practice, the utility model believes that the rolling width should meet the following conditions:

[0075] The rolling width of the rolling diaphragm is:

[0076] ;

[0077] Where, X is the rolling width of the rolling diaphragm (mm); is the rolling diaphragm thickness (mm);

[0078] The tray diameter and sleeve diameter meet the following requirements:

[0079] ;

[0080] in, ; ; d is the tray diameter (mm); D is the sleeve diameter (mm), and the sleeve is formed by the internal cavity of the valve cover and the upper cavity of the valve tube cavity.

[0081] The height of the tray and the rolling diaphragm are:

[0082] ;

[0083] ;

[0084] Among them, H t is the tray height; H is the rolling diaphragm height; L is the valve disc stroke; R is the tray fillet radius; C is the margin; X is the rolling width of the rolling diaphragm; R m is the inner corner radius of the rolling diaphragm.

[0085] When the rolling diaphragm is installed in the forward direction, the straight line section at the bottom of the rolling diaphragm is equal to the straight line section at the bottom of the tray, and the radius of the tray corner is equal to the radius of the inner corner of the rolling diaphragm;

[0086] When the rolling diaphragm is installed in reverse, the straight line segment at the bottom of the rolling diaphragm is equal to the straight line segment at the bottom of the tray, and the sum of the fillet radius of the tray and the thickness of the rolling diaphragm is less than or equal to the inner corner radius of the rolling diaphragm.

[0087] In this embodiment, when the rolling diaphragm is installed in the forward direction, the straight line segment at the bottom of the diaphragm should be aligned with the straight line segment d at the bottom of the tray. m The outer contour of the tray should be contained within the inner fillet of the diaphragm, so R=R m .

[0088] When the rolling diaphragm is installed in reverse, the straight line at the bottom of the diaphragm should also be aligned with the straight line at the bottom of the tray. m The sum of the tray corner radius and the diaphragm thickness should be slightly smaller than the diaphragm inner arc corner radius, that is, Considering that there will be small processing errors in the diaphragm valve parts, which will lead to deviations between the design position of the rolling diaphragm and the actual situation, and the rubber parts will shrink after vulcanization, therefore, combined with the size of the rolling diaphragm, the margin is generally between 2-8mm.

[0089] Comparative Example 1

[0090] The Y-type diaphragm valve used in Comparative Example 1 is as follows Fig.12 and Fig.13 As shown, it includes a valve body 1, a valve cover 2, a guide sleeve 3, a valve stem 4, upper and lower inner trays 5', a disc-shaped diaphragm 6', a baffle 7, a buffer pad 8, and a diaphragm 9.

[0091] The difference between Comparative Example 1 and Example 1 is that the upper and lower inner trays 5 ′ and the disc-shaped diaphragm 6 ′ are different from the tray 5 and the rolling diaphragm 6 of Example 1.

[0092] In comparative example 1, the original structure of the valve is as follows Fig.12 When the valve is closed, there is no medium in the valve body, the valve cover 2 is connected to an external gas source, and the external gas source is introduced into the external gas source cavity. There is no medium gas source in the medium gas source cavity. Due to the pressure difference, the external gas source pushes downward to close the valve.

[0093] When the valve is opened, the medium gas source is introduced into the medium gas source cavity. When the medium gas source pressure is greater than the external gas source, the valve stem 4 drives the baffle 7, the buffer pad 8, the diaphragm 9, the upper and lower inner trays 5', and the disc-shaped diaphragm 6' to move upward, and the disc-shaped diaphragm 6' will move as shown in the figure. Fig.13 Position, the moving position is subject to shear force. During the opening and closing process of the valve, each movement is subject to shear force, which shortens the life of the diaphragm. The force point of the diaphragm is at point P. According to the structural characteristics of the disc-type diaphragm, the larger the disc-type diaphragm stroke, the larger the disc-type diaphragm will be, which will lead to the valve cover and valve body becoming larger and larger, which is not conducive to installation.

[0094] In Example 1, Figure 1 As shown in the figure, when the rolling diaphragm is used on the diaphragm valve, it can be seen that due to the special structure of the rolling diaphragm, the stroke has nothing to do with the size (diameter) of the rolling diaphragm, but is related to the height of the rolling diaphragm, the radius of the inner corner of the rolling diaphragm, the margin and the thickness of the rolling diaphragm. According to the experiment, when the valve is working, the force point is always constant at point N. According to the upper pressure and lower pressure balance calculation formula: lower pressure * valve seat flow area = upper pressure * diaphragm force area. Under laboratory conditions, when the lower pressure * valve seat flow area > upper pressure * diaphragm force area, the valve is open and the medium flows in the inner cavity of the valve body. When the lower pressure * valve seat flow area < upper pressure * diaphragm force area, the valve is closed.

[0095] In the on-site life test, the disc-shaped diaphragm structure diaphragm valve was connected to an air source of 0.6MPa, and the valve body continuously passed a medium of 0.7MPa. The air source was closed every 3 seconds, exhausted for 2 seconds and then opened again, and the reciprocating motion lasted for 20,375 times. The balancing hole in the upper cavity of the valve began to leak and the front diaphragm was damaged.

[0096] The diaphragm valve with rolling diaphragm structure is connected to the gas source of 0.5MPa, and the valve body continuously passes the medium of 0.7MPa. The gas source is closed every 3 seconds, exhausted for 2 seconds and then opened again, and the reciprocating motion is continued for 115031 times. The valve is removed and the internal structure is checked. The diaphragm is still not damaged.

[0097] Structurally, this utility model patent changes the diaphragm structure, thereby increasing the service life of the valve diaphragm, avoiding frequent replacement of the diaphragm, and saving maintenance costs; and the valve stroke is not affected by the size of the diaphragm, and the valve can be installed in a specific installation position.

[0098] The implementation methods of the present invention are described in detail above, but the present invention is not limited to the described embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention, and these equivalents or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A rolling diaphragm structure, characterized in that: It comprises a tray (5) and a rolling diaphragm (6) assembled in a sleeve; The rolling diaphragm (6) is in the shape of a top hat and its bottom is fixedly mounted on the sleeve. The tray (5) is provided with the top of the rolling diaphragm (6). The outer wall of the tray (5) extends in the direction of the bottom of the cap inside the rolling diaphragm (6). The rolling diaphragm (6) rolls in the sleeve and the rolling diaphragm (6) is in contact with the outer wall of the tray (5) when rolling.

2. The rolling diaphragm structure according to claim 1, characterized in that: The rolling diaphragm (6) is made of rubber sandwiched with silk cloth, a middle hole (61) is provided on the rolling diaphragm (6), and O-ring edges (62) are provided on the top and bottom of the rolling diaphragm (6).

3. A Y-type diaphragm valve with a rolling diaphragm structure according to claim 1 or 2, characterized in that: It comprises a valve body (1), a valve cover (2), a guide sleeve (3), a valve stem (4), a valve disc assembly and a rolling diaphragm structure, wherein the rolling diaphragm structure comprises a tray (5) and a rolling diaphragm (6); The valve body (1) is provided with a three-way Y-shaped tube cavity, the Y-shaped tube cavity comprising a liquid inlet tube cavity (11), a liquid outlet tube cavity (12) and a valve tube cavity (13); the valve cover (2) is mounted on the top of the valve tube cavity (13); the guide sleeve (3) is mounted inside the valve tube cavity (13); the valve stem (4) is slidably mounted in the guide sleeve (3); the bottom end of the valve stem (4) is equipped with a valve flap assembly for closing the liquid inlet tube cavity (11); the top end is equipped with a tray (5); the inner end of the rolling diaphragm (6) is mounted on the tray (5), and the outer end is mounted between the valve body (1) and the valve cover (2); the rolling diaphragm (6) divides the cavity into an upper external gas source cavity (14) and a lower medium gas source cavity (15).

4. The Y-type diaphragm valve according to claim 3, characterized in that: The internal cavity of the valve cover (2) and the upper cavity of the valve tube cavity (13) form a sleeve. During the closing and / or opening process of the Y-type diaphragm valve, the rolling diaphragm (6) is subjected to the action of gas pressure, and the portion of the rolling diaphragm (6) between the tray (5) and the inner wall of the sleeve becomes an arc. When the tray (5) moves up and down, the arc rolls along the inner wall of the sleeve and the outer wall of the tray (5) without sliding.

5. The Y-type diaphragm valve according to claim 3, characterized in that: The rolling diaphragm (6) is installed in a forward direction or a reverse direction between the valve body (1) and the valve cover (2); When installed in the forward direction, the rolling diaphragm (6) is upright, and the Y-type diaphragm valve is used in situations where the pressure is relatively high. The upper part of the rolling diaphragm (6) is assembled on the tray (5), the large opening of the rolling diaphragm (6) is folded inwards, and the two arc corners at the bottom are folded outwards; When installed in reverse, the rolling diaphragm (6) is inverted. The Y-type diaphragm valve is used in situations where the pressure is relatively low. The lower part of the rolling diaphragm (6) is assembled on the tray (5). The large opening of the rolling diaphragm (6) is folded outwards, and the two arc corners on the top are folded inwards.

6. The Y-type diaphragm valve according to claim 5, characterized in that: When the rolling diaphragm is installed in the forward direction, the straight line section at the bottom of the rolling diaphragm is equal to the straight line section at the bottom of the tray, and the radius of the tray corner is equal to the radius of the inner corner of the rolling diaphragm; When the rolling diaphragm is installed in reverse, the straight line segment at the bottom of the rolling diaphragm is equal to the straight line segment at the bottom of the tray, and the sum of the fillet radius of the tray and the thickness of the rolling diaphragm is less than or equal to the inner corner radius of the rolling diaphragm.

7. The Y-type diaphragm valve according to claim 3, characterized in that: When the Y-type diaphragm valve is closed, the internal pressure of the external air source cavity (14) is greater than the internal pressure of the medium air source cavity (15), and the external air source pushes the rolling diaphragm (6), the tray (5), the valve stem (4), and the valve disc assembly to move downward to close the liquid inlet cavity (11); When the Y-type diaphragm valve is opened, the internal pressure of the external gas source cavity (14) is lower than the internal pressure of the medium gas source cavity (15), and the medium gas source pushes the rolling diaphragm (6), the tray (5), the valve stem (4), and the valve flap assembly to move upward to open the liquid inlet cavity (11).

8. The Y-type diaphragm valve according to claim 3, characterized in that: The valve flap assembly comprises a baffle (7), a buffer pad (8) and a membrane flap (9) which are sequentially assembled at the bottom end of the valve stem (4) from top to bottom.

9. The Y-type diaphragm valve according to claim 3, characterized in that: The valve body (1) is provided with a medium flow channel (16) connected to the medium gas source cavity (15), and the valve cover (2) is provided with an air source flow channel (21) connected to the external air source cavity (14).

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