diaphragm valve

Abstract

The application relates to a diaphragm valve, characterized in that the valve body, the valve cover, the diaphragm, the diaphragm being used to control the communication and disconnection of the input pipe and the output pipe, the pressing block being used to press the diaphragm to make the diaphragm control the communication and disconnection of the input pipe and the output pipe, the main valve rod being used to press the pressing block to make the pressing block press the diaphragm, the hand wheel being connected with the main valve rod and used to drive the main valve rod to rotate, the hand wheel moving along the axial direction of the main valve rod when the hand wheel and the main valve rod rotate, the boss of the valve cover being located in the moving direction of the hand wheel, and the hand wheel being blocked by the boss when the hand wheel contacts the boss. The diaphragm valve is convenient, safe and reliable to use.

Description

TECHNICAL FIELD

[0001] The present application relates to a diaphragm valve. BACKGROUND

[0002] The principle of the diaphragm valve is based on a diaphragm made of an elastomer, which is controlled manually or by other operations, and finally serves to close and open the valve. Through this design, liquid or gas and other fluid media only contact the valve body and the diaphragm, and do not contact other materials of the valve.

[0003] However, the existing diaphragm valve cannot display the stroke of the main valve rod when in use, so that the user cannot know the opening amplitude of the valve. When the main valve rod cannot continue to move and the passage is not completely cut off, the existing diaphragm valve cannot adjust the pressure on the diaphragm to completely cut off the passage, on the other hand, it also cannot limit the opening of the valve, and is not convenient to use. In addition, when the opening amplitude of the diaphragm valve reaches the requirement, there is no limit to the hand wheel, which may cause the hand wheel to be misoperated or loose, affecting the use. SUMMARY

[0004] One of the purposes of the present application is to overcome the deficiencies in the prior art and provide a diaphragm valve that is more convenient to use.

[0005] To achieve the above purpose, the present application realizes the following technical scheme:

[0006] The diaphragm valve is characterized in that it comprises:

[0007] A valve body is provided with an input pipe, a valve cavity and an output pipe, and the input pipe and the output pipe are in communication with the valve cavity;

[0008] A valve cover is provided with a first cavity, and the valve cover is connected with the valve body;

[0009] A diaphragm is connected with the valve cover and seals the first cavity, and the diaphragm covers the valve cavity with the valve cover; the diaphragm is used to control the communication and disconnection of the input pipe and the output pipe;

[0010] A pressing block is movably arranged in the first cavity, and the pressing block is used to abut against the diaphragm to control the communication and disconnection of the input pipe and the output pipe by the diaphragm;

[0011] A main valve rod penetrates the valve cover, one end of the main valve rod is located in the first cavity, and the other end of the main valve rod extends out of the first cavity, and the main valve rod is screwed with the valve cover; when the main valve rod moves, it can abut against the pressing block to make the pressing block abut against the diaphragm;

[0012] A hand wheel connected with the main valve rod for driving the main valve rod to rotate; the hand wheel moves along the axial direction of the main valve rod when the hand wheel rotates with the main valve rod;

[0013] The boss of the valve cover is located in the moving direction of the hand wheel, and the hand wheel is blocked by the boss when the hand wheel contacts the boss.

[0014] According to one embodiment of the present application, a stroke indicator is further included, the stroke indicator is tubular; a guide tube is arranged on the boss, the guide tube is connected with the boss and protrudes from the boss, the guide tube and / or the boss is threadedly connected with the main valve rod; the stroke indicator is sleeved on the guide tube.

[0015] According to one embodiment of the present application, the connecting structure of the stroke indicator and the guide tube is a tongue and a first groove; one of the tongue and the first groove is arranged on the stroke indicator, and the other is arranged on the guide tube; the tongue is inserted into the first groove.

[0016] According to one embodiment of the present application, a locking device is further included, a plurality of second grooves are arranged on the outer wall of the stroke indicator, and the second grooves are distributed in the circumferential direction; the hand wheel is sleeved outside the stroke indicator and can move relative to the stroke indicator; the locking device is connected with the hand wheel and can move relative to the hand wheel; the locking device penetrates the hand wheel and can be inserted into the second groove of the stroke indicator when the locking device moves; when the locking device is inserted into the second groove, the stroke indicator and the locking device limit the rotation of the hand wheel.

[0017] According to one embodiment of the present application, the locking device includes a sleeve locking device, a locking spring and a locking needle; the locking needle is connected with the sleeve locking device through the locking spring; the sleeve locking device is threadedly connected with the hand wheel; the locking needle penetrates the hand wheel and can move radially along the hand wheel; when the sleeve locking device rotates, the locking needle is driven to move radially along the hand wheel by the locking spring; the locking needle is arranged to be inserted into the second groove of the stroke indicator when the locking needle moves radially along the hand wheel; the rotation of the hand wheel is limited when the locking needle is inserted into the second groove.

[0018] According to one embodiment of the present application, a convex column is arranged on the hand wheel, and the convex column protrudes from the hand wheel; the convex column is provided with a radial through hole penetrating the convex column and the hand wheel; the sleeve locking device is threadedly connected with the convex column; the locking needle is located in the radial through hole and is movably arranged.

[0019] According to one embodiment of the present application, the hand wheel is provided with a driving cover assembly, which comprises a driving cover and a toothed washer connected with the driving cover; the toothed washer is connected with the hand wheel; the main valve rod penetrates the toothed washer and the driving cover, and the hand wheel drives the toothed washer to rotate through the driving cover when the hand wheel rotates, and the toothed washer drives the main valve rod to rotate when the toothed washer rotates.

[0020] According to one embodiment of the present application, the driving cover comprises a cover plate and a connecting column; the connecting column is provided with a plug-in pin; the connecting column is connected with the cover plate and protrudes from the cover plate, and the plug-in pin connects the toothed washer with the driving cover by penetrating the toothed washer.

[0021] According to one embodiment of the present application, the hand wheel is provided with a third counterbore at one end and a fourth counterbore at the other end, and the driving cover is partially inserted into the fourth counterbore; the toothed washer is provided with a plurality of teeth distributed in the circumferential direction; and the plurality of teeth are clamped in the fourth counterbore.

[0022] According to one embodiment of the present application, the fourth counterbore is provided with a plurality of protrusions spaced apart, and the plurality of protrusions are distributed in the circumferential direction; the teeth of each toothed washer are located between two protrusions; and the teeth and the protrusions cooperate to link the toothed washer with the hand wheel in rotation.

[0023] According to one embodiment of the present application, the main valve rod is provided with a first flange plate located in the valve cavity; when the main valve rod moves, the first flange plate is blocked by the valve cover to limit the stroke of the main valve rod.

[0024] According to one embodiment of the present application, the stroke limiting valve rod penetrates the main valve rod and protrudes from both ends of the main valve rod; the stroke limiting valve rod is threadedly connected with the main valve rod; one end of the stroke limiting valve rod is connected with a pressing block, and the other end of the stroke limiting valve rod extends out of the hand wheel.

[0025] According to one embodiment of the present application, the pressure block comprises a base and a connecting pipe; the connecting pipe is connected with the base and protrudes from the base; the connecting pipe is provided with a second cavity; the sidewall of the connecting pipe is provided with a first opening; the end of the connecting pipe is provided with a second opening; the first opening and the second opening are both in communication with the second cavity; the end of the travel limiting valve rod is provided with a second flange; the second flange can enter and exit the second cavity from the first opening; the second flange is larger than the second opening and is movably arranged in the second cavity; the travel limiting valve rod protrudes out of the second cavity from the second opening; the travel limiting valve rod is moved along the axial direction to abut against or lift the pressure block through the second flange to move the pressure block.

[0026] According to one embodiment of the present application, the hand wheel is provided with a driving cover assembly, the travel limiting valve rod penetrates through the hand wheel and the driving cover assembly, and the end of the travel limiting valve rod protruding out of the driving cover assembly is connected with a nut.

[0027] According to one embodiment of the present application, the color of the travel indicator is different from the colors of the hand wheel and the valve cover.

[0028] According to one embodiment of the present application, the color of the travel indicator is red.

[0029] In the diaphragm valve of the present application, the hand wheel is sleeved outside the travel indicator, so that the exposed amplitude of the travel indicator changes when the hand wheel is moved along the axial direction of the main valve rod. Therefore, the user can determine the opening amplitude of the diaphragm valve according to the height of the travel indicator. When the hand wheel is moved downward to abut against the boss, it cannot be moved further, so the boss of the valve cover can limit the travel of the hand wheel and provide the stop function of the hand wheel. When the main valve rod is moved downward to abut against the pressure block to the lowest position and still cannot make the elastic diaphragm tightly adhere to the valve weir to block the valve cavity, the nut is rotated to move away from the driving cover, and then the travel limiting valve rod is rotated to abut against the pressure block and further abut against the elastic diaphragm, so that the elastic diaphragm tightly adheres to the valve weir. When the main valve rod is moved upward to remove the abutment of the pressure block against the elastic diaphragm and make the elastic diaphragm open to the maximum amplitude, the travel limiting valve rod is rotated to move downward, and the elastic diaphragm can be adjusted by the pressure block. Therefore, the present application can adjust the opening of the elastic diaphragm by the main valve rod and the travel limiting valve rod respectively, the travel limiting valve rod provides the supplementary closing function when the main valve rod cannot completely close the diaphragm valve, and the use is convenient, safe and reliable. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the diaphragm valve in the present application.

[0031] Figure 2A-A sectional view of the diaphragm valve in the present application.

[0032] Figure 3 A-A sectional view of the diaphragm valve in the present application. Figure 2

[0033] Figure 4 A-A sectional view of the diaphragm valve in the present application.

[0034] Figure 5 A-A sectional view of the diaphragm valve in the present application. Figure 4 A-A sectional view of the diaphragm valve in the present application.

[0035] Figure 6 A-A sectional view of the diaphragm valve in the present application.

[0036] Figure 7 A-A sectional view of the diaphragm valve in the present application.

[0037] Figure 8 A-A sectional view of the diaphragm valve in the present application.

[0038] Figure 9 A-A sectional view of the diaphragm valve in the present application.

[0039] Figure 10 A-A sectional view of the diaphragm valve in the present application.

[0040] Figure 11 A-A sectional view of the diaphragm valve in the present application.

[0041] Figure 12 A-A sectional view of the diaphragm valve in the present application.

[0042] Figure 13 A-A sectional view of the diaphragm valve in the present application.

[0043] Figure 14 A-A sectional view of the diaphragm valve in the present application.

[0044] Figure 15 A-A sectional view of the diaphragm valve in the present application. DETAILED DESCRIPTION

[0045] A-A sectional view of the diaphragm valve in the present application. Figures 1 to 6 ​As shown, the diaphragm valve 100 includes a valve body 110, a valve cover 120, a diaphragm 130, a pressing block 140, a main valve rod 150 and a hand wheel 160. The valve body 110 is provided with an input pipe 111, a valve cavity 112 and an output pipe 113, the input pipe 111 and the output pipe 113 are communicated with the valve cavity 112. The diaphragm 130 and the pressing block 140 are arranged in the valve cavity 112. The hand wheel 160 drives the main valve rod 150 to rotate and move axially along the main valve rod 150. When the main valve rod 150 moves axially, it presses the diaphragm 130 or releases the pressing on the diaphragm 130, so that the diaphragm 130 controls the communication and disconnection of the input pipe 111 and the output pipe 113.

[0046] The valve cavity 112 of the valve body 110 is provided with a valve weir 114. The periphery of the diaphragm 130 is connected with the valve cover 120, the valve cover 120 is connected with the valve body 110, and the valve cavity 112 is sealed. When the diaphragm 130 is pressed against the valve weir 114, the input pipe 111 and the output pipe 113 are cut off. When the diaphragm 130 is not pressed against the valve weir 114, the input pipe 111 and the output pipe 113 are communicated.

[0047] As shown, Figures 1 to 6 The valve cover 120 includes a bottom plate 121, a boss 122 and a guide pipe 123. The boss 122 is connected with the bottom plate 121 and protrudes from the bottom plate 121. The guide pipe 123 is arranged on the boss 122 and protrudes from the boss 122. The guide pipe 123 is tubular, the inner wall is provided with internal threads, and the outer wall is provided with a first groove 124. The valve cover 120 is provided with a first cavity 125. The inner wall of the boss 122 is provided with a guide rib 126.

[0048] As shown, Figures 1 to 7 , Figure 8 The diaphragm 130 includes a mounting plate 131 and an elastic diaphragm 132. The mounting plate 131 is arranged around the elastic diaphragm 132 and connected with the elastic diaphragm 132. The elastic diaphragm 132 is provided with a circular truncated cone 133 in the middle. The circular truncated cone 133 is connected with a flexible suspension 135 through a screw rod 134.

[0049] The bottom plate 121 and the mounting plate 131 are connected with the valve body 110. The mounting plate 131 is located between the bottom plate 121 and the valve body 110. The elastic diaphragm 130 covers the first cavity 125 and the valve cavity 112.

[0050] As shown, Figure 3 , Figure 6 , Figure 9As shown, the pressure block 140 comprises a base 141 and a connecting tube 142. The connecting tube 142 is connected to the base 141 and protrudes from the base 141. The pressure block 140 is provided with a second cavity 143. The sidewall 144 of the connecting tube 142 is provided with a first opening 145. The end 146 of the connecting tube 142 is provided with a second opening 147. The first opening 145 and the second opening 147 are both in communication with the second cavity 143. The base 141 is provided with a first counterbore 1411. The depth of the first counterbore 1411 can be determined according to actual needs, for example, the first counterbore 1411 can extend to the connecting tube 142. The first counterbore 1411 is provided with a first through hole 1412. The second cavity 143 is provided with a second counterbore 1413. The first through hole 1412 is in communication with the first counterbore 1411 and the second counterbore 1413. The pressure block 140 is further provided with a guide groove 148. The guide groove 148 is connected to the base 141 and the connecting tube 142.

[0051] The pressure block 140 is located in the second cavity 143 and can move in the second cavity 143. The guide protrusion 126 is inserted into the guide groove 148 and can slide in the guide groove 148. The guide protrusion 126 cooperates with the guide groove 148 to limit the relative rotation between the pressure block 140 and the valve cover 120, and only allows linear movement. The circular truncated cone 133 of the elastic diaphragm 132 is located in the first counterbore 1412. The screw rod 134 passes through the pressure block 140 from the first through hole 1412. The flexible suspension 135 is located in the second counterbore 1413, and the elastic diaphragm 132 is connected to the pressure block 140 through the flexible suspension 135.

[0052] As shown in Figure 3 , 4 , 5, 8, 10, the diaphragm valve 100 further comprises a stroke limiting valve rod 170. The stroke limiting valve rod 170 is a screw rod, and the end is provided with a second flange plate 171. The second flange plate 171 can enter and exit the second cavity 143 from the first opening 145. The second flange plate 171 is larger than the first opening 147 and cannot exit the second cavity 143 from the second opening 147. The stroke limiting valve rod 170 extends out of the second cavity 143 from the second opening 147. When the second flange plate 171 is located in the second cavity 143, it can move in the second cavity 143.

[0053] When the stroke limiting valve rod 170 moves axially, the second flange plate 171 can abut against the pressure block 140 and the elastic suspension 135, thereby causing the pressure block 140 and the elastic suspension 135 to abut against the elastic diaphragm 132.

[0054] As shown in Figure 3 , 4The main valve rod 150 is provided with external threads and a lumen, and the lumen is provided with internal threads. The main valve rod 150 is provided with a first flange 151 at an end thereof. The main valve rod 150 is sleeved on the stroke limiting valve rod 170, and the two are threadedly connected, and the stroke limiting valve rod 170 protrudes from the main valve rod 150 at both ends. The main valve rod 150 penetrates the guide tube 123 and is threadedly connected with the guide tube 123, and the first flange 151 is located in the first cavity 125. The first flange 151 is located above the pressing block 140. When the main valve rod 150 moves in the axial direction, the first flange 151 can abut against the end 146 of the connecting pipe 142, so that the pressing block 140 moves.

[0055] As shown in Figure 3 , 4 , 11, the stroke indicator 180 is tubular, and the inner wall is provided with a tongue 181. One end of the stroke indicator 180 is provided with a plurality of second grooves 182. The plurality of second grooves 182 are distributed in a circle along the outer wall of the stroke indicator 180. The other end of the stroke indicator 180 is sleeved on the guide tube 123, and the tongue 181 is inserted into the first groove 124, so that the stroke indicator 180 is connected with the guide tube 123 by clamping. In this embodiment, the stroke indicator 180 adopts a bright color, such as red. Moreover, the color of the stroke indicator 180 is different from the colors of the valve cover 120 and the hand wheel 160.

[0056] As shown in Figure 1 , 2 , 3, 12, 13, the hand wheel 160 is columnar in shape, and is provided with a third counterbore 161 at one end in the axial direction and a fourth counterbore 162 at the other end. The third counterbore 161 is provided with an extension pipe 163. The extension pipe 163 protrudes from the bottom wall of the third counterbore 161. The outer diameter of the extension pipe 163 is smaller than the diameter of the third counterbore 161. The hand wheel 160 is further provided with a through hole 164. The through hole 164 extends from the bottom wall of the fourth counterbore 162 to the end of the extension pipe 163, and communicates the third counterbore 161 and the fourth counterbore 162. The through hole 164 is provided with internal threads. A plurality of protrusions 167 are arranged on the bottom wall 166 of the fourth counterbore 162 at intervals. The outer wall of the hand wheel 160 is provided with a protruding column (not shown in the figure). The protruding column is provided with a radial through hole 168. The radial through hole 168 extends to communicate with the third through hole 161.

[0057] The hand wheel 160 is sleeved outside the stroke indicator 180, and the two can move relative to each other. One end of the stroke indicator 180 is located in the third counterbore 161 and between the inner wall of the hand wheel 160 and the extension pipe 163. The main valve rod 150 penetrates the hand wheel 160 from the through hole 164, and the external threads of the main valve rod 150 are matched with the internal threads in the through hole 164.

[0058] As shown in Figure 14The locking device 190 includes a sleeve locking device 191, a locking spring 192 and a locking pin 193. The sleeve locking device 191 is threadedly connected with the convex column 165. The locking spring 192 is connected with the sleeve locking device 191 at one end and with the locking pin 193 at the other end. The locking spring 192 is sleeved on the locking pin 193. The locking pin 193 is arranged in the radial through hole 168 and is movable. The locking pin 193 penetrates the hand wheel 160 and is movable along the radial direction of the hand wheel 160.

[0059] When the sleeve locking device 191 rotates, the locking pin 193 is moved along the radial direction of the hand wheel 160 by the locking spring 192. When the locking pin 193 moves along the radial direction of the hand wheel 190, the locking pin 193 is arranged in the second groove 182 of the stroke indicator 180. When the locking pin 193 is arranged in the second groove 182, the rotation of the hand wheel 160 is limited.

[0060] As shown in Figure 15 The diaphragm valve 100 further includes a driving cover assembly 102. The driving cover assembly 102 includes a driving cover 103 and a toothed washer 104. The driving cover 103 includes a cover plate 105 and a connecting column 106. The connecting column 106 is connected with the cover plate 105 and protrudes from the cover plate 105. The connecting column 106 is provided with a plug pin 107 at the end. The toothed washer 104 is provided with a ring of teeth 108 around the periphery. The plug pin 107 penetrates the toothed washer 104, connecting the toothed washer 104 and the connecting column 106 together.

[0061] The connecting column 106 is located in the fourth counterbore 162, and the driving cover 103 is tightly connected with the hand wheel 160. The teeth 108 of the toothed washer 104 are distributed between the convex blocks 167, and the relative rotation of the toothed washer 104 and the hand wheel 160 is limited. The toothed washer 104 is sleeved on the main valve rod 150 and rotates with the main valve rod 150. When the hand wheel 160 rotates, the toothed washer 104 is driven to rotate by the driving cover 103, and the main valve rod 150 is driven to rotate by the toothed washer 104 when the toothed washer 104 rotates. The stroke limiting valve rod 170 penetrates the cover plate 105 of the driving cover 103. The stroke limiting valve rod 170 is provided with a nut 172. When the nut 172 is screwed, it abuts against the cover plate 105 of the driving cover 103.

[0062] When the diaphragm valve 100 of this invention is in use, rotating the handwheel 160 can drive the main valve stem 150 to rotate via the drive cover 103 and the toothed washer 104. The main valve stem 150 is threadedly connected to the valve cover 120, and the valve cover 120 is fixed. Therefore, when the main valve stem 150 rotates, it will move axially. When the main valve stem 150 moves axially, the first flange 171 abuts against the pressure block 140, and the pressure block 140 abuts against the elastic diaphragm 132, pressing the elastic diaphragm 132 against the valve weir 114, isolating the valve chamber 112, and cutting off the connection between the input pipe 111 and the output pipe 113. Rotating the handwheel 160 in the opposite direction can release the pressure block 140 from pressing against the elastic diaphragm 132, opening the valve chamber 112, and connecting the input pipe 111 and the output pipe 113.

[0063] The handwheel 160 is mounted outside the stroke indicator 180. Therefore, when the handwheel 180 moves axially along the main valve stem 150, the extent to which the stroke indicator 180 is exposed will change. Thus, the user can determine the opening extent of the diaphragm valve 100 based on the height of the visible stroke indicator 180. Figure 1 As shown, when the handwheel 160 moves downwards and abuts against the boss 122, it cannot move further. Therefore, the boss 122 of the valve cover 120 can limit the stroke of the handwheel 160, providing a stopping function for the handwheel 160. When the main valve stem 150 pushes down against the pressure block 140 to its lowest position, but still cannot make the elastic diaphragm 132 tightly adhere to the valve weir 114 to isolate the valve chamber 112, the nut 172 is rotated to move the nut 172 away from the drive cover 103. Then, the stroke-limiting valve stem 170 can be rotated to abut against the pressure block 140, and then against the elastic diaphragm 132, making the elastic diaphragm 132 tightly adhere to the valve weir 114. Figure 3 As shown, when the main valve stem 150 moves upward, the pressure block 140 releases its pressure on the elastic diaphragm 132, allowing the elastic diaphragm 132 to open to its maximum extent. Rotating the stroke limiting valve stem 170 causes it to move downward, allowing the pressure block 140 to press against the elastic diaphragm 132, thus reducing the opening degree of the diaphragm valve 132 and adjusting the opening degree of the diaphragm valve 100. Therefore, this invention allows for the adjustment of the elastic diaphragm opening degree using both the main valve stem and the stroke limiting valve stem. The stroke limiting valve stem provides a supplementary closing function when the main valve stem cannot fully close the diaphragm valve, making it convenient, safe, and reliable.

[0064] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions or improvements within the spirit of the present invention are covered within the scope of the claims of the present invention.

Claims

1. A diaphragm valve, characterized in that, include: The valve body is provided with an input pipe, a valve cavity, and an output pipe, wherein the input pipe and the output pipe are both connected to the valve cavity; A valve cover, comprising a base plate and a boss, the boss being connected to and protruding from the base plate; the valve cover having a first cavity; the valve cover being connected to the valve body; A diaphragm is connected to the valve cover and seals the first cavity; the diaphragm and the valve cover cover the valve cavity; the diaphragm is used to control the connection and disconnection of the input pipe and the output pipe. A pressure block is movably disposed within the first cavity, and the pressure block is used to press against the diaphragm to allow the diaphragm to control the connection and disconnection of the input tube and the output tube; The main valve stem passes through the valve cover, with one end located inside the first cavity and the other end extending outside the first cavity. The main valve stem is threadedly engaged with the valve cover. When the main valve stem moves, it can abut against the pressure block so that the pressure block abuts against the diaphragm. A handwheel, connected to the main valve stem, is used to drive the main valve stem to rotate; when the handwheel and the main valve stem rotate, they move along the axial direction of the main valve stem. The boss on the valve cover is located in the direction of movement of the handwheel, and the handwheel is blocked by the boss when it comes into contact with the boss; It also includes a stroke limiting valve stem, which passes through the main valve stem and protrudes from the main valve stem at both ends; the stroke limiting valve stem is threadedly connected to the main valve stem; one end of the stroke limiting valve stem is connected to the pressure block, and the other end extends beyond the handwheel; The pressure block includes a base and a connecting pipe; the connecting pipe is connected to the base and protrudes from the base; the connecting pipe is provided with a second cavity; the side wall of the connecting pipe is provided with a first opening; the end of the connecting pipe is provided with a second opening; both the first opening and the second opening communicate with the second cavity; the end of the stroke limiting valve stem is provided with a second flange; the second flange can enter the cavity through the first opening and exit the cavity, the second flange is larger than the second opening, and the second flange can be movably disposed within the cavity; the stroke limiting valve stem extends out of the cavity from the second opening; when the stroke limiting valve stem moves axially, it moves the pressure block by pressing or lifting the pressure block through the second flange.

2. The diaphragm valve according to claim 1, characterized in that, It also includes a stroke indicator, which is tubular; a guide tube is provided on the boss, the guide tube is connected to the boss and protrudes from the boss, and the guide tube and / or the boss are threadedly engaged with the main valve stem; the stroke indicator is fitted on the guide tube.

3. The diaphragm valve according to claim 2, characterized in that, The connection structure between the travel indicator and the guide tube is a tenon and a first groove; one of the tenon and the first groove is provided on the travel indicator and the other is provided on the guide tube; the tenon is inserted into the first groove.

4. The diaphragm valve according to claim 2, characterized in that, It also includes a locking device. The outer wall of the travel indicator is provided with a plurality of second grooves, which are distributed along the circumferential direction. The handwheel is fitted outside the travel indicator and can move relative to the travel indicator. The locking device is connected to the handwheel and can be movably disposed relative to the handwheel. The locking device passes through the handwheel and can be inserted into the second groove of the travel indicator when it is in motion. When the locking device is inserted into the second groove, it restricts the rotation of the handwheel by the travel indicator and the locking device.

5. The diaphragm valve according to claim 4, characterized in that, The locking device includes a sleeve locking device, a locking spring, and a locking pin; the locking pin is connected to the sleeve locking device via the locking spring; the sleeve locking device is threadedly connected to the handwheel; the locking pin passes through the handwheel and can move radially along the handwheel; when the sleeve locking device rotates, the locking spring drives the locking pin to move radially along the handwheel; when the locking pin moves radially along the handwheel, it can be inserted into the second groove of the travel indicator; when the locking pin is inserted into the second groove, it restricts the rotation of the handwheel.

6. The diaphragm valve according to claim 5, characterized in that, The handwheel is provided with a protruding post that protrudes from the handwheel; the protruding post is provided with a radial through hole that passes through the protruding post and the handwheel; the sleeve locking device is threadedly connected to the protruding post; the locking pin is located in the radial through hole and is movably disposed.

7. The diaphragm valve according to claim 1, characterized in that, The handwheel is provided with a drive cover assembly, which includes a drive cover and a toothed washer. The toothed washer is connected to the drive cover and the handwheel. The main valve stem passes through the toothed washer and the drive cover. When the handwheel rotates, it drives the toothed washer to rotate through the drive cover. When the toothed washer rotates, it drives the main valve stem to rotate.

8. The diaphragm valve according to claim 7, characterized in that, The drive cover includes a cover plate and a connecting post; the connecting post is provided with a pin; the connecting post is connected to the cover plate and protrudes from the cover plate, and the pin passes through the toothed washer to connect the toothed washer to the drive cover.

9. The diaphragm valve according to claim 7, characterized in that, The handwheel has a third countersunk hole at one end and a fourth countersunk hole at the other end, and the drive cover is partially inserted into the fourth countersunk hole; the toothed washer has multiple teeth, which are distributed along the circumferential direction; the multiple teeth are engaged in the fourth countersunk hole.

10. The diaphragm valve according to claim 9, characterized in that, The fourth countersunk hole is provided with a plurality of protrusions at intervals, and the plurality of protrusions are distributed along the circumferential direction; the teeth of each toothed washer are located between two protrusions; the teeth and the protrusions cooperate to connect the toothed washer to the handwheel for linkage rotation.

11. The diaphragm valve according to claim 1, characterized in that, The main valve stem is provided with a first flange, which is located inside the valve cavity; when the main valve stem moves, the first flange is blocked by the valve cover, which restricts the stroke of the main valve stem.

12. The diaphragm valve according to claim 1, characterized in that, The handwheel is provided with a drive cover assembly, the stroke limiting valve rod passes through the handwheel and the drive cover assembly, and a nut is connected to one end of the stroke limiting valve rod that extends out of the drive cover assembly.

13. The diaphragm valve according to claim 2, characterized in that, The color of the travel indicator is different from the color of the handwheel and the valve cover.

14. The diaphragm valve according to claim 2 or 13, characterized in that, The travel indicator is red.

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