A new type of stem-disc connection structure of a pilot shut-off valve

Abstract

The utility model provides a novel pilot cut-off valve's valve stem valve clack connecting structure, including the valve clack and valve stem, the both sides of the upside of valve clack are equipped with the symmetrical embrace and hold part, embrace and hold part includes the vertical part that extends upwards, the vertical part is equipped with the horizontal part that extends to the valve clack center, and two horizontal parts are spaced apart; The valve stem is connected between two embrace and hold parts, and the both sides of valve stem are equipped with the connecting groove that penetrates the front and back two sides of valve stem respectively, and the horizontal part extends into the connecting groove and embrace and hold on the valve stem. Its valve stem and valve clack are in movable connection state, and the valve stem is installed on the valve cover and can move up and down, and the valve stem will not rotate, and the valve clack and valve body slide up and down, and the valve clack will not rotate, and the valve stem moves up and down and drives the valve clack to move up and down. In this way, even if the valve stem installation exists error and cannot keep coaxial with the valve seat, the valve clack and valve seat coaxial will not be affected.

Description

Technical Field

[0001] This utility model relates to the field of gate valve technology, specifically to a novel valve stem and valve disc connection structure for a pilot gate valve. Background Technology

[0002] As a key control component in fluid transport systems, gate valves are widely used in industrial and civil fields such as petroleum, chemical, power, and water supply and drainage. Their core function is to achieve reliable cut-off or regulation of fluid through the precise fit between the valve disc and the valve seat.

[0003] In the existing structural design of gate valves, the valve stem and valve disc are mostly fixedly connected. This connection structure has revealed some problems in actual assembly and use: due to the machining tolerances of the valve body and valve cover, as well as the unavoidable cumulative errors during assembly, and since the valve cover is connected to the valve body, the valve stem is connected to the valve cover, and the valve disc is connected to the valve stem, it may be difficult to ensure a strict coaxial state between the valve disc and the valve seat after installation.

[0004] When the valve is closed, axial misalignment prevents the valve disc and seat from achieving full and uniform contact, resulting in a one-sided sealing condition. To achieve the desired sealing effect, greater axial pressure needs to be applied to the valve disc via the valve stem, forcing the valve disc to deform and conform to the valve seat. However, this one-sided contact pattern between the valve disc and seat causes excessive friction and compression on the local sealing surface, accelerating wear and failure of the sealing surface and significantly shortening the valve's service life. Utility Model Content

[0005] In view of the problems pointed out in the background art, this utility model proposes a novel valve stem and valve disc connection structure for a pilot shut-off valve to solve the above-mentioned technical problems.

[0006] The technical solution of this utility model is implemented as follows: A novel valve stem and valve disc connection structure for a pilot-operated shut-off valve includes a valve disc and a valve stem. The upper side of the valve disc has symmetrical clamping portions on its left and right sides. Each clamping portion includes an upwardly extending vertical portion and a horizontal portion extending towards the center of the valve disc. The two horizontal portions are spaced apart. The valve stem is connected between the two clamping portions. The left and right sides of the valve stem have connecting grooves that penetrate the front and rear sides of the valve stem. The horizontal portions extend into the connecting grooves and clamp onto the valve stem.

[0007] The present invention is further provided in that the valve disc is provided with guide grooves that penetrate its upper and lower sides on its front and rear sides respectively.

[0008] The present invention is further configured such that the distance between the vertical sidewalls of the two connecting grooves gradually increases from top to bottom; in the natural state, the distance between the two horizontal parts is L, which is greater than or equal to the distance between the upper ends of the vertical sidewalls of the two connecting grooves, and less than the distance between the lower ends of the vertical sidewalls of the two connecting grooves.

[0009] The present invention is further configured such that when the lower end of the valve stem abuts against the upper side of the valve disc, the lower side of the horizontal portion and the lower side of the connecting groove are spaced vertically apart.

[0010] The present invention is further configured such that when the lower end of the valve stem abuts against the upper side of the valve disc, the distance between the lower side of the horizontal portion and the lower side of the connecting groove is 3-7mm.

[0011] The present invention is further configured such that, in the vertical direction, the width of the connecting groove is greater than the thickness of the horizontal portion.

[0012] The present invention is further configured such that the lower side of the valve disc forms a sealing surface that mates with the valve seat.

[0013] The present invention is further configured such that the clamping part and the valve disc are integrally formed.

[0014] The present invention is further configured such that the upper end of the valve stem is provided with an external thread.

[0015] The present invention is further configured such that, in the front-to-back direction, the width of the clamping part is greater than the diameter of the valve stem.

[0016] By adopting the above technical solution, the beneficial effects of this utility model are as follows: The novel pilot-operated shut-off valve provided by this utility model has a valve stem and valve disc connection structure in which the valve stem and valve disc are in a movable connection state. The valve stem is installed on the valve cover and can move up and down without rotating. The valve disc slides up and down with the valve body (the inner wall of the valve body is provided with a guide rail that slides with the guide groove on the valve disc). The valve disc does not rotate, and the up and down movement of the valve stem drives the valve disc to move up and down.

[0017] In this way, even if the valve stem cannot be kept coaxial with the valve seat due to errors in installation, it will not affect the coaxiality of the valve disc and the valve seat.

[0018] In this way, when the valve disc moves downward, it can achieve full and uniform contact with the valve seat, and will not form one-sided contact.

[0019] Moreover, the valve stem does not drive the valve disc to rotate, so there will be no rotational friction wear between the valve disc and the valve seat. Attached Figure Description

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

[0021] Figure 1 This is a schematic diagram of the structure of this utility model.

[0022] Figure 2 This is a cross-sectional view of the present invention.

[0023] Figure 3 This is a schematic diagram of the valve disc of this utility model.

[0024] Figure 4 This is a schematic diagram of the valve stem of this utility model.

[0025] The following are the labels in the attached diagram: 1. Valve disc; 2. Valve stem; 3. Vertical part; 4. Horizontal part; 5. Connecting groove; 6. Guide groove; 7. External thread. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] For reference as follows Figures 1-4 The present invention will be described as follows: Example: A novel valve stem and valve disc connection structure for a pilot-operated shut-off valve, comprising a valve disc 1 and a valve stem 2.

[0028] The upper side of valve disc 1 is provided with symmetrical clamping parts on the left and right sides, which are the structure connecting valve disc 1 and valve stem 2.

[0029] The clamping part includes an upwardly extending vertical portion 3, which serves to provide support for the horizontal portion 4.

[0030] The upper end of the vertical part 3 is provided with a horizontal part 4 extending toward the center of the valve disc 1, and two horizontal parts 4 are arranged at intervals.

[0031] The valve stem 2 is connected between two clamping parts. The left and right sides of the valve stem 2 are respectively provided with connecting grooves 5 that pass through the front and rear sides of the valve stem 2. The horizontal part 4 extends into the connecting grooves 5 and clamps onto the valve stem 2.

[0032] The valve disc 1 has guide grooves 6 running through its upper and lower sides on both the front and rear sides. The cross-sectional shape and size of the guide grooves 6 are strictly matched with the guide rails on the inner wall of the valve body. This structure is the key to restricting the movement of the valve disc 1, ensuring that the valve disc 1 can only slide up and down along the axial direction of the valve body and cannot rotate circumferentially.

[0033] The valve stem 2 is installed in the pre-set mounting hole in the valve cover of the valve body. The valve stem 2 can only move up and down along the axial direction and cannot rotate circumferentially, which provides a basis for the subsequent stable movement of the valve disc 1.

[0034] During assembly, the valve stem 2 is inserted between the two clamping parts of the valve disc 1. At this time, the horizontal part 4 of the clamping part extends into the connecting groove 5 of the valve stem 2. Through the cooperation between the horizontal part 4 and the connecting groove 5, the initial connection between the valve disc 1 and the valve stem 2 is achieved. However, this connection is not completely fixed and does not restrict the relative movement of the two in the vertical direction, so that the valve stem 2 and the valve disc 1 are in a movable connection state, rather than a traditional rigid fixation.

[0035] The valve disc 1 and the inner wall of the valve body form a sliding fit. The inner wall of the valve body has a pre-set guide rail that matches the guide groove 6 of the valve disc 1. The guide rail is embedded in the guide groove 6. Through the sliding fit between the guide rail and the guide groove 6, the valve disc 1 is constrained in a circumferential direction, which restricts the rotation of the valve disc 1 and only allows the valve disc 1 to slide along the guide rail direction (up and down direction), ensuring that the movement trajectory of the valve disc 1 is always consistent with the axis of the valve body and the axis of the valve seat.

[0036] When the valve stem 2 moves vertically, it transmits axial force to the clamping part of the valve disc 1 through the contact between the connecting groove 5 and the horizontal part 4. This, in turn, drives the valve disc 1 to move vertically along the valve body guide rail, thus realizing the opening and closing of the valve. During this process, since the valve stem 2 and the valve disc 1 are movably connected and are constrained by the valve cover and valve body respectively, they maintain a stable motion posture, achieving effective power transmission while avoiding mutual interference.

[0037] In traditional fixed connection structures, if there is an error in the installation of the valve stem, it will directly lead to a deviation in the coaxiality of the valve disc and the valve seat. In this structure, the valve stem 2 and the valve disc 1 are movably connected, and the movement of the valve disc 1 is guided and constrained by the valve body guide rail alone.

[0038] Even if the valve stem 2 cannot maintain the coaxiality with the valve seat due to installation errors (such as deviation in the machining of the valve cover mounting hole, or misalignment of the valve stem itself), the movement trajectory of the valve disc 1 is individually limited by the valve body guide rail (which cooperates with the guide groove 6), so the axis of the valve disc 1 always remains consistent with the axis of the valve seat and is not affected by the coaxiality deviation of the valve stem 2.

[0039] Based on the above coaxiality guarantee, when the valve is closed, the valve disc 1 moves downward along the guide rail. Since its axis is strictly aligned with the valve seat axis, the sealing surface of the valve disc 1 can completely cover the sealing surface of the valve seat, achieving full and uniform contact, rather than the single-sided contact in the traditional structure.

[0040] The distance between the vertical sidewalls of the two connecting grooves 5 gradually increases from top to bottom, that is, the cross-section of the connecting groove 5 has a gradual change shape of "narrow at the top and wide at the bottom", and the inclination angles of the two sidewalls are symmetrical, ensuring that the force is balanced when the subsequent horizontal part 4 comes into contact with the sidewall.

[0041] In its natural state (when not subjected to external pressure), the distance between the two horizontal parts 4 is L.

[0042] L is greater than or equal to the distance between the upper ends of the vertical sidewalls of the two connecting grooves 5, ensuring that the horizontal part 4 can smoothly extend into the upper region of the connecting groove 5, and in this position, there is no pre-tightening force or very little pre-tightening force between the outer wall of the horizontal part 4 and the vertical sidewall of the connecting groove 5.

[0043] L is less than the distance between the lower ends of the vertical sidewalls of the two connecting grooves 5. This dimension design is key to achieving preload adjustment. When the horizontal part 4 moves downward along the connecting groove 5, the horizontal part 4 will be subjected to outward squeezing force applied by the sidewalls due to the gradual increase in the distance between the sidewalls of the connecting grooves 5, which will then produce elastic deformation and form a larger clamping preload force on the valve stem 2.

[0044] When the horizontal part 4 is clamped at the upper end of the vertical sidewall of the connecting groove 5: because the distance L between the horizontal parts 4 is greater than or equal to the distance between the upper sidewalls of the connecting groove 5, there is no or very little compression between the horizontal part 4 and the sidewall. At this time, there is no preload or very little preload between the horizontal part 4 and the valve stem 2. Due to insufficient preload, axial force cannot be transmitted through friction or clamping force, so the valve stem 2 cannot drive the valve disc 1 to move by relying on the preload.

[0045] When the horizontal portion 4 is clamped at the lower end of the vertical sidewall of the connecting groove 5: as the horizontal portion 4 moves downward, the distance between the sidewalls of the connecting groove 5 gradually exceeds L, and the sidewalls exert a continuously increasing compressive force on the horizontal portion 4, causing the horizontal portion 4 to undergo elastic deformation and tightly adhere to the sidewalls. At this time, there is a stable preload between the horizontal portion 4 and the valve stem 2. The clamping force generated by this preload is sufficient to transmit the axial movement of the valve stem 2, so the valve stem 2 can drive the valve disc 1 to move by relying on the preload.

[0046] When the lower end of the valve stem 2 abuts against the upper side of the valve disc 1, the lower side of the horizontal part 4 and the lower side of the connecting groove 5 are spaced vertically apart, and the distance between the lower side of the horizontal part 4 and the lower side of the connecting groove 5 is 3-7mm.

[0047] Initial state: Valve disc 1 is in the closed state. When valve disc 1 is fully closed, the positions and fit of each component are as follows: the lower end of valve stem 2 is tightly abutted against the upper side of valve disc 1, and valve stem 2 presses valve disc 1 against valve seat with its own axial pressure to ensure sealing performance; the horizontal part 4 corresponds to the upper end of the vertical side wall of connecting groove 5. Since the horizontal part 4 is at the upper end of connecting groove 5, there is no pre-tightening force or the pre-tightening force between the two is very small. The force exerted by valve stem 2 on valve disc 1 is only the axial pressure of the lower end face, rather than being transmitted through the clamping force of horizontal part 4.

[0048] Opening process: Valve stem 2 moves first, then drives valve disc 1 to open. When valve disc 1 needs to be opened, valve stem 2 moves upward axially. The entire process is divided into two stages: Phase 1: Valve stem 2 moves upward independently (no-load phase) Initially, the horizontal portion 4 is located at the upper end of the connecting groove 5, and there is no preload between them. When the valve stem 2 moves upward, its lower end face gradually separates from the upper side of the valve disc 1. At the same time, the horizontal portion 4 slowly slides downward along the vertical side wall of the connecting groove 5 (relative to the valve stem 2). During this stage, since no preload has been formed, the movement of the valve stem 2 cannot drive the valve disc 1, and the valve disc 1 remains closed until the lower side of the horizontal portion 4 abuts against the lower side of the connecting groove 5, at which point the idle stroke ends.

[0049] Second stage: Valve stem 2 drives valve disc 1 to open upwards. After the horizontal portion 4 abuts against the lower side of the connecting groove 5, the valve stem 2 continues to move upward. At this time, the horizontal portion 4 is confined to the lower end area of ​​the connecting groove 5. Since the distance between the lower side walls of the connecting groove 5 is greater than L, a stable preload is formed between the horizontal portion 4 and the side walls. The clamping force generated by the preload fixes the valve stem 2 and the valve disc 1 relatively. Subsequently, the upward movement of the valve stem 2 is transmitted to the valve disc 1 through the preload, causing the valve disc 1 to move upward along the valve body guide rail. The valve disc 1 gradually separates from the valve seat, and the valve opens. (Alternatively, before the horizontal portion 4 abuts against the lower side of the connecting groove 5, a sufficiently large preload has already been formed, and the valve stem 2 can also drive the valve disc to move upward to open the valve.)

[0050] Closing process: Valve stem 2 moves valve disc 1, then valve stem 2 moves downward independently. When it is necessary to close valve disc 1, valve stem 2 moves axially downwards, a process that also consists of two stages: Phase 1: Valve stem 2 drives valve disc 1 to move downwards. With the valve open, the horizontal part 4 is located at the lower end of the connecting groove 5, and a preload is maintained between them. The valve stem 2 and the valve disc 1 are relatively fixed by the preload. Therefore, when the valve stem 2 moves downward, the preload directly drives the valve disc 1 to move downward along the valve body guide rail. The valve disc 1 gradually approaches the valve seat until the sealing surface of the valve disc 1 is in complete contact with the valve seat, at which point the valve disc 1 can no longer move downward, and this stage ends.

[0051] Second stage: Valve stem 2 moves downward independently to complete the sealing and tightening. After valve disc 1 contacts the valve seat and stops moving, valve stem 2 continues to move downward under the operating force. Since valve disc 1 is stationary, the horizontal part 4 slides upward relative to valve stem 2, gradually moving from the lower end of connecting groove 5 to the upper end position. The preload gradually disappears as the horizontal part 4 moves upward. Until the lower end face of valve stem 2 abuts against the upper side of valve disc 1 again, valve stem 2 stops moving. At this time, the axial pressure of the lower end face of valve stem 2 presses valve disc 1 tightly against the valve seat, ensuring a tight valve seal and completing the closing action.

[0052] In actual operation, the movement of valve disc 1 and valve stem 2 is affected by fluid pressure. When opening and closing the valve disc, the valve disc may move towards the valve stem under the action of fluid pressure, so that the lower end of valve stem 2 is kept in a state of contact with the upper side of valve disc 1.

[0053] In the vertical direction, the width of the connecting groove 5 is greater than the thickness of the horizontal portion 4. The core design purpose of this dimensional difference is to provide vertical movement space for the horizontal portion 4 within the connecting groove 5.

[0054] The lower side of valve disc 1 forms a sealing surface that mates with the valve seat. This sealing surface is the core functional area for valve disc 1 to achieve valve sealing.

[0055] The clamping part and the valve disc 1 are integrated. This design makes the clamping part and the valve disc 1 form a unified force-bearing unit, eliminating assembly gaps or weak points in the connection that would occur with separate parts.

[0056] The upper end of the valve stem 2 is provided with an external thread 7. This external thread 7 is the connecting component between the valve stem 2 and the valve operating mechanism (such as a handwheel or electric actuator).

[0057] In the front-to-back direction, the width of the clamping part is greater than the diameter of the valve stem 2. This dimensional relationship ensures that the valve stem 2 can be fully accommodated between the left and right clamping parts.

[0058] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A novel valve stem and valve disc connection structure for a pilot-operated shut-off valve, comprising a valve disc and a valve stem, characterized in that: The valve disc has symmetrical clamping parts on the left and right sides of its upper side. Each clamping part includes an upwardly extending vertical part and a horizontal part extending towards the center of the valve disc. The two horizontal parts are spaced apart. The valve stem is connected between the two clamping parts. The valve stem has connecting grooves on its left and right sides that pass through the front and rear sides of the valve stem. The horizontal parts extend into the connecting grooves and clamp onto the valve stem.

2. The valve stem and valve disc connection structure of a novel pilot-operated shut-off valve according to claim 1, characterized in that: The valve disc is provided with guide grooves that run through its upper and lower sides on its front and rear sides respectively.

3. The valve stem and valve disc connection structure of a novel pilot-operated shut-off valve according to claim 2, characterized in that: The distance between the vertical sidewalls of the two connecting grooves gradually increases from top to bottom; in the natural state, the distance between the two horizontal parts is L, which is greater than or equal to the distance between the upper ends of the vertical sidewalls of the two connecting grooves, and less than the distance between the lower ends of the vertical sidewalls of the two connecting grooves.

4. The valve stem and valve disc connection structure of a novel pilot-operated shut-off valve according to claim 3, characterized in that: When the lower end of the valve stem abuts against the upper side of the valve disc, the lower side of the horizontal part and the lower side of the connecting groove are spaced vertically apart.

5. The valve stem and valve disc connection structure of a novel pilot-operated shut-off valve according to claim 4, characterized in that: When the lower end of the valve stem abuts against the upper side of the valve disc, the distance between the lower side of the horizontal part and the lower side of the connecting groove is 3-7mm.

6. The valve stem and valve disc connection structure of a novel pilot-operated shut-off valve according to claim 3, characterized in that: In the vertical direction, the width of the connecting groove is greater than the thickness of the horizontal portion.

7. The valve stem and valve disc connection structure of a novel pilot-operated shut-off valve according to claim 1, characterized in that: The lower side of the valve disc forms a sealing surface that mates with the valve seat.

8. The valve stem and valve disc connection structure of a novel pilot-operated shut-off valve according to claim 1, characterized in that: The clamping part and the valve disc are integrally formed.

9. The valve stem and valve disc connection structure of a novel pilot-operated shut-off valve according to claim 1, characterized in that: The upper end of the valve stem is provided with an external thread.

10. The valve stem and valve disc connection structure of a novel pilot-operated shut-off valve according to claim 1, characterized in that: In the front-to-back direction, the width of the clamping part is greater than the diameter of the valve stem.

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