Small-bore high-pressure corrugated pipe safety valve

Abstract

The utility model discloses a small caliber high pressure bellows safety valve relates to safety valve technical field, solves the failure problem such as small size valve stem bending easily, the valve piece includes the valve piece of the integral constitution and the recoil disc part, and the lower extreme of bellows is connected with the recoil disc part, the top side of valve piece forms the guide column upwards and extends, and the guide hole of guide bushing slides up and down with the guide column, and the top end of guide column extends to the top hole orifice position of guide hole, and the lower spring seat is equipped with below spring, and the bottom of valve rod is abutted with lower spring seat, and the bottom surface of lower spring seat has the first cone body of the downward convex inverted cone, and the top surface of guide column is equipped with the first taper groove of the first cone body adaptation, and the first cone body is formed positioning into the first taper groove. The overall structural strength and rigidity of valve rod system are strengthened, can bear the high load under the high pressure working condition of small caliber, and the length of guide cooperation is prolonged, and the perpendicularity and stability of valve piece in the movement in the opening and closing process are ensured.

Description

Technical Field

[0001] This utility model relates to the field of safety valve technology, and in particular to a small-diameter high-pressure bellows safety valve. Background Technology

[0002] Bellows safety valves are important safety pressure relief devices widely used in high-pressure conditions. Their bellows structure effectively balances back pressure, prevents media leakage, and improves sealing performance. Various bellows safety valve structures exist in the prior art, such as the anti-chatter bellows safety valve with patent publication number CN219549700U. This valve includes components such as a valve body, valve seat, valve cover, guide sleeve, backflushing disc, valve disc, valve stem, and spring, with a bellows installed between the guide sleeve and the backflushing disc. The upper and lower ends of the bellows are connected to the guide sleeve and the backflushing disc respectively via mounting seats. This structure, through bellows compensation and anti-vibration design, improves the valve's sealing performance and anti-chatter capabilities to a certain extent.

[0003] However, in applications involving small-diameter high-pressure safety valves, the bellows structure used in CN219549700U still has significant drawbacks. Because the bellows installation occupies radial space between the guide sleeve and the backflush plate, and the internal assembly space of the small-diameter safety valve itself is limited, the guide portion of the guide sleeve is forced to be significantly reduced in size. This reduction in guide portion size directly results in a much smaller bottom structure for the valve stem, which severely weakens the mechanical strength of the valve stem head. Under high-pressure conditions, the valve stem must withstand multiple loads, including spring preload and media impact force. The insufficient strength of the valve stem bottom end makes it difficult to withstand these loads, easily leading to bending, breakage, and other failures. This fails to meet the pressure requirements of small-diameter high-pressure safety valves, posing a threat to equipment safety. Utility Model Content

[0004] The purpose of this utility model is to overcome the defects of the prior art and provide a small-diameter high-pressure bellows safety valve to solve the problem of small-sized valve stems being prone to bending, breakage and other failures.

[0005] The technical solution of this utility model includes a valve disc, a valve body, a valve cover, a guide sleeve, a valve stem, a spring, and a bellows. The guide sleeve is disposed between the valve body and the valve cover. The upper end of the bellows is connected to the guide sleeve. The valve stem is disposed inside the valve cover. The spring is mounted on the valve stem. A guide hole is provided inside the guide sleeve. The valve disc includes an integrally formed valve disc part and a backflush disc part. The lower end of the bellows is connected to the backflush disc part. A guide post extends upward from the top side of the valve disc to form a guide post. The guide post slides up and down with the guide hole of the guide sleeve, and the top end of the guide post extends to the top opening of the guide hole. A lower spring seat is provided below the spring. The lower spring seat abuts against the bottom end of the valve stem. The bottom surface of the lower spring seat has a downwardly protruding inverted conical first cone. The top surface of the guide post has a first conical groove that matches the first cone. The first cone extends into the first conical groove to form a positioning.

[0006] By adopting the above technical solution, the valve disc and the backflush disc are integrated into a single valve disc component, and a guide post extends upward to cooperate with the guide sleeve. This eliminates the small weak link at the connection between the valve stem and the backflush disc in the original split structure, enhancing the overall structural strength and rigidity of the valve stem, enabling it to withstand high loads under small-diameter, high-pressure conditions. The guide post extends directly to the top of the guide hole, extending the length of the guide fit and ensuring the verticality and stability of the valve disc component's movement during opening and closing. This effectively prevents lateral wear and jamming, improving the alignment and sealing reliability of the sealing pair. In addition, the inverted conical first cone of the lower spring seat and the first conical groove of the guide post form a conical surface positioning fit, which can automatically align and effectively counteract the rotational torque generated when the spring is compressed or extended. This ensures that the spring force is always transmitted vertically to the valve disc component, preventing the valve disc component from being offset by lateral force components. This ensures that the valve disc part and the valve seat sealing surface are uniformly fitted, and at the same time solves the problem of spring rotation affecting the valve stem force in the prior art, indirectly improving the valve stem's load-bearing capacity.

[0007] In one possible design, the lower spring seat is a hollow box-shaped structure, with the bottom end of the valve stem extending downward into the inner cavity of the lower spring seat. The bottom end of the valve stem is fitted with a fastener, which is screwed to the lower spring seat and covers the inner cavity opening of the lower spring seat. The fastener abuts against the outer edge of the bottom end of the valve stem.

[0008] With the above design, the lower spring seat adopts a hollow box structure, providing an independent movable inner cavity for the bottom end of the valve stem, and reserving space for the valve stem to make small displacements under high pressure conditions. Through the structure of the fastener abutting against the outer edge of the bottom end of the valve stem, the axial positioning of the valve stem and the lower spring seat is realized, and the stress transmission caused by the rigid connection is avoided. When the spring rotates, the rotational force of the lower spring seat will not be directly transmitted to the valve stem, ensuring the stability of the valve stem under force.

[0009] In one possible design, the bottom end of the valve stem has a downwardly protruding inverted conical second truncated cone, and the bottom of the inner cavity of the lower spring seat has a second conical groove that matches the second truncated cone. The second truncated cone extends into the second conical groove to form a positioning fit.

[0010] The above design forms a secondary conical surface positioning, which realizes secondary positioning and automatic centering between the valve stem and the lower spring seat. This further restricts the relative rotation between the valve stem and the lower spring seat. The double conical surface positioning ensures that the valve stem is always in an axially aligned state, avoiding valve stem skewing caused by spring rotation or medium impact, and ensuring that the valve stem is subjected to vertical force. Structurally, this solves the problem of insufficient strength of the valve stem caused by force deviation in the prior art, and improves the bending and fracture resistance of the valve stem under high pressure.

[0011] In one possible design, the apex angle of the first frustum is smaller than the apex angle of the first conical groove, and the apex angle of the second frustum is smaller than the apex angle of the second conical groove.

[0012] The above design allows the frustum and the conical groove to form a small-area contact fit, reserving assembly and motion compensation gaps. This structure allows the frustum to make minor adaptive adjustments within the conical groove, which can offset the machining errors or assembly deviations of the guide sleeve and guide post, avoid jamming of the conical surface fit, and at the same time, still effectively achieve radial positioning and automatic centering, ensuring structural stability.

[0013] In one possible design, the guide post and the guide hole of the guide sleeve are clearance fit.

[0014] The above design reduces the frictional resistance when the two slide relative to each other, ensuring smooth movement of the valve disc during the opening and closing of the safety valve and avoiding pressure relief delay or sealing failure caused by friction jamming.

[0015] In one possible design, the fastener and valve stem have a clearance fit.

[0016] The above design ensures that the valve stem is not restricted by fasteners during axial movement or minor radial adjustment, and avoids additional torque on the valve stem caused by the rotation of the lower spring seat. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a specific embodiment of the present utility model;

[0018] Figure 2 This utility model Figure 1 A magnified view of a section at point A in the middle;

[0019] Among them, 1. Valve disc; 11. Valve disc part; 12. Backflush disc part; 13. Guide post; 131. First conical groove; 2. Guide sleeve; 3. Spring; 31. Lower spring seat; 32. First cone; 33. Second conical groove; 4. Valve stem; 41. Fastener; 42. Second cone; 5. Bellows; 6. Valve body; 7. Valve cover. Detailed Implementation

[0020] like Figure 1 , Figure 2 The small-diameter high-pressure bellows safety valve shown mainly comprises a valve body 6, a valve cover 7, a guide sleeve 2, a valve stem 4, a spring 3, a bellows 5, a valve disc 1, and a lower spring seat 3. The guide sleeve 2 is fixedly disposed between the valve body 6 and the valve cover 7, forming a through-hole for installation and guidance. The upper end of the bellows 5 is fixedly connected to the guide sleeve 2, and the lower end is connected to the valve disc 1. The expansion and contraction of the bellows 5 achieves media isolation and motion compensation. The valve stem 4 passes through the inside of the valve cover 7, and its lower end cooperates with the lower spring seat 3. The spring 3 is fitted onto the valve stem 4, providing pre-tightening force to the sealing structure through elastic force under normal conditions.

[0021] The valve disc component 1 is manufactured using an integrated molding process. Its lower part is a valve disc portion 11 that fits the valve seat, and its upper part is a disc-shaped recoil plate portion 12. The valve disc portion 11 and the recoil plate portion 12 are integrally connected, improving the overall structural strength and enabling it to directly withstand the impact load of high-pressure media. The top side of the recoil plate portion 12 extends upward to form a columnar guide post 13. This guide post 13 forms an upward sliding fit with the guide hole opened inside the guide sleeve 2. In the assembled state, the guide post 13 inserts upward into the guide hole, and its top end extends to or very close to the top opening of the guide hole, thereby achieving the maximum guide length. This ensures that the guide fit length covers the entire axial height of the guide sleeve 2, improving the guiding accuracy of the valve disc component 1 during movement.

[0022] The guide post 13 and the guide hole of the guide sleeve 2 are fitted with a clearance fit. The size of the clearance is set according to the diameter and working pressure of the safety valve. The clearance fit reduces the frictional resistance when the two move relative to each other, ensuring smooth opening and closing of the valve disc 1. It also provides compensation space for the thermal expansion and contraction of the guide post 13 under high pressure and high temperature conditions, thus avoiding jamming.

[0023] Below the spring 3 is a lower spring seat 3, which is a hollow box-shaped structure with an internal cavity. Its external contour matches the lower end face of the spring 3, stably bearing the elastic pressure of the spring 3. The bottom surface of the lower spring seat 3 is integrally formed with a downwardly protruding inverted conical first cone 32. Correspondingly, the top surface of the guide post 13 has a first conical groove 131 that matches the shape of the first cone 32. During assembly, the first cone 32 extends into the first conical groove 131 to form a conical positioning fit. To achieve self-adjustment, the angle of the cone tip of the first cone 32 is smaller than the angle of the cone tip of the first conical groove 131, with a small angle difference gap between them. This conical fit structure has an automatic centering function, ensuring that the downward force point of the spring 3 always coincides with the axis of the guide post 13, thereby vertically transmitting the force of the spring 3 to the valve disc 1. This effectively prevents the generation of lateral force due to possible rotation of the spring 3, ensuring the reliability of the valve seal.

[0024] The bottom end of the valve stem 4 extends downward into the inner cavity of the lower spring seat 3. Its end is integrally formed with a downward-protruding inverted conical second truncated cone 42. The bottom of the inner cavity of the lower spring seat 3 has a second conical groove 33 that matches the second truncated cone 42. The second truncated cone 42 extends into the second conical groove 33, forming a secondary conical surface for positioning. Similar to the first conical surface, the apex angle of the second truncated cone 42 is smaller than the apex angle of the second conical groove 33. This double conical surface positioning structure restricts the relative rotation between the valve stem 4 and the lower spring seat 3, ensuring that they always remain axially aligned.

[0025] The top opening of the lower spring seat 3 is provided with an internal thread. The fastener 41 adopts a nut structure, and its external thread is adapted to the internal thread of the lower spring seat 3. It is fixed to the top of the lower spring seat 3 by screwing, covering the inner cavity opening. The inner diameter of the fastener 41 is slightly larger than the outer diameter of the valve stem 4, forming a clearance fit between the two. The lower end face of the fastener 41 abuts against the outer edge step of the bottom end of the valve stem 4, which not only achieves axial positioning of the valve stem 4 and the lower spring seat 3, but also avoids stress transmission caused by rigid connection.

[0026] The working principle of the safety valve in this application is as follows: Under normal conditions, spring 3 is in a compressed state, and its elastic force is transmitted to guide post 13 through lower spring 3 seat, thereby pushing valve disc 1 to move downward, so that valve disc 11 fits tightly with valve seat, achieving the sealing of safety valve. At this time, the double conical positioning structure ensures that valve stem 4, lower spring 3 seat and guide post 13 remain axially aligned, and valve stem 4 only bears axial pressure without additional radial stress.

[0027] When the system pressure exceeds the set value, the medium pressure acts on the bottom surface of the valve disc 1, overcoming the elastic force of the spring 3 and pushing the valve disc 1 upward. The guide post 13 slides smoothly along the guide hole of the guide sleeve 2, and the valve disc part 11 disengages from the valve seat. The medium enters the valve body 6 through the gap between the valve seat and the valve disc part 11 and is depressurized. During this process, the bellows 5 is stretched as the valve disc 1 moves upward, and at the same time, the lower spring 3 seat moves upward synchronously with the guide post 13, and the spring 3 is further compressed. Since the conical surfaces of the first cone 32 and the first conical groove 131, and the second cone 42 and the second conical groove 33 have automatic centering, and the clearance fit reduces the movement resistance, the additional torque generated by the rotation of the spring 3 can be effectively avoided from affecting the movement posture of the valve stem 4 and the valve disc 1, ensuring the stability of the depressurization process.

[0028] When the system pressure drops below the set value, the elastic force of spring 3 pushes the spring 3 seat and guide post 13 downward to reset, and the valve disc 11 re-fits the valve seat, restoring the safety valve to a sealed state. The double-cone positioning structure guides the valve disc 1 to accurately reset during this process, ensuring uniform contact of the sealing surface and improving sealing reliability.

Claims

1. A small-diameter high-pressure bellows safety valve, comprising a valve body (6), a valve cover (7), a guide sleeve (2), a valve stem (4), a spring (3), and a bellows (5), wherein the guide sleeve (2) is disposed between the valve body (6) and the valve cover (7), the upper end of the bellows (5) is connected to the guide sleeve (2), the valve stem (4) is disposed inside the valve cover (7), the spring (3) is mounted on the valve stem (4), and a guide hole is provided inside the guide sleeve (2), characterized in that: It also includes a valve disc component (1), which includes an integrally formed valve disc part (11) and a backflush disc part (12). The lower end of the bellows (5) is connected to the backflush disc part (12). A guide post (13) extends upward from the top side of the valve disc component (1). The guide post (13) slides up and down with the guide hole of the guide sleeve (2), and the top end of the guide post (13) extends to the top opening of the guide hole. A lower spring (3) seat is provided below the spring (3). The lower spring (3) seat abuts against the bottom end of the valve stem (4). The bottom surface of the lower spring (3) seat has a downwardly protruding inverted cone-shaped first cone (32). The top surface of the guide post (13) is provided with a first cone groove (131) that matches the first cone (32). The first cone (32) extends into the first cone groove (131) to form a positioning.

2. The small-diameter high-pressure bellows safety valve according to claim 1, characterized in that: The lower spring (3) seat is a hollow box structure. The bottom end of the valve stem (4) extends downward into the inner cavity of the lower spring (3) seat. The bottom end of the valve stem (4) is fitted with a fastener (41). The fastener (41) is screwed to the lower spring (3) seat and covers the inner cavity of the lower spring (3) seat. The fastener (41) abuts against the outer edge of the bottom end of the valve stem (4).

3. The small-diameter high-pressure bellows safety valve according to claim 1, characterized in that: The bottom end of the valve stem (4) has a downward-protruding inverted conical second cone (42), and the bottom of the inner cavity of the lower spring (3) seat is provided with a second conical groove (33) that is adapted to the second cone (42). The second cone (42) extends into the second conical groove (33) to form a positioning fit.

4. The small-diameter high-pressure bellows safety valve according to claim 1 or 2, characterized in that: The apex angle of the first cone (32) is smaller than the apex angle of the first conical groove (131).

5. The small-diameter high-pressure bellows safety valve according to claim 3, characterized in that: The apex angle of the second cone (42) is smaller than the apex angle of the second cone groove (33).

6. The small-diameter high-pressure bellows safety valve according to claim 1 or 2, characterized in that: The guide post (13) and the guide hole of the guide sleeve (2) are in clearance fit.

7. The small-diameter high-pressure bellows safety valve according to claim 2, characterized in that: The fastener (41) and the valve stem (4) are in clearance fit.

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