A PFA pipe fitting leak-proof sealing structure

Abstract

The utility model discloses a kind of PFA pipe fittings leak-proof sealing structure, the utility model relates to PFA pipe fittings sealing technical field, including fixed pipe and the two PFA pipes that are symmetrically distributed and inserted in fixed pipe inside, the inside of fixed pipe is provided with protruding ring, the left and right sides of protruding ring are equipped with sealing ring, the outside of fixed pipe is equipped with sealing structure, the utility model has the advantages that: first sealing is formed by protruding ring inside fixed pipe and two sides sealing ring, and the filling ring in fixed sleeve cavity is further filled sealing gap, when cooperation moving ring is screwed, its horn shape opening extrusion abutment block, drive abutment rod drives abutment ring and compacts filling ring to realize multiple sealing, and elastic plastic locking ring is gathered to middle portion under the action of moving ring, additional sealing guarantee is formed by closely adhering inner wall rubber pad and fixed pipe outer wall, simultaneously, moving ring is effectively limited moving ring reverse loosening by the meshing connection of ratchet and fixed sleeve outside ratchet tooth.

Description

Technical Field

[0001] This utility model relates to the field of PFA pipe fitting sealing technology, specifically a leak-proof sealing structure for PFA pipe fittings. Background Technology

[0002] In fields such as semiconductors, pharmaceuticals, fine chemicals, and photovoltaics, where the purity and sealing requirements of fluid transportation are stringent, PFA (perfluoroalkoxyalkane) fittings have become core components of high-purity fluid (such as semiconductor photoresist, electronic specialty gases, pharmaceutical sterile water, and chemical corrosive reagents) transmission systems due to their extreme corrosion resistance (resistance to most chemical media such as strong acids, strong alkalis, and strong oxidants), ultra-high cleanliness (no precipitates, smooth inner walls that do not adsorb impurities), and wide temperature range (-200℃~260℃). Among these, the sealing performance of the connection between two PFA fittings directly determines the stability of the system. Once a leak occurs, it may not only lead to the waste of high-value liquids and deviations in experimental data, but may also cause serious consequences such as semiconductor wafer contamination, chemical corrosion accidents, and destruction of the pharmaceutical sterile environment. Therefore, the reliability of the sealing structure is a key requirement for the application of PFA fittings.

[0003] Existing PFA pipe fitting leak-proof sealing structures mostly adopt single-ring compression seals or simple threaded connections. Among them, single-ring seals have limited contact area with the inner wall of the PFA pipe fitting, resulting in uneven sealing pressure distribution. Under high pressure and temperature cycling conditions, they are prone to elastic decay due to ring stress fatigue, which leads to the formation of micro-gaps in the seal. On the other hand, some threaded connection structures lack anti-loosening and limiting designs, and the thermal expansion coefficients of PFA material and matching metal fittings are significantly different. When the equipment vibrates or the temperature fluctuates, the nut is prone to loosening and displacement, further expanding the sealing gap, and ultimately causing sealing failure problems such as media penetration and dripping. Therefore, we propose a leak-proof sealing structure for PFA pipe fittings. Utility Model Content

[0004] The purpose of this invention is to provide a leak-proof sealing structure for PFA pipe fittings.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a PFA pipe fitting anti-leakage sealing structure, comprising a fixed pipe and two symmetrically distributed PFA pipes inserted into the fixed pipe, wherein a raised ring is provided inside the fixed pipe, sealing rings are installed on the left and right sides of the raised ring, and a sealing structure is assembled on the outside of the fixed pipe. The sealing structure includes fixed sleeves fixedly installed on the left and right sides of the fixed tube and cavities opened in the inner walls of the fixed sleeves. The cavity is equipped with a filling ring. Limiting rings are installed on the side of the two fixed sleeves that are away from each other. The external threads of the limiting rings are connected to a movable ring.

[0006] As a further embodiment of this utility model: a sliding groove is provided on the inner wall of the cavity, and an abutment rod is slidably connected to the inner wall of the sliding groove.

[0007] As a further embodiment of this utility model: one end of the abutting rod is fixedly connected to an abutting ring, the other end of the abutting rod is fixedly connected to an abutting block, and one end of the moving ring is a funnel-shaped opening that narrows inward.

[0008] As a further embodiment of this utility model: a locking ring is fixedly connected to one end of the limiting ring away from the fixing sleeve. The locking ring is an elastic plastic part, and the locking ring can converge towards the center when subjected to external pressure.

[0009] As a further embodiment of this utility model: a rubber pad is installed on the inner wall of the locking ring, and the rubber pad is used to contact the outer wall of the fixing tube.

[0010] As a further embodiment of this utility model: a pawl is rotatably connected inside the moving ring, and a spring is assembled between the pawl and the moving ring, the spring being used to drive the pawl to reset.

[0011] As a further embodiment of this utility model: the outer side of the fixed sleeve is provided with ratchet teeth that are adapted to the pawl, the pawl is engaged with the ratchet teeth, and the pawl maintains an engagement relationship with the ratchet teeth when it moves with the moving ring.

[0012] Compared with the prior art, the beneficial effects of this utility model by adopting the above technical solution are as follows: This invention forms a first seal through the raised ring inside the fixed tube and the sealing rings on both sides. The filling ring inside the cavity of the fixed sleeve further fills the sealing gap. When the moving ring is tightened, its flared opening squeezes the abutment block, driving the abutment rod to move the abutment ring to press the filling ring, thus achieving multiple seals. The elastic plastic locking ring is brought together towards the center under the action of the moving ring, and the inner wall rubber pad fits tightly against the outer wall of the fixed tube to form an additional sealing guarantee. At the same time, the moving ring is effectively restricted from loosening in the reverse direction by the engagement of the pawl and the ratchet teeth on the outside of the fixed sleeve to ensure stable sealing pressure. The overall structure has high sealing reliability, can be assembled and locked without complicated tools, and can adapt to the sealing requirements under different working conditions.

[0013] Other advantages, objectives and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be taught from the practice of this invention. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2This is a schematic diagram of the limiting ring and locking ring structure in this utility model; Figure 3 This is a schematic cross-sectional view of the entire utility model. Figure 4 This is a schematic diagram of the overall three-dimensional cross-sectional structure of this utility model; Figure 5 for Figure 1 Enlarged diagram of point A in the middle.

[0015] In the diagram: 1. Fixed tube; 2. PFA tube; 3. Raised ring; 4. Sealing ring; 5. Sealing structure; 51. Fixed sleeve; 52. Filler ring; 53. Limiting ring; 54. Moving ring; 55. Abutment rod; 56. Abutment ring; 57. Locking ring; 58. Pawl; 59. Spring. Detailed Implementation

[0016] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings. It should be noted that the description of these embodiments is for the purpose of helping to understand this utility model, but does not constitute a limitation on this utility model.

[0017] Furthermore, the technical features involved in the various embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0018] Please see the appendix Figure 1 - Appendix Figure 5 This utility model discloses a leak-proof sealing structure for PFA pipe fittings, including a fixed pipe 1 and two symmetrically distributed PFA pipes 2 inserted inside the fixed pipe 1. The fixed pipe 1 has a raised ring 3 inside and is made of engineering plastic. Sealing rings 4 are installed on the left and right sides of the raised ring 3. The sealing rings 4 are adapted to the chemical properties and working temperature of the PFA pipe. Their initial outer diameter is slightly larger than the outer diameter of the groove. After assembly, a primary seal is achieved through pre-compression. When the PFA pipe 2 is inserted into place, its end face fits tightly with the sealing ring 4, forming the first line of defense to prevent the medium from leaking from the gap between the pipes. A sealing structure 5 is installed on the outside of the fixed pipe 1. The axis of the raised ring 3 coincides with the axis of the fixed pipe 1, which is used to axially limit the PFA pipes 2 on both sides to avoid excessive insertion or misalignment, and at the same time provide an installation surface for the sealing rings 4. The sealing structure 5 includes a fixed sleeve 51 fixedly installed on the left and right sides of the fixed pipe 1 and a cavity opened in the inner wall of the fixed sleeve 51. The cavity is equipped with a filling ring 52. The filling ring 52 is concave and will deform when squeezed by the abutment ring. It will fit tightly against the inner wall of the fixed sleeve 51 and the outer wall of the PFA pipe 2 to form a second seal and make up for the minor gaps in the basic seal. A limit ring 53 is installed on the side of the two fixed sleeves 51 that is away from each other. The external thread of the limit ring 53 is connected to a moving ring 54.

[0019] Specifically, this utility model addresses the shortcomings of existing PFA pipe fitting sealing structures, which are prone to elastic decay of the ring seal and loosening of the threaded connection, leading to failure and leakage under complex working conditions. Therefore, a first seal is formed by the raised ring 3 inside the fixed pipe 1 and the sealing rings 4 on both sides. The filling ring 52 inside the cavity of the fixed sleeve 51 further fills the sealing gap. When the moving ring 54 is tightened, its flared opening presses against the abutment block, driving the abutment rod 55 to move the abutment ring 56 to press the filling ring 52, achieving multiple seals. The elastic plastic locking ring 57, under the action of the moving ring 54, converges towards the center, forming an additional seal through a tight fit between the inner wall rubber pad and the outer wall of the fixed pipe 1. Simultaneously, the moving ring 54, through the engagement of the pawl 58 with the external ratchet teeth of the fixed sleeve 51, effectively restricts the reverse loosening of the moving ring 54 to ensure stable sealing pressure. The overall structure boasts high sealing reliability, requiring no complex tools for assembly and tightening, and can adapt to sealing requirements under different working conditions.

[0020] The inner wall of the cavity is provided with a sliding groove, the length of which is adapted to the axial length of the cavity. This groove is used to guide the sliding direction of the abutment rod 55 and ensure that the abutment rod 55 can only move along the axis of the fixed sleeve 51. The abutment rod 55 is slidably connected to the inner wall of the sliding groove. One end of the abutment rod 55 is fixedly connected to an abutment ring 56, and the other end of the abutment rod 55 is fixedly connected to an abutment block. One end of the moving ring 54 is a flared opening that narrows inward. The end of the limiting ring 53 away from the fixed sleeve 51 is fixedly connected to a locking ring 57. The locking ring 57 is an elastic plastic part that can converge towards the center when the locking ring 57 is squeezed externally. Specifically, when the moving ring 54 moves to the end in the direction of the limiting ring 53, its inner wall will generate radial extrusion force on the outer wall of the locking ring 57, causing the locking ring 57 to converge towards the center, and driving the rubber pad to tightly adhere to the outer wall of the PFA pipe 2, forming a third seal and axial locking.

[0021] A rubber pad is installed on the inner wall of the locking ring 57. The rubber pad is used to contact the outer wall of the fixed tube 1. A pawl 58 is rotatably connected inside the moving ring 54. A spring 59 is assembled between the pawl 58 and the moving ring 54. The spring 59 is used to drive the pawl 58 to reset. A ratchet tooth that matches the pawl 58 is opened on the outside of the fixed sleeve 51. The pawl 58 is engaged with the ratchet tooth. The pawl 58 maintains an engagement relationship with the ratchet tooth when it moves with the moving ring 54. Specifically, the middle of each pawl 58 is rotatably connected to the moving ring 54 via a pin, allowing the pawl 58 to swing around the pin at a small angle. One end of the pawl 58 is the engagement end, which is adapted to the ratchet teeth on the outside of the fixed sleeve 51, and the other end abuts against the spring 59. The spring 59 is a torsion spring or a compression spring. In its natural state, it pushes the engagement end of the pawl 58 to engage tightly with the ratchet teeth. When the moving ring 54 is rotated clockwise (tightening direction), the engagement end of the pawl 58 slides along the inclined surface of the ratchet teeth. The spring 59 is compressed and reset, ensuring continuous engagement. At this time, the moving ring 54 can move towards the fixed sleeve 51, pushing the abutment component to squeeze the filling ring 52. When attempting to rotate the moving ring 54 counterclockwise (loosening direction), the engagement end of the pawl 58 makes rigid contact with the straight surface of the ratchet teeth. The elasticity of the spring 59 makes the engagement tighter, preventing the moving ring 54 from reversing, realizing the one-way locking function, avoiding the loosening of the sealing structure due to vibration under working conditions, and ensuring sealing stability.

[0022] Working principle: First, align the two PFA tubes 2 to be connected with the openings at both ends of the fixed tube 1 and insert them into the fixed tube 1 until the end face of the PFA tube 2 is tightly fitted with the sealing rings 4 on both sides of the protruding ring 3 inside the fixed tube 1. The initial seal is completed by the pre-compression deformation of the sealing rings 4. At the same time, the axial limiting effect of the protruding ring 3 ensures that the two PFA tubes 2 are in a coaxial state. Then, hold the moving ring 54 with both hands and rotate it clockwise. The moving ring 54 moves towards the fixed sleeve 51 along the external thread of the limiting ring 53. Its flared opening will squeeze the locking ring 57. The locking ring 57 and the rubber pad will converge towards the center and clamp and fix the outer wall of the PFA tube 2. When they converge towards the center, the rubber pads will abut against each other and increase the pressure. To enhance the sealing effect, when the moving ring 54 rotates, it will drive the abutment ring 56 and abutment rod 55 to move. At this time, the abutment rod 55 will squeeze the filling ring 52 through the abutment block. The concave filling ring 52 will undergo radial deformation after being squeezed, tightly fitting the inner wall of the fixed sleeve 51 and the outer wall of the PFA pipe 2, forming a second seal, effectively compensating for the small gap between the pipe body and the fixed sleeve 51. At this time, the pawl 58 inside the moving ring 54 will engage unidirectionally with the ratchet teeth outside the fixed sleeve 51 under the action of the spring 59, preventing the moving ring 54 from loosening in the opposite direction due to vibration or temperature changes, ensuring stable sealing pressure. The sealed pipe fitting can then be connected to the pipeline system and put into operation. Thus, the entire process is completed.

[0023] The terms "front," "back," "left," "right," "top," and "bottom" all refer to the figures in the accompanying drawings. Figure 1 Based on.

[0024] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this utility model.

[0025] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments.

[0026] For those skilled in the art, various changes, modifications, substitutions, and alterations to these embodiments without departing from the principles and spirit of this utility model will still fall within the protection scope of this utility model.

Claims

1. A leak-proof sealing structure for PFA pipe fittings, comprising a fixed pipe (1) and two symmetrically distributed PFA pipes (2) inserted inside the fixed pipe (1), characterized in that: The fixed tube (1) is provided with a raised ring (3) inside, and sealing rings (4) are installed on the left and right sides of the raised ring (3). The fixed tube (1) is equipped with a sealing structure (5) on the outside. The sealing structure (5) includes a fixed sleeve (51) fixedly installed on the left and right sides of the fixed tube (1) and a cavity opened in the inner wall of the fixed sleeve (51). The cavity is equipped with a filling ring (52). A limiting ring (53) is installed on the side of the two fixed sleeves (51) that is away from each other. A moving ring (54) is threadedly connected to the outside of the limiting ring (53).

2. The leak-proof sealing structure for PFA pipe fittings according to claim 1, characterized in that: The inner wall of the cavity is provided with a sliding groove, and an abutment rod (55) is slidably connected to the inner wall of the sliding groove.

3. The leak-proof sealing structure for PFA pipe fittings according to claim 2, characterized in that: One end of the abutting rod (55) is fixedly connected to an abutting ring (56), and the other end of the abutting rod (55) is fixedly connected to an abutting block. One end of the moving ring (54) is a horn-shaped opening that narrows inward.

4. The leak-proof sealing structure for PFA pipe fittings according to claim 3, characterized in that: The limiting ring (53) is fixedly connected to a locking ring (57) at one end away from the fixing sleeve (51). The locking ring (57) is an elastic plastic part, and the locking ring (57) can converge towards the center when it is squeezed by the outside.

5. The leak-proof sealing structure for PFA pipe fittings according to claim 4, characterized in that: The inner wall of the locking ring (57) is fitted with a rubber pad, which is used to contact the outer wall of the fixing tube (1).

6. The leak-proof sealing structure for PFA pipe fittings according to claim 5, characterized in that: The movable ring (54) is rotatably connected to a pawl (58), and a spring (59) is fitted between the pawl (58) and the movable ring (54). The spring (59) is used to drive the pawl (58) to reset.

7. The leak-proof sealing structure for PFA pipe fittings according to claim 6, characterized in that: The fixed sleeve (51) has ratchet teeth that are adapted to the pawl (58) on its outside. The pawl (58) is engaged with the ratchet teeth and maintains an engagement relationship with the ratchet teeth when the pawl (58) moves with the moving ring (54).

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