Compression molding of pfa lined equipment
By designing a PFA compression molding liner, the mechanical interlocking and elastic deformation of the PFA liner with the metal tube solves the problem of unreliable sealing in traditional equipment under high temperature and high vacuum conditions, thus achieving long-term stable operation and improved corrosion resistance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG JINFULONG CHEM EQUIP
- Filing Date
- 2025-08-27
- Publication Date
- 2026-08-04
AI Technical Summary
Traditional equipment is prone to corrosion under high temperature and high vacuum conditions, the lining is not firmly bonded to the metal, and the flange connection is unreliable, resulting in short equipment life, seal failure and media leakage.
The PFA lining equipment uses high-temperature compression molding to create a mechanical bond between the PFA liner and the inner wall of the metal pipe. Combined with the design of the PFA corrugated ring and sealing ring cylinder, a double sealing structure is formed. By utilizing the corrosion resistance and elastic deformation characteristics of PFA, the medium is isolated and sealed from the metal.
Under high temperature and high vacuum conditions, the equipment has achieved long-term stable operation, preventing media corrosion and leakage, and improving the equipment's corrosion resistance and service life.
Smart Images
Figure CN224592883U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of chemical corrosion protection equipment technology, specifically a compression molding PFA lining equipment. Background Technology
[0002] In industries such as chemical, semiconductor, and medical, many production processes require handling corrosive media such as strong acids, strong alkalis, and strong oxidants, often accompanied by harsh operating conditions such as high temperatures (e.g., above 180°C) or high vacuum (e.g., ≥-0.095MPa). Traditional equipment often uses metal pipes or containers in direct contact with the media, or relies on simple coatings or linings (e.g., rubber, ordinary plastics) for corrosion protection, but these methods have the following problems:
[0003] 1. Metal materials are easily corroded, resulting in short equipment lifespan and frequent maintenance. Furthermore, the metal ions produced by corrosion may contaminate materials (for example, the semiconductor industry does not allow the presence of iron ions).
[0004] 2. Ordinary lining materials (such as FEP) have limited high-temperature resistance (usually ≤200℃) and are prone to aging and peeling under high-temperature conditions;
[0005] 3. Traditional linings are not tightly bonded to the metal substrate (such as by adhesive or simple bonding), and are prone to bulging and peeling due to the pressure difference between the inside and outside in a high vacuum environment, leading to sealing failure.
[0006] 4. The sealing structure design of flanges and other connection parts is unreasonable, which can easily lead to media leakage. Moreover, when metal flanges are in direct contact with the media, the corrosion rate is fast, which affects the safety and stability of the overall equipment. Therefore, a compression molding PFA lining equipment is proposed to solve the above-mentioned industry pain points. Utility Model Content
[0007] The purpose of this invention is to provide a compression molding PFA lining equipment to solve the problems mentioned in the background art, such as insufficient corrosion resistance of traditional equipment, weak bonding between the lining and the metal, easy failure under high temperature and high vacuum conditions, and unreliable sealing of flange connection parts.
[0008] To achieve the above objectives, this utility model provides the following technical solution:
[0009] A compression molding PFA lining device includes a metal tube with a first flange and a second flange respectively connected to both ends of the metal tube. The first flange can be bolted to the second flange on another set of the metal tubes. A sealing mechanism is formed inside the metal tube by high-temperature compression molding.
[0010] In the aforementioned compression molding PFA lining equipment, the sealing mechanism includes a PFA bushing. The PFA bushing, in a molten state, is filled into a dovetail groove on the inner wall of the metal tube by pressure and directly adheres to the metal surface of the metal tube.
[0011] In the aforementioned compression molding PFA lining equipment, one end of the PFA liner is fixedly connected to a PFA corrugated ring, which is located within the inner ring diameter range of the first flange.
[0012] In the aforementioned compression molding PFA lining equipment, a sealing ring cylinder is extended from one end of the second flange. During the splicing process between the second flange and the first flange, the second flange can drive the sealing ring cylinder to insert into the inner ring diameter of the first flange and exert a top pressure on the PFA bellows, causing the PFA bellows to collapse inward.
[0013] In the aforementioned compression molding PFA lining equipment, when the PFA corrugated ring is compressed and collapses inward, its corrugated structure undergoes elastic deformation. This elastic deformation can tightly fill the gap between the sealing ring cylinder and the second flange, forming a dual protection structure of "physical compression sealing + material corrosion-resistant barrier".
[0014] In the aforementioned compression molding PFA lining equipment, a PFA sealing gasket is installed on the outer surface of the outermost PFA corrugated ring. The PFA sealing gasket is filled in a stepped groove, which is embedded in one end of the first flange. The stepped groove can be pressed by a pressure ring, which is fixedly installed at one end of the second flange and located on the outer surface of the sealing ring cylinder.
[0015] In the aforementioned compression molding PFA lining equipment, the dovetail grooves are evenly distributed circumferentially along the inner wall of the metal tube, and the depth of the dovetail grooves is 0.8-1.5mm and the width is 1.2-2.0mm.
[0016] In the aforementioned compression molding PFA lining equipment, the thickness of the PFA liner is 2.5-4.0 mm, the corrugation height of the PFA corrugated ring is 1.5-3.0 mm, and the number of corrugations in the PFA corrugated ring is 3-5.
[0017] Compared with the prior art, the beneficial effects of this utility model are:
[0018] High-temperature compression molding creates a mechanical interlock between the PFA bushing and the dovetail groove on the inner wall of the metal pipe. This utilizes the corrosion resistance of PFA to isolate the medium from the metal, while the physical locking prevents the bushing from falling off, ensuring long-term corrosion protection for the metal pipe. Simultaneously, during flange connection, the sealing ring cylinder presses against the PFA bellows to form the first physical compression seal. The pressure ring simultaneously compresses the PFA sealing gasket within the stepped groove, forming the second line of defense. This dual sealing effect effectively prevents media leakage. Furthermore, the PFA material used throughout the process can withstand harsh conditions such as high temperature and high vacuum. The elastic structure also compensates for assembly errors and temperature deformation, ultimately achieving long-term stable operation of the equipment in highly corrosive environments, significantly improving its corrosion resistance, sealing performance, and service life. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of the two sets of metal pipes of this utility model assembled by the first flange and the second flange;
[0020] Figure 2 This is a schematic diagram of the sealing ring cylinder and the top pressure ring of this utility model;
[0021] Figure 3 This is a schematic diagram of the dovetail hook groove of this utility model;
[0022] Figure 4 This is a schematic diagram of the structure of the PFA bushing and PFA corrugated ring of this utility model;
[0023] Figure 5 This is a schematic diagram of the stepped groove and PFA sealing gasket of this utility model.
[0024] In the figure: 1. Metal pipe; 101. First flange; 102. Second flange; 103. Sealing ring cylinder; 104. Top pressure ring; 105. Dovetail groove; 106. Stepped groove; 2. Sealing mechanism; 201. PFA bushing; 202. PFA bellows ring; 203. PFA sealing gasket. Detailed Implementation
[0025] 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.
[0026] like Figures 1-3As shown, a compression molding PFA lining device includes: a metal pipe 1, with a first flange 101 and a second flange 102 respectively connected to both ends of the metal pipe 1. The first flange 101 can be bolted to the second flange 102 on another set of metal pipes 1. A sealing mechanism 2 is formed inside the metal pipe 1 by high-temperature compression molding.
[0027] Through the design of metal pipe 1, first flange 101, second flange 102, sealing ring cylinder 103, top pressure ring 104, dovetail groove 105 and sealing mechanism 2, the dovetail groove 105 is pre-set on the inner wall of metal pipe 1. Then, during high-temperature compression molding, PFA material is melted at a high temperature of 350-400℃ and filled into the dovetail groove 105 under pressure and completely adhered to the metal surface. After cooling, the sealing mechanism 2 is formed. The barbed structure of the dovetail groove 105 forms a mechanical engagement with the sealing mechanism 2, which enhances the tight connection and prevents the sealing mechanism 2 from falling off under high vacuum ≥-0.095MPa or pressure fluctuations. At the same time, the corrosion resistance of PFA is used to isolate the medium from contact with metal pipe 1.
[0028] When two sets of metal pipes 1 are spliced together through the first flange 101 and the second flange 102, the sealing ring cylinder 103 at one end of the second flange 102 will be inserted into the inner ring of the first flange 101, and it will press against the sealing mechanism 2 located there, causing it to collapse inward. The elastic deformation of the structure will tightly fill the gap between the sealing ring cylinder 103 and the inner wall of the flange, forming the first "physical compression seal". At the same time, the top pressure ring 104 on the second flange 102 is pressed into the stepped groove 106 of the first flange 101, forcing the corresponding part of the sealing mechanism 2 in the groove to deform, sealing the edge gap of the flange contact surface, forming the second seal.
[0029] Furthermore, the PFA material remains stable at 180℃, ensuring that the bonding strength between the sealing mechanism 2 and the metal is unaffected by temperature. The mechanical engagement of the dovetail groove 105 and the pre-tightening force of the sealing mechanism 2 work together to resist the internal and external pressure difference, preventing the sealing mechanism 2 from bulging. Moreover, the continuous corrosion-resistant barrier formed by the sealing mechanism 2 ensures that the medium does not come into contact with the metal parts throughout the process, thus avoiding corrosion leakage. This achieves the synergistic work of "metal structure support + PFA anti-corrosion seal", meeting the long-term stable operation requirements of harsh conditions such as strong corrosion, high temperature, and high vacuum.
[0030] like Figures 4-5As shown, the sealing mechanism 2 includes a PFA bushing 201. In its molten state, the PFA bushing 201 is filled into a dovetail groove 105 on the inner wall of the metal pipe 1 under pressure, and directly adheres to the metal surface of the metal pipe 1. One end of the PFA bushing 201 is fixedly connected to a PFA bellows ring 202, which is located within the inner ring diameter of the first flange 101. A sealing ring cylinder 103 extends from one end of the second flange 102. During the splicing process between the second flange 102 and the first flange 101, the second flange 102 can drive the sealing ring cylinder 103 to insert into the inner ring diameter of the first flange 101, exerting pressure on the PFA bellows ring 202, causing the PFA bellows ring 202 to collapse inwards.
[0031] When the PFA bellows 202 is compressed and collapses inward, its bellows structure undergoes elastic deformation. This elastic deformation tightly fills the gap between the sealing ring cylinder 103 and the second flange 102, forming a dual protection structure of "physical compression sealing + material corrosion-resistant barrier". The outer surface of the outermost PFA bellows 202 is extended with a PFA sealing gasket 203, which is filled in the stepped groove 106. The stepped groove 106 is embedded at one end of the first flange 101 and can be pressed by the pressure ring 104. The pressure ring 104 is fixedly installed at one end of the second flange 102 and is located on the outer surface of the sealing ring cylinder 103.
[0032] Through the design of PFA bushing 201, PFA corrugated ring 202 and PFA sealing gasket 203, PFA bushing 201, in a high-temperature molten state, fills the dovetail groove 105 of the inner wall of the metal pipe 1 by pressure and directly adheres to the metal surface. After cooling, it forms a mechanical interlocking structure, which not only utilizes the corrosion resistance of PFA to isolate the medium from the contact between the medium and the metal pipe 1, but also prevents the bushing from falling off through the physical locking of the dovetail groove 105, thus ensuring the long-term corrosion protection of the main body of the metal pipe 1.
[0033] When the two sets of metal pipes 1 are joined together via the first flange 101 and the second flange 102, the sealing ring 103 of the second flange 102 inserts into the inner ring of the first flange 101, simultaneously pressing against the PFA bellows 202 located there, causing it to collapse inward. This allows the bellows to tightly fill the gap between the sealing ring 103 and the inner wall of the flange through the elastic deformation of the bellows structure, forming a "physical compression seal." Simultaneously, the corrosion resistance of the PFA material itself constitutes a "material corrosion barrier," providing double protection for the sealing and corrosion prevention of the flange's inner ring. At the same time, the pressure ring 104 of the second flange 102... Together, they are pressed into the stepped groove 106 of the first flange 101, forcing the PFA sealing gasket 203 extending into the stepped groove 106 to be squeezed and deformed, thereby achieving a tight seal to block the gaps at the flange contact surface and edges, forming a second line of defense to further prevent media leakage. This allows the three to form a continuous PFA anti-corrosion sealing system, isolating the medium from the metal pipe 1 inner wall to the flange connection. Moreover, the PFA material remains stable under high temperature and high vacuum conditions, and the elastic structure can compensate for assembly errors and temperature deformation, ensuring that the equipment can operate reliably for a long time in harsh environments.
[0034] Specifically, in this embodiment, the dovetail grooves 105 are uniformly distributed circumferentially along the inner wall of the metal tube 1, and the depth of the dovetail grooves 105 is 0.8-1.5mm, and the width is 1.2-2.0mm. By limiting the uniform distribution of the dovetail grooves 105 along the inner wall of the metal tube 1, it can be ensured that the stress and bonding area between the PFA bushing 201 and the inner wall of the metal tube 1 are uniform during high-temperature compression molding, avoiding the risk of bushing detachment caused by weak local bonding; at the same time, the depth (0.8-1.5mm) and width (1.2-2.0mm) parameters of the dovetail grooves 105 are clearly defined, which can ensure that the PFA material is fully filled to form a stable mechanical interlock, and will not weaken the structural strength of the metal tube 1 itself due to the excessive size of the groove, thus taking into account the reliability of the lining bonding and the stability of the equipment support, especially suitable for the pressure difference resistance requirements under high vacuum (≥-0.095MPa) conditions.
[0035] Specifically, in this embodiment, the thickness of the PFA bushing 201 is 2.5-4.0 mm, the corrugation height of the PFA corrugated ring 202 is 1.5-3.0 mm, and the number of corrugations in the PFA corrugated ring (202) is 3-5. By limiting the thickness of the PFA bushing 201 (2.5-4.0 mm), the integrity of the corrosion barrier can be ensured while avoiding the reduction of the effective diameter of the metal pipe 1 due to excessive bushing thickness. By specifying the corrugation height (1.5-3.0 mm) and the number (3-5) of the PFA corrugated ring 202, the elastic deformation when it is pressed by the sealing ring cylinder 103 can be precisely controlled. This ensures that the corrugated structure can fully fill the gap to form an effective seal, while avoiding excessive deformation and fatigue damage due to excessive corrugation height / number, or insufficient sealing redundancy due to insufficient corrugation height / number. It is also suitable for thermal expansion and contraction compensation under high temperature conditions above 180°C, further improving the sealing durability of the flange connection.
[0036] Working principle: A dovetail groove 105 is pre-set on the inner wall of the metal pipe 1. During high-temperature compression molding, PFA material melts at a high temperature of 350-400℃ and is filled into the dovetail groove 105 under pressure, completely adhering to the metal surface. After cooling, it forms the core component of the sealing mechanism 2—the PFA bushing 201. The barbed structure of the dovetail groove 105 mechanically engages with the PFA bushing 201. Simultaneously, the corrosion-resistant properties of PFA isolate the medium from contact with the metal pipe 1. When two sets of metal pipes 1 are joined via the first flange 101 and the second flange 102, the sealing ring cylinder 103 extending from the second flange 102 inserts into the inner ring of the first flange 101, pressing against the PFA bellows 202 located there, causing it to... The corrugated structure collapses inward, and its elastic deformation tightly fills the gap between the sealing ring cylinder 103 and the inner wall of the flange, forming the first "physical compression seal". At the same time, the top pressure ring 104 on the second flange 102 is pressed into the stepped groove 106 of the first flange 101, forcing the PFA sealing gasket 203 in the groove to deform and seal the edge gaps of the flange contact surface, forming the second seal. Simultaneously, the top pressure ring 104 of the second flange 102 is also pressed into the stepped groove 106 of the first flange 101, forcing the PFA sealing gasket 203 extending into the stepped groove 106 to be squeezed and deformed, thereby achieving a tight seal to block the gaps of the flange contact surface and edges, forming the second sealing defense line, further preventing media leakage.
[0037] In summary, the three-layer sealing system forms a continuous PFA corrosion-resistant sealing system, ensuring that the medium does not come into contact with metal parts throughout the process, thus preventing corrosion and leakage. This achieves the synergistic effect of "metal structure support + PFA corrosion-resistant sealing," meeting the long-term stable operation requirements under harsh conditions such as strong corrosion, high temperature, and high vacuum.
[0038] All parts not described in this utility model are the same as or can be implemented using existing technology. Although embodiments of this utility model have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this utility model, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A compression molding equipment for PFA liners, characterized in that, The metal pipe (1) includes a first flange (101) and a second flange (102) connected to both ends of the metal pipe (1). The first flange (101) can be bolted to the second flange (102) on another set of the metal pipe (1). A sealing mechanism (2) is formed inside the metal pipe (1) by high temperature compression molding.
2. The compression molding equipment for PFA liners according to claim 1, characterized in that, The sealing mechanism (2) includes a PFA bushing (201), which, in a molten state, is filled into a dovetail groove (105) on the inner metal wall of the metal tube (1) by means of pressure, and is directly attached to the metal surface of the metal tube (1).
3. The compression molding equipment for PFA liners according to claim 2, characterized in that, One end of the PFA bushing (201) is fixedly connected to a PFA bellows ring (202), and the PFA bellows ring (202) is located within the inner ring diameter range of the first flange (101).
4. A compression molding PFA liner equipment according to claim 2 or 3, characterized in that, A sealing ring cylinder (103) is installed at one end of the second flange (102). During the splicing process of the second flange (102) and the first flange (101), the second flange (102) can drive the sealing ring cylinder (103) to be inserted into the inner ring diameter of the first flange (101) and exert a top pressure on the PFA bellows (202), causing the PFA bellows (202) to collapse inward.
5. A compression molding PFA liner equipment according to claim 4, characterized in that, When the PFA bellows (202) is compressed and collapses inward, its bellows structure undergoes elastic deformation. This elastic deformation can tightly fill the gap between the sealing ring cylinder (103) and the second flange (102), forming a dual protection structure of "physical compression sealing + material corrosion-resistant barrier".
6. The compression molding equipment for PFA liners according to claim 4, characterized in that, A PFA sealing gasket (203) is installed on the outer surface of the outermost PFA bellows ring (202). The PFA sealing gasket (203) is filled in a stepped groove (106). The stepped groove (106) is embedded in one end of the first flange (101). The stepped groove (106) can be pressed by a top pressure ring (104). The top pressure ring (104) is fixedly installed at one end of the second flange (102) and is located on the outer surface of the sealing ring cylinder (103).
7. A compression molding PFA liner equipment according to claim 6, characterized in that, The dovetail groove (105) is evenly distributed along the inner wall of the metal tube (1), and the depth of the dovetail groove (105) is 0.8-1.5mm and the width is 1.2-2.0mm.
8. A compression molding PFA liner equipment according to claim 1, characterized in that, The thickness of the PFA bushing (201) is 2.5-4.0 mm, the corrugation height of the PFA corrugated ring (202) is 1.5-3.0 mm, and the number of corrugations of the PFA corrugated ring (202) is 3-5.