A static defatting oven and oil vapor recovery system for polytetrafluoroethylene materials

Abstract

The utility model belongs to the polytetrafluoroethylene material processing equipment field, disclose a kind of for polytetrafluoroethylene material's static degreasing oven and oil gas recovery system, comprising: static degreasing oven is equipped with the oven body for placing polytetrafluoroethylene material, heating device, the sealing door and material bearing device for ensuring airtightness;Oil gas recovery system is communicated with oven by suction duct, sequentially including first stage condenser, second stage condenser, oil gas separator, liquid collection tank and the induced draft fan generating negative pressure;Control system is used to regulate and control heating temperature, degreasing time and oil gas recovery system operation.The utility model can realize the uniform heating and efficient degreasing of polytetrafluoroethylene material by optimizing the internal structure of oven and efficient multistage condensing recovery path, significantly improve oil gas recovery rate, reduce environmental pollution, and enhance equipment operation safety.

Description

Technical Field

[0001] This utility model relates to the technical field of polytetrafluoroethylene (PTFE) material processing equipment, and in particular to an oven and recovery system for static batch degreasing of PTFE materials and efficient recovery of organic solvent vapors generated during the degreasing process. Background Technology

[0002] Polytetrafluoroethylene (PTFE) is widely used in chemical, electronic, mechanical, and medical fields due to its excellent resistance to high and low temperatures, corrosion resistance, low coefficient of friction, and good electrical insulation. During the production of PTFE products, such as after compression molding, extrusion molding, or certain coating processes, the material or semi-finished product often contains processing aids, such as organic solvents like kerosene and naphtha. These organic solvents need to be removed in subsequent heat treatment (i.e., degreasing) processes to ensure the final performance of the PTFE products.

[0003] Existing PTFE degreasing processes, for continuous materials such as films, often employ continuous degreasing ovens, where rollers move the film within a heating zone to complete degreasing. For example, Chinese patent CN201610589100.1 discloses an intelligent degreasing and kerosene recovery device for polytetrafluoroethylene films, primarily targeting continuous degreasing and kerosene recovery for film products. However, continuous equipment is difficult to apply to the batch processing of discontinuous PTFE materials, such as PTFE parts, block materials, powders, or granules.

[0004] Currently, for static batch degreasing of such materials, general-purpose ovens or simply modified ovens are commonly used. These types of equipment often have the following problems:

[0005] Uneven heating: For stacked or irregularly shaped PTFE materials, ordinary ovens cannot guarantee that all parts are heated evenly, resulting in incomplete degreasing of some materials and overheating of others.

[0006] Low efficiency in oil and gas escape and recovery: A large amount of organic solvent vapor (oil and gas) is generated during the degreasing process. If the oven is not sealed properly or lacks an effective oil and gas collection and recovery system, the oil and gas can easily escape into the workshop environment, causing not only solvent waste and increased costs, but also environmental pollution and harm to the health of operators. Even when equipped with a recovery device, its efficiency in capturing and condensing oil and gas during the opening and closing of the door and the non-steady-state exhaust process of the static oven is often not high.

[0007] Safety Hazards: When organic solvent vapors mix with air to a certain concentration, they may ignite or explode upon contact with an ignition source. High concentrations of oil and gas can easily accumulate inside static drying ovens, posing a significant safety risk without reliable safety precautions.

[0008] Therefore, developing a static degreasing oven and oil-gas recovery system specifically designed for the static batch degreasing characteristics of PTFE materials, capable of achieving uniform heating, efficient oil and gas recovery, and ensuring safe operation, is of significant practical importance and application value. Utility Model Content

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a static degreasing oven and oil and gas recovery system for polytetrafluoroethylene (PTFE) materials. This system can achieve efficient and uniform degreasing of PTFE materials and efficiently recover the organic solvent vapors generated during the degreasing process, while ensuring the safety of the operation process.

[0010] To achieve the above objectives, this utility model provides the following technical solution:

[0011] A static degreasing oven and oil / gas recovery system for polytetrafluoroethylene (PTFE) materials include: a static degreasing oven comprising an oven body with an internal degreasing chamber for containing PTFE materials; a heating device disposed within the oven body or its wall for heating the PTFE materials in the degreasing chamber; a sealing door cooperating with the oven body for sealing the degreasing chamber; and a material supporting device disposed within the degreasing chamber for supporting the PTFE materials.

[0012] The system also includes an oil and gas recovery system, which is connected to the upper part of the degreasing chamber of the oven body via an extraction pipe. The oil and gas recovery system includes: at least one primary condenser for condensing the oil and gas containing organic solvents extracted from the degreasing chamber; a liquid collection tank connected to the condensate outlet of the at least one primary condenser for collecting the condensed organic solvents; and an induced draft fan located after the at least one primary condenser to provide extraction power for the oil and gas recovery system.

[0013] The system further includes a control system, which is electrically connected to the heating device and the induced draft fan, respectively, for controlling the heating temperature and holding time of the static degreasing oven, as well as the start-up and operation parameters of the oil and gas recovery system.

[0014] As a preferred embodiment, the at least one-stage condensation device includes a first-stage condenser and a second-stage condenser connected in sequence. The first-stage condenser is a water-cooled condenser, which uses ambient or low-temperature cooling water to initially cool and condense the high-temperature oil and gas, recovering most of the solvent. The second-stage condenser is a refrigerant-cooled deep condenser, which uses the low temperature (e.g., 0°C to -20°C or lower) generated by the refrigeration system to further cool the gas after the first-stage condensation, in order to recover more low-partial-pressure solvent vapors and improve the overall recovery rate.

[0015] As a preferred embodiment, the oil and gas recovery system is further equipped with an oil and gas separator (e.g., a wire mesh demister or a baffle plate separator) after the second-stage condenser and before the induced draft fan, to further remove tiny droplets that may be entrained in the airflow, prevent droplets from entering the induced draft fan, and improve the purity of the recovered solvent.

[0016] As a preferred embodiment, the inner wall of the oven body is provided with a flow guiding structure, such as a flow guide plate or a specially shaped liner, to optimize the circulation path of hot air in the degreasing chamber, ensure that hot air can flow evenly over the surface of the material, improve the uniformity of heating and degreasing, and guide oil and gas to accumulate in the direction of the exhaust pipe.

[0017] As a preferred embodiment, the static degreasing oven also includes a temperature probe (such as a thermocouple or PT100) and a pressure sensor mounted on the oven body. These sensors are connected to the control system to monitor temperature and pressure changes within the degreasing chamber in real time, providing a basis for the control system to precisely adjust process parameters and implement safety interlocks.

[0018] As a preferred embodiment, the static degreasing oven also includes a pressure relief device, such as an explosion-proof door or a safety valve, connected to the degreasing chamber. When the chamber pressure exceeds a preset safety value due to abnormal conditions (such as excessively rapid solvent evaporation), the pressure relief device can automatically open to quickly release the excessive pressure and prevent damage to the oven or more serious accidents.

[0019] As a preferred embodiment, the static degreasing oven is also equipped with an inert gas inlet, which communicates with the degreasing chamber and is connected to an inert gas source (such as nitrogen). Before the degreasing operation, inert gas can be introduced into the chamber to replace the air and reduce the oxygen content, thereby effectively preventing organic solvent vapors from reaching the explosion limit during the heating process and improving operational safety. Inert gas can also be introduced for protection during the later stages of degreasing or the cooling phase.

[0020] As a preferred embodiment, the material carrying device is designed as a multi-layered mesh tray or a special clamp customized according to the shape of the PTFE material. This design not only increases the contact area between the material and the hot air, facilitating heat transfer and oil / gas evaporation, but also adapts to the loading requirements of PTFE materials of different shapes and sizes.

[0021] As a preferred embodiment, the oil and gas recovery system is further equipped with an exhaust gas treatment device, such as an activated carbon adsorption device or a catalytic oxidation device, after the induced draft fan. This device is used to perform deep purification treatment on trace amounts of organic matter that may still remain in the exhaust gas after multi-stage condensation, ensuring that the emitted gas meets environmental protection standards and achieving clean production.

[0022] Compared with the prior art, this utility model has the following advantages:

[0023] 1) This utility model ensures that PTFE materials are heated evenly and degreased thoroughly during static batch processing through optimized internal heating design of the oven and appropriate material carrying method. It is especially suitable for materials with complex shapes or stacked, improving product quality and production efficiency, and improving degreasing efficiency and uniformity.

[0024] 2) This utility model adopts a multi-stage condensation combined with oil-gas separation technology, and with the micro-negative pressure operating environment formed by the induced draft fan, it can efficiently capture and recover high-concentration oil and gas generated during the degreasing process, significantly reducing the loss of organic solvents and environmental pollution; at the same time, the integration of safety measures such as inert gas protection, pressure monitoring and pressure relief greatly improves the inherent safety level of equipment operation, and realizes efficient oil and gas recovery and safe production. Attached Figure Description

[0025] 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.

[0026] Figure 1 This is a schematic diagram of the overall structure of a static degreasing oven and oil and gas recovery system for polytetrafluoroethylene materials according to this utility model.

[0027] Figure 2 This is a schematic diagram of the static degreasing oven in this utility model.

[0028] Figure 3 This is a schematic diagram of the oil and gas recovery system in this utility model.

[0029] In the diagram: 1-Static degreasing oven; 11-Oven body; 12-Heating device; 13-Sealed door; 14-Material carrying device; 15-Temperature probe; 16-Pressure sensor; 17-Pressure relief device; 18-Inert gas inlet; 2-Oil and gas recovery system; 21-Extraction pipe; 22-First-stage condenser; 221-Cooling water inlet; 222-Cooling water outlet; 223-Condensate outlet A; 23-Second-stage condenser; 231-Refrigerant inlet; 232-Refrigerant outlet; 233-Condensate outlet B; 24-Oil and gas separator; 241-Condensate outlet C; 25-Liquid collection tank; 26-Exhaust fan; 27-Tail gas treatment device; 3-Control system. Detailed Implementation

[0030] 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.

[0031] Please see Figure 1 , Figure 2 and Figure 3 This invention provides a static degreasing oven and oil vapor recovery system for polytetrafluoroethylene (PTFE) materials. The system mainly consists of a static degreasing oven 1, an oil vapor recovery system 2, and a control system 3.

[0032] A static degreasing oven 1 is used for heating and degreasing polytetrafluoroethylene (PTFE) materials loaded within it. It comprises a robust oven body 11, which forms a sealed degreasing chamber. Heating devices 12, such as electric heating tubes or resistance wires, are uniformly arranged on the walls or inside of the oven body 11 to provide the heat required for degreasing. The oven body 11 is equipped with one or more sealed doors 13, each fitted with a high-temperature resistant sealing strip to ensure good airtightness of the degreasing chamber after the doors are closed, preventing oil and gas leakage and the entry of outside air.

[0033] The degreasing chamber is equipped with a material carrying device 14, the specific structure of which is as follows: Figure 2 As shown, the oven can be designed with a multi-layer drawer-type mesh tray structure, or a special rack or tray can be designed according to the shape of the specific PTFE parts to facilitate uniform heating of the PTFE material and smooth evaporation of solvent vapors. The oven body 11 is also equipped with sensors for monitoring the internal conditions, including at least one temperature probe 15, which is typically installed at different locations within the cavity to monitor temperature uniformity, and a pressure sensor 16. Furthermore, for safety, the top or side wall of the oven is equipped with a pressure relief device 17, such as a spring-loaded safety valve or an explosion-proof diaphragm, and an inert gas inlet 18 for connecting to an inert gas source such as nitrogen.

[0034] The core function of the oil and gas recovery system 2 is to efficiently recover the organic solvent vapors volatilized from the static degreasing oven 1. This system is connected to the upper part of the degreasing chamber of the oven body 11, where the oil and gas concentration is high, via an extraction pipe 21. Under the negative pressure generated by the induced draft fan 26, the oil and gas first enter the first-stage condenser 22. The first-stage condenser 22 is typically a shell-and-tube or plate heat exchanger, using circulating cooling water as the cooling medium. The cooling water enters through the cooling water inlet 221 and exits through the cooling water outlet 222, initially cooling the high-temperature oil and gas and causing most of the high-boiling-point solvents to condense. The condensate is collected through the condensate outlet A 223.

[0035] The gas, after primary condensation but still containing some solvent, then enters the second-stage condenser 23. The second-stage condenser 23 uses a lower-temperature cooling medium, such as a cryogenic refrigerant circulated from an external refrigeration unit. This refrigerant enters through refrigerant inlet 231 and exits through refrigerant outlet 232, deeply cooling the gas, for example, to below 0°C, causing more low-boiling-point or low-concentration solvent vapors to condense. The condensate is collected through condensate outlet B 233.

[0036] The gas exiting the second-stage condenser 23 may still contain a small amount of mist-like liquid droplets, so it enters the oil-gas separator 24, which is typically a tank with a built-in wire mesh or labyrinth structure. Here, the gas undergoes collisions, coalescence, and other processes to effectively separate and capture the droplets, which are then collected through the condensate outlet C 241.

[0037] All condensate outlets 223, 233 and 241 are connected to the same or separate liquid collection tanks 25 for storing the recovered organic solvents, which can then be purified and reused.

[0038] After multi-stage condensation and separation, the gas is extracted by the induced draft fan 26. The induced draft fan 26 ensures that the entire recovery system maintains a slight negative pressure relative to the inside of the oven, which is conducive to the smooth extraction of oil and gas and prevents it from escaping into the workshop. If the exhaust gas discharged from the induced draft fan 26 still contains a small amount of organic matter that has not been completely recovered, it can be further passed into the exhaust gas treatment device 27, such as an activated carbon adsorption bed, for final purification before being discharged after meeting the standards.

[0039] Control system 3 is the brain of the entire equipment, typically using a PLC (Programmable Logic Controller) as its core, and equipped with a touch screen or other operation panel as the human-machine interface. Control system 3 is connected to the heating device 12, temperature probe 15, pressure sensor 16, induced draft fan 26, and related valves and refrigeration units in the oil and gas recovery system, as well as other actuators or sensors. Operators can set and monitor degreasing process parameters through control system 3, such as heating rate, degreasing temperature, holding time, cooling rate, inert gas charging timing and flow rate, and induced draft fan airflow. Control system 3 can also perform closed-loop control based on real-time data feedback from sensors and implement safety protection functions such as over-temperature alarm, over-pressure relief, and fault interlock shutdown.

[0040] The specific working process of this utility model device in actual use is as follows:

[0041] Step S1, Loading and Preparation: Open the sealed door 13 of the static degreasing oven 1, place the PTFE material to be treated on the material carrying device 14, and close and lock the sealed door 13.

[0042] Step S2, Pretreatment: Inert gases such as nitrogen are introduced into the degreasing chamber through inert gas inlet 18 to replace most of the air until the oxygen content reaches the safe set value.

[0043] Step S3, Heating and Degreasing: The control system 3 is activated, and the heating device 12 is started according to the preset program to heat the degreasing chamber. Simultaneously, the induced draft fan 26 and the cooling systems of each stage of the condenser in the oil and gas recovery system 2 are activated. Once the set degreasing temperature is reached, the temperature is maintained for a period of time to allow the organic solvents in the PTFE material to fully evaporate. The evaporated oil and gas are drawn into the oil and gas recovery system 2 by the induced draft fan 26.

[0044] Step S4, Oil and gas recovery: The oil and gas pass through the first-stage condenser 22, the second-stage condenser 23 and the oil and gas separator 24 in sequence. Most of the organic solvents are condensed and collected in the liquid collection tank 25.

[0045] Step S5, Cooling and Discharging: After degreasing, stop heating. Inert gas can continue to be introduced or the exhaust fan of the oil and gas recovery system can be used for auxiliary cooling. After the oven temperature drops to a safe level, stop the oil and gas recovery system, open the sealing door 13, and take out the degreased PTFE material.

[0046] Step S6, exhaust gas treatment: The exhaust gas discharged by the induced draft fan 26 is purified by the exhaust gas treatment device 27 before being discharged.

[0047] This invention, through its structural design and workflow, effectively enables static batch degreasing of PTFE materials in various forms, achieving efficient solvent recovery and safe, environmentally friendly production. Its structure is relatively compact, easy to operate, and highly automated, making it suitable for PTFE product manufacturing enterprises.

[0048] Although embodiments of the present invention 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 the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A static degreasing oven and oil / gas recovery system for polytetrafluoroethylene (PTFE) materials, characterized in that, include: A static degreasing oven (1); the static degreasing oven (1) includes: an oven body (11) having an internal degreasing chamber for containing polytetrafluoroethylene (PTFE) material; a heating device (12) disposed inside the oven body (11) or on its wall for heating the PTFE material in the degreasing chamber; a sealing door (13) cooperating with the oven body (11) for sealing the degreasing chamber; a material carrying device (14) disposed in the degreasing chamber for supporting the PTFE material; and an oil and gas recovery system (2), characterized in that the oil and gas recovery system (2) is connected to the oven body (11) via an extraction pipe (21). The upper part of the degreasing chamber is connected, and the oil and gas recovery system (2) includes: at least one condensing device for condensing the oil and gas containing organic solvents extracted from the degreasing chamber; a liquid collection tank (25) connected to the condensate outlet of the at least one condensing device for collecting the condensed organic solvents; an induced draft fan (26) located after the at least one condensing device for providing suction power to the oil and gas recovery system (2); and a control system (3) electrically connected to the heating device (12) and the induced draft fan (26) for controlling the heating temperature and heat preservation time of the static degreasing oven (1) and the start-up and operation parameters of the oil and gas recovery system (2).

2. The static degreasing oven and oil / gas recovery system for polytetrafluoroethylene materials according to claim 1, characterized in that, The at least one-stage condensing device includes a first-stage condenser (22) and a second-stage condenser (23) connected in sequence; the first-stage condenser (22) is a water-cooled condenser, and the second-stage condenser (23) is a refrigerant-cooled deep condenser.

3. As described in claim 2, characterized in that, The oil and gas recovery system (2) is further equipped with an oil and gas separator (24) after the second-stage condenser (23) and before the induced draft fan (26) for further separating liquid droplets entrained in the oil and gas.

4. The static degreasing oven and oil / gas recovery system for polytetrafluoroethylene materials according to claim 1, characterized in that, The inner wall of the oven body (11) is provided with a flow guiding structure to promote the uniform distribution of hot air and the directional flow of oil and gas in the degreasing chamber.

5. The static degreasing oven and oil / gas recovery system for polytetrafluoroethylene materials according to claim 1, characterized in that, The static degreasing oven (1) also includes a temperature probe (15) and a pressure sensor (16) installed on the oven body (11). The temperature probe (15) and the pressure sensor (16) are both connected to the control system (3) for real-time monitoring of the temperature and pressure inside the degreasing chamber.

6. The static degreasing oven and oil / gas recovery system for polytetrafluoroethylene materials according to claim 5, characterized in that, The static degreasing oven (1) also includes a pressure relief device (17) connected to the degreasing chamber, which automatically opens to relieve pressure when the chamber pressure exceeds a preset safety value.

7. The static degreasing oven and oil / gas recovery system for polytetrafluoroethylene materials according to claim 1, characterized in that, The static degreasing oven (1) is also provided with an inert gas inlet (18), which is connected to the degreasing chamber and is used to fill the chamber with inert gas before or during the degreasing process.

8. The static degreasing oven and oil / gas recovery system for polytetrafluoroethylene materials according to claim 1, characterized in that, The material carrying device (14) is a multi-layer mesh tray or a customized clamp to increase the contact area between the material and the hot air and facilitate the volatilization of oil and gas.

9. A static degreasing oven and oil / gas recovery system for polytetrafluoroethylene materials according to claim 3, characterized in that, The oil and gas recovery system (2) is further equipped with a tail gas treatment device (27) after the induced draft fan (26) for adsorbing or catalytically oxidizing residual organic gases that have not been completely condensed and recovered.

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