Take the far-infrared radiation type tunnel sterilization dryer as an example. Other models can refer to corresponding changes.
1. Methods and functions
(1) Drying and sterilizing by far-infrared radiation heating. At the same time, it can ensure the heating, sterilization and cooling of bottles in a cleanliness level 100 environment;
(2) The sterilization temperature in the box can ensure that the bottles after sterilization are sterile and pyrogen-free. And at the outlet, the temperature of the bottle after cooling should be ≤ room temperature + 15°C.
2. Structure and manufacturing
2.1. Box structure and manufacturing
(1) The inner wall material of the box is made of high-quality austenitic stainless steel, with internal seams Continuous argon arc welding should be used, the weld must be flat and smooth, the bends should be round arc transitions, and there should be no dead corners or gaps in the hemming of the material. There are no blind spots in the structure, making it easy to clean and prevent the deposition of dust particles;
(2) The outer surface of the box can be made of high-quality austenitic stainless steel wire drawing plate or polished after production;
(3 ) The box has good thermal insulation performance. During normal use, the temperature rise of the outer shell surface is ≤ room temperature +12°C (excluding the inlet). The filling insulation material must not contain Cl-, and it is ensured that the oral liquid bottle and the air in the box will not be polluted;
(4) The structural design should consider the deformation of the box caused by temperature difference stress;
(5) The structure of the infrared heating tube should be able to ensure that the conductive connection device can work at high temperatures for a long time without oxidation.
2.2. Mesh belt and transmission
(1) The mesh belt material is selected and manufactured so that it does not turn black when heated, and the recommended material is 316L;
(2) There are two types of mesh belts (stainless steel wire winding type and chain plate type). It is recommended to use chain plate mesh belt. For the stainless steel wire string-wound type, there should be guide rollers on both sides of the mesh belt to correct the deviation; for the chain plate type, there should be guide grooves on both sides of the mesh belt to control the deviation;
(3) Structural requirements To ensure that there is no deviation or loose edges during operation, there are tensioning and supporting devices.
2.3. Clean air and filters
(1) A high-efficiency filter should be installed, the high-efficiency filter element must be resistant to high temperatures, and the sealing gasket can ensure sealing under temperature changes;< /p>
(2) There must be a certain static pressure distribution up and down the filter, and there must be a distribution plate for the air outlet.
2.4. Requirements for air ducts
(1) The layout of the air ducts is generally reasonably designed with top inlet and bottom outlet, and the air inlet should be connected to the corresponding HVAC system;
( 2) The air volume and speed of the front and rear circulation fans in the preheating and cooling sections can be independently adjusted or controlled by variable frequency. The wind speed in the preheating and cooling sections is generally 0.45m/s, and the wind speed in the high-temperature sterilization section is generally 0.6m/s;
(3) The circulation fan must be temperature-resistant, low-noise, and lubricated without leakage.
2.5. Testing and air dampers
(1) There should be sampling ports for collecting air samples and measuring temperature, air pressure and wind speed, which should be reasonably positioned and sealed. There are pressure difference measurement interfaces above and below the filter;
(2) Wind dampers need to be installed before and after the heating section on the inlet side and at the exit of the tunnel. The high and low positions can be manually controlled, and the adjustment and locking are easy.
2.6. Bottle in and out system
(1) It can adapt to the automatic bottle feeding of the conveyor belt. The inlet of the machine is equipped with an automatic bottle pushing mechanism so that the bottles entering the mesh belt are in a straight row. This can keep the wind pressure in the box relatively stable. At the same time, the bottle feeding should not be messy and disorderly;
(2) The bottle discharging system can automatically enter the bottle delivery carousel.
2.7. Others
(1) The oven manufacturing process should be in a relatively clean area. The inner wall and air duct of the oven after manufacture should be decontaminated, cleaned and disinfected with alcohol. Finally Use plastic paper to wrap the opening before leaving the factory;
(2) The inside of the whole machine is easy to clean and repair.
3. Electrical and control
3.1. Operation speed regulation
(1) The mesh belt will only start when the temperature in the box reaches the set value;
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(2) The speed of the conveyor belt is frequency-adjustable and displayed and recorded. The speed should be adjusted and controlled in conjunction with the front and rear processes.
3.2. Adjustment function
(1) The wind speed of the circulating fan can be adjusted in frequency;
(2) The temperature of each section can be independently controlled and set arbitrarily. The control accuracy is ±5°C, the heating section can be controlled within 300~380°C, and the running time of the 350°C high-temperature sterilization section is ≥5 minutes.
3.3. Control display and recording
(1) Adopt PLC control, touch screen display and operation, which can dynamically reflect the status of each process. There is a menu to select the running program or set the running parameters;
(2) Display and record of mesh belt speed and circulating fan speed;
(3) Temperature indication of each section and The curve is displayed in real time on the record or display screen, and the outlet temperature is indicated. The temperature indication and control temperature measuring elements should be independent. The indicated temperature of the heating section should be consistent with the actual temperature of the bottle. If it does not match, it must be corrected;
(4) The arrangement of the quartz electric heating tube should be reasonable to ensure that the box Uniformity of internal heat distribution;
(5) Normal display of wind pressure and wind speed in the box.
3.4. Chain requirements
(1) Normal electric heating can only be achieved when the front and rear circulation fans and exhaust air are turned on;
(2) The conveyor mesh belt only has Official production can only occur when the temperature everywhere in the box reaches the set value;
(3) There must be an operation interlock setting, which can alarm when the temperature does not meet the set value and automatically stop the mesh belt when the temperature is low. Chain operation, and keep each bottle in an environment of ≥350℃ for more than 5 minutes, or control according to process verification requirements;
(4) The program is set to shut down after work, the high temperature area slowly cools down, and the fan Still working, the machine officially shut down when the temperature dropped to 60°C.
3.5. Monitoring and alarm
(1) When the temperature in the box exceeds the set range, the heating will stop and the alarm will occur;
(2) When the circulation fan fails Or when there is a sudden power outage, an alarm should be issued to notify the manual windshield and stop heating. In order to prevent the filter from burning out, the interlocking device is considered in the control;
(3) The mesh belt overload fault can be mechanically separated and alarmed;
(4) The current and voltage of the heating element Real-time monitoring;
(5) The conveyor belt automatically stops and alarms under the following circumstances (conditional setting): bottle congestion at the exit of box a; bottle shortage at the import bottle b.
3.6. Online performance
(1) When the temperature inside the box and the circulating wind speed do not reach the set value, the bottle pushing mechanism can be controlled not to move or the front bottle washing machine stops;
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(2) When bottles are congested at the box outlet, the mesh belt can be controlled to stop automatically.
4. Installation environment requirements
(1) 100,000-level cleanliness space;
(2) The entrance and exit of the tunnel oven and the upper and lower processes The connecting section should be in a laminar flow environment with a cleanliness level of 100.
5. Main control indicators
(1) Drying bottle damage rate <0.1%;
(2) Mesh belt speed, in line with output requirements;
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(3) Dust particle monitoring in the box meets the 100-level cleanliness standard, and the high-efficiency filter needs to be tested for integrity. In addition, laminar flow test: preheating and cooling section: 0.45m/s±20%; heating section: 0.6m/s±20%; pressure difference test, the pressure difference between each section is >0Pa;
(4) Test that the equipment automatic control system is in the correct control state. The temperature difference between the acquisition instrument and the temperature display or temperature recorder is ≤1% of the full scale (i.e. ≤±5℃);
(5) No-load heat Distribution test, the temperature of each point is at the set value ≤±15℃ (for example, the sterilization heating section is 350±15℃);
(6) Load heat distribution and heat penetration test, verified by three loads , FH value ≥ 1365 minutes. The heat distribution and heat penetration test points can also be used to test whether the points are 350°C higher than the process sterilization temperature within 5 minutes after sterilization.