Abstract: The sterilization oven is based on the original far-infrared drying and sterilization tunnel oven, introducing and digesting foreign advanced technology, and newly researching and developing the products for the water needle and powder needle line of the pharmaceutical factory. Indispensable drying and sterilization equipment.
1. Sterilization principle of tunnel sterilization dryer
In the antibiotic bottle small-volume injection drug production line, the antibiotic glass bottle is a package material that is in direct contact with the powder or the liquid medicine, and the corresponding aseptic production process requires the bottle to be dried and depyrogenated, and the tunnel sterilization dryer Dry heat sterilization is usually used. Dry heat often has two types of hot air parallel flow and far infrared heating. The overall tunnel structure is divided into three parts: preheating section, high temperature sterilization section and cooling section. After sterilization, the particles of antibiotic glass bottles reach the level 100 cleanliness requirement, the bacterial endotoxin drops 3 log units and the microorganisms are not allowed. Check out.
2, the type of tunnel sterilization dryer
Tunnel type sterilizer is also called tunnel oven. It mainly sterilizes, dries and depyrogenizes antibiotic bottles. There are two types of tunnel type heat sterilization. One is hot air circulation (that is, parallel flow of hot air), and the other is Far infrared radiation, the common point is dry heat sterilization.
2.1, hot air circulation type tunnel sterilization dryer
The hot air circulation type tunnel sterilizer was originally developed from the products of Bosch and BS. Its characteristics: (1) easy to control temperature and hot air pressure difference; (2) uniform temperature distribution; (3) the whole box length is shorter than the far infrared radiation type. However, the imperfections are as follows: (1) Hot air circulation type tunnel sterilization drying adopts high-efficiency filter with high resistance to higher than 350 °C, and its use cost is relatively high; (2) heating up due to hot air circulation type preheating section Faster, there is a certain requirement for the uniformity of the wall of the bottle.
2.2, far infrared radiation type tunnel sterilization dryer
In the sense, the far-infrared radiation type tunnel sterilizer is a domestic product that is born and raised, and is also derived from the evolution of Calumic and IMA. Its characteristics: (1) sterilized and dried by the radiant heat and hot air laminar flow brought by the hot air double role, strong thermal penetration; (2) the cost of spare parts is relatively low. However, the imperfections are as follows: (1) The airflow interference in the box and the opening and closing of the electric heating tube are greatly affected, and there are high requirements for the second-stage wind pressure control before and after the oven; (2) the box length ratio is determined due to the relaxation of the heating. The hot air circulation type is long; (3) only the whole row of bottles can be pushed in, so that the temperature of the bottles is basically the same, so that the heat penetration index can be basically ensured.
2.3. Comparison of two tunnel type sterilization dryers
Both types of tunnel-type sterilization drying ovens have their own characteristics, which can meet the requirements of pharmaceutical production. In 2000, the sterilization and drying of antibiotic bottles in China was generally selected from the traditional classic far-infrared heat radiation type. This is because of its low price and relatively low operating cost. It is very suitable for molding. bottle. Recently, however, since the antibiotic aseptic preparation uses a large number of controlled bottles, its thin wall and uniformity characteristics, combined with the control of the hot air circulation type and the uniformity of heat, make the hot air circulation type tunnel sterilization dryer widely used. It is also the first of its kind today.
3. Selection points of tunnel type sterilization dryer
This point is taken as an example of a far-infrared radiation type tunnel sterilizer. Other models can be referred to corresponding changes.
3.1, methods and functions
(1) Dry sterilization by far infrared radiation heating. At the same time, it can guarantee the heat sterilization and cooling of the bottle in the cleanliness environment of 100;
(2) The sterilization temperature inside the box ensures that the bottle is sterile and pyrogen free after sterilization. At the exit, the temperature of the bottle after cooling should be ≤ room temperature + 15 °C.
3.3. Structure and manufacturing
3.2.1. Box structure and manufacturing
(1) The inner wall material of the box is made of high-quality austenitic stainless steel, and the internal joints should be continuous argon-arc welding. The welds must be smooth and smooth, the corners should be arc-transition, and the material folds should not have dead angles and gaps. No blind spots on the structure, 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 post-polished;
(3) The insulation performance of the box is good. When the temperature is normal, the temperature of the outer surface of the casing is ≤ room temperature 12 °C (excluding the entrance), and the filling insulation material must not contain Cl-, and it is ensured that the oral liquid bottle and the air inside the box will not be contaminated;
(4) Structural design should consider the deformation of the box caused by the temperature difference stress;
(5) The structure of the infrared heating tube should ensure that the conductive coupling device works for a long time at high temperature without oxidation.
3.2.2, mesh belt and transmission
(1) The material selection and manufacturing of the mesh belt are not blackened by heat, and the material is recommended to adopt 316L;
(2) There are two kinds of nets (stainless steel wire-wound and chain plate type), and it is recommended to use chain plate mesh belt. For stainless steel wire-wound type, there should be a guide roller for correcting the deviation on both sides of the mesh belt; for the chain plate type, there should be a guide groove for controlling the deviation on both sides of the mesh belt;
(3) It is necessary to ensure that the operation does not run off and does not produce loose edges, and there are tensioning and tensioning devices.
3.2.3, clean air and filters
(1) High-efficiency filters should be provided, high-efficiency filter elements must be resistant to high temperatures, and gaskets can ensure sealing under temperature changes;
(2) There must be a certain static pressure distribution above and below the filter, and a distribution plate should be provided for the wind.
3.2.4, the requirements of the wind road
(1) The layout of the wind path is generally designed to be up and down, and the incoming air should be connected to the corresponding HVAC system;
(2) The air volume and wind speed of the front and rear circulation fans of the preheating and cooling sections can be independently adjusted or controlled by frequency conversion. The preheating and cooling section wind speed is generally 0.45m/s, and the high temperature sterilization section wind speed is generally 0.6m/s;
(3) The circulating fan needs temperature resistance, low noise and no leakage.
3.2.5, test and damper
(1) It should have a sampling sample port for collecting air samples and measuring temperature, measuring air pressure and measuring wind speed, and the position is reasonable and sealed. A measuring pressure difference interface is arranged above and below the filter;
(2) Windshield shall be provided before and after the heating section of the inlet side and at the exit of the tunnel. The high and low positions can be controlled by hand, and the adjustment and locking are convenient.
3.2.6, entering and leaving the bottle system
(1) It can adapt to the automatic feeding of the conveyor belt. The machine inlet is equipped with an automatic pushing mechanism, so that the bottles entering the mesh belt are arranged in a row, so that the wind pressure inside the box is relatively stable. At the same time, the bottle should not appear disorderly and disorderly;
(2) The bottle delivery system can automatically enter the bottle carousel.
3.2.7, other
(1) The oven manufacturing process should be in a relatively clean area. The inner wall and air duct of the box should be decontaminated, cleaned and disinfected with alcohol. Finally, the opening is sealed with plastic paper.
(2) The whole machine is easy to clean and easy to repair.
3.3, electrical and control
3.3.1, operation speed control
(1) The mesh belt is only activated when the temperature inside the box reaches the set value;
(2) The speed of the conveyor belt is adjustable, and it is displayed and recorded. The speed should be controlled with the interlocking of the front and rear processes.
3.3.2, adjustment function
(1) The circulating fan speed should be adjustable by frequency;
(2) The temperature of each section can be independently controlled and arbitrarily set. The control precision is ±5°C, the heating section can be controlled within 300~380°C, and the 350°C high temperature sterilization section running time is ≥5min.
3.3.3, control display and recording
(1) Adopt PLC control, touch screen display and operation, can dynamically reflect the status of each process. There is a menu to choose to run the program or to set the parameters to be run;
(2) Net belt speed and circulation fan speed display and recording;
(3) The temperature indication and recording of each section or the curve on the display screen in real time, the outlet temperature is indicated. The temperature indication and the control temperature measuring element should have their own independence. The heating section indicates that the temperature is consistent with the actual temperature of the bottle. If it does not match, it must be corrected.
(4) The arrangement of quartz electric heating tubes should be reasonable to ensure the uniformity of heat distribution inside the box;
(5) Normal display of wind pressure and wind speed in the box.
3.3.4, chain requirements
(1) Only after the front and rear circulation fans and exhaust air are opened, can the normal electric heating;
(2) The conveyor belt can only be formally produced when the temperature in the box reaches the set value;
(3) It is necessary to have the operation interlock setting, when the temperature does not meet the set value, the alarm and the low value can automatically stop the chain operation of the belt belt, and each bottle is more than 5 minutes in the environment of ≥350 °C, or verified by the process. Request for control;
(4) When the program is set to stop working, the high temperature zone slowly cools down, the fan still works, and the machine is officially stopped when the temperature drops to 60 °C.
3.3.5, monitoring alarm
(1) When the temperature inside the box exceeds the set range value, stop heating and alarm;
(2) When the circulating fan fails or suddenly loses power, the hand should be notified of the 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 from the combined alarm;
(4) Real-time monitoring of the current and voltage of the heating element;
(5) Under the following conditions, the conveyor belt will automatically stop and alarm (conditional setting): the bottle at the outlet of box a is congested; b the bottle is missing from the bottle.
3.3.6, online
(1) When the temperature inside the tank and the circulating wind speed do not reach the set value, the push bottle mechanism can be controlled not to move or the front bottle washer is stopped;
(2) When the bottle at the outlet of the box is congested, the mesh belt can be controlled to stop automatically.
3.4, installation environment requirements
(1) The 100,000-level cleanliness space;
(2) The connection section between the entrance and exit of the tunnel oven and the upper and lower steps shall be in a cleanliness level of 100 laminar flow environment.
3.5, the main control indicators
(1) The breakage rate of the baking bottle is <0.1%;
(2) Net belt speed, in line with production requirements;
(3) Monitoring of dust particles in the box, meeting the criteria of Class 100 cleanliness, and the high efficiency filter requires integrity testing. In addition, laminar flow test: preheating and cooling section: 0.45m / s ± 20%; heating section: 0.6m / s ± 20%; differential pressure test, each section of the pressure difference > 0Pa;
(4) The test of the correct control state of the equipment automatic control system, the full scale of the temperature difference between the collector and the temperature display or the temperature recorder ≤ 1% (ie ≤ ± 5 ° C);
(5) No-load heat distribution test, the temperature of each point is at a set value ≤ ± 15 ° C (such as 350 ± 15 ° C in the sterilization heating section);
(6) Load heat distribution and heat penetration test, after three load verification, FH value ≥ 1365 minutes. The heat distribution and heat penetration test points can also be used for a period of time after sterilization for 5 minutes, which is higher than the process sterilization temperature of 350 °C.
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