Atomizer
Compared to traditional medicines for the treatment of asthma and other respiratory diseases, the medical nebulizer atomizes the liquid into tiny particles, and the drug enters the respiratory tract and lungs through breathing inhalation to achieve painless, rapid and effective treatment. Medical devices.
Medical nebulizers are mainly used for the treatment of various upper and lower respiratory diseases such as colds, fever, cough, asthma, sore throat, pharyngitis, rhinitis, bronchitis, pneumoconiosis and other diseases occurring in the trachea, bronchus, alveoli, and thoracic cavity. Inhalation therapy is an important and effective treatment method for the treatment of respiratory diseases. Nebulizers are used to atomize liquids into tiny particles. The drugs enter the respiratory tract and lungs through respiratory inhalation to achieve painlessness. The purpose of rapid and effective treatment.
Second, the working principle of medical atomizer
A high frequency current medical ultrasonic nebulizer is an ultrasonic nebulizer by the ultrasonic generator through ultrasonic transducer is mounted in the spray tank so as to convert the high-frequency current of the same frequency sound waves generated by the transducer Ultrasonic waves are coupled through the atomizing cylinder and pass through the sound-transmitting membrane at the bottom of the atomizing cup so that the ultrasonic wave directly acts on the liquid in the atomizing cup. When the ultrasonic waves reach the conducting liquid from the surface through the bottom of the cup, the liquid - gas interface i.e. chemical cross-boundary surface and the air, after subjected to the ultrasonic perpendicular to the interface (i.e., energy effect), so that the liquid surface Tension wave, with the increase of the surface tension wave energy, when the surface tension wave energy reaches a certain value, the tension wave peak on the liquid surface also increases at the same time, causing the liquid mist particles at the peak to fly out (the diameter of the mist particles The size decreases as the frequency of the ultrasonic wave increases, ie the frequency of the ultrasonic wave is inversely proportional to the size of the mist particles). Since the mist particles generated by the ultrasonic wave have a uniform size and a very small momentum, it is easy to walk with the air flow, and the amount of mist particles generated by the liquid medicine increases with the increase of the ultrasonic energy (that is, the power of the ultrasonic wave is proportional to the amount of the mist particles). After the medical ultrasonic nebulizer drug was split into fine particles, and then gas flow generated by the blower means generates a spray mist, spray mist through the mist feed pipe delivered to the patient.
Third, the selection of atomizer should consider several aspects
There are many types of atomizers. Here, let's take a look at several aspects that should be considered when choosing an atomizer.
There are several aspects that should be considered when choosing an atomizer:
1. Full atomization can be achieved within the atomizer feed range. Rotary or nozzle atomizers (including pressure type and air flow type) can meet various production capacity requirements in the low, medium and high speed supply ranges. In the case of high throughput, rotary atomizers are more advantageous, although multiple atomizers can meet the requirements.
2. When the feed liquid is completely atomized, the power required by the atomizer (nebulizer efficiency) is the same. For most spray drying applications, the power required for various atomizers is approximately the same order of magnitude. When choosing an atomizer, the required power is rarely considered as an important issue. In fact, the energy input to the nebulizer far exceeds the energy theoretically required to split the liquid into droplets, so its efficiency is quite low. It is usually sufficient to meet the required spray characteristics at rated capacity, regardless of efficiency. E.g., three-fluid nozzle is particularly low efficiency, however, only when this atomizer to make certain high viscosity feed liquid atomization, efficiency become irrelevant.
3. Distribution of droplet diameter at the same feed rate. At low and medium feed rates, the droplet diameter distributions obtained with rotary and nozzle atomizers can have the same characteristics. At high feed rates, droplets produced by rotary atomizers generally have higher uniformity.
4 , the maximum and minimum droplet diameter (droplet uniformity) requirements. The maximum, minimum or average droplet size usually has a range that is required by the product characteristics. Blade-type atomizing wheels, two-fluid nozzles, or swirling airflow cup atomizers facilitate the creation of fine droplets. Blade-type atomizer wheels or pressure-type nozzles are generally used to produce moderate droplet diameters. Smooth disk atomizer or pressure nozzles are suitable for coarse droplet production.
5 , operational flexibility issues. From the standpoint of operation, the rotary atomizer has a greater elasticity than the nozzle atomizer. Rotary atomizers can be operated at a wide feed rate without significantly changing the particle size of the product. The operating conditions of the dryer do not need to be changed. Only the rotational speed of the atomizer wheel needs to be changed.
For a given nozzle, to increase the feed rate, it is necessary to increase the atomization pressure, and at the same time, the distribution of droplet diameter also changes. If there are strict requirements on the characteristics of droplets, multiple identical nozzles need to be used. If the atomization pressure is limited and the requirements on the droplet characteristics are not very high, only changing the nozzle aperture can meet the requirements.
6. The structure of the drying chamber should be adapted to the operation of the atomizer. When selecting various atomizers, the structure of the drying chamber plays an important role. From this point of view, the nozzle atomizer is very adaptable. The narrow nature of the nozzle spray allows it to be placed in a co-current, counter-current, and mixed-flow operating drying chamber. The hot air distributor can produce a rotating or parallel air flow. The rotary atomizer generally needs to be configured with a rotating hot air flow method.
7 , the nature of the material to adapt to the operation of the atomizer. For low-viscosity, non-corrosive, non-abrasive materials, rotary and nozzle atomizers are suitable for the same efficacy.
The atomizer wheel is also suitable for handling corrosive and abrasive slurries and various powdery materials; pumping problematic products under high pressure. The atomizer wheel is usually the first choice (although the air nozzle can also handle such materials).
Airflow nozzles are the best atomization equipment for processing long molecular chain structure feeds (usually high viscosity and non-Newtonian fluids). For many high-viscosity non-Newtonian feeds, they can also be preheated to minimize viscosity, and then atomized using a rotary or nozzle atomizer.
Each atomizer may have some situations where it cannot be applied. For example, a fibrous stock solution should not be atomized using a pressure nozzle. If the feed solution cannot withstand the impact, or although the amount of spray can be met, but the amount of atomizing air required is too great, the air-jet nozzle is not suitable. If the feed solution is a polymer containing long-chain molecules, only a filamentous product can be obtained with an impeller atomizer rather than a granular product.
8. The actual operation experience of the nebulizer of this product. For a new set of spray drying devices, the nebulizer is generally selected based on the prior experience with spray drying of the product. For a new product, laboratory tests and intermediate tests must be conducted, and then the most suitable atomizer should be selected based on the test results.
Fourth, the importance of atomizer particle size testing
Nebulized inhalation therapy is a very effective treatment for respiratory diseases. Atomization treatment generally uses a nebulizer to atomize the liquid into tiny particles. It is a way for the drug to inhale through the respiratory tract and the lungs, so as to achieve painless and rapid and effective purposes. The size of the atomized drug droplets directly affects the absorption of the drug. If the droplets are large and the atomization is fast, the patient will inhale too much water vapor to make the respiratory tract wet. The dry thick secretions in the respiratory tract that originally partially obstructed the trachea will swell after absorbing water and increase the resistance of the airway. This may result in hypoxia. It will cause the liquid to form water droplets hung on the wall of the lumen, causing a large demand for drugs, causing a waste phenomenon, and the effect of atomization therapy on the disease is not good. Therefore, the atomized particle size determines the therapeutic effect and quality of the atomizer. The winner311XP used in this test , the test report is as follows:
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