Aluminum aerosol cans are an important part of aerosol delivery products, and aerosol delivery products play a very important role in their functions. By definition, valves are mainly used for aerosol can products. They are closed mechanical devices fixed on the aerosol container. When they are closed, they will not leak content, and will release content in a prescribed form and speed.
The basic function of aluminum aerosol cans is to control the spray volume under airtight conditions. The plastic, rubber, aluminum or stainless steel used in the system must be inert to the contents. All parts need to be precisely machined and have appropriate strength. During storage, the swelling property must be kept within a certain limit to ensure the accuracy of the dosage. gender. The robustness, durability and structural stability of the valve system directly affect the quality of the preparation.
Aluminum can aerosol valve structure
The general structure is composed of plunger, fixed cover or mounting cup, internal gas, spring, valve body or valve chamber. From the structural point of view, the convex valve stem is higher than the small plane of the valve fixing cap, and the actuator is embedded on the valve stem; the actuator and the valve stem of the female mold valve are a combined structure, and the valve inserted into the valve is lower than the small plane of the valve fixing cap. At the extreme.
The working principle of aluminum aerosol cans
1. Fixed lid or sealed cup: the function is to fix the valve on the container, usually made of iron, divided into uncoated tinplate and coated. Or for aluminum products, apply epoxy film as needed.
2. Plunger: It is the axial part of the valve, usually made of nylon or stainless steel, including the inner hole and the expansion chamber. In the case of a metering valve, a thin container (drain container) is installed at the lower end to allow the product to enter the metering chamber. (Taishite Aerosol)
3. Valve body or valve chamber: play the role of quantitative spray. Its capacity determines the aerosol transmission to give an accurate dose at one time. The material is usually nylon. There are two small holes at the lower end into the container, which are blocked with rubber seals. In the case of canned propellant, the propellant can be injected into the container through the small hole due to the high pressure of the canning machine system, and the small hole at the rear of the can is also blocked by the gasket to prevent the content from leaking to the outside.
4. Infusion tube: It is connected to the lower part of the valve stem and plays the role of conveying the contents to the valve system. According to the method of intubation, it can be divided into an inner intubation tube and an outer intubation tube. Usually made of polyethylene or polypropylene. The working principle of the fog valve is the working principle. In the non-operating state, the valve becomes closed under the pressure of the spring. In the working state, after pressing the button, the valve stem moves downwards, the ejection hole of the valve stem leaves the sealing ring and becomes an open state. The valve stem and the valve body mixing chamber are connected. Under the pressure of the propellant, the content passes through the conduit, The valve body spray hole, mixing chamber, and finally through the valve body spray hole, valve stem, spray out from the button spray hole. After the valve stem is pushed back by the spring, the orifice of the valve stem is sealed and the valve is closed.
Inspection of aerosol valve of aluminum can
Valve inspection mainly involves appearance inspection, size standard inspection, aerosol valve leakage test, etc. There are corresponding inspection methods and inspection instruments in the national standard GB/T 17447-2012. More technical testing includes the detection of atomization effect, the detection of atomization angle, spray distance, spray volume, etc., as well as the detection of the pull-out force of the pipette. These tests can more accurately measure the performance of the valve to check the quality of the valve.
In the parts of the aluminum aerosol can, the filler seriously affects the sealing performance of the aerosol. There is a special test for gaskets, that is, the swelling test of the gasket. The gasket will expand and contract to a certain extent when it comes into contact with liquid, so the technical requirements for the gasket are very high. The immersion time for the swelling rate of aerosol-spreading products with different gasket materials in the raw material liquid to reach equilibrium is not necessarily. In most cases, the swelling rate of the sealing ring reaches an equilibrium point within 3 days to 2 weeks. However, some products, especially alcohol-based products, are a bit abnormal. In this case, the sealing ring will contract after it starts to expand for a period of time. The other is that the seal ring does not seem to have reached the equilibrium point. The mixture of liquid products will cause the seal ring to expand indefinitely, causing the molecular structure of the polymer to be completely broken. Therefore, the sealing ring must be used for a long time to carry out the immersion test of the sealing ring, and the leakage of the valve after 3 months of storage at high temperature and constant temperature must be used to judge the sealing performance of the sealing ring, and the applicability of the sealing ring must be verified through the dynamic operation test. Sex. Through the swelling test, it can be basically judged whether the material of the gasket used conforms to the product.
Selection of aerosol valves for aluminum aerosol can
The choice of sealing cup material: the thickness of the iron cup is usually 0.27mm, the thickness of the aluminum cup is usually 0.42mm, and the two materials can be used in the form of materials, and can also be used with layers of different materials. The commonly used ones are introduced below. Sealing cups of several materials:
The choice of gasket material: gaskets are usually divided into inner gaskets and outer gaskets. The materials are various, mainly: Buna, chloroprene, butyl, chlorobutyl, nitrile, chloroprene, polyurethane, etc. .
According to the different materials and propellants, choose the right material to adjust the ideal formula. You can also consult the valve supplier for the applicability of the material, which is a good way for beginners to speed up the development process. Different valve suppliers have different levels, so you can consult some top valve suppliers.
General recommendations: diner (water-based, alcohol-based), chloroprene (oil-based, solvent), butyl (DME, strong solvent), etc.
Selection of stem aperture: common sizes are 0.33, 0.41, 0.46, 0.51, 0.61mm, and the number of stem holes is one of the determinants of the ejection rate. There are also different series of the number of stem pores, there are 1, 2, 4, 6 and even 8 holes.
The choice of gas phase side hole: the gas phase side hole is located on the valve chamber body, and the valve is located inside after the valve is sealed. It is mainly used to increase the atomization effect, increase the ejection stability of the content of some powder products, and increase the ejection of high-viscosity products, etc. Features. There are single-hole and double-hole designs.
Selection of the length of the dip tube: the length of the dip tube can be set according to
Valve length = total height of tank-experience value
(The length of the valve is usually the length from the horizontal line of the valve cup to the bottom of the dip tube). Then pass the compatibility test to collect the shrinkage of the dip tube in the product, and finally set the valve height. The final valve length should be the bottom 1/3 of the semicircle of the bottom of the tank after the immersion is stable.
Summary:
The choice of aerosol valve for aluminum aerosol cans is not simply to get samples from the supplier, and then package and stability test can be done, but according to the physical and chemical characteristics of the product developed by the research and development engineers set what they want The material required, and then through the selection of different suppliers, you can first obtain the technical parameter table of the corresponding valve, according to the parameter table, you can simply read the useful information and the pre-judgment of whether the functionality can be satisfied, and then according to the product price and supply According to the level of the supplier, select reasonable samples for proofing, compatibility testing and stability testing.
Please note that it does not mean that the material of the sealing cup of the valve must be the same as the material of the aerosol can. R&D personnel can set it according to the characteristics of the product and verify it through the stability test.
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