1. Work process

（1）The operation of an aerosol filling machine is usually divided into the following steps:

（2）Tank preparation: empty tank cleaning, drying and pre-inspection.

（3）Liquid filling: filling of formulated liquids (e.g. paints, pharmaceuticals, etc.).

（4）Propellant filling: adding liquefied gas or compressed gas propellant.

（5）Valve Installation and Sealing: Installation of valves and sealing of tanks.

（6）Pressure testing and quality control: testing for leaks and pressure stability.

2. Core scientific principles

(1) Quantitative control of fluid filling

Fluid metering technology:

Through high-precision pumps (such as gear pumps or peristaltic pumps) and flow sensors, based on Bernoulli's equation and Hagen-Poissuille's law (laminar fluid volume flow formula), control the liquid flow, to ensure that the filling volume error is less than ± 1%.

Vacuum-assisted filling:

Part of the equipment injects liquid after vacuuming in the tank to avoid gas bubble residue (utilizing the principle of gas partial pressure).

(2) Propellant filling and pressure balance

Liquefied gas filling (e.g. LPG):

The propellant is kept in liquid state at low temperature or high pressure and is filled by cryogenic condensation technique or high pressure injection system. The temperature and pressure are controlled to stabilize the liquefaction of the propellant according to the Clapeyron equation.

Compressed gas filling (e.g. CO₂, N₂):

Directly pressurized filling by compressor follows the ideal gas law and requires calculation of the pressure in the tank after filling (P₁V₁ = P₂V₂).

(3) Valve sealing and gas tightness guarantee

Rolled edge sealing technology:

The mechanical arm aligns the valve with the mouth of the tank and applies pressure to crimp the seal through a precision mold, using plastic deformation of the metal to form an airtight structure (based on the principle of material yield strength).

Leak detection:

After filling, the tank is immersed in water or bubbles are detected by helium mass spectrometer to verify the hermeticity (based on the law of gas diffusion).

3. Key technology and equipment modules

（1）Dual chamber filling system:

Some of the filling machines have a segregated design where the liquid and propellant are filled in steps to avoid premature reaction of the mixture (e.g. flammable substances).

（2）Pressure feedback control system:

Real-time monitoring of tank pressure through pressure sensors, combined with PID algorithm to dynamically adjust the filling rate (to prevent overpressure explosion).

（3）Low temperature filling technology:

For temperature-sensitive propellants (e.g. butane), a refrigeration system is used to maintain a low-temperature environment and inhibit vaporization (using the principle of latent heat of phase change).

4. Design for Safety and Efficiency

（1）Explosion-proof measures:

When charging flammable propellants, the equipment needs to comply with ATEX explosion-proof standards, use non-sparking materials and nitrogen inerting systems.

（2）Automation & AI Optimization:

Machine vision to detect tank defects and AI algorithms to optimize filling parameters (e.g. temperature, pressure) to reduce energy consumption.

（3）Environmentally friendly recycling system:

Collects volatile gases (VOCs) from the filling process and treats them by condensation or adsorption to reduce environmental pollution.

5. Application Scenarios and Technical Challenges

（1）Filling of high-viscosity liquids (e.g. hairspray): heating is required to reduce viscosity and screw pumps are used to precisely control the flow rate.

（2）Aseptic filling (medical sprays): operated in a clean room, the filling system needs to be resistant to high temperature and autoclave sterilization.

（3）Filling of miniature tanks (e.g. portable sprays): nanometer precision miniature valves and filling heads are required.

Summary

The scientific essence of aerosol filling machine is to realize efficient encapsulation of multi-phase substances (liquid + gas) within the safe pressure range through precise control of hydrodynamic parameters and mechanical properties of materials. Its design integrates the laws of physics (e.g., gas equation of state), mechanical engineering (e.g., sealing technology) and intelligent control (e.g., pressure feedback system), and is a typical representative of the modern chemical equipment field. With the advancement of technology, the filling machine is developing in the direction of being more efficient, more environmentally friendly and more intelligent.