Refrigerant is a special kind of aerosol product, which is not only an effective liquid, but also a propellant, and also a liquefied gas. There are currently many substances that can be used as refrigerants, such as liquid ammonia, chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons. The Montreal Protocol stipulates a restrictive phase-out agreement on the application of Freon refrigerant. After 2005, vehicle refrigerants began to transition from difluorochloromethane (R22) to 1,1,2,2-tetrafluoroethane (R134a). At present, most domestic and foreign vehicle refrigerants specify R134a.
According to international classification standards, refrigerants are divided into two categories according to their flammability, one is non-flammable and the other is flammable. Flammable refrigerants must have special container requirements.
The internationally accepted aerosol cans product testing method is water bath detection, that is, the filled aerosol cans must be tested in water at a specific temperature of 55℃ to check whether the filled aerosol cans are at this temperature. Deformation, leakage, etc. may occur. The corresponding saturation pressure of the refrigerant at 55°C will be 1.5 times as an indicator for distinguishing high and low pressure refrigerants. Those higher than 1.8 MPa are high-pressure refrigerants, and those below 1.8 MPa are low-pressure refrigerants. For high-pressure refrigerants, there must be special corresponding container requirements.
For refrigerants, as long as one of the above classifications is met, the container must be supervised according to international standards and special permits must be applied for. If it is flammable or high-pressure, then the corresponding container requires a special permit. It requires high-pressure and flammable products for safety protection measures in production, manufacturing, transportation, and sales. All international refrigerant products require special permits because they are either high pressure or flammable. Taking R134a as an example, it meets the characteristics of high pressure. Its saturation pressure at 55°C is 1.5 MPa, 1.5 times the pressure is 2.25 MPa, which requires that the pressure of the container that can hold it must be higher than 2.25 MPa.
At present, my country has not compulsorily introduced the expression of the above two pressures for refrigerant metal container packaging, but has always followed the standards of aerosol cans GB 13042-2008 and GB/T25164-2010. The deformation pressure of the high-pressure tank specified in GB 13042-2008 is 1.8 MPa or more and the burst pressure is 2.0 MPa or more; the deformation pressure specified in GB/T25164-2010 is 1.2 MPa or more, and the burst pressure is 1.4 MPa or more. The pressures specified by the two standards are different.
In fact, the pressure specified by the two standards can not meet the actual demand. Take R134a, the most common small tank car air conditioner maintenance product on the market, and there have been countless accidents. On May 8, 2013, in an automobile repair shop in a certain city, when Tian Mou, a repairman, used a three-piece tank to charge the car with refrigerant, the aerosol tank exploded. The repairer’s right thumb was blown up and there were multiple cracks on the hand surface; 2013 At around 3 pm on July 8, 2005, a Santana sedan in a certain city exploded. The left rear door was deformed, the left side glass shattered, and a car next to it was also damaged. The right front door window glass exploded and the door was deformed, causing an accident The reason is that an aluminum refrigerant aerosol tank in the Santana car exploded.
According to statistics from several refrigerant packaging companies in the industry, similar accidents occur every year, of which 8 have occurred in a year. Each accident causes different casualties and large property losses. One of the most important reasons leading to these accidents is that the three-piece cans produced on the market basically cannot reach the required pressure.
The two-piece tank product can meet the two pressures specified above, and the deformation pressure test data has been higher than the required 2.25MPa. It can be seen that the application of two-piece tank to contain refrigerant is a suitable choice. Taking foreign countries as an example, the United States, Canada and other countries prohibit the use of three-piece cans to contain any refrigerant and all other flammable and explosive aerosol cans packaging products.
Starting from the requirements of the safety characteristics of refrigerants, choosing the right aerosol can packaging container has become an urgent task in the current standardized market. At present, the European and American markets are vigorously promoting the fourth-generation refrigerants, and 2,3,3,3-tetrafluoropropene (HFO-1234yf) with low global warming potential (GWP) has been used internationally to replace R134a refrigerant. Because HFO-1234yf is flammable, the safety requirements will be higher, so higher safety requirements will be put forward for small cans. Compared with three-piece cans, two-piece cans have incomparable advantages in safety. It can be seen that the use of two-piece cans in the refrigerant industry will become the mainstream in the future.
