Refrigerant charging system and control system therefor

摘要

An apparatus and method for controlling the charging of refrigerant into a refrigerant system is disclosed. The apparatus determines the mass amount of refrigerant charged by determining the volume of refrigerant charged, the density of the refrigerant based on its pressure as it is charged, and determines the mass amount charged from the determined density and pressure. The apparatus has a pressure compensated flow valve and determines the volume of refrigerant charged based on the amount of time refrigerant has flowed through the constant flow valve. The type of refrigerant being charged can be selected from a plurality of refrigerant types and the apparatus has a memory in which data related to density and flow characteristics of each refrigerant type is stored. The apparatus uses the data for the selected refrigerant to determine the mass amount of refrigerant charged. The apparatus further determines that the refrigerant supply tank is empty when its pressure decay exceeds a predetermined amount. The apparatus has a manifold in which the constant flow valve is mounted and the apparatus can be made as a portable, hand carried unit. The apparatus can also be used as a mass flowmeter.