RG66001652_REV.02
20
LCW - LCR
2. Vacuum and charging machine
The charging piston compresses the refrigerant to a max P of 20 bar-r, thus favouring the re-condensation of any
flash vapour that may have formed during transit through the line between the tank -cylinder: consider fig. 1) in
which the saturated liquid (left-hand point on curve) undergoing slight pressure drops "enters" into the tank
generating flash vapour and ultimately a liquid-vapour mixture.
Opening the solenoid valve of the charging machine allows the passage of refrigerant liquid toward the charging
gun and flow is measured by the volumetric flow rate gauge; the quantity in weight is calculated by measuring the
T of the liquid, calculating its density (tables) and multiplying this value by the volumetric flow rate.
Given the constant pressure in the charging machine cylinder, the flow rate of the refrigerant mainly depends on
the cross section area of the charging nozzle and must be dimensioned so as to limit, in our case, the charging
speed to 2 kg per minute.
Tank
Cock
Charging
piston
Charging machine
Volumetric Flow
Rate Gauge
Solenoid
valve
Charging gun
Fig. 2
