Absorption type refrigerating machine

In a double-effect absorption chiller wherein the vapor of a refrigerant produced by a high temperature generator is supplied to a low temperature generator 12 for condensation, and the refrigerant liquified by condensation is supplied to a condenser 11, a pipe 7 for supplying the refrigerant liquified in the low temperature generator 12 to the condenser 11 therethrough is provided with an orifice 71 and a control valve 81 as pressure adjusting means. A control circuit 9 is connected to the control valve 81 to hold the valve 81 fully open during the period form the start-up of the chiller until the load is stabilized and thereafter gradually decrease the opening degree of the valve 81. Alternatively, a control valve 118 is mounted on the pipe 7 for controlling the pressure of the refrigerant so that the concentration of the absorbent (intermediate solution) in the high temperature generator because equal to the average of the concentration of the absorbent (strong solution) in the low temperature generator 12 and the concentration of the absorbent (weak solution) in an absorber.