Orifice set and chiller system having it

A throttling device, comprising:

• a tank for accommodating liquid refrigerant, with an orifice plate arranged at an outlet of the tank;
• a floating ball capable of floating on a liquid surface of the refrigerant;
• a pivot rod pivotally fixed on the tank through a pivot shaft;
• a connecting rod, with one end thereof fixedly connected with the floating ball, and the other end thereof fixedly connected with the pivot rod;
• a valve plate fixed on the pivot rod and located near an orifice of the orifice plate, wherein the valve plate is capable of adjusting a flow area of the orifice under action of the pivot rod;
• and
• a limit piece located above the valve plate and being movable, the limit piece configured to limit a position of the valve plate to establish a minimum flow area of the orifice;
• wherein a height of the chute is between the highest position and the lowest position of the orifice of the orifice plate.

A refrigeration system, comprising:

• a centrifugal compressor, a condenser, an economizer, an evaporator and a throttling device, the throttling device including:
• a tank for accommodating liquid refrigerant, with an orifice plate arranged at an outlet of the tank;
• a floating ball capable of floating on a liquid surface of the refrigerant;
• a pivot rod pivotally fixed on the tank through a pivot shaft;
• a connecting rod, with one end thereof fixedly connected with the floating ball, and the other end thereof fixedly connected with the pivot rod;
• a valve plate fixed on the pivot rod and located near an orifice of the orifice plate, wherein the valve plate is capable of adjusting a flow area of the orifice under action of the pivot rod;
• and
• a limit piece located above the valve plate and being movable to limit the valve plate,
• the throttling device being communicated with the condenser through an inlet pipe, and with the economizer through the orifice of the orifice plate,
• wherein the limit piece of the throttling device moves when preset surge conditions of the centrifugal compressor are met, so as to adjust a minimum flow area of the orifice.