螺杆式制冷机组运行初始阶段油温控制分析及改进

Analysis and improvement on oil temperature control for screw refrigeration compressor unit in initial operation stage

对螺杆式制冷机组运行初始阶段的油温控制特点进行分析,发现开机时过低的冷冻油温度会使其溶解制冷剂的能力增强,从而使冷冻油黏度和润滑能力降低,加速螺杆式压缩机运动部件的机械磨损。而目前使用热力膨胀阀的油冷却系统会使供油温度不断大幅波动,并超出使用范围。采用带有加热器的油气分离器,并通过PLC控制器利用PID调节方式对电子膨胀阀开度进行自动调节,从而控制冷冻油温度,可使上述问题得到解决。

The oil temperature control characteristics at the start of operation for screw compressor refrigeration unit are analyzed.It is found that the lower refrigeration oil temperature helps it to dissolve refrigerant in the initial operation stage,so that the viscosity and lubricating ability of refrigeration oil are reduced,which accelerates the mechanical wear and tear of moving parts of screw compressor.The oil cooling system with thermal expansion valve causes wild fluctuations of oil temperature constantly and makes oil temperature beyond the scope of use.Using an oil separator with heater and controlling the opening degree of electronic expansion valve using the PID adjustment method through PLC controller to control refrigeration oil temperature can solve these issues above mentioned.