By selectively communicating a liquid to be injected into the compression chambers to the economizer return line, the economizer return line and its ports are utilized for this liquid/vapor injection.

• 通过将一种将要注入压缩室的液体与节能器回流管路有选择地相连通，利用所述节能器回流管路及其注射口注入液体/蒸气。