| 摘要 |
PURPOSE:To reduce useless compression work with an auxiliary compression element and a power loss due to friction by connecting a rotary shaft of a main compression element normally running to a driven shaft axially aliding on the auxiliary compression element for controlling On and OFF through a removable coupling. CONSTITUTION:When an auxiliary compression element is stopped, a small hole 23 provided in a lower bearing 13 is connected to intake ports 9, 21 in low pressure portions of a main compression element and the auxiliary compression element through a conduit 27, and a crank-shaft 14 contacts the lower bearing 13 by its own weight to stop at rest. When the auxiliary compression element is driven, the small hole 23 is connected to high pressure portions communicating from discharge ports 8, 18 of the main and auxiliary compression elements to an enclosed container and discharge port through a conduit 27 by a change- over valve so that the crank-shaft 14 of the auxiliary compression element is pushed up to the main compression element side to fit a projection 28 of the crank-shaft 14 in a recess 29 of the crank-shaft of the main compression element. |
