Abstract: Described herein is a method of removing refrigerant from a natural gas liquefaction system in which vaporized mixed refrigerant is withdrawn from the closed-loop refrigeration circuit and introduced into a distillation column so as to be separated into an overhead vapor enriched in methane and a bottoms liquid enriched in heavier components. Overhead vapor is withdrawn from the distillation column to form a methane enriched stream that is removed from the liquefaction system, and bottoms liquid is reintroduced from the distillation column into the closed-loop refrigeration circuit. Also described are methods of altering the rate of production in a natural gas liquefaction system in which refrigerant is removed as described above, and a natural gas liquefaction systems in which such methods can be carried out.

Abstract: Apparatus and methods for locking a discharge chute of a mixing vehicle are disclosed. The locking apparatus can be mounted to existing discharge chutes and frame arrangements and may utilize existing pneumatic systems of the mixing vehicle. The locking apparatus generally include a base having a first arm and a second arm pivotally secured to the base. An airbag may be positioned between the first arm and the second arm to bias a clamping region of the locking apparatus in a locked or a released state depending on the configuration of the locking apparatus.

Abstract: The identity of a calling subscriber unit (106) is provided to a called subscriber unit(s) (106') by requiring the calling subscriber to identify itself (112) to a central station (102 and 104a-c) and request across to the communicaiton resources. The central station forwards the identity of the calling subscriber to the called subscriber (114), which enables the called subscriber to decide whether to respond to (answer) the call. If the called subscriber responds, an RF communication link between the two subscriber units is established. Conversely, if the called subscriber does not respond (or responds negatively), the calling subscriber unit is provided with a "Busy" indication. Optionally, the central station may operate as a system-wide message recorder to store messages from calling subscribers for non-responding (Busy) subscribers. In this way, a calling subscriber may leave a message for later retrieval.