Adjustable venturi assemblies and methods of using adjustable venturi assemblies are disclosed. In one aspect, a venturi assembly for injecting a secondary fluid into a primary fluid flow path is provided. The venturi assembly comprises a nozzle, a constricted section in fluid communication with the nozzle, a secondary fluid conduit in fluid communication with the nozzle, and a flow adjusting device. The nozzle and constricted section together define the primary fluid flow path along a first axis. The secondary fluid conduit is for transporting secondary fluid from the secondary fluid reservoir to the constricted section along a second axis. The flow adjusting device is positioned opposite the secondary fluid conduit and is configured to alter a velocity of fluid flowing along the primary fluid flow path by extending into a portion of the constricted section along the second axis.

A pressurization and evacuation system is provided, including a top 3-way valve including a first port, a second port and a third port, a bottom 3-way valve including an first port, a second outlet port and a third port, and an educator including a pressure inlet, a suction inlet, and a discharge outlet. Wherein: a first conduit fluidically connects the top 3-way valve third port with the educator pressure inlet; a second conduit fluidically connects the top 3-way valve second port with the bottom 3-way valve first port; a third conduit fluidically connects the bottom 3-way valve third port with the educator suction inlet; and a fourth conduit fluidically connects the bottom 3-way valve second port with a customer apparatus.

A method for delivering air comprising the steps of: discharging a first air stream, wherein the mass flow rate of first air stream can be varied; and discharging a second air stream, wherein the second air stream is arranged to induce the first air stream to deliver a combined air stream with a mass flow rate that can be varied.