An elongate diffuser (10) comprises a diffuser body (30), and a membrane (20) attached so that introduction of gas at a working pressure into the diffuser displaces part of the membrane (20) from contact with the diffuser body (10) providing an elongate sealed compartment (50) between the membrane (20) and a surface (32) of the diffuser body (30). The gas can pass from the compartment (50) through the membrane (20) for aeration of fluid in which the diffuser (10) is immersed. The diffuser body surface (32) which bounds the compartment (50) is recessed away from the membrane (20) in use, to contribute to the lateral cross sectional area of the compartment (50) and facilitate distribution of gas along the diffuser by the compartment (50). An automatic purge valve for purging water from a gas feed pipe of a diffuser is also disclosed.

A bag assembly for use with a heat exchanger includes a flexible bag having of one or more sheets of polymeric material, the bag having a first end that bounds a first compartment and an opposing second end that bounds a second compartment, a support structure being disposed between the first compartment and the second compartment so that the first compartment is separated and isolated from the second compartment. A first inlet port, a first outlet port, and a first drain port are coupled with the flexible bag so as to communicate with the first compartment. A second inlet port, a second outlet port, and a second drain port are coupled with the flexible bag so as to communicate with the second compartment.

Systems and methods for aeration and mixing processes are disclosed.

A mixing aerator is disclosed that includes a housing defining a chamber having a bottom end and a top end, the housing having at least one inlet and at least one outlet; and a longitudinally extending diffuser disposed within the chamber and configured to deliver air bubbles into the chamber when the chamber is filled with liquid. The diffuser includes (a) a tubular elastomeric membrane having a plurality of perforations and, within the tubular elastomeric membrane, (b) an air pipe having a plurality of openings, the openings being larger and fewer than the perforations, and the tubular membrane having upper and lower ends that are sealed against an outer surface of the air pipe.

Systems and methods for aeration and mixing processes are disclosed.

A bag assembly for use with a heat exchanger includes a flexible bag having of one or more sheets of polymeric material, the bag having a first end that bounds a first compartment and an opposing second end that bounds a second compartment, a support structure being disposed between the first compartment and the second compartment so that the first compartment is separated and isolated from the second compartment. A first inlet port, a first outlet port, and a first drain port are coupled with the flexible bag so as to communicate with the first compartment. A second inlet port, a second outlet port, and a second drain port are coupled with the flexible bag so as to communicate with the second compartment.

An elongate diffuser is disclosed comprising a diffuser body and a membrane attached to the diffuser body. The membrane is connected to the diffuser body so that introduction of gas at a working pressure into the diffuser displaces part of the membrane from contact with the diffuser body to provide an elongate sealed compartment between the membrane and a surface of the diffuser body. The compartment has a first lateral side interface region where the membrane contacts the diffuser body, a laterally intermediate region where the membrane is spaced apart from the diffuser body and a second lateral side interface region where the membrane contacts the diffuser body. The diffuser body surface which bounds the compartment comprises a recessed portion which is recessed away from the membrane between the first second lateral side interface regions.

An all-ceramic diffuser supplies microbubbles of a narrow range of size to create a steady flow of bubbles of generally uniform size in an aqueous medium, such as process water in a wastewater treatment plant. The diffuser is formed of a porous body core, with pore sizes of e.g. 30 .Math.m or larger, an upper ceramic membrane that covers the upper surface of the body core, and has mean pore size of e.g., 3 to 15 .Math.m. A lower ceramic membrane covers the bottom surface of the body core, and has a finer pore size than the upper ceramic membrane, so that the capillary pore size of the smaller pores will act as a seal; consequently all of the air flow is through the upper ceramic membrane. A ceramic fitting connects the associated air supply with the porous body core which serves as plenum.

An aerator for aerating water comprises a distribution system for distributing air below the water surface and a compressor with an air inlet and at least one air outlet. The compressor is configured to be placed below the water surface. The infiltration of water at the air inlet is prevented by an intake pipe with one open end above the water surface and the other open end has a watertight connection to the compressor. The distribution system has a watertight connection to the air outlet and, due to its nature or by at least one valve, can hold back water. The housing is in thermal contact with the water to cool the compressor. The compressor is a centrifugal compressor that comprises an impeller that is driven by a shaft that it is mounted on air bearings, magnetic bearings or both.

A fine bubble generating device is provided, including: a main body, having an inlet, an outlet and a venturi tube mechanism located between the inlet and the outlet, the venturi tube mechanism having a neck portion communicating with outside; a bubble fining mechanism, having at least one passage which is smaller than the inlet in cross-sectional area, the at least one passage communicating with and between the venturi tube mechanism and the outlet. The bubble fining mechanism includes a first vortex member having at least one first slant hole and a second vortex member having at least one second slant hole. The at least one first slant hole and the at least one second slant hole are inclined toward opposite directions, and the first vortex member and the second vortex member is disposed between the venturi tube mechanism and the outlet.