Abstract: A submerged combustion apparatus for heating a liquid including a liquid vessel that contains the liquid, a combustion chamber including a combustion chamber body, an inlet and a plurality of discharge ports, the combustion chamber body being positioned in the vessel so that at least the discharge ports are submerged in liquid in use, a burner that allows an air/fuel mixture to be burned at least partially within the combustion chamber thereby causing bubbles of heated gaseous combustion products to be emitted from the discharge ports so as to heat the liquid and a guide surface spaced apart from and extending along at least part of a length of a combustion chamber body outer surface so as to guide bubbles emitted from the discharge ports so that the bubbles are at least partially constrained to flow between the combustion chamber body outer surface and the guide surface.

Abstract: A submerged combustion apparatus for heating a liquid including a liquid vessel that contains the liquid, a combustion chamber including a combustion chamber body, an inlet and a plurality of discharge ports, the combustion chamber body being positioned in the vessel so that at least the discharge ports are submerged in liquid in use, a burner that allows an air/fuel mixture to be burned at least partially within the combustion chamber thereby causing bubbles of heated gaseous combustion products to be emitted from the discharge ports so as to heat the liquid and a guide surface spaced apart from and extending along at least part of a length of a combustion chamber body outer surface so as to guide bubbles emitted from the discharge ports so that the bubbles are at least partially constrained to flow between the combustion chamber body outer surface and the guide surface.

Abstract: A linear variable differential transformer comprising a coil form; a first primary coil; an optional second primary coil; a first secondary coil; and a second secondary coil; wherein the windings of the secondary coils create complimentary and preferably uniform steps. Each step is preferably wound in at least two layers. In the embodiment comprising two primary coils, the inductive couplings between the primary and secondary coils cause null position to be physically centered within the transformer.