A unit for inflating an inflatable object includes a first sub-system for initially inflating the inflatable object and a second sub-system for automatically adding air to the inflatable object when the air pressure within the object falls below a predetermined threshold after inflation. The air pressure within the inflatable object is monitored and measured by an electric pressure sensor that communicates with a PC circuit board. The unit allows air into and out of the inflatable object using a solenoid configured to open and close a valve. The first and second sub-systems are both contained within the same housing affixed to the inflatable object and use the same solenoid and valve to add air into the inflatable object.

A lightweight transport vessel transports compressed natural gas underwater without needing to liquefy the gas for transport.

A tank system includes a vacuum tank having a vacuum tank skin, and a pressure tank mounted within the vacuum tank having one or more pressure tank skin segments having a total circumference that is less than that of a complete circle, resulting in one or more longitudinal gaps respectively between the one or more pressure tank skin segments. The tank system includes one or more gap control mechanisms configured to control a width of the one or more longitudinal gaps in a manner facilitating movement of the one or more pressure tank skin segments between at least the following positions: a retracted position in which there is a radial gap between each pressure tank skin segment and the vacuum tank skin, and a fully extended position in which at least a portion of each pressure tank skin segments is in contact with the vacuum tank skin.

The present invention provides a compressed fuel tank, comprising: an inner tank in which liquefied gas is stored; a support rod penetrating a central axis of the inner tank and having both sides of the inner tank fixed at both ends thereof; an insulating member provided to surround the inner tank so as to block heat transfer to the outside; an outer tank accommodating the inner tank, the support rod and the insulating member therein; and a rod support part fixed to both sides of the inside of the outer tank to support both ends of the support rod so as to transfer the load of the inner tank to both sides of the outer tank.