A liquid cryogen stored in a liquid cryogen space of a closed insulated cryogenic storage vessel is subcooled by allowing it to enter into a conduit disposed in the liquid cryogen space where it is expanded by a pressure reducer in the conduit, thereby producing a cooled biphasic mixture of the cryogen in liquid and vaporized forms. The cooled biphasic mixture has a temperature lower than that of the liquid cryogen in the liquid cryogen space. Heat is transferred across the conduit from the liquid cryogen in the liquid cryogen space to the cooled biphasic mixture.

A pressure vessel for holding fluids includes a tank and a coating disposed on an outer surface of the tank. The tank defines a cavity for holding fluids, and an outer surface of the tank includes a first visual characteristic. The coating includes an indicator layer, an outer layer, and a first intermediate layer. The indicator layer is disposed on the outer surface, the indicator layer including a second visual characteristic that visually contrasts with the first visual characteristic. The outer layer is disposed over the indicator layer, the outer layer including a third visual characteristic that visually contrasts with the second visual characteristic. The first intermediate layer is positioned between the indicator layer and the outer layer, the first intermediate layer being visually transparent or translucent. The disclosure also describes a coating including an indicator layer, an outer layer, and a first intermediate layer.

A pressure vessel for holding fluids includes a tank and a coating disposed on an outer surface of the tank. The tank defines a cavity for holding fluids, and an outer surface of the tank includes a first visual characteristic. The coating includes an indicator layer, an outer layer, and a first intermediate layer. The indicator layer is disposed on the outer surface, the indicator layer including a second visual characteristic that visually contrasts with the first visual characteristic. The outer layer is disposed over the indicator layer, the outer layer including a third visual characteristic that visually contrasts with the second visual characteristic. The first intermediate layer is positioned between the indicator layer and the outer layer, the first intermediate layer being visually transparent or translucent. The disclosure also describes a coating including an indicator layer, an outer layer, and a first intermediate layer.

Disclosed herein is a floating ball filling-control device for a cryogenic tank with enhanced structural stability. The floating ball filling-control device comprises a liquid feeding pipe (2) with a liquid discharging end disposed in the liquid storage tank (1), the liquid feeding pipe (2) having liquid spraying holes (3) located on the pipe wall at the top of the pipe, and a slide valve (4) arranged on the top end of the liquid feeding pipe, wherein the slide valve is in a sliding fit with the liquid feeding pipe in a vertical direction via a floating ball lever driving mechanism, and forms an open/close mechanism for the liquid spraying holes via a control mechanism.

A liquid cryogen stored in a liquid cryogen space of a closed insulated cryogenic storage vessel is subcooled by allowing it to enter into a conduit disposed in the liquid cryogen space where it is expanded by a pressure reducer in the conduit, thereby producing a cooled biphasic mixture of the cryogen in liquid and vaporized forms. The cooled biphasic mixture has a temperature lower than that of the liquid cryogen in the liquid cryogen space. Heat is transferred across the conduit from the liquid cryogen in the liquid cryogen space to the cooled biphasic mixture.