A pressure vessel assembly incudes a pressure vessel and a gas density gauge. The pressure vessel includes a vessel wall defining an interior cavity. The gas density gauge includes a parallel plate capacitor having a pair of plates. Opposing surfaces of the plates are separated by a distance across an open gap. A capacitance of the capacitor is related to a density of a gas within the open gap.

The invention relates to a filling level measuring device for measuring the filling level in a container through the wall thereof by means of ultrasound, having an ultrasonic measuring head, a controller, and a fastening device by means of which the filling level measuring device can be fastened to the container such that the ultrasonic measuring head is pressed against the wall of the container. The invention further relates to a method of operating such a filling level measuring device, wherein a sampling rate is used which is situation-dependent. The invention finally relates to an assembly made up of such a filling level measuring device and at least one spacer which can be attached to the lower edge of a container to be provided with the filling level measuring device.

A storage vessel to contain reagent material. The storage vessel includes a vessel with a bottom, a top, an outlet at the top, sidewalls extending from the bottom to the top, a valve at the outlet, and an interior defined by the bottom, the top, and the sidewalls, the interior including a volume, and an extension tube having a first end engaged with the valve and a second end located toward a center of the interior volume from the first end such that, regardless of orientation of the vessel, the second end is above at least 25 percent of a volume of the interior volume.

A storage tank for liquid hydrogen having an outer tank , an inner tank which is arranged inside the outer tank , and a device for indicating a predefined fill level has been reached with a cell which can be arranged inside the inner tank and is filled with a gas which liquefies when the cell is dipped into the liquid hydrogen , further having a pressure indicator device which indicates a pressure drop in the cell in the case of liquefaction of the gas and therefore indicates the predefined filling level has been reached, and further having a heating element which continuously introduces heat into the gas .

Tank for storing liquefied gas comprising a sealed housing defining a storage space for the liquefied gas, the housing comprising a lower end and an upper end, the tank comprising a device for measuring the level of liquid in the housing, the device for measuring the level of liquid comprising, arranged in the housing, a float and a guide for moving the float, characterized in that the guide comprises an end connected to an upper portion of the housing and a lower end connected to a lower portion of the housing, the float being mounted moveably in translation on the guide such that the float is free to slide along the guide, the device for measuring the level of liquid further comprising at least one float position sensor.

A multi-vessel fluid storage and delivery system is disclosed which is particularly useful in systems having internal combustion engines which use gaseous fuels. The system can deliver gaseous fluids at higher flow rates than that which can be reliably achieved by vapor pressure building circuits alone, and that keeps pressure inside the storage vessel lower so that it reduces fueling time and allows for quick starts thereafter. The system is designed to store gaseous fluid in liquefied form in a plurality of storage vessels including a primary storage vessel fluidly connected to a pump apparatus and one or more server vessels which together with a control system efficiently stores a liquefied gaseous fluid and quickly delivers the fluid as a gas to an end user even when high flow rates are required. The system controls operation of the pump apparatus as a function of the measured fluid pressure, and controls the fluid pressure in a supply line according to predetermined pressure values based upon predetermined system operating conditions.

Some embodiments of the presently disclosed subject matter relate to a method and system for the real-time calculation of the amount of residual chemical energy in a non-refrigerated, pressurised tank containing liquefied natural gas, without a composition of the liquefied natural gas having to be determined.

A subsidence sensing device with a liquid replenishing mechanism has multiple liquid storage tanks connected with each other via communicating tubes, multiple level sensors, a liquid feeding tank disposed higher than liquid surfaces of liquids in the liquid storage tanks, and an air inlet tube and a liquid feeding tube communicate the liquid in the liquid storage tanks and feeding liquid in the liquid feeding tank. When the liquids in the liquid storage tanks evaporate gradually due to surrounding temperature or humidity, the feeding liquid in the liquid feeding tank flows into the liquid storage tank and replenish all of the liquid storage tanks via the communicating tubes. Thus, the liquid surfaces of the liquids in the liquid storage tanks can be kept at a predetermined proper liquid level, so as to allow the level sensor to provide accurate signals to monitoring staffs.

The invention relates to a filling level measuring device for measuring the filling level in a container through the wall thereof by means of ultrasound, having an ultrasonic measuring head, a controller, and a fastening device by means of which the filling level measuring device can be fastened to the container such that the ultrasonic measuring head is pressed against the wall of the container. The invention further relates to a method of operating such a filling level measuring device, wherein a sampling rate is used which is situation-dependent. The invention finally relates to an assembly made up of such a filling level measuring device and at least one spacer which can be attached to the lower edge of a container to be provided with the filling level measuring device.

An amount Y of liquid hydrogen that has passed through a first valve and has been volatilized during a predetermined time after first and second valves are opened is calculated by using a pressure P0 in an internal space of a liquid hydrogen tank measured before the two valves are opened, a pressure P1 in the internal space measured after the lapse of the predetermined time since the two valves are opened, and an amount X of the gaseous hydrogen that has passed through the second valve during the predetermined time. A fluid level H of the liquid hydrogen in the liquid hydrogen tank after the lapse of the predetermined time since the two valves are opened is calculated by using a expression showing a relationship between the H and an amount Y1 of the liquid hydrogen that passes through the first valve and drops therefrom, and the Y.