Apparatus for the controlled supply of cryogenic fluid

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The depicted embodiment of apparatus according to the invention, which is intended to supply the liquid phase of a cryogenic fluid which is stored at a greater or lesser pressure in a tank 1, consists in essence of a phase-separator 10, a container 20 for collecting the liquid phase, an electrical control system 30 the function of which is to hold the liquid in container 20 at a constant level, withdrawal means 40, and distributor means 50.
The phase-separator 10 consists in essence of an enclosure 11, broadly in the shape of a cylinder whose central longitudinal axis is substantially vertical, the walls of which cylinder are heat-insulated and into which passes a duct 12.
The duct 12 is connected, via an electrical valve 13, to the storage holder 1.
The enclosure 11, which forms an expansion chamber for the fluid, has, in its upper part, a compartment 14 which is filled with a divided-up material 15 such as steel or copper wool.
The compartment is also provided with a vent 16 by which the gaseous phase can escape to the open air.
In its lower part the enclosure is provided with a discharge pipe 17 which opens from its bottom wall and through which the liquid phase 18 flows by gravity.
The container 20 is formed by a tank having heat-insulated walls 21 which has, at its upper part, an opening 22 which is closed by a cover 23.
Cover 23 has pipe 17 passing through it and is provided with a vent 24 to atmosphere.
Orifices 26 pass through the bottom wall of tank 21 and allow the liquid phase 27 to flow out by gravity.
At their ends, vents 16 and 24 are provided with protective means 19 and 25 respectively, which may be formed either by non-return valves which prevent the ingress of atmospheric air, or by a small cavity filled with a dessicant substance which is intended to trap the moisture in any air which may enter the separator or tank from the atmosphere.
The system 30 for controlling the electrical valve 13, which latter provides an all-or-nothing supply of cryogenic fluid to the phase-separator 10, consists of an electrical or electronic circuit 31 of a known type which feeds an electrical current to the said electrical valve as dictated by information supplied to it by means for detecting the level of liquid in tank 21, which detection means may for example be formed by two resistive or vapour-tension probes 32a and 32b which are attached to cover 23 and are located inside the tank at two different heights