BE412292A - - Google Patents

Description

       

   <Desc / Clms Page number 1>
 



  Cascade system and its method of operation.



   The present invention relates to a method and apparatus for transferring a volatile liquid, which has been produced at some expense and which releases a gas phase during transfer, from a region of relatively low pressure to a region. relatively high pressure with relatively small evaporative loss of the material.



   More specifically, the invention relates to a system of containers and to a mode of operation whereby loads of precious liquid material, that is to say of a material highly volatile at normal atmospheric pressure, for example a liquefied gas. such as certain liquefied hydrocarbons, liquid oxygen, liquid nitrogen, etc., are economically and rapidly transferred from a relatively low pressure supply vessel to a relatively high pressure receiving vessel in a manner. which causes significant recondensation of the gas phase

 <Desc / Clms Page number 2>

 in liquid in the transfer apparatus, so as to increase the net quantity of liquid transferred.



   The object of the invention is generally to provide an improved system and arrangement of receptacles as well as a method of operation for transferring successive loads of relatively cold liquid materials or of the nature indicated, from a supply vessel, at a relatively low pressure, into a final vessel at a relatively high pressure, in a manner which keeps the condensing capacity of the liquid high and uses it to reconvert the major part part of the gas phase into liquid, which reduces, to an industrially important extent, the losses produced when the gas phase is allowed to escape.



   More specifically, the object of the invention is to provide a system of transfer containers as well as an operating cycle for them with a view to effecting the transfer of a volatile liquid, in a succession of uniform charges, from a supply vessel to a receiving vessel through a number of stages of increasing pressure as the gas phase is passed in countercurrent;

   the transfer is effected in a manner which provides the condensing capacity in a series of increments so that the cooling of the liquid phase relative to the gas phase can be used with high practical efficiency, for the purpose of to effect a strong condensation of the residual gas phase into the liquid phase, so that the losses of the gas phase, when venting the initial transfer vessel, can be reduced to any desired low value .



   An object of the invention is to effect the desired transfer of charges from the material in a manner which effectively excludes any heat of external origin from the material.

 <Desc / Clms Page number 3>

 during transfer before a determined point, such as the discharge end, in the transfer path in order to reduce as much as practicable the release of the gas phase in the transfer path before that determined point . This exclusion is preferably accomplished in such a manner that the heat which is imparted from outside the system is substantially excluded while the heat imparted to the liquid from parts of the system is raised to a temperature. very low value.



   Yet another object is to provide a system of transfer containers and an operating cycle, intended to effect the rapid transfer of liquefied gases for industrial consumption, in particular liquid oxygen, from a gas container. transport which is at a relatively low pressure, to a receiving device such as an evaporator or a storage vessel at a relatively high pressure, so that industrial consumers can be served quickly in a manner which minimizes gligeable what is called blowing to the atmosphere, and that allows the economical flow of liquid or gas in strongly separated points, in variable quantities, with ease and speed.



   Other objects of the invention will appear themselves or will be pointed out below.



   The invention therefore includes the various operations and the relation of one or more of these operations to each other, and the apparatus comprising the construction features, the combinations of elements and the arrangement. parts which are suitable for carrying out these operations, all as indicated by way of example in the detailed description which follows and whose scope of application is specified in the claims.



   For the full understanding of the nature and purposes

 <Desc / Clms Page number 4>

 of the invention, reference is made to the detailed description given below with the aid of the accompanying drawings in which:
Fig. 1 is a view, partly in section and partly in elevation, showing an embodiment of the invention on a vehicle and intended to industrially transport a liquefied gas, such as liquid oxygen, and to transfer it. the latter by means of what are called here cascaded containers to a transportable evaporator to serve industrial consumers of oxygen gas.



   Fig. 2 is a view, partly in section and partly in elevation, showing a simple system comprising cascaded vessels for transferring liquefied gas in accordance with the present invention.



   Fig. 3 is a similar view showing a more complicated system of containers connected so as to incorporate the cascade principle, according to the present invention.



   Fig. 4 is a similar view showing a still more complicated system of containers, part of which is connected in series and part in parallel for transferring liquefied gas in accordance with the present invention.



   Fig. 5 is a view partly in elevation and partly in section of yet another system, comprising vessels connected partly in series and partly in parallel, incorporating the principle of the cascade and intended to perform rapidly transfer liquefied gas in accordance with the present invention.



   Figs. 6 and 7 are explanatory diagrams.



   It has heretofore been proposed to transfer liquid material of low volatility, which is substantially stable at temperature and atmospheric pressure, from regions of low pressure to regions of high pressure.

 <Desc / Clms Page number 5>

 by means of receptacles connected in a manner capable of imposing successively increased pressures, in a manner somewhat analogous to the use of locks in the canals for navigation, connecting different water levels . These prior arrangements have never encountered or solved the problems encountered by the present invention.



   The present invention provides a system of constant volume transfer vessels and an operating process cycle for effecting communication therebetween, whereby substantially uniform loads of liquid are subjected to a succession of increased pressures up to and including. that they have passed to the desired high pressure, the gaseous phase present in the receptacles being sent in the opposite direction in a heat exchange relationship with the liquid and subjected to an inverse succession of pressures, in such a way that a significant portion of the gas phase is re-condensed to liquid at each of the sub-successively lower pressures.

   The number of stages employed is preferably such that the total condensing capacity of the liquid is used to as great an extent as possible; the transfer liquid condensation products being obtained to such an extent that the material in the gas phase remains in an initial vessel which is lowered to the. atmospheric pressure, is reduced to a value which is practically negligible. A system of communicating vessels which receives charges of liquid and effects the countercurrent passage of this material in the gas and liquid phases in stages, in such a way that the liquid phase passes from a region of low pressure in an area of high pressure, is for brevity called a cascade system.



   The heat exolusion of the cascade system of the present invention is preferably accomplished in the former case by the use of means associated with the transfer vessels.

 <Desc / Clms Page number 6>

 fert to insulate the containers from heat from outside the system. Any suitable heat insulating agent can be employed for this purpose, for example a casing of magnesium carbonate.



   There is of course a certain amount of heat which may be imparted additionally to the liquid from parts of the system, such as that remaining in the walls of transfer vessels due to their heat capacity and retained after each passage of gas and even- pressure sation. This heat is communicable to the next charge of liquid entering the container since the walls are heated by the gas phase and are at a temperature slightly higher than the temperature of the next charge. To substantially exclude the entry of this heat into the liquid, when so admitted, the heat capacity of the medium containing the liquid is made relatively small.

   This is preferably accomplished by providing the transfer vessels or a desired portion thereof with coatings of a nature which substantially retards the conduction of heat between the walls of the vessel and its support; a preferred form includes thin metal receptacles or baskets which have relatively small mass and low specific heat and contact and retain liquid. Such a basket is preferably shaped to fit within the interior of the container and is spaced apart from the interior walls by means of spacers having relatively low thermal conducibility.

   A suitable construction of containers, baskets and spacers is given in United States Patent No. 1,948,477 issued February 20, 1934 to Zenner. 'The pipes used to connect the receptacles may be provided with a coating.

 <Desc / Clms Page number 7>

 completely analogous, if desired.



   The exclusion of heat, as proposed, is important in effecting the transfer of volatile liquids of the nature indicated, because of the relatively large temperature differences encountered and the generally small latent heats of the materials which are vaporized. Otherwise, heat entering from the outside and communicable heat from parts of the system can cause excessive production of a gas phase during the transfer being made. Liquid oxygen has a very small latent heat, which becomes smaller as the critical pressure approaches. Therefore, it is seen that it is desirable to make the exclusion of heat practiced here most stringent for vessels which are associated with the highest pressures.

   When the pressures are low, that is to say in the vicinity of a few atmospheres, or when certain liquefied hydrocarbons are transferred, the use of baskets can be dispensed with.



     The exclusion of the heat used here preserves the condensing capacity of the liquid, in addition to the reduction in mass of the gas phase produced. The refrigeration of the liquid is thus kept in a very efficient manner so that a certain amount of condensate is obtained which is a-
Added to the transferred liquid phase.



   It is also seen that a liquefied gas such as liquid oxygen contains a storage of so-called available energy due to its low temperature and its high density.



   This available energy can be used in a suitable apparatus to cause the spontaneous compression of the fluid from a low pressure liquid to a high pressure gas and to deliver the latter to a suitable point outside the system.



   This is done, as can be seen, without any additional energy input other than the heat of the space in-

 <Desc / Clms Page number 8>

 veering, such as that of the surrounding atmosphere and without appreciable loss of material.



   It is proposed, however, to introduce heat in an adjustable manner, when desired, to accomplish the final gas conversion. This is done when the material to be transferred reaches a certain point, for example an evaporator. This can be done at other points, however, particularly in a vessel in which the material passes through critical temperature and pressure. At these pressures, the transfer under the operating forces of a system which depends on a difference in densities becomes relatively inefficient. For this purpose, it is envisaged to provide this transfer container with a means of introducing adjustable heat.



   The essential nature of the present cascade system can be seen from the simple system shown in fig. 2.



  On this two interconnected transfer vessels a and b which are shown coated and provided with thermally insulating envelopes are arranged to effect a transfer of loads of nature. indicated in two stages from a supply vessel c, which serves as a source, at a relatively low pressure, to a receiving vessel shown here as an evaporator d, to which the controlled supply thermal energy is applied to transform matter into gas at a desired high pressure.

   While the transfer vessels a and b are arranged to pass the loads of the material transferred from each vessel successively, thus referred to as a series arrangement, it is also contemplated to employ an arrangement in which the material passes into a transfer container but only once, the material from c being sent to the containers alternately. A similar arrangement is called a

 <Desc / Clms Page number 9>

 parallel arrangement. It is also to be envisaged to employ containers connected partly in series and partly in parallel, in systems employing three or more containers.



   In the arrangement shown in FIG. 2, a determined quantity of liquid comprising a charge is passed through an inlet duct 10 into the initial vessel a under the influence of a force such as that obtained by a pressure acting in the system. , the charge being admitted through the opening of the control valve 11. To admit the charge, the gas in the container a is displaced.



  This is done by an outlet or blowing duct 12 which is controlled by a valve 13. When this duct is opened, it allows the gas to escape directly into the atmosphere while the liquid. enters through line 10. To admit a substantially uniform amount of liquid to each charge, a measuring device is associated with the container a such that the flow is stopped when a desired amount of liquid has entered.



    Any suitable measuring device may be employed for this purpose, for example a liquid level actuated shutter for line 12, which automatically closes the latter when the desired amount has entered.



  In the arrangement shown, this is achieved by extending the conduit 12, as has been shown at 12 ', in the container.! so that the mouthpiece is at the liquid level reached when the desired amount has entered. The flow of liquid from the container is stopped as soon as the determined level, represented by the liquid rising in the conduit 12 ', is reached in the reoipient a. The material thus admitted into the container a expands when it is heated by the heat exchanged with the gas phase.

   Accordingly, the filling

 <Desc / Clms Page number 10>

 The proper size of the container a is determined by the nature of the liquid transferred since it is desired to have a gas space in the container a to allow this expansion to take place without overflowing the coating or the coating. deny. The blowing of the residual gas from the container a, here envisaged, need only reduce the pressure of the container a sufficiently below that of the container to achieve the desired flow.



   When it is desired to transfer material from container a to container b, valve 14 in connection 15 is opened to first allow a flow of gas which may have remained in container b as a residue from a previous operation, this gas flowing in the liquid charge of the container a. Direct contact heat exchange occurs between gas and liquid so that part of the gas is condensed as the temperature of the liquid is raised and a pressure equilibrium condition is finally reached. and a temperature which is above the initial conditions of the liquid charge and which is below the pressure initially existing in the vessel b. The liquid is then drained from container a to container b using the force of gravity.

   This flow is facilitated by the existence of a gas communication conduit 16, controlled by a valve 17 which, when opened, allows the movement of gas from vessel b to vessel a through the valve. quid which flows from the receptacle a to the receptacle b.



  The volume of container b may not be the same as that of container a; for example it can be larger in order to provide a gas and liquid space therein which allows in a desired ratio the expansion of gas and liquid when they are brought to an average temperature above that prevailing in the container a.

 <Desc / Clms Page number 11>

 



  It can be seen that the internal energy of the pressurized gas in vessel b, when oelui-oi passes into the liquid of vessel a, is absorbed by the liquid of a because of the condensing capacity of oelui-oi, with a resulting condensation of the gas phase in the liquid phase. There is consequently a redistribution of the internal energy of the system comprising the receptacles a and b, without noticeable change in the total internal energy of the system, since the heat of external origin is strictly excluded and that 'no outside work is done. This series of operating processes can therefore ideally be called adiabatic pressure equalization, although in practice there may be some heat leakage in the system.



   The liquid feed, now in vessel b, is discharged to evaporating vessel d which is shown as a coil disposed in a casing 24 and exposed to heating fluid circulating in the casing. . The discharge is produced by the use of an external force, such as gravity, when the valve 18 controlling the outlet pipe 19 to the evaporator is opened and the gas pressures are equalized by the opening of the valve 20 in the duct 21. Forces of displacement of the liquid of external origin, other than the force of gravity can also be used as will result from the desorption of Figs. 3 and 4.



   The liquid flowing into the evaporator d is vaporized by the heat supplied to it, and the pressure in the system comprising the vessels b and d rises to a relatively high desired value. A desired quantity of the gas thus produced is sent to storage containers and / or consumption devices which are

 <Desc / Clms Page number 12>

 coupled to the system in e, by flow in the conduit 22 when the valve 23 is open. The heat which produces the pressure to effect evacuation is controllably supplied to evaporator d and most of it is contained in the material discharged through conduit 22.



  However, a considerable amount of heat in the form of internal energy remains in the gas left in the vessel after evacuation. It is this energy and the material containing it that can be returned to the transferred liquid to any extent desired by the application of the cascade principle. In the example of FIG.



  2, much of this energy is retained in the system by condensing gas from vessel b into a fresh charge of liquid in vessel a.



   The actual discharge from the outgoing system at a is less in mass than the mass of the charge supplied to the feed container, the mass of the blow molding, and therefore the net discharge represents the material passing through the system. of cascade in the direction of the initial container to the final container while the net blow or net loss represents the net material passing in the reverse direction.



   The principle of the operation can be more easily understood by referring to figs. 6 and 7, among which FIG. 6 schematically shows the internal heat and energy transfer which takes place in the system between the vessels a and b, while FIG. 7 shows in an analogous manner the mass flow of material through the system and the redistribution of gas displaced through the system during transfer between vessels, as seen from the detailed description of these figures given herein. -after.



   In the representation given here, the volumes of the receptacles a and b (hereinafter called va and vb) are obviously constant. For the purposes of analysis, it was assumed that these

 <Desc / Clms Page number 13>

 Condensation occurs so quickly and the vessels are so well insulated that no heat enters the material or leaves the material of vessels a and b during the oondensation operation. Then for the system including the vessels a and b the first law of thermodynamics gives: dQ = .dU + dW .......... (1 formula in which dQ designates the heat added to the system from the outside .dU denotes the internal energy changes of the system dW denotes the work done by the system to the exterior.



   We obviously have dQ = 0 and as the volume of the system is constant, dW = 0, therefore dU = 0 which means that the change in internal energy of the system before and after the condensation is zero or that the energy internal remains constant. The internal energy of a gas is a function of temperature only for an ideal gas, but is also a function of pressure for imperfect liquids and gases.



   If mf denotes the mass of liquid and gas in vessel a mg denotes the mass of gas in vessel b prior to the equalization flow. uf denotes the internal energy per unit mass in the container a ug denotes the internal energy per unit mass in the receptacle b, we have: mfuf + mgug = Uk (a constant giving the internal energy before or after the mixture) ... (2 mf + mg = mo (a constant) ....................... (3
As the gas or vapor condensed in the liquid is hotter and has a higher pressure than the liquid, heat is added to the liquid by the condensation of gas

 <Desc / Clms Page number 14>

 In this one. As a result, the pressure, temperature, mass and specific volume of the liquid rise.

   It is theoretically possible to predict the final state of liquid in a and gas in b as a result of the condensation of the second in the first. For this purpose it is necessary to know the initial conditions such as the mass, the pressure and the temperature of the gas and the liquid, the volume of the receptacles and the thermodynamic properties of the liquid and the gas, particularly the temperature. internal energy in function of pressure and temperature or volume.



   In general thermodynamic diagrams for different liquids have been prepared, which give a thermal quantity or thermal quantities as a function of what is called the volumetric variables p, t and v. For example, in the temperature-entropy diagram, lines of constant heat and pressure are usually given. In the total pressure-heat diagram, lines of constant temperature and constant entropy are given. It is important to note that the entropy and total heat functions are unique for any state of a substance.



  For example at any pressure and any temperature, a given fluid has one and only one value for entropy or total heat.



   Internal energy is also a function which is defined by the state of the substance. If a substance is changed by an operation from one state to another, the change in internal energy, entropy or total heat is path independent and has a defined value. In the present discussion the physical significance of these quantities is irrelevant. Yiathematically, they are functions which are employed to determine the pressure and temperature conditions which result in a liquid phase when a gas phase is condensed therein in oondi-

 <Desc / Clms Page number 15>

 conditions here imposed. Note that internal energy is a fundamental concept while total heat and entropy are derived.

   For an ideal gas, the change in internal energy is equal to the specific heat at constant volume multiplied by the change in temperature, while the change in total heat is equal to the specific heat at pressure finds that multiplies the temperature change. In other words, the internal energy relates to Cv just as total heat is to Cp.



  As the operations performed here involve constant volume relations, the function of internal energy is fundamental.



   The reduction in blast loss from an initial transfer vessel, by condensation in the next charge of liquid, is an advantageous result achieved by the use of the present cascade system. This is essentially a thermal operation. As with most thermal operations the physical possibilities and limitations of the system are determined from the heat and material balances. This balance, for the present cascade system, differs from that involving a constant flow when a material of the same characteristics can be flowing in the same direction at any time, since the vessels in the cascade system are successively loaded and unloaded.

   The heat balance for the present system, according to the first law of thermodynamics, from the above, gives the internal energy Uk of the system as constant for the equalization operation since there is no thermal or mechanical contact with the outside.



  For the material located in the a and b respectively, when passing from state (1) to state (2),
 EMI15.1
 equation (2) becomes Uk mP? + mui 1ùà% # + u ... (4 formula in which m is the mass of matter in the

 <Desc / Clms Page number 16>

 container a before legalization and u is the internal energy per unit mass in b after flow. The other terms use the symbols in an analogous way.



   The material balance, shown in equation (3) for the change of state in the two receptacles, with no material entering from the outside, becomes the same
 EMI16.1
 mZ m = m2 2 m: ............................... (5 By mla we mean the mass of matter in a before equalization This includes the weight of matter in both phases when two phases are present Similarly u1a is the average internal energy per unit mass so that m1au1a contains the internal energy of both phases.



   By calculating the energy available of the liquid in the system, for example that of liquid oxygen, it can be seen that the substance can be evaporated and made to compress into a relatively high pressure gas, without input of energy other than the heat of the gas. the surrounding space; this is accomplished by the present process without appreciable loss of material.



   In order to determine the available energy, we have recourse to the second law of thermodynamics, remembering that the total heat is, by definition, for any system:
I = U + Apv ..................................... (6 equation in which I denotes the o total heat, U denotes the internal energy and Apv denotes the work as a function of the units of heat determined by means of the volume v through which a piston moves at a pressure p, A being the reciprocal of the mechanical equivalent of the heat.



   By differentiating then equation (6) we have dI = dU + Apdv + Avdp ........................... (7 but by definition , according to the first law of thermodynamics, as we have indicated above, we have

 <Desc / Clms Page number 17>

 dQ = dU + Apdv or dI - AvDp.



   By the second law of thermodynamics and for a reversible process, this last expression is equal to the temperature (T) multiplied by the change in entropy (dS). By substitution we have TdS - dI - Avdp, and from there
Avdp = dI - TdS .................................... (8 We see that the quantity Avdp is positive for increasing pressure.



   The hypothesis of a strictly reversible process according to the second law of thermodynamics requires that the heat exchanges considered here are also reversible. In order to obtain the final reversibility, it is assumed that all the heat exchanges take place here under infinitesimal temperature differences, at the temperature of room 70 (taken here at 20 C or 293 K). This temperature for heat exchange is possible by assuming reversible adiabatic compressions or expansions as necessary to reach To. With this limitation, the last term of equation (8) becomes To dS.

   By integrating the two sides we have
 EMI17.1
 c / r $ àvdp = I 1 2 .z -i (S -S) ................... (9 1 in which we see that J kvdp is the work of an ideal reversible compressor or c / 1 of an expansion motor operating on a continuous flow and supplied by means of a fluid entering in state (1) and exiting in state (2). for the integral show the amount of work that can be obtained from the fluid by passing from one state to another. This is the available energy which is here called Q.

   Therefore
AT
 EMI17.2
 <L '1 - Il - 0 (Sa -al) ........................ (10 The available energy of one pound of oxygen liquid under pressure

 <Desc / Clms Page number 18>

 Atmospheric pressure, compared to one pound of gas at atmospheric pressure and 20 C can be found in tables currently published. Inequation (10), as a function of the British thermal units, then becomes:
QA = 173 - 0 - 293 (1.48 - 0)
 EMI18.1
 m a61 B.T.ü. / pound
Likewise the energy available from one pound of gaseous oxygen to. 2000 psi and 20 C for example is found to be - 160.3 B.T.U./lb.

   This value is less than the energy available in a pound of liquid and therefore it follows that a reversible frictionless device could use the energy available in the liquid to produce
 EMI18.2
 AOOO psi of gas to 2000 and at the same time discharge the excess energy available in the form of work. In any practical apparatus, certain losses are inevitable.

   The fact that the value for the available energy of -2000 psi of gaseous oxygen is less than that of the liquid shows that an apparatus can be established in which an available energy of the liquid oxygen is widely used to produce high pressure oxygen gas without doing any outside work or undergoing a significant loss of material and only requires the addition or removal of heat from the surrounding atmosphere. Various advantageous arrangements of apparatus which effect the removal and use of this heat are given below.



   The energy transfer from container b to container a, given above in equation (4), is graphically represented in an explanatory flow diagram according to 1 & fig. 6.



  In this case the energy initially found in the material in the container A is arbitrarily taken to be substantially equal to zero and is represented by the vertical line F drawn from top to bottom at the upper left and entering in the system which is represented by the rectangle

 <Desc / Clms Page number 19>

 envelopment; the movement of liquid is assumed to be from top to bottom while the movement of gas is shown from bottom to top. The amount of heat or internal energy carried is represented by the width of the currents. The current flow f of liquid first receives a large increase in energy from the gas transferred from vessel b, as shown by the flow ± arriving from the right.

   The unregulated heat introduction due to heat leaks etc. is represented by the current h entering the system from the left and joining the current from top to bottom. The controlled introduction of heat is represented by the large current k entering from the left. At the bottom, the departure of current 1, representing the internal energy of the output is shown and it takes away most of the thermal energy that has entered the system. Connected to the current from top to bottom, to the right in the system, there is shown a current m which represents the internal energy of the gas remaining in the final container b after the liquid has been evacuated and which flows from the bottom to up when transferred to the receptacle a.

   Most of the internal energy of the current from bottom to top is transferred to the left to form the ± current which joins the liquid stream f, while the remainder escapes from the system with the blowing, as shown in the current n exiting at the upper right end.

   In equilibrium, the sum of all thermal energy entering the system is equal to the sum of all thermal energy leaving the system. That is to say that we have: h + k = 1 + n - f ............................... . (11
The diagram in fig. 7 shows in an analogous way the mass balance of equation (5) and the flow of materials in a two-stage cascade system, the flow of the liquid being from top to bottom and the flow of

 <Desc / Clms Page number 20>

 gas from bottom to top as before, while the width of the stream indicates the amount by weight. The liquid stream enters at the top left, the width indicating the weight of a load.

   Blowing is represented by the flow leaving at the top right, having a width g indicating the weight of gas blown per charge.



  The weight of the discharge is represented by the width r of the stream leaving at the bottom. We see that the relation between these quantities is given by the following equation:
 EMI20.1
 p 8: q + r ..................... 8- ..................... ...................... (12
This equation simply states that the load is equal to the net discharge plus the net discharge. In the system the rising gas stream represents the gas transferred to vessel a from vessel b, the part which flows to the left to join the liquid stream being the condensed part, while the remainder comes out. at the top right as a blow-off.



   There is shown in FIG. 1 an industrial application using a transfer container arrangement applying the present method, in order to effect a transfer of liquid oxygen to an industrial consumer apparatus. Shown herein is the chassis of a motor vehicle which carries a supply vessel containing a supply of liquid oxygen at a relatively low pressure, which is to be supplied as gas to a consumer at a relatively high pressure. The container c is supported in an insulating envelope 26 which protects the liquid from unwanted heat input from the atmosphere.

   Near the receptacle o is arranged a casing 27 which contains a cascading system of receptacles arranged to effect the transfer of liquid oxygen from receptacle a to a high pressure evaporator, indicated as existing on the truck in a casing 28 and having an outlet or outlet connection

 <Desc / Clms Page number 21>

 e to serve a customer. The casing 27 is made substantially airtight so that the apparatus placed therein can be protected from the influence of the heat of the atmosphere by removing the air from the casing. or by filling the space not occupied by the apparatus with heat-insulating material.

   The reactor system within the casing 27 can be any cascade system according to the present invention, for example that shown in Figs. 2, 3, 4 or 5. More particularly, that shown as mounted on the truck in FIG. 1 is that of FIG. 5. The connection for liquid charging is shown at 10 in fig. 1; it goes from the bottom of the supply vessel c, has a device for measuring the liquid indicated at 10 'and passes into the top of an initial vessel designated by 73 in order to supply measured loads of liquid oxygen under relatively low pressure to the system.



   The transfer of liquid oxygen from the vessel to the serpentine d is accomplished by first causing a flow of liquid through communication 10 into the initial transfer vessel, which operates at the highest pressure level. low in the system. This flow can take place under the influence of a pressure built up in the container c, which is relatively low, for example five pounds per square inch, but exceeding that which prevails in the initial transfer container. The formation of this pressure in the supply vessel can be accomplished in any suitable manner, for example by means of an auxiliary evaporation coil such as 29 arranged as disclosed in the Heylandt patent. republished under n 1887 6 of June 20, 1933.

   The transfer of liquid from the supply vessel ± to the coil d can be done by any of the ex- cascade systems.

 <Desc / Clms Page number 22>

 posed below with regard to the description of FIGS. 2, 3, 4 and 5; the connection 10 for supplying liquid to the various series of apparatus shown being that shown in each of these figures. A cascade system thus arranged on an automobile truck and used to deliver desired quantities of regasified material to consumer devices in different places, exhibits very low net operating losses, by delivering gas at the desired pressures.



   There is shown in FIG. 3 a series of transfer pressure vessels 31, Sa and 33 each connected to a common general line 10 for charging the liquid phase through which liquid is supplied to each of the vessels 31, 32 and 33. These three receptacles are also connected to be opened by a general pipe by means of the exhaust duct 30. A common extraction duct 34 is provided communicating with each of the receptacles for the evacuation thereof, this duct ending in the coils. 35 of a high pressure evaporator. In this arrangement, the transfer containers are hereinafter referred to as connected in parallel. Although only three receptacles have been shown, it is obvious that four or more can be used.



   In order to equalize the pressures and temperatures in the containers before evacuating the liquid, a conduit 35 runs from the coils 35 and is connected by a general conduit 36a common to the gas spaces of each of the containers 31, 32 and 33, this connection being shown as produced by branch conduits 36 ', 36 ", 36"'. In duct 36 there is interposed a means of mechanically assisting the flow of fluid therein, which is here shown in the form of a centrifugal fan 37 having its inlet at 38 and its outlet at 39 and

 <Desc / Clms Page number 23>

 powered by an electric motor 40.

   The ventilator 37 provides, when activated, a pressure difference between the coils 35 and the vessel which is discharging, sufficient to accelerate the flow of liquid and oblige it to be lifted against a height. relatively low load. The coils 35 can therefore be arranged at any desired height above the lowermost part of the transfer containers. A means of connecting the receptacles to one another is also provided for introducing gas from one receptacle through the liquid of another.

   This means here comprises an independent duct 41 connected, by means of the branch duct 41 ', to the lower end of the receptacle S1, by means of the branch duct 41 "to the lower end of the repeater 32. , and by means of the branch pipe 41 "'at the lower end of the container 33. The connections to each of the containers are preferably controlled by valves. Accordingly, the communication of the link 1a with the container 31 is shown as controlled by the valve 42 ', while a valve 43' controls the connection with the opening duct 30. A valve 44 'controls the outlet. to the removal line 34, while a valve 45 'controls the connection 36' to the line 36.

   A valve 46t controls the branch 41 'ending with the conduit 41 and similar valves are associated with the vessels 32 and 33. A valve 47 is also shown controlling the outlet of the vaporization coil.



   In operation, the cycle of operations can be assumed to begin when the valves are closed, the vessels empty of liquid but containing gas, and the vaporizing coils filled with gas at a relatively high pressure. To start the system, the containers are successively filled with loads of liquid.

 <Desc / Clms Page number 24>

 extracted from pipe 10 by opening the corresponding valves controlling the general pipe; for example, container 31 is filled with a desired load by opening valves 42 'and 43'.

   The pressure of a container 31 is first equalized with that of an adjacent container which is full of gas, for example with a container 32, by the opening of the valves 46 'and 46 ", which has the effect of The result is a pressure in the receptacles 31 and 32 which is intermediate between that initially prevailing in the receptacle 31 and that in the receptacle 32, and a condensation of a part of the gas of the receptacle 32 in the liquid of the receptacle 1. When this first stage of equalization is accomplished, a second is carried out at somewhat higher pressure with another vessel, in this case with vessel 33, by opening valve 46 "after valve 46 "has been closed. When these intermediate equalizations are completed, a final equalization with coil 35 is effected by opening valve 43 '.

   Then the valve 44 'is opened and the fan 37 is turned on which creates a pressure difference which results in accelerating the flow of liquid from the transfer vessel into the evaporator. tor. When all the liquid has been discharged, the vessel 31 is filled with gas having a pressure equal to or slightly higher than that of the evaporator.



   The practice of thus effecting the equalization in several stages before that finally achieved before the draining produces a greater amount of condensate from the gas phase than could otherwise be obtained, as in each case. stage of the intermediate equalizations, a succession of pressures is applied, each of which makes available a new condensing capacity of the liquid, because each higher pressure applied to the

 <Desc / Clms Page number 25>

 liquid raises the boiling point and makes more use of the condensing capacity, which uses the available energy of the liquid in a very efficient manner.



   While the container 31 is unloading, the container 32 will be filling, so that upon completion of the evaporation it can be leveled first with the container 33 and then with the container 31. It is seen. therefore that the removal of the gas phase from each container takes place at several pressures such that a relatively low pressure remains in a container when it is finally blown for the admission of a new charge.



   Fig. 4 shows an arrangement of transfer pressure vessels partly in series and partly in parallel, by means of which relatively rapid discharge can be effected and relatively continuous operation of the evaporator can be maintained. In this figure, 48 denotes a coated pressure vessel disposed above a second coated pressure vessel 49 and intended to deliver liquid therein; there are, in addition, two receptacles 50 and 51 communicating with a general pipe 52 for transferring the liquid from the receptacle 49. The thin metal casing or the basket 48 'of the receptacle 48 appreciably retards the flow of heat. thick walls of the pressure vessel in the liquid charge placed in oelui-oi.

   Starting holes in the upper part of the baskets provide pressure equalization with the space between the basket and the walls of the pressure vessel. This space can be maintained by the fact that the basket is supported by means of strips of material with low thermal conductivity, which promotes the desired effect of thermal insulation and allows the transfer to take place under conditions approaching those of Ideal adiabatic conditions desired.

   These oommu-

 <Desc / Clms Page number 26>

 also connect at their lower end with a common general duct 53 for discharging the liquid which leads to the evaporator 54. A gas connection means 55 between the evaporator and the containers 50 and 51 has connections 55 'and 55 "connecting respectively to the gas space of the vessels 50 and 51. An equalizing duct 56 protrudes into the vessel 49, almost reaches the top of the latter and has branches 56 'and 56" communicating with the gas space of the receptacles 50 and 51, respectively.



    A similar conduit 57 is disposed so as to extend from the gas space of container 49 to the top of container 48. An outgoing conduit 58 runs from the top of container 48 and is controlled by a valve. valve 59. A valve 60 is disposed in conduit 10 to control the inlet. A valve 61 controls the connection through which the container 48 delivers liquid into the container 49, a valve 62 controlling the communication 67. Valves 63 'and 63 "control the inlets respectively to the containers 50 and 51 in the general pipe. discharge valve 52. Likewise, valves 64 'and 64 "control the outlet connections to the removal line 53.



  Valves 65 'and 65 "respectively control the communication of the connections 55' and 55" with the conduit 55.



  Valves 66 'and 66 "similarly control the downstream branches 56' and 56" of conduit 56 which enter vessels 50 and 51 respectively.



   In order to condense the gas from the container 49 into the liquid contained in the container 48, a conduit 67 controlled by a valve 68 is arranged to extend from the gas space of the container 49 into the lower part of the chamber. the liquid space of the container 48, where it is provided with suitable means for distributing the gas in the liquid, for example a distributor 67 'having a number of small openings.

   This way produces rapid condensation and

 <Desc / Clms Page number 27>

 extent of gas passing from one container to another; similar means are provided for effecting a cross-level equalization between the receptacles 50 and 51, in the form of a distributor connected to a duct 69 comprising a control valve 70. This duct connects the lower parts of the spaces between them. liquid from both containers when valve 70 is open.



   The flow of liquid through line 55 into the evaporator 54 is accelerated and is effected against a pressure height caused by the arrangement of the evaporator, by means of a rotary pump 71 having its inlet connected to line 53 and its exhaust communicating with the evaporator. The pump is mechanically powered by any desired means, which is shown in the drawings as an electric motor 72.



   In operation, the cycle of operations which normally takes place can be assumed to begin when the coils 54 are full of high pressure gas and the valves are closed. The container 48 is filled through the opening of the valves 59 and 60 to admit a determined quantity of liquid, a desired gas space being kept at the top of the container 48 to prevent overflow of the basket 48 'and to allow the subsequent relaxation. When filling is complete, the valves are closed again and the pressures in the vessels 48 and 49 are then equalized.



  This is done by opening the valve 68 so that the gas in the vessel 49, which is at a higher pressure, bubbles through the liquid in the vessel 48 with condensation of a significant portion of that gas. When the equalization is substantially complete, the liquid in the container 48 can be rapidly sent to the container 49 through the opening of the valves 61 and 62, after which the valves 61, 62 and 68 are closed. The liquid can then

 <Desc / Clms Page number 28>

 be transferred from container 49 to container 50 through the opening of valve 63 '.

   This is accomplished by allowing gas at elevated pressure to first flow from vessel 50 and to bubble through the liquid in vessel 49 through conduit 52 until substantial equalization results. , after which the valve 66 'is opened to quickly complete the transfer of liquid to the container 50. When the container 50 is filled, the valves 63' and 66 'are closed and the valve 70 is opened so that 'there is a cross-level equalization stage of the receptacles 50 and 51 before the filling of the latter takes place, part of the gas which remained in the receptacle 51 of a previous operation flowing through the conduit 69 in the liquid of the reoipient 50 to be partially condensed by the latter.

   After closing the valve 70, the receptacle 50 is emptied into the coils 54 by opening the valves 64 'and 65' and starting the pump 71: which applies a sufficient mechanical force to force the material to flow against the head due to the elevation of the evaporator. The valve 23 'is open when the discharge to the receiving apparatus occurs.



   Depending on the degree of heat input, vessel 50 is usually discharged relatively slowly to the evaporator so that vessel 48 cannot only be recharged for the start of a new cycle, but charging can. be transferred to the container 49 by repeating the operations described above. Upon completion of the refill of the container 49, while the container 50 is still discharging, the container 51 can be filled. Accordingly, valve 63 "is opened to effect gas condensation and substantial pressure equalization, after which valve 66" is opened and transfer is complete.

 <Desc / Clms Page number 29>

 



   At this time, the container 50 is empty of liquid but filled with gas at a relatively high pressure. Cross-equalization is then effected by opening the valve 70, the flow being from the container 50 into the container 51. When the valve 70 is again closed, the container 51 is then discharged to the coils 54 by. opening of the valve 64 "and of the valve 65" and actuation of the pump 71, the cycle being continued by the alternate reloading and unloading of the receptacles 50 and 51 and those combined therewith, as described above. oi above. In this way, a substantially continuous operation of the evaporator device is obtained.



   In fig. Provision has been made for an installation comprising containers designated 73 ', 73 ", 74', 74" and 75, respectively, arranged partly in series and partly in parallel. The vessel 75 is here constructed to be of a different nature from the first-mentioned vessels so that a certain amount of heat can be supplied to the contents thereof, under certain conditions, during discharge to the vessel. evaporator, as is indicated in more detail below. In the arrangement shown, the receptacles 73 'and 73 "are connected in parallel by a common general pipe to receive charges of liquid from the pipe 10.

   The container 73 'is arranged to discharge the liquid under the effect of gravity into the container 74' which in turn is established to discharge the liquid into the container 75. In a parallel fashion, the container 73 is set to discharge into container 74t 'which in turn discharges into container 75. Container 75 is thus a common container interposed between a heating coil 76 of evaporator d and the two groups. of receptacles in series 73 ', 74' and 73 "-74". The receptacles 73 'and 73 "are emptied by

 <Desc / Clms Page number 30>

 blowing by means of a common general pipe 77.



  The evaporator d discharges through a pipe 78 leading to the outlet e. Connections 80 'and 80 "lead the discharge from receptacles 73' and 73 'to receptacles 74' and 74", respectively. Likewise connections 81 'and 81 "discharge from containers 74' and 74" into the upper part of container 75. Removal conduit 82 goes. from the bottom of the container 75 to the coil 76.



  An equalization connection 83 leaves from an intermediate point in the coil 76 and has branches 84 and 85 respectively going to general conduits communicating with the receptacles 73'-74 'and with the receptacles 73 "-74. ". Communication conduits are also provided for the cross-equalization of the pressures between corresponding receptacles on the two sides of the connections in parallel. These cross connections are shown at 86 and 87, the connection at 86 connecting the lower parts of the containers 73 'and 73 "while the connection 87 connects the lower parts of the containers 74' and 74".

   In this arrangement, a check valve 88 is preferably introduced into the conduit 78 to provide flow in a direction in the conduit to the outlet e.



  A connection 89 is also provided running from a point in the conduit 78 beyond the valve 88 to the top of the container 75, a valve 90 being disposed to control this latter connection. A bypass is also preferably provided between conduits 83 and 89, as shown at 101, and is controlled by valve 102. Valves 91 'and 92' respectively control the liquid inlet connections and. starting point of the receptacle 73 '. A valve 93 'controls the connection 80' and a valve 94 'controls the connection 81'.

   A valve 95 controls the connection 82 to the vaporizer coil.

 <Desc / Clms Page number 31>

   The valve 96 'controls the communication between the upper parts of the containers 73' and 74 'while the valve 97' controls the connection of the container 74 'with the conduit 64. The cross-equalizing connection 86 is omitted. driven by valve 98, while cross-leveling connection 87 is likewise driven by valve 99.



  Valves 91 "and 92" are similar to valves 91 'and 92' and control the inlet and outlet connections of receptacles 73 ", with valves 93", 94 ", 96" and 97 "being arranged so analogous to the containers 73 "and 74" and performing the same functions as the valves 93 ', 94', 96 'and 97' respectively.



   In operation, the cycle of operations which normally occurs will be assumed to begin when the initial vessels are empty and the evaporator d and vessel 76 are full of gas at a relatively high pressure.



  Before filling, the system is first purged of air through the opening of valves 96 'and 97' and 96 "and 97", with valves 96 'and 96 "being closed before the pressure has equalized. into coils 76 and vessels 73 ', 74', 73 "and 74". When the system is thus ready, liquid is introduced into vessel 73 'through the opening of valves 91' and 92 '. has blown off all the gas contained in the container 73 "by means of the pipe 77, the valve 98 is first opened so as to allow the exit of a little gas through the connection 86 of the container 73" in the receptacle 73 ', to be condensed in the liquid thereof.



  On opening valve 93 'gradually, the gas in vessel 74' rises through the liquid in vessel 73 ', some of it condensing until the pressures equalize, after which the gas in vessel 73'. Liquid is sent directly from vessel 75 'to vessel 74', the flow being produced through the opening of valve 96 '. This passage of liquid has

 <Desc / Clms Page number 32>

 preferably while container 73 "is being filled. Therefore, as soon as valve 98 is closed, valves 91" and 92 "are opened.



   When the container 74 'is filled, and before the filling of the container 74 "commences, a cross-leveling is effected between these latter containers by closing the valves 93' and 96 'and opening the valve 99 in. connection 87. When this equalization is completed and valve 99 is closed, valves 94 ', 97' and 102 can be opened and an exchange of gas and liquid takes place between vessels 74 'and 75, the displaced gas flowing upwardly through conduits 101, 83 and 84. In this arrangement, the filling of receptacle 74 'from receptacle 73' and that of receptacle 73 "from connection 10 takes place substantially. simultaneously.

   The opening of the valve 94 'is therefore accompanied by the opening of the valves 91' and 92 'to refill the container 73' and blow into it while the container 74 "is at the same time filled from the. receptacle 73 "through the opening of valve 93" first and finally of valve 96 ".



   Container 75 is of course filled from container 74 'upon completion of the above-indicated filling operation and after cross-equalization of the pressure in containers 74' and 74 "has been completed. effected by opening the valve 99. The container 75 is then discharged to the coil 76 through the opening of the valves 95 and 102. When the charge of the container 75 has been completely discharged, the valves 95 and 102 are de-energized. closed again and the vessel is reloaded from vessel 74 "to be ready for further discharge to the evaporator.



   It can be seen from the arrangement shown that the liquid is admitted into the receptacles always by

 <Desc / Clms Page number 33>

 diagonally opposite ooins of the quadrilateral formed by the four containers 73 ', 74', 73 "and 74". It can also be seen that the cross-equalization effected by the opening of the connections 86 and 87 produces an oondensation of gas sent through the liquid, in addition to that effected before the exchange of liquid and gas, this is ie in the series-parallel arrangement shown there are four separate oondensation operations in the transfer of a liquid charge from receptacles 73 'to 75 or receptacles 73' to 75, the gas passage being countercurrent to increases in pressure on the liquid.



   The thick-walled container 75 performs an additional function when the charge it contains must be vented at or above the critical pressure. When the heating coil 76 supplies gas at a pressure significantly above the critical pressure, for example oxygen at 2100 pounds per square inch, the material in the container 75 passes through the critical temperature before that it is completely discharged by the valve 95. When the critical temperature is reached, the flow under the influence of gravity becomes very difficult since there is no longer a clear separation of the phases.

   It is desirable to force this gaseous material out of vessel 75 by causing it to expand as a result of an increase in its temperature, which expansion may be effected by the advantageous addition of gas. heat to the material in the container 75, for example by the application of a heating fluid such as steam in heat exchange relation with the walls of the container 75, by means of a conduit 100 arranged in rela - tion of thermal conductivity with the wall of the container 75. This forces the gaseous material in the container 75 to heat up with, consequently, an expansion which pushes back

 <Desc / Clms Page number 34>

 material quickly out of the container.

   Normal flow through valve 95 continues to the evaporator coil which acts as a heater to raise the temperature of the gas and superheat it. The check valve at 88 is, as can be seen, a suitable means of preventing backflow of the line into the evaporator so long as the initial pressure equalization with that in vessel 75 takes place. The gas connection 89 serves to supply gas directly from the line to the vessel 75 when it is desired to withdraw liquid to feed the vaporization coil immediately, without waiting for the pressure to rise to the line pressure. by heat input.



   It can therefore be seen that the arrangement of FIG. 5 provides an apparatus for effecting the conservation of displaced gases, to a high degree, by limiting the blowing to a relatively low value, while at the same time supplying vaporized liquefied gas to industrial consumers, at pressures in excess of critical pressure, with the servioe being performed in relatively short periods of time.



  When the series of containers are established by means of sufficiently small units, the arrangement is easily capable of being mounted and housed on a truck, as shown in fig. l, to serve industrial consumers, which may be relatively large distances from a central production facility.



   The cascade system according to the present invention is also employed in fixed installations, for example to serve consumer devices containing piping connecting several users to a gaseous material under a desired pressure from a low storage vessel. pressure containing the liquefied gas, and for filling containers at the product installation

 <Desc / Clms Page number 35>

 liquefied gas generation, in which case the liquefied gas can be received directly from the production apparatus and the gas evacuated from the initial vessel can be returned to the production apparatus for reliquefication.



   In cases where the liquid supply source is located above the initial transfer vessel, it is envisioned that gas discharged from the initial vessel at the start of a cycle may be conducted into the supply vessel. to facilitate the flow of liquid.



   Although the device which has been shown in the various views as receiving the gaseous material from transfer vessels operating according to the cascade principle has been described as an evaporator comprising heating coils, it goes without saying that the receiving device can have many other forms; for example it may comprise one or more containers containing liquid, or gas storage cylinders or gas heating containers.



   As certain changes may be made in the practice of the above process and in the disclosed constructions which embody the invention without departing from the essence of the invention, it should be understood that all which is set forth in the foregoing description or is shown in the accompanying drawings should be interpreted as being given in an explanatory sense and not in a limiting sense.


    

Claims (1)

SUMMARY ----------- 1. A method of transferring a volatile liquid material which has a gas phase produced as a result of the heat obtained in the transfer, from a region of relative pressure- low pressure to a region of relatively high pressure, which process comprises the features of causing the material to pass in succession through the material. <Desc / Clms Page number 36> charges measured, in countercurrent with respect to the gas phase, to substantially exclude any heat of external origin of the material before passing through a determined point, and to use the available energy of the liquid material to condense a part of the gas phase so that the final loss of material in the gas phase is significantly reduced. 2. A method of transferring a volatile liquid material which has a gaseous phase produced as a result of the heat obtained in the transfer from a region of relatively low pressure to a region of relatively high pressure. which includes the characteristics consisting in causing the passage through the material, in a succession, of measured charges, in countercurrent with respect to the gas phase by a succession of stages of acute pressures, to substantially exclude any heat from external origin of the material before passing to a determined point, to use the successive increase in condensing capacity made available by the increased pressure in these stages to condense a relatively large part of the gas phase in the liquid phase, and in increasing the liquid phase which passes by adding thereto this condensate, so that the internal energy of the gas phase is reduced appreciably during its passage in countercurrent with respect to the advancement of the gas. liquid. 3. A method of transferring a volatile liquid material which has a gas phase produced as a result of the heat gained in the transfer from a region of relatively low pressure to a region of relatively high pressure. from one container to another in cascade, a method which comprises the features of forcing a series of measured charges of liquid to pass under the influence of a gravity field from one container to another. <Desc / Clms Page number 37> a relatively low pressure in a relatively high pressure vessel, while the gas phase is displaced and passes in the opposite direction to this in a heat exchange relationship therewith, to convert part of this gas phase in liquid phase and adding the latter to the transferred liquid, so that the final final material loss in the gas phase is substantially reduced. 4. A process of transferring a volatile liquid material, which has a gaseous phase produced as a result of heat gained in the transfer, from one container to another in a cascade, which process includes the features to be introduced. a measured load of material in the liquid phase in one vessel while another vessel contains material in the gas phase at a relatively high pressure, to equalize the pressures between these vessels while effecting condensation of the gaseous material extracted from the vessel at high pressure, at the expense of the energy available in the liquid phase, to then pass the liquid material into the other vessel and to substantially exclude any external heat from the material during this passage. 5: A method of transferring a volatile liquid material, which has a gaseous phase produced as a result of heat gained in the transfer, from one container to another in a cascade, which method includes the features to be introduced. a measured load of material in the liquid phase in one vessel while another vessel contains material in the gas phase at a relatively high pressure, to equalize the pressures between these vessels while effecting condensation of the gaseous material extracted from the high-pressure vessel and pass it into the low-pressure vessel, and to be exchanged, under <Desc / Clms Page number 38> the influence of gravity, the liquid and gaseous phases between these vessels. 6. A process for transferring a low boiling point liquefied gas which produces a gas phase as a result of heat gained in the transfer from a relatively low pressure supply vessel to a reactor. at a relatively high pressure, which comprises the characteristics of effecting the passage of a measured charge of liquefied gas from the supply vessel, in a cycle, through regions of successively increasing pressures until the desired high pressure is obtained, to effect a countercurrent passage through the material in the gas phase with the liquefied gas while passing it from the region of the low pressure to the. high pressure region, so that a major part of the gas phase is condensed, substantially excluding heat of external origin during this passage and venting substantially reduced gaseous material to air from the low pressure region at the start of a cycle. 7. A process for discharging a gaseous material which is received in the liquid phase but has a gaseous phase produced as a result of the addition of heat, into a receiving vessel by spontaneous compression, which process comprises the features of separating masses of liquefied gas, to discharge a desired part of one of these masses into the receiving vessel by moving the mass of liquefied gas with gas having a relatively high pressure, to produce this gas by transferring under the action of 'a force of external origin on this mass in thermal contact with a heat source, and distributing the internal energy of the gas used to effect the displacement among a number of other separate masses of liquefied gas <Desc / Clms Page number 39> before moving the massagers to the containers, so that the energy available from the liquid phase is used to recover some of the material in the liquid phase. 8. A method for discharging a gaseous material which is received in the liquid phase but has a gas phase produced by the addition of heat, to a receiving vessel, by spontaneous compression, which method comprises the characteristics of providing a separate mass of liquefied gas, to force desired portions of this mass to pass through successive stages of oroissant pressure by displacement with gas under the influence of gravity, then to force these portions to come into thermal contact with a source of heat and to distribute the internal energy of the gas used to move these parts in successive portions, so that the available energy of the liquid phase is used to re-cut some of the material in the gas phase. 9. A process for providing gaseous material which is received in the liquid phase but has a gaseous phase produced by the addition of heat to a receiving vessel at a specified pressure greater than atmospheric pressure, which process comprises the characteristics oonsisting in isolating a charge of liquefied gas in a receptacle belonging to a certain number of transfer receptacles, into which it has been introduced under a pressure less than this determined pressure, in raising the pressure of this load to a value exceeding the pressure determined, by the discharge of this charge under the influence of a force of external origin through a heated region, to heat and vaporize this charge, to discharge a desired part of it towards the receiving vessel, so that a residue of the gas phase is left in this container <Desc / Clms Page number 40> transfer with a pressure equal to the determined pressure, to isolate a charge of liquefied gas introduced at a pressure lower than the determined pressure in a second transfer vessel, where it is kept substantially isolated from the input of heat for a desired period of time, and driving a portion of the gaseous residue from the first charge into that second charge so that a portion of that gaseous residue is condensed and increases this second charge as the pressure of the residue is reduced , and to complete the cycle by transferring this second charge to the intermediate container mentioned first. 10. A method of transferring a liquefied gas which is volatile at normal atmospheric pressure and to a gas phase produced from a supply vessel, where. it is maintained at a relatively low pressure and temperature, to a receiving vessel at a relatively high pressure and at an elevated temperature, by means of transfer vessels arranged in cascade and enclosing an evaporator vessel. which comprises the features of delivering a measured charge of liquefied gas from the supply vessel into a vessel selected from among such transfer vessels while another contains gas at a higher pressure, to reduce the pressure difference between these receptacles by effecting a heat exchange between the liquid in the chosen container and the gas, so that part of this gas is condensed, and to discharge the gaseous matter under the influence from a force of external origin towards the receiving vessel against a relatively high pressure from the selected vessel, while substantially excluding any heat of external origin before the evaporating vessel. 11. A method of transferring a liquefied gas from a supply vessel, in which it is maintained at a temperature. <Desc / Clms Page number 41> relatively low pressure and temperature, to a receiving vessel at relatively high pressure and elevated temperature, by means of transfer vessels arranged in cascade and enclosing an evaporator vessel, a process which includes the features of delivering a measured charge of liquefied gas from the supply receptacle into a receptacle selected from among transfer receptacles while other transfer receptacles contain gas at successively higher pressures, to reduce the pressure difference between the chosen receptacle and the other receptacles by effecting a heat exchange between this charge and the gas of the other receptacles successively, so that parts of this gas are condensed, in combining the gas parts condensed with liquefied gas to be transferred and discharged against a relatively high pressure of the gaseous material from this selected container to the receiving vessel by flow of the liquefied gas under the influence of a force of external origin towards the evaporator with resulting equalization of gas pressure, at relatively high pressure, between this selected vessel and the evaporator. 12. A method of transferring liquefied gas from a supply vessel, in which it is maintained at relatively low pressure and temperature, to a receiving vessel at relatively high pressure and elevated temperature. , by means of transfer vessels arranged in cascade and enclosing an evaporator vessel, a method which comprises the features of delivering a measured charge of liquefied gas from the supply vessel into a vessel selected from among transfer vessels. - fert while other transfer vessels contain gas at successively higher pressures, to reduce the pressure difference between the chosen container and the other containers by leading gas successively to <Desc / Clms Page number 42> higher pressures of the other transfer vessels in the liquid charge located in the chosen vessel, so that parts of gas are condensed and combined with that charge, and to discharge against a relatively high pressure of the gaseous material from that chosen vessel to the receiving vessel by flow of the liquefied gas under the influence of a force of external origin towards the evaporator, with resulting equalization of the gas pressure, at relatively high pressure, between the chosen vessel and the evaporator. tor. 13. A method of transferring a gaseous material which has a boiling point significantly below 273 K, from a region of relatively low pressure to a region of relatively high pressure, which method comprises the features of: characteristics consisting in isolating a measured charge of the material in the liquid phase in an initial transfer vessel of a series chosen from a group of series which are arranged in parallel, increasing the pressure of this isolated charge in stages , in preparation for the transfer to a next vessel of the chosen series by transferring first into this charge internal energy from the gas phase in a higher pressure vessel in parallel with this chosen series, and then effecting a new transfer of internal energy from the gas phase in the next vessel, and then discharging this material when it is at a desired high pressure. 14. A method of transferring a gaseous material which has a boiling point significantly below 273 K, from a region of relatively low pressure to a region of relatively high pressure, which method comprises the following methods. - characteristics of isolating a measured charge of the material in the liquid phase in an initial transfer vessel of a series selected from a group of series which are <Desc / Clms Page number 43> arranged in parallel, to increase the pressure of this isolated load in stages, in preparation for transfer to a next container of the series chosen by first equalizing the pressure of the material in the gaseous phase between the filled container and a vessel at a higher pressure in parallel with the chosen series, and then effecting pressure equalization in a next vessel of the series selected, increasing the charge of liquid transferred by adding condensate thereto and discharging this material when it is at. the desired high pressure to a common receiver. 15. A method of transferring a gaseous material which has a boiling point significantly below 273 K, from a region of relatively low pressure to a region of relatively high pressure, which method comprises the characteristics of not being isolated. a measured load of the material in the liquid phase in an initial transfer vessel of a series chosen from a group of series which are arranged in parallel, to increase the pressure of this isolated load in stages, in preparation for transfer to a next container of the series chosen by first effecting a countercurrent passage of the material in the gas phase of a container at a higher pressure in parallel with this chosen series, and then effecting a new countercurrent passage of material in the gas phase of the next vessel of the series chosen, such that a partial condensation of the gaseous material is effected in stages, to increase the charge of liquid transferred by the addition of the condensate thereto, to substantially exclude any heat of external origin during this transfer and these equalizations before a determined point, and to unload this increased charge when it is at a desired high pressure to a common receiver. <Desc / Clms Page number 44> 16. A method of supplying gaseous material to a receiving vessel at a predetermined pressure greater than atmospheric pressure, which comprises the features of isolating a measured charge of the liquefied gas in a vessel from among a number of transfer vessels. , in which it has been introduced under a pressure less than this determined pressure, to raise the pressure of this load to a value exceeding the determined pressure, by the flow of this load under the influence of a force mechanics of external origin through a heated region to heat and vaporize this charge, in discharging a desired portion of this charge to the receiving vessel leaving a gas phase residue in the transfer vessel with a pressure value equal to the determined pressure, in isolating a second charge of liquefied gas introduced at a lower pressure as the pressure determined in a second transfer vessel where it is maintained substantially isolated from the input of heat for a desired period of time, and to conduct a portion of the gaseous residue of this first charge into the charge seoon, so that part of the gaseous residue is condensed in the second charge and increases the latter as the pressure of the residue is reduced. 17. A method of transferring a low-boiling liquefied gas from a supply vessel at relatively low pressure to a receiver at relatively high pressure, which includes the characteristics required to pass. a considered charge of liquefied gas from the feed container in a cycle passing through regions of successively higher pressures until the desired high pressure is reached, to effect an exchange of gaseous material in the liquid phase with the <Desc / Clms Page number 45> gaseous matter in the gas phase at a higher pressure, equalizing the gas pressure in regions of relatively different pressures by transferring the gaseous material to the low pressure region through the liquid material so that partial oondensation of the gaseous material in the liquid phase is achieved , and allowing gaseous material to escape into the gas phase of the region of lower pressure at the start of a cycle. 18. A method of transferring a low boiling point liquefied gas from a supply vessel at relatively low pressure to a receiver at a relatively high pressure, which includes the following characteristics. passing a measured charge of liquefied gas from the supply vessel through a series of liquid sluices at successively higher pressures until the desired high pressure is reached, accompanying the passage of liquefied gas through each lock at a higher pressure of an eohange of gaseous material in the gas phase and to transfer to the liquid phase the internal energy of this gaseous material in the gas phase by a partial conversion of the gas phase into the liquid phase. of, so that at the moment of the coexistence of the gas and liquid phases in equilibrium, the internal energy of the liquid phase is at a maximum and the internal energy of the coexisting gas phase is at a minimum. 19. A method of transferring a low boiling point liquefied gas from a supply vessel at a relatively low pressure to a receiver at a relatively high pressure which comprises the features of passing a relatively high pressure. measured load of liquefied gas from the supply receptacle through a series of liquid sluices at successively higher pressures until the desired high pressure is reached, to accompany the passage of <Desc / Clms Page number 46> liquefied gas in each lock at a higher pressure from an exchange of gaseous material into the gas phase in a manner which effects a partial conversion of the gas phase to the liquid phase, to complete this exchange, when desired, without conversion of the gas phase to the liquid phase and to accompany this exchange of gas and liquid by an exchange of gaseous materials in the gas phase at relatively different pressures, so that the conversion. Additional gas phase to liquid phase is accomplished. 20. A method of transferring a low boiling point liquefied gas from a relatively low pressure feed container to a relatively high pressure receiving container which comprises the features consisting in passing a measured charge of liquefied gas from the supply vessel through a series of liquid sluices at successively higher pressures until the desired high pressure is reached, accompanying this serial passage of the gaseous material in the liquid phase of an exchange of gaseous material in the gas phase in the liquid locks, to transfer the gaseous material from the lock at the highest pressure to a receiving vessel and to accompany the admission of a new charge to the liquid locks with an evacuation by blowing of the gaseous material in the phase gas leaving the lock at the lowest pressure. 21. A method of transferring a low boiling point liquefied gas from a supply vessel at relatively low pressure to a receiving vessel at relatively high pressure, which comprises the features of: begin a cycle to effect the transfer by passing a measured charge of liquefied gas from the supply vessel into a liquid sluice when it- <Desc / Clms Page number 47> is at its lowest pressure, to carry out other transfers of the charge of this lowest pressure through locks at higher pressures with a countercurrent passage of the gaseous material into the gas phase accompanied by a partial conversion of the gas phase to the liquid phase, until the critical temperature and pressure of the gas material are reached, converting the gaseous material at the critical pressure and temperature to a homogeneous material phase by supplying heat in sufficient amounts to effect the desired expansion, and then further heating the gaseous material in a high pressure receiving device. 22. A method of transferring liquid oxygen from a supply and transport vessel at a relatively low pressure to a receiving vessel at a relatively high pressure, which comprises the features of passing a pressure. measured charge of liquid oxygen from the supply vessel through a number of pressure vessels in series until the desired high pressure is reached, to accompany the passage of this charge of gaseous material displacements into the phase gas from a relatively high pressure vessel to a lower pressure vessel, in such a way that there is a partial conversion of the gas phase to the liquid phase at the same time as a transfer of gas. internal energy from the gas phase to the liquid phase, transferring the charge from the higher pressure vessel to the receiving vessel without substantial phase conversion, and placing the lower pressure vessel in communication with the open air for receiving a new charge. 23. A method of transferring liquid oxygen from a transport vessel by means of associated vessels arranged in cascade, which method includes the characteristics <Desc / Clms Page number 48> consisting in transporting a receptacle containing liquid oxygen to a place of consumption, in discharging the liquid oxygen from this receptacle unimpeded, in a succession of charges, through these associated receptacles, and in discharging the charges to a receiving receptacle fixed, in an amount sufficient to fill this receiving receptacle to a defined pressure. 24. A method of transferring liquid oxygen from a transport vessel by means of associated vessels. cascaded, a method which comprises the features of charging a thermally insulated transport container with a mass of liquid oxygen which is maintained at a relatively low pressure and discharging the liquid oxygen therefrom through the associated receptacles towards a receiving receptacle, in a succession of measured charges, and in passing the gas contained in this receptor receptacle thereof, in counter-current with respect to the liquid admitted into the receptor receptacle. 25. A method of transferring liquid oxygen from a transport vessel, by means of side-by-side transfer vessels arranged in cascade, to a receiving vessel normally operating at relatively high pressure, which method comprises the features of conveying a separate mass of liquid oxygen in this transport container to a place of consumption, discharging liquid oxygen from this transport container in a series of charges through stages of increasing pressure towards the receiving vessel, to cause the gas contained in this receiving vessel to pass in countercurrent to the liquid passing through the transfer vessels, so that condensation of the gas into liquid is effected to increase the discharged liquid , while the receiving container is filled to a determined pressure. 26. A process for transferring a precious volatile liquid <Desc / Clms Page number 49> The process of moving from a transport container to a stationary receiving container, which method comprises the features of interposing a number of transfer containers, which can be communicated between the transport container and the receiving container, to to discharge a measured charge from this transport container to a chosen transfer container, to discharge the liquid content of this chosen transfer container, by displacement by means of gas admitted from another container at a higher pressure, to be condensed at minus a part of the displacement gas during the interim discharge, to add the resulting condensate to the discharged liquid and to remove the external heat from the discharged liquid, which may have entered the liquid in any of the transfer vessels. 27. In a cascade system of the kind described, the combination with a number of cascading vessels, intended to receive a liquid material capable of producing a gaseous phase, means to introduce a determined charge of liquid material from the supply container into a container while it is at a relatively low pressure, means for introducing gas into that container from another container at a higher pressure, such means for introducing gas into that container from another container at a higher pressure. - gas troduotion being arranged so as to effect a condensation of at least a part of the gas phase in liquid matter, and means using a force of external origin to cause an unloading of liquid matter towards receiving vessels. 28. In a cascade system of the kind described, the combination with a number of cascading vessels for receiving liquid material capable of producing a gas phase means selecting a vessel from an initial pair of vessels. low-pressure transfer vessels and introduce a determined charge of liquid therein <Desc / Clms Page number 50> from a low pressure supply vessel, means to equalize the pressure between this chosen vessel and the other of the initial pair, means for exchanging gas and liquid between this first initial transfer vessel selected and a container of an intermediate pair of containers and means for discharging the gaseous material from a container selected from these intermediate containers to an evaporation container. 29. In a cascade system of the kind described, the combination with a number of cascaded vessels for receiving liquid material capable of producing a gas phase, means of selecting a low pressure vessel and to introduce a determined charge of liquid therein coming from a supply container, means to equalize the pressure between this chosen container and another chosen container at a relatively high pressure through the material passage in phase. gas in relation to heat exchange with the material in the liquid phase contained therein, and means for moving the material in the liquid phase from this selected container, by the application of forces of external origin on the liquid. 30. In a cascade system of the kind described, the combination with a number of cascade vessels for receiving liquid material capable of producing a gas phase, means of selecting a low pressure transfer vessel and of 'introducing a measured charge of liquid therein from a supply vessel, means of equalizing the pressure between that selected vessel and another transfer vessel at a relatively high pressure, by the passage of gaseous material therein in heat exchange relation with the liquid material contained therein, and by means operating under the influence of gravity to send this charge <Desc / Clms Page number 51> to a receiving vessel. 31. In a cascade system of the kind described, the combination with a number of cascade vessels intended to receive liquid material capable of producing a gaseous phase, means of introducing a measured charge of liquid into one of these vessels , means of equalizing the pressure between this first container and a container chosen from among the remaining containers by the passage of gas from this chosen container to the first container, means of causing an exchange of gas and liquid between the first container and the selected containers. 32. In a cascade system of the kind described, the combination with a number of cascaded receptacles intended to receive liquid material capable of producing a gaseous phase, means of introducing a measured charge of liquid into one of these receptacles. , means of equalizing the pressure between this first container and a container chosen from among the remaining containers by the passage of gas from this chosen container to the first container, means of causing an exchange of gas and liquid between the first container and the selected containers, means to equalize the pressures between these remaining containers, means for discharging a desired portion of gaseous material from that selected container to a receiving container. 33. In a cascade system of the kind described, the combination with a number of pressure transfer vessels each arranged to receive a measured charge of a volatile liquefied gas, means for withdrawing liquid from each of these vessels. , means for effecting an exchange of gas and liquid, combined with certain pairs of these receptacles, means for effecting pressure equalization with this exchange and means for effecting a cross-equalization of gas between other pairs of these receptacles, the latter means being arranged so as to pass <Desc / Clms Page number 52> gas through the liquid and to effect partial condensation of the gas phase in the liquid phase. 34. In a cascade system of the kind described, the combination with a number of pressure transfer vessels each arranged to receive a measured charge of a volatile liquefied gas, means for withdrawing liquid from each of these vessels. , means for effecting the countercurrent passage of gas and liquid, associated with some of these receptacles such that gas at a relatively high pressure passes through liquid at a lower pressure, additional means for rapidly effecting the countercurrent passage of gas and liquid without gas passing through the liquid, means for effecting the cross-equalization of gas between parallel pairs of vessels at relatively different pressures, in a manner providing gas discharge through liquid. 35. In a cascade system for transferring liquid oxygen and the like, the combination with a supply vessel for liquid oxygen maintained at relatively low pressure, a heater for oxygen, maintained at a relatively high pressure, from a number of pressurized transfer vessels some of which successively discharge into each other, so that a number of different intermediate pressure levels can be maintained, a conduit for supplying a charge of liquefied gas from this supply vessel to a transfer vessel at the lowest intermediate pressure, means for controlling the passage of gas and liquid, associated with these receptacles and arranged so as to pass gas through the liquid and to condense at least part of the gas, so that the net loss is reduced, means of passing the oxygen increased from the phase liquid coming from the container <Desc / Clms Page number 53> at the highest intermediate pressure directly into the heater. 36. In a cascade system of the kind described, the combination with a number of transfer pressure vessels each arranged to receive loads of volatile liquid material, means for removing material from the liquid phase from each of these. receptacles, means combined with some of these receptacles to substantially exclude heat from these loads, thereby conserving the refrigeration, the condensing capacity or the available energy of these loads, means of carrying out, by the passage in relative counter-current of matter in the gas and liquid phases associated with these vessels in a heat exchange relation, a condensation of portions of gas into liquid, which reduces the blowing loss accompanying the initial charge in a relatively small amount, and means of applying forces of external origin to the matter to ultimately discharge the matter from the liquid phase. 37. In a cascade system for transferring volatile liquid material from a supply vessel, where it is maintained at a relatively low pressure, to a receiving device at a relatively high pressure, the combination of a number of transfer vessels intended to contain a succession of loads of material, in the liquid phase and materials in the phase. gas produced as a result of the heat gained in the transfer and for effecting the relative countercurrent passage of liquid and gaseous phases in a heat exchange relationship, means associated with some of these receptacles for maintaining refrigeration material in the liquid phase for use in condensing a desired part of material in the gas phase during this countercurrent passage, so that the final loss of material in the gas phase <Desc / Clms Page number 54> gas is reduced to a desired low value, and means for ultimately discharging the material from the liquid phase by the application of forces of external origin. 38. In a cascade system for transferring volatile liquid material from a supply vessel, where it is maintained at relatively low pressure, to a receiving device at relatively high pressure, the combination of a number of transfer vessels intended to contain a succession of loads of material at several pressure levels in both the liquid phase and the gas phase, this gas phase comprising gas produced as a result of the heat gained in the transfer, means of connecting these containers in cascade to effect a passage in relative countercurrent of liquid and gas phases in a heat exchange relationship, means associated with some of these containers for maintaining refrigeration of the material in the liquid phase for use in condensing a desired portion of material in the gas phase during this countercurrent passage, so that the final loss of material in the gas phase is reduced to a desired low value, means for supplying measured loads of volatile liquid material to the transfer vessel at the lowest pressure and means for supplying controllably heat to the material which is transferred after a desired portion of its refrigeration has been used to gas the material. 39. In a cascade system for transferring volatile liquid material from a supply vessel where it is contained at relatively low pressure to a receiving device at relatively high pressure, the combination of a number transfer vessels connected in series, the first discharging into the second to contain charges of that material and the gas produced by it <Desc / Clms Page number 55> as a result of the heat gained during the discharge, means associated with this series of receptacles for preserving the refrigeration of these charges of material in the liquid phase from destruction by supply of unwanted heat, means of equalize the pressures of a pair of vessels in series, by conducting gas from a higher pressure vessel into intimate contact with the liquid in the lower pressure vessel, so that a desired portion of gas is condensed by refrigeration of the liquid, thereby causing an exchange of gas and liquid between these receptacles. 40. In a cascade system for transferring volatile liquid material from a feed container, where it is contained at relatively low pressure, to a receiving device at relatively high pressure, the combination with means to provide measured charges of the material, from a number of transfer vessels connected in series to contain these charges along with the gas which may be produced from them as a result of the heat gained, upon the discharge of these receptacles, of means associated with certain of these receptacles to preserve the refrigeration of these loads of material in the liquid phase of the destruction by the arrival of unwanted heat, of means of equalizing the pressure of adjacent receptacles by conducting gas in intimate contact with the liquid, so that a desired portion of the gas is condensed by the refrigeration of the liquid, and means for causing an exchange of gas and liquid between adjacent containers. 41. In a cascade system for transferring liquid oxygen and the like, the combination with a reservoir for liquid oxygen maintained at a relatively low pressure, a heater for the oxygen liquid maintained at a relatively high pressure, from a number of pressure vessels some of which <Desc / Clms Page number 56> discharge successively into each other so that a number of different intermediate pressure stages can be maintained, from a conduit for supplying a liquid oxygen charge from that reservoir to a vessel at the lowest intermediate pressure, gas and liquid exchange passages connecting these receptacles which discharge into each other, additional gas exchange passages through which the gas pressure in a pair of communicating vessels can be equalized, and conduits for transferring the charge from a pressure vessel at the highest intermediate pressure to that heater . 42. In a cascade system for transferring liquid oxygen and the like, the combination with a reservoir for liquid oxygen maintained at a relatively low pressure, an oxygen heater liquid maintained at a relatively high pressure, from a number of pressure vessels some of which discharge successively into each other so that a number of different intermediate pressure stages can be maintained. a conduit for supplying a charge of liquid oxygen from this reservoir to a container at the lowest intermediate pressure, gas and liquid exchange passages connecting these containers which discharge into each other, additional passages gas exchange connecting these receptacles which discharge into each other, gas equalization passages connecting receptacles arranged to be maintained at the same pressure stages, and conduits enclosing a return connection connecting this heater directly to a receptacle which, in this series of discharge , is at the highest pressure in the series. 43. In a cascade system for transferring liquid oxygen and the like, the combination with <Desc / Clms Page number 57> a reservoir for liquid oxygen maintained at a relatively low pressure, a heater for liquid oxygen maintained at a relatively high pressure, a number of pressure vessels some of which successively discharge the one into the other so that a number of different intermediate pressure stages can be maintained, from a final pressure vessel arranged to receive the discharge from the series of pressure vessels successively charged, and maintained at the highest pressure stage maintained intermediately between the tank and the heating device, means of transferring a charge of liquid oxygen from this reservoir into a container at the lowest intermediate pressure, means of effecting the advancement of this charge in the series, accompanied by the displacement of gas and the partial oondensa- tion gas displaced into liquid, so that the load is increased, means of supplying heating fluid to heat this final pressure vessel when the temperature and pressure of the gaseous material in it reach critical values, and means for transferring the load in a homogeneous phase from this final pressure vessel to the heater. 44. In an apparatus for transferring liquid oxygen and the like, the combination with a portable liquid oxygen tank, a receiving vessel, a number of communicating transfer vessels arranged in a row. series and interposed between the reservoir and the receiving receptacle, of means for admitting a measured charge of liquid from the reservoir to the first of these receptacles while the communication with any subsequent receptacle is closed, means of equalizing the pressures of gaseous oxygen in these transfer vessels and means of discharging the liquid oxygen from each vessel of <Desc / Clms Page number 58> transfer to a subsequent vessel with a countercurrent passage of gaseous oxygen accompanied by an exchange of heat between the passing gas and liquid, this liquid discharge being established to carry away the heat of external origin from any transfer container chosen. 45. In an apparatus for transferring valuable volatile liquid the combination of a thermally insulated supply tank, a receiving vessel, a number of communicable transfer vessels arranged in series and interposed between the reservoir and the receiving receptacle, means of admitting a measured charge of liquid from the reservoir to the first of these transfer receptacles while the communication is closed from the latter to any subsequent receptacle, of means of discharge the liquid from this first container to a subsequent container under the influence of a gravity field accompanied by a displacement of gas, means of placing this first transfer container in communication with the outside, a means of '' equalize the gas pressures in the transfer vessels, and means for effecting the flow of liquid from the final container of the series to the receiving container while the communication is closed to the preceding container. 46. In an apparatus for transferring valuable volatile liquid, the combination with a thermally insulated supply vessel, a receiving vessel, a number of intermediate vessels comprising a group arranged in parallel and interposed between the supply receptacle and the receiving receptacle, means of choosing and placing in communication with the outside a receptacle of this group, of means of transferring a measured charge of liquid from this receptacle d 'power supply in this receptacle chosen when it has been put in communication with the outside and that the communication with other receptacles of the <Desc / Clms Page number 59> group is closed, of means of debiting this load towards the receiving reoipient, these means enclosing connections for selectively effecting the passage of gaseous material from other vessels of this group having a relatively high internal energy value in heat exchange relation with the transferred liquid charge, so that pressure equalizations between the environment of this load and the next receiving vessel are caused, and means for effecting the flow of this load to the next vessel where pressure equalizations have been sufficiently established. 47. In an apparatus for transferring valuable volatile liquid, the combination with a thermally insulated supply vessel, a receiving vessel, a number of intermediate vessels comprising a group arranged in parallel and interposed between the supply receiver and the receiver receptacle, means of choosing and communicating with the outside a receptacle of this group, means of transferring a measured charge of liquid from this supply receptacle into this container chosen when it has been placed in communication with the outside and the communication with other containers of the group is closed, means of delivering this load to the receiving container, these means containing connections for selectively and successively effecting a countercurrent passage of gaseous material from other containers of this group through the liquid feed, so that a flooding of gaseous material into liquid is effected and that pressure equalizations with those prevailing in these other containers take place in stages, and of means for effecting the flow rate of the load from this selected container to the receiving container while the communication is closed to the preceding container. <Desc / Clms Page number 60> 48. In an apparatus for transferring a gaseous material which has a boiling point significantly below 273 K, the combination with a thermally insulated feed container, a receiving container, a number of transfer vessels arranged to form a group of series which are in parallel and interposed between the supply vessel and the receiving vessel, means for admitting a measured load of liquid from the vessel d supply to the initial container of a series selected while communication with a next container in the series is closed, means for delivering this charge to a next container in the series, enclosing the connections for establishing gaseous communication between the container full and the next container, so that a first stage of pressure equalization is made, and further connections to establish gaseous communication between the filled container and a parallel container with the next container for cross-equalization of the pressure, so that a partial condensation of material from the gas phase to the liquid phase is effected to increase the transferred charge, and means to effect the flow of this increased charge from a final vessel of the selected series to the receiving vessel while that communication is closed to the previous recipient in @ the selected series.