US3869876A

US3869876A - Apparatus for tempering glass

Info

Publication number: US3869876A
Application number: US369212A
Authority: US
Inventors: Maurice Gardent; Wadislaw Michalak; Roger Prost
Original assignee: Air Liquide SA
Current assignee: Air Liquide SA; LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority date: 1972-06-15
Filing date: 1973-06-12
Publication date: 1975-03-11
Anticipated expiration: 1992-03-11
Also published as: DE7322367U; FR2187711A1

Abstract

Apparatus for tempering objects, in particular objects made of glass, comprising means for heating each said object substantially to its softening point; putting said object into direct contact, in a tempering chamber, with a projected flow of refrigerant fluid, such as liquid nitrogen, drawn from a main continuous nitrogen-storage tank; extracting from said main tank a definite measured quantity of said refrigerant fluid, sufficient for one single tempering operation on said object; transferring said measured quantity to an auxiliary temporary storage tank disposed close to said tempering chamber; and projecting said measured quantity of refrigerant fluid into said tempering chamber by applying to said auxiliary storage tank, for a very short time, a pressure which is substantially higher than that existing in said main storage tank. The invention is also directed to a gas-extraction clapper-valve for separating the gaseous and liquid phases of the refrigerant fluid.

Description

Unite l' States atet 91 Gardent et al.

[ APPARATUS FOR TEMPERING GLASS [75] Inventors: Maurice Gardent, Meylan;

Wadislaw Michalak, Sassenage; Roger Prost, Saint Egreve, all of France [73] Assignee: LAir Liquide, Societe Anonyme pour IEtude et IExploitation des Procedes Georges Claude, Paris, France [22] Filed: June 12, 1973 [21] Appl. No.: 369,212

[30] Foreign Application Priority Data June 15, 1972 France 72.21543 [52] US. Cl. 62/376, 65/349 [51] Int. Cl. F25d 17/02 [58] Field of Search 65/349, 348, 116; 65/62, 65/64, 373, 376

[56] References Cited UNITED STATES PATENTS 3.603.102 9/l97l Banas 62/64 Primary Examiner-Meyer Perlin Assistant Examiner-Ronald C. Capossela Attorney, Agent, or Firm-Young and Thompson [57] ABSTRACT Apparatus for tempering objects, in particular objects made of glass, comprising means for heating each said object substantially to its softening point; putting said object into direct contact, in a tempering chamber, with a projected flow of refrigerant fluid, such as liquid nitrogen, drawn from a main continuous nitrogenstorage tank; extracting from said main tank a definite measured quantity of said refrigerant fluid, sufficient for one single tempering operation on said object; transferring said measured quantity to an auxiliary temporary storage tank disposed close to said tempering chamber; and projecting said measured quantity of refrigerant fluid into said tempering chamber by applying to said auxiliary storage tank, for a very short time, a pressure which is substantially higher than that existing in said main storage tank.

The invention is also directed to a gasextraction clapper-valve for separating the gaseous and liquid phases of the refrigerant fluid.

12 Claims, 11 Drawing Figures PATENTED 1 I975 sum 5 m 5 FIG.8

FIGJO APPARATUS FOR TEMPERING GLASS The present invention relates to the tempering of articles, and especially of articles made of glass.

In the case of tempering of glass objects, it is known to heat these objects to the softening point of the glass and then to put the heated objects in direct contact with a refrigerant fluid projected in the form of jets, of liquid nitrogen for example, obtained by direct extraction from a main continuous storage tank put under pressure. As it vaporizes, the refrigerant fluid supplies the cold necessary for the rapid cooling of the object to be tempered, causing the superficial layers of the glass to be put under compression, while the centre of the article treated is under tension. In order to increase the exchange coefficient between the object to be cooled and the refrigerant fluid, this latter is generally projected in the form of fine particles, that is to say by spraying.

A method of this kind is generally utilized with a device or apparatus comprising a heat insulated tempering chamber provided with inlet and outlet means for the said article, a projecting system for the refrigerant fluid comprising a projection bench provided with a plurality of devices for spraying the said fluid, directed towards the interior of the tempering chamber, a fluidsupply means utilized for the projection bench from a main storage tank, together with a receptacle for recovering the residual refrigerant fluid and heat-insulated,

arranged in the lower part of the tempering chamber and associated with means for recycling to the projection bench.

A tempering process of this kind necessitates the use of continuous storage of the refrigerant fluid in the liquid form and under pressure (of at least two bars absolute).

In addition, the tempering process adopted does not enable an exact appreciation to be made of the quantity of refrigerant fluid strictly necessary to carry out the treatment of a given article. Nor does it enable an accurate control to be effected of the quantity of refrigerant fluid consumed during the course of the treatment. All these disadvantages generally involve excessive consumption of refrigerant fluid.

The essential object of the invention is therefore to provide a device for tempering which makes it possible at the same time to estimate accurately (in particular with an approximation of i 0.5 percent) of the quantity of refrigerant fluid required per article treated, and to control the quantity of fluid actually consumed during the course of the treatment.

The object of the invention is satisfied by a tempering apparatus in which:

1. From the main continuous storage tank of refrigerant fluid chosen, there is extracted a measured quantity of this latter, necessary and sufficient for a single tempering operation for a given article to be treated. The main storage tank is generally under a low pressure (atmospheric pressure for example);

2. the measured quantity of refrigerant fluid is transferred into an auxiliary and temporary storage tank arranged close to the tempering chamber and serving as a relay between the main tank and the projection zone of the fluis employed;

3. Rapid projection is effected of the measured quantity, temporarily stored in the auxiliary tank, which is put under pressure for a very short time with respect to the low pressure existing in the main tank. The pressure in the auxiliary storage tank is then reduced to the low pressure of the main storage tank. The projection. and where so applicable, the apraying of the refrigerant fluid employed'are thus carried out according to the invention by applying pressure impulses on the auxiliary storage tank which temporarily contains a measured quantity of the refrigerant fluid.

In order to carry the invention into effect, the projection system for the refrigerant fluid of the tempering device comprises:

1. At least one auxiliary storage tank, heat-insulated and intended to receive each measured quantity of the refrigerant fluid. The wall of this tank is intended to withstand an internal pressure considerably higher than the internal pressure of the main storage tank. This auxiliary storage tank communicates on the one hand with a refrigerant fluid supply means and on the other hand with the projection bench, through the intermediary of a siphon;

2. means for applying and removing pressure from the auxiliary storage tank.

The invention also relates to a de-aeration valve cooperating closely with the projection bench of the refrigerant fluid, and necessary for the operation of this latter, ensuring during the application of cold to this latter, the exclusive passage of the gaseous phaseof the said fluid towards the exterior, and the exclusive stopping of the liquid phase of the said fluid. This clappervalve comprises a closure device free and enclosed in a housing provided at its two extremities with two oriflees forming a seating for the said device, one upstream for the introduction of the said phases and the other downstream for the exclusive evacuation of the gaseous phase.

The closure device may occupy three positions, namely a stable closure position for the upstream orifice, a stable exclusive stopping position for the liquid phase in which it closes the downstream orifice, and an exclusive passage position for the gaseous phase in which it is in pneumatic suspension in the vicinity of the upstream orifice.

The tempering process defined above is more particularly applied to objects or articles of glass, but it may quite clearly be applied to the tempering of objects of steel or any other metal. The shape of the articles to be tempered has no effect on the execution of the invention, whether these articles are flat (window glass, mirrors, etc), concave or convex (spectacle glasses, for'example), or having any other geometrical shape.

The various characteristic features and advantages of the invention will furthermore be brought out in the description which follows below, by way of example, reference being made to the accompanying drawings, in which:

FIG. 1 is a diagrammatic view of a tempering device according to the invention;

FIG. 2 is a detailed view in cross-section of a tempering device;

FIG. 3 is a general view of the tempering device mounted on rails;

FIG. 3 represents a view in cross-section taken along the line AA' of FIG. 3 of a detail of a device according to the invention;

FIG. 4 is a front view of the perforated distribution side wall;

FIG. 5 is a view in cross-section of the said wall;

FIGS. 6 and 7 represent a spraying device suitable for mounting on the wall shown in FIGS. 4 and FIGS. 8, 9 and 10 show a de-aeration clapper-valve according to the invention, together with its method of operation.

Referring to FIG. 1, a tempering device according to the invention comprises a tempering chamber 12 heatinsulated with a material 740 provided with an inlet means and outlet means 701 for the article to be tempered, a projection system 702 for the refrigerant fluid utilized (a cryogenic liquid) directed towards the interior of the chamber 12, a supply means 705 of refrigerant fluid utilized on a projection bench 704, from a main storage tank 1, together with a receptacle 13 for the recovery of the residual refrigerant fluid, heatinsulated and arranged at the lower part of the tempering chamber 12, and associated with re-cycling means (pump 10) of the residual fluid towards the projection bench 704. t

The projection system 702 comprises two projection receptacles 2A and 2B of the refrigerant fluid, arranged facing each other on each side of the tempering chamber 12, and movably mounted with respect to this latter along the axis 711.

Each projection receptacle 2 having the geometrical shape of a palm, comprises a convex wall 710, a perforated wall 21 directed towards the tempering chamber 12, and a partition 709, substantially parallel to the perforated wall 21. The partition 709 forms on one side with the convex wall 710, an auxiliary storage tank 20 for a pre-determined and measured quantity of the refrigerant fluid, and on the other side with the perforated wall 21, a distribution chamber 708 for the refrigerant fluid. The auxiliary storage tank 20 and the distribution chamber 708 are heat-insulated.

Each auxiliary tank 20 communicates on the one hand with the supply means 705 of refrigerant fluid from the main and continuous storage tank 1, controlled by a valve EV 4, and on the other hand with the projection bench 704 through the intermediary of a siphon 7 arranged inside the said tank. This siphon 7 comprises a rising circulation conduit 7 and a downward circulation conduit 7", communicating with each other at one extremity, and more particularly at a high level, and at the other extremity with a low level of the auxiliary tank 20 and a low level of the projection bench 704 respectively, more precisely with a low level of the distribution chamber 708.

A projection system according to the invention further comprises pressurizing and de-pressurizing means for each auxiliary storage tank 20. The pressurizing means comprises a conduit 706 connected toa source 15 of gas under pressure through the intermediary of a control valve EV 2, communicating with a high level of each tank 20.

The tie-pressurizing means comprises a gasextraction valve Vl communicating with a high level of each auxiliary storage tank through the intermediary of the conduit 706, and a gas-introduction conduit 707 connected to the source 15 of gas under pressure through the intermediary ofa control valve EV 3, communicating with a high level of each siphon 7.

Each distribution chamber 708 communicates at a high level with a de-aeration valve 8 which will be described later.

The tempering chamber 12 is provided with an injection device 713, communicating with the recovery receptacle 13 through the intermediary of the re-cycling means 10 and the conduit 11.

The operation of the tempering device described above is as follows:

In the case of a glass article to be treated, such as a plate 703, there is extracted from the main storage tank 1 a definite and measured quantity of the refrigerant fluid, necessary and sufficient to carry out a single tempering operation of the object treated. This quantity of the refrigerant fluid is transferred and divided between the two auxiliary storage tanks 20a and 20b by means of the conduit 705 and the electro-valves EV4 and EVS.

The article to be tempered, previously heated up to its softening point, is then introduced into the tempering chamber 12 through the intermediary of the inlet and outlet means 701.

The tanks 20a and 20b being filled with a perfectly known quantity of refrigerant fluid (for example liquid nitrogen), are subjected for a very short time, in the vicinity of one second, to a pressurization which brings up the internal pressure of each of them to a value higher than the pressure existing in the main storage receptacle 1. This has the effect of driving the refrigerant fluid from the tanks 20a and 2012 through the siphon 7, and projecting the previously-measured quantity in the form ofjets directed against the surface of the article to be tempered.

At the beginning of this operation, the de-aeration valve 8 associated with each distribution chamber 708, permits a very rapid evaporation of the volume of gas remaining in the projection system, and enables the refrigerant fluid to be available in the liquid form from the first moments of the projection and spraying operation of the cryogenic liquid employed. The pressurization can be regulated and may have a value between 1 and 9 bars absolute by means of the electro-valve EV2 and to the large delivery pressure-reducing valve 6.

The electro-valve EV2 remains open during the whole of the tempering operation, and the pressure existing in the auxiliary storage tanks 20 is kept constant by means of the pressure-reducing device 6. During the tempering, the residual refrigerant fluid is collected in the liquid form in the recovery receptacle 13 after the passage of the liquid through the filter 14.

When the tempering has been completed, the treated article is extracted from the tempering chamber 12 through the outlet and inlet means 701, and the projection of refrigerant fluid is stopped by de-pressurizing the auxiliary storage tanks 20a and 20b. For that purpose, the valve EV2 is closed and simultaneously the valves EV3 and the valve Vl are opened. As the desired reduction in pressure is generally too slow (it takes about 1.5 seconds to pass from 9 bars absolute to 1 bar absolute), the circulation of the refrigerant fluid in the siphon 7 is practically immediately stopped by opening the valve EV 3 which enables gas under pressure to be introduced into this latter. This ensures the instantaneous unpriming of the siphon.

The residual refrigerant fluid subsisting at the end of this tempering operation, collected in the recovery chamber 13, can be re-cycled and re-employed for the next following tempering operation, by means of the pump 10 and the opening of the valves EV 9 and EV 10, which enables the refrigerant fluid recovered to be re-injected into the auxiliary storage tanks 20a and 20b.

This same re-cycling means permits a small flowrate of the recovered refrigerant fluid to be circulated towards an injection and spraying device 713 arranged inside the tempering chamber 12, by means of the conduit 11. By closing the valve EV 10 and opening the valve EV 9, it is thus possible to vaporize a certain quantity of the refrigerant fluid in the tempering chamber, and thus to keep this chamber cold between two successive operations.

A device for measuring the volume of the refrigerant or cryogenic liquid enables a continuous control to be effected of the quantity of liquid injected into the auxiliary storage tanks. This so-called bubbler device essentially comprises a differential pressure-gauge 3. In order to carry out the measurement of the injected volume, a gas, for example nitrogen, coming from the tank of gas under pressure is caused to circulate through the intermediary of a regulation valve 4, a flow-meter 5, one of the three electro-valves shown at EV 6, EV 7 and EV 8, the last of which EV 8 serves for control ling the liquid collected in the recovery chamber 13, separated from the tempering chamber 12 by a filter 14 for regenerating the quantities of cryogenic liquid recovered.

This measurement consists of eliminating the liquid which is present in

plunger tubes

16, 17 and 18, placed respectively in the tanks 20a, 20b and the chamber 13, and in proceeding to read the difference in height h on the pressure-gauge 3, caused by the pressure applied by the gas so as to expel the said liquid. This pressure is proportional to the height of the cryogenic liquid present in the tanks 20a and 20b and the chamber 13. There will now be described with reference to FIGS. 2 and 3, the details of the tempering device, the same reference numbers having been retained for the elements of the device which correspond to those of FIG. 1.

Two palms or projection receptacles 2A and 2B serve for tempering objects, of glass for example, by spraying liquid nitrogen. Only the palm 2A has been shown in FIG. 2 in view of the symmetry of the assembly. The elements of the palm 2B in FIG. 3 are provided with the index b.

The palm 2A comprises an elliptically domed external casing 20 with an upper opening having a cylindrical neck 11 forming a thermal sleeve for a tube 110 coaxial with the neck 111, opening into an auxiliary storage tank 140 of liquid nitrogen. This tank has a convex domed wall 107 of ellipitical contour, parallel to the external casing 20 and forming with this latter a heatinsulating chamber 152 under vacuum. Similarly, the opening 111 and the tube 110 form between them an annular heat-insulation chamber 151 in communication with the chamber 152.

The casing 20 is closed by a flat perforated wall 21, with perforations 200 intended to receive spraying devices or jets 202 directed towards the part to be tempered. The tank 140 has a flat wall or vertical partition 102 at a distance from the perforated wall 21, forming with this latter a distribution chamber for the cryogenic liquid to be sprayed, and extending substantially over the whole length of the major axis of the ellipse formed by the said tank 140.

This wall 102 forms at its lower portion a passage 142 with a vertical conduit 105 for downward circulation, through the intermediary of an elbow 142. The wall 102 is connected to the domed wall 107 while leaving the passage 142 which opens in a siphon formed by the cylindrical conduit and another cylindrical conduit 103 for downward circulation, coaxial with the cylinder 105 and having a larger diameter than this latter. The conduits 103 and 105 couple the wall 102 to its lower portion 103, and the conduit 105 is also coupled to the lower portion ofthe domed wall 107 by the elbow 142. The conduit 103 surrounding the conduit 105 plunges substantially into the chamber formed by the domed face 107 and the conduit 105.

The upper portion or high level 105a of the conduit 105 is open, whereas the upper portion or high level 103a of the conduit 103 is closed. The conduit 103 is longer than the conduit 105, which causes it to surround completely the conduit 105 at its upper portion. The two conduits 103 and 105 form between each other an annular chamber 141 with rising circulation. in communication with the tank 140.

The whole of the conduits 103 and 105 and the walls 102 and 107 defines a siphon 7 through the intermediary of the annular passage 142 which opens into the distribution chamber 700, comprised between the facing walls 21 and 102. The conduit 105 forms an internal siphon tube and the conduit 1 103 forms the external siphon tube. The interior of the tube 105 forms a downward circulation conduit 7' for the cryogenic liquid, and communicates with a low level of the distribution chamber 700 through the intermediary of the passage 142.

A tube 162 communicating with a valve of the type EV 3 is welded to the upper part of the conduit 103, passes parallel to and inside the tube 110, and passes through an elbowed tube which is also welded on the tube 110. The tube 162 is provided with a coupling 163 and the opening with the neck 111 is hermetically closed by a washer 119 which grips the tube 110. The tube 115 is connected to an electro-valve of the same type as EV 2 of FIG. 1.

Two

conduits

106 and 16, placed in the tube 110, open into two couplings 114 ad 1140, diametrically mounted on the elbowed tube 115. The conduit 106 serves to bring liquid nitrogen into the tank 140 and extends substantially down to the bottom of the said tank. The conduit 16 is placed in the tank 140, substantially at the same depth as the conduit 106, is provided with four orifices at 90 from each other (not shown), and serves for the measurement of the level by bubbling. The conduit 106 is connected to an electro-valve of the type EV 4, EV 5, while the conduit 16 is connected to an electro-valve of the same type as EV 6 and EV 7 of FIG. 1.

The mechanical coupling between the

walls

21 and 107 is effected by a collar 118. An abutment 104 enables the distance between the walls 21 and 102 to be maintained when the palm is pressurized. For heatinsulation reasons, the domed facing

walls

20 and 107 have been given a mirror polish. The vacuum existing in the interstitial chamber comprised between the

walls

107 and 20 is effected through an orifice 120.

A collar serves for the guiding and fluid-tightness of the domed wall 107 with the wall 21 which carries the jets 202.

The displacement of the palm 2A is effected by rolling on two frame-rails 123. A supporting rib 109 fixed to the palm 2A by welding has a fixing shaft 116 for controlling the distance between the palms.

On this shaft 116 is mounted a tie-rod 124 which can be locked on the said shaft by a nut 117, and which fixes the distance between the palms. On the rail 123, a roller 121 mounted on a supporting plate 122 which is in turn welded on the rib 109, permits the movement of the palm 2A along the said rail. The mechanical coupling between the rib 109 and the tube 1 is effected by a supporting lug 113.

Between the two palms 2A and 2B there is placed at the height of this latter a tempering receptacle or chamber 12 in which the actual tempering is effected.

The articles, for example of glass brought-up to its softening point, come in through a cover-door 218. The movement of these articles is vertical and is effected downwards for the introduction before tempering and upwards for extraction after tempering. This door 218, protected by a reinforcement 203, is provided with an electro-magnetic control device 217 for its opening and closing. The receptacle 12 has a cylindrical ring shape 225, with a diameter slightly greater than that of the palms. It is heat-insulated by a wall 220, of polyurethane for example.

This wall 220 is held gripped in two sealing

collars

502 and 502. At the lower portion of the receptacle 12 there is mounted, substantially vertically below the door 218, a recovery receptacle 13 of ellipsoidal shape for collecting the liquid nitrogen which is not vaporized during the tempering operation.

A filter 14, intended to prevent fragments of glass from falling into the bottom of the receptacle 13, is interposed between the lower part of the receptacle 12 and the upper part of the receptacle 13. This latter is heat-insulated under vacuum by means of an external casing 208 of ellipsoidal shape, parallel to the receptacle 13. Spacing members 203 maintain a distance between the receptacle 13 and a funnel 250 which has at its upper part a strap 233 for fixing the filter 14.

A tube 251 passes substantially to the bottom of the receptacle l3 and serves for the measurement of level by bubbling. At its lower portion, it is provided with four holes at 90 from each other (not shown), and is connected to the electro-valve EV 8 (FIG. 1).

A heat-insulation cone 221 filled with polyurethane foam. covers the upper portion of the receptacle l3, and is coupled to the lower part of the insulating wall 220.

A T-shaped drainage tube 214, placed at the lower part of the receptacle 13, opens to the exterior of the said receptacle and comprises a coupling 213 and a coupling 216 for fitting to a device with electro-valves EV 9 and EV 10 and to a pump 10, as shown in FIG. 1.

An outlet 226, placed above the filter 14, permits the escape of gas generated by the tempering operation.

A support 207 permits the maintenance of the receptacle-chamber assembly for tempering on the remainder of the apparatus by rollers 207 on a supporting rail 123, as indicated in FIG. 3.

The palms 2A and 2B shown in FIG. 3 are mounted outside the receptacle 12. The guiding of the palms 2A and 2B in the chamber 12 during tempering is facilitated by the presence at the lateral extremities 401 of the ring 225, ofa slight conicity of 30 over a short distanee, as shown in FIG. 2. The palms 2A and 2B are placed in the receptacle 12 during the tempering, and the forward movement of the palms 2A and 2B is ensured by two operating screws 600, synchronized with each other by means of a pinion and chain drive (not shown), and comprising a crank-handle 601.

These screws slide in a bearing 235 with a ring 236 mounted on a fixing lug 234, this latter being fixed on the receptacle 12. The screws 600 are mounted on drive fixing shafts for the spacing between the palms, respectively shown at 116a and 11612. Tie-rods 124a and 124b, respectively mounted on the shafts 116a and 1l6b are provided at their lower portion with rollers 125a and l25b intended to drive the palms 2A and 25 on frame rails 123 mounted on the rail supports 123. Supporting plates 122a and 12% welded on the palms 2A and 28 respectively carry wheels 1210 and 12lb which roll on the frame rails 123.

The whole of the device moves on the rails 123 through the wheels 1210 and 121b, and the distance separating the palms remains fixed during the course of this-operation. This is necessary for several series of tempering operations for objects having the same form, under the same conditions.

However, the coupling between each palm 2A and 28 by the operating screw 600 may be retractable. It is then possible to displace each of the palms freely and rapidly on the rails 123.

Thereceptacle 13 placed under the receptacle 12 may be displaced along a rail 123" (see FIG. 3) by the support 207 by means of the rollers 207. A support 420 welded on the receptacle 13 carries a motor 406 which drives a pump 10 for re-cycling the liquid nitrogen, this pump being mounted between two electrovalves EV 9 and EV 10. The electro-valve EV 9 is connected at its other extremity to the bottom of the receptacle 13, and a substantially vertical conduit 11 is placed between the pump 10 and the electro-valve EV 10. This conduit 11 opens into the chamber 12 through a spraying nozzle (not shown) which serves for the injection of the cryogenic liquid which maintains cold the interior of the chamber 12.

In FIG. 2 is shown a de-aeration valve 199 mounted in an orifice 201 and permitting the cryogenic liquid sent over the distribution wall 21 for cryogenic liquid, to expel the volume of gas comprised in the various circulation and distribution chambers.

This de-aeration valve, of the ball-clapper type, a detailed description of which will be given later, permits very rapid evacuation of the volume of gas considered and enables sprayed cryogenic liquid to be available from the first second of application of pressure to the palms.

The operation of the device according to FIGS. 2 and 3 is as follows:

The palms are moved forward by means of the rails into the interior of the receptacle 12 through the intermediary of the operating screw 600. Liquid nitrogen is then introduced into the auxiliary storage tanks of the palms, and the mass of liquid enclosed in the palms. serving to temper the articles brought in through the door 218 by opening the cover 203' is then put under pressure by means of gaseous nitrogen through the conduits 115a and 115b. The quantity of unused liquid nitrogen is recovered in the receptacle 13 and serves, be-

. fore the next following tempering operation, to mainciated with spraying devices or jets 202 having a variable density of layout from one zone to another of the perforated wall. In other words, the orifices which receive the nozzles or jets are judiciously arranged on the distribution wall so as to permit the use of nozzles with a square and/or flat jet, depending on the samples to be tempered.

The nozzles may be replaced by plugs at certain points, depending on the nature of the objects to be tempered. The nozzles which may be employed are for example of the type such as those shown in FIGS. 6 and 7. There is then obtained a flat jet which is suitable for tempering glass plates. These nozzle jets 202 have an elliptical orifice 800.

There will now be described a de-aeration valve such as that shown by the reference number 199 in FIG. 2. Referring to FIG. 8, this de-aeration valve comprises a cylindrical housing 300 surmounted by two frustoconical portions, the first 301 serving as a clapper seating for a closure device, for example a ball B enclosed in the housing 300 and capable of moving freely inside the said housing, the second having the reference 302 serving to create a depression neck 310 with the ball B when the fluid passes out in the gaseous form at 311 at the beginning of the putting into operation of the tempering device (see FIG. 9).

As shown in FIGS. 8, 9 and 10, the clapper-valve 199 is mounted vertically and the

truncated cones

302 and 301 are provided at each extremity of the housing with an orifice, one on the upstream side 304 for introducing the liquid or gaseous phases of the fluid, the other downstream 305 exclusively for the evacuation of the gaseous phase. The diameter of the ball B is greater than that of the

orifices

304 and 305.

The method of operation of the clapper-valve 199 will now be described. During the application of cold to the palms, that is to say when the cryogenic liquid is brought through the siphon and the distribution chamher, a certain quantity of gas must be eliminated. The conditions of flow are such that the ball B (closure device) is held in a position for the exclusive passage of the gaseous phase in the vicinity of the cone 302 by the depression created at the level of the neck 310 and existing between the ball B and the conical section 302 (see FIG. 9). The ball B is then in pneumatic suspension in the vicinity of the upstream orifice 304.

As soon as the gas has been evacuated, it is the cryogenic liquid which reaches the orifice 304 and which replaces the gas. The flow conditions are no longer the same and the liquid under pressure is not deflected by the ball, which becomes pushed upwards against the conical section 301 which forms a clapper seating 201. As long as the pressure applied on the liquid in the chamber 300 which contains the ball produces a force greater than the weight of this latter, the closure device is in an exclusive stable stopped position of the liquid phase, for which it closes the downstream orifice 305.

As soon as the palms 2A and 2B are de-pressurized, the valve is opened and the ball returns to a stable position of rest on the conical section 302 (see FIG. 8), in which the closure member closes the upstream orifice 304.

It would be possible to conceive a clapper-valve working in the horizontal position, the ball being returned to the starting position by a restoring spring or a magnetic field, and operating according to the same principle.

In addition, the ball may have a density higher than that of the liquid (Teflon for example, with respect to liquid nitrogen) provided that the pressure of the liquid compensates for the weight of the ball.

What is claimed is:

l. A device for tempering objects by the projection of a refrigerant liquid onto a said object when the latter is heated to its softening temperature, comprising means defining a heat-insulated tempering chamber that provides a passageway for said objects, a projection system for refrigerant liquid comprising a projection bench directed toward the interior of said chamber, means for supplying said liquid to said projection bench from a main storage tank, a heat-insulated recovery receptacle for the residual refrigerant liquid disposed at a lower part of said tempering chamber, means for recycling said residual liquid from said recovery receptacle to said projection bench, said means for supplying said liquid further comprising at least one auxiliary storage tank adjacent said projection bench, means for feeding said refrigerant liquid from said main storage tank to said auxiliary tank, a siphon between said auxiliary storage tank and said projection bench, and pressurizing and de-pressurizing means for said auxiliary storage tank whereby when said auxiliary storage tank is pressurized, said refrigerant liquid flows through said siphon from said auxiliary storage tank to said projection bench.

2. A device as claimed in claim 1, in which said siphon is disposed inside said auxiliary storage tank.

3. A device as claimed in claim 1, in which said siphon comprises an upward-circulation conduit and a downward-circulation conduit, communicating with each other at one extremity at a high level and at the other extremity at a low level of said auxiliary tank and a low level of said projection bench respectively.

4. A device as claimed in claim 1, in which said tempering chamber is provided with an injection device for said refrigerant fluid, said device communicating with the recovery receptacle through the intermediary of re cycling means.

5. A device as claimed in claim 1, in which said depressurizing means comprises a gas-extraction means adapted to communicate with said auxiliary storage tank, and a gas-introduction means communicating with said siphon.

6. A device as claimed in claim 1, in which said projection bench comprises a distribution chamber for said refrigerant fluid, said chamber communicating with the siphon and comprising a perforated wall directed towards said tempering chamber.

7. A device as claimed in claim 6, in which each said perforation of said perforated wall is associated with a device for spraying said refrigerant fluid, said device being fixed on said perforated wall.

8. A device as claimed in claim 6, in which the density of the distribution of said perforations is variable from one zone of said perforated wall to another zone.

9. A device as claimed in claim 6, and further comprising a de-aeration valve adapted to communicate with a high level of said distribution chamber.

10. A device as claimed in claim 6, in which said distribution chamber and said auxiliary storage tank are integrated with a projection receptacle of said refrigerant fluid, comprising a convex wall and a partition substantially parallel to said perforated wall, said partition de-limiting said auxiliary tank on one side with said convex wall and said chamber with said perforated wall 12. A device as claimed in claim 11, in which said on the other side.

11. A device as claimed in claim 10, and further comprising two projection receptacles disposed facing each other on each side of said tempering chamber.

two receptacles are mounted in a movable manner with respect to said tempering chamber.

Claims

1. A device for tempering objects by the projection of a refrigerant liquid onto a said object when the latter is heated to its softening temperature, comprising means defining a heat-insulated tempering chamber that provides a passageway for said objects, a projection system for refrigerant liquid comprising a projection bench directed toward the interior of said chamber, means for supplying said liquid to said projection bench from a main storage tank, a heat-insulated recovery receptacle for the residual refrigerant liquid disposed at a lower part of said tempering chamber, means for recycling said residual liquid from said recovery receptacle to said projection bench, said means for supplying said liquid further comprising at least one auxiliary storage tank adjacent said projection bench, means for feeding said refrigerant liquid from said main storage tank to said auxiliary tank, a siphon between said auxiliary storage tank and said projection bench, and pressurizing and de-pressurizing means for said auxiliary storage tank whereby when said auxiliary storage tank is pressurized, said refrigerant liquid flows through said siphon from said auxiliary storage tank to said projection bench.

1. A device for tempering objects by the projection of a refrigerant liquid onto a said object when the latter is heated to its softening temperature, comprising means defining a heatinsulated tempering chamber that provides a passageway for said objects, a projection system for refrigerant liquid comprising a projection bench directed toward the interior of said chamber, means for supplying said liquid to said projection bench from a main storage tank, a heat-insulated recovery receptacle for the residual refrigerant liquid disposed at a lower part of said tempering chamber, means for recycling said residual liquid from said recovery receptacle to said projection bench, said means for supplying said liquid further comprising at least one auxiliary storage tank adjacent said projection bench, means for feeding said refrigerant liquid from said main storage tank to said auxiliary tank, a siphon between said auxiliary storage tank and said projection bench, and pressurizing and de-pressurizing means for said auxiliary storage tank whereby when said auxiliary storage tank is pressurized, said refrigerant liquid flows through said siphon from said auxiliary storage tank to said projection bench.

4. A device as claimed in claim 1, in which said tempering chamber is provided with an injection device for said refrigerant fluid, said device communicating with the recovery receptacle through the intermediary of re-cycling means.

10. A device as claimed in claim 6, in which said distribution chamber and said auxiliary storage tank are integrated with a projection receptacle of said refrigerant fluid, comprising a convex wall and a partition substantially parallel to said perforated wall, said partition de-limiting said auxiliary tank on one side with said convex wall and said chamber with said perforated wall on the other side.