DE2130071A1 - Method and device for cooling a liquid - Google Patents

Description

dr. W. Schalk dipl.-ing. P. Wirth dipl.-ing. G. Dannenberg

DR.V.SCHMIED-KOWARZIK DR. P. WEINHOLD DR. D. GUDEL

6 FRANKFURT AM MAIN

OK. E (CHENMEIMEI STRAlSI 39

June 16, 1971
Gu / gm

Air Products and Chemicals, Inc.
1339 Chestnut Street Philadelphia, Pennsylvania, USA

Method and device for cooling a liquid.

The invention relates to a method and a device for cooling a liquid by introducing a liquefied one Gas into the liquid. The invention can be used with particular advantage for the procurement of chilled water that is used, for example, in a batch mix of concrete.

When making concrete, chilled water is usually mixed with warm cement, gravel and sand in a conventional one Mixer mixed. If the temperature of the concrete mix exceeds 25 to 30 ° C before stirring, so the strength of the mixed, set concrete may drop below an acceptable fourth. Especially during dor warm summer months, ki ^ s and sand can be warmed up in this way be that the temperature of the mixture exceeds the specified upper limit viunn the water is not cooled.

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One method of controlling the temperature of the mixture dispensed from the mixer is to add at least some of the water in the form of crushed ice. However, this solution is unsatisfactory because the ice is made
got to.

placed and kept at a temperature below 0 °

. The present invention is directed to a method by which these problems are overcome by using a Liquefied gas is introduced into the water supply of the aqueous component, so that this is on a predetermined Temperature or cooled to a temperature within given limits, the temperature being above the freezing point of water.

With this type of cooling, the control of the cooling medium is provided poses a problem in local areas. Specifically, the water in the vicinity of the liquefied gas injector tends tends to freeze at the dispensing point, thereby clogging the injector so that no further liquefied gas is dispensed can be. Another difficulty is seeing the injector tube clear and unclogged during those Keep times when liquefied gas

is not introduced, ie during the time in which the water has reached the prescribed temperature. With subsequent W whose words the water in the injector in these times in which no liquefied gas is introduced to fight back into the injector, freeze there and clog the injector.

These problems are solved by the present invention, which is provided by a method for cooling water assumes a temperature below the ambient temperature and above the freezing point of water. The procedure is characterized in that an amount of liquid nitrogen is introduced into the water by evaporation Sufficient for the desired cooling, and that prevents clogging of the inlet channel by ice

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the
is that ^ in the vicinity of the inlet channel-located water is prevented from freezing.

The invention also provides a system for cooling water by direct injection of liquid nitrogen suggested in the water. The system comprises a horizontally aligned water reservoir in which a multitude of extends from injection nozzles for liquid nitrogen. Each of the nozzles has near its downstream The result is a heating element whose heat prevents the nozzle from icing up.

Finally, the invention proposes a method for producing concrete, which is characterized in that is that the water has reached a predetermined temperature Introducing a sufficient amount of liquid nitrogen into the water being cooled to allow cooling by evaporation of nitrogen in the water is achieved; that the inlet channel is thereby protected from clogging by ice that the water in the vicinity of the discharge channel is prevented from freezing; and that cement, gravel and sand is mixed with the cooled water, whereby the concrete thus formed is brought to a desired temperature will. Either all or part of the water required for the concrete is cooled.

The invention is explained in more detail below using an exemplary embodiment from which further important ones Features of the invention reveal. It shows:

schematically a diagram of a preferred embodiment of the invention; Figure 3 is a side view of a preferred nozzle assembly for use in the invention. The nozzle arrangement is screwed into a tank wall; a partial view of a modified embodiment of the heating element according to FIG. 2 \ a section along the line 3-3 of FIG. 2; 5 views of other nozzle arrangements that also

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Fig. 1 Fig. 2 Fig. 2A Fig.
Fig. 3
k and

can be used with advantage and FIG. 6 is a plan view of the arrangement of FIG.

In Fig. 1 is a system and method for cooling water by introducing liquid nitrogen into the water explained, with heat being the neighborhood of the injection.07.onc is supplied to keep this zone free from clogging with ice. The system includes a cylindrical one Tank 10 with a side wall 12 and end walls 14. The End walls 14 have slightly convex outer surfaces * The longitudinal axis of the cylindrical tank 10 is horizontal aligned.

A water supply line 16 is connected to the tank 10. The upstream end of the line 16 is in communication with a water supply, for example a source. The line 16 opens into the lower part of the tank 12 in one of its end walls 14 '. Furthermore, an outlet line 18 for water is connected to the tank 10'. The downstream end of the line 18 is at the place where the cold water is needed. The line 18 opens into the tank 10 at the lower end of the end wall 14, which is opposite the first end wall 14 into which the line 16 opens. The line 18 has a pump 20 by means of which the cooled water is drawn off from the tank 10 and pumped to its point of use. The line 16 has a pump 22 which is driven by a motor 24 which operates in response to a signal generated by a water level controller 26 and received from the motor 24 via electrical lines 28. The controller 26 operates depending on signals at display points J>'J or. 32 via lines 34 and 36. Point 32 is the lower display point and point 30 is the upper display point. If, as a result of the water withdrawn via line 18, the level in tank 10 and via point 32, C ¹ Jo control 26 actuates motor 24 via line 28 and starts pump 22 so that V / as κ or is fed to the tank 10 via the line 16. When the water level reaches the point. . ., r-.sp ^ 109853/1237

30, the controller 26 switches off the motor 24 via the line 28, whereby the pump 22 is also switched off will. So there is no longer any more water pumped into the tank 10 via the line 16.

The tank 10 has a plurality of injection nozzles or lances 38 for introducing liquid nitrogen into the Tank 10. Each of the nozzles is oriented vertically. All nozzles are in the side wall 12 along one line mounted, which is determined by the intersection of the side wall 12 with a vertical plane passing through the longitudinal axis of the tank goes. The nozzles 38 are arranged more or less uniformly along this line, so that a distribution of liquid nitrogen in the water is achieved. Each of the nozzles has an outlet at the downstream end. Each of the nozzles has a heating element 40 at its lower part. The heating elements 40 are via lines 42, 44 and a main line 46 is connected to a timer 48 which controls the heating elements 40 according to a predetermined time schedule activated. The upper part of the nozzles 38 is covered with an insulation 41. The heating elements and their function Elements and the nozzles waröai explained in more detail below,

With the upstream end of each nozzle 38 are Supply lines 50 for liquid nitrogen connected by each of which has a valve 52. The upstream end of each of the conduits 50 is connected to a main conduit 54 in connection, which in turn is connected via lines 56 and 58 to a reservoir 60 for liquid nitrogen are. The reservoir can simply be a pressurized tank. Liquid nitrogen, for example, can be about Tanker trucks placed in reservoir 60 v / ground. The administration 58 is equipped with valves 62 and 64.

A line 66 is also connected to the reservoir 60, which leads to an evaporator 68, which can simply be an expansion chamber or a heat exchanger. Dor Evaporator 68 has an outlet line 70 with a valve

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72 land stands with its downstream end with a line 74 in connection, which in turn opens into the line 56. The line 74 has a valve 76 .. With A line 78 containing a valve 80 is connected to the upstream end of the line 74. the Line 78 is connected at its upstream end to a source of compressed air. ·

The valve 76 is via a line 82 with a temperature control device 84 connected. A valve 64 is connected to the temperature control 84 via a line 86. the Temperature control 84 is also connected to a temperature sensor 92 via lines 88 and 90. This feeler 92 is, for example, a thermal cross or a thermocouple and is preferably located in the vicinity of the water outlet of the tank 10.

The tank 10 has vent lines 94 for gaseous Nitrogenj those in the side wall in the upper part of the Tanks are provided.

The water in the tank 10 is brought to a predetermined temperature level, for example 0.5 to 5 ° C, by introducing liquid Nitrogen through the nozzles 38 into the tank 10 below the V / a s s level, cooled.

The introduction of the nitrogen is controlled by the regulating or control device 84, which in turn is controlled by signals is activated, which is generated by the sensor 92 v / earth. When the temperature of the water in the tank 10 is measured by the sensor 92 and is above the desired, predetermined value, a signal is over the lines 88 and 90 to the control device 84, which acts via the connection 86 and opens the valve 64. During operation will be the valves 62 and 52 are held in the open position. As a result of the opening of the valve 64, the liquid nitrogen flows under pressure in the reservoir 60 via lines 58, 56, 54 and 50 in and through the nozzles 38 and into the water in the

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Tank 10 to cool this water. When the temperature deti V / aterG in the tank 10 reaches the predetermined, desired level, as is measured at the measuring location of the sensor 92, a signal i or the lines 88 and 90 is fed to the control device 8h , which then closes the valve 64. In operation, valve 72 is normally held open and valve 80 is normally closed. Liquid nitrogen from the reservoir 60, which was introduced into the evaporator 68 via the line 66, is evaporated there and supplies dry nitrogen gas.

The temperature controller 84 opens the valve 76 at the same time as the valve 64 ₁ closes. As a result of the opening of valve 76, nitrogen gas flows from evaporator 68 via lines 70, 74, 56, 54 and 50 into and through nozzles 38 and flows out of the downstream openings in nozzles 38 below the water level in tank 10. Da Nitrogen gas is passed through the nozzles 38 during the times when liquid nitrogen is not passed through these nozzles, water in the tank 10 cannot flow back into the nozzles 38, so that the water freezes in the "nozzles 38 and thus a Clogging of the nozzles is prevented.

When the temperature measured by the sensor 92 exceeds the desired confusion, a signal from the sensor 92 activates the control device 84 and closes the valve 76, whereby the valve 64 is opened. So it becomes more fluid Nitrogen is again introduced into the water in tank 10 and the supply of gaseous nitrogen ceases.

Compressed air is available that can be used in place of the vaporized nitrogen in the event of the nitrogen supply is low or the nitrogen evaporator is not working properly. In other words, the compressed air creates you Substitute for vaporized nitrogen. If vaporized nitrogen is not used, valve 72 is closed gdialten and the valve 80 remains open so that pressurized air is introduced through the nozzles 38 during the times

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when liquid nitrogen is not forced through the nozzles 38. · The compressed air used is preferred dry.

The cooling of the water is achieved by the evaporation of the liquid nitrogen in the water of the tank 10, whereby A quantity of heat is withdrawn from the water, which escapes in the v / it corresponds to the heat of vaporization of the liquid nitrogen plus the amount of heat that is required to generate the Adjust the temperature of the generated nitrogen vapor to that of the water. The gaseous nitrogen from evaporation the liquid nitrogen that has been introduced into the tank is discharged from the tank 10 via vent lines 94. This also applies to nitrogen vapor or compressed air which were introduced through the nozzles 38 during the times when no liquid nitrogen is being supplied. The gas vented via the lines 94 is approximately at the temperature of the water in the tank 10 and is with Saturated water.

As mentioned, the water level is kept within specified limits during the operation described.

During operation of this system, the heating elements 40 are used on a predetermined timing schedule, as previously described, to add heat to the vicinity of the nozzle outlets so that ice formation at the end of the injectors is prevented. So no ice can bridge or clog the side walls of the injector lines around the injector's en.de. The heating element 40 thus supplies heat both to the ends of the nozzles and along the side walls of the nozzles in the vicinity of the nozzle ends. As mentioned above, the heat is emitted according to a predetermined time schedule. In other words, the heating elements 40 are operated in accordance with a signal from a timer 48 so that the Uär ^ e in vnl -.-: ^ brochoncu pearl ic η is supplied. For example, the timer 48 activates switches so that electrical voltages,?.; the I-heating elements h0,

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for example every minute for 30 seconds. At the end of this time, the timer 48 activates the switches, which then close so that electric current is not supplied to the heating elements 40. The electric one Current is fed to the heating elements 40 via lines described in more detail below. The heating elements 40 work as resistance heaters.

FIGS. 2 and 3 show a preferred embodiment of the injector nozzle together with the heating element. In FIGS. 2 and 3, the nozzle 38 is shown mounted in the side wall 12 of the cylindrical tank 10. The nozzle ¹ 38 is fastened there by means of a mounting plate 96 which is welded to the nozzle 38 or connected in some other suitable manner. The honing plate 96 is screwed into the side wall 12 by screws 98. A watertight connection is made between the side wall 12 and the plate 96 by using a shim 100. The nozzle 38 has insulating material 41 at its upper end. A hose clamp 102, which is placed around the insulating material 41, prevents water from rising between the insulating material and the nozzle and freezing there. In the vicinity of its downstream end, the nozzle 38 has a heating element 40, which will be explained in more detail below. The heating element 40 is connected at connection points 104 to lines 42 which are laid in a spiral around the insulation 41 and possibly through the plate 96 are guided in a watertight manner and are connected to a voltage source 106. The lines 42 are laid in a spiral around the outside of the insulation 41, so that the lines can give way when the length of the pipe changes. If this expansion space is not present due to the spiral routing of the lines, for example if the lines are routed directly along the insulation 41 parallel to the longitudinal axis, the lines can tear or break.

Read into the FIg. 2 and 3 shown heating element is ^{preferred for (} use in the invention. It consists essentially

1098-53 / 1237

They consist of a resistance conductor that is dimensioned so that heat is generated when the current flows through it. This is essentially a lead wire, the ends of which are connected to the connection points 104. Between these connection points, the heating element 40 is essentially U-shaped, with the two legs of the U extending essentially parallel to the longitudinal axis of the nozzle 38 and in the vicinity of the outer surface of the nozzle. The edges of the side wall of the nozzle. 38, which form the outer end of the nozzle 38 and at the same time the lowest point of the U, are in the same horizontal plane. The vertical portion of the U which is furthest from the connection points 104 extends approximately from the end of the nozzle to a point _{f in '} approximately opposite the connection points 104. Starting at this point, the heating element 40 is in a Transverse direction to the longitudinal axis of the nozzle 38, but always in "the vicinity of the nozzle 38, whereupon it is _{guided back s} and still adjacent to the nozzle 38, but this time in a direction parallel to the longitudinal axis of the nozzle 38 until it is once again reaching the downstream end of the nozzle 38, forming a second U-shaped configuration. This time the base is approximately opposite the connection points en 1Θ4. The heating element then extends transversely adjacent the edge of the "*" sidewall at the downstream end of the nozzle 38, whereupon it runs back twice, still adjacent to the nozzle 38 but in a direction parallel to the longitudinal axis of the nozzle 38, whereupon there is a connection point 104 e r reaching. This doubling results in a U-shaped configuration as part of the path of the heating element. The transverse dimension of each U is roughly equal to that. Length and opposite an inner radius of the nozzle 38. Just before it reaches the connection points 104, the heating element extends outwardly from the surface of the nozzle 38 so that the connection points 104 are not adjacent to the nozzle 38. The heating element shown in FIGS. 2 and 3 thus follows a path which consists essentially of three U-shaped configurations in succession, the first and third U being in the

109853/1237 bad original

extend substantially parallel and the second U by connecting the inner vertical legs of the first and third U is formed. Each of the vertical legs extends in a direction parallel to the longitudinal axis of the nozzle, the lower end of the base of the first and third U being substantially in a plane parallel to the end the nozzle is provided. The path is next to the outside surface of the nozzle, except where the path is merges into transition points 104 where the path turns slightly outward. A heating element of this The configuration and arrangement is appropriate to the formation of ice at the end of the nozzle 38 and along the side surfaces of the nozzle 38, which would otherwise result in bridging of the side surfaces around the nozzle end 38 could.

A suitable variation of the heating element according to FIG. 2 is shown in Figure 2A. The U-shaped parts of the heating element extend there in the vicinity of the nozzle end 38 with their upper side of the base essentially in one plane containing the nozzle end 38, in contrast to FIG. 2, where the lower surface of the U-shaped parts essentially lie in the plane.

Nozzles with other suitable heating elements sir © i in the Figs. 4 and 5 are shown. 4 shows a nozzle 38 which is provided on a mounting plate 96. Of the upstream part of the nozzle also has an insulation 41 with a watertight seal between the nozzle 38 and the insulation 41 by clips 102. Lines 42 are spirally wound around the insulation 41 and extend through the honing plate 96 to a voltage source 106. The lines 42 are connected to the heating element 40 via connection points 104 connected. In the embodiment of FIG. 4, the heating element 40 extends spirally around the Nozzle 3S until it reaches a point near the nozzle end, whereupon it doubles in a spiral around the Nozzle 38 is wound back, so that the two,

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Spiral parts extend essentially parallel to one another. A top view of B'ig. 4 is shown in Fig. 6; from it it can be seen that the mounting plate 96 has four openings 108 through which screws that secure the plate screw to the tank wall.

Fig. 5 shows a nozzle 38 with an insulation 41, the ebcn » • if held by sealing clamps 102. Even there a heating element 40 is provided, which at connection points 104 is connected to lines 42. The heating element extends in a path along the outer surface of the lower Part of the nozzle 38 spirals around this area, with 'one of the connection points 104 facing downstream End of the nozzle 38 is arranged.

It should be particularly pointed out that the vertical arrangement of the nozzles with respect to the tank 10 is important in these embodiments. If the nozzles are arranged horizontally, the turbulence caused by the outflowing liquid nitrogen can cause the water reservoir to be unstable.

The following example additionally illustrates a preferred one Method und.a device for cooling water.

w ' Example.

For this purpose, the constant and the method, as in Fig. 1 explained, used. The heating element of each nozzle has a configuration according to Fig. 2A.

The tank 10 shown in Fig. 1 is approximately 15 meters long and 3 meters in diameter. It holds 70,000 1. Each de-i · nozzle extends radially into the tank at a distance of 2.2 m. Ten nozzles are used «Each there is ten dunes. made of brass tubes with a clearance of 3/4 inch (ce .. 19 mm). Each heating element is connected to the outer surface of the nozzle in question by means of silver solder. Each lu / r-.z-

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element extends in a direction parallel to the longitudinal axis of the nozzle at a distance of 20 cm. the Leads to each heating element are spirally wound around the insulation 41 three times. Have vent lines 94 each has an inside diameter of 18 inches (about 45.7 mm). The lines 42 consist of M-1 cables.

The water enters the tank 10 at a temperature of 18 ° C. The method and the "device according to the Invention is used to cool the water to about 1.6 ° C. The chilled water is used to prepare

Concrete ends. The concrete is prepared in batches of 2.3 m. About 1000 liters of water are used to prepare 2.3 m "batch of concrete. The water with a temperature of 1.6 ° C is enough to cool the mixture to a temperature below 26.5 C, even if sand and gravel are one Have a temperature of 33.3 ° C.

The system is operated continuously. For each

3
2.3 m, 17 kg of liquid nitrogen are introduced through each of the ten nozzles into the water in the tank. The heating elements are heated for fifty percent of the time, with heating periods of 30 seconds alternating with unheated periods of also 30 seconds. Each heating element is in operation for half an hour and consumes one kilowatt hour of electrical energy during that time.

As a result · the water becomes liquid through the introduction Nitrogen cooled to a temperature of 1.6 ° C without freezing the water in or on the nozzle. Because the lines are wound in a spiral around the insulation, they cannot break or tear.

If a cooling of the water to a temperature of 0.6 ° C is desired and if sufficient liquid nitrogen is required is initiated to reach this temperature, 1.0 kilowatt hours of electrical energy from the Heating element of each nozzle during each period of one

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Half an hour is required to keep the nozzle frost-free.

Greater cooling can be achieved when the spent nitrogen withdrawn from vent line 94 is used for this around the gravel by introducing it Used nitrogen to cool in the gravel container. The nitrogen can then be discharged.

The invention can also be embodied in other embodiments Find use. For example, the nozzles can be designed to be adjustable. Additional cooling can also be used by adding frozen Vfesser or by spraying t can be achieved by liquid nitrogen on the gravel and / or sand. There can be other configurations for the Heating elements are selected. It is important that the end of the nozzle is protected from icing. Furthermore, a other inert gas other than nitrogen or air can be used to prevent the nozzles 38 from freezing during the To protect time in which no liquid nitrogen is supplied «For example, dry helium or argon perishes / ends up.

Patent or protection claims

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Claims (1)

June 16, 1971 Air Products and Chemicals, Inc. Gu / gm Philadelphia, Pennsylvania, USA Patent or protection claims Process for cooling water to a temperature below ambient temperature and above freezing point, characterized in that a quantity of liquid nitrogen is introduced into the water, which by evaporation is sufficient for the desired cooling, and that clogging of the inlet duct by ice thereby preventing the water in the vicinity of the inlet channel from being on Freezing is prevented. 2. The method according to claim 1, characterized in that that the heat in the vicinity of the discharge channel is fed. 3. The method according to claim 2, characterized in that the heat is supplied according to a predetermined Zeitscheina will. 4. The method according to claim 2 or 3, characterized in that that the heat is supplied by an electrical resistance heater. 5. The method according to claim 1, characterized in that the liquid nitrogen is introduced intermittently depending on the cooling requirement and that an inert gas is introduced through the same introduction channel when liquid nitrogen is not introduced. 6. The method according to any one of claims 1 to 5, characterized in that the inlet channel of blockages both through the application of heat in the ■■■ ■ * 109853/1237 exercise of the inlet channel, as well as by introducing an inert gas along the inlet channel is kept free during those times when liquid nitrogen is not along the inlet channel is initiated. 7. Verfaliren according to claim 5 or 6, 'characterized in that that the secondary gas is nitrogen. 8. Device for cooling water by direct introduction of liquid nitrogen in the water, characterized in that a horizontally aligned water reservoir (10) - is provided, in which a plurality of injection nozzles (38) for liquid nitrogen extend, with each of the nozzles in the kälie of their has a heating element (AO) at the downstream end. 9 · Device according to claim 8, characterized in that a timer (48) is provided which the Heating elements (40) actuated according to a predetermined time switch scheme. In that a temperature sensor (92) is 10. Apparatus according to claim 8 or 9, gekennzeich- characterized * _t net provided which senses the water temperature in the reservoir (10) and capable of emitting a first signal when the water temperature is below a predetermined value befindiOfc , and which can emit a second signal when the water temperature is at the predetermined value, and that a control device (84) is provided for the temperature, the inflow of liquid nitrogen through the nozzles (38) in the reservoir (10) Initiates and maintains receipt of the first signal, and. the Zustroiu on the flüsr.ißoia nitrogen containing ".ilmpfang interrupts the second .Signals. 109853/1237 BADORfG ₁ NAL 11. The device according to claim 10, characterized in that that a source of a pressurized, inert gas is provided that the temperature control such is designed that inert gas flows from the source through the nozzle (38) when the flow of liquid Nitrogen ceases and that the flow of inert gas is interrupted when liquid nitrogen flows in . 12. Device according to one of claims 8 to 11, characterized in that the nozzles (38) aligned vertically are. 13. Nozzle arrangement for use in the device according to claim 10, 11 or 12, characterized by a Nozzle (38) which is open only at its downstream end and which is near the downstream directed end has an electrical heating element (40). 14. Nozzle arrangement according to claim 13), characterized in that that the heating element (40) is connected at connection points (104) with lines (42) which are led to an electrical voltage source (106). 15. Nozzle arrangement according to claim 14, characterized in that that the path of the heating element (40) consists essentially of three U-i 'shaped configurations in succession, the first and third configurations essentially being are parallel and the second configuration by the connection of the inner vertical legs of the first and third configuration is formed so that each of the vertical legs extends in a parallel direction extends to the axis of the nozzle (38) and that the Path extends near the outer surface of the nozzle except in the vicinity of the connection points (104), 109853/1237 where the 'path points away from the nozzle and to the connection scoring goes. 16. Nozzle arrangement according to claim 15? characterized, that the first and third configuration are formed such that the surfaces of their Bases in the same horizontal plane as the downstream. ': End of the nozzle lie. 17 · Nozzle arrangement according to claim 13 or 14, characterized characterized in that the heating element (40) extends helically around the tube. 18. Nozzle arrangement according to claim 13 or 14, characterized in that the part of the nozzle (38) which is not is in contact with the heating element (40), is covered by an insulation (41) around which the lines (42) are placed in a spiral. 19. Process for the production of concrete using the Method according to one of Claims 1 to 7> characterized in that the water is heated to a predetermined temperature is cooled by the method according to any one of claims 1 to 7 that cement, gravel and sand with the cooled water is mixed, whereby the concrete thus formed is cooled to a desired temperature and that the amount of chilled water used is at least part of the total for which Manufacture of the buton corresponds to the amount of water used. The patent attorney: 109853/1237 bad original ft.