Machines for controlling the temperature of parts of industrial plants adapted to the formation of products

Abstract

The invention relates to a machine (10) for temperature control of a product-forming part of an industrial plant adapted for forming a product. The machine comprises at least one thermostatic hydraulic circuit (11) adapted to be operatively connected to a product-forming part of an industrial plant adapted for forming a product, a thermostatic liquid circulating through the hydraulic circuit (11). The hydraulic circuit comprises a pump (12) of variable flow rate type for recirculation of the thermostatic liquid, a delivery section (13) downstream of the pump (12) for delivery of the thermostatic liquid from the hydraulic circuit (11) to a product-forming part (B) of the industrial plant, a return section (14) for return of the thermostatic liquid from the product-forming part (B) of the industrial plant to the hydraulic circuit (11), and a heat exchange unit (15) for the thermostatic liquid arranged between the return section (14) and the pump (12), in which the thermostatic liquid is thermostatically regulated. The machine (10) further comprises an electronic control and management device (30). The electronic control and management device is configured with at least one value for an operating temperature of the temperature regulating liquid and at least one predetermined time-based pump flow rate change profile, and when a synchronization signal is received at a predetermined instant of the industrial process of product formation in a product formation section (B) of the industrial plant to be temperature regulated in accordance with the pump flow rate change profile, the pump (12) moves the temperature regulating liquid over time at a variable flow rate based on the pump flow rate change profile.

Description

[Technical field]

[0001] The invention relates to the field of industrial heat conditioning equipment, e.g. for moulding plants (die casting plants for plastic materials, metals, ceramics etc., endothermic and exothermic chemical reactors, glass processing plants etc.), and more particularly to machines for temperature control by industrial users, e.g. for moulding moulds. [Background technology]

[0002] As is well known, in many industrial processes, including moulding processes, for example in die casting plants for plastic materials, metals, ceramics etc., or in plants containing endothermic or exothermic reactors, or in glass processing plants etc., it is necessary to regulate the temperature in certain parts, especially in the parts of the system where the product formation takes place.

[0003] With particular reference to the use of moulding moulds to shape moulded articles, the temperature of the mould body must be regulated in order to optimise working times and final product quality.

[0004] For example, in plastic injection molding, molten plastic material is injected into a closed mold. The high temperature of the molten material heats up the mold. The process requires a certain waiting time after injection to allow the molded part contained in the mold to cool. To reduce this waiting time and ensure a proper temperature profile, the mold is cooled during molding.

[0005] Traditional cooling methods involve passing cooling water through ducts across the mold, the flow rate and temperature of which are kept constant throughout the process and are selected based on the desired mold cooling profile.

[0006] This cooling method is very simple and suitable for many types of situations.

[0007] On the other hand, the method of adjusting the temperature of the mold does not provide the best performance results in terms of the overall amount of energy used in the cooling process and the overall speed of the process. Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to solve the problems associated with the adjustment of parts of an industrial plant, such as moulds, during the process of forming a product by moulding.

[0009] It is therefore an object of the present invention to provide a machine for temperature control of a part of a plant for an industrial process, such as, for example, a forming mould, which makes it possible to reduce the amount of energy used when regulating the temperature in the part of the plant that is subject to thermal regulation.

[0010] Another important object of the invention is to provide a machine for temperature control of parts of a plant for industrial processes, such as moulding tools, which makes it possible to speed up the product formation process.

[0011] Another important object of the present invention is to provide a machine for temperature control of forming dies, which makes it possible to optimize the temperature profile of a part of a product forming plant in order to improve the quality of the product. [Means for solving the problem]

[0012] The above mentioned objects and other objects which will become more clear hereinafter are achieved by a machine for temperature control of a product forming part, preferably but not limited to a mould of an industrial plant, comprising at least one thermostatic hydraulic circuit adapted to be operatively connected to the product forming part of the industrial plant, a thermostatic fluid circulating in the hydraulic circuit. a recirculation pump for the temperature control liquid, of the variable flow type; a delivery section downstream of the pump for delivering the temperature-regulating fluid from the hydraulic circuit to a product-forming section of an industrial plant; a return section for returning the temperature-regulating fluid from the product forming section of the industrial plant to the hydraulic circuit; a heat exchange unit for a temperature regulating fluid, arranged between the return part and the pump, in which the temperature of the temperature regulating fluid is regulated; The machine further comprises an electronic control and management device configured with at least one value for an operating temperature of the temperature conditioned liquid and at least one predetermined time-based pump flow rate change profile, in accordance with which the pump moves the temperature conditioned liquid over time at a variable flow rate based on the predetermined flow rate change profile upon receiving a synchronization signal at a predetermined instant of an industrial process of product formation in the portion of the plant to be temperature conditioned.

[0013] Preferably, it is adapted to be connected to a product forming mould, whereby the part of the plant to be temperature regulated is the mould. In the following, explicit reference is made to the mould and to the moulding process using that mould. It should be noted that the embodiments of the machine described below, although they relate to moulds, are also applicable in cases where the machine can be connected to the delivery or return of product forming parts of industrial plants other than moulding plants, such as products made in chemical reactors or other devices.

[0014] Thus, the reception of a synchronization signal at a given moment of the industrial process of the product formation in the part of the plant to be thermoregulated relates to the movement of the thermoregulated liquid by a pump with a variable flow rate according to a given time-based flow rate change profile, and the synchronization signal can be any signal that correlates to a phase (or moment) in the production cycle of the industrial process of the product formation. This phase or moment must be constantly repeated at the same moment of the production cycle. For example, in the case of a forming process in a mould, the production cycle includes moments that are constantly repeated, such as the closing of the mould, the start of the injection of material into the mould (in the case of injection moulding) or the introduction of material into the mould, the end of the injection phase, the start of the maintenance of pressure in the mould or the command to release the purge gas that the injection press sends to the mould after injection or the opening of the mould at the end of the cycle, each of which can determine a synchronization signal.

[0015] For example, the flow rate, i.e. the unit amount, of the temperature-regulating liquid in the molding die can be varied over time to vary the amount of heat exchanged between the die and the temperature-regulating liquid over time. Thus, by knowing the temperature over time of the forming material in the die, in other words the temperature of the die if not regulated by the temperature-regulating liquid, it is possible to program an appropriate change in the amount of temperature-regulating liquid circulating in the die. A favorable temperature regulation of the die can be obtained by supplying the appropriate amount of temperature-regulating liquid at the appropriate moment in order to achieve a desired die temperature profile over time. It should be noted that this control operation does not envisage an inverse control of the die temperature, but simply the supply of a given amount of temperature-regulating liquid at the required moment, which is pre-determined, i.e. programmed, before the start of the process.

[0016] Indeed, taking as an example a forming cycle of an industrial process, for example moulding, which comprises a closing of the mould, a forming phase and then an opening of the mould, the machine according to the invention makes it possible to introduce into the mould a flow of temperature regulating liquid, the flow rate of which varies in a predetermined way over time in the forming cycle, said variation being synchronized with the forming cycle, for example on the basis of a synchronisation signal from the moulding plant. For example, the predetermined moment of the moulding process at which the above-mentioned synchronization takes place may be the moment when the mould is closed, which is associated with the signal leading to the closing of the mould, i.e. the start of the forming phase.

[0017] For example, the mold may be associated with a sensor that detects the opening and closing of the mold and may be operatively connected to an electronic device that can instruct the machine to coincide or synchronize the initiation of a time-based pump flow rate change profile with the closing of the mold.

[0018] Likewise, as mentioned above, the given moment of the molding process at which said synchronization takes place can be related to other moments in the forming cycle than the moment of mold closing: for example, in the case of injection molding, the synchronization may be performed at the start of the injection phase, or at the start of a typical phase of the molding process involving "post-pressurization", i.e. the period immediately after injection during which pressure is maintained for a certain time, or when a command occurs to release the purge gas that an injection press typically sends to the mold after injection, or when a command occurs to switch from mold opening to mold closing.

[0019] The fact that the right amount of temperature-regulating liquid can be sent at the most appropriate time, instead of always using a constant flow rate of temperature-regulating liquid, allows the optimization of the operating temperature. For example, when the flow rate of the temperature-regulating liquid (cooling liquid in this case) is varied to cool the mold, the operating temperature of the temperature-regulating liquid can be much lower than if the flow rate is constant. In fact, a low flow rate of temperature-regulating liquid can be used at a low (constant) operating temperature when the need for cooling is small, and a high flow rate of temperature-regulating liquid can be used (at the same low constant temperature) when a lot of heat exchange is required, i.e. when the need for cooling is large. In the case of a conventional constant flow rate, the operating temperature cannot be lowered because the mold would be cooled too much, and therefore a higher average temperature must be used (for a longer period than in the innovative variable flow rate system described herein).

[0020] Preferably, the pump is of the type having a variable speed impeller, whereby varying the speed of the variable speed impeller varies the flow rate of the pump, and thus a predetermined time-based pump flow rate variation profile can correspond to a predetermined time-based impeller speed variation profile.

[0021] More preferably, the pump comprises an inverter adapted to manage the rotational speed of a variable-speed impeller of the pump, whereby a predefined time-based pump flow rate variation profile can be made to correspond by the inverter to a predefined profile of the power supply frequency variation of the electric motor of the pump. When compared to known technology of pumps with impellers whose rotational speed can be varied, for example, by a servomotor, the use of a pump with an inverter as shown here proves to be particularly innovative and advantageous. The servomotor is an electromechanical device that acts directly on the fluid in the pump, and the inverter is simply a power frequency converter that allows the pump to be managed in an optimal and simplified way with respect to the variation of its speed.

[0022] The use of a pump with a variable speed impeller allows better control of the variation in the flow rate of the temperature regulating liquid, which allows the use of lower operating temperatures and shorter molding cycles, thus obtaining better results in terms of heat exchange at the most appropriate moment of the molding cycle.

[0023] In a preferred embodiment, the heat exchange unit for the temperature regulating liquid is arranged between the return part and the pump, i.e. the pump is downstream of the heat exchange unit. In another embodiment, the pump can be arranged upstream of the heat exchange unit, i.e. the pump is arranged between the return part and the heat exchange unit.

[0024] According to a preferred embodiment, downstream of the heat exchange unit and upstream of the access area for the temperature regulating liquid in the mould, a heating device is provided for heating the temperature regulating liquid, whereby the temperature regulating liquid can be heated and, if necessary, the temperature of the temperature regulating liquid entering the heating device can be raised to the value of the operating temperature. Preferably, the heating device is downstream of the pump.

[0025] According to a preferred embodiment, the hydraulic circuit comprises a tank for the temperature-conditioning liquid, interposed between the pump and the heat exchange unit, the tank being (a) at ambient pressure or (b) closed and held at a given pressure range not including ambient pressure, preferably operatively connected to a branch for loading the temperature-conditioning liquid from a supply network external to the machine.

[0026] According to a preferred embodiment, the machine is integrally equipped inside with a thermal conditioning device adapted to supply the heat exchange unit with a thermal conditioning liquid adapted to exchange heat with the temperature regulating liquid. Preferably, the thermal conditioning device together with the heat exchange unit forms a refrigeration system integrated in the machine. The refrigeration system comprises, for example, a compressor, a condenser, an evaporator and a storage tank, each of which has variable dimensions calculated as a function of the required refrigeration power. If the temperature regulating liquid is a cooling liquid, the heat exchange unit is in fact the evaporator of the refrigeration system. And if the temperature regulating liquid is a heating liquid, the heat exchange unit is a condenser.

[0027] In another embodiment, the machine comprises a thermal conditioning device formed by a refrigeration system integrated in the machine, the refrigeration system comprising, for example, a compressor, a condenser, an evaporator and an expander, each of which has a variable dimension calculated as a function of the required refrigeration power, adapted to supply a heat exchange unit with a thermal conditioning liquid adapted to exchange heat with the temperature conditioning liquid, in this case the thermal conditioning device and the heat exchange unit are separate elements and are connected only by a pipe for passing the thermal conditioning liquid.

[0028] In another embodiment, the thermal conditioning unit of the machine is operatively connected to a source of thermal conditioning fluid external to the machine, for example, the thermal conditioning unit is a heat exchanger interconnected with an external refrigeration and heating source derived from a centralized system of the plant in which it is installed, or is connected to an external refrigeration system.

[0029] According to another aspect, the invention relates to a machine for temperature control of a part of an industrial plant adapted for forming products according to one or more of the following clauses:

[0030] Supplementary Note 1: A machine for temperature control of a part of an industrial plant adapted for forming a product, comprising at least one temperature-regulating hydraulic circuit adapted to be operatively connected to a product-forming part of the industrial plant adapted for forming a product, a temperature-regulating fluid circulating in the hydraulic circuit, the hydraulic circuit comprising: a recirculation pump for the temperature control liquid, of the variable flow type; a delivery section downstream of the pump for delivering the temperature-regulating fluid from the hydraulic circuit to a product-forming section of an industrial plant; a return section for returning the temperature-regulating fluid from the product forming section of the industrial plant to the hydraulic circuit; a heat exchange unit for a temperature regulating fluid, arranged between the return part and the pump, in which the temperature of the temperature regulating fluid is regulated; the machine further comprising an electronic control and management device configured with at least one value for an operating temperature of the temperature regulating liquid and with at least one predetermined time based pump flow rate variation profile according to which, upon receiving a synchronization signal at a predetermined instant of an industrial process of product formation in the part of the plant to be temperature regulated, the pump moves the temperature regulating liquid over time at a variable flow rate based on the predetermined flow rate variation profile.

[0031] Appendix 2: The machine of Appendix 1, wherein the pump is of a type having a variable speed impeller, whereby varying the speed of the variable speed impeller varies the pump flow rate, and wherein a predetermined time-based pump flow rate change profile corresponds to a predetermined time-based impeller speed change profile.

[0032] Appendix 3: The machine of Appendix 1, wherein the pump comprises an inverter adapted to manage the rotational speed of a variable speed impeller of the pump, whereby a predetermined time-based pump flow rate change profile is caused by the inverter to correspond to a predetermined profile of pump power supply frequency change.

[0033] Appendix 4: A machine according to any one of appendices 1 to 3, wherein downstream of the heat exchange unit and upstream of the delivery section to the product forming section of the industrial plant, a heating device for the temperature control liquid is provided, adapted to heat the temperature control liquid, which, if necessary, heats the temperature control liquid to an operating temperature when the temperature of the temperature control liquid entering the heating device is low, and preferably the heating device is downstream of the pump.

[0034] Appendix 5: A machine according to any one of appendices 1 to 4, wherein the hydraulic circuit comprises a tank for temperature regulating fluid interposed between the pump and the heat exchange unit, the tank being at ambient pressure or closed and held in a pressure range not including ambient pressure, preferably the tank being operatively connected to a branch for loading temperature regulating fluid from a supply network external to the machine.

[0035] Appendix 6: A machine according to any one of appendices 1 to 5, comprising a thermal conditioning device adapted to supply a thermal conditioning liquid adapted to exchange heat with the temperature regulating liquid to the heat exchange unit, preferably comprising: Together with a heat exchange unit it forms a refrigeration system that is entirely within the machine, the heat exchange unit forming a compressor, condenser or evaporator for the refrigeration system; a refrigeration unit which is a separate element from the thermal conditioning unit, the refrigeration unit being adapted to supply the thermal conditioning unit with a thermal conditioning fluid for conditioning the thermal conditioning fluid by heat exchange.

[0036] Appendix 7: A machine according to any one of appendices 1 to 5, wherein the heat exchange unit has an inlet pipe and an outlet pipe for supplying a heat conditioning liquid and is operably connected to a heat conditioning system external to the machine.

[0037] Appendix 8: A machine according to any one of appendices 1 to 7, wherein the delivery and return parts for the temperature regulating liquid are adapted to be operatively connected to pipes in the mould so as to be able to deliver the temperature regulating liquid into the mould, to regulate its temperature, and to return the reconditioned temperature regulating liquid.

[0038] Appendix 9: A machine according to any one of appendices 1 to 8 adapted to operate cyclically, the electronic control and management device comprising: receiving a signal from the production part of an industrial plant to be temperature-regulated, The signal can be synchronized with the flow rate change profile for the pump, so that from a given moment during the machine's operating cycle, the pump's flow rate can be changed in a predetermined way.

[0039] Item 10: The machine according to item 9, adapted to cool the mould, the machine is adapted to receive a closing signal for a mould which is to be temperature regulated; The thermoregulating liquid is pumped to the mold at a constant working temperature during the molding phase, and for values ​​of temperature lower than the working temperature, a phase of adjusting the temperature of the thermoregulating liquid before feeding it to the mold is envisaged; In a molding cycle including close-open-close of the mold, a flow rate change profile for the temperature control fluid entering the mold is synchronized with the molding cycle based on a mold close signal to provide a low initial flow rate value for gradually cooling the mold and a subsequent high flow rate value greater than the initial flow rate value for more intense cooling of the mold.

[0040] Item 11: The machine of item 10, wherein if the machine does not receive a closure signal from the mold within a given time interval, Change the pump flow rate profile to keep the flow rate low to gradually cool the mold. the value for the working temperature of the temperature-regulating liquid entering the mould preferably corresponds to the temperature value of the mould at the moment the mould is closed, · Following a signal-free time interval, when a new mold closure signal is received, the flow rate change profile of the temperature regulating fluid entering the mold returns to the predetermined profile for a normal molding cycle. [Brief description of the drawings]

[0041] The invention will become clearer from the following description and the accompanying drawings which show non-limiting examples of the invention. [Figure 1] FIG. 1 shows a layout of the machines according to the invention in relation to a moulding plant. [Diagram 2]2 is a graph showing several molding cycles of the plant shown in FIG. 1, with time on the X-axis and mold temperature, temperature of the thermoregulating fluid, and flow rate of the thermoregulating fluid on the Y-axis. [Diagram 3] 2 is a graph showing several molding cycles of a molding plant having a machine for temperature regulation of the mold according to the prior art, such as that shown in FIG. 1; [Figure 4] 3 is a graph similar to that shown in FIG. 2, but showing a waiting phase without molding in the plant shown in FIG. [Diagram 5] 2, but showing the start phase of a new molding cycle after a waiting phase without molding in the plant shown in FIG. [Figure 6] 2 is a machine layout according to the invention with variations with respect to the situation shown in FIG. 1 . [Figure 7] 7 is a machine layout according to the invention with variations with respect to the situation shown in FIGS. 1 and 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] With reference to the above mentioned figures, a machine for temperature control of a moulding mould according to a first embodiment of the invention is indicated generally by the reference numeral 10.

[0043] The machine 10 is installed in a plant for the production of moulded articles, indicated as a whole by the reference A, for example a moulding plant of the type which involves the injection of plastic material into a mould. This plant A comprises a mould, indicated by the reference B, and an injection press, indicated by the reference C.

[0044] The machine 10 comprises a hydraulic circuit 11 adapted to thermostat (in this case cooling) the mould B by means of a thermostating fluid (i.e. cooling fluid), preferably water (but which may also be other liquids such as oil and water with glycol), The hydraulic circuit 11 is therefore operatively connected to the mould B for circulating the thermostating fluid therein.

[0045] More specifically, the hydraulic circuit 11 includes a pump 12 for circulating a temperature control liquid of a variable flow rate type (described in detail below).

[0046] Downstream of the pump 12 there is a first part 13 for delivering temperature regulating fluid from the hydraulic circuit to the mould B.

[0047] Advantageously, the hydraulic circuit 11 comprises a second portion 14 for returning the temperature conditioned liquid from the mould back to the hydraulic circuit.

[0048] The hydraulic circuit 11 also comprises a heat exchange unit 15 for a thermoregulating liquid, arranged between the return part 14 and the pump 12. Here, in this example, the thermoregulating liquid is thermoconditioned so that it can release the heat gained in the mould during its cooling and return to a suitable temperature for cooling the mould during the subsequent moulding cycle.

[0049] In this embodiment, the heat exchange unit 15 has a first interface side associated with the passage of the temperature regulating liquid and a second interface side adapted to receive heat released by the temperature regulating liquid. Here, the second interface side is operatively connected to a heat conditioning device 16 adapted to supply the heat exchange unit 15 with a heat regulating liquid adapted to exchange heat with the temperature regulating liquid. For example, the heat conditioning device forms a refrigeration system together with the heat exchange unit. For example, the refrigeration system 15-16 includes a compressor, a condenser, an evaporator, and an expander, and specifically, the heat exchange unit 15 corresponds to an evaporator. This allows the liquid from the mold to be cooled.

[0050] As mentioned above, in another embodiment, the thermal conditioning device 16 is a separate system from the heat exchange unit 15 (again, e.g. a refrigeration system comprising a compressor, a condenser, an evaporator and an expander) and is adapted to supply the heat exchange unit 15 with a thermal conditioning liquid adapted to exchange heat with a temperature conditioning liquid. In this case, the thermal conditioning device 16 and the heat exchange unit are separate elements and are connected only by a pipe for passing the thermal conditioning liquid.

[0051] The hydraulic circuit 11 also comprises a tank 17 for thermoregulating fluid, interposed between the pump 12 and the heat exchange unit 15. In this embodiment, the tank 17 is at ambient pressure. In another embodiment, the tank 17 is closed and kept at a given pressure range not including ambient pressure. Advantageously, the tank 17 is operatively connected to a branch 18 for charging with thermoregulating fluid from a supply network external to the machine, advantageously closed by a charging valve 18A.

[0052] Downstream of the heat exchange unit 15 and upstream of the section 13 for delivering the temperature-regulating liquid to the mould, a heating device 20 is provided for heating the temperature-regulating liquid, whereby the temperature-regulating liquid is heated, if necessary, to the value of the operating temperature (described in more detail below). Preferably, the heating device 20 (for example of the Joule effect heating type against an electrical resistance or the like) is arranged between the pump 12 and the delivery section 13. For example, the heating device 20 is associated with a temperature probe 20A capable of measuring the temperature of the temperature-regulating liquid leaving the heating device and activating the heating device if the measured temperature is inappropriate.

[0053] As mentioned above, the pump 12 is a variable flow rate type pump. More preferably, the pump is an electric pump of the type with a variable speed impeller, the variability of the flow rate being obtained by varying the speed of the variable speed impeller. To vary the speed of the variable speed impeller of the pump 12, the pump is equipped with an inverter 12A, which allows the power supply frequency of the electric motor of the pump to be varied and thus the impeller speed to be varied. By using a pump with a variable speed impeller, the variation of the flow rate of the temperature control liquid can be largely controlled, which allows better results in terms of heat exchange at the most suitable moment in the molding cycle.

[0054] Advantageously, the machine 10 also comprises an electronic control and management device 30, for example a PLC, operatively connected to the various components of the machine (pump 12, heating device 20, heat exchange unit 15, etc.).

[0055] At least one value for the operating temperature Te of the temperature adjusting liquid and at least one predetermined time-based flow rate change profile Pl of the pump 12 are set in the electronic device 30. Thus, when a synchronization signal is received at a predetermined moment of the molding process in the mold B, the pump 12 moves the temperature adjusting liquid at a variable flow rate based on the predetermined time-based flow rate change profile. Since the fluctuation in the pump flow rate is generated by the change in the impeller speed, i.e., the power supply frequency of the electric motor of the pump, the predetermined time-based pump flow rate change profile will correspond to the predetermined time-based impeller speed change profile, i.e., the predetermined power supply frequency change profile of the electric motor of the pump by the inverter.

[0056] For example, the synchronization signal at a given moment of the molding process in mold B may be a signal from a sensor 40 operatively connected to the electronic device 30 for detecting the closing / opening of mold B. This enables the electronic device to instruct the machine to coincide or synchronize the start of the time-based pump flow rate variation profile Pl with the closing of the mold, i.e., the start of the forming phase.

[0057] By knowing the temperature of the forming material in mold B over time, in other words what the temperature of the mold would be if not regulated by the temperature regulating liquid, it is possible to program an appropriate change in the amount of liquid circulating in the mold, thereby obtaining a preferred temperature regulation of the mold by providing the preferred amount of liquid at the right moment to achieve the desired mold temperature profile over time.

[0058] It should be noted that the sensor 40, such as a microswitch, may be applied to the mold B and may be part of the machine 10.

[0059] It should also be noted that the control operation does not contemplate the inverse control of the mold temperature, but simply the delivery of a given amount of temperature regulating fluid at a required moment, pre-determined (i.e., programmed) before the start of the process. In effect, the electronic device 30 is provided with a "recipe," i.e., settings for a set of predetermined operating parameters based on a particular molding process.

[0060] Indeed, for a forming cycle of a given molding process, which includes a mold closing, a forming phase, and a subsequent mold opening, the machine introduces a flow of temperature regulating fluid into the mold at a flow rate that varies over the time of the forming cycle, where the variation is synchronized with the forming cycle based on, for example, a mold closing signal from a sensor.

[0061] FIG. 2 is a graph illustrating an example of a molding process including the injection of a plastic material into a mold B.

[0062] In this example, the injection press cycle lasts 33 seconds, i.e., every 33 seconds the mould is closed, the plastic material is injected under pressure, the mould is held under pressure for a period of time, the mould is opened during which there is a wait period during which the part is removed, and then the mould is closed again and the cycle begins again.

[0063] The hydraulic circuit 11 of the machine 10 is connected to the cooling ducts of the mould B by a delivery section 13 and a return section 14 .

[0064] In this case, the temperature control liquid sent to the mould for cooling has an approximately constant operating temperature Te, for example 23°C, the variation interval of this value being less than ±3°C, more preferably less than ±1°C.

[0065] In FIG. 2, the temperature of the cooling water sent to the mold is indicated by a dashed line.

[0066] The operating temperature is ensured, for example, by a heating device 20 (or by the heat exchange unit 15 if there is no heating device). For example, a temperature probe 20A measures the temperature of the cooling water leaving the heating device, and if the temperature is lower than a set temperature Te, the heating device 20 heats the cooling water until it reaches the temperature Te.

[0067] Returning to the molding cycle, at time t0 the mold is closed and injection of the plastic material begins at time t1 (2 seconds after the mold is closed in the example shown in the graph), where the mold close / open signal is shown by the dashed line S.

[0068] As mentioned above, the electronic device 30 is loaded with a predetermined time-based flow rate change profile P1 for the pump 12 synchronized with the closing of the mold. At the moment t0, i.e. upon receipt of the mold closing signal (or after a certain delay time if so programmed), the electronic device 30 communicates with the inverter 12A to maintain the pump motor power supply frequency, i.e. the rotational speed of the pump impeller according to the preset profile. For example, during the first seconds, the pump speed, i.e. the flow rate of the cooling water, remains constant at a value V0 (corresponding to about 15% of the maximum speed of the pump impeller) and increases significantly from the moment t2 to a peak value V1 (reached at the moment t4) corresponding to 95% of the maximum speed of the pump impeller (in the graph the cooling water flow rate (liters / min) is shown by a continuous line). The pump speed (i.e., flow rate) then rapidly decreases again to the initial flow rate / speed V0 and remains constant until the end of the cycle. (Note that the change in pump motor power supply frequency may be stepped, i.e., passing from a particular frequency to the next without passing through an intermediate frequency; also note that the change in flow rate is apparently continuous and not stepped.)

[0069] The graph shown in Figure 2 also shows the evolution of the temperature of the mould (measured at the sample points) during the process cycle. This is indicated by a dashed double-dashed line. As shown in the figure, the temperature of the mould rises from the closing of the mould (for example from a value Ti of 75°C) until just after the end of the injection phase of the plastic material (t1) and then drops until just after the end of the post-pressurisation phase t3. On opening of the mould, at the moment t5, the mould temperature rises again until it reaches the initial temperature Ti of 75°C.

[0070] Figure 3 shows a graph for the molding of the same part (using the same mold) molded in the example graph shown in Figure 2, but using the conventional technique of cooling the mold by sending cooling water through the mold's cooling ducts. In the two examples, the starting temperature Ti (arrival of the mold in the molding cycle) is obviously the same. As can be easily seen in the second example shown in Figure 3, the flow rate of the cooling water is constant during the cycle, the working temperature Te is much higher than in the previous example (constant at about 60°C) and the cycle length is longer (about 40 seconds).

[0071] Returning to the machine according to the invention, if the moulding process is interrupted for any reason (eg stopping the injection press), the electronic control and management unit 30 changes the management parameters of the machine.

[0072] If there is no signal from the process for a time longer than the threshold Dtx, for example 15 minutes (meaning in the above example that the mold closing signal has not arrived), the electronic device 30 activates the standby mode at the moment tx (i.e. t0+Dtx), which keeps the mold in a preheated state.

[0073] In this regard, please refer to the example graph shown in FIG.

[0074] After the cycle end time (in the case of the above example, 33 seconds from time t0), if there is no signal from the process (e.g. a mold closing signal to start a new cycle) during the time interval Dtx, the electronic device 30 commands the heating device 20 to heat the temperature adjustment liquid to the preheating temperature Ti', e.g. the mold closing temperature Ti, i.e. 75°C. The pump flow rate, i.e. the speed of its impeller, is changed to a high value, e.g. the maximum possible speed value Vm (in any case a value higher than the value V1 envisaged during the cycle for maximum cooling effect), e.g. up to 100% of the possible speed (i.e. the maximum achievable flow rate). In this way, the mold is gradually heated and a new mold closing signal is awaited in order to start the molding cycle again as described above.

[0075] Upon receiving a new signal from the process (see graph in FIG. 5), the electronic device 30 changes the process parameters again at the instant t0′ and switches back to the production mode: the temperature of the cooling water thus goes from the preheating temperature Ti′ to the operating temperature Te for the start of the cycle (23° C. in the previous example).

[0076] The first cycle C1 after the wait / preheat period is "abnormal" because it takes time for the actual temperature of the cooling water to reach the new temperature Te.

[0077] The speed of the pump 12 naturally varies as a function of synchronization with the process, i.e. according to a preset time. Also, at the moment t4' of the cycle C1', there is a switch from "hard" cooling at speed V1 to "soft" cooling at speed V0 as defined above. From the start of the second molding cycle after the stop, the temperature is already approaching the operating temperature. The return to full operating process performance is obtained after 4-5 molding cycles, depending on various factors such as the dimensions of the mold, the power of the heating devices and heat exchange units, and the various heat dispersions.

[0078] In the embodiment described above, the machine 10 is substantially automated and provides substantially the following external connections to the machine: hydraulic connections to metal, application of microswitches 40 to metal, loading junction 18 to tank 18, electrical wiring of the machine to external systems, and any electronic cabling from the electronics to other parts of the plant.

[0079] In particular, the heat exchange unit 15 and the heat conditioning device 16 form an integrated system inside the machine.

[0080] As shown diagrammatically in FIG. 6, in another embodiment, the thermal conditioning device 16′ may be external to the machine 10 and may, for example, be part of a conditioning system within the plant in which the machine operates and may serve multiple users.

[0081] In this example, a machine is shown in which a single hydraulic circuit is connected to the mold, so that the temperature-conditioning fluid enters the mold at a given temperature and leaves the mold at a different temperature. Here, the mold is provided with a single heat exchange process (single flow of temperature-conditioning fluid at a given temperature from the mold). In another embodiment, such as the machine 100 shown in FIG. 7, the machine has several hydraulic circuits 11, 11', 11'', arranged in parallel with respect to each other, in order to distinguish the heat exchange options in different parts of the mold. The hydraulic circuits include pumps with delivery parts 13, 13', 13'', and return parts 14, 14', 14'', respectively, inverters 12, 12', 12'', heating devices 20, 20', 20'', and heat exchange units 15, 15', 15'', each of which is operatively connected to an electronic control and management device 20. The inlet and outlet portions of the second interface side of the thermal exchange units 15, 15', 15'' are connected in parallel with each other and operatively connected to the inlet and outlet for the thermal regulating fluid by a thermal regulating device 116 external to the machine 100 (although in alternative embodiments the thermal regulating device may be internal as in the embodiment shown in FIG. 1). The operation of the machine is substantially similar to that described above, with each of the thermal regulating fluids having its own temperature and flow rate profile. Their usage is synchronized with the others.

[0082] It should be noted that the above examples represent possible embodiments of the invention in a non-limiting manner, which may vary in form and arrangement without departing from the scope of the underlying concept of the invention. The reference signs in the appended claims are intended only to facilitate comprehension in view of the above description and the accompanying drawings, and do not limit the scope of protection.

Claims

1. A machine for temperature control of a product-forming part of an industrial plant including a mould for the formation of a product, said machine comprising at least one thermoregulating hydraulic circuit adapted to be operatively connected to said product-forming part of said industrial plant for the formation of a product, a thermoregulating fluid circulating through said hydraulic circuit, The hydraulic circuit includes: a pump for recirculation of said temperature regulating liquid, of the variable flow type; a delivery section downstream of the pump for delivering the temperature regulating liquid from the hydraulic circuit to the product forming section of the industrial plant; a return section for returning the temperature regulating fluid from the product forming section of the industrial plant to the hydraulic circuit; a heat exchange unit for said temperature regulating liquid, in which said temperature regulating liquid is temperature regulated; Equipped with The machine further comprises an electronic control and management device, the electronic control and management device being configured with at least one value for an operating temperature of the temperature regulating liquid and at least one predetermined time-based pump flow rate variation profile, the pump moving the temperature regulating liquid over time at a variable flow rate based on the pump flow rate variation profile when receiving a synchronization signal at a predetermined moment of the industrial process of the product formation in the product formation part of the industrial plant to be temperature regulated according to the pump flow rate variation profile, the machine being adapted to operate cyclically; The electronic control and management device includes: receiving a signal from the product formation portion of the industrial plant that is to be temperature regulated; - the signal can be synchronized with a flow rate change profile for the pump, so that from a given moment during the operating cycle of the machine, the flow rate of the pump can be changed in a predetermined manner; the machine being adapted to cool the mould; the machine is adapted to receive a closing signal for the mould from the product forming part of the industrial plant comprising the mould which is subject to temperature regulation; said temperature control liquid is fed by said pump to the mould during a moulding phase at a constant working temperature, and for temperature values ​​below said working temperature, a phase of adjusting the temperature of said temperature control liquid before feeding it to the mould is provided, in a molding cycle including close-open-close of the mold, the pump flow rate change profile for the temperature regulating liquid entering the mold is synchronized with the molding cycle based on the closure signal to provide a low initial flow rate value for gradually cooling the mold and a subsequent high flow rate value greater than the initial flow rate value for more intense cooling of the mold. machine.

2. 2. The machine of claim 1, wherein the pump is of a type having a variable speed impeller whereby varying the speed of the variable speed impeller varies the flow rate of the pump, and wherein the predetermined time-based pump flow rate change profile corresponds to a predetermined time-based impeller speed change profile.

3. 2. The machine of claim 1, wherein the pump comprises an inverter adapted to manage the rotational speed of the variable speed impeller of the pump, whereby the predetermined time-based pump flow rate variation profile corresponds by the inverter to a predetermined profile of power supply frequency variation of the pump.

4. The machine according to any one of claims 1 to 3, wherein downstream of the heat exchange unit and upstream of the delivery part of the industrial plant to the product forming part, a heating device for the temperature regulating liquid is provided adapted to heat the temperature regulating liquid, which, if necessary, heats the temperature regulating liquid to the operating temperature if the temperature of the temperature regulating liquid entering the heating device is low, and preferably, the heating device is downstream of the pump.

5. A machine according to any one of claims 1 to 4, wherein the hydraulic circuit comprises a tank for the temperature regulating liquid interposed between the pump and the heat exchange unit, the tank being at ambient pressure or closed and held in a pressure range not including ambient pressure, preferably the tank being operatively connected to a branch for loading the temperature regulating liquid from a supply network external to the machine.

6. Equipped with a heat regulator, the thermal conditioning device is adapted to supply to the heat exchange unit a thermal conditioning liquid adapted to exchange heat with the temperature conditioned liquid; Preferably, the heat conditioning device together with the heat exchange unit forms a refrigeration system entirely within the machine, the heat exchange unit forming a condenser or evaporator for the refrigeration system; or the thermal conditioning device is a refrigeration unit which is a separate element from the thermal conditioning unit, the refrigeration unit being adapted to supply the thermal conditioning unit with a thermal conditioning liquid for conditioning the temperature conditioning liquid by heat exchange; A machine according to any one of claims 1 to 5.

7. A machine according to any one of claims 1 to 5, wherein the heat exchange unit has inlet and outlet pipes for supplying a heat conditioning liquid and is operatively connected to a heat conditioning system external to the machine.

8. A machine according to any one of the preceding claims, wherein the heat exchange unit for the temperature conditioned fluid is arranged between the return part and the pump.

9. A machine according to any one of claims 1 to 8, wherein the delivery and return parts for the temperature conditioned liquid are adapted to be operatively connected to pipes in the mould so as to be able to deliver the temperature conditioned liquid into the mould, to be temperature conditioned, and to return the reconditioned temperature conditioned liquid.

10. 10. The machine according to any one of claims 1 to 9, wherein the product forming part of the industrial plant comprises a mould which is subject to regulation, and the machine is adapted to regulate a temperature of the mould, said regulation being cooling or heating or both.

11. if the machine does not receive a signal from the product forming part of the industrial plant that includes the molding tool to be temperature regulated for a given time interval, modifying the pump flow rate profile to maintain a low flow rate in order to gradually cool the mold; the value for the working temperature of the thermoregulating liquid entering the mould is preferably raised to a value which corresponds to the value of the temperature of the mould at the moment when the mould is closed; - when a new signal is received following the time interval without the signal, the flow rate profile of the temperature regulating fluid entering the mold returns to a predetermined profile for a normal molding cycle; A machine according to any one of claims 1 to 10.

12. A machine according to any one of claims 1 to 11, wherein the synchronization signal at a given moment of the industrial process of product formation in the product-forming part of the industrial plant that is subject to temperature regulation is a mould closing signal, or a mould opening signal, or a signal to start the injection of forming material into the mould, or a signal to finish the injection of forming material into the mould, or a signal from an injection press to release purge gas into the mould after injection, or in general any signal coming from the industrial plant that is related to the same moment of a forming cycle, preferably a phase of the forming process that is always repeated between the opening and closing of the mould.

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