CS272488B1 - Device for heating and cooling molds for plastic injection and die casting - Google Patents

Abstract

The solution concerns a device for heating and cooling a mold. The device consists of a cooling and heating circuit. The cooling circuit consists of a reversing pump, sucking in the cooling medium at the outlet of the cooler and pushing the medium into the cooling channels of the mold through the heating coil in the return heating medium tank and the cooler to the pump inlet. The second branch from the pump is connected via a plastic accumulator to a closed tank with heating of the heating medium and via a pipe extending below the level of the heating medium, to the heating channels of the mold and to the return heating medium tank. The return heating medium tank is connected by a gradient to the closed heating medium tank.

Description

1 CS 272 48S B1

The invention relates to a device for heating and cooling a mold for the injection of plastics alloys of metals under pressure. For molds for injection molding and die casting, the form of quasi-minimum thermal stress must be the beginning of injection, rasp. casting preheats to the right temperature. In the course of injection, rasp. casting, the mold must be heated in some places and cooled in some places.

The hitherto known mold heating and cooling devices comprise a detached circuit with molded cooling channels in the mold, and a cooling medium and a cooling mold dump and a separate circuit with molded heater channels, a heating medium, and a reciprocating pump for pumping the hot mold to heat the mold.

Known devices for heating and cooling molds have one circuit 3 for cooling and for heating a mold with a core wand and core medium, which is either cooled or heated during circulation.

The disadvantage of the first mentioned devices is the need for two wanders, one for the hot medium. The disadvantage of the latter devices is only the core of the cooling circuit and the heating of the mold, which does not compromise the technological requirements for cooling and solidification of moldings, rasp. castings which, in the course of cooling and solidification, achieve high quality moldings and castings, some of which must be cooled; some heated. Another disadvantage is the use of only one medium for cooling and for heating the mold, which cannot be switched optimally for cooling and mold properties.

The above drawbacks are eliminated by the apparatus for heating and cooling the mold according to the invention, the essence of which is that; The feed pump is connected via a plastic accumulator to a closed heating medium tank and a tube extending below the level of the heater to the heating ducts in the mold and further to the heater reservoir tank connected to the closed medium of the heating medium. Another rave pump is connected to the passage of the cooling ducts in the form of a heater coil of the heater medium and to the radiator, the inlet of the reversing pump is connected.

The mold heating and cooling apparatus according to the invention combines in one device the advantages of the two known devices described above. It retains two spaced circuits, especially for, cooling and especially for heating the mold, thus meeting the technological requirements for cold and solidification of the moldings, rasp. casting in order to achieve their quality and at the same time benefit from the use of one reversible pump for refrigerant. In contrast to the second known devices, it has the advantage of using a cooling medium with optimum cooling properties for cooling the mold and the heating medium with optimum heating properties.

An exemplary embodiment of a device according to the invention is shown schematically in the accompanying drawing.

The passage of the mold cooling passage 11 is connected at one end to a two-pole solenoid valve 2, connected to a control system 3, to a cavity pump 4 with an electromotor 5, and a second-position electromagnetic valve 6 connected to the control system 3 is connected to the preheating pump. a spiral 7 disposed in the tank 8 of the heater medium of the heater medium and 3a inlet to the cooler 9, the outlet of which is connected to the inlet of the reversing pump 4. The inlet of the reversing pump 4a is connected to an axial vessel 10 with a float sensor 11 connected on the control system 3. The cooling circuit 12 is provided with an independent cooling circuit 12 in which a two-position solenoid valve 13 is mounted. The temperature sensor 14, connected to the control system 3 is located at the outlet of the cooling channels 11 of the mold. safety valve 15 connected. Furthermore, a 2-position el an ectro-magnetic valve 15 connected to the control system 3, a plastic accumulator 17 on the side of the liquid which is connected to the closed tank 18 of the heating medium from the gas side, connected to the passage of the heating channels 20 of the mold and then to the tank 8 of the door.

Claims (1)

CS 272 488 B1 of the heating medium which is connected via a two-position solenoid valve 21 connected to the control system 3 to a closed heating medium tank 18. A temperature sensor 22 connected to the control system 3 is located at the outlet of the heating channels and channels 20. In the closed heating medium tank 18, an electrical heating device 23 and a heating medium temperature sensor 24 connected to the control system 3 are located. A fluid sensor 25 connected to the control system 3 is located in the medium. In thermally retracting mold; for example, a mold melt material, the cooling medium in the mold cooling channels 1 is heated and flowed through the preheater 7 in the tank 8 of the heater medium door preheater. The coolant flow is provided by the reverse pump 4 connected to the electric motor 5. The inlet of the reverse pump 6 is connected to an expansion vessel 10 serving to compensate for the volume changes of the coolant. The float sensor 11 at the level of the medium in the expansion vessel serves to protect the pump 4 against idling. The safety out-feil15, connected at the pump outlet 4, is the protection of the device in case of its failure. The temperature sensor 14 at the outlet of the mold cooling channels 2 gives a signal to turn off the cooling circuit and to turn on the heating circuit via the control system 3. To this signal, the electromagnetic valve 13 switches off and the cooling circuit 12 is closed by the cooler 9, the electromagnetic valve 6 is switched off, thereby closing the cooling circuit and turns on 3a electromagnetic valve 16 to open the heating circuit. The medium from the reverse pump 4 is pushed into the plastic accumulator 17, thereby moving the piston upward; the pressure above the piston in the accumulator 17 increases and above the heating medium level in the closed tank 18 and the heating medium flows through the tube 19 to the mold heating channels 20. The heating medium temperature s sensed by the temperature sensor 24 provides a signal for switching the electric heater 23 on and off. The solenoid valve 13 is switched on at the signal of the heating medium temperature sensor 22, thereby opening the cooling circuit 12 of the radiator 9, turning the pump 4 for a short set time. thereby moving the accumulator piston 17 downwards, the pressure in the closed tank 18 decreases and the heating medium flow into the heating channels 20 is interrupted. After the set time has elapsed, the solenoid valve 16 is switched off, the electromagnetic valve 6 is switched on and the pump 4 is reversed. is switched to normal, whereby the pump 4 pushes the cooling medium into the cooling channels 2 of the mold. Upon raising the level of the heater media doorman and the reservoir 8, the float sensor 25 is switched on to give a signal to turn the reverse pump on for a set short time. Thus, if the heating circuit is in operation and thereby displacing the accumulator piston 17 downwards, the pressure above the piston and above the heating medium in the closed tank 18 decreases and the solenoid valve 21 is switched on, thereby allowing the medium to flow into the closed tank 18. Device According to the invention, injection molding, pressure casting of metals and heating and cooling of other thermally stressed tools can be advantageously used for heating and cooling foriempre. OBJECT OF THE INVENTION c Device for heating and cooling molds for injection molding and casting of metal under pressure, consisting of a control system, a cooling circuit 3 with a cooler and an expansion vessel, a safety valve, a coolant temperature sensor, a heating coil of the media and a heating circuit, characterized in that the reverse pump (4) is connected via a solenoid valve (2) to the cooling channels (1) of the mold, the outlet being connected via a cooler (9) to the inlet of the reverse pump (4), a solenoid valve (16) and a plunger accumulator (17) to a closed tank of the heating medium (18), the sensor of which (24) of the heating medium and the electrostatic fluid (3) are connected to the control system (3) and a tube (19) and a heating mode for the mold heating channels (20), at the outlet of which the temperature sensor (22) is connected to the control system (3), and the heats are connected to the control system (3) to a door heater media reservoir (8), the float level sensor (25) of which is connected to a control system (3) and a heater connected via a solenoid valve (21) to a closed heating medium tank (18). 1 drawing