JP7304596B2 - Temperature control device and heating control method - Google Patents

Description

The present invention relates to a temperature control device and a heating control method.

A mold is used in an injection molding machine for injection-molding a molded product using a synthetic resin such as plastic. A mold for injection molding has a cavity, which is a space filled with molten plastic, and a channel through which a medium for cooling and solidifying the molten plastic flows. Accurately maintaining the temperature of the mold at a required temperature is important for improving the precision of molded products, and a mold temperature controller is used.

In such a mold temperature controller, heating and cooling of the mold are alternately repeated. As a result of the thermal energy of the steam used for heating being transferred to the mold, the steam undergoes a phase change to water and drainage is generated. Such drain is discharged through a discharge valve (see Patent Document 1).

Japanese Patent Application Laid-Open No. 2003-200431

However, when the amount of drain accumulated in the medium flow path inside the mold increases, the time required for the temperature of the mold to reach the set temperature is delayed. Also, depending on the amount of collected drain, the temperature may drop without reaching the set temperature.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a temperature control device and a heating control method capable of preventing a delay in reaching a set temperature and shortening a cycle time. do.

In the temperature control device according to the present invention, a medium feeding pipeline for supplying steam as a heating medium is connected to the inlet side, the flowing medium is discharged, and a pipeline in which a discharge valve is interposed is connected to the outlet side. A temperature control device for controlling the temperature of an object having a medium flow path, comprising: a temperature acquisition unit for acquiring the temperature of the object at predetermined intervals ; and a state in which steam is supplied to the object to heat it. a temperature rise rate calculation unit for calculating a temperature rise rate for each predetermined interval of the object based on the temperature acquired by the temperature acquisition unit; a threshold value setting unit for setting a predetermined threshold; a control unit that controls opening and closing of the discharge valve based on the temperature increase rate calculated by the calculation unit, wherein the temperature increase rate calculation unit determines that the temperature of the object is lower than the set temperature of the object. A first temperature rise rate at the first temperature is calculated, and the threshold value setting unit determines a relationship between the temperature of the object and the rate of change of the temperature rise rate, which is predetermined according to the temperature of the heating medium. The temperature rise rate at the set temperature calculated based on the change rate of the temperature rise rate at the set temperature calculated from and the first temperature rise rate is set as the threshold value, and the The controller opens the discharge valve for a required time when the temperature increase rate calculated by the temperature increase rate calculator is smaller than the threshold value.

In the computer program according to the present invention, a medium feeding pipeline for supplying steam as a heating medium is connected to the inlet side, the flowing medium is discharged, and a pipeline interposed with a discharge valve is connected to the outlet side. A computer program for causing a computer to control the temperature of an object having a medium flow path, wherein the computer acquires the temperature of the object at predetermined intervals, and supplies steam to the object. a process of calculating a temperature increase rate for each predetermined interval of the object based on the acquired temperature in a state where the object is heated by heating; and the set temperature calculated from the relationship between the temperature of the object and the rate of change of the temperature rise rate, which is predetermined according to the temperature of the heating medium. a process of setting the temperature increase rate at the set temperature calculated based on the change rate of the temperature increase rate at the time and the first temperature increase rate as a threshold, and the temperature increase rate at each predetermined interval is smaller than the threshold value, a process of opening the discharge valve for the required time is executed.

In the heating control method according to the present invention, a medium feeding pipeline for supplying steam as a heating medium is connected to the inlet side, the flowing medium is discharged, and a pipeline in which a discharge valve is interposed is connected to the outlet side. A heating control method using a temperature control device for controlling the temperature of an object having a medium flow path, wherein a temperature acquisition unit acquires the temperature of the object at predetermined intervals, and supplies steam to the object. A temperature rise rate calculation unit calculates a temperature rise rate for each predetermined interval of the object based on the obtained temperature, and the temperature of the object is lower than the set temperature of the object. The temperature rise rate calculation unit calculates a first temperature rise rate at the first temperature, and the rate of change of the temperature of the object and the rate of change of the temperature rise rate is predetermined according to the temperature of the heating medium. A threshold value setting unit sets the temperature increase rate at the set temperature calculated based on the change rate of the temperature increase rate at the set temperature calculated from the relationship and the first temperature increase rate as a threshold. Then, if the temperature increase rate calculated by the temperature increase rate calculation unit is smaller than the threshold value, the control unit that controls opening and closing of the discharge valve based on the calculated temperature increase rate keeps the discharge valve open for the required time. Open during

According to the present invention, the cycle time can be shortened because the delay in reaching the set temperature can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing an example of a configuration of a mold temperature controller as a temperature control device of this embodiment; FIG. 2 is a schematic diagram showing an example of mold temperature control by the mold temperature controller of the present embodiment. FIG. 5 is an explanatory diagram showing an example of calculation of a temperature increase rate by the mold temperature controller 50 of the present embodiment; It is a schematic diagram which shows an example of transition of mold temperature. FIG. 3 is a schematic diagram showing an example of temperature rise characteristics of a mold; FIG. 4 is a schematic diagram showing the relationship between the temperature of the mold and the rate of change of the heating rate. FIG. 4 is an explanatory diagram showing an example of calculation of a temperature increase rate for threshold setting by the mold temperature controller of the present embodiment; FIG. 4 is a schematic diagram showing an example of a method of calculating a rate of change of a rate of temperature increase at a set temperature for threshold setting by the mold temperature controller of the present embodiment. FIG. 4 is a schematic diagram showing an example of transition of mold temperature during heating control by the mold temperature controller of the present embodiment. 4 is a flow chart showing an example of the procedure of heating control by the mold temperature controller of the present embodiment.

(First embodiment)
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described based on the drawings showing its embodiments. FIG. 1 is an explanatory diagram showing an example of the configuration of a mold temperature controller 50 as a temperature control device according to this embodiment. In this embodiment, the mold temperature controller 50 will be described as an example of the temperature control device, but the temperature control device is not limited to the mold temperature controller. The mold temperature controller 50 adjusts (controls) the temperature of the mold 200 as an object. Although the mold 200 will be described below as an example of the object, the object is not limited to the mold 200 .

A conduit 11 (medium feeding conduit) is connected to the inlet side of the mold 200 . Steam (heating medium) can be supplied to the mold 200 through a heating solenoid valve 21 as a heating valve interposed in the pipeline 11, and compressed air (compressor Air) can be supplied to the mold 200 , and cooling water (cooling medium) can be supplied to the mold 200 through a cooling electromagnetic valve 23 interposed in the pipeline 11 . In addition, below, the example which uses steam as a medium for a heating is demonstrated.

The pipeline 11 is branched into two systems on the way, and each of the branched pipelines 11 is connected to the inlet side of the mold 200 . A medium feeding valve 25 is interposed in each of the branched pipe lines 11 . A pressure sensor 32 for detecting the pressure of the steam is provided at a predetermined position of the pipeline 11 .

A pipeline 12 (return pipeline) is connected to the exit side of the mold 200 . A medium (for example, water or air) can be discharged through a drain electromagnetic valve 24 as a drain valve interposed in the pipeline 12 .

The pipeline 12 is branched into two systems on the way, and each of the branched pipelines 12 is connected to the outlet side of the mold 200 . A return medium valve 26 is interposed in each of the branched pipe lines 12 .

A temperature sensor 31 for detecting the temperature of the mold is provided at a predetermined location of the mold 200 .

The mold temperature controller 50 includes a control unit 51, a temperature acquisition unit 52, a temperature increase rate calculation unit 53, a threshold value setting unit 54, a storage unit 55, a pressure acquisition unit 56, a coefficient calculation unit 57, a required time calculation unit 58, and the like. Prepare.

The control unit 51 controls the opening/closing of the heating solenoid valve 21, the solenoid valve 22, the cooling solenoid valve 23, and the drain solenoid valve 24 (for example, opening/closing timing, opening time in the open state, closing time in the closed state, etc.).

FIG. 2 is a schematic diagram showing an example of temperature control of the mold 200 by the mold temperature controller 50 of this embodiment. In the figure, the horizontal axis indicates time, and the curve in the figure indicates the temperature of the mold 200. FIG. It should be noted that the temperature of the mold 200 in the drawing is schematically shown and may differ from the actual temperature.

When the temperature of the mold 200 is the heating start temperature (for example, 20° C.), the controller 51 starts heating control at time t1. Specifically, the heating solenoid valve 21 and the drain solenoid valve 24 are opened, the solenoid valve 22 and the cooling solenoid valve 23 are closed, and steam is introduced (supplied) into the mold 200 to heat the mold 200 . The drain solenoid valve 24 is opened to discharge a relatively large amount of drain at the beginning of heating.

At time t2, the controller 51 closes the drain electromagnetic valve 24. As shown in FIG. The reason why the drain electromagnetic valve 24 is closed is to raise (approach) the pressure in the medium flow path in the mold 200 and the pipe lines 11 and 12 to the pressure of steam, which is the heating medium. At this time, the temperature of the mold 200 also rises as the pressure rises, and the mold 200 is heated.

When the temperature of the mold 200 reaches a set temperature (for example, 120° C.), injection starts at time t3, and the mold 200 is filled with molten plastic.

At time t4, the control unit 51 closes the heating electromagnetic valve 21, opens the electromagnetic valve 22 and the drain electromagnetic valve 24, and supplies compressed air to the mold 200, thereby discharging steam remaining in the mold 200. .

At time t5, the controller 51 closes the solenoid valve 22 and opens the cooling solenoid valve 23 to start cooling control. Thereby, the temperature of the mold 200 is lowered.

The controller 51 closes the cooling solenoid valve 23 at time t6 and opens the solenoid valve 22 at time t7 to supply compressed air to the mold 200 . Thereby, water remaining in the mold 200 is discharged.

At time t8, the molded product is removed from the mold 200, ending the injection molding cycle. Further, the timing to take out the molded product is not limited to time t8 (for example, after compressed air is supplied to the mold 200 at time t7), but after the mold 200 is cooled to a predetermined temperature, that is, time t6. after closing the cooling solenoid valve 23 at , and before supplying the compressed air to the mold 200 at time t7. At this time, the supply of compressed air at time t7 ends the injection molding cycle.

A temperature acquisition unit 52 acquires the temperature of the mold 200 . The temperature acquisition unit 52 can acquire the temperature of the mold 200 by acquiring the signal output by the temperature sensor 31 provided inside the mold 200 .

The temperature rise rate calculator 53 obtains the A temperature increase rate of the mold 200 is calculated based on the temperature.

FIG. 3 is an explanatory diagram showing an example of calculation of the temperature increase rate by the mold temperature controller 50 of this embodiment. In the figure, the horizontal axis indicates time, and the vertical axis indicates the temperature of the mold 200 . Let T0 be the temperature of the mold 200 immediately before the start of heating. The temperature acquisition unit 52 acquires the temperature of the mold 200 at predetermined intervals Δt (for example, 1 second). As shown in FIG. 6, the temperature of the mold 200 at time t after the start of heating is T, and the temperature of the mold 200 at time (t−Δt) Δt before time t is T′. Then, the rate of temperature rise at time t can be obtained by [(TT')/Δt]. Note that the predetermined interval Δ is not limited to 1 second.

The control unit 51 controls opening and closing of the drain electromagnetic valve 24 based on the temperature increase rate calculated by the temperature increase rate calculation unit 53 . In the middle of the heating control for raising the temperature of the mold 200 to the set temperature, by providing control to open the drain electromagnetic valve 24 from closed based on the calculated temperature increase rate, the medium flow path in the mold 200 and the Drain accumulated in the pipeline 12 can be discharged, and a situation in which the temperature of the mold 200 reaches the set temperature is prevented from being delayed due to the accumulated drainage.

FIG. 4 is a schematic diagram showing an example of changes in mold temperature. In the figure, the horizontal axis indicates time, and the vertical axis indicates temperature. In the figure, the curve indicated by the solid line represents the transition of the temperature of the mold when the amount of drain accumulated in the medium flow path and the pipe line 12 in the mold 200 is small, and the curve indicated by the broken line indicates the amount of drain accumulated in the mold 200. Shows the transition of the mold temperature in the case of a large number. It should be noted that the transition of the temperature of the mold in the figure is schematically represented, and may differ from the actual transition of the temperature. As shown in FIG. 4, when there is a large amount of drainage accumulated in the medium flow path of the mold 200 and the pipe line 12, the temperature of the mold 200 does not reach the set temperature, or the time it takes to reach the set temperature is may be longer than if less condensate accumulated in the media flow path of the mold 200 and the conduit 12 . In addition, when a large amount of drainage accumulates in the medium flow path and the pipe line 12 of the mold 200, the temperature rise rate may be lower than when a small amount of drainage accumulates in the medium flow path and the pipe line 12 of the mold 200. I understand.

When the temperature increase rate calculated by the temperature increase rate calculation section 53 is smaller than the predetermined threshold value X, the control section 51 opens the drain electromagnetic valve 24 only for the required time. The predetermined threshold value X can be, for example, the rate of temperature increase at the set temperature of the mold 200 . When the temperature of the mold 200 is lower than the set temperature and no drainage accumulates in the medium flow path and the pipe line 12 in the mold 200, or when the amount of accumulated drainage is negligible, The rate of temperature rise never becomes equal to or less than the rate of temperature rise at the set temperature (that is, the predetermined threshold value X). Therefore, when the temperature increase rate calculated by the temperature increase rate calculator 53 is smaller than the predetermined threshold value X, it can be determined that the medium flow path and the pipe line 12 in the mold 200 are filled with drain. .

If the rate of temperature rise is smaller than the predetermined threshold value X, the drain solenoid valve 24 is opened for the required time. As a result, it is possible to discharge the drain accumulated in the medium flow path and the pipe line 12 in the mold 200, thereby preventing the delay in reaching the set temperature of the mold 200. Also, by opening the drain electromagnetic valve 24 only for the required time, it is possible to suppress the pressure drop of the steam.

Next, a method for setting the above threshold value X will be described.

FIG. 5 is a schematic diagram showing an example of temperature rise characteristics of the mold 200. As shown in FIG. In the figure, the horizontal axis indicates time, and the vertical axis indicates the mold temperature. In FIG. 5, the molds are divided into small, medium, and large molds, and the temperature rise characteristics of each mold are shown. Small size, medium size, and large size can be classified according to the size of the mold, for example. The temperature rise characteristics shown in FIG. 5 can be obtained, for example, by plotting actual measured values, or by calculating through simulation. It can be seen that when the mold is small, the time from the heating start temperature (eg, 20° C.) to reaching the set temperature (eg, 120° C.) is shorter than when the mold is large. In each curve in FIG. 5, the slope of the curve at any temperature represents the rate of temperature increase.

FIG. 6 is a schematic diagram showing the relationship between the temperature of the mold 200 and the change rate of the heating rate. In the figure, the horizontal axis indicates the temperature, and the vertical axis indicates the change rate of the heating rate. For example, if the heating start temperature T0 is 20.degree. C. and the set temperature Ts is 120.degree. C., the temperature rise (Ts-T0) at the set temperature of 120.degree.

The relationship between the temperature of the mold 200 and the rate of change in the heating rate is obtained by plotting the rate of change in the heating rate for each temperature rise of the die 200, and can be determined in advance by actual measurement values, simulation results, or the like. . In addition, the relationship between the temperature of the mold 200 and the change rate of the heating rate can be based on the assumption that there is no influence of the existence of the drain or it can be ignored. By connecting the plotted points plotting the rate of change in temperature rise rate for each temperature rise of the mold 200, the relationship between the temperature of the mold 200 and the rate of change in the rate of temperature rise is such that the rate of change decreases as the temperature rises. For example, it can be represented linearly or curvedly. Moreover, when the relationship is represented by a curved line, it can be approximated by one or a plurality of line segments.

In FIG. 6, Tv1 and Tv2 are the steam temperatures. For example, when the steam temperature is Tv1, the relationship between the temperature of the mold 200 and the rate of change in the rate of temperature increase can be represented by a solid line. When Tv2 (Tv2>Tv1), the relationship between the temperature of the mold 200 and the change rate of the temperature increase rate can be represented by a dashed line.

FIG. 7 is an explanatory diagram showing an example of calculation of the rate of temperature increase for setting the threshold value by the mold temperature controller 50 of the present embodiment. In the figure, the horizontal axis indicates time, the vertical axis indicates the temperature of the mold 200 , and the curve indicated by the solid line indicates the temperature rise characteristics of the mold 200 .

As shown in FIG. 7, the temperature of the mold 200 immediately before the start of heating is T0, and the temperature of the mold 200 after the time ta has elapsed after the start of heating is T1 (indicated by symbol A on the curve).

The rate of temperature increase (first rate of temperature increase) at temperature T1 can be expressed as [(T1-T0)/ta], which is the slope of the tangent line at point A of the curve. Note that the time ta or the temperature T1 does not have to be a fixed value, and can be set as appropriate. That is, the temperature T1 for calculating the first temperature increase rate can be set as appropriate.

The threshold value setting unit 54 sets the threshold value X based on the change rate at the set temperature and the first temperature increase rate in the relationship between the temperature of the mold 200 and the change rate of the temperature increase rate. The first temperature increase rate can be the temperature increase rate at the temperature T1 described above.

FIG. 8 is a schematic diagram showing an example of a method of calculating the change rate of the rate of temperature increase at the set temperature for threshold setting by the mold temperature controller 50 of the present embodiment. In the figure, the horizontal axis indicates the temperature, and the vertical axis indicates the change rate of the heating rate. Let T0 be the temperature of the mold 200 immediately before the start of heating, and let Rs be the change rate of the temperature rise rate when the temperature of the mold 200 is the set temperature Ts. Note that the relationship shown in FIG. 8 may be stored in the storage unit 55 in advance, or may be calculated.

As shown in FIG. 8, assuming that the rate of change in the temperature rise rate of the mold 200 can be represented by a straight line, the slope of the rate of change is , [−1/(Tv−T0)]. Further, the rate of change Rs of the heating rate at the set temperature Ts can be obtained by [1-{(Ts-T0)/(Tv-T0)}], and the heating rate at the set temperature Ts is , [Rs×(T1−T0)/ta]. (Code B in FIG. 7)

The threshold value setting unit 54 sets the temperature increase rate [Rs×(T1−T0)/ta] at the set temperature Ts as the predetermined threshold value X.

Accordingly, by calculating the temperature increase rate [(T1-T0)/ta] at the temperature T1 as the first temperature, the predetermined threshold value X of the temperature increase rate can be automatically set. It is possible to prevent a delay in the temperature of the mold 200 reaching the set temperature.

As described above, at time ta, the first heating rate is calculated and the threshold value X for the set temperature is set. After time ta, the temperature increase rate calculator 53 calculates the temperature increase rate based on the temperature of the mold 200 acquired at the predetermined interval Δt. The control unit 51 determines whether or not the temperature increase rate calculated by the temperature increase rate calculation unit 53 is smaller than a predetermined threshold X. Note that the temperature increase rate calculation period may be a predetermined interval Δt or an interval longer than the interval Δt.

FIG. 9 is a schematic diagram showing an example of transition of the temperature of the mold 200 during heating control by the mold temperature controller 50 of the present embodiment. Heating is started from the temperature of the mold 200 at T0, and the temperature of the mold 200 is T12 when the time t12 has elapsed. Since the valve 24 (discharge valve) is opened only for the required time, the drainage collected in the medium flow path and the pipe line 12 in the mold 200 is discharged from the drain electromagnetic valve 24 by steam. As a result, the drainage is removed, so that the temperature rise rate of the mold 200 increases, and it is possible to prevent the delay in reaching the set temperature. The operation of opening the drain electromagnetic valve 24 only for the required time to discharge the drain can be repeated if necessary by calculating the temperature rise rate of the mold 200 again.

Further, as described above, by calculating the first heating rate at the temperature T1 as the first temperature, the threshold value X can be automatically set, and the temperature of the mold 200 reaches the set temperature. It is possible to prevent the situation where the time to do is late.

Further, the threshold value setting unit 54 can set the threshold value X according to the steam temperature. When the temperature of the steam differs, as shown in FIG. 6, the slope of the rate of change in the relationship between the temperature of the mold 200 and the rate of temperature increase also differs. That is, the threshold X can be changed according to the slope of the rate of change, and the optimum threshold X can be set according to the steam temperature.

The pressure acquisition unit 56 acquires the pressure of steam. The pressure acquisition unit 56 can acquire the pressure of steam by, for example, acquiring a signal output by the pressure sensor 32 .

The coefficient calculator 57 calculates a weighting coefficient according to the difference between the saturation pressure based on the steam temperature and the pressure acquired by the pressure acquirer 56 . For example, the saturated pressure is calculated from the steam temperature and compared with the actual steam pressure. If the calculated saturated pressure is lower than the actual steam pressure, it is considered that the steam is moist and condensate tends to accumulate.

The threshold value setting unit 54 sets the threshold value X according to the coefficient (weighting coefficient) calculated by the coefficient calculation unit 57 . For example, when the calculated saturation pressure is lower than the actual steam pressure, the threshold is multiplied by a weighting factor that increases the threshold. By multiplying the threshold by a weighting factor that makes it smaller, it is possible to change the threshold X to a more appropriate one that also considers the state of the steam. The weighting coefficient may be calculated according to the difference between the calculated saturation pressure and the actual steam pressure, or may be a preset constant value. Note that the coefficient calculator 57 may not be provided when the weighting coefficient is constant.

The required time calculation unit 58 calculates the required time for opening the drain electromagnetic valve 24 according to the difference between the set temperature of the mold 200 and the temperature of the mold 200 when the temperature increase rate is calculated. For example, required time=[(preset temperature−temperature of mold 200 when heating rate is calculated)×coefficient].

The control unit 51 opens the drain electromagnetic valve 24 only for the required time calculated by the required time calculation unit 58 . The smaller the difference between the current mold temperature (the temperature of the mold 200 when the temperature rise rate is calculated) and the set temperature, the shorter the time required to open the drain solenoid valve 24 to reduce the pressure of the steam. prevent. By preventing the pressure from dropping, it is possible to prevent the temperature of the mold 200 from dropping.

FIG. 10 is a flow chart showing an example of the procedure of heating control by the mold temperature controller 50 of the present embodiment. In the following description, for the sake of convenience, the main body of processing is assumed to be the control unit 51 . The controller 51 starts heating the mold 200 (S11). When the heating is started, steam injection and heating shown in FIG. 2 are performed.

The control unit 51 acquires the first temperature in a state with little or no drain (S12), and calculates the rate of temperature increase at the first temperature (S13). The controller 51 sets the threshold value X at the set temperature based on the predetermined change rate of the temperature increase rate and the temperature increase rate at the first temperature (S14).

The control unit 51 acquires the temperature (S15), and calculates the rate of temperature increase at the acquired temperature (S16). The controller 51 determines whether or not the calculated temperature is equal to or higher than the threshold value X (for example, the rate of temperature increase at the set temperature) (S17).

If the rate of temperature rise is not equal to or greater than the threshold (NO in S17), the controller 51 opens the drain electromagnetic valve 24 (discharge valve) only for the required time (S18), and performs the process of step S19, which will be described later. When the temperature increase rate is equal to or higher than the threshold value X (YES in S17), the control unit 51 determines whether or not the temperature of the mold 200 has reached the set temperature (S19). (NO in S19), the process from step S15 onwards is continued.

If the set temperature has been reached (YES in S19), the control unit 51 terminates the process. After the heating control process shown in FIG. 10 is completed, a cooling process (not shown) is performed. After the cooling process, the process shown in FIG. 10 is performed in the next heating cycle. In the next heating cycle, if the molding conditions are the same, the processing of steps S12 to S14 can be omitted.

The mold temperature controller 50 of this embodiment can also be realized using a computer equipped with a CPU (processor), RAM, and the like. That is, as shown in FIG. 10, a computer program defining the procedure of each process is loaded into a RAM provided in the computer, and the computer program is executed by a CPU (processor), whereby the mold temperature controller can be operated on the computer. 50 heating control methods can be implemented.

As described above, according to the present embodiment, it is possible to specify the timing of drain discharge, and it is possible to discharge only the required amount of drain. It is possible to prevent the situation where the time of In addition, since the drain can be discharged, it is possible to prevent unnecessary drain heating, and it is possible to suppress unnecessary consumption of heat.

In each of the above-described embodiments, the threshold value is one value, but the threshold value may have a range of numerical values.

Although water can be used as the cooling medium in the above-described embodiments, oil can also be used instead of water.

The mold temperature controller 50 includes all or part of the heating solenoid valve 21, the solenoid valve 22, the cooling solenoid valve 23, and the drain solenoid valve 24, the medium supply valve 25, the medium return valve 26, and part of the pipelines 11 and 12. It may be a configuration comprising

In the above-described embodiment, the opening/closing control of the heating solenoid valve 21, the solenoid valve 22, the cooling solenoid valve 23, and the drain solenoid valve 24 is controlled by a single control unit, but is not limited to this. A different controller may control each electromagnetic valve.

In the above-described embodiment, the mold temperature controller was described as an example of the temperature control device, but the temperature control device is not limited to the mold temperature controller, and includes a device that controls heating using steam. The present embodiment can be applied to any device that does so.

A temperature control device according to an embodiment of the present invention is a temperature control device for controlling the temperature of an object having a medium flow path by flowing a medium through a conduit to obtain the temperature of the object. a temperature acquisition unit for controlling the opening and closing of a discharge valve for discharging the medium flowing out of the object; and a heating medium supplied to the object to heat it, and the temperature acquired by the temperature acquisition unit a temperature rise rate calculation unit that calculates a temperature rise rate of the object based on the temperature, and the control unit opens and closes the discharge valve based on the temperature rise rate calculated by the temperature rise rate calculation unit. Control.

A computer program according to the present embodiment is a computer program for causing a computer to control the temperature of an object having a medium flow path by causing a medium to flow through the conduit, the computer comprising: A process of acquiring the temperature of an object, a process of controlling the opening and closing of a discharge valve for discharging the medium flowing out of the object, and a heating medium supplied to the object to heat the object, and the obtained temperature and a process of controlling the opening and closing of the exhaust valve based on the calculated temperature rise rate.

A heating control method according to the present embodiment is a heating control method using a temperature control device for controlling the temperature of an object having a medium flow path by flowing a medium through a conduit, wherein the object A temperature acquisition unit acquires the temperature of the object, a control unit controls opening and closing of a discharge valve that discharges the medium flowing out of the object, and the object is heated by supplying the heating medium. A temperature increase rate calculation unit calculates a temperature increase rate of the object based on the temperature, and the control unit controls opening and closing of the discharge valve based on the calculated temperature increase rate.

The temperature acquisition unit acquires the temperature of the object. The object is, for example, a mold. By acquiring a signal output by a temperature sensor provided inside the mold, the temperature acquisition unit can acquire the temperature of the object (mold).

The control unit controls opening and closing of a heating valve for supplying the heating medium to the object and a discharge valve for discharging the medium flowing out from the object. Steam having a predetermined temperature and a predetermined pressure can be used as the heating medium. The medium that flows out from the object includes water (drain) in which the phase of the heating medium has changed, cooling water, and the like. The cooling medium is not limited to water, and may be oil, for example.

The temperature increase rate calculation unit calculates the temperature of the object based on the temperature acquired by the temperature acquisition unit in a state in which the object is heated by supplying the heating medium (for example, in a state in which the heating valve is opened and the discharge valve is closed). Calculate the temperature rise rate of the object. The temperature of the object can be obtained, for example, at each predetermined interval Δt. If the temperature of the object at time t after the start of heating is T, and the temperature of the object at time Δt before time t is T', the rate of temperature increase at time t is [( TT')/Δt].

The controller controls opening and closing of the discharge valve based on the temperature increase rate calculated by the temperature increase rate calculator. In the middle of the heating control for raising the temperature of the object to the set temperature, by providing control to open the discharge valve from closed based on the calculated temperature increase rate, the drainage accumulated in the medium flow path inside the object can be removed. Therefore, it is possible to prevent the accumulated drain from delaying the temperature of the object to reach the set temperature.

The temperature control device according to the present embodiment includes a threshold value setting unit that sets a predetermined threshold value, and the control unit controls the discharge temperature when the temperature increase rate calculated by the temperature increase rate calculation unit is smaller than the threshold value. Open the valve for the required time.

The threshold setting unit sets a predetermined threshold. The controller opens the discharge valve for the required time when the temperature increase rate calculated by the temperature increase rate calculator is smaller than a predetermined threshold. The predetermined threshold can be, for example, the rate of temperature increase when the object (for example, mold) is at the set temperature. When the temperature of the mold is lower than the set temperature, when there is no drainage accumulated in the medium flow path and the return medium pipe in the mold, or when the amount of accumulated drainage is negligible, The rate of temperature rise never becomes equal to or less than the rate of temperature rise at the set temperature (that is, the predetermined threshold value). Therefore, when the temperature increase rate calculated by the temperature increase rate calculation unit is smaller than a predetermined threshold value, it can be determined that drainage is accumulated in the medium flow path and the medium return line within the mold.

When the rate of temperature rise is smaller than a predetermined threshold, the drain valve can be opened for the required time to discharge the drain accumulated in the medium flow path and the return medium flow line in the object. It is possible to prevent a situation in which the temperature reaches the set temperature later. Further, by opening the discharge valve only for the required time, it is possible to suppress a decrease in the pressure of the heating medium.

In the temperature control device according to the present embodiment, the temperature increase rate calculation unit calculates a first temperature increase rate when the temperature of the object is a first temperature lower than the set temperature of the object, and The threshold value setting unit sets the threshold value based on the rate of change at the set temperature and the first rate of temperature increase in the relationship between the temperature of the object and the rate of change of the rate of temperature increase.

The temperature increase rate calculator calculates a first temperature increase rate when the temperature of the object is a first temperature lower than the set temperature. Assuming that the temperature of the object immediately before the start of heating is T0, and the first temperature of the object after the time ta has elapsed from the start of heating is T1, the first heating rate is [(T1-T0)/ta]. can be calculated.

The threshold setting unit sets the threshold based on the rate of change at the set temperature and the first rate of temperature increase in the relationship between the temperature of the object and the rate of change of the rate of temperature increase. The relationship between the temperature of the object and the change rate of the heating rate is obtained by plotting the rate of change of the heating rate for each temperature rise of the mold, and can be determined in advance by actual measurement values, simulation results, or the like. In addition, the relationship between the temperature of the object and the rate of change of the heating rate can be based on the assumption that there is no or negligible influence due to the presence of drain. By connecting the plotted points of the rate of change in temperature rise rate for each temperature rise of the mold, the relationship can be represented by a linear or curved line, for example, in which the rate of change decreases as the temperature rises.

Assuming that the rate of change in the rate of temperature increase can be represented by a straight line, the slope of the rate of change is [-1/(Tv-T0)] from the steam temperature Tv and the temperature T0 of the object immediately before the start of heating. Become. Let Ts be the set temperature of the object, and Rs be the rate of change in the heating rate at the set temperature Ts. The rate of temperature increase at the set temperature Ts is [Rs×(T1−T0)/ta].

Accordingly, by calculating the temperature increase rate at the first temperature T1, a predetermined threshold value of the temperature increase rate can be automatically set, and the time required for the temperature of the object to reach the set temperature is delayed. situation can be prevented.

In the temperature control device according to this embodiment, the threshold value setting unit sets the threshold value according to the temperature of the heating medium.

The threshold setting unit sets a threshold according to the temperature of the heating medium. If the temperature of the heating medium is different, the slope of the rate of change in the relationship between the temperature of the object and the rate of temperature increase will also be different. The threshold can be changed according to the slope of the rate of change, and the optimum threshold can be set according to the temperature of the heating medium.

The temperature control device according to the present embodiment includes a pressure acquisition unit that acquires the pressure of the heating medium, and a weighting coefficient that is determined according to the saturation pressure based on the temperature of the heating medium and the pressure acquired by the pressure acquisition unit. and a coefficient calculation unit for calculating, wherein the threshold setting unit sets the threshold according to the coefficient calculated by the coefficient calculation unit.

The pressure acquisition unit acquires the pressure of the heating medium. For example, the pressure of steam can be obtained by providing a pressure sensor in a pipeline that supplies steam to a mold, which is an object, and obtaining a signal output by the pressure sensor.

The coefficient calculation unit calculates a weighting coefficient according to the saturation pressure based on the temperature of the heating medium and the pressure acquired by the pressure acquisition unit. For example, the saturated pressure is calculated from the steam temperature and compared with the actual steam pressure. If the calculated saturated pressure is lower than the actual steam pressure, it is considered that the steam is moist and condensate tends to accumulate.

The threshold value setting unit sets the threshold value X according to the coefficient (weighting coefficient) calculated by the coefficient calculation unit. For example, when the calculated saturation pressure is lower than the actual steam pressure, the threshold is multiplied by a weighting factor that increases the threshold. By multiplying the threshold by a weighting factor that makes it smaller, it is possible to change the threshold X to a more appropriate one that also considers the state of the steam. The weighting coefficient may be calculated according to the difference between the calculated saturation pressure and the actual steam pressure, or may be a preset constant value.

The temperature control device according to the present embodiment provides a time required to open the discharge valve according to the difference between the set temperature of the object and the temperature of the object when the rate of temperature increase is calculated. A required time calculation unit is provided, and the control unit opens the discharge valve during the required time calculated by the required time calculation unit.

The required time calculation unit calculates the required time for opening the discharge valve according to the difference between the set temperature of the object and the temperature of the object when the rate of temperature increase is calculated. For example, required time=[(set temperature−current mold temperature)×coefficient].

The controller opens the discharge valve for the required time calculated by the required time calculator. The smaller the difference between the current mold temperature (the temperature of the object when the temperature rise rate is calculated) and the set temperature, the shorter the time required to open the discharge valve to prevent the steam pressure from dropping. By preventing a decrease in pressure, it is possible to prevent a decrease in temperature of the mold, thereby shortening the cycle time.

At least part of the above-described embodiments can be combined arbitrarily.

11, 12 pipeline 21 heating solenoid valve (heating valve)
22 solenoid valve 23 cooling solenoid valve 24 drain solenoid valve (discharge valve)
25 medium transfer valve 26 medium return valve 31 temperature sensor 32 pressure sensor 50 mold temperature controller (temperature control device)
51 control unit 52 temperature acquisition unit 53 temperature increase rate calculation unit 54 threshold setting unit 55 storage unit 56 pressure acquisition unit 57 coefficient calculation unit 58 required time calculation unit 200 mold (object)

Claims (5)

An object having a medium flow path connected to the inlet side with a medium supply line for supplying steam as a heating medium, discharging the outflowing medium, and connected to the outlet side with a line having a discharge valve interposed therebetween. A temperature control device for controlling the temperature of
a temperature acquisition unit that acquires the temperature of the object at predetermined intervals ;
a temperature increase rate calculation unit that calculates a temperature increase rate for each predetermined interval of the object based on the temperature acquired by the temperature acquisition unit while the object is heated by supplying steam;
a threshold setting unit that sets a predetermined threshold;
a control unit that controls opening and closing of the discharge valve based on the temperature increase rate calculated by the temperature increase rate calculation unit;
with
The temperature increase rate calculator,
calculating a first temperature increase rate when the temperature of the object is a first temperature lower than the set temperature of the object;
The threshold setting unit
a rate of change in temperature rise rate at the set temperature calculated from the relationship between the temperature of the object and the rate of change in temperature rise rate, which is predetermined according to the temperature of the heating medium; setting the temperature increase rate at the set temperature calculated based on the temperature increase rate as the threshold,
The control unit
A temperature control device that opens the discharge valve for a required time when the temperature increase rate calculated by the temperature increase rate calculator is smaller than the threshold value. a pressure acquisition unit that acquires the pressure of the heating medium;
a coefficient calculation unit that calculates a weighting coefficient according to the saturation pressure based on the temperature of the heating medium and the pressure acquired by the pressure acquisition unit;
with
The threshold setting unit
The temperature control device according to claim 1 , wherein the threshold value is set according to the coefficient calculated by the coefficient calculator. a required time calculation unit for calculating a required time for opening the discharge valve according to a difference between the set temperature of the object and the temperature of the object when the rate of temperature increase is calculated;
The control unit
3. The temperature control device according to claim 1, wherein the discharge valve is opened for the required time calculated by the required time calculation unit. An object having a medium flow path connected to the inlet side with a medium supply line for supplying steam as a heating medium, discharging the outflowing medium, and connected to the outlet side with a line having a discharge valve interposed therebetween. A computer program for causing a computer to control the temperature of
to the computer;
a process of acquiring the temperature of the object at predetermined intervals;
A process of calculating a temperature increase rate of the object at each predetermined interval based on the acquired temperature while the object is heated by supplying steam;
A process of calculating a first temperature increase rate when the temperature of the object is a first temperature lower than the set temperature of the object;
a rate of change in temperature rise rate at the set temperature calculated from the relationship between the temperature of the object and the rate of change in temperature rise rate, which is predetermined according to the temperature of the heating medium; a process of setting a temperature rise rate at the set temperature calculated based on a temperature rise rate as a threshold;
a process of opening the discharge valve for a required time if the rate of temperature rise calculated in the process of calculating the rate of temperature rise at each predetermined interval is smaller than the threshold ;
computer program that causes the An object having a medium flow path connected to the inlet side with a medium supply line for supplying steam as a heating medium, discharging the outflowing medium, and connected to the outlet side with a line having a discharge valve interposed therebetween. A heating control method by a temperature control device that controls the temperature of
A temperature acquisition unit acquires the temperature of the object at predetermined intervals,
A temperature increase rate calculation unit calculates a temperature increase rate for each predetermined interval of the object based on the obtained temperature while the object is heated by supplying steam,
The temperature rise rate calculation unit calculates a first temperature rise rate when the temperature of the object is a first temperature lower than the set temperature of the object,
a rate of change in temperature rise rate at the set temperature calculated from the relationship between the temperature of the object and the rate of change in temperature rise rate, which is predetermined according to the temperature of the heating medium; The threshold value setting unit sets the temperature increase rate at the set temperature calculated based on the temperature increase rate as a threshold,
Based on the calculated rate of temperature increase, a control unit that controls opening and closing of the discharge valve opens and closes the discharge valve for a required time when the rate of temperature increase calculated by the rate of temperature increase calculation unit is smaller than the threshold value. , the heating control method to open .

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