JP3262393B2 - Heat control method of intermediate molded product for blow molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the heating of a preform or a primary blow-molded product which is an intermediate product for blow molding.

[0002]

2. Description of the Related Art In a so-called two-stage blow molding machine, a preform injection-molded in a first stage is stored in advance, and the preform is supplied to a second stage, and a preform at normal temperature is supplied. After heating, it is blow molded into the final molded product.

The preform heating step greatly affects the quality of the blow-molded final container, and in order to obtain a final molded product having a constant quality, the preforms which are sequentially conveyed to the heating step are almost constant. It is necessary to heat to a temperature.

As a method for controlling the heating of the preform,
There is one disclosed in Japanese Patent Publication No. 4-22688. In order to carry out this method, as shown in FIG. 7, a heating furnace 1 divided into eight heating chambers 1a to 1h is configured so that a large number of preforms are transported, and its entrance and exit are provided. And a radiation thermometer 5 for detecting the temperature of the preform, respectively.
6 are arranged. Then, the above-mentioned method is applied to each heating chamber 1 according to the temperature of the preform immediately before being supplied to the heating furnace 1.
a control target of the power to be supplied to the far-infrared heater provided in each of a to 1h is set.
The correction is performed in accordance with the temperature of the preform that has been heated and carried out of the heating furnace 1 (see the above-mentioned Japanese Patent Publication No.
(See column lines 31-35).

[0005]

In carrying out the above method, two relatively expensive radiation thermometers 5, 6 for detecting the temperature of the preform must be provided at the entrance and exit of the heating furnace 1. Must. By providing two expensive radiation thermometers in this way, control becomes considerably complicated, but it is considered that heating temperature control with good response cannot be performed nonetheless.

The reason for this is that according to the above method, the heating chambers 8a to 8a are based on the data measured by the second radiation thermometer 6.
This is because all of 8h are controlled. Each heating room 8a ~
8h, there is a variation in each heater characteristic, so even if the same power is supplied to each heater, the temperature does not become the same, and the response of each heater also varies, so that the control to maintain the target preform temperature is performed. Is extremely difficult.

Further, according to the above method, the heating chambers 8a to 8
h, the temperature is detected by the second radiation thermometer 6 by, for example, a set of five pieces each receiving the heating action at the same time,
Feedback control is performed based on the result.
In this control, in order to prevent the preform from being heated at various set temperatures when being transported through the heating chambers 1a to 1h, each preform is heated until completion of the heating process. The heating levels of the heaters in the chambers 1a to 1h are unchanged (same as above, column 9, line 4 to column 12 of the above-mentioned publication).
line). Therefore, when the heating temperature for the preform newly supplied to the heating furnace 1 is determined, if it is different from the heating temperature for the preform already supplied to the heating furnace 1, the preform is placed in each heating chamber. The heating level of the heater must be changed each time the heater is carried in 1a to 1h, and the control is extremely complicated. Even if such complicated control is performed, the heater requires a long time to respond to the control, so that it is not possible to perform appropriate heating control.

Thus, all of the plurality of heating chambers 1a to 1a
If the heater temperature of h is controlled, appropriate heating control cannot be realized despite the complicated control.

The control is performed each time the measurement of the temperature of the five preforms is completed. However, the measurement data is not input until the temperature measurement of the next five preforms is completed.
This delays control.

Therefore, an object of the present invention is to sequentially detect the temperature of the intermediate molded product only at the exit side of the heating zone, and to perform feedback control of the heating zone temperature based on the average temperature of the plurality of intermediate molded products. It is an object of the present invention to provide a heating temperature control method for an intermediate molded product, which can perform heating control within a certain temperature range accurately and quickly while performing.

Another object of the present invention is to provide a method capable of realizing high-precision heating control even when a plurality of intermediate molded products are intermittently conveyed to a plurality of heating zones at the same time.

[0012]

According to a first aspect of the present invention, there is provided a heating unit in which a plurality of heating zones for heating the intermediate molded products are formed while a plurality of intermediate molded products are being transported,
A blow molding section for performing blow molding from the heated intermediate molded article to a hollow body, wherein N pieces of the intermediate molded articles are simultaneously heated in a heating zone immediately before the blow molded section, and the blow molding is performed one by one. With a blow molding machine carried out to the molding section,
In controlling the heating temperature of the intermediate molded product, (a)
Measuring the temperature of the intermediate molded product sequentially carried out from the heating zone located immediately before the blow molding section, and (b)
A set of n (2 ≦ n ≦ N) conveyed from the heating zone is taken as one set, and a set of intermediate molded products composed of n pieces is obtained by adding intermediate molded products sequentially conveyed from the heating zone. While updating, the average temperature of the intermediate molded product group of each set is sequentially calculated, and (c) the average temperature of the intermediate molded product group of each set is sequentially compared with a predetermined first set temperature range. And (3) when the average temperature is outside the first set temperature range, the heating level of a heater disposed in the heating zone immediately before the blow molding section is adjusted.

According to a second aspect of the present invention, one or a plurality of intermediate molded products carried out of the heating zone following the set of intermediate molded products that have fallen outside the first set temperature are (b) )
The method is characterized in that the intermediate molded product heated under the reset temperature condition is excluded from the calculation target of the step and is set as the calculation target of the step (b).

According to a third aspect of the present invention, when N pieces of intermediate molded articles are intermittently conveyed to a plurality of heating zones and then N pieces of blow molded articles are simultaneously blow-molded from the N pieces of intermediate molded articles, One set of the intermediate molded products is used, the average temperature of each set is compared with the first set temperature range, and the temperature of the heater in the heating zone immediately before the blow molding section is adjusted based on the comparison result. It is characterized in that at least one set of intermediate molded articles carried out of the heating zone following the set outside the temperature range is excluded from the target of the averaging calculation.

According to a fourth aspect of the present invention, the measured temperature of the intermediate molded product is compared with a second set temperature range, and the intermediate molded product determined to be outside the second set temperature range is blow molded. The intermediate molded product is carried out of the blow molding section without being subjected to the blow molding step when being carried into the section.

[0016]

According to the method of the present invention, the temperature of the intermediate molded product carried out from the heating zone immediately before the blow molding section is detected by the temperature detector based on the result of detection by the temperature detector. Among them, only the temperature of the heater disposed in the heating zone immediately before the blow molding section is feedback-controlled. As this feedback control, a set of n intermediate molded products is made, the average temperature of this set is compared with a set range, and the heating temperature of the heater is controlled based on the comparison result. Here, the temperature data of the intermediate molded product newly unloaded from the heating zone is added by excluding the oldest temperature data from the temperature data of the n intermediate molded products constituting the set, thereby forming one set. Has updated the group of intermediate molded products. Therefore, each time a new intermediate molded product is carried out from the heating zone, the heating condition of the heating zone can be monitored by comparing the setting range with the setting range. Can be adjusted.

After the heater temperature has been adjusted, the temperature data of one or a plurality of intermediate molded articles carried out of the heating zone following the set of intermediate molded articles having an average temperature outside the set temperature range is obtained. Is excluded from the averaging calculation, erroneous control can be prevented. When N pieces of intermediate molded articles are intermittently conveyed at the same time, the above-mentioned averaging operation, comparison with the first set temperature range, and heating of the final stage based on the comparison result are performed for each set of N pieces. Although the heater temperature of the zone is adjusted, the temperature averaging of at least one set of intermediate molded products unloaded from the heating zone following the set outside the set temperature range is not performed, resulting in incorrect temperature control. Can be prevented.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment to which the present invention is applied will be specifically described below with reference to the drawings.

The present embodiment is an apparatus in which the present invention is applied to a two-stage blow molding machine shown in FIG. In FIG. 1, a receiving station 12, a first heating station 14, a second heating station 16,
A blow molding station 18 and an eject station 20 are provided. The blow molding machine is supplied with the preform 10 via a chute 26, and the neck portion of the preform 10 is held by closing the coupling 24 provided at the tip of the support arm 22 at the receiving station 12. . The support arm 22 can expand and contract in the radial direction, and can accelerate and decelerate in the rotational conveyance direction. Due to the expansion and contraction and acceleration / deceleration functions of the support arm 22, in the first and second heating stations 14, 16, for example, six preforms 10 are provided.
Can be simultaneously performed for stretching suitable temperature in a state where are aligned in a line.

First and second heating stations 14 and 16
Have the same configuration, and the heating unit 30 shown in FIG.
The heating zones are respectively constituted by. This heating unit 30 is provided with a rod-shaped heater, for example, a quartz heater 32, which can simultaneously heat six preforms 10 at one position sandwiching the transfer position of the preform 10, and has a reflector 36 at the other position. are doing. Further, a temperature detector 38 configured by, for example, a radiation thermometer capable of detecting the temperature of the preform 10 is provided downstream of the heating unit 30 in the second heating station 16 in the transport direction. The temperature detector 38 is set at a position where light in the infrared region radiated from the quartz heater 32 in the heating unit 30 is not directly or indirectly incident.

The details of the heating unit 30 are shown in FIG. As shown in the figure, a plurality of quartz heaters 32 arranged in the heating unit 30 are arranged, for example, at equal intervals along the axial direction of the preform 10 so that the preforms 10 of various lengths can be heated. Has become. In the blow molding step after the heating step, a temperature distribution is provided in the axial direction of the preform 10 in order to secure a desired thickness distribution in the bottle to be blow molded. First, different temperature settings are performed in, for example, three zones along the axial direction of the preform 10. In the case of the present embodiment, for example, a first zone is formed by the quartz heater 32a located below the neck portion of the preform 10, and a second zone is formed by the quartz heaters 32b and 32c. A third zone is formed by the quartz heaters 32d to 32h. Since the lower part of the neck of the preform 10 needs to be heated to the highest temperature as shown in FIG.
It is preferable to dispose a quartz heater 32i at a position facing 2a.

In this embodiment, each of the first and second heating stations 14 and 16 has the heating unit 30 having the above-described configuration, and the heating control method is the first and second heating stations 14 and 16. Is different. In the first heating station 14, the set temperatures opposed to the above-described zones are manually set in advance, and fine adjustment is manually performed as needed. In the second heating station 16, the heaters 32 a to 32 i are set so that the temperature of the preform 10 falls within a certain set range based on a temperature detection result of a temperature detector 38 provided at a later stage in the unloading direction of the station 16. The heating temperature is controlled by feedback.

FIG. 3 shows a control system of the preform heating temperature in the second heating station 16. In the figure, a CPU 40 for controlling a heater is provided,
An operation board 42, an A / D converter 48, a D / A converter 50, a calculation unit 52, and an encoder 54 are connected to the CPU 40. The operation board 42 includes an operation input unit 44 and a display monitor 46.
, The initial set value of the set temperature corresponding to each zone in the heating unit 30 is input. The first and second set temperature ranges are input to the operation input unit 44, and each of the temperature ranges will be described later. The A / D converter 48 sends the temperature data of the preform 10 measured by the temperature detector 38 to the sensor controller 56.
Is entered via A temperature indicator 58 is connected to the sensor controller 56 so that the measured temperature of the preform 10 can be displayed. In the temperature detector 38, the temperature of the preform 10 is sampled a plurality of times, for example, 10 times. Each of the sampling data is transferred to the calculation unit 52 via the sensor controller 56, the A / D converter 48, and the CPU 40. The calculation unit 52 detects, for example, a temperature peak value as one data accurately reflecting the temperature of the preform 10 from the plurality of sampling data. The temperature detector 38 detects the temperature of the preform 10 sequentially carried out from the heating unit 30 of the second heating station 16. The detection timing is determined by the drive system of the support arm 22 that transports the preform 10. CPU 4 via the encoder 54
Input to 0.

The calculating section 52 sequentially stores the peak values of the temperatures of the respective preforms 10, and calculates the average value of the respective temperature peak values of the n preform groups. In this embodiment,
Although an averaging method is used as the averaging method, the present invention is not limited to this. Regarding the number n of the preforms 10 to be averaged, assuming that the number of the preforms 10 simultaneously heated by the heating unit 30 of the second heating station 16 is N, 2 ≦ n ≦ N. Is preferred. In the present embodiment, the simultaneous heating number N = 6 in the heating unit 30 is set as the number n to be averaged.

The arithmetic section 52 further determines whether or not the average temperature of the preform group is within a first set temperature range preset by the operation input section 44. In this embodiment, the first set temperature range is set to the center temperature value ± 1 ° C. Then, the arithmetic unit 52 obtains a comparison result between the average temperature of the n preforms 10 and the first set temperature range, and inputs this information to the CPU 40.

Under the control of the CPU 40, in order to control the heating temperature in each of the quartz heaters 32a to 32i,
The D / A converter 50 includes heater controllers 60a to
60g are respectively connected. The heater controller 60a controls the heating temperature of the quartz heaters 32a and 32i.
f controls the heating temperature of the quartz heaters 32b to 32f, and the heater controller 60g controls the heating of the quartz heaters 32b to 32f.
g, 32h. The heater controllers 60a to 60g control the power supplied to the quartz heaters 32a to 32h by a known phase control method, for example, to control the respective heating temperatures.

If the average temperature of the group of preforms 10 is within the first set temperature range, the CPU 40 maintains the previously set heating temperature based on the comparison result of the arithmetic unit 52. Each heater controller 60a ~
Control 60g. Then, only when the average temperature of the group of preforms 10 is outside the first set temperature range, information for adjusting the heating temperature is output to each of the heater controllers 60a to 60g. Here, the operation unit 52
Is the preform 1 on the transport front side of n preforms
The preform 10 newly removed from the heating unit 30 of the second heating station, excluding the temperature data of 0
By adding the temperature data of
The average temperature of each set of preform groups is sequentially calculated while updating one set of n preform groups. However, if a certain set of average temperatures is out of the first set temperature range by the arithmetic unit 52, the first set
The one or more preforms 10 carried out from the heating unit 30 following the set of preforms out of the set temperature range are excluded from the averaging calculation.

The operation unit 52 includes an operation input unit 4
4, the temperature of each preform 10 is compared with a second set temperature range that is set to a suitable blow molding temperature in advance. When the temperature of the preform 10 is out of the second set temperature range, based on a command from the CPU 40,
The preform 10 is carried out to the eject station 20 without performing the blow molding process at the blow molding station 18. This second set temperature range is a temperature range wider than the first set temperature range.

Next, the heating control of the preform 10 will be described in detail with reference to FIGS. FIG. 4 is an operation explanatory diagram for explaining a preform conveyance state, and FIG. 5 is a flowchart of heating control.

FIG. 1 to NO. The preform 10 of No. 6 is unloaded from the heating unit 30 of the second heating station 16 and is no. 7 to NO. 12 shows a state in which six preforms 10 are heated in the heating unit 30. NO. Preform 1 of 6
0 exists at a position facing the temperature detector, and the temperature is detected (step 100 in FIG. 5). And
NO. 1 to NO. The peak value of the temperature of each preform 10 of No. 5 has already been obtained by the calculation unit 52, and the respective values are stored. NO. When the temperature of the preform 10 is detected, the information is output to the calculation unit 52 via the CPU 40, and the peak value is obtained (step 101 in FIG. 5).

Next, the arithmetic section 52 determines whether or not this temperature peak value is within the second set temperature range (step 102 in FIG. 5). If step 102 is YES,
The preform 10 is subjected to blow molding (FIG. 5).
Step 103), if step 102 is NO,
The CPU 40 outputs a command to exclude the preform 10 from blow molding (step 10 in FIG. 5).
4). In this way, by blow-molding only the preform 10 within the second set temperature range, it is possible to blow-mold a bottle having a certain quality.

Thereafter, initially, the decision step 105 of FIG.
Is YES, and the temperature peak values of six consecutive preforms 10 have been measured.
6 is also YES. Therefore, after that, the average value of each peak value of the six preforms 10 is calculated (Step 107 in FIG. 5), and compared with the first set temperature range set in advance (Step 108 in FIG. 5).

If the temperature average values of the six preforms 10 No. 1 to No. 6 shown in FIG. 4A are within the first set temperature range, the CPU 40 has been set before that. Control is performed so as to maintain the heating temperature of the quartz heaters 32a to 32i (step 109 in FIG. 5).

Next, as shown in FIG. 4B, the preform 6 of No. 7 is transported to a position facing the temperature detector 38. Also in this case, steps 100 to 108 are executed similarly. At this time, in step 107, this No. 7 including the preform 6 of No. 7; The average temperature of the preform group of Nos. 2 to 7 is calculated and obtained.

Here, No. 2-No. If the average temperature of the six preforms 10 exceeds the upper limit of the set temperature range, for example (NO in step 108), the CPU 40 transmits the heat controller 60 via the D / A converter 50.
For a to 60 g, a control command for lowering the temperature uniformly by a certain value from the currently set heating temperature is output (step 110 in FIG. 5). Based on a command from the CPU 40, each of the heat controllers 60a to 60g performs a control to uniformly lower the electric power supplied to each of the quartz heaters 32a to 32i by a phase control. The responsiveness of the quartz heaters 32a to 32i reaches 90%, for example, about 2 seconds after the set temperature is changed.

If step 108 is NO, C
The PU 40 is subsequently transported to Nos. 2 to 7 having an average temperature outside the first set temperature range, for example, 2
A command is output to exclude the preforms 10 of Nos. 8 and 9 from being subjected to the averaging operation in step 107 (step 111 in FIG. 5).

In the step of FIG. 2-No. Similarly, after it was found that the average temperature of the six preforms 10 of No. 7 was out of the first set temperature range, No. 7 was similarly used. 8
Subsequent preforms 10 are sequentially conveyed to a position facing the temperature detector 38. In the present embodiment, in the same manner, the temperature detector 38 outputs No. The temperature of the preform 10 after 8 is detected, and the steps 100 to 105 are executed. However, since the determination at step 105 is NO,
No. 8 and No. The peak temperature values of the two preforms 9 are not subjected to the averaging operation. Since these two preforms 10 have not been heated at the reset heating temperature for a sufficient time, if these are subjected to averaging calculation, erroneous control will be performed at the next temperature control. It is. In this embodiment, two preforms 10
Is excluded from the averaging operation. One of the reasons is that it takes about 2 seconds for each of the quartz heaters 32a to 32i to respond to the reset heating temperature. Also,
Another reason is that there is a preform 10 unloaded from the heating unit 30 of the second heating station 16 without being heated for a sufficient time after the response of the heater.
Thus, in the present embodiment, No. 8 and No. By excluding the two preforms 9 from the averaging operation,
Only the preform 10 that has been heated in the heating state in which the level has reliably changed can be subjected to the subsequent heating temperature control.

FIG. 15 preforms 10
Indicates a state in which the sheet is conveyed to a position facing the temperature detector 38. At this time, the temperatures of the five preforms No. 10 to No. 14 have already been detected, but only steps 100 to 106 are executed for each of the preforms 10. Step 107
Is not performed. Then, the judgment step 106 is YES for the No. 15 preform 10 for the first time.
Therefore, the six preforms No. 10 to No. 15
Is calculated. Then, similarly, based on whether the average temperature is within or outside the first set temperature range, each heat controller 6
The heating temperature control of 0a to 60i is performed.

As described above, according to the present embodiment, the heating temperature of the heater in the first heating station 14 is described above only in the second heating station 16 while fixing the temperature by manual control in advance. By performing the feedback control of the heating temperature, a bottle having a constant quality could be formed with high stability in the blow molding station 18 which is the next step. Further, after the average temperature of one group of six preforms 10 is out of the set temperature range, the two preforms 10 continuously conveyed to a position facing the temperature detector 38 are subjected to an averaging calculation. By excluding the target, erroneous feedback control can be prevented.

Next, a preferred heating control method in an oven blow molding machine for performing blow molding from a primary blow molded product to a secondary blow molded product which is a heat resistant container will be specifically described with reference to the drawings.

FIG. 6 is a plan view of an oven blow molding machine, and a rotating disk 80 for rotatingly transporting a primary blow molded product 70.
, A loading station 82, a heating furnace 84,
A secondary blow molding station 86 and an ejection station 88 are provided. At the loading station 82,
The supply device 82a is provided at the take-out station 88 with a take-out device 88a. The take-out device 88a supplies the primary blow-molded product 70 to the rotary conveyance path of the rotary disk 80, and takes out the product after the secondary blow-molding. The heating furnace 84 is divided into five heating zones 84a to 84e as shown in FIG. The primary blow molded product 70 is
4a to 84e, the primary blow molded product 70 is shrunk to a predetermined axial length by receiving a blow of hot air heated by heaters provided independently for each zone in the process of being sequentially conveyed. Let me. The secondary blow molding station 86 is provided with a mold clamping device 86a,
The secondary blow-molded product as a heat-resistant container is formed by subjecting the contracted primary blow-molded product 70 to biaxial stretching blow molding.

In the case of the above-mentioned oven blow molding machine, the heaters of the four heating zones 84a to 84d are previously adjusted so as to generate hot air of a predetermined temperature by manual operation. And the secondary blow molding station 86
The heating control of the heater provided in the heating zone 84e located immediately before is controlled by the feedback control based on the measurement data detected by the temperature detector 38 provided downstream of the heating zone 84e in the transport direction. .

In this embodiment, each heating zone 84
a to 84e simultaneously heated primary blow-molded article 70
Is four. The four primary blow-molded articles 70 are simultaneously rotated and conveyed by the intermittent rotation of the turntable 22, and are stopped for a predetermined time in each of the heating zones 84a to 84e to receive a heating action.

The temperature detector 38 is connected to the fifth heating zone 8
When the four primary blow molded articles 70 are intermittently rotated and conveyed from 4e to the secondary blow molding station 86, the temperatures of the four primary blow molded articles 70 are sequentially measured according to the order of conveyance. Alternatively, the temperatures of the four primary blow molded articles may be measured simultaneously by the four temperature detectors 38. The feedback control of the heating temperature based on the measurement data from the temperature detector 38 can use the temperature control system shown in FIG. That is, 4 via the CPU 40
The sampling value of each temperature data of the primary blow-molded products 70 is input, the peak value is obtained, and then the average temperature value of the four temporary blow-molded products 70 is calculated. Then, the average temperature of the four primary blow-molded products 70 is compared with a first set temperature range that is set in advance, and based on the comparison result, the CPU 40 controls the power to the heater disposed in the heating zone 84e. Through the heater controller. Note that the first set temperature range for controlling the heating level of the heating zone 84e does not need to be as strict as the set temperature range in the two-stage type blow molding machine described above. Even if the first set temperature range is wider than the first set temperature range of the two-stage type,
It is possible to obtain a secondary blow-molded product having a constant quality and good stability.

In this embodiment, the averaging operation is performed for each of the four primary blow-molded articles 70 conveyed simultaneously, and one primary blow-molded article 70 is subjected to the averaging operation a plurality of times. This embodiment is different from the above embodiment in that it is not subject to the above. Also,
If the average temperature of the four primary blow molded articles 70 conveyed simultaneously falls outside the set temperature range, the four position blow molded articles 70 conveyed simultaneously next time should not be subjected to the averaging calculation. Thus, erroneous feedback control can be prevented. In addition, as a method of not subjecting a primary blow molded product outside the second set temperature range to blow molding,
If one of the four falls outside the second set temperature range,
Even if all four are not blow-molded,
A method in which only individual pieces are not subjected to blow molding may be used.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, as shown in FIG. 3, the temperature detector 38 detects the temperature of each zone in correspondence with the provision of the quartz heaters 32 a to 32 i divided into three zones along the axial direction of the preform 10. It may be configured as follows. It is also possible to provide a set temperature range corresponding to each zone in advance, and to independently perform feedback control of the heating temperature for each zone based on a comparison result with the set temperature range.

[0047]

As described above, according to the present invention,
The average value of the temperature of one set of intermediate molded products, which is carried out from the last heating zone on the conveying path, is calculated, and one set of intermediate products is newly carried out from the last heating zone. While updating the group of intermediate molded articles constituting the above, whether or not the average temperature value of each set is within the first set temperature range is sequentially compared, and if the average temperature value is out of the range, the heater temperature of the final stage heating zone is determined. By controlling the amount of heating, it is possible to perform heating control for stably forming a final molded product having a constant quality. In addition, erroneous control can be performed by not subjecting one or a plurality of molded articles carried out of the heating unit following the plurality of intermediate molded articles having an average value outside the first set temperature range to the averaging calculation. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a plan view of one embodiment of a blow molding machine to which the present invention is applied.

FIG. 2 is a schematic explanatory view showing a heating zone of the heating station shown in FIG.

FIG. 3 is a block diagram showing a heating temperature control system of a heater arranged in a second heating station shown in FIG.

FIG. 4 is an explanatory diagram of the operation of the embodiment apparatus shown in FIG. 1;

FIG. 5 is a flowchart showing an operation of the temperature control system shown in FIG. 3;

FIG. 6 is a schematic plan view showing an oven blow molding machine.

FIG. 7 is a schematic explanatory view showing an arrangement of a conventional temperature detector for heating control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Preform 14, 16 Heating station 18 Blow molding station 30 Heating unit 32a-32i Quartz heater 38 Temperature detector 40 CPU 52 Operation part 54 Encoder 60a-60g Heater controller 70 Primary blow molded article 84 Heating furnace 84a-84e Heating zone 86 Secondary blow molding station

Claims (4)

(57) [Claims] 1. A heating section having a plurality of heating zones formed therein for sequentially carrying in and heating the intermediate molded articles while a plurality of intermediate molded articles are being transported, and a hollow section formed from the heated intermediate molded articles. Having a blow molding part for blow molding to the body,
In the heating zone immediately before the blow molding unit, the N intermediate molded products are heated, and the heating temperature of the intermediate molded products is controlled by a blow molding machine which is carried out one by one to the blow molding unit. (A) measuring the temperature of the intermediate molded product sequentially carried out from the heating zone located immediately before the blow molding portion, and (b) n (2 ≦ n ≦ N) carried out from the heating zone. The average temperature of each set of intermediate molded products is updated while updating a set of intermediate molded products composed of n pieces by adding the intermediate molded products sequentially taken out from the heating zone as one set. (C) sequentially compare the average temperature of each set of intermediate molded products with a predetermined first set temperature range; and (d) this average temperature is outside the first set temperature range. At the time, placed in the heating zone immediately before the blow molding section Heating control method of the intermediate molded article for blow molding acceleration adjusting the heat level of the heater, characterized in that the. 2. The method according to claim 1, wherein one or a plurality of intermediate molded products unloaded from the heating zone following the set of intermediate molded products outside the first set temperature range. b) excluded from the calculation target of the process,
A method for controlling the heating of an intermediate molded product for blow molding, wherein the intermediate molded product after being heated under the reset temperature condition is subjected to the calculation in the step (b). 3. A heating section in which a plurality of heating zones for simultaneously heating N pieces of the intermediate molded products are formed while the intermediate molded products are intermittently transported N pieces at a time. When controlling the heating temperature of the intermediate molded article by a blow molding machine having a blow molding section for performing blow molding from the intermediate molded article into N hollow bodies, (a) the blow molding section is located immediately before the blow molded section. Measuring the temperature of the N intermediate molded products simultaneously discharged from the heating zone, and (b) setting a set of the N molded products simultaneously discharged from the heating zone, and (C) sequentially comparing the average temperature of each set of intermediate molded products with a predetermined first set temperature range;
(D) when the average temperature is outside the first set temperature range, adjust the heating level of a heater disposed in the heating zone immediately before the blow molding section, and (e) adjust the heating level of the heater.
And at least one set of intermediate molded products carried out of the heating zone following the set of intermediate molded products outside the set temperature range is excluded from the calculation target in the step (b), and the reset temperature is set. A method for controlling the heating of an intermediate molded product for blow molding, wherein the set of intermediate molded products heated under the conditions is subjected to the calculation in the step (b). 4. The intermediate molding device according to claim 1, wherein the measured temperature of the intermediate molded product is compared with a second set temperature range, and the measured temperature is determined to be outside the second set temperature range. A method for controlling the heating of an intermediate molded product for blow molding, wherein the product is carried out of the blow molded portion without going through a blow molding step when the product is carried into the blow molded portion.