JP7256798B2 - Blow nozzle for use in blow molding equipment, method of blow molding using said blow nozzle and stretched rod - Google Patents

Description

The present invention relates to a blow nozzle with a stretch rod for use in at least a liquid blow molding apparatus, a blow molding method using the blow nozzle, and a stretch rod for use in the blow nozzle.

Blow nozzles are known in which a stretch rod stretches the preform when molding the preform with at least a liquid.

However, liquid remaining in the blow nozzle can fall onto the heated preform in the next cycle before the liquid is injected, even when the stretch rod is retracted. In such a case, the temperature of the location where the liquid has fallen is lowered, which may cause problems in forming the container. Also, even if the liquid that has dropped from the blow nozzle adheres to the conveying part, it will cause similar problems in container molding when the liquid drops from the conveying part onto the preform.

The blow nozzle described in US Pat. a sealing rod (50) that moves to and from a second position that allows liquid to inject. However, in the blow nozzle described in Patent Literature 1, the extensible rod for molding and the sealing rod are separate members, so the mechanism is complicated.

Japanese Patent No. 6157353

The present invention has been made in view of the above facts, and is a blow nozzle that stretches a preform with a stretching rod, and prevents residual liquid in the blow nozzle from dropping onto the preform or parts of the blow molding apparatus with a simple structure. Its purpose is to

In order to solve the above problems, the blow nozzle of the present invention includes a nozzle body and an extension rod inserted through the nozzle body, the nozzle body being adaptable to the mouth of the preform. a nozzle tip provided at the tip of the nozzle, an injection port formed at the nozzle tip, a port for introducing fluid containing at least liquid into the nozzle body, and the port and the injection port are communicated with each other a fluid passageway formed in the nozzle body such that the stretch rod passes through an axially extending section of the fluid passageway to the jet opening and passes through the jet to stretch the preform. The extension rod is axially reciprocable with respect to the nozzle body between a position in which the extension rod is more extended from the mouth and a position in which the extension rod is retracted, and the extension rod includes a closure, the closure comprising: The jet nozzle is closed when the stretching rod is in the retracted position, and the closing of the jet nozzle is released when the stretching rod moves to the protruding position. be.

The preferred extension rod comprises a straight rod body inserted through the blow nozzle and the closure is a large diameter portion of the rod body that fits against the inner peripheral wall of the nozzle body defining the fluid passageway. . Preferably, the large-diameter portion has a seal portion on the outer peripheral portion that engages with the inner peripheral wall.

Preferably, the fluid is a mixture of liquid and air, and the mixture can be introduced through the port. Alternatively, said ports comprise a first port through which liquid is introduced and a second port through which air is introduced, said fluid passage containing a fluid which is a mixture of the introduced liquid and air. You can let it flow.

Another aspect of the present invention is a method of blow molding a preform using the blow nozzle configured as described above, wherein the temperature-controlled preform is set in a blow cavity mold, and the mouth portion of the preform is by fitting the nozzle tip of the blow nozzle with the closing part closed to the nozzle tip of the blow nozzle, moving the stretch rod toward the bottom of the blow cavity mold and introducing fluid into the nozzle body, thereby moving the The preform is stretched by a stretching rod and is stretched by the fluid jetted from the opened injection port. After the stretched preform is completely molded by the blow cavity mold, the stretching rod is It is configured with each step of moving away from the bottom of the blow cavity mold to close the injection port. Preferably, the method further comprises the step of pulling the blow nozzle away from the blow cavity mold and the finished product while the nozzle is closed by the step of closing the nozzle. More preferably, the step of separating the blow nozzle from the step of setting the preform in the blow cavity mold is repeatedly performed for the preform of the next cycle.

For example, the blow cavity mold comprises at least two blow mold halves, and the step of setting the preform in the blow cavity mold comprises the step of closing the blow mold halves.

In the step of fitting the tip of the blow nozzle, the tip of the stretch rod is in contact with the bottom of the preform when the closure is closed or before the closure is released.

A stretch rod according to still another aspect of the present invention is provided for a blow nozzle for blow-molding a preform by injecting a fluid containing at least a liquid, and the blow rod is inserted through the blow nozzle. a rod body linearly formed for reciprocal movement relative to the nozzle; and a closure formed in the rod body, the closure allowing the extension rod to retract into the blow nozzle. and the closing portion that closes the injection port of the blow nozzle at a predetermined position.

A preferred closing portion is a large diameter portion formed to fit the inner peripheral wall of the nozzle body near the injection port.

FIG. 1 is a schematic diagram of a blow nozzle according to one embodiment of the present invention, showing a state in which the injection port of the blow nozzle is closed. FIG. 2 is a schematic diagram of a blow nozzle according to an embodiment of the present invention, showing a state in which the injection port of the blow nozzle is open. FIG. 3 is a schematic diagram showing a pre-process of a preform blow molding process using a blow nozzle according to an embodiment of the present invention, in which (A) is a preform carrying-in process, and (B) is a , respectively showing the closing of the blow split mold. FIG. 4 is a schematic diagram showing the process of blow molding a preform using a blow nozzle according to an embodiment of the present invention, (A) before blow molding, (B) during blow molding, (C ) indicates the state when blow molding is completed. FIG. 5 is a schematic diagram showing the post-process of the process shown in FIG. 4, wherein (A) is when the stretching rod is pulled up, (B) is when the injection port is closed, and (C) is when the blow nozzle is pulled apart. , respectively. FIG. 6 is a schematic diagram showing one configuration example of a fluid supply unit that supplies pressurized fluid to the blow nozzle according to the present embodiment. FIG. 7 is a perspective view of a rotary transfer type blow molding machine incorporating a blow molding device that performs blow molding using a blow nozzle according to one embodiment of the present invention. FIG. 8 is a flow chart showing the process of blow molding a preform using a blow nozzle according to one embodiment of the present invention. FIG. 9 is a flow chart showing more detailed steps of longitudinal and transverse stretching of the preform in the flow chart of FIG. Fig. 10 is a schematic diagram showing a stretch rod according to a second alternative embodiment of the invention;

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 shows a blow nozzle 1 according to a first embodiment of the invention. The blow nozzle 1 is for use in a blow molding apparatus for blow molding preforms, as will be described later. 2 and a stretch rod 3 attached to it. The extension rod 3 is attached to the nozzle body 2 so as to be axially reciprocatingly movable relative to the nozzle body 2 as indicated by an arrow A by a driving means (motor or the like) not shown.

The nozzle body 2 includes a nozzle tip 4 provided at the tip of the nozzle body 2 so as to be compatible with the mouth of the preform, an injection port 5 formed in the nozzle tip 4, and a fluid containing at least liquid in the nozzle body. 2, and a fluid passage 7 formed in the nozzle body 2 so as to communicate between the port 6 and the injection port 5. - 特許庁

The extension rod 3 comprises a straight rod body and a closure 10 formed near the tip 9 of the rod body. The closure 10 is a large diameter portion formed to fit the inner peripheral wall 12 near the injection port 5 and is configured to have a larger radius than the rod body. As shown, the straight rod body of the extension rod 3 slidably and liquid-tightly penetrates the through hole 11 of the nozzle body 2, and further passes through a section of the fluid passage 7 leading to the injection port 5. are doing. 1, in which the closure 10 is in the fluid passage 7, the outer peripheral wall of the closure 10 is in slidable and liquid-tight engagement with the inner peripheral wall 12. As shown in FIG. That is, the extension rod 3 is inserted through the nozzle body 2 so as to be reciprocally movable in the axial direction with respect to the nozzle body 2 as indicated by the arrow A, and the extension rod 3 relative to the nozzle body 2 shown in FIG. In the position, the closure 10 closes the orifice 5 in a liquid-tight manner.

In order to allow the outer peripheral wall of the closing part 10 to slidably and liquid-tightly engage with the inner peripheral wall 12, the outer peripheral wall of the closing part 10 is formed with, for example, a groove along the circumferential direction. A sealing member such as an O-ring may be arranged in the groove. Similarly, since the straight rod body of the extension rod 3 penetrates the through hole 11 of the nozzle body 2 in a slidable and liquid-tight manner, the inner peripheral wall of the through hole 11 is provided with a groove along the circumferential direction, for example. may be formed, and a sealing member such as an O-ring may be arranged in the groove.

As shown in FIG. 2, when the extension rod 3 is moved from the predetermined position shown in FIG. , the injection port 5 is opened. Here, even if the small-diameter rod body of the extension rod 3 exists in the fluid passage 7, the fluid passes between the rod body and the inner peripheral wall 7 of the nozzle body 2 defining one section of the fluid passage 7. A possible gap 8 is formed.

A fluid supply unit 13 that supplies pressurized fluid to the blow nozzle 1 is connected to the port 6 via a supply path 14 . Therefore, in the state shown in FIG. 2, when fluid is supplied from the fluid supply portion 13 through the supply passage 14 to the port 6, the supplied fluid passes through the gap 8 of the fluid passage 7 and exits the injection port 5. As shown by arrow B, it is jetted to the outside. As will be described later, the fluid supply unit 13 includes an on-off valve WV1, and depending on the opening/closing operation of the on-off valve WV1, whether or not the pressurized fluid is supplied to the blow nozzle 1, as well as the injection in the open state shown in FIG. Whether or not the fluid is jetted from the mouth 5 is controlled.

In addition, in order to improve the molding conditions and shorten the molding cycle, it is possible to prevent the fluid from entering the gap 8 of the nozzle body 2 before the extension rod 3 moves toward the bottom die (when the ejection port 5 is in the closed state). may be stored in advance, and an operation may be performed such that the fluid is introduced into the preform at the same time as the stretching rod 3 is moved (at the same time as the ejection port 5 is opened). That is, the opening/closing portion 10 of the extension rod 3 may be used instead of the fluid opening/closing valve.

The fluid used for blow molding in this embodiment is a liquid or a mixture of liquid and gas. An example of a preferred liquid is water and an example of a preferred gas is air (compressed air). When a mixture of liquid and gas is used, the fluid supply section 13 is supplied with the liquid and the gas, and the fluid supply section 13 introduces the mixture of liquid and gas into the port 6 .

FIG. 6 shows one configuration example of the fluid supply section 13 that introduces the pressurized fluid, which is a mixture of water and compressed air, into the blow nozzle 1 . The fluid supply unit 13 includes a water supply source 60, a water supply circuit 62 for sending out the water supplied from the water supply source 60, a storage unit 64 (hose or tank, etc.) for storing a predetermined amount of water from the water supply circuit 62, A high-pressure gas source 66 such as a compressor, an air supply circuit 68 for delivering compressed air supplied from the high-pressure gas source 66 to the reservoir 64, and an air generator 70 for causing the high-pressure gas source 66 to generate the compressed air. , an exhaust circuit 72 for exhausting excess air from the reservoir 64 and the like, and a vacuum pump 74 and a vacuum suction circuit 76 for vacuum-sucking the inside of the blow nozzle 1 through the supply path 14. there is

Furthermore, the fluid supply unit 13 controls the supply of the pressurized fluid sent from the storage unit 64 to the supply path 14, and the supply of compressed air from the air supply circuit 68 to the storage unit 64. a water supply valve WV3 for controlling the supply of water from the water supply circuit 62 to the reservoir 64; an air vent valve WV4 for controlling exhaust of excess air remaining in the reservoir 64 and the like; and a vacuum suction valve WV5 for controlling the vacuum suction of the blow nozzle 1 via the suction circuit 76 .

Alternatively, the fluid supply 13 may supply the liquid and the gas separately to the blow nozzle 1 . In this case, the port 6 has a first port into which liquid is introduced and a second port into which air is introduced. , a fluid that is a mixture of liquid and air flows through the fluid passage 7 .

A preform to be blow-molded by the blow nozzle 1 is molded through, for example, four main steps in a rotary transfer type blow molding machine 200 shown in FIG. 7, and taken out as a molded finished product. These four steps are an injection molding step, a temperature control step, a blow molding step, and a take-out step. The rotary conveying blow molding machine 200 includes an injection molding station 202, a temperature control station 204, a blow molding station 206, and a take-out station 208, each of which executes the four processes described above in each of the four divided areas of the 360° conveying area. is provided.

The injection molding station 202 molds a plurality of preforms 50 by injecting a resin material (for example, resin made of PET, PE, or PP) from an injection device (not shown) into an injection mold 210 (injection step).

A plurality of injection-molded preforms 50 are conveyed to the temperature control station 204 by conveying means (rotary disk or the like) (not shown) while their mouths are held by the conveying plate 212 . In the temperature control station 204, the temperature is adjusted so that the preform 50 reaches an appropriate molding temperature before blow molding (temperature control step). This temperature control step is performed, for example, by placing the preform 50 in the heating pot 214 and inserting the temperature control core 216 inside the preform 50 .

The temperature-controlled preform 50 is transported to the blow molding station 206 by transport means (not shown). At the blow molding station 206, the blow cavity mold 100 is loaded with the preform 50, and the above-described fluid is introduced into the preform 50 using the blow nozzle 1 according to the present embodiment, as will be described later in detail. The reform 50 is blow molded into a finished molded product 52 .

The blow-molded finished product 52 is transported to the unloading station 208 by transport means (not shown). At the take-out station 208, the molded product 52 is taken out from the rotary transfer blow molding machine 200 by take-out means (not shown) (take-out step).

Next, the flow of preform blow molding using the blow nozzle 1 according to the present embodiment will be described according to the flow chart of FIG. 8 while referring to FIGS. 3 to 5 .

As shown in FIG. 8, first, a temperature conditioned preform 50 is loaded into the blow molding station (206 in FIG. 7) (step 300). As shown in FIG. 3A, preform 50 is placed between blow molds 100A and 100B spaced apart from each other. At this time, the blow nozzle 1 is arranged above the preform 50 with the injection port 5 closed by the closing portion 10 .

Next, the blow split molds 100A and 100B are closed (step 301). This completes the setting of the preform 50 to the blow cavity mold 100 . As shown in FIG. 3B, the closed blow split molds are united to form a blow cavity mold 100, and an upper opening 101 of the blow cavity mold 100 is fitted with a mouth portion 55 of the preform 50. be worn. The inner surface of blow cavity mold 100 forms molding surface 102 .

Next, the blow nozzle 1 is lowered, and the nozzle tip 4 of the blow nozzle 1 is fitted to the mouth portion 55 of the preform, specifically, to the inner wall surface of the mouth portion 55 (step 302). The blow split molds 100A and 100B may be closed after fitting the nozzle tip 4 of the blow nozzle 1 to the mouth 55 of the preform 50. FIG.

FIG. 4A shows the state when steps 300 and 302 are executed. The state of FIG. 4A is a state in which the preparation for blow molding is completed.

Blow molding is then performed by stretching the preform longitudinally and transversely (step 304 in FIG. 8). As shown in FIG. 4(B), in step 304, the extension rod 3 is lowered to release the closure of the injection port 5 by the closing part 5, and pressurized fluid including liquid and gas is introduced into the port 6. . Thereby, the preform 51 being molded is stretched mainly in the longitudinal axis by the stretching rod 3 and in the transverse axis by the pressurized fluid.

After certain conditions are met, the movement of the stretch rod 3 is stopped, the introduction of fluid to the port 6 is stopped and the blow molding is completed (step 306 in FIG. 8). As shown in FIG. 4(C), a molded product 52 (hollow container) is finally molded by the molding surface 102 .

After blow molding is completed, the stretch rod 3 is moved away from the bottom of the blow cavity mold 100 (step 308 in FIG. 8). The state of step 308 is shown in FIG. 5(A).

When the moving extension rod 3 reaches a predetermined position, the closing portion 10 liquid-tightly closes the inner peripheral wall 12 of the nozzle body 2 near the injection port 5 (step 310 in FIG. 8). At this time, the movement of the stretching rod 3 is stopped. The state of step 310 is shown in FIG. 5(B).

Next, with the injection port 5 closed, the blow nozzle 1 is pulled away from the blow cavity mold 100 and the molded product 52 (step 312 in FIG. 8). The state of step 312 is shown in FIG. 5(C). The connected blow split molds 100A and 100B are separated to be in the state shown in FIG.

The finished molded article 52 is removed from the blow cavity mold 100 (step 314) and transported to the removal station 208 shown in FIG. 7 (step 316 in FIG. 8). At the take-out station 208, the molded product 208 is taken out as a product.

Next, the preforms for the next cycle are prepared (step 318 in FIG. 8) and the process returns to step 300 and the process described above is repeated in the cycle. The preforms for the next cycle are prepared by injecting the preforms at the injection station 202 in FIG. good.

As described above, according to the blow nozzle 1 according to the first embodiment of the present invention, the reciprocating motion of the stretching rod 3 can be achieved by a very simple configuration in which the closing portion 10 is provided on the stretching rod 3 for stretching the preform. Only by stretching the preform, the injection port 5 can be opened and closed. Therefore, according to the blow nozzle 1 according to the first embodiment, even if the liquid used for blow molding in the previous cycle remains in the fluid passage 7, the remaining liquid From the state of FIG. 3(B) to the state of FIG. 4(A), there is no possibility of dropping into the temperature-controlled preform of the next cycle, and molding defects are prevented. can be done. In particular, the residual liquid tends to drop because vibration occurs in the mold closing operation shown in FIG. 3(B). This can be reliably prevented before it happens. Of course, in this embodiment, it is possible to prevent the residual liquid from dropping onto the preform even in the state immediately before molding shown in FIG. 4(A).

Also, when the blow nozzle 1 is used in a rotary transfer blow molding machine 200 or the like shown in FIG. This eliminates the possibility that the liquid will drop onto the preform through the relevant parts or the like.

Further, according to this embodiment, since the closing portion 10 is formed in the vicinity of the tip 7 of the stretching rod 3 , that is, in a place other than the tip 7 , the tip has an optimum shape when the tip 7 contacts the bottom of the preform 50 . 7 shapes can be selected. For example, the shape of the tip 7 can be rounded without corners so as not to concentrate pressure.

Next, the detailed operation of step 304 in FIG. 8 will be described using the flowchart in FIG.

As shown in FIG. 9, step 304 of FIG. 8 starts with moving (lowering) the stretching rod 3 toward the bottom of the blow cavity mold 100 from the state of FIG. ).

As the extension rod 3 descends, the closed injection port 5 is opened (step 401). Further, as shown in FIG. 4B, the descending stretch rod 3 reaches the bottom of the preform 50 and stretches the preform 50 longitudinally (step 402).

Next, the fluid is introduced into the nozzle body 2 through the port 6 (step 403), the fluid is ejected from the ejection port 5 (step 404), and the preform is laterally stretched by the fluid (step 408). The jetted fluid stretches the preform not only in the horizontal direction but also in the vertical direction. The preform 51 thus stretched is molded by the molding surface 102 of the blow cavity mold 100 (step 404). As shown in FIG. 4B, it will be appreciated that the preform 51 being stretched reaches the molding surface 102 where it is molded.

The longitudinal stretching in step 402 is preceded by the horizontal stretching in step 408 in order to prevent misalignment of the bottom of the final container and to adjust the wall thickness distribution of the container by stretching the longitudinal axis first (preliminary stretching). This is because it is easy to mold. However, in the case of thick-walled containers containing cosmetics and the like, which are not often subjected to vertical axis stretching, and small containers containing pharmaceuticals, etc., the vertical axis stretching and the horizontal axis stretching may be carried out simultaneously, or the horizontal axis stretching may be carried out first. It is also possible to do

The operation when the fluid supply unit 13 shown in FIG. 6 is used for introducing the fluid into the blow nozzle 1 in step 403 of FIG. 9 is as follows. That is, with the on-off valve WV1, the air supply valve WV2 and the vacuum suction valve WV5 closed and the air release valve WV4 open, the water supply valve WV3 is opened to store a predetermined amount of liquid in the storage portion 64. FIG. Next, the water supply valve WV3 and the air release valve WV4 are closed after the completion of liquid storage. Air supply valve WV2 is opened to pressurize the liquid with compressed air. When the reservoir 64 reaches a predetermined pressure, the on-off valve WV1 is opened to introduce a mixture of liquid and gas (pressurized medium) into the blow nozzle 1 through the supply passage 14 and the port 6, thereby blowing the preform 50. Blow molding is carried out.

After the blow molding is completed (the state of FIG. 4C), the air supply valve WV2 is closed and the air release valve WV4 is opened to exhaust excess gas from the circuit of the molded product 52 (container) and the fluid supply unit 13. Then, the pressure inside the molded product 52 (container) is reduced (another exhaust valve may be installed near the blow nozzle). After completion of decompression, the on-off valve WV1 is closed. The extension rod 3 is lifted, and the closing part 10 closes the injection port 5 in a liquid-tight state (steps 308 and 310 in FIG. 8, states of FIGS. 5A and 5B). After the completion of the liquid-tightness, the blow nozzle 1 is raised (state shown in FIG. 5(C)). At this time, the vacuum suction valve WV5 is opened to remove residual liquid in the nozzle body. After removing the residual liquid, the molded product is carried out and the suction valve WV5 is closed.

By using the fluid supply unit 13 shown in FIG. 6, the liquid (water) is pushed out by the pressure applied to the gas (compressed air). The pressure of the medium mixture can be controlled on the basis of the gas pressure. That is, the preform can be blow-molded without using a device for directly applying pressure to the liquid, and the system can be simplified. Furthermore, incompressible fluids (liquids) are superior to compressible fluids (gases) in terms of characteristics as a pressurized medium, and improvement in formability and moldability can be expected. In addition, as a result, the preform can be blown into a desired shape even by using a low-pressure gas. It becomes possible to divert the generation unit.

(Second embodiment)
FIG. 10 shows a blow nozzle 1b according to a second embodiment of the invention. In addition, the same code|symbol is attached|subjected about the same component as 1st Embodiment, and detailed description is abbreviate|omitted.

In the blow nozzle 1 according to the first embodiment, the tip 9 of the stretching rod 3 was not in contact with the bottom of the preform 50 in the state before blow molding shown in FIG. 4(A). Therefore, in the first embodiment, the tip of the stretching rod 3 did not contact the bottom of the preform even after the stretching rod 3 started to descend and the injection port 5 was released from being closed.

On the other hand, in the blow nozzle 1b according to the second embodiment, the tip 9b of the stretching rod 3b touches the bottom of the preform 50 before blow molding, that is, in a state where the closing part 10b closes the injection port 5. A closing portion 10b is formed relatively distant from the tip 9b so as to contact. Therefore, the vertical axis stretching (preliminary stretching) of the preform 50 becomes possible at the same time when the stretching rod 3b starts to descend. Thus, in the second embodiment, longitudinal axis stretching (preliminary stretching) can be performed before closing of the injection port 5 is released. There is no danger of dropping to 50, and preliminary stretching can proceed without any problems.

In the second embodiment, in the state before blow molding corresponding to FIG. 4A, the tip 9b of the stretching rod 3b is not in contact with the bottom of the preform, and the injection port 5 is not closed by the closing portion 10b. Closure 10b may be formed at a position relatively distant from tip 9b such that tip 9b contacts preform 50 when stretch rod 3b is lowered to a position just prior to release. The closing portion 10b of this modification is farther from the tip than the closing portion 10 of the first embodiment, but is formed closer to the tip than the closing portion 10b shown in FIG. Also in such a modification, it is possible to eliminate the possibility that the residual liquid will drop from the injection port 5 to the preform 50 during the preliminary stretching.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples, and can be arbitrarily and suitably modified within the scope of the present invention.

For example, the preform 50 to be molded by the blow nozzle 1 of the present invention is not limited to the preform injection-molded in the injection molding station 202, and the preform may be a primary blow-molded product obtained by primary blow molding. good. In other words, the blow cavity mold 100 shown in FIGS. 3 to 5 may be a secondary blow cavity mold, and the present invention is used when blow molding a secondary blow molded product (molded completed product) from a primary blow molded product. may apply.

Also, the fitting of the nozzle tip 4 to the mouth of the preform in step 302 may include the embodiment shown in FIGS. Also included is a mode in which the blow nozzle 1 is held in a state in which the injection port 5 of the nozzle tip 4 is aligned with the mouth opening of the preform 50 through a target member.

Also, the blow cavity mold 100 is not limited to the examples of FIGS. A mold may be used.

Furthermore, in the first and second embodiments, the closing portions 10 and 10b are formed as large-diameter portions of the rod body. A mode of covering the outer peripheral wall of the nozzle body around the injection port is also conceivable.

Reference Signs List 1, 1b blow nozzle 2 nozzle body 3, 3b extension rod 4 nozzle tip 5 injection port 6 port 7 fluid passage 8 gap 9 tip 10, 10b closure 11 through hole 12 inner peripheral wall

Claims (8)

A blow nozzle for use in a blow molding apparatus for blow molding preforms, comprising:
a nozzle body;
an extension rod inserted through the nozzle body;
with
The nozzle body is
a nozzle tip provided at the tip of the nozzle body so as to be compatible with the mouth of the preform;
an injection port formed at the tip of the nozzle;
a port for introducing fluid, including at least liquid, into the nozzle body;
a fluid passage formed in the nozzle body so as to communicate with the port and the injection port;
with
The stretching rod passes through a section extending in the axial direction of the fluid passage leading to the injection port, and extends between a position where the stretching rod is further projected from the injection port and a position where the stretching rod is retracted to stretch the preform. axially reciprocable with respect to said nozzle body between and said extension rod comprises a closure;
The closing part closes the injection port when the extension rod is in the retracted position, and releases the closure of the injection port when the extension rod moves to the position where the extension rod protrudes further,
the port comprises a first port through which liquid is introduced and a second port through which air is introduced;
a fluid that is a mixture of introduced liquid and air flows through the fluid passage;
A blow nozzle characterized by: The stretching rod comprises a straight rod body inserted through the blow nozzle,
2. The blow nozzle of claim 1, wherein the closure is an enlarged diameter portion of the rod body that fits within the inner peripheral wall of the nozzle body defining the fluid passageway. 3. The blow nozzle according to claim 2, wherein the large diameter portion has a seal portion on an outer peripheral portion that engages with the inner peripheral wall. A method for blow molding a preform using the blow nozzle according to any one of claims 1 to 3 , comprising setting the temperature-controlled preform in a blow cavity mold,
fitting the nozzle tip of the blow nozzle with the closing part closed to the mouth of the preform;
By moving the stretching rod toward the bottom of the blow cavity mold and introducing the fluid into the nozzle body, the preform is stretched by the moving stretching rod and the fluid jetted from the opened injection port stretching the preform;
after the stretched preform has been completely molded by the blow cavity mold, moving the stretch rod away from the bottom of the blow cavity mold to close the injection port. 5. The method of claim 4 , further comprising pulling the blow nozzle away from the blow cavity mold and finished product with the jet closed by the step of closing the jet. 6. The method of claim 5 , wherein the step of moving the blow nozzle away from setting the preform in the blow cavity mold is repeated for the next cycle of preforms. The blow cavity mold comprises at least two blow split molds,
7. A method according to any one of claims 4 to 6 , wherein the step of setting the preform in a blow cavity mold comprises closing the blow split mold. wherein, in the step of fitting the tip of the blow nozzle, the tip of the stretch rod is in contact with the bottom of the preform when the closure is closed or before the closure is released. Item 8. The method according to any one of Items 4 to 7 .

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