Patent Description:
Synthetic resin containers, typical examples of which include polypropylene (PP) bottles and polyethylene terephthalate (PET) bottles, are used to contain, as content liquids, a variety of liquids, such as beverages, cosmetics, pharmaceuticals, detergents, and toiletries including shampoo. Such a container is typically manufactured by blow molding a preform that has been formed, for example, in a bottomed tubular shape using a thermoplastic synthetic resin material as mentioned above.

As a blow molding apparatus for molding a preform into a container, a liquid blow molding apparatus that uses a pressurized liquid, instead of pressurized air, as a pressurizing medium to be supplied into the preform is known.

As the liquid blow molding apparatus, a known liquid blow molding apparatus includes a nozzle unit that has a supply path for a liquid and a blow nozzle, a pressurized liquid supply unit that is connected to the supply path, and a sealing body that is arranged inside the supply path and that opens and closes the supply path. The pressurized liquid supply unit is operated in a state in which the blow nozzle is engaged to a mouth of a synthetic resin preform that has been heated in advance to a temperature at which stretchability may be achieved and that has been placed in a mold used for blow molding and in which the sealing body is moved to its opening position. By doing so, the pressurized liquid is supplied into the preform through the supply path and the blow nozzle, so as to mold the preform into a container having a predetermined shape corresponding to a cavity of the mold. According to such a liquid blow molding apparatus, a content liquid, such as a beverage, that is to be ultimately contained in a container as a product may be used as a liquid supplied to the preform. Thus, the container can be molded while the content liquid is filled into the container. The liquid-filled container containing the content liquid can therefore be easily molded.

Here, the pressurized liquid supply unit included in the liquid blow molding apparatus as described above includes, for example, a liquid supply source that supplies a liquid, and a plunger pump that is connected to the liquid supply source, that draws the liquid supplied from the liquid supply source, and that delivers (pumps) the liquid to the supply path at a predetermined pressure. The plunger pump includes a tubular cylinder and a piston that can move in the axial direction inside the cylinder.

To change the type of liquid (content liquid) supplied to a preform in such a liquid blow molding apparatus, it is necessary to clean the inside of the apparatus, including the plunger pump, so as to prevent contamination (entry of impurities). As a method for cleaning the inside of such an apparatus, a cleaning method referred to as Cleaning in Place (CIP) designed for automatic cleaning using flow of a cleaning liquid or the like into the apparatus without dismantling the apparatus is known.

For example, Patent Literature <NUM> describes a method for cleaning a sealing portion of a piston that slides on an inner surface of a cylinder, wherein a cleaning liquid is circulated in a state in which the sealing portion has been moved to a large-diameter portion of the cylinder.

Further the disclosure of <CIT> may be helpful for understanding the present invention. <CIT> refers a to high pressure slurry plunger pump, which provides a clean fluid buffer around the suction and discharge valves of the pump and in some cases in the vicinity of the plunger seal mechanism in order to displace erosive slurry material and thus extend the life of the pump and improve pump efficiency.

However, in a case in which the sealing portion of the piston is arranged in the large-diameter portion of the cylinder as described above, the piston cannot be restricted in the radial direction with respect to the cylinder, and it can easily assume an unstable position. This may lead to problems, such as damage to the sealing portion or drop-off of a sealing member like an O-ring, for example due to changes in the position or misalignment of the piston when the plunger pump is operated again after cleaning.

It would be helpful to provide a plunger pump wherein the sealing portion of the piston can be cleaned in a stable state, and a liquid blow molding apparatus.

The present invention refers to a plunger pump according to claim <NUM> and a corresponding liquid blow molding apparatus according to claim <NUM>. Advantageous embodiments may include features of depending claims.

A plunger pump according to the present invention is capable of drawing in a liquid from an inlet flow path and delivering the liquid to an outlet flow path at a predetermined pressure and includes:.

In a preferred embodiment of the present plunger pump configured as above, the at least one cleaning liquid circulation groove is configured by a through hole, and
a discharge flow path for discharging a cleaning liquid is provided on an outer side in a radial direction of the at least one cleaning liquid circulation groove.

In another preferred embodiment of the present plunger pump configured as above, the at least one cleaning liquid circulation groove includes a plurality of cleaning liquid circulation grooves arranged at intervals in a circumferential direction on the inner peripheral surface of the cleaning tubular portion.

In still another preferred embodiment of the present plunger pump configured as above, the plurality of cleaning liquid circulation grooves as a whole extends around an entire circumference of the inner peripheral surface of the cleaning tubular portion.

In still another preferred embodiment of the present plunger pump configured as above, the plurality of cleaning liquid circulation grooves is arranged so that any two cleaning liquid circulation grooves adjacent to each other in the circumferential direction partially overlap each other in an axial direction.

A liquid blow molding apparatus according to the present invention supplies a pressurized liquid into a synthetic resin preform, to thereby blow mold the preform into a container with a predetermined shape and includes:.

According to the present disclosure, a plunger pump wherein the sealing portion of the piston can be cleaned in a stable state, and a liquid blow molding apparatus can be provided.

Hereinafter, the present disclosure will be described by illustration in more detail with reference to the drawings.

<FIG> illustrates a plunger pump <NUM> according to an embodiment of the present disclosure. The plunger pump <NUM> includes a cylinder <NUM> and a piston <NUM>. The plunger pump <NUM> is connected to a piping member <NUM> that constitutes an inlet flow path R1 and an outlet flow path R2. The plunger pump <NUM> is configured to draw in a liquid from the inlet flow path R1 and deliver the liquid toward the outlet flow path R2 at a predetermined pressure.

In this example, the cylinder <NUM> is cylindrical, and an opening <NUM> is provided at one end (in this example, at the upper end) in an axial direction (direction along an axis O) of the cylinder <NUM>. The cylinder <NUM> has an internal space S that communicates with the inlet flow path R1 and the outlet flow path R2 via the opening <NUM>. Additionally, although in this example one opening <NUM> serves as both an inlet port for drawing in a liquid from the inlet flow path R1 and an outlet port for delivering the liquid to the outlet flow path R2, the present disclosure is not limited to this. An intake port and an outlet port may be provided separately in the cylinder <NUM>. Further, the cylinder <NUM> is not limited to cylindrical, and it may also have a tubular shape with a cross-section other than circular.

The cylinder <NUM> includes a body tubular portion <NUM> in which a head <NUM> of the piston <NUM> is arranged during normal use of the plunger pump <NUM> (when it is not cleaned), and a cleaning tubular portion <NUM> in which the head <NUM> is arranged when the plunger pump <NUM> is cleaned.

The body tubular portion <NUM> and the cleaning tubular portion <NUM> have inner diameters equal to each other, and they are coaxially arranged so that respective inner peripheral surfaces 22a, 23a are continuous with each other. That is, the inner peripheral surface 22a of the body tubular portion <NUM> and the inner peripheral surface 23a of the cleaning tubular portion <NUM> are smoothly continuous without a step. Accordingly, the head <NUM> of the piston <NUM> can move smoothly between the body tubular portion <NUM> and the cleaning tubular portion <NUM>. Additionally, if the inner peripheral surface 22a of the body tubular portion <NUM> and the inner peripheral surface 23a of the cleaning tubular portion <NUM> are smoothly continuous without a step, the inner diameter of the body tubular portion <NUM> may be different from that of the cleaning tubular portion <NUM> to the extent that rattling can be controlled.

The cleaning tubular portion <NUM> in this example is located under (at a lower side in the vertical direction of) the body tubular portion <NUM>. The inner peripheral surface 23a of the cleaning tubular portion <NUM> is provided with cleaning liquid circulation grooves <NUM> that extend obliquely with respect to the axis O. The cleaning liquid circulation grooves <NUM> in this example are configured by through holes that pass through the cleaning tubular portion <NUM> in the radial direction. The cleaning liquid circulation grooves <NUM> may also be configured by recesses that do not pass through the cleaning tubular portion <NUM>. In that case, preferably, a flow path or the like for discharging the cleaning liquid is separately provided below the cleaning liquid circulation grooves <NUM>.

Each cleaning liquid circulation groove <NUM> extends obliquely with respect to the axis O. That is, the cleaning liquid circulation groove <NUM> extends spirally around the axis O. The cleaning liquid circulation groove <NUM> in this example is configured so as to have a substantially parallelogram shape when viewed from the axis O. The cleaning liquid circulation groove <NUM> has an upper side 24a and a lower side 24b that are perpendicular to the axis O, and a right side 24c and a left side 24d that extend obliquely with respect to the axis O. Additionally, the shape of the cleaning liquid circulation groove <NUM>, which extends obliquely with respect to the axis O, may be changed as appropriate. The cleaning liquid circulation groove <NUM> is not limited to a shape that extends linearly along the direction of its extension as in this example, and it can have a curved portion, a bent portion, or the like. Further, although the cleaning liquid circulation groove <NUM> in this example has a groove width perpendicular to the axis O that is constant over the whole cleaning liquid circulation groove <NUM>, the groove width may vary in part. Moreover, although in this example a plurality of cleaning liquid circulation grooves <NUM> is included, only a single cleaning liquid circulation groove <NUM> may be provided on the inner peripheral surface 23a of the cleaning tubular portion <NUM>. In that case, the single cleaning liquid circulation groove <NUM> preferably extends spirally around the entire circumference of the inner peripheral surface 23a of the cleaning tubular portion <NUM>.

In this example, a plurality of cleaning liquid circulation grooves <NUM> is formed at intervals in the circumferential direction on the inner peripheral surface 23a of the cleaning tubular portion <NUM>. The plurality of cleaning liquid circulation grooves <NUM> is arranged at regular intervals in the circumferential direction around the entire circumference of the inner peripheral surface 23a of the cleaning tubular portion <NUM>. Additionally, although in this example each of the plurality of cleaning liquid circulation grooves <NUM> has the same shape, the present disclosure is not limited to this. Cleaning liquid circulation grooves <NUM> with different shapes may be included.

A support portion <NUM> is formed between two cleaning liquid circulation grooves <NUM> that are adjacent to each other in the circumferential direction on the inner peripheral surface 23a of the cleaning tubular portion <NUM>. The support portions <NUM> are inclined with respect to the axis O, as is the case with the cleaning liquid circulation grooves <NUM>. In this example, a plurality of support portions <NUM> is evenly arranged in the circumferential direction of cleaning tubular portion <NUM>.

The plurality of cleaning liquid circulation grooves <NUM> as a whole extends around the entire circumference of the inner peripheral surface 23a of the cleaning tubular portion <NUM>. That is, different cleaning liquid circulation grooves <NUM> are present at different positions in the axial direction, around the entire circumference of the inner peripheral surface 23a of the cleaning tubular portion <NUM>. With such a configuration, when the piston <NUM> is moved in the axial direction (moved upward and downward) inside the cleaning tubular portion <NUM>, the entire circumference of a sealing portion <NUM> of the piston <NUM> can be cleaned.

In this example, the plurality of cleaning liquid circulation grooves <NUM> is arranged so that any two cleaning liquid circulation grooves <NUM> adjacent to each other in the circumferential direction partially overlap each other in the axial direction. That is, for example, any two cleaning liquid circulation grooves <NUM> adjacent to each other in the circumferential direction are arranged so that an upper portion of one cleaning liquid circulation groove <NUM> and a lower portion of the other cleaning liquid circulation groove <NUM> overlap each other in the axial direction. With such a configuration, when the head <NUM> of the piston <NUM> is moved in the axial direction (upward and downward) inside the cleaning tubular portion <NUM>, the entire circumference of the sealing portion <NUM> of the piston <NUM> can be cleaned more effectively.

The head <NUM> of the piston <NUM> is configured to be always restricted by the support portions <NUM> around the entire cleaning tubular portion <NUM> in the axial direction. That is, at any position in the axial direction of the cleaning tubular portion <NUM>, there is appropriately a support portion <NUM> that supports the head <NUM> of the piston <NUM> from the outer side in the radial direction. Accordingly, even when the head <NUM> of the piston <NUM> is moved in the axial direction inside the cleaning tubular portion <NUM>, the position and location of the piston <NUM> can be maintained in a stable state.

The cleaning liquid circulation grooves <NUM> communicate with a cleaning liquid discharge port <NUM> via a discharge flow path <NUM> provided on the outer side in the radial direction of the cleaning liquid circulation grooves <NUM>. The discharge flow path <NUM> may be an annular space that extends around the entire circumference of the cleaning tubular portion <NUM>, or it may be a space that is present only in part in the circumferential direction. The cleaning liquid discharge port <NUM> in this example is located at a lower end of the discharge flow path <NUM>, and it opens to the outer side in the radial direction. The cleaning liquid discharge port <NUM> may be an annular opening that extends around the entire circumference of the cleaning tubular portion <NUM>, or it may be an opening that is present only in part in the circumferential direction.

Additionally, the cylinder <NUM> may be formed by combining a plurality of members as in this example, or it may be a single member molded entirely in one piece.

The cylinder <NUM> in this example includes an upper tubular member <NUM> that is connected to the piping member <NUM>, and a lower tubular member <NUM> that is connected to a lower end of the upper tubular member <NUM> via a connecting member <NUM>. An upper outer tubular member <NUM> and a lower outer tubular member <NUM> are further provided on the outer side in the radial direction (closer to an outer periphery) of the lower tubular member <NUM>, and an annular support tubular member <NUM> is provided under the lower tubular member <NUM>. In this example, the body tubular portion <NUM> is configured by the upper tubular member <NUM> and the connecting member <NUM>, and the cleaning tubular portion <NUM> is configured by the lower tubular member <NUM>. The discharge flow path <NUM> is formed between the lower tubular member <NUM> and the upper outer tubular member <NUM>, and the cleaning liquid discharge port <NUM> is formed between the upper outer tubular member <NUM> and the lower outer tubular member <NUM>. The inner peripheral surface of the support tubular member <NUM> is configured to slide against the outer peripheral surface of a piston rod <NUM>.

Here, the piping member <NUM> can be cylindrical, for example. In the piping member <NUM> in this example, a hole <NUM> is formed so as to pass through its side wall. The cylinder <NUM> is connected so that the opening <NUM> of the cylinder <NUM> is arranged in the hole <NUM> of the piping member <NUM>.

The piping member <NUM> is provided with an annular inclined surface <NUM> that surrounds the hole <NUM>, and a fitting recess <NUM> is provided adjacent to the inclined surface <NUM>. In this example, an upper end of the upper tubular member <NUM> (body tubular portion <NUM>) of the cylinder <NUM> is fitted into the annular fitting recess <NUM> provided in the piping member <NUM>.

A sealing member <NUM> is arranged at the joint between the cylinder <NUM> and the piping member <NUM>. In this example, the sealing member <NUM> configured by a ring-shaped packing or the like is fitted into an attachment groove 22b formed at an upper end of the inner peripheral surface 22a, so that the sealing member <NUM> is exposed to the internal space S. The sealing member <NUM> is sandwiched between the upper tubular member <NUM> and the piping member <NUM> in the axial direction. By thus arranging the ring-shaped sealing member <NUM> at a position that is exposed to the internal space S, it can be further ensured that entry of liquid into the joint between the piping member <NUM> and the cylinder <NUM> (joint between the piping member <NUM> and the upper tubular member <NUM>) is prevented.

The piston <NUM> is arranged so as to be movable in the axial direction in the internal space S of the cylinder <NUM>. The piston <NUM> includes the head <NUM> and the piston rod <NUM>. The head <NUM> is columnar, with an outer peripheral surface 41a being shaped in accordance with the shape of the inner peripheral surface of the cylinder <NUM>. The piston rod <NUM> is columnar, with a diameter smaller than the head <NUM>. In this example, the head <NUM> and the piston rod <NUM> are cylindrical. A driving device (which is not illustrated) is provided at a base end of the piston rod <NUM>, so as to move the piston <NUM> in the axial direction.

The sealing portion <NUM> is provided on the outer peripheral surface 41a of the head <NUM>. The sealing portion <NUM> slides against the inner peripheral surfaces 22a, 23a of the cylinder <NUM>. The sealing portion <NUM> in this example is configured by an annular (ring-shaped) O-ring 43a provided on the outer peripheral surface 41a of the head <NUM>, and a pair of annular (ring-shaped) wear rings 43b, 43c located above and below the O-ring 43a. The O-ring 43a and the wear rings 43b, 43c are respectively fitted into annular grooves 41b, 41c, and 41d formed on the outer peripheral surface 41a of the head <NUM>.

The configuration of the sealing portion <NUM> provided on the outer peripheral surface 41a of the head <NUM> is not limited to the illustrated example. The material, number, arrangement, or the like of the sealing portion <NUM> can be determined as appropriate, if it can slide against the inner peripheral surfaces 22a, 23a of the cylinder <NUM> and ensure airtightness between the piston <NUM> and the cylinder <NUM>.

When the aforementioned plunger pump <NUM> described above is to be cleaned (CIP cleaned), the head <NUM> of the piston <NUM> is arranged in the cleaning tubular portion <NUM> of the cylinder <NUM>, and a cleaning liquid is circulated into the cleaning liquid circulation grooves <NUM>, as illustrated by the arrow in <FIG>. By arranging the head <NUM> in the cleaning tubular portion <NUM> of the cylinder <NUM>, the sealing portion <NUM> is exposed to the cleaning liquid circulation grooves <NUM>, so that the cleaning liquid flowing in the cleaning liquid circulation grooves <NUM> can be used to clean the sealing portion <NUM> of the piston <NUM>. At this time, the entire sealing portion <NUM> can be more effectively cleaned, by circulating the cleaning liquid into the cleaning liquid circulation grooves <NUM> while the piston <NUM> is reciprocated in the axial direction (moved upward and downward).

The support portions <NUM> support the outer peripheral surface 41a of the head <NUM> of the piston <NUM> and the sealing portion <NUM> that are located in the cleaning tubular portion <NUM> from the outer side in the radial direction. That is, the head <NUM> of the piston <NUM> located in the cleaning tubular portion <NUM> is restricted in the radial direction by the support portions <NUM> on the inner peripheral surface 23a of the cleaning tubular portion <NUM>. The piston <NUM> is therefore maintained in a stable state during cleaning. As a result, inclination of the position, misalignment, or the like of the piston <NUM> during cleaning can be prevented. In particular, because in this example a plurality of support portions <NUM> arranged at intervals in the circumferential direction of the cleaning tubular portion <NUM> supports the outer peripheral surface 41a of the head <NUM> of the piston <NUM> in the circumferential direction in a well-balanced manner, the position and location of the head <NUM> of the piston <NUM> located in the cleaning tubular portion <NUM> are more easily stabilized.

As described above, the plunger pump <NUM> according to the present embodiment is a plunger pump <NUM> that is capable of drawing in a liquid from an inlet flow path R1 and delivering the liquid to an outlet flow path R2 at a predetermined pressure, the plunger pump <NUM> including a tubular cylinder <NUM> that has an internal space S communicating with the inlet flow path R1 and the outlet flow path R2, and a piston <NUM> that is movable along an axis O of the cylinder <NUM>, wherein a head <NUM> of the piston <NUM> is provided, on an outer peripheral surface 41a thereof, with a sealing portion <NUM> that is slidable against an inner peripheral surface 22a of the cylinder <NUM>, the cylinder <NUM> includes a body tubular portion <NUM> in which the head <NUM> is arranged during normal use, and a cleaning tubular portion <NUM> in which the head <NUM> is arranged during cleaning, an inner peripheral surface 23a of the cleaning tubular portion <NUM> has an inner diameter equal to an inner diameter of the inner peripheral surface 22a of the body tubular portion <NUM>, the cleaning tubular portion <NUM> is provided, on the inner peripheral surface 23a thereof, with at least one cleaning liquid circulation groove <NUM> that is configured by a through hole (or a recess), and the at least one cleaning liquid circulation groove <NUM> extends obliquely with respect to the axis O. With such a configuration, when the plunger pump <NUM> is cleaned (CIP cleaned), the sealing portion <NUM> of the piston <NUM> can be appropriately cleaned in a state in which the head <NUM> of the piston <NUM> is restricted in a radial direction with respect to the cylinder <NUM>.

Thus, according to the plunger pump <NUM> of the present embodiment, the sealing portion <NUM> of the piston <NUM> can be cleaned in a stable state. Accordingly, when it is operated again after cleaning, damage to the sealing portion <NUM>, drop-off of a sealing member (the O-ring 43a and the wear rings 43b, 43c), or the like caused by changes in the position or misalignment of the piston <NUM>, or the like can be prevented.

In the plunger pump <NUM> according to the present embodiment, the at least one cleaning liquid circulation groove <NUM> is configured by a through hole, and a discharge flow path <NUM> for discharging a cleaning liquid is provided on an outer side in a radial direction of the at least one cleaning liquid circulation groove <NUM>. With such a configuration, the cleaning liquid that has circulated in the at least one cleaning liquid circulation groove <NUM> can be smoothly discharged. This in turn prevents the cleaning liquid from flowing back toward the internal space S and reducing the cleaning effect, for example.

In the plunger pump <NUM> according to the present embodiment, the at least one cleaning liquid circulation groove <NUM> includes a plurality of cleaning liquid circulation grooves <NUM> arranged at intervals in a circumferential direction on the inner peripheral surface 23a of the cleaning tubular portion <NUM>. With such a configuration, the sealing portion <NUM> of the piston <NUM> can be cleaned more efficiently compared with a case in which there is only one cleaning liquid circulation groove <NUM>.

In the plunger pump <NUM> according to the present embodiment, the plurality of cleaning liquid circulation grooves <NUM> as a whole extends around an entire circumference of the inner peripheral surface 23a of the cleaning tubular portion <NUM>. With such a configuration, the sealing portion <NUM> of the piston <NUM> can be efficiently cleaned around its entire circumference.

In the plunger pump <NUM> according to the present embodiment, the plurality of cleaning liquid circulation grooves <NUM> is arranged so that any two cleaning liquid circulation grooves <NUM> adjacent to each other in the circumferential direction partially overlap each other in an axial direction. With such a configuration, the sealing portion <NUM> of the piston <NUM> can be more efficiently cleaned around its entire circumference.

Now, <FIG> is a schematic view illustrating a liquid blow molding apparatus <NUM> that includes a plunger pump <NUM>. The liquid blow molding apparatus <NUM> is capable of supplying a pressurized liquid into a synthetic resin preform P, to thereby blow mold the preform P into a container with a predetermined shape.

The liquid blow molding apparatus <NUM> includes, for example, the plunger pump <NUM>, a liquid supply source <NUM> that is connected to the plunger pump <NUM> via the inlet flow path R1, and a nozzle unit <NUM> (injection apparatus) that is connected to the plunger pump <NUM> via the outlet flow path R2 and that supplies a liquid to the preform P arranged in a mold <NUM>.

The liquid supply source <NUM> can be, for example, a supply tank that contains a liquid. The supply tank may be configured to contain the liquid and to heat or cool the liquid to a predetermined temperature and hold it at the temperature. An opening and closing valve V is provided in the inlet flow path R1 (piping member <NUM>) between the plunger pump <NUM> and the liquid supply source <NUM>. The opening and closing valve V can be used to open and close the inlet flow path R1. Additionally, a pressure gauge <NUM> may be provided in the outlet flow path R2.

The nozzle unit <NUM> is arranged above the mold <NUM>. The nozzle unit <NUM> can be driven by a driving device that is not illustrated, so as to move in the vertical direction closer to and away from the mold <NUM>. The nozzle unit <NUM> includes a supply path 3a for a liquid, a blow nozzle 3b provided at an end of the supply path 3a, and a sealing body 3c provided inside the supply path 3a. The supply path 3a is connected to the outlet flow path R2. The sealing body 3c is configured to open and close the supply path 3a. The mold <NUM> has a cavity 4a with a shape, such as a bottle shape, that corresponds to the final shape of the container.

When a liquid-filled container is to be molded using the liquid blow molding apparatus <NUM>, the head <NUM> of the piston <NUM> of the plunger pump <NUM> is arranged in the body tubular portion <NUM> of the cylinder <NUM>, so that it moves in the axial direction within the range of the body tubular portion <NUM>.

The plunger pump <NUM> can supply a liquid that has been pressurized to a predetermined pressure to the blow nozzle 3b via the outlet flow path R2 and the supply path 3a, by operating (in this example, raising) the piston <NUM> in a pressurizing direction in a state in which the sealing body 3c is in the opening position so as to open the supply path 3a and in which the opening and closing valve V is closed. The plunger pump <NUM> can also draw the liquid contained in the liquid supply source <NUM> into the internal space S of the cylinder <NUM> of the plunger pump <NUM>, by operating (in this example, lowering) the piston <NUM> in a drawing direction in a state in which the sealing body 3c is in the closing position so as to close the supply path 3a and in which the opening and closing valve V is opened.

As the preform P, for example, a preform formed in a shape including a cylindrical mouth serving as an opening end, and a bottomed cylindrical body continuous with the mouth may be used. A thermoplastic resin material, such as polypropylene (PP) or polyethylene terephthalate (PET), may be injection molded to form the preform P. The preform P is not limited to the above example, and various shapes and materials can be used. For example, as the preform P, a preform with a laminated structure including a plurality of integrally laminated layers can be used.

According to the liquid blow molding apparatus <NUM>, the blow nozzle 3b is engaged with the mouth of the synthetic resin preform P that has been heated in advance to a temperature at which stretchability can be achieved and that has been placed in the mold <NUM>, and the plunger pump <NUM> is operated so as to supply a pressurized liquid into the preform P. By doing so, the preform P can be molded into a container with a predetermined shape corresponding to the cavity 4a of the mold <NUM>, while the liquid can be contained inside the container. According to such a liquid blow molding apparatus <NUM>, by using a content liquid, such as a beverage, that is to be ultimately contained in the container as a product, as the liquid supplied to the preform P, molding of the container and filling of the content liquid into the container can be performed simultaneously, so that the liquid-filled container containing the content liquid can be easily molded. Accordingly, the step of filling the content liquid into the molded container may be omitted, and the production process and the configuration of production line (apparatus) may be simplified. Additionally, examples of the liquid supplied to the preform P as a pressurized medium in blow molding may include, but is not limited to, various liquids, such as beverages, cosmetics, pharmaceuticals, detergents, toiletries like shampoo.

In the liquid blow molding apparatus <NUM>, for example, in a case in which the type of liquid (content liquid) to be supplied to the preform P is changed, CIP may be performed so as to clean the liquid blow molding apparatus <NUM>, by circulating a cleaning liquid or the like within the apparatus without dismantling it. In particular, in the plunger pump <NUM>, due to the head <NUM> of the piston <NUM> that is arranged in the cleaning tubular portion <NUM> of the cylinder <NUM> (moved in the axial direction within the range of the cleaning tubular portion <NUM>) as described above, the sealing portion <NUM> of the piston <NUM> can be cleaned in a stable state.

Needless to say, the present disclosure is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention as defined by the claims.

For example, although in the above embodiment the plunger pump <NUM> is connected below the piping member <NUM>, so that the axis O of the cylinder <NUM> is orthogonal to the piping member <NUM> extending in the horizontal direction, the extension directions and connection method of the piping member <NUM> and the plunger pump <NUM> are not limited to the illustrated example and can be changed as appropriate.

Further, although in the above embodiment the cleaning liquid that has passed through the inlet flow path R1 of the piping member <NUM> is circulated in the cleaning liquid circulation grooves <NUM> through the opening <NUM> of the cylinder <NUM> and the internal space S, the flow path of the cleaning liquid can be changed as appropriate. For example, instead of introducing the cleaning liquid through the opening <NUM> provided at the upper end of the cylinder <NUM>, a cleaning liquid introduction port that is different from the opening <NUM> may be provided in the cylinder <NUM>. Moreover, although in this example the cleaning liquid that has passed through the cleaning liquid circulation grooves <NUM> passes through the discharge flow path <NUM> located on the outer side in the radial direction of the cleaning liquid circulation grooves <NUM> before being discharged from the cleaning liquid discharge port <NUM>, the present disclosure is not limited to this. A cleaning liquid discharge flow path or the like may be provided at another position.

Claim 1:
A plunger pump (<NUM>) that is capable of drawing in a liquid from an inlet flow path (R1) and delivering the liquid to an outlet flow path (R2) at a predetermined pressure, the plunger pump (<NUM>) comprising:
a tubular cylinder (<NUM>) that has an internal space communicating with the inlet flow path (R1) and the outlet flow path (R2); and
a piston (<NUM>) that is movable along an axis (O) of the cylinder (<NUM>), wherein
a head (<NUM>) of the piston (<NUM>) is provided, on an outer peripheral surface (41a) thereof, with a sealing portion (<NUM>) that is slidable against an inner peripheral surface of the cylinder (<NUM>),
characterized by that
the cylinder (<NUM>) includes a body tubular portion (<NUM>) in which the head (<NUM>) is arranged during normal use, and a cleaning tubular portion (<NUM>) in which the head (<NUM>) is arranged during cleaning,
an inner peripheral surface (23a) of the cleaning tubular portion (<NUM>) has an inner diameter equal to an inner diameter of an inner peripheral surface (22a) of the body tubular portion (<NUM>),
the cleaning tubular portion (<NUM>) is provided, on the inner peripheral surface (23a) thereof, with at least one cleaning liquid circulation groove (<NUM>) that is configured by a through hole or a recess, and
the at least one cleaning liquid circulation groove (<NUM>) extends obliquely with respect to the axis (O).