JP2013060226A - Piston-type measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piston-type measuring instrument having a cylinder and a piston to be used for measuring the quantity of a liquid, which can be automatically, simply, and surely cleaned in place completely without being disassembled at all, while improving cleaning effect, reducing the quantity of a cleaning liquid, working time and costs.SOLUTION: The piston-type measuring instrument 1 sucks and discharges the liquid from the other axial end of the cylinder 8 by moving forward and backward the piston 9 inserted from the one axial end to the other axial end of the cylinder 8. A measuring area La having an inner peripheral face having a constant inner diameter that comes in slide contact with a sealing member 27 provided in the outer periphery of the piston 9 to measure the quantity of the liquid, is provided in the axial middle portion of the cylinder 8. Cleaning areas Lb and Lc having an inner peripheral face having a large diameter that are separated from the piston 9 and the sealing member 27, are continuously formed in each of both axial ends of the measuring area La of the cylinder 8.

Description

  The present invention relates to a piston-type metering device, for example, a piston-type metering device suitable for quantitatively filling a liquid in a container such as a standing pouch, ampoule, and bottle.

In the filling and packaging industry and the like, a piston-type measuring device with high liquid measuring accuracy is used to quantitatively fill a high-viscosity liquid into a container at high speed and high pressure.
In this piston type metering device, every time the liquid to be filled is changed or periodically, the entire device is manually disassembled and cleaned and reassembled. However, manual disassembly and cleaning and reassembly require a long time, increase costs, and have the disadvantage of being damaged due to operational errors.
In view of this, the present applicant has proposed an apparatus that can easily and reliably clean a liquid flow path without disassembling the apparatus (see Patent Document 1).

Japanese Patent Laid-Open No. 08-159999

  The inventors of the present invention conducted further research and completed the present invention by further improving the function and effect of the device described in Patent Document 1.

  The present invention is capable of automatically and simply and reliably performing stationary cleaning without disassembling all the cylinders and pistons used for liquid measurement, improving the cleaning effect, An object of the present invention is to provide a piston-type weighing device that can reduce the amount, shorten the working time, and reduce the cost.

  In order to achieve the above-described object, the piston type metering device according to the first aspect of the present invention is configured to reciprocate a piston inserted from one axial end of a cylinder toward the other axial end of the cylinder. In the piston-type measuring device that sucks and discharges liquid from the other end side, the inner diameter of the inner peripheral surface that measures the liquid by sliding in contact with the sealing member provided on the outer peripheral portion of the piston at the axially intermediate portion of the cylinder is constant. A measuring region is provided, and a cleaning region having a large-diameter inner peripheral surface spaced apart from the piston and the sealing member is continuously formed at both axial ends of the measuring region of the cylinder. .

  According to such a configuration, the axially opposite end portions of the piston can be reliably cleaned by using the cleaning regions at both ends in the axial direction of the cylinder, and the cylinders and the corners of the piston used for liquid measurement can be surely cleaned. Can be cleaned automatically, easily and reliably without disassembly, improving the cleaning effect, reducing the amount of cleaning liquid, shortening the work time, and reducing the cost. Can do.

  Further, the piston-type measuring device according to the second aspect of the present invention reciprocates the piston inserted from one axial end portion of the cylinder toward the other axial end portion of the cylinder from the other end side. In the piston-type metering device for sucking and discharging liquid, the other end in the axial direction of the metering region in which the inner diameter of the inner peripheral surface for metering the liquid in sliding contact with the sealing member provided on the outer peripheral part of the piston of the cylinder is constant A cleaning region having a large-diameter inner peripheral surface spaced apart from the piston and the sealing member is continuously formed.

  According to such a configuration, the axially opposite end portions of the piston can be reliably cleaned using the cleaning region at the other end in the axial direction of the cylinder, and the cylinder and the corner of the piston used for liquid metering can be used. Can be cleaned automatically, easily and securely without disassembly, improving the cleaning effect, reducing the amount of cleaning liquid, shortening the working time, and reducing the cost. be able to.

  Further, in the liquid filling apparatus according to the third aspect of the present invention, the turbulent flow forming means for the cleaning liquid is formed on at least one of the front end surface of the piston and the inner end surface on the other end side in the axial direction of the cylinder facing the piston. It is characterized by being.

  According to such a configuration, the cleaning liquid is generated in the cylinder by the cleaning liquid turbulent flow forming means formed on at least one of the front end face of the piston and the inner end face on the other end side in the axial direction of the cylinder facing the piston. Since the turbulent flow is formed, it is possible to more reliably clean the cylinders and pistons used for liquid metering.

  Moreover, the liquid filling apparatus according to the fourth aspect of the present invention is characterized in that the turbulent flow forming means is formed by an uneven portion that forms a swirling flow of the cleaning liquid inside the cylinder.

  According to such a configuration, since the swirling flow of the cleaning liquid is formed inside the cylinder by the turbulent flow forming means formed by the concavo-convex portions, the swirling flow surely performs cleaning with stronger cleaning ability.

  Further, in the liquid filling apparatus according to the fifth aspect of the present invention, the flow path changing means for causing the cleaning liquid to advance toward the sealing member in the cleaning region is provided on the inner end surface on the other axial end side of the cylinder. It is provided.

  According to such a configuration, the cleaning liquid can be advanced to the narrow portion formed at the connecting portion between the sealing member and the piston, so that the cleaning can be reliably performed.

  The liquid filling apparatus according to the sixth aspect of the present invention is characterized in that the piston is formed to be rotatable around a piston rod as a rotation center.

  According to such a configuration, efficient cleaning can be performed by rotating the cleaning liquid by rotating the piston in the cylinder.

  Further, in the liquid filling apparatus according to the seventh aspect of the present invention, the flow path for sucking and discharging the liquid and the cleaning liquid connected to the inner end surface on the other axial end side of the cylinder is a central axis of the cylinder. It is provided in an eccentric position.

  According to such a configuration, by flowing the cleaning liquid into the cylinder from a position eccentric to the center axis of the cylinder from the flow path for sucking and discharging the liquid and the cleaning liquid, the turbulent flow forming capability is further increased, and more reliable cleaning is performed. Done.

  According to the piston type metering device of the present invention, it is possible to automatically and simply and reliably perform stationary cleaning without disassembling all the cylinders and pistons used for liquid measurement. The effect can be improved, and the excellent effect of reducing the amount of cleaning liquid, shortening the working time, and reducing the cost can be exhibited.

1 is a longitudinal side view showing an example of a liquid filling device using an embodiment of a piston-type metering device according to the present invention. 1 shows an embodiment of a piston-type metering device according to the present invention, wherein (a) is a longitudinal sectional view showing a state where the piston is in a metering region, and (b) is a longitudinal sectional view showing a state where the piston is in an upper cleaning region. , (C) is a longitudinal sectional view showing a state in which the piston is in the lower cleaning region. Enlarged longitudinal sectional view of the cylinder part showing the piston in the upper cleaning area (A) is a plan view showing the upper surface of the piston, (b) a longitudinal sectional view showing a state where the piston is rotating, (c) is a sectional view taken along the line cc of (a). Enlarged sectional view showing the upper lid part of the piston and cylinder

  Hereinafter, an embodiment of a piston-type weighing device according to the present invention will be described with reference to FIGS. 1 to 5. In this embodiment, a piston type weighing device in which cleaning areas are formed at both ends in the axial direction of the cylinder will be described. In the present invention, the cleaning area is formed only at the other axial end of the measuring area. May be. Even in the piston type measuring device in which the cleaning area is formed only at the other axial end of the measuring area, the piston is positioned in the cleaning area formed at one axial end (lower) in the following embodiments. It is assumed that predetermined operational effects other than the operational effects obtained in this case can be obtained, and the description thereof is omitted.

FIG. 1 thru | or FIG. 5 shows one Embodiment of the piston type measuring device 1 of this embodiment.
FIG. 1 shows a liquid filling device 2 for filling a liquid using the piston type metering device 1 of the present embodiment.

  The liquid filling device 2 sucks the liquid in the tank 5 fixed by the support stay 4 on the base 3 placed on the foundation into the piston-type metering device 1 of the present embodiment through the flow path 6, and then A predetermined amount of liquid is discharged from the piston-type metering device 1 through the flow path 7 so as to be sent to a filling unit (not shown).

  In FIG. 1, the piston type metering device 1 of the present embodiment has a central axis in the vertical direction, and two are shown side by side in the figure.

  The outline of each piston-type measuring device 1 will be described. As shown in FIG. The piston 9 is fixed to the upper end portion of the piston rod 10 inserted from one axial end portion (lower end portion in the present embodiment) of the cylinder 8, and the piston rod 10 is fixed to the axial direction of the cylinder 8 by the piston drive mechanism 11. It is reciprocated toward the end (in this embodiment, the upper end). The piston drive mechanism 11 is formed with a ball screw 12. The ball screw 12 is rotatably installed so as to hang vertically downward from the top plate 3a portion of the gantry 3 at the center position of the horizontal projection plane of the six piston-type measuring devices 1, 1. A ball nut body 13 is screwed together, and a lower end portion of each piston rod 10 is fixed to a horizontal plate 14 fixed to the ball nut body 13. A belt 18 is wound between a pulley 15 fixed to the lower end of the ball screw 12 and an output shaft 17 of the drive motor 16. By rotating the drive motor 16 forward and backward to rotate the ball screw 12 forward and backward, the ball nut body 13 and the horizontal plate 14 are moved up and down along the ball screw 12 so that each piston rod 10 and piston 9 are axially moved. Is reciprocated. Each piston rod 10 is supported by a cylindrical support sleeve 19 at a portion where the top plate 3a of the gantry 3 penetrates so that the vertical movement is smooth.

  Each piston-type metering device 1 will be described with reference to FIGS. Since each piston type metering device 1 has the same configuration, only one piston type metering device 1 will be described.

  On the top plate 3 a of the gantry 3, a substrate 21 that supports the cylinder 8 by a plurality of columns 20 is installed horizontally. The lower end portion of the cylinder 8 is fixed by being fitted into a circular hole 22 formed in the substrate 21, and the lower end portion is closed by fixing the lower lid 23 to the lower surface of the substrate 21. The piston rod 10 passes through the lower lid 23. Further, a flow path 24 for discharging the cleaning liquid or the like at the time of cleaning or connecting to the opposite side is connected to a position of the lower lid 23 where the penetrating portion of the piston rod 10 is removed. The upper end portion of the cylinder 8 is closed by screwing the upper lid 25. Sealing is achieved by interposing a packing 26 between them.

  A connecting tube 25 a for connecting to the flow paths 6 and 7 is formed on the central shaft portion of the upper lid 25 so as to protrude upward. Inside the cylinder 8, a measuring region La (in the figure) in which the inner diameter of the inner peripheral surface Sa for measuring the liquid is slidably brought into contact with the sealing member 27 provided on the outer peripheral portion of the piston 9 at the intermediate portion in the axial direction of the cylinder 8. 2 (see (a)), and the cleaning regions Lb, Lc provided with large-diameter inner peripheral surfaces Sb, Sc spaced apart from the piston 9 and the sealing member 27, respectively, at both axial ends of the measuring region La of the cylinder 8 Are formed continuously. In the cleaning region Lb above the cylinder 8, as shown in FIG. 2B, an inner peripheral surface Sb having a large diameter is formed over the range of the axial length in which the entire piston 9 portion is accommodated. Yes. The large-diameter inner peripheral surface Sb has a tapered portion t whose inner diameter gradually increases from the upper end portion of the inner peripheral surface Sa having a constant inner diameter and a maximum inner diameter of the tapered portion t. It is formed by the diameter part f. In the cleaning region Lc below the cylinder 8, as shown in FIG. 2C, an inner peripheral surface Sc having a large diameter is formed over the range of the axial length in which the entire piston 9 portion is accommodated. Yes. The large-diameter inner peripheral surface Sc has a tapered portion t whose inner diameter gradually increases downward from the lower end portion of the inner peripheral surface Sa having a constant inner diameter and a large inner diameter of the tapered portion t. It is formed by the diameter part f.

  Further, the upper surface 9a of the piston 9 is slightly tapered upward, and the inner surface of the upper lid portion 25 is also a tapered surface that is recessed parallel to the upper surface. Similarly, the lower surface 9b of the piston 9 is tapered downward, and the inner surface of the lower lid portion 23 is also tapered so as to be recessed parallel thereto. FIG. 4A shows details of the upper surface 9a of the piston 9 of the present embodiment, and four spiral grooves 28 as turbulent flow forming means for forcibly making the cleaning liquid turbulent flow on the upper surface 9a. (The cross section is formed smoothly so as not to accumulate liquid wrinkles as shown in FIG. 2C). The spiral groove 28 becomes an uneven portion that forms a swirling flow of the cleaning liquid inside the cylinder 8, and may be formed on both or one of the inner surfaces of the upper lid portion 25 facing the upper surface 9a. Similarly, turbulent flow forming means such as a spiral groove 28 may be formed on the lower surface 9 b of the piston 9 and the inner surface of the lower lid portion 23.

  Such a turbulent flow forming means may be of any configuration as long as it can form a turbulent flow in the same manner as the spiral groove 28 in FIG. For example, as shown in FIG. 4B, the piston 9 may be rotatably provided together with the piston rod 10 to form a swirling flow by rotation. In this case, as shown by a chain line in FIG. 1, a motor 29 that rotates the piston rod 10 may be provided on the lower surface side of the horizontal plate 14 fixed to the ball nut body 13. Further, the connecting cylinder 25a provided on the upper lid portion 25 of the cylinder 8 is provided at a position eccentric from the central axis of the cylinder 8, and the flow of the cleaning liquid flowing into the cylinder 8 from the connecting cylinder 25a is eccentric from the central axis. It is good to form so that the turbulent flow of washing water may be formed.

  FIG. 5 shows the detailed contents of the upper lid portion 25 and the sealing member 27 of the cylinder 8.

  In the present embodiment, the cleaning liquid is applied to the inner end surface of the upper lid 25 provided at the axial end of the cylinder 8 facing the upper surface 9a of the piston 9 in the upper cleaning region Lb. An annular convex portion 30 is provided as a flow path changing means that advances toward the connecting portion. For example, as shown in FIG. 5, the annular convex portion 30 is formed in a triangular mountain shape in cross section, and the cleaning liquid flowing outward in the radial direction passes the sealing member 27 and the piston 9 at a position past the outer periphery of the piston 9. The flow direction is forcibly changed toward the connecting portion, and the connecting portion is washed with the cleaning liquid.

  Next, the operation of this embodiment will be described.

<Measurement of liquid> (see FIG. 1 and FIG. 2A)
As shown in FIG. 1, the liquid stored in the tank 5 opens the various partition valves and the like by pressurization of a feed pump (not shown) or the tank 5, and the piston type metering device 1 of the present embodiment through the flow path 6. Is set to be sent to

  First, the suction side valve 31 disposed in the flow path 6 laid between the tank 5 and the piston-type metering device 1 is opened, and the flow laid between the piston-type metering device 1 and the filling unit is opened. With the discharge side valve (not shown) disposed in the passage 7 closed, the ball screw 12 is rotated forward by the drive motor 16 to bring the piston 9 together with the ball nut body 13, the horizontal plate 14 and the piston rod 10 into the cylinder 8. The measuring region La is moved downward, and a required amount of liquid is sucked into the upper portion of the cylinder 8 through the flow path 6 and the connecting cylinder 25a of the upper lid portion 25. At this time, the piston 9 is in the measuring region La of the cylinder 8, and the sealing member 27 is always in close contact with the inner peripheral surface of the cylinder 8 by its own elasticity, so that the liquid can be sucked well.

  Subsequently, the suction side valve 31 disposed in the flow path 6 is closed, and the ball screw 12 is reversely rotated by the drive motor 16 with the unillustrated discharge side valve disposed in the flow path 7 opened. Along with the ball nut body 13, the horizontal plate 14 and the piston rod 10, the piston 9 is moved upward in the measuring area La of the cylinder 8, and a predetermined amount in the cylinder 8 is passed through the connecting cylinder 25 a of the upper lid portion 25 and the flow path 7. Drain the liquid. At this time, the piston 9 is in the measuring region La of the cylinder 8, and the sealing member 27 is always in close contact with the inner peripheral surface of the cylinder 8 by its own elasticity, so that the piston 9 moves upward by a predetermined length. Thus, a predetermined amount of liquid accurately measured can be discharged well.

  Also in the following explanation part, since the movement of the piston 9 in the axial direction is performed by the drive motor 16, the explanation of the drive system is omitted.

<Preparation before cleaning> (See FIGS. 2B and 2C)
Before starting cleaning, the piston 9 is raised to the upper cleaning region Lb as shown in FIG. 2 (b), or the piston 9 is moved to the lower cleaning region Lc as shown in FIG. 2 (c). The flow path 24 connected to the lower lid 23 is opened, and the drainage port (not shown) is opened, so that the liquid to be filled in the path of the tank 5, the flow paths 6, 7, etc. Discharge everything to the outside.

<Cleaning using the upper cleaning region Lb> (see FIGS. 2B and 3 to 5)
In the piston-type metering device 1 of the present embodiment, particularly when the upper surface 9a portion of the piston 9 and the large-diameter inner peripheral surface Sb of the cleaning region Lb on the upper side of the cylinder 8 and the vicinity thereof are mainly cleaned, As shown in FIGS. 2B and 3 to 5, the piston 9 is pushed up to the upper cleaning region Lb to open the flow path 24.

  Subsequently, the cleaning liquid filled in the tank 5 is fed into the cylinder 8 through the flow path 6 and the connecting cylinder 25a of the upper lid 25 at a considerable flow rate. The cleaning ability of the cleaning liquid may be appropriately adjusted by appropriately selecting the flow rate of the cleaning liquid, the pH of the cleaning liquid, the temperature of the cleaning liquid, and the like. The cleaning liquid may be supplied to the flow path 6 from a part other than the tank 5.

  The cleaning liquid fed between the upper surface 9a of the piston 9 and the inner end surface of the upper lid 25 flows from the central portion outward in the radial direction to clean both surfaces (typically 9a). At this time, as shown in FIG. 3, when the piston 9 is moved up and down in the axial direction, the cleaning liquid is vibrated between both surfaces (9a), and the both surfaces (9a) are more efficiently cleaned. At that time, the cleaning liquid discharged downward into the cylinder 8 by the water pressure and its own weight and hitting the upper surface 9a of the piston 9 becomes a direct flow that flows toward the inner peripheral surface Sb positioned around the cleaning liquid Lb. The cleaning effect of the inner peripheral surface Sb having a large diameter and the vicinity thereof can be enhanced. As shown in FIGS. 4 (a) and 4 (c), when a spiral groove 28 as a turbulent flow forming means is provided on at least one of both surfaces (9a), the turbulent flow is directed outwardly as a kind of turbulent flow. A wide swirling flow can be generated, and the cleaning efficiency can be further increased. As shown in FIG. 4B, when the motor 29 is operated and the piston 9 is rotated, the swirling flow of the cleaning liquid can be further strengthened, and the cleaning efficiency can be further increased. Further, as shown in FIG. 5, the cleaning liquid that has traveled radially outward between both surfaces (9 a) and has reached the annular convex portion 30 collides with the convex portion 30, and the flow direction changes between the sealing member 27 and the piston 9. The connecting portion is forcibly changed toward the narrow portion, and the connecting portion can be surely cleaned with the cleaning liquid. Furthermore, both peripheral surfaces (typically Sb) are surely secured by the cleaning liquid flowing at a high speed in a narrow portion between the large-diameter inner peripheral surface Sb of the upper cleaning area Lb of the cylinder 8 and the outer peripheral surface of the piston 9. To be washed. As described above, the flow rate of the cleaning liquid is increased or decreased by changing the cross-sectional area of the flow path formed between the cylinder 8 and the piston 9 in the upper cleaning region Lb and allowing the cleaning liquid to flow. Altered, efficient cleaning is performed. Furthermore, by moving the piston 9, the cross-sectional area of the flow path through which the cleaning liquid can flow can be appropriately changed.

  Also, the piston-type measuring device 1 is provided with an opening / closing means for the flow path 24, and the opening / closing of the opening / closing means is appropriately adjusted so that the piston 9 is moved up and down or rotated while the cylinder 8 is filled with the cleaning liquid. By doing so, you may wash | clean using sufficient washing | cleaning liquid.

  Moreover, it is good to perform the washing | cleaning which exhibits a synergistic effect combining the said various washing | cleaning methods in the upper washing | cleaning area | region Lb.

<Cleaning using the lower cleaning region Lc> (see FIG. 2C)
In the piston-type metering device 1 of the present embodiment, particularly when the lower surface 9b portion of the piston 9 is mainly cleaned, as shown in FIG. 2 (c), the piston 9 is lowered to the lower cleaning region Lc, The flow path 24 is left open.

  The cleaning liquid fed into the cylinder 8 reaches the upper surface 9 a portion of the piston 9, and then a narrow portion between the large-diameter inner peripheral surface Sc of the lower cleaning region Lc of the cylinder 8 and the outer peripheral surface of the piston 9. The two peripheral surfaces (typically Sc) are surely cleaned by flowing at a high speed. Thereafter, the cleaning liquid fed between the lower surface 9b of the piston 9 and the inner end surface of the lower lid 23 flows from the outer side in the radial direction toward the central portion to clean both surfaces (typically 9b). Further, as shown in FIGS. 4A and 4C, when a spiral groove 28 as a turbulent flow forming means is provided on at least one of both surfaces (9b), a swirling flow toward the central direction is applied to the cleaning water. Can be generated, and both surfaces (9b) can be efficiently cleaned. As described above, the flow rate of the cleaning liquid is increased or decreased by changing the cross-sectional area of the flow path formed between the cylinder 8 and the piston 9 in the lower cleaning region Lc and allowing the cleaning liquid to flow. Altered, efficient cleaning is performed.

  Alternatively, the piston-type metering device 1 may be provided with an opening / closing means for the flow path 24, and the cylinder 8 and the piston 9 used for liquid metering may be cleaned while appropriately adjusting the opening / closing of the opening / closing means. That is, the flow path 24 is closed by this opening / closing means, and the following cleaning may be performed with the cleaning liquid stored in the lower cleaning region Lc and the cylinder 8 above the upper surface 9a of the piston 9. .

  In this state, as shown in FIG. 3, when the piston 9 is moved up and down in the axial direction, the cleaning liquid is vibrated between both surfaces (9b), and the cleaning of both surfaces (9b) is performed more efficiently. Further, as shown in FIG. 4B, when the piston 29 is rotated by operating the motor 29, the swirl flow toward the center of the cleaning liquid can be further strengthened, and the cleaning efficiency can be further increased. it can.

  Further, as shown in FIGS. 4A and 4B, when a spiral groove 28 is formed on the upper surface 9a of the piston 9 and the piston 9 is rotated, the piston 9 is stored in the cylinder 8 above the upper surface 9a of the piston 9. It is possible to efficiently clean the entire inner surface Sc, Sa, Sb of the cylinder 8 according to the storage height of the cleaning liquid by turning the cleaning liquid that is being swung.

  Moreover, it is good to perform the washing | cleaning which exhibits a synergistic effect combining the said various washing | cleaning methods in the washing | cleaning area | region Lc of the lower part.

  Further, the cleaning liquid may be fed through the lower flow path 24.

  By performing such a cleaning process by appropriately changing the cleaning liquid, it is preferable to execute perfect cleaning of the inside of the piston type metering device 1 of the present embodiment.

  According to the piston-type metering device 1 of the present embodiment, the axially opposite end portions 9a and 9b of the piston 9 can be reliably cleaned using the cleaning regions Lb and Lc at both ends in the axial direction of the cylinder 8. The cylinder 8 and the piston 9 used for measuring the liquid can be cleaned in place automatically, easily and reliably without disassembling, improving the cleaning effect and increasing the amount of cleaning liquid. Reduction, shortening of working time, and cost reduction can be achieved. In particular, after measuring a liquid containing a solid substance or a liquid having a high viscosity, even if the solid substance or a liquid having a high viscosity adheres to the cylinder 8 or the piston 9, the liquid can be reliably removed.

  In addition, this invention is not limited to embodiment mentioned above, A various change can be made in the limit which does not impair the characteristic of this invention.

  For example, the cleaning state may be confirmed by inserting a small camera into the cylinder 8 through the lower flow path 24. In addition, a reagent capable of detecting the residue of proteins and other organic substances is circulated in the cylinder 8 and the reagent is taken out from the lower flow path 24 to investigate the presence or absence of proteins and other organic substances to confirm the quality of the washing. Good.

  Furthermore, it is preferable to circulate high-temperature air in the cylinder 8 to forcibly dry the inside of the apparatus and perform various treatments such as sterilization and sterilization.

DESCRIPTION OF SYMBOLS 1 Piston type measuring device 8 Cylinder 9 Piston 9a Piston upper surface 9b Piston lower surface 10 Piston rod La Measuring area | region Lb, Lc Cleaning area | region

Claims (7)

In a piston-type metering device that reciprocates a piston inserted from one axial end of a cylinder toward the other axial end of the cylinder and sucks and discharges liquid from the other end,
A measuring region in which the inner diameter of the inner peripheral surface for measuring the liquid in a sliding contact with the sealing member provided on the outer peripheral portion of the piston is fixed in the axially intermediate portion of the cylinder,
A piston-type metering device, wherein a cleaning region having a large-diameter inner peripheral surface spaced apart from the piston and the sealing member is formed continuously at both axial ends of the metering region of the cylinder. In a piston-type metering device that reciprocates a piston inserted from one axial end of a cylinder toward the other axial end of the cylinder and sucks and discharges liquid from the other end,
A large diameter separated from the piston and the sealing member is provided at the other axial end of the measuring area where the inner diameter of the inner peripheral surface for measuring liquid by sliding contact with the sealing member provided on the outer peripheral portion of the piston of the cylinder is constant. A piston-type metering device characterized in that a cleaning region having an inner peripheral surface is continuously formed. The cleaning liquid turbulent flow forming means is formed on at least one of the front end surface of the piston and the inner end surface on the other end side in the axial direction of the cylinder facing the piston. The piston type metering device as described. The piston-type metering device according to claim 3, wherein the turbulent flow forming means is formed by a concavo-convex portion that forms a swirling flow of the cleaning liquid inside the cylinder. The flow path changing means for advancing the cleaning liquid toward the sealing member in the cleaning region is provided on the inner end surface on the other axial end side of the cylinder. The piston type metering device according to any one of the above. The piston-type metering device according to any one of claims 1 to 5, wherein the piston is formed to be rotatable about a piston rod as a rotation center. The flow path for sucking and discharging the liquid and the cleaning liquid connected to the inner end face on the other axial end side of the cylinder is provided at a position eccentric from the central axis of the cylinder. The piston type metering device according to any one of claims 1 to 6.

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