JP7833766B2 - Weighing device - Google Patents

Description

This invention relates to a measuring device having a cylinder and a piston that reciprocates within the cylinder, and having a configuration that can prevent sliding failures between the cylinder and the piston caused by the solidification of the filling liquid or other material to be measured.

Conventionally, when filling containers with high-viscosity liquids at high speed and pressure with high metering accuracy, filling devices equipped with a piston-type metering device that houses the liquid in a piston cylinder and measures the filling amount by the movement of the piston have been used. The piston-type metering device is configured to discharge the liquid, such as the filling liquid supplied to the cylinder, into the filling device by sliding a piston, which is sealed in a gap with the cylinder by a packing.

However, when measuring and filling liquids containing sugar, the sugar and other substances could sometimes adhere to the sliding surface between the piston and cylinder, hindering the piston's movement.

Therefore, as shown in Figure 4, in a metering device 1 that reciprocates a piston 2 inserted from an open portion at one axial end of a cylinder 3 toward the other axial end of the cylinder 3 to draw in and discharge liquid from that end, a method was employed to prevent sticking, which would hinder the sliding of the piston 2, by connecting a tube 21 to the back side of the piston 2 and routing it to supply water to the sliding portion between the piston 2 and the cylinder 4 that is outside the packing 4, thereby preventing sliding failure (the reference numerals in Figure 4 correspond to the reference numerals in this embodiment).

In liquid filling processes for food, pharmaceuticals, and other products, especially in high-mix, low-volume production, pre- and post-filling processes, as well as regular cleaning and sterilization, are essential. Furthermore, piston-type weighing devices, due to the difficulty of cleaning the area between the piston and cylinder, required manual disassembly, cleaning, and reassembly after each use.

However, manual disassembly, cleaning, and reassembly were time-consuming, significantly reducing productivity, increasing costs, and carrying the risk of damage due to operational errors.

Therefore, in recent years, a cleaning method called "CIP (Cleaning In Place) cleaning," which automatically cleans the device by flowing cleaning fluid into its interior without disassembling it, has been adopted. The applicant has also developed a piston-type metering device compatible with CIP cleaning (see Patent Document 1).

Japanese Patent Publication No. 2013-060226

However, in piston-type metering devices designed for CIP (Clean-in-Place) cleaning, the back of the piston is also cleaned. The back of the piston is located within a closed cylinder, covered, and not exposed. Therefore, the conventional method for preventing sliding failures, as shown in Figure 4, could not be adopted.

This invention has been made in view of the above problems, and aims to provide a CIP-cleanable measuring device with a configuration that can prevent poor sliding between the cylinder and piston caused by the solidification of the filling liquid to be measured.

To achieve the aforementioned objective, a metering device according to a first aspect of the present invention is a metering device having a piston having a head portion that slides against the inner wall of a cylinder via a sealing member and a rod portion connected to the head portion, the rod portion of which is extended toward one axial end of the cylinder, the head portion is reciprocated toward the other axial end of the cylinder, and the liquid to be measured or cleaning liquid is to be sucked in and out from the other axial end of the cylinder,
The cylinder has a measuring region in its axial middle portion, where the inner diameter of the inner surface is constant and the liquid is measured by sliding against a sealing member provided on the outer peripheral edge of the piston. A cleaning region with a large-diameter inner surface spaced apart from the piston and sealing member is continuously formed at at least one axial end of the measuring region of the cylinder. Furthermore, a discharge section is formed at one axial end of the cylinder to discharge any remaining liquid inside the cylinder.
The head portion has a head portion water supply channel formed between an upstream water supply end disposed within the head portion of the cylinder and a downstream water supply end that opens on the side facing the inner wall of the cylinder, on the side facing the sealing member, towards one end in the axial direction of the cylinder.
The rod portion is hollow and tubular, with one end connected to the upstream end of the water supply in the head portion to form a water supply channel for the rod portion, and the other end of the rod portion is connected to a water channel for a water supply device for an anti-sticking fluid so as to be able to move in accordance with the reciprocating motion of the piston.
The system is characterized by enabling CIP cleaning by supplying cleaning fluid into the cylinder while reciprocating the piston in the metering area and the cleaning area, and discharging the cleaning fluid used for cleaning from the discharge section .

With the metering device configured in this way, the anti-sticking liquid supplied from the water supply device is passed through the water supply channel of the rod section and the water supply channel of the head section and supplied to the downstream end of the water supply, which opens on the side of the head section facing the inner wall of the cylinder. In this state, the head section is reciprocated within the cylinder, and the anti-sticking liquid supplied to the downstream end of the water supply is applied between the inner wall of the cylinder and the piston by a sealing member, thereby suppressing the solidification of the liquid to be metered and preventing piston sliding failure. Furthermore, since the water channel for the anti-sticking liquid supplied to suppress the solidification of the liquid to be metered is not exposed inside the shaft, CIP cleaning becomes possible.

Furthermore, the weighing device according to the second aspect of the present invention is characterized in that the head portion comprises a piston head on which the sealing member is provided on the outer peripheral edge , and a piston base on which the piston head is fixed to one side and the rod portion is connected to the other side, and a water supply channel for the head portion is formed in the piston base.

With this configuration, the anti-sticking liquid supplied from the water supply device can be supplied from the rod section's water supply channel through the head section's water supply channel formed in the piston base to the downstream end of the water supply, which opens on the side of the head section facing the inner wall of the cylinder. Furthermore, since the water channel for the anti-sticking liquid supplied to prevent the liquid being measured from sticking is not exposed inside the shaft, it does not hinder the reciprocating motion of the piston, nor does it cause problems such as the water channel tube coming loose.

As described above, the measuring device of the present invention can prevent poor sliding between the cylinder and piston caused by the solidification of the filling liquid being measured, and can also be configured for CIP (Cleaning by Intake and Precipitation) cleaning.

Cross-sectional view of the main components of one embodiment of the weighing device of the present invention Cross-sectional view of the main components of the piston head in the measuring device shown in Figure 1. Figure 2 is a plan view showing the water supply channel at the piston head of the metering device, illustrating the state without water (A) and the state with water (B). Cross-sectional view of the main components of one embodiment of a conventional weighing device.

The embodiments of the weighing device of the present invention will be described below with reference to Figures 1 to 3.

As shown in Figure 1, the piston 2 of the weighing device 1 in this embodiment has a head portion 5 that slides against the inner wall of a cylinder 3, which is arranged with its axial direction vertical, and a rod portion 6 that extends outward from one axial end (lower end) of the cylinder 3 and is reciprocated within the cylinder 3 by a piston drive mechanism (not shown). The head portion 5 is fixed to one end (upper end) of the rod portion 6, and by reciprocating the rod portion 6 within the cylinder 3 by a known piston drive mechanism, the packing 4, which serves as the sealing member 4 disposed on the head portion 5, is made to slide against the inner wall of the cylinder 3.

Here, as shown in Figure 2, the head portion 5 has a head portion water supply channel 7 connecting the upstream water supply end P1 formed within the head portion 5 and the downstream water supply end P2 which is opened on the side facing the inner wall of the cylinder 3. More specifically, the head portion 5 has a piston head 8 with a packing 4 on its outer peripheral edge, and a piston base 9 to which a rod portion 6 is connected on one side (bottom surface) and to which the piston head 8 is fixed on the other side (top surface).

In this embodiment, the piston base 9 is substantially disc-shaped, and as shown in Figures 3(A) and 3(B), a hole 10, which serves as the upstream water supply end P1, is drilled in the center. From this hole 10, the head section water supply channels 7 are formed in all directions, extending toward the sides of the piston base 9. In other words, the opening on the side of the head section water supply channel 7 facing the inner wall of the cylinder 3 becomes the downstream water supply end P2.

Furthermore, the rod section 6 is hollow and tubular, with one end (upper end) connected to the center of the lower surface of the piston base 9. This connects the upstream water supply end P1 to the inside of the hollow pipe, forming the rod section water supply channel 11.

Returning to the description of the piston head 8, an annular rim 12 is formed around the outer periphery of the upper surface of the piston base 9, rising in a levee-like shape. The rim 12 is formed by bulging its outer circumferential wall towards the inner wall of the cylinder 3 compared to the outer periphery of the other side of the piston base 9.

The piston head 8 is then fixed to the upper surface of the piston base 9 by a pin-shaped fastener 13 inserted from the lower side of the piston base 9, with the piston head 8 seated on the one-sided surface and edge 12.

In detail, as shown in Figure 1, the piston head 8 is formed in three stages, concentrically increasing in diameter from the piston base 9 side. The first stage 8a, which is on the piston base 9 side, is placed on the upper surface of the piston base 9. The stepped portion 8d between the first stage 8a and the second stage 8b is fitted onto the edge 12 of the piston base 9. A packing 4 is sandwiched between the stepped portion 8e between the second stage 8b and the third stage 8c and the edge 12 of the piston base 9, and the piston head 8 is fixed by a fixing device 13.

Therefore, the flow of water through the head section's water supply channel 7 is restricted by blocking the upper part of the hole 10 drilled in the center of the piston base 9, which constitutes the upstream end P1 of the water supply, with the first stage 8a of the piston head 8. The upper surface of the piston head 8 is slightly tapered upwards.

Furthermore, as will be described later, a piston drive mechanism (not shown) of a known configuration is connected to the other end of the rod portion 6 that protrudes from the lower end of the cylinder 3. In addition, a tube 21 forming a water channel for a water supply device (not shown) for anti-sticking fluid is connected via a joint 22, so as to follow the piston 2 reciprocating within the cylinder 3 by this piston drive mechanism.

Furthermore, in this embodiment, the cylinder 3 is configured such that a cleaning area 3b, with a large-diameter inner circumferential surface spaced apart from the piston head 8 and packing 4, is continuously formed at the axial upper end of the metering area 3a.

In other words, the cylinder 3 is formed with a bottom, and inside the cylinder 3, there is a measuring region 3a with a constant inner diameter on the inner surface that slides against the packing 4 provided on the outer circumference of the piston 2 to measure the filling liquid. At the axial upper end of this measuring region 3a of the cylinder 3, there are continuous cleaning regions 3b and 3c, which have large-diameter inner surfaces spaced apart from the piston 2 and packing 4.

In these cleaning regions 3b and 3c, a large-diameter inner surface is formed over the axial length that accommodates the entire piston head 8. This large-diameter inner surface is formed by a tapered portion 3d, which constitutes the cleaning region 3b and gradually increases in diameter upward from the upper end of the inner surface of the metering region 3a, where the inner diameter is constant; and a large-diameter portion 3e, which constitutes the cleaning region 3e and has the largest inner diameter of the tapered portion 3b.

The upper end of the cylinder 3 is closed by the upper lid 14, and a packing (not shown) is interposed between the two to ensure a seal. A connecting cylinder 15, for connecting to a liquid supply passage and a liquid drain passage (not shown), protrudes upward from the central axis of the upper lid 14.

On the other hand, the rod portion 6 of the piston 2 is positioned at the bottom of the cylinder 3, which is the lower end of the cylinder, and is sealed by a sealing member (not shown) while passing through this bottom. Furthermore, a discharge portion (not shown) for discharging residual fluid from the cylinder 3 is formed at a position away from the point where the rod portion 6 of the piston 2 passes through the bottom.

Next, the operation of the weighing device of this embodiment will be explained.
The filling liquid stored in a tank (not shown) is supplied to the measuring device 1 of this embodiment through the liquid supply passage connected to the connecting cylinder 15 by pressurizing the supply pump (not shown) and the tank (not shown), which opens various valves (not shown), and sets the device to a state where a fixed amount can be measured.

Specifically, the suction valve (not shown) located in the liquid supply passage laid between the tank and the measuring device 1 is opened, and the discharge valve (not shown) located in the liquid drain passage laid between the measuring device 1 and the filling section is closed. With these settings, the piston drive mechanism is driven, moving the piston 2 downwards in the measuring area 3a of the cylinder 3. This draws the required amount of liquid from the liquid supply passage through the connecting cylinder 25a into the upper part of the cylinder 3. At this time, the piston 2 is located in the measuring area 3a of the cylinder 3, and the packing 4 is constantly in close contact with the inner surface of the cylinder 3 due to its own elasticity, ensuring efficient liquid suction.

Next, with the suction valve located in the liquid supply passage closed and the discharge valve located in the drain passage opened, the piston drive mechanism is driven, moving the piston 2 upward in the metering region 3aa of the cylinder 3, thereby discharging a predetermined amount of liquid from the cylinder 3 through the drain passage via the connecting cylinder 25a. At this time, the piston 2 is located in the metering region 3a of the cylinder 3, and the packing 4 is constantly in close contact with the inner circumferential surface of the cylinder 3 due to its own elasticity. Therefore, by moving the piston 2 upward by a predetermined length, a precisely measured predetermined amount of liquid can be discharged efficiently.

Furthermore, in the measuring device 1 of this embodiment, while the measuring device 1 is operating, an anti-sticking liquid supplied from the water supply device (not shown) is supplied from the tube 21, which is connected to the lower end of the rod portion 6 via a joint 22, to the rod portion water supply channel 11 formed inside the rod 6.

The anti-sticking liquid used in this process should be selected appropriately based on its relationship to the liquid being measured. For example, water can often be used for general food and beverages. The supply volume should be adjusted as needed by the water supply system.

The anti-sticking fluid supplied from the water supply device is supplied from the rod section water supply channel 11 through the head section water supply channel 7, as shown in black in Figure 3(B), to the downstream water supply ends P2 that open below the packing 4 at four locations on the side of the head section 5.

In this state, when the head unit 5 is reciprocated within the cylinder 3, the anti-sticking liquid supplied to the downstream end P2 of the water supply is applied between the inner wall of the cylinder 3 and the piston 2 by the packing 4. In this way, the anti-sticking liquid is applied to the inner wall of the cylinder 3 as a preventative measure against the solidification of the liquid being measured. Furthermore, by using a small amount of the anti-sticking liquid and the packing 4 to scrape off any liquid that remains on the inner wall of the cylinder 3 and is prone to solidification, the solidification of the liquid being measured can be suppressed.

Furthermore, since the anti-sticking fluid is supplied to the downstream water supply end P2, which opens below the packing 4, the packing 4 can prevent the anti-sticking fluid from mixing with the liquid being measured, which accumulates above the piston head 8 inside the cylinder 3.

Excess anti-sticking fluid, as well as residue and remaining fluid scraped off by the packing 4 along with the anti-sticking fluid, are collected at the bottom of the cylinder 3 and discharged as waste liquid through the discharge section (not shown) that removes the remaining fluid from the cylinder 3.

Furthermore, the weighing device of this embodiment also allows for CIP (Clean-in-Place) cleaning. A brief explanation follows below.
Before starting the cleaning process, the piston 2 is raised to the upper cleaning areas 3b and 3c, and all the liquid in the metering channels, such as the tank 5, supply channel 6, the aforementioned drain channel, and cylinder 3, is discharged to the outside through the drain port (not shown).

In the metering device 1 of this embodiment, when cleaning the piston 2, the piston 2 is pushed up into the cleaning areas 3b and 3c, and the supply passage 24 is opened. Subsequently, the cleaning liquid filled in the tank (not shown) is supplied to the cylinder 3 through the supply passage 6 and connecting cylinder 25a at a considerable flow rate. The cleaning capacity of this cleaning liquid should be appropriately adjusted by selecting the flow rate, pH, and temperature of the cleaning liquid as appropriate.

The cleaning fluid supplied between the upper surface of the piston 2 and the inner end surface of the upper lid 14 flows radially outward from the center. When the piston 2 is moved axially up and down within the cleaning region 3b, the cleaning fluid is vibrated, efficiently cleaning both sides of the piston 2. In this way, by significantly increasing or decreasing the cross-sectional area of the flow path formed between the cylinder 3 and the piston 2 in cleaning regions 3b and 3c, the flow velocity of the cleaning fluid is varied, enabling efficient cleaning of the piston 2 and, furthermore, cleaning of the inside of the cylinder 3 using the cleaning fluid.

Furthermore, cleaning the inside of the cylinder 3 can be performed by making the inner wall of the cylinder 3 and the packing 4 slide against each other while the piston 2 is moved back and forth in a large range within the metering area 3a. Similarly, cleaning the drainage passage can be performed by moving the piston 2 back and forth, just as during drainage, and discharging the cleaning fluid through the drainage passage.

Thus, during CIP cleaning, the measuring device 1 of this embodiment does not expose the water channel for the anti-sticking liquid supplied to prevent the liquid being measured from solidifying inside the shaft. Therefore, it does not hinder the reciprocating motion of the piston 2, nor does it cause problems such as the detachment of the water channel tube.

Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made without impairing the features of the present invention.

For example, in this embodiment, the head section water supply channels 7 are formed extending in all directions from the hole that serves as the upstream end P1 of the water supply, but the number of head section water supply channels 7 is not limited to this number. The configuration of the cylinder 3 capable of CIP cleaning is also not limited to the configuration described above; for example, the cleaning area 3b of the piston 2 may be provided not only above the metering area 3a of the cylinder 3, but also below it.

The measuring device 1 of the present invention can be used as the measuring device in a filling device that is configured to draw a liquid to be filled from a tank through a flow path into the cylinder 3 of the measuring device, and then fill a predetermined amount of the liquid to be filled from the cylinder 3 through the flow path into a filling section and into a filling container.

With a filling device configured in this way, it is possible to prevent poor sliding between the cylinder 3 and the piston 2 caused by the solidification of the filling liquid being measured, and consequently, to prevent filling defects.

1. Measuring device 2. Piston 3. Cylinder 3a. Measuring area 3b, 3c. Cleaning area 3d. Tapered section 3e. Large diameter section 4. Sealing member (packing)
5 Head section 6 Rod section 7 Head section water supply channel P1 Upstream water supply end P2 Downstream water supply end 8 Piston head 8a First stage 8b Second stage 8c Third stage 8b Step (between the first and second stages) 8e Step (between the second and third stages) 9 Piston base 10 Hole 11 Rod section water supply channel 12 Edge 13 Fixing device 14 Top cover 15 Connecting cylinder 21 Tube 22 Fitting

Claims (2)

A metering device having a piston having a head portion that slides against the inner wall of a cylinder via a sealing member and a rod portion connected to the head portion, the rod portion of which extends toward one axial end of the cylinder, the head portion reciprocates toward the other axial end of the cylinder, and the device is capable of sucking in and discharging a liquid to be measured or a cleaning liquid from the other axial end of the cylinder,
The cylinder has a measuring region in its axial middle portion, where the inner diameter of the inner surface is constant and the liquid is measured by sliding against a sealing member provided on the outer peripheral edge of the piston. A cleaning region with a large-diameter inner surface spaced apart from the piston and sealing member is continuously formed at at least one axial end of the measuring region of the cylinder. Furthermore, a discharge section is formed at one axial end of the cylinder to discharge any remaining liquid inside the cylinder.
The head portion has a head portion water supply channel formed between an upstream water supply end disposed within the head portion of the cylinder and a downstream water supply end that opens on the side facing the inner wall of the cylinder, on the side facing the sealing member, towards one end in the axial direction of the cylinder.
The rod portion is hollow and tubular, with one end connected to the upstream end of the water supply in the head portion to form a water supply channel for the rod portion, and the other end of the rod portion is connected to a water channel for a water supply device for an anti-sticking fluid so as to be able to move in accordance with the reciprocating motion of the piston.
A metering device characterized in that it enables CIP cleaning by supplying cleaning fluid into the cylinder, reciprocating the piston in the metering area and the cleaning area, and discharging the cleaning fluid used for cleaning from the discharge section . The metering device according to claim 1, wherein the head portion comprises a piston head on which the sealing member is provided on the outer peripheral edge , and a piston base on which the piston head is fixed to one side and the rod portion is connected to the other side, and the piston base is provided with a water supply channel for the head portion.