JP3356308B2 - Gear metering pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear type metering pump which is preferably used when a resin fluid having a relatively high viscosity is pumped at a constant rate.

[0002]

2. Description of the Related Art A gear type metering pump is generally used to pump a relatively high-viscosity resin fluid such as a resin fluid that can be melted, a resin fluid dissolved using a solvent, and a resin fluid containing a monomer. Have been. The principle of the pumping is that the tooth space of two gears rotating while meshing with each other is filled with fluid at the inlet, and the fluid is confined between the tooth space and the casing according to the rotation of the gear, so that the fluid flows in the direction of the outlet on the circumference. , And are pushed out and discharged by the meshing of the gear teeth at the outlet.

[0003] A minute gap is provided between the side surface and the outer peripheral portion of the gear and the side surface of the pump casing, and lubrication is performed by the pumped liquid itself leaking from that portion. By minimizing the gap, leakage of the pumped liquid is minimized, and even if there is a pressure fluctuation or a viscosity change of the pumped liquid, quantitativeness can be secured with extremely high accuracy. That is,
The discharge amount is generally represented by the following equation.

Q = V _th · N−AΔP / μ Here, Q: discharge amount V _th : theoretical discharge amount per rotation N: number of rotations A: leakage flow coefficient determined from gap ΔP: outlet to inlet Pressure difference μ: viscosity of resin fluid By making the leak flow coefficient A as small as possible, high viscosity quantitative property can be obtained.

[0005] Therefore, in the conventional gear pump, the clearance between the side plate and the gear usually has an extremely small size of 2 to 5 µm on one side (4 to 10 µm on both sides), and the gap is slightly slid by the pumped liquid itself leaking from the portion. The liquid is sent while maintaining the volume efficiency extremely high while lubricating the moving parts.

[0006]

However, in the above gear pump, when a highly volatile resin solution or the like is fed, the solvent in the solution is volatilized on the gear side surface and the shaft portion, and the solution is solidified at that portion, and the gear pump is driven. Troubles such as rotation stop of the motor often occur. Therefore, a method to prevent solidification by enlarging the clearance on the side of the gear and providing a liquid discharge passage on the drive shaft to increase the amount of leaked pressure-feed liquid is conceivable.
Re that.

However, in this method, the liquid to be discharged is used as the lubricating liquid and discharged to the outside, so that the discharge amount per rotation is reduced, and the fluctuations in the supply pressure and discharge pressure of the liquid to the gear pump and the pressure supply liquid are also reduced. Fluctuation in the amount of leakage due to a change in viscosity causes an unstable discharge amount and adversely affects the product.

As another method, there is a method in which a liquid of the same type as the solvent of the solution is lubricated as a lubricating liquid from the outside and the liquid is used to lubricate the shaft and the gear side surface. However, it has the disadvantage of requiring a seal.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to realize a gear type metering pump having a simple structure and high stability of a discharge amount.

[0010]

In a gear type metering pump according to the present invention, a part of a fluid fed by the gear pump is supplied to a gear type metering pump which feeds liquid by a gear rotating while meshing with each other. A lubrication liquid has a flow path for supplying from a gear pump suction port to a gear side surface and / or a shaft portion, and the depth of a lubrication groove for lubricating the gear side surface is 50 μm or more, and the width of the lubrication groove is The length is from 20% to 60% of the length from the tooth bottom to the shaft.

Further, in the gear type metering pump of the present invention,
Uses a part of the fluid sent by the gear pump as lubrication
Supply at least to the gear side from the gear pump inlet
And a spiral flow path on the side of the gear. Also, the gear metering pump of the present invention
A part of the fluid sent by the gear pump is lubricated
From gear pump inlet to gear side and / or shaft
Has a passage for supplying, after lubrication, gear pump shaft a flow path for the lubricating liquid is discharged to the gear pump outside and or
Other has a side plate, further characterized in that the flow path for the lubricating liquid is discharged to the outside is provided for all gears. In addition, the clearance between the gear side surface and the side plate is 5 μm or less on one side. With this configuration, a gear type metering pump having a simple structure and high stability of the discharge amount can be obtained.

[0012]

According to the present invention, as shown in FIG. 2, a drive side gear 1 and a driven side gear 2 which rotate while meshing with each other are mounted on a drive shaft 3 and a driven shaft 4, respectively, and a side plate 5, 6 and a casing 7 are provided. The resin solution is sucked from the suction port 8 provided in the side plate 5 and has a small sliding clearance therebetween, and is sent to the discharge port 9 by pressure. Side plate 5,
6 is provided with a slit-shaped gear side lubrication groove 10 on both bearing sides of the gears 1 and 2, and a lubrication liquid supply channel 11 connecting the groove 10 and the suction port 8. It is supplied from the flow path to the gear side surface.

The lubricated liquid on both sides of the gear is immediately discharged from the lubricating liquid discharge passages 12 and 13 to the outside of the gear pump while lubricating the shaft. Therefore, there is no stagnation of the liquid in the sliding portion, and the solidification of the liquid in the sliding portion can be prevented by always lubricating with the new liquid. Moreover, since the liquid is supplied from the suction port of the gear pump, it is not necessary to increase the gap between the gear side surface and the side plate to use the liquid to be discharged for lubrication, and it is possible to secure a highly accurate discharge amount.

[0014]

1 and 2 are views showing an embodiment of the present invention. FIG. 1 is an exploded perspective view, and FIG. 2 is an assembled sectional view. In the present embodiment, as shown in FIG. 1, a driving gear 1, a driven gear 2, a driving shaft 3, a driven shaft 4, a side plate 5,
6 and a casing 7. The drive shaft 3 on which the drive-side gear 1 is mounted has a spiral lubricating fluid discharge channel 12 formed on the surface thereof and a lubricating fluid discharge port 1 formed in the center.
The driven shaft 4 fixed to the side plate 5 is provided with a lubricating fluid discharge channel 13.

The side plate 5 has an inlet 8
, Discharge port 9, gear side surface lubrication groove 10,
And a lubricating liquid supply flow path 11 that connects between the suction port 8. The side plate 6 has a lubricating liquid discharge port 15,
Gear side lubrication groove 10 (not shown) similar to side plate 5
And a lubricating liquid supply path 11 are provided. The casing has a cocoon-shaped space in which the drive gear 1 and the driven gear 2 can rotate while meshing with each other. The members thus formed are assembled as shown in FIG.

In this embodiment constructed as described above, when the drive shaft 3 is rotated, the drive gear 1 and the driven gear 2 mesh with each other and rotate in the casing. The pressure is fed to the discharge port 9 to discharge. At the same time, the resin solution is supplied from the suction port 8 to the lubrication groove 10 through the lubrication liquid supply channel 11 to lubricate the side surfaces of the drive gear 1 and the driven gear 2. The lubricated resin solution passes through the lubricating fluid discharge channel 12 of the drive shaft 3 from the lubricating fluid discharge port 14, and passes through the driven shaft 4 and the lubricating fluid discharge channel 13 of the side plate 6 to form the lubricating fluid outlet 15. From the pump immediately.

Thus, there is no stagnation of the liquid in the sliding portion.
By always being lubricated with a new liquid, solidification of the liquid at the sliding portion can be prevented. Further, since the liquid is supplied from the suction port of the gear pump, it is not necessary to increase the gap between the gear side surface and the side plate and use the liquid to be discharged for lubrication, and it is possible to secure a highly accurate discharge amount.

Further, it is desirable that the width of the gear side surface lubrication groove 10 be large in order to lubricate the gear side surface. However, if this width is too large, the distance between the tooth bottom and the lubrication groove will be short,
The liquid to be discharged easily leaks into the lubrication groove, and as a result, a highly accurate discharge amount cannot be secured. Conversely, if the width of the lubrication groove is too narrow, lubrication of the gear side surface will be insufficient, and the gear side surface will tend to seize and solidify the liquid. If the depth of the lubrication groove is too shallow, the lubricating liquid will not flow easily, and a new lubricating liquid will not be supplied. Troubles such as stoppage are likely to occur.

[0019] Thus preferably 5μm or less on one side for the clearance of the gear surface side (h) is to ensure the quantitative properties of the gear pump is a gear pump of the present invention, also scan <br/> slit-shaped gear as shown in FIG. 3 The side lubrication groove 10 has a clearance (t) of 5
The width (m) is set to 20 to 60% of the distance (l) from the tooth bottoms of the gears 1 and 2 to the shaft. Clearance (h)
Is lubricated by a small amount of pressure-feeding liquid, and the lubricated liquid is discharged to the outside of the gear pump through the shaft part while leaking little by little into the lubricating liquid flowing through the gear side lubrication groove. In the gear pump of the present invention, since the lubricating liquid is sent by the liquid pressure applied to the suction port of the gear pump, it is necessary to set the pressure of the supply liquid to the suction port higher than the lubricating liquid flow path pressure loss.

The resin fluid that can be used in the method of the present invention is shown below. A mixed system of a resin of Group A and a monomer of Group B may be mentioned, but is not limited to those listed here. Further, a small amount of a photopolymerization initiator or a thermal polymerization initiator can be contained. Group A: polycarbonate, polystyrene, polymethyl methacrylate, polymethyl acrylate, ethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride, polyvinyl fluoride, etc. Group B: methyl methacrylate, ethyl methacrylate, vinyl chloride , Vinyl acetate, vinyl fluoride, acetone, etc.

Hereinafter, the present invention will be further described with reference to practical examples. Practical example 1 Rated 0.15 cc / rev of the structure as shown in FIG. 1 and FIG.
Using a gear-type metering pump, using polymethyl methacrylate as the polymer as the liquid to be pumped and methyl methacrylate and fluorinated methacrylate as the monomers, each having a weight ratio of 45: 3.
Using the resin solution mixed and stirred at a ratio of 5:20, the resin supply pressure to the gear pump was set to 5 kg / cm ² , and the gear-type metering pump was driven at three revolutions per minute to drive the resin solution from the nozzle for 1 m. Per minute. Irradiation with actinic light was carried out immediately before the withdrawal to complete polymerization and solidification to form a filament, and the outer diameter and discharge pressure of the filament were measured.

In the gear type metering pump having the lubrication groove dimensions as shown in Experiment Nos. 1, 2, 3 and 4 in Table 1, troubles of stopping the gear pump due to solidification of the solution did not occur, and the discharge pressure and the outer diameter of the filament did not increase. Fluctuation was able to be performed stably with little change.

[0023]

[Table 1]

COMPARATIVE EXAMPLE 1 A conventional 0.15 cc / rev gear-type metering pump having no lubricating fluid supply passage to the sliding portion as shown in FIG. Using methyl methacrylate and fluorinated methacrylate as monomers and mixing them in a weight ratio of 45:35:20, respectively.
Using the agitated resin solution, the resin supply pressure to the gear pump was set to 5 kg / cm ² , and the gear-type metering pump was driven at three revolutions per minute to discharge the resin solution from the nozzle at 1 m / cm.
Withdrawn at a rate of minutes. Irradiate with actinic rays just before picking up,
The polymer was completely polymerized and solidified to form a filament, and the outer diameter and discharge pressure of the filament were measured.

In conventional gear pumps having gear side clearances as shown in Experiment Nos. 1, 2, 3 and 4 in Table 2, a trouble in stopping the gear pump occurred when the gear side clearances were small. When the clearance on the gear side was increased, the trouble of stopping the gear pump did not occur, but the discharge pressure and the outer diameter of the filament became large, and stable liquid supply was not possible.

[0026]

[Table 2]

Comparative Example 2 A rated 0.15 cc / rev gear-type metering pump having a structure as shown in FIG. 4 was used, and polymethyl methacrylate was used as a pumping liquid, and methyl methacrylate and fluorinated methacrylate were used as monomers. 45:35:20 by weight
Using a resin solution mixed and stirred at a rate of 1 g, the resin supply pressure to the gear pump was set to 5 kg / cm ² , and the gear type metering pump was driven at three revolutions per minute to discharge the resin solution from the nozzle at 1 m / min. Picked up at speed. Irradiation with actinic light was carried out just before being picked up to complete polymerization and solidification to form a filament, and the outer diameter and discharge pressure of the filament were measured.

In the gear type metering pump having the lubrication groove dimensions as shown in Experiment Nos. 1, 2, 3, 4 and 5 in Table 3, gear stop troubles and fluctuations in discharge pressure and filament outer diameter occur, resulting in stable operation. Liquid cannot be sent.

[0029]

[Table 3]

[0030]

As described in detail above, the present invention secures high quantitativeness and prevents solidification at the sliding portion, thereby making it possible to obtain a high precision dimensional stability for films and filaments. It has the advantage of enabling high quality and stable operation.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

2A and 2B are diagrams showing an embodiment of the present invention, wherein FIG. 2A is a cross-sectional view taken along the line aa of FIG. 2B, and FIG.
It is sectional drawing in a line.

3A and 3B are diagrams for explaining dimensions of a lubricating liquid flow channel according to an embodiment of the present invention, wherein FIG. 3A is a cross-sectional view taken along line aa of FIG. 3B, and FIG. It is sectional drawing in the bb line.

FIG. 4 is a schematic view showing a conventional gear type metering pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Drive side gear 2 ... Driven side gear 3 ... Drive shaft 4 ... Driven shaft 5, 6 ... Side plate 7 ... Casing 8 ... Suction port 9 ... Discharge port 10 ... Lubrication groove 11 ... Lubricating liquid supply flow path 12, 13 ... Lubricating fluid discharge channel 14, 15 ... Lubricating fluid outlet

Continuation of the front page (56) References JP 5-21192 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04C 2/18 F04C 15/04

Claims (5)

(57) [Claims] 1. A gear type metering pump for feeding liquid by gears rotating while meshing with each other, wherein a part of the fluid fed by the gear pump is supplied as lubricating liquid from a gear pump inlet to a gear side surface and / or a shaft portion. And the depth of the lubrication groove for lubricating the side surface of the gear is 50 μm or more, and the width of the lubrication groove is 20% or more and 60% or less of the length from the gear tooth bottom to the shaft portion. A gear metering pump characterized in that: 2. A gear metering pump for feeding liquid by gears rotating while meshing with each other, wherein a flow for supplying a part of the fluid sent by the gear pump as a lubricating liquid from a gear pump suction port to at least a side surface of the gear. A gear type metering pump characterized in that it has a path and the flow path on the side of the gear is spiral. 3. A gear type metering pump which feeds liquid by gears rotating while meshing with each other, wherein a part of the fluid fed by said gear pump is supplied as lubricating liquid from a gear pump suction port to a gear side surface and / or a shaft portion. After the lubrication, the lubrication liquid has a flow path for discharging to the outside of the gear pump on the gear pump shaft and / or the side plate. A gear type metering pump characterized by being provided for a gear. 4. A lubricating after gear-type metering pump according to claim 1 or 2 lubricating liquid is characterized by having the gear pump shaft and or the side plate a passage for discharged into gear pump outside. 5. The apparatus according to claim 1 , wherein the clearance between the side surface of the gear and the side plate is 5 μm or less on one side.
3. The gear type metering pump according to any one of the items up to 3 .