WO2006090495A1

WO2006090495A1 - Gear pump

Info

Publication number: WO2006090495A1
Application number: PCT/JP2005/015675
Authority: WO
Inventors: Motohiro Okada
Original assignee: Shimadzu Corporation
Priority date: 2005-02-24
Filing date: 2005-08-29
Publication date: 2006-08-31
Also published as: CN101133250A; JPWO2006090495A1; CN100513789C; US20090060770A1; KR20070112211A; JP4688864B2; TW200634233A; JPWO2006090652A1; TWI294945B

Abstract

A gear pump that is more suitable for sending high-pressure, high-viscosity fluid such as melted resin. A gear pump (100) for sending fluid from the suction opening (11) side to the discharge opening (12) side by rotation of a pair of gears (2, 3) provided in a casing (1) and meshing with each other. The gears (2, 3) are double-helical gears having a one point continuous contact tooth profile, and for both gears (2, 3), a ratio D/B, or a ratio of a gear outer diameter D to a tooth width B, is set to in the range of 1.1 - 1.15. When D/B is below 1.1, a bearing load is excessive and the bearings may be damaged, causing the gears to be unsuitable for forcing of melted resin, etc. On the other hand, when D/B is above 1.15, the outer profile of the pump is larger and mechanical efficiency is reduced to lower the entire efficiency.

Description

Specification

Gear pump

Technical field

[0001] The present invention relates to a gear pump used for transferring a high-pressure, high-viscosity fluid.

Background art

[0002] There are very many gear pumps that employ an involute tooth profile to transfer fluid from the suction side to the discharge side by rotation of the meshing gear. This is because the involute tooth profile is easy to cut and the finish dimension of the tooth profile is easy to measure, so a high-precision gear can be obtained, and therefore it can be adapted to high-pressure operating conditions.

Patent Document 1: Japanese Patent Laid-Open No. 11-013642

Disclosure of the invention

Problems to be solved by the invention

[0003] A problem of a gear pump employing an involute tooth profile is a fluid confinement phenomenon. The intermittency ratio of involute gears is typically greater than 1, and there is a period during which two sets of teeth are engaged. In that case, the force by which the fluid is confined between these two sets of teeth. The volume of this confinement region varies with the rotation of the gears. Troubles such as the generation of vacuum or bubbles are detected. However, the harm of the confinement phenomenon is much greater during compression than during expansion.

[0004] The harm of the above-described confinement phenomenon becomes more prominent as the viscosity, suction pressure, and discharge pressure of the fluid to be transferred are higher. In particular, in applications where molten resin is pumped, a high temperature of about 300 ° C, high pressure of about 20MPaG, and high viscosity of about 300Pa's are transferred. This shortens the bearing life. Currently, this is dealt with by improving the bearing, or by giving a margin to the bearing specifications (for example, increasing the shaft diameter, decreasing the rotational speed, etc.). Invited to increase. [0005] The present invention made in view of the above is intended to realize a gear pump suitable for transferring a high-pressure, high-viscosity fluid such as a high molecular weight polymer or a molten resin.

Means for solving the problem

[0006] A gear pump of the present invention that solves the above-described problems is provided with a casing having a suction port through which a fluid is introduced and a discharge port through which the fluid is discharged, and provided in the casing, and meshing with each other. And a pair of gears that transfer the fluid from the suction port to the discharge port by rotation, and the pair of gears is a single-point continuous contact tooth-shaped helical gear, and the outer diameter of each of the gears The specific force between the teeth and the tooth width is 1.1 to 1.15.

[0007] That is, a tooth profile such as an arc tooth profile, an elliptical tooth profile, or a sinusoidal tooth profile that always has one contact point and does not cause fluid confinement is used, and the axial thrust is balanced as a spur gear, Axial thrust is avoided from acting on the gear. In addition, by setting DZB to 1.1 to 1.15, efficiency is secured while suppressing bearing load. If DZB is less than 1.1, the bearing load may be excessive and damage to the bearing may occur, making it unsuitable for applications such as feeding molten resin. On the other hand, if DZB exceeds 1.15, the work force that can be used for the pump size increases. Since power loss due to friction between the gear and the casing increases rapidly as the outer diameter of the gear increases, increasing the outer diameter to reduce the tooth width for a given discharge rate increases the mechanical efficiency as the pump outer diameter increases. Directly leading to a decrease in overall efficiency. For these reasons, it is desirable that D / B be 1.1 to 1.15.

The invention's effect

[0008] According to the present invention, it is possible to realize a gear pump suitable for transferring a high-pressure, high-viscosity fluid such as a polymer or a melted resin.

Brief Description of Drawings

FIG. 1 is a plan sectional view showing a gear pump according to an embodiment of the present invention.

FIG. 2 is a side sectional view of the gear pump shown in FIG.

FIG. 3 is a flow chart showing the production process of a molded article of a high molecular weight polymer to which the gear pump of the present invention is applied.

Explanation of symbols [0010] 1 ... Casing

2, 3 ... Gear

100 ... Gear pump

200 ... Polymerizer

300 ... Molding equipment

400 ... Spinning equipment

D ... Gear outer diameter

B ... tooth width

E… Two positions where the tooth tips of both rotating gears are separated from the inner peripheral surface of the casing,

Three

Angle between line segments connecting pitch points

E: Positional force where the tooth tip of the rotating gear is in close proximity to the inner peripheral surface of the casing.

Four

Arc angle until the tip of the tooth is separated from its inner peripheral surface force

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Example

[0012] The gear pump 100 of the present embodiment shown in Figs. 1 and 2 is a high-priced material such as a molten resin or other high molecular weight polymer in a petroleum plant, a chemical plant, a polymerization plant, a molding and spinning device, or the like. Used to pump viscous material at high pressure. These highly viscous materials may be intermediates or final products. The gear pump 100 is a so-called external gear pump, in which a drive gear 2 and a driven gear 3 are arranged in an internal space in a casing 1 so as to rotate the gears 2 and 3. By doing so, it acts as a pump that transfers the fluid trapped in the tooth gap to the suction side as well as the discharge side. Actually, the suction side is positioned upward and the discharge side is positioned downward, and a tank containing high molecular weight polymer or molten resin is installed directly above the intake port 11 to absorb the molten resin in the tank. Discharge at a predetermined discharge pressure.

[0013] The drive gear 2 and the driven gear 3 are each a single point continuous contact tooth-shaped helical gear. In the illustrated example, the tooth profile of both gears 2 and 3 is an arc tooth profile. For each gear 2 and 3, the ratio DZB of outer diameter D to tooth width B is set between 1.1 and 1.15. This is because the gear pump 100 pumps high-temperature molten resin, etc. at a high temperature of about 300 ° C. at a high pressure of about 20 MPaG. According. The specific values of gear outer diameter D and tooth width B are limited by the gear shaft diameter necessary to transmit the rotational driving force to the gear and the shaft diameter necessary to suppress the stagnation deformation of the gear shaft. receive

[0014] Therefore, the ratio of the gear outer diameter D to the tooth width B DZB is within 1.1 to 1.15. The number of teeth Z and the twist angle (helical angle) | 8 decide. If the tooth module is M and the pitch circle diameter is A,

A = MZ,

D = M (Z + 2)

Holds. In this embodiment, since the tooth profile of both gears 2 and 3 is a one-point contact tooth profile, the rotation is not transmitted, such as one pitch screw in the gear shaft direction.

1 pitch = πΑΖΖ = πΜ

And

Β / 2 = πΜ / tanjS

Need to be. If DZB = x, then

Ζ = (2πχ / ίΆΐΐβ) -2

It becomes.

[0015] Note that the twist angle j8 is preferably set to 32 ° or less in terms of the tooth profile processing step. From the above equation, if DZB = x is set within the range of 1.1 to 1.15, the number of teeth will be 10 to 12 when the twist angle j8 is set between 28 ° and 32 °.

[0016] An arc gear pump with an arc tooth profile of M = 20, Z = 10, A = 200, _J 8 = 31 °, B = 209, and a capacity of 4189 cc Zrev was manufactured and compared with a known involute gear pump. The involute gear pump used for performance comparison is M = 14, Z = 14, A = 200, j8 = 2.4 °, B = 209, capacity 4080ccZrev. The shaft diameter and bearing length related to performance were the same for both. At a liquid viscosity of about 300 Pa's and a discharge pressure of 20 MPaG, the circular gear pump obtained the same performance as the involute gear pump. In addition, the confinement phenomenon theoretically does not occur in the arc tooth profile, but when the discharge pressure pulsation was measured as an evaluation of confinement, it was 0.4% for the arc gear pump and 4% for the involute gear pump. All are values under the operating conditions of a liquid viscosity of about 300 Pa's, a discharge pressure of 20 MPaG, and a rotation speed of 30 rpm. Discharge pressure pulsation is measured. The arc pulsating pump reduced the discharge pulsation to lZio compared to the involute gear pump, although it changed depending on the fixed position and other measurement environments.

By the way, as already described, the gear pump 100 of the present embodiment is mainly used for pumping a high-pressure, high-viscosity fluid. Therefore, the inner peripheral shape of the casing 1 is not molded so that the high-viscosity fluid can be sufficiently sucked into the tooth gaps of the gears 2 and 3 and the tip leakage of the high-pressure fluid caught in the tooth gaps can be reduced. must not. Hereinafter, a detailed description will be given with reference to FIG. Here, the positions where the tooth tips of the rotating gears 2 and 3 start to approach the inner peripheral surface of the casing 1 are P, P, and the positions where the tooth tips start to move away from the inner peripheral surface of the casing 1 are P, P, Both gears 2 and 3

1 2 2

The pitch point is P, and the center of each gear 2 and 3 is P and P.

0 c c

[0018] In order to smoothly guide a high-viscosity fluid into the tooth gap, a straight line passing through the centers P and P of both gears 2 and 3 and the center P of the gears 2 and 3 and the sliding contact start point P of the tooth tip As for the angle E formed by the line connecting the two, it is necessary to secure a size of about 0 ° to 6 ° in a side sectional view (a sectional view cut along a plane perpendicular to the gear axis). However, the position of the sliding contact start point P is assumed to be on the discharge side with respect to the straight line passing through the centers P and P of the two gears 2 and 3. In order to reduce tooth tip leakage, the arc angle E (centered from the sliding contact start point P to the sliding contact end point P) is 72 °

1 2 4

It is preferable to ensure the above size. Arc angle E is equal to or greater than two tooth spaces in gears 2 and 3.

Four

It is a guideline to secure. However, if E is increased, the flow path communicating with the discharge port 12 is increased.

Four

E narrows and may interfere with the fluid discharge process.

Four

Should be kept to the size of

[0019] When E is set to 0 ° or more and E is set to 72 ° to 108 °, the sliding contact start point P and the pitch point P are set to

1 4 1 0 The angle E formed by the line segment connecting the line segment connecting the slidable contact end point P and the pitch point P is a side sectional view 33

2 0 2

. ~ 66 °. Therefore, the sliding contact end points P and P and the pitch point P for both gears 2 and 3 are

2 2 0 The angle E between the two line segments that connect each other shall be 48 ° to 102 ° in a side sectional view. Conversely

Three

For example, in order to secure the required E and E (or E), the upper limit of E should be about 102 °

1 2 4 3

There is a need. Needless to say, the lower limit of E is set to about 48 °.

Three

This is to smoothly flow the discharged fluid toward the discharge port 12.

[0020] According to the present embodiment, in the gear pump 100 that transfers fluid from the suction side to the discharge side by rotation of the paired gears 2, 3, the gears 2, 3 are connected to each other in a one-point continuous contact tooth profile. For the gears 2 and 3, the ratio DZB of the gear outer diameter D to the tooth width B is set to 1.1 to 1.15 to avoid adverse effects on the bearing due to fluid confinement. Can do. In addition, by setting DZB to 1.1 to 1.15, efficiency can be ensured while suppressing bearing load, and the pump outer shape is not enlarged. The gear pump 100 of this embodiment is more suitable for transferring a high-pressure, high-viscosity fluid than a conventional involute gear pump.

[0021] Further, since the angle E is 48 ° to 102 ° and the angle E4 is 72 ° to 108 °, the fluid is

3 4

It can be sufficiently sucked into the tooth gaps of cars 2 and 3, and the tooth tip leakage of the fluid caught in the tooth gaps can be reduced.

[0022] The gear pump 100 of the present invention configured as described above is used in the process of manufacturing a polymer or molten resin, or a molded product from a polymer or molten resin. The present invention can be applied to uses for producing a polymer, molten resin or molded product.

For example, as shown in FIG. 3, the monomer is transferred from the monomer tank 110 to the polymerization tank 120 using the gear pump 100 of the present invention to produce a polymer, or the polymer is It can be transferred to the molding apparatus 300 or the spinning apparatus 400 via the pump 100 and used for the process of manufacturing the molded product. Further, even if a process for producing a polymer using the gear pump 100 of the present invention and a process for producing the molded product are integrated, a single production line as shown in FIG. 3 is constructed. Good. The monomer tank 110 and the polymerization tank 120 shown in FIG. 3 can be replaced with a resin pellet tank and a molten resin tank, respectively, to form a production line for a molten resin and a molded product thereof.

Furthermore, the polymerization apparatus 200 can be formed by the monomer tank 110, the gear pump 100, and the polymerization tank 120 shown in FIG. Further, the molding apparatus 300 or the spinning apparatus 400 and the gear pump 100 may be separate from each other, or the molding apparatus 300 or the spinning apparatus 400 incorporating the gear pump 100 may be used.

Note that the present invention is not limited to the embodiment described in detail above. The specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0026] This application is based on Japanese Patent Application No. 2005-048965 filed on February 24, 2005. The contents of the application including the specification, drawings and claims of the application are hereby incorporated by reference in their entirety.

Industrial applicability

The gear pump of the present invention can be suitably used for, for example, a transfer of molten resin and other high molecular weight polymers at a high pressure in oil plants, chemical plants, polymerization plants, molding and spinning devices, and the like. Force Not limited to these, it can be used for transferring high pressure and high viscosity fluids.

Claims

The scope of the claims

[1] A casing having a suction port into which a fluid is introduced and a discharge port from which the fluid is discharged, and provided in the casing, and meshed with each other to rotate to draw the fluid to the suction port force to the discharge port And a pair of gears to transfer,

The pair of gears are one-point continuous contact tooth-shaped helical gears,

A gear pump having a specific force between an outer diameter and a tooth width of each of the gears is 1.1 to 1.15.

[2] The gear pump according to claim 1, wherein the number of teeth of each of the gears is 10 to 12, and the twist angle of each of the gears is 28 ° to 32 °.

[3] In the inner peripheral shape of the casing,

An angle formed by a line segment connecting a position where each tooth tip of the rotating gear is separated from the inner peripheral surface of the casing and a pitch point of the gear is 48 ° to 102 ° in a side sectional view. Item 1. The gear pump according to Item 1.

[4] In the inner peripheral shape of the casing,

An angle formed by a line segment connecting a position where each tooth tip of the rotating gear is separated from the inner peripheral surface of the casing and a pitch point of the gear is 48 ° to 102 ° in a side sectional view. Item 2. The gear pump according to Item 2.

[5] In the inner peripheral shape of the casing,

The arc angle from the position at which the tooth tip of the rotating gear is in close proximity to the inner peripheral surface of the casing to the position at which the tooth tip of the gear is separated from the inner peripheral surface of the casing is 72 ° in side sectional view. The gear pump according to claim 1, wherein the gear pump is ~ 108 °.

[6] In the inner peripheral shape of the casing,

The arc angle from the position at which the tooth tip of the rotating gear is in close proximity to the inner peripheral surface of the casing to the position at which the tooth tip of the gear is separated from the inner peripheral surface of the casing is 72 ° in side sectional view. The gear pump according to claim 2, wherein the gear pump is -108 °.

[7] In the inner peripheral shape of the casing,

The arc angle from the position at which the tooth tip of the rotating gear is in close proximity to the inner peripheral surface of the casing to the position at which the tooth tip of the gear is separated from the inner peripheral surface of the casing is the cross-sectional view. The gear pump according to claim 3, wherein the gear pump is 72 ° to 108 °.

[8] In the inner peripheral shape of the casing,

The arc angle from the position at which the tooth tip of the rotating gear is in close proximity to the inner peripheral surface of the casing to the position at which the tooth tip of the gear is separated from the inner peripheral surface of the casing is the cross-sectional view.

The gear pump according to claim 4, wherein the gear pump is 72 ° to 108 °.

[9] A high molecular weight polymer using the gear pump according to claim 1, in the production of a high molecular weight polymer or a molten resin, or in the process of manufacturing a molded product from the high molecular weight polymer or the molten resin, A method for producing a molten resin or molded product.

[10] A high molecular weight polymer using the gear pump according to claim 2, in the process of producing a high molecular weight polymer or a molten resin, or producing a molded product from the high molecular weight polymer or the molten resin. A method for producing a molten resin or molded product.

[11] A polymerization apparatus using the gear pump according to claim 1.

[12] A polymerization apparatus using the gear pump according to claim 2.

[13] A molding apparatus using the gear pump according to claim 1.

14. A molding apparatus using the gear pump according to claim 2.

15. A spinning apparatus using the gear pump according to claim 1.

16. A spinning device using the gear pump according to claim 2.