JP2008522093A - Pump for positive pressure liquid - Google Patents

Abstract

The pump for positive pressure liquid has a pump chamber 18 that houses the impeller 24, and the impeller 24 is eccentric in the axial direction with respect to the non-rotating support member 48 that defines the axial position of the impeller 24. The shaft 42 can be connected to the drive shaft 64 via magnet couplings 56 and 62.

Description

The present invention relates to a positive pressure liquid pump having a pump chamber that houses an impeller.

When the liquid is sucked at a temperature higher than the boiling point, it is necessary to maintain a high pressure in order to prevent the liquid from evaporating. Therefore, for example, a pump used for hot water at 120 ° C. must be operated at 0.25 MPa (2.5 bar), assuming that there is no pressure loss. When the temperature rises by 10 ° C., it is necessary to increase the pressure by about 0.1 MPa.

In the case of an impeller type pump, in order to maintain such a high pressure during pump operation, it is necessary to provide a small tolerance in the gap between the impeller and the wall surface of the pump chamber adjacent to the impeller. When this play increases by 1/10 mm, for example, the pressure decreases by 0.1 MPa. On the other hand, in order to suppress wear of the impeller provided on the shaft supported in a floating state, a certain small gap is required.

It is an object of the present invention to provide a pump of the type described above that is less friable when sucking liquid and at the same time maintains a high pressure.

According to the present invention, the above object is achieved by a pump in which the impeller is eccentric in the axial direction with respect to the non-rotating support member that defines the axial position of the impeller. Since the axial position of the impeller is determined by the support member, the dimensions of the pump chamber and the impeller are adapted to each other with very high accuracy, so that the gap between the impeller and the wall of the pump chamber is very high. Keep small. Therefore, for example, it is optimal as a pump for sucking hot water at a high temperature and a high pressure corresponding thereto.

Further modifications and useful examples of the invention are indicated in the dependent claims.

The impeller is preferably provided fixed to a shaft eccentric in the axial direction with respect to the support member. As a result, a sliding rotation operation between the shaft and the support member occurs on the small radius, and as a result, the frictional resistance is reduced. In order to further reduce friction, the shaft and the support member are preferably made of a ceramic material.

The shaft is preferably supported by at least one radial slide bearing. Thereby, the position of the impeller in the radial direction is determined with high accuracy. In order to reduce the dynamic friction force, the shaft and the slide bearing are preferably made of a ceramic material. Since the shaft is movably supported by the bearing, the shaft and the impeller can be eccentric in the axial direction with respect to the support member.

The support member and the at least one slide bearing are preferably cleaned by aspirated liquid while the pump is in operation.

A washing passage through the wall of the pump chamber for washing away at least one slide bearing preferably communicates the pressure side portion of the pump chamber with the portion located above the slide bearing. In this way, the slide bearing is reliably cleaned by the sucked liquid.

As a preferred embodiment, the washing passage for washing away at least one slide bearing is constituted by a passage that passes through the shaft in the axial direction. This passage may be added to a cleaning passage formed in the wall surface of the pump chamber.

The cleaning passage of the present invention can be operated not only when the impeller rotates in the horizontal axis direction, but also when the impeller rotates, that is, when the impeller rotates in the vertical axis direction.

The play in the radial direction between the impeller and the pump chamber is preferably 1/10 mm or less. This corresponds to an average distance of 5/100 mm between the impeller and the wall surface of the pump chamber. This play is particularly preferably 5/100 mm or less corresponding to an average interval of 0.025 mm.

As for any surface of the impeller, the axial interval between the impeller and the pump chamber is preferably 1/10 mm or less. This interval is preferably 5/100 mm or less, particularly preferably 3/100 mm or less.

The temperature and pressure allowed for the pump according to the invention can be further increased by omitting the seal in the rotating part. According to a further modification of the invention, the shaft is connected to the drive shaft via a magnet coupling, the first connection member of the magnet coupling is connected to the shaft, and the second connection of the magnet coupling. The member is connected to the drive shaft, and the wall that seals the drive side portion of the pump relative to the pump housing and the portion that houses the shaft passes through the gap between the first and second connection members.

By utilizing the magnet coupling, the contact between the first and second connecting members does not occur in the gap of the magnet coupling, so that the sealing of the rotating portion can be omitted. As a result, the pump can operate in a pressure range of 0.6 to 0.65 MPa, for example, and as a result, for example, hot water at 160 ° C. can be sucked. At such temperatures, for example, conventional rubber seals cannot be used.

It is preferable that the first connection member and the second connection member are provided at relative positions such that the magnet coupling propels the shaft in the axial direction with respect to the support member. Thereby, the magnet coupling has two actions. For one thing, the blocking wall can seal the portion of the pump containing the aspirated liquid, so that there is no need to provide a seal on the rotating portion. The other is that the impeller and the shaft are reliably eccentric in the axial direction with respect to the support member.

In another embodiment of the invention, the shaft is eccentric in the axial direction with respect to the support member by a compression spring. The compression spring may be used when a magnet coupling is provided.

A preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a partial sectional view showing a first embodiment of a pump having a magnetic coupling, and FIG. 2 is a partial sectional view showing a second embodiment of a pump having a slip ring seal and a compression spring.

The pump shown in FIG. 1 has a substantially cylindrical casing 10, a mediating member 12 is attached to the lower end thereof, and a head member 14 is attached to the mediating member. These members are securely screwed to the casing 10 by means of bolts 16 that penetrate the head member 14. A pump chamber 18 is formed in the intermediate member 12 and the head member 14. The pump chamber 18 extends in the form of a blocking ring between the intermediate member 12 and the head member 14, and a suction pipe (not shown). The suction passage and the discharge passage 20 of the discharge pipe 22 are communicated with each other. In the cross-sectional view shown in FIG. 1, the discharge pipe 22 formed on the intermediate member 12 is located behind the drawing, while a suction passage (not shown) is formed on the head member 14 and located on the front surface of the drawing.

The pump chamber 18 accommodates an impeller 24 having a disk-shaped central portion 26 and impeller blades 28 and 30 provided above and below the central portion 26. The central portion 26 and the impeller blades 28 and 30 extend in the radial direction at the outer peripheral portion of the impeller 24. The blade 28 provided on the upper portion of the central portion 26, that is, on the discharge passage 20 side, is formed to move slightly toward the rear side in the rotational direction of the impeller 24 compared to the blade 30 provided on the lower portion of the central portion 26. Yes. The blade 28 extends upward in the axial direction toward the upper surface 32 of the impeller 24. The blade 30 extends downward in the axial direction toward the lower surface 34 of the impeller 24. On the radially inner side of the pump chamber 18, the upper surface 32 is close to the wall surface formed on the mediating member 12, for example, a gap of 2/100 mm is formed, whereas the lower surface 34 is formed on the head member 14. Close to the wall surface, for example, a 3/100 mm gap is formed.

The blades 28, 30 and the central portion 26 of the impeller 24 extend radially outward toward the linear outer periphery 36 of the impeller 24. Between the terminal end of the pump chamber 18 of the discharge passage 20 and the start end of the pump chamber 18 of the suction passage 20, the outer peripheral edge 36 has a lateral gap of, for example, only 0.025 mm from the wall surface formed by the head member 14. Have. The small lateral and axial clearance between the impeller 24 and the surrounding wall allows the pump to maintain very high pressure.

The impeller 24 is fixed to a shaft 42 made of ceramic material by means of a sleeve-shaped protrusion 38 and means of a tolerance or corrugated ring 40. Under the impeller 24, the shaft 42 is supported by a slide bearing 44 fixed to the head member 14 by a wave ring 46. The slide bearing 44 is made of a ceramic material such as silicon carbonate.

The shaft 42 is slidably supported at a lower end portion thereof on a ceramic support member 48 formed of, for example, a tungsten carbonate penetrating disk.

The shaft 42 is guided at the top of the impeller 24 to another slide bearing 52 that is fixed to the mediating member 12 by a corrugated ring 54.

The first coupling member 56 of the magnet coupling is fixed to the upper end portion of the shaft 42 by a corrugated ring 58. The first coupling member 56 extends annularly around the end of the shaft 42 and is surrounded by an annular flange 60 of the second coupling member 62 of the magnet coupling with a gap. The second coupling member 62 is fixed to the lower end portion of the drive shaft 64 supported by the casing 10 by a fixed bearing 66. The drive shaft 64 is driven by a pump motor.

The partition can 68 is provided in a bowl-shaped hollow space formed between the coupling members 56, 62, and in the region of the annular gap 70 formed between the first coupling member 56 and the flange 60, It has a very thin wall.

The partition can 68 constitutes a wall surface made of a nonmagnetic material such as VA steel. The septum can 68 is sealed to the intermediate member 12 by the seal ring 72, and the intermediate member 12 is sealed to the head member 14 by the seal ring 74. In this way, a closed hollow space is formed that surrounds the pump chamber 18 and is open only at the portions of the suction passage and the discharge passage 20.

The magnet member 76 provided on the first coupling member 56 is provided opposite to the magnet member 78 provided on the flange 60 in the annular gap 70 portion. These magnetically transmit drive torque from the drive shaft 64 to the shaft 42 and thus to the impeller 24. The magnet members 76 and 78 are relatively offset in the axial direction so that they exert an axial force on the shaft 42. This force acts on the shaft 42 with respect to the support member 48 and is eccentric. In this way, the axial position of the impeller 24 relative to the head member 14 and the mediating member 12 is accurately determined, and as a result, the impeller 24 and these members, despite the very small axial clearance. There is no contact between the two. For this reason, the pump will operate with very little wear.

The cleaning passage 80 starts near the discharge side end of the pump chamber 18 and passes upward through the intermediate member 12 and opens in the region of the coupling member 56. The cleaning passage 80 is constituted by a linear hole tapered at the lower end portion thereof to restrict inflow into the cleaning passage.

The purpose of flowing the liquid upward through the cleaning passage 80 is to clean the slide bearing 52. Further, the liquid is guided to the lower end portion of the shaft 42 through a passage 82 which is an axial through hole of the shaft 42, where the liquid is provided in order to clean the slide bearing 44. It passes through the groove 84 and is discharged in the lateral direction.

The embodiment of the present invention shown in FIG. 2 differs from the embodiment shown in FIG. 1 in that no magnet coupling is provided. Similar components are denoted by similar reference numerals.

The impeller 24 is fixed to the shaft 86 by the corrugated ring 40, and the shaft 86 is supported by the slide bearing 44 at the lower end portion thereof, and is supported by the support member 48 in the same manner as the vehicle driver 42 shown in FIG. 1. However, the shaft 86 is reduced in diameter at the upper end thereof, passes through the hole 88 of the intermediate member 12, and is connected to the drive shaft 64 by the tappet sleeve 90. The gap between the shaft 86 and the hole 88 is sealed by a slip ring seal 92 at the seal surface 94. Through the sleeve member 96, the slip ring seal 92 is pressed upward against the seal surface 94 by a compression spring 98 whose lower end is supported by the shoulder of the shaft 86.

Since the shaft 86 is slidably guided within the tappet sleeve 90, the slip ring seal 92, the sleeve member 96, the slide bearing 44 and the compression spring 98 simultaneously push the shaft downward relative to the support member 48. In this way, as in the first embodiment, the exact axial position of the impeller 24 relative to the head member 14 and the intermediate member 12 is determined.

In addition, the small gap between the impeller 24 and the adjacent wall surface of the pump chamber 18 is formed by the exact axial and radial positions of the impeller 24 as described above. This allows the pump to operate with very little wear and without using a slip ring seal on the rotating shaft 86 and to operate with very high temperature and pressure of suction liquid. Therefore, for example, warm water in the range of 120 to 130 ° C. can be sucked.

In order to clean the slide bearing 44, a transverse hole 100 is provided in the shaft 86 above the sleeve-like projection 38 and the impeller 24, which transverse hole opens into the passage 102 formed by the axial hole of the shaft 86; The cleaning liquid for the slide bearing is supplied from the upper part of the intermediate member 12 toward the lower end of the shaft 86 and is discharged through the groove 84 here.

The discharge and cleaning passage 104 extends from the upper end of the head member 12 toward the discharge passage 20 at a substantially lower height position of the slip ring seal 92, and passes through the web 106 formed in the discharge pipe 22.

In the embodiment of the pump described above, the structures of the head member 14 and the casing 10 are not particularly limited, and the same applies to the drive shaft 64. In each embodiment, the intermediate member 12, the head member 14, the impeller 24, and the shafts 42 and 86 can be replaced according to maintenance purposes. Furthermore, the lower end of the pump according to one embodiment may be replaced with the other. The drive line where the replacement part is mounted on the top of the pump is always located outside the suction liquid.

It is a fragmentary sectional view showing a 1st embodiment of a pump which has a magnet coupling. It is a fragmentary sectional view showing a 2nd embodiment of a pump which has a slip ring seal and a compression spring.

Claims (10)

A positive pressure liquid pump having at least one pump chamber (18) for accommodating the impeller (24), wherein the impeller (24) is a non-rotating support member that defines an axial position of the impeller (24). 48) A pump characterized in that it is eccentric in the axial direction with respect to 48). The pump according to claim 1, wherein the impeller (24) is fixed to a shaft (42, 86) eccentric in the axial direction with respect to the support member (48). The pump according to claim 1 or 2, characterized in that the shaft (42, 86) is supported by at least one radial slide bearing (44, 52). A wash passage (80) through the wall of the pump chamber (18) for flushing the at least one slide bearing (44, 52) is connected to the pressure bearing portion of the pump chamber (18) by the slide bearing (52). 4. The pump according to claim 3, wherein the pump is in communication with a portion located above. The cleaning passage for washing out the at least one slide bearing (44) comprises a passage (82, 100) passing through the shaft (42, 86) in an axial direction. 4. The pump according to 4. The pump according to any one of claims 1 to 5, wherein a play in a radial direction between the impeller (24) and a wall surface of the pump chamber (18) is 1/10 mm or less. The radial play between the impeller (24) and each wall surface of the pump chamber (18) is 1/10 mm or less for any surface of the impeller (24). The pump in any one of 1-6. The shaft (42) is connected to the drive shaft (64) via a magnet coupling (56, 62), and the first connecting member (56) of the magnet coupling is connected to the shaft (42). The second coupling member (62) of the magnet coupling is connected to the drive shaft (64), and the pump drive side with respect to the portion accommodating the shaft (42) and the pump chamber (18). The pump according to any one of claims 1 to 7, wherein a wall surface (68) for sealing the portion passes through a gap (70) between the first and second connecting members. In the first connection member (56) and the second connection member (82), the magnet coupling (56, 62) is eccentric in the axial direction of the shaft (42) with respect to the support member (48). 9. The pump according to claim 8, wherein the pump is provided at a relative position. The pump according to any one of claims 1 to 9, wherein the shaft (42) is eccentric in the axial direction with respect to the support member (48) by a compression spring (98).

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