CN110671335B - A counter-rotating structure multistage high temperature pump - Google Patents

Abstract

The invention provides a multi-stage high-temperature pump with a counter-rotation structure, comprising a casing, a secondary impeller and a first-stage impeller; the casing is sequentially provided with a suction chamber, a first-stage guide vane and a secondary guide vane according to the flow direction of the suction fluid and pump body; a rotatable first-stage impeller is coaxially installed between the suction chamber and the first-stage guide vane, and a rotatable secondary impeller is coaxially installed between the first-stage guide vane and the secondary guide vane, and the The rotational speed of the primary impeller and the secondary impeller are different, and the rotation of the primary impeller and the secondary impeller are different. A hollow shaft is supported in the first stage guide vane and the secondary guide vane, and the hollow shaft is drivingly connected with the secondary impeller; the solid shaft is supported in the hollow shaft, and the solid shaft passes through the hollow shaft Connected with the first stage impeller. The invention solves the problems of narrow high-efficiency area, low efficiency during small flow operation, unit vibration and poor anti-cavitation performance, greatly reduces the influence of pre-swirl at the outlet of the first-stage guide vane, and effectively increases the pump head.

Description

A counter-rotating structure multistage high temperature pump

technical field

The invention relates to the field of high temperature pumps, in particular to a multi-stage high temperature pump with a counter-rotation structure.

Background technique

At present, with the continuous adjustment of the energy structure, the proportion of pump products in the actual production is getting higher and higher. The multi-stage pump is mainly based on centrifugal impeller, and adopts multi-stage series structure to meet the demand of high lift. Therefore, it is widely used in important fields of national defense and national economy such as nuclear energy, chemical industry, electric power and so on. Generally, traditional centrifugal pumps have difficulties in design, such as large volume, narrow high-efficiency area, and low efficiency during small flow operation, and problems such as vibration, noise, and cavitation occur, which seriously affect the safety and reliability of system operation. In a multi-stage pump, the secondary head is reduced due to the pre-swirl at the outlet of the first-stage guide vane. The counter-rotation structure can reduce the influence of the pre-swirl at the outlet of the upper-stage guide vane, thereby effectively increasing the pump head. The Chinese invention patent discloses a dual-drive counter-rotating axial flow pump, which broadens the scope of the axial flow pump and can partially replace the mixed flow pump. However, this structure uses a dual-drive design at both ends, which is not convenient for installation and use, and at the same time, the inlet is likely to cause a large hydraulic loss.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the present invention provides a multi-stage high-temperature pump with a counter-rotating structure, which solves the problems of narrow high-efficiency area, low efficiency during small flow operation, unit vibration, and poor anti-cavitation performance, etc. The influence of the pre-swirl at the outlet of the stage guide vane can effectively improve the pump head.

The present invention achieves the above technical purpose through the following technical means.

A multi-stage high-temperature pump with a counter-rotating structure, comprising a casing, which is provided with a suction chamber, a first-stage guide vane, a secondary guide vane and a pump body in sequence according to the flow direction of the suction fluid, and also includes a secondary impeller and a first-stage Impeller; a rotatable first-stage impeller is coaxially installed between the suction chamber and the first-stage guide vane, and a rotatable secondary impeller is coaxially installed between the first-stage guide vane and the secondary guide vane, and the first-stage The rotational speeds of the impeller and the secondary impeller are different, and the rotations of the primary impeller and the secondary impeller are different.

Further, it also includes a solid shaft and a hollow shaft, the first stage guide vane and the secondary guide vane support a hollow shaft, and the hollow shaft is drivingly connected with the secondary impeller; the solid shaft is supported in the hollow shaft, and The solid shaft passes through the hollow shaft and is drivingly connected with the first-stage impeller.

Further, one end of the hollow shaft is connected to the first transmission device through the casing; a first bushing is mounted on the first-stage guide vane, a second bushing is mounted on the secondary guide vane, and the other end of the hollow shaft is mounted It is supported by the first bushing and the second bushing.

Further, one end of the solid shaft passes through the first transmission device and is connected to the second transmission device; the other end of the solid shaft passing through the hollow shaft is provided with a shaft shoulder, and a shaft shoulder is provided between the shaft shoulder and the end face of the other end of the hollow shaft. There are plane bearings.

Further, a bushing chamber is fixed in the suction chamber through a guide rib, a third bushing is installed in the bushing chamber, and the other end of the solid shaft passes through the first-stage impeller and is supported in the third bushing.

Further, the surface of the solid shaft is plated with copper to prevent the shaft from expanding and deforming due to heat.

Further, the rotational speed of the first-stage impeller is smaller than the rotational speed of the secondary impeller.

Further, the ratio of the rotational speed of the first-stage impeller to the rotational speed of the secondary impeller ranges from 0.5 to 0.7.

Further, a constant pressure air supply device is also included, and the gap between the solid shaft and the hollow shaft is an air chamber; the constant pressure air supply device is used to deliver constant pressure inert gas into the air chamber.

The beneficial effects of the present invention are:

Compared with the single-stage pump, the multi-stage high-temperature pump of the counter-rotation structure of the present invention can not only reduce the pre-rotation of the first-stage guide vane outlet, improve the operation stability of the pump, but also improve the pump head; The pump of the invention is not only small in size and relatively simple in structure, but also can improve the anti-cavitation performance; the invention can also prevent the crystallization of the conveying medium from blocking the air chamber under cold working conditions, and avoid the crystallization of the conveying medium from sticking to the shaft and causing the wear of dynamic and static parts.

Description of drawings

FIG. 1 is a cross-sectional view of the casing of the multi-stage high temperature pump of the counter-rotation structure according to the present invention.

FIG. 2 is a schematic structural diagram of the multi-stage high temperature pump of the counter-rotation structure according to the present invention.

FIG. 3 is a partial enlarged view of FIG. 1 .

In the picture:

1-suction chamber; 2-sleeve chamber; 3-thrust washer; 4-guide rib; 5-first-stage impeller; 6-first-stage guide vane; 7-first bushing; 8-secondary impeller; 9-Secondary guide vane; 10-Second bushing; 11-Solid shaft motor; 12-Hollow shaft motor; 13-Pump body; 14-Third bushing; 15-Solid shaft; 16-Hollow shaft; 17- Snap ring; 18-constant pressure air supply device; 19-copper plating; 20-air chamber; 21-plane bearing.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

As shown in FIG. 1 and FIG. 2 , the counter-rotating structure multi-stage high-temperature pump according to the present invention includes a casing, a secondary impeller 8 and a first-stage impeller 5, and the casing is provided with a suction chamber in sequence according to the flow direction of the suction fluid 1. The first-stage guide vane 6, the secondary guide vane 9 and the pump body 13; the suction chamber 1, the first-stage guide vane 6, and the secondary guide vane 9 are arranged coaxially. A rotatable first-stage impeller 5 is coaxially installed between the suction chamber 1 and the first-stage guide vane 6, and a rotatable secondary impeller 8 is coaxially installed between the first-stage guide vane 6 and the secondary guide vane 9, The first-stage impeller 5 is fixed on the solid shaft 15 by the snap ring 17 , and the secondary impeller 8 is fixed on the hollow shaft 16 by the snap ring 17 . The rotational speeds of the first-stage impeller 5 and the secondary impeller 8 are different, and the rotations of the first-stage impeller 5 and the secondary impeller 8 are different.

The first-stage guide vane 6 and the secondary guide vane 9 support a hollow shaft 16, and the hollow shaft 16 is drivingly connected with the secondary impeller 8; the solid shaft 15 is supported in the hollow shaft 16, and the solid shaft 15 is The shaft 15 is connected to the first-stage impeller 5 through the hollow shaft 16 in a driving manner. One end of the hollow shaft 16 is connected to the hollow shaft motor 12 or the reduction box through the casing; the first shaft sleeve 7 is installed on the first-stage guide vane 6, and the second shaft sleeve 10 is installed on the secondary guide vane 9, The other end of the hollow shaft 16 is supported by the first bushing 7 and the second bushing 10 . One end of the solid shaft 15 is connected to the solid shaft motor 11 through the output shaft of the hollow shaft motor 12; one end of the solid shaft 15 can also be connected to another reduction box through the reduction box; The other end of the shaft 15 is provided with a shaft shoulder, and a plane bearing 21 is provided between the shaft shoulder and the end face of the other end of the hollow shaft 16 .

In the suction chamber 1, the bushing chamber 2 is fixed by the guide rib 4, the third bushing 14 is installed in the bushing chamber 2 and is positioned by the thrust washer 3, and the other end of the solid shaft 15 passes through the first stage The impeller 5 is supported in the third shaft sleeve 14 afterward.

As shown in FIG. 3 , the gap between the solid shaft 15 and the hollow shaft 16 is the air chamber 20 ; the constant pressure air supply device 18 is used to deliver constant pressure inert gas into the air chamber 20 , in order to prevent the high temperature medium from Under cold working conditions, the crystallization blocks the air chamber to avoid the crystallization of the conveying medium from sticking to the shaft and causing the wear of the dynamic and static parts.

The rotational speed of the first-stage impeller 5 is lower than the rotational speed of the secondary impeller 8 . The ratio of the rotational speed of the first-stage impeller 5 to the rotational speed of the secondary impeller 8 ranges from 0.5 to 0.7, which is convenient to increase the pressure at the inlet of the secondary impeller 8; the rotation directions of the first-stage impeller 5 and the secondary impeller 8 are different. Viewed from the pump inlet direction, the primary impeller 5 rotates clockwise, and the secondary impeller 8 rotates counterclockwise; the hollow shaft 16 and the solid shaft 15 are made of stainless steel, and the outer surface of the solid shaft 15 adopts copper plating technology , is provided with a copper-plated layer 19 to prevent the shaft from expanding and deforming due to heat; the solid shaft 15 and the hollow shaft 16 should be installed to ensure concentricity.

In the actual operation process of the multi-stage high temperature pump of the counter-rotation structure of the present invention, the secondary impeller 8 and the primary impeller are driven respectively by the hollow shaft 16 and the solid shaft 15 provided on the hollow shaft motor 12 and the solid shaft motor 11 . 5. The rotation directions of the primary impeller 5 and the secondary impeller 8 are different. If viewed from the pump inlet direction, the primary impeller 5 rotates clockwise, and the secondary impeller 8 rotates counterclockwise. At the same time, by adjusting the frequency conversion of the hollow shaft motor 12 and the solid shaft motor 11, the rotation direction and rotation speed of the first-stage impeller 5 and the secondary impeller 8 in the counter-rotating mechanism are controlled to improve the working condition adaptability of the unit.

With the operation of the unit, the first-stage impeller 5 will rotate with the solid shaft 15 , driving the working medium to enter the first-stage guide vane 6 , and then enter the secondary impeller 8 through the guide of the first-stage guide vane 6 . The residual energy flowing out of the first-stage impeller 5 is fully utilized by the secondary impeller 8, and at the same time, there is no pre-swirl, which increases the lift. The secondary impeller 8 will rotate in the opposite direction of the hollow shaft 16 and the solid shaft 15 , driving the working medium to enter the secondary guide vane 9 , and finally flow out of the pump body 13 through the secondary guide vane 9 .

The embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or Modifications all belong to the protection scope of the present invention.

Claims (8)

1. A counter-rotating structure multi-stage high-temperature pump comprises a shell, wherein the shell is sequentially provided with a suction chamber (1), a first stage guide vane (6), a second stage guide vane (9) and a pump body (13) according to the flow direction of sucked fluid, and is characterized by further comprising a second stage impeller (8), a first stage impeller (5), a solid shaft (15) and a hollow shaft (16); a rotatable primary impeller (5) is coaxially arranged between the suction chamber (1) and the primary guide vane (6), a rotatable secondary impeller (8) is coaxially arranged between the primary guide vane (6) and the secondary guide vane (9), the rotating speeds of the primary impeller (5) and the secondary impeller (8) are different, and the rotating directions of the primary impeller (5) and the secondary impeller (8) are different; a hollow shaft (16) is supported in the first stage guide vane (6) and the second stage guide vane (9), and the hollow shaft (16) is in transmission connection with a secondary impeller (8); the solid shaft (15) is supported in the hollow shaft (16), and the solid shaft (15) penetrates through the hollow shaft (16) to be in transmission connection with the primary impeller (5).

2. A counter-rotating multistage high temperature pump according to claim 1, wherein one end of the hollow shaft (16) is connected to a first transmission through the housing; install first axle sleeve (7) on first grade stator (6), install second axle sleeve (10) on secondary stator (9), the hollow shaft (16) other end is supported through first axle sleeve (7) and second axle sleeve (10).

3. A counter-rotating multistage high-temperature pump according to claim 1, wherein one end of the solid shaft (15) is connected with a second transmission device through a first transmission device; the other end of the solid shaft (15) penetrating through the hollow shaft (16) is provided with a shaft shoulder, and a plane bearing (21) is arranged between the shaft shoulder and the end face of the other end of the hollow shaft (16).

4. A pair-rotation structure multi-stage high-temperature pump according to claim 3, wherein the shaft sleeve chamber (2) is fixed in the suction chamber (1) through the guide rib plates (4), a third shaft sleeve (14) is installed in the shaft sleeve chamber (2), and the other end of the solid shaft (15) passes through the first-stage impeller (5) and is supported in the third shaft sleeve (14).

5. A counter-rotating multi-stage high-temperature pump according to claim 1, wherein the solid shaft (15) is plated with copper on the surface for preventing the shaft from thermal expansion deformation.

6. A counter-rotating multistage high temperature pump according to any one of claims 1 to 5, wherein the rotation speed of the primary impeller (5) is less than the rotation speed of the secondary impeller (8).

7. A counter-rotating multi-stage high-temperature pump according to claim 6, wherein the ratio of the rotation speed of the primary impeller (5) to the rotation speed of the secondary impeller (8) is in the range of 0.5-0.7.

8. A counter-rotating multistage high-temperature pump according to claim 1, further comprising a constant-pressure gas supply device (18), wherein the gap between the solid shaft (15) and the hollow shaft (16) is a gas chamber (20); the constant-pressure gas supply device (18) is used for conveying constant-pressure inert gas into the gas chamber (20).

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