阅读说明：本技术 一种节段式离心泵背叶片 (Sectional centrifugal pump back vane ) 是由 潘强 张德胜 施卫东 赵睿杰 于 2021-10-08 设计创作，主要内容包括：本发明提供了一种节段式离心泵背叶片,包括叶轮后盖板、背叶片节段；叶轮后盖板中心具有圆柱状台阶,所述圆柱状台阶中心为通孔,所述叶轮后盖板具有多条起始于圆柱状台阶、并沿径向延伸的定位筋,所述定位筋上分布多个定位孔；每一条定位筋上均安装多个背叶片节段,且由螺栓固定在定位筋上的定位孔上。通过使用不同数量的节段,组成长度可调节的背叶片,提供不同程度的封压能力,从而实现防止液体泄漏和空气进入的双向密封。(The invention provides a sectional centrifugal pump back blade, which comprises an impeller back cover plate and a back blade section; the center of the impeller rear cover plate is provided with a cylindrical step, the center of the cylindrical step is provided with a through hole, the impeller rear cover plate is provided with a plurality of positioning ribs which start from the cylindrical step and extend along the radial direction, and a plurality of positioning holes are distributed on the positioning ribs; each positioning rib is provided with a plurality of back blade segments and is fixed on the positioning holes on the positioning ribs by bolts. By using different numbers of segments to form the back vane with adjustable length, different degrees of pressure sealing capability are provided, thereby realizing bidirectional sealing for preventing liquid leakage and air from entering.)

1. A segmental centrifugal pump back vane is characterized by comprising an impeller back cover plate (1) and back vane segments; the impeller rear cover plate (1) is provided with a cylindrical step at the center, a through hole (2) is formed in the center of the cylindrical step, the impeller rear cover plate (1) is provided with a plurality of positioning ribs (3) which start from the cylindrical step and extend along the radial direction, and a plurality of positioning holes (4) are distributed in the positioning ribs (3); all install a plurality of back of the body blade sections on each location muscle (3), and fix on the locating hole on location muscle (3) by bolt (8).

2. The sectional centrifugal pump back vane according to claim 1, wherein the plurality of positioning ribs (3) are evenly distributed circumferentially on the impeller backplate (1) and extend all the way to the impeller backplate rim (9).

3. The segmented centrifugal pump back blade according to claim 1, wherein the back blade segment is divided into an a-type back blade segment (5) and a B-type back blade segment (6), one end surface of the a-type back blade segment (5) is a concave arc curved surface for connecting the side surface of the cylindrical step (6), and the other end surface is a flat surface for connecting the B-type back blade segment (7); the two end faces of the B-type back blade segment (7) are both planes and are used for connecting the A-type back blade segment (5) with the B-type back blade segment (7) or connecting the two B-type back blade segments (7).

4. The back blade of the sectional centrifugal pump according to claim 3, wherein each positioning rib (3) is provided with an A-type back blade segment (5) and a plurality of B-type back blade segments (6), the A-type back blade segment (5) is positioned close to the cylindrical step, and one surface of the A-type back blade segment (5) close to the cylindrical step is a concave arc curved surface.

5. The segmented centrifugal pump back blade of claim 1, wherein the type a back blade segment (5) and the type B back blade segment (6) are of uniform length, 0.02D-0.05D where D is the diameter at the impeller back shroud rim (9).

6. The back blade of the sectional centrifugal pump according to claim 1, wherein the lower end surfaces of the A-type back blade section (5) and the B-type back blade section (7) are provided with channels, the width and the height of the channels are matched with those of the positioning ribs (3), the upper end surfaces of the A-type back blade section and the B-type back blade section are provided with through holes, the bolts (8) are connected with the positioning holes (4) after passing through the through holes, and the relative positions of the sections and the impeller back cover plate (1) are fixed.

7. The segmented centrifugal pump back vane according to claim 1, wherein the distance between the locating holes (4) is consistent with the back vane segment length.

8. The segmented centrifugal pump back blade of claim 1, wherein the radius of the side of the cylindrical step (6) is identical to the radius of the curved surface of the a-type back blade segment (5), and the height of the cylindrical step (6), the height of the a-type back blade segment (5), and the height of the B-type back blade segment (7) are identical.

9. The segmented centrifugal pump back vane according to claim 1, wherein the number of positioning ribs (3) is 5-7.

Technical Field

The invention relates to the technical field of fluid machinery, in particular to a back blade of a sectional centrifugal pump.

Background

The pump is a prime mover for increasing potential energy, pressure energy and kinetic energy of liquid, and is divided into a centrifugal pump, a mixed flow pump and an axial flow pump according to the specific rotating speed. The centrifugal pump has low specific speed and high lift, and a sealing device called a shaft seal is needed to be arranged in order to balance the pressure difference between fluid in the pump and atmosphere outside the pump and prevent the fluid from leaking outwards. The back blade seal is one kind of shaft seal, and the back blade is installed onto the back cover plate of the impeller to produce pressure during rotation and prevent liquid from leaking from the rotating shaft gap.

However, the conventional back blade is fixed to the back cover plate of the impeller, the length of the conventional back blade cannot be adjusted, the back blade rotates synchronously when the impeller rotates, and the pressure generated by the back blade is constant. The sealing effect of a conventional back-vane will be quite limited when the pressure at the inlet of the centrifugal pump varies, for example: when the pressure at the inlet of the centrifugal pump is increased, the pressure generated by the back blade is lower than the sealing pressure value, and liquid leaks outwards from the gap of the rotating shaft; when the inlet pressure of the centrifugal pump is reduced, the pressure generated by the back vane is higher than the sealing pressure value, and air enters the pump cavity from the gap of the rotating shaft inwards. Both liquid leakage and air intake can lead to unstable operation of the centrifugal pump, and in severe cases, accidents can occur.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a sectional centrifugal pump back blade which is composed of a plurality of sections, each section can be connected with or detached from the back blade, and the back blade with adjustable length is composed by using different numbers of sections to provide different degrees of pressure sealing capacity, thereby realizing the bidirectional sealing for preventing liquid leakage and air from entering.

A segmental centrifugal pump back vane is characterized by comprising an impeller back cover plate and a back vane segment; the center of the impeller rear cover plate is provided with a cylindrical step, the center of the cylindrical step is provided with a through hole, the impeller rear cover plate is provided with a plurality of positioning ribs which start from the cylindrical step and extend along the radial direction, and a plurality of positioning holes are distributed on the positioning ribs; each positioning rib is provided with a plurality of back blade segments and is fixed on the positioning holes on the positioning ribs by bolts.

Further, the plurality of positioning ribs are uniformly distributed on the impeller rear cover plate along the circumferential direction and extend to the rim of the impeller rear cover plate.

Furthermore, the back blade segment is divided into an A-type back blade segment and a B-type back blade segment, one end surface of the A-type back blade segment is a concave arc curved surface and is used for connecting the side surface of the cylindrical step, and the other end surface of the A-type back blade segment is a plane and is used for connecting the B-type back blade segment; the two end faces of the B-type back blade segment are planes and are used for connecting the A-type back blade segment and the B-type back blade segment or connecting the two B-type back blade segments.

Furthermore, each positioning rib is provided with an A-type back blade segment and a plurality of B-type back blade segments, the A-type back blade segment is located at a position close to the cylindrical step, and one surface, close to the cylindrical step, of the A-type back blade segment is an inwards concave arc curved surface.

Further, the A-type back blade segment and the B-type back blade segment are consistent in length and have the length of 0.02D-0.05D, wherein D is the diameter of the impeller back cover plate at the rim.

Further, the lower end faces of the A-type back blade section and the B-type back blade section are provided with channels, the width and the height of each channel are matched with the positioning ribs, the upper end faces of the channels are provided with through holes, bolts are connected with the positioning holes after passing through the through holes, and the relative positions of the sections and the impeller rear cover plate are fixed.

Further, the distance between the positioning holes corresponds to the back blade segment length.

Further, the radius of the side surface of the cylindrical step is consistent with the radius of the curved surface of the A-type back blade section, and the height of the cylindrical step, the height of the A-type back blade section and the height of the B-type back blade section are consistent.

Further, the number of the positioning ribs is 5-7.

According to the back blade of the sectional centrifugal pump, the back blade is formed by combining a plurality of sections, and the length of the back blade can be adjusted by using different numbers of back blade sections, so that the purpose of manually adjusting the length is achieved. In the actual use process, the required pressure sealing value can be calculated according to the inner cavity of the centrifugal pump and the atmospheric pressure difference, the pressure sealing capacity of the back blade needs to be adjusted, and the back blade is assembled by selecting the proper number of the segments, so that the two-way sealing for preventing liquid leakage and air from entering is realized.

Drawings

FIG. 1 is a schematic view of a segmented centrifugal pump back vane of the present invention;

FIG. 2 is a schematic view of the back shroud of the impeller;

FIG. 3 is a cross-sectional view of the back shroud A-A of the impeller;

FIG. 4 is a cross-sectional view of the positioning rib B-B;

FIG. 5 is a schematic view of the A-type back blade segment;

FIG. 6 is a schematic view of the B-type back blade segment;

FIG. 7 is a cross-sectional view of the back blade segment C-C.

The impeller comprises an impeller rear cover plate 1, a cylindrical step through hole 2, a positioning rib 3, a positioning hole 4, a 5-A type back blade section, a cylindrical step 6, a 7-B type back blade section, a bolt 8 and an impeller rear cover plate rim 9.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The impeller backplate 1 is part of the impeller and rotates with the impeller at the usual speeds of 980 rpm, 1450 rpm and 2900 rpm. As shown in fig. 1, the back blade of the segmental centrifugal pump mainly comprises an impeller back cover plate 1, an a-type back blade segment 5 and a B-type back blade segment 7. With reference to fig. 2 and 3, a cylindrical step 6 is disposed at the center of the impeller back cover plate 1, the outer diameter of the cylindrical step 6 is R, the range of values is 0.15D-0.2D, the height of the cylindrical step 6 is 0.05D, and D is the diameter of the impeller back cover plate rim 9. The center of the cylindrical step 6 is provided with a through hole 2 which is convenient for penetrating through the rotating shaft and fixing the relative position of the impeller and the rotating shaft. The rotating shaft penetrates through the through hole 2 and is fixed with the impeller rear cover plate 1 to drive the impeller to rotate. The radius of the through hole 2 is R, and R is 1.3R-1.4R.

Referring to fig. 2 and 4, the impeller back cover plate 1 is provided with a plurality of positioning ribs 3, the height of each positioning rib 3 is 0.025D, the width of each positioning rib is 0.025D, and the positioning ribs 3 are distributed along the radial direction and extend from the side of the cylindrical step 6 to the rim 9 of the impeller back cover plate. The positioning ribs 3 are provided with positioning holes 4, and the distance between the positioning holes 4 is consistent with the length of the back blade section.

As shown in fig. 5, one of the two end faces of the a-type back blade segment 5 is a plane and is a concave arc curved surface, and the radius of the curved surface is R, which is equal to the radius of the side surface of the cylindrical step 6. When the a-type back blade segment 5 is connected with the side of the cylindrical step 6, a seamless connection is achieved.

As shown in fig. 6, both end faces of the B-type back blade segment are planar and are used to connect the a-type back blade segment 5 and the B-type back blade segment 7, or to connect the two B-type back blade segments 7. The width of the A-type back blade segment 5 and the width of the B-type back blade segment 7 are both 0.05D, the length of the A-type back blade segment is 0.02-0.05D, when the adjusting precision required by sealing is high, the length of the A-type back blade segment is small, and when the adjusting precision required by sealing is low, the length of the A-type back blade segment is large.

Fig. 7 is a schematic C-C cross-sectional view of the a-type back blade segment 5, the B-type back blade segment 7, having a height of 0.05D, corresponding to the cylindrical step 6, and when the a-type back blade segment 5 is connected to the side of the cylindrical step 6, a smooth connection is achieved. The lower end face of the back blade segment is provided with a channel, the width of the channel is 0.025D, the height of the channel is 0.025D, the channel is consistent with the positioning ribs 3, and when the back blade segment is placed on the positioning ribs 3, the back blade segment can slide along the radial direction to adjust the relative position. The upper end face of the back blade section is provided with a through hole, the bolt 8 is connected with the positioning hole 4 after passing through the through hole, and the relative position of the back blade section and the impeller rear cover plate 1 is fixed.

A single A-type back blade segment 5 and a plurality of B-type back blade segments 7 are assembled with positioning holes 4 in positioning ribs 3 through bolts 8 and fixed on the positioning ribs 3 on an impeller rear cover plate 1 to form a segmented back blade, and the length of the back blade can be adjusted by additionally installing or disassembling the B-type back blade segments. A plurality of sectional back blades can be arranged on the impeller rear cover plate 1, the number range is usually 5-7, namely the number of the positioning ribs 3 is 5-7, and the positioning ribs are uniformly distributed along the circumferential direction. The centrifugal pump is selected according to the centrifugal pump lift, when the centrifugal pump lift is high and high pressure is required to be sealed, the number of the sectional back blades can be large, and when the centrifugal pump lift is low and low pressure is required to be sealed, the number of the sectional back blades can be small.

The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.