CN101251123A - Centrifugal pump impeller as well as cutting method thereof - Google Patents

Abstract

The invention relates to a centrifugal pump impeller and a cutting method thereof. Under the conditions that pump lift is greater (H is more than H1), while flow rate Q is approximately equal to Q1, the invention can realize independent control of flow rate and pump lift within a certain scope. The invention adopts the following structure: the vane outer edge of a cutting impeller has an incision which is in the shape of an isosceles triangle; the height h of the isosceles triangle is as follows: H is equal to (1-f<k> (H1/H)) D, while the base b is equal to the breadth of the front cover board and the back cover board of the impeller. The centrifugal pump impeller can ensure that rated base flow is invariant and that lift is reduced; moreover, the sizes between the front cover board of the impeller and a pump casing and between the back cover board of the impeller and the pump casing are invariant, and the energy loss inside a turbine caused by eddy flow is almost invariant, thereby solving the problem of efficiency reduction to a certain degree as compared with the prior impeller cutting method.

Description

A kind of centrifugal pump impeller and cutting method thereof

Technical field

The invention belongs to pump house later stage operating energy saving retrofit technology field, especially a kind of novel centrifugal pump impeller and cutting method thereof.

Background technique

Pump house in actual motion, usually generation systems need with the unmatched situation of pump performance, if lift of pump is greater than actual demand in system, can cause energy waste.

Fig. 1 is the schematic representation of existing cutting impeller method.All greater than actual demand, adopt following method to carry out reducing energy consumption at the flow of pump and lift usually:

(1) increases frequency variator, improve pump performance by the rotating speed of regulating pump;

(2) change blade angle and regulate lift and flow, but this method only is applicable to axial-flow pump and diagonal pumps, inapplicable radial flow pump---centrifugal pump;

(3) change inlet guide vane angle adjustment pump performance, this method is similar with the change blade angle;

(4) cutting impeller external diameter is suitable for specific speed and is not more than 350 series pump, and the bite of its front and rear cover plate and the bite of blade equate.

According to cutting law: Q/Q ₁=D/D ₁H/H ₁=(D/D ₁) ²

In the formula:

H---the lift before the impeller cutting;

Q---the flow before the impeller cutting;

H ₁---the lift after the impeller cutting;

Q ₁---the flow after the impeller cutting.

Can derive by the cutting law, if lift is reduced to H by H ₁, flow is reduced to Q by Q ₁After the cutting, lift of pump and flow all can descend, and this method is applicable to the situation that lift of pump and flow all can descend.

And at lift of pump H＞H1 bigger than normal and the situation of flow Q ≈ Q1, this method just is difficult to satisfy the demand.Do not cut, the blade outer rim of cutting impeller only, otch is an isosceles triangle.

Summary of the invention

The object of the present invention is to provide a kind of novel centrifugal pump impeller and cutting method thereof, can realize the independent control of flow and lift within the specific limits.

For achieving the above object, the invention provides a kind of centrifugal pump impeller, comprise forward and backward cover plate and the blade between front and rear cover plate, described blades height is lower than the height of described protecgulum and described back shroud.

The leaf margin of described blade is provided with leg-of-mutton opening.

The leaf margin of described blade is provided with the opening of isosceles triangle.

Described height h: $h=(1-r\sqrt[k]{\frac{H_1}{H}})D$

Wherein:

H is the lift before the impeller cutting;

Q is the flow before the impeller cutting;

H1 is the lift after the impeller cutting;

Q1 is the flow after the impeller cutting;

K is a coefficient, 1.2≤K≤2.5;

γ is a coefficient, 0.2≤γ≤1.5.

Described leg-of-mutton base b equals the width of the forward and backward cover plate of described impeller.

A kind of cutting method of centrifugal pump impeller, the blade of cutting impeller only, cutting blades height h: $h=(1-r\sqrt[k]{\frac{H_1}{H}})D$

Wherein:

H is the lift before the impeller cutting;

Q is the flow before the impeller cutting;

H1 is the lift after the impeller cutting;

Q1 is the flow after the impeller cutting;

K is a coefficient, 1.2≤K≤2.5;

γ is a coefficient, 0.2≤γ≤1.5;

The blade outer rim of described cutting impeller only, otch is a triangle, triangle height h: $h=(1-r\sqrt[k]{\frac{H_1}{H}})D$

Wherein:

H is the lift before the impeller cutting;

Q is the flow before the impeller cutting;

H1 is the lift after the impeller cutting;

Q1 is the flow after the impeller cutting;

K is a coefficient, 1.2≤K≤2.5;

γ is a coefficient, 0.2≤γ≤1.5;

Leg-of-mutton base b equals the width of the forward and backward cover plate of impeller.

Described otch is an isosceles triangle.

Compared with prior art, the present invention has the following advantages:

Centrifugal pump impeller provided by the invention and cutting method thereof, at lift of pump greater than actual demand, and under the situation that the flow of pump meets the demands substantially.Adopt the cutting method of centrifugal pump impeller of the present invention, the forward and backward cover plate of impeller does not cut, the blade outer rim of cutting impeller only, and otch is an isosceles triangle.Can realize that specified bare flow is constant, lift reduces.Size between impeller front and rear cover plate and the pump case does not change, and the energy loss that causes owing to eddy current in the turbine is constant substantially, so the more traditional impeller cutting method of the problem of decrease in efficiency makes moderate progress.

Description of drawings

Fig. 1 is the schematic representation of existing cutting impeller method;

Fig. 2 is the design sketch of existing cutting impeller method;

Fig. 3 is the schematic representation of the cutting method of centrifugal pump impeller of the present invention;

Fig. 4 is the design sketch of the cutting method of centrifugal pump impeller of the present invention;

Fig. 5 is the structural representation of centrifugal pump impeller of the present invention.

The primary component symbol description is as follows:

1 blade, 2 front shrouds

3 back shrouds, 4 cutters

5 low-speed flows, 6 high speed flow

7 volute chambers

Embodiment

Embodiment 1.

A kind of novel centrifugal pump impeller, the axle of its back shroud 3 go up to be installed blade 1, and blades height is than the low h of height of forward and backward cover plate, and front shroud 2 is enclosed within on the back shroud 3 after the assembling.

A kind of cutting method of novel centrifugal pump impeller, the forward and backward cover plate that keeps impeller does not cut, only the blade of cutting impeller.

The formula of cutting blade height h is: $h=(1-r\sqrt[k]{\frac{H_1}{H}})D$

Wherein:

H is the lift before the impeller cutting;

Q is the flow before the impeller cutting;

H ₁Be the lift after the impeller cutting;

Q ₁Be the flow after the impeller cutting;

K is a coefficient, 1.2≤K≤2.5;

γ is a coefficient, 0.2≤γ≤1.5.

Embodiment 2.

A kind of novel centrifugal pump impeller, the axle of its back shroud 3 go up to be installed blade, and leg-of-mutton opening is arranged on the leaf margin of blade, and front shroud 2 is enclosed within on the back shroud 3 after the assembling.

A kind of cutting method of novel centrifugal pump impeller, shown in Fig. 2,3, the forward and backward cover plate 2,3 that keeps impeller does not cut, the blade outer rim of cutting impeller only, otch is a triangle.

The formula of triangle height h is: $h=(1-r\sqrt[k]{\frac{H_1}{H}})D$

Wherein:

H is the lift before the impeller cutting;

Q is the flow before the impeller cutting;

H ₁Be the lift after the impeller cutting;

Q ₁Be the flow after the impeller cutting;

K is a coefficient, 1.2≤K≤2.5;

γ is a coefficient, 0.2≤γ≤1.5.

Leg-of-mutton base b equals the width of the forward and backward cover plate of impeller.

Embodiment 3.

A kind of novel centrifugal pump impeller, the axle of its back shroud 3 go up to be installed blade 1, and the opening of isosceles triangle is arranged on the leaf margin of blade 1, and front shroud 2 is enclosed within on the back shroud 3 after the assembling.

A kind of cutting method of novel centrifugal pump impeller, shown in Fig. 2,3, the forward and backward cover plate 2,3 that keeps impeller does not cut, the blade outer rim of cutting impeller only, otch is an isosceles triangle.

The formula of isosceles triangle height h is: $h=(1-r\sqrt[k]{\frac{H_1}{H}})D$

Wherein:

H is the lift before the impeller cutting;

Q is the flow before the impeller cutting;

H ₁Be the lift after the impeller cutting;

Q ₁Be the flow after the impeller cutting;

K is a coefficient, 1.2≤K≤2.5;

γ is a coefficient, 0.2≤γ≤1.5.

The base b of isosceles triangle equals the width of the forward and backward cover plate of impeller.

At lift of pump greater than actual demand, and under the situation that the flow of pump meets the demands substantially.Adopt the cutting method of centrifugal pump impeller of the present invention, the width of cutter 4 equals width, the height h foundation of the forward and backward cover plate of impeller $h=(1-r\sqrt[k]{\frac{H_1}{H}})D$ Calculate, between 4 on cutter and the forward and backward cover plate of impeller, cut along the radial direction of impeller.Can realize that specified bare flow is constant, lift reduces.

Fig. 2 and Fig. 4 are respectively the design sketch of the cutting method of existing cutting impeller method and centrifugal pump impeller of the present invention.The length of blade 1 is greater than the length of blade 1 in the existing impeller in the impeller, and when enlarging the rotation area, thereby the flow velocity that makes low-speed flow 5 and high speed flow 6 in the volute chamber 7 is greater than the low-speed flow 5 of existing volute chamber 7 and the flow velocity of high speed flow 6.

Fig. 5 is the structural representation of centrifugal pump impeller of the present invention.Adopt the cutting method of centrifugal pump impeller of the present invention, the size between impeller front and rear cover plate and the pump case does not change, and the energy loss that causes owing to eddy current in the turbine is constant substantially, so the more traditional impeller cutting method of the problem of decrease in efficiency makes moderate progress.

The survey electric current reached 58A after original hot water circulating pump parameter: Q=160m3/h, H=32m, N=22Kw, pump started half an hour, and actual power reaches 38Kw.

Transform back systematic parameter: Q=160m2/h, H=22, N=23Kw (measured current value 35A).

The above person only is preferred embodiment of the present invention, is familiar with the professional person of this skill such as. after understanding technological means of the present invention, natural energy is changed under instruction of the present invention according to the needs of reality.Therefore all equal variation and modifications of being done according to the present patent application claim still belong in the scope that patent of the present invention contains.

Claims (8)

1, a kind of centrifugal pump impeller comprises forward and backward cover plate and the blade between front and rear cover plate, it is characterized in that described blades height is lower than the height of described protecgulum and described back shroud.

2, a kind of centrifugal pump impeller as claimed in claim 1 is characterized in that, the leaf margin of described blade is provided with leg-of-mutton opening.

3, a kind of centrifugal pump impeller as claimed in claim 1 or 2 is characterized in that, the leaf margin of described blade is provided with the opening of isosceles triangle.

4, a kind of centrifugal pump impeller as claimed in claim 1 or 2 is characterized in that, described height h:

$h=(1-r\sqrt[k]{\frac{H_1}{H}})D$

Wherein:

H is the lift before the impeller cutting;

Q is the flow before the impeller cutting;

H1 is the lift after the impeller cutting;

Q1 is the flow after the impeller cutting;

K is a coefficient, 1.2≤K≤2.5;

γ is a coefficient, 0.2≤γ≤1.5.

5, a kind of centrifugal pump impeller as claimed in claim 2 is characterized in that, described leg-of-mutton base b equals the width of the forward and backward cover plate of described impeller.

6, a kind of cutting method of centrifugal pump impeller is characterized in that, the blade of cutting impeller only, and cutting blades height h: $h=(1-r\sqrt[k]{\frac{H_1}{H}})D$

Wherein:

H is the lift before the impeller cutting;

Q is the flow before the impeller cutting;

H1 is the lift after the impeller cutting;

Q1 is the flow after the impeller cutting;

K is a coefficient, 1.2≤K≤2.5;

γ is a coefficient, 0.2≤γ≤1.5;

7, the cutting method of a kind of centrifugal pump impeller as claimed in claim 6 is characterized in that: the blade outer rim of described cutting impeller only, and otch is a triangle, triangle height h:

$h=(1-r\sqrt[k]{\frac{H_1}{H}})D$

Wherein:

H is the lift before the impeller cutting;

Q is the flow before the impeller cutting;

H1 is the lift after the impeller cutting;

Q1 is the flow after the impeller cutting;

K is a coefficient, 1.2≤K≤2.5;

γ is a coefficient, 0.2≤γ≤1.5;

Leg-of-mutton base b equals the width of the forward and backward cover plate of impeller.

8, the cutting method of a kind of centrifugal pump impeller as claimed in claim 7 is characterized in that: described otch is an isosceles triangle.

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