CN204436854U - There is the efficient centrifugal pump of energy positive feedback groove structure - Google Patents

Abstract

The utility model discloses a high-efficiency centrifugal pump structure with energy positive feedback grooves. Through the unique feedback groove structure, the fluid leaking from the gap between the seal ring of the centrifugal pump and the impeller is transformed into a beneficial process jet. , positive feedback to the impeller suction port, pressurizing the fluid here, greatly improving the volumetric efficiency of the centrifugal pump. At the same time, since the negative disturbance caused by the leakage jet to the suction fluid is eliminated, the cavitation phenomenon of the centrifugal pump can be reduced or eliminated, the running noise can be reduced, and the overall efficiency of the centrifugal pump can be improved.

Description

High Efficiency Centrifugal Pump with Energy Positive Feedback Groove Structure

technical field

The invention relates to the technical fields of fluid mechanics and fluid machinery, and more specifically relates to a high-efficiency centrifugal pump using a closed impeller and having a special energy positive feedback groove structure.

Background technique

Centrifugal pumps are widely used in fluid machinery, and efficiency improvement has always been a research object. Among them, the fluid leaks from the high-pressure area of the pump to the low-pressure area through the sealing gap, resulting in a loss of volumetric efficiency, which is a technical problem in the pump industry. According to published literature on centrifugal pump design, the volumetric loss efficiency of centrifugal pumps is between 2% and 6%. According to the principle of fluid mechanics, the leakage of gap fluid is proportional to the pressure difference and has a cubic relationship with the size of the gap. Therefore, in actual production practice, the loss caused by the leakage of the seal ring of the centrifugal pump is much higher than the theoretical value. Especially on low specific speed pumps and pumps that have been worn due to long-term use, it is particularly obvious, even reaching more than 10%.

In addition, the fluid leaking through the sealing gap has a high velocity, which belongs to the category of jet flow in fluid mechanics. It not only causes the volume loss of the fluid in the high-pressure area, but also negatively disturbs the fluid form at the impeller suction port, which further aggravates the energy loss. , induce cavitation and noise in the pump, and reduce the overall efficiency of the centrifugal pump.

In the current centrifugal pump technology, there is still a lack of an effective method for utilizing the leakage jet energy, as shown in Figure 1. The direction of the leaked fluid is perpendicular to the axis of the impeller, which strongly disturbs the shape of the suction fluid and reduces the overall efficiency of the centrifugal pump. The usual traditional approach is, first, to control the gap between the impeller and the sealing ring within a reasonable range, such as taking a value of 0.2% D ("D" is the diameter of the impeller suction port), and the absolute value is between 0.3-0.8mm. The volume loss of the pump is controlled within the allowable range. The second is to adopt a labyrinth gap structure to achieve the purpose of increasing fluid leakage resistance, reducing leakage, and controlling volume loss.

Check Chinese patents, among the patented technologies that have been published, the utility model patent "A water pump mouth ring sealing device and the mouth ring used for the device" (application number CN201320499236) discloses a centrifugal pump with flow diversion and reduced leakage The pump port ring device (as shown in Figure 2) partially solves the above technical problems. Its technical feature is to use a grooved sealing ring to wrap the lip of the impeller suction port, which plays two roles: one is to guide the leaked fluid back to the impeller suction port and keep it in the same direction as the suction direction, taking advantage of the leaking fluid Speed head; second, due to the U-shaped structure of the sealing gap, the sealing length is increased, thereby reducing the leakage. This increases the volumetric efficiency of the centrifugal pump.

However, this technology still has unavoidable defects, that is, a part of the mouth ring protrudes into the impeller suction port, occupies part of the flow channel space, and disturbs the flow of the normal suction fluid at the end, thereby increasing the hydraulic loss; at the same time Since the mouth ring and the impeller suction lip form a long U-shaped sealing gap, the hydraulic friction loss of the leakage fluid is greatly increased, thereby weakening the utilization efficiency of the leakage fluid velocity head; third, due to the mouth ring and the impeller inlet lip The multi-faceted cooperation, the processing technology is more complicated, as shown in Figure 2.

Contents of the invention

The purpose of the present invention is to provide a structure that eliminates or reduces the volume loss of the centrifugal pump, and at the same time converts the harmful leakage jet into a process jet that is beneficial to improve the performance of the centrifugal pump, and skillfully solves the low volume caused by the internal leakage of the existing centrifugal pump Efficiency and leakage jet negatively disturb technical issues; at the same time, by adjusting the size of this process jet, the cavitation phenomenon of the centrifugal pump can be reduced or eliminated, and the overall performance of the centrifugal pump can be improved.

To achieve the above object, the technical scheme adopted in the present invention is as follows:

A centrifugal pump energy positive feedback groove structure, as shown in Figure 3. In the low-pressure area of the pump, corresponding to the outside of the sealing gap between the impeller and the mouth ring, an energy positive feedback groove structure (hereinafter referred to as "feedback groove") is set up, and the leakage jet generated by the sealing gap of the mouth ring is introduced from the side of the feedback groove. After reflection, it is exported from the side close to the flow channel, thereby changing the direction of the leakage jet, making it consistent with the direction of the fluid sucked into the impeller port, and pressurizing the fluid sucked by the centrifugal pump.

The parts shown in the figure are:

1 - impeller

2——Pump casing

3——Sealing ring

04 - high pressure area

05 - low pressure area

06 - mouth ring seal gap

07——Leakage jet

08——Feedback ditch

For the present invention, it needs to be further explained that:

(1) The shape of the cross-sectional profile of the feedback groove 08 is preferably a circular arc shape, or other combined shapes, such as isosceles trapezoidal, parabolic, etc., but there is only one purpose, which is to change the direction of the leakage jet 07 so that it Consistent with the direction of the suction fluid at the impeller inlet;

(2) The feedback groove 08 can be processed on the pump casing 2, or it can be processed on the widened sealing ring 3, as shown in Figure 4; the surface of the feedback groove should be smoothed to ensure good hydraulic efficiency;

(3) The setting of feedback groove 08 will not affect the diameter of the suction channel of the centrifugal pump, so the position of the reflection groove is kept an axial distance a from the suction inlet of impeller 1, and the direction of the feedback jet is kept at a small incident angle from the axial direction of the impeller θ; in order to ensure that the feedback jet 07 does not collide with the end surface of the suction port of the impeller 1;

(4) The function of the mouth ring seal gap 06 is no longer simply to ensure the reduction of leakage sealing and ensure the operation of the impeller, but has evolved into a process channel with energy positive feedback function. Its original design idea of trying to increase resistance has been transformed into Control the size of feedback flow and how to reduce hydraulic loss. Therefore, the gap sealing surface formed by the mouth ring 3 and the impeller 1 should be smoothed;

(5) The scope of application of the present invention includes all centrifugal pumps and air centrifugal compressors using closed impellers.

The present invention has the following beneficial effects:

(1) The energy positive feedback groove structure is set at the suction port of the centrifugal pump, which basically eliminates the volume loss caused by leakage, and increases the design efficiency of the pump by about 2%-8%;

(2) The smooth treatment of the counter ring, impeller sealing surface and reflection groove can further reduce the fluid friction loss of the centrifugal pump and improve the overall efficiency by about 0.5%-1%;

(3) The efficiency change of the pump is no longer sensitive to the wear of the mouth ring, so that the centrifugal pump can maintain a high efficiency state for a long time;

(4) Appropriately adjusting the size of the sealing gap, that is, adjusting the size of the positive feedback flow, can adjust the overall performance of the centrifugal pump, such as improving the cavitation characteristics of the centrifugal pump, reducing operating noise, vibration, etc., and the overall efficiency can be increased by 1%-2% about;

(5) Adding feedback groove structure does not change the overall structure of the existing pump body, and the processing is simple, which is convenient for large-scale promotion and implementation. The resulting energy-saving effect of the centrifugal pump (comprehensive efficiency increase 4%-11%) is very considerable, and the social and economic benefits are remarkable.

Description of drawings

Shown in the attached image are:

Figure 1——A general structural schematic diagram of a water pump port ring sealing device in the prior art

Fig. 2 - a schematic diagram of the preferred structure of the invention of application number CN201320499236

Figure 3 - Schematic diagram of the structure of the high-efficiency centrifugal pump with energy positive feedback groove structure of the present invention

Fig. 4 - a kind of realization form of the present invention, the structural schematic diagram of the efficient centrifugal pump of the seal mouth ring with feedback groove

Detailed ways:

The structure of the present invention is simple, and general engineers and technicians in the industry can grasp the design idea and implement the present invention in various ways.

The preferred embodiment 1 is shown in Figure 3. On the pump casing 2 and the front end of the inlet of the impeller 1, a circular arc positive feedback groove structure 08 is processed, and the angle θ between the positive feedback jet and the axis is determined to be between 5-10° (also It is the angle between the tangent direction of the end arc and the axis center derived from the feedback groove); the distance a between the feedback groove 08 and the end surface of the impeller suction port needs to be determined according to the thickness of the impeller lip; the feedback groove cross-sectional line type is recommended Use the arc line type, and the surface should be smoothed.

Another preferred solution, as shown in Figure 4, is to make the feedback groove structure on the sealing ring, which is more suitable for the fluid delivery centrifugal pump containing solid particles in the medium. When this composite sealing ring is worn to a certain extent, A new collar can be quickly replaced without repairing the pump body.

Claims (4)

1. A high-efficiency centrifugal pump with energy positive feedback groove structure, which is characterized in that an energy positive feedback groove is set on the outside of the sealing gap between the impeller (1) and the mouth ring (3) in the low pressure area (05) of the centrifugal pump Groove Structure (08). 2. The high-efficiency centrifugal pump with energy positive feedback groove structure according to claim 1, characterized in that the cross-sectional profile of the energy positive feedback groove structure (08) has a groove shape, including circular arc, trapezoid and parabola shape. 3. The high-efficiency centrifugal pump with energy positive feedback groove structure according to claim 1, characterized in that the position of the energy positive feedback groove structure (08) is in the low pressure area of the centrifugal pump, including on the pump casing (2) It is processed and inlaid on the mouth ring (3). 4. The high-efficiency centrifugal pump with energy positive feedback groove structure according to claim 1, characterized in that the axial position of the energy positive feedback groove structure (08) maintains an axial distance a from the impeller (1), and the feedback The jet (07) maintains a small incident angle θ with the impeller axis to ensure that the feedback jet (07) does not collide with the end surface of the suction port of the impeller (1).