A front cover structure for adaptively improving the cavitation at the impeller inlet

Abstract

The present invention relates to a front cover structure for adaptively improving the cavitation at the impeller inlet, which can adjust the radial and axial positions. The structure includes: a base, a front cover, and guide vanes; the base is detachably mounted on the front cover, and the mounting position of the base is a position that can move on the front cover. The guide vanes are mounted together with the base through a piston elastic component; the guide vanes are mounted on the front cover near the inlet side, and behind the guide vanes is a centrifugal pump impeller. The front cover structure for adaptively improving the cavitation at the impeller inlet provided by the present invention can adjust the radial and axial positions of the guide vanes, thereby achieving the improvement of the cavitation phenomenon at the impeller inlet.

Description

Technical Field

[0001] The present invention relates to a front cover structure, and more particularly to a front cover structure capable of adjusting the radial and axial positions of guide vanes. Background Art

[0002] As a general fluid machinery equipment, centrifugal pumps are widely used in fields such as urban water supply and drainage, agricultural irrigation, and cross-basin water transfer. With the continuous advancement of the socialization process, the working requirements for centrifugal pumps in various fields are becoming increasingly strict, especially under high-speed working conditions. The cavitation phenomenon under high-speed operation is the most common problem in the operation of centrifugal pumps. It not only causes the decline of the pump's hydraulic performance, but also generates vibration, noise, and even damages the flow components of the pump. Cavitation generally most commonly occurs at the inlet part of the impeller blades. Therefore, to ensure the safer and more stable operation of centrifugal pumps, it is very important to improve the inlet cavitation problem of the impeller. Summary of the Invention

[0003] Aiming at the above problems, the main object of the present invention is to provide a front cover structure capable of adjusting the radial and axial positions of guide vanes.

[0004] The present invention solves the above technical problems through the following technical solutions: A front cover structure for adaptively improving the inlet cavitation of an impeller, the front cover structure for adaptively improving the inlet cavitation of the impeller includes: a base, a front cover, and guide vanes; the base is detachably installed on the front cover, and the installation position of the base is a position that can move on the front cover, and the guide vanes are installed together with the base through a piston elastic component; the guide vanes are installed on the front cover near the inlet side, and behind the guide vanes is the centrifugal pump impeller.

[0005] In a specific embodiment of the present invention, the base is installed on the front cover through bolts, and multiple rows of bolt holes are provided in the part of the front cover for installing the base, and the base selects different bolt holes to change its position on the front cover.

[0006] In a specific embodiment of the present invention, the piston elastic component includes: a piston, a piston rod, an upper cavity spring, a lower cavity spring, and a piston cavity. The piston is located in the piston cavity. Taking the piston as the boundary, the piston cavity is divided into an upper piston cavity and a lower piston cavity. The piston rod includes a piston rod body and a piston rod connecting part; one end of the piston rod body is connected to the piston, and the other end is connected to the piston rod connecting part. An upper cavity spring is provided in the upper piston cavity, one side of the upper cavity spring is connected to the upper side of the piston, and the other side is connected to the upper side of the upper piston cavity. A lower cavity spring is provided in the lower piston cavity, one side of the upper cavity spring is connected to the lower side of the piston, and the other side is connected to the lower side of the lower piston cavity; the lower end of the piston rod is connected to the upper side of the piston, and the piston rod connecting part is the upper part of the piston rod; the piston rod connecting part is fixedly connected to the guide vane connecting part; the piston rod is a piston rod that can slide in the radial direction.

[0007] In a specific embodiment of the present invention, the upper cavity springs are divided into multiple groups and are evenly distributed around the piston rod in a circle.

[0008] In a specific embodiment of the present invention, the upper cavity springs are divided into two groups and are symmetrically distributed on both sides of the piston rod.

[0009] In a specific embodiment of the present invention, the lower cavity spring is a single group, which is distributed at the lower end of the piston, and the end combined with the piston is fixed at the center of the end face of the piston.

[0010] In a specific embodiment of the present invention, the upper cavity of the piston chamber is a closed structure, and the lower cavity of the piston chamber is a closed structure.

[0011] The positive and progressive effects of the present invention are as follows: The front cover structure for adaptively improving the cavitation at the impeller inlet provided by the present invention can adjust the radial and axial positions of the guide vanes, thereby achieving the improvement of the cavitation phenomenon at the impeller inlet. Description of the Drawings

[0012] Figure 1 It is a schematic structural diagram of the installation position of the present invention.

[0013] Figure 2 It is a schematic structural diagram of the present invention.

[0014] Figure 3 It is Figure 2 a partial enlarged view of

[0015] Figure 4 It is a cavitation performance curve graph of a specific embodiment in the present invention.

[0016] The following are the names corresponding to the reference numerals in the present invention:

[0017] In the figure: front cover 1, guide vane 2, base 3, piston 4, piston rod 5, upper cavity spring 6, lower cavity piston 7, piston chamber 8; piston rod connection part 501, piston rod body 502; upper cavity 801 of the piston chamber, lower cavity 802 of the piston chamber. Detailed Embodiment

[0018] The following presents the preferred embodiments of the present invention in conjunction with the drawings to elaborate in detail on the technical solutions of the present invention.

[0019] Aiming at the structural or technical deficiencies existing in current related products, the present invention provides a front cover structure that can improve the cavitation at the impeller inlet. The front cover of this structure has guide vanes with a certain shape at the inlet, and the guide vanes are placed at the front end of the impeller blades. This structure can adjust the radial and axial positions.

[0020] Figure 1 It is a schematic structural diagram of the installation position of the present invention, Figure 2 It is a schematic structural diagram of the present invention,Figure 3 is Figure 2 a partially enlarged view as shown in the above figure: An adaptive front cover structure for improving impeller inlet cavitation provided by the present invention includes a base 3, a front cover 1, and guide vanes 2; the base 3 is detachably installed on the front cover 1, and the installation position of the base 3 is a position that can move on the front cover 1, and the guide vanes 2 are installed together with the base 3 through a piston elastic component; the guide vanes 2 are installed on the front cover 1 near the inlet side, and behind the guide vanes 2 is a centrifugal pump impeller.

[0021] The base 3 is installed on the front cover 1 through bolts. The part of the front cover 1 for installing the base 3 is provided with multiple rows of bolt holes, and the base 3 selects different bolt holes to change its position on the front cover 1.

[0022] The piston elastic component in the present invention includes: a piston 4, a piston rod 5, an upper cavity spring 6, a lower cavity spring 7, and a piston cavity 8. The piston 4 is located in the piston cavity 8. Taking the piston 4 as the boundary, the piston cavity 8 is divided into a piston cavity upper cavity 801 and a piston cavity lower cavity 802. The piston rod 5 includes a piston rod body 502 and a piston rod connecting part 501;

[0023] One end of the piston rod body 502 is connected to the piston 4, and the other end is connected to the piston rod connecting part 501. An upper cavity spring 6 is arranged in the piston upper cavity 801. One side of the upper cavity spring 6 is connected to the upper side of the piston 4, and the other side is connected to the upper side of the piston cavity upper cavity 801. A lower cavity spring 7 is arranged in the piston cavity lower cavity 802. One side of the upper cavity spring 7 is connected to the lower side of the piston 4, and the other side is connected to the lower side of the piston cavity lower cavity 802; the lower end of the piston rod 5 is connected to the upper side of the piston 4, and the piston rod connecting part 501 is the upper part of the piston rod 5; the piston rod connecting part 501 is fixedly connected to the guide vane connecting part 201; the piston rod 5 can slide in the radial direction.

[0024] In the specific implementation process, in order to disperse the force, the upper cavity spring 6 is divided into multiple groups and evenly distributed around the piston rod 5. In the figure given by the present invention, the upper cavity spring 6 is divided into two groups and symmetrically distributed on both sides of the piston rod 5.

[0025] The piston cavity upper cavity 801 in the present invention is a closed structure, and the piston cavity lower cavity 802 is a closed structure.

[0026] The lower cavity spring 7 in the present invention is generally one group, distributed at the lower end of the piston 4, and the end combined with the piston 4 is fixed at the center of the end face of the piston 4.

[0027] In the present invention, the piston 4 provides radial movement and a fixing spring. The purpose of the spring-piston combination is to enable the guide vane to better adapt to the variable incoming flow conditions at the inlet under different working conditions. When the radial force is large, the guide vane will be compressed radially. At this time, the lower chamber spring 7 will provide a reaction force to ensure that the guide vane will not be pressed against the pump cover, resulting in frictional damage or stopping working. The upper chamber spring 6 is mainly used to cope with the circumferential force generated by the medium on the guide vane under different working conditions. Through the flexible torsional mechanical properties of the spring, it can adapt to different incoming flow conditions at the inlet, thereby realizing the self-adaptive function.

[0028] In addition, the improvement of cavitation in the present invention can also be achieved through the design of the guide vane 2, including the inlet and outlet installation angles, blade profile, wrap angle, etc. of the guide vane 2. The inlet part of the front cover plate 1 is provided with a guide vane 2 with a certain thickness and a twisted shape, and the guide vane 2 is placed at the front end of the impeller blade. When the centrifugal pump impeller rotates at a high speed, the front cover plate 1 drives the guide vane 2 to rotate at a high speed together. The high-speed rotating guide vane 2 will first give a certain kinetic energy to the working medium, increase the pressure, and then the pressurized working medium enters the impeller blade to continue running. In this process, the working medium undergoes preliminary pressure increase through the guide vane, so as to improve the cavitation phenomenon at the impeller inlet.

[0029] The change of the axial and radial positions of the guide vane 2 will have a significant impact on the cavitation effect. The structure of the present invention can change the axial distance by changing the axial connection position between the base 3 and the front cover plate 1.

[0030] During the rotation of the impeller, according to the different centrifugal forces generated at different speeds, the radial force received by the piston 4 will change, thereby driving the piston rod 5 to move radially, and thus changing the radial position of the guide vane 2.

[0031] To better illustrate the practicability of this structure, here taking a single-stage single-suction centrifugal pump with a specific speed n s = 165 as an example:

[0032] Flow rate Q = 300 m 3 / h; Head H = 20 m;

[0033] Using ANSYS (18.2) Fluent software, the cavitation performance of the impeller without a guide vane and with a guide vane at a certain fixed angle is calculated and compared respectively, and the cavitation performance curves as shown in the appendix Figure 4 are obtained.

[0034] As can be seen from the appendix Figure 4 : In the case without a guide vane, the calculated value of the cavitation margin of this pump by numerical simulation is 2.22 m, and in the case with a guide vane, the calculated value of the cavitation margin is 1.95 m. It can be seen from this that the front cover plate with a guide vane has the ability to improve the cavitation phenomenon at the impeller inlet.

[0035] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. An adaptive front cover structure for improving the cavitation at the impeller inlet, characterized in that: The front cover structure of the adaptive impeller inlet cavitation improvement can adjust the radial and axial positions of the guide vanes. The front cover structure of the adaptive impeller inlet cavitation improvement includes: a base, a front cover, and guide vanes; the base is detachably installed on the front cover, and the installation position of the base is a position that can move on the front cover. The guide vanes are installed together with the base through a piston elastic component; the guide vanes are installed on the front cover near the inlet side, and behind the guide vanes is the centrifugal pump impeller. The base is installed on the front cover through bolts. The part of the front cover for installing the base is provided with multiple rows of bolt holes, and the base selects different bolt holes to change its position on the front cover. The piston elastic component includes: a piston, a piston rod, an upper cavity spring, a lower cavity spring, and a piston cavity. The piston is located in the piston cavity. Taking the piston as the boundary, the piston cavity is divided into an upper piston cavity and a lower piston cavity. The piston rod includes a piston rod body and a piston rod connecting part; one end of the piston rod body is connected to the piston, and the other end is connected to the piston rod connecting part. An upper cavity spring is arranged in the upper piston cavity. One side of the upper cavity spring is connected to the upper side of the piston, and the other side is connected to the upper side of the upper piston cavity. A lower cavity spring is arranged in the lower piston cavity. One side of the lower cavity spring is connected to the lower side of the piston, and the other side is connected to the lower side of the lower piston cavity; the lower end of the piston rod is connected to the upper side of the piston, and the piston rod connecting part is the upper part of the piston rod; the piston rod connecting part is fixedly connected to the guide vane connecting part; the piston rod can slide in the radial direction. The lower cavity spring is a group, distributed at the lower end of the piston, and the end combined with the piston is fixed at the center of the end face of the piston. The upper piston cavity is a closed structure, and the lower piston cavity is a closed structure.

2. The front cover plate structure for adaptively improving the inlet cavitation of the impeller according to claim 1, characterized in that: The upper cavity spring is divided into multiple groups and evenly distributed around the piston rod.

3. The front cover plate structure for adaptively improving the inlet cavitation of the impeller according to claim 2, wherein: The upper cavity spring is divided into two groups and symmetrically distributed on both sides of the piston rod.

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