阅读说明：本技术 一种带护圈离心泵组合密封 (Centrifugal pump combined seal with guard ring ) 是由 王凯 鲍海峰 刘厚林 马皓晨 谈明高 王勇 董亮 于 2021-07-26 设计创作，主要内容包括：本发明公开的一种带护圈离心泵组合密封,涉及离心泵技术领域,所述带护圈离心泵组合密封为离心密封与迷宫密封的组合,通过在后盖板背面设置叶片,带动泄漏的流体旋转形成反压,实现离心密封。离心密封出口设计护圈,所述护圈在副叶轮出口处环绕布置,可以提高反压系数,提升密封性能、减少沿外径处动量交换和液体摩擦力矩,进而减小功率损耗。所述护圈与泵盖之间通过设置环形槽形成迷宫密封结构,进一步提升密封性能。该带护圈离心泵组合密封具有广泛的适用性,在离心泵密封设计中较高的实用价值。(The invention discloses a centrifugal pump combined seal with a guard ring, which relates to the technical field of centrifugal pumps. The centrifugal seal outlet is provided with a retainer which is arranged at the outlet of the auxiliary impeller in a surrounding manner, so that the back pressure coefficient can be improved, the sealing performance is improved, momentum exchange and liquid friction torque along the outer diameter are reduced, and further the power loss is reduced. A labyrinth seal structure is formed between the guard ring and the pump cover through the annular groove, and the sealing performance is further improved. The combined seal of the centrifugal pump with the guard ring has wide applicability and higher practical value in the seal design of the centrifugal pump.)

1. A centrifugal pump combined seal with a guard ring is characterized in that the mechanical structure of the seal comprises a rear cover plate, blades, the guard ring and a pump cover; the blades are located on the back face of the rear cover plate, the guard ring is located on the outer edge of the rear cover plate, and the pump cover is a part of the pump body.

2. The centrifugal pump combined seal with the retainer of claim 1, wherein the back cover plate, the blades, the retainer and the pump cover together form a centrifugal seal and a labyrinth seal, the centrifugal seal and the labyrinth seal together form a combined seal, the centrifugal seal is a non-contact dynamic seal, the blades drive liquid to rotate during operation, and the seal is realized by using the back pressure of the rotating liquid; the labyrinth seal is formed by an annular groove between the guard ring and the pump cover.

3. The centrifugal pump with shroud combination seal of claim 1, wherein said vanes are straight vanes or backward-curved vanes, and the vane outlet setting angle β₂30-90 degrees, the number of the blades z is 6-12, and the width of the blades delta is 0.01-0.03D_hubWherein D is_hubThe diameter of the rear cover plate is 1.0-2.0 delta of the height h of the blade, and the inner diameter D of the blade₁＝0.15～0.3D_hubOuter diameter D of blade₂＝0.8～0.98D_hubThe maximum pressure which can be balanced by the dynamic seal is as follows: and k is a back pressure coefficient, k is 0.8-0.9, rho is the density of the working medium, and omega is the rotating speed of the impeller.

4. The centrifugal pump combination seal with a retainer of claim 1, wherein the retainer is located on the back outer edge of the back cover plate and surrounds the back cover plate along its periphery, and the retainer has a thickness σ of 0.5 (D)_hub-D₂) Axial height h of retainer_c＝2.0～3.0h。

5. The centrifugal pump combined seal with the retainer of claim 1, wherein an axial gap psi between the rear pump cover and the blades is 0.2-1.0 h, an annular groove is formed in an end face and matched with the retainer to form a labyrinth seal structure, and the width of the annular groove is wideThe depth alpha of the annular groove is 1.0-2.0 sigma.

Technical Field

The invention belongs to the technical field of centrifugal pumps, and particularly relates to a centrifugal pump combined seal with a guard ring.

Background

Leakage is an undesirable phenomenon in which a medium, such as a gas, a liquid, a solid or a mixture thereof, passes from one space to another and is one of the three main sources of mechanical failure in modern equipment. The leakage not only causes energy waste, material loss and environmental pollution, but also even causes fire and explosion, directly endangers personal safety and brings huge economic loss. The pump is used as a fluid machine, the leakage problem is common, and in order to prevent or reduce the leakage of high-pressure liquid in the pump along the axial direction, sealing measures must be taken, wherein the most common measures are packing seal, mechanical seal and the like, but the packing seal has the defects of short service life and easy damage, and the mechanical seal has the problems of complex structure, high price and easy abrasion and failure during conveying of medium containing particles. The non-contact labyrinth seal and centrifugal seal can overcome the defects of packing seal and mechanical seal, and can be used for the transportation of corrosive media and particle-containing media under high-speed and high-temperature working conditions.

As pumps are gradually developed toward high speed, high pressure, and the like, which also makes pump seals highly reliable and long-life, non-contact seals such as labyrinth seals, centrifugal seals, and the like are receiving increasing attention.

Disclosure of Invention

The invention provides a combined seal of a centrifugal pump with a guard ring, which realizes the seal of the centrifugal pump through the combination of a labyrinth seal and a centrifugal seal.

The technical scheme adopted by the invention is as follows: a centrifugal pump combined seal with a guard ring is characterized in that the mechanical structure of the seal comprises a rear cover plate, blades, the guard ring and a pump cover; the blades are located on the back face of the rear cover plate, the guard ring is located on the outer edge of the back face of the rear cover plate, and the pump cover is a part of the pump body.

As a further scheme of the invention, the rear cover plate, the blades, the retainer and the pump cover of the centrifugal pump combined seal with the retainer form a centrifugal seal and a labyrinth seal together, and the centrifugal seal and the labyrinth seal form a combined seal together. The centrifugal seal adopts non-contact dynamic seal, the blades drive the liquid to rotate in the working process, and the back pressure of the rotating liquid is utilized to realize sealing. The labyrinth seal is formed by an annular groove between the guard ring and the pump cover.

As a further proposal of the invention, the centrifugal pump combined seal with the guard ring is characterized in that the blades are straight blades or backward-bent blades, and the outlet of the blades is provided with an angle beta₂30-90 degrees, the number of the blades z is 6-12, and the width of the blades delta is 0.01-0.03D_hubWherein D is_hubThe diameter of the rear cover plate is 1.0-2.0 delta of the height h of the blade, and the inner diameter D of the blade₁＝0.15～0.3D_hubOuter diameter D of blade₂＝0.8～0.98D_hubThe maximum pressure which can be balanced by the dynamic seal is as follows: and k is the back pressure coefficient k of 0.8-0.9, rho is the density of the working medium, and omega is the rotating speed of the impeller.

In a further aspect of the present invention, the centrifugal pump combined seal with a retainer is characterized in that the retainer is located on an outer edge of a back surface of the back cover plate and surrounds the outer edge of the back cover plate for one round, and a thickness σ of the retainer is 0.5 (D)_hub-D₂) Axial height h of retainer_c＝2.0～3.0h。

As a further proposal of the invention, the centrifugal pump with the guard ring is combined with a seal,the axial clearance psi between the rear pump cover and the blades is 0.2-1.0 h, an annular groove is formed in the end face and matched with the guard ring to form a labyrinth seal structure, and the width of the annular groove is equal toThe depth alpha of the annular groove is 1.0-2.0 sigma.

The invention has the beneficial effects that:

the sealing adopts a non-contact form, can overcome the defects of contact sealing, is particularly suitable for occasions which are difficult to be qualified by common sealing, such as high speed, high temperature, corrosive and solid particle-containing media transportation and the like, and has the characteristics of simple structure, reliable sealing and long service life.

The seal design combining labyrinth seal and centrifugal seal further improves the sealing performance and reliability and avoids axial leakage of the centrifugal pump.

The design of the retainer ring in the seal can improve the back pressure coefficient of the common centrifugal seal, improve the pressure sealing capacity, and simultaneously reduce the momentum exchange and the liquid friction torque along the outer diameter, thereby reducing the power loss.

Drawings

FIG. 1 is a schematic view of a combined sealing structure of a centrifugal pump with a guard ring;

FIG. 2 is a schematic view of a blade disc, blades and a retainer in a combined sealing structure of a centrifugal pump with the retainer.

Detailed Description

The invention will be further described with reference to the following figures and specific examples, but the scope of the invention is not limited thereto.

As shown in figure 1, the seal is formed by combining a centrifugal seal and a labyrinth seal and comprises a rear cover plate, blades, a retainer and a pump cover. The blades are located on the back face of the rear cover plate, the guard ring is located on the outer edge of the back face of the rear cover plate, and the pump cover is a part of the pump body. The centrifugal seal is a non-contact dynamic seal, the blades drive liquid to rotate in the working process, the seal is realized by utilizing the back pressure of the rotating liquid, and the labyrinth seal is formed by an annular groove between the guard ring and the pump cover.

As shown in fig. 2, a centrifugal pumpThe diameter of the impeller back cover plate is 260mm, the rated rotating speed is 2950rpm, the conveyed medium is sand-containing water, and the density is 1200kg/m³. The centrifugal sealing blade is a straight blade, and the outlet of the blade is arranged at an angle beta₂90 degrees, blade number z 8, blade width delta 5mm, blade height h 8mm, blade inner diameter D₁50mm, blade outside diameter D₂250mm, the maximum pressure P that can be balanced by the centrifugal seal is 0.77 MPa.

As shown in fig. 2, the guard ring is located at the outer edge of the back surface of the back cover plate, and surrounds the outer edge of the back surface of the back cover plate for a circle, the thickness sigma of the guard ring is 5mm, and the axial height h of the guard ring is_c16mm, the setting of protective shroud can improve back pressure coefficient, promotes sealing performance, reduces along outer diameter department momentum exchange and liquid friction torque, and then reduces power loss.

As shown in figure 1, the axial clearance psi between the rear pump cover and the blades is 3mm, the end surface is provided with an annular groove which is matched with the guard ring to form a labyrinth seal structure, and the width of the annular groove isThe depth alpha of the annular groove is 7 mm.

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.