Weir创新预旋技术如何减少叶轮前缘磨损

通过泵输送泥浆非常困难。它粗厚，有磨蚀性，含有多种固体。

由于颗粒的运动方式，泥浆中发现的粗大颗粒在泥浆泵叶轮叶片的前缘磨损中起主要作用。因为粗大颗粒的惯性意味着它们不遵循载液的流线，终导致大颗粒撞击叶片的前缘。

当泥浆流过管道时，较大的颗粒在入口底部沉降，并被流体拉动，而较小的颗粒则悬浮在泥浆内。颗粒在管道中的分离意味着离心泵的叶轮入口看不到同质的浆料混合物。

离心泵叶轮叶片的设计主要用于满足输入流并加速流体。当泥浆接近泥浆泵的叶轮时问题出现了，流动方向发生突变。细小颗粒随着流体从管道过渡到叶轮，但大颗粒不会。它们继续沿直线移动，当浆液通过叶轮时撞击叶片前缘。旋转叶片和进入颗粒之间的相对高速度导致叶轮前缘磨损。由于大颗粒的撞击而导致的叶片长度的损失导致泵性能减弱。终，泵将不能再产生需要的水头和流量，并且叶轮也需要更换。

我们做了什么?

在Weir矿业的矿物加工厂里，我们多次见证了叶轮前缘磨损问题，并希望提高Warman®研磨回路泵的耐磨性能。经过仔细检查，我们的工程团队设计了一个创新的解决方案，以减少对叶片前缘的冲击磨损 --- 配有预旋叶片的Warman® 管喉。

Warman® 管喉已获得专利，改变了入口管底部的粗糙固体相对于叶轮前缘的方向。

如何运作?

预旋叶片在泥浆进入叶轮之前改变浆料的流动，使其随着叶轮的旋转沿逆时针方向旋转。这就导致流动的旋转降低了叶轮叶片和浆体之间的相对速度。

管喉底部的预旋叶片的位置要比管喉其他位置的扭转角大。这是为更大颗粒提供更大的切向速度。以这种方式改变预旋角可以确保大颗粒和叶片前缘之间的相对速度被小化，同时保持流体在叶片上的正确冲击角度。

关于鼎恒石油

四川鼎恒石油是Weir SPM的授权代理商，若需要购买SPM产品或需要了解产品详细参数及相关疑问，可直接进入鼎恒石油官网咨询网站客服或者拨打销售热线18000522697。

四川鼎恒石油机械设备有限公司(http://www.dinghengot.com)是一家拥有进出口经营权，长期从事国内外石油天然气设备和配件的专业销售公司。鼎恒石油公司总部设在四川成都，在加拿大大不列颠哥伦比亚省成立了分公司。我公司与多家世界知名制造厂商建立了紧密的合作关系。

注：该文章由鼎恒石油编译，转发须注明出处。

附英文原文：

How to reduce impeller leading edge wear with our innovative pre-swirl technology

Transporting slurry through pumps is tough. It’s thick, abrasive and contains a wide range of solids.

The coarse, large particles found in slurry play a major role in the leading edge wear of slurry pump impeller vane due to the way the particles travel. Inertia of the large particles means they do not follow the stream lines of the carrier fluid. This results in the large particles impacting the leading edge of the vane.

When slurry flows through a pipe the larger particles settle towards the bottom of the inlet and are pulled along by the flow, whilst the smaller particles are suspended within the slurry. This segregation of the particles in the pipe means the impeller inlet of the centrifugal pump does not see a homogenous slurry mixture.

Centrifugal pump impeller vanes are designed to meet the incoming flow and accelerate the fluid. The problem occurs when the slurry approaches the impeller of the slurry pumps there is an abrupt change in flow direction. The small, fine particles follow the fluid as it transitions from the pipe into the impeller, but the large particles do not. They continue to move in a straight line, impacting the vane leading edge as the slurry moves through the impeller. The high relative velocity between the rotating vane and the incoming particles results in the impeller leading edge wear. Loss of vane length due to impacting of the large particles results in a loss of pump performance. Eventually the pump will no longer be able to generate the head and flow required for the duty and the impeller will need to be replaced.

What have we done?

At Weir Minerals, we witness this problem time and time again in arduous mineral processing plants, and wanted to improve the wear performance of our Warman® mill circuit pumps. After careful examination our engineering team devised an innovative solution to decrease the impact wear on the vane leading edge. The Warman® throatbush with pre-swirl vanes.

Our patented Warman® throatbush with pre-swirl vanes changes the direction of the coarse solids at the bottom of the inlet pipe relative to the impeller leading edge.

How does this work?

The pre-swirl vanes change the flow of the slurry, swirling it in an anti-clockwise direction, with the rotation of the impeller, before it enters the impeller. This induced rotation of the incoming flow reduces the relative velocity between the impeller vanes and the slurry.

Pre-swirl vanes at the bottom of the throatbush are positioned with a greater angle of twist than those elsewhere on the throatbush. This is to provide the larger particles with a greater tangential velocity. Varying the pre-swirl angle in this way ensures that the relative velocity between the large particles and the vane leading edge is minimized while at the same time maintaining the correct impingement angle of the fluid on to the vane.