Installing a hydrocyclone on an incline – Drivers and considerations

Why choose incline installation? 

• Most obvious – space constraints. In an existing concentrator plant, the building footprint and height are already set.  Hydrocyclones typically sit at the top of the grinding or filtration circuit in the concentrator plant, and so any new hydrocyclone cluster must fit into the available head height.  Designing the cluster with inclined hydrocyclones would eliminate some extra height that would be there compared against a hydrocyclone cluster with vertically-installed hydrocyclones. If no additional retrofit work is required to install this new hydrocyclone cluster into the existing space, this would be cost savings. 

• Increase the cut size - One would consider operating a hydrocyclone at an angle to increase the cut size. The gravity coefficient pulling particles to the underflow is not as strong when operating a hydrocyclone at an angle, and so the operating pressure coefficient is able to overcome gravity and force some larger middling particles to overflow.   

• Decrease the fines bypass - A decrease in fines bypass can also be a result when operating a hydrocyclone on an incline.  In addition to the larger middling particles, the pump pressure will “push” more water to the overflow compared against a vertically installed hydrocyclone.  Fine material will report with the water. 

As a negative, a reduction in separation efficiency can occur when operating at an angle. Instead of fine particles incorrectly reporting to the underflow, coarse particles can incorrectly report to the overflow.  This might not be detrimental to hydrocyclone performance but instead is something to be aware of and monitor. 

What to keep in mind 

After identifying the drivers, there are several key considerations that must be taken into account when installing a hydrocyclone on an incline. Here are three important considerations:  

• Hydrocyclone Design: The design of the hydrocyclone is another crucial consideration when installing it on an incline. The hydrocyclone diameter / size, cone length, and vortex finder : apex ratio may need to be adjusted to accommodate the incline. The inlet and outlet arrangements should be designed to ensure that they are not affected by the incline and do not create any backpressure or turbulence. Proper design can ensure that the hydrocyclone functions optimally and achieves maximum separation efficiency. 

• Hydrocyclone Wear Performance: Proper installation and maintenance are critical to the hydrocyclone's performance and longevity. Additionally, regular maintenance and cleaning are essential to ensure that the hydrocyclone remains free of blockages and operates at peak efficiency.  Wear life can be accelerated at the apex / spigot without as much water as lubricant in this area.  When the spigot and cone wears too much, this impacts the process performance negatively. A well-maintained hydrocyclone can help to prevent costly downtime and repairs and ensure that it functions effectively for years to come. 

• Cluster Design and Maintenance: When hydrocyclones are required to be installed on angle, the hydrocyclones overlap each other (apex of one hydrocyclone is underneath the head assembly of the adjacent hydrocyclone) around the radial distributor. This will make it more difficult to access the apex / spigot of each hydrocyclone. To perform maintenance then, it is required to remove the hydrocyclone from the cluster. Considering center of gravity of each cyclone during the lift will be difficult with the lower cone and apex underneath the cyclone next to it.  At the same time, launder volume and weight can be reduced because the angle of the hydrocyclones can point the underflow back towards the center of the cluster.  

Installing a hydrocyclone on an incline requires careful consideration of several critical factors. By taking into account the incline angle, hydrocyclone design, and installation and maintenance requirements, it is possible to ensure optimal performance and efficiency from the hydrocyclone.  

With any solution, it is advisable to consult with a qualified engineer or specialist to ensure that all necessary considerations are taken into account during the installation process.