16 June, 2021
How to select washers for your M-Sand plant ?
SIVABALAN SELVARAJAN
ASSOCIATE HEAD, OPERATION
SIVABALAN SELVARAJAN
ASSOCIATE HEAD, OPERATION
The answer to the above raised question is five fold. Selection of washers depends on the following five conditions. They are
1. Space availability
2. Water availability
3. End Product requirement
4. Finance availability
5. Labour availability
Let us delve deep into each of the above five tenets for a better understanding.
Space Availability :
Modern day crushing and screening plants are so compact and modular such than a complete three stage crushing and screening plant is accommodated well within an area of 10,000 Sq. ft. Washers being a last stage in an aggregate processing plant, space constraints shall be taken into account so that there is enough availability for loading by haul trucks. Water recycling and equipment maintenance for conventional classifiers such as Bucket classifiers take up a lot of space due to its elongated design.
The spiral tub at the dorsal portion of the classifier is where the weir launder is fixed and eliminating the same from the design may allow coarse particles to report in the overflow. Further, the requirement of sedimentation tanks and corresponding pipelines will occupy space large enough, that could be a possible problem for plants operating in congested crusher hubs or within city limits. Advanced washers such as Envo washers are stacked up vertically such that, horizontal spacing is eliminated and the washers allow for operations in a compact space.
Lean design allows for above the ground feed points such that existing conveyor setups can be used, taking leverage of the available height. Here Envo washers are the most viable option.
Water Availability :
Washing Industry is dependent upon a resource that is so scarce such that the demands keep increasing day by day. Conventional washers such as Bucket classifiers and Screw classifiers are high water demanding equipment. An additional dewatering screen is always required to prevent additional water to go away in the output.
The biggest disadvantage of these equipments are the non-availability of options to control the amount of overflow that is discharged into the sedimentation tank. The overflow launder of the Screw classifier allows for so much of water to be wasted followed by the weir discharge launder of the Bucket classifiers.
Modern day washers such as Envo washers and Hydro washers have inbuilt valve mechanisms that provide options to control the amount of water going into the sedimentation pond, allowing remaining water to be recycled back into the sump. Water management solutions such as Nesans Fitch Series Thickeners operated in parallel with these washers allow for 90% of the water to be recycled and reused.
So we recommend Envo washers, Hydro washers installed along with Fitch thickeners for investors seeking to control water utilisation and planning to install plants in water scare areas.
End Product Requirement :
The number of grades of products exiting the washers play an important role in equipment selection. The sand industry has clearly moved away from single grade to dual grade and conventional washers such as Screw classifiers and Bucket classifiers can only produce a single grade of sand that is thoroughly washed.
Products are tweaked in the market to produce dual grades of sand which shall satisfy production expectations but not quality expectations. Advanced washers such as Envo washer and Hydro washer allow for sophisticated dual grades of sand. Coarse and fine sand produced from a split Dewatering screen can be used for concreting and plastering purpose respectively.
Moreover, material mixing mechanisms over the screen allows for controlling the gradation of the output product to pass relevant standards such as IS-383 (1970) for concrete and IS-1542(1992) for plastering. So we recommend hydrocyclone based Envo washer and Hydro washers for applications requiring more than a single grade of sand.
Finance Availability :
Every investor is concerned with the Return of Investment (ROI) and sand is one of the most promising investment tools. Ever increasing construction material demand has called for more demand for sand. Conventional washing equipment such as Bucket classifiers and Screw classifiers are low investment equipments.
They allow for an easy installation and running of the plant but the cost saved during the initial setup is washed away in the form of 30% overflow. Poor retention capacity of these equipment allows for saleable material to be wasted. However, if recent models such as Envo washer and Hydro washer are high initial investment equipment but their break-even period is even more sooner as compared to conventional washer.
So for customers who are looking for a cheap initial investment but cares less about the operating wastage, we recommend our SWD Series Bucket classifiers whereas, for customer who are flexible to extend their budget to reap benefits of higher ROI and break-even period, we recommend our SWE Series Envo washers.
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Labour Availability :
The last tenet in selecting the washer has a bit of human touch to it and it all comes down to the skill level of the operator and the labors he commands. Conventional washers demand less skilled labours for there are no big maintenance activities. They should be only aware of the wear in the bucket assembly and be cautious to change them in time. Whereas, advanced equipment demand for a decent skilled labor for its operation.
Better understanding or initial training of the operation and maintenance of slurry pump, Hydrocyclone and drives are required. That is why Nesans has taken these things into account while we designed our equipment. Advanced control systems now monitor vital parameters such as sump water level, inlet pressure of the Hydrocyclone and slurry flow rate such that even semi-skilled operators can operate there machines.
Conclusion :
Taking into account the above five tenets to select a suitable washer for the manufactured sand washing application, we have compiled below a brief representation of each of our washer models’ advantages and limitations.
| Washer | Space | Water | No of Products | Budget | Labour |
SWD-Series | ❌ | ❌ | ❌ | ✔ | ✔ |
SWF-Series | ✔ | ✔ | ✔ | — | ✔ |
SWE-Series | ✔ | ✔ | ✔ | — | ✔ |
T-Series | ❌ | ❌ | ❌ | ✔ | ✔ |
We recommend our SWF Series Envo washers and SWE Series Hydro washers
Envo Washer
Hydro Washer