When sand slurry is prepared for a process it usually passes through a Vibratory Ball Mill. Vibratory ball mills are used for the grinding and mixing of sand slurry.
In this process hundreds of steel balls rotate within a sealed drum which contains perforations along its axis at set sizes. When the slurry particles reach the required size, the sand and silica mixtures fall through the perforations within the drum making them suitable for the next stage in production.
When a manufacturer of such equipment wanted a pump capable of handling a silica and slurry mixture undergoing preparation for transfer into another process, we knew the solution would need to be low maintenance, and provide longevity even though it was handling a vary abrasive element on a daily basis.
The customer manufactured such mills which were dispatched worldwide and it was important problems were not encountered across differing grades of sand or silica, that the pumps were of heavy duty design to avoid premature wear as it would be both costly and time consuming to resolve. Pumps would need to operate 24/7 so we wanted to ensure units did not require frequent maintenance or inspection.
Our customer required a highly reliable slurry feed pump to handle their silica sand mixture which at times could have a high percentage of dry content. This is an issue for most designs of pumps as they contain a mechanical seal which is lubricated and cooled by the process liquid. If enough liquid is not present then the seal can overheat leading to failure.
There are three ways to overcome this issue – using a complicated sealing quench system which is difficult to maintain and did not eliminate the risk, a packed gland which uses fluid to lubricate the packing and drips which again may require a cooling connection or utilise a seal less pump.
Our peristaltic pump range, also known as a roller or hose pump was selected as the solution for this application. An AMP16; our seal-less, compact ¾” peristaltic pump was supplied, capable of running dry indefinitely without incurring any damage to its internal components and designed to operate continuously if required.
Being seal-less meant the unit did not require liquid to cool a shaft seal as other pump technologies demand. It is excellent at handling cement, sand, and silica slurry mixes that are extremely dense, dry and abrasive.
Peristaltic pump design is one of the simplest pump technologies. Units contain a single hose connecting the inlet to the outlet, which is gently compressed via rollers or shoes guiding fluids from the inlet to the outlet. Fluids handled range from very thin oils to sludge, concrete or molasses.
Another feature of this design of pump is that its design is non clog meaning if any mixture sets or hardens within the unit, it is capable of generating enough pressure to clear this without damage to the pump.
Our solution included an integrated variable speed drive on the motor with forced cooling, this combination enabled our customer to operate the pump at incredibly low speeds, as low as 3 Hz and 1 RPM to be precise, meaning a capacity range of 5 -188 litres per hour and a maximum design pressure of 8 bar. Other designs of pumps often operate in excess of 200rpm (up to 200 times faster than our solution) to produce the same results greatly accelerating wear and abrasion.
As the first unit was for a smaller pilot plant, it enabled the customer to perform trials across a range of flows, and once the design is finalised as our range is modular in design there would be little change from the initial pilot version to the final machine meaning design changes are minimal.
As the motor size and speed can be changed to alter pump output with no change to the inlet and outlet pipework size or orientation, it meant in the future our slurry pumps can be utilised across various installations of equipment reducing variations in design, the associated number of spare parts kept on site, as not only do units only contain a single wearing hose but spares are interchangeable.
