The sandwasher is the heart of our product range which, among other equipment, consists of different augers and conveyors for the transfer of different sand containing material to and from the cleaning proces..
The sandwasher is available in different sizes being individually adapted to the customer’s needs and actual conditions in every project..
The sandwasher is built based on the experience of many years of operation on public and private waste water treatment plants where there is a requirement of separation organic and anorganic material.
The sandwasher is built to efficiently separate sand from manure or waste water and to wash the sand for reuse.
The mixed sand/manure effluent containing organic material is pumped into the hydro cyclone (2) via the tangential top inlet (1). At this stage, a first separation of sand and manure will occur by the effect of the hydro cyclone and the difference in specific weight between the sand and the manure. The manure leaves the hydro cyclone through the top overflow, whereas the separated heavier sand falls through the intlet (4) into the tank (6).
In the tank, the top mounted mixer with gear motor (5) will gently mix the manure and the sand, causing the sand to sink to the bottom and the manure/organic material to float to the surface at the level of the outlet (3) for separated sandfree slurry
The sand level at the bottom of the tank will slowly increase causing a higher power consumption of the mixer (5). At a certain level, the power consumption (kW) of the mixer reaches the setpoint ”start auger”, the auger (9) will start discharging sand to the washed sand storage (10) causing the power consumption (kW) of the mixer to decrease to its “stop auger” setpoint.
At the bottom of the tank, there is a sand flushing arrangement (7). This allows continuous flushing of the sand with water, thereby washing out the organic material and cleaning the sand. Pressure valves at each of the flushing pipes ensure to keep the pressure of the flushing effluent at the correct level.
During the operation periods of the sandwasher unit, separated slurry and washed out organic material as well as flushing water will continuously mount to the surface of the tank and be transferred out of the tank through the outlet (3).
On the tank, below the outlet (3) a further outlet with a blind flange is mounted. Occasionally, heavier sludge and organic material can accumulate at a level below the outlet (3) which can make it necessary to retrieve this media through this supplementary outlet. As an option, a valve (not shown on the below schematic drawing) can be mounted on this outlet.
At the lower end of the discharge auger (9), an emptying valve (8) is mounted, making it possible to completely empty the sandwasher of both sand and water. This function is necessary in connection with lowering the liquid level in the tank or for maintenance or cleaning of the unit.
If the sandwasher is delivered complete with a control panel from Stjernholm A/S, the washing process is controlled automatically by PLC and the operator can control/adjust the process via a local touch screen (11).