A sand separator is a device used to remove sand or sludge from fluid suspensions, typically water pumped from boreholes and wells. Most sand separation devices work by imparting a cyclonic flow pattern in the water that passes through them. This action spins the heaviest sand particles out of the separator, where they settle into collection chambers for later removal. This differentiates the sand separator from conventional filters and also makes it more reliable and easier to maintain. These devices fall into two basic categories: those located above ground and those situated in a pit.
Many well or well environments have sand contamination to one degree or another. This suspended sludge is not only undesirable from a health standpoint, it also wreaks havoc on pump parts, valves, plumbing and irrigation systems. Removal of suspended sand from well water can be accomplished using physical filters or by placing a sand separator in line with the pump discharge or suction pipes. Filters are very efficient at removing suspended sand from the water, but they are also subject to clogging and require considerable effort for cleaning and maintenance. Also, elements used as physical barriers in a filter are often very expensive.
The sand separator is a much simpler sand removal option in operation and requires less maintenance and less financial commitment to maintain. These devices make use of a rotating cyclone-like action within their housings to transmit a centrifugal force in the water that passes through them. Most sand separator units are closed, cylindrical devices and achieve cyclonic action by drawing water into the cylinder through inlet ports placed at a tangent to its linear axis. This causes the water to spin in a spiral pattern as it passes through the device.
The centrifugal force imparted to the suspension causes the heaviest sand particles to be thrown out of the tube, where they settle and collect. The clean water is then drawn from the cylinder to the discharge tubes. How collected sand is removed from the separator depends on which of the two basic types of device is being used. The first of these is the above-ground separator, which is usually easily accessible. This type of device has a purge valve at the bottom of the cylinder, allowing the sand to be manually washed out of the device at regular intervals.
The second type of sand separator is the in-well or submerged device located at the bottom of the well or hole, which is obviously not accessible. These separators feature an automatic, flexible valve at the bottom of the separator box. When a predetermined amount of sand is collected at the bottom of the cylinder, the valve automatically opens and the sand falls to the bottom of the well.