Introduction to Swimming Pool Sand Filters
The sand filter features a relatively simple structure, incorporating a precision-engineered internal water distributor that prevents sand from escaping into the return flow. The external valve head allows for convenient switching between functions such as filtration and backwashing. The valve head is equipped with three ports-inlet, outlet, and waste-all connected via unions to facilitate rapid piping installation and disassembly. These unions are available in both metric and imperial standards to ensure compatibility with piping systems in different regions. The valve head connection functions are illustrated in the diagram on the right.
Pressurized water enters the tank and passes through the sand bed; the finely perforated water distributor prevents sand from entering the outlet while the sand bed filters out suspended particles. The filter is equipped with a valve head-commonly known as a multiport valve-that allows for easy control of water flow direction for rinsing and backwashing operations. Quartz sand, activated carbon, or even biochemical media can be used as the filtration material; if biochemical media is used, the unit can function as a biological filter.
Valve Head Function Descriptions
1. FILTER: Normal filtration operation.
2. BACKWASH: Flushes out accumulated debris from the filter.
3. RINSE: Flushes out debris remaining in the waste line.
4. RECIRCULATE: Circulates water without filtration.
5. WASTE: Discharges water directly without filtration.
6. CLOSED: Shuts off all filter functions.
Note: Always stop the water pump before changing the valve position.
