Technical Articles
The valve selection of waterworks (Part Two)
Posted: 07/20/2018 10:47:38  Hits: 14
Valves used for filters

The most common filter is a four-valve filter, which is also the most basic configuration of the filter. No matter what kind of filter, there are at least four types of valves, including inlet valves, drain valves, flush valves and clean water valves. Of course, there are also filters with five valves, six valves and even seven valves, and they are equipped with air-operated valves, initial-filtered water valves and with inlet valves. The butterfly valve is usually selected for flush valves and clean water valves based on the structure of the valve. The main reason is that the clean water valve and the flush valve are installed on the pipe in the pipe gallery. The clean water valve needs to be frequently adjusted, and the flush valve needs to control the fluid flow. The gate valve is usually selected for the inlet valve and the drain valve. The diameter of the flush valve should be  larger than that of the clean water valve. The diameter of the flush valve is basically between DN600 and DN800, while the diameter of the clean water valve is between DN400 and DN600. From the point of view of control methods, these four types of valves are electrically controlled or pneumatically controlled. However, the clean water valve must have an adjustable intelligent control mode, which is consistent with the requirements of the inlet valve of the filter.
 
Valves used for pump houses

The valves in the pump room are mainly the inlet valve, the outlet valve, the service valve and the check valve on the pump unit. The first three valves basically use butterfly valves, the difference is the control mode. The inlet valve and the service valve only need manual valves, because one of them is always in the open state and the other one is often in the closed state. The outlet valve needs to be opened and closed every time when the pump is started and stopped. If the outlet valve needs to be used for adjusting the fluid so as to make the pump have different working conditions and to meet the requirement. The outlet valve also needs to be controlled by the intelligent control device. Reversing flows and water hammers should be prevented for the check valve. Usually, the silent check valve or the slow-closing check valve with micro-resistance is used. Multi-function valves are sometimes used for letting liquid out and reversing flows.