Pressure relief valve - WATER RESISTANT VA - COMPREHENSIVE SOLUTION FOR WATER PHENOMENON VA - WATER HAMMER. 
I - The limitations when used to absorb water hammer valve. 
 
As discussed in Part I, and the phenomenon of water - water hammer causing serious impacts not only the plumbing system that is capable of specifically destroying the impeller. And the simplest solution to mitigate the impacts of water phenomenon and it is designed to push tube system consists of one-way valve springs form, safety valves - pressure relief valve and the absorption of water hammer. However, this solution only mitigate the effects of water and phenomena and passive but can not eliminate the phenomenon and water. Therefore, this measure has some drawbacks follows: 
             First, from system design diagram shows to reduce water hammer phenomenon need to install a water hammer valve absorption (the number of valves depending on the level of impact of water hammer phenomenon). In addition, the system must be installed according to the broken line to facilitate the installation of this valve to increase the level of pressure loss due to pipe structure. 
             Second, after a sudden stop pump water column pressure is lower than the static pressure in the pipe will create an upside-down in water pressure and the water pressure acting on one-way valve off the wings to form valve springs closed. Normally, one-way current valve springs form capable of PN 16/10 bar pressure which means one-way valve springs form can only operate normally head back pressure acting on the opposite wing van of about 10 bar (100m equivalent) or less. So the building has 25 floors in height of water column pressure threshold in contrast to the safe operation of the one-way valve so quickly ruin the 1-way valve. At that time, if not one-way valve replacement operation efficiency of this system will not work. 
             Third, after the water column down to meet one-way valves in creating a thrust backwards and the conflict this pressure is absorbed slowly through the valve at absorbing the pressure mounted on the valve 1 pm . Therefore, the upper stage pipeline valves 1 pm to absorb water hammer valve above the still very strong shaking will be reduced through the absorption of the pressure relief valve on the shock side. In case of conflicting pressures pushing the safety limits safety valve will automatically open to discharge the pressure. This shows that this system works completely passive and can only mitigate the effects of water hammer phenomenon. 
 
             To address the phenomenon of radical and water - water hammer today people use pressure relief valves - Anti-collision (Quick pressure relief valve control) is referred to Van and waterproof. As its name implies, this valve line is used to prevent water and phenomena - water hammer in an active way by predictable phenomena and occur when the water pump stops working suddenly. 
           
             II - Principle of operation of water control valves and 
Pressure relief valve - and anti-80Q RAF used to eliminate the surge wave of water hammer phenomenon. Water hammer phenomenon occurs when the pump stops working abruptly or a valve on the main pipe is closed too quickly, then there will be a rapid magnifying section followed by low pressure reverse phase high pressure recovery. A series of pressure waves, each wave include the switch between low pressure and high pressure is created within seconds. 
RAF valves controlled by hydraulic operating pressure on the pipeline. Valve assemblies (pilot) to control pressure. In terms of spindle normal pressure, pressure relief valve - water resistant and completely sealed. Valve will open in the event of planned water phenomenon and will occur after the main pipe pressure is higher than the preset pressure and will continue until the pressure oscillation phenomenon in the pipe no longer .
 
 
             1 - Principle of operation of the pressure relief valve - Waterproof and RAF 80Q 
 
 
             Pressure valves - hydraulic water resistant and forms RAF operates on mains pressure and is controlled by the control valve (pilot). Control units consist of a spring membrane control. Waterproof and normal valve closed only when the pipe pressure increase above the preset limit control valve and the control will automatically open. The phenomenon of water and started to happen when there is a relative drop in pressure in the main pipe and then control valve will automatically open. After pressure waves rotating in opposite columns, valves and control are still open and reduce pressure discharge water column thereby mitigate the effects of head. 
          2 - How to adjust the pressure relief valve - water resistant and 
 

Adjusting: 
Use the needle valve to control the speed of operation of the pressure relief valve - and waterproof. Adjust the threshold settings of the control units of low pressure and high pressure control units by turning the adjustment screws.