Flucon - Model 200 - Automatic Control Valves
Control valves are designed to stabilize pressure, level and flow in a given water system. This type of valve operation may be hydraulic, electric or electronic. There are also electric-hydraulic and electronic-hydraulic combinations available, in remote monitoring and control systems it is recommended to use electric or electronic valves with hydraulic redundancy.
Flucon 200 is a hydraulically operated, diaphragm actuated globe type valve. The valve is composed by three major components; body, diaphragm assembly and cover. The diaphragm assembly containing the stem is fully guided at both ends. The diaphragm assembly is the only moving part and forms a sealed chamber separating the operation pressure from the line pressure.
The pilot system is modular type and the control pilots are made of stainless steel 316L, the way of operation is 'Integral Balanced Pressure', which means that changes in the upstream pressure will not be noted at the downstream pressure set point, allowing a smoother control in the pipeline.
The pilot system filter is high capacity (filtering area 50cm²) with stainless steel 316L body and transparent bowl. The dirt is trapped on the outside of the screen being collected in the bowl. The collected dirt can be flushed directly out to drain by opening the ball valve. This drain valve may be equipped with solenoid control and electronic programmable timer.
Standard valves are supplied with opening - closing speed control OCS. If required the valves can be equipped with OSCS allowing independent opening and closing speed control. These controllers are also made of SS 316L.
All the non-stainless steel accessories are nickel plated as standard, or SS 316.
There is a restriction orifice in the connection between the upstream section of pilot system and the control chamber, which will limit the flow rate that will cause the valve opening. Clearly, the valve will open, close or remain in the same position depending upon the decreasing or increasing of flow rate (pressure) in the control chamber. In order to make sure that the valve is able to close, the maximum flow rate allowed through the pilot is greater than the maximum flow rate allowed through the restriction orifice.
Taking A as the wetted area on the surface of the plug, the diaphragm area is approximately 3A. Therefore the diaphragm area that is exposed to P2 at outlet of main valve is equal to 2A.
The on/off or modulating pilot controls the main valve by controlling the pressure P3 in control chamber. Disregarding the mass of the diaphragm assembly, the forces that will cause the valve diaphragm assembly to move are:
The valve will open when the following condition is met.
P1.A + P2.2A > P3.3A + Fspring
In the same way, if the valve is open, it will move towards closing when.
P1.A + P2.2A < P3.3A + Fspring
If the sum of the forces applied on the top side of the diaphragm is equal to the sum of the forces on the bottom side the valve plug will remain stationary, allowing a modulation regime.
P1.A + P2.2A = P3.3A + Fspring
P3 is regulated by the variable pilot control between P1 and P2
No Flow - No Pressure
P1 = P2 = P3 + Pspring + Wda (Wda - Diaphragm assembly weight, only for horizontally installed valves).
Spring force will close the valve.