G SERIES - GLOB TYPE HYDRAULIC CONTROL VALVE

PRODUCT DESCRIPTION

The globe type hydraulic control valves are used for pressure, flow and level control at water distribution lines, fire protection systems, irrigation networks and filtration applicatons. The globe control valves are designed as diaphragm controlled, clack shut-off valves. The valve’s body’s globe type design has easy installation and maintenance advantages.

PROPERTIES

The main valve consists of 3 basic parts which are globe type valve body, diaphragm assembly and cover.
Because of the only moving part of the valve is diaphragm assembly, the maintenance of the valve is quite easy and cheap.
With the usage of pilot valves that provide different control types mounted on the main valve, in practice the desired modulation function can be done easily.
The diaphragm assembly works rigidly through the valve shaft beared to the main valve’s two points (upper and lower). Thus, the valve does the opening-closing up and the modulation function more efficiently.
The main valve shaft’s bearings don’t have any shaft bushing. By this means, the valve can work long years with no need to any maintenance.
An indicator shaft can be mounted on the main valve. The valve’s working position can be observed by this means.
The valve’s impermeability clack gasket can be changed.
The valve can do modulation function even at very low flows through “Radial Port” that is mounted on the impermeability clack.
The valve’s diaphragm is a synthetic rubber that is strengthened with cord fabric. Different diaphragms can be used for desired applications.
The corrosion resistant spring helps the impermeability clack to close fully up by providing extra power to the diaphragm assembly.
The diaphragm does modulation function precisely with the help of the actuator.
The valve doesn’t create pressure fluctuations in the network by closing slowly and impermeable up.
The main valve body can be easily transformed to a double control reservoir at desired necessary applications.

OPERATION PRINCIPLE

The globe type hydraulic control valves work with the line pressure totally hydraulic in the network. The valve doesn’t need any extra energy source like electrical, pneumatical, mechanical etc. when carrying out the opening-closing up and the modulation function. The basic logic at working principle is the area difference between the diaphragm and the impermeability clack. The pilot valves mounted on the main valve are the equipments that provide the main valve work at opening-closing up and modulational positions. Different pilot valves are used for different applications.

VALVE OPEN
Normally the main valve is at the closed up position. In this position, the evacuation port of the pilot valve mounted on the main valve is opened up. Thus, the pressured water in the main valve’s actuator is relieved by the help of the pilot valve. Because of no pressure in the actuator, the line pressure pushes to the clack that creates a power in the direction of the opened up position. That created power maintains the main valve be at the opened up position.The valve’s minimum open up pressure is about 0,7 bar (10 psi).

VALVE CLOSED
In this position, the pilot valve mounted on the main valve closes the evacuation port. The line pressure is transfered to the valve’s actuator. The pressure in the actuator is very close to the line pressure at the valve’s Closed Up Position. The pressure in the actuator creates a power to the diaphragm assembly in the direction of the closed up position. The valve’s diaphragm area is larger than the clack’s area. Because of this area difference the valve’s close up power will be much bigger than the open up power. Thus, the main valve will be impermeable at the closed up position.

MODULATION POSITION
The pilot valve mounted on the main valve at desired applications, provides the main valve to work at Modulation Position. The desired modulation function can be adjusted by the pilot valve. The pilot valve adjusted at a desired value makes stable the difference pressure in the actuator or flowrate between the adjusted values. It provides the main valve work at the modulation position by reflecting this difference pressure to the main valve’s actuator. At the pressure reduction, pressure stabilization and flow control functions the main valve works at this position.

TECHNICAL PROPERTIES

VALVE SELECTION TABLE

Q : Flow - m³/h
ΔH : Difference Pressure - bar,psi
Kv : Flow Coefficient (Metric) - m³/h
Cv : Flow Coefficient (U.S)
V : Water Speed- m/s
K : Valve Resistance Coefficient - Dimensionless

MATERIAL LIST

HEADLOSS CHART

CAVITION TABLE

Cavition
Generally, at the Pressure Reducing Control Valve applications, because of the cross sectional narrowings on the valve, the pressure conditions change too. The most narrow point is the point that the speed is at maximum and the pressure is at minimum. From this narrow point, the most kinetic energy transforms to turbulance, separations, to heat and at some sections to pressure. If the pressure drops under the fluid’s vaporization pressure, the cavitation that causes mechanical damage to the valve, starts. Being careful to not to cross the cavitation boundary is essential in these kinds of applications.

SIZE AND WEIGHT TABLE