Needle Valve

Needle valve is a high pressure valve which consists of a body, cylinder, piston, flow regulators, shaft and gears. It cannot be used in sewage media, but can be used for
any purpose as long as it is clean water media. However, main area of usage is the conditions where butterfly valve or gate valve cannot be used.
Needle valves are used where,
Accurate flow control is required.
Differential pressure is 16 bars or greater.
Highly pressurized water is released to open atmosphere like dams.
Cavitation is a problem.
Throttling is required.

Pressure Class : PN10 / PN16 / PN25 / PN40
Inlet and Outlet Body Material : Ductile / SS316
Cylinder Material : Ductile / SS316
Bolts & Nuts Material
: SS316
Gasket Material
: EPDM / NBR
Piston Material
: Ductile / SS316 / Aluminum Bronze
Coating
: WRAS approved fusion bonded epoxy. 300 microns dft as standard.

As a parameter of geometric design, there is a water-drop shaped chamber in the middle of needle valve. As flow travels around that chamber, section of flow turns into a ring. As it continues, flow is forced to be directed at centre at outlet side of valve. Cavitation occurs and finishes inside the flow and does not create any damage on valve or other equipment. Operation of Needle Valve, By means of a mechanism, piston moves forwards and backwards inside the cylinder. When piston moves into the cylinder, flow begins through the space between body and cylinder. Valve is open at that position.
As piston approaches to body, section area of flow is reduced, velocity is increased. When piston contacts with body, valve closes and flow stops.

There are flow regulators (flow guides) at the section between body and cylinder. These guides which can be vaned, helical vaned, slotted or perforated type are selected according to flow conditions. Since piston is under balanced pressure, changes at pressure do not change torque requirement at operation shaft. High torque values are not required. Valve opens and closes easily and smoothly.
Movement of piston under operation is linear. It gives the ability of accurate and easy flow regulation.
Needle valves have an indicator for open-close positions. It helps to see opening degree of valve.
Installation Position: Valve can be installed as shaft in vertical or horizontal position. It can be installed in any position.
Accessories: Operation System, Opening-closing mechanism of valve is inside it. It does not require additional gearbox. If manual operation is preferred, hand-wheel or cap-top can be mounted on spindle. For electrical operation, actuator can be mounted directly without using any other accessory.
Maintenance: There is no need for maintenance for these valves. If valve is uninstalled, it is recommended to check disc ring (rubber ring), o- rings and change if necessary.