GENERAL CHARACTERISTICS The network has gained increasing importance trying to conciliate available water reserves and the always increasing request for water. Usually, the network capacity is always greater than the effective request; this implies the necessity to utilize devices able to control the distribution of the water without wasting it. Needle valve is especially designed to realize the function of regulating the water flow, maintaining an easy handling even in circumstances which comport heavy hydrostatic loads at its mouth and a very different exercise pressure. The use of needle valve...

VALVE SECTION connect the correct dimensioned valve to the main pipeline . In case of installation long a pipeline together with a main shout off valve it is reccomanded to keep a ences and turbolences . Larger diameters are also available on request in electrowelded steel.

TECHNICAL REPORT ON HYDRAULIC BEHAVIOUR NEEDLE VALVE DIMENSIONING Report made on the bases of the “Di Nicola” valve testing, realized by “Istituto di Idraulica Agraria Università di Napoli” (1991 ). The needle valve dimensioning is not based on the conduit diameter but on the pressure conditions in Required data Aim: The following report is to illustrate the technical reasons by which the valve is not subject to cavitation phenomena when used in a correct way. Maximum upstream pressure (Hm stat- meters of water column) Maximum downstream pressure (Hv max - m.w.c.) Piezometric pressure in the...

CAVITATION CAUSES AND EFFECTS CAVITATION DIAGRAM “SIGMA” When the pressure drops below the vapour saturation in the water, gases are generated with subsequent release of vapourbubbles in the zone of depression. In this pressure difference downstream, implode reverting back to liquid form and damagin the inner walls of the piping. The shocks due to the high pressure localized on the walls of the valves and the pipes cause great damages. to them added to the heavy noise and destructive vibrations. The nearby conduit creating, in its interior, a collapse area for the vapour bubbles that prevents...

NEEDLE VALVES WITH ACCESSORIES OPERATING UNITS AND ACCESSORIES This type of valve can be supplied as a solution to several flow control problems. The followings are the most frequently encountered a. Down pressure control Needle valve, with down stream positioned pressure gauge controlled by computer, is a very good solution to keep the pressure constant into the down stream pipe line even in presence of big changes of pressure range into the upper stream adductor pipe line. 4.Local3control electric diagram 2 panel 5.Remote control and signaling 6 6.Relief valve PRINCIPLE SKETCH- PLAN N° 2 Electric...