The noise of control valves is a complex problem, because it simultaneously involves fluid mechanic phoenomena as well as often important technological and constructive problems. Some information about the causes of the noise generated by conventional control valves is summarised in fig. 1. LIMIPHON valves are designed and constructed to solve the acoustic problems valves are subject to when reducing the pressure of a gas (aerodynamic noise) and when controlling the flow rate of a cavitating liquid (Hydrodynamic noise). AERODYNAMIC NOISE LIMIPHON valves theoretically allow to meet any noise level requirement.Practicaly the lowest noise level really obtainable is the one directly produced by the flow inside the piping. HYDRODYNAMIC NOISE For service with liquids under cavitating conditions, LIMIPHON valves solve the problem totally since they are sized to prevent the cavitation.Therefore the acoustic disturbance produced by the liquid flow is the only remaining one, but this is normally negligible, if the velocity has been suitably chosen
materials:
Forged or welded in the same material as the body. construction:
Plain or finned, flanged or pressure sealed. packing:
Teflon - graphite, pure graphite, teflon V-rings.
Plug
constructions:
It consists of a solid or shaped cylinder.
It's available either as balanced or unbalanced design. materials:
17-4-PH, F6NM, AISI 316 + Stellite, CrMo + Stellite. Throttling throtting characteristic:
It's determined by the distribution of the ports discovered by the plug during its stroke.
Normally it's linear but on request can be supplied also as modified linear. inserts:
In the tight and balanced construction there is a sealing ring inside the sliding chamber of the plug (cage or guide). Such a ring is made of teflon or pure graphite according to the working temperatures.
DISK STACK
construction:
It consists of a number of drilled disks packed by bolts or welded, locked in the body by the bonnet itself (with sliding sealings) or by an internal ring. For special constructions the internal of the cage is protected by a drilled cage made of hardened material. materials:
AISI 304, AISI 316, Special Chromium steel, Monel, 17-4-PH.
Seat
construction:
It consists of a ring clamped between body and disks stack and bearing the seating surface for the plug. leakage classes:
- IV or V class IEC 534-4 for metal-to-metal seating.
- Higher classes with teflon insert.
- For seat diameter up to 4'' is available aspecial insert which allows tight sealing with
max Δp = 250 bar and max T = 200°C
Actuators
Diaphragms, series 1-X-210, can be fitted up to a maximum stroke of 100 mm. Single or double action pneumatic cylinders, series 1-X-400 are available. The positioners are used in conjunction with the cylinders for a better control. Oleodynamic cylinders are available as on option together with control accessories and an electric drive motor.
Contact
us
_z91_9000_e - PDF ( 451.53 KB )
