HyMod
Description:
Dorot model HyMod is an automatic pilot controlled, pressure reducingvalve activated by the pressure of the pipeline.The valve reduces upstream pressure to a downstream pressure thatincreases or decreases simultaneously with the demand flow.The pressure into the zone is continually adjusted according to the zone'sactual demand, thus compensating for the system loss.The pressure-flow profile can be adjusted. The Dorot HyMod will control from no flow, to maximal full open flowwithout any chattering or slamming.
Features:
Maximum potential water saving by redaction in leakage
Reducing burst frequency
No power supply requirements
Utilizes a standard pilot valve with no bias chambers or design changes
No extra moving parts in addition to those of a standard fixed outlet PRV
Fast, real time response to demand changes
Simple to commission, operate and maintain
Completely stable down to no-flow demand.No throttling plug or by-pass valve used
The pressure-flow profile can be easily modulated in situ for optimization,without need for orifice plate replacement
Typical installation:
Models:
HyMod Type 1 - Is fitted with a stainless steel sluice valve, enabling maximalflexibility for the user to alter the pressure-flow modulation and minimumcompromise between allowed losses and required modulation range.
HyMod Type 2 - Is fitted with a stainless steel orifice plate, enabling the userto alter the pressure-flow modulation for in situ fine tuning in a specific range,without the need for orifice plate replacement.
Pressure-Flow Profiles
The pressure will change at a user selectedprofile determined by two points:
Required valve low outlet pressure PL atminimal demand flow QL (normally - nightdemand at 03:00 AM).
Required valve high outlet pressure PH atmaximal demand flow QH.
Design Notes
The PRV creates a defined minimumpressure differential (head loss). To this,one should add (PH-PL)/4 loss created bythe modulation device. This loss shouldbe incorporated in the design considerations.This note refers to cases where the upstreampressure may drop to near the maximalpressure setting - PH.
Regulating valves may operate in destructive cavitation conditions.Refer to Dorot's relevant publications for further information.
Minimal pressure setting (PL) should be equal or larger than therequired minimal pressure (PCN) plus the elevation difference (?H)between the critical node in the system and the HyMod location.PL ? PCN + ?H
Maximal pressure setting (PH) should be equal or larger than therequired minimal pressure (PCN) plus the elevation difference betweenthe critical node in the system and the HyMod location plus maximalexpected system losses (?h) at maximal demand flow.PH ? PCN + ?H + ?h
Optional Features
Electric and or Manual On-Off control
Hydraulic check-valve function
Limiting maximal pressure
Excessive Flow Shut-Off function.
Where to use
The HyMod application is designed for the use inPressure Management schemes where the targetpressure in the zone (normally the AZP) changes asa result of varying demand. These changes are oftenassociated with high leakage index and burst frequency.
Where not to use
Where constant logging option is required - considerusing electronically modulated PRV model PRM (EF).
Where two point pressure reducing (time or flowmodulated) is more cost effective - consider usingPRM (E2), PRM (D2) or PRM (FR) models.
Where there are no significant losses between thevalve location and the AZP - consider using fixed outletPRV model PR.
