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Products  >  Control Applications Solutions  >  HyMod - Pressure Reducing Valve with Hydraulic Flow Modulation  >    

HyMod - Pressure Reducing Valve with Hydraulic Flow Modulation


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.


  • 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:


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:

  1. Required valve low outlet pressure PL atminimal demand flow QL (normally - nightdemand at 03:00 AM).
  2. 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 (ΔH)between the critical node in the system and the HyMod location.PL ≥ PCN + ΔH
  • 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 (Δh) at maximal demand flow.PH ≥ PCN + ΔH + Δh

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.

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