Most municipal water systems were built through many years, following the natural growth of the cities. Some parts are decades old (sometimes even centuries old).

As the pipes of the system get old- water leakage through joints, rust spots, cracks, faulty accessories etc. became numerous and difficult to detect.

The result is large loss of potable water, which, in some cases, reaches considerable percentage of the valuable treated water.

The solution to this problem may be:

a. Replacing the old network by a new one- this solution requires heavy investments and serious obstacles to normal life due to the unavoidable excavations.
b. Renewing the pipes by inner lining- can be done in certain cases.
c. Reducing the system pressure to the required minimal level, lowering losses to the minimum.

How does the low pressure prevent excessive losses?

Recent years research has proven that with most common system, there is a linear relation between the pressure change in a pipe system and the volume of water loss from the same system. i.e. – a reduction of 20% in the line pressure would create a similar reduction in the losses!

Can we reduce municipal network pressure?

Normally, the pressures created in the network are calculated so the far from the pump and/or high areas, which are the hydraulically- inferior ones, will get the minimally- needed pressure to provide the requested water flow at all times.

As a result, the nearer and lower areas get higher pressure- exceeding the value required for satisfactory water supply.

Reduction of pressure in these areas will:

a. Save water by restriction of leakage (as described above).
b. Increase uniformity of water distribution.
c. Reduce the frequency of new bursts and leaks creation.

Can we optimize the performance of standard PRVs?

Obviously it is not possible to limit the main arteries pressure, as it will reduce the remote areas pressure below the minimum. But all branches, which get higher levels of pressure, may be pressure-controlled, limiting their pressure to the minimal value.

The branch itself is designed to provide its supply area with certain flow rate, and the inlet pressure should be such that will guarantee the right conditions at the end of the branch.

Through low demand time (at night) the flow is minimal and so is the branch friction loss.

Lower pressure value at this period will not effect the pressure at the branch end but will increase water saving.

This can be done by using a range of pressure reducing applications that will modulate the PRV set pressure following flow changes or time of the day.

Dorot PRVs

DOROT valve manufacturers supply pressure reducing valves to be installed at the branches junctions.

These valves, sized 40mm to 700mm (11/2”-28”), are controlled by spring- loaded, diaphragm operated, adjustable pilot valves allowing accurate downstream pressure control regardless of upstream pressure and flow rate fluctuation.

The extreme simplicity results in easy installation, pressure adjustment and in-line maintenance procedures, which can be carried by unskilled personnel using regular tools.

The pressure rating of the standard valve ranges from 0.2 bar (3 psi) to 16 bar (230 psi) so they can be used in any normal network (25 bar model is available as well).

The unique structure of DOROT valve allows accurate regulation at extremely wide flow rate range, as expected in municipal systems.

When high main pressure is reduced to low branch pressure, cavitation conditions may develop. DOROT valves have an exceptionally low cavitation index, making it resistant to most normal working conditions. In addition, DOROT supplies Cast Bronze valve for severe cavitation conditions.

Electric control version enables selection of two (or more) pressure set points, by electric timer, for different day / night setting.

Electronic controller, added to the basic valve, enables different pressure values in the day and the week. This ultra-sophisticated control allows also automatic adjustment of the pressure as required by varying flow.

A unique Hydraulic Pressure vs. Flow modulating valve (the HyMod) allows simple operation with no need for power source or computer connection.

Very competitive prices justify this water waste prevention mean in a short operation period.

DOROT provides an experienced technical assistance to potential users and designers through its local distributors and the factory-engineering department.

Please consult with DOROT Technical service for technical information.

For other information please contact our local distributor near you or our international marketing department