CALEFFI 142251A Manuale - Pagina 6

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Operating Principle

Use of the balancing

valve: setting the

flow rate (fig F-G)

The 142 series balancing valve is a

hydraulic device that controls the flow

rate of a fluid. Turning the knob moves a

plug within the fluid stream which varies

the flow rate. The flow rate is determined

according to the pressure drop value

measured by a differential pressure meter

connected to the pressure test ports.

The opening position is indicated by the

numbered indicator (fig. E):

- The turn indicator (1) shows a

regulating scale scale from 0 to 4

(0 closure, 4 complete opening).

Turning the knob manually through

360° causes the indicator to move by

one unit.

NOTE: the indications + and – on the

drawings refer to the pressure upstream

and downstream of the component

whose pressure differential is to be

measured.

For the connection of the pressure test ports

of the valve (2) with a differential pressure

measuring device (3), use a pair of fittings

with a measuring probe (fig. F).

a) As the thermal fluid passes,

measure the Δp of the valve with

any suitable differential pressure

measuring device(fig. G);

b) Using

the

characteristics"

sheet

code 18203 supplied in the

pack), find the flow rate value

that is passing through the valve,

consulting the diagram "Δp-flow

rates" corresponding to the size

of the valve used.

c) Turn the knob and repeat steps a)

and b) until you reach the desired

value.

Correction for liquids of different densities

If using liquids with a density different from water at 70°F (20°C)

≈ 62.4 lb/ft

( ≈ 1 kg/dm

using the following formula:

Δp

= Δp

water

"Hydraulic

(sheet

), correct the value of the measured head loss Δp

where:

Δp

= reference head loss in (psid(kPa))

Δp = measured head loss in (psid(kPa))

= fluid density in lb/ft

(kg/dm

)