Worksheet S-1
by M. Fraganza and M. Miccio based on the Examination test of June 11,2014
rev. 1.1 of 30.04.2019


Objectives

  • Selection and sizing of a regulation valve starting from the data provided by the manufacturer in the form of a table.
  • Calculation and plotting of its Intrinsic Characteristic.
  • Calculation and plotting of its Flow Characteristic.
  • Plotting of the Installed Characteristic
  • Calculation of a working point chosen by the user

Go to data input

Data given by the manufacturer:

Data given by the manufacturer BELIMO for modulating ball valve :

DN

(inches)↓

→ %rotation of the sphere

] Cv

Data input for valve sizing:


go to installed characteristic

Select the liquid type

from the drop-down list:

atm
Pa
psi
bar

upstream pressure P1


downstream pressure P2

vapor pressure Pv
kg/s
lb/min

mass flow rate

nominal valve diameter (inch)

Valve selection through the comparison of the Cv to 70% opening :

►►►

►►►

►►►

◄══►

Calculation of the intrinsic characteristic and its graphic representation:


NB: the intrinsic characteristic is similar to the classic "equipercentage"

Calculation and plotting of the Flow Curve :

OTHER DATA:

da "Annex D"

vedi Magnani, Ferretti e Rocco

►►►

►►►

►►►

Writing the salient vectors, we give an asymptotic representation of the Flow Curve:

Data for the installed characteristic
atm
Pa
psi
bar

pressure drop on the valve Pn (nominal) :

Authority V:

►►►

Characteristic graphs:

►►►

Estimate of the RANGEABILITY:

The RANGEABILITY, as a first approximation, is estimated as the ratio between e

for the nominal diameter chosen

Transit flow rate and pressure drop calculation for a predetermined percentage rotation value:

percent rotation at which the flow rate is to be calculated (%):

Calculations made for the relative stroke value that is closest to the chosen value:


which corresponds to a rotation angle in degrees [°]:

►►►

►►►

►►►

Calculate the transit flow rate  for an opening angle  = 27 °