Product Handbook 2026 - Volume 1

Flowmetering Gilflo and ILVA flowmeters 3

Step 2. Using the value of Q E as determined in Step 1, select the correct size of the ILVA flowmeter using the Table below. In practice, it will often be the line size that determines the choice of the flowmeter.

Flowmeter type

Max. Q E litres/min

Max. pressure drop Wg

DN250 DN300

7 750

200

00

10 975

200

P S T F P F T S x P S T F 00 P F T S x x

Example: Determine which ILVA pipeline unit is required to measure the flow of compressed air when: 1: Estimated maximum rate of flow = 28 000 s m³/h at 7 bar g and 20 °C. Note : Standard conditions = 1.013 bar a, 0°C giving a standard density of 1.29 kg/m³

D S

P S

T F

Q

E = Q S

2: Calculate Q E from:

F F D P P x 1000 P T x T F x

1 000 P F T S x x S E S Q = Q D S P S Q = Q

Q

E = Q S

S S x 1000 P T F F D P P S S

1 000 P F T S x x S E S

3.2 17

1.29 1.013 293 x 1000 8.013 273

Q =(28000 x 16.667) x

x 1.29 1.013 293 x 1000 8.013 273 x

E

Q =(28000 x 16.667) x

E

Q E = 6 174 litres/min

So a DN250 ILVA is recommended. Note: 1 m³/h = 16.667 litres /min

How to order example 1 off Spirax Sarco DN250 ILVA flowmeter suitable for fitting between EN 1092 PN16 connections.

D S T F 000 P F T S x x S T F 000 P F T S x x S P S E = Q S E = Q S E S E S = Q S E = Q Q D S D S Q D S P S S F S S S

P S P S

T F T F

D P P 1 000 P F T S x x S 1 000 P F T S x x S x Q = Q D P P E S E S F F x Q = Q S F

F F x 1000 P T D P P D P P x 1000 P T S S F F S S x x S

F F x 1000 P T S S S S x 1000 P T S F

F

1.29 1.013 293 x 1000 8.013 273 1.29 1.013 293 x 1000 8.013 273 x x x

1.29 1.013 293 x 1000 8.013 273 1.29 1.013 293 x x 1000 8.013 273

16.667) x =(28000 x 16.667) x 16.667) x =(28000 x 16.667) x Q =(28000 x 16.667) x E E

TI-P337-46 EMM Issue 6

Page 5 of 7

ILVA Flowmeter DN250 and DN300

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