Flowmetering

Vortex flowmeters

Analog

Standard input 2 x 4 - 20 mA active or passive.

Standardoutput 1x4-20mA(Optionaloutputof3x4-20mA)

Scaled pulse output

Output can be scaled so that 1 pulse indicates a specific quantity of fluid passing through the pipe,

up to 10 pulses/sec.

Relay output

2 x SPDT, 24 V / 50 mA. Output can be scaled so that 1 pulse indicates a specific quantity of fluid passing

through the pipe, up to 10 pulses/sec.

Communications

Modbus RTU - Half duplex RS-485

Modbus TCP / IP - Full duplex, 10 / 100 Base T Ethernet

HTTP web server, 10 / 100 Base T Ethernet

BACnet MS / TP compatible. Standard and FM Certified models only.

Remote electronics Up to 30 m (100 ft) of RS-485 cable

3.7.5

Nominal

size

Nominal

pulse rate

hz/m/sec

(ht.ft / sec)

Nominal

flowmeter factor

pulses / litre

pulses / m3

(pulses / gal)

(pulses / ft3)

DN25

(1")

3.66

(12.00)

1 216

(321.2)

680

(2 403)

DN40

(11⁄2")

2.29

(7.50)

309

(81.7)

173

(611)

DN50

(2")

1.83

(6.00)

148

(39.1)

83

(293)

DN80

(3")

1.22

(4.00)

44.3

(11.7)

25.0

(87.2)

DN100

(4")

0.91

(3.00)

18.9

(5.0)

10.6

(37.6)

DN150

(6")

0.61

(2.00)

5.7

(1.5)

3.1

(11.0)

DN200

(8")

0.40

(1.30)

2.3

(0.6)

1.2

(4.2)

DN250

(10")

0.37

(1.20)

1.1

(0.3)

0.6

(2.2)

DN300

(12")

0.30

(1.00)

0.76

(0.2)

0.4

(1.3)

Nominal

size

Flow range in

L/S

Min.

Max.

Flow range in

U.S GPM

Min.

Max.

DN25

(1")

0.2 4.5 3.4 72.0

DN40

(11⁄2")

0.5 11.1 8.3 176.0

DN50

(2")

0.9 18.6 13.8 295.0

DN80

(3")

1.9 41.6 30.9 659.0

DN100

(4")

3.4 72.3 53.8 1 147.0

DN150

(6")

7.7 163.9 121.9 2 600.0

DN200

(8")

13.5 287.2 213.5 4 555.0

DN250

(10")

22.6 482.5 358.7 7 653.0

DN300

(12")

32.0 683.7 508.3 10 843.0

Flowmeter sizing

Selecting the appropriate size flowmeter can be critical. If the flowmeter is over-sized, the signal strength could be weak – limiting

rangeability. If the flowmeter is under-sized, excessive pressure drop or cavitation may occur – affecting accuracy. Use the minimum

linear flow velocity curves and Tables 1 through 5 (minimum and maximum flowrates for various types of applications) for general sizing.

For more detailed information, contact your Spirax Sarco representative.

Table 1 Nominal pulse rate and flowmeter factor

Table 2 Water flowrates

Notes:

1. Water values are determined at standard conditions of 16°C

(60°F)

2. The minimum flowrate for the DN25 (1") and DN40 (11⁄2")

flowmeters are below the linear range

(Reynolds number < 20 000).

3. The velocities used to calculate the minimum and maximum

flowrates were 0.46 m / sec (1.5 ft / sec) and 9.75 m / sec

(32 ft/sec), respectively.

Output and Input

For flowmeter sizing go to

www.spiraxsarco.com and type sizing program in the search engine

TI-P338-26 MI Issue 4

VLM10 In-line Vortex Mass Flowmeter

Page 4 of 11