figure 1805 series flow data - nibco.com

AHEAD OF THE FLOW®

Figure 1805 SeriesFlow Data

½” - 2”

Circuit Balancing Valve

PT 600CWP

Engineering Data ®

Circuit Balancing Valve - Venturi

1NIBCO INC. WORLD HEADQUARTERS • 1516 MIDDLEBURY ST. • ELKHART, IN 46516-4740 • USA • PH: 1.800.234.0227

TECH SERVICES PH: 1.888.446.4226 • FAX: 1.800.234.0557 • INTERNATIONAL OFFICE PH: +1.574.295.3221 • FAX: +1.574.295.3445www.nibco.com

Static circuit balancing valves (CBV) are either fixed orifice or variable orifice designThe variable orifice CBV is a well known competitive product but advances in design and manufacturing technology have allowed the fixed orifice CBV to become a mainstream balancing valve.It is known that the fixed orifice balancing valve traditionally has a plate type orifice sometimes as a separate but close coupled product or integral with the valve body. This style of CBV has an accuracy of ± 5%.The increasing use of low flows in water distribution circuits means that the signal measured across an orifice is quite small and often difficult to measure.The NIBCO® Fig 1805 fixed orifice circuit balancing valve has progressed even further and incorporates a venturi orifice within the body providing a high signal accuracy.Liquid passing through the venturi orifice undergoes a reduction in pressure as the velocity increases and reaches its minimum value in the vena contracta area of the orifice.

At the outlet of the orifice the pressure increases as the velocity of the liquid reduces but the pressure does not recover to its upstream value. The pressure recovery of liquid flowing through a venturi is higher than through an orifice, which reduces the absolute pressure loss which in turn improves energy efficiency.The pressure is measured at the upstream and downstream PT ports.Accurate laboratory tests have established the signal flow coefficient Cvs. This is a constant value for each size of fixed orifice circuit balancing valve.Reference to the single line flow graphs in this manual will allow the flow rate to be established when the signal Δps is known.

+–

∆Psig

nal

∆Pve

nuri

∆Pva

lve

Permanent pressure loss

∆Psignal and ∆Pvalve are measured values allowingCvs and Cv to be calculated

Engineering Data®

Figure T-1805-LF, S-1810-LF Series Cvs Values

NIBCO INC. WORLD HEADQUARTERS • 1516 MIDDLEBURY ST. • ELKHART, IN 46516-4740 • USA • PH: 1.800.234.0227TECH SERVICES PH: 1.888.446.4226 • FAX: 1.800.234.0557 • INTERNATIONAL OFFICE PH: +1.574.295.3221 • FAX: +1.574.295.3445

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Body ½”, B1 ½”, B1 ¾”, B1 ¾”, B1 ¾”, B2 ¾”, B2

Venturi Code V1 V2 V1 V2 V3 V4

Cvs 0.667 2.087 0.665 2.039 2.484 5.729

Flow Coefficient Cv & CvsCv relates to the FOCBV pressure loss whilst Cvs relates to the signal across the venturi for flow measurement. Cvs = Q √ΔP/27.68 where Q = gpm ΔP = differential pressure in inches H2O

Cvs Values - Flow Measurement

Note: Suffix LF indicates lead-free*. Valve diagram on the graph shows the T-1805 Flow data applies to lead-free* valves. Minimum Open Position • A circuit balancing valve should not be used below 25% open (Position 1) except for the purposes of isolation. Maximum Open Position • Valves can be operated throught 90˚ to the full open position but when regulated and the memory stop is set the allowable rotation will be less than 90˚.

* Weighted average lead content ≤ 0.25%

2

Body 1”, B2 1”, B2 1”, B3 1¼”, B4 1½”, B5 2”, B6


Cvs 2.446 4.656 5.685 10.86 15.25 25.24

Engineering Data ®

Circuit Balancing Valve - Venturi

1NIBCO INC. WORLD HEADQUARTERS • 1516 MIDDLEBURY ST. • ELKHART, IN 46516-4740 • USA • PH: 1.800.234.0227

TECH SERVICES PH: 1.888.446.4226 • FAX: 1.800.234.0557 • INTERNATIONAL OFFICE PH: +1.574.295.3221 • FAX: +1.574.295.3445www.nibco.com

3

Nominal Body Size

BodyMarking

Fixed EndSize

Union EndSize

VenturiCode

CvsValue

½” B1 ½” ½” V1 0.667

½”” B1 ½” ½” V2 2.087

¾” B1 ¾” ¾” V1 0.665

¾” B1 ¾” ¾” V2 2.039

¾” B2 ¾” ¾” V3 2.484

¾” B2 ¾” ¾” V4 5.729

1” B2 1” 1” V3 2.446

1” B2 1” 1” V4 4.656

1” B3 1” 1” V5 5.656

1¼” B4 1¼” 1¼” V6 10.86

1½” B5 1½” 1½” V7 15.25

2” B6 2” 2” V8 25.24

Body and Venturi CombinationsThe valve can be supplied in a combination of body and venturi combinations.For the ½”, ¾” and 1” sizes the body size may change as well as the fixed and union end sizes.The body size is identified by the letter ‘B’ followed by a number included in the body markings e.g. B1, B2.The venturi is identified by a ‘V’ code followed by a number e.g. V1, V2.The fixed and union ends can be supplied in a combination of female and male threads, solder and press connections.

Engineering Data®


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Graph of Head Loss against Flow Rate attributable to the valve installed in a circuit Velocity based on the average inside diameter of Schedule 40 pipe

½” Fig. T-1805-LF, S-1805-LF Series Circuit Balancing

4

Body Code - B1: Venturi Code - V1: Cvs = 0.667

Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s

NOTE: ± 3% Accuracy range is from 1 to 2 gpm. Accuracy may exceed 3% below 1 gpm.

PT 600CWP

Engineering Data ®


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Graph of Signal against Flow Rate Velocity based on the average inside diameter of Schedule 40 pipe

½” Fig. T-1805-LF, S-1805-LF Series Circuit Balancing

5



Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s

PT 600CWP

Engineering Data®


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¾” Fig. T-1805-LF, S-1805-LF Series Circuit Balancing


NOTE: ± 3% Accuracy range is from 0.8 to 2 gpm. Accuracy may exceed 3% below 0.8 gpm.Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s

6

PT 600CWP

Engineering Data ®


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Graph of Signal against Flow Rate Velocity based on the average inside diameter of Schedule 40 pipeBody Code - B1: Venturi Code - V2: Cvs = 2.039


Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s

NOTE: ± 3% Accuracy range is from 2 to 7 gpm. Accuracy may exceed 3% below 2.0 gpm.

7

PT 600CWP

Engineering Data®


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8


Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s

NOTE: ± 3% Accuracy range is from 1.8 to 8 gpm. Accuracy may exceed 3% below 1.8 gpm.

PT 600CWP

Engineering Data ®


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9


Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s


PT 600CWP

Engineering Data®


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10


1” Fig. T-1805-LF, S-1805-LF Series Circuit Balancing Valve


Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s

PT 600CWP

Engineering Data ®


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11




Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s

PT 600CWP

Engineering Data ®


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12


Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s

NOTE: ± 3% Accuracy range is from 2.0 to 18 gpm. Accuracy may exceed 3% below 2 gpm.

PT 600CWP

Engineering Data ®


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1¼” Fig. T-1805-LF, S-1805-LF Series Circuit Balancing

13



Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s

PT 600CWP

Engineering Data®


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1½” Fig. T-1805-LF, S-1805-LF Series Circuit Balancing

14


NOTE: ± 3% Accuracy range is from 6.0 to 50 gpm. Accuracy may exceed 3% below 6 gpm.

Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s

PT 600CWP

Engineering Data ®


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15




Flow - gpm

Sign

al -

inch

es H

2O

Velocity - ft/s

PT 600CWP

Engineering Data®


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Recommended Flowrates

NOTE: Please reference the individual charts in this Flow Data Brochure for specific information regarding flow and accuracy characteristics.

Body ½”, B1 ½”, B1 ¾”, B1 ¾”, B1 ¾”, B2 ¾”, B2


Cv 0.740 2.876 0.716 2.867 4.514 10.331

Body 1”, B2 1”, B2 1”, B3 1¼”, B4 1½”, B5 2”, B6


Cv 4.540 7.092 9.951 17.905 23.705 38.855

Cv Values - Pressure Loss with Valve Fully Open

Nominal Body Size

BodyCode

VenturiNumber

Minimum Flowrate - gpm

Maximum Flowrate - gpm

½” B1 V1 0.24 2.0

½”” B1 V2 0.80 6.0

¾” B1 V1 0.24 2.0

¾” B1 V2 0.8 6.0

¾” B2 V3 1.0 8.0

¾” B2 V4 2.3 18.0

1” B2 V3 1.0 8.0

1” B2 V4 2.3 18.0

1” B3 V5 2.2 18.0

1¼” B4 V6 4.3 35.0

1½” B5 V7 4.8 50.0

2” B6 V8 6.0 80.0

12/18

figure 1805 series flow data - nibco.com

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