DS1810

Page 4 of 4

TRIM SIZING FORMULAE

The tabulation gives the Cv and Kv values for each Trim size, as calculated according to the formulae below:

NOTE:

Liquid formula applies only to clean, bubble free liquid with no cavitation or flashing and with Reynolds Number 100,000 minimum.

US UNITS

Cv

=

Q

Q=

Flow US GPM

G=

Specific Gravity (H20=1)

∆P=

Pressure Drop, psi

Cv

=

Q

60

Q

=

Flow, SCFH

G=

Specific Gravity (Air=1)

T=

Temperature, ºK

P=

Inlet Pressure psia

∆P=

Pressure Drop psi

G

∆P

293 P ∆P

GT

SI UNITS

Kv

=

Q

Q=

Flow m

3

/h

G=

Relative Density (H20=1)

∆P=

Pressure Drop bar

Kv

=

Q

29

Q

=

Flow Nm

3

/h

G=

Relative Density (Air=1)

T=

Temperature ºK

P=

Inlet Pressure, bar abs

∆P=

Pressure Drop, bar

G

∆P

293 P ∆P

GT

LIQUIDS

GASES

Cv MAX

3.0

2.0

1.25

0.8

0.5

0.32

0.2

0.13

0.08

0.05

0.03

0.02

0.01

0.006

0.003

0.002

0.0013

0.001

0.0006

0.0004

0.00027

0.00018

0.00012

0.00008

Kv MAX

2.6

1.7

1.1

0.7

0.43

0.27

0.17

0.11

0.07

0.04

0.026

0.017

0.0086

0.0052

0.0026

0.0017

0.0011

0.00086

0.00052

0.00034

0.00023

0.00015

0.0001

0.00007

TRIM

A

B

C

D

E

F

G

H

I

J

K

L

M

N

P0

P1

P2

P3

P4

P5

P6

P7

P8

P9

Valve Size

A

B

C

1/4”

54 50 15

1/2”

70 73 25

DIMENSIONS

C

B

Topworks Air-to-Close

A

150mm Ø

Topworks Air-to-Open

150mm Ø

2 Downgate Drive, Sheffield, S4 8BT, England

Tel: +44(0)114 244 2521

Fax: +44(0)114 243 4838

email: sales@roxspur.com

www.roxspur.com

Every effort has been made during the preparation of this document to ensure the accuracy of statements and specifications. However, we do not accept liability for damage, injury, loss or

expense caused by errors or omissions made. We reserve the right to withdraw or amend products or documentation without notice.

Head Office: 2 Downgate Drive, Sheffield, S4 8BT, England

Tel: +44(0)114 244 2521

Fax: +44(0)114 243 4838