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Solenoid and Process Valve Engineering Data. 
We have compiled a list of liquid flow and air flow formulae to allow users to calculate solenoid valve flow and pressure drop which are the key factors when choosing any solenoid, angle seat or process valve. This helps make sure systems will have sufficient flow, the correct valve size so avoiding additional costs or valve failure.
A complete media viscosity cross reference guide as liquid media thickness can be measured in various formats so in this way engineers will avoid installing a solenoid or process valve that would not be compatible with the media being controlled.
The compete IP Ingress Protection Chart, pressure, volume, flow, temperature and length cross reference guides to help. 
 
Liquid Flow Formulae
Air Flow Formulae
Q=Kv x Square Root of (DP/d) or DP=d(Q/Kv)2
Where DP less than P1/2
Where DP equal to P1/2
Q=1.69Kv x Sq Rt (DPxP2)
Q = 0.84Kv x P1
Q = Flow L/Min
DP = Pressure Drop (Bar)
d = density i.e. Water = 1
Kv = flow factor coefficient of valve (L/Min)
(N.B. DP 5 - 10% is preferred)
Q = Flow (M3 Hr)
DP = Pressure Drop (Bar)
Kv = flow factor coefficient of valve (M3 Hr)
P1 = inlet pressure + 1 bar
P = absolute downstream pressure =(inlet pressure + 1 bar - DP)
Saybolt Universal (seconds)
Engler (degrees)
Kinematic (centistokes)
Saybolt Universal (seconds)
Engler (degrees)
Kinematic (centistokes)
-
1.05*
1.5
103
3.0
21.3
34
1.15*
2.5
109
3.2
22.8
37
1.25*
3.4
115
3.4
24.1
40
1.3*
4.2
125
3.7
26.7
42
1.4*
5.0
137
4.0
29.2
45
1.45*
5.7
148
4.3
31.7
50
1.6*
7.5
160
4.6
34.2
57
1.8*
9.4
171
4.9
36.8
62
1.9
11.0
183
5.2
39
68
2.1
12.6
205
5.9
44
74
2.2
14.2
242
7
50
79
2.4
15.5
256
7.3
55
85
2.6
17.0
285
8.1
62
92
2.7
18.6
313
8.9
68
98
2.9
20.0
342
9.8
74
PRESSURE
 1 Bar = 14.5 PSI
1 Bar = 100 kPa (Kilopascal)
1 PSI = 6.9 kPa
1 Kg/cm = 0.98 Bar
1 Atmosphere = 1.013 Bar
1 Inch Water gauge = 2.49 mbar
1 mm Mercury = 1.33 mbar
1 Ton / in = 154 Bar
 
 Volume
 1 Gallon (UK) = 4.54 Litres
1 Gallon (USA) = 3.79 Litres
1 Pint (UK) = 0.57 Litres
1 Pint (USA) = 0.47 Litres
1 Fluid Once (UK) = 28.4 cm
1 Fluid Once (USA) = 29.6 cm
 
FLOW
1 CFM = 0.472 Litres a second
1 CFM = 0.000472 m/Sec
1 CFM = 28.32 Litres a minute
 
 Temperature
 From F to C
Add 40 then multiply by 5
then divide by 9 then -40
 From C to F
Multiply by 9 then 40
divide by 5 then +40
 
  Length
 
1 Inch = 25.4mm
1/16 Inch = 1.5875mm
1 foot = 0.305 Meters
1 Mile = 1.609 Kilometre
Degrees Of Protection Provided By Electrical Enclosures (IP rating
1st No
Definition
Test Type
2nd No
Definition
Test Type
 1
 Protected against objects
50mm
 Connexion IP10 Rating
 1
Protected against 
vertically falling water drops 
 Connexion IP01 Rating
 2
 Protected against objects
12.5mm
 Connexion IP20 Rating
 2
 Protected against 
vertically falling water
drops up to 15 degrees inclination 
 Connexion IP02 Rating
 3
 Protected against objects
2.5mm
 Connexion IP30 Rating
 3
 Protected against vertically falling
water drops up to 60
degrees inclination
 Connexion IP03 Rating
 4
 Protected against objects
1mm
 Connexion IP40 Rating
 4
 Protected against splashed water
in any direction
 Connexion IP04 Rating
 5
 Dust Protected
 Connexion IP50 Rating
 5
 Protected against water jets
from any direction
 Connexion IP05 Rating
 6
 Dust Tight
 Connexion IP60 Rating
 6
 Protected against powerful
water jets from
any direction
 Connexion IP06 Rating
 
 
 
 7
 Protected against temporary
water immersion
 Connexion IP07 Rating
 
 
 
8
Protected against the
effects
of submersion
Connexion IP08 Rating

Definitions and conversion factors for the three valve flow coefficients Kv, Cv and Qn.

 

1. What is the Kv Value?

2. What is the Cv Value?

3. What is the Qn Value?

4. Converting between Kv, Cv & Qn

 

1. What is the Kv Value?

Kv value is the metric measure for the flow of a valve. It is defined as:

The volume flow in cubic metres per hour of water at a temperature of between 5 and 40 Celsius with a pressure drop across the valve of 1 bar.


2. What is the Cv Value?

Cv is the imperial measure for the flow of a valve. It is defined as:

The volume flow in US gallons per minute of water at a temperature of 60 Fahrenheit with a pressure drop across the valve of 1 psi.


3. What is the Qn Value?

Qn value is used in pneumatics to define the flow of a valve. It is defined as:

The volume flow in litres per minute of air at a temperature of 20 Celsius, with an input pressure of 6 bar and a pressure drop across the valve of 1 bar.


4. Converting between Kv, Cv & Qn

Kv = 0.86 x Cv
Kv = Qn / 1078

Cv = Kv / 0.86
Cv = Qn x 0.0008

Qn = Kv x 1078
Qn = Cv / 0.0008

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