6-9-p0027-0080-vx21_en.pdf - 第47页

VX21 /22/23 Series Flow Rate Characteristics 1 Note) Use this graph as a guide. In the case of obtaining an accurate flow rate, refer to pages 66 through to 70. How to read the graph The sonic range pressure to generate …

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VX21/22/23 Series
Example 1)
Obtain the pressure difference when water [15 L/min] runs through the solenoid valve with a Kv = 1.5 m
3
/h.
As the flow rate when Kv = 1 is calculated as the formula: Q0 = 15 x 1/1.5 = 10 [L/min], read off ∆P when Q0 is
10 [L/min] in Graph (2). The reading is 0.036 [MPa].
Example 2)
Obtain the saturated steam flow rate when P1 = 0.8 [MPa] and ∆P = 0.008 [MPa] with a solenoid valve
with a Kv = 0.05 [m
3
/h]. Read off Q0 when P1 is 0.8 and ∆P is 0.008 in Graph (2), the reading is 20 kg/h.
Therefore, the flow rate is calculated as the formula: Q = 0.05/1 x 20 = 1 [kg/h].
Conversion of flow coefficient:
Kv = 0.865
Cv ···········································································(11)
Here,
Cv factor: Value of the clean water flow rate represented by US gal/min that runs through the valve at 40 to
100°F, when the pressure difference is 1 lbf/in
2
(psi)
Value is different from
Kv and Cv factors for pneumatic purpose due to different test method.
(4) Test method
Connect the equipment for the test to the test circuit shown in Fig. (3), and run water at 5 to 40°C. Then, measure the flow rate with
a pressure difference where vaporization does not occur in a turbulent flow (pressure difference of 0.035 MPa to 0.075 MPa when
the inlet pressure is within 0.15 MPa to 0.6 MPa). However, as the turbulent flow is definitely caused, the pressure difference needs
to be set with a large enough difference so that the Reynolds number does not fall below 1 x 105, and the inlet pressure needs to
be set slightly higher to prevent vaporization of the liquid. Substitute the measurement results in formula (8) to calculate Kv.
Fig. (3) Test circuit based on IEC60534-2-3, JIS B 2005-2-3
Test range
Equipment
for test
Thermometer
Throttle valve
in the
upstream side
Throttle valve in the
downstream side
Flow
meter
Pressure
tap
2
d
≥ 20d ≥ 7d
6d
Pressure
tap
Water flow rate Q0 [L/min] (When Kv = 1)
Saturated steam flow rate
Q0
[kg/h] (when
Kv
= 1)
Pressure differential
∆P [MPa]
Upstream pressure
P1 = 1 MPa
P1 = 0.8 MPa
P1 = 0.6 MPa
P1 = 0.5 MPa
P1 = 0.1 MPa
P1 = 0.2 MPa
P1 = 0.4 MPa
Example 2
Example 1
P1 = 0.3 MPa
1
10
100
1
10
100
0.001 0.01 0.1
20
3
4
30
20
5
30
0.002 0.003 0.02 0.03 0.040.004
2
3
4
5
2
50
4040
50
Graph (2) Flow rate characteristics
70
VX21/22/23 Series
Flow Rate Characteristics 1
Note) Use this graph as a guide. In the case of obtaining an accurate flow rate, refer to pages 66 through to 70.
How to read the graph
The sonic range pressure to generate a flow rate of 400 L/min (ANR) is P
1
≈ 0.2 MPa for a ø4 orifice and P
1
≈ 0.58 MPa for a ø3 orifice.
How to read the graph
When a water flow of 2 L/min is generated, ∆P ≈ 0.013 MPa for a valve with ø3 orifice.
For Air
Downstream pressure of valve (P2) [MPa]
1.0
0.8
0.6
0.4
0.2
0
ø2
ø3
ø4
ø5
ø7
ø8
ø10 (Connection: 1/4)
ø10 (Connection: 3/8, 1/2)
Flow rate
Q
[L/min (ANR)]
50 100 150 200 250 300 400350
100 200 300 400 500
1,000
400 600
600
800 1,000 1,200
200 1,400
350 700
400 700 1,000 1,300
500 700
700
1,000
Upstream pressure of valve
P
1 ≈ 1.0 MPa
Subsonic
Sonic
Critical
pressure
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
For Water
Flow rate
Q
[L/min]
30
20
10
5
4
3
2
1
0.1
0.001 (0.0018) (0.0054) 0.01
(0.013)
0.05 (0.07)
Pressure differential ∆P = (P1 − P2) [MPa]
ø4
,
ø5
ø8
ø7
ø3
ø2
ø10
71
VX2
VXK
VXD
VXZ
VXS
VXB
VXE
VXP
VXR
VXH
VXF
VX3
VXA
VX2
VX21/22/23 Series
Flow Rate Characteristics 2
Note) Use this graph as a guide. In the case of obtaining an accurate flow rate, refer to pages 66 through to 70.
For Saturated Steam
How to read the graph
The sonic range pressure to generate a flow rate of 15 kg/h is P1 ≈ 0.55 MPa for a ø2 orifice and P1 ≈ 0.28 MPa for a ø3 orifice.
1.0
0.8
0.6
0.4
0.2
0
0.1
(664)(183)
(663)(179)
(662)(174)
(661)(170)
(660)(164)
(658)(158)
(656)(151)
(654)(143)
(650)(133)
(646)(120)
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
5 10 15 25
20
10 15 20 25 45
403530
40
2010 30
30
40 50 60
50 60 70 80
20 30
20
40 60
30 45
35 50
Downstream pressure of valve (P2) [MPa]
Flow rate
Q
[kg/h]
Upstream pressure of valve
P
1
≈ 1.0 MPa
Subsonic
Sonic
ø2
ø3
ø4
ø5
ø7
ø8
ø10 (Connection: 1/4)
ø10 (Connection: 3/8, 1/2)
Critical
pressure
72