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GENERAL SPECIFICATION
SV METERS
GS. No. GBS100-3-E
(Critical nozzles)
s GENERAL
Critical nozzles are devices that can be used for
flowmetering, making use of the behaviour of gas flow in
the sonic velocity region (critical flow) and are
characterized by a high degree of accuracy and
repeatability. Because of their excellent repeatability,
critical nozzles are accepted as national standards in many
countries for gas flow measurement. Called SV meters, we
supply them in a variety of sizes for your specific needs.
s FEATURES
1. Fabricated by our proprietary design and precision
machining technology, products are individually calibrated
for flow characteristics to ensure the specific rate of flow
desired at a high degree of accuracy.
2. The flowrate is determined by the factors of physical
properties of the fluid, which depend on the temperature,
pressure, etc. upstream of the meter, SV meter's inside
diameter and coefficients of flow characteristics. It does
not require measurement of differential pressure and is
insensitive to pressure fluctuation downstream of the
meter.
3. Total absence of moving mechanical parts and parts
subject to deterioration from wear means long life and
desirable repeatability.
4. Materials used are treated to ensure long-term stability, to
protect against corrosion and aging.
s Our scheme to establish and maintain
meter accuracy
Aiming at fully complying with the most demanding
standards for traceability and flowmetering technology,
comparative testing against internationally established
standards for flow measurement is maintained in our
calibration program.
International Comparison Testing
s GENERAL SPECIFICATIONS
Item
Flow rate Standards
in Individual States
(NIST for example)
National Flow
rate Standards
Comparison Testing
Description
Metered fluid
Expansion uncertainty
Better than ± 0.34% (K=2)
Sound velocity range
0.5 max.(downstream press./upstream press.)
Material
Master Flowmeters
(OVAL Corporation)
Air
Stainless steel (SUS304)
Sealing
Calibration
Double O-rings (JIS B 2401)
SV Meters Under Test
Temperature 10 ~ 35°C
50kPa (abs.) min.
0 ~ 70%
s FLOW RANGE AND OUTLINE DIMENSIONS
Any single flow rate point between
0.0271 and 55.6
SV Meter O.D.(ø)
39.7e8
SV Meter Length(L)
30
Collar Height (A)
85
1
S
2
Model
3 4
5
V
K
11
Mounting opening (øD)
39.7H9
s OUTLINE DIMENSIONS
0 0
0 1
0 2
0 3
0 4
0 5
0 6
0 7
0 8
0 9
1 0
1 1
Unit of Measure
L
Nozzle Dia.
Description
6
Flowrate-related code
Flow Range
L/s
Dims., mm
s MODEL CODE NUMBER
Application
Operating
Pressure
Range
Humidity
0
9
SV Meter
For general-purpose flowmeter
For master flowmeter
Standard Flowrate L/s
0.02713 max.
0.05425
0.1085
0.2170
0.4340
0.8681
1.736
3.472
6.944
13.89
27.78
55.56
Reads in L/s
Standard
Other than above
OVAL Corporation
Head Office: Tokyo; Tel. 81-3-3360-5121. Fax 81-3-3365-8605
Beijing Office: Tel., Fax. 86-10-6525-3601. Tel. 86-10-6513-3516
Overseas Branch Offices: Seoul. Singapore. Taipei
http://www.oval.co.jp
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