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GENERAL SPECIFICATION (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 Metered fluid Expansion uncertainty Sound velocity range 0.5 max.(downstream press./upstream press.) Master Flowmeters (OVAL Corporation) SV Meters Under Test s FLOW RANGE AND OUTLINE DIMENSIONS Any single flow rate point between 0.0271 and 55.6 Flowrate-related code Flow Range L/s Dims., mm s MODEL CODE NUMBER Operating Pressure Range Humidity 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

s Typical Applications of SV Meters Because the SV meter produces a stable mass flow (volume flow) by maintaining gas pressure and temperature at constant level upstream of the meter, it is beneficial for gas flowmeter calibration and for producing a continuous flow at a fixed rate. Shown below are its typical applications. 1. Calibration standard for other types of flowmeters 3. Pass/fail screening for gas control equipment, etc. Connected in series with other type of flowmeter, calibration of the meter under test is achieved by reference to the flowrate of SV meter. Allowing the SV Meter...