![]() The critical flow orifice prover is used to test gas turbine meters at operating pressures of 15 psig or more. The critical flow prover test method has the advantage of the meter being tested under the same conditions andconfiguration that it normally operates. Critical flowprovers are of two types-the critical flow orifice prover and the critical flow venturi prover. If friction is indicated by unsuitable spin down time, the bearings shouldbe replaced.ĬRITICAL FLOW PROVERS-ORIFICE/VENTURIA critical flow prover is a constriction type flow meter in which the phenomenon of critical flow occurs as the gas velocityin the throat of the meter is accelerated to equal the velocity of sound in the pipe at operating conditions. These spin down times and their respective calibration curves represent an example of a typical 4" gas turbine meterand indicate the loss due to friction in bearings. PULSES/ACTUAL CUBIC FEETAir Calibration ofDaniel Gas Turbine MeterSerial No.: 74-G-100Model No.: 2000-0Size: 4"Ĭurve No.: 74-111Customer: Natural Gas Co. Conduct the spin test in a relatively draft-free environment or by blocking off back ofinner housing. Be sure to record the spintime of this test for future reference. A spin test is conducted and recorded on the gas turbine meterspecification sheet by Daniel prior to shipment, but another test is advised before installation. The turbine meter output is rated in pulses per unit volume.ĭaniel offers two independent, isolated pick ups which can be used with the Daniel local totalizer and/or flowinstrumentation capable of accepting inputs of pressure, temperature, and density transducers for calculationsof corrected flow or mass.įour Ways of Meter ProvingSPIN TESTA spin test of the gas turbine meter rotor does not represent absolute proof over the entire range of the meter, but onlyan indication of its accuracy in the lower range. As the magnet passes the coil it produces a voltagepulse which represents a discrete unit of volume. ![]() ![]() The Daniel Gas Turbine Meter is furnished with two magnetic pick ups which sense the rotation of the rotorthrough accurately positioned magnets in the rotor hub. Hence, by accurately measuring the rotor rotation, the volumetric flow can be determined. The angular velocity of the rotor is directly proportional to the gas velocityand consequently to the volumetric flow rate. The gas impinges on the rotorblades causing the rotor to rotate. The rotor is designed with aspecific number of blades positioned at a precise angle to the flow stream. The increase in velocity provides ample rotor drivingforce.Īfter the flowing gas has been accelerated, it flows through the meter rotor. The flow deflector or nose cone is used to increase thevelocity of the gas to prepare its entry to the meter rotor. Range is the ratio of maximum flow to minimum flow over which the specified accuracy will be maintained.Īccurate Measurement ExplainedAs the gas flow enters the meter inlet, it is guided through a flow area created by the inside diameter of themeter and the outside diameter of the flow deflector. Repeatability is a meter's ability to indicate the same reading each time the same flow conditions exist.Turbine meters exhibit excellent repeatability and, for many control applications, this parameter is moreimportant than accuracy or resolution. Electro-magnetic turbine meters have an inherently high resolution. Highresolution is generally required only on meters handling the sale of products which must be periodically proved,or on meters for control purposes. Resolution is a measure of the smallest increment of total flow that can be individually recognized. Accuracy at aparticular flow rate may be an order of magnitude better than "rated flow range accuracy." It is generallyexpressed as a percent of true volume for a specific flow range. Turbine Meter ParametersAccuracy is a measure of how close to true or actual flow the instrument indication may be. Incombination with Daniel's totalizing and computing equipment, the gas turbine meter becomes the heart of gasmeasurement systems for virtually any situation.Ĭontinuous display flow rate and totalization It has fewer moving parts because of its patented electronic design. From entire packaged meter stations to specific components, the Daniel expertise is there.ĭaniel's Gas Turbine Meter is an example of this expertise and leadership position in flow measurement. The Flow Products Division hasas its goal the development and manufacture of the most accurate and reliable flow measurement equipment inthe industry. is a recognized leader in the field of flow measurement. ![]() Product/System OverviewGAS TURBINE METERS4" THROUGH 12"CATALOG 2000įorewordDaniel Industries, Inc. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |