TECHNICAL INFORMATION METAL VAREA-METER STRAIGHT THROUGH TYPE ROTAMETER Electronic Transmitter INTRODUCING THE METAL TUBE VAREA-METER U.S. Filter/Wallace & Tiernan Products straight through metal tube Varea-Meters are available in a variety of tube sizes and flange faces and ratings. These are suitable for harsh process conditions and are designed for the measurement of high volume flows of aggressive fluids and gases. They have high pressure and temperature limits and give reliable flow measurements over a 10:1 range. As a standard feature, a rugged, magnetically coupled flow indicator is provided. An optional flow transmitter is available to provide local indication as well as a ma output. FEATURES Anti-Magnetic-Particle Float The extra long float magnet has a reduced flux density and is located above the metering disk. This discourages accumulation of magnetic particles, specially on the disk edge where they can cause errors in indication. Meter design directs the flow into a pattern, which scrubs the float and guides clean. The Varea-Meter is ideal for suspensions and slurries.
FEATURES No Float Extensions When the float is at rest, nothing projects beyond the flanges. Spool pieces are not required for installation and a frequent cause of damage when removing meters from a line is gone. In and out piping is vertical. Reliable Magnetic Coupling For reliable indication a powerful magnetic linkage exists between the float magnet and the indicator or transmitter magnets. Transmission and indication are reliable even under sudden flow surges. Easy Change-Out, Easy Coupling The indication unit and the transmitters are interchangeable. A mounting clamp attaches them to the meter tube. The same clamp attaches a flow switch 180 degrees from the indicator or transmitter. Clearance between any of these units and the tube leaves room for steam or electric tracing. Size for Size, Varea-Meters Give Greater Capacity, Cost Less Viscosity immune Varea-Meter floats have short lower bodies below the metering disc. This permits greater pressure recovery and restricts flow less than other designs. These floats permit tube-and-float combinations which yield higher capacities for a given tube size. A smaller size Varea-Meter can be specified for a given capacity at a cost saving. Easy Field Calibration Straight Through Varea-Meters can be bench calibrated. After mounting in process piping, a minor zero adjustment is made with a screwdriver. There is no need to break piping to get at the top of the meter when making this adjustment. Reliable Gas Measurement Down to 0 PSIG A unique dry snubber is standard on Varea-Meters used for gas service. It stabilizes the float, gives reliable indication down to atmospheric pressure for all meters 3/4 inch and larger. (Smaller meters operate down to 15 psig.) The dry snubber eliminates dashpots, preserves the straight through flow pattern. Offset piping is not necessary. GENERAL TECHNICAL DATA Accuracy 2% of full scale with standard calibration. Special calibration to 1% of full scale. Range 10 to 1. Dial Length 6 inches. 2 Dial Units Percent of maximum flow is standard. Gpm water, scfm air, or special graduations are optional. Flange Facings Raised face in ANSI 150, 300 and 600 lb. flat face in ANSI 150 and 300 lb. Standard rating for largefemale face, tongue-and-groove face, and ring-joint face is ANSI 600 lb. These ANSI 600 lb. flanges are also furnished to meet ANSI 300 lb. flange requirements since all mating dimensions, except flange thickness, are identical for both. Tongue-and-Grove Flanges Meters have groove (female) facings. Either small or large grooves are available. Tube and Float Materials Tube material 316 stainless steel. Float 316 stainless steel or Hastelloy C. Write for CG 500.001, which is a detailed listing of meter compatibility with a wide range of fluids. Flange Materials Raised face 150 lb. and 300 lb. in carbon steel, 316 stainless steel. All other facings available in 316 stainless steel only. (Extra low carbon stainless steel available on meters with 150 lb. flanges only.)
SELECTION PROCEDURE SELECTION PROCEDURE FOR LIQUID SERVICE Determine the capacity range, temperature and pressure capability, materials of construction, and options required for each meter. From chemical supplier determine float material. If the liquid is other than water, the desired units are other than GPM, its flow rate must be converted to GPM water (equivalent Flow Rate). How to Determine Water Equivalent For liquids with viscosities greater than the viscosity ceiling, Consult Distributor. For liquids with specific gravity other than 1.0 follow the Formula to determine Equivalent Flow Rate in GPM (QE). Equivalent = Desired X Correction Flow Rate Flow Rate Factors QE GPM = QD X FE X FU 1. From Table A determine FE from Specific Gravity Correction factors. 2. From Table B determine FU from Unit Conversation factors. 3. Work Formula to obtain Equivalent Flow Rate (QE). 4. Use Equivalent Flow Rate to select tube and float code from Table C on page 5. 3
SELECTION PROCEDURE SELECTION PROCEDURE FOR GAS SERVICE Determine the capacity range, temperature and pressure capability, materials of construction, and options required for each meter. From chemical supplier determine float material. Table C capacities, are air SCFM at 14.7 PSIA & 70ºF. If the gas is other than the above, its flow rate must be converted to SCFM air (Equivalent Flow Rate) How to Determine Air Equivalent 1. From Table A select appropriate Formula to determine Equivalent Flow Rate (QE). 2. From Table B determine FG from Specific Gravity Correction factors. 3. From Table D determine FP from Pressure Correction factors. 4. From Table E determine FT from Temperature Correction factors. 5. From Table F determine FU from Unit Conversion factors. 6. Work Formula to obtain Equivalent Flow Rate (QE) 7. Use Equivalent Flow Rate to select tube and float code from Table C on page 5. 4
ORDERING PROCEDURE METAL TUBE STRAIGHT-THROUGH VAREA-METERS 5
TECHNICAL DATA TEMPERATURE-PRESSURE RATINGS With 150 lb. ANSI flanges, all tube sizes: 230 psi at 0 F to 140 psi at 600 F With 300 lb. ANSI flanges, all tube sizes: 600 psi at 0 F to 360 psi at 600 F With 600 lb. ANSI flanges, 2-inch tube: 960 psi at 0 F to 620 psi at 600 F With 600 lb. ANSI flanges, 11/2 inch tube: 1200 psi at 0 F to 720 psi at 600 F With 600 lb. ANSI flanges, 1/2, 3/4, or 1 in. tube: 1200 psi at 0 F to 720 psi at 600 F ELECTRONIC TRANSMITTER FEATURES Factory Mutual Approved One transmitter model is Factory Mutual approved as intrinsically safe for hazardous locations. Another model, in a hazardous-service arrangement, is FM approved as explosion proof. Both models are dustignition proof. Reliable Magnetic Coupling A powerful magnetic coupling exists between the vertically moving float magnet and the rotation transmitter magnet. There is only one possible position of the transmitting mechanism for any float position. Transmission and indication are reliable, even under sudden flow surges. 600ºF Operating Temperature When used with an appropriate Varea-Meter flow tube, these U.S. Filter/Wallace & Tiernan Electronic Transmitters handle process fluids to 600 F with no loss of accuracy. Mounting on the meter tube leaves an air space to impede heat transfer; heat shields are not required. Careful selection of materials and non-lubricated bearing throughout improve hightemperature performance. Separate Flow Indication The scale and pointer readout is independent of the transmitting mechanism. The pointer indicates flow rate even if the transmitting element is removed or if power fails. Easy Addition in Field Any model can be ordered mounted on a new meter or can be easily added to an already-installed meter. Field installation does not require modification. removal, or even recalibration of the meter. A sliding internal bracket simplifies final zero adjustment. Design and Operation The transmitter is a low energy, high output load device. When used with an approved energy-limiting barrier, it is Factory Mutual approved as intrinsically safe in hazardous locations*. Position of the pointer and cam is achieved by a powerful magnetic linkage to the float. The cam has a captive follower which positions the mechanical arm of a differential capacitance bridge sensor. Any change in the bridge causes a proportional change in the transmitter s 4-20 ma output and in the bridge feedback voltage. The change in feedback voltage is used to rebalance the bridge. Zero and span adjustment are included. For stand-by operation, the transmitter is easily connected to operate from a battery system. A gasketed NEMA 4 enclosure protects the mechanism outdoors or in dusty or corrosive atmosphere. The transmitter is easily wired to an external stand-by battery. Choice of Arrangements The transmitter is available in a two-wire/four-wire general purpose housing which when used with an approved energy-limiting barrier, is Factory Mutual approved as intrinsically safe* for hazardous locations. It is also available in an explosion proof* and dust-ignition proof* arrangement. The transmitter gives reliable linear flowproportional milliampere signals, but other characterizations are available. The transmitter is interchangeable with any other readout and may be used with a flow switch. Local readout is on a 6-inch scale; standard calibration is percent of maximum flow. Calibration in custom units is optional. *As defined in Article 500, NEC. 6
TECHNICAL DATA Accuracy Combined meter and transmitter accuracy is 2% of full scale (1% with custom calibration). Sensitivity 0.2% of full scale. Linearity 0.4% of full scale. Repeatability 0.3% of full scale. Operating Range 10 to 1. Speed of Response Complete response to a flow-rate change from 10% to 90% of full scale in 0.5 seconds. Output Signals 4-20 ma dc flow proportional. Electrical Requirements Available from U.S. Filter/Wallace & Tiernan are: a 24 VDC supply for general purpose, intrinsically safe (with the appropriate electronic barriers), and explosion proof arrangements. Current Consumption: 5 ma signal current. Allowable Loop Resistance 0 ohms for 12 VDC supply, 500 ohms for a 22 VDC supply (maximum allowable for intrinsically safe operation); 600 ohms for a 24 VDC supply; 900 ohms for a 33 VDC supply. Output Load Effect Output independent of load. Temperature Range Maximum fluid temperature is 600 F; ambient range is 13 to 140 F. Temperature Effect Output changes less than 0.036% of full scale per degree F change from 13 F to 140 F. Electrical Classification General Purpose Enclosure: In NEMA 4 general purpose enclosure the transmitter is Factory Mutual approved as intrinsically safe for Class I, Division 1, Group A, B, C, and D hazardous locations when installed according to instruction book drawing 520.209.110.011. FM entity parameters: Vmax = 30V; Imax = 160 ma; Ci < 10 nf; Li = 50u H. Examples of electronic barriers acceptable under the entity system are: Pepperl & Fuchs transmitter converter KMD 2-cr-1.P.30300 or Zener barrier #Z728 or Z828; MTL #706 + 20 and FM approved as dust-ignition proof for Class II, Division 1 and 2, Group E and G and suitable for Class III, Division 1. Optional Explosion proof Arrangement: As an explosion proof arrangement, the transmitter is FM approved as explosion proof for Class I, Division 1, Group A, B, C, and D hazardous locations; and FM approved as dust-ignition proof for Class II, Division 1, Group E, F and G hazardous locations; suitable for Class III, Division 1. Connections Enclosed 1/2" conduit connection. Transmitter to receiver, unshielded wires. FLOW SWITCH Choice of Two External Alarms This compact option gives reliable high and /or low flow switching. The U.S. Filter/Wallace & Tiernan Flow Switch contains a powerful rotating magnet which responds linearly to float position. Its switches are long life, hermetically sealed reed types. Almost frictionless rotation of the switch magnet and its powerful bond with the float magnet give a dependable magnetic coupling. Even under sudden flow surges switching remains reliable. The switch is available in a UL listed, hazardous location* arrangement (Series 5500) and a general purpose arrangement (Series 5600) in NEMA 4 enclosure. Easily added in the field with the meter in the line. No extension rod, on interference with vertical piping. Can set switches to open or close on increasing or decreasing flow. In the general purpose model, this is done without removing the cover. A screwdriver adjustment sets each switch independently over 0 to 100% of the flow range. *As defined in Article 500, NEC. 7