Hoffer Engineering Guide for Liquids

Product catalog summary

Principle of Operation: Hoffer inline turbine flowmeters utilize a vaned rotor to measure fluid velocity. The rotor's rotation generates an electrical frequency signal proportional to the flow rate, converted using the meter's K-factor.

Performance Characteristics: These flowmeters provide linear output with +/-0.5% accuracy over a 10:1 turndown range for liquids with viscosities between 0.8 to 2 centistokes. Repeatability is within +/-0.1%, varying with coil and bearing types.

Sizing: Guidelines for meter size selection are based on flow ranges and viscosities. For higher viscosities, linear flow ranges are recommended, and signal linearization may be necessary for extended ranges.

Installation: Proper installation requires symmetrical velocity profiles with straight pipe runs (10 diameters upstream, 5 downstream). Strainers are recommended to prevent debris, and meters should be installed in positive pressure lines to avoid cavitation.

Materials of Construction: Material selection is based on chemical compatibility, with standard materials including 316/316L stainless steel for bodies and internals, and options for custom materials.

Bearing Selection: Bearings are chosen based on chemical compatibility, lubricity, temperature, and flow conditions, with options including hybrid ceramic, hard carbon composite, and tungsten carbide bearings.

End Connections and Pressure Ratings: Common connections include NPT and MS flared types, with pressure ratings detailed in tables. Custom designs are available for higher pressures.

Coil Selection: Two main coil types are used: magnetic and RF. Magnetic coils impose a drag on the rotor, affecting flow range, while RF coils do not. Selection depends on factors like temperature, viscosity, and signal requirements.

Specifications and Coil Selection: The document outlines pulse types available with the Redi-Pulse option and provides guidelines for coil selection for specific applications, including temperature range and signal transmission distance.

Bi-Directional Flow and Pulse Security: Hoffer inline turbine meters can be used for bi-directional flow applications, equipped with two sensing coils for direction determination and pulse security, crucial for custody transfer and legal-for-trade applications.

Viscosity Effects: The document discusses measuring viscous fluids, recommending ball bearings and calibration on a viscosity similar to the operating viscosity, with UVC correction for non-linear outputs due to viscosity changes.

Density Effects: Liquid density is generally not a concern, except for low-density hydrocarbon products. Compensation for temperature/density effects may be necessary in applications with significant density changes.

Calibration Options: Most flowmeters are wet-calibrated and traceable to NIST, with standard and additional calibration options available for different viscosities.

Hazardous Area Applications: Hoffer provides turbine flowmeters and accessories to meet hazardous area rating specifications, including explosion-proof and intrinsically safe equipment.

Corporate History: Hoffer Flow Controls has over 30 years of experience in designing and manufacturing turbine flowmeters, with a strong reputation in cryogenic flow measurement and custom designs.

Ordering Information: The document lists basic information required for evaluating applications and sizing the appropriate turbine flowmeter, including fluid description, flow rates, viscosity, and temperature range.

Catalog excerpts

Hoffer Engineering Guide for Liquids Accurate, Versatile, Economical...

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Illustration 1 ● Turbine Flowmeter Cutaway Hoffer inline turbine flowmeters are velocity measuring devices, which is Pickup Coil to say they measure the average velocity of a fluid flowing through Riser the body of the meter. See Illustration 1 for details on the Flow construction of the Hoffer inline Straightener Flowmeter turbine flowmeter. Mounted within Housing the body of a Hoffer liquid turbine flowmeter is a vaned rotor. The rotor is centered on a shaft and allowed to rotate by means of bearings. The shaft is supported in Deflector Cones the housing by tube bundles that also provide a...

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MCP not recommended in 4” and larger sizes NOTE: Performance enhancement techniques are routinely applied to produce larger linear and usable flow ranges. Consult with the applications group at Hoffer with your requirements. for-trade, a flow straightening tube bundle in the upstream section is normally required to eliminate any rotation of the flow stream about its axis of flow. Hoffer offers a complete line of installation kits and flanged flow straightening sections that provide the required straight runs of piping in and out of the flowmeters as an option and meet API and AGA design criteria...

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Figure 3 ● Pressure Drop Characteristics for HO Series on Liquid Service P(e) = equilibrium vapor pressure of the liquid at the operating temperature in PSIA Pressure Drop: See Figure 3 for pressure drop across the meters and the side-bar note for calculating pressure drop at viscosities other than 1 cstk. Materials of Construction: The materials of construction selection for a turbine meter usually are based upon chemical compatibility between the flowing liquid and wetted components of the meter. In the case of Hoffer turbine flowmeters, the wetted components include the meter body and the...

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Table 4 ● Bearing Selection Hybrid Ceramic Ball Bearing Hard Carbon Composite Sleeve Tungsten Carbide Sleeve Use in “3A” Sanitary Series? Use in Dirty/Abrasive Service? Temperature Range: Requires Lubricating Liquid? General Corrosion Resistance: Extended Flow Range Service? Fair-Lubricity Dependent Fair-Lubricity Dependent Note: Temperature range of meter will also be limited by coil temperature range. See Table 8 on page 6. Bearing Selection: A specific bearing type is selected first on chemical compatibility with the flowing liquid. Other considerations include lubricity of the liquid, operating...

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Table 7 ● Flanged Series Maximum Allowable Working Pressure Ratings Meter Size Flange Size Maximum ANSI Class Flange (See Note 2) Max. Allowable Working Pressure (See Note 2) Note 1: Flange size must match meter size. Note 2: Maximum allowable flange class & pressure rating are specific to the flange material selected. Consult factory for details. The most popular threaded type end connections for Hoffer inline turbine flowmeters are the male NPT type and the male 37° flared MS type. Hoffer can readily supply other thread forms including BSP, JIS, SAE and metric to name a few. The most popular...

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Figure 4 ● Viscosity Effects on 1" Flow- Viscosity Recommendation Nominal Meter Size 1/4" - 12" Max. Recommended Viscosity 300 Cstks. * * Subject to operating pressure and pressure drop across the meter. use of a flow computer with a quadrature discriminator circuit it is then possible to determine direction of flow. A dual coil arrangement may also be specified for applications requiring pulse security; a technique common to certain custody transfer and legal-for-trade flow measurement applications. A third coil may also be added for use as a spare coil or for ease of connection to a flow meter...

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Corporate History Hoffer Flow Controls brings over 30 years of experience designing and manufacturing quality turbine flowmeters and related process measurement and control instrumentation. Our initial experience was in the field of cryogenic flow measurement. Today our reputation in this field is synonymous with quality. Tens of thousands of Hoffer turbine flowmeters are on the job today throughout the world in applications ranging from oil well fracturing to food processing. Providing turbine flowmeters of varying configurations is our specialty. Our broad line of state-of the art electronics...

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