SITRANS F US clamp-on ultrasonic flowmeters provide highly accurate measurement while minimizing installation time and maintenance expense.

Особенности

• Easy installation; no need to cut pipe or stop flow
• Minimal maintenance; external transducers do not require periodic cleaning
• No moving parts to foul or wear
• No pressure drop or energy loss
• Wide turn-down ratio
• Choice of single, dual or multiple channel versions and a variety of enclosures - to suit your operating conditions and requirements

Область применения

SITRANS F US clamp-on ultrasonic flowmeters have six product families, each targeting specific applications:

FUS1010 and FUP1010 General purpose flowmeters are suitable for a wide variety of liquid applications, including the following:

• Water industry
  Raw water
  Potable water
  Sludges
  Chemicals
• Wastewater industry
  Raw sewage
  Effluent
  Sludges
  Mixed liquor
  Chemicals
• HVAC industry
  Chillers
  Condensers
  Hot & cold water systems
• Power industry
  Nuclear
  Fossil
  Hydroelectric
• Processing industry
  Process control
  Batching
  Rate indication
  Volumetric and mass measurement

FUE1010 Energy flowmeters are ideally suited to thermal energy / power industry applications, including:

• Chilled water sub-metering
• Hot water sub-metering
• Condenser water
• Glycol
• Thermal storage
• Lake source cooling

FUH1010 Oil flowmeters are ideal for applications carrying crude oil, refined petroleum or liquefied gas. There are three application areas: Interface detectors, volumetric flowmeters and mass or standard volume flowmeters

Interface detectors / density meters

• Precise identification of interfaces on multi-liquid pipelines
• Rapid and precise scraper "pig" indication
• Product identification
• Density indication

Viscosity compensated volumetric flowmeters

• Applications with multiple liquids having a wide viscosity range
• Automatic gross volume compensation due to viscosity changes

Standard volume (net) mass flowmeters

• Standard (net) volume flow measurement
• Suitable for use in leak detection systems
• Mass flow output measurement
• Interface detection
• Scraper (“pig”) detection
• Chemical and petrochemical processing

FUG1010 Gas flowmeters are ideal for most natural and process gas industry applications, including:

• Checkmetering
• Allocation
• Flow survey verification
• Lost and unaccounted for (LAUF) analysis
• Production
• Storage

FUS1020 General purpose flowmeters are suitable for most clean liquid applications, including the following:

• Water & wastewater industry
  Potable water
  Wastewater, influent & effluent
  Processed sewage, sludge
• Chemical feed industry
  Sodium hypochlorite
  Sodium hydroxide
• HVAC & power industries
  Coolant flow
  Fuel flow
• Process control
  Chemicals
  Pharmaceuticals

System information and selection guide

Transducer type selection guide

Функции

Operating Principle

The SITRANS FUS1010 system is a transit-time ultrasonic meter that provides exceptional performance using a non-invasive clamp-on approach. Ultrasonic transducers transmit and receive acoustic signals directly though the existing pipe wall, where the fluid refraction angle is governed by Snell’s law of refraction.

Clamp-on transducer mounted in a reflect configuration

The beam refraction angle is calculated as follows:

sin Ө = c / V_φ

c = Velocity of sound in fluid

VФ = Phase velocity (a constant in the pipe wall)

The flowmeter automatically compensates for any change in fluid sound velocity (or beam angle) in response to variations in the average transit-time between transducers A and B. By subtracting the computed fixed times (within the transducers and pipe wall) from the measured average transit-time, the meter can then infer the required transit-time in the fluid (T_Fluid).

The Sound waves traveling in the same direction as flow (T_A,B) arrive earlier than sound waves traveling against the direction of flow (T_B,A). This time difference (Δt) is used to compute the line integrated flow velocity (v) as shown in the equation below:

v = V_Ф / 2 · Δt / T_Fluid

Once the raw flow velocity is determined, the fluid Reynolds number (Re) must be determined to properly correct for fully developed flow profile. This requires the entry of the fluid’s kinematic viscosity (visc) as shown in the equations below, where Q represents the final flow profile compensated volumetric flow rate.

Re = Di · v_Ф / visc Q = K(Re) · ( π / 4 ·Di² ) · v_Ф

v = Flow velocity

visc = μ / ρ = (dynamic viscosity / density)

K(Re) = Reynold flow profile compensation

In all wetted type ultrasonic flowmeters the meter constants are configured prior to leaving the factory. As this is not possible with clamp-on meters, the settings must be made by the customer at the time of installation. These settings include pipe diameter, wall thickness, liquid viscosity, etc.

SITRANS Clamp-On meters that include temperature sensing can be configured to dynamically infer changes in fluid viscosity for the purpose of computing the most accurate flow profile compensation (K_Re).

Ultrasonic Transducer Types

Two basic types of Clamp-On transducers can be selected for use with the SITRANS FUS1010 flowmeter. The lower cost “universal” transducer is the most common type in the industry and is suitable for most single liquid application where the sound velocity does not vary much. This transducer type can be used on any sonically conductive pipe material (including steel) making it well suited for portable survey applications. Universal transducers are selected based on the pipe diameter range alone, so wall thickness is not important to the selection process.

The second transducer type is the patented WideBeam transducer (called high precision), which utilizes the pipe wall as a kind of loudspeaker to optimize the signal to noise ratio and provide a wider area of vibration. This makes this kind of transducer less sensitive to any change in the fluid medium.

The WideBeam transducer is designed for steel pipes, but can also be used with aluminum, titanium and plastic pipe. It is the preferred transducer for HPI and gas applications. Note that unlike the universal type, this transducer selection is dependent only on the pipe’s wall thickness.

Automatic Zero Drift Correction (ZeroMatic Path™)

When WideBeam transducers are installed in the “Reflect” mode configuration shown below, the acoustic signal travels in two different paths between transducers A and B. One path “ACB” travels through the pipe wall and fluid, while the other path “AB” never enters the fluid medium.

This later path provides the meter with a reference signal that is completely independent of flow rate and can therefore be used as a measure of transducer “mis-match”. By continually analyzing this pipe wall signal the FUS 1010 meter can dynamically correct for flow errors caused by zero drift.

Multi-Channel Flowmeters

For improved flow profile averaging, redundancy, or better cost per measurement, Clamp-On meters can be supplied with 1 or 2 measurement channel, with 4 channel meters supplied as special order.

In the standard FUS, FUP, FUE systems, these channels can be installed on separate independent lines or in a multi-beam installation as shown below. This choice is made during meter setup, where either a multi-beam (two beams on same pipe) or multi-channel installation can be selected.

Dual Beam installation example

Doppler (Reflexor^®) Operation

The Doppler measurement technique relies on the reflection of sound energy off tiny gas bubbles or suspended particles to create a doppler shift in the fixed frequency acoustic transmit signal, as shown below.

When de-demodulated using FFT signal processing, this doppler shifted frequency (Δf) can be used to measure the flow rate as described in the associated doppler equations below.

Although the standard transit-time measurement system is very tolerant of high levels of liquid aeration and high solids content, there will be cases where insufficient signal will be available for operation with transit-time mode. For these cases the FUS, FUP and FUE meters can be ordered with this optional doppler capability, which requires an additional doppler transducer.

SITRANS meter family description

SITRANS FUS1010 flowmeters

The FUS1010 system is a basic function permanent (or dedicated) clamp-on meter that is available with a full range of safety approvals, I/Os and enclosure types. This meter can be used in a wide range of applications but does not include the special functions found in the hydrocarbon FUH and energy FUE flowmeters.

The FUS1010 meter is typically programmed with a fixed viscosity and specific gravity entry, which can limit the mass flow and volumetric flow accuracy when highly variable (multi-product) liquid properties flow through the same pipeline.

If this meter is ordered with the Type 3 hardware and program configuration, it will have the ability to accommodate clamp-on RTDs, or an analog input from a temperature transmitter. With an active measurement of liquid temperature the meter can then be programmed to compensate for changes in liquid density and viscosity by mean of a “UniMass” table.

SITRANS FUS1020 flowmeters

The FUS 1020 system has the same basic function of the FUS1010 system, but does not include the same I/O capability or safety approval rating of the FUS 1010. This low cost meter is intended for single liquid applications that do not require these additional features.

SITRANS FUS1010 Portable meters

The FUP1010 meter has all the capabilities of the FUS1010 meter, but in a battery powered portable configuration. This meter is ideal for general flow survey work where high accuracy is required. Note that the FUP meter is not available with hazardous areas approvals.

SITRANS FUE1010 Energy meters

By combining clamp-on transit-time flow measurement with accurate temperature differential measurement, the FUE1010 system provides a solution to thermal energy metering with no interruption of service. Energy measurement can be provided for water, ethylene glycol and brine solutions or steam condensate.

Absolute and differential temperature measurement is accomplished with the use of 2 matched 1 kΩ RTD elements installed on the supply and return side of the heating or cooling system. Efficiency calculation (kW/ton, EER or COP) is also available in systems with the optional analog input capability, which allow the meter to accept a power meter output.

The FUE1010 system is available in both dedicated (IP 65 NEMA 4X) and portable configurations.

SITRANS FUG1010 Gas meters

This unique Clamp-On gas meter uses the same WideBeam transit-time operating principle described above. However, due to the very low density and sound velocity characteristics of gases, this meter requires a high gain signal amplifier and the installation of a pipe damping material.

The pipe damping material consists of an adhesive backed viscoelastic film that is designed to attenuate any stray acoustic transmit energy that may otherwise interfere with the transit-time gas signal. Damping material installation requires a clean (grease free) pipe surface with well bonded paint.

The Clamp-On gas meter is capable of operation on most gases (natural gas, oxygen, nitrogen, carbon monoxide, etc) with a typical minimum operating pressure of 10 barg (145 psig). Low molecular weight gases such as helium or hydrogen can also be measured, but at a higher minimum pressure. Be sure to contact a Siemens clamp-on specialist before placing a gas system order.

Standard volume computation: The FUG1010 gas meter is not designed with the same capabilities of a volume compensating flow computer but it can provide a standard volume or mass flow output for fixed gas compositions. All FUG 1010 Gas meters include analog input capability that can be used for pressure and temperature compensation. With the installation of an AGA8 lookup table this meter can dynamically adjust the compressibility factor (Z_act) in response to changes in gas pressure and temperature, as indicate below:

SITRANS FUH1010 Hydrocarbon meters

There are two models of flowmeters included in the 1010FUH family, a viscosity compensated model, used for applications that will flow a wide range of viscosity, and a standard volume (Mass) model. Both models rely on a variable referred to as “liquident”, which is used to infer the liquid’s viscosity and optionally the liquid’s density. This variable represents the measured liquid sonic velocity compensated by the operating temperature and pressure, so for a given liquid product the measured liquident output will remain constant over a wide range of pressure or temperature.

PV (Viscosity Compensation) Option:

This is the lower cost FUH meter option that uses the liquident variable to infer only the actual liquid viscosity. This meter does NOT provide the standard volume, mass flow, liquid identification or density output available in the DV meter option described below. The PV meter is suitable for any petroleum application where actual volume required as the input to an external RTU or flow computer.

DV (Standard Volume) Option:

This Liquident variable can also be used to identify the liquid‘s name (gasoline, fuel oil, crude oil, etc) as well as it’s physical properties (specify gravity, API, viscosity and compressibility) at base conditions. With this information the meter can be configured to output a temperature and pressure compensated (Standard) volume flow rate using the API 2540 and API MPMS chapter 11.2.1 methods as shown below.

Available outputs from this meter include: API, Density, Mass Flowrate, Standard Volume Flowrate and Liquid Identification.

B (Interface Detection) Option:

This meter option is designed to provide all the Non-Flow capabilities of a DV meter, making it an ideal non-intrusive alternative to a densitometer, interface detector or pig detector. Be aware that this meter does NOT measure flow rate.

General Installation Guidelines for transit-time Clamp-On Transducers

• Minimum measuring range: 0 to ± 0.3 m/s velocity (see meter accuracy graph below for more detail)
• Maximum measuring range: 0 to ± 12 m/s (± 30 m/s for high precision transducers). Final flow range determination requires application review
• For very low flow rates on small diameter lines (< DN 25 or 1 inch) a special order inline FlowTube may be recommended. Consult sales specialist for details

• Pipe must be completely full within the transducer installation volume for accurate flow measurement!
• Typical MINIMUM straight pipe requirements are: 10 Diameters upstream / 5 Diameters downstream. Additional straight run is required for double out-of-plane elbows and partially open valves. A minimum of 20 upstream diameters is recommended for clamp-on gas systems
• Transducers should be installed at least 20° off vertical for horizontal pipes. This reduces the chance of beam interference from gas buildup at the top of the pipe
• Operation inside the Reynolds transition region, between 1000 < Re < 5000 should be avoided for best accuracy
• Submersible and direct burial installations can be accommodated. Consult sales representative for details
• Ultrasonic coupling compound is provided with all transducer orders. Insure that a permanent coupling compound is used for long term installations
• Refer to the “Transducer Selection Guide” to insure proper application of the equipment

Чертеж

FUS1010, FUH1010 and FUG1010 IP65 (NEMA 4X) Enclosure

FUS1010, FUH1010 and FUG1010 IP65 (NEMA 7) Compact explosion proof enclosure

FUS1010, FUH1010 and FUG1010 IP66 (NEMA 7) Wall mount explosion proof enclosure

FUP1010 IP67/63 (NEMA 6/3R) Weatherproof impact resistant enclosure

FUP1010 IP40 (NEMA 12) Standard portable enclosure

FUE1010 IP40 (NEMA 12) Portable impact resistant enclosure

FUS1020 IP65 (NEMA 4) Wall mount enclosure