Flow Metering that Outperforms in the Most Demanding Environments
HHR Flow Tube • A technological advancement in differential pressure flow metering.
• Lowest Operating Cost
• Highest Head Recovery
• More efficient than an ASME Nozzle
• Lowest Uncalibrated Error
• Rugged Fabricated Construction
The High Head Recovery (HHR) Flow Tube is the most efficient differential producing flow measuring device available. The HHR Flow Tube provides significant savings in recurring operation costs over any other type of primary flow element including the venturi tube. In addition to low permanent pressure loss, the HHR Flow Tube is probably the most efficient primary device available in terms of passing flow with an average coefficient of discharge of 0.9872. Calibration reports on the HHR Flow Tube consistently show less error than in the flow calibration of any other type of differential pressure producing primary flow element. These characteristics, combined with superior fabricated construction, make the HHR Flow Tube an ideal choice for flow measurement where accuracy, long life and low operating costs are important.
HIGHEST ACCURACY / PROVEN PERFORMANCE  •  The HHR Flow Tube delivers proven performance based on extensive laboratory and field testing.
Over 1500 flow calibration points from Alden Research Laboratory show the coefficient of discharge to be constant, independent of Reynolds Number and within + 0.50% of the predicted value. This accuracy can only be maintained when FTI recommendations are used with regard to upstream piping requirements. Each FTI Flow Tube throat section is machined to provide the smoothness and roundness necessary to ensure that these accuracy limits are met. Throat forgings are lengthened to allow machining of the transition angle from the throat to the cone, eliminating the possibility of error due to the grinding of the cone throat weld.

When a higher degree of accuracy is desired, the Flow Tube can be flow calibrated after manufacture to establish an exact differential pressure range for the flow range desired. The accuracy of this data is dependent on the flow laboratory used. FTI recommends the use of
a laboratory whose data are NIST certifiable to an accuracy of + 0.25%
ENERGY EFFICIENCY  •   The HHR Flow Tube provides superior energy efficiency and reduced operating cost.
Low permanent pressure loss (PPL) equates to energy efficiency and reduced operating cost. The HHR Flow Tube has a lower permanent pressure loss than the orifice plate, annular orifice, flow nozzle or venturi meter. In an orifice plate the flow impacts with an abrupt surface and typically results in a PPL of 2 psig. For enhanced pressure recovery the HHR Flow Tube has a smooth, contoured, obstruction free entrance with a pressure recovery cone. In many cases the recurring operating cost savings offered by the HHR Flow Tube in such applications as high pressure, high temperature steam can actually pay for itself in a very short period of time.
APPLICATION VERSATILITY  •  Precision measurement in gas, liquid, steam, chemical, sludge and slurry.
The HHR Flow Tube is suitable for precision flow measurement in gas, liquid, steam, chemical, sludge and slurry applications. Wide range (pipe Reynolds Number as low as 200,000), high pressure recovery, repeatability, sustained accuracy and short upstream piping requirements make it the preferred meter in many installations.
QUALITY CONTROL AND CERTIFICATIONS  •  Manufactured under the strictest controls and highest standards.
FTI maintains quality control at all points from receiving inspection of materials to final inspection of the finished product. Measurements of all critical dimensions are recorded and kept on file for five years.

FTI maintains a full range of qualified weld procedures to ASME Section IX standards using SMAW, SAW, GTAW, and FCAW processes. FTI holds ASME Power Piping (PP), CE/PED and CRN certifications. Complementing our special emphasis on welding techniques and equipment, the FTI inspection department is qualified to AWS-QC1 standards.

FTI offers a full range of Nondestructive Testing options. In house capabilities include Gamma Radiography & Dye Penetrant Testing. On staff NDE Level II & Level III personnel are certified to ASNT recommended practice SNT-TC-1A. All other NDE disciplines are available to FTI through 3rd party sub-contracting.
Other special services include but are not limited to Postweld Heat Treatment, Hydrostatic Pressure Testing, Positive Material Identification and Ultrasonic Thickness Checking.
Fluidic Techniques meets the requirements of the International Organization for Standardization and is ISO 9001 / 2008 Certified.
FTI Flow Tube Construction
ENTRANCE SECTION   The HHR Flow Tube inlet portion consists of a cylindrical section at least one pipe diameter in length. This enables proper location of the high pressure meter tap at the proper distance from the beginning of the nozzle entrance curve.
ENTRANCE CURVE  An elliptical curve is provided between the entrance section and the throat. This curve is machined from a one piece forging and is furnished with a smooth finish to ensure efficiency.
ONE PIECE THROAT   Each HHR Flow Tube is manufactured with a machined one piece stainless steel throat as standard. The transition from the throat bore to the cone angle is also machined to eliminate deformation of the bore due to welding and grinding of the throat-cone weld. Throats fabricated from rolled plate and throat liners are not recommended due to their effect on accuracy and repeatability. The machined HHR throat is furnished with better than 50 micro-inch finish to ensure optimum performance.
EXIT CONE  The exit cone is attached to the discharge end of the HHR throat and is either fabricated or machined with all welds and protrusions ground smooth. HHR Flow Tubes are furnished with 15o exit cones.
EXIT SECTION  To facilitate field welding and installation, a cylindrical straight section matching the adjacent piping is furnished on all weld-in style HHR Flow Tubes
FLANGES  Flanged HHR Flow Tubes are provided with raised face weld neck flanges on each end as standard.
DIFFERENTIAL PRESSURE CONNECTIONS All FTI HHR  Flow Tubes are furnished with one high pressure and one low pressure 1/2'' NPT 3000# threadolet as standard. Full penetration weld adapters, socket weld connections, higher ratings and other sizes of threaded connections are available. HHR tubes are also available with multiple tapsets.
MATERIAL OF CONSTRUCTION  Both fabricated and machined HHR Flow Tubes are available in carbon steel, stainless steel, or other metals. When required, materials can be furnished as required by the ASME Boiler and Pressure Vessel Code or other piping codes.
METHOD OF CONSTRUCTION  In line sizes up to and including 5'', all FTI HHR Flow Tubes are machined from round bar material with flanges (if required) welded to each end. Most HHR Flow Tubes in line sizes from 6'' and above are of fabricated construction.
QUALITY CONTROL  HHR Flow Tubes are manufactured to exacting standards in a modern manufacturing facility under strict quality control. All welding is accomplished by code certified welders.
FTI’s in-house testing capability includes radiography, hydrostatic and other nondestructive tests. FTI holds the ASME Pressure Piping (PP) Certificate of Authorization. Special welding and quality procedures are available as required.
UPSTREAM PIPING RECOMMENDATIONS
(Reference —ASME MFC-3M-2004)

Diameter
Ratio, ß
Single 90o
Bend
(Note 1)
2 or More 90o
in Same or
Different Planes
(Note 1)
Reducer
1.33D to D
Over Length
of 2.3D
Expander
0.67D to D
Over Length
of 2.5D
Reducer
3D to D
Over Length
of 3.5D
Expander
0.75D to D
Over Length
of D
Full Bore Ball
or Gate Valve
Fully Open
1
2
3
4
5
6
7
8
A
B
A
B
A
B
A
B
A
B
A
B
A
B
0.30
8
3
8
3
4
Note (2)
4
Note (2)
2.5
Note (2)
2.5
Note (2)
2.5
Note (2)
0.40
8
3
8
3
4
Note (2)
4
Note (2)
2.5
Note (2)
2.5
Note (2)
2.5
Note (2)
0.50
9
3
10
3
4
Note (2)
5
4
5.5
2.5
2.5
Note (2)
3.5
2.5
0.60
10
3
10
3
4
Note (2)
6
4
8.5
2.5
3.5
2.5
4.5
2.5
0.70
14
3
18
3
4
Note (2)
7
5
10.5
2.5
5.5
3.5
5.5
3.5
0.75
15
8
22
8
4
Note (2)
7
6
11.5
3.5
6.5
4.5
5.5
3.5
NOTES:
1. The radius of curvature of the bend shall be greater than or equal to the pipe diameter.
2. The straight length in each Column A gives zero additional uncertainty, data are not available for shorter straight lengths that could be used to give the required straight lengths for each Column B.
3. Column A for each fitting gives lengths corresponding to “zero additional uncertainty” values.
4. Column B for each fitting gives lengths corresponding to “0.5% additional uncertainty” values.
Energy Efficiency •  Cost Effective
The FTI HHR Flow Tube is one of the most efficient differential pressure producing flow measurement devices available. It has lower permanent pressure losses (PPL) than an Orifice Plate, Annular Orifice, or Flow Nozzle as shown in the graph.

HIGH HEAD RECOVERY FLOW TUBE COEFFICIENT OF DISCHARGE
VS. PIPE REYNOLDS NUMBER
Pipe size: All RD Range:*10^6 / All Average CD: 0.9872 / STD DEV: 0.0050 / Correlation: 0.1467
Shown above are the results of over 700 calibration runs of the FTI HHR Flow Tube. The data produces an average coefficient of discharge of 0.9872 with standard deviation of 0.0050. The data illustrates that for Reynolds numbers greater than 200,000 the coefficient of discharge is independent of Reynolds number. The data shown represents a wide range of tests including various line sizes, beta ratios and Reynolds numbers.
The coefficient of discharge is a measure of efficiency of a primary element and represents the actual flow rate versus the theoretical flow rate. A coefficient of discharge of 1 would be the most efficient possible. The high coefficient of discharge allows the HHR Flow Tube to be used with the lowest differential pressure ranges of any primary element device.

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.

FTI model number
Line size
Pipe schedule or actual I.D.
Differential pressure at maximum flow
Material of construction for body and throat
Flange, type and rating (if applicable)
Flowing medium
Maximum flow (specify units)
Operating pressure and temperature at maximum flow
S.G. @ 60o base pressure and temperature
S.G. @ flowing conditions (liquid)
Compressibility factor @ operating pressure and
base conditions (gas)
Molecular weight (gas)
Viscosity
APPROXIMATE DIMENSIONS FOR FTI HHR FLOW TUBES
Notes:
1. HHR-F weights calculated on the basis of using 150# RFWN flanged ends.
2. Above flow tube weights and lengths are based on Schedule Standard Pipe and 375'' thick flow tube walls.
3. Weights and lengths are approximate.
4. Weights and lengths of HHR-I insert type flow tubes vary with line I.D. Consult factory.

®

Fluidic Techniques Division of FTI Industries, Inc..
1213 Antlers Drive, Mansfield, TX 76063 USA
Tel: (817)473-4481 • Fax: (817)473-6318