INSTALLATION, OPERATION and MAINTENANCE MANUAL for FLOTEC SENSOR

Transcription

1 di Wika Italia Srl Sas Via G. Borghisani, PIEVE S. GIACOMO (CR) ITALY Tel.: Fax: euromisure@euromisure.it IM-FLO-E-10/02 Pagine Documento Document Pages 16 IM INSTALLATION, OPERATION and MAINTENANCE MANUAL for FLOTEC SENSOR Mod. S-730 Mod. S-750 Mod. S-755 Mod. F-730 Mod. F-750 / F-780 Mod. F-755 / F-785 Mod. EM-730 Mod. EM-750 / EM-780 Mod. EM-755 / EM-785

2 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 2 IM INDEX 1) Scope 2) General Description of the FLOTEC Device 3) Operating Limitations 4) Selecting Mounting Location 4.1 Straight Run Requirements 4.2 Relation to Readout Device 4.3 Pulsation & Vibration 4.4 Position in the Pipe Liquid Flow Measurement Air / Gas Flow Measurement Steam / Vapor Flow Measurement 5) Installation Instruction 5.1 Model S with Coupling, Gland, Packing and Threaded Ferrule FLOTEC Model S-730 and S-750 (without opposite support) FLOTEC Model S-755 (with opposite support) 5.2 Model F with Flanged Mounting Nozzle FLOTEC Model F-730, F750 and F-780 (without opposite support) FLOTEC Model F-755 and F-785 (with opposite support) 5.3 Model EM with Flanged Mounting Nozzle Extractable Type FLOTEC Model EM-750 and EM-780 (without opposite support) FLOTEC ;Model EM-755 and EM-785 (with opposite support) 6) Insertion / Extraction System for Extractable Type FLOTEC ( EM Model) 6.1 Insertion of the FLOTEC Sensor 6.2 Extraction of the FLOTEC Sensor 7) Meter Connection and Location 7.1 General Requirements 7.2 Requirements for Liquid 7.3 Requirements for Air and Gas 7.4 Requirements for Steam 8) Purging 8.1 Periodic Purging 9) Maintenance 10) Interchangeability 11) Troubleshooting Guide 11.1 Questionable Accuracy 11.2 Low Signal 11.3 Spiking Signal

3 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 3 IM 1) SCOPE This manual describes the general functioning principles and the essential safety requirements for the handling, the installation, the use and the maintenance of the standard FLOTEC shown on page 1 and codified as per follow description : Mounting type: S: Coupling with gland, packing and threaded ferrule F: Flanged mounting nozzle EM: Flanged mounting nozzle extractable type under process condition. Series: 73: suitable for small pipe diameter, low-stress conditions 75: suitable for medium pipe diameter, medium-stress conditions 78: suitable for large pipe diameter, high-stress conditions Application of opposite support (if required): Suffix 0 (Model type xx0): without opposite support Suffix 5 (Model type xx5): with opposite support (Not Applicable for Series 73) The choice of the applicable model is based on the vibration / frequency due to the process conditions. The high capacity FLOTEC models (F-790 and F-795), suitable for strongest process conditions are not in the scope of this manual. 2) GENERAL DESCRIPTION OF THE FLOTEC DEVICE The FLOTEC is based on the classical Pitot tube rule, but the average upstream velocity (and as consequence the average upstream pressure) is taken from 4 different pressure taps (dynamic) located in defined positions on the upstream edge of the square-bar of the FLOTEC. While the static pressure tap (downstream pressure) is located on the downstream edge of the square-bar of the FLOTEC, in the centre of the pipe line diameter. The difference between the dynamic and static pressure taps is the measured Dp of the device. Like all the others flow measurement, the applicable equation for the FLOTEC is the follow: Q Fm Dp Gf where Q is the volumetric flow rate, Fm is a correction factor for dimensional units which includes a discharge coefficient to correct for the characteristics of the construction, Dp is the pressure difference between the measured upstream and downstream pressures, Gf is the density of the fluid. The condition necessary to obtain an accurate flow rate measurement is to have stable flow rate, pressure and temperature states. 3) OPERATING LIMITATIONS Structural limitations based on differential pressure are included in the here below Graph 1, for temperatures up to 93 C. For higher operating temperatures, reduce the maximum allowable differential pressure (Dp) by 3% each 38 C from 93 C to 400 C. These values are applicable for AISI 316 / AISI 316L (Stainless Steel) FLOTEC sensor material only.

4 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 4 IM 4) SELECTING MOUNTING LOCATIONS Correct location of the FLOTEC in the pipeline is important because disturbance in flow by pipe layout may affect the accuracy of measurement. The following standard practices should be reviewed before selecting a mounting location : 4.1 Straight Run Requirements Table 1 here below shows recommended approach and depart values in terms of straight pipe diameters for normal industrial metering work. For laboratory or high accuracy work, add 25% to the values shown. Use of recommended straight pipe lengths of uniform diameter upstream and downstream in sures that flow measurements will be made in flow with fully-developed characteristics. Straightening vanes may be used to reduce the length of straight pipe required in many cases. Table 1 1) Exceptions : Field experience has proven that FLOTEC produces a repeatable signal even in pipes with less than the recommended upstream and downstream straight pipe. In such cases, FLOTEC is an effective flow sensor for control and other applications where repeatability is the most important factor. 2) Pos.6 includes gate, globe, plug, and other throttling valves that are only partially opened. If valve is to be fully open, use values shown on Pos. 4 or 5. Control valves should be located after FLOTEC element.

5 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 5 IM Table 1 - Upstream and Downstream straight run pipe requirement (multiple of internal pipe diameter D) 4.2 Relation to Readout Device The distance between the meter (Dp transmitter) and the FLOTEC should be as short as possible. If the distance from meter to sensor is under 50 feet (15 m), 1/4 " OD tubing is satisfactory. For each additional 50 feet (15 m), use tubing 1/8" larger in size.

6 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 6 IM 4.3 Pulsation & Vibration Avoid the location of the FLOTEC in pulsating flow. This may result in "noisy" signal problems. Vibration can also distort the output signal and compromise structural limits of the FLOTEC. Mount the FLOTEC in a secure, stable run of pipe to obtain optimum signal output. 4.4 Position in the Pipe FLOTEC may be installed in any plane of the pipe ( horizontal, vertical, 45, or any angle in-between). However, for trouble free operation, consideration must be given to the type of fluid and the secondary instrumentation LIQUID FLOW MEASUREMENT For vertical pipes, the FLOTEC can be installed in any position of the 360 circumference of the pipe. For horizontal pipes, it is suggested to install the FLOTEC into the bottom side (see Fig.1) so that the instrument connections are below the pipe center line. This will keep the instrument lines full of liquid and encourage air or gas that may be in the instrument tubing to find its way to the sensor and thus into the flowing fluid. For liquid applications is necessary to vent the trapped air (or gas) in the instrument before to do a flow measurement. In case of big dimensions pipe and/or underground applications the FLOTEC must be mounted vertically AIR / GAS FLOW MEASUREMENT On vertical pipes, the FLOTEC may be installed in any position of the 360 circumference of the pipe. For horizontal pipes, the FLOTEC should be installed so the instrument connections are above the pipe center line (see Fig.2). This is to prevent moisture or condensation from entering the connecting lines. In case of big dimensions pipe and/or underground applications the FLOTEC must be mounted vertically. Fig. 1 Installation of FLOTEC in horizontal pipe for LIQUID Fig. 2 Installation of FLOTEC in horizontal pipe for AIR / GAS

7 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 7 IM STEAM / VAPOR FLOW MEASUREMENTS On vertical pipes, the FLOTEC may be installed in any position of the 360 circumference of the pipe, with the instrument connections on the same horizontal plane (see Fig.3). FLOTEC for vertical steam lines must be manufactured with instrument connections at right angle to flow direction. For horizontal pipes, install the FLOTEC in the above side of the pipe (see Fig.4). Steam flow measurement requires special consideration for successful operation (see Para 7.4). Fig. 3 Installation of FLOTEC in vertical pipe for STEAM Fig. 4 Installation of FLOTEC in horizontal pipe for STEAM 5) INSTALLATION INSTRUCTIONS 5.1 MODEL S WITH COUPLING, GLAND, PACKING AND THREADED FERRULE FLOTEC Model S-730 and S-750 (without opposite support) sketch No. 1 2 / 3 / ) Drill or burn a 35 mm hole in pipe for furnished mounting coupling. 2) Install threaded ferrule (without gland) on mounting coupling to protect threads during welding.

8 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 8 IM 3) Tack weld mounting coupling to the pipe and align it so it is perpendicular to and intersects the pipe axis. A convenient way to do this is to insert a short piece of 1" diameter stock into the mounting coupling and use it as leverage for alignment. 4) Complete welding 5) Remove threaded ferrule from mounting coupling and slide it onto FLOTEC along with the gland. The short-tapered end of gland should be pointing toward the probe tip so that it goes into the mounting coupling installed in the pipe. Place the packing into the coupling. 6) Insert the FLOTEC along with the threaded ferrule and the gland into the mounting coupling on the pipe. Align the flow arrow on the FLOTEC with the direction of flow and the flats on the FLOTEC head parallel to the pipe axis. Be sure the FLOTEC is touching the back side of the pipe. Tighten the compression nut to 250 lbs. ft. (340 Nm) torque. Approximately one full thread is left exposed under the nut. Use of a 2 to 3 ft. (60 to 90 mm) wrench is normally required. It may be necessary to hold the head of the FLOTEC with a wrench to keep it from rotating while tightening the threaded ferrule. To obtain a good measurement you must respect the tolerance indicated at Para 9-TROUBLESHOOTING GUIDE FLOTEC Model S-755 (with opposite support) sketch No. 2 / 3 / 4 5 / ) Repeat the operations from 1 to 3 as per FLOTEC Model S-730 and S-750 instructions (5.1.1). 2) Locate position for opposite support coupling by putting a piece of soft wire or string around the pipe. Measure halfway (180 ) around the pipe from mounting coupling and mark center for opposite support coupling. 3) Drill or burn a 35 mm hole at mark for opposite support coupling. 4) Tack opposite support coupling in place. Check for correct alignment by inserting FLOTEC through mounting coupling and opposite support coupling. Remove FLOTEC and complete welding for both coupling. 5) Remove threaded ferrule from mounting coupling and slide it onto FLOTEC along with the gland. The short-tapered end of gland should be pointing toward the probe tip so that it goes into the mounting coupling installed in the pipe. Place the packing into the coupling. 6) Insert FLOTEC along with threaded ferrule and gland into mounting coupling and through to the opposite support coupling. 7) Screw hex plug into opposite support coupling and guide FLOTEC into it. Use pipe thread compound on it and tighten hex plug until it is secure. 8) Push FLOTEC until it touches bottom of hex plug. Align the flow arrow on the FLOTEC with the direction of flow and the flats on the FLOTEC head parallel to the pipe axis. Tighten the compression nut to 250 lbs. ft. (340 Nm) torque. Approximately one full thread is left exposed under the nut. Use of a 2 to 3 ft. (60 to 90 mm) wrench is normally required.

9 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 9 IM It may be necessary to hold the head of the FLOTEC with a wrench to keep it from rotating while tightening the threaded ferrule. To obtain a good measurement you must respect the tolerance indicated at Para 9-TROUBLESHOOTING GUIDE 5.2 MODEL F WITH FLANGED MOUNTING NOZZLE FLOTEC Model F-730, F-750 and F-780 (without opposite support) The flanged nozzle could be supplied by Euromisure or supplied by piping and in this case the Customer have to give to Euromisure the following informations, mandatory to design in the correct way the FLOTEC: - DN, Rating and the facing type of flanges (RF, FF, RTJ etc.) - The exact height of the nozzle (from flange facing surface to the external surface of the pipe) - The internal diameter of the nozzle have to be 1.3/8 (35 mm) minimum for FLOTEC Models F-730, F- 750 and F-755 and 2.3/8 (60 mm) minimum for FLOTEC Model F-780 and F-785. The flanged nozzle supplied by Euromisure have not a fix distance from the flange facing surface to the external face of the pipe. Usually is 150mm, but it depend from the type of nozzle (weldolet and flange type, or coupling, pipe and flange type) or from the thickness of insulation (the Customer have to inform Euromisure if it is applicable or not) sketch No. 1 / ) If the mounting nozzle is supplied by Euromisure, drill or burn a 35 mm hole for Mod. F-730 and F-750, or 60 mm for Mod. F-780 in pipe. 2) Tack weld mounting nozzle (attention to the position of the holes for bolts) to the pipe and align it so it is perpendicular to and intersects the pipe axis. 3) Complete welding. 4) Insert the FLOTEC into the flanged nozzle (attention to the position of the flow arrow shown on the FLOTEC head) and complete with gaskets and fix with bolts and nuts (this operation is valid also for the FLOTEC with mounting nozzle NOT supplied by Euromisure). to obtain a good measurement you must respect the tolerance indicated at Para 9-TROUBLESHOOTING GUIDE.

10 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 10 IM FLOTEC Model F-755 and F-785 (with opposite support) sketch No. 2 / ) Repeat the operations 1 & 2 as per FLOTEC Model F-730, F-750 & F-780 instructions (5.2.1). 2) Locate position for opposite support nozzle by putting a piece of soft wire or string around the pipe. Measure halfway (180 ) around the pipe from mounting nozzle and mark center for opposite support nozzle. 3) Drill or burn a 35 mm hole for Mod. F-755 or 60 mm hole for Mod. F-785 at mark for opposite support nozzle. 4) Tack opposite support nozzle (attention to the position of the holes for bolts) to the pipe and align it so it is perpendicular to and intersects the pipe axis. The blind flange (and its centering pipe, gaskets and bolts and nuts) have to be mounted on the opposite flanged support. Check for correct alignment by inserting FLOTEC through mounting nozzle and opposite support nozzle. Remove FLOTEC and complete welding for both nozzle. 5) Insert the FLOTEC into the flanged nozzle (attention to the position of the flow arrow shown on the FLOTEC head) and check that the end part of the FLOTEC go into the opposite flanged support. Complete with gaskets and fix with bolts and nuts (this operation is valid also for the FLOTEC with mounting nozzle NOT supplied by Euromisure). To obtain a good measurement you must respect the tolerance indicated at Para 9-TROUBLESHOOTING GUIDE 5.3 MODEL EM WITH FLANGED MOUNTING NOZZLE EXTRACTABLE TYPE FLOTEC Model EM-750 and EM-780 (without opposite support) 1) Repeat the operations from 1 to 4 as per FLOTEC Model F-730, F-750 and F-780 instructions (5.2.1). To obtain a good measurement you must respect the tolerance indicated at Para 9-TROUBLESHOOTING GUIDE FLOTEC Model EM-755 and EM-785 (with opposite support) 1) Repeat the operations from 1 to 4 as per FLOTEC Model F-755 and F-785 instructions (5.2.2). To obtain a good measurement you must respect the tolerance indicated at Para 9-TROUBLESHOOTING GUIDE

11 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 11 IM 6) INSERTION / EXTRACTION SYSTEM FOR EXTRACTABLE TYPE FLOTEC ( EM MODEL) The extractable FLOTEC model, is a flanged mounting nozzle model with the extraction system to insert / extract the FLOTEC under process condition. For safety, the extractable FLOTEC model is NOT applicable if one or more of the following conditions happens in the process: - Lethal fluid - Toxic fluid - Easily flammable fluid - Acids or other fluids that could be dangerous in general for the operator - Operating pressure higher than 200 Bar - Operating temperature higher than 300 C The extraction system is applicable for the following FLOTEC model: EM-750 and EM-780: flanged model without opposite support EM-755 and EM-785: flanged model with opposite support 6.1 INSERTION OF THE FLOTEC SENSOR 6.1 sketch No. 1 / 2 / 3 / 4 5 / 6 7 / 8 / 9 1) Check that the blow-out bleed valve mounted on the packing seat is fully closed 2) Unscrew and lift up the anti-squirt cap 3) Loosen the packing gland without remove it 4) Fully open the isolation valve (usually 1.1/2 ball valve type). Be carefully, because during this operation some fluid may exit from the packing gland; in this case tighten the packing gland till the leakage finished. If necessary, for the operator safety, during the tighten of the packing gland re-close temporarily the isolation valve and re-test again the packing gland seal. 5) Re-screw the anti-squirt cap on its original position and check that the isolation valve is fully open. 6) Turn the hand wheel till the lock-washer welded on the threaded rod (highlighted in red color) reach its end limit (inserted position) 7) Unscrew and lift up the anti-squirt cap 8) Tighten the packing gland 9) Re-screw the anti-squirt cap on its original position.

12 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 12 IM 6.2 EXTRACTION OF THE FLOTEC SENSOR 6.2 sketch No. 1 / 2 / / 6 / 7 / 8 / 9 / 10 1) Unscrew and lift up the anti-squirt cap 2) Loosen the packing gland without remove it. Be carefully, because during this operation some fluid may exit from the packing gland; in this case tighten the packing gland till the leakage finished. 3) Re-screw the anti-squirt cap on its original position 4) Turn the hand wheel till the green band painted on the threaded rod reach its end limit (extracted position). Warning!! Don t close the isolation valve if the green band have not yet reach its end limit, to avoid to damaged seriously the seal of valve against the FLOTEC, not yet completely extracted 5) Only when the point 4) is completed, fully close the isolation valve (usually 1.1/2 ball valve type). 6) Open the blow-out bleed valve to discharge the residual pressure and fluid from the extension nipple of the FLOTEC. Is possible to connect the bleed valve with a discharge tank at site. 7) Unscrew and lift up the anti-squirt cap 8) Tighten the packing gland 9) Re-screw the anti-squirt cap on its original position 10) Close the blow-out bleed valve

13 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 13 IM 7) METER CONNECTION AND LOCATION 7.1 GENERAL REQUIREMENTS Following is a checklist of general instrument practices for meter connecting tubing. Refer to installation instructions provided by the secondary instrument manufacturer to cover all contingencies of your application. 1) Connecting tubing must have a slope of least one inch per foot (25 mm each 300 mm) and must be supported over its entire length to prevent sagging. 2) The two connecting lines should be run close together to maintain equal temperatures. CAUTION : Be sure nylon or rubber lines are kept away from hot lines or other heat sources. 3) Run tubing in protected areas such as conduit, channels, I-beams or angles, against walls or ceilings. Protect horizontal runs near the floor or under work areas with steel sheeting for kick plates. 4) Run tubing where it will be accessible for maintenance. On long runs, tubing should be tagged every 30 to 40 feet (900 to 1200 mm) for easy identification. 5) Tubing must be absolutely airtight. If vibration is expected, set up a periodic inspection procedure for checking all joints for leakage. 7.2 REQUIREMENTS FOR LIQUID Trapped air in the piping system is responsible for the majority of problems associated with liquid flow measurement. Differential pressure must be transmitted from the FLOTEC to the secondary instrumentation through a solid head of non compressible liquid. Installation of the instrumentation below the FLOTEC is preferred for liquid service (see Fig. 5 and 6). Fig. 5 - LIQUID IN HORIZONTAL LINE Fig. 6 - LIQUID IN VERTICAL LINE For horizontal line, when is not possible to mount the FLOTEC under the pipe, it can be mounted above, but in this case a periodic vent of the system is necessary, to avoid the presence of air or gas that could be modify the flow measurement. 7.3 REQUIREMENTS FOR AIR and GAS Differential pressure must be transmitted from the FLOTEC to the secondary instrument without change due to leakage or trapped liquid. For dry air or gas, the secondary instrument may be mounted either below or above the FLOTEC. For wet or dirty air or gas flow, the secondary instrument should be mounted above the FLOTEC, or settling traps should be installed in the connecting lines (see Fig. 7 and 8).

14 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 14 IM Fig. 7 AIR / GAS IN HORIZONTAL LINE Fig. 8 AIR / GAS IN VERTICAL LINE 7.4 REQUIREMENTS FOR STEAM Differential pressure must be transmitted from the FLOTEC to the secondary instrument but the steam must not enter on the transmitter. Fill the system with cool water before pressurizing the system, using a tee connection installed after the valves mounted on the FLOTEC head. The installation of a condensing pot for each pressure tap instead of a tee is suggested. For steam in vertical pipe, the position of the head have to be rotate of 90 respect to the other standard installation, because the head of the FLOTEC have to be perpendicular to the pipe to have the two pressure taps at the same height (see Fig. 9 and 10). Fig. 9 STEAM IN HORIZONTAL LINE Fig. 10 STEAM IN VERTICAL LINE 8) PURGING FLOTEC have been used successfully for measuring flow of very contaminated fluids without purging. Conditions requiring purging are variable, and if the applications is questionable, use without purging and plan to use purging as a back-up. 8.1 PERIODIC PURGING Periodic or intermittent purging is the simplest purging method and should be considered first for contaminated flow measurement. To do this, install an air or steam line to the instrument lines and periodically blow through the element to force out contamination.

15 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 15 IM 9) MAINTENANCE The FLOTEC is virtually maintenance-free. Anyway it should be cleaned in the follow way: 1) Remove the element 2) Flush completely 3) Hand-clean with soft wire brush 4) Rod interpolating and static tubes with a soft wire brush For the extractable type model, lubricate each month the threaded rod and its seats. 10) INTERCHANGEABILITY Each FLOTEC is designed for a particular line size and type installation. The FLOTEC may be inter-changed among different pipes if the pipe size and installation are identical (Internal pipe diameter, thickness of the pipe and heights of the mounting/opposite nozzle). This provides great flexibility, especially when a Flo-Tap FLOTEC is used. The same FLOTEC may be used with different fluids. For example, the same FLOTEC may be used to measure liquid or gaseous propane, air, water or steam, always if the pipe size and installation are identical. The re-calculation of DP to flow conversion is the only adjustment required. FLOTEC is not recommended for two phase(liquid/vapor or liquid/gas) flow measurement 11) TROUBLESHOOTING GUIDE FLOTEC operates on natural scientific principles. No moving parts are used in the design, and wear has negligible effect on accuracy. If installed correctly, FLOTEC will provide a correct flow indication if there is flow in the pipe. To resolve a discrepancy, interpretation of the FLOTEC, signal and other components of the flow system should be examined closely QUESTIONABLE ACCURACY 1) FLOTEC installation : Insure that the FLOTEC flow arrow is pointing directly downstream. FLOTEC accuracy will be influenced by installation misalignment. To insure meeting stated accuracies, alignment must be within the limits shown here below (see Fig. 11). Fig. 11 FLOTEC INSTALLATION MISALIGNMENT LIMITS 2) Pipe Size : The FLOTEC may have been designed for a different pipe size from that in which it is being used. Measure pipe ID and compare with size printed on identification tag attached to the FLOTEC.

16 Sas di Wika Italia Srl IM-FLO-E-10/02 Pagina / Page 16 IM 3) Insufficient straight run : If the FLOTEC is installed in less than recommended straight run pipe length, accuracy may be affected (see Para Table 1 for straight run requirements). 4) Calculations : The calculation for a particular FLOTEC may be in error. Re-check the calculation or graph used for conversion. Changes in operating temperature or pressure are critical on air, gas or steam applications. Re-check the actual operating temperature and pressure compared to the values used in the calculation LOW SIGNAL 1) Leaks : Check for leaks in the instrument piping. Repair and seal all leaks. 2) Contamination / Plugging : Remove FLOTEC and check for contamination. Clean the FLOTEC as shown on Para 9 - MAINTENANCE. If removal is not practical, back-flush through instrument lines or through cleanout ports (plugged with 1/8 NPT on top side of the FLOTEC head) SPIKING SIGNAL 1) Pulsating Flow : If FLOTEC is installed in this condition, the signal will reflect the flow condition with a spiking signal. If unable to relocate, mechanical pressure snubbers in the instrument lines or electronic damping may alleviate this problem. 2) Two-Phase (Liquid/Vapor) Flow : Two-phase or alternating-phase flow will cause an erratic spiking signal. FLOTEC is a head measuring device and will not accurately measure two-phase flow.