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I
M
NSTRUCTION
ANUAL
FIBER-OPTIC PRESSURE TRANSDUCER
FOP Series
Roctest Limited, 2020. All rights reserved.
This product should be installed and operated only by qualified personnel. Its misuse is potentially dangerous. The
Company makes no warranty as to the information furnished in this manual and assumes no liability for damages resulting
from the installation or use of this product. The information herein is subject to change without notification.
Tel. : 1.450.465.1113 • 1.877.ROCTEST (Canada, USA) • 33 (1) 64.06.40.80 (Europe) • www.roctest.com • www.telemac.com
E10160-200722
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Table of Contents
Troubleshooting
Related Manuals for ROCTEST FOP Series
Summary of Contents for ROCTEST FOP Series
- Page 1 Company makes no warranty as to the information furnished in this manual and assumes no liability for damages resulting from the installation or use of this product. The information herein is subject to change without notification. Tel. : 1.450.465.1113 • 1.877.ROCTEST (Canada, USA) • 33 (1) 64.06.40.80 (Europe) • www.roctest.com • www.telemac.com E10160-200722...
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Page 2: Table Of Contents
TABLE OF CONTENTS PRODUCT ............................1 GAUGE CONSTRUCTION FOP .................... 1 Models FOP and FOP-C ......................2 Model FOP-P ........................... 2 Model FOP-F ........................... 2 Model FOP-MicroPZ and FOP-PZ ..................2 CALIBRATION ........................... 3 FOP SPECIFICATIONS ....................... 3 Filter types ..........................4 FOP-M PZ SPECIFICATIONS .................... - Page 3 FOP ........................20 EADING THE ............................. 20 XAMPLE ................... 21 ETERMINATION OF THE AUGE ACTOR TROUBLESHOOTING ........................22 ......................22 IBER OPTIC READOUT UNIT Battery charge and discharge cycles for portable readout unit ..........22 Cleaning the connectors ......................22 ................
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Page 4: Product
FOP-microPZ and FOP-PZ. These factors are determined through factory calibration. Complete data logging systems are available, please consult Roctest website for details. 1.1 GAUGE CONSTRUCTION of FOP The design of the pressure sensor is based on a non-contact measurement of the deflection of a stainless steel diaphragm, as opposed to the more conventional measuring of the diaphragm’s deformation. -
Page 5: Models Fop And Fop-C
E10160-200722 universal readout unit from Roctest is directly in engineering units either in imperial (psi) or SI (bar) system. Models FOP and FOP-C The model FOP piezometer is designed to be embedded in earth fills and concrete, or inserted into boreholes and pipes as small as 19 mm (3/4”). One end is fitted with an insert that holds a micrometric high air or low air entry filter. -
Page 6: Calibration
E10160-200722 advantage of this model is his ability to be protected against all forms of corrosion as there is no metallic part on the sensor. 1.2 CALIBRATION All piezometers are individually calibrated before shipment. Each piezometer is tested over its working pressure range and they are tested in temperature (except FOP micro-PZ and FOP-PZ). -
Page 7: Filter Types
E10160-200722 CONSTRUCTION Model: FOP-P FOP-C FOP-F Housing: Miniature Push-in Threaded Thick wall (1/4-18NPT point with female EW thread standard) 17-4 PH Stainless steel Diaphragm Material: 33.4 25.4 Outside diameter in mm: 3 or 7mm Cable diameter: Filter types Two types of filters are available: high air entry ceramic or low air entry sintered stainless steel filters. -
Page 8: Fop-Micropz Specifications
E10160-200722 1.4 FOP-MicroPZ SPECIFICATIONS Range 100, 200, 350 (standard range), 500, 750, 1000 kPa Accuracy ± 0.5% F.S. Resolution 0.065% F.S. Overload 1.5x F.S. Outer diameter 4.8 mm Length 54 mm Body material Stainless steel 316 Cable PVC 3 mm outside diameter Stainless steel 316 (porosity 40 μm) Filter 1.5 FOP-PZ SPECIFICATIONS... -
Page 9: Data Reading And Analysis
Before using a transducer with the Universal fiber-optic readout unit from Roctest and Fiso Technologies, its gauge factor must first be saved in the readout memory and selected. The calibration factor is already recorded in the transducer's gauge factor, which is registered on a label installed on the cable close to the fiber-optic connector and you can also find it on the calibration sheet of the gauge. -
Page 10: Fop-Micropz And Fop-Pz Initial Reading
E10160-200722 Take a pre-initial reading in air with the stainless steel filter removed at a stabilized temperature and at a known barometric pressure (for ceramic filter see section 3.1.2 and 3.2). Record the reading, the temperature reading and the barometric pressure reading. Do not touch the transducer body with your hand because you will change the temperature of the transducer and you can see a variation of the reading. -
Page 11: On-Site Function Check (Optional)
E10160-200722 assign the gauge factor 0001000 for all gauges. Do not do any zero adjustment or nulling to adjust the zero. You should follow the same step as described in section 2.2 for initial reading without removing the filter however. After selecting gauge factor 0001000 you should have a reading between 10000 and 23000. -
Page 12: Polynomial Pressure Equations For Fop-Micropz And Fop-Pz Piezometers
E10160-200722 80°F 29.8 in. Hg 29.4 in. Hg 22.25 - 0.01879 (80 - 65) - 0.491 (29.4 - 29.8) corr 22.25 - 0.282 + 0.196 = 22.16 psi corr SI units (bar) – T - CT (T ) - (B corr where: corrected pressure in bar... -
Page 13: Equation With Temperature Compensation
E10160-200722 Standard piezometers are sealed and unvented. Consequently they respond to barometric changes. However this response will vary depending how they are installed. If they are buried or installed in a sealed borehole, it is likely that full effect of the barometric changes will not be felt immediately. - Page 14 E10160-200722 7.978174494E-07 -1.267945332E-10 Pressure unit Considering the following initial condition without any pressure applied on the sensor at the atmospheric pressure. = 16924 nm 20°C 100.2 kPa Then first we must compute the initial recorded pressure P rec0 = c3 (L -Lc) + c2 (L -Lc)
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Page 15: Linear Pressure Equation For Piezometers With Gauge Factor 0001000
E10160-200722 Now I can compute the corrected pressure using the formula. – T = (P ) - CT (T ) - (B corr rec1 rec0 = (514.28 – 99.56) – (-0.0422) (25 – 20) - (101.3- 100.2) corr = 414.72 + 0.211 – 1.1 corr = 413.831 kPa corr... -
Page 16: Installation
E10160-200722 3 INSTALLATION Fiber optic piezometers can be installed in various ways to suit each individual application. Specific guidelines for the installation of piezometers have been set for piezometer installation by various agencies and specialists. A list of references is given in appendix. The following instructions summarize the generally accepted practice for: ... -
Page 17: Initial Reading After Installation
E10160-200722 With the piezometer submerged, firmly grasp the housing with both hands and push the filter assembly into its tip. Gradually increase the pushing force using thumbs until it is fully inserted. This step may take a while to be completed. Some resistance will be met;... -
Page 18: Installation In Fill
E10160-200722 In non – or partially – saturated soils, one should not expect to read exactly 0 kPa after installation because of the above mentioned factors, and because of the potential suction in the soil and potential air infiltration in the piezometers in the case where these are fitted with low-air entry filters. -
Page 19: Installation In Boreholes
E10160-200722 around the instrument and increase the particle size as the backfill proceeds outwards to the rock fill. The sand placed in the recess around the instrument and cable should range in size from 0.5 mm to 2.5 mm in diameter. 3.4 INSTALLATION IN BOREHOLES The method used to install a piezometer in a borehole depends on the particular conditions in which the installation must be carried out. - Page 20 E10160-200722 Tamping of compressed bentonite is not required. Prior to setting the sand in place, lower a cylindrical weight down the borehole to ensure that it is clear from any obstructions and, if necessary, rinse the borehole until clear water emerges. Note: It is also possible to place the piezometer into a sand filled canvas bag.
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Page 21: Cable Identification
E10160-200722 Suggested Grout Mixes Material Ratio by Soil Hardness Material Ratio by Soil Hardness weight weight Portland Cement Hard to Medium Portland Cement Soft Bentonite Hard to Medium Bentonite Soft Water Hard to Medium Water Soft See article from Marefat, Contreras for more information about this technique of installation. -
Page 22: Relation Between Gauge Factor And Calibration Factor
E10160-200722 Use a combination of horizontal and vertical snaking at transition zones. The trench dimensions should be 25 cm wider than the laid out width of the cable. The trench should be a minimum of 60 cm deep. A 12 cm bedding layer of minus 0.8 mm sand is placed along the trench bottom. -
Page 23: Example
E10160-200722 All these digits serve to calculate the relation from cavity length variation in nm to psi with the following equation: 4.1 Reading the FOP Reading the pressure with the FOP is simply made by connecting the FOP, entering the gauge factor and performing a NULL GAUGE in a fiber optic readout unit such as DMI, UMI or FTI models. -
Page 24: Determination Of The Gauge Factor
E10160-200722 From these results, the pressure in psi can be calculated back using the equation described in the previous section and the FOP gauge factor. Calibration factor determination Cavity length variation 17152.0 – 18190.5 = –1038.5 nm Pressure calculation ... -
Page 25: Troubleshooting
-Even though you have fully recharged the battery before storing, you must do it every 6 months. Notice: When the battery dies, contact Roctest to arrange the return of your equipment for battery replacement. Battery life / runtime*: Time your FTI-10 will run before it must be recharged. -
Page 26: Fiber Optic Piezometers Troubleshooting
However, we recommend cleaning the input connector of the readout unit also occasionally. Use the specially designed 2.5-mm Mini Foam Swab for cleaning the input connector. Contact Roctest if you need a cleaning kit. We also recommend to do a visual inspection of the fiber optic connector using a portable optical microscope to inspect for dirt and damage (for more information see the following link https://www.thefoa.org/tech/ref/testing/test/scope.html). - Page 27 E10160-200722 is below 25 % of its full capacity. No transducer connected to the readout or improper connection. Verify connections or clean transducer connector and input connector. Check connector with a microscope. (see section 5.1.2). If you suspect the connector, cut it and replace it by a new one and test again if you get a signal value.
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Page 28: Other Troubles
If pressure variations are suspicious, check if those variations are correlated with recorded temperature and barometric pressure. Check if corrections to raw pressure are applied correctly. Try to perform a calibration on-site and contact Roctest with reading for evaluation. 6 MISCELLANEOUS REFERENCES: Terzaghi, K., and R. - Page 29 E10160-200722 Hanna, T.H. Foundation Instrumentation, Trans. Tech. Publications, Ohio, USA, 1973. (Chapter 3 describes different types of piezometer tips, methods of installation, methods of recording and the protection of piezometers.) Clements, D. J., and A. C. Durney (1982), Instrumentation Developments, proceedings of the Autumn Conference on the British National Committee on Large Dams (BNCOLD) Keele University, Institution of Civil Engineers, London, pp.
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