MF500M+ manual
Contents
1. pipe fills up from the bottom rather than homogeneously as per our occlusion calculations Under these conditions we would recommend probing the underside the side and the top of the pipe around the circumference Due to the proximity of other pipes the underside and top of the pipes may not be accessible so we recommend probing positions A B and C in the Figure 2 As the pipe fills up the signal is expected to increase on A first then B and finally C Note the meter must be zeroed between measuring points A B and C but not between the same orientations on the same or different pipes Page 9 www diverse technologies net Measurement technique We recommend that a number of pipes are surveyed and the measurements correlated with magnet tests and x ray data From these results a measurement rational should be evident that allows pipes with a particular occlusion to be readily identified using the meter An alternative formal rote is described in the following section C A Figure 2 Pipe measurement Page 10 www diverse technologies net Calculation of Magnetite from MF500M readings Preamble The magnetite meter measures the force on a powerful rare earth magnet caused by the ferritic component of the magnetite It is a prerequisite of this technique that the containing pipe is stainless steel which is not magnetic In making the measurement the instrument has a sensor that has some compensation for the p2. easurement Zero the probe before each measurement Quick start 1 Plug in the magnetite probe 2 Load the AA batteries in to the battery compartment ensuring that the polarity is correct 3 Press the power button central yellow button the unit will switch on 4 Hold probe away from pipe and depress button on probe until a long beep is heard zero value stored 5 Take probe to pipe and press button a double beep will indicate measurement has been taken For a more detailed description of functionality see the operation section Important note The probe end should be placed no closer than 5mm to steel or iron as this will stress the detector Page 4 www diverse technologies net Operation Controls There are 5 buttons on the meter and one on the probe with functions as given in table 1 Table 1 Button functions enter yellow long press to turn unit off short press to turn on or select subsidiary function e g view records etc up green scroll through records in lt view records gt menu toggle display type in lt measure gt menu down green scroll through records in lt view records gt menu toggle display type in lt measure gt menu and leave subsidiary menus and leave subsidiary menus Probe black probe short press take measurement and record button long press store current value as zero offset Button presses are accompanied by audible confirmation as follows e single bee
3. enter to clear records and set next record pointer to start of memory lt About gt Gives software version number lt Calibrate gt The instrument has two calibration factors used when estimating pipe occlusion gain and packing factor The following section gives details on how these factors are calculated This menu option gives the user the opportunity to modify the calibration factors The up and down keys are used to select the factors and the left and right keys increase and decrease the selected factor With gain or packing selected press enter to store the values and exit to the main menu To revert to the factory calibration press enter button with default selected Page www diverse technologies net Calibration and pipe occlusion A magnetite sample was used for calibration This was a cuvette 1cmx1cmx1 5cm packed with magnetite flakes A force measurement was recorded with the centre of a long side of the cuvette 5mm from the centre of the probe measurement surface to simulate a pipe wall thickness This value is taken for the factory calibration gain and the software assumes that this value corresponds to an occlusion of 75 in a tube of 40mm inner diameter and 5mm wall thickness By measuring the mass of the cuvette the density of the magnetite flake sample was calculated and compared to the density of solid magnetite This gave a packing factor of 48 This factor is used in the display of occlusion fo
4. lusion IMPORTANT This instrument uses magnetic force balancing and requires specific equipment to set the unit up for optimum operation It the instrument requires repair this can only be undertaken at Diverse Technologies If the MF500M requires repair the unit should be returned to Diverse there are no user serviceable parts Page 16 www diverse technologies net Disposal and Recycling This instrument should be deposed of in a responsible manner to allow the components within it to be recycled The wheelie bin symbol shown here and on the product means that the product is classed as Electrical and Electronic Equipment and should not be disposed with other household or commercial waste at the end of its working life The Waste of Electrical and Electronic Equipment WEEE directive 2002 96 EC has been put in place in the EU to recycle products using the best recovery and recycling techniques to minimise the impact on the environment treat any hazardous substances and avoid landfill Business users should ensure that this product is not mixed with other commercial waste for disposal Page 1
5. ng the whole of the inside surface of the pipe or just a sector as would happen with a horizontal pipe where either flakes of magnetite have accrued or the water has not fully filled the pipe From the analysis we have done if the ratio Smax Smin lt 1 5 then the accrual might be deemed to be evenly coated Measurement phase 2 even coating A graph attached is the reading from the instrument for a range of thickness and pipe sizes internal diameter so in order to estimate the coating thickness locate the reading on the y axis trace horizontally to the curve for the pipe size under test and then trace vertically down to the horizontal axis and read off the estimated thickness Measurement phase 2 sector coating Starting at the point where the signal is a maximum Smax with a chalk mark to indicate this position slowly move the probe round the pipe maintaining the probe at a tangent to the Page 12 www diverse technologies net Calculation of Magnetite from MF500M readings Mag thickness Radius pipe surface until the signal has fallen to Smax 2 Mark the pipe again Repeat the prodecure in the other direction In each case note the angle from the Smax position take the average of these as 0 the half angle Defining the sector thickness t to be the thickest point of a sector bounded by the inside of the pipe and a straight line across the arc and R is the radius of the inside of the pipe The estimate
6. of sector thickness tis t R 1 cos 0 1 Ratio of sector thickness to radius is q 1 cos 0 0 lt 8 lt 90 Occlusion f fraction For 0 in radians f 0 sin 20 4 7 For 8 in degrees f 0 7 180 sin 28 2 180 4 7 2 Expressions 1 and 2 are plotted below together with a simple linear approximation that could be appropriate for quick assessments Estimated Magnetite thickness Radius v half angle Estimated pipe Occlusion v half angle Fa RE ar mr Fl Fn i i Fe 80 100 Half angle deg Page 13 www diverse technologies net N MD MF500M Specification Reading range 0 to 1022 force units Occlusion 0 to 100 Technique Uses net magnetic force to identify magnetite and magnetic material Reading range 0 1022 force units These are arbitrary units and each instrument needs to be calibrated to the specific pipe geometry and Accuracy magnetite samples Can be zeroed at anytime measurement technique requires unit to be zeroed in the measurement orientation Probe orientation Measurement independent of probe orientation provided it is zeroed first in that orientation Gravity Zero removes gravity offset Display 4 lines of 16 characters Shows value and user interface messages Functions Raw force occlusion for solid and broken magnetite Internal data sample rate 500 samples per second Repeatability 5 assuming sample is degau
7. p menu select and at power on e double beep measurement recorded e triple beep unit powered off e long beep zero offset value updated Page 5 www diverse technologies net Operation Options Menus lt Measure gt This is the normal mode of operation There are two display modes for this menu which can be toggled using the up or down keys Data is updated approximately every second The first mode displays the measured value currently stored offset and signal difference on the bottom line The next available record number is shown on the top line The second display mode estimates the amount of pipe occlusion based on the current measured and offset values note there are a number of assumptions in these estimates see section on calibration Note that data displayed on the first of these display formats is what is recorded on a short probe button press lt View records gt Press enter to view stored records 4 records shown 1 record per line Enter toggles between two display formats Default format is record number measure value stored offset and signal difference between measured and zero offset Alternative format gives record number and signal Use up and down buttons to scroll through stored records Continuous press of up or down scrolls records Left and right buttons leave view record menu Page 6 www diverse technologies net Operation Options lt Clear records gt Press
8. r solid magnetite Calibration settings can be altered using the lt Calibrate gt menu User offset adjustment The offset has been set to be nominally 50 counts with the probe held horizontally In the unlikely event that the offset needs to be adjusted then this can be carried by adjusting the potentiometer Gently peel back the calibration label to access the potentiometer using a small screwdriver clockwise will take the offset positive anticlockwise will take the offset negative Replace the calibration label after adjustment Note that the meter s range is nominally 0 to 1022 force units Page 8 www diverse technologies net Measurement technique The meter provides a number that increases with the amount of magnetite present The following aspects should be noted 1 The meter is sensitive to gravity so it is important that the meter is zeroed away from the pipe in the same orientation as the measurement to follow 2 The meter is designed to work with a space between the probe cap and magnetite If the meter is too close to magnetite or indeed a ferritic sample then a raw reading of 1022 will be displayed 3 Magnetite distribution will effect the measured value i e a small amount of material close to the probe will give the same signal as a larger amount further away Magnetite tends to accumulate on the corners of cooling pipes where the pipes turn from vertical to horizontal At these points the
9. robe orientation in respect to gravity forces Clearly the magnetite could be in any amount at any point in the pipe but in reality there are only really 2 likely scenarios Firstly the pipe is fully filled and in normal use there is continuously flowing water filling the tube In this case the magnetite is likely to be evenly deposited on the inside surface Note this is not guaranteed and could be affected by turbulent flow or surface finish attributes The second scenario is that the magnetite has accumulated on one side of the pipe This can be due toa horizontal pipe that is not fully filled or accumulation of flakes of magnetite building up under gravity The measurement rote attempts to identify which type of deposit is in place and then estimate the deposit thickness from the measurement Before starting the probe should be placed in a position at least 1m from any magnetic material instrument should be zeroed This removes any constant offset in the measurement system to be removed from all subsequent measurements Page 11 www diverse technologies net Calculation of Magnetite from MF500M readings Measurement phase 1 Placing the probe on any point on the surface of the pipe Slowly move the probe around the surface of the pipe keeping the face of the probe at a tangent to the pipe surface noting the points where the reading is the highest and lowest Smax and Simin Now we have to decide whether the magnetite is coati
10. ssed Probe size 20mm x25mm 150mm long Detection Detects the magnetic force between the sensing magnet and the magnetite The signal is offset by an estimate of the gravitational force Storage Maximum of 20 records can be stored Probe cable length 1 5m typical Calibration Calibration is indicative only Unit is supplied with a calibration sample of magnetite so that the instrument functionality can be verified Power 4 standard AA cells typical lifetime 12 months Continuous use 30 hours Page 14 www diverse technologies net Liability Diverse Technologies accepts no responsibility for the consequential losses arising from the ability or inability to use the equipment supplied The limit of warranty is the repair or replacement of any faulty components directly attributable to manufacturing defects arising during the period of 12 months following purchase This does not include damage resulting from incorrect operation of the instrument Designed and manufactured by Diverse Technologies amp Systems Ltd Zeromag House 46 48 Whittlesford Road Shelford Cambridge CB22 5EW UK Tel 44 0 1223 84 44 44 Email sales diverse technologies net http www diverse technologies net Page 15 www diverse technologies net Calibration and repair The MF500M and probe is not supplied with a calibration certificate It s operation is indicative only to be used to determine the potential level of pipe occ
11. www diverse technologies net DIVERSE MAGME TER MF500M MAGNETITE METER USER MANUAL DIVERSE CAMBRIDGE ENGLAND CB22 5EW www diverse technologies net Page 1 www diverse technologies net Contents INTRODUCTION FIRST TIME QUICK START OPERATION OPERATION OPTIONS CALIBRATION AND PIPE OCCLUSION MEASUREMENT TECHNIQUE SPECIFICATION LIABILITY CALIBRATION AND REPAIR DISPOSAL AND RECYCLING Page 2 www diverse technologies net Introduction Thank you for purchasing MF500M Before using the unit please read these instructions carefully If you are uncertain about any aspect of its operation please contact Diverse our contact details are at the end of this manual The MF500M is designed to measure magnetite in non magnetic stainless steel pipes particularly cooling pipes in power stations The MF500M Magnetic Field Meter uses a force technique to detect and quantify levels of magnetic material particularly magnetite contained within stainless steel pipes Because of this itis IMPORTANT that the pipe walls are not magnetic Page 3 www diverse technologies net First time quick start The unit requires 4 AA cells which should be installed in the battery compartment on the rear of the housing Measurements are made by bringing the metallic front of the probe into contact with the outside of the pipe The probe is sensitive to gravity and should be zeroed in the same orientation as the m
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