Installation Guide for ultrasonic transducers

Transcription

1 Installation Guide for ultrasonic transducers 1

2 1. Welcome at systec Thank you very much for using deltawave. This document provides you with all necessary information to install the transducers accurately in open and closed channels. 2. Content 1. Welcome at systec Content Measurement Accuracies and suitable locations Ultrasonic Transducers for direct wall mounting Acoustic path Finding the right installation positions for the transducers Wiring Using Transducers for Ex Zone 1 and Ex Zone Solar irradiation / Icing Further Information Need help? Installation Protocol Annex Positions for mounting of transducers in case of filled conduit

3 3. Measurement Accuracies and suitable s locations The accuracies strongly depend on the Inlet conditions. Please see the tables below for expected accuracies. Application open channels or partially filled pipes Straight inlet Number of Paths Accuracy* >10D 2 3-4% >10D 4 2-3% >10D 6 1-2% <5D 2 x 2 (crossed) 3-4% <5D 4 x 2 (crossed) 2-3% <5D 6 x 2 (crossed) 1-2% Application filled pipes or filled rectangular channels Straight inlet Number of Paths Accuracy* >10D 2 1,5-2% >10D 4 0,5-1% >10D 6 0,5% <5D 2 x 2 (crossed) 1,5-2% <5D 4 x 2 (crossed) 0,5-1% <5D 6 x 2 (crossed) 0,5% Table 1 Accuracies * Accuracies are stated as percentage of flow for all velocities over 0,1m/s. Below 0,1m/s the accuracy is stated as percentage of 0,1m/s 3

4 4. Ultrasonic Transducers for direct wall mounting Cable Transducer Mounting Plate (PVC) Clamp Membrane Slot for wall mounting Protection Picture 1 Ultrasonic Transducer with mounting plate 4

5 There are different solutions to mount the transducers. The shown mounting plate is used for direct wall mounting as a standard. Dimensions HT Type 1 MHZ H=35mm L=130mm B=70mm X=49mm HT =25mm X Type 500kHz H=50mm L=175mm B=90mm X=70mm HT= 35mm Picture 2 Ultrasonic Transducers, Dimensions for Standard Mounting Plate 5

6 5. Acoustic path L Picture 3 Scheme of an acoustic path The direct connection line (red line in the picture) between two ultrasonic transducers is called an acoustic path. The alignment of two transducers to each other and the correct value of the path Length L and the flow angle α is very important for accurate measurement. As a standard the transducers are designed for a flow angel of 45 (others available on request) Please make sure that the transducers are installed at the right position. The angle and the path length have to be measured accurately after finishing the installation. The transducers have to aligned properly ( must see each other ) to allow good signal transmission. 6. Finding the right installation positions for the transducers Picture 4 Mounting of transducers draw vertical line Please choose a suitable location for installing the transducers (see chapter 3) Please draw a vertical line (right angle to channel bottom) on one channel wall as shown in picture 1. 6

7 Second vertical subsidiary line Picture 5 Mounting of transducers draw second vertical line Now you can mount the transducers along that line. For the installation levels (Picture 3: h1..h4): Please make sure that at least 2 transducers are covered with water even in case of minimum level. Please make sure that all paths are covered with water in case of typical level. Please make sure that the distance between the transducers (and to the channel bottom for the first transducer) is due to the recommendations of the ISO6416 (see Table 3). For filled channels please follow the guidelines from the IEC41 standard. This standard provides clear mounting positions for your transducers (see chapter 13) which shall be used. Width of channel Minimal surcharge and minimal distance from bottom < 1m 0.04m 3m 0.07m 5m 0.1m 10m 0.15m >30m 0.21m Table 2 Installation levels of the transducers Please draw a second vertical subsidiary line at the opposite wall (right angle to channel wall) as shown in Picture 5. You can use a rotating laser to ensure the 90 angles. h4 h1 h2 h3 a Picture 6 Finding the mounting positions for the opposite transducers 7

8 Please draw another vertical line (right angle to channel bottom) in the distance a to the previous line as shown in Picture 6. This is the right position for installing the opposite transducers. See the next picture how to calculate the accurate distance a. a α B c Picture 7 Calculate the distance a B= Channel Broadness, α = flow angle, c = distance from channel wall to the middle of the transducer (when using standard mounting plate as shown in Picture 1, c = HT (see Picture 2)) a = needed distance Please use the formula a = (b-2c) / tanα to calculate the needed distance a. h3 h4 h2 a h1 Picture 8 Mounting of the opposite transducers 8

9 Now you can install the opposite transducers. Please make sure that the two corresponding transducers are mounted at the same level (levels h1..h4 must be the same as the levels h1 h4 in picture 3). 7. Wiring Please lay the cables in proper cable channels. The cables have to be protected against mechanical hazardous and (if necessary) against rodents. Please do not lay the cables together with supplying cables. This may have an influence to the signals. Cable type: RG58 A/U Triaxial Connection: blue = minus red = plus Please make sure that all cables are marked clearly and could be assigned to a certain trans- ducer! Please see the deltawave manual to see how to connect the cables to the electronic unit. 8. Using Transducers for Ex Zone 1 and Ex Zone 2 Certified Transducers are available for Ex Zone 1 (Type XUW-PC5 ) and Ex Zone 2 (Type UW05 EX1). Please see deltawave user manual for further information (separate document). Please note the following instructions for mounting: There should be no explosive atmosphere occur during mounting and demounting services and: o Only transducers with proper Ex name plates shall be used for applications in Ex (For different Designations see deltawave user manual) o The allowed operational parameters shall not be exceeded at any time o The transducers shall not be damaged. Damaged transducers shall not be used and operated in Ex environment. Damaged transducers loose the Ex certification. 9

10 9. Solar irradiation / Icing The ultrasonic transducers are suitable for working temperatures up to 60 C. The customer has to provide suitable shading if higher temperatures can occure due to solar irradiation. The ultrasonic transducers are suitable for working temperatures down to -25 C (if they are above the water level). Icing has to be avoided if the transducers are wetted. Icing could destroy the transducers! 10. Further Information Please see deltawave manual for further informations 11. Need help? Please contact your local systec agent for further information. Please visit our webpage to find your local agent. You can also call the systec headquaters for further informations: systec Controls Hotline: +49-(0) Installation Protocol Please use this installation protocol to ensure that all necessary date is obtained. Please make sure that all cables are marked clearly and can be assigned clearly to a certain transducer 10

11 Sketch of the Measurement Site: Protocol Path number 1 Installation level h distance a (see picture 3) Channel broadness b Flow angle α transducer height c Path length L Table 3 Installation Protocol 11

12 13. Annex 13.1 Positions for mounting of transducers in case of filled conduit When you have a filled conduit transducers should mount according to the IEC41 code. This code provides clear guideline where to mount your transducers. Picture 9 shows the required dimensions. They are equal also when having a rectangular-shaped channel. The required dimensions can be taken from Table 4. The Gauss-Legendre method is preferred for rectangular-shaped channels, the Gauss-Jacobi method is preferred for circular sections. Picture 9 Mounting positions for filled conduits acc. to IEC41 (1) When using different number of acoustic paths please contact your systec dealer for dimensions acc. to IEC41. 12

13 Table 4 Mounting positions for filled conduits acc. to IEC41 (1) 13