CONTINUOUS FRICTION TESTER - CFT Trailer Mounted System YAWED WHEEL Technical Specification Unit 2 Iceni Court, Icknield way Letchworth Hertfordshire SG6 1TN England Tel: + 44 (0) 1462 681 699 Email : info@pavetesting.com Web: www.pavetesting.com March 2012 Page 1 of 16
TABLE OF CONTENTS 1 PAVETESTING... 3 1.1 Background... 3 2 CFT SPECIFICATION... 5 3 SYSTEM... 7 3.1 General... 7 3.2 Water Delivery System (Optional)... 8 3.3 Trailer... 9 3.4 Electronics... 11 3.5 Laptop Computer System... 11 3.6 Load Cell... 11 3.7 Distance Sensor... 11 3.8 Ambient Temperature Sensor... 12 3.9 Ground Temperature Sensor... 12 3.10 Main Electronic Control... 12 4 CFT SOFTWARE... 13 4.1 Software... 13 4.1.1 Main Screen... 13 4.1.2 PROGRAM Screen... 14 4.1.3 PROGRAM... 14 4.1.4 Run Screen... 14 4.1.5 Export File... 15 5 GENERAL PHOTOS... 16 Page 2 of 16
1 PAVETESTING 1.1 BACKGROUND PaveTesting Ltd, has been producing high quality engineering equipment within the United Kingdom for over 10 years. It has built up a reputation of outstanding support and customer satisfaction with its strong technical support team an innovative design engineers. PaveTesting Ltd has grown by continually developing new products and services to meet customer demands and international standards. Its range of friction, deflection and profile measuring machines are considered to be the best in the industry. This system manual has been written to give a trained operator the ability to reference items that were explained in detail during the training session that each customer receives upon delivery of a new machine. If you have not been trained on the operation of this equipment please contact PaveTesting Ltd before proceeding to operate the Falling Weight Deflectometer. The Side Force Continuous Friction Tester hereafter called the CFT, has been designed and built to be robust, consistent and reliable in all environmental conditions to measure the coefficient of friction of a pavement surface as required by Highways and Airports. Deterioration of the surface friction can be from the polishing action of the vehicle tyre rolling and braking on the pavement or from the introduction of contamination, namely water, snow, slush, ice or rubber on the surface. The CFT is capable of measuring and recording the surface frictional properties in accordance with Federal Aviation Administration (FAA), International Civil Aviation Organization (ICAO) and the Civil Aviation Authority (CAA) requirements. The CFT is fitted as standard with an ambient temperature sensor and non contact ground temperature sensor, an automatic wheel up system and a water flow rate monitoring system as optional. The CFT is designed to measure the side force coefficient of friction which has been harmonized with the SCRIM friction tester. The device is mounted to a suitable 3 wheeled trailer that is towed at speed by the towing vehicle fitted with a suitable towing attachment. Optional wetting systems configurations include manual adjustment of water flow rates or automatic adjustment of water flow rates to maintain consistent water depths independent of testing speed. Page 3 of 16
Water tank sizes vary from 250 to 1000 liters depending on the vehicle specification. The data from the main electronics is sent to the dashboard mounted computer system giving real time graphical representation of Friction / Speed and distance. Software is provided and installed to the customer supplied computer system. Multiple computer platforms can be employed. Page 4 of 16
2 CFT SPECIFICATION Trailer DIMENSIONS: Length : Width : Height : 1553mm 960mm 570mm Towing Hitch Height Operational Weight Including ballast but excluding jockey wheel 350 ±12 mm 254 kg Weight distribution with jockey wheel fitted At Port wheel at calibration height At Starboard wheel - at calibration height At Rear wheel 77.5 ±l kg 77.5 ±l kg 53.5 kg nominal Tyres Friction Measuring Tyres (Special slicks) Distance measuring wheel ASTM E1551 4.8x8x4 6 ply Tyre Pressures Friction Measuring Tyres Distance Measuring Wheel 0.7 ±0.035 kg/sq cm 2.1 ±0.137 kg/sq cm Towing Speed Normal Friction Testing 48 kph to 96 kph may be operated at 128 kph Page 5 of 16
Operating Climatic Conditions Temperature - Vehicle mounted components 0C to +50C (15 minute warm up time required at lower temperatures) Temperature - Trailer mounted components -30 to +60C Humidity 95% at 15 C Friction Measuring Accuracy Average friction value ±0.01 maintained for any instance not less than 50 meters between computations. Distance Measuring Accuracy ±0.1% plus tyre wear Operating Voltage Vehicle supply 24V DC Max 8amp reproduced without prior written permission of PaveTesting Ltd Page 6 of 16
3 SYSTEM 3.1 GENERAL The CFT Side Force Machine is a surface friction measuring and reporting system for testing paved surfaces at speed. The equipment consists of a ballasted three-wheeled trailer as shown below (Tow Vehicle not supplied). Incorporating electronic measuring systems which operates in conjunction with a computer carried in the chosen towing vehicle. The trailer system produces signals which are sent to the laptop computer via a secure 100mps Ethernet connection, and processed for later down loading to an office printer. In addition, the recorded data can be exported via the laptops USB port. This feature provides the ability to down load the data to a compatible computer for data storage and analysis at a later time. Page 7 of 16
3.2 WATER DELIVERY SYSTEM (OPTIONAL) A water delivery system is available as 'Customer Extra' and can be supplied to supplement the CFT when it is required in dry weather. For more information on the various designs of Water Delivery System please contact PAVETESTING for more information. Below is a typical Installation of an Automatic Water Delivery System installed in to a FORD F150 Pickup Truck. Water Tank Electric variable valve Control Electronics Electric Pump Digital Flow Meter Piped to the CFT In addition to the water delivery system a laminated nozzle system is installed on to the CFT. Below is a photo showing the nozzle and the nozzle assembly installed on to the CFT. Page 8 of 16
3.3 TRAILER The fabricated steel chassis consists principally of two main side members, the front fixing bracket and top frame. The fixing bracket accommodates an adjustable height ball hitch which can be varied to suit the available tow vehicle. The caster wheel bolted to the front fixing bracket is used to support the CFT whenever it is disconnected from the towing vehicle and stationary. Below is a photo of the CFT with the Main Top Cover Removed and the Wheel Ballast Weights removed. Two heavyweight, steel wheel guards are assembled on studs to the top frame, each with are ballasted at final assembly to give the correct wheel weights. Below is a photo of one empty ballast weight. Page 9 of 16
Two telescopic, damped shock-absorbers are interposed between the chassis side members and top frame to accommodate road/runway shock-loads. The single spring,, acting between the top frame and rear wheel arm, retains the rear wheel in constant contact with the surface and stabilizes the trailer during measuring operations. Below is a photo of the underneath of the CFT, showing the 3 Spring Shock Absorbers. All three wheels have tubed pneumatic tyres and run on taper roller bearings. The side wheels, used for friction measuring, have smooth tyres and are mounted on stub axles. The axle is pined and secured with a hydraulic system so the angle can be adjusted from Zero to 7.5 degrees tow out. For friction testing the two friction tyres give an inclusive angle of 15 degrees to the direction of travel. This induces a side force which is recorded by the load measuring device. When not measuring the tyres are set to Zero degrees. This eliminates tyre wear. The rear wheel, used simultaneously for measuring distance travelled and stabilizing the trailer, has a treaded tyre and is stub axle mounted on the end of a fabricated steel arm. The arm is attached at its front end to the chassis right side member by a stud shaft, enabling it to Pivot. Page 10 of 16
3.4 ELECTRONICS Information sensing, conditioning, processing, recording, storing and visual display are all performed by the electronic system. It is contained in discrete items; these are; the load cell, distance sensor, temperature sensors and the signal conditioner which are all mounted on the trailer. A laptop computer is used for display and data recording which is mounted in the towing vehicle. Electrical connections between the units are made through conventional electrical interface connectors giving protection from the ingress of moisture to IP68 standards (water proof). 3.5 LAPTOP COMPUTER SYSTEM The processing power required to perform the in vehicle display and storage is minimal compared to modern computers of today. Therefore the Laptop computer system can be of any modern design or functions to meet the customer s needs. Please contact PAVETESTING for more information on suitable computers. 3.6 LOAD CELL The load cell fitted to the CFT is designed to measure tensile side force as generated by the surface friction. Spherical bearing eye-ends eliminate any induced loads through which it is pinned to the two chassis swing arms. 3.7 DISTANCE SENSOR The distance sensor is an inductive sensor measuring 10 pulses per revolution of the distance measuring tyre, giving an accuracy of speed to 1%. Below is a photo of the DMI and the 10 hole disk. The DMI is fitted with a LED to display correct function. Page 11 of 16
3.8 AMBIENT TEMPERATURE SENSOR An ambient temperature sensor is installed next to the load cell. Temperature readings are taken and displayed within the software during the test and outputted to the excel data file. 3.9 GROUND TEMPERATURE SENSOR A non contact ground temperature sensor is installed next to the load cell. Temperature readings are taken and displayed within the software during the test and outputted to the excel data file. 3.10 MAIN ELECTRONIC CONTROL The signal conditioner is mounted on the top frame and enclosed within an aluminium IP68 enclosure (Water Proof). The information from the sensors are converted to digital and conditioned to give actual distance and friction readings respectively. This reduces the workload on the laptop processor. Page 12 of 16
4 CFT SOFTWARE 4.1 SOFTWARE The CFT software has been purpose written for ease of use and touch screen technology with Multilanguage Support. The software can run on most Microsoft Windows XP and Vista computer systems. Contact PaveTesting Ltd for the latest computer specifications. 4.1.1 MAIN SCREEN This is the main start up and menu screen. From here all other areas of the software can be selected. Page 13 of 16
4.1.2 PROGRAM SCREEN From the main menu screen if the OPEN button is pressed, this will open the Program Screen. The program screen is divided in to two styles of testing. ROAD or RUNWAY. 4.1.3 PROGRAM 4.1.4 RUN SCREEN Page 14 of 16
4.1.5 EXPORT FILE Every Friction test performed is saved within the Laptop computer. The Default folder is c:/cft Program (this can be changed within the SET UP section of the software) It is advised that all data collected with the CFT is stored on a remote computer for archive and safety. The data can be easily exported to a memory key or across a standard office network system using standard Microsoft Windows tools. If more advice is required on how to save and store the data please contact PaveTesting Ltd. Each Friction Test is given a unique from the Program Number with the followed by the date and time of the Run. The format of the Output file is a.csv file format. This format can be opened with many data based software programs such as Microsoft Excel. The resolution of the output file is determined by the value entered in the System Setting section Auto Compute Distance. Optional GPS data can also be included in the data file. Contact PaveTesting for more information. Page 15 of 16
5 GENERAL PHOTOS Page 16 of 16