Loadcell’s main parameter 1. rail’s specification (confirm the mounting size to loadcells) The rail’s height, the width of railhead, rail flange or rail’s model number (such as QU80) 2. loadcell’s applications: Coal-tax weighing, steel mill’s measurement, detection device of railway’s overload, static weighing, dynamic weighing, etc 3.loadcell’s mounting way Platform type, cushion-rail type, rail-breakage type and squeezing type
Rail Weighbridge Loadcell’s Mounting Way 1. Platform type 2. Cushion-rail type 3. Squeezing type 4. rail-breakage type 5. Strain gauge –paste- rail type 6. Static portable type
1 platform type Column Type loadcells (ZSNC/ZSKB/ZSF) are usually used in platform type rail weighbridge, pay attention to sensitivity, capacities, corner difference, weighing platform’s limit
Attention points for platform type rail weighbridge • 。Weighing platform requires high strength, preventing the output error from platfrom’s deformation • The 4 corners under weighing platform are with height-adjusting structure, to make sure that each loadcell will undertake force averagely • The weighing platform's panel is movable, will adjust loadcell’s centrality. • Loadcell’s stress ball socket should be large enough, to make sure the installation will be in right place. • Loadcell’s sensitivity should be controlled within 0.03%.
2、Cushion Rail Type Loadcell Used in continuous rail, vehicle speed ≤20km/h when dynamic weighing. Cushion rail type loadcells are widely used in railway, with features of high accuracy, stable performance and strong loading ability, convenient installation and short cycle construction. Using way: usually 16 pc as one group, and each side install 8 pc, picking up the whole rails in two sides, then the weighing platform is made. Before laying rail, steel plates should be buried under loadcells, which shall be replaced by the steel plate after finishing foundation construction. Loadcells are matched with junction boxed to avoid the damage from surge voltage and current loop.
3. Squeezing type Loadcell 2 loadcells are one group, directly installed in bore-holes A,B of rail web, when vehicle wheels stopped in the area between A and B, loadcells will produce voltage signal from the ratio between loadcells and wheels' weight. After collecting the signal, wheels' weight can be got. While when wheels stopped out the AB area, effective signal can’t be output from loadcells. Force analysis: when vehicles run from crosstie ZA to ZB, shear force QA,QB will change as following picture, we will find that when wheels run from ZA to A or ZB to A, QA=QB, while when wheels run from A to B, QA and QB are with opposite direction. Therefore, when wheel is out of area AB, minus QB from QA, the different value is zero. While when wheel is within area AB, its different value equal to P
small diameters squeezing type XZFLC-SS20t • Loadcell’s diameter is smaller, convenient for mounting • With quincunx shape, guarantee the force value will be delivered efficiently • Rail web’s taper hole requires less processing work, making sure its safety.
Overload and unbalanced detector on rail • By combination of cushion type loadcell and squeezing type loadcell, unifying fixed rigid support and loadcell strain technology, through data collective controlling system, transmitting output waveform to computer for analyzing, the weight of moving train, speed and overload/unbalanced message will be counted. The theory is together wheel’s shear force and gravity, and take average value after correction.
4. Rail-breakage Loadcell • Usually, rail-breakage type weighbridge will come with approach rail, which will relieve the influence from the running vehicle’s shaking, it with high accuracy, can be used in different areas in static or dynamic state. • Using way: after strengthen the bases, cutting out the same size gap from the rail, and loadcells are installed in the gap, please be sure that the space in 2 sides of loadcell will be in the range of 0.5-2mm. Weighing will output rectangle waveform, it is easy to collect and manage the dynamic weighing data.
Common Loadcells of rail-breakage type GGF GG GGB QSP
5.Strain-gauge-pasted-on-rail Loadcell • Taking standard steel rail as elastomer, pasting strain gauge on plate of standard rail, to composing the Wheatstone Bridge, to make the loadcells
Attention points for Strain-gauge-pasted-on-rail Loadcell • Strain-gauge-pasted-on-rail loadcell is connected with approach rail by fishplate; • Strain-gauge-pasted-on-rail loadcell should be in free state, rail gap can’t be to tight or too large, and measures of anti-crawling should carried out. • The distance between cement pillows should be within 600±10 mm . When Mounting, the 2 sides of loadcells should be symmetrical. • Adopting moisture proof design, anti-interference design, earthing and shielding design, to improve the accuracy of weighing.