S K Jain, S S K Titus, Falk Tegtmeier, Norbert Tetzlaff, Daniel Schwind
LOW UNCERTAINTY IN FORCE VALUES ACHIEVED IN A LEVER MULTIPLICATION DEADWEIGHT FORCE STANDARD MACHINE OF 1 MN

Keeping in mind the need to have lower measurement uncertainties associated with force standard machines (FSM) to calibrate force instruments, the National Physical Laboratory of India (NPL(I)) has recently installed a new 1 MN force standard machine. The force is generated by dead weights up to 100 kN and a lever multiplication of dead weights up to 1000 kN. The machine has certain novel design features, which result in the lowest uncertainties. This paper contains a description of the functional principles and new design aspects of this machine. The uncertainties of measurements are calculated for both the lever and the deadweight side according to the new EURAMET calibration guide. The results of a comparison with the Physikalisch-Technische Bundesanstalt (PTB) are presented here, too.

Christian Buchner, Zoltan Zelenka, Thomas Mikats, Friedrich Bleicher
DETERMINATION OF FORCES FROM 10 N UP TO 250 kN USING TWO FULL AUTOMATICAL DEAD WEIGHT MACHINES DEVELOPED BY THE BEV

The Austrian national metrology institute, the Federal Office of Metrology and Surveying (BEV) developed and realised in 2008 an automatic dead weight machine to determine small forces in the range of 1 µN - 10 N with a special construction that allows to measure continuously from 10 N tensions to 10 N compressions. It makes possible to cover the complete range without changing the mounting of the force transducer under calibration.
After the successful establishment of this equipment, the BEV started in 2010 together with the Institute of Production Engineering (IFT) of the Vienna University of Technology to realise another dead weight force machine in the range of 5 N - 2 kN based on the same technique. This machine also allows to measure continuously in 10 N steps over the whole range from tension to compression without changing the mounting of the force transducer.
To cover the higher range of force in addition to the previously described ones, a dead weight standard machine based on the conventional technique (separated measurements for tension and for compression) in the range of 50 N - 250 kN was built. This machine is also capable using a hydraulic amplification to cover the range of 1 MN and 5 MN.
All dead weight machines allow controlling each and every weight separately. They have special designed beam balance constructions to compensate the weight of the suspension system. Due to the precise determination of the position of the balance beams using laser, the systems are able to compensate the deformation of the force transducer under stress. The usage of this compensation is drastically improving the reproducibility of the systems.
A further advantage of these machines is that their constructions enable the periodic recalibration of the weights without changing the adjustment of the dead weight machine.
All the systems were finished at the end of the year 2011. According the schedule first internal and then bilateral international comparisons will be carried out from summer of 2012 to validate the performance of the machines.

Lee Shih Mean, Hoh Wing Yew, Lim Lee Kwee
A VERSATILE WEIGHING SYSTEM FOR STANDARD WEIGHTS MEASUREMENT USING MANUAL PLATFORM BALANCES

Platform-type manual mass comparators are commonly used for the calibration of high precision heavy mass standards. While some automated heavy mass calibration systems are available commercially, they are very expensive and are not economically viable for most laboratories offering calibration services.
NMC, A*STAR has developed a low-cost, automatable, weights handling system for use with commercially available platform type mass comparators. This system is designed to be versatile and adaptable for easy loading and unloading of reference and test mass during calibrations.
With this system, it is possible to achieve a marked improvement in repeatability measurement by as much as three times as compared with manual weighing using the same comparator. The system reduces the wear and tear of the mass standards and drastically reduces the risk of injury to calibration personnel due to lifting of heavy masses.

Yao Jinhui, Li Qingzhong, Xu Hang, Li Haigen
A NEW VERIFICATION SYSTEM OF MOBILE SCALES

The paper describes a new method to verify the fixed electronic scales or called mobile scales being weighing range of 50 - 150 t. It consists of 4 parts: standard weights of class M1, a 150 t mass comparator (MC), a set of moveable build-up force standard machines( MBM) and mobile scale (MS) to be verified, which is called 4M verification system(4MS). The paper describes principle, construction and specifications of MBM. It has been done to make comparison of the two verification methods by M1 weights and MBM, of which the verification results are quite agreeable.

Zoltan Zelenka
NEW PRIMARY BALANCE OF BEV FOR HIGH-PRECISION MASS DETERMINATION AND REALIZATION OF THE MASS SCALE IN THE RANGE FROM 10 G UP TO 1 KG

The Austrian Federal Office of Metrology and Surveying (BEV) has developed and realized in cooperation with Sartorius AG (Göttingen) and the Vienna University of Technology a new 1 kg high-precision mass comparator. The new balance is intended to be used for automatic calibration of weights with high precision, for the realization of the mass scale in the range from 10 g up to 1 kg and for mass calibration of density standards.