V. Tsymbalyuk, J. Linhart
CORRECTIONS OF AERODYNAMIC LOADINGS MEASUREMENT ON AIRFOIL CASCADE AT BENDING-TORSION VIBRATIONS

The paper describes improvement of the unsteady aerodynamic forces and moments measurements in an airfoil cascade. These loads are caused by shifting and angular vibrations of airfoils. The improvement was achieved by taking airfoils and other elements deformations, induced by action of innercia and measured aerodynamic firces, in consideration during the calibration and measurement process. The different variants of airfoils supporting are considered.

Sinan Fank
INFLUENCE OF MICROSTRUCTURAL CHANGE IN AISI 4340 STEEL SPRING MATERIAL HAVING IDENTICAL HARDNESS LEVEL ON THE HYSTERESIS ERROR OF FORCE TRANSDUCER

Different heat treatment processes can be applied on the spring element of a force transducer in order to obtain good and satisfactory performance. The manufacturers are generally focused on the improvement of performance by applying different heat treatments on spring material, and no information is in free circulation regarding the process-performance relationships of transducers due to tight competition in the market. The study covers the attempts of different heat treatments on spring element using AISI 4340, which is regarded as one of the best spring materials for force transducer applications. The steel was quenched and tempered at predetermined temperature, and 45 Rockwell-C hardness values was reached to obtain fine martensite structure. In order to obtain coarse martensite structure having identical hardness from spring material, some specimens were subjected to high temperature during austenite transformation in 1000°C in 4.5 hours priority. In order to produce bainitic structure different heat treatment was applied on the specimens to have identical hardness level. It was observed that different heat treatments influenced the transducer performance, particularly hysteresis behaviour point of view. To minimize the hysteresis error of force transducers has prime concern and best result was obtained in the bainitic- structured specimen. After building the force transducers with differently heat-treated spring materials, their performances were recorded by using a dead weight force standard machine, concentrating on hysteresis characteristics. The results were compared with each other and analysed regarding the structural properties of spring materials and a process path was proposed to obtain the best performance in force transducers.

Levent Yagmur, Sevda Kacmaz
ENDURANCE TESTING MACHINE FOR NONAUTOMATIC WEIGHING INSTRUMENTS

A machine was designed and manufactured for endurance tests of nonautomatic weighing instruments according to the regulation of OIML R76-1-2 and EEC/90/384. An AC servomotor directly actuates the machine. It has also control panel and software. It has a compact module consisting of ball screw mechanism and a handler, made of polyamide material, specially designed. It is used for handling nine numbers of standard masses, knops headed type, with ranges 100 g up to 50 kg. There are nine types of weight carriers for each different mass. Some parameters for loading and unloading of masses can be set to desired values within limits by using control panel. The velocities of loading and unloading of masses and also standing time of mass on the instrument can be adjusted. All parts of movable section of the machine were enclosed by using plexiglas material for preventing. The machine is capable of 100.000 and more times fully automatically loading and unloading of 9 (nine) types of standard masses on to the instrument. It can also be modified to another standard masses not in range 100 g to 50 kg.

Ryosuke Tasaki, Takanori Yamazaki, Hideo Ohnishi, Masaaki Kobayashi, Shigeru Kurosu
CONTINUOUS WEIGHING ON A CONVEYOR BELT WITH FIR FILTER

Today much higher speed of operation and highly accurate weighing of packages during crossing a conveyor belt has been getting more and more important in the food and distribution industries etc. Continuous weighing means that masses of discrete packages on a conveyor belt are automatically determined in sequence. Making the best use of new weighing scale called a multi-stage conveyor belt scale which can be created so as to adjust the conveyor belt length to the product length, we propose a simplified and effective mass estimation algorithm under practical vibration modes. Conveyor belt scales usually have maximum capacities of less than 80 kg and 140 cm, and achieve measuring rates of 150 packages per minute and more. The output signals from the conveyor belt scales are always contaminated with noises due to vibrations of the conveyor belt and the product in motion. In this paper an employed digital filter is of Finite-duration Impulse Response (FIR) type designed under the consideration on the dynamics of conveyor belt scales. The experimental results on conveyor belt scales suggest that the filtering algorithm proposed here is effective enough to practical applications.

Michael D Collins, Neculai Moisoi
A New Tool to Improve Fiscal Monitoring and Custody Transfer in The Oil and Gas Industry

Typically, differential pressure transmitters used for fiscal monitoring and custody transfer purposes are often calibrated with the low side open to atmosphere. If the relevant line pressure is not applied during the calibration of differential pressure transmitters, the validity of the calibration is questionable. It is widely acknowledged that the output of differential pressure transmitters changes with line pressure due to mechanical distortion of the wetted parts. Although the distortion is thought to be extremely small, the high degree of sensitivity results in a significant change of output. The main reason these devices are not calibrated at line pressures is the high cost and complexity of existing calibration standards, usually twin post piston gauges and pressure dividers. This paper gives an overview of the early development of a new differential pressure standard, more stable and accurate than the classical twin post balances. This new differential pressure standard is easy to use and the time required to perform the measurements is considerably reduced compared with the more established traditional methods. The line pressure range is 0 to 30 MPa with a differential pressure range of 0.1 to 700 kPa. The piston gauge will be described in detail including its metrological characteristics and ease of operation.