Tac Method to Overcome the Practical Difficulty in the Calibration of DWT With Insensitive Piston

Abstract

The cross float (CF) method is well-known for its accurate and reliable results, however the difficulty on performing CF method arises when dealing with insensitive piston of calibrated DWT. In contrary, automatic transducer assisted cross float (TAC) method could be implemented since it does not affected by this condition as it advantages. The used of TAC method could avoid up to 0.008% relative error of effective area at zero pressure and at 20 °C (A0,20) and twice higher error distortion coefficient (b) in case of calibrating insensitive piston of DWT. In addition, the TAC method has another advantage that is save time with consistent result because it can be performed automatically. Once should be consider when using TAC method is the accuracy of pressure transducer. In this case study, the existing pressure transducer owned by National Measurement Standard-National Standardization Agency (SNSU-BSN), could be utilized to perform automatic TAC method in lower pressure range down to 2 MPa that below 10% of its maximum scale, to calibrate low accuracy DWT greater than 0.08%.

The Measurement Method of a Piston Fall Rate

“…Usually, they demand certain technical conditions for proper measurement, and need to fit ideally for various design solutions among piston gauges. Moreover, their use is inconvenient in many cases during practical application since moving the sensor along with applying subsequent weights is required [9].…”

“…Fall rate characteristic indicates range [3] and construction of piston-cylinder assembly, and is used to verify the results obtained from calculations using analytical mathematical methods [5]. This parameter is inseparably correlated with the flow of the medium transmitting pressure in the gap between the piston and the cylinder of the measu-ring assembly [9,10]. Proper determination of piston fall rate makes cross-float calibration more precise and repeatable but is also crucial for determining effective cross-sectional area using other methods [7,8].…”

Metode Tac Semi-Otomatis Sederhana Untuk Memandu Kalibrasi DWT Pnumatik

“…Akan tetapi, metode ini membutuhkan transducer yang akurat untuk memperoleh hasil sebaik metode crossfloat. Transducer pada metode ini, digunakan sebagai pressure indicator untuk membaca tekanan dari kedua DWT secara bergantian sehingga dapat diketahui perbedaan tekanannya (Olson & Driver, 2013 (Ega & Samodro, 2014).…”

“…Keunggulan dari metode ini adalah keakurasiannya karena penentuan kesetimbangan tekanan berdasarkan fall rate yang merupakan karakteristik dasar dari DWT. Akan tetapi, karena kesetimbangan tekanan tidak ditentukan secara langsung berdasarkan nilai tekanan melainkan fall rate, hanya operator yang berpengalaman yang bisa melakukan kalibrasi DWT dengan metode ini dan tingkat kesulitannya akan bertambah apabila mendapatkan DWT yang memiliki piston yang tidak sensitif (Ega & Samodro, 2017).…”