Thread Content
This article is reproduced from: http://china-rosemount.cn/DT/383.html. Keywords for this article: Rosemount, http://china-rosemount.cn/. Rosemount transmitters are not used very frequently in daily applications; most customers consider the price of these instruments to be high, exceeding their expectations. So some customers may wonder why this instrument is relatively expensive Below, the editor will provide answers for everyone. The boiling point of the filling fluid in Rosemount transmitters generally decreases as pressure drops. If the flange transmitter operates under negative pressure, a vacuum will inevitably occur within its sealed system, which lowers the boiling point of the filling fluid and leads to vaporization. However, if the temperature of the medium drops below the boiling point of the filling fluid, vaporization occurs. If the medium temperature is much higher than the boiling point of the filling fluid, the vapor pressure of the filling fluid will be very high. This not only exerts pressure on the sensing element of the transmitter, causing measurement errors, but also causes the diaphragm to bulge outward, leading to permanent deformation. When the transmitter operates under conditions of high temperature and high vacuum, the filling liquid is in a condition where it vaporizes very easily. For these reasons, we treat such transmitters in a special manner: the filling fluid used in the diaphragm box must be high-temperature silicone oil, and the amount of fluid filled must be precisely controlled – neither too much nor too little. Any gas present in the silicone oil must be completely removed before filling, and the diaphragm box must be evacuated to an absolute vacuum with no residual pressure left. The welding of the diaphragm box must also be absolutely secure. All of this increases the processing workload and cost of the transmitter, which is why flange transmitters for high temperature and high vacuum environments are particularly expensive. The above explains the reasons why Rosemount flanged transmitters are relatively expensive. Therefore, when purchasing this instrument, we need to determine based on our actual situation whether it is truly essential. Shanghai Mengyan Automation Equipment Co., Ltd. Address: Room 1119, Jiahong Building, No. 639 Guangfulin Road, Songjiang, Shanghai. Contact person: Xu Gong. Mobile phones: 18616582302 / 18616582330. QQ: 764861476. Email: sales@shmyzdh.com