The Study Of Intelligent Flow Totalizer Based On Zero Power Pulse Sensor

According to the interior actualities that a great deal of mechanical rootsflowmeters are widely used in natural gas flow measurement, a sort of intelligent flowtotalizer based on zero power pulse sensor is developed in this paper. The flowtotalizer combines the measurement principle of roots flowmeter with the single chipmicroprocessor and a multifunctional and digital intelligent head of the totalizer isempoldered which is equipped with some electronic circuit and software .The Wiegand sensor which is a kind of zero power sensor is choosed as theimpulse sensor. The application of the Wiegand sensor improves the performance ofthe signal acquisition and it can measure the turns of the mechanical rator accurately.At the same time, the sensor does not consume electric energy of the system, so therealization of the totalizer with low power and high accuracy flow measurement isoffered the favourable base. In the full range the meter factor is revised in subsectionaccording to the change of the pluse frequency , so that the factor gains the exact data.The acquisition of the pluse frequency is performed by two methods which includedirect acquisition and measuring the pulse cycle according to the condition which iseither large flow or small flow. In order to get the high accruacy temperature andpressure compensations, the compression factor Z is used to remedy the limitation ofstate equation of ideal gas. On the base of theorem of corresponding states, the paperdeduces a simple and exact mathematical model for calculating the compressionalfator and the method is benificial to the realization of the single chip microprocessor.In addition, there is wireless data transmission module based on GPRS and standardcurrent output module in the system that can be chosen by the factual requirement.And either of modules is chosen, the system must be equipped by the external powersupply.The theoretical and experimental result proves that the intelligent flow totalizerhas favourable performance in low power and high accuracy. The design is feasibleand the totalizer is being applied step by step in the market.