Vortex Steam Flow Meter issues with gas measurement

The problems of vortex flowmeter in coke oven measurement are mainly caused by two aspects. First, the measurement problem is caused by the vortex flowmeter itself or related equipment. Second, the measurement problem is caused by the site environment and pipeline system. 

Vortex Steam Flow Meter with Gas Measurement

Today, ARTang mainly introduces to you which environmental and pipeline system factors will cause the output signal of vortex flowmeter to be unstable when measuring coke oven gas. The reasons for the unstable output signal of flowmeter are as follows.

1.The fluctuation of vortex flowmeter output signal is caused by pulsating flow in the pipeline.

Coke oven gas has high temperature and high humidity when it leaves the factory. Therefore, the gas pipeline measured by the vortex flow meter contains moisture, and the gas flow drives the moisture to fluctuate reciprocating, thereby forming a pulsating flow (pulsating flow will cause the meter output signal to fluctuate or jump, and meter can't measure gas flow).

2.Unstable output signal is caused by the condense and volatilize of impurities in the gas pipeline.

The coke oven gas pipeline contains a lot of impurities. When the temperature in the pipeline is low, impurities condense on the sensor head, the sensitivity of the sensor will reduce, and the measurement error of meter becomes larger; when the temperature of the measurement pipeline rises, the impurities condensed on the sensor head volatilize, and the sensor sensitivity will increase. Thus, the continuous changing of sensor head sensitivity will cause variable output signal of vortex meter.

3.The jumping output signal of vortex meter is caused by unqualified wire pressing method.

During the wiring process of the vortex flow meter, if the copper wire in the sensor and the crimping terminal are not connected properly, the signal will be discontinuous during the transmission process, which will cause the output signal to fluctuate and it will be impossible to obtain an accurate flow reading.

4.The wrong output signal is caused by the non-standard grounding wire of the vortex instrument.

The grounding wire of the vortex meter is not consistent with the specification requirements,non-standard grounding wire will cause 50 Hz interference in high current enter.Under this situation ,if the normal signal is higher than 50Hz,the normal signal will be output.Otherwise it will output the wrong signal.

5.Incorrect output signal of vortex instrument is caused by improper installation position.

If the vortex flow meter is installed in a site with frequent magnetic field change, the vortex instrument will output a signal higher than the normal value, so there will be measurement errors. The vortex meter only output normal signal when the magnetic field is stable.

Selection of Vortex Steam Flow Meter

The vortex steam flow meter is divided into 3 types of sensors: flange type, clamp type, and insertion type. The flange type is the most widely used type, and the clamp-on type is the most widely used type. Clamping type flowmeter, insertion type flowmeter in the installation is very easy to affect the accuracy, and once the installation is not scientific and standardized, will cause inaccurate measurement, error phenomenon. Insertion vortex flow meter is mainly used in the occasions that do not require precise control and measurement.

The vortex steam flow meter is also available in one-piece and two-piece versions. If in a high temperature state, or in the high altitude, well installation, usually applied to the split-type meter, the main purpose is to improve the working environment of the meter, while convenient maintenance of the meter. In the process of implementing the integral type meter, it is necessary to leave enough space around the installation point, in order to facilitate the installation and wiring, as well as to make future maintenance work more convenient.

Temperature and Pressure Compensation of Vortex Steam Flow Meter

In the process of steam measurement, the work that needs to be done is the saturated vapor compensation, which is applied in two ways, one is pressure compensation and the other is temperature compensation. Usually has two specific compensation modes, namely: if the vortex flowmeter sensor does not have a temperature detection element and built-in pressure, only in the instrument can be implemented within the static compensation, that is, the compensation is to take a fixed pressure value, the temperature value of the input method to achieve. This mode is more suitable for occasions where there is no large temperature and pressure change. In the case of a vortex flowmeter sensor with a temperature detection element and built-in pressure, the instrument takes into account the results of the measured temperature and pressure to grasp the state of the steam and determine which type of steam is superheated or saturated. For mass flow, the calculation requires access to a database of steam indicators stored in the instrument to perform intelligent calculations, and the use of a steam flow totalizer, which transmits the volumetric flow rate and temperature measured by the vortex flowmeter, as well as signals measured by the pressure transmitter. Steam flow totalizers have built-in compensation algorithms for superheated and saturated steam, and can accurately output mass flow rates and standard volume flow rates, as well as correctly output heat and specific enthalpy.