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The common fault treatment method of nozzle flowmeter

Dec 25, 2018

The common fault treatment method of nozzle flowmeter

Nozzle flowmeter is a differential pressure generating device to measure the flow rate. It can measure the flow rate of various fluids in the pipeline with various differential pressure meters or differential pressure transmitters.Standard nozzle throttle device and differential pressure transmitter are used together to measure the flow of liquid, steam and gas, widely used in petroleum, chemical, metallurgy, electric power, light industry and other departments.

The common fault treatment method of nozzle flowmeter

The nozzle flow transmitter is composed of the nozzle flow sensor and the differential pressure transmitter, and outputs 4-20ma electrical signals representing the difference pressure signal size. 

The flow calculation, temperature and pressure compensation are completed by the user in addition to configuration.There are two kinds of structure, one - piece installation and one - piece installation.The integrated installation is that the differential pressure transmitter has been connected with the nozzle as a whole when the product is delivered from the factory. After the user purchases the integrated nozzle, there is no need to connect the pressure guide pipe again when using it.But must match the corresponding flow calculator, pressure transmitter and temperature transmitter.The split nozzle flow transmitter consists of an independent nozzle flow sensor and a differential pressure transmitter.The connection between nozzle flow sensor and differential pressure transmitter is completed by the user.

Characteristics of nozzle flow sensor: only the formation part of differential pressure signal (nozzle part) is provided, and the differential pressure transmitter and flow calculation display part are not provided. The output signal is the pressure difference formed before and after the throttle part.Other configurations are made by the user himself.

The common fault treatment method of nozzle flowmeter

The common fault treatment method of nozzle flowmeter

Nozzle flow meter has simple structure, sensor inside the empty, no additional resistance loss of durable resistance to wear, can maintain enough high measurement precision, long-term use, combined with intelligent instrument for completely can be used as a measurement inspection instrument use repeat precision is high, this feature is particularly suited to the process flow and control flow measurement of welding installation, ensure that bend sensor without leaking for a long time, safe operation and low requirement for straight pipe is very convenient to use, in the narrow applicability with different pipe material and suitable geometry size,The flowmeter can be used to measure the flow rate of most process media and conditions in alkali making system.

Method of exhaust valve of nozzle flowmeter:

1. If air is measured together with other non-condensable gases and steam, the figures shown in the flowmeter do not reflect the actual amount of steam used.

2. If the water in the tank of the steam system, such as the water in the deaerator has not been processed physically or chemically, the mixing ratio of steam and air may be more than 80/20, which will lead to a measurement error of more than 20%.

3. Automatic exhaust valve is based on the temperature of steam separated from the steam/air mixture of the full gas, the temperature of pure steam is much higher than the temperature of steam/air mixture, when in the steam temperature, the disc of the automatic exhaust valve will expand, at this time must close the valve, prevent the steam through.

4. When the temperature is lower than the saturated steam temperature, the disc will shrink and the valve will be opened to discharge the steam/air mixture gas system. The automatic exhaust valve should be installed in front of the pipe of the steam flow meter.The electric field should take some measures to reduce interference or strengthen the shielding treatment of signal line.

The common fault treatment method of nozzle flowmeter

When the nozzle flowmeter is in normal flow, the sensor output signal is unstable:

1. Irregular vibration exists in the pipeline.Find the source of vibration, eliminate the vibration of pipeline or process pipeline vibration reduction treatment.

2. Incorrect gain of amplifier plate.Use oscilloscope to check the waveform of output signal. If there are multiple waveforms or waveforms lost, it indicates that the amplifier board is not working normally. Multiple waveforms indicate that the gain is too large, and waveforms lost indicate that the gain is too small