Service Report for Hanzhong Bayi Zinc Industry

I. Report Overview:

This after-sales report mainly focuses on the on-site problem analysis and solutions for the vortex flowmeters sold by our company, so as to ensure the customer’s accurate flowmeter selection and stable measurement in the future. This report will elaborate on the after-sales service process, the on-site situation understanding and problem analysis by technical personnel, as well as the customer’s subsequent judgment methods and solutions.

II. Service Process:

Arrange the itinerary and communicate with the customer about the on-site arrival time.

Survey all on-site instruments, and based on the survey results, provide on-site conclusions and improvement methods.

III. On-Site Problem Manifestations:

For the DN250 caliber vortex flowmeter, the flow data in October is significantly lower than that in September.

The on-site temperature and pressure of some instruments are extremely low, and the temperature difference of some even reaches 50℃, which results in an extremely low overall flow rate.

For the DN200 caliber vortex flowmeter (in Workshop 4), when it operates at full load, the flow rate not only fails to increase but also decreases proportionally.

The waterproof plug for on-site wiring is damaged and exposed outdoors.

Most of the instruments are installed near the gas distribution manifold. The two DN250 vortex flowmeters on-site exhibit obvious vibration, and the vibration can be clearly felt by touching the pipeline with hands.

The on-site pressure of the DN150 caliber vortex flowmeter is lower than 1 Kg, ranging from 60 to 80 Kpa, and the temperature is only 121.9℃, which results in a density lower than 1 Kg/m³.

In the on-site system, only instantaneous flow and cumulative flow are collected, while pressure and temperature data are not collected.

The DN400 vortex flowmeter has inaccurate measurement. It is too high to approach and observe, and we learned that it was installed to replace the original differential pressure flowmeter.

IV. Problem Analysis:

Fluctuations in temperature and pressure have caused the data to be lower than expected. Meanwhile, during the on-site inspection of the DN250 caliber flowmeter, it was found that its flow rate is only 4-5 t/h even when operating at full load. Through preliminary analysis, it is determined that there is an issue with on-site model selection.

The DN400 caliber flowmeter is oversized in model selection. A vortex flowmeter was used to replace the original orifice plate flowmeter. Due to the flowmeter’s excessive height, we could not approach it for observation. However, based on the working principles of the two types of flowmeters and the on-site reported symptoms, it is analyzed that the measurement deviation of this vortex flowmeter should also be caused by the flow rate being lower than the lower limit.

When the DN200 vortex flowmeter (Workshop 4) is in full-load operation, its flow rate decreases significantly. According to the data on the on-site integrator, the density is 1 Kg/m³, while the actual flow rate is approximately 16 t/h—this flow rate is far higher than the designed flow capacity of the DN200 caliber. Based on the measurement characteristics of vortex flowmeters, when the flow rate exceeds the upper limit, it will decrease sharply in proportion. Hence, the phenomenon of flow measurement deviation occurs.

The on-site pressure and temperature are generally very low. This may be caused by the requirements of the production process, or it may result from inaccurate pressure regulation due to equipment performance degradation or poor steam quality.

V. Recommendations and Improvements:

Increase the recording of temperature and pressure data, with a recording cycle of six months. This data can be used as a reference for the equipment inspection and model selection work in April next year.

For the DN250 flowmeters in the later stage, necking can be considered based on the actual on-site conditions.

For the DN200 flowmeter in Workshop 4, either expanding its diameter to DN300 or diverting part of the flow to other workshops via a bypass can be considered, based on the actual on-site conditions.

When selecting a flowmeter, both the maximum flow rate and minimum flow rate must be taken into account. Only in this way can a flowmeter with an appropriate caliber be chosen, and the measurement will be more accurate.

The pipe loss factor must also be taken into account, and the installation position of the flowmeter should comply with the basic requirements for straight pipe sections.

Regarding the current situation where some flowmeters have inaccurate measurement due to relatively low temperature and pressure, it is recommended to slightly increase the pressure in the pressure regulation section to see if there will be any improvement.