Frequently asked questions about liquefied gas turbine flowmeters

Project Overview

The intelligent liquid turbine flow meter is a new intelligent instrument that integrates turbine flow sensor and display, developed using advanced ultra-low power consumption single-chip microcomputer technology. It adopts double-row LCD on-site display, has a compact structure, intuitive and clear readings, It has obvious advantages such as high reliability, no interference from external power supply, lightning resistance, and low cost.

(1) Before use, check whether the upstream pipe of the turbine flowmeter is clean. Pay special attention to removing foreign matter in the pipe, such as welding slag, etc.

(2) When the turbine flowmeter is put into operation, for the flow sensor without a bypass pipe, the upstream valve of the flowmeter should be opened at a medium opening first. Then slowly open the downstream valve. Run at a smaller flow rate for a period of time (about 10 minutes), then fully open the upstream valve, then open the downstream valve to a large degree, and adjust to the required normal flow rate.

(3) For flowmeters installed with bypass pipes, first fully open the bypass pipe valve, open the upstream valve of the flowmeter at a medium opening, then slowly open the downstream valve, and close the bypass valve to open degree, allowing the instrument to run at a smaller flow rate for a period of time. Then fully open the upstream valve, fully close the bypass valve (make sure there is no leakage from the bypass valve), and then adjust the opening of the downstream valve to the required flow rate.

(4) For low-temperature and high-temperature fluids, the water in the pipeline must be drained before circulation. When flowing, run at a very small flow rate for 15 minutes, and then gradually increase to the normal flow rate. When stopping the flow, it should also be done slowly so that the pipe temperature and the ambient temperature gradually approach.

(5) The opening and closing of the valve should be as gentle as possible. If the opening and closing of the valve is automatically controlled, it is best to use the "two-stage opening, two-stage closing" method to prevent the fluid from suddenly impacting the impeller or even causing water leakage. Hammer phenomenon damages the impeller.

(6) When the pipeline pressure is not high, the pressure downstream of the flow meter should be checked. Generally, in the initial stage of operation, observe whether the pressure downstream of the flow meter is greater than Pmin when the flow rate is large to prevent cavitation.

(7) Correctly use the instrument coefficient of the flow meter. The instrument coefficient K of the turbine flowmeter is filled in by the manufacturer on the certificate given to the user, so be careful not to lose it. After long-term use of the turbine flowmeter, the instrument coefficient K will change due to bearing wear and other reasons, and it should be calibrated regularly on-site or offline. If the measurement error exceeds the range, the spare movement should be replaced in time, and the display instrument should be reset in time according to the new instrument coefficient.

(8) Pipelines and flowmeters must be cleaned regularly. The flow direction, flow rate, pressure, temperature, etc. of all fluids during pigging should comply with turbine flow.

(9) For flowmeters with a diameter of DN200 or above or high-pressure pipelines, the oil method should be based on the manufacturer's regulations. Be careful not to refill oil frequently. Generally, the flowmeter is equipped with an oil filling system.

(10) It is forbidden to operate at excessive flow for a long time. Operation at excessive flow will seriously damage the movement.

(11) Skill training for on-site operators should be strengthened, Reduce human damage factors to the flow meter.

2. Precautions for debugging and use

(1) On-site installation and maintenance must comply with the warning "Do not open the cover when there is explosive gas", and turn off the outside before opening the cover.

(2) When the product is used outdoors, it is recommended to add a protective cover.

(3) The selection should be within the specified flow range to prevent overspeed operation in order to obtain ideal accuracy and ensure normal service life. (Overspeed operation due to pressure testing, purging pipes or exhaust, and turbine operation in reverse flow may cause damage to the flow meter).

(4) When the flow meter is put into operation, the valve should be opened slowly. Prevent the turbine from being damaged by instantaneous airflow impact.

(5) Lubricating oil should be added according to the notice. The frequency of lubricating oil depends on the cleanliness of the air, usually 2 to 3 times a year.

(6) It is not allowed to open the back cover or change the relevant internal parameters when the flow meter is running, otherwise it will affect the normal operation of the flow meter.

(7) Do not loosen the fixed part of the flow meter at will.

(8) Protection of pressure sensor. When using a flow meter, users should note that the pressure overload value of the flow meter is 1.5 times the rated working pressure of the pressure sensor (i.e. 1.5 times the high pressure of the medium).

3. Use and maintenance of liquid turbine flowmeter

(1) When using it, the liquid to be measured should be kept clean and fibrous debris should be avoided. It is ideal to use it in LCST. Although the performance of the sensor is offset when used in larger than lcst, it can meet certain requirements. When the liquid viscosity is greater than 15cst, calibration should be performed under working conditions.

(2) The maximum working pressure of the sensor must be in accordance with regulations and does not allow overloading. Any changes in other parameters should be reported to the manufacturer in advance.

(3) The wear-resistant material of the movable part of the sensor is relatively brittle, so large vibrations should be avoided during installation to prevent short cracks.

(4) Select an appropriate sensor according to the size of the measured flow rate. Since the sensor transmission is entirely powered by fluid, it is recommended not to use the lower limit of the sensor flow rate as much as possible in order to obtain better measurement results.

(5) During use, it is strictly forbidden for the sensor to be impacted by high-speed fluid without liquid. The sensor should be slowly filled with liquid before opening the outlet valve.

(6) Clean and repair the sensor regularly according to the actual situation of the user.