The error of refueling is caused by the standard conditions. It is difficult to ensure the consistency between the use conditions and the verification conditions during the use. Therefore, if we don't pay attention to the conditions of the use process, there will be some additional errors, including: the quality of the design and manufacture of the fuel dispenser, especially the quality of the flowmeter and the reliability, stability and accuracy of the computer components, the accuracy of the indication device display, the over impulse of the computer fuel dispenser, the configuration of the oil and gas separator, the selection of the hose, etc.
According to the above analysis, the countermeasures to control the errors of the refuelling machine are put forward.
- Quality assurance of newly installed fuel dispenser
The stability of long-term operation and reliability of comprehensive quality should be considered for the fuel dispenser model. The user shall follow up the quality inspection of the manufacturer. For the quality tracking of the production of the gas dispenser, it is not easy to understand the first verification and in use verification of the measurement error and indication error, and the performance inspection of the fuel dispenser should be carried out regularly.
- The indication device shall meet the accuracy requirements
"verification regulation of fuel dispenser" specifies that the minimum fuel supply variable of the fuel dispenser shall be less than 0.05l, and it is also specified that there shall be 3 digits after the decimal point of the volume filling volume display unit of the computer fuel dispenser. However, the general gas dispenser usually displays only 1-2 decimal places after the decimal point, and the accuracy is obviously not enough. It is suggested that when the accuracy of flowmeter is 0.15%, and 200 pulses are sent out by pulse generator per liter, it is more appropriate to take 3 decimal places after the decimal point of the display device.
- Pay attention to the impact of overshoot
To solve the impact of overshoot, one is to install solenoid valve, which will change from large flow to small flow before shutdown, so that the motor can not be thrust phenomenon, so as to solve the overshoot problem of preset refueling. Second, set the amount of shutdown in advance.
- The adjustment mechanism shall meet the technical requirements
Generally, screw the adjusting screw inward (clockwise), that is, reduce the discharge; when it is turned out, increase the fuel filling amount. Screw one button every inward to reduce the discharge fuel by 0.000283l. When one screw is screwed in two turns or two screws are screwed in one turn each, the volume accuracy will change by about 1 / 1000. When the original standard adjusting screw is screwed to the limit, the accuracy of the fuel dispenser is still ± 3%, so as to make the accuracy close to ± 0.3%. To make up for the loss, the standard screw is often replaced with the screw with the screw with the length of about 10 mm.
- Qualified oil and gas separator
If the liquid measured by the flowmeter contains a certain amount of gas, it will directly affect the metering accuracy of the flowmeter. Therefore, when the measured oil may contain air or decompose gas, an oil and gas separator shall be arranged in the fuel dispenser. According to the regulations, for the liquid with viscosity less than 1mpa.s, the oil-gas separator shall be able to separate 20% of the gas content; for the oil with viscosity greater than 1mpa.s, its separation capacity is 10%.
- Select the appropriate hose
The change of the volume in the hose will also affect the accuracy of the fuel dispenser. The volume of change of hose content is related to the material, performance and use length of the hose. It must be strictly limited and configured according to the regulations.