Lanzhou Lubricating Oil Factory is one of the main manufacturers of PetroChina Kunlun lubricating oil, with eleven automatic filling production lines, of which only the earliest three 4L oil filling machines are volumetric, and the other eight oil filling machines are all weighing, and the early volumetric filling machines have been basically replaced by weighing filling machines.

Measurement accuracy as part of the quality of packaged oil products, with the improvement of the user's quality awareness and national quality standards, accurate measurement in the production of packaged oil is increasingly important. Improve the metering accuracy in the oil filling process, not only to avoid the short amount of oil and affect the image of the brand, but also to avoid overfilling and bring economic losses to the enterprise.

In this paper, Lanzhou lubricating oil plant in the barrel oil filling machine as an example, for weighing filling equipment in the measurement of problems, through a large number of on-site data analysis, to find out the main factors affecting the accuracy of filling measurement, put forward in the barrel of the filling machine metering to improve the measures, the implementation of the implementation of the good results achieved.

2 in the barrel automatic filling machine composition and workflow

2.1 Composition

Lanzhou lubricating oil plant in 1999 the introduction of the Italian SASIB company's RAPP8 / 60-type automatic liquid filling machine, the equipment can be completed from 15 liters to 20 liters of open containers of liquid products filling, measurement for the electronic weighing instrument, the control mode for the automatic filling controller. RAPP8 / 60-type weighing filling machine, by the power ramp line, filling weighing line, the main filling machine, unpowered Ramp line, electric control system and gas system, etc., working schematic diagram in Figure 1.

2.2 Workflow

RAPP8/60 type weighing and filling machine is in-line, continuous liquid filling equipment, the barrels in turn through the 2 #, 3 # 4 filling nozzles for coarse filling, to the 5 # filling nozzles for accurate filling, conveyor belt to the next process. The workflow is: manually put the empty barrels on the automatic liquid filling conveyor chain, push the barrels to push the empty barrels to the filling weighing line 2 # filling station, 2 # electronic rise, put the barrels delayed to the point, the weight value of the empty barrels were picked for automatic tare, and then the filling head opens to start a large flow of fast pre-filling, to reach the amount of pre-filling, 2 # electronic scales come down, the middle barrels go into the 3 # # 4 # filling nozzle in turn to the coarse filling (3 #, 4 # filling nozzle without weighing equipment, filling volume according to 2 # filling nozzle filling time to determine the length), after the barrel into the 5 and filling station, 5 # electronic scales rise, filling nozzle filling to coarse shut-off valve set value after the transfer of small flow rate slow filling, filling to the fine shut-off valve set value of the quasi-filling head is completely closed; filling is completed after the filling scales heavy line again to start the filling scales driven by the heavy line will be the heavy barrels to the next After the filling is completed, the filling weighing line starts again, and the filling weighing line drives the heavy drum to the next process, and the filling weighing work is completed.

3 Problems

3.1 Filling measurement deviation

National "supervision and management of quantitative measurement of packaged goods," the provisions of the 20L barrel single barrel measurement error of 160g, I Guang internal control standards for the earth 100g. In the actual filling operation, the single barrel error value in a 130g +150g between the maximum overweight 150g.

3.2 Filling efficiency is low in order to ensure that the filling of oil products measured accurately, the operator needs to stop often to adjust the filling volume, delaying production, reducing the filling efficiency.

4 Problem Analysis

In view of the above problems, we CD40 diesel oil as a representative of the filling process to collect data, through the collection of more than 90 groups of measurement data, analysis of the oil volume change rule, found that the filling accuracy is not accurate, measurement of large deviations in the problem is mainly affected by three factors.

The kinematic viscosity of CD40 diesel engine oil (mm/s, 100C) is: 12.5-16.3

Packaging: 100 20L injection molding drums, average tare weight 1.13kg filling parameters: 2 # filling nozzle pre-filling volume: 2.5kg filling net total (5 # weighing instrument measured net filling volume): 16.0kg; single barrel allowable metering error: earth 100g

4.1 The impact of oil temperature changes on filling accuracy

In the low-temperature state of the oil, high viscosity flow rate is slow, the oil in the filling process on the electronic scales of the impact of small, relatively high filling accuracy, measurement error is small, the single barrel measurement error within the prescribed range; but as the temperature rises, the viscosity of the oil decreases, the oil in the filling process on the electronic scales of the impact of the oil to increase, the oil filling accuracy decreases, the measurement error increases, the error in the 110kg ~ 10 150g between, the error exceeds the permissible error of 100g, and the measurement error exceeds the permissible error of 100g. The measurement error exceeds the allowable error of 100g.

4.2 Influence of the size of the filling nozzle aperture on filling accuracy

In order to reduce the impact of oil on the electronic scale during the filling process, the filling nozzle is installed with different apertures of the guide hole, 5 # filling nozzle guide hole aperture from 4mm to 2mm after the transformation of the oil in the filling process on the electronic scale to alleviate the impact of the filling process to improve the filling accuracy. Table 2 is a set of data of 20L injection molding barrel net filling volume of 16.0kg when 5 weighing instrument measured 5# filling nozzle aperture of the flow guide hole from 4mm to 2m after the transformation of a set of data.

At the same temperature, 5 # filling nozzle aperture by 4mm transformed into 2mm, the filling process of the oil on the electronic scale to reduce the impact of the relative filling accuracy to improve, the error in a 40g ~ 1060g between the error is less than the permissible error of 100g, the measurement error of a single barrel in the range of the provisions of the effect is more satisfactory.

4.3 Influence of filling parameters on filling accuracy

The 2# filling nozzle valve is opened to the minimum, 3#4# filling nozzle valve is opened to the maximum, 2# pre-filling volume is set to the maximum value of 4.61kg, by prolonging the 2# filling nozzle filling time, to increase the 3#4 filling nozzle pre-filling volume, so that through the 4# filling nozzle filling of the net weight of 15kg, to the 5# filling nozzle only the remaining 1kg for accurate filling.

At the same temperature, after replacing the guide hole, adjust the size of the 2 #, 3 #, 4 # filling nozzle valve opening, increase the 234 # filling nozzle pre-filling volume, reduce the 5 # filling nozzle filling volume, reduce the filling process on the impact of the electronic scales, the oil filling accuracy can be controlled in between the Shi 10g, the error is less than the allowable range of Shi 100g, the effect is very satisfactory.

5 measures to improve the accuracy of filling measurement

5.1 low-temperature Bay and keep the oil temperature stable

Temperature changes have a greater impact on the filling accuracy. In the actual production process, under the premise of not affecting the filling speed, should be appropriate to keep the oil at low temperatures, increase the viscosity of oil, is conducive to improving the filling accuracy. In actual operation, summer should be prohibited to fill the oil for heating, filling at room temperature is more appropriate; winter can be turned on in advance of the electric accompanied by heat to the filling of oil for preheating, reduce the start-up process of the oil temperature of the substantial changes in the temperature of the oil will be kept at a relatively stable temperature, is conducive to improving the filling accuracy of the oil.

5.2 Adjust the flow guide hole of 5# filling nozzle.

Replace the guide hole of 5# filling nozzle, change the diameter of the guide hole of 5# filling nozzle from 4mm to 2mm, and increase the filter to reduce the impact of the oil on the electronic scale during the filling process.

5.3 Setting filling parameters of filling machine filling

(1) Open the manual control valve valve of 3#4# filling nozzles to the maximum.

(2) During precise filling, the opening of the manual control valve of the 5# filling nozzle should always be kept at the minimum, with the purpose of reducing the impact of the oil on the electronic scale during precise filling, and ensuring that the 5# filling nozzle can carry out precise filling.

(3) After the start-up of each shift, the filling time of 3#4 filling nozzles can be prolonged by adjusting the parameter of pre-filling volume of 2# filling nozzles for coarse filling according to the change of oil temperature to ensure the filling volume of 3#4 filling nozzles. When the oil temperature is high, increase the pre-filling volume of 2# filling nozzle; increase the filling time of 3#4# filling nozzle; when the oil temperature is low, reduce the pre-filling volume of 2# filling nozzle and increase the filling time of 3#4# filling nozzle.

(4) Parameter setting for different volume barrels; when filling 20L (oil net weight 16kg barrels, set the pre-filling parameter of 2# filling nozzles to 4.61kg on the operation panel, and the 4# filling nozzles must fill out the amount of 15kg net weight; when filling 16L (oil net weight 14kg) barrels, set the pre-filling parameter of 2# filling nozzles to 4.0kg, and the 4# filling nozzles must fill out the amount of 13.5kg net weight; if the oil temperature is low, then reduce the pre-filling amount of 2# filling nozzles, and increase the filling time of 3# and 4# filling nozzles. When filling 16L(net weight 14kg) drum, the pre-filling parameter of 2# filling nozzle is set to 4.0kg, and 4# filling nozzle must fill out the amount of 13.5kg net weight, and then 5# filling nozzle will fill out the amount accurately to ensure the accuracy of filling.

6Effective analysis

After the above adjustments, the filling accuracy of the metering filling machine can be maintained between 10g, which not only establishes the high-quality image of Kunlun brand, but also reduces the economic losses caused by overfilling oil products throughout the year.

7 Conclusion

Through the analysis of the automatic filling machine metering problems, put forward measures to improve the metering accuracy of the filling machine, to solve the problem of poor metering accuracy of the filling system; the same measures will be applied to other weighing oil filling machine, similar adjustments, found to have a better effect.