2020.02.06
Summary:The automatic filling machine drives the servo motor to complete initialization and adding liquid according to the actual situation on site. At the same time, it receives information from the electronic scale to coordinate the liquid filling relationship and control the out-of-tolerance filling. With the weighing controller as the control core, the weighing machine The analog signal detected by the heavy sensor is converted into a digital signal for calculation and comparison.
1 Preamble
In the entire production process of edible fats and oils, and consumers close relationship in addition to the quality of edible fats and oils and packaging, the net content of small packages is also one of them. As an enterprise producing small packages of edible fats and oils, on the one hand, it should always ensure the rights and interests of consumers and ensure that the products meet the requirements of relevant laws and regulations, on the other hand, it should also take into account the economic benefits of the enterprise and try to minimize the loss of fats and oils in the process of packaging.2 Relevant laws and regulations on the packaging of edible fats and oils
The current quantitative packaging measurement management regulations for the People's Republic of China General Administration of Quality Supervision, Inspection and Quarantine on January 1, 2006 implementation of the "supervision and management of measurement of quantitatively packaged goods".
According to the provisions of the edible fats and oils (belonging to the volumetric category) of the unit of measurement for the volume unit, respectively: milliliters (ml or mL), liters (1L), the same time, the approach provides that: batch of quantitatively packaged commodities should be greater than or equal to the average actual content of the net content of its labeling.
3 edible fats and oils in the process of automatic filling machine measurement control
Measures for Supervision and Management of Quantitative Packaging Commodity Measurement" stipulates that the measurement method of edible fats and oils is density method. However, in the actual production site, constant temperature, precision measuring instruments (density cups or density instruments), demanding testing techniques, relatively long testing time and other issues make the implementation of this method is more difficult; generally used in the production site to control the weight, the actual density determination, calculation, etc. in the laboratory to complete.
Measurement control in the actual production process, in order to ensure that to meet the "measurement of quantitatively packaged goods supervision and management measures" requirements, generally on the filling system to calculate a standard value, based on the performance of the equipment to set a higher than the standard value of the control baseline and the range of deviation, and based on the detection of density / specific gravity will be converted into a weight range; the operation of the site, through the electronic weighing, check the actual weight On-site control is realized by weighing and checking whether the actual weight is within the control range.
The difference between the control baseline and the standard line is the biggest cause of loss in the production process of edible oil packaging, and the difference should be minimized, which is determined by the precision of the filling machine, the temperature of the oil and the production speed.
4 Measurement errors and solutions
Measurement error of filling of edible oil and fat automatic filling system includes the error in production (hereinafter referred to as "production error"), as well as on-site weighing error.
Edible oil and grease metering filling machine filling in the measurement error mainly includes equipment mechanical accuracy, filling temperature changes in the oil and grease produced by the error, due to the production speed adjustment and start and stop the error generated.
4.1 Filling machine precision
Weighing filling machine precision mainly refers to the repeatability and stability of its filling volume, which can be selected through the quality of excellent performance of the equipment to reduce this part of the error. At the same time filling machine accuracy is a key factor in setting the control baseline, which determines the difference between the control baseline and the standard value and the size of the deviation range.
4.2 Canned grease temperature changes generated by the error
4.2.1 Temperature change factors
Due to the influence of climate and other related factors, in the actual continuous production, the temperature of filling grease will produce certain changes. This temperature variation is mainly related to two factors.
①Temperature difference between large outdoor tanks
The temperature difference between the upper and lower layers of the tank can be up to about 4 ℃ (the upper layer is higher than the lower layer); and in winter due to the role of geothermal heat, this phenomenon is just the opposite, the temperature difference between the upper and lower layers of the tank can be up to about 2 ℃ (the lower layer is higher than the upper layer).
This temperature change for automatic filling machine is more gentle, and in a relatively short period of time is not obvious. Generally, it can be controlled by weighing and testing the packaged products in a certain cycle, and adjusting the filling equipment according to the test results.
② Temperature difference of the pipeline
In the case of a long outdoor pipeline, the temperature of the liquid in the pipeline may be caused to rise due to the action of sunlight. In the normal operation of the weighing and filling machine, due to the factors of the flow of oil and grease in the pipeline, this effect will not be very large, and the temperature of the oil and grease entering the canning equipment will basically not be affected. However, for companies that are not in continuous production (e.g., companies that have a long lunch break at noon), the temperature of the grease in the pipeline outdoors may reach a higher temperature due to the exposure to the hot sun. According to tests, this elevated temperature can be up to (10~20)°C. For this temperature situation, it can be solved by adding insulation or using underground piping.
4.2.2 Filling measurement error generated by temperature change
According to the relevant reports, if the temperature changes every 1 ℃, the corresponding change of 5L of grease is about 3.2ml (or 3g), i.e.: in the absence of temperature compensation of the volumetric filling machine filling, if the temperature rises by 1 ℃, the corresponding filling volume decreases by about 3.2ml (or 3g); on the contrary, if the temperature falls by 1 ℃, the corresponding filling volume increases by about 3.2ml (or 3g).
4.3 Error generated by production speed adjustment
Due to the high viscosity of fats and oils, the fluidity is relatively poor compared to water.3 Therefore, the actual filling operation cycle of the weighing and filling machine generally includes two processes: "filling" and "drying"; at the same time, during the operation process of "drying", the filling volume is increased by about 3.2ml (or 3g). In the process of "drip-drying", taking into account the filling speed of the liquid filling machine, "drip-drying" is not really a complete "drip-drying", but "drip-drying" to a relatively acceptable level, and "drip-drying" to a relatively acceptable level, and "drip-drying" to a relatively acceptable level. "to a relatively acceptable, does not affect the operation of a degree. At this point, through the metering control of the filled product can ensure that the net content of the final product to reach the range of control; but when we adjust the speed of the metering filling machine, the filling cycle "filling" process will not change the time consumed, the corresponding change is the "drip-drying The corresponding change is the time consumed by the "drip-drying" process, which results in a change in the amount of grease dripping into the bottles. The result is a change in the amount of grease dripped into the bottle. This change will not have a significant effect if the speed adjustment is not changed significantly.
In order to solve the resulting measurement error, when adjusting the production speed, strengthen the measurement of the filling product sampling, to ensure that the resulting measurement error within the control range; in the temporary parking after driving, the first filling of the product to carry out the necessary tests.
4.4 On-site weighing error
Site weighing error is mainly the accuracy of electronic scales and electronic weighing of the site level adjustment and other errors, such as general control of the weighing of the following 5L is best equipped with a resolution of 1g electronic weighing, and at the same time in the operation of the site, pay attention to the adjustment of the level of electronic weighing and other measures to control.
Edible oil filling process of measurement error control in the production process is necessary to understand the reasons for its formation, and through certain means and measures can be effectively controlled, not only in order to comply with relevant laws and regulations, to protect the interests of consumers, but also to ensure that the enterprise's own interests, to reduce losses and improve economic efficiency.
