JPS58112901A - Method and device for filling bag with ground material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on a separate IT meter [suspended in the device] that is preset to stop filling material from a certain filling port when a bag attached to a certain filling port reaches a certain volume. The present invention relates to a method and apparatus for filling bags with pulverized material, such as cement, by means of a bag filling machine having a plurality of lowered filling ports.

A bag filling machine of the type described above may be a rotatable automatic machine with filling ports evenly distributed along the circumference and capable of rotating about a vertical axis of the machine. In principle, such a machine works as follows. After the bag is manually or automatically attached to the filling port, a heavy electrical measuring device at the filling port tares the bag, accumulated dust, etc., and then filling of the bag with pulverized material begins.

When the weight measuring device confirms that the inside of the bag has reached the desired weight, supply to the filling port is stopped and the bag is removed. This takes place while the filling port moves along a circumferential path around the axis of the filling machine.

If the filling of the bag is measured as a uniform linear curve, then the heavy electrical measuring device, whether mechanical, electrical or electro-mechanical, will measure when the inside of the bag reaches the desired filling. The filling process will be able to be completed.

However, the successive measurements do not follow a uniform curve because of the dynamic mass forces generated by the filling process, ie the pulverized material flows with force through the filling opening and into the interior of the bag. The end of the filling process therefore rarely takes place when the bag interior reaches the desired loading/mostly when the accounting load of the bag interior weight and dynamic mass forces is equal to the desired shape 1. It is done.

It is known to attenuate fluctuations due to dynamic forces in such a way that the loading of the filled material can be represented on a relatively uniform curve. However, such an increase in attenuation results in a delay of <1llll constant in actual loading.

It is therefore also known to compensate the weighing method for such delays and also for other systematic deviations in the weighing device by weighing filled bags.

Inspection weighing of filled bags is difficult, partly because two filling ports with attached weighing devices do not work exactly the same way, despite having the same structure, and partly because two filling ports with attached weighing devices do not work exactly the same way. Since the material to be filled acts differently at each filling port and at different times during the filling process, this must be done at each filling port at regular intervals.

It is very time-consuming to manually inspect and weigh filled bags in order to correct all settings of the weight measuring device of the filling machine. Automatic test weighing after a run by a filling machine requires all special equipment to control the removal of the individual test weighed bags from the filling port of the filler machine.

It is thus an object of the present invention to devise a method and apparatus which eliminates the above-mentioned disadvantages of known bag filling machines.

According to the present invention, the test weight is measured while the filled bag is suspended from the filling port, and the result of the test weight measurement is immediately used to adjust the settings of the weight measuring device before removing the bag from the filling port. This object is achieved by a method of the type defined in claim 1, characterized in that it is used to.

By weighing the filled bag over the filling port after the filling process has ended and the weighing device has stopped operating, the material inside the bag can be measured statically and thus more accurately. It also makes it possible to make the necessary adjustments to the weighing device without the risk of making incorrect adjustments to the weighing system at the pond filling opening. Furthermore, it is no longer possible to fill a subsequent bag with an incorrect material weight through one filling port before the weighing device has been adjusted.

Bag filling machines equipped with electro-mechanical weighing devices are particularly advantageous for carrying out the method according to the invention, in which case each weighing system weighs according to the actual weight of the bag just filled. Immediately set the preset M setting of the system! It consists of an electro-mechanical weight measuring device characterized by consisting of a regulating load cell, a control unit, a comparison measuring device and a feedback unit.

Compare with bag filling machines where test weighing is done outside the machine and thus requires a special separate weighing device (-
It is an additional advantage of the machine according to the invention that the inspection weighing and related devices are integrated with the heavy electric weighing device and the gravimetric device, respectively.

The invention will be described in more detail below by means of an example of a bag filling machine according to the invention.

Here, Figure M1 is a diagrammatic side view of a part of a rotary bag filling machine equipped with an indication of certain process steps, a weight/time diagram illustrating the system.

FIG. 1 illustrates the movement of the filling spout along the circumferential path during rotation of the bag filling machine. The various travel stages are along the path'
Only the steps shown and of importance to an understanding of the invention are numbered.

In a first step the bags are placed in the filling port, in this example automatically one. Then, during the second and third stages, the bag is tared with a weighing device at the filling port so that the weight of the bag does not affect the measurement of the true weight of the material filled in the bag. The weight is measured.

In the third stage, the filling of the material into the bag begins, and this filling is stopped when the weighing device confirms that the predetermined overlay has been achieved. Filling of the bag is completed at the latest in the fourth stage. Then, in a sixth step, the filled bag is removed, after which the fill port can receive a new empty bag.

In the bag filling machine according to the present invention, a test weight measurement stage 5 is inserted between stages 4 and 6, and the bags filled in this stage 5 are tested and weighed while being suspended from the filling port. At this time, the filling port is stationary and is no longer exposed to dynamic shocks during the filling process.

If the test weight results for both legs deviate from the preset weights, an immediate adjustment of the IT measurement device settings is automatically made.

In FIG. 2, 7 is a rotary material container of a bag filling machine, and the material to be filled into the bags is cement. Reference numeral 8 denotes one filling port among a large number of filling ports evenly arranged around the container 7 and attached along the circumference. As shown, the filling port 8 is coupled to the container 7 via a pipe or hose having a valve 9' and is further clearly connected to a weighing device, illustrated by a load cell 10 on the container 7. It is suspended.

A bag 11 is shown above the filling opening to be filled with a weight of material from the container 7.

In step 1 of FIG. 1, the bag 11 is placed on the filling port 8, and between the second and third stages the tare weight of the bag, accumulated dust, etc. is measured, as shown in FIG. In the third stage, the valve 9 is opened and filling begins.

In FIG. 2, reference numeral 12 is an electro-mechanical setting unit which is set according to a preset weight to be filled inside the bag. Reference numeral 13 denotes a comparison unit 1i111 which continuously receives a signal from the load cell IO during the filling process and compares the signal with the signal from the setting unit 12. The signal from the load cell 10 passes through a damping unit 14 for attenuating fluctuations in the signal caused by the dynamic λ positioning that occurs when discharging material into the interior of the bag 11.

When the comparator confirms that the actual weight of the bag 11 matches the set position on the setting unit 12, a shutoff signal is sent to the valve 9.

Filling is completed at the latest in the fourth stage of FIG. 1, and the heavy electrical measuring method ends its operation between the fourth and fifth stages. In the fifth step, the test weight is measured without affecting the dynamic forces inside the device. Inside the comparator and feedback unit (15) the result of the test weight measurement is compared with a predetermined bag stacking. If the actual heavy electric current inside the bag 11 deviates from the desired value, the setting unit 12 is automatically adjusted through the feedback unit 15 according to the result, and the weight measuring device moves along the circumferential path shown in FIG. The next bag can now be weighed more accurately.

Simply put, this inspection weight measurement method is based on the bag during the filling process.
1. Consists of all essential parts of the heavy electric measurement method for measuring the weight of internal materials.

FIGS. 3 and 4 are lines for 7 hours of overlapping, with the ordinate representing the actual amount of material inside the bag, and the abscissa representing the time, with symbols corresponding to the aforementioned process steps. The dotted horizontal line 16 indicates a preset electric switch that is optically installed inside the bag.

FIG. 3 shows a linear ideal curve 17 of the weight of the material filled inside the bag at any time between the third and fourth stages. If the signal from the load cell 10 follows this curve exactly, the filling can be stopped exactly when the curve 17 reaches or crosses the horizontal line 16, which is very easy to obtain. Dew.

Since the filling process generates a dynamic mass force inside the device, the signal from the load cell 10 is not linear and uniform, but has a strongly undulating curve as shown at 18 in FIG. As a result, the intersection of the horizontal line i16 and the curve 18 does not always coincide with the intersection of the horizontal line 16 and the ideal curve 17, and thus the signal to close the valve 9 is determined when the weight of the material inside the bag reaches the preset weight. It can occur before or after reaching the target. Therefore, bags filled from the same filling port do not contain the same preset M amount.

As a result, as described above and as shown in FIG. 2, the attenuation unit 14 is arranged so that the signal from the load cell 10 to the comparator 13 follows the curve 19 shown in FIG. inserted between. However, as a result of the damping, which is delayed by a time lag t compared to the ideal curve 17, the valve 9 closes late, ie, after the bag has reached the desired weight t+ by a time lag t.

If the time required to fill a bag is the same for each fill port and corresponding weighing system.

By appropriately setting the setting unit 12 it will be possible to compensate for the late closing of the cod pulp 9 and thus to prevent the filling of the bag 11 with an excessive amount of iL.

However, the filling time is not constant, so a computer unit 20 is additionally inserted between the load cell 10 and the comparator 13 after the damping unit) 14. The computer unit determines that the signal received by the comparator 13 does not follow the force curve 19 (FIG. 4) but follows a curve 21 approximating the ideal curve 17 during the filling process before intersecting the horizontal line 16 during the filling process. The program is set to continuously correct the time lag tf in FIG. In this way, filling can be terminated just when a preset weight has been reached.

However, in reality, the back pressure against which the material inside the bag tends to flow out increases with the degree of filling of the bag. As a result, instead of following the ideal curve 17 in the final portion before crossing the horizontal line 16 during filling, a curved portion of the curve is followed, as shown by the dotted line 22 in FIG. This creates the risk that the weight of the material inside the bag will be inaccurate despite the measurements mentioned above.

As previously mentioned, this problem involves test weighing each filled bag on the filling port and adjusting this weighing system to a preset xk within the comparator and feedback unit 15 (FIG. 2). The solution according to the invention is that the comparison result is immediately used for regulating the control unit 12.

[Brief explanation of the drawing]

FIG. 1 Diagram 1 of the circumferential path of the filling spout with indication of the IK stroke stages; FIG. 2 Diagrammatic side view of a part of a rotary bag filling machine with a single filling spout and an attached weighing system; Figures 8 and 4 show the operating system of the $1 weight measurement system.
Time line diagram. 8: Filling port 10: Load cell 11: Bag 12: Control unit 13: Comparison measuring device 14: Attenuation unit 15: Feedback unit 20: Computer unit Patent applicant: F.L. Smith & Co., Ltd. given name)

Claims (1)

[Scope of Claims] L. The bag attached to the filling port is suspended from a separate weighing device that is preset to terminate filling of material from the filling port when a certain overlap is reached. A method of filling bags with pulverized material using a bag filling machine having a large number of filling ports, in which an inspection overlay measurement is performed while the filled bag is suspended above the filling port, and the test weight is measured. Filling a bag with pulverized material by a bag filling machine, characterized in that the result of the foot is used to adjust the settings of a weighing device immediately and before the filled bag is removed from the filling port. how to. 2 having a number of filling ports suspended from a separate weighing device which is preset to terminate the filling of material from the filling ports when the bag attached to the filling port reaches a critical point; There's a bag filling machine. Each weighing device comprises a load cell (10) and a control unit (12) for instantaneously and automatically adjusting a predetermined weight setting state of the weighing device based on the actual weight of the bag just filled. Comparison measuring device (18
) and a feedback unit (15). a Each weight measuring device further includes a damping unit (14) for damping fluctuations in the signal from the load cell (lO) and a computer unit l-( 20) The bag filling machine according to claim 2, characterized by comprising: