JPH04272015A - Screw type quantitative feeding device - 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]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw type quantitative feeding apparatus among loss-in-weight type quantitative feeding apparatuses.

0002

2. Description of the Related Art A conventional screw-type quantitative feeding device is constructed as shown in FIGS. 2 and 3.

[0003] All the loads of the hopper 1 into which the raw material is charged, the screw feeder 2 that cuts the raw material from the hopper 1, and the drive device 3 of the screw feeder 2 are weighed by a weighing machine (not shown). The drive device 3 is operated so that the amount of weight change per unit time of the weighing machine approaches the target weight value.

[0004] The screw feeder 2 is composed of a first screw 2a and a second screw 2b arranged in parallel, and the first and second screws 2a, 2b are connected to gears 3a, 3b, a chain 4 and 3c, they are driven by a single drive unit 3 in the same direction and at the same speed.

[0005]

[Problems to be Solved by the Invention] In this way, when raw material is cut out from the hopper 1 by the first and second screws 2a and 2b arranged in parallel,
, the pulsation of the raw material to be cut out during one rotation of the second screws 2a, 2b is reduced compared to the case of one screw.

However, in order to increase the flow rate per unit time, large screws are used as the first and second screws 2a and 2b. , 2b are rotated at low speed, there is a problem in that smooth low flow rate dispensing cannot be performed.

An object of the present invention is to provide a screw-type quantitative feeding device that can cut out a large amount of raw material per unit time and can smoothly dispense the raw material at a low flow rate.

[0008]

[Means for Solving the Problems] The screw-type quantitative feeding device of the present invention uses a weighing machine to weigh a hopper, a screw feeder for cutting raw materials from this hopper, and a driving device for the screw feeder, while the unit time of the weighing machine is In the screw-type quantitative feeding device that operates the drive device so that the amount of weight change per unit approaches a target weight value, the screw feeder includes a first screw and a first screw disposed coaxially with the first screw. and a second screw disposed on the outside of the screw, and the drive device includes a first motor that drives the first screw and a second motor that drives the second screw.

[0009]

[Operation] According to this configuration, the first screw is driven by the first motor, and the second screw is driven by the second motor, so in the case of a large flow rate, the first and second screws can be operated simultaneously, or only the larger second screw can be operated and, in the case of small flow rates, the smaller first screw can be operated alone.

Furthermore, when the first and second screws are operated simultaneously, the phase difference between them can be varied to reduce pulsation in the case of a large flow rate.

[0011]

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. Components having the same functions as in FIGS. 2 and 3 showing the conventional example will be described with the same reference numerals.

FIG. 1 shows a screw type constant flow device of the present invention. The first screw 2a that cuts out the raw material from the hopper 1 has a smaller winding diameter than the second screw 2b.
The base end of the screw 2a is fixed to the shaft 5. The shaft 5 is driven by a first motor 8a via a gear 6a, a chain 7, and a gear 6b. The second screw 2b has a larger winding diameter than the first screw 2a.
It is arranged coaxially with the first screw 2a, and its base end is fixed to a coaxial sleeve 9 passed through the shaft 5. The sleeve 9 is driven by a first motor 8b via a gear 10a, a chain 11, and a gear 10b.

The rotational speed of the first motor 8a changes depending on the frequency of the output signal of the first converter 12a. The rotational speed of the second motor 8b is the same as that of the second converter 12.
It changes depending on the frequency of the output signal of b. The frequency of the output signal of the first converter 12a and the second converter 12
The frequency of the output signal b is controlled by the control section 13 as follows.

[0014] The weighing machine 14 includes the hopper 1 and the first,
All loads on the second screws 2a, 2b and the first and second motors 8a, 8b are weighed. Control unit 1
3, if the target flow rate value is larger than the specified value, the first
, the second motors 8a and 8b are rotated simultaneously. Specifically, the frequency of the output signal of the first converter 12a and the frequency of the output signal of the second converter 12b are determined so that the amount of weight change per unit time of the weighing machine 14 approaches the target weight value, and The frequency of the output signal of the first converter 12a or the second converter 12b is modified in accordance with the pulsating component that can be detected from the amount of weight change per unit time of the weighing machine 14, so that the detected pulsating component is reduced. Thus, the phase difference between the first and second screws 2a and 2b is changed.

[0015] When the target flow rate value is smaller than the specified value, only the first motor 8a is rotated. The first one at that time
The frequency of the output signal of the converter 12a is determined according to the magnitude of the target flow rate value.

As described above, when the target flow rate value is larger than the specified value, the first and second screws 2a, 2
b are operated at the same time, and if the target flow rate value is smaller than the specified value, only the first screw 2a with the smaller winding diameter is operated, so the control range is wide and the screw with the larger winding diameter can be rotated at low speed. It is possible to cut out a small stream of raw material extremely smoothly with less pulsation than conventional equipment.

In the above embodiment, when the target flow rate value is larger than the specified value, the first and second motors 8a and 8b are rotated simultaneously, but the second screw 2 with a larger winding diameter
The control unit 13 can also be configured to rotate only a.

[0018] In each of the above-mentioned embodiments, a constant flow metering supply device has been described as an example, but it can be similarly used for a batch type metering supply device. In this case, the first and second motors 8a and 8b may be rotated simultaneously until before quantitative determination, or
Or operate only the second screw 2b to supply a large amount,
When reaching the pre-quantitated amount, only the first screw 2a is operated at low speed to supply a small amount, thereby realizing highly accurate quantitative cutting.

[0019]

As described above, according to the present invention, the screw feeder includes a first screw, a second screw disposed coaxially with the first screw, and disposed outside the first screw. , and a first motor that drives the first screw and a second motor that drives the second screw are installed, making it possible to replace the conventional quantitative feeding device that operates screws of the same size at the same speed. In comparison, a wider control range can be obtained, and in particular, the occurrence of pulsations at low flow rates can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a screw type quantitative feeding device of the present invention.

FIG. 2 is a rear view of the main parts of a conventional screw-type quantitative feeding device.

FIG. 3 is a configuration diagram of a drive system of a conventional screw type quantitative feeding device.

[Explanation of symbols] 1 Hopper 2a First screw 2b Second screw 8a First motor 8b Second motor 12a First converter 12b Second converter 13 Control section 14 Weighing machine

Claims (1)

[Claims] Claim 1: While weighing a hopper, a screw feeder for cutting raw materials from this hopper, and a driving device for the screw feeder using a weighing machine, the driving device is operated so that the amount of weight change per unit time of the weighing machine approaches a target weight value. In the screw type quantitative feeding device that operates the device,
The screw feeder includes a first screw and a second screw arranged coaxially with the first screw and outside the first screw, and the drive device drives the first screw. A screw-type fixed-quantity feeding device that is provided with a first motor and a second motor that drives a second screw.