JPH01288346A - Method for supplying material to mill - Google Patents

Abstract

PURPOSE:To make a total energy requirement, i.e. a power consumption of a crushing system optimum and also to improve on crushing efficiency and product quality by counting a weight of return material after crushed and classified as a substitution equivalent weight of a newly supplied material and supplying it to a mill again. CONSTITUTION:A return material R after crushed and classified is added to a newly supplied material F and supplied to a mill 1 at a constant rate of summed weight. At that time, the aforementioned return material R is supplied at a rate, wherein its weight is counted as a substitution equivalent (so-called control gain K: 0.2-0.6 in a modern tube mill) weight of the newly supplied material. For example, in case that a constant feed rate T0 is 1,000kg, it is assumed that an actual control gain is 0.6. When the weight of return R weighed by a sensor 9 is 400kg, 760kg of newly supplied material F is weighed out and supplied to the mill together with the return R. It is possible, as a result, to make an electric power consumption optimum and also to improve on crushing efficiency and product quality.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for supplying material to a mill in which, when supplying material to a mill, a material returned after crushing and classification is added to the newly supplied material. Regarding the improvement of

[Prior Art] As a conventional crushing system of this type, there is the following system for controlling appropriate feed of a mill.

(1) A method of measuring the volume of the mill's grinding noise and controlling the feed so that the volume is moderate.

(2) A method of controlling the feed so that the weight of the material to be crushed that is supplied to the mill remains constant.

(3) A method of controlling the feed so that the required power of the mill matches (follows) a preset value.

These methods employ a variable-based PID controller or a controller formed by a combination of these controllers.

For example, as shown in Fig. 2, tube mill 1, classification R
2. In the closed-circuit crushing system for producing cement, which is composed of transportation routes 3, etc., the method (2) above is adopted, but the new feed material F supplied to the tube mill 1 and the crushing classification The weight T including the later returned amount R is controlled to be constant.

T=F+R=constant・・・・・・・・・・・・・・・
(1) [Problems to be Solved by the Invention] However, in the current state of the prior art illustrated above, the consumption of the crushing energy of the tube mill 1, that is, the Even if the weight of the returned material R from the classifier 2 that has been crushed and the newly fed material F is the same, the returned material R is easier to crush, so the total weight T is constant. Even if there is, there will be a difference in the required crushing energy depending on the amount of return R.

For this reason, simply controlling the total supply weight T to be constant does not take into account the ease of crushing the returned portion R, which does not allow for optimization of power consumption in the mill and results in a decrease in crushing efficiency. There is. This also causes variations in the particle size distribution of fine powder (cement) (reducing cement quality).

The present invention was devised to solve the problems of the conventional technology, and is a novel mill that optimizes the total energy required (power consumption) of the grinding system and improves product quality. The purpose is to provide a material supply method.

[Means for Solving the Problems] In order to achieve the above object, the method of supplying material to a mill of the present invention adds the returned material after crushing and classification to the newly supplied material, and feeds the mill with the sum of the weights constant. In this method, the weight of the returned material after the crushing and classification is replaced with the weight of the new feed material, and then fed.

[Operation] With the above configuration, the weight obtained by adding the weight of the returned material, which is replaced by the weight of the new feed material, and the weight of the new feed material, which is newly fed, passes through the mill chamber. If you control it as a constant feed amount,
The energy required for grinding the returned material and the newly supplied material is commensurate with the grinding power consumed in the chamber of the mill, and efficient grinding is carried out.

[Example] Embodiments of the present invention will be described in detail below based on the drawings.

Note that the same reference numerals are used for components common to the conventional one.

FIG. 1 is a circuit diagram of a method of supplying material to a mill according to the present invention.

As shown in the figure, the circuit of this embodiment includes a material meter 4 for weighing the new feed material F brought in, and a conveying path 5 for conveying the new feed material F discharged from the material meter 4 to the tube mill 1. , a supply passage 6 for supplying the material crushed by the tube mill 1 to the classifier 2, a discharge passage 7 for discharging the product from the classifier 2, and the above-mentioned transportation of the returned material R that needs to be crushed again from the classification 1fi2. and a return passage 8 that returns the amount to the passage 5 while being measured.

The instrument 9 provided in the middle of the return passage 8 is classified as R2.
Weigh the amount R returned from the Then, this returned amount R is replaced with the new feed material F to the tube mill 1 (referred to as control gain), and the sum of the returned amount R and the new feed material F is controlled so as to be constant. It has become. This replacement equivalent and feed control to keep the weight constant after the equivalent are performed by a controller (not shown) and are achieved by adjusting the conveyance speed of the conveyor 10 and the like.

Here, the control gain is a constant determined by the crushability (crushing resistance) of the object to be crushed, the characteristics (performance) of the tube mill 1, and the characteristics (performance) of the classifier 2.

Theoretically, it is expressed as U = (k<1>1-. In this case, U is the ratio of the returned amount to the supplied amount supplied to the classifier.

However, since it is very difficult to use this theoretical value in practice, in the present invention, 'ro = F + Ro = F + kR = constant...
... (2) (k<1) shall be controlled in the form.

The control gain is 0.0 in the recent tube mill 1.
It is in the range of 2 to 0.6. Therefore, when starting the operation of the equipment used in this crushing system, it is determined experimentally using the actual equipment on site and used.

Next, a usage example will be explained.

Assume that the control gain k of the actual machine is 0.6 in a case where the constant feed amount T0 is 1,000 kg. Here, if the meter 9 weighs the returned amount of 400 kg, the weight of the new feed material F is 760 kg.
is weighed and supplied to the mill 1 together with the returned amount, thereby optimizing power consumption and improving crushing efficiency.

[Effects of the Invention] In summary, according to the present invention, since the weight of the returned material after crushing and classification is replaced with the weight of the new feed material and supplied, the total energy required for the crushing system, that is, the power consumption is reduced. This makes it possible to optimize crushing efficiency and improve product quality.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a crushing system of a crushing system to which the present invention is adopted, and FIG. 2 is a crushing system diagram illustrating a conventional supply method. In the figure, 1 is the mill, 2 is the classifier, F is the new feed material, and R is the returned material. Figure 2

Claims (1)

[Claims] 1. In a material supply method to a mill in which the returned material after crushing and classification is added to the newly supplied material and the sum of these weights is kept constant and supplied to the mill, the weight of the returned material after crushing and classification is A method of feeding materials to a mill in which the weight of the feed material is replaced by equivalent weight.