JPS61230041A - Method and instrument for measuring moisture in batcher plant - Google Patents

Abstract

PURPOSE:To make possible the measurement of the moisture content of aggregate, etc. for concrete by sampling partly the aggregate fed out of an aggregate feeding gate, measuring the weight thereof, adding water to the aggregate and measuring the amt. of the water at which the prescribed volume is obtd. CONSTITUTION:The aggregate fed out of the feeding gate 2 of an aggregate tank 1 is sampled by a sampling conveyor 3 and is fed at a prescribed rate into a measuring tank 4 from which the aggregate is thrown into a hopper 8. The weight thereof is measured by a load cell 6. A stop valve 7 of the hopper 8 is then opened to drop the aggregate into a volume measuring tank 10; at the same time, water is sprayed from a water supply line 12. The valve 11 is closed when a level sensor 13 detects the arrival of the water level at the prescribed height. The water is drained from a discharge pipe 16 until the specified volume is attained, then the total weight of the aggregate and water is determined by the load cell 6. The moisture content of the aggregate is calculated from the two weights determined by the load cell 6, the specified volume and the specific weight of the aggregate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method and apparatus for measuring the moisture content of aggregates for concrete in batch plants and the like.

[Conventional technology]

In bacha plants and the like, ready-mixed concrete is prepared by adding aggregate such as sand and gravel to cement, and then adding an appropriate amount of water and kneading it.

Since the strength of hardened concrete is greatly affected by the moisture in fresh concrete, the amount of moisture at the time of cross-conducting must be strictly controlled within a certain range.

However, since the aggregates such as sand and gravel also contain moisture, and these moisture levels fluctuate depending on the weather, season, production area, etc., it is difficult to accurately determine the amount of moisture in these aggregates. Otherwise, the moisture content in fresh concrete cannot be kept within the ideal range.

Therefore, in the past, for example, sand or gravel was collected in a sampling bottle, the water content was dried in a dryer, and the water content in these aggregates was calculated from the difference in weight before and after drying.

[Problem that the invention seeks to solve]

Since the moisture measurement operation is troublesome and time-consuming, it is usually
Measurements are only taken from a portion of the stored aggregate three to four times a day.

Therefore, it has been difficult to prepare ready-mixed concrete with a constant moisture content, since the measured value of a stored aggregate sample and the moisture content of the weighed aggregate are generally different.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention collects a portion of the aggregate cut out from the aggregate cutting gate, measures the weight, adds water to the collected aggregate to a predetermined volume, The water content in the aggregate was determined from the amount of water added. Furthermore, a sampling device is provided for partially taking out the aggregate cut out from the cutting gate, and a discharge valve is provided at the bottom so that the aggregate sent from the sampling device can be stored and discharged, and the total weight can be measured. a measuring tank, a water supply line for supplying water to the measuring tank, and a level sensor provided in the measuring tank for detecting the volume of water supplied from the high aggregate material and the water supply line. A moisture measuring device was constructed.

[For production]

The aggregate cut out from the aggregate cutting gate is arbitrarily sampled by a sampling device, sent into a weighing tank, and its weight is measured.

Next, while discharging the sample aggregate from the hopper into the volume measuring tank, water is injected into the measuring tank through a water supply line to eliminate air contained in the sample aggregate, and the water surface is detected by a level sensor. The amount of the aggregate and water is set to a predetermined volume, and the weight is measured again.

The amount of surface water in the aggregate can be determined by calculation from the weight of the aggregate thus determined, the total weight of the aggregate and water, and the preset total volume of the aggregate and water.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the apparatus of the present invention, in which a sampling conveyor (3) is disposed below a cutout gate (2) at the bottom of a sand or other aggregate tank (1), and the sampling conveyor (3) is The other end of the conveyor (3) is inserted into the upper part of the weighing tank (4) so as not to be in contact with it.

The weighing tank (4) has a cylindrical shape, for example, and is suspended from the frame (5) via a load cell (6).
4) Below the internal sampling conveyor (3),
A capacity measuring tank αO is provided with a hopper (8) having an on-off valve (power) and a discharge valve (9) below the hopper (8).
It is equipped with. Furthermore, in order to supply water to the volume measuring tank αυ, a water supply line az having pulp αυ is inserted into the measuring tank (4) in a non-contact state. A level sensor αJ for detecting the liquid level is provided at a predetermined position.

In the figure, I is the main measuring tank for aggregate, (151 is the discharge gate, (
1G+ indicates a discharge pipe for keeping the liquid level of the capacity measuring tank α [constant].

Aggregate cut out from the cutting gate (2) by the sampling conveyor (3) is arbitrarily sampled, fed in a predetermined amount into the measuring tank (4), placed into the hopper (8), and loaded into the load cell (6).
When the weight of the aggregate is measured and the weight of the weighing tank (4) when the hopper (8) is empty is subtracted from the weight, the weight of the aggregate A (
Kp) is required. The specific gravity of the aggregate is determined in advance,
Let this value be α.

Next, the on-off valve (7) of the hopper (8) is opened to drop the aggregate into the volume measuring tank a1, and at the same time water is injected from the water supply line a2. Furthermore, water is injected even after the aggregate has fallen, and when the level sensor Q31 detects that the water surface has reached a predetermined height, the valve aD is closed, the water injection is stopped, and the discharge pipe ( 161, and keeping the water level constant, measure the total weight with a load cell (6), and subtract the empty weight of the weighing tank (4) from this weight to obtain the total weight C (K19) of aggregate and water. Capacity measurement tank (1
The total volume of aggregate and water in G is V<cr! The level sensor (13) is set so that

Here, if the surface dry weight of the aggregate is B (KP) and the surface water amount of the aggregate is Wrn (Kp), then A =
B + W, . . . The equation (1) holds true. In the formula, β is the specific gravity of water, and β=1.

From this, the surface water amount Wm is calculated as follows: A-W a w, =A+v--c,...-(li>α , and by substituting the above equation (1) into this, it becomes.

The moisture content of the weighed aggregate can be measured by this calculation.

It should be noted that the method and apparatus for measuring moisture in a batcher plant or the like according to the present invention are not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

〔Effect of the invention〕

As explained above, according to the method and apparatus for measuring moisture in a batch plant, etc. of the present invention, various excellent effects as described below are exhibited.

(I) It is possible to accurately measure the amount of water on the surface of aggregates, etc.

(II) Since the measurement operation is easy, the amount of surface water can be measured by sampling the cut aggregate each time it is cut.

0 Since automatic measurement is possible in a short time according to the cutting of aggregate, it is possible to correct the aggregate surface water during measurement.

(IV) According to (1) and (2), optimum ready-mixed concrete can be stably supplied, and concrete quality can always be kept constant.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one embodiment of the apparatus of the present invention. (11 is the aggregate tank, (2) is the cutter), (3) is the sampling conveyor, (4) is the main weighing tank, (6) is the halo cell, (8) is the hopper, αG is the volume measuring tank, a' a indicates a water supply line, (13 indicates a level sensor, and (16) indicates a discharge pipe.

Claims (1)

[Claims] 1) Collect a portion of the aggregate cut out from the aggregate cutting gate, measure its weight, add water to the collected aggregate to a predetermined volume, and A method for measuring moisture in a batch plant or the like, characterized in that the moisture content in the aggregate is determined from the amount of . 2) A sampling device for partially taking out the aggregate cut out from the cutting gate, and a discharge valve at the bottom so that the aggregate sent from the sampling device can be stored and discharged, and the total weight can be measured. a measuring tank, a water supply line for supplying water to the measuring tank, and a level sensor provided in the measuring tank for detecting the volume of the aggregate and water supplied from the water supply line. A moisture measuring device in a batch plant, etc., characterized by the following configuration.