JPH09286674A - Lightweight clay roofing tile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the clay tile improved in freezing resistance without causing any frost damage and also improved in mechanical strength by specifying the total porosity ((closed porosity)+(open porosity)) and the porosity ratio ((closed porosity)/(open porosity)) respectively, in a clay tile that is formed by firing a raw material consisting essentially of clay. SOLUTION: This clay tile is formed by using as a clay tile base material, a raw material consisting essentially of clay which has a mineral composition comprising 30 to 40wt.% clayey material, 15 to 25wt.% feldspathic material, 25 to 40wt.% quartzose material and 5 to 10wt.% other minerals, and firing the clay tile base material. In the clay tile, the total porosity and porosity ratio are adjusted to <=20% and >=0.28 respectively. As a result, thickness of the clay tile can be reduced while maintaining its mechanism strength at a level equivalent to that of a conventional clay tile and accordingly, weight of the clay tile can be reduced to a value by >=20% lighter than that of a conventional clay tile.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lightweight clay roof tile obtained by kneading, molding and firing clay as a main raw material.

[0002]

2. Description of the Related Art Conventionally, clay roof tiles are clay mined in the production area,
Original soil containing feldspar, quartz, other minerals, etc.
Alternatively, it is manufactured by mixing several kinds of raw soil, forming a roof tile body, drying and firing it at about 1050 to 1200 ° C.

Further, the general mineral composition of the above-mentioned tile base material is as follows: 30-40% by weight of clay, 15-25% by weight of feldspar, 25-40% by weight of quartz, and 5-10% by weight of others.
And the particle size composition of the tile base material,
Typical Sekishu tile and Mikawa tile base have the levels shown in Fig. 4.

In order to satisfy the respective specified values of JIS-A-5208 for clay roof tiles by the above-mentioned tile base material, the inner thickness is set to about 15 mm and the quality such as mechanical strength and dimensional accuracy is improved. Are satisfied.

Therefore, the weight of the clay roof tile is about 3 k.
As a result of having also g, transportation cost, overload of building structure materials,
Weight reduction is desired in order to reduce handling at the construction site.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a lightweight clay roof tile having improved cold resistance, mechanical strength, and weight reduction of about 20% or more. .

[0007]

In view of the problem of weight reduction based on the above-mentioned conventional technique, the present inventor has focused on the porosity as an element for weight reduction, and as a result of earnest research,
The present invention has been completed by finding that the relationship between the open porosity and the closed porosity in the porosity is an important factor for weight reduction.

That is, by making the ratio of open porosity and closed porosity of the clay tile, which is a fired body, to be a predetermined value or more, it is possible to reduce the weight and at the same time to prevent frost damage and improve cold resistance. The purpose of the present invention is to provide a lightweight clay roof tile to solve the above drawbacks.

In the clay roof tile of the present invention, the total porosity (closed porosity + open porosity) of the fired body obtained by forming the roof tile base using clay as the main raw material and firing it after drying is 20% or less, and the porosity is The (closed porosity / open porosity) is set to 0.28 or more to prevent frost damage, improve cold resistance, and at the same time improve mechanical strength and reduce weight.

Here, the closed porosity in the porosity ratio is [(calcination weight-weight in boiling water) / (weight in boiling water absorption-weight in boiling water)]-[calculation weight / (2.6 x (weight in boiling water-boiled water)] Underwater weight))].

The open porosity is given by [(boiled water absorption weight-calcination weight) / (boiled water absorption weight-boiled water weight)].

The term "calcined weight" refers to the weight when the calcined clay roof tile is placed in an air dryer, the temperature is maintained at about 110 ° C, and after 24 hours or more, it is taken out and allowed to cool to room temperature. Is.

The boiling water absorption weight is the water temperature of the test body of 1
Immerse the whole form in 5 to 20 ° C of clear water so that its upper surface is about 10 cm below the surface of the water, boil for 5 hours, then take it out and immediately put it in clear water of 15 to 20 ° C. The mass is the value when taken out after cooling to room temperature, quickly wiping each surface with a compress, and immediately measuring.

The weight in boiling water is the mass of a test piece that has absorbed water by boiling and is suspended in water.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, as a clay tile manufacturing facility 1 for manufacturing a lightweight clay tile according to the present invention, various raw materials to be blended And a drying device 3 for drying the blended raw material supplied from the feeding device 2.
Pulverizer 4 for finely pulverizing dry blended raw materials supplied from
A granulating device 5 for granulating the pulverized raw material supplied from the pulverizing device 4 into particles, a kneading machine 6 for kneading and extruding the granular raw material supplied from the granulating device 5, and an extrusion molding from the clay kneading machine 6. A cutting machine 7 for cutting the extruded body to be formed, and a molding machine 8 for press-molding the rough land cut by the cutting machine 7 into a roof tile shape.
A drying furnace 9 for drying the tile base material from the molding machine 8, a glazer 10 for applying a glaze to the white background from the drying furnace 9, and a glaze machine 10
And a firing furnace 11 for firing the glazed tile base material.

As the supply device 2, belt conveyors 12, 12a, which are conveying means for conveying various raw materials to the next step, are provided in series, and above the conveying surfaces of the belt conveyors 12, 12a.
Accommodates various raw materials and transfers the raw materials to the belt conveyor 12, 12a ...
Are provided with a plurality of raw material hoppers 13, 13a ...

Further, among the raw material hoppers 13, 13a, ..., The raw material hopper 13 provided at the base end side of the belt conveyors 12, 12a.
As the above, a defective product such as a fired roof tile is accommodated, and a crusher 14 for roughly crushing the defective product is installed on the discharge port side.

As the other raw material hoppers 13a, the raw material containing sedimentary clay which can be used as a raw material for clay roof tiles in a simple manner, and mudstone, shale, which are known as alternative raw materials for clay roof tiles, Kira, which is the waste soil when washing sedimentary rocks such as slate and glass silica sand, and elutriation of frog clay, waste mud from mountain gravel collection and crushed stone, mining slime,
It is used to store casting waste sand, wastewater from wastewater, rivers, dredged soils on the bottom of lakes, porcelain stones, weathered flower stones, small pebbles, clay, silty clay, silt, and gravel silt.

It is also possible to provide a crusher (not shown) for the other raw material hoppers 13a, if necessary, in order to improve the impression efficiency in the drying device 3.

The drying device 3 is a device for drying the mixed raw material while stirring and discharging the mixed raw material. A stirring paddle 16 is provided in the hollow casing 15 placed horizontally, and hot air is blown into the lower side of the hollow casing 15. A ventilation port 17 is provided, a raw material inlet 18 is provided on the upstream side of the hollow casing 15 in the stirring and conveying direction, and a raw material outlet is provided on the downstream side.
19 are provided.

Further, the exhaust gas discharge port containing the removed water is provided at the upper part of the hollow casing 15 on the downstream side in the stirring and conveying direction.
20 is provided, and a dust collector 21 for collecting dust contained in the exhaust gas is connected to the exhaust gas discharge port 20.

A bucket conveyor 22 and a dry raw material hopper 23 are provided between the drying device 3 and the crushing device 4, and the inlet side of the bucket conveyor 22 is a raw material discharge port 19 of the drying device 3.
Is also connected to the outlet side of the dust collector 21.

A belt feeder 24 is provided for connecting the outlet side of the bucket conveyor 22 and the inlet side of the dry raw material hopper 23, and for feeding the dry raw material at the outlet side of the dry raw material hopper 23.

The dry raw material supplied from the belt feeder 24 is fed through the raw material feeding port 25 of the crushing device 4.

The crushing device 4 is a vertical roller mill having a classification function by an air flow, and this vertical roller mill is composed of a lower casing 26 and an upper casing 26a, and rotation control is performed at the center of the lower casing 26. A table 27 is provided, and a plurality of rollers 28, 28a are provided on the crushing table 27 so as to be rotatable and in contact with the surface of the crushing table 27.

The rollers 28 and 28a can be adjusted in pressure applied to the crushing table 27 by a pressurizing means provided by a hydraulic device 29.

Further, the lower casing 26 and the crushing table 27
An air outlet 30 of a ring shape is provided between and, and air is ejected from the air outlet 30, and a classification mechanism 31 is provided above the upper casing 26a. Reference numeral 31 denotes a plurality of blades 3 at predetermined intervals in the circumferential direction via a supporting member 33 below a vertical cylindrical shaft 32 whose rotation is controlled.
4, 34a ... are attached.

A discharge port 35 is provided on the upper side of the upper casing 26a, and the finely ground powder raw material is taken out from the discharge port 35 together with the air discharged.

Further, there is provided a raw material supply chute 36 connected to the raw material charging port 25 for dropping the dry raw material to the central portion of the crushing table 27.

A bag filter 37 is connected to the discharge port 35 of the crushing device 4, and the powder raw material is collected by the bag filter 37.

Further, a rotary feeder 38 is provided on the outlet side of the bag filter 37, and the powder raw material collected by the rotary feeder 38 is supplied to the powder raw material hopper 39 for storing the fine powder raw material.

A screw conveyor 40 and a bucket conveyor 41 are provided as means for transferring the powder raw material provided between the powder raw material hopper 39 and the bag filter 37.

The granulating apparatus 5 is an inclined rotary plate type granulator which continuously supplies water to the powder raw material and rolls and granulates, and is a plate-shaped rotary formed by a circular bottom plate 42 and a peripheral wall 43. Bread container 44
Is fixed to a rotary tilt shaft 46 which is tilted and supported on the body 45 side and whose rotation is controlled.

Next, as a method for producing a lightweight clay roof tile according to the present invention, a raw material hopper 13, 13a for storing various raw materials and other raw materials, and a predetermined mixing ratio on the belt conveyors 12, 12a. Belt conveyor 12, 12
In the process of supplying to a ..., while crushing a lump of several cm or more in the raw material with a crusher 14 etc.,
It is supplied to the drying device 3 in a state in which iron and the like contained in the raw material are removed.

In the drying device 3, the raw material is sequentially fed from the raw material feeding port 18 while hot air is being fed into the hollow casing 15 from the ventilation port 17, and the stirring paddle 16 continuously stirs the raw material from the raw material discharging port 19 continuously. It is discharged as a dry raw material and supplied into the dry raw material hopper 23 via the bucket conveyor 22.

Next, the dry raw material in the dry raw material hopper 23 is crushed through the raw material supply chute 36 of the pulverizer 4 to the crushing table 27.
When a fixed amount is supplied to the central part of the, the dry raw material is extruded to the outside by the centrifugal force of the rotation control grinding table 27, and the roller 2 which is in contact with the surface of the grinding table 27 outside the grinding table 27
It is bitten between 8, 28a and the crushing table 27 and crushed by compression and shearing force.

The pulverized fine powder rises in association with the air flow sent from between the pulverizing table 27 and the lower casing 26, and has a predetermined particle size by the classification mechanism section 31 provided above the upper casing 26a. Items are sent from the outlet 35 to the bag filter 37 and collected.

As the crushing device 4, the classification mechanism section 31
The classifying ability is controlled by the number of rotations and the amount of ventilation, and coarse particles larger than the predetermined particle size cannot be passed between the blades 34, 34a ... It is hit by the blades 34, 34a, hits the inner surface of the upper casing 26a, stalls as it is, and falls downward,
Collected by an appropriate means and supplied again to the crushing table 27, and coarser particles larger than the above move downward against the air flow and are again supplied to the central part of the crushing table 27,
Further, the coarse particles that have fallen between the crushing table 27 and the lower casing 25 are collected by an appropriate means, and the crushing table is again used.
It is dropped and supplied to the center of 27.

Next, the powder raw material collected by the bag filter 37 is screw conveyor 40 and bucket elevator.
It is accommodated in the powder raw material hopper 39 via 41, and the humidity controller from the outlet side of the powder raw material hopper 39 through a weighing machine (not shown).
Supplied to 47.

In the humidity controller 47, in order to facilitate the formation of nuclei at the time of granulation in the next step, water is preliminarily added to the granulating apparatus 5 while being agitated while being wet and agitated.

Next, in the granulating apparatus 5, when the rotation-controlled pan 44 is wetted with fine powder, and water, which is a medium, is supplied by spraying from above, the fine powder is formed as shown in FIG.
Rolling is repeated like the rolling flow A, and the particles grow in granular form.

As the mechanism of such granulation, the fine powder circulates in the outer peripheral orbit of the rolling flow A at the bottom of the pan 44 at first, but gradually moves toward the surface layer as the particle size grows, and the rolling flow A The granules circulate in the inner orbit of the pan, and the granules granulated to a predetermined grain size overflow from the edge of the pan 44 and are discharged as granules.

[0043]

[Examples] Various raw materials were blended by the supply device 2 of the clay manufacturing facility 1, and the amount of clay was 30 to 40% by weight and the quality of feldspar was 15
-25 wt%, quartz 25-40 wt%, others 5-1
The blended raw material having a mineral composition of 0% by weight is dried by the drying device 3, and the dry raw material is crushed by the crushing device 4
To a predetermined particle size by the crushing device 4, that is, particles having a particle size of 44 μm or less are used in Examples 1, 4, and 6.
And those having a thickness of 50 μm or less are used in Examples 3, 8, 10, and 1.
3, 14 and 75 μm or less in Examples 2 and 12,
16, 18, 21 and 100 μm or less as Example 25, 125 μm or less as Examples 5, 7, 9 and 150 μm or less as Examples 19 and 20, 1
Those having a thickness of 76 μm or less are referred to as Examples 11 and 15, and 2000
The one having a thickness of less than or equal to μm was used as Example 17, and after each treatment, it was fired to obtain each example of a crosspiece having a thickness of about 15 mm of 53A type specified in JIS-A-5208.

The firing temperature in the above embodiment is 1
What was baked at 230 ° C. was used in Examples 1, 2, 3, 12, and 1.
No. 7 and those baked at 1200 ° C. in Examples 4 and 5,
6, 7, 8, 9, 11, 15, 16, 18, 19, 20
And those fired at 1170 ° C. in Examples 10, 13,
It was set to 14, 21, and 25.

Further, in order to compare with the above-mentioned embodiment, the thickness of 53A type specified in JIS-A-5208 manufactured with the mineral composition, the particle size composition (Sekishu tile base), and the firing temperature in the prior art is about 50. Example 2 of a sash tile with a length of 15 mm
2,23,24,26 were obtained.

Then, the porosity, the water absorption rate and the mechanical strength were measured, and a frost damage test was conducted. As shown in the results of Tables 1 and 2, the total porosity (closed porosity + open porosity) was obtained. In Examples 1 to 18 in which the porosity was 20% or less and the porosity (closed porosity / open porosity) was 0.28 or more, frost damage did not occur at all.

Further, in Examples 1 to 18, the bending fracture load is 4200 (N) or more on average, which is the average of the bending fracture loads of Comparative Examples 22, 23, 24 and 26. 2700 (N), which is significantly higher than the wall thicknesses of Examples 1 to 9 (15 mm) in Example 22,
The thickness can be reduced to a wall thickness having an average strength of 23, 24, and 26, which is a weight reduction of about 20% or more.

[0048]

[Table 1]

[0049]

[Table 2]

Here, as the frost damage test, 30 test pieces were used.
It is boiled for a minute to absorb water, immediately frozen at -20 ° C for 8 hours, and observed for cracks and peeling. This is repeated 3 times. This frost damage test is defined in JIS-A-5208. Even if the frost damage test does not show the frost damage even after being repeated 25 times, the frost damage occurs even once even if the test is severe.

The 5-hour boiling water absorption is a value obtained by dividing the weight of water boiled and absorbed by the test body for 5 hours by the calcination weight, and the 24-hour water absorption of the test body is 24 hours.
It is a value obtained by dividing the weight of water soaked in water for a period of time and absorbed by water by the weight of firing.

Further, as a bending fracture load test which is mechanical strength, span 2 defined in JIS-A-5208 is used.
00 mm is supported by a steel round bar with a diameter of about 30 mm, the supporting bar is parallel to the entire width of the center of the span, and the load is about 5 kgf / s (49 N / s) uniformly through the steel round bar with a diameter of about 30 mm. It is to be loaded and implemented.

In the test values of bending fracture load in Table 1, those marked with * are those in which bending fracture did not occur even if the value was more than that value.

[0054]

[Effects of the Invention] In summary, the present invention is a clay tile fired with clay as a main material, the total porosity (closed porosity + open porosity) is 20% or less, the porosity (closed porosity / open porosity) Since it was over 0.28, JI of clay roof tiles
Even after a frost damage test under severer conditions than the stipulation of frost damage in the S standard, no frost damage such as cracking or peeling could be confirmed, and a clay roof tile with significantly improved cold resistance could be obtained, and mechanical strength was improved. It is remarkably improved, whereby the wall thickness can be reduced while maintaining the mechanical strength of the conventional clay roof tile, that is, the clay tile whose weight is reduced by about 20% or more can be obtained. The effect is enormous.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a clay roof tile manufacturing facility for a lightweight clay roof tile according to the present invention.

FIG. 2 is a schematic cross-sectional view of a crushing device in the above clay roof tile manufacturing facility.

FIG. 3 is a schematic perspective view of a granulating device in the clay roof tile manufacturing facility.

FIG. 4 is a diagram showing a particle size distribution of conventional clay roof tiles by production area.

[Explanation of symbols]

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[Procedure amendment]

[Submission date] July 5, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

In order to satisfy the respective specified values of JIS-A-5208 for clay roof tiles by the above-mentioned tile base material, the wall thickness is set to about 15 mm and the quality such as mechanical strength and dimensional accuracy is improved. To satisfy.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

It is also possible to provide a crusher (not shown) for the other raw material hoppers 13a, ... To improve the drying efficiency in the drying device 3, if necessary.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunihiko Hiraiwa 1268 Tsunozu-cho, Gotsu-shi, Shimane Prefecture Yoken Co., Ltd.

Claims (1)

[Claims] 1. A clay tile fired with clay as a main raw material has a total porosity (closed porosity + open porosity) of 20%.
Hereinafter, the porosity (closed porosity / open porosity) is 0.2
A lightweight clay roof tile characterized by being made 8 or more.