JP2567119Y2 - Hose for mortar and concrete pumping - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hose for pressure-feeding mortar / concrete used in a mortar / concrete spraying method, and exhibits excellent wear resistance and transportability especially for high-viscosity mortar / concrete. About what you do.

[0002]

2. Description of the Related Art There are various types of mortar / concrete used in this mortar / concrete spraying method. Highly viscous materials which have been developed in recent years and which do not slip down and do not require a mold are receiving attention. This material is a high-viscosity mortar concrete with a large amount of cement and a minimum amount of water, which is sprayed at high speed with compressed air onto the construction surface to form a very dense and strong construction body. is there.

[0003] This high-viscosity mortar concrete is guided by compressed air by an air compressor or a blowing device connected thereto, and the mortar concrete injected into the blowing device.
The concrete is sent with compressed air through a hose to the lining construction site and is ejected from the tip of the nozzle.

[0004] By the way, high-viscosity mortar concrete pumped through a hose is a material with a large amount of cement and a minimum amount of water, so that the inner surface of the hose decreases due to wear. Therefore, hoses are frequently replaced as consumables.

Conventionally, rubber hoses have been used as this type of hose. This rubber hose is composed of an inner layer of compounded rubber in consideration of wear resistance, a fiber reinforcing layer, and an outer layer of rubber or synthetic resin.

[0006]

However, even with the inner layer of the compounded rubber in consideration of abrasion resistance, there is a problem that the abrasion progresses, and it has to be replaced in a short time, resulting in poor durability. Therefore, when the inner layer is thickened to allow for wear dimensions, the hose becomes thick and heavy, causing a problem in handling. In addition, there is a problem that mortar / concrete easily adheres to the inner layer of the compounded rubber and the transportability is poor due to a short transport distance.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a mortar / concrete hose for feeding a mortar / concrete excellent in durability and transportability.

[0008]

In order to achieve the above-mentioned object, the present invention provides a mortar / concrete pumping hose having an innermost layer and a reinforcing layer. It is molded from thermoplastic polyurethane of JIS hardness A scale 75-95 added with 2 to 2.0 parts by weight, and has a working pressure of 7 kg / cm ² in the lengthwise and circumferential directions of the entire hose including the reinforcing layer. In some cases, it is reduced to 4% or less.

[0009]

The thermoplastic polyurethane constituting the innermost layer is originally excellent in abrasion resistance, has a good balance of strength and elongation, and can add a considerable amount of lubricant. When a lubricant is added, the coefficient of friction on the innermost layer surface is reduced, and wear resistance and transportability are improved. If the amount of the lubricant is less than 0.2 parts by weight, the improvement of the wear resistance is insufficient, and if it exceeds 2.0 parts by weight, the reduction of the wear resistance due to the decrease in strength starts to be noticeable. The effect of the lubricant is based on JIS of thermoplastic polyurethane.
It is observed in a wide range of hardness A scale 75 to 95.

When the length of the entire hose including the reinforcing layer and the elongation in the circumferential direction are set to 4% or less at an operating pressure of 7 kg / cm ² , the innermost layer is hardly stressed when the hose is bent, and the thermoplastic polyurethane is The elastic force does not decrease, and it is hardly damaged even if sand or the like contained in the mortar / concrete being pumped collides with the innermost surface of the bent portion.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the hose of the present invention, and FIG. 2 is a developed view of a partial cross section of the hose.

1 and 2, the hose 1 has a three-layer structure including an inner layer 4 including an innermost layer 2 and an adhesive layer 3, a reinforcing layer 5, and an outer layer 6. Although this three-layer structure itself is a general one, the material used as the innermost layer 2 and the reinforcing layer 5 for reducing the total elongation of the hose to a specific value or less are different from the conventional ones. It has a structure suitable for.

The innermost layer 2 is made of thermoplastic polyurethane. Thermoplastic polyurethane is a kind of thermoplastic elastomer, and exhibits the same mechanical behavior as normal rubber at 50 ° C or lower, but softens and can be molded at 100 ° C or higher. Molding. Polyurethane has excellent mechanical properties such as abrasion resistance, high elongation and flexibility, and has good compatibility with lubricants.

In the hose of the present invention, a large amount of a lubricant of 0.2 to 2 parts by weight is added to the thermoplastic polyurethane of the innermost layer 2 to further reduce the frictional resistance. As the lubricant, carbohydrates C ₁₂ -C _30, fatty acids, esters and synthetic waxes, C ₁₂ -C ₃₀ fatty acid metal soaps, C ₁₂ -C ₃₀ fatty alcohols, those polyhydric alcohols and partial esters generalization is Can be used. In this embodiment, a mixture of a fatty acid amide type and an ester type is used.

The effect of adding a large amount of lubricant to the thermoplastic polyurethane will be described with reference to the graph of FIG. 3 showing the relationship between the amount of lubricant and the amount of wear. The amount of abrasion was measured with an Akron abrasion tester specified in BS903 (British Standard No. 903). The amount of abrasion was measured by pressing a disc-shaped test piece against the friction disc at an angle of 15 ° and a load of 6 pounds, performing 500 preliminary shears and 1000 test shears. As shown in the figure, the wear amount sharply increases in the region where the lubricant is less than 0.2 parts by weight and in the region where it exceeds 2.0 parts by weight. If the amount exceeds 2.0 parts by weight, it is considered that the mechanical properties of the thermoplastic polyurethane deteriorated and the amount of wear increased. In the region of 0.2 to 2.0 parts by weight, the amount of wear is relatively stable and low.

The thermoplastic polyurethane is usually JIS hardness A
Used on scales 75-95. Table 1 shows the effect of the lubricant in this hardness range.

[0017]

[Table 1]

According to Table 1, the lubricant containing 1 part by weight of the lubricant has a considerably smaller amount of abrasion than the pear without lubricant, and the effect of the lubricant is recognized in a wide range of hardness 75 to 95. A thermoplastic polyurethane having a hardness of 95 or more cannot be used for a hose because of lack of flexibility. The wear amount in Table 1 is different from the case of FIG. 3 and is measured by a Taber abrasion machine specified in JIS7311.

Returning to FIGS. 1 and 2, the adhesive layer 3 is the innermost layer 2
This is to ensure the close contact between the reinforcing layer 5 and the reinforcing layer 5. That is, since the innermost layer 2 has a small coefficient of friction, the reinforcing layer 5 cannot be directly adhered to the innermost layer 2. The adhesive layer 3 is made of thermoplastic polyurethane, polyamide or polyester without a lubricant.

In FIG. 1 and FIG. 2, the reinforcing layer 5 has a warp yarn 11 and a first weft yarn 12 and a second weft yarn 13 alternately having a double weave structure. A polyester spun yarn is used for the warp yarn 11, and a nylon monofilament is wound around the first weft yarn 12 in a spiral shape, and is 7 kg / cm.
^At the working pressure of ^2, the lengthwise and circumferential elongation of the hose 1 is 4% or less. The outer layer 6 is provided so that the unevenness of the first weft yarn 12 of the reinforcing layer 5 does not appear on the surface and the outer surface of the hose can be reliably sealed, and for protection from physical damage, and ordinary polyvinyl chloride or the like is used.

Table 2 shows specific examples of the present invention and comparative examples.
This will be described in comparison.

[0022]

[Table 2]

In Table 2, the hose of the present invention is made of thermoplastic polyurethane (JIS A scale hardness 81,2 m).
m thickness, lubricant 1%), an inner layer consisting of an adhesive layer of thermoplastic polyurethane (JIS A scale hardness 70, 0.5 mm thickness, no lubricant), and polyester spun yarn (20 count / 8x2x239 yarns) ) Warp yarn, nylon monofilament (φ2.5mm) and polyester filament yarn (24 pitches per 1500d / 10 × 10cm)
It has the dimensions of a reinforcement layer with a weft double weave structure of alternating weft yarns and an outer layer of polyvinyl chloride (2 mm thick), with an inner diameter of 42 mm, an outer diameter of 57 mm and a weight of 1.5 kg per meter. Comparative Example 1 uses a polyester spun yarn as the warp yarn as in the present invention, but has a 20th count /
The number of warp yarns is reduced to 8 × 2 × 200, the weft driving is also reduced to 21 pitches, and the lengthwise elongation of the entire hose is 5% or more compared to 2.2% of the present invention. Only the differences are the same. The hose of Comparative Example 2 has an inner layer of chloroprene rubber, a reinforcing layer in which vinylon yarn is woven in a tape shape and wound around the inner layer, and an outer layer of chloroprene rubber, and the inner diameter is the same as that of the present invention.
mm, the outer diameter is as large as 62 mm, and the weight is as heavy as 2.2 kg per m.

A durability test was conducted on the above-mentioned invention examples, Comparative Examples 1 and 2, and Comparative Examples 1 and 2. The hose was arranged so as to have one or more bends, mortar and concrete were pumped at 7 kg / cm ² , and the pumping volume (m ³ ) until the innermost layer was damaged and could not be pumped was measured. The pumping volume at the time of mortar pumping is 2000 m ³ or more in the present invention, and although the thickness of the innermost layer is small, it is 10 times that of Comparative Example 2.
It is twice the 00m ^3. In Comparative Example 1, the elongation in the length direction was large, stress was applied to the innermost layer at the bent portion of the hose, and the sand and the like contained in the mortar were easily damaged by collision, and could not be pumped at 300 m ³ . However, when the elongation in the length direction was set to 4% or less in the whole hose, Comparative Example 2
Exhibits the above durability. Also, if the elongation in the circumferential direction exceeds 4%, stress acts on the innermost layer and the innermost layer is easily damaged, so that the elongation in the circumferential direction needs to be 4% or less. It should be noted that the durability of the concrete has been improved similarly to the mortar.

In the transportability test, a distance (m) was measured as to how far the material could be pumped. In the present invention, the distance of the mortar / concrete of the conventional method was twice or more that of the comparative example 2. Mortar concrete with high viscosity can send more than 4 times the distance.

In the height difference test, the height that can be pumped was measured by the height difference (m), and the height of the mortar / concrete according to the present invention is more than twice that of the mortar / concrete according to the present invention. The high-viscosity mortar described above
It can be raised to 13 times or more with concrete. As described above, in the case of high-viscosity mortar concrete with a large amount of cement and a minimum amount of water, the difference appears remarkably as compared with the conventional rubber hose.

[0027]

According to the present invention having the above-described structure, the innermost layer of the hose is JIS containing 0.2 to 2.0 parts by weight of a lubricant.
Molded with a thermoplastic polyurethane of hardness A scale of 75 to 95, the innermost layer has a reduced coefficient of friction and the amount of wear is reduced, so the durability is increased and the thickness is reduced by the increased durability. It is lighter and easier to handle than rubber hoses. Also, the low coefficient of friction of the innermost layer surface makes it difficult for mortar / concrete to adhere, improving the transportability, and by improving the transportability, the transport distance can be greatly extended. In addition, since the lengthwise and circumferential elongation of the entire hose including the reinforcing layer is reduced to 4% or less at a working pressure of 7 kg / cm ² , the innermost layer is less stressed and is less susceptible to tearing or other damage. Durability is not impaired. As a whole, the time required for hose replacement is long, handling is good, and long-distance transfer is possible, and the hose is suitable for spraying work.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a hose of the present invention.

FIG. 2 is a developed view of a partial cross section of the hose.

FIG. 3 is a graph showing a relationship between a lubricant addition amount and a wear amount.

[Explanation of symbols]

 1 Hose 2 Innermost layer 5 Reinforcement layer

Claims (1)

(57) [Scope of request for utility model registration] 1. A hose having an innermost layer and a reinforcing layer, wherein the innermost layer has a lubricant containing 0.2 to 2.0 parts by weight of a lubricant.
It is molded from a thermoplastic polyurethane having an IS hardness of A scale of 75 to 95, and the length of the entire hose including the reinforcing layer and the elongation in the circumferential direction are reduced to 4% or less at a working pressure of 7 kg / cm ^2. A mortar / concrete hose for pumping.