JPH0673580U - Pumping tube for placing ready-mixed concrete - Google Patents

Abstract

(57) [Summary] [Purpose] Steel cords cause metal fatigue on both sides of a pumping tube for pouring fresh concrete with a steel cord layer buried therein, which bends repeatedly when used under high pressure conditions. Based on this, the pumping tube is prevented from breaking and its durable life is improved. A steel cord layer (14) is embedded inside a pumping tube (10) mounted on a squeeze type pump except for both side portions which are bent and deformed when the rotor draws the throttle. The pressure-resistant reinforcing layer 18 continuous with the above is buried inside.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a pumping tube for pouring fresh concrete (fresh concrete).

[0002]

[Prior art]

 In the past, ready-mixed concrete was pumped at a construction site by using a piston type pump, a squeeze type pump, etc.

FIG. 3 shows the configuration of a squeeze type pump. In the figure, 100 is a rotor that rotates around a shaft 102, and a rubber roller 106 is rotatably provided at the end of a frame 104. Reference numeral 108 denotes a pumping tube arranged along the semicircular wall 110. As shown in (B), a part of the pumping tube 108 is inside the groove 114 of the rubber pad 112 arranged on the inner surface of the wall 110. It's getting in.

In this squeeze type pump, as the rotor 104 is rotated, the pumping tube 108 is squeezed by the rubber roller 106 to pump the raw concrete inside. At this time, as shown in FIG. 4, the pumping tube 108 repeatedly performs a restoring motion from a circular shape to a flat shape that is completely crushed, and then to a circular shape again. Thus, when the pumping tube 108 is crushed (flat), the pumping tube 108 is in a state of being compressed and elastically deformed by about 26%.

In the pumping tube 108 used in this squeeze type pump, two steel cord layers 202 are laminated between an inner rubber layer 200 and an outer rubber layer 206 as shown in FIG. The steel cord layer 202 is used to secure the required pressure resistance and to prevent stones or the like in the ready-mixed concrete from breaking through the pumping tube 108 when bitten.

In FIG. 5, reference numeral 204 is an intermediate rubber layer, and 208 is an upper cloth layer for preventing the outer rubber layer 206 from peeling off. The upper cloth layer 208 is formed by arranging, for example, 840d / 1 nylon threads at a density of 30 threads / 50 mm so that the threads are oriented in the longitudinal direction of the pumping tube 108, and has no particular reinforcing effect (strong strength). 8 kg / piece).

By the way, the squeeze type pump conventionally feeds and places the raw concrete under a pressure of about 15 to 16 kgf / cm ^{2. In} this case, the life of the pumping tube 108 is about 100 hours.

[0008] where, if altitude hitting設或physician for pumping-pouring the fresh concrete through long pipes (for example, about 100m), the higher pressures, e.g., 20 kgf / cm ² or more, or ready-mixed concrete in 25 kgf / cm ² or more pressure However, the conventional pumping tube 108 cannot withstand use under such harsh conditions, and thus the squeeze pump itself has a pumping ability at high pressure, but the pumping pump 108 cannot pump the pumping tube 108 at a high pressure. The reality is that the life of the tube 108 becomes a bottleneck and this cannot be achieved.

The premature failure of the pumping tube 108, especially when used under high pressure conditions, is due to the cutting of the steel cord layer 202.

As described above, the pumping tube 108 constantly performs the deformation from the circular shape to the flat shape and the restoring movement from the flat shape to the circular shape during the fresh concrete pressure-feeding / placing as shown in FIG. The steel cords in the repeated bending portions on both sides cause metal fatigue at an early stage and are cut, which causes the pumping tube 108 to break.

Incidentally, according to a water circulation test (water pressure test) using a squeeze type pump, under a pressure of 15 kgf / cm ² , the steel cord layer 202 is not cut until the number of repetitions is 100,000, but the pressure is 20 kgf / cm ^2. The steel cord layer 202 is cut at a repetition rate of 10,000 times under a temperature of 25 ° C., and the steel cord layer 202 is cut at a repetition number of 2500 times at a pressure of 25 kgf / cm ² .

In consideration of such metal fatigue, an expensive steel cord having a high fatigue resistance of 3 + 5 × 7 × 0.15 + 1 is used as the steel cord, but as mentioned above, the steel cord is promptly steeled under a high pressure. The code layer 202 is cut and the pumping tube 108 is broken.

[0013]

[Means for Solving the Problems]

 The pumping tube of the present invention was devised to solve such a problem, and its gist is to have an inner rubber layer, an outer rubber layer, and an intermediate steel cord layer, and attach it to a squeeze pump. And a steel cord layer embedded inside the steel cord layer except for both side portions that are bent and deformed during the throttle action by the rotor, and the steel cord layer is The pressure-resistant reinforcing layer is separately embedded inside the steel cord layer so as to be continuous in the circumferential direction on the outer peripheral side.

[0014]

[Action and effect of the device]

 As described above, in the present invention, the conventional steel cord layer was used to prevent the pumping tube from breaking through due to pressure resistance and the trapping of stones, etc. On the other hand, a separate pressure-reinforcing layer is used to ensure the necessary pressure resistance, and the steel cord layer is embedded inside the pumping tube except for the two sides of the pumping tube, which constantly undergoes bending deformation. It is a thing.

According to the present invention, the breaking of the pumping tube due to the metal fatigue of the steel cord layer can be significantly delayed, while the stone embedded layer prevents the trapped stones from penetrating the pumping tube. can do.

In the pumping tube, stones or the like are trapped in an intermediate portion between both sides which are bent and deformed as shown in FIGS. 4 (A) → (B) → (C) and (D). By embedding the steel cord layer excluding the both sides, it is possible to prevent the pumping tube from breaking through due to the stones that have been bitten.

As a result, when the pumping tube is used under high pressure, its durability and life can be significantly improved, and it is also possible to pump and place raw condensate at a high pressure which could not be realized in the past. Become.

Further, according to the present invention, since the steel cord is not required to have high metal fatigue resistance, it is possible to use an inexpensive steel cord that is used as a tire cord, and reduce the cost of the pumping tube. The advantage that can be obtained is also obtained.

[0019]

【Example】

 Next, an embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 1, 10 is a pumping tube having an inner diameter of 135 mmφ and an outer diameter of 174 mmφ, and 12 is an inner rubber layer. Two steel cord layers 14 are laminated on the outer side of the inner rubber layer 12.

The inner rubber layer 12 is made of SBR / NR and has a thickness of 11.0 mm, and the steel cord layer 14 is a steel blind cord used for a tire, that is, a steel cord represented by 7 × 4 × 0.22. Are formed in a comb shape so that they extend obliquely to the longitudinal direction of the pumping tube 10 and are laminated on the outside of the inner rubber layer 12, and the total thickness of the two layers is 4.0 mm. .

Here, the steel cord layer 14 on the inner side and the steel cord layer 14 on the outer side are set such that the inclination directions (bias directions) of the respective steel cords are opposite to each other.

Further, the steel cord layer 14 excludes both side portions that are bent when the pumping tube 10 is crushed and deformed by the rotor of the squeeze type pump, that is, when it is deformed into a flat shape as shown in FIG. Is buried inside the pumping tube 10, and a rubber layer 22 is buried in a portion where the steel cord layer 14 is removed.

In this example, the width w of the rubber layer 22, that is, the width w of the removed portion of the steel cord layer 14 is θ = 10 ° when represented by the central angle θ as shown in FIG. Has been defined. Incidentally, it is desirable that the w has a central angle θ of 5 to 30 °.

An intermediate rubber layer 16 made of SBR is laminated outside the steel cord layer 14 and the rubber layer 22. The intermediate rubber layer 16 is continuous in the circumferential direction and has a thickness of 1.0 mm. On the outside of the intermediate rubber layer 16, a tape-shaped nylon cord layer 17 having a width wider than that of the rubber layer 22 is provided in two layers along the longitudinal direction of the pumping tube 10 at the side portion corresponding to the embedded portion of the rubber layer 22. Two nylon cord layers (pressure-proof reinforcing layers) 18 that are continuous in the circumferential direction are further laminated on the outer side, and an outer rubber layer 20 is laminated on the outer side.

The nylon cord layers 17 and 18 are formed by interlacing 1680 d / 1 × 2 nylon cords in parallel at a density of 41 cords / 50 mm to form a comb shape (strong 29 kg / cord). One provided along the longitudinal direction (in the case of the nylon cord layer 17) outside the intermediate rubber layer 16 so as to be oblique to the longitudinal direction of the pumping tube 10 or wound in the circumferential direction (nylon cord layer). 18). The winding directions of the nylon cords are alternately opposite. These nylon cord layers 17 and 18 have a total thickness of four layers of 2.0 mm. The outer rubber layer 20 is made of SBR and has a thickness of 1.3 mm.

In the pumping tube 10 of the present example, the required pressure resistance is ensured by the pressure resistance reinforcing layer composed of a plurality of nylon cord layers 18, while steel is provided on both sides which are largely bent when subjected to repeated deformation. Since the cord layer 14 is not provided, it is possible to avoid the pumping tube 10 from breaking due to the metal fatigue cutting of the steel cord in the same portion, and the service life is greatly improved.

On the other hand, when a stone or the like is bitten into the pumping tube 10, since the biting portion is an intermediate portion between both bent portions (both sides), the bitten stone or the like is caught. The steel cord layer 14 surely prevents the steel cord layer 14 from penetrating through.

Incidentally, a water circulation test was conducted under a pressure condition of 25 kgf / cm ² by using a squeeze type pump. As a result, the conventional pumping tube 108 shown in FIG. 5 in which the steel cord layer 202 was provided over the entire circumference. In the case of No. 4, the pumping tube 108 burst (broken) after 4.5 hours (the number of repetitions was 2,620 times), but the pumping tube 10 of this example was not abnormal after 40 hours.

In order to confirm the effect of excluding the steel cord layer 14 on both sides, a real machine test (fresh concrete placing test) was performed at 15 kgf / cm ^{2, and} it was found that a burst of stones or the like caused a burst. There was nothing.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention may be configured with other various forms of the pumping tube without departing from the spirit of the present invention. is there.

[Brief description of drawings]

FIG. 1 is a view showing a laminated structure of a pumping tube according to an embodiment of the present invention.

FIG. 2 is a diagram showing a shape of the same pumping tube before and after deformation.

FIG. 3 is a diagram showing a configuration of a squeeze type pump.

FIG. 4 is a diagram showing the shape of the pumping tube in FIG. 3 before and after deformation.

5 is a diagram showing a laminated structure of the pumping tube in FIG.

[Explanation of symbols]

 10 Pumping Tube 12 Inner Rubber Layer 14 Steel Cord Layer 17,18 Nylon Cord Layer 20 Outer Rubber Layer 22 Rubber Layer

Claims (1)

[Scope of utility model registration request] 1. A pumping tube for pouring fresh concrete, which has an inner rubber layer, an outer rubber layer, and a steel cord layer in between, and which is mounted on a squeeze type pump and is subjected to a throttling action by a rotor, wherein the throttle by the rotor is used. The steel cord layer is embedded inside except for both sides that are bent and deformed during operation, and a pressure-proof reinforcing layer is formed inside the steel cord layer separately from the steel cord layer in a circumferentially continuous manner on the outer peripheral side of the steel cord layer. Pumping tube for pouring fresh concrete, which is characterized by being buried in.