DE8110556U1 - DEVICE FOR WET SPRAYING CONCRETE - Google Patents

Description

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Device "for wet spraying of concrete

The present invention relates to a device for wet spraying concrete, with a pumping system for pumpable Concrete followed by a pneumatic transport with a mouth element.

In the wet spray process, there are basically two different types well-known methods, which, however, have not yet made a breakthrough came.

The plug conveying method consists in that the ready-mixed concrete is conveyed by air through pipes or hoses up to Spray nozzle is transported.

This method has the following disadvantages;

Danger of segregation during transport over long distances

no large conveying distances possible, beating conveying hoses, risk of clogging high air consumption at high pressure

high rebound of the concrete on the structure, as the concrete emerges from the nozzle partially separated.

The wet spray flight conveyor method never caught on and is practically no longer used today.

The problems are: limited conveying distance, layer thickness only 2 - 3 cm per spray, insufficient adhesion to the substrate and between the individual sprayed concrete layers, big things

Shrinkage, ultimate strength at approx. 20 N / mm, permeable to water.

In the pumped concrete wet fuel process, the concrete is conveyed through pipes and hoses using a screw or piston concrete pump and then broken up and accelerated at the spray nozzle using compressed air.

This method has the following disadvantages:

The compact concrete column is only broken up at the spray nozzle by the compressed air and meets in lumps the spray surface.

The impact speed is approx. 7 - 12 m / sec. It's way too small.

The compaction on the object is insufficient and does not meet the requirements that are placed on shotcrete.

- The delivery hose is unwieldy because it is too heavy; the whole hose is filled with a compact concrete column up to the nozzle.

The addition of setting accelerators is problematic as it cannot be properly mixed with the concrete.

The application thickness is limited to a few centimeters due to the low compression and adhesion. Over head It is not possible to spray without a snap fastener.

The quality of the shotcrete does not meet the required values, especially in tunnel construction.

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The present invention aims to provide a device for applying quality wet shotcrete, regardless of the conveyor routes.

The device according to the invention, which these conditions fulfilled, is characterized by the wording of the claim

The invention will then be explained using a drawing, for example.

It shows in a purely schematic representation:

1 to 3 three different devices for wet spraying concrete,

Pig. 4 shows an enlarged illustration of a blow-off chamber, partly in longitudinal section,

FIG. 5 shows a plan view of the blow-off chamber according to FIG. 4,

6 shows a meridional section through an acceleration nozzle »

7 shows a detail from a conveyor system with

a blow-off chamber, a downstream acceleration nozzle and a concrete screw conveyor, in the meridional section.

A blow-off chamber 3 is attached to a frame 1. This is provided at the bottom with a concrete connection pipe 4, which concrete pumpable through a concrete pumping line 5 from a concrete pump 20 is supplied. The blow-off chamber 3 is designed in the rear part as a tear-open and mixing part, which is followed by a

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front tapering acceleration position 8 follows. A feed hose 9 is then drawn in, which is in a spray nozzle 11 ends. This has a side connection 12 with a metering device 13, for example for special setting accelerators (Schnellbinder), such as "Sika" or the like, to be supplied from a barrel 21. It has been shown to be extremely effective at least a portion of the additive, in particular quick binder, the compressed air in the line 19, preferably before the To feed metering valve 18, as the lines 22, dash-dotted lines in FIGS. 1 and 2 show. It can accordingly one or both lines 19 in FIG. 3 are acted upon.

The rear part of the blow-off chamber 3 is equipped with a blow nozzle head 15 which blows a number of air nozzles into the opening and mixing part. The compressed air supply takes place from a compressed air line 19 or from a compressor ³ via a metering valve 18.

In a continuous sequence, concrete is pumped into the blow-off chamber 3 through the concrete pumping line 5 and the connecting pipe 4, where this is immediately split up by the powerful air jets from the air nozzles and mixed with the air. The whole is then accelerated in the acceleration part 8 and then transported pneumatically through the conveying hose 9. The ready-to-use mixture is formed at the end of the Blow-off chamber 3 and at the beginning of the hose 3. These parts must be designed structurally and the amount of the pumped mixture as well as the pressure and the amount of conveying air must be coordinated in such a way that in the conveying hose 9 at the latest shortly before entering the Spray nozzle 11 the mixture has the desired speed, namely the speed that it needs .um actually to create a quality wet shotcrete on a part of the building.

FIG. 2 shows a system of basically the same construction, with an acceleration nozzle instead of the blow-off chamber 3 is provided.

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In Fig. 3 a combination of blow-off chamber 3 and downstream acceleration nozzle 23 can be seen, an arrangement that can be used for very special concrete mixes, i

Fig. 4 shows a section from the systems in the sense of FIGS. 1 to 3, in which figure a blow-off chamber 3 in the Cut appears. The concrete is fed through the concrete hose 4 from below, with a round cross-section merges into a rectangular inlet cross-section in the interior of the blow-off chamber 3, as can be seen from FIG. The chamber tapers in the shape of a truncated cone in the direction of flow of the concrete loosened in it by the transport air.

In Fig. 6 is a longitudinal section through a nozzle acceleration § 23 can be seen, inside which a tube-3tück 27 is indicated with a nozzle body 25 and a loading ι ton conveyor connecting nipple 26th Sin flange 29 defines an annular chamber | 30, of which one or more bores 32 leading to the | Central axis of the nozzle body 25 are inclined, open into a mixing chamber 33. Its supply is effected via the compressed air line 19. The mixing chamber 33, the inside ^part: semi-cylindrical and partly frusto-conical trained * det, tapers towards the front and merges into a DUnnstrom conveyor nipple 34 via whose continuation of DUnnstrom-conveying \ hose 9 and then form the spray nozzle 11. ■

j In Fig. 7 is the combination of a blow-off chamber 3 with a |

downstream acceleration nozzle 23 shown, where f the feeding of the concrete through the concrete delivery hose 5

\ takes place in a screw conveyor 40 with a screw 41.

j The screw conveyor 40 is connected by means of a connection piece 42

rectangular cross-section connected to the blow-off chamber 3.

The conveyor 40 is turned by a motor 44 Getriebeeinhelt \

driven and conveys the pumped concrete into the blow-off -. chamber 30, where it is blown through the air from the blow nozzle head 15 experiences a first fluidization with pneumatic transport. >

The stream is then further accelerated by means of the nozzle 23, r

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The devices described allow the starting materials, in particular the concrete, to be transported to the spraying location with the concrete pump from much greater distances, than was previously the case. This mobility is achieved through the combination of the pumping process and the subsequent pneumatic conveying process. This method has i.a. the great advantage that the pneumatic conveying device is made much shorter and is therefore much more mobile with regard to the possibility of setting the injection speed than the previously known systems with long pneumatic transport routes,

The supply of concrete into the blow-off chamber 3 can in this sense, the local conditions and the conditions of the pneumatic Transportes can be adjusted. This, together with the possibility of air regulation with the aid of the metering valve 18, to achieve optimal transport and speed conditions for the concrete mix.

The method described and the devices explained have the following advantages over the previously known ones:

Reaching practically unlimited conveyor routes

High compaction, water impermeability and concrete quality, similar to dry shotcrete

Practically dust-free operation Use of the spray nozzle as with the dry spray process

Flawless quick-binding agent supply into the solid-air mixture

Easy, mobile installation of the concrete injection unit.

Concrete pumping takes place both during pumping and in pneumatic conveying part continuously. It has been shown that the ratio of the cross sections of the pump line 5 and pneumatic line 9 should be in the range of 1: 2, preferably around 1: 1.7, i.e. the line diameter z. B. 38 - 50 or 50: 65 mm.

The blow-off chamber 3 preferably has an elongated hole cross-section, while it has, for example, a semicircular cross-section may have.

The nozzle head 15 is preferably equipped with 8-12 air nozzles for tearing open and accelerating the concrete, while an acceleration nozzle 23 at the blow-off chamber exit three to eight bores 32 are arranged at an angle of approximately to the central axis of the delivery line 9.

The liquid additives through the connection 12 are added at least one meter in front of the mouth of the spray nozzle 11 in order to ensure the desired mixing with the concrete.

It is extremely important to note that the flight promotion at 50 m / sec. and more, e.g. at 60 - 80 m / sec. has to be done.

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summary It is intended to be a device for application

of quality wet shotcrete, regardless of the conveyor lines. In such a device a blow-off chamber (3) is attached to a frame (1). Below is a concrete connection pipe (4) to which a concrete pumping line (5) feeds concrete from a concrete pump (20), intended. The blow-off chamber (3) in the rear part is designed as a tear-open and mixing part and has a tapering acceleration part (3) at the front. This is followed by a Delivery hose (9) ending in a spray nozzle (11). A side connection (12) with dosing device (13) is used to add special setting accelerators (quick binders) from a barrel (21). A blow nozzle head (15) has air nozzles for tearing open and mixing. In a continuous sequence, the concrete pumping line (5) and the connecting pipe (4) Concrete is pumped into the blow-off chamber (3), where it is split up by the air jets and mixed with the air. In the acceleration part (8), the mass is then accelerated pneumatically through the conveying hose 9 transported. The ready-to-spray mixture is formed at the end of the blow-off chamber (3) and at the beginning of the hose (9). In the delivery hose (9), the mixture has the desired speed shortly before entering the spray nozzle (11) at the latest, which it actually needs to achieve a To create quality wet shotcrete on a part of the building.

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Claims (7)

M i.i η c h © u 9 8 t claims 1. Device for wet spraying concrete, with a pump system for pumpable concrete, followed by pneumatic transport with a mouth element, characterized in that a nozzle head with, preferably
eight to twelve, acceleration and tear-off nozzles for
pneumatic transport of the pumpable concrete is provided. 2. Device, preferably according to at least one of the claims, characterized in that the cross-sectional ratio of the pump line and the pneumatic line
is at least 1: 1.5, preferably 1: 1.7. 3. Device, preferably according to at least one of claims, characterized in that the blow-off chamber has a semicircular cross-section with a conical taper
having. 4. Device, preferably according to at least one of claims, characterized in that at the outlet of the Blow-off chamber an acceleration element with three to eight nozzle pipes, which are preferably at an angle of 30 ° to the central axis the conveying line are arranged, is attached. 5. Device, preferably according to at least one of the claims, characterized in that a loosening piece of approx. 3 m length is 1.7 times the cross section of the pump line having. 5.2.82 / ly • t · ■ 6. Device, preferably according to at least one of the Claims, characterized by a delivery line (22) > * for feeding quick ties in front of the chamber (3.23) into the ^ Compressed air line (19). 7. Device, preferably according to at least one of the claims, characterized in that the connection (12) for the liquid additives, especially quick binders, is at least 1 m in front of the nozzle outlet an optimal mixing with the solid-air mixture to secure.