EP0284830A2 - Spraying and mixing nozzle assembly - Google Patents

Abstract

The device which is particularly suitable for concrete dry injections is provided with a dry concrete mixture inlet and a water supply arranged around the latter. A water nozzle ring (12) on which water passages (28) which extend preferably evenly over the annular circumference and essentially radially and are inclined with respect to the annular longitudinal axis are arranged, serves for constantly changing the overall nozzle cross-section (28) for the water directly before it joins the concrete mixture. In this device, the amount of water is controlled by changing the nozzle cross-section directly before the water outlet itself with an essentially constant nozzle jet speed. For this purpose, a hydraulic, manually actuated adjustment device which is very easy to handle and operates on a displacement basis is used. <IMAGE>

Description

The present invention relates to a spray mixing nozzle assembly, in particular for concrete dry spraying, with a mixture inlet and a water supply arranged around it, with means for the current continuous change of the water injection opening cross section during operation, which cross section consists of individual nozzle openings, and with a nozzle designed as a water pressure chamber. Antechamber and a water nozzle ring with water passages.

It is customary in the case of spray mixing nozzle assemblies for the concrete dry mixing to mix the concrete dry mixture conveyed into the assembly with water in this assembly, the water being mixed extensively and normally with a velocity component in the transverse direction of the nozzle with the incoming concrete jet. The correct percentage addition of water to the dry concrete mix is extremely important, so that a corresponding adjustment of the water supply quantity is necessary. Water is normally metered using a through tap in the water line leading to the spray nozzle assembly. This has the disadvantage that when the amount of water is reduced, the water jet speed decreases when it hits the concrete dry jet, or increases when the tap is opened. This behavior leads to uneven, non-homogeneous jet procurement of the wet concrete jet at the outlet end of the nozzle, which is extremely unpleasant when sprayed with concrete.

A mixing nozzle has become known in which the gap width for the water inflow can be adjusted. This design has the fundamental disadvantage that the adjustability is only possible when the nozzle is disassembled and thus it cannot be adapted to the conditions during operation. Furthermore, this ring nozzle basically has the disadvantage that the gap width becomes very small with small amounts of water to be added, which requires precise processing and setting of the ring gap for precise water metering, a condition which can no longer be guaranteed with mixing nozzles in concrete dry spraying machines after some operating time , with which the inflowing amount of water becomes uncontrollable. (DE-A 2 950 117 and DE-A 3 408 007)

The prior art also includes a nozzle of a concrete spraying machine, in which an annular gap is adjusted in its width by adjusting the length of the concrete delivery pipe in a conical intermediate piece, thereby regulating the amount of compressed air added. While such a quantity regulation for the medium air with the help of the annular gap is sufficiently precise, it is completely unsuitable for regulating the addition of water. This nozzle does regulate the compressed air amount possible during operation, but does not bring a usable solution with regard to the admixture of water in the sense of this disclosure. (DE-A 2 622 076)

In contrast, US Pat. No. 2,124,989 shows a solution to a problem that has apparently been pending since 1936, namely the attempt to make individual nozzles that radiate water to the cement jet adjustable in operation by changing the cross section from the outside. A rotating ring with a number of bores is provided, the rotational movement of which changes the inflow cross section of the nozzle bores present in the cement-bearing inner ring. By turning the outer ring, the inflow from the water chamber to the cement jet can either be maximum due to the coincidence of the bores in the rotating ring and the inner ring, or the water supply can be blocked by rotating the ring accordingly. In-depth tests have shown that this, in itself, impressive solution in practice does not allow the expected fine metering of the water to be added for spray mixing nozzle assemblies of the type claimed. It is obvious that a tolerance must be provided between the cement-bearing inner ring and the dosing ring arranged on it so that it rotates, so that it becomes jammed during operation due to impurities or limescale deposits in the water and thus a blocking of the rotating ring on the To prevent pipe ring. However, an annular gap represents a large leak gap with regard to the amount of water to be metered, which makes fine metering impossible and therefore does not meet the practical requirements required today is sufficient. In addition, there is a danger in this embodiment that the water pressure acts on one side of the ring and pushes it away from its position coaxial with the pipe, which also does not ensure a uniform addition of water provided over the pipe cross section, apart from the mechanical adjusting forces acting on the rotating ring, which also try to force the regulating ring out of its coaxial position.

In another known mixing nozzle (DE-A 1 953 777), uniform wetting in an annular nozzle which is adjustable with respect to the gap width - adjustable only in the non-operational state - is to be achieved by mixing the wetted material by deflecting blades. There is a risk that parts of the wetted material will adhere to the walls of the mixing nozzle and in particular to the deflection blades and become stuck there, so that after a relatively short operating time it is necessary to clean the added mixing nozzle, i.e. to interrupt the work process.

A method for mixing dry mixture and water during dry spraying, in particular concrete dry spraying method, has also become known, in which in a mixing tube which is flowed axially by dry mixture, this dry mixture is mixed with air / water mixture flowing transversely to the axial direction from injection channels and mixed. The air and water are premixed before the air / water mixture emerges into the interior of the mixing tube.

This process works with different injection pressures of air and water. These pressures are adjustable by means of adjustable valves for air and water. However, since there is no corresponding pressure chamber which keeps the pressure of the injection water upstream of the channels constant for the entire control range, the condition of constant exit velocity of the water from the injection channels cannot be met either. Therefore, this procedure cannot meet the requirements to be met either. (DE-A 3 220 880)

The present invention aims to provide a spray mixing nozzle assembly, in which the amount of water can be corrected by changing the nozzle cross-section immediately before the water outlet during operation and the simple adaptation to the current conditions is made possible at a substantially constant constant jet speed.

It is essential to create a spray mixing nozzle assembly which allows changing conditions regarding dry concrete mixing during operation, be it quantity per unit of time or composition, at any time by changing the amount of water injected optimally and this exclusively by actuating an adjustment mechanism to change the discharge nozzle cross-section.

The spray mixing nozzle assembly according to the invention achieves this object in that a manually operable regulating device is provided for the hydraulic displacement of a water nozzle cross-sectional change operation.

The invention is subsequently explained, for example, using a drawing.

• Fig. 1 einen Ausschnitt aus einem Spritzmischdüsen­aggregat im Achsialschnitt dargestellt,
• Fig. 2 eine Aufsicht auf die Darstellung nach Fig. 1,
• Fig. 3 einen Schnitt nach Linie III - III der Fig. 1.

Show it:

• 1 shows a detail from a spray mixing nozzle unit in axial section,
• 2 is a plan view of the illustration of FIG. 1,
• 3 shows a section along line III - III of FIG. 1.

A spray mixing nozzle assembly 1 is provided for receiving a concrete supply hose 2. This is inserted into a tube holding sleeve 3 and held there. This sleeve 3 is followed by a so-called gun piece 5, which is connected to the sleeve 3 by means of an all-round weld seam 6.

The pistol piece 5 serves, inter alia, to receive a water nozzle ring 12 and, on the other hand, a metering sleeve 18. Between the nozzle ring 12 and the metering sleeve 18 there is a ring insert 17 in the front part. The corresponding sealing is ensured by O-rings 10, 11, 13 and 14.

A plastic nozzle 16, for example made of Vulcollan, is inserted into the pistol piece 5, its axial holding being done by a corresponding thread in the piece 5. The nozzle ring 12 is in the pistol piece 5 and in the ring insert 17. It is secured against axial displacement forward by an annular stop 22, referred to as a snap ring.

The metering sleeve 18 has a groove-shaped annular space, which is referred to as the water nozzle antechamber 19. It also serves to accommodate an elastic grooved ring 20. As can be seen, this is rotatably, but axially positively guided, arranged in the metering sleeve 18. Such grooved rings 20 are commercially available under the name "Gaco rings".

As can be seen, the water nozzles 28, which are normally arranged substantially uniformly on the circumference of the water nozzle ring 12, are slot-shaped and inclined to the longitudinal axis of the nozzle, running essentially radially, the elevation view of two nozzles being rotated in section. As can also be seen, the metering sleeve 18 is offset with respect to the water nozzle ring 12 in such a way that an annular water passage 29 is formed, through which the water from a water distribution chamber 30 enters the space 19. The chamber 30 is in turn connected via radial bores 23 in the ring insert 17 to an outer ring chamber 24, formed between the pistol piece 5 and the ring insert 17, which in turn is fed with wetting water via the water supply angle nipple 31 becomes. An open / close ball valve is provided that blocks or releases the water flow from the connection nipple. It is operated using a handle on the ball valve (not shown).

At the level of the water supply angle nipple 31 there is also a regulating device 40 which, by means of the actuation of a handwheel 41, enables the entry cross section of the water nozzles 28 to be changed by axially displacing the grooved ring 20.

The regulating device 40 comprises a cylinder jacket 42, one end of which is closed by a welded-on base 44. The other end carries an external thread for receiving a union nut 45 with guide socket 46 for receiving an adjusting spindle 47. The part 49 of the spindle 47 which projects into the interior of the cylinder 48 carries a piston 50. This is by means of a bolt 52 which is in a groove 53 of the cylinder jacket 42 is axially displaceable, but is non-rotatably designed. The adjusting spindle 47 is connected to the piston 50 via a right-hand thread 54. It is rotatable, but axially fixed. The handwheel 41 is attached to its end protruding from the cylinder 50. The two cylinder spaces 56 and 57 are hydraulically separated from one another and outwardly by sealing rings 58, 59 and 61.

Two screw plugs 64 and 65 close two hydraulic fluid refill ports 66 and 67 for the two hydraulically separate systems with the cylinder spaces 56 and 57. From these two spaces 56 and 57, a bore 69 and 70 each leads to an annular space 71 and 72. These spaces 71 and 72 are on both sides of a piston part 74 of the metering sleeve 18, which Rooms 71 and 72 are separated from each other by the O-ring 9.

The regulating device 40 is screwed to the cylinder jacket 42 by means of four screws 75.

The two screw plugs 77 and 78 are used to vent rooms 71 and 72.

The two separate hydraulic systems with rooms 56 and 72 or 57 and 71 always have constant volumes. Hydraulic oil can be used as the liquid.

In operation, the water flow to the nipple 31 is normally fully opened. The grooved ring 20 is in its half-open position (FIGS. 1 and 3), in which the water nozzles 28 are half-open. The piston 50 is in the region of its central position. Now, in order to close the nozzles 28 completely, the handwheel 41 is turned clockwise. The piston 50 moves to the left and presses oil from the space 56 through the bore 70 into the space 72. During the movement of the piston 50, the piston part 74 and with it the dosing sleeve 18 in FIG. 1 are shifted to the left and with it the grooved ring 20, which closes the nozzles 28 more and more.

At the same time, oil will flow from the annular space 71 through the bore 69 into the cylinder space 57 until the handwheel 41 stops.

When the handwheel is turned counterclockwise, the grooved ring 20, which is rotatably arranged in the dosing sleeve 18, is also displaced in the axial direction, so that it now opens the water nozzles 28 with respect to their inlet cross section in accordance with the axial position of the dosing sleeve 18 or the grooved ring 20. By appropriate inclination of these nozzles 28 with respect to the longitudinal axis of the unit and possibly the nozzle cross-section, it is possible to change the nozzle jet cross-section while maintaining the delivery pressure of the added water. This means that the amount of water added can be changed unambiguously and easily and continuously, with the water jet exit velocity remaining essentially the same. In this way it is possible to add the optimum amount of water to different mixtures, be it in terms of composition or amount, and to achieve an essentially constant optimal mixing with the concrete despite the change in this amount of water. Thus, the addition of water as a parameter for the quality of the emerging concrete jet can no longer cause problems when using this spray mixing nozzle unit.

By using the O-ring 11 there is no sealing problem even with this axial displacement and turning process. Furthermore, this possibility of regulation has the great advantage that, in the event of any blockages, a change in the water jet quantity is possible at a constant speed. This allows any nozzle-clogging grains to be removed effortlessly at any time.

It is of course also possible in principle to constructively change the nozzle cross-section of the injection nozzles in a different way than, for example, based on the pure rotary movement of a dosing sleeve, by appropriately removing helical, continuous grooves in the dosing sleeve, but this basically gives the same results leads.

The construction of this unit is very simple in every respect and the screw connections with the simple sealing arrangements allow the unit to be dismantled and reassembled easily and quickly.

The hydraulic regulation is very easy to use and the dosage of the water addition can be optimally adjusted or adjusted.

All the individual parts and individual features shown in the description and / or the figures, as well as their permutations, combinations and variations, are inventive, namely for n individual parts and individual features with the values n = 1 to n → ∞.

Claims (4)

1. Spray mixing nozzle unit, in particular for concrete dry spraying, with a mixture inlet and water supply arranged around it, with means for the current continuous change of the water injection opening cross section during operation, which cross section consists of individual nozzle openings, and with a nozzle pre-chamber designed as a water pressure chamber and one Water nozzle ring (12) with water passages (28), preferably according to at least one of the claims, characterized in that a manually operable regulating device is provided for the hydraulic displacement of a water nozzle cross-section changing member. 2. Unit, preferably according to at least one of the claims, characterized by a rotatably actuated displacement piston in a cylinder jacket with a self-contained hydraulic system provided on both sides of the piston, during the displacement of which a control member is displaced axially for the purpose of changing the slot nozzle cross sections. 3. Unit, preferably according to at least one of the claims, characterized in that the control member comprises an elastic ring with a groove. 4. Unit, preferably according to at least one of the claims, characterized in that the displacement piston is longitudinally guided in the cylinder and it is designed exclusively as a displacement piston.

Images