GB2128504A - Spraying pistol - Google Patents

Abstract

The pistol is particularly suitable for spraying concrete and refractory concrete mixtures, to form a lining on the surface of a furnace wall. The pistol comprises a body (1) accommodating a concrete/water mixer assembly (57) which is fed with concrete and water from respective. hoses (15 and 17). Downstream of the mixer assembly is an axially aligned homogenisation chamber (47) and a discharge nozzle body (46) inclined at from 150 to 60 DEG from the chamber axis. <IMAGE>

Description

SPECIFICATION A spraying pistol The invention relates to a spraying pistol, and more particularly to a pistol for spraying concrete and refractory concrete mixes, including lightweight types thereof.

Pistols for spraying concrete and refractory concrete mixes constitute at present an important part of the equipment for spraying furnace linings and considerably influence the final quality of the lining, especially in terms of homogeneity of the sprayed concrete/water mix, the dustiness of the workplace atmosphere and the loss of material.

A conventional spraying pistol comprises a pistol body to which hoses for supplying, respectively, concrete and water are attached, and which has concrete/water mixing means. Another characteristic feature of such a pistol is a discharge nozzle.

Existing means for clamping, respectively, the end portions of the water and concrete supply hoses to be attached to the spraying pistol body, consists mostly of necks which form integral parts of the pistol body and over which hoses are slid and radially fastened by pin clamps or tapes thereonto.

In some cases, the two hoses are attached to the pistol body by means of threaded sleeves in which they are fixed by bolts passing through the sleeve and hose walls.

It is also known to insert hoses reinforced at the end by a steel coupling, into a rubber socket provided on the spraying pistol body, the two fixing elements being connected to each other as above by boits passing radially therethrough and prevented by clamping tapes from being loosened.

However, all these prior art arrangements hereinabove referred to, suffer from considerable hydraulic losses due to the reduction of their throughflow cross-sectional area, caused by the inserted coupling. Apart from this, the attachment itself is time-consuming and laborious.

With more modern types of spraying pistols, the concrete/water mixing device is made, as a rule, as an annular member having jet holes bored radially therethrough about the entire periphery thereof, the hole axes being oriented to pass through the longitudinal axis of a mixing duct.

Water supplied to such a member forms in this way a system of jets radially entering the flowing mix.

Another system is based upon the principle of immixing water which is supplied through a continuous slit the outlet portion of which is oriented perpendicularly to the longitudinal axis of the concrete-conveying duct.

Unfortunately, all the above-mentioned types of concrete/water mixing means fail to provide for a perfect humidification of the mix to be sprayed, and particularly of the finest components thereof which flow through the mixing duct at the maximum speed. The result is a relatively high dustiness downstream of the discharge pistol nozzle mouth, and consequently a dusty workplace atmosphere as well as a negative influence on material losses and on the final quality of the lining which tends to contain in such cases some components of the original or unmixed material composition, or to contain such components in inadequate mixing ratios.

With conventional spraying pistols, the nozzle body is constituted, as a rule, by a straight tubular part having a uniform inner cross-section along its entire length, or by a tube of conical configuration.

Some types comprise exchangeable, abrasion resistant rubber inserts placed in the nozzle interior.

Disadvantages of the last-mentioned types consist in that some of the material components tend to fall out of the mixture, in a high dustiness, material losses and, finally, in a lower lining quality.

It is an object of the present invention to avoid or at least to mitigate the disadvantages of the prior art as hereinabove set forth and to provide a spraying pistol comprising, according to the invention, a body which accommodates concrete/water mixing means the outlet portion of which is immediately followed, on the one hand, by a tubular portion coaxial with the pistol body and having a homogenization chamber therein, on the other hand, an axially deflected discharge nozzle body having a discharge duct therein.

The concrete/water mixing means may comprise, on the one hand, an external ring provided on its outer periphery with radial apertures for supplying water for mixing, and on its inner periphery with a conical surface, and, on the other hand, an internal ring which is provided on its outer periphery with a recess forming a pressurized chamber, the wall of said ring having a cylindrical part which merges into a conical face to mate with said conical surface of said external ring and forms together with it a discharge gap therebetween.

Between the end portion of said external ring which engages into the recessed portion of said internal ring and confronts the shouldered end portion of the latter, may be arranged a distance ring for regulating the width of the discharge gap, said internal ring being provided on its inner periphery with an abrasion resistant lining.

The axis of the pistol body coincident with that of the tubular portion preferably forms an angle of from 1 50 to 600 with the axis of the discharge nozzle body.

The outlet portion of the discharge nozzle body may carry thereon a sleeve which couples said outlet portion with an extension of the discharge duct of said nozzle body, said extension having in its interior an abrasion resistant insert comprising, in the coupling section, a portion of circular cross section which is followed by a tapered portion and, finally, by a cylindrical outlet portion.

The discharge nozzle body may be provided with a tubular extension which is attached thereto by lock means comprising an annular recess in said extension to accommodate the end portion of the discharge nozzle body, and a threaded coupling socket to hold said two parts together, a bearing face being provided in said recess so as to engage a sectional spring ring received in a peripheral groove, said ring bearing at its opposite side upon a conical face provided on the inner periphery of said coupling socket, a male thread on said coupling socket corresponding to a female thread in said tubular extension.

The homogenization chamber in the coaxial tubular portion of the pistol body is preferably obturated by an axially displaceable plug.

To the end portion of the pistol body opposite the coaxial tubular portion may be attached a concrete supply hose by means of a fastening collet which engages by its inner tapered face one end portion of elastic jaws, said jaws being provided with pins pointing toward the hose so as to engage it, the coupling ring being provided with a male thread to correspond to a female thread in the pistol body.

The pistol body may be provided with a radial hollow handle to which a mix water supply hose is attached, water being supplied to the concrete/water mixing means via a control valve, the mix water supply hose being attached to said valve by spring coupling means in the body of which the hose is received, fixed therein by means of a rubber ring and an insert inserted in said body, and secured in it by a sectional spring ring which is engaged by a conical face of a fastening ring.

The insert may be provided with a male thread to correspond with a female thread in the body of the spring coupling means while said insert is also provided with a female thread to correspond to a male thread on said fastening ring.

By means of the spraying pistol according to the invention, it is possible to reduce many times the dustiness downstream of its discharge nozzle mouth, to substantially reduce material losses and to guarantee the homogeneity of the sprayed coating layer.

The proposed means enable the concrete supply hose as well as the mix water supply hose to be safely, quickly and easily fixed to the pistol body. The attachment eliminates hydraulic losses which usually occur with prior art pistols.

The control of the annular gap for supplying water, and of the depth of the homogenization chamber allows an easy substitution of one material type to be sprayed for another, or, in case of the same material, the change of the binder used. This is of considerable importance when employing the pistol in refractory technique processes where materials having various heatinsulation properties are used for spraying.

The spraying pistol according to the invention provides for perfect wetting of the concrete/water mix and for intensity intermixing thereof before the discharge. The pistol is equipped with a set of quickly and easily interchangeable nozzle heads so that it can be used for many different applications.

A preferred embodiment of a spraying pistol according to the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Fig. 1 is a total sectional view of the pistol; Fig. 1 a is a detail of Fig. 1 showing the attachment of the concrete supply hose to the pistol body; Fig. 2 is a detail sectional view showing the attachment of the mix water supply hose to the pistol body; Fig. 3 is a detail view of the perforated water supply ring; and Fig. 4 is a detail view of an alternative embodiment of the attachment of an extension onto the outlet of the discharge nozzle body.

As can be seen in the drawings, and particularly Fig. 1 thereof, the spraying pistol consists of a tubular pistol body 1 and a handle. The rear portion of the body 1 is provided with a female thread 2, an internal cylindrical surface 3 and a partition 4. In the cavity defined by said cylindrical surface 3, a cylindrical rubber ring 5 is inserted, the portion of which facing the partition 4 is conically bevelled. The cavity of the body 1 accommodates further a jaw ring 6 the part of which opposite the rubber ring 5 is divided into sections so as to form elastic jaws 7 which are provided with radial pins 8. The portion 9 of said jaw ring 6 facing the unbevelled face of said cylindrical rubber ring 5 is compact and bears upon said face.The outer face of said jaws 7 faces the inner side of a fastening collet 10 which has an inner cylindrical surface 11, a sharply tapered surface 12 and a slightly tapered surface 13. The outer cylindrical surface of said collet 10 is provided with a male thread 14 to mate with said female thread 2 in the tubular body 1.

As shown in Fig. 1 and in more detail in Fig. 1a, the rear portion of the pistol body 7 is adapted for being coupled to a material supplying hose 15 in such a manner that when the fastening collet 10 is loosened and when the respective face of the jaws 7 bears on the inner cylindrical surface 11 of said collet 10, the hose 15 can be freely inserted into the pistol body 1 until it abuts said partition 4. By gradually tightening said collet 10, its sharply tapered surface 12 applies a pressure to the flat end portion 16 of said elastic jaws 7, the pressure being transferred through said jaw ring 6 onto the cylindrical rubber ring 5 which becomes compressed and increases its circumference.

Consequently, the material supplying holes 15 is radially packed in the pistol body interior. Due to the action of the sharply tapered surface 12 of said collet 10 bearing on the flat end portion 16 of said jaws 7, the elastic jaws 7, after a critical pressure value has been achieved, are gradually displaced towards the hose surface, until they get into contact with the slightly tapered surface 13 of said collet 10. The latter will thus press the elastic jaws 7 so that they firmly clamp the hose 15, and their pins 8 are forced into the hose wall, thus improving the fastening effect.

As shown in Fig. 1, and in more detail in Fig. 2, the spraying pistol body 1 is supplied with water through a mix water supply hose 1 7 via the pistol handle. The attachment of said hose 17 is made by means of spring coupling means 18, water being caused to pass through a control valve 19.

The coupling means 18 consist of a body 20 having, at its end facing the handle, a female thread 21, an intermediate inner cylindrical surface 22 and an end wall 23 at its end facing the control valve 19. The cavity in the body 20 accommodates a rubber ring 24 which bears by one of its end faces on said end wall 23 while its opposite end face bears on an insert 25 which has a shouldered surface provided with a male thread 26 to mate with said female thread 21 in the body 20 of said spring coupling means 18. In its end portion opposite the rubber ring 24, the insert 25 has a recess provided with a female thread 27 to mate with a male thread on a fastening ring 31 which engages into said recess in the insert 25 and which bears on a sectional spring ring 29 accommodated in said recess and facing a bearing face 28.The fastening ring 31 has a conical face 32 which engages with the sectional spring ring 29.

The hose 17 is attached to said coupling means 18 when the insert 25 and the fastening ring 31 are loosened. The end portion of the base 17 is inserted into the rubber ring 24 until it abuts the end wall 23 of said body 20. By tightening the insert 25 the rubber ring 24 is compressed whereby the thus decreasing cavity in the body 20 is filled so that the end portion of the hose 17 is fixed therein. The sealing is assisted by tightening the fastening ring 31 the conical face 32 of which gradually compresses the sectional spring ring 29 until the hose 17 is perfectly packed in the coupling means 18. Such a mode of attachment is easy, quick and safe.

As can be seen in more detail in Fig. 3, the mix water is supplied further to a reserve chamber 33 provided in the pistol body 1 (see also Fig. 1). The reserve chamber 33 communicates with a concrete/water mixing means 27 formed by two rings, namely an external ring 34, which is provided about its outer periphery with radial apertures 35 and has a conical surface 36, and an internal ring 37, which is provided on its outer periphery with a recess constituting a pressurized chamber 42. The wall of said ring 37 has a cylindrical part which merges into a conical face 38 which together with said conical surface 36 of said external ring 34 define a discharge gap 43 between the two rings 34 and 37. The rings 34 and 37 are separated from each other by a spacer ring 40 which serves for controlling the width of said discharge gap 43.The inner cylindrical surface of said internal ring 37 is provided with an abrasion-resistance lining 41.

The external ring 34 of the mixing means 57 engages a rubber sleeve 44 (Fig. 1) which is designed, by means of a clamping coliet 45, for axially sealing the mixing means 57 and clamping a discharge part of the pistol. The discharge part is bifurcated so that it forms a tubular portion 47 coaxial with the pistol body 1, and an axially deflected discharge nozzle body 46 having a discharge duct therein. The axes of said portion 47 and said body 46 make an angle of from 15O to 600. The tubular portion 47 terminates at a homogenization chamber 49 the outlet of which is obturated by an axially displaceable plug 50.

The outlet portion of the deflected discharge nozzle body 46 carries a sleeve 51 thereon which couples said outlet portion with an extension 54 of the discharge duct by means of respective threaded portions 52 and 53. In its interior, the extension 54 is provided with a system of abrasion-resistant inserts which serves for shaping the outlet cross-section, and comprises for this purpose, in the coupling section, a portion of circular cross-section which is followed by a tapered portion 55 and, finally, by a cylindrical outlet portion 56.

In an alternative embodiment shown in Fig. 4, the discharge nozzle body 46 is provided with a tubular extension 58 which is attached thereto by lock means comprising, on the one hand, an annular recess in said extension 58 to accommodate the end portion of the discharge nozzle body 46, and, on the other hand, a threaded coupling socket 63 to hold said two parts together. In said recess a bearing face 60 is provided so as to engage a sectional spring ring 61 received in a peripheral groove 67. The ring 61 bears at its opposite side upon a conical face 64 provided on the inner periphery of said coupling socket 63. The latter is provided with a male thread 59 to mate with a female thread 65 in said tubular extension 58.

Claims (12)

1. A spraying pistol, more particularly for spraying concrete and refractory concrete mixtures, including lightweight types thereof, the pistol comprising a body which accommodates concrete/water mixing means the outlet portion of which communicates with a discharge part including a tubular portion, which is coaxial with the pistol body and has a homogenization chamber therein, and an axially deflected discharge nozzle body having a discharge duct therein.

2. A spraying pistol according to Claim 1, wherein the mixing means comprise two rings, namely an external ring, provided on its outer periphery with radial apertures for supplying water for mixing, and on its inner periphery with a conical surface, and an internal ring which is provided on its outer periphery with a recess forming a pressurized chamber, the wall of the internal ring having a cylindrical part which merges into a conical face which together with .said conical surface of said external ring define a discharge gap therebetween.

3. A spraying pistol according to Claim 2, wherein a distance ring for controlling the width of the discharge gap is situated between an end portion of said external ring which engages into the recess of said internal ring and confronts the shouldered end portion of the latter, said internal ring being provided on its inner periphery with an abrasion resistant lining.

4. A spraying pistol according to any one of Claims 1 to 3, wherein the axis of the pistol body coincident with that of the tubular portion makes an angle of from 150 to 600 with the axis of the discharge nozzle body.

5. A spraying pistol according to any one of Claims 1 to 4, wherein the outlet portion of the discharge nozzle body carries thereon a sleeve which couples said outlet portion with an extension of a discharge duct in said nozzle body, said extension having in its interior an abrasion resistant insert comprising, in the coupling section, a portion of circular cross-section which is followed by a tapered portion and, finally, by a cylindrical outlet portion.

6. A spraying pistol according to any one of Claims 1 to 4, wherein the discharge nozzle body is provided with a tubular extension which is attached thereto by lock means comprising an annular recess in said extension to accommodate an end portion of the discharge nozzle body, and a threaded coupling socket to hold said two parts together, a bearing face being provided in said recess so as to engage a sectional spring ring received in a peripheral groove, said ring bearing at its opposite side upon a conical face provided on the inner periphery of said coupling socket, and wherein a male thread on said coupling socket engages with a female thread in said tubular extension.

7. A spraying pistol according to any one of Claims 1 to 6, wherein the homogenization chamber in the coaxial tubular portion of the pistol body is obturated by an axially displaceable plug.

8. A spraying pistol according to any one of Claims 1 to 7, wherein to the end portion of the pistol body opposite the coaxial tubular portion is attached a concrete supply hose by means of a fastening collet which engages by its inner tapered face one end portion of elastic jaws, said jaws being provided with pins pointing toward the hose so as to engage it, the fastening collet being provided with a male thread to engage with a female thread in the pistol body.

9. A spraying pistol according to any one of Claims 1 to 8, wherein the pistol body is provided with a radial hol!ow handle to which a mix water supply hose is attached, water being supplied to the mixing means via a control valve, and wherein the mix water supply hose is attached to said valve by spring coupling means having a body in which the hose is received, fixed therein by means of a ring and an insert inserted in said body, and secured in it by a sectional spring ring which is engaged by a conical face of a fastening ring.

10. A spraying pistol as claimed in Claim 9, wherein the insert is provided with a male thread engageable with a female thread in the body of the spring coupling means while said insert is also provided with a female thread engageable with a male thread on said fastening ring.

11. A spraying pistol constructed, arranged and adapted to operate substantially as herein described with reference to, and as shown in, the accompanying drawing.

12. A product made with the use of a spraying pistol according to any one of Claims 1 to 11.