GB1603636A

GB1603636A - Spraying apparatus

Info

Publication number: GB1603636A
Application number: GB19936/77A
Authority: GB
Original assignee: PYROK SURFACE TREATMENTS Ltd
Current assignee: PYROK SURFACE TREATMENTS Ltd
Priority date: 1978-05-30
Filing date: 1978-05-30
Publication date: 1981-11-25

Description

(54) IMPROVEMENTS RELATING TO SPRAYING APPARATUS (71) We, PYROK (SURFACE TREATMENTS) LIMITED, a British Company of Walrow Highbridge, in the County of Somerset, do hereby declare the invention for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention is concerned with improvements relating to spraying apparatus, and in particular to apparatus for spraying a mixture of aggregate powder and liquid, said apparatus comprising in combination a storage device in which a quantity of the mixture is contained, and a hand-held spray gun comprising an inlet adapted to be connected to an outlet of the storage device by for example a flexible conduit, the storage device comprising feeding means to positively feed the mixture through the outlet along such conduit and to the spray gun.

Apparatus of the kind set out in the last preceding paragraph is hereinafter referred to as "apparatus of the kind specified".

According to the invention there is provided apparatus of the kind specified wherein the spray gun comprises a body defining a chamber, a first inlet through which a mixture of aggregate powder and liquid in the form of a slurry may be fed into the chamber, a second inlet through which air under pressure may be fed into the chamber, an outlet through which a stream of air under pressure may flow from the chamber, upon which stream of air discreet portions of the mixture are entrained, a first control means on the body whereby the rate at which air under pressure is delivered to the chamber may be varied, and a second control means on the body to control operation of the feeding means.

Preferably air is delivered to the chamber through a nozzle located on the longitudinal axis of the chamber, the nozzle facing the outlet. Preferably the nozzle opens into the chamber at a point between the first inlet and the outlet, such that slurry fed into the chamber is extruded around the nozzle and flows into a region of the chamber between the nozzle and the outlet. Preferably the distance between the nozzle and the outlet is adjustable.

Preferably the storage device comprises a first container in which a quantity of the mixture of the aggregate powder and liquid may be contained, and a second container to which aggregate power and liquid may be delivered separately, said second container comprising means to mix the aggregate powder and liquid in said second container, the storage device comprising means to facilitate transfer of the mixture from the second container to the first.

By carrying out the mixing operation in other than the first container, the attainment of a desired consistency (e.g. in the form of a slurry) may be obtained under the control of an operator, before the mixture is transferred to the first container, to be fed therefrom to the spray gun. Additionally, further aggregate powder and liquid may be mixed in said second container without interruption to the feeding of the mixture from the first container to the spray gun.

This enables fine control to be exercised over the total quantity of aggregate powder and liquid produced, in accordance with the actual quantity which will be required, dependent upon the area to be sprayed, or to be finished being sprayed.

Conveniently the second container is open-topped, and desirably the mixing means comprises a paddle mounted for rotation in the container, to mix the aggregate powder and liquid delivered thereto.

Transfer of the mixture may be effected by means of a separate feeding mechanism, but most conveniently the second container is mounted on the first container in a manner whereby the mixture may be tipped from the second container into the first container.

Desirably the feeding means is provided by an elongate feed member provided with a helical formation, preferably said feed member extending from within the first container through the outlet of the storage device, and mechanism to rotate the feed member about its longitudinal axis to cause the mixture to be impelled from the outlet along the flexible conduit towards the spray gun. Preferably a compressed air line extends from the spray gun, by which air under pressure may be fed from the spray gun to the storage device under control of said second control means, said air under pressure controlling operation of the feeding means.

There will now be given a detailed description, to be read with reference to the drawings accompanying the provisional specification of a spraying apparatus which is a preferred embodiment of this invention, and which has been selected to illustrate this invention by way of example.

In the drawings: Figure 1 is a schematic perspective view of a storage device of said apparatus, a mixing container thereof being shown in a full tipping position; Figure 2 is a side elevation of the device shown in Figure 1, the mixing container being shown in a filling position; Figure 3 is an enlarged view of part of the storage device, illustrating a feed member thereof; Figure 4 is a vertical sectional view of a hand held spray gun of said apparatus; and Figure 5 is an inverted plan view of said spray gun.

The apparatus which is the preferred embodiment of this invention is of the kind specified, comprising a storage device (Figure 1, 2 and 3) in which aggregate powder and liquid may be mixed together, and temporarily stored, and a hand held spray gun (Figure 4 and 5) to which such mixture may be fed from the storage device, to be sprayed therefrom onto a surface.

The storage device comprises a wheeled framework 6 supporting a first, storage container 8 in the form of a hopper comprising downwardly-convergent sldes. Secured to a lower end portion of the container 8, and communicating therewith is an outlet chamber 10. An elongate feed member 12 of the storage device, provided with a helical formation 14, extends through said lower end portion into the outlet chamber 10 (see Figure 2). A motor is provided to axially rotate the feed member in a direction such that the helical formation impells material within said lower end portion of the container 8 into the outlet chamber.

A short, hollow cylindrical stem 16, extending from an end plate of the outlet chamber, provides an outlet nozzle through which material impelled by the feed member into the outlet chamber may flow from the outlet chamber.

The storage device also comprises a second, mixing container 20 also in the form of a hopper comprising downwardly convergent walls, and which is mounted in relation to the first container 8 for pivotal movement about a horizontal axis between a filling position (Figure 2) and a closed position (Figure 1). Extending into the mixing chamber 20 is a paddle 22, which affords mixing means of said second container, and which, when the second container is in its open position, is rotated axially by a drive motor 24.

In the use of the storage device, dry aggregate powder and liquid (such as water) are delivered in desired proportions, and in desired quantities, to the container 20 whilst in its fillmg position, and the drive motor 24 operates to rotate the paddle 22, causing the aggregate powder and liquid to be mixed together to a desired consistency. When a desired consistency is attained, the container 20 is lifted about its hinged mounting towards its position, during course of which movement mixture within said container 20 is tipped into the storage container 8. The mixing container 20 is open-topped, and when in its closed position affords a lid to the first container, preventing extraneous material from falling into said container 8.

The spray gun of the spraying apparatus which is the preferred embodiment of this invention comprises a housing 30 defining an inlet chamber 32, a discharge chamber 34 and an air chamber 36, said chambers 34 and 36 being separated by an inwardlydirected annular flange 38, an interior circumferential surface of which is threaded.

Secured to a forward end of the housing 30, so as to extend over a forward open end of the discharge chamber 34 is a discharge nozzle 40, affording an outlet 42, and screwed into a gland 44 at the opposite end of the housing is an end cap 46, said end cap 46 comprising an inwardly directed stem portion 48 provided with a smooth interior axial bore 50.

Extending into the housing 30, through the bore 50, is an air inlet member 52 provided by a hollow elongate stem, a central portion at least of which is threaded on its exterior surface, which portion is in threaded engagement with the circumferential surface of the flange 38.

An axial passage 54 extends through the member 52, opening into the discharge chamber 34 at a forward region thereof. A forward end portion of the member 52, and of the axial passage 54, is flared outwardly, an annular channel 56 being defined between said flared end portion of the inlet member and the cylindrical wall of the discharge chamber.

Provided in the inlet member 52, at that portion which extends across the air chamber 36, is a radial passage 58: a portion of the axial passage 54 rearwardly of said radial passage 58 is threaded, and screwed therein is a control member 60, the position of which may be adjusted axially relative to the inlet member 52 by a control knob 62.

An air inlet is secured to the housing 30, and extends into the air chamber 36, and an air exhaust 66 is also secured to the housing and extends from the air chamber 36, said air exhaust 66 being provided with a control tap 68 (see Figure 5).

In the use of the apparatus which is the preferred embodiment of this invention with the mixing container 20 in its filling position, desired quantities of aggregate powder and liquid are poured into the container, and the paddle 22 is rotated by the drive motor 24 to mix these materials (together with any others which may be desired to be incorporated into the mixture to be sprayed onto the surface being treated). When the mixture in the container 20 reaches a desired consistency, (for example in the form of a free-flowing slurry) the container 20 is lifted towards its closed positions, transferring the mixture from the container 20 to the storage container 8: if desired, the container 20 may be immediately reverted to its filling position, and further constituents mixed to form a further mixture, dependant upon the quantity of mixture required for the job in hand: alternatively, the container 20 may be retained in its closed position, until further mixture is required.

A flexible conduit (not shown) is secured at one end to the stem 16 of the outlet chamber 10 of the storage device, and at the other end to a suitable formation provided on the inlet chamber 32 of the spray gun: the feed member is then rotated axially, to impell mixture from the lower end portion of the storage container along such flexible conduit into the inlet chamber 32 of the spray gun, from which it is forced, as further matenal is impelled thereto, through an inlet 35 opening into the discharge chamber.

Specifically, the inlet 35 opens into the discharge chamber at a region rearwardly of the forward region, at which the axial passage 54 of the air inlet member opens into said discharge chamber.

As further material is delivered to the spray gun, the initially-fed material is forced into the discharge chamber, and forwardly, passing across the annular channel 56 into said forward region of the discharge member.

A supply of compressed air is connected to the air inlet 64, and initially the control tap 68 is maintained closed. When it is desired to spray the mixture of aggregate powder and liquid, the control tap 68 is opened, causing air pressure from chamber 36 to flow to a pressure switch which operates the drive motor to the feed member 12. Compressed air flows into the radial passage 58, into outlet member 52 being controlled by control knob 62 and along the axial passage 54 entering the discharge chamber through the end portion thereof, and flowing from the outlet 42 of the discharge nozzle 40.

As further mixture is forced into the forward region of the discharge chamber, it is picked up on the stream of air flowing through the air inlet member, and is carried on such stream of air through the outlet and from the spray gun.

The spray gun in use is directed towards the surface to be sprayed, and repeated passes of the spray gun over said surface are made, to cause the mixture of aggregate powder and liquid to be applied to said surface, as desired.

At the end of a spraying operation, the control tap 68 is closed, allowing air pressure on the pressure switch to escape and stop the drive motor and any mixture which dribbles from the outlet 42 may be returned to the storage container.

By rotation of the control knob 62, the position of the control member 60 within the axial passage 54 may be varied, and in particular the control member may be moved into a position in which it partially covers the radial passage 58, decreasing the quantity of air which is fed through the axial passage 54. In this manner the speed at which the mixture is impelled from the spray gun towards the surface being sprayed may be varied, as may be required in accordance with the type of mixture being sprayed, and the nature of the prevailing conditions.

A rearward end portion of the air inlet member 52, extending around the control member 60, is provided with an annular control knob 70, by which said inlet member 52 may be rotated, and (by virtue of the threaded engagement with the flange 38) may be finally positioned axially within the discharge chamber 34. By effecting such positional adjustment, the particle size of mixture ejected from the discharge nozzle 40 is varied and hence the texture of the material applied to a substrate is determined.

WHAT WE CLAIM IS: 1. Apparatus of the kind specified wherein the spray gun comprises a body defining a chamber, a first inlet through which a mixture of aggregate powder and liquid in the form of a slurry may be fed into

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. an annular channel 56 being defined between said flared end portion of the inlet member and the cylindrical wall of the discharge chamber. Provided in the inlet member 52, at that portion which extends across the air chamber 36, is a radial passage 58: a portion of the axial passage 54 rearwardly of said radial passage 58 is threaded, and screwed therein is a control member 60, the position of which may be adjusted axially relative to the inlet member 52 by a control knob 62. An air inlet is secured to the housing 30, and extends into the air chamber 36, and an air exhaust 66 is also secured to the housing and extends from the air chamber 36, said air exhaust 66 being provided with a control tap 68 (see Figure 5). In the use of the apparatus which is the preferred embodiment of this invention with the mixing container 20 in its filling position, desired quantities of aggregate powder and liquid are poured into the container, and the paddle 22 is rotated by the drive motor 24 to mix these materials (together with any others which may be desired to be incorporated into the mixture to be sprayed onto the surface being treated). When the mixture in the container 20 reaches a desired consistency, (for example in the form of a free-flowing slurry) the container 20 is lifted towards its closed positions, transferring the mixture from the container 20 to the storage container 8: if desired, the container 20 may be immediately reverted to its filling position, and further constituents mixed to form a further mixture, dependant upon the quantity of mixture required for the job in hand: alternatively, the container 20 may be retained in its closed position, until further mixture is required. A flexible conduit (not shown) is secured at one end to the stem 16 of the outlet chamber 10 of the storage device, and at the other end to a suitable formation provided on the inlet chamber 32 of the spray gun: the feed member is then rotated axially, to impell mixture from the lower end portion of the storage container along such flexible conduit into the inlet chamber 32 of the spray gun, from which it is forced, as further matenal is impelled thereto, through an inlet 35 opening into the discharge chamber. Specifically, the inlet 35 opens into the discharge chamber at a region rearwardly of the forward region, at which the axial passage 54 of the air inlet member opens into said discharge chamber. As further material is delivered to the spray gun, the initially-fed material is forced into the discharge chamber, and forwardly, passing across the annular channel 56 into said forward region of the discharge member. A supply of compressed air is connected to the air inlet 64, and initially the control tap 68 is maintained closed. When it is desired to spray the mixture of aggregate powder and liquid, the control tap 68 is opened, causing air pressure from chamber 36 to flow to a pressure switch which operates the drive motor to the feed member 12. Compressed air flows into the radial passage 58, into outlet member 52 being controlled by control knob 62 and along the axial passage 54 entering the discharge chamber through the end portion thereof, and flowing from the outlet 42 of the discharge nozzle 40. As further mixture is forced into the forward region of the discharge chamber, it is picked up on the stream of air flowing through the air inlet member, and is carried on such stream of air through the outlet and from the spray gun. The spray gun in use is directed towards the surface to be sprayed, and repeated passes of the spray gun over said surface are made, to cause the mixture of aggregate powder and liquid to be applied to said surface, as desired. At the end of a spraying operation, the control tap 68 is closed, allowing air pressure on the pressure switch to escape and stop the drive motor and any mixture which dribbles from the outlet 42 may be returned to the storage container. By rotation of the control knob 62, the position of the control member 60 within the axial passage 54 may be varied, and in particular the control member may be moved into a position in which it partially covers the radial passage 58, decreasing the quantity of air which is fed through the axial passage 54. In this manner the speed at which the mixture is impelled from the spray gun towards the surface being sprayed may be varied, as may be required in accordance with the type of mixture being sprayed, and the nature of the prevailing conditions. A rearward end portion of the air inlet member 52, extending around the control member 60, is provided with an annular control knob 70, by which said inlet member 52 may be rotated, and (by virtue of the threaded engagement with the flange 38) may be finally positioned axially within the discharge chamber 34. By effecting such positional adjustment, the particle size of mixture ejected from the discharge nozzle 40 is varied and hence the texture of the material applied to a substrate is determined. WHAT WE CLAIM IS:

1. Apparatus of the kind specified wherein the spray gun comprises a body defining a chamber, a first inlet through which a mixture of aggregate powder and liquid in the form of a slurry may be fed into

the chamber, a second inlet through which air under pressure may be fed into the chamber, an outlet through which a stream of air under pressure may flow from the chamber, upon which stream of air discreet portions of the mixture are entrained, a first control means on the body whereby the rate at which air under pressure is delivered to the chamber may be varied, and a second control means on the body to control operation of the feeding means.

2. Apparatus according to claim 1 wherein air is delivered to the chamber through a nozzle located on the longitudinal axis of the chamber, the nozzle facing the outlet.

3. Apparatus according to claim 2 wherein the nozzle opens into the chamber at a point between the first inlet and the outlet, such that slurry fed into the chamber is extruded around the nozzle and flows into a region of the chamber between the nozzle and the outlet.

4. Apparatus according to one of claims 2 and 3 wherein the distance between the nozzle and the outlet is adjustable.

5. Apparatus according to any one of the preceding claims, wherein the storage device comprises a first container in which a quantity of the mixture of the aggregate powder and liquid may be contained, and a second container to which aggregate powder and liquid may be delivered separately, said second container comprising means to mix the aggregate powder and liquid in the said second container, the storage device comprising means to facilitate transfer of the mixture from the second container to the first.

6. Apparatus according to claim 5 wherein the second container is opentopped.

7. Apparatus according to claim 6 wherein said mixing means comprises a paddle mounted for rotation in the second container.

8. Apparatus according to any one of claims 5, 6 and 7 wherein the storage device comprises feeding mechanism to transfer the mixture from the second container to the first container.

9. Apparatus according to any one of claims 5, 6 and 7 wherein the second container is mounted on the first container in a manner whereby the mixture may be tipped from the second container into the first.

10. Apparatus according to any one of the preceding claims wherein the feeding means is provided by an elongate feed member provided with a helical formation, and mechanism to rotate the feed member about its longitudinal axis to cause the mixture to be impelled from the outlet along the flexible conduit.

11. Apparatus according to any one of the precedmg claims wherein a compressed air line extends from the spray gun by which air under pressure may be fed from the spray gun to the storage device under control of said second control means, said air under pressure controlling operation of the feeding means.

12. Apparatus of the kind specified, constructed and arranged substantially as hereinbefore described with reference to the drawings accompanying the provisional specification.