GB2236966A

GB2236966A - Cement sprayer

Info

Publication number: GB2236966A
Application number: GB9021266A
Authority: GB
Inventors: Michael Peter Smith; Francis Lodowic Bartels
Original assignee: Pipeline Induction Heat Ltd
Current assignee: Pipeline Induction Heat Ltd
Priority date: 1989-10-06
Filing date: 1990-10-01
Publication date: 1991-04-24
Anticipated expiration: 2010-10-01
Also published as: GB2236966B; GB9021266D0; GB8922586D0

Abstract

A machine for application to a surface of a fluid cementitious composition comprising a first container in which the composition is made, means 4 enabling the composition to be transferred to a second container provided with a first helical pump 11 for conveying the composition to a second helical pump 12 through a flexible conduit 15 to an applicator wherein the composition discharging from the conduit is converted into particles by a jet of compressed air prior to deposition on to the surface. The pitch of the helix in the first pump is preferably greater than the pitch of the helix in the second pump. <IMAGE>

Description

Cement Sprayer.

This invention relates to a machine for the application of fire proofing materials to surfaces of buildings and other structures, for example, oil and gas production platforms, associated principally but not exclusively with the production of oil and gas.

Safety requirements within the oil and gas industry require that steel structures such as oil and gas production platforms and the buildings contained within these structures shall be protected against high temperatures including flames. Various methods are employed for providing protection including the application of cementitious materials to exposed surfaces which cannot be protected by more convenient means.

Cementitious compositions can be applied in different ways.

However one of the more convenient methods is to convert them into a fluid or semi-fluid preparation which can be applied as a spray to the surface. However although in principle this method is simple to carry out, there are nevertheless a number of difficulties in converting cementitious materials into a satisfactory fluid or semifluid compositions which can be applied evenly and rapidly over the surface. The present invention is directed to a machine which overcomes in large measure the disadvantages of existing machines for both making and applying such compositions.

Accordingly this invention provides a machine for the application to a surface of a fluid cementitious composition comprising a first container in which the composition is made, means enabling the composition to be transferred to a second container provided with a first helical pump for conveying the composition to a second helical pump which second pump urges the composition through a flexible conduit terminating in an applicator wherein the composition discharging from the conduit is converted into particles by a jet of compressed air prior to deposition on to the surface.

This invention is illustrated but not restricted by the following drawings in which; Figure 1 is a front end view taken in vertical section of one preferred form of the machine.

Figure 2 is a side view taken in vertical section of the machine shown in Fig.l.

Figure 3 is a side view taken in vertical section of an applicator forming part of the machine shown in Figs.l & 2.

In these figures the machine shown generally as numeral 1 comprises a mixing bowl 2 provided with mixer paddles 3 which rotate about a horizontal shaft 4. This shaft performs two functions in that the bowl is mounted for tilting on the same shaft. The lower wall of the bowl is curved and the curvature of the wall is preferably similar to that defined by the path of the rotating paddles. The shaft is rotated by pulley 5 driven by a mixer drive air motor 6. Vessel 2 is also provided with a guard 7 and a water meter 8. The guard is secured by hinges-(not shown) to the bowl and it is connected also to a switch which operates so as to cut off the electric supply to the air motor 6 and thereby to stop the motion of the paddles 3 automatically when the guard is hinged back into an open position.This arrangement therefore prevents accidents in the event of an operative opening the guard and inserting his arm into the bowl whilst mixing of the ingredients is taking place.

The bowl is located above a hopper 9 which is also fitted with a guard 10. The lower part of the hopper tapers downwards to an outlet communicating with an Ar chimede an helical pump 11 which conveys material in the hopper to a second helical pump 12. The latter consists of a rotor which incorporates a single helix rotating within a stator formed by a double hollow helix. The pitch of the helix of the Ar chimede an helix pump is substantially greater than the pitch of the helix forming part of the rotor of the second pump. The two pumps 11 & 12 are both mounted coaxially on the same shaft which is driven conveniently by air motor 13. The present arrangement of pumps has been found very satisfactory.However other forms of pumps can be used in which the cementitious composition is conveyed by a helical pump to a delivery pump which also operates on a helical principle and which utlises a helix having a pitch less than that of the first pump. The outlet 14 of pump 12 is connected by a flexible pipe 15 which terminates in an applicator shown in Fig.3. The latter consists of a tubular body 16 provided with an inlet 17 connected to the flexible pipe 15. A plunger 18 having a tapered end 19 is secured movably within the shoulders of the body, the tapered end being located within a similarly tapered part 20 of the body.

A mixing chamber 21, provided with nozzle 22, is located in the forward part of the body 16. The chamber communicates with an inlet 23 for compressed air supplied by an air compressor (not shown) and, through the interior part of the body, with inlet 17 for the material to be applied. The machine is secured to a chassis 24 provided with wheels 25.

In order to operate the machine air motor 6 is switched on and the bowl 2 is positioned with its mouth directed upwards as shown in the drawing. Whilst the paddles 3 are rotating the desired quantities of solid ingredients are added through the open mouth of the bowl and water is introduced through meter 8. When the contents of the bowl have been mixed together thoroughly to form a slurry motor 13 is switched on to bring pumps 11 and 12 into operation.

At the same time the air compressor is switched on resulting in a jet of compressed air being discharged through inlet 23 into chamber 21. Bowl 2 is then tilted downwards until its contents discharge into the hopper 9.

The slurry is then transported by pump 11 to pump 12 from which it is forced through the flexible pipe to the applicator. Plunger 18 is moved either inwards or outwards so as to ensure that the composition discharging from the nozzle is disrupted into particles satisfactorily by the compressed air and the rate of discharge is sufficient to enable rapid treatment of the surface to be effected.

The present machines possesses a number of advantages over existing machines for spraying cementitious compositions in that less power is required and more efficient mixing is achieved. Furthermore there is a markedly smaller tendency for voids to be formed in the flow of material from the hopper to the applicator. As a consequence delivery of the composition to the surface to be treated is much more uniform. Finally the rate of application of the material can be substantially greater than with existing machines.

Claims

1. A machine for the application to a surface of a fluid cementitious composition comprising a first container in which the composition is made, means enabling the composition to be transferred to a second container provided with a first helical pump for conveying the composition to a second helical pump which second pump urges the composition through a flexible conduit terminating in an applicator wherein the composition discharging from the conduit is converted into particles by a stream of compressed air prior to deposition on the surface.

2. A machine according to Claim 1 wherein the two pumps are mounted coaxially.

3. A machine according to Claim 3 wherein the first pump is an Archimedean helical pump.

4. A machine according to either one of Claims 1 and 2 wherein the second pump is comprises a rotor incorporating a helix rotating within a stator formed by a double hollow helix.

5. A machine according to Claim 4 wherein the pitch of the helix in the first pump is greater than the pitch of the rotating helix of the second pump.

6. A machine according to any one of the preceding claims wherein the first container is mounted for rotation in a vertical plane on a shaft positioned above the second container.

7. A machine according to Clause 6 wherein the first container is provided with paddles which rotate about the same shaft as the container.

8. A machine according to Claim 7 wherein the lower wall of the container is curved and the curvature of the wall is similar to the path defined by the path of the paddles when in rotation.

9. A machine according to any one of the preceding claims wherein the applicator is connected to an air compressor.

10. A machine according to any one of the preceding claims when mounted on wheels.

11. Machines for the application of fluid cementitious compositions as hereinbefore described with particular reference to the drawings.