AU2017100298B4 - Remote Wash Control for an Abrasive Slurry Blaster - Google Patents

Abstract

A bypass valve operated by a switch adjacent the nozzle of an abrasive slurry blaster allows the blaster to be quickly and easily switched between blast mode in which abrasive slurry is dispensed to wash mode in which water is dispensed.

Description

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Remote Wash Control for an Abrasive Slurry Blaster 2017100298 01 Jun2017

FIELD OF THE INVENTION

[0001] The present invention relates to the control of abrasive slurry blasters. BACKGROUND TO THE INVENTION

[0002] Abrasive slurry blasters, also referred to in the industry as slurry blasters, vapour blasters or wet abrasive blasters, are gaining in popularity over dry abrasive blasters as they do not produce dust at the work site. However the abrasive slurry often builds upon the work piece and in the work area, necessitating some form of wash down to remove the slurry. This is usually required at the completion of a job and often during a job, and may be required several times.

[0003] Most known abrasive blasters facilitate the wash down process by providing a bypass control that cuts of the feed of slurry to the blast hose and replaces it with water. The control is usually in the form of a lever on the blaster control panel. Whilst effective, this is inconvenient for the operator who has to return to the blaster to the blaster whenever they want to switch between blasting and washing down. The operator may be working either a long way from the blaster (80 metres is not uncommon); in a confined space; at a height; or any combination of the preceding, in which case the need to return to the blaster is highly undesirable. This can lead to increased work time or the operator may not bother performing a wash down when they should leading to a substandard blasting job.

[0004] The object of this invention is to provide a remote wash control for an abrasive slurry blaster to alleviate the above problem, or at least provide the public with a useful alternative.

SUMMARY OF THE INVENTION

[0005] In a first aspect the invention provides a remote wash control mechanism for an abrasive slurry blaster feeding slurry from a slurry tank to a remote dispensing nozzle via a slurry hose, the mechanism comprising a bypass valve to feed water instead of slurry to the slurry hose and a bypass switch located adjacent the nozzle for activating the bypass valve.

[0006] Preferably the blaster further comprises a pneumatic dead man circuit and 2 2017100298 15 Mar 2017 the bypass valve and bypass switch are pneumatic components, and the bypass switch switches air from the pneumatic dead man circuit.

[0007] Alternatively the bypass valve and switch are electrical components.

[0008] The control mechanism may be part of a new abrasive slurry blaster or retrofitted to an existing abrasive slurry blaster.

[0009] It should be noted that any one of the aspects mentioned above may include any of the features of any of the other aspects mentioned above and may include any of the features of any of the embodiments described below as appropriate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows.

[0011] Figure 1 shows a simplified schematic of a prior art abrasive slurry blaster.

[0012] Figure 2 shows a simplified schematic of an abrasive slurry blaster incorporating a wash down control according to a first embodiment of the invention.

DRAWING COMPONENTS

[0013] The drawings include the following integers. 10 prior art slurry blaster 12 pump 14 water source 16 compressed air source 20 slurry tank 30 control tap 32 (control tap) lever 40 dead man slurry/water valve 42 dead man air valve 50 hose bundle 52 slurry hose 2017100298 15 Mar 2017 3 54 nozzle 60 dead man switch 62 dead man air supply line 64 dead man air return line 100 slurry blaster (first embodiment) 130 bypass valve 150 hose bundle 170 bypass switch 172 bypass air supply line 174 bypass air return line

DETAILED DESCRIPTION OF THE INVENTION

[0014] The following detailed description of the invention refers to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts. Dimensions of certain parts shown in the drawings may have been modified and/or exaggerated for the purposes of clarity or illustration.

[0015] The present invention provides a control located at the slurry hose nozzle for switching a slurry blaster between ‘blast mode’ in which abrasive slurry is pumped through the slurry hose and ‘wash mode’ in which water is pumped through the slurry hose. In a first embodiment the control is achieved using pneumatics as an air feed is readily available in a typical slurry blaster system. In further embodiments other control mechanisms are used.

[0016] Figure 1 shows a simplified schematic of a prior art abrasive slurry blaster. This will be described in some details as it sets the context for the invention. The schematic has been simplified to remove well known features which would add little to the present discussion such as manifolds, regulators, dose valves, check valves etcetera. The need for and location of such features would be well understood by someone skilled in the art.

[0017] The prior art slurry blaster 10 in essence comprises an air driven water pump 12 that draws water from a water source 14 and pumps it through a slurry tank 20 4 2017100298 15 Mar 2017 and then through slurry hose 52. The pump 12, as all other components, is powered by compressed air from compressed air source 16, typically a petrol driven air compressor. Compressed air is also introduced into the slurry hose via valve 42 to help transport the slurry. A control tap 30 activated by a lever 32 may be used to place the blaster in wash mode in which the water bypasses the slurry tank so that only water and air is sent down the slurry hose. A dead man circuit disables the pump 12 and cuts off the water or slurry output in the event that the dead man switch 60 located on the nozzle 54 is not activated. The dead man circuit is pneumatically activated with an air supply line 62 running in a hose bundle 50 with the slurry hose 52 to the dead man switch 60 and a return air line 64 running back in the hose bundle to control the water pump 12, dead man water/slurry valve 40 and dead man air valve 42.

[0018] Figure 2 shows a simplified schematic of an abrasive slurry blaster 100 according to the present invention and is similar to the prior art blaster 10, but with the addition of a remotely operated bypass circuit to switch the slurry hose output between slurry and wash water. The bypass circuit comprises a bypass valve 130 between the output of the water pump 12 and the control tap 30 to bypass the slurry tank 20 and a bypass switch 170 located adjacent the nozzle 54 to activate the bypass valve 130.

The bypass switch 170 is preferably a mechanically operated pneumatic switch located adjacent the slurry hose nozzle 54 so that it can be operated conveniently by an operator. The bypass switch air supply line 172 is conveniently fed from the dead man air supply line 62. The bypass switch air return line 174 runs back to the blaster 100 in bundle 150 to activate the bypass valve 130. With the bypass circuit in place the blaster operator no longer needs to return to the blaster to switch between blast mode and wash mode, but merely needs to operate the bypass switch located adjacent to the nozzle.

[0019] The bypass circuit as shown in Figure 2 is pneumatically operated as pneumatic controls are typically used in slurry blasters. This allows blasters to be used on sites without electrical power, with all motive force in the blaster being provided by compressed air from an air compressor which is typically driven by a petrol motor.

[0020] In a further embodiment, in which electrical power is available, the bypass circuitry is electrically operated, with the bypass control switch being an electrical switch that controls an electrically operated control valve. Preferably 12 Volt DC signalling is used for safety. 2017100298 15 Mar 2017 5 [0021] The bypass circuit is preferably fitted as part of a new slurry blaster, but can also be readily retrofitted to most existing slurry blasters.

[0022] The reader will now appreciate the present invention which provides a remote wash control for an abrasive slurry blaster thus making the task of abrasive slurry blasting more efficient for the operator [0023] Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus. Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in this field.

[0024] In the present specification and claims (if any), the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers.

Claims (5)

1. A remote wash control mechanism for an abrasive slurry blaster feeding slurry from a slurry tank to a remote dispensing nozzle via a slurry hose, the mechanism comprising a bypass valve to feed water instead of slurry to the slurry hose and a bypass switch located adjacent the nozzle for activating the bypass valve.

2. A control mechanism as in claim 1, wherein the bypass valve and bypass switch are pneumatic components.

3. A control mechanism as in claim 1, wherein the abrasive slurry blaster further comprises a pneumatic dead man circuit and wherein the bypass switches air from the pneumatic dead man circuit.

4. A control mechanism as in claim 1, wherein the bypass valve and switch are electrical components.

5. A control mechanism according to any one of claims 1 to 4, wherein the control mechanism is retrofitted to an abrasive slurry blaster.