WO2004110656A1

WO2004110656A1 - Spray gun cleaner

Info

Publication number: WO2004110656A1
Application number: PCT/ZA2004/000017
Authority: WO
Inventors: Etienne Le Roux
Original assignee: Etienne Le Roux
Priority date: 2003-06-13
Filing date: 2004-02-20
Publication date: 2004-12-23

Abstract

Pressurised fluid driven cleaning equipment in the form of a paint application spray gun cleaner (10) comprises a cleaning hopper (12) enclosing a cleaning chamber (14), a heavy duty injection flushing nozzle (16) onto which a spray gun (18) is mountable for interior flushing, an interior and exterior spray gun cleaning liquid washing layout (22) for spray gun secondary cleaning and washing, a pneumatically driven pump (28), an agent vessel (30) and a spent agent collection hopper (38). The hoppers (12, 38) are clo sable against escape of agent fumes during use by way of lids (36, 46) reopenably closing off boxes (34, 44). The equipment is fit ted with fluid flow selction valves (48, 80 and 86). The valve 80 is used for changing the pump (28) from suction to agent ejection, the valve 48 for switching the cleaning process between the nozzle (16) and the layout (22) and the valve (86) for selecting either agent or pressurised air during the cleaning process.

Description

SPRAY GUN CLEANER

(2) BACKGROUND TO THE INVENTION

Paint application spray guns are conventionally manually cleaned. This process poses both a health and environmental risk owing to the volatile and potentially noxious character of the cleaning agent such as thinners. Another danger is found in the fire hazard posed by such conventional way of cleaning. The conventional way of cleaning is also wasteful in that a large volume of agent is required for the cleaning of a single spray gun. It is, amongst others, an object of this invention to address these problems. (3) FIELD OF THE INVENTION

This invention relates to pressurised fluid driven cleaning equipment for and a method of cleaning at least the interior of at least one apparatus, requiring to from time to time be cleaned, by way of a cleaning agent under conditions of reduced if not minimised environmental inclusive of human exposure thereto during at least the performance of the cleaning procedure. Although not so limited the invention finds useful application in the field of cleaning paint application spray guns while it can be usefully applied in amongst others the printing, mechanical, aviation and coach building industries. The equipment is furthermore compatible for using all kinds of solvents, chemical or acids as cleaning agents.

(5) BRIEF DESCRIPTION OF THE DRAWING The invention is now described, by way of example, with reference to the accompanying drawings. In the drawings

Figure 1 diagrammatically shows pressurised fluid driven cleaning equipment in the form of paint application spray gun cleaner in equipment housing side wall removed side elevation,

Figure 2 shows in more detail the cleaning chamber of the cleaner as fitted with injection means in the form of a flushing nozzle and a liquid washing layout inclusive of in dotted broken lines a spray gun as fitted for flushing,

Figure 3 shows the cleaning chamber of figure 2 as rotated through a right angle and inclusive of in dotted broken lines a spray gun as fitted for washing,

Figure 4 shows in sectioned side elevation a washer set of which the washer nozzle is installed to the cleaning chamber once fully assembled while the adapter of the set is removably securable to the normal air supply of a spray gun prior to its positioning for washing within the cleaning chamber,

Figure 5 shows in side elevation injection means in the form of an injection nozzle that is installed to the cleaning chamber once fully assembled via which a spray gun is mountable within the cleaning chamber and that is used for its high pressure flushing,

Figure 6 shows in side elevation a pneumatically driven pressuriser in the form of a pump forming part of the equipment and that is used to pneumatically provide pressured agent for use in cleaning a spray gun,

Figure 7 shows the pump of figure 6 in plan view, and Figure 8 diagrammatically explains the operation of the pump. (5) DETAILED DESCRIPTION OF THE DRAWINGS

Referring to figures 1 to 5 of the drawings pressurised fluid driven cleaning equipment in the form of a paint application spray gun cleaner is generally indicated by reference numeral 10.

The cleaner 10 comprises cleaning chamber defining means in the form of a cleaning hopper 12 enclosing a cleaning chamber 14 and injection means providing a flushing facility in the form of a flushing nozzle 16 for the primary heavy duty flushing of the interior of a spray gun 18 once mounted in the chamber 14, as shown in broken lines in figure 2. The cleaner 10 also comprises a normal duty interior and exterior spray gun cleaning liquid washing layout 22 in the form of a set of washing jets 24 and a secondary apparatus interior washer nozzle 26 forming part of a washer set 27 and that is used for the secondary cleaning and washing of the spray gun 18 mounted as shown in broken lines in figure 3, a pressuriser in the form of a pneumatically operable to-and-fro displaceable multi inline piston layout pump 28 and a batch cleaning agent supply source in the form of an agent vessel 30. The washing jets 24 are suitably strategically arranged within the chamber 14 to promote the extensive outside surface coverage of a spray gun 18 with pressurised cleaning agent once they are selected for the application of exterior cleaning purposes while the washer nozzle 26 is positioned to enable the mounting of the spray gun 18 there onto in its upright condition, as shown in broken lines in figure 3, for the simultaneous normal cycle internal washing of the spray gun 18 during its process of outside cleaning. Referring more particularly to figure 4 the washer set 27 is constituted from the washer nozzle 26 that is installed to the cleaning chamber 12 on assembly of the washer 10 and an adapter 32 that is removably securable to the normal air supply of a spray gun 18 prior to its positioning for secondary washing. Referring more in particular to figure 5 the nozzle 16 is of narrowing stepped design towards its agent-ejecting end 16.1 to accommodate a variety of spray gun mounting apertures.

To limit agent or fumes from being released into the environment inclusive of exposing the operator of the cleaner 10 thereto, the hopper 12 is at its overhead side closed off by a hopper box 34 that opens up into the chamber 14. The interior of the box 34 is accessible via a lid 36 sealably closing onto the bottom part of the box 34. The outlet 12.1 from the hopper 12 connects to a collection layout in the form of a collection hopper 38 that in turn discharges to a collection vessel 40 into which spent agent is collectible for further use or re- treatment and/or recycling. The outlet from the hopper 38 is fitted with a drain cock 42 used for draining spent agent into the vessel 40.

The cleaner 10 also incorporates a pre-wash facility in the form of a pre-wash box 44 opening up into the collection hopper 38. As with the box 34, the pre-wash box 44 is also fitted with a sealing lid 46 to ensure that the interior of the hoppers 12, 38 are closed off from the environment once the cleaner 10 is used for injection or exterior washing of a spray gun 18 mounted in the cleaning hopper 12. The pre-wash box 44 is naturally open when used for manual spray gun pre-washing.

While not shown the cleaner 10 naturally incorporates appropriate piping to carry agent from the pump 28 to either the flushing nozzle 16 or the cleaning layout 22 inclusive of the nozzle 26. Switching of agent between the nozzle 16 and the layout 22 is achieved via a fluid flow selection valve 48. The various elements of the cleaner 10 are suitably secured and mounted within a housing 50.

While particularly referring to figure 2 the nozzle 16 is mounted to the conical bottom end side wall of the hopper 12 with its ejection end 16.1 facing inward and upward to promote the mounting of a spray gun in its upside down position there onto. When so mounted the ejection end 16.1 of the nozzle 16 registers with the inlet mouth of the spray gun 18 to promote exposure of its interior to heavy duty interior flushing. The nozzle 16 thus provides the full support for maintaining the spray gun 18 in its heavy duty cleaning position once ready to be operatively used while loss of cleaning agent directly to the hopper 12 is limited by the stepped engaging configuration of the nozzle 16.

In referring more particularly to figure 3 the washer nozzle 26 is also mounted to the conical bottom of the hopper 12. It thus engages against leakage with the spray gun 18 via the adapter 32 during the washing cycle of the cleaner 10. The nozzle 26 is situated along the agent supply tubing 52 that supplies both the nozzle 26 and the jets 24 to cause their simultaneous operation.

In more particular referring to figures 1 and 6 to 8 the pump 28, as pneumatically, operable is couplable via a coupling 54 to a source of pneumatic pressure for operation of the cleaner 10. The pump 28 is fitted with a piston layout 56 that to-and-from displaceably fits a cylinder configuration 58. The configuration 58 is constituted from three cylinders 60 along each of which a piston 62 is displaceable. The pistons 62 are centrally interconnected by shafts 64 extending against fluid leakage through apertures though cylinder end blocks 66. The pump 28 incorporated two end blocks 66.1 and 66.2 and two intermediate blocks 66.3 and 66.4. The blocks 66 are formed with internal passages (not shown) to the effect of appropriately directing pressurised air via air passage tubes 68 for urging the pistons 62 the one way or the other.

As shown in figures 8(a) to 8(c), as matching the figure 6 view, on commencement of the charging stroke of the pump 28 for becoming charged with cleaning agent, compressed air is directed to flow via a connection 70 along the branched tubing 68.1 and though the blocks 66.3 and 66.4 into the cylinders 60.2 and 60.3. The pistons 62 are thus urged to become displaced in the direction of arrow 72. Figures 8(b) and 8(c) show the movement of the pistons 62 along the suction stroke of the pump 28. Air found in the cylinders 60 situated on the opposite sides of the pistons 62 is exhausted via the branched tubing 68.2 and the connection 74 as appropriately connected downstream to permit such exhaustion. During the suction stroke liquid agent is drawn into the cylinder 60.1 via a suction pipe 76 originating in the agent vessel 30. The cylinder 60.1 is accessed via the suction pipe 76 and a discharge pipe 78. The pipes 76 and 78 are fitted with suitable non-return valves to ensure a single direction flow of agent there along (not shown). During the suction stroke the pipe 78 is consequently closed off by its non-return valve.

Once the cylinder 60.1 is charged with agent a fluid flow selection valve 80 (as shown in figure 1 ) is switched over having the effect of changing the flow of pressurised air to enter the cylinders 60 via the connection 74 and through the branched tubing 68.2 thus via the blocks 66.2, 66.3 and 66.4 into the cylinders 60 from the opposite side as from that from which suction was achieved, as shown in figure 8(d). The pistons 62 are consequently urged to become displaced along the delivery stroke of the pump 28 in the direction of arrow 82, as progressively shown in figures 8(e) and 8(f). This has the effect of urging agent from the pump 28 via the pipe 78 to the nozzle 16 or the ejecting layout 22 depending on how the delivery of pressured agent is selected via the switching valve 48. Air situated on the opposite sides of the pistons 62 (that was sucked in during the suction stroke) is exhausted via the branched tubing 68.1 and the connection 70 that is also appropriately connected downstream to permit such exhaustion. As the piston movement in both the agent suction and ejection directions is rapid once the pump 28 is exposed to pressurised air, the agent is supplied at a high pressure. This has the result that the cleaning agent is supplied at a strong injection force into the chamber 14 in turn promoting a strong and rapid flushing or washing effect, whichever selected, on the spray gun 18.

While not shown in detail the internal piping layout of the cleaner 10 also provides for the direct application of pressurised air to the layout 22 as a final cleaning step. This is achieved via a pneumatic fluid flow selection valve 86 that switches the internal piping between supplying the compressed air to either the pump 28 or directly to the layout 22, whichever selected.

The cleaner 10 is also fitted with gas and fume absorbing media in the form of filters 88 situated along its internal piping to remove fumes and gases formed within the hoppers 12 and 38 during operative use of the cleaner 10.

The various fluid flow selection valves 48, 80 and 86 are consequently used during various steps of the cleaning process; the valve 80 for changing the pump 28 from suction to agent ejection, the valve 48 for switching the cleaning process between the nozzle 16 and the layout 22 and the valve 86 for selecting either agent or pressurised air during the cleaning process.

Use of the cleaner 10 normally involves the initial manual cleaning of a spray gun 18, as fully assembled, in the pre-wash box 44 using spent agent from the collection vessel 40. Agent drained to the collection vessel 40 normally incorporates heavy sediment and the box 44 is naturally pre-cleaned before use. The next step involves the location of the spray gun 18 still in its fully assembled condition via its inlet port as fitting the nozzle 16 in upside down relationship within the chamber 14, as shown more clearly in figure 2 for flushing of the interior of the spray gun 18 by way of the heavy duty cleaning cycle. The lids 36, 46 of both boxes 34, 44 are then sealably closed.

To charge the pump 28 with agent the valve 80 is appropriately set while the valve 48 is set for the supply of agent to the nozzle 16 and the valve 86 for air supply to the pump 28. Once the pump 28 is charged the valve 80 is switched over having the effect of injecting agent under high pressure into the spray gun 18 for its heavy duty internal cleaning. This step can naturally be repeated by appropriate repetitively switching over the valve 80.

Once the interior of the gun 18 has been desirably flushed and agent has drained to an adequate extent from the spray gun 18 the box 34 is opened, the air inlet to the spray gun 18 fitted with the adapter 32 and the gun 18 in inverted though still fully assembled condition re-positioned in its upright condition in the chamber 14 and held against toppling by the adapter 32 as firmly engaging with the washer nozzle 26. The chamber 14 is again sealed off and the valve 48 is appropriately switched over to direct the flow of agent to the cleaning layout 22 used for normal cycle external and internal washing of the gun 18 via the operation of the pump 28. The cleaning step can naturally also be repeated. The final step involves the appropriate selection of the valve 86 to directly blow air through and onto the spray gun 18.

During the full extent of the cleaning process the zone in which cleaning takes place is fully closed off from the environment while fumes and gases formed during the cleaning process are absorbed by the filters 88. As the cleaning of spray guns 18 is done by a highly volatile agent such as thinners its containment during the cleaning process limits environmental pollution and equally important, the exposure of the person performing the process thereto except to an insignificant extent during the pre-wash.

Owing further to the agent being made available at a high pressure, only a small amount is necessary to achieve proper flushing and washing, as compared to the present manual cleaning technique. Typically in the order of 150 ml of thinners is required to perform a full washing cycle as compared to an amount of 2 litres or more when cleaning conventionally manually done.

Another very important advantage of the invention as specifically described is that pressurised air is used to power the cleaner 10. This effectively excludes the possibility of any fire hazard that would otherwise have existed should electricity have been used as source of power.

A practical advantage is that a spray gun desired to be flushed and cleaned by means of the method and equipment of the invention need not be disassembled. The otherwise time consuming effort is thus replaced by a rapid flushing and cleaning approach that naturally extensively reduces the downtime of spray gun equipment.

Finally the spent agent from the sprayed and flushed cleaning process is collected for re-use in the pre-cleaning process and only then re-cycled to be purifying again.

Claims

(6) CLAIMS

(1 ) A method of cleaning at least the interior of apparatus from time to time requiring such by way of an environmentally harmful cleaning agent under conditions of reduced if not minimised environmental inclusive of human exposure thereto at least during the performance of the cleaning procedure comprising injecting a charge of fluid cleaning agent by way of a high pressure injection action into the apparatus arranged to be so injected, and as held against environmental release of agent, to the extent of performing a proper cleaning action while dealing with substance thus removed by the cleaning process and as carried by the cleaning agent, where so involved, in a way that reduces environmental exposure thereto.

(2) A method as claimed in claim 1 that comprises dealing with substance thus removed by the cleaning process by collecting it for subsequent dealing therewith.

(3) A method as claimed in claim 1 or claim 2 that comprises injecting a fluid cleaning agent in the form of a liquid cleaning agent into the apparatus thus flushing substance desired to be removed there from.

(4) A method as claimed in claim 3 that involves suitably maintaining the apparatus during at least the cleaning process thereby to promote the gravitational draining of at least part of the spent cleaning agent, as carrying substance thus removed by the cleaning action, from the apparatus.

(5) A method as claimed in any one of the preceding claims that comprises also cleaning the outside of the apparatus though not necessarily simultaneously during the cleaning of its interior.

(6) A method as claimed in any one of the preceding claims that involves applying pressurised air in the cleaning process once the apparatus has been exposed to agent for aiding in its final cleaning and drying.

(7) Cleaning equipment (10) for at least cleaning the interior of at least one cleaning equipment matching apparatus (18) without requiring its disassembling in the case of being so disassemblable and that from time to time requires exposure to an action of interior cleaning, by way of an environmentally harmful and electrical spark sensitive cleaning agent under conditions of reduced if not minimised environmental inclusive of human exposure to such agent during at least the performance of the cleaning procedure comprising cleaning chamber defining means (12) defining a cleaning chamber (14) extending to housably hold such apparatus (18) against displacement at least when ready for being cleaned and during cleaning and in a way that enables its positioning for cleaning and removal in an uncomplicated way, and injection means (16) suitably mounted to the cleaning chamber defining means (12) and configured to inject fluid cleaning agent, as supplied from a pressurised fluid source (28), into such apparatus (18) once cleanably held in the chamber (14) to the extent of performing a proper cleaning action on the interior of such apparatus (18) with the equipment (10) being arranged to deal with substance removed by the cleaning process at least in the case where carried along by such cleaning agent in a way that reduces environmental exposure thereto; characterised in that the cleaning chamber defining means (12) is formed to at least limit if not effectively prevent the environmental release of cleaning agent there from once the equipment (10) is operatively used while the latter is driven by way of pressurised fluid thereby limiting the possibility ignition of cleaning agent during operation of the equipment (10).

(8) Cleaning equipment as claimed in claim 7 in which the injection means is in the form of a flushing facility (16) for flushingly injecting a liquid agent into the equipment (10).

(9) Cleaning equipment as claimed in claim 8 in which the flushing facility is in the form of at least one flushing nozzle (16) formed to snugly fit into the mouth of a passage extending into the interior of apparatus (18) as appropriately formed.

(10) Cleaning equipment as claimed in 9 in which the flushing nozzle (16) is mounted to face upward into the cleaning chamber (14) while serving to at least partly hold apparatus (18) intended to be cleaned owing being matchingly formed to project against agent escape into a flushing inlet of such apparatus (18) once the equipment (10) is ready for use, agent that has been injected into such apparatus (18) during a cleaning action and flushed substance thus becoming gravitationally drained from such equipment (10).

(11 ) Cleaning equipment as claimed in any one of claims 8 to 10 that is constituted for also enabling at least the cleaning of the outside of apparatus (18) housed for cleaning, even if requiring its re-location as compared to its positioning during the step of internal flushing, by way of a cleaning liquid washing layout (22) comprising at least a set of strategically situated washing jets (24) suppliable with agent from the pressurised fluid source (28) while not necessarily being coupled for performing its apparatus outside cleaning function simultaneously with the flushing facility (16) at least in the latter case of which the equipment is fitted with appropriate piping and a switchover valve for diverting pressurised agent to either the flushing facility (16) or the washing layout (22) for performing a flushing or an external washing operation, whichever selected.

(12) Cleaning equipment as claimed in claim 11 in which the cleaning liquid ejecting layout (22) also includes a secondary apparatus interior washer (26) that is suitably mounted within the cleaning chamber (14) to firmly hold appropriate apparatus (18) in a flushing facility noninterference manner while being interspaced along the cleaning liquid ejecting layout supply piping for injecting cleaning agent into the interior of such apparatus (18) simultaneously with washing its outside by way of the cleaning liquid washing layout (22) thereby to perform a reduced pressure secondary apparatus interior washing action (as compared to the high pressure injection action of the flushing means) during external apparatus cleaning.

(13) Cleaning equipment as claimed in claim 11 or claim 12 that is fitted with appropriate piping and a switchover valve (48) for diverting pressurised agent to either the flushing facility (16) or the washing layout (22) in the appropriate case inclusive of the secondary apparatus interior washer (26), for performing a flushing or an external and in the appropriate case inclusive of an internal washing operation, whichever selected.

(14) Cleaning equipment as claimed in any one of claims 8 to 14 in which the pressurised fluid source is in the form of a pneumatically driven pressuriser (28) that is pneumatically powerable from an external pneumatic source for pressurising liquid cleaning agent supplied from a batch source.

(15) Cleaning equipment as claimed in claim 14 in which the pressuriser is in the form of a , pneumatically operable to and from displaceable multi-inline piston layout pump (28) of which displacement of the piston layout (56) in the one direction results in the filling of the pump (28) by agent from an agent batch source (30) and displacement in the opposite direction causes the supply of pressurised agent for appropriate application.

(16) Cleaning equipment as claimed in any one of claims 8 to 15 that includes a fluid flow switching valve (86) for substituting the supply of cleaning agent to the cleaning liquid washing means (22) with air from a pneumatic supply (54) thereby to blow air over and in the appropriate case through apparatus (18) mounted in the cleaning chamber (14) in contributing to its cleaning process.

(17) Cleaning equipment as claimed in any one of claims 8 to 16 that is arranged to deal with agent removed by the cleaning process by way of a collecting layout (38) as incorporated into the equipment (10) in which spent agent and removed substance is collectable. (18) Cleaning equipment as claimed in any one of claims 8 to 17 that incorporates a pre- wash facility (44) employable for the manual pre-washing of apparatus

(18) requiring even of by spent agent as appropriately collected.

(19) Cleaning equipment as claimed in any one of claims 7 to 18 that is fitted with gas and fume absorbing media (88) situated for absorbing gases and fumes generated during the cleaning process in a way that reduces environmental exposure thereto.

(20) Cleaning equipment as claimed in any one of claims 7 to 19 that is constituted to be used for the cleaning of paint application spray guns used for, amongst others, vehicular spray painting, without requiring their disassembling, by means of an agent in the form of a solvent.