WO2011114085A1

WO2011114085A1 - A parts washer

Info

Publication number: WO2011114085A1
Application number: PCT/GB2010/050452
Authority: WO
Inventors: Brady Collins; Peter John Gee; Chris Prince
Original assignee: PSI INNOVATION Ltd
Current assignee: PSI INNOVATION Ltd
Priority date: 2010-03-16
Filing date: 2010-03-16
Publication date: 2011-09-22
Anticipated expiration: 2012-09-16

Abstract

A parts washer (1) comprises a storage tank (5) for storing cleaning liquid, a part cleaning chamber (7) in which a part to be cleaned can be placed, and means to deliver cleaning liquid from the storage tank (5) into the cleaning chamber (7), The parts washer (1) further comprising a vapour recovery apparatus (8) comprising a conduit connected to a vacuum device (21), means to pump driving fluid through the conduit and vacuum device (21) such that a vacuum is induced operative to draw cleaning liquid vapour into the vacuum device (21) such that the cleaning liquid vapour condenses into cleaning liquid, a return being provided to return the condensed cleaning liquid to the storage tank (5).

Description

A PARTS WASHER

The present invention relates to a parts washer.

It is know to provide a parts washer of the type comprising a storage tank of cleaning liquid, a part cleaning chamber in which the part to be cleaned is placed in use, and a pump or the like to deliver cleaning liquid from the storage tank to the cleaning chamber.

Such cleaning liquid vapourises in the storage tank or in the cleaning chamber and the cleaning liquid vapour is typically extracted from the parts washer using an extractor fan assembly or the like. This results in a significant quantity of the cleaning liquid being lost, and also emits potentially harmful/dangerous levels of the cleaning liquid vapour from the exhaust of the extractor fan assembly to the external atmosphere or into the building in which the parts washer is located.

According to a first aspect of the invention there is provided a parts washer comprising a storage tank for storing cleaning liquid , a part cleaning chamber in which a part to be cleaned can be placed, and means to deliver cleaning liquid from the storage tank into the cleaning chamber, the parts washer further comprising a cleaning liquid vapour recovery apparatus comprising a conduit connected to a vacuum device, means to pump driving fluid through the conduit and vacuum device such that a vacuum is induced operative to draw cleaning liquid vapour into the vacuum device such that the cleaning liquid vapour condenses into cleaning liquid, a return being provided to return the condensed cleaning liquid to the storage tank. The driving fluid may comprise cleaning liquid from the storage tank. The driving fluid may alternatively comprise a gas , such as compressed air, from a separate source .

Preferably cooling means are provided to cool the driving fluid prior to the driving fluid entering the vacuum device, the cooling facilitating the condensing of the cleaning liquid vapour into cleaning liquid.

The cooling means may comprise a heat exchanger through which the driving fluid is pumped.

The cooling means may comprise part of a cooling system fitted to the storage tank.

The cooling means may comprise a vortex cooler comprising an elongate, tubular swirl chamber having a radially orientated fluid inlet, an axially orientated cool fluid outlet, and an axially orientated hot fluid outlet provided by a peripheral annular gap between the wall of the swirl chamber and a conical nozzle at that end of the swirl chamber, the vortex cooler being operative to generate a cooled fluid stream and a hot fluid stream, and to deliver the cooled fluid stream.

The cooling means may comprise a double venturi assembly comprising a first venturi through which gas is pumped to create a vacuum that draws in the cleaning liquid, and a second venturi into which warm gas is pumped to create a vacuum that draws in the cleaning liquid-gas flow from the first venturi, the assembly being operative such that the cleaning liquid-gas flow mixes with the warm gas and expands from the second venturi such that the liquid-gas flow is cooled. The vacuum device may be mounted at the storage tank so as to draw cleaning liquid vapour from the storage tank in use.

The parts washer preferably comprises a free board area in which cleaned parts are held after having been cleaned, the, or another, vacuum device being mounted at the free board area so as to draw cleaning liquid vapour from the free board area in use.

The parts washer preferably comprises a vent stack operative to vent the parts washer in use, the, or another, vacuum device being mounted at the vent stack so as to draw cleaning liquid vapour from the vent stack in use.

The vacuum device may comprise a venturi pump comprising a restriction that serves to increase the flow velocity of the driving fluid and thus reduce the pressure to generate a vacuum at the restriction.

Preferably a plurality of venturi pumps are provided . The vacuum device may comprise an air bar comprising an inlet duct which receives driving fluid , the duct being formed with a longitudinally extending slit extending along at least part of the length of the duct, a longitudinally extending, curved wing extending along the length of the slit, driving fluid, in use, being pumped along the duct and passing through the slit so as to form a laminar flow across an upper curved face of the wing to create a low pressure area to draw the cleaning fluid vapour across the wing.

Other aspects of the present invention may include any combination of the features or limitations referred to herein . The present invention may be carried into practice in various ways, but embodiments will now be described by way of example only with reference to the accompanying drawings in which :

Figure 1 is a view from the side of a parts washer in accordance with the present invention, with part of the parts washer enlarged;

Figure 2 is a view from the side of another parts washer in accordance with the present invention,

Figure 3 is a view from the top of a parts washer in accordance with the present invention fitted with an alternative vacuum device, with part of the vacuum device enlarged and the top part of the washer removed for clarity ;

Figure 4 is a view from the side of the parts washer of Figure 3, with part of the vacuum device enlarged and the top part of the washer removed for clarity; and Figure 5 is a view from the side of a further parts washer in accordance with the present invention.

Referring initially to Figure 1 , a parts washer 1 comprises a housing 3 containing a cleaning liquid storage tank 5. The tank 5 is located below a cleaning chamber 7 provided with a drain in communication with the tank 5. A pump or the like (not shown) is provided to deliver cleaning fluid from the tank 5 into the cleaning chamber 7 to clean a part that has been placed in the cleaning chamber 7. A jig or the like (not shown) may be provided in the cleaning chamber 7 to support the part to be cleaned. The parts washer 1 is provided with a vapour recovery apparatus 8 to recover cleaning fluid vapour generated from cleaning fluid in the tank 5 and in the cleaning chamber 7.

The vapour recovery apparatus 8 comprises a pump 9 operative to pump driving fluid such as cleaning liquid from tank 5 to cooling means which in this example comprises a vortex cooler 11 and a heat exchanger 13.

The vortex cooler 11 comprising an elongate, tubular swirl chamber having a radially orientated gas inlet, an axially orientated cool gas outlet, and an axially orientated hot gas outlet provided by a peripheral annular gap between the outer wall of the swirl chamber and a conical nozzle at that end of the swirl chamber. The gas inlet is connected, to a suitable source of pressurised gas which may comprise a compressed air supply.

A cleaning fluid flow path is defined by suitable conduit through the heat exchanger 13 so that relatively warm cleaning fluid enters a heat exchanger inlet 15 and relatively cool fluid exits the heat exchanger 13 via a heat exchanger outlet 17.

The heat exchanger outlet 17 is connected via pipework 19 to a vacuum device 21 mounted above the cleaning chamber 7. In this example, the vacuum device 21 comprises a plurality of venturi pumps 22 spaced along the top of the cleaning chamber 7. Each venturi pump 22 comprises a conduit 20 through which the cooled cleaning fluid is pumped. The conduit 20 comprises a restriction 23 that serves to increase the flow velocity of the fluid and thus reduce the pressure to generate a vacuum at the restriction 23. This vacuum is open to the cleaning chamber 7. A cooling device comprising a cooling bar 24 is provided adjacent the vacuum device 21 . The cooling bar 24 may comprise a plurality of cooling coils containing refrigerant or the like, as required, and may comprise part of an integral cooling system of the parts washer 1. Pipework 25 connects the outlet end of the vacuum device 21 to a changeover valve or valves 27 that is/are connected to a second vacuum device 31 mounted in a free board area 33 of the washer 1. The free board area 33 is an area cleaned parts enter prior to exiting the washer 1.

The second vacuum device 31 comprises an outlet connected to return pipework to deliver cleaning fluid back to the storage tank 7.

A vent stack 35 is provided that vents the freeboard area 33 to atmosphere.

In use of the parts washer, cleaning liquid is pumped by pump 9 to the heat exchanger 13. One side of the heat exchanger 13 is subject to cooling via air cooled by the vortex cooler 1 1.

Compressed air supplied to the vortex cooler 11 flows tangentially into the swirl chamber of the vortex cooler 1 1 . The compressed air accelerates in the swirl chamber and separates into a hot and a cold air stream . The hot air stream moves radially outwardly within the swirl chamber and exits via the hot air outlet. The cold air stream is rebounded by the conical nozzle at the hot air outlet and flows back along the swirl chamber to exit into the heat exchanger 1 3. This cold air stream provides cooling to one side of the heat exchanger 13. Heat is exchanged in the heat exchanger 1 3 between the cold air stream from the vortex cooler 11 and the warmer cleaning liquid. This exchange serves to cool the cleaning liquid which is then pumped to the vacuum device 21. The flow of cooled fluid past the orifices 23 of the venturi pumps 22 of the vacuum device 21 draws cleaning fluid vapour from the cleaning chamber 7 into the vacuum device 21 . The fluid vapour is cooled by the cooler cleaning liquid circulating through the vacuum device 21 and this condenses the cleaning liquid vapour into the circulating cleaning liquid. The circulating cleaning liquid, with condensed vapour, flows, via changeover valve 27, into second vacuum device 31 where the same process occurs to draw in, and condense, any vapour contained in the free board area 33.

The circulating cleaning liquid, with vapour condensed from vacuum devices 21 , 31 is then returned to the cleaning liquid tank 5 for reuse.

The vent stack 35 serves to vent any gas overpressure within the parts washer 1.

In a modified embodiment of the above parts washer 1 , a further venturi pump 22 could be provided in the vent stack 35 to draw in, and condense any vapour from the vent stack 35.

The above described washer 1 serves to reuse all or a substantial part of the cleaning liquid vapour by returning the condensed cleaning liquid to storage tank 5 via a return such as a suitable conduit or aperture into the tank 5. This serves to reduce the cost of cleaning fluid wastage, and to minimise potentially harmful fluid vapour emissions . By additionally drawing vapour from the free board area 33, the user of the washer 1 will be subjected to less vapour when removing the cleaned part.

Referring to Figure 2, the parts washer 1 is shown with the second vacuum device 31 omitted. Referring additionally to Figures 3 and 4, the parts washer 1 is shown fitted with another vacuum device 41 as an alternative to the venturi pumps 23 of vacuum device 21.

The vacuum device 41 comprises an air bar 43 fitted across the storage tank 7 of the parts washer 1 . The air bar 43 comprises an inlet 45 which receive fluid or gas from a conduit comprising an inlet duct 47. The inlet duct 47 extends along the length of the air bar 43 and is formed with a longitudinally extending , laser cut, slit 49. A longitudinally extending, curved wing 51 extends along the length of the bar 43 adjacent the slit 49. In use, driving fluid, which may be for example, the cleaning fluid from tank 7, or compressed air from an external air supply, is pumped along duct 47. The driving fluid passes through the slit 49 and forms a laminar flow across the upper curved face 53 of wing 51 . This creates a low pressure area along the opposite side of the duct 47 to the wing 51. This area of low pressure pulls the cleaning fluid vapour across the top of the tank 7 and down onto the refrigerated tubing. The vapour then recondenses back into cleaning fluid liquid for return to the tank 7.

It is envisaged that that the driving fluid may be pre-cooled prior to being pumped along duct 47 using for example a vortex cooler 1 1 and heat exchanger 13 as described above, or by using the cooling bars 24. Referring additionally to Figure 5 , the parts washer 1 is modified to include a different cooling means.

In this example, the vortex cooler 1 1 is removed and replaced with a double venturi assembly 61 mounted at heat exchanger 13 inlet 15. Air from a suitable source of compressed air (not shown) is blown through air inlet 63 into a first venturi 65. This air flow generates a vacuum that draws cleaning fluid through conduit 67 from storage tank 5 into first venturi 65.

The cleaning fluid flow from first venturi 65 then enters a second venturi 69 where it is mixed with a warm air bypass flow from warm air conduit 71 . The cleaning fluid-air mixture is then expanded 73 as it exits second venturi 69 which creates considerable refrigeration of the fluid-air mixture. This uses the evaporation qualities of the cleaning liquid whose vapour is to be recovered . An example of such liquid would be Petrol Methylene Chloride.

Claims

1. A parts washer comprising a storage tank for storing cleaning liquid, a part cleaning chamber in which a part to be cleaned can be placed, and means to deliver cleaning liquid from the storage tank into the cleaning chamber, the parts washer further comprising a cleaning liquid vapour recovery apparatus comprising a conduit connected to a vacuum device, means to pump driving fluid through the conduit and vacuum device such that a vacuum is induced operative to draw cleaning liquid vapour into the vacuum device such that the cleaning liquid vapour condenses into cleaning liquid, a return being provided to return the condensed cleaning liquid to the storage tank.

2. The parts washer of claim 1 wherein the driving fluid comprises cleaning liquid from the storage tank.

3. The parts washer of claim 1 wherein the driving fluid comprises a gas, such as compressed air, from a separate source .

4. The parts washer of any one of claims 1 to 3 wherein cooling means are provided to cool the driving fluid prior to the driving fluid entering the vacuum device, the cooling facilitating the condensing of the cleaning liquid vapour into cleaning liquid.

5. The parts washer of claim 4 wherein the cooling means comprises a heat exchanger through which the driving fluid is pumped.

6. The parts washer of claim 4 or claim 5 wherein the cooling means comprises part of a cooling system fitted to the storage tank.

7. The parts washer of claim 4 or claim 5 wherein the cooling means comprises a vortex cooler comprising an elongate, tubular swirl chamber having a radially orientated fluid inlet, an axially orientated cool fluid outlet, and an axially orientated hot fluid outlet provided by a peripheral annular gap between the wall of the swirl chamber and a conical nozzle at that end of the swirl chamber, the vortex cooler being operative to generate a cooled fluid stream and a hot fluid stream, and to deliver the cooled fluid stream.

8. The parts washer of claim 4 or claim 5 wherein the cooling means may comprise a double venturi assembly comprising a first venturi through which gas is pumped to create a vacuum that draws in the cleaning liquid , and a second venturi into which warm gas is pumped to create a vacuum that draws in the cleaning liquid-gas flow from the first venturi, the assembly being operative such that the cleaning liquid-gas flow mixes with the warm gas and expands from the second venturi such that the liquid-gas flow is cooled.

9. The parts washer of any one of the preceding claims wherein the vacuum device is mounted at the storage tank so as to draw cleaning liquid vapour from the storage tank in use .

10. The parts washer of any one of the preceding claims wherein the parts washer comprises a free board area in which cleaned parts are held after having been cleaned, the, or another, vacuum device being mounted at the free board area so as to draw cleaning liquid vapour from the free board area in use.

11 . The parts washer of any one of the preceding claims wherein the parts washer comprises a vent stack operative to vent the parts washer in use, the, or another, vacuum device being mounted at the vent stack so as to draw cleaning liquid vapour from the vent stack in use.

12. The parts washer of any one of the preceding claims wherein the vacuum device comprises a venturi pump comprising a restriction that serves to increase the flow velocity of the driving fluid and thus reduce the pressure to generate a vacuum at the restriction.

13. The parts washer of claim 12 wherein a plurality of venturi pumps are provided.

14. The parts washer of any one of the preceding claims wherein the vacuum device comprises an air bar comprising an inlet duct which receives driving fluid, the duct being formed with a longitudinally extending slit extending along at least part of the length of the duct, a longitudinally extending, curved wing extending along the length of the slit, driving fluid, in use, being pumped along the duct and passing through the slit so as to form a laminar flow across an upper curved face of the wing to create a low pressure area operative to draw the cleaning fluid vapour across the wing.