GB2134002A - Vehicle-cleaning apparatus - Google Patents

Abstract

An apparatus for cleaning the external surfaces of vehicles such as trains and coaches, by chemical foam coverage, includes a positive displacement pump (1) for mixing a chemical cleaning product (3) with a diluent (2). The pump functions not only as a compressor but also as a mixer by receiving liquid at a rate representing only part of its capacity, and the foamable liquid may be further mixed as it is passed through a conduit (16) which is conventionally fitted with gauzes of appropriate mesh. The chemical product, in liquid form, and the liquid diluent may be gravity fed to the pump which is preferably of the lobe or sliding-vane type. The apparatus also comprises a series of movable spray jets (19) mounted on an arch corresponding to the shape of the vehicle to be cleaned when moving under the arch. <IMAGE>

Description

SPECIFICATION Vehicle-cleaning apparatus This invention relates to an apparatus for the application of chemical fluids for cleaning the external surfaces of vehicles such as trains, coaches, and load carrying vehicles of all types.

Known apparatus for this purpose may apply such chemical fluids to the vehicle surfaces in the form of retentive foams, this retention being provided to enhance the period of contact between the chemical and the surface soiling over which it is applied, thus to prolong the chemical action.

By way of non-limitive example such foams are frequently generated from complex fluids constituted from acids, alkalis, solvents, detergents, viscosity builders, foaming agents and the like. For simplicity, such complex fluids are hereafter referred to as "cleaning products".

Such cleaning products are frequently, but not necessarily, diluted with appropriate diluents and mixed in appropriate proportions such as are suited to the effective penetration of type and extent of the soiling present on the surface of the vehicle. It is common practice, though not necessarily appropriate in all cases, to provide water as the diluent.

It is also common practice to employ appropriate mixing equipment such as sitrrers, blenders and the like, and to employ proportioning pumps or other mechanical devices, the output of which can be adjusted to provide the required proportion of cleaning products with its appropriate diluent.

It is also conventional practice to generate the required strength of cleaning product from powdered or granulated constituents, by manually or mechanically loading them into tanks of appropriate diluent, to dissolve them in appropriate ratios, and thereafter deliver the resultant liquor through conventional pumping equipment to spray apparatus.

Such spray apparatus is normally provided by an appropriate number of jets, suitably located and spaced on an arch through which the vehicle is passed, or which, alternatively, can be passed over the vehicle. These same jets conventionally are statically located on the arch to deliver the foamed product in a fixed delivery pattern on to the vehicle surface, and at right angles to it, with the intention of covering it overall.

Since this fixed spray pattern does not effect coverage of the ends of the vehicle as it passes through, nor for any inset parts of the vehicle surface which lie at right angles to the line of passage of the vehicle, such areas inevitably do not receive adequate chemical coverage, and in consequence detract from the efficiency of the foamed chemical application process.

To generate the retentive foam referred to above it is usual to employ conventional compressed air apparatus in appropriate form, to aerate and propel the chemical product from the spray jets.

Thus, known apparatus for achieving chemical foam coverage of vehicles in the manner described comprises: (a) A mixing arrangement for integrating its diluent with the product.

(b) Proportioning equipment for providing (a) above with the dilution appropriate to the cleaning operation.

(c) Pumping equipment (which may or may not be integrated with (b) above), to deliver the diluted product to apparatus in which compressed air is introduced to generate the retentive foam.

(d) Compressed air apparatus, normally comprising a compressor and receiver, each of such performance as will permit of sustained foam generation and application. This, in the case of train cleaning, may require plant of considerable cost.

The objects of this invention are: (1) To simplify and thus to reduce the cost of installations such as are presently provided for the foamed method of chemical application.

(2) To provide a simplified gravity-controlled method of proportioning the chemical and diluents employed.

(3) To provide a simplified method of foam generation.

(4) To provide an improved foam chemical spray system such as will provide total foam coverage of vehicles passed through it (5) To provide a simple method of continuously dissolving powdered or granulated cleansing agents in their appropriate diluents, and delivering them in predetermined ratios into the foam producing apparatus hereafter described.

According to the present invention, methods of achieving the functions described at (1 )-(5) above are incorporated in simple apparatus which thus reduces manufacturing, installation, running and maintenance costs.

The invention provides for the use of a positive displacement pump of any suitable design and capacity such as will, when its internal rotating or sliding parts are wetted by and thus substantially sealed against pressure loss by the admission of part of its total capacity by way of controlled quantities of foamable liquid and diluent, permit the remaining capacity of the pump to function as a compressor, whilst thoroughly mixing the foamable liquid through a suitably constructed vessel conventionally fitted with gauzes of appropriate mesh.

The pump referred to above will be preferably, but not necessarily, of the "lobe" or sliding vance type and will be capable of being run at speed such as will generate a pressure of foam of the order of 1 bar.

In order that the invention may be fully understood, some of its embodiments will now be described by way of non-limitative example, and with reference to the accompanying drawings, in which Fig. 1. Shows diagrammatically the components of the foam producing and oscillating discharge apparatus; Fig. 2. Showsaiagrammatically, by way of nonlimitative example, components employed in a typical arrangement for distribution of foamed chemical in the desired spray pattern; Fig. 3. Shows diagrammatically an alternative device for providing a controlled aqueous concentration of powdered or granulated cleaning product.

According to the present invention, and with reference to Fig. 1, the requirement for pre < iilution of the cleaning product and mixing it with its diluent is achieved by discharging them in appropriate and controlled quantities directly into the intake of the positive displacement pump (1) referred to above.

To achieve this function, a suitable volume of undiluted product and its diluent are each maintained at a constant gravity head in small tanks (3) and (2) respectively, which are appropriately situated above the inlet to pump (1).

When, as is common practice, water is employed as diluent, and is supplied under pressure from a mains water supply, a head of water is maintained constant in tank (2) by means of a conventional ball-cock (4). For the undiluted product, a constant head (usually the same as that for its diluent) is maintained by providing tank (3) with a simple weir (5) which is continuously supplied with a volume of undiluted product in excess of that required for foam production by a small independently-driven pump (6), drawing product via cock (7) from a bulk holding tank (8), into which the excess product drains back from the weir (5).

The continuous supply of product into the tank (3) passes through a spring-loaded relief valve (9), which on its down-stream side maintains the product at a pressure adequate to feed, via cock (10) and appropriate lengths of flexible hose, hand-held brushes with which the operators can deal with any areas of abnormally heavy contamination on the vehicle surface, or areas not covered by the overall spray pattern.

From their respective tanks (2) and (3), diluent and undiluted product discharge by gravity, through solenoid-activated valve (11) and (12), which may be electrically phased to function simultaneously with conventional ON/OFF "Start" and "Run" switching provided for controlling the positive displacement pump (1) referred to above.

From the solenoid-actuated valves, the liquids flow by gravity through appropriate lengths of pipe through predetermined and appropriately sized orifi (13) and (14) such as will provide the desired dilution, and thence into the inlet side of the positive displacement (1) via a funnel-shaped vessel (15) which is open to atmosphere. This vessel is interposed between the discharge orifi (13) and (14) and the inlet to pump (1) to ensure that the volume of discharge is not affected by the reduced air pressure which occurs in the vicinity of this inlet, and that it is thus at all times governed only by the heads of liquid maintained in tanks (2) and (3).

The output of foamed chemical from pump (1 ) may be further chemically integrated by passing it through a series of gauzes in a pressure sealed container (16) and thence, via a suitably sized and shaped pipe (17), to a foam distribution unit shown at Fig. 2.

This foam distribution unit comprises a hollow chamber (27), which is fitted internally with a cone (28), or such other appropriate shape as will deflect the flow of foamed chemical into a pattern of hollow tubes indicated at (29), suitably spaced around the internal periphery of the chamber (27).

Each of these hollow tubes may be fitted with an appropriate length of flexible hose (not drawn), the extremities of which are attached to and deliver foam into suitably shaped blocks (18) bored and threaded to receive spray jets (19), and provided with means of clamping at appropriate locations on rods (21,22,23,24 and 25) in Fig. 1.

An alternative foam distribution method may be employed by which the rods (21, 22, 23, 24 and 25) are substituted by hollow tubes of appropriate bore, fitted at convenient locations in their lengths with flexible pipes which deliver foam from the distribution unit. These same tubes are provided with a fixed pattern of discharge orifi into which jets may be fitted, and they perform the same oscillating functions as described below.

To achieve object 4 of this invention, the rods (21-25) in Fig. 1 on which the jets are located so as to provide the desired spray pattern, are made to oscillate within an appropriate arc of movement generally, but not necessarily, of the order of 300 either side of a central location. The spray jets secured to the rods (21-25) will thus deliver the overall foam spray pattern in such manner as will ensure that all parts of the vehicle will receive a coating of foam, either when it is advancing towards or receding from the said spray pattern.

The volume of foam supplied to each of the spray jets may be controlled by reducing the internal capacity of the flexible tube via which it is supplied by a simple clamping device which squeezes the tube and thus diminishes the delivery of foam. Alternatively, the volume of foam delivered may be adjusted to operating requirements by fitting alternative sizes of jet.

Reference to Fig. 1 will show that the rods (21-25) are disposed in an arrangement appropriate to the contour of the vehicle to be cleaned, carried in bearings (20), and joined to each other by conventional double universal joints (not drawn) fitted at points (21).

The oscillation referred to above is achieved by providing one of these rods, normally the central horizontal rod (23) with a lever, connected to and actuated by a suitably located offset pin on a faceplate driven by a small electric geared motor. This same motor may conveniently be arranged to function in parallel with the electric motor provided to drive pump (1). The motor provided for the oscillating function will preferably be of the variable speed type, or a fixed speed motor fitted with variable speed gearing, such as will permit the rate of oscillation to be controlled to meet varied operating conditions. The extent of offset of the pin referred to above will preferably be adjustable, thus to permit variation of the arc of movement provided for the oscillating function.

For the support of the spray apparatus described above, from suitable sections of conventional structural materials, an arch structure (26) is provided with straddles the path along which the vehicle is passed through the spray pattern. This same arch may be so constructed as to move over a vehicle which remains static beneath it.

The arch may be fitted with panels and flexible curtains which will contain overspray, and will protect the spray pattern from adverse wind effects. Preferably, but not necessarily, this arch arrangement is erected from corrosion-proof materials.

The oscillating spray method described above may be employed to beneficial effect for the water-rinse which normally is sequenced to follow the application of the foamed chemical product.

With a fixed spray system, at the slow rate of passage of the vehicle through a water spray pattern, a layer of water builds up between the surface to be rinsed and the continued impingement of the water emanating from the sprays. This water barrier inhibits the effective impact performance of the continued supply of water discharging from the spray jet.

The oscillating spray effectively provides opportunity for this water layer or barrier to drain away from the surface before it is further impinged upon, thus increasing the efficiency of the rinse procedure.

To further simplify the overall cleaning function, and thus reduce installation costs, by a suitable simple arrangement of supply cocks and provision of an appropriate water supply, the foam producing pump (1) in Fig. 1, and the foam distribution system already described, may be alternatively employed to provide the water-rinse function which is normally sequenced to follow this foamed application of chemical product.

For circumstances in which the cleaning product is supplied in water-soluble powdered or granulated form, a controlled concentration of such product is provided by the apparatus indicated in Fig. 3, The function of this apparatus is based on the fact that in a constant volume of water, maintained at a constant temperature, a directly related and constant proportion of soluble solids can be taken into and maintained in solution.

In Fig. 3, an open-topped removable vessel (32) perforated overall on its sides, but with an unperforated base, is suitably suspended in the upper part of the tank (31). Within the vessel (32), an inner open-topped vessel (33), manufactured overall from materials of suitable mesh for retaining the powdered or granulated product, is located within the vessel (32) in such manner as to leave a suitable gap between these two vessels.

A constant level and hence a constant volume of liquid is maintained in tank (31) by a float actuated ballcockfitted in a small header tank (34), which is located in close proximity to tank (31), and interconnected with it as indicated in Fig. 3.

The header tank (34) is supplied with water from any convenient source, its level being set, in particular, when the supply is provided by the Water Authority, so as to maintain the statutory air gap between the incoming supply point and the level set in the header tank, thus to prevent the possibility of chemical contamination.

The contents of tank (31) thus held at constant volume, may be heated to and held at a preset temperature, appropriate to the desired concentration of powdered or granulated product by a thermostatically controlled heating element (36) suitably located in tank (31).

If so desired, the water supply into header tank (34) may be preheated from any alternative convenient source, such as gas or oil firing, to a temperature approaching but suitably below that set for the function of the apparatus, the requirement for the heating element (46) being then only to boost the temperature and thereafter maintain it at the predetermined level.

Thus, the requirements for close control of volume and temperature are achieved; the temperature of the liquid in tank (3) may be controlled to ensure constant viscosity, and the water temperature in tank (2) may also be controlled (Figure 1).

The unperforated base of vessel (32) is provided with a pipe (35) over the exit orifice of which a plate (36) is fitted so that liquid delivered from the pipe is deflected overall over the base of the inner vessel (33).

Powdered or granulated product is loaded into this inner vessel in such quantity as, without replenishment, will provide a supply of the said product in its appropriate strength of solution, without reloading, for an established cleaning programme.

An electrically-driven pump (37), preferably of the 'lobe' or similarly robust type is provided, the inlet of which is fed with liquid by a pipe (38) fitted into the side of tank (31). This same pipe is perforated overall in that part of its length which protrudes into the tank.

The discharge side of the pump (37) is fitted with a tee(39) which connects with the pipe (35) which passes through and is sealed against leakage from the base of tank (31), and which delivers to the underside of the plate (34), as already described. Liquid under pressure thus flows through the product loaded into the inner vessel (33), and enhances the dissolving action.

A second pipe (40) is fitted to the tee (39) through which, via a control cock (41), liquid discharges into the tank (35) to agitate its contents, thus to promote an overall even temperature and hence an overall concentration of product.

From a convenient point (42) on the side of the tank (31) a delivery pipe (43) fitted with a solenoid valve (44) delivers the aqueous concentration of powdered or granulated product under the constant head maintained in tank (31) to an appropriately sized orifice (45). From this orifice the aqueous concentration is discharged in controlled volume directly into the inlet of pump (1) of Fig. 1. At that point this discharge is met by the simultaneous discharge of water from the orifice (12) of Fig. 1, and is immediately thus diluted so that there will be no "throw-out" of solid due to temperature reduction. The simultaneous discharge referred to above will be effected by electrical inter-connection of solenoid valve (44) with solenoid valve (11) of Fig. 1, and further inter-connecting these two valves with the Start/Run control provided for the pump (1) of Fig. 1.

The water-soluble powdered or granulated products for which this apparatus is provided may, in some cases, be compounded without a foaming agent. In such cases, an appropriate foamable agent may be separately introduced directly into the inlet of pump (1) of Fig. 1, under the small header tank solenoid valve and controlled orifice configuration already described. If the foaming agent is highly viscous, it may be preferably to pre-dilute it to a controlled extent to promote its ready flow. Alternatively, such viscous foaming agents may be delivered into the inlet of pump (1) of Fig. 1 in controlled quantity directly from a small electrically driven positive displacement (metering) pump.

The operating temperature of the apparatus, as maintained by thermostatically controlled heating unit (46) will normally be set to the minimum appropriate to the production of an adequate, predetermined concentration of powdered or granulated product in water. This operating temperature will normally be suitably related to, and a few degrees higher than, the maximum temperature of the water supply anticipated in the area in which the apparatus is to be operated.

The thermostatically-controlled heat unit (46) may be interconnected with a suitable warning device so as to indicate when the temperature of the liquor in the tank (31) is below that predetermined for dissolving the required concentration of powdered or granulated product.

Preferably, the tanks (2), (3), (31) and (34), and their covers will be suitably lagged to obviate heat losses, as will other components of the system for which this is a convenient method of insulation.

Pipework, valves and other components of the system may be fitted with electrically actuated trace heating, the overall objective being to prevent temperature loss at any point such as would inhibit the temperature/volume/ concentration control under which the system functions.

Returning to Fig. 1, an outlet pipe (50) may be provided near the entry to pump (1) so that residual liquid, possibly formed from collapsed foam after a cleaning operation, can be drained down into a collector (51). Thus, the subsequent cleaning operation will start with foam rather than with liquid which could occur if a substantial quantity of residual liquid where to collect at and be drawn into the pump. After restart, the pump suction may draw the liquid back from the collector (51) and so minimise waste.

Modifications may be made without departing from scope of the invention. For example, pumps other than positive-displacement lobe or slidingvane type may be employed as at least the above pump (1). Also, the foam distribution application structures may be employed with alternative sources of cleaning fluid, and the described systems for producing the aqueous concentrations of powdered or granulated cleaning product may be applied by alternative means. In an alternative embodiment, proportional feed pumps may replace the gravity feed arrangement shown in Fig.

1 and, in a further alternative, a suitably diluted chemical product in liquid form may be fed to the pump (1). The apparatus may be in an alternative version be movable in relation to a stationary train.

The following advantageous features derive from the present invention: 1. A method of producing chemical foam by introducing controlled volumes of foamable liquid into a positive displacement pump of appropriate overall capacity. For example, a rotary pump operating at 700/800 r.p.m. may be fed with foamable liquid which will occupy of the order of 10% of its total capacity; such a pump would be considerably less expensive to install and also to maintain, than would be a conventional combination of compressor and reservoir.

2. A simplified method of producing these controlled quantities of pre-diluted foamable liquid from a concentrate liquid and its appropriate diluent.

3. A method of mixing the concentrate liquid and its diluent in the process of creating a resultant chemical foam.

4. A controllable method of distributing the chemical foam to a series of individual spray jets.

5. A method of delivering the chemical foam onto the surface to be cleaned in such manner as will ensure coverage of recessed areas.

6. A method of dissolving and delivering powdered or granulated products in controlled dilutions into the foam process described in the text relating to 2 above.

7. A method of employing a foam generating and distribution system of the additional function of water rinsing.

8. A method, inter-related with 5 above, for improving the effectiveness of the water rinse function.

Claims (14)

1. An apparatus for cleaning the external surfaces of vehicles such as trains and coaches by chemical foam coverage, comprising means for mixing a chemical cleaning product with a liquid diluent and forming a foam, said means comprising a positive displacement pump which, when its internal rotating or sliding parts are wetted by and thus substantially sealed against pressure loss by the controlled admission to part of its total capacity of the foamable liquid, permit the remaining capacity of the pump to function as a compressor and mix the foamable liquid.

2. An apparatus as claimed in Claim 1, and further comprising a chamber fitted with gauges of appropriate mesh to receive from said pump and further mix the foamed liquid.

3. An apparatus as claimed in Claim 1, wherein said pump is of the lobe or sliding-vane.

4. An apparatus as claimed in any preceding Claim, and further comprising a series of spray jets mounted on an arch corresponding to the shape of the vehicle to be cleaned when under the arch and moving relative to said arch.

5. An apparatus as claimed in Claim 4, wherein said jet nozzles are arranged to oscillate on axes transverse to the relative direction of movement of the vehicle.

6. An apparatus as claimed in Claim 4 or Claim 5, and further comprising foam distribution means to receive the output from said pump and having an internal cone to deflect the flow of foamed chemical into a pattern of tubes which deliver to said nozzles.

7. An apparatus as claimed in any preceding Claim, wherein controlled quantities of the chemical cleaning product in liquid form and of said liquid diluent are gravity fed from respective controlled reservoirs to inlet means to said pump, said inlet means being open to atmosphere.

8. An apparatus as claimed in any of Claims 1 to 6, wherein controlled quantities of the chemical cleaning product in liquid form and of said liquid diluent are fed to said pump by coordinated proportional-feed pumps.

9. An apparatus as claimed in any preceding Claim, and further comprising receiving means for a cleaning product in powdered or granulated form, said receiving means comprising an outer vessel to be at least partly submerged in a tank of diluent liquid and having an open top and sides which are perforated in their upper portions, and an open-topped inner vessel having a perforated base and perforated sides mounted in said outer vessel, so that powder or granules deposited in said inner vessel will dissolve and disperse firstly through the base and sides of the inner vessel and secondly through the perforated sides of the outer vessel to promote even distribution through the diluent liquid in said tank.

10. An apparatus as claimed in Claim 9, wherein means are provided for circulating the liquid in said tank and include a pipe extending through the imperforate base of said outer vessel to feed liquid upwardly to be deflected by a baffle plate below the perforated base of the inner vessel.

11. An apparatus as claimed in any preceding Claim, wherein a drain outlet for defoamed liquid is provided at the inlet to said pump.

12. An apparatus as claimed in Claim 11, wherein a reservoir is provided to collect defoamed liquid which may be recovered by entrainment through a conduit from said drain outlet, for use during a subsequent cleaning operation.

13. Apparatus for cleaning the external surfaces of vehicles such as trains and coaches, substantially as hereinbefore described with reference to the accompanying drawings.

14. The features as herein disclosed, or their equivalents, in any novel selection.