GB2447084A

GB2447084A - Power-washing equipment and method

Info

Publication number: GB2447084A
Application number: GB0704050A
Authority: GB
Inventors: John Hogan; Simon Antwis
Original assignee: Washtec UK Ltd
Current assignee: Washtec UK Ltd
Priority date: 2007-03-02
Filing date: 2007-03-02
Publication date: 2008-09-03
Anticipated expiration: 2027-03-02
Also published as: GB2447084B; GB0704050D0

Abstract

Power-washing equipment, particularly for cleaning the exterior of a vehicle comprises an electric motor 30 driving a pressure pump 31 and a flexible hose 12 connecting the pump to a washing lance 19. An electronic control arrangement 32, 33, 34 for the electric motor 30 is arranged to control the electrical power supplied to the motor such that when the pressure at the lance 19 is to be increased or decreased significantly, the pressure reduction take place over a user-appreciable period of time. In this way the user has sufficient time to respond to the change in pressure and provide the required reaction force for the lance 19, so obviating unexpected and unintentional movement of the lance. The control arrangement 32, 33 and 34 may also be arranged so that any increase in pressure also takes place over a pre-set period of time. A method of controlling the power-washing equipment is also disclosed.

Description

POWER-WASHING EQUIPMENT AND METHOD

This invention relates to power-washing equipment and also to a method of operating such equipment. Though not exclusively, this invention particularly concerns power-washing equipment for use in the manual washing of vehicles, such as may be installed in a garage forecourt or other area, for self-service use by a driver of or passenger in the vehicle.

Self-service car-wash equipment is widely installed on garage forecourts and usually comprise a jet washer, a vacuum cleaner and a tyre inflator. The normal self-service jet washer made available for use by an unskilled user typically comprises a foam brush which provides a pre-wash foam at a low pressure, and a pressure lance which is used mainly for rinsing purposes at a high pressure but also sometimes for the application at a low pressure of one or more washing components such as a wheel-cleaning chemical, a shampoo and a de-watering wax chemical.

The jet-washer equipment employs a controller having at least one in-built program but possibly several user-selectable programs whereby the equipment will follow a pre-determined sequence starting with the application of pre-wash foam using the foam brush and finishing with a final rinse from the pressure lance. The program determines which chemicals are discharged when, and sets the pressure to a low value for that, and to a high pressure for the rinsing, If there are userselectable programs, these may allow the customer to select which chemicals are to be applied and over what period of time, but these components are still applied at the same low pressure. The only difference from equipment having a single fixed program is that the customer determines the duration of application of the different components; with a single fixed program that has been pre-determined and the controller ensures that the required sequence is followed.

In order to achieve the required low and high pressures, the Jet-washer equipment usually employs an electrical motor-driven ceramic piston pump supplying water under pressure to a manifold, to which are attached several electro-magnetlc solenoid valves together with a mechanical by-pass valve. A by-pass solenoid valve (when open) allows flow from the manifold back to the pump Inlet, so the pressure In the manifold drops to a relatively low value such as 4,000 kPa (about 600 psi). The activation of the various solenoid valves allows the IntroductIon of the required chemicals Into the manifold while malntalnlng a relatively low manIfold pressure, but when rinsing is beIng performed the solenoid by-pass valve is closed so that the jet-washer allows thedeflveryofwaterfromthelanceatahighprre.

Duringuseoftheequipment,theuserwippuuonaffpj0 the lance, to open a valve to allow the flow of water under pressure out of the lance. The user has to hold the lance sufficIently firmly to provide a reaction to the force of the water issuing at high pressure from the lance nozzle. Release of the lance trigger stops the flow of water out of the lance, causing immedlate openIng of the punp by-pass valve so as to relieve the pressure on the pIston pump. The sudden cessation of the high pressure water Jet from the lance reduces the reaction force which is resisted by the user, and there Is likely to be a momentary deflection of the lance as the user endeavours to compensate for the variatIon In pressure at the lance none, If the user immedlately pit the trigger once more, there is the possibility of setting up an oscillating operation as the mechanical by-pass valve closes and the pressure out of the lance will be once more at the full operating pressure and yet the user may not immediately be able to provide a sufficient reaction force for that.

A further problem arises at the end of each phase of the operating program. The by-pass solenoid valve will be operated so that the pressure instantaneously changes from the low value to the high value or from the high value to the low value, or at the end of the program, to zero. Not infrequently, if the user has the nozzle very close to the body of the vehicle, when there is a sudden reduction in pressure at the lance, the reaction which was being provided by the user may result in the nozzle striking the vehicle body, which can lead to minor damage to the vehicle. This can also happen in the event that an inadvertent oscillating operation at high pressure occurs, as mentioned above, until the user once more gains full control of the lance.

In view of the above problems associated with known jet-washer equipment, it is necessary for the manufacturers to limit the maximum pressure of water supplied to the lance to less than a desired upper value for optimum washing and rinsing. This minimises the likelihood of accidental damage to a vehicle when the water under pressure to the lance is reduced or cut off, particularly at the end of a phase of the program or possibly should the user inadvertently instigate an oscillating action. Further, some chemical components could usefully be applied at a pressure intermediate the low and high values, but current commercial jet-washer equipment has no facility whereby this can be achieved.

It is a principal aim of the present invention to provide power-washing equipment which addresses the issues discussed above and thus allows the use of a higher pressure than is currently normally employed particularly in the case of car jet-wash equipment.

According to one aspect of this invention, there is provided power-washing equipment comprising art electrical motor drivingly coupled to a pump, a washing lance, a flexible hose connecting the pump to the lance and an electronic controller for the electric motor, the controller being arranged to control the electrical power supplied to the motor so that when the pressure at the lance is to be reduced from a relatively high value, the reduction in pressure takes place over a user-appreciable pre-set period.

According to a second and closely related aspect of this invention, there is provided a method of controlling power-washing equipment having an electrical motor drivingly coupled to a pump, a washing lance and a flexible hose connecting the pump to the lance, in which method an electronic controller for the electric motor reduces the electrical power supplied to the motor over a user-appreciable pre-set period when the pressure at the lance is to be reduced from a relatively high value.

It will be appreciated that with the power-washing equipment and method of this invention, the pressure at the lance is reduced from a relatively high value (and typically the maximum pressure which the equipment is able to deliver) to a lower value over a significant pre-set period. This may be when the pressure is to be reduced at the end of a particular phase of the program sequence or at the end of the operating program. In this way, the user is not confronted with a sudden and unexpected drop in pressure, consequent upon a phase of the program terminating. By reducing the pressure over a significant, user- appreciable period, the user may adjust to the change in pressure and so the likelihood of the nozzle at the forward end of the lance striking a vehicle body is greatly reduced.

The method may be enhanced by increasing over a pre-set period the electrical power supplied to the motor when the pressure at the lance is to be increased from a relatively low value to a higher value. Again, this allows the user to adjust to the increasing pressure and so maintain full control of the lance.

The method may yet further be enhanced in the event that the equipment is providing the maximum pressure and the user closes a trigger-operated valve associated with the lance, to terminate the supply of water under pressure from the lance, and then the user re-opens the valve. As mentioned above, with conventional jet-washer equipment, this can set up an oscillating action but this can be eliminated by the controller rapidly reducing the power supplied to the motor when the user closes the trigger-operated valve, so that the pump delivers a lower pressure; then on the user re-opening the valve, the controller may increase the power to the motor over a significant user-appreciable period back to the maximum.

Most preferably, the controller is arranged to allow operation of the motor at a minimum of three distinct speeds but possibly several distinct speeds. In the case of the former, there may be a low pressure used for example with a foam-applicating brush for initial washing of a vehicle, an intermediate pressure for the application of chemicals through the lance, such as shampoos and wheel-cleaning agents, and a maximum pressure for vehicle rinsing. There may be advantages in controlling the motor to run at several distinct speeds, to optimise the cleaning potential -for example, the foam brush could be used at a low pressure, wheel cleaning could be performed at a slightly higher pressure, bumper cleaning at yet a higher pressure and general rinsing at maximum pressure. By using a suitable controller, the optimum pressure may be pre- programmed for whatever activity is required.

With equipment arranged to deliver three pressures as aforesaid, at the io end of a program phase the controller advantageously is arranged to decrease the power supplied to the motor from the maximum value to the intermediate value over a first period and to decrease the power supplied from the intermediate value to the low value over a second, shorter period. The first period may typically be in the range of 1 to 30 seconds and preferably about 15 seconds; and the second period may typically be in the range of 0.5 to 10 seconds and preferably about 3 seconds. Conversely, similar values may be employed when increasing the power from the low value to the intermediate value, and from the intermediate value to the maximum value. In the event the user releases the lance trigger, the power supplied to the motor may be reduced very rapidly down to the low value, typically within 0.3 seconds. Then, on re-opening the lance valve, the pressure may build up again to the maximum in accordance with a pre-set regime.

The jet-wash may be modified to allow the pump to provide pressures within the range of 40 kPa up to 10,250 kPa or thereabouts, with the very low pressure being adopted when the jet-wash is in stand-by mode. By preventing the lance trigger valve from closing fully, but allowing a very small leakage of water, and running the pump very slowly, a constant through-flow of water in the jet-wash and lance may be assured to prevent freezing, during inclement conditions. A temperature sensor may be provided to inhibit operation of the pump when in stand-by mode, in the event that there is no risk of freezing.

By way of example only, one specific embodiment of power-washing equipment of this invention will now be described in detail, reference being made to the accompanying drawings in which:-Figure 1 diagrammatically illustrates a known form of power-washing equipment able to deliver low and high pressures to an user lance; Figure 2 diagrammatically illustrates the embodiment of power-washing equipment of this invention; and Figure 3 diagrammatically illustrates the control of the motor driving the high pressure pump, in the embodiment of Figure 2.

Referring initially to Figure 1, there is shown a known form of power-washing equipment intended for use as a self-service vehicle jet-washer, for installation for example on a garage forecourt. The equipment comprises a high pressure pump 1 0 driven by an electrical motor (not shown) provided with switch gear (also not shown) for turning the motor on and off. The pump 10 draws water from a break tank 11 fed with water from a mains water supply and delivers the water under pressure to a manifold feeding a line 12. At the outlet from the pump 10 there is an automatically-operating mechanical unloader valve 13, which connects back to the inlet 14 of the pump 10. The unloader valve is arranged to be normally closed but to open when the pressure in line 12 exceeds a pre-determined value. A plurality of solenoid valves (not shown) are associated with the manifold to allow the introduction of the required chemicals to the delivered water, at the appropriate times for a selected washing program.

A by-pass pipe 1 5 is arranged across the pump 10 and unloader valve 13, that by-pass pipe including a by-pass solenoid valve 16 and an adjustable flow control valve 17, pre-set to an appropriate value. When full pressure is required, the solenoid valve 16 remains closed, but when water at a low pressure is required, the solenoid valve 16 is opened, so allowing part of the flow delivered by the pump 10 to be returned to the pump inlet 14.

Line 12 is connected through a flexible hose to a user lance 19 through a high pressure by-pass solenoid valve 20, in parallel with a fixed-flow venturi valve 21. The lance 19 includes a handle 22 and an operating trigger 23, which when squeezed opens a valve within the lance so as to allow flow out of the lance nozzle 24. When water flow under high pressure is required out of the nozzle 24, the trigger 23 is pulled and the solenoid valve 20 is opened; when water flow under a lower pressure is required out of the nozzle 24 (such as may be required when applying wheel-cleaning chemical) the trigger is pulled and the solenoid valve 20 is closed so that the flow is through the venturi valve 21.

Whether operating at high or low pressure, in the event that the trigger 23 is released so stopping flow out of the lance nozzle, the pressure in line 12 will build until the unloader valve 13 operates to relieving the loading on the pump.

The pump may also deliver flow to a foam brush 25, through a brush solenoid valve 26 and a fixed-flow venturi valve 27, permitting an appropriate flow rate for the brush. During flow to the brush with the brush solenoid valve 26 open, the high pressure by-pass solenoid valve 20 should remain closed, but the by-pass solenoid valve 16 in pipe 15 should be open.

Though not shown in Figure 1, an electrical controller is arranged to operate the motor and the various solenoid valves in accordance with a pre-set program, which may either be fixed or be user-selectable. When the jet wash is in use, the pump 10 operates at a single speed and the pressure delivered to the lance 19 or the foam brush 25 depends upon the operation of the by-pass solenoid valve 16 and also the solenoid valves 20,26.

Figures 2 and 3 show the embodiment of jet wash of this invention and like parts with those of Figure 1 are given like reference numbers; those parts will not be described again in detail here. It is to be noted that the embodiment shown in Figure 2 is much simplified as compared to that of Figure 1, in that the by-pass pipe 15 together with the associated solenoid and flow control valves are eliminated as well as the high pressure by-pass and fixed-flow venturi valves associated with the water delivery to the lance 19.

In Figure 3, there is shown an electric motor 30 driving pump 10, the outlet of which is connected directly to the lance 19 such that flow out of the lance is controlled solely by the valve in the lance operated by trigger 23, so long as the pump is being driven. Power is supplied to the motor 30 by a electrical speed controller 32 in the form of an inverter to which mains power is supplied, the controller 32 receiving a speed control signal 33 from a PLC 34.

The PLC is pre-programmed with a number of user-selectable programs input for example by way of pushbuttons 35 providing an input 36 to the PLC.

Though not shown, a feedback loop to the inverter, or possibly to the PLC, is provided and which monitors either the rotational speed of the motor or preferably the water pressure at the output from the pump.

As before, the pump 10 may be a ceramic piston pump the through-put of which, and so also the output pressure for given flow conditions, is dependent upon the rotational speed of the motor. Though the PLC could set the required speed for the motor, it is preferred for the feedback loop to monitor the output pressure of the pump and for the speed of the motor to be adjusted in order to maintain that output pressure substantially at the required value.

When the pressure at the lance 19 is to be varied, and particularly when the pressure is to be reduced from a maximum value to a lesser value or even to zero, the PLC provides a signal to the inverter such that the pressure is reduced over a user-appreciable pre-set period. For example, when the pressure at the lance is about 10,250 kPa (about 1500 psi) and the pressure is to be reduced at the end of a high pressure program phase, the speed of the motor may gradually be reduced to bring the pressure down to about 6,750 kPa (about 1000 psi) over a period of about 15 seconds. If the pressure is about 6,750 kPa (about 1000 psi) and is to be reduced to about 4,000 kPa (about 600 psi), then the pressure may be reduced over a period of a few seconds and typically 3 seconds. At the end of a program and all water flow is to be stopped, the pressure may be reduced from the instantaneous value down to zero, over a period of about 20 seconds. The PLC may provide control signals to make the motor run at any pre-programmed pressure besides those three mentioned above. In a typical application, the jet-wash may be capable of providing up to seven different pressures, and appropriate ramp-up and ramp-down times provided having regard to the change in pressure, from one program phase to the next.

In addition, the PLC may provide a signal to the inverter to increase the motor speed so as to ramp up the pressure over periods comparable to those mentioned above for reducing the pressure. For example, if about 4,000 kPa is being delivered to the lance and that is to be increased to about 10,250 kPa, io the pressure may be increased to about 6,750 kPa over about 3 seconds, and then increased to 10,250 kPa over about a further 15 seconds. Also, in the event the user releases the trigger when full pressure is being delivered, the speed of the pump may be rapidly reduced typically within 0.3 seconds so the instantaneous output pressure is about 4,000 kPa; on subsequent opening of the lance valve, the pressure may be allowed to build up from 4,000 kPa to 6,750 kPa in 3 seconds and then to the maximum pressure of 10,250 kPa, typically over a further 15 second period, as described above.

It will be appreciated that by controlling the motor speed in the above way, a user will have time to react to the changing pressure and so hold the lance in a secure and stable manner even when operating at significantly higher pressures than conventionally are employed with commercial jet-washers, with a minimal risk of the nozzle striking the vehicle body. Further, it becomes possible to deliver water to the lance or the foam brush at a chosen pressure, rather than at either one of two pressures (a low value and a maximum value) as with the known jet-washers. In the example given above, water may be delivered at 4000, 6,750 and 10,250 kPa, respectively for foam washing with the foam brush, wheel washing with chemical cleaner and rinsing. The rinsing high pressure is considerably higher than is delivered by the known jet-washers which typically operate only at 4,000 and 6,750 kPa. Despite this, the risk of the lance striking a vehicle body consequent upon the expiry of a phase of the operating program is greatly reduced.

Claims

1. Power-washing equipment comprising an electrical motor drivingly coupled to a pump, a washing lance, a flexible hose connecting the pump to the lance and an electronic controller for the electric motor, the controller being arranged to control the electrical power supplied to the motor so that when the pressure at the lance is to be reduced from a relatively high value, the reduction in pressure takes place over a user-appreciable pre-set period.

2. Power-washing equipment as claimed in claim 1, wherein the controller is arranged to control the electrical power supplied to the motor so that when the pressure at the lance is to be increased from a relatively low value, the increase in pressure takes place over a user-appreciable pre-set period.

3. Power-washing equipment as claimed in claim 1 or claim 2, wherein the controller includes an inverter arranged to supply electrical power to the motor, the inverter receiving a control signal dependent upon one of a required motor speed or a required pressure value.

4. Power-washing equipment as claimed in claim 3, wherein the control signal is supplied by a data processor pre-programmed with information concerning a sequence of operation for the equipment and the required pressures during that sequence.

5. Power-washing equipment as claimed in any of the preceding claims, wherein the controller is arranged to supply electrical power to the motor so that the pump provides water at a pressure selected from at least one of a low pressure, an intermediate pressure and a high pressure.

6. Power-washing equipment as claimed in claim 5, wherein the controller is arranged to reduce the pressure from the high pressure to the intermediate pressure over a first period of several seconds and to reduce the pressure from the intermediate pressure to the low pressure over a shorter second period.

7. Power-washing equipment as claimed in any of the preceding claims, wherein the controller is arranged to increase the pressure from the intermediate pressure to the high pressure over a third period of several seconds and to increase the pressure from the low pressure to the intermediate pressure over a shorter fourth period.

8. Power-washing equipment as claimed in any of the preceding claims, wherein the lance includes an user-controlled flow valve and when opened, the controller is arranged to increase the pressure from a lower pressure to a higher pressure over a user-appreciable pre-set period.

9. Power-washing equipment as claimed in claim 8, wherein the controller is arranged rapidly to decrease the pressure from a higher pressure to a lower pressure when the flow valve associated with the lance is closed.

10. Power-washing equipment as claimed in any of the preceding claims, wherein the controller includes a feedback loop which detects one of motor speed and pump output pressure and controls the motor speed dependent upon the detected value.

11. Power-washing equipment as claimed in any of the preceding claims, wherein there is provided a mechanical unloader valve on the output from the pump, which unloader valve is arranged to deliver water to the inlet of the pump in the event that the pressure downstream of the pump rises above a pre-determined value.

12. Power-washing equipment as claimed in any of the preceding claims, wherein there is provided a low-pressure brush connected through a solenoid valve and a pressure-restricting venturi valve to the output of the pump.

13. Power-washing equipment as claimed in claim 1 and substantially as hereinbefore described and as illustrated in Figures 2 and 3 of the accompanying drawings.

14. A method of controlling power-washing equipment having an electrical io motor drivingly coupled to a pump, a washing lance and a flexible hose connecting the pump to the lance, in which method an electronic controller for the electric motor reduces the electrical power supplied to the motor over a user-appreciable pre-set period when the pressure at the lance is to be reduced from a relatively high value.

15. A method as claimed in claim 14, in which the electronic controller for the electric motor increases the electrical power supplied to the motor over a user-appreciable pre-set period when the pressure at the lance is to be increased from a relatively low value.

16. A method as claimed in claim 14 or claim 15, wherein the controller includes an inverter arranged to supply electrical power to the motor, a control signal dependent upon a required motor speed or a required pressure value being provided to the inverter.

17. A method as claimed in claim 16, wherein the control signal is supplied by a data processor pre-programmed with information concerning the required pressure.

18. A method as claimed in any of claims 14 to 17, wherein the controller reduces the pressure from a relatively high value to a relatively low value over a period of several seconds at the end of a phase of a washing program.

19. A method as claimed in claim 18, wherein the period falls within the range of 1 to 30 seconds.

20. A method as claimed in any of claims 14 to 19, wherein the controller io supplies electrical power to the motor so that the pump provides water at a selected one of a plurality of different pressures consisting of at least a low pressure, an intermediate pressure and a high pressure.

21. A method as claimed in claim 20, wherein the controller reduces the pressure from the high pressure to the intermediate pressure over a first period of several seconds and reduces the pressure from the intermediate pressure to the low pressure over a shorter second period.

22. A method as claimed in claim 21, wherein the first period falls within the range of 1 to 30 seconds and the second period falls within the range of 0.5 to seconds.

23. A method as claimed in any of claims 14 to 22, wherein the controller is arranged to increase the pressure from a relatively low value to a relatively high value over a period of several seconds.

24. A method as claimed in claim 23, wherein the period falls within the range of 1 to 30 seconds.

25. A method as claimed in any of claims 14 to 24 and where the controller supplies electrical power to the motor so that the pump provides water at a selected one of a plurality of different pressures consisting of at least a low pressure, an intermediate pressure and a high pressure, wherein the controller increases the pressure from the intermediate pressure to the high pressure over a third period of several seconds and increases the pressure from the low pressure to the intermediate pressure over a shorter fourth period.

26. A method as claimed in claim 25, wherein the third period falls within the range of 1 to 30 seconds and the fourth period falls within the range of 0.5 to 10 seconds.

27. A method as claimed in any of claims 14 to 26 and in which the lance includes an user-controlled flow valve, wherein on closing said valve when delivering a high pressure, the controller rapidly reduces the pressure to a lower pressure, and then on the user re-opening said valve, the controller increases the pressure from the lower pressure to the high pressure over a user-appreciable pre-set period.

28. A method as claimed in claim 27, wherein the pressure is reduced to the lower pressure within a period of less than 1 second.

29. A method of controlling power-washing equipment as claimed in claim 14 and substantially as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.