GB2243992A

GB2243992A - Solvent extraction carpet-cleaning machine

Info

Publication number: GB2243992A
Application number: GB9109414A
Authority: GB
Inventors: Geraint Lloyd Owens; Timothy Morris Owens
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-05-04
Filing date: 1991-05-01
Publication date: 1991-11-20
Also published as: GB9010133D0; DE9105512U1; IT1245484B; GB9109414D0; ITTO910325A0; ITTO910325A1

Abstract

A solvent extraction carpet-cleaning machine comprises: a pump 47 for pumping cleaning fluid to a spray nozzle; a vacuum system 45, 46 for extracting the cleaning fluid and dirt from the carpet; a controller 30 for controlling operation of the pump 47 and the vacuum system (45, 46); and a control panel 3, 4, 5 operatively connected to the controller (30) for sending control signals thereto and for providing a visual display 5 in response to indicator signals from the controller 30, said control panel being a low voltage control panel 3, 4, 5 operating at voltages of less than 20 volts. <IMAGE>

Description

SOLVENT EXTRACTION CARPET-CLEANING MACHINE Field of the Invention This invention relates to solvent extraction carpet-cleaning machines, and more particularly, but not exclusively, to hot water extraction carpet-cleaning machines.

Current solvent extraction carpet-cleaning machines typically make use of mains operated mechanical switches and gauges in the control panels by which the user operates the machine. This requires wiring at mains voltages to be connected to the panel, providing problems with water sealing and with ease of construction and reliability, since mechanical switches operating at mains voltages (for example 120V or 240V AC), are subject to wear, over heating and arcing. The combination of use of solvent, or cleaning fluid, (usually an aqueous solution of detergent and other chemicals) with high voltage manually operated switches creates a substantial operator safety risk. To the best of the applicant's knowledge no known solvent extraction carpetcleaning machines satisfactorily overcome this problem.

It is a general objective of the present invention to improve operator safety of such machines.

Summary of the Invention According to the present invention there is provided a solvent extraction carpet-cleaning machine which comprises: a pump for pumping cleaning fluid to a spray nozzle; a vacuum system for extracting the cleaning fluid and dirt from the carpet; a controller for controlling operation of the pump and the vacuum system; and a control panel operatively connected to the controller for sending control signals thereto and for providing a visual display in response to indicator signals from the controller, said control panel being a low voltage control panel operating at voltages of less than 20 volts.

Preferably the controller is a microprocessor.

Preferably the control panel has a continuous heat-formed plastics membrane sealing the electronic circuitry of the control panel externally of the machine, in use, from moisture.

Preferably the control panel has a continuous heat-formed plastics membrane sealing the electronic circuitry of the control panel internally of the machine, in use, from moisture.

Preferably the control panel incorporates touch-sensitive switches for generating said control signals.

Preferably the control panel visually displays indicator signals on alpha-numeric arrays of light-emitting diodes (LED's).

Preferably the machine is provided with solid-state sensors which detect the cleaning fluid's temperature and pressure and the vacuum pressure.

Where the controller is a microprocessor, the microprocessor may be programmed to scan the said signals sequentially and to signal the control panel accordingly.

The control programme may be used to sequence the operation of the pump and vacuum system and, where present, the heater.

The machine of the present invention has greater reliability than conventional machines, having no moving parts in the controller, and no manually operated switches switching mains voltages and, therefore, liable to failure through over heating or arcing. By removing mains voltages from the control panel, safety is greatly increased, and the control panel can be more readily sealed against ingress of liquid.

Brief Description of the Drawings The drawings show a preferred embodiment of the invention. In the drawings: Figure 1 is a perspective view of the machine; Figure 2 shows the layout of the control panel of the machine of Figure 1; and Figure 3 is a block diagram of the main functional components of the machine shown in Figure 1.

Description of the Preferred Embodiment Referring first to Figure 1, the machine comprises a wheeled body 1 containing a water tank provided with a heating element, a pump to pump water from the tank to a supply hose (not shown), and a waste receiving tank to which is connected a vacuum pump, and from which leads a suction hose (not shown). The supply and suction hoses lead to a cleaning head. In these components, the machine is conventional. At the front part of the body 1 is mounted a control panel 2. This has a continuous heat-formed polyester membrane sealing the components beneath from moisture and printed to define the switch and instrument portions, as illustrated in Figure 2.The panel 2 is positioned so as to be readily accessible to the operator, and incorporates high-intensity light-emitting diode (LED) displays for high reliability and for ready viewing under high ambient light conditions, for example as typically found in modern offices.

As may be seen from Figure 2, the control panel 2 is laid out to provide two sets 3 and 4 of controls and a set 5 of displays. The first set 3 of controls comprises four pairs of touch switches, each pair providing an "on" and an off switch, providing a start signal and a stop signal respectively. The pairs of switches control the following functions: water pump (3a), first vacuum pump (3b), second vacuum pump (3c) and heater (3d).The second set 4 of controls consists of six touch switches 4a to 4f for selecting the desired water temperature, at pre-set levels of 50 60 , 65 , 70 , 75 and 80 , the latter two being separated by indicia on the panel to indicate that these temperatures should only be used with caution. The displays 5 comprise seven-segment LED arrays to permit the display of pump pressure (5a), water temperature (5b), receiving tank vacuum (5c) and the cumulative running time of the vacuum motors (5d). The pre-set water temperature levels permit the water temperature to be selected to suit the materials and cleaning requirements.The temperature is selected by pressing the heater "on" switch 3d, followed by the temperature pre-set switch 4 according to the temperature selected.

Referring now to Figure 3, the machine is controlled by an 8-bit CMOS micro-controller 30 incorporating three timers and four 8-bit input/output (I/O) ports. These ports are connected respectively to the displays 5, to the sets 3 and 4 of control switches, and to a multiplexer 31 and analogue-to-digital converter 32 receiving and converting signals from vacuum 33, pressure 34, and temperature 35 sensors via respective amplifiers 36, 37 and 38. A stabilised power supply 39 provides power for the sensors and associated circuitry. The fourth port connects to solid state relays 40 to 43, respectively controlling the supply of mains power to the heater 44, the first vacuum pump 45, the second vacuum pump 46, and the water pump 47. A separate power supply 48 is provided for the micro-controller 30.

The seven-segment LED displays are refreshed with data processed by the micro-controller and driven asynchronously by separate display drivers (not shown). Information from the pressure, vacuum and temperature sensors 33, 34, and 35, is amplified by the respective amplifier 36, 37 or 38, and multiplexed by the multiplexer 31 to the analogue-to-digital (A/D) converter 32. The micro-controller polls the sets 3 and 4 of control switches and the A/D converter 32 at different frequencies to maximise the response from the switches 3 and 4. The outputs to the pumps and heater are sequenced by the micro-controller to minimise loading on the mains inputs and to prolong their life.

Information from the temperature sensor 35 is used to control the energy input to the heater so that the water temperature is maintained at the predetermined set point.

The status of the pumps and heater is maintained in a memory register in the micro-controller and is compared with input from the control switches 3 and 4. On receipt of a request resulting in a change of status, the appropriate signals are sent through an I/O port to the solid state relay 40, 41, 42 or 43, to switch the pump or heater on or off. The same register is used to determine the status information displayed by the display 5, for example the temperature set point.

The total run time recorded by the vacuum motors is stored in a non-volatile memory in increments of 5 minutes.

This information is maintained for ten years without further energisation. The memory is also used for various "housekeeping" functions. Thus, information may be stored which may be useful in determining when the machine needs servicing (for example to replace brushes in the water pump motor or the vacuum motors) or to monitor how much time has been spent on every job for which the machine is employed.

The switches 3 and 4 are scanned in blocks to determine quickly if an alteration to machine status is requested; this together with the tactile response gives feedback to the user that the request has been captured and allows the micro-controller 30 to determine the most suitable course of action. Priority is given to the water pump 47, vacuum motors 45 and 46, and heater 44, in that order.

The use of two stabilised power supplies 39 and 48 allows the system, in the event of a power failure, to fail safe, and provides some immunity to the measurement circuitry from electrical noise generated by the pumps and heater.

It will be appreciated that references to "water may also be taken to include cleaning solutions.

Claims

1. A solvent extraction carpet-cleaning machine which comprises: a pump for pumping cleaning fluid to a spray nozzle; a vacuum system for extracting the cleaning fluid and dirt from the carpet; a controller for controlling operation of the pump and the vacuum system; and a control panel operatively connected to the controller for sending control signals thereto and for providing a visual display in response to indicator signals from the controller, said control panel being a low voltage control panel operating at voltages of less than 20 volts.

2. A machine as claimed in claim 1, wherein the controller is a microprocessor.

3. A machine as claimed in claim 1 or 2, wherein the control panel has a continuous heat-formed plastics membrane sealing the electronic circuitry of the control panel externally of the machine, in use, from moisture.

4. A machine as claimed in any preceding claim wherein the control panel has a continuous heat-formed plastics membrane sealing the electronic circuitry of the control panel internally of the machine, in use, from moisture.

5. A machine as claimed in any preceding claim wherein the control panel incorporates touch-sensitive switches for generating said control signals.

6. A machine as claimed in any preceding claim wherein the control panel visually displays indicator signals on alpha-numeric arrays of light-emitting diodes (LED's).

7. A machine as claimed in any preceding claim wherein the machine is provided with solid-state sensors which detect the cleaning fluid's temperature and pressure and the vacuum pressure.

8. A machine as claimed inlclaims 2/wherein, the microprocessor is programmed to scan the said signals sequentially and to signal the control panel accordingly.

9. A machine as claimed in any preceding claim wherein the machine further comprises a heater for heating the cleaning fluid and the controller controls the operation of the heater.

10. A machine as claimed iniclaims 2!wherein the microprocessor is programmed to sequence the operation of the pump and vacuum system and, where present, the heater for heating the cleaning fluid.

11. A machine substantially as described herein with reference to the accompanying drawings.