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(11) | EP 0 978 329 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Steam and water washing device |
| (57) A washing device using steam and high pressure water comprises a water tank (2),
a boiler (1) for generating steam, a washing handgrip (4) and an electronic control
unit (13) which controls, according to the signals coming from sensors (8,11) and
coming from control means (24,25) incorporated in the handgrip (4), the operation
of the whole washing device and in particular holding of correct values of temperature
and pressure in the boiler (1). |
[0002] In particular the invention refers to an electronic control system which controls the operation of a washing device provided with a resistor heated boiler for generating steam.
[0003] A washing device of said type is disclosed for example in European Patent Application EP 0 832 696, in the name of the same applicant.
[0004] The electric heated boilers used for generating steam need, for a proper operation, a very accurate control of the water level and of the temperature and steam pressure values.
[0005] The level regulators for liquids used in boilers are normally provided with two probes, a first one for the minimum level and a second one or the maximum level, and commutate an electric contact or a relay when the minimum or maximum level is reached.
[0006] The electric contact actuates alternatively a pump for pumping water into the boiler or the resistor for heating the water, so that, for safety, the resistor is always switched off when the water level is below the minimum level or the boiler is filling.
[0007] Therefore a safety operation is always guaranteed, although using a reduced number of components.
[0008] However this kind of control, which is suitable for large boilers having a steam reservoir allowing a high performance continuous operation, is very limiting if used in small boilers.
[0009] In fact, during the filling operation of the boiler, when resistor is switched off, such a quantity of cold water enters in the boiler that the steam pressure immediately falls down, interrupting machine operation.
[0010] A first object of the present invention it is therefore to provide a washing device having a boiler provided with a full electronic control which allows, at low costs, to reach high performances, normally typical of larger washing devices.
[0011] Moreover, thanks to the full electronic control, it is possible to control the device through a remote control, placed for example on a washing handgrip.
[0012] The above and other objects are reached by the washing device realised according to the invention, as claimed in the accompanying claims.
[0013] The washing device according to the invention can advantageously be used in all applications wherein it is necessary to have available a high and continuous washing capacity, therefore without interruptions during operation, still maintaining reduced dimensions and costs.
[0014] The aforesaid and other objects of the invention will become more evident from the description of a preferred embodiment with reference to the attached drawings in which:
Figure 1 is a schematic view of a first embodiment of a steam and water washing device according to the present invention;
Figure 2 is a schematic view of a second embodiment of a steam and water washing device according to the present invention; and
Figure 3 shows, in a block diagram, an electronic control unit for a washing device realised according to the present invention.
[0015] With reference to figure 1 will be described a pressure steam and water washing device according to a first embodiment of the present invention.
[0016] A boiler 1 for producing steam is provided with an electric heating resistor 12, pressure and temperature sensors 11, a water level sensor 8 and a solenoid valve 28 for controlling the steam outlet.
[0018] A washing handgrip 4 receives the steam from the boiler 1 through a first flexible tube 5 and receives, through a second flexible tube 6, a washing liquid forced by a second electric pump 7, coming from a second tank 27. The tank 27 can therefore contain whichever washing liquid, separately from the main container 2 which always contains water.
[0019] The handgrip 4, provided with a nozzle as the steam outlet and with a nozzle for washing with a liquid under pressure, further comprises control means 24, 25 for selecting various functions or operating programs for the device.
[0020] An electronic control unit 13, to which are connected all the electric connections of the device, schematically shown in Figure 1 as short dashes lines, controls the operation of the washing device, according to the signals coming from sensors and to commands received by control means 24, 25.
[0021] The control means integrated in the handgrip comprise a rotating switch 24, coupled to a control roller operable from the outside of the handgrip, for selecting various washing types or programs, and a switch or a push button 25 for enabling/disabling the desired function.
[0022] For example it is possible to select the exit of only steam, of only water under pressure, or to select the various types of detergent to be mixed with water, or again to combine the action of steam and water together.
[0023] The control means 24, 25 can be connected to the control unit 13 by means of a plurality of electric conductors, or, preferably, by means of radio-control circuit, incorporated into the handgrip 4, which transmits coded radio signals to a receiver coupled to the electronic control unit 13.
[0024] The main functions of the control unit 13 are therefore to maintain constant the water level, the temperature and the pressure into the boiler, to activate the solenoid valve 24 for the steam exit and activate the electric pumps 3 and 7.
[0025] The probe 8, used for detecting the water level in the boiler, comprises two rods, a short one 9 and a long one 10, corresponding respectively to maximum and minimum levels allowed in the boiler, which are connected to corresponding signal inputs of the control unit 13.
[0026] The signal coming from the short rod 9 is used by the unit 13 for activating the electric pump 3, immediately restoring the correct level when the water goes down that level.
[0027] In this way the water level is maintained always constant and are never introduced such water quantities which could lower excessively the boiler internal temperature.
[0028] Contemporaneously the heating resistor 12 is never switched off during the filling operation, because safety is assured by the second rod 10.
[0029] In fact, only if the water level falls under the level of the second rod 10, the resistor 12 is switched off and the operation of the device is halted.
[0030] As a further protection the main tank 2 is provided with a sensor 23, connected to the electronic control unit 13, which detects the presence of water in the tank and allows to interrupt the operation of the device if the water is missing.
[0031] The sensor 11 is a pressure and/or temperature sensor for the steam in the boiler and allows to the control unit 13 to maintain said values constant, switching on or off the resistor 12, during the normal operating phases of the device.
[0032] The secondary tank 27, for safety, is as well provided with a sensor 26, which allows the control unit 13 to inhibit the operation of the second electric pump 7 in case of absence of liquid in the tank, and to advise the operator with an acoustic/lighted signal.
[0033] In figure 2 it is shown a second embodiment of the steam and water washing device according to the present invention.
[0034] The device of figure 2 differs from the device described above only in the secondary tank which contains the washing detergent liquid.
[0035] In this second embodiment in fact the washing liquid, forced by the second pump 7, is obtained mixing the water coming from the main tank 2 with a concentrated detergent contained in a suitable small tank 14.
[0036] The detergent inflow is controlled by the electronic control unit 13 by means of a solenoid valve 17.
[0037] Two further tanks 15 and 16, having small dimensions, can contain other types of detergent, so allowing various washing kinds simply selecting the desired program on the handgrip 4 controls.
[0038] The tanks 15 and 16 are also provided with solenoid valves 18, 19 controlled by the control unit 13.
[0039] All three tanks 14, 15 and 16 moreover are provided with sensors 20, 21 and 22 which detect the absence of detergent activating an alert signal.
[0040] The main tank 2 in this case must contain more water and must be consequently larger compared to that of figure 1.
[0041] This second embodiment allows to have more flexibility in washing cycles maintaining unchanged the overall dimensions of the device.
[0042] Figure 3 shows a block diagram of the control unit 13 together with the sensors and the main electrical parts connected thereto.
[0043] All the sensors used in the device are connected to an input buffer 31 which transfer the corresponding signals to a micro-controller 30 comprising a processing unit or CPU, non volatile memories containing program instructions and RAM memories.
[0044] The signals coming from the micro-controller 30 are transferred to a power interface 32 which controls directly, by means of electronic power switches, the resistor 12, the pumps 3 and 7 and the solenoid valves 17, 18, 19 and 28.
[0045] The control unit 13 can also be provided with one or more auxiliary power outputs suitable for controlling devices external to the washing device but frequently used during washing operations. For example it is possible to activate, by means of the handgrip controls and therefore without interrupting the washing operation, a liquid aspirator or similar suction devices.
1. Washing device using steam and high pressure water, comprising:
at least a main tank (2) for water,
a boiler (1) for generating steam having an electric heating resistor (12), pressure and temperature sensors (11), water level sensors (8), and a solenoid valve (24) for controlling the steam outlet,
a first electric pump (3) for transferring water from the main tank (2) to the boiler (1),
a washing handgrip (4) connected by means of flexible tubes (5, 6) to the boiler (1)
for receiving steam and to a second electric pump (7) for receiving water under pressure,
characterised in that it comprises an electronic control unit (13) which controls,
according to the signals coming from said sensors and coming from control means (24,
25) placed remotely from the unit itself, the operation of the whole washing device
and in particular holding of correct values of temperature and pressure in the boiler,
the operation of said solenoid valve (24) for steam outlet and the operation of said
electric pumps (3, 7).
2. Washing device according to claim 1, wherein said control means (24, 25) are incorporated
in said handgrip (4).
3. Washing device according to claim 2, wherein said control means (24, 25) in said handgrip
are provided with a switch (24) for selecting various washing types or programs and
with a switch or push button (25) for activating/deactivating the selected function.
4. Washing device according to claim 3, wherein the switch (24) is a multi-position rotating
switch coupled to a control roller operable from the outside of the handgrip.
5. Washing device according to claim 2, wherein said control means (24, 25) are connected
to electronic control unit by means of a plurality of conductive electric wires.
6. Washing device according to claim 2, wherein said control means (24, 25) comprise
a radio-control circuit which transmits coded radio signals to a receiver (33) coupled
to the electronic control unit (13).
7. Washing device according to claim 1, wherein the water level sensor (8) in the boiler
comprises two rods, a short one (9) and a long one (10), corresponding respectively
to maximum and minimum levels allowed in the boiler, connected to corresponding signal
inputs of the control unit (13), and wherein the control unit activates the first
pump (3) when the water level falls below the short rod (9) while deactivates the
heating electric resistor (12) when the water level falls below the long rod (10).
8. Washing device according to claim 1, comprising a secondary tank (27) suitable for
containing a washing liquid as water or water mixed with detergent, coupled to the
suction hose of said second pump (7).
9. Washing device according to claim 8, wherein the secondary tank (27) is provided with
a sensor (26), coupled to the electronic control unit (13), which detects the presence
of liquid in the tank and allows to interrupt the operation of the second electric
pump (7) in case of lack of liquid.
10. Washing device according to claim 1, comprising one or more secondary tanks (14, 15,
16), suitable for containing various detergents, smaller then the main tank (2), coupled
by means of solenoid valves (17, 18, 19) to the outlet of the main tank (2) and to
the suction hose of said second pump (7).
11. Washing device according to claim 10, wherein the solenoid valves (17, 18, 19) of
the secondary tanks are controlled by the electronic control unit (13) according to
the control signals received from the control means (24, 25).
12. Washing device according to claim 1, wherein the main tank (2) is provided with a
sensor (23), coupled to the electronic control unit (13), which detects the presence
of water in the tank and allows to interrupt the operation of the device itself in
case of lack of water.
13. Washing device according to claim 1, wherein said electronic control unit (13) can
activate, by means of an auxiliary power output, a forced suction device.