| JPS62110221 | SEALED THERMOSTAT |
| JPS56110085 | BIMETAL |
MILANESE PIERANTONIO (IT)
| US3279258A | 1966-10-18 | |||
| US2838936A | 1958-06-17 | |||
| US20060013283A1 | 2006-01-19 | |||
| GB1502640A | 1978-03-01 | |||
| US2365487A | 1944-12-19 | |||
| GB531280A | 1941-01-01 |
| CLAIMS 1. Probe (7, 19, 28) for collecting data to be used in boilers (3) for the generation of steam and/or in tanks (18, 29) containing hot liquids, characterized in that it comprises at least one element made of a bimetallic material (13, 17, 20, 32, 36) suited to modify its shape according to the temperature inside said boiler or tank (3, 18, 29), and wherein said shape modification causes the mechanical detachment of the scale deposited on at least part of said probe (7, 19, 28). 2. Probe (7, 19, 28) for collecting data according to claim 1, characterized in that it comprises at least one rod (12, 30) with a terminal or lower end (71 , 121 , 34) for measuring the water level in said boiler or tank (3, 18, 29), said bimetallic element (13, 17, 20, 32, 36) being integrally inserted in said rod (12) in proximity to its end (71, 121, 34). 3. Probe (7, 19) for collecting data according to claims 1, 2, characterized in that said bimetallic element (13) has a curved shape with at least one concave area facing towards at least one side and, when the temperature inside said boiler or tank (3, 18, 29) increases or decreases compared to a predetermined value, said bimetallic element (17) changes its shape so that its concave area moves towards the opposite side, and wherein said shape modification takes place with an abrupt movement suited to cause said mechanical detachment of the scale at least from said end (71 , 121 , 34) of said rod ( 12) due to the shaking action. 4. Probe (28) for collecting data according to claims 1, 2, characterized in that said bimetallic element comprises a spiral-shaped body (32, 36) fitted on said rod (30) and a scraping disc (33) fitted on said rod (30) in proximity to said lower end (34) of the rod (30) and integral with the lower end (321) of said spiral-shaped body (32, 36), and wherein when the temperature inside said boiler or tank (3, 18, 29) increases or decreases compared to a predetermined value said spiral-shaped body (32, 36) extends or contracts causing the corresponding shifting movement of said scraping disc (33) that, acting at least on said lower end (34) of said rod (30), mechanically removes the scale deposited on it. 5. Probe (28) for collecting data according to claim 4, characterized in that said spiral-shaped body (32, 36) is a form memory body, and wherein when the temperature value increases compared to said predetermined temperature value said spiral-shaped body (32, 36) extends, while when the temperature value decreases compared to said temperature value said spiral-shaped body (32, 36) returns to its original shape and brings the scraping disc (33) to the rest position, spaced from the end (34) of said rod (30). 6. Probe (7, 19, 28) for collecting data according to claims 2, 3 or 4, 5, characterized in that said shape modification of said bimetallic element (13, 17, 20, 31 , 36) takes place at temperature values near 50 °C. 7. Probe (7, 19, 28) for collecting data according to one or more of the preceding claims, characterized in that said rod (12, 30) of said probe (7, 19, 28) is at least partially covered by a pipe or covering (14, 23, 31) that protects said rod (12, 30) from the formation of scale and is also suited to insulate it from said boiler or tank (3, 18, 29). |
DATA COLLECTION PROBE FOR LIQUID TANKS SUBJECT TO SCALE
FORMATION
The present patent concerns a new self-cleaning thermal resistive probe for data collection, to be used in tanks and/or boilers for steam generation which are subject to scale formation.
Even if not exclusive, the innovation finds particular application in equipment using liquids at high temperatures or steam generators for performing their functions whether in domestic or industrial environments, for example ironing systems, coffee machines, cleaning machines, pressure washers, hydrojets, combined vacuum cleaners, etc.
The current state of the art includes known water level probes which transmit an electrical resistivity and/or temperature signal. Said probes work perfectly until they are covered by scale deposited inside the tank or boiler. In fact, the terminal of these probes is exposed to the wet-dry cycle of the water level that generally exceeds 50 degrees Celsius, in which conditions the terminal is covered by scale very quickly and the probe is no longer able to transmit the water level signal properly as it is insulated by the scale deposited on its surface.
There are also self-cleaning systems for said probes where the water inlet is placed directly on the probe to wash the scale depositing on the probe itself. Indeed, this system does not solve the problem, either, because it just extends the proper functioning of the probe a little longer, as the scale is formed anyway.
The above results in frequent and expensive servicing and inconvenience for the users. The object of the present invention is to completely overcome these problems, making the equipment always efficient and completely eliminating the burden of servicing the piece, virtually with no additional cost.
The patent consists of a self-cleaning probe driven by the temperature variation of the probe itself or the tank to which it is applied.
Depending on the application requirements, the new probes operate according to two operating methods, by so-called mechanical shock and/or by the extension of memory form materials.
The terminal in contact with the water of the new probe operating based on the thermal shock method is equipped with a bimetallic disc firmly fixed to the metal rod of the probe itself, preferably featuring a convex shape and suitably designed with respect to its size and triggering temperature. Said disc operates through a snap-bending action, and every time the temperature exceeds 50°C, for example, the disc abruptly snaps from a convex to a concave shape; as a result of the abrupt movement or mechanical shock, the scale deposited around the disc in the prior phases of the operation of the boiler is removed by detachment, leaving the surface of the disc perfectly free of scale deposits. When the power is turned off and the temperature drops below 50°C, the same mechanical reaction is repeated, that is, the bimetallic disc snaps from the position assumed as a result of the increased temperature of the previous phase, from the convex to the concave shape by the effect of the decreasing temperature, once again eliminating any remaining scale deposited on the disc surfaces.
This system guarantees continuous contact between the water and the probe, given that no insulation layers can be formed due to scale deposits. By way of a non-limiting example of the characteristics of the present invention, one example of embodiment of the system based on the mechanical shock method is described below with reference to the attached schematic drawings shown in Figures 1- 4.
Figure 1 shows the system as a whole in an automatically refilling water boiler. It consists of a cold water tank (1), a water pump (2) to supply the boiler, a boiler (3), a corresponding heating element (4), a probe (7) for the control of the water level in the boiler, a signal wire (8) suited to send a signal to the electronic card, a solenoid valve (9) for steam release, a pressure switch (10) and an electronic card (11).
When the equipment in turned on, if the water level (5) does not reach the terminal (71) of the probe (7), the pump unit (2) turns on, controlled by the electronic card (11), and said pump (2) draws the water from the tank (1) and feeds it into the boiler (3) until the water level (6) reaches the probe (7).
The probe (7), by means of the signal wire (8), sends the signal confirming that the water level has reached the probe to the electronic card (11) which commands the shutdown of the pump (2). The heating element (4), following the impulse received from the electronic card (11), heats up and boils the water in the boiler and when the steam reaches the predetermined pressure the pressure switch (10) shuts off the heating element (4). The steam for use is drawn out through the solenoid valve (9). Through the use of steam, the water level drops below the level of the probe (7) breaking the contact with the water. Thus a signal is sent to the electronic card (11) that starts the cycle again, as above.
Figure 2a shows an overview of the probe (7) operating based on the mechanical shock method, consisting of a metal rod (12), an element made of a bimetallic material (13), a pipe made of material which insulates and protects the rod from scale (14), a signal wire suited to send a signal to the electronic card (15), tapered screw elements (16) to fasten it on the walls of the boiler (3).
The element made of a bimetallic material (13) is fixed to the rod (12), preferably to its lower end (121), so as to be integral with it, and at an ambient temperature, for example about 25°C, has a concave shape. The rod (12) is covered by an insulating element (14) that protects it from scale and insulates it from the boiler.
Figure 2b shows the same probe (7) where, in the presence of a temperature exceeding 50°C, for example, the element made of a bimetallic material (17) assumes a convex shape.
Figures 3 and 4 show the boiler-level probe assembly.
Figure 3 shows the application of the level probe (19) to a tank (18) with liquid at an ambient temperature of approximately 25°C, that is, before the equipment is turned on. In this condition, the element made of a bimetallic material (20) maintains the concave shape. The level probe (19) is inserted in the tank (18) and is insulated from the boiler by a pipe or insulation element (23) and attached to the boiler itself with tapered screw elements (22).
Figure 4 shows the same boiler-level probe assembly where the element made of a bimetallic material (20) is in a convex shape as the water temperature exceeding 50°C owing to the action of the heating element (24) triggers it provoking an abrupt movement from the concave position to the convex position, thus causing a mechanical shock which detaches any scale that may have formed there.
Upon switching off of the equipment, when the temperature drops below 50°C, the element made of a bimetallic material (20) changes from a convex to a concave form, a change which takes place abruptly, leading to the detachment of the scale that may have formed again as a result of the shaking action.
Since the sequence described above occurs each time the equipment is used, both on heating and cooling, the probe (19) is constantly kept clean ensuring data transmission to the electronic card by contact with the water, as there is no longer the risk of insulation due to scale deposits.
Another embodiment of the invention is illustrated in Figures 5 and 6, showing a schematic view of the probe (28) assembled in a tank (29). In this case the probe (28) comprises a rod (30) and is equipped with a bimetallic element comprising a spiral- shaped memory form body (32) fitted on said rod (30), the lower end (321) of which is integral with a scraping disc (33), which is also fitted on said rod (30) near its lower end (34). The probe (28) is insulated from the tank (29) and the spiral body (32) by a pipe or coating of insulating material (31).
At an ambient temperature below 50°C the spiral-shaped memory form body (32) keeps the scraping disc (33) in the resting position, that is, at a distance, for example about 5 mm, from the end (34) of the rod (30) of the probe (28).
Figure 6 shows the tank with a temperature above, for example, 50°C. The spiral- shaped memory form body (36), due to the temperature above 50°C, will extend its helical shape and move the scraping disc (38) to the end of the rod (37), causing the scraping of the rod (37) itself. The scale which has formed on the rod (37) will be removed completely.
When the equipment is turned off the temperature in the tank will drop below 50°C and the spiral-shaped memory form body (36) will return to its original position, bringing the scraping disc (38) back to its original position, performing the scraping action in the opposite direction and thus once again cleaning the scale deposited on the terminal of the rod (37) of the probe (28).
This embodiment also guarantees the complete cleaning of the probe from scale every time the equipment is turned on and turned off, making the signal indicating the liquid level that is sent to the electronic card of the equipment reliable over time.