| JPH0734981 | [Name of device] Mat hanger |
| JPS5218069 | AUTOMOBILE WASHING DEVICE |
DE SILVIO MARCELO ELVIO (IT)
| WO2008125456A2 | 2008-10-23 |
| US20040159342A1 | 2004-08-19 | |||
| US20040220817A1 | 2004-11-04 | |||
| EP0309004A2 | 1989-03-29 |
| CLAJMS
1. Washing process in an automatic vehicle washing plant, characterised in that it comprises a step of detecting the environment temperature at the time when the washing cycle is carried out and a subsequent dosaging step of the chemical products in the washing and/or finishing agents with a correlation law with the environment temperature value detected so as to keep the washing efficiency unchanged as said environment temperature varies .
2. Washing process in an automatic vehicle washing plant according to claim 1, characterised in that said correlation law between said detected environment temperature and the concentration of the chemical products in the washing agents is of the inverse type.
3. Washing process in an automatic vehicle washing plant according to the previous claim, characterised in that said correlation law is specific for each chemical product.
4. Washing process in an automatic vehicle washing plant according to one or more of the previous claims, characterised in that the control unit of said plant receives in input said detected environment temperature value and generates in output a specific activation signal of the dosaging pump of each specific chemical product that intervenes in the washing cycle, determined for each chemical product by its correlation law and by said detected environment temperature value.
5. Washing process in an automatic vehicle washing plant according to one or more of the previous claims, characterised in that said correlation law is programmable and modifiable by the operator.
6. Washing process in an automatic vehicle washing plant according to one or more of the previous claims, characterised in that said signal is in the form of selection of the pulsation frequency of said dosaging pump to have the dose of each chemical product determined by its specific correlation law and by said detected environment temperature value .
7. Washing process in an automatic vehicle washing plant as described and claimed. |
WASHING PROCESS IN AN AUTOMATIC VEHICLE WASHING PLANT
DESCRIPTION
The present invention refers to a washing process in an automatic vehicle washing plant.
As known, the washing quality is influenced by multiple factors including in particular the chemical washing and finishing agents.
The behaviour of the chemical washing and finishing agents depends upon the temperature at the time when they operate .
The temperature value adequately represents at the same time both the thermal conditions of the washing water and those of the bodywork of the vehicle.
The reactivity of the chemical products (emollients and shampoos for washing and waxes, brighteners and polishes for finishing) and consequently the quality of the wash and finish is therefore influenced by the temperature.
The kinetics of the chemical reaction depends upon the temperature and the quantity of product present; therefore, to compensate for the variation in temperature it is necessary to modify the dose.
In particular, given the aggressiveness of the emollients, it could be that a suitable quantity at a low temperature becomes harmful at a high temperature .
With more than 10° of variation it can be appreciated that there will be a change in the quality of the treatment.
In order to compensate for this the calibration of the doses must be modified: increasing with low temperatures and decreasing with high ones.
This adjustment is normally carried out between summer and winter but not over the period of one day.
Moreover, the number of products currently used in top of the range washing facilities constantly increases and currently it is possible to have an average of 6 to 8 different products and a maximum of 12. This also greatly complicates the seasonal adjustments.
It should also be noted that in the natural shift in temperature when passing between summer and winter, during a single season and in particular spring and autumn there can be a substantial temperature shift over a single day (even of more than 1O 0 C) .
Due to all of the above, there is a tendency to leave a fixed calibration that means a variation in the washing quality and/or a waste of chemical product, if not actually a risk of damage to the bodywork of the vehicles .
The waste of chemical products also influences the treatment of the wastewater (purification) .
The technical task proposed of the present invention is, therefore, to make a washing and finishing process in an automatic vehicle washing plant that allows the aforementioned technical drawbacks of the prior art to be eliminated.
In this technical task, a purpose of the invention is to make a washing and finishing process in an automatic vehicle washing plant that improves the washing and finishing quality for different climatic conditions.
Another purpose of the invention is to make a washing and finishing process in an automatic vehicle washing plant that optimises the consumption of washing and finishing chemical products .
The last but not least purpose of the invention is to make a washing and finishing process in an automatic vehicle washing plant that is extremely effective without the risk of damaging the vehicles subjected to treatment.
The technical task, as well as these and other purposes, according to the present invention, are accomplished by- making a washing and finishing process in an automatic vehicle washing plant according to claim 1.
Other characteristics of the present invention are defined, moreover, in the subsequent claims.
Further characteristics and advantages of the invention shall become clearer from the description of a preferred but not exclusive embodiment of the washing and finishing process in an automatic vehicle washing plant according to the finding, illustrated for indicating and not limiting purposes in the attached drawings, in which:
- figure 1 shows a control scheme of the dose according to the environment temperature.
With reference to the quoted figure, a control scheme of the washing process in an automatic vehicle washing plant is shown in which a correlation law between the concentration of the chemical products present in the washing agents and preferably in the finishing agents during the washing cycle, and the environment temperature value detected when said cycle is carried out is established.
The correlation law (and its parameters) is different for each specific chemical product; this parameter breakdown is available to the manager of the plant to further adjust the doses to the type of product used.
The washing plant comprises a unit 1 for washing vehicles 7 managed by a control unit 2 that can be programmed by the operator through a suitable control panel 3.
The washing plant foresees a water line 5 for feeding the dispensers of the unit 1 and a dosaging system 4 having a plurality of tanks a, b, ...n, containing respective chemical products for washing (emollients and shampoos) and for finishing (waxes, brighteners and polishes) .
Each tank a, b, ...n is equipped with a respective dosaging pump suitable for injecting the chemical product into the water line 5 to form a washing or finishing agent with the suitable concentration of chemical product.
The washing unit 1 can be of whatever type, using a tunnel or one or more fixed or mobile portals, with or without brushes.
A temperature probe is also connected to the control unit to
detect the environment temperature .
The programmable control unit 2 allows the correlation laws and the parameters that determine the variations in dose with respect to the detected environment temperature to be set.
In this way, during the washing cycle, the control unit 2 adjusts the dispensing of each chemical product according to the environment temperature and in conformity with the correlation law and the parameters programmed for it.
Preferably, in the washing plant in which it is wished to implement this innovation the control unit 2 consists of a PLC (Programmable Logic Controller) device with analogue input for the temperature probe, the dosaging pumps are of the variable frequency impulse type, and the control panel 3 is an electronic panel with a keypad and display for data insertion.
The washing process according to the invention is clear from what has been described and illustrated and, in particular, it is substantially the following.
The PLC controls all of the functions relative to the washing cycles and detects the environment temperature value through the suitable temperature probe. In every step of the washing (and finishing) cycle, the PLC makes the respective dosaging pump pulsate at the correct frequency to dose in each washing agent and in each finishing agent a quantity of chemical product that is determined by the specific correlation law set and by the detected environment temperature value. The
parameters relative to the correlation laws can be inserted or modified using the operator panel.
Hereafter we display a way of calculating the correlation between environment temperature and concentration of the chemical product in the washing agent .
The active chemical product contained in a washing agent acts upon dirt with a real chemical reaction that allows the dirt to be dissolved and subsequently removed by the mechanical action of brushes and water.
Like all chemical reactions, these can also be characterised by suitable reaction kinetics .
Referring to the surfactant as R-A and the molecule of dirt present on the surface to be washed as B, the reaction attacking the dirt can be summarised as:
R-A + B + H2O → R-B + A + H20
In which substance A is more soluble in water than substance B, whereas substance R-B is at the same time more soluble than substance B.
Let us define the variation in molar concentration of each of the substances involved in the reaction over time as "reaction rate v" :
v=-d(R-A) /dt=-d(B) /dt=d(R-B) /dt=d(B) /dt=dξ/dt
(1.1)
where ξ is the stage of progression of the reaction.
The reaction rate is often proportional to the concentration of the components involved in the reaction, through the equation:
V=k I R-A I a * I B I b (1.2)
Where a and b are determined experimentally by are in any case positive, whereas the rate constant k, also determined experimentally is still associated with the temperature of the Arrhenius equation:
K=Ae (-Ea/RT)
(1.3)
In which Ea is the activation energy of the chemical reaction, and R is the universal gas constant.
An increase in temperature thus means an exponential increase in the rate constant k, and consequently, for the same concentration of substances involved, in the reaction rate. At the same time, by keeping the rate constant it follows that as the temperature increases the concentration of reactants suitable for ensuring the same v increases.
EXAMPLE :
Given the complexity of composition of the surfactant mixtures used in washing, it is not simple to attribute precise values to the constants shown above, but with suitable simplifications we can find a correlation between temperature and concentration of active agent.
The simplifications concern:
the reaction kinetics that for the sake of simplicity shall be considered of the first order, which implies attributing the value 1 to the constant a; the concentration of solid substance "dirt" representing for all purposes a second step to the chemical process shall be considered unitary in the equation 1.2;
for the activation energy of the chemical reaction in object, an average value of 20 KJ/mol should be considered representative; and
the frequency factor A for a reaction of the first order can be taken with a magnitude equal to 10 10 sec "1 (literature) .
R 8.314 J/mol 0 K
Ea 20000 J/mol
1000000000
A 0 sec-1
V
According to formulae 1.2 and 1.3 it is thus demonstrated that the reaction rate depends linearly upon the
concentration and exponentially upon the temperature.
The empirical data tells us that this law of variation, for the operating temperature range of the wash (5-35 0 C) , gives a variation of the reaction rate of between 50 and 100% of the maximum obtainable value at 35 0 C; this means a reduction of about 50% in washing efficiency at the minimum temperature.
This data allows us to demonstrate the proposed innovation, since it can be seen that by acting in the opposite way upon the concentration of the chemical product it is possible to compensate for the effect of the temperature and thus keep the washing efficiency constant. In the example outlined, it can be seen that by varying the concentration from 50% to 100%, it is possible to compensate for a temperature decrease of 3O 0 C, which is perfectly obtainable with the normal dosaging systems present on the plant .
The washing process thus conceived can undergo numerous modifications and variants, all of which are covered by the inventive concept; moreover, all of the details can be replaced by technically equivalent elements.
In practice, the materials used, as well as the sizes, can be whatever according to requirements and the state of the art.