SCOPE OF THE INVENTION

The present invention relates to a method and a unit which allow a convenient drying/cooling of soap coming from an upstream reaction plant.

PRIOR ART

At present, industrial soap production consists of at least one reaction unit and at least one drying unit. More specifically, in the reaction unit or reactor for the sake of brevity, the basic soap is produced by reaction between neutral oils or fats (or the corresponding fatty acids) and caustic soda. This unit may or may not comprise recovery equipment of the glycerin produced by the reaction (only in the case of neutral oils or fats). The basic soap, depending on the type of process used, may have a water content of 18-20% to 32-33% and even more.

In the drying unit, the basic soap, after optional preheating, is instead dried by expansion in a vacuum chamber.

The above process simultaneously cools and solidifies the soap.

The drying unit may be directly connected to the reaction unit and in this case, it is referred to as an "integrated system". The operating conditions vary depending on the characteristics of the basic soap and the specific requirements for the soap to be produced. In any case, the technique involves working under vacuum (at values of between 10 and 50 mmHg absolute) producing soaps with humidity content variable in the range from 8% to 30%.

Normally, the soap produced is extracted from the vacuum drying chamber by means of a single or multiple stage extraction drawing device, while the water vapor is passed into one or more cyclone separators to recover the fine dust that is formed during the expansion and subsequently delivered to the vacuum forming system.

With this technique, the temperature of the soap produced depends directly on the vacuum employed. It is not possible to further cool the soap, although it is desirable.

DESCRIPTION AND ADVANTAGES OF THE INVENTION

One object of the present invention is to provide an improved method and unit of drying and cooling the soap produced with a simple, rational and rather cost-effective solution.

These and other objects are achieved with the features of the invention described in the independent claim 1. The dependent claims describe preferred and/or particularly advantageous aspects of the invention.

In particular, an embodiment of the present invention involves carrying out the cooling by conductive heat exchange between the soap spread by a dedicated system and the cooling means circulating in the jacket applied outside the chamber wall.

With this solution, and in particular with the soap spreading system of the described apparatus, there is almost no formation of fine soap dust. Cyclone separators and scrubbers can thus be eliminated, thereby reducing plant costs.

In addition, it may be contemplated to partially pre-cool the soap produced exiting from the reactor through vacuum generation, where said vacuum is lower than or at most equal to that currently used.

Based on the foregoing, there is also a simplification, where required, of the vacuum system which may be formed of a simple (contact or surface) capacitor and a vacuum pump of reduced performance compared to the current ones.

Another aspect of the invention is to provide a drying apparatus provided with a jacket formed on the main body and within which a fluid, preferably water, for cooling the inner wall is kept in circulation.

With the combination of the two above solutions, there is a significant reduction in energy consumption since the first cooling, with a low degree of vacuum, does not affect the energy costs in the same way as a high vacuum system would.

According to a feature of the present invention, the inside of the cooling jacket is divided into compartments or a plurality of independent cooling chambers.

With this configuration, the cooling is more controlled as a smaller volume of water controls a corresponding portion of the chamber. According to a further embodiment, the cooling chamber, which is a vertical cylindrical body with connection to the vacuum system at the top and to an extraction drawing device at the bottom, is configured so as to comprise

- a soap dispensing system, or a rotatable dispenser apparatus, by which the soap to be cooled by heat exchange is dispensed,

- a rotatable scraper apparatus, adapted to detach, by scraping against the inner walls, the previously deposited and dried soap.

The two units, dispenser and scraper, rotate, controlled by suitable actuation means, according to the vertical axis of the cylindrical cooling chamber of the cooling apparatus.

According to a first formulation of the present invention, the apparatuses are integral with a single central shaft, which also bears the connection means for supplying the soap.

According to a possible embodiment, the dispensing and scraper apparatuses are substantially integrated into a single rotatable unit and within a particular configuration of an end thereof, as will be apparent hereinafter from the present description.

Thanks to said solution, the cooled soap can be removed at each round simultaneously depositing another layer by means of the spreading device.

Specifically, the soap is introduced from above, through a conduit that is concentric to the shaft of said wall scraper element and conveyed onto the same by means of a suitable spreading apparatus, so as to form a uniform thickness film; the cooling of which is terminated by the water circulating into the jacket.

The soap thus solidified and cooled is then detached by the scraper that will drop it into the underlying extraction drawing device.

According to a further possible embodiment, the dispensing and the scraper apparatuses are substantially independent and arranged so as to operate one in advance on the other, so that after the passage of the scraper apparatus, which removes and detaches the solidified soap from the wall, the dispenser apparatus will deposit a subsequent new layer that will be solidified before the subsequent passage of said scraper apparatus.

In this way, by maintaining the separation of the apparatuses, it is possible to provide for their independent replacement, thus reducing maintenance costs in the event of breaks or replacements of only one of the two. In addition, the rotatable system (dispenser plus scraper) is cheaper to manufacture than the integrated device already mentioned above.

The advantage, on the contrary, of having an integrated rotatable system (dispenser plus scraper) is that there will be more time available for solidifying the soap, dispensed almost in the same angular portion where the detachment of the solidified soap takes place.

Summing up, overall the advantages of the invention are:

- almost absence of fine soap dust formation; cyclone separators and scrubbers can thus be eliminated.

- simplification of the vacuum system which may be formed of a simple (contact or surface) capacitor and a vacuum pump of reduced performance compared to the current ones.

- reduction of energy consumption.

Said objects and advantages are all achieved by the method and industrial apparatus for drying soap, object of the present invention, which is characterized by the appended claims.

BRIEF DESCRIPTION OF THE FIGURES

This and other features will become more apparent from the following description of some of the configurations, illustrated purely by way of example in the accompanying drawings.

- Figure 1 : a first embodiment of the cooling unit object of the invention, implementing the claimed method,

- Figure 2: detail of the integrated dispenser and scraper cup,

- Figure 3 : a second embodiment of the cooling unit object of the invention, implementing the claimed method.

DESCRIPTION OF THE INVENTION

The invention claims above all a particular soap drying method.

Specifically, the method involves performing at least one soap cooling step by conductive heat exchange, spreading the soap on a wall of a closed chamber; it further involves circulating a cooling means in a jacket applied outside said wall of said closed chamber.

Moreover, the method also involves generating a vacuum within said closed chamber.

According to one aspect of the invention, it is contemplated to simultaneously perform the cooling by heat exchange and that by vacuum within said unit.

According to a further aspect of the invention, it is contemplated to perform a partial pre-cooling with vacuum.

Said two cooling steps being performed simultaneously within said apparatus.

In detail, vacuum cooling is preferably a partial vacuum which generates, within the drying apparatus or unit, a vacuum of between 50 and 740 mmHg absolute.

Cooling by conduction is performed on a layer or film of basic soap with substantially constant thickness; the film is deposited cyclically and continuously by a rotatable apparatus provided with dispensing nozzles. The process involves removing the film thickness deposited and dried by a scraping action.

With reference to what said about the conductive heat exchange, it should also be noted that this takes place through a separation wall of the drying unit on one side of which a cooling fluid recirculates, more precisely in an outer jacket thereof. The process described herein is carried out within a soap drying unit, substantially a vertical axis cylindrical chamber, provided with means for connecting to a vacuum generation apparatus or system therein.

The unit is also provided with at least one means, such as an extraction drawing device, for extracting the dried soap at the bottom.

The unit, on the upper portion thereof, is provided with fittings for the connection to the supply system of the soap to be dried.

The unit is also provided with suitable sealing systems adapted to ensure the partial vacuum generation therein.

The invention is articulated in providing a drying unit 1 provided with, within the cylindrical chamber 2:

a. a rotatable soap dispenser apparatus 5, configured to dispense a layer of soap 20 to be cooled by heat exchange,

b. a rotatable scraper apparatus 6, adapted to detach, by scraping against the inner walls, a previously deposited and dried layer of soap 19.

Said two apparatuses, dispenser and scraper, are rotatable coaxially to axis 7 of the cylindrical chamber 2, controlled by suitable actuating means.

Of course, the dispenser apparatus can be connected to conduits 12 receiving the basic soap from the above supply conduit or system. According to a formulation of the invention, the apparatuses are mechanically associated, i.e. integral, with a single central shaft 11.

FIRST EMBODIMENT EXAMPLE

According to a possible embodiment, illustrated in detail in figs. 1 and 2, the new cooling chamber consists of a vertical cylindrical body, closed and provided with connections to the vacuum system, globally indicated by reference numeral 4 in the figures and preferably arranged at the top, and an extraction drawing device 3 at the bottom; the basic soap to be treated is introduced from above into a conduit that is concentric to shaft 11 of a scraper head configured to deposit a layer of soap of uniform thickness.

A structure 23 (which may be solid, as in the example, or reticulated, not shown) extends from shaft 11 in a radial direction with respect to the cylindrical chamber, ending in the vicinity of the inner wall with an integrated dispensing/scraper head 13.

As said, one or more soap conveying conduits 12 also extend radially from the shaft, which branching from the concentric conduit, are configured to reach head 13.

The head is essentially cup-shaped 14, where said cup 14 comprises an opening 24 facing towards and adjacent to the inner wall 8; cup 14 further comprises a portion 15 facing rearwardly with respect to a direction of rotation 17; in order to direct and deposit the soap on the inner wall 8 and therefore also calibrate the thickness thereof, an adequate distance is maintained on the rear portion 15 of cup 14; said portion 15 defines a calibrated outlet 16 which serves as the outlet of soap 20 after the rotation according to direction 17; the soap layer 20 pushed from the inner conduit is released on the inner wall 8 of chamber 2 and calibrated in thickness by the above opening 16.

The cup comprises, integrated into the front part with respect to the direction of rotation 17 and inclined with respect to the radial direction, a deflector element 18 configured to lift the soap layer 19 previously deposited and thus already dried, so as to detach it from the inner wall and drop it in the underlying extraction drawing device 3.

It follows that during one round, the product deposited by the dispensing head (cup-shaped rear portion) is dried and detached by the deflector (front portion).

In order to allow said rapid cooling of the basic soap, at least part of the outer enclosure of the cylindrical chamber 2 comprises an inner 8 and outer 9 double wall within the cavity of which an annular jacket 10 is defined, which comprises suitable inlet and outlet passages for a cooling fluid, preferably water, which once inside jacket 10 lowers the temperature of the inner wall and thus promotes the cooling process of the basic soap when deposited.

In essence, with the head described above the dispensing and scraper apparatuses are substantially integrated into a single element of a rotatable device. SECOND EMBODIMENT EXAMPLE

A further possible embodiment is illustrated in detail in figure 3; the cylindrical chamber is still the same and the operating principle of cooling and dispensing is the same; however, the above dispensing 5 and scraper 6 apparatuses are independent and arranged to operate one in advance on the other.

It appears from the figures that they are angularly spaced according to the reference numeral 21, so that only after the passage of the scraper apparatus 6, which removes and detaches the solidified soap 19 from the wall, a second dispenser apparatus deposits a subsequent fresh layer 20 that will be solidified before the subsequent passage of said scraper apparatus 6.

In this case, the complexity of the head is avoided by introducing two separate elements integral to a single rotatable shaft, with the advantages and drawbacks already described above.

Finally, for both proposed solutions, an alternative jacket is provided with chambers 10a, 10b, 10c separated by partitions 22 or smaller and independent jacket blocks so as to limit the portion of intervention on the cooling of wall 8, as already mentioned at the beginning of the description.

IN SUMMARY

The object of the invention is the unit for drying basic soap and the relative method, which involves performing at least one soap cooling step by conductive heat exchange, wherein cooling is obtained by conductive heat exchange between the soap spread by a dedicated system on a wall of a chamber and the cooling means circulating in a jacket applied outside the wall of the chamber.

Preferably, the wall is cooled by fluid circulating in a jacket formed on the body of the new cooling chamber.

A pre-cooling step is also contemplated by using a vacuum degree lower than those currently used in this type of production, with which the soap is only partially cooled.

The special system for introducing the soap into the apparatus eliminates or dramatically reduces the creation of soap dust, resulting in reduced operational and ecological problems, thus simplifying the vacuum system of the plant.