WO2020216681A1

WO2020216681A1 - Mobile containment and mixing plant, and related method

Info

Publication number: WO2020216681A1
Application number: PCT/EP2020/060805
Authority: WO
Inventors: Efren MARTINEZ-PEREZ; Carlos GARCIA-VITAL; Salvador MEIJA-GOMEZ
Original assignee: Covestro Intellectual Property Gmbh & Co. Kg
Priority date: 2019-04-25
Filing date: 2020-04-17
Publication date: 2020-10-29

Abstract

Mobile containment and mixing unit (10) comprising a steel wheeled structure with a lower frame (11) for easy transportation, an upper frame (30) adapted to support two tanks (27) with cover (28) and agitators (46) mixing the content of the tank (27): an output tubing (41) leading the content of the tank (27) towards a pneumatic pump (25) mixing and pumping the content of the tanks to the mixing valve where content of the tanks (27) enters in contact with a fluid; it also has a return tubing (50) making possible that the fluid mixed inside the pneumatic pump passes through the static mixer (54) allowing homogenization of the mixture before returning again to the tanks (27). The invention is further directed to a method for the preparation of polyol mixtures using the mobile containment and mixing unit (10).

Description

MOBILE CONTAINMENT AND MIXING PLANT, AND RELATED METHOD

TECHNICAL FIELD

This invention relates to polyurethane foam technology, particularly the invention provides a mobile containment and mixing plant for producing polyol mixtures, comprising a wheeled-steel structure allowing to easily carry the mobile containment and mixing unit, the structure also houses two containment and mixing tanks to contain polyols, as well as additives or agents in smaller amounts than in tanks placed in industrial facilities, which allows testing of new foaming polyurethane compositions accordingly to customer requirements are fast and efficiently carried out, since there is no need to purge and handle large amounts of polyols, additives and agents in industrial premises; all this is carried out in a portable and compact unit that allows changes in compositions quickly with low-waste, leading to substantial economic benefits for the clients. The invention is further directed to a method for the preparation of polyol mixtures using the mobile containment and mixing unit. The polyol mixtures, in particular polyol mixtures already containing one or more blowing agents, provided by the inventive mixing plant can then be used to react with isocyanates to polyurethane foams.

BACKGROUND

This invention relates to polyurethane foaming technology, particularly polyurethane foam, which is obtained by mixing polyols, typically an ester or ether polyol with an ester or ether isocyanate as base components. The practice requires identifying the exact balance between polyol and isocyanate and, the combination of additives or agents to mix with the polyol for further combination with the isocyanate at the end-use device; often the mixtures are obtained by trial and error, since the mixture depends on the resins, additives and agents quality; also enhancement of resins with any other agents, additives or foaming agents are also required intending to fulfill a specific need, that the client may require, like a more or less dense foam, requiring some mechanical properties, such as flame -retardant or UV protection and so on; variations are almost unlimited. Iterations to obtain the correct mixture of polyol, additives or agents and isocyanate are complex, moreover when mixtures take place in large-size equipment in the production plant that are capable to hold hundreds of cubic meters of polyol, additives or agents, in the containment and mixing tanks and pipes, therefore testing for optimizing foaming takes a long time and incurs in high costs, also produces large amounts of waste; here is where this invention perfectly fits , thus it teaches the use of a mobile unit, capable to store the necessary amounts of polyol, as well as additives and foaming agents enabling low-cost testing without the need of modifying the industrial plant conditions, representing significant savings in materials, time and funds, among others; have to take into account that there is no need of purging the industrial plant, or to maintain the main storage tanks, mixing tanks (formulators) and the middle-storage tanks clean; what is just needed, is to disengage industrial plant equipment and connect the portable or mobile unit of the present invention, to the mixing unit and use end device.

Various efforts have been developed in the fluids containment and mixing techniques, the following prior art documents illustrate said efforts, the reference numbers stated therein corresponds to the elements disclosed in said prior art.

The Zwirlein document US 4’204’977, shows a polyurethane foaming plant consisting of a couple of tanks (4, 6) pressurized by a nitrogen tank (3); reagents kept inside the tanks (4, 6) are led through the transportation pipes and valves, and discharged into the mixing chamber (26). One of the tanks is in fluid connection with a pump , which in turn is connected to the mixing chamber by using an inlet valve, which means that the discharge is poured into the mixing chamber, and capable to be sent to the tank back, then the permanent recycling of solvent inside the mixing chamber is possible provided the user deems so appropriate.

Another document is the Baumberger document US 4’404’ 168, depicting an intermittent production plant of foamed polyurethane products, consisting of a mixing tank/reactor (3) which is dosed with isocyanate and polyol coming from the dosing tanks (4, 5), which are in turn fed by the pump; dosing into the mixing tank (3) polyol is firstly introduced in order to purge and drag the residues of the previous mixture towards the bottom of the tank (3), the quantity introduced also inhibits the possible chemical reactions with residues contained inside the tank, being also used to clean inside the tank (3), thus automatically cleaning the tank (3) by using an agitator (12); pouring isocyanate requires the agitator (12) is still; after the proper quantity of isocyanate is poured inside the tank (3) the agitator is powered again (12) vigorously mixing the components; once the mix has been finished, the tank (3) is tilted to pour its content into the mold where foaming will be carried out; all this process is automatically controlled by the electronic control.

The Kukesh et al. document US 4’809’909 disclose an apparatus and method for manufacturing plural component materials, especially rigid urethane structures, from reactive components. The system includes a source of a first component, a source of a second component, a sprayer for mixing the components and for dispensing the mixture therefrom, and a delivery system for delivering the components to the sprayer. The delivery system is designed to continuously recirculate the components from their respective sources to the sprayer and back to the sources and includes positive displacement piston pumps simultaneously driven by a single motor. The system further includes means for calibrating the rates of flow of the components in the delivery system and a chopper to direct reinforcing glass fibers into the component mixture dispensed from the sprayer.

Then, the previous documents fail in providing a portable or mobile unit capable to be carried into the foaming industrial plant and also capable to contain a sufficient amount of polyol, additives or agents necessary to run the required tests to improve mixing of polyol, additives or agents with isocyanate, in terms of the specific needs of the process or the client.

BRIEF DESCRIPTION OF THE INVENTION

The device for containment and supply of polyol and agents or additives object of the present invention comprises a lower frame structure with wheels in its corners for an ease of transportation, on which is adapted a pole per side with a couple of diagonal posts supporting the upper frame, strengthening the framework; within the structure at least two mixing tanks are placed, comprising a temperature control system operated by means of a heat exchanger that can be either a serpentine tube or jacket type, through which the cooling fluid runs cooled by an external chiller that is not part of this invention; the at least two tanks are equipped with agitators preferably with paddles driven by an electric motor which in preferred embodiment comprises a reduction gearmotor in between the paddle agitator shaft and the electric motor shaft achieving an optimal agitation speed inside the tanks; the at least two tanks are also fitted with pneumatic tubing providing pressurized air, causing that the tank interior is pressurized; it should be mentioned that outputs of each tank include pipes adapted at least with a control valve to regulate the fluid coming from the tanks to discharge the fluid into a pneumatic pump, which is intended to transport the fluid mixed from the two tanks towards the dosing valve in order for the mixture to finally be in contact with the isocyanate where is mixed again preparing the mixture for its final use; the pneumatic pump is also fitted with a return pipe towards the tanks, which allows that the fluid not reaching the dosing valve is sent back to the tanks. BRIEF DESCRIPTION OF FIGURES

The following figures are for illustrative purposes only.

Figure 1 shows a top view of the lower frame.

Figure 2 shows a side view of the structure bearing a tank. Figure 3 shows a top view of the upper frame.

Figure 4 shows a front view of the structure bearing the tanks.

Figure 5 represents a front view showing the tank attached to the agitator, cover, heat exchanger installed on top the tank, and multiple pipe connections.

Figure 6 represents a side view showing the tank attached to the agitator, agitator electric motor, cover, heat exchanger installed on top the tank, and multiple pipe connections.

Figure 6a is a side view of a single tank with no heat exchanger attached, where pump, tank, cover, electric motor, agitator and related pipes can be distinguished.

Figure 6b is a front view showing at least two tanks with no heat exchanger attached, where pump, tank, cover, electric motor, agitator and related pipes can be distinguished. Figure 7 is a front view of the mobile containment and mixing unit structure having at least two tanks, pump and pipes.

DETAILED DESCRIPTION OF THE INVENTION

The following description generally refers to figures 1 to 7 in an indistinct manner.

A top view of the lower frame 11 of the mobile containment and mixing plant 10 as shown in figure 1, which will be called Pilot Plant 10 for simplification, comprises a couple of lower beams 12, helping to conform a mainly rectangular base; on the corners of the above referred frame 11 where a lower beam 12 is mechanically fixed to the lower crossbar 14 having a support plate 15 mechanically fixed to the underside of the lower frame 11; the abovementioned support plate 15 may have multiple openings to allow fixing a wheel 16 (shown in figure 2) that may be made, for illustrative purposes only, of gray rubber with a polypropylene core or black rubber with polypropylene core or black or gray solid rubber or polyurethane with a polypropylene core.

The lower beams 12, the lower crossbars 14, the lower middle bar 17 and the lower rail 18 may be made, for illustrative purposes only, of metal, ASTM A570 extruded structural steel“PTR” or equivalent is preferred, also the lower frame 11 may be preferably built from extruded structural aluminum; notwithstanding the material preferred, the components are mechanically fixed, to each other to conform a firm lower frame 11.

On the quarter built with the lower middle bar 17, the lower beam 12 and the lower rail 18 is installed a structure, made for instance of steel, such as ASTM A36 structural steel angle; the steel structure based on quarters comprises a couple of bars 19 made, for instance, from structural steel angle or alternatively from structural aluminum; as shown in Figure 1, the bars 19 are mechanically fixed in between the lower middle bar 17 and the lower beam 12, in between the bars 19 are mechanically fixed a couple of strips 36, for illustrative purposes only made of structural steel angle or alternatively from structural aluminum forming the inner quarter, which will hold a tray 20 made, for instance, from a steel sheet or alternatively from aluminum sheet; the steel structure formed by the bars 19 and strips 36 must be mechanically fixed to the bars 19; said bars 19 are mechanically fixed to the lower middle bar 17 and to the rear lower beam 12, the frame formed by the bars 19 and strips 36 serves to accommodate a tray 20 made, for illustrative purposes only, of steel plate or sheet (galvanized or cold rolled) and alternatively aluminum.

The support 21 of the pump 25 is placed and mechanically fixed on the lower middle bar 17 and the lower rail 18 intersection, which comprises a couple of parallel plates (not shown) separated by spacers that can be tubular, in a preferred embodiment the parallel plates (not shown) comprise a series of holes corresponding with the spacers, in such a way that the retaining screws of the pump 25 are capable to pass thru the plates and be sheathed into the spacers, tightened with nuts on the underside of parallel plate 22 that is fixed, for instance, mechanically fixed to the lower middle bar 17 and the lower rail 18.

On the lower rail 18 a column 34 is disposed, which is mechanically fixed to the above referred lower rail 18, the column 34 provides support to the at least two tanks 27 , and provides rigidity to the assembly formed by the upper frame 30, the lower frame 11 and posts 23; the column 34 in a preferred embodiment is manufactured with ASTM A570 PTR extruded steel; in an alternatively embodiment extruded aluminum can be used. Figure 2 shows a side view of the pilot plant 10, where the lower frame 11 is depicted on the corners of said lower frame 11 where the lower beams 12 and the lower crossbars 14 concur a post 23 that is mechanically fixed and is vertically installed, the aforementioned post 23 may be built in a preferred embodiment of squared ASTM A570 PTR extruded steel, and on an alternatively embodiment, for instance, made up with extruded aluminum; on the lower crossbar 14 is installed and mechanically fixed to a pillar 26 intended to hold the upper frame 30, and to provide rigidity to the assembly of the upper frame 30, the lower frame 11 and posts 23; the pillar 26 may be manufactured with ASTM A570 PTR extruded steel in some invention preferences, but in an alternative embodiment extruded aluminum may be used; the pillar 26 is fitted with a couple of diagonal reinforcements 24 which in its lower section are mechanically fixed to the lower crossbar 14, and mechanically fixed in its upper section to the pillar 26; diagonal reinforcements 24 may be built from ASTM A570 PTR extruded steel, but in an alternative embodiment extruded aluminum may be used.

Figure 3 represents a top view of the upper frame 30, which is installed on the posts 23 and on the pillars 26; similarly, the lower frame 11 and the upper frame 30 comprise a couple of upper beams 31 and a couple of upper crossbars 32 all of them joined in its edges and mechanically fixed; the upper crossbars 32 and the upper beams 31 may be manufactured in some embodiments from ASTM A570 PTR extruded steel, and in a preferred embodiment can be manufactured from extruded aluminum.

It should be noted that pillars 26 are crowned with a lateral bracket 33 that may be manufactured from cold rolled carbon steel sheet or in an alternative embodiment manufactured from aluminum; the lateral bracket 33 comprises an upper plate horizontally and mechanically fixed to the upper end of the pillar 26, such plate facing towards the tank 27; the above referred plate extends to the vicinity of the outer face of the tank 27, said plate in its lower section a rib is mechanically fixed perpendicular to the lower face of the plate; the rib is mechanically fixed along its edge contacting the lower side of the upper plate, and a horizontal edge of the rib is mechanically fixed to the pillar 26, in such a manner that the perpendicular rib becomes a reinforcement of the upper plate, thus between the upper plate and the rib the lateral bracket 33 is formed; the upper surface of the lateral bracket 33 is mechanically fixed to the upper crossbar 32 and the other end of the lateral bracket 33 is mechanically fixed to the peripheral ring 29 and the cover 28 of the tank 27.

It should be noted that the tank 27 comprises a peripheral ring 29 attached to the upper end on the tank 27 outer face, the above referred peripheral ring 29 may be steel made and mechanically fixed to the outer side of the tank 27, such peripheral ring 29 comprises a series of radial vertical thru holes corresponding with the cover 28 holes, in such a way that the cover 28 can be attached to the tank 27 peripheral ring 29 by means of screws with fastening means such as nuts, bolts or rivets; in a preferred embodiment the cover 28 as well as the mouth of the tank 27 have machined cylindrical lips in high and low relief used to conform a seal between the cover 28 and the mouth of the tank 27 once the screws are tightened; in another alternative embodiment the cover may host an o-ring (not shown) inside a machined low carved circular groove in the underside of the cover 28, in such a way that by placing the cover 28 on the mouth of the tank an airtight seal is created after tighten the screws with fastening means such as nuts, bolts or rivets; in an alternative embodiment, a preformed non-graphite Teflon carbon steel seal can be used, and in any other alternative embodiment soft metals such as zinc or aluminum, synthetic material or thermoplastic materials can be used, among others, therefore, by placing the cover 28 on the mouth of the tank 27 an airtight seal is formed after the screws are tightened; some of the holes of the peripheral ring 29 correspond to the holes of the lateral bracket 33 and to the central bracket 35 in such a way that the fastening means (for instance, screws with nuts, bolts or rivets) securing the cover 28 to the peripheral ring 29 also secure one end of the lateral bracket 33 to the central bracket 35; in an alternative embodiment said lateral bracket 33, may have an neckline with a radius larger than the external radius of the tank 27, which improves fit on the tank 27 periphery.

As shown in Figure 4, the upper frame 30 also comprises a central bracket 35, which similarly to the lateral brackets 33 comprises a horizontal plate lying between the external faces of the tanks 27; such a horizontal plate is mechanically fixed to the upper end of the column 34, having the lower perpendicular ribs mechanically fixed in its horizontal edges on opposite sides of the column 34, thus allowing that the upper edge is mechanically fixed to the lower side of the horizontal plate; both horizontal plate and the ribs conform the central bracket 35, the above referred horizontal plate and ribs of the central bracket 35 in a preferred embodiment may be steel manufactured, or in an alternative embodiment aluminum manufactured; the horizontal plate of the central bracket 35 lays in between the at least two tanks 27; similar to the lateral brackets 33, ends of the horizontal plate of the central bracket 35 next to the at least two tanks 37 comprise a series of thru holes corresponding with those of the peripheral rings 29 of each tank 27, in such a way that the fastening means such as screws with nuts, bolts or rivets fastening the cover 28 to the peripheral ring 29 of each tank 27 also fasten the corresponding ends of the horizontal plate of the central bracket 35; further in an alternative embodiment the edge of the horizontal plate of the central bracket 35 next to its corresponding tank 27 may have an neckline with a largest radius than the radius of the outer surface of its respective tank 27.

The above referred central bracket 35 has a mechanically fixed perch 56 on the upper face of the horizontal plate connecting the central bracket 35 to the upper rear beam 31; providing rigidity to the assembly of the central bracket 35 and the column 34; on the other hand, it also gives rigidity to the upper frame 30; which allows the support of the static and dynamic load of the at least the two tanks 27.

Both lateral brackets 33 and central bracket 35 are used to support the at least two tanks 27 as explained above, the upper section of the tank 27 is fitted with a peripheral ring 29 and multiple holes, mechanically fixing such peripheral ring to the outer face of tank 27, in such a way that the peripheral ring 29 and the tank 27 are held together permanently; the at least two tanks 27 are integrated to the structure conformed by the lower frame 11 and the upper frame 30; in such a way that brackets 33, 35 are responsible for supporting the tanks 27; as shown in Figure 4, it can be observed that the peripheral ring 29 is supported by at least two brackets 33, 35; to keep them in place, the cover 28 and peripheral ring 29 are secured by fastening means such as screws with nuts, bolts or rivets to the brackets 33, 35 if using nuts securing the screws nut torqueing is necessary; it should be remember that a series of holes of the peripheral ring 29 correspond with the brackets’ holes 33, 35.

The term“mechanically fixed” it has been used in order to eliminate tedious repetitions and is to be understood as any mechanically way to fix or put things together, in a preferred embodiment it comprises any type of welding (arch or wire); in other embodiments is not limited to the use of: screws with nuts, bolts, rivets, also comprises the use of binders (agglutinative) or glues (epoxy or cyanoacrylate for example); or any other means of strongly joining metals know in the art.

The at least two tanks 27 may be 285-C steel manufactured in some embodiments, in an alternatively preferred embodiment at least 70% of the outer cylindrical wall is covered with a heat exchanger 37 which comprises an inlet cooling pipe 38 at the end of which it is provided with a hydraulic couple to fit with the coolant supply coming from the temperature conditioning system in addition to a valve 43; the heat exchanger also comprises an outlet pipe 39 which at its end is provided with a valve coupled 44 to return the coolant back to the temperature conditioning system; in a preferred embodiment the above referred heat exchanger 37 is jacketed or double wall type, which typically comprises an outer cylinder installed at the external tank surface 27, the ends of the above referred outer cylinder are attached to the outer surface of the tank 27, in such a way that there is a sealed chamber between outer side of the tank 27 and the inner side of the outer cylinder of the tank 27, the sealed chamber allows free flowing of the coolant, allowing that the coolant is directly in contact with the outer surface of the tank 27 ; the system comprises an input cooling pipe 38 and an outlet pipe 39 of the coolant, making possible entry of the coolant and its return to the temperature conditioning system; in an alternative embodiment the heat exchanger 37 may be of shell and tube type, specifically designed to allow that at least two tanks 27 are capable to process high-viscosity fluids, such as base polyols (viscosities of 10,000 cps - 25,000 cps) at room temperature (considering 25°C the room temperature), in this embodiment the heat exchanger 37 also comprises a coolant input and output properly communicated with the inlet cooling pipe 38 and outlet pipe 39 of the temperature conditioning system, respectively; in an alternative embodiment, the heat exchanger 37 comprises a copper, steel or aluminum or other suitable metallic material serpentine tube coiled around the outer cylindrical wall of the tank 27 to be afterwards coated with an external steel or aluminum cylindrical wall; serpentine comprises a hydraulic coupling on one end to connect with the coolant supply pipe 39 coming from the temperature conditioning system in addition to a valve 44, the other end is adapted with a coupling on the pipe 38 with a valve 43 to allow return of the coolant to the temperature conditioning system; in such a way that under any modality the coolant flows between the heat exchanger 37 and the temperature conditioning system.

The temperature conditioning system can be thermal-heater type or, in an alternative embodiment a chiller, which typically use a cooling sealed system; some chiller models are capable to heat the coolant; chillers are typically adapted with a small cooling storage tank, an electrical pump, temperature sensors, temperature control system, as well as a valve system capable to control the mass flow of coolant supplied to the heat exchanger installed on the tank 27; such equipment’s are also adapted with features to heat or cool the coolant flow and to control the outlet temperature of the coolant fluid; the chiller as well as the peripheral temperature conditioning equipment are not subject of this invention.

In a preferred embodiment the tank 27 also comprises an agitation or stirring system, which includes a multipole squirrel cage induction motor 45 that may be electric or pneumatic, attached to the cover 28 by a plate and screws 28; the motor 45 is mechanically coupled to a gearmotor, the gearmotor output shaft passes through the hole on the cover 28 for that purpose, to be coupled then to a shaft supporting a series of blades or vanes that help transmit energy to the fluid inside the tank 27; both the shaft and blades are called agitator 46, the above referred agitator 46 may be manufactured, for instance, of stainless steel although as may be evident for a skilled artisan other suitable materials known in the art may be used; in an alternative embodiment the motor 45 can be an electric motor of variable speed, that is, the motor 45 can be adapted with a frequency variator, or in another embodiment a direct current motor may be used, such direct current motor might be coupled to an electronic control with PWM (Pulse Wide Modulation) controlling block with which the speed of the electric motor 45 is controlled; in another embodiment, motor 45 is powered by compressed air, that is motor 45 is a pneumatic motor, in this embodiment the motor 45 is supplied with compressed air and a branch from the pneumatic tubing 47 is disposed to each pneumatic motor 45, just before the pneumatic motor 45 air inlet a pressure regulator and maintenance unit (not shown) are disposed, they are in fluid communication to the pneumatic tubing 47, so the pressure to the pneumatic motor 45 can be controlled and therefore the speed of the pneumatic motor 45 can be regulated; it should be noted that embodiments allowing the speed of the motor 45 to be varied a gearmotor may not be required.

Figures 5a and 5b show the pipe installation or associated pipes of the at least two tanks 27, each tank 27 is fitted with pneumatic tubing 47 directly coupled to the cover 28, such tubing is used to provide pressurized air to the at least two tanks 27 and to the pump 25, and on an alternative embodiment to supply pressurized nitrogen for the at least to tanks 27 ; the above referred pneumatic pipes 47 may be made from T-304 Schedule 10 stainless steel; in an alternative embodiment any other metal capable to withstand 15 kg/cm2 or to withstand the work pressure required in its specific case; an example of said work pressure may be a pressure range from about 20 Bar to approximately 40 Bar, preferably from about 25 Bar to about 35 Bar, or else to be approximately 160 Bar, preferably 150 Bar; the pneumatic tubing 47 has a valve 48 that regulates the mass flow of the air or nitrogen towards the tank 27, also includes pressure gauge 49 to indicate the work pressure; the cover 28 is provided with a threaded hole through which a nipple is installed and used to be coupled to the pneumatic tubing 47, alternatively the cover 28 may have any type of pneumatic coupling available in the market that allows its connection and disconnection.

Within the present the first branch of the return tubing (50) running through the at least two tanks (25) comprises a first branch (bypass branch valve) comprising a bypass valve (53), and a second parallel branch (static mixer branch), such a second branch comprising a static mixer (54) suitable for homogenization of at least a part of the polyols formulation coming from the at least two tanks (27).

The invention relates in particular to the following embodiments: 1. A mobile containment and mixing unit 10 for preparation of polyol mixtures, the mixing unit 10 includes: at least two tanks 27, each one with an airtight cover 28 and an agitator 46; a pump 25; an output tubing 41 uninterruptedly connecting to the at least two tanks 27 and the pump 25; a pneumatic tubing 47 for introducing pressurized fluid to the at least two tanks 27 and the pump 25; a two-branch return tubing 50 the first branch of which is suitable to transport fluid released by the pump 25 to the at least two tanks 27 and the second branch of which maintains a permanent communication with a mixing valve; and a structure, supporting the at least two tanks 27 and the pump 25; where the first branch of the return tubing 50 running through the at least two tanks 25 comprises a first branch comprising a bypass valve 53 and a second parallel branch, such a second branch comprising a static mixer 54 suitable for homogenization of at least a part of the polyols formulation coming from the at least two tanks 27; where the first branch of the bypass of such return tubing 50 is led to the at least two tanks 27 and is fitted with a return valve 51 for allowing or restricting flow towards the at least two tanks 27 ; where the second branch of the bypass of such return tubing 50 that is in fluid communication with the mixing valve comprises a supply valve 55 to regulate the flow towards the mixing valve. 2. The mobile containment and mixing unit 10 in terms of embodiment 1, characterized in that the cover 28 of the tanks 27 is reversibly thereon, in particular by a screw-connection.

3. The mobile containment and mixing unit 10 according to embodiment 1 or 2, characterized in that the covers 28 of the tanks 27 include a naturally coupled nipple and a pressure gauge 49. 4. The mobile containment and mixing unit 10 according to any of the preceding embodiments, characterized in that the agitator 46 is driven by a motor 45 and in that the covers 28 of the tanks 27 are in particular prepared to support the motor 45 that drives the agitator 46.

5. The mobile containment and mixing unit 10 according to any of the preceding embodiments, characterized in that the pneumatic tubing 47 is suitable for supplying pressurized fluid to the at least two tanks 27 and the pump 25 is adapted with a pressure regulator with filter installed before the inlet of the pump 25 in order to control the flow - speed of the pressurized fluid.

6. The mobile containment and mixing unit 10 according to any of the preceding embodiments, characterized in that the structure comprises: a. a mainly rectangular lower frame 11 composed of two parallel crossbars 14 mechanically fixed on its ends to a couple of parallel lower beams 12, a support plate 15 mechanically fixed on each corner that supports with a wheel 16, a lower quarter comprising a lower rail 18 mechanically fixed on its ends to the lower beam 12 and lower middle bar 17; an inner quarter formed inside the lower quarter which comprises parallel bars 19 mechanically fixed on its ends to the lower middle bar 17 and the lower beam 12, a couple of parallel strips 36 mechanically fixed on its ends to the bars 19, where a tray 20 is held; b. a pump support 21 for the pump 25 on top of the lower frame 11 ; c. an upper frame 30 adapted with lateral 33 and central 35 brackets supporting the tanks 27; d. a pillar 26 with diagonal reinforcement 24 on each side of the lower frame 11 to support the upper frame 30; e. posts 23 installed at the lower frame 11 corners supporting the upper frame 30 corners; f. a column 34 installed on the lower rail 18 of the lower frame 11 , which supports the central bracket 35; and g. lateral 33 and central 35 brackets holding and supporting each tank 27. 7. The mobile containment and mixing unit 10 according to any of the preceding embodiments, characterized in that an outer face of the at least two tanks 27 is fitted with a heat exchanger 37 providing temperature control of the fluid within the at least two tanks 27.

8. The mobile containment and mixing unit 10 according to any of the preceding embodiments, characterized in that the structure is steel manufactured.

9. A method for producing a polyol mixture of at least two different polyols in a mobile containment and mixing unit 10 according to any of the preceding embodiments, characterized in that the at least two different polyols are provided individually in the at least two tanks 27, wherein optionally at least one additive is provided in one or both of the at least two tanks 27 ; the at least two polyols are fed through the output tubing 41 by the pump 25 partly or completely through the static mixer 54 of the two-branch return tubing 50 so that at least a part of the polyols is homogenized and led to the at least two tanks 27, wherein the flow towards the at least two tanks 27 can be restricted with return valves 51 , whereas the polyols are kept in circulation until completely homogenized so that the polyol mixture is obtained. In other words, after complete homogenization, the mixture in both tanks is the same. The additives are typical substances used in the production of polyurethane polymers, such as catalysts, surfactants, flame retardants, blowing agents and so on. In particular, physical blowing agents are used, which are otherwise difficult to incorporate in polyol formulations homogeneously.

10. The method according to embodiment 9, characterized in that at least one blowing agent is provided as additive, wherein the blowing agent is in particular a physical blowing agent.

For illustration purposes only, polyol formulations contained and treated within the tanks 27 to produce polyurethane comprises the following elements at approximately the following percentages by weight:

Ether or ester base polyols operating at 2.0 and 5.5 = 60 - 95%. Polyols SAN = 1.0 - 10%.

Ami die catalyzers = 0.5 - 5%.

Tin or phosphor metallic catalyzers = 0.05 - 1.5%. Surfactants = 0.5 - 5%.

Anti-flame additives = 5 - 20%.

UV additives = 0.01 - 3%.

Antioxidant additives = 0.01 - 1.0%. Stains and/or dyes = 0.5 - 5%.

Magnesium, carbonates or graphite loads = 0.5 - 4%.

Water = 0.05 - 10%.

Blowing agents = 0.05 - 30%.

Depending on the application and specifications required, quantity and type of materials of the formulation shall be determined.

The at least two tanks 27 have an output pipe 41 allowing transportation of the content of the tank 27 to the pump 25, said output tubing 41 may be T-304 Schedule 10 stainless steel manufactured; in an alternative embodiment carbon steel may also be used; the use of steel on any other materials is preferred since soft metals may catalyze with the formulation elements, and thermoplastics such as PVC are subject to attack by the acidic or basic character of the elements of the formulations; the aforementioned output tubing 41 is arranged at the lower section of the tank 27, through a threaded hole purposely made available for such effect at the bottom of the tank 27, where a nipple is screwed in providing connection with the remaining of the output tubing 41 or in an alternative embodiment the output tubing 41 is mechanically fixed to the lower section of the tank 27 in line with a hole made available at the bottom of the tank 27 for such purpose the aforementioned output tubing 41 further comprises an outlet valve 40 that regulates the mass flow of the contents of the tank towards the pump 25, it also comprises a purge valve 42 that helps directing the piping content to the trays 20 held in the lower frame 11.

The tanks 27 also include a return tubing 50 coming from the pump 25, such return tubing 50 may be T-304 Schedule 10 stainless steel manufactured; in an alternative embodiment another materials for piping with low internal roughness such as carbon steel supporting the work pressure and the inert content of the at least two tanks 27 can be used; the return tubing 50 is connected to the top of the cover 28, and the cover 28 includes a threaded hole to adapt a nipple used to connect the rest of the return tubing 50, in an alternative embodiment the return tubing 50 is mechanically fixed to the cover 28 aligned with the hole of the cover 28 for such purpose the concerned return tubing 50 also includes a return valve 51 that regulates the mass flow that goes into the tank 27.

It should be noted that the aforementioned tubing: pneumatic tubing 47, output tubing 41, return tubing 50 and any other capable to be used in this invention include its own fittings for routing, assembly, disassembly, maintenance and building, such as tubes, elbows, nipples, couplings, union nuts, tie plates, measuring devices, sensors, maintenance units (when applicable), among others, which must be known not requiring a detailed description.

Figures 6a, 6b and 7 show different views of at least two tanks 27, which for sake of simplicity and clarity the heat exchangers 37 are not shown, such figures show the pneumatic tubing 47, output tubing 41, also the return tubing 50; placing our attention on the pneumatic tubing 47 in a preferred embodiment it has a supply pipe 52 attached to the upper frame 30 by any fastening device, in an alternative embodiment the supply pipe 52 can be a pneumatic hose with couplings that fit the pneumatic tubing 47 just before each air flow valve 48; the air supply comes from an tank with an attached compressor; air free from oil and humidity is introduced to the tank 27 and as previously explained the cover 28 is hermetically coupled to the mouth of the tank 27, which allows to contain the pressure exerted by the compressed air inside the tank 27, the pneumatic tubing 47 includes a pressure gauge 49 installed on the cover 28, such pressure gauge must be capable to at least measure and support 15 mg/cm2 pressure; a branch of the aforementioned pneumatic tubing 47 provides pressure and air mass flow to the pump 25 which allows operation of the pump 25; the foregoing referred pump 25 is preferably an air driven pump (pneumatic) with pressures ranging from 1.5 bar up to 7 bar, double diaphragm, ball valve, specific for heavy duty, with pumping capacity of up to 511 1/min.

Paying attention to the output tubing 41, which comes from the bottom of the tank 27 leading the content of the tank 27 towards the pump 25; inside the pump 25 the content of each tank 27 is premixed; at the outlet of the pump 25 there is the return tubing 50, as shown in Figure 6a, also at the outlet of the pump 25 there is a fork with two branches, the first branch contains the mass flow coming from the pump 25 can be led to a bypass (which will be detailed below); the second branch is in fluid communication with the mixing valve where the polyol contained and treated within the tanks 27 comes into contact with the isocyanate; the mass flow of the polyol contained and treated within the tanks 27 led to the mixing valve can be controlled by the supply valve 55 or in an alternative embodiment is achieved by controlling the pump 25 operation speed, that can be achieved by regulating the pressure and flow of air entering the pump 25, for such purpose the pneumatic tubing 47 includes a pressure regulator with filter (not shown) before air supply coupling to the pump 25; to wit, work pressures of the pump 25 must be preferably between 4 bar to 7 bar (although the pump is capable to operate from 1.5 bar); making the pump 25 capable of providing 100 1/min to 500 1/min; in an alternative embodiment, it might be the case that the pneumatic tubing 47 is capable to operate at pressures higher than 7 bar, an example of such work pressure is from approximately 20 bar to 40 bar, preferably from approximately 25 bar to 35 bar, or else, to be approximately 160 bar, preferably 150 bar; in any case, the pump 25 flow regulator with filter is not only used to control the pump 25 operation speed and therefore control the flow, but also to be able to reduce the high pressure found inside the pneumatic tubing 47 and to be able to safely use the pump 25 work pressure specification which is 4 bar to 7 bar preferably. Under an alternative embodiment in which the work fluid of the pneumatic tubing 47 is nitrogen, the pump 25 and its pressure regulator with filter are disconnected from the pneumatic tubing 47 to be independently connected to any supply of pressurized air; thus, the pneumatic pipe 25 with pressure regulator and filter is capable to transport nitrogen without affecting the pump operation 25.

However, the first branch of the return tubing 50 leads the mass flow coming from the pump 25 towards a bypass conformed by a pair of parallel branches, where one of them comprises a bypass valve 53 that regulates the flow passing through both parallel branches; the remaining parallel branch comprises a four elements static mixer 54, inside the static mixer 54 we can find a series of guide sheets separating and guiding the flow creating turbulence, axial vortexes and mass flow rotation of the flow coming from the pump 25, ensuring homogenization of the components of the mixture; the aforementioned static mixer 54 has the purpose of homogenizing materials passing through it (such material where stored in the at least two tanks 27), such material may contain in an exemplary embodiment more than two polyols, and liquid-phase additives each with different viscosity, also one or more foaming agents under liquid or gaseous stage can be incorporated depending on its boiling point; it may also be the case that the at least one tank 27 may only contain polyol and the other at least one tank 27 contains additives or foaming agents or both; or as the testing procedures are being executed, the final product might require adding of agents or additives to the at least two tanks 27 or in some way alter the formulation of the polyol-additives-foaming mixture; therefore, it is very important to homogenize the material contained in the at least two tanks 27, providing the user with flexibility to modify and graduate mixtures according to the requirements of the end product-; after the mixture or mass flow coming from the pump 25 has passed through the bypass, the return tubing 50 becomes separate again to guide the content to the at least two tanks 27.

Figure 7 shows the pilot plant 10 comprising a metallic structure, such as a steel structure, with a lower frame 11, with multiple wheels 16 for ease of transportation of the pilot plant 10 , an upper frame 30 supported and fastened by pillars 26 with reinforcements and a column 34, the upper frame 30 comprises at least a couple of lateral brackets 33 and a central bracket 35 provided with a perch 56, the brackets 33, 35 uphold the at least two tanks 27 with cover 28 and peripheral ring 29, the brackets 33, 35 support the tank 27 by means of the peripheral ring 29 since said peripheral ring 29 is seated atop the aforementioned brackets 33, 35, the above referred brackets 33, 35 further comprises a plurality of thru holes coincident with some holes of the peripheral ring 29 making possible to fasten the tank 27, the cover 28 and brackets 33, 35 with screws and nuts; a pump 25 is mechanically fixed to the lower frame by at least one support plate 21 with spacers; on the other hand, the at least two tanks 27 are arranged with three different tubing’s, a pneumatic tubing 47 providing the at least two tanks 27 and pump 25 with dry air flow and pressure of 4 bar to 7 bar, thus the pump 25 is capable to be operated, in an alternative embodiment the pneumatic tubing 47 may use nitrogen as the work fluid, then only the at least two tanks 27 are supplied with nitrogen pressure and flow, thus allowing the pump 25 operates with compressed air, taking notice that in this embodiment the pump 25 is not connected to the pneumatic tubing 47, an output tubing 41 coming from the bottom of the at least two tanks 27 that transports the content of the at least two tanks 27 towards the pump 25, said pump 25 pumps and mixes the content of such tanks 27 to deliver the mixture whether: to the mixing valve to enter into contact with an additional fluid, such as isocyanate in the exemplary embodiment, or to recirculate the mixture towards the at least two tanks 27, without forgetting that the mixture coming from the pump 25 must pass through the two parallel branches of the bypass, said bypass is capable of regulating the mixture mass flow released by the pump 25; one of the branches contains the static mixer 54 suitable to homogenize the mixture contained in the at least two tanks 27, such material is capable to contain more than two polyols, as well as liquid-stage additives at different viscosities; to wit: raw materials such as base polyols used in polyurethane polyols formulations are capable to change within ranges from 250 cps and over 20,000 cps, for which, as can be evident to a specialized technician, its management, feeding to the pilot plant 10, recirculation and final pumping represents a challenge, especially when mixed in situ, this becomes easy by using the mobile containment and mixing unit 10 of the present invention; it should be noted that some raw materials are flammable, then the use of electric motor or devices is not recommended, this is why a pneumatic pump 25 is used and the use of any other electric device is reduced at minimum; also, one or more foaming agents in liquid or gaseous stage can be incorporated depending on the boiling point; once the mixture has left the bypass, the return tubing 50 is divided again to return the mixture again to the at least two tanks 27.

In this way we have a pilot unit 10 with a wheeled structure providing easy location inside the user or client premises, also making possible to maintain a determined quantity of polyols, additives, agents or elements included in the polyurethane polyols formulations, in a safely manner to be able to mix them in at least two tanks 27 thanks to agitators 46, the use of the return tubing 50 allows the use of the static mixer 54 suitable to homogenize the mixture contained in the pilot unit 10, this specific design makes possible to test different polyols with different additives or agents, making flexible, quick and reliable the experiments, preventing waste of materials; to wit, by running these types of tests on the fixed industrial equipment tens of cubic meters of materials would be wasted per test or per iteration; to wit, it is required to purge the pipes and clean the tanks; such tasks can be avoided by the use of this invention, taking into consideration that in the industrial premises the polyols supplying hardware to the molds or formwork are not used, these are disconnected at the mixing valve level, and the pilot plant 10 is directly connected by the supply valve 55, evidencing how easy is to purge the circuit between the return tubing 50 and the output tubing 41, and tank 27 cleaning tasks are relatively easy to complete, this can be achieved by keep supplying mixture through the mixing valve of the client premises, this allows to keep experimentation until tanks 27 content is depleted, or otherwise to send additives or agents-free polyols to clean the circuit in between the return tubing 50, output tubing 41 and tanks 27; in such a manner that testing of different mixtures of polyols with agents or additives may only take few hours, and not a couple of days, considering that once the experimentation is finished, the client or user may immediately be capable to reconnect the fixed industrial equipment to the mixing valve and to resume the work without the need of changing the work mixture or control parameters.

Parts list:

Claims

1. A mobile containment and mixing unit (10) for preparation of polyol mixtures, the mixing unit (10) includes: at least two tanks (27), a pump (25); a pneumatic tubing (47) for introducing pressurized fluid to the at least two tanks (27) and the pump (25); a two-branch return tubing (50) the first branch of which is suitable to transport fluid released by the pump (25) to the at least two tanks (27) and the second branch of which maintains a permanent communication with a mixing valve, wherein the second branch of the bypass of such return tubing (50) that is in fluid communication with the mixing valve comprises a supply valve (55) to regulate the flow towards the mixing valve;; and a structure, supporting the at least two tanks (27) and the pump (25); characterized in that each of the at least two tanks (27) is equipped with an airtight cover (28) and an agitator (46) whereas the at least two tanks (27) and the pump (25) are uninterruptedly connected by an output tubing (41); where the first branch of the return tubing (50) running through the at least two tanks (25) comprises a first branch comprising a bypass valve (53) and a second parallel branch, such a second branch comprising a static mixer (54) suitable for homogenization of at least a part of the polyols formulation coming from the at least two tanks (27); and where the first branch of the bypass of such return tubing (50) is led to the at least two tanks (27) and is fitted with a return valve (51) for allowing or restricting flow towards the at least two tanks (27). 2. The mobile containment and mixing unit (10) according to claim 1, characterized in that the cover (28) of the tanks (27) is reversibly thereon, in particular by a screw-connection.

3. The mobile containment and mixing unit (10) according to claim 1 or 2, characterized in that the covers (28) of the tanks (27) include a naturally coupled nipple and a pressure gauge (49).

4. The mobile containment and mixing unit (10) according to any of the preceding claims, characterized in that the agitator (46) is driven by a motor (45) and in that the covers (28) of the tanks (27) are in particular prepared to support the motor (45) that drives the agitator (46).

5. The mobile containment and mixing unit (10) according to any of the preceding claims, characterized in that the pneumatic tubing (47) is suitable for supplying pressurized fluid to the at least two tanks (27) and the pump (25) is adapted with a pressure regulator with filter installed before the inlet of the pump (25) in order to control the flow - speed of the pressurized fluid. 6. The mobile containment and mixing unit (10) according to any of the preceding claims, characterized in that the structure comprises: a. a mainly rectangular lower frame (11) composed of two parallel crossbars (14) mechanically fixed on its ends to a couple of parallel lower beams (12), a support plate (15) mechanically fixed on each corner that supports with a wheel (16), a lower quarter comprising a lower rail (18) mechanically fixed on its ends to the lower beam (12) and lower middle bar (17); an inner quarter formed inside the lower quarter which comprises parallel bars (19) mechanically fixed on its ends to the lower middle bar (17) and the lower beam (12), a couple of parallel strips (36) mechanically fixed on its ends to the bars (19), where a tray (20) is held; b. a pump support (21) for the pump (25) on top of the lower frame (11); c. an upper frame (30) adapted with lateral (33) and central (35) brackets supporting the tanks

(27); d. a pillar (26) with diagonal reinforcement (24) on each side of the lower frame (11) to support the upper frame (30); e. posts (23) installed at the lower frame (11) corners supporting the upper frame (30) corners; f. a column (34) installed on the lower rail (18) of the lower frame (11), which supports the central bracket (35); and g. lateral (33) and central (35) brackets holding and supporting each tank (27).

7. The mobile containment and mixing unit (10) according to any of the preceding claims, characterized in that an outer face of the at least two tanks (27) is fitted with a heat exchanger (37) providing temperature control of the fluid within the at least two tanks (27). 8. The mobile containment and mixing unit (10) according to any of the preceding claims, characterized in that the structure is steel manufactured.

9. A method for producing a polyol mixture of at least two different polyols in a mobile containment and mixing unit (10) according to any of the preceding claims, characterized in that the at least two different polyols are provided individually in the at least two tanks (27), wherein optionally at least one additive is provided in one or both of the at least two tanks (27); the at least two polyols are fed through the output tubing (41) by the pump (25) partly or completely through the static mixer (54) of the two-branch return tubing (50) so that at least a part of the polyols is homogenized and led to the at least two tanks (27), wherein the flow towards the at least two tanks (27) can be restricted with return valves (51), whereas the polyols are kept in circulation until completely homogenized so that the polyol mixture is obtained.

10. The method according to claim 9, characterized in that at least one blowing agent is provided as additive, wherein the blowing agent is in particular a physical blowing agent.