DE2360891A1 - MIXING DEVICE - Google Patents

Description

- PATENT LAWYERS!

D R- I NG, H. Fl N CKE D I PL-I NS. H. BOHR DIPL.-ING. S. STAEGER

Long distance call. '26 60 60

Telogrommei claim «Munich Poiticheckkonto: Munich 27044-802

Bank details Bay «r. Association ibank Munich, account 620 404

MappoNo. 23396. Dr.K / Hö

BiIIo in the answer qngsbsn

Case Dd 25676

β Munich e, December 6, 1973

IMPERIAL CHEMICAL INDUSTRIES LIMITED.
London, UK

"Mixing device"

PRIORITY: December 7, 1972 - Great Britain

The invention relates to mixing apparatus and, more particularly, to apparatus suitable for use in
Mixing the raw materials for polyurethane foams suitable,

It is well known that in the production of polyurethane · ^ Foams certain liquid starting materials must be intimately mixed with one another, namely an organic polyol

409824/08416

organic polyisocyanate, a blowing agent and additives such as e.g. catalysts, surfactants and fire retardants, after which the resulting mixture is then converted into a form in a cavity or the like. is delivered where a reaction between the starting materials takes place and the formation of the "foam" takes place.

Many different types of mixing devices already exist for mixing the foam raw materials. In general they have a mixing chamber into which the separate streams of the starting materials are introduced and from which the mixture obtained is dispensed, this chamber being any Includes type stirrer. . ·.

According to the invention, a device is now proposed, "which when mixing the starting materials for polyurethane foams and which has a mixing chamber which is provided with several inlets for the polymethane foam starting materials and an outlet for the mixture formed therefrom is provided, the volume of the mixing chamber being between predetermined limit, values can be changed.

A method by which the volume of the mixing chamber changes consists of applying pressure from outside the device to a diaphragm located in the mixing chamber, exercise, the movement of the diaphragm reducing or increasing the volume of the chamber.

By varying the volume of the mixing chamber, it is possible 'time, which remain the foam starting materials in the mixing chamber, and therefore the extent does in which the reaction mixture reacts when leaving the device _t

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to change. This possibility of change is often extreme important .. if for example the delivery of a foaming reaction mixture takes place on the back of a carpet, then the degree of penetration of the reaction mixture the carpet can be watched, and if it is too strong, then the volume of the mixing chamber can be increased, making a stronger reacted mixture is released, which- less in the carpet structure entry. The volume of the chamber is preferably variable by a factor of at least two.

Polyurethane foam starting materials made using the device according to the invention can be mixed are described in detail in the literature. The main starting materials are an organic polyisocyanate, an organic polyol and a blowing agent. These are usually also auxiliaries, such as catalysts, surface-active agents, crosslinking agents and flame retardants mixed in. In many cases it will be some of the starting materials are premixed so that only two or three streams of starting materials are left to be fed into the device according to the invention must be mixed. . . ". ■

An embodiment of a device according to the invention is will now be described in more detail with reference to the accompanying drawings.

In the drawings show: .-.

1 shows a longitudinal section through the mixing device; and Figure 2 is a cross-section through the device of Figure 1 on line A-A. :. ··. "

According to Fig. 1, the mixing device has an inlet block 1, a cylinder.2 and a. Outlet pipe 3, which can be disassembled for the purpose of cleaning. The stirrer 4

Λ09824 / 0848

-H-

is driven by a shaft 5 which passes through the entry block. The stirrer has a thread provided cylindrical part 6, which the chemicals from the inlet openings 7 in the body of the mixing device emotional. Per · flow of materials from the openings is through Limiter 8 controlled. The stirrer 4 is cut out so that two chambers 9 are created, which form the main volume of the mixing device form.

10 The. Cylinder 2 is lined with a rubber tube / that is held against the cylinder by peder rings 11 so that when pressure is applied to inlets 12 and 13, the tube expands into chambers 9 in layers 14 and 15, ⁴ thereby whose volume is reduced. Air cannot enter between the expanded envelopes, which is why they can be influenced independently.

The device enables the mixing time and the residence time of the mixed components to be varied by having the casings expands and thus changes the effective mixing volume.

₁ U -i ': C. H.

PATENT CLAIMS

409824/0848

Claims (3)

PATENT CLAIMS: Device dedicated to mixing polyurethane foam. is suitable starting materials, characterized in that it has a mixing chamber with several inlets for the raw materials of the polyurethane foam manu- • position and is provided with an outlet for the mixture formed therefrom, the volume of the. Mixing chamber between predetermined limits can be changed. 2. Apparatus according to claim 1, characterized in that the volume of the mixing chamber can be changed as a result, . that pressure. from outside the device is applied to an .in the Mixing chamber located diaphragm exerts, whereby due to a movement of the diaphragm, the volume of the mixing chamber is increased or decreased. 3. Apparatus according to claim 1 or 2, characterized in that. 'that the volume of the mixing chamber by a factor of at least 2 can be changed. -if.Ct '= "Kii Jh'L.-li; 3.H. BOH * 4098 24/08 48