DE2734920A1 - Mixer and feeder for foam spray gun - has component hoses and hot water hoses pref. inside reinforced sheath - Google Patents

Abstract

Two component synthetic materials, esp. for the spraying of foam, are mixed and delivered by an installation comprising a proportioning pump, a mixing head and two heated component hoses. The synthetic materials are fed separately from the pump to the mixing head and >=1 hot water hose runs in contact with and along each component hose. Pref. the component hoses run together with hot water hoses which form a closed loop, from the proportioning pump to the mixing head and back, inside a sheathing hose, in which further hoses and/or electrical conductors are also enclosed. An electrical heater is provided for the hot water supply which is transported by an IC engine circulating pump. The preheating of the components from supply is effected in heat exchangers supplied by the hot water circuit. A temp. measuring and indicating instrument is provided at the reversal point of the hot water circuit. Provides a system esp. applicable to the rough operating conditions on building sites, by which the heating of the components can be controlled more easily and more efficiently. In the event of a breakdown along the tubular sheath, the trouble is more easily and quickly located and remedied.

Description

Device for mixing and dispensing two

Component plastics with heated hoses The invention relates to a device for mixing and dispensing two-component plastics, in particular Spray mixing device for foam plastics, with a propulsion pump, a Mixing head and two heated component hoses through which the plastic components are fed separately from the proportion pump to the mixing head. With such Fixtures it comes down to the two plastic components before mixing to bring to the same temperature, this temperature depending on the individual Plastic stays in place and also when working outdoors pretty much must be adhered to. For devices that are used for mobile operation on construction sites are intended, for example for coating flat roofs, are the proportional pumps and other ancillary units mounted on a truck. The hose lines to the mixing head are assembled from individual parts as required and can be used as a whole be up to 120 m long.

In a known device, the hoses are electrically heated with the help of heating coils, which are incorporated into the hoses or are themselves wrap around them. However, it has been shown that especially in the rough operation The heating wires can easily break on construction sites. It is then extraordinary difficult to locate the fault or even to locate the defective part close. The electrical temperature control equipment required is exceptional expensive, since it also has to be able to handle changing hose lengths. From the known individual heating of the hoses results in the further disadvantage that the Failure of only one hose heater is relatively slow due to a growing one Quality deterioration of the plastic mixture makes noticeable and therefore always leads to high material losses and extensive rework.

The invention is based on the object of the above Conditions a simpler, more effective and more easily controllable heating system to propose for the component hoses, also in case of failure no such high consequential damage causes and easier troubleshooting and debugging allows starting from a device of the introductory closer designated type, this object is achieved according to the invention in that at least a hot water hose with mutual thermal contact on the component hoses is led along. In particular, it is proposed that the component hoses with two hot water hoses, one from the proportional pump to the mixing head and forming backward loops, grouped together and from a single, preferably thermally insulating and provided with a metal reinforcement sleeve tube are wrapped.

In known plastic injection molding systems are also used for cleaning of the spray nozzles, rinsing solutions are used during work breaks or compressed air is used blown through the nozzles. Also the hoses and / or possibly required for this electrical cable for the electrical energy required at the mixing head in addition to the four tubes mentioned in the casing tube.

The greatest advantage of the invention is the higher operational reliability, Hot water hoses are much more resistant to tensile stress and rough operation than the thin heating cables. In particular, water hoses reinforced with wire mesh can be used be used. Should a hose be injured anyway or on one If a leak occurs at the coupling point, this is caused by the leaking Water immediately noticeable and the relevant hose section can be changed quickly.

Through the aforementioned combination of the two component hoses with a back and forth water hose loop is an even one Heating both plastic components in the simplest possible way ensures what is reflected in an improvement in the quality of the work result. Appropriately the loop forms part of a closed hot water circuit, with the Water with a view to using such a device outdoors and in the an antifreeze agent can be added during the cold season. To warm the Water is preferably a thermostatically controlled electric water heater used. The circulation pump can be a cooling water pump, as it is in internal combustion engines is common. To control the presence of the desired working temperature It is best to have a temperature measuring and display device near the mixing head intended for the water temperature at the turning point of the loop. As soon as the internal Temperature equalization is achieved in the envelope tube, for which only a few minutes are required is the water temperature at this point for the operator at the mixing head a sure sign of the functionality of the whole device.

For initial heating of the individual items arriving from the storage containers In a known device, plastic components are electric water heaters intended. In a further development of the invention is being proposed, to replace these electric water heaters with heat exchangers, which also be fed with hot water. This can be done through a separate hot water circuit or by connecting to the hot water circuit for hose heating. The advantage here is the greater heat storage capacity and the last-mentioned Case an additional system simplification.

An exemplary embodiment of the invention is described below with reference to FIG Drawing explained in more detail. 1 shows a diagram of a spray mixing device for foam plastics and FIG. 2 shows the cross section of the hose line system used between the floor standing device containing the proportion pump and the spray gun.

With the only partially shown with regard to the invention Device is made of polyurethane foam for building purposes, especially flat roofs foamed. The device consists of a standing device 1, which is preferably in a Box body truck is built in, and from a spray gun 2 that has a overall with 3 designated hose arrangement is connected to the floor unit. The hose arrangement can be composed of sections and be up to 120 m long, so that it extends up to the roof and the spray gun 2 over the entire roof surface is movable.

The two components polyol and isocyanate are made using two Drum pumps 4 taken from two barrels 5 and over two heat on shear 6, which in the Floor-standing device 1 are installed, fed to a proportional pump 7. This is a special one Piston pump, which is also housed in the free-standing device. Also includes the Floor-standing device still has an air compressor, not shown. From the proportion pump 7 lead two component hoses 8 and 9 to the spray gun 2, whereby also a Compressed air hose not shown in FIG. 1 is carried along. The compressed air is used for cleaning the spray nozzles of the spray gun 2 during work breaks.

For hose heating and, in the example, also for preheating the components a hot water circuit is used. This consists of a circulation pump 10, a thermostatic one regulated electric water heater 11, the two heat exchangers 6, one Hot water hose 12, a temperature measuring device 13 and a hot water hose 14, which leads from the spray gun 2 back to the circulation pump 10.

Fig. 2 shows that the four hoses indicated in Fig. 1 8, 9, 12 and 14 together with an air hose 15 in a common heat insulating and sleeve tube 16 provided with an outer wire armouring run. In order to there is intimate thermal contact between the two hot water hoses along the entire length of the hose and the component tubing created. Because the warm water in the formed Looping every now and then will also be at the initial Heating up, in which a large heat gradient occurs in the hot water hoses, the heat is supplied approximately evenly over the entire length of the hose arrangement, since the hot start of the hot water hose 12 is the cooler end of the Hot water hose 14 is opposite. The temperature measuring device 13, which is at the turning point of the loop and is arranged in the vicinity of the spray gun 2, shows the middle one Water temperature, which largely corresponds to the desired plastic temperature.

The water heater 11 and the circulation pump 10 could also exclusively be used for hose heating or the heat exchanger 6 for preheating the components could be connected in parallel. The spaces in between of the jacket tube 16 could improve the thermal contact between the tubes be filled with a medium that conducts heat well.

It is also advantageous if a filling liquid is more specific Heat, e.g. an oil, is used.

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Claims (7)

Claims device for mixing and dispensing two-component plastics, in particular spray mixing device for foamed plastics, with a proportional pump, a mixing head and two heated component hoses through which the plastic components are fed separately from the proportion pump to the mixing head, characterized in that that at least one hot water hose (12, 14) in mutual thermal contact is guided along the component hoses (8, 9). 2. Apparatus according to claim 1, characterized in that the component hoses (8, 9) with two hot water hoses (12, 14), one of which is from the proportional pump (7) form a loop running to the mixing head (2) and back, as well as with if necessary required further hoses (15) and / or electrical cables combined and are encased by a single envelope tube (16). 3. Apparatus according to claim 2, characterized in that the loop forms part of a closed hot water circuit. 4. Device according to one of the preceding claims, characterized in that that a thermostatically controlled electric water heater (11) for heating of the water is provided. 5. Apparatus according to claim 4, characterized in that a cooling water pump is used for internal combustion engines as a circulation pump (10). 6. Device according to claim 3 or one of the following claims, characterized in that for the initial heating of the two of the storage containers (5) flowing plastic components heat exchangers (6) are provided which are connected to the hot water circuit for the hose heating are connected and from this be fed. 7. Apparatus according to claim 2, characterized in that in the Near the mixing head (2) a temperature measuring and display device (13) for the Water temperature is provided at the turning point of the loop.